ORCID Profile
0000-0002-4784-2382
Current Organisation
Australian National University
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Theoretical and Computational Chemistry not elsewhere classified | Theoretical And Computational Chemistry Not Elsewhere Classified | Condensed Matter Physics | Macromolecular and Materials Chemistry | Theory Of Materials | Nanotechnology not elsewhere classified | Condensed Matter Modelling and Density Functional Theory | Condensed Matter Physics—Structural Properties
Industry | Expanding Knowledge in the Chemical Sciences | Environmental health | Expanding Knowledge in the Physical Sciences | Other environmental aspects |
Publisher: Royal Society of Chemistry (RSC)
Date: 2007
DOI: 10.1039/B704037G
Publisher: Elsevier BV
Date: 11-2018
Publisher: Springer International Publishing
Date: 05-07-2017
Publisher: American Scientific Publishers
Date: 09-2005
DOI: 10.1166/JNN.2005.306
Abstract: The doping of the wide-band gap semiconductor diamond has led to the invention of many electronic and optoelectronic devices. Impurities can be introduced into diamond during chemical vapor deposition or high pressure-high temperature growth, resulting in materials with unusual physical and chemical properties. For electronic applications one of the main objectives in the doping of diamond is the production of p-type and n-type semiconductors materials however, the study of dopants in diamond nanoparticles is considered important for use in nanodevices, or as qubits for quantum computing. Such devices require that bonding of dopants in nanodiamond must be positioned substitutionally at a lattice site, and must exhibit minimal or no possibility of diffusion to the nanocrystallite surface. In light of these requirements, a number of computational studies have been undertaken to examine the stability of various dopants in various forms of nanocrystalline diamond. Presented here is a review of some such studies, undertaken using quantum mechanical based simulation methods, to provide an overview of the crystal stability of doped nanodiamond for use in diamondoid nanodevices.
Publisher: Wiley
Date: 09-02-2017
DOI: 10.1002/QUA.25361
Publisher: MDPI AG
Date: 16-03-2018
Abstract: Pancreatic cancer is a devastating disease with poor survival outcomes. Recent studies have shown that the addition of radiotherapy to chemotherapy in the setting of locally advanced pancreatic cancer did not improve overall survival outcome. These studies commonly utilize conventional radiotherapy treatment fractionation and technique (typically 3-D conformal radiotherapy or intensity modulated radiotherapy). Although no clear benefit in overall survival was demonstrated in those studies, those who received radiotherapy did have a clear benefit in terms of local control. Therefore, there is increasing interest in exploring different techniques and/or modality of radiotherapy and dose/fractionation. Stereotactic radiotherapy, which employs a hypofractionated regimen, has the potential advantage of delivering a high dose of radiation to the tumor in a short period of time (typically over 5 days) with minimal dose to the surrounding normal structures. Particle therapy such as proton and carbon ion therapy are being explored as potential radiation modality that could cause greater biological damage to the tumor compared to photon treatment, with rapid dose falloff resulting in minimal to no dose to adjacent structures. This review will discuss the current literature and emerging roles of stereotactic radiotherapy and particle therapy in pancreatic cancer.
Publisher: Wiley
Date: 09-10-2019
Publisher: The Royal Society of Chemistry
Date: 18-03-2014
Abstract: The exceptional mechanical, optical, surface and biocompatibility properties of nanodiamond have gained it much interest. Exhibiting the outstanding bulk properties of diamond at the nanoscale in the form of a film or small particle makes it an inexpensive alternative for many applications. Nanodiamond is the first comprehensive book on the subject. The book reviews the state of the art of nanodiamond films and particles covering the fundamentals of growth, purification and spectroscopy and some of its erse applications such as MEMS, drug delivery and biomarkers and biosensing. Specific chapters include the theory of nanodiamond, diamond nucleation, low temperature growth, diamond nanowires, electrochemistry of nanodiamond, nanodiamond flexible implants, and cell labelling with nanodiamond particles. Edited by a leading expert in nanodiamonds, this is the perfect resource for those new to, and active in, nanodiamond research and those interested in its applications.
Publisher: Elsevier BV
Date: 09-2020
Publisher: American Physical Society (APS)
Date: 09-05-2006
Publisher: American Association for Cancer Research (AACR)
Date: 15-04-2008
DOI: 10.1158/0008-5472.CAN-07-5664
Abstract: FoxP3 is a member of the forkhead family of transcription factors critically involved in the development and function of CD25+ regulatory T cells (Treg). Until recently, FoxP3 expression was thought to be restricted to the T-cell lineage. However, using immunohistochemistry and flow cytometric analysis of human melanoma tissue, we detected FoxP3 expression not only in the tumor infiltrating Treg but also in the melanoma cells themselves. FoxP3 is also widely expressed by established human melanoma cell lines (as determined by flow cytometry, PCR, and Western blot), as well as cell lines derived from other solid tumors. Normal B cells do not express FoxP3 however, expression could be induced after transformation with EBV in vitro and in vivo, suggesting that malignant transformation of healthy cells can induce FoxP3. In addition, a FOXP3 mRNA variant lacking exons 3 and 4 was identified in tumor cell lines but was absent from Treg. Interestingly, this alternative splicing event introduces a translation frame-shift that is predicted to encode a novel protein. Together, our results show that FoxP3, a key regulator of immune suppression, is not only expressed by Treg but also by melanoma cells, EBV-transformed B cells, and a wide variety of tumor cell lines. [Cancer Res 2008 (8):3001–9]
Publisher: Informa UK Limited
Date: 20-05-2002
Publisher: Springer Science and Business Media LLC
Date: 11-04-2010
Abstract: Nitrogen-vacancy colour centres in diamond can undergo strong, spin-sensitive optical transitions under ambient conditions, which makes them attractive for applications in quantum optics, nanoscale magnetometry and biolabelling. Although nitrogen-vacancy centres have been observed in aggregated detonation nanodiamonds and milled nanodiamonds, they have not been observed in very small isolated nanodiamonds. Here, we report the first direct observation of nitrogen-vacancy centres in discrete 5-nm nanodiamonds at room temperature, including evidence for intermittency in the luminescence (blinking) from the nanodiamonds. We also show that it is possible to control this blinking by modifying the surface of the nanodiamonds.
Publisher: Informa UK Limited
Date: 07-2003
Publisher: Royal Society of Chemistry (RSC)
Date: 2009
DOI: 10.1039/B813515K
Publisher: AIP Publishing
Date: 10-09-2012
DOI: 10.1063/1.4748972
Abstract: In this work, we report on the spectroscopy and dynamics of the quasi-linear S2 state of chlorocarbene, CHCl, and its deuterated isotopologue using optical-optical double resonance (OODR) spectroscopy through selected rovibronic levels of the S1 state. This study, which represents the first observation of the S2 state in CHCl, builds upon our recent examination of the corresponding state in CHF, where pronounced mode specificity was observed in the dynamics, with predissociation rates larger for levels containing bending excitation. In the present work, a total of 14 S2 state vibrational levels with angular momentum ℓ = 1 were observed for CHCl, and 34 levels for CDCl. The range of ℓ in this case was restricted by the pronounced Renner-Teller effect in the low-lying S1 levels, which severely reduces the fluorescence lifetime for levels with Ka & 0. Nonetheless, by exploiting different intermediate S1 levels, we observed progressions involving all three fundamental vibrations. For levels with long predissociation lifetimes, rotational constants were determined by measuring spectra through different intermediate J levels of the S1 state. Plots of the predissociation linewidth (lifetime) vs. energy for various S2 levels show an abrupt onset, which lies near the calculated threshold for elimination to form C(3P) + HCl on the triplet surface. Our experimental results are compared with a series of high level ab initio calculations, which included the use of a dynamically weighted full-valence CASSCF procedure, focusing maximum weight on the state of interest (the singlet and triplet states were computed separately). This was used as the reference for subsequent Davidson-corrected MRCI(+Q) calculations. These calculations reveal the presence of multiple conical intersections in the singlet manifold.
Publisher: Informa UK Limited
Date: 05-2005
Publisher: Wiley
Date: 07-12-2022
Abstract: In this study a new approach to inverse design is presented that draws on the multi‐functionality of nanomaterials and uses sets of properties to predict a unique nanoparticle structure. This approach involves multi‐target regression and uses a precursory forward structure roperty prediction to focus the model on the most important characteristics before inverting the problem and simultaneously predicting multiple structural features of a single nanoparticle. The workflow is general, as demonstrated on two nanoparticle data sets, and can rapidly predict property/structure relationships to guide further research and development without the need for additional optimization or high‐throughput s ling.
Publisher: IOP Publishing
Date: 17-03-2020
Abstract: Many functional properties of particle system rely on collective behaviour and the type of superstructures formed when thousands of particles come together. Self-assembly, agglomeration and aggregation depend sensitively on the size and shape of particles present, as well as the size distribution and the mixtures of shapes within a given s le, which makes simulation of these superstructures and their properties challenging. Here we present a new, flexible, software package for the simulations of ordered and disorder aggregates of faceted polyhedral particle from the nanoscale to the micron-scale, which is capable of including size distributions and mixtures of multiple particle shapes defined by the User, subject to additional User-defined interactions. Following relaxation using molecular dynamics a number of characterisation tools are provided, including interfacial probabilities and distribution functions. The software is applicable to a range of problems from nanoparticle assembly to additive manufacturing.
Publisher: No publisher found
Date: 2014
Publisher: No publisher found
Date: 2014
Publisher: Wiley
Date: 30-06-2006
Abstract: Although a number of computational studies have examined the relative stability of icosahedral and decahedral gold clusters from 1 to 3 nm in size, few studies have focussed on the variety of face-centered cubic (fcc) nanoparticles in this size regime. In most cases small fcc gold particles are assumed to adopt the truncated octahedral shape, but in light of the fact that the shape and structure of gold nanoparticles is known to vary, the relative stability of fcc polyhedra may change with size. Presented here are results of first-principles calculations investigating the preferred shape of gold particles less than 3 nm in size. Our results indicate that the equilibrium shape of fcc gold nanoparticles less than 1 nm is the cuboctahedron, but this shape rapidly becomes energetically unstable with respect to the truncated octahedron, octahedron and truncated cube shapes as the size increases.
Publisher: American Chemical Society (ACS)
Date: 07-09-2006
DOI: 10.1021/JP0634252
Abstract: Although boron has been known for many years to be a successful dopant in bulk diamond, efficient doping of nanocrystalline diamond with boron is still being developed. In general, the location, configuration, and bonding structure of boron in nanodiamond is still unknown, including the fundamental question of whether it is located within grains or grain boundaries of thin films and whether it is within the core or at the surface of nanoparticles. Presented here are density functional tight-binding simulations examining the configuration, potential energy surface, and electronic charge of substitutional boron in various types of nanocrystalline diamond. The results predict that boron is likely to be positioned at the surface of isolated particles and at the grain boundary of thin-film s les.
Publisher: Informa UK Limited
Date: 2004
Publisher: Cambridge University Press (CUP)
Date: 2016
DOI: 10.1017/DSJ.2016.12
Abstract: Although nanoparticles have been shown to have clear technological advantages, their use in some consumer products remains controversial, particularly where these products come in direct contact with our bodies. There has been much discussion about using metal oxide nanoparticles in sunscreens, and numerous technology assessments aimed at predicting the type, size and concentration of nanoparticles and surface treatments that will be best for consumers. Yet, the optimal configuration is ultimately the one that people actually want and are willing to pay for, but until now consumer preferences have not been included in model predictions. We describe and discuss a proof of concept study in which we design and implement a hypothetical sunscreen product configurator to predict how people tradeoff sun protection factor (SPF), product transparency and potential toxicity from reactive oxygen species (ROS) in configuring their most preferred sunscreen. We also show that preferred nanoparticle sizes and concentrations vary across demographic groups. Our results suggest that while consumers choose to reduce or eliminate potential toxicity when possible, they do not automatically sacrifice high SPF and product transparency to avoid the possibility of toxicity from ROS. We discuss some advantages of using product configurators to study potential product designs and suggest some future research possibilities.
Publisher: American Chemical Society (ACS)
Date: 28-01-2014
DOI: 10.1021/JP410652S
Publisher: No publisher found
Date: 2014
Publisher: American Chemical Society (ACS)
Date: 15-07-2003
DOI: 10.1021/NL034169X
Publisher: Elsevier BV
Date: 08-2022
Publisher: American Chemical Society (ACS)
Date: 07-08-2014
DOI: 10.1021/CG500558J
Publisher: No publisher found
Date: 2017
Publisher: Elsevier BV
Date: 06-2022
Publisher: Public Library of Science (PLoS)
Date: 11-02-2020
Publisher: Wiley
Date: 06-2006
Publisher: Wiley
Date: 16-01-2018
DOI: 10.1002/CNCR.31235
Abstract: There are few published studies to guide the treatment of carcinoma metastatic to the neck from an unknown primary (CUP). In this regard, the objective of the current study was to share the authors' current experience treating patients with CUP using intensity-modulated radiation therapy (IMRT), which principally targeted both sides of the neck, the nasopharynx, and the oropharynx. This was a retrospective study in which an institutional database search was conducted to identify patients with CUP who received IMRT. Data analysis included frequency tabulation, survival analysis, and multivariable analysis. Two-hundred sixty patients met inclusion criteria. The most common lymph node category was N2b (54%). IMRT volumes included the entire pharyngolaryngeal mucosa in 78 patients, the nasopharynx and oropharynx in 167 patients, and treatment limited to the involved neck in 11 patients. Eighty-four patients underwent neck dissections. The 5-year overall survival, regional control, and distant metastases-free survival rates were 84%, 91%, and 94%, respectively. Over 40% of patients had gastrostomy tubes during therapy, and 7% patients were diagnosed with chronic radiation-associated dysphagia. Higher lymph node burden was associated with worse disease-related outcomes, and in subgroup analysis, patients with human papillomavirus-associated disease had better outcomes. No therapeutic modality was statistically associated with either disease-related outcomes or toxicity. Comprehensive IMRT with treatment to both sides of the neck and to the oropharyngeal and nasopharyngeal mucosa results in high rates of disease control and survival. The investigators were unable to demonstrate that treatment intensification with chemotherapy or surgery added benefit or excessive toxicity. Cancer 2018 :1415-27. © 2018 American Cancer Society.
Publisher: American Scientific Publishers
Date: 10-2004
Publisher: American Chemical Society (ACS)
Date: 05-05-2005
DOI: 10.1021/CM0502018
Publisher: Elsevier BV
Date: 2019
DOI: 10.1016/J.IJMEDINF.2018.10.008
Abstract: To implement a system for unsupervised extraction of tumor stage and prognostic data in patients with genitourinary cancers using clinicopathological and radiology text. A corpus of 1054 electronic notes (clinician notes, radiology reports and pathology reports) was annotated for tumor stage, prostate specific antigen (PSA) and Gleason grade. Annotations from five clinicians were reconciled to form a gold standard dataset. A training dataset of 386 documents was sequestered. The Medtex algorithm was adapted using the training dataset. Adapted Medtex equaled or exceeded human performance in most annotations, except for implicit M stage (F-measure of 0.69 vs 0.84) and PSA (0.92 vs 0.96). Overall Medtex performed with an F-measure of 0.86 compared to human annotations of 0.92. There was significant inter-observer variability when comparing human annotators to the gold standard. The Medtex algorithm performed similarly to human annotators for extracting stage and prognostic data from varied clinical texts.
Publisher: IOP Publishing
Date: 12-2019
Abstract: In this paper we revisit the structure of graphene oxide, and determine the pure and truly representative structures for graphene nanoflakes using machine learning. Using 20 396 random configurations relaxed at the electronic structure level, we observe the presence of hydroxyl, ether, double bonds, aliphatic (cyclohexane) disruption, defects and significant out-of-plane distortions that go beyond the Lerf–Klinowski model. Based on an erse list of 224 chemical, structural and topological features we identify 25 archetypal ‘pure’ graphene oxide structures which capture all of the complexity and ersity of the entire data set and three prototypes that are the truly representative averages in 224-dimensional space. Together these 28 structures, which are shown to be largely robust against changes in thermochemical conditions modeled using ab initio thermodynamics, can be downloaded and used collectively as a small data set for with a fraction of the computational cost in future work, or independently as an exemplar of graphene oxide with the required oxidation.
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2NR90005J
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2JM32640J
Publisher: Elsevier BV
Date: 05-2005
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C1JM13362D
Publisher: American Chemical Society (ACS)
Date: 06-10-2023
Publisher: Elsevier BV
Date: 04-2010
Publisher: Elsevier BV
Date: 11-2012
DOI: 10.1016/J.JCIS.2012.07.011
Abstract: Nanoparticulate hematite is a promising material for catalytic and photoelectrochemical applications, where the surfaces are engineered to improve efficiency in different chemical environments. In the presence of water, the surfaces are typically passivated by hydroxyl groups, which modify the surface stability and reactivity. We use density functional theory and first principles thermodynamics to investigate the low-index surfaces (001), (101), and (104) in hydrous environments. For each of the surfaces, we build various hydroxylation configurations and compare their thermodynamic stability under different environmental conditions (temperature, humidity, and supersaturation of oxygen). The results enable us to construct surface phase diagrams, which provide guidance to the selection of surface structures, and the control of environmental conditions for specific applications.
Publisher: IOP Publishing
Date: 23-06-2011
Publisher: Springer Science and Business Media LLC
Date: 04-2006
DOI: 10.1038/NMAT1625
Publisher: American Geophysical Union (AGU)
Date: 05-2021
DOI: 10.1029/2020EF001893
Abstract: Australia, the driest inhabited continent, is prone to natural disasters, such as droughts, floods, bushfires, and heatwaves. Strong climate variability causes recurring threats to water supply, agriculture, and the environment. Improving our insight into changes in hydroclimatic patterns is required to provide useful information for society. Previous studies mainly focused on the causes of extreme wet or dry events in specific periods and their impacts on agriculture and ecosystems. An understanding of long‐term spatio‐temporal patterns of wetting and drying in Australia is still lacking. Here we show, based on analyses of Gravity Recovery and Climate Experiment satellite derived terrestrial water storage and extended datasets, that there are four consecutive periods of seesaw wetting and drying between eastern and western Australia in the past five decades. The seesaw phenomenon is characterized by eastern Australia gaining water, while western Australia is losing water, and vice versa. Strong La Niña induced continent‐wide wetting, resets this pattern, leaving each seesaw to last for 11 ± 5 years. We provide one possible mechanism related to vegetation response to climate variability and its feedback on hydrological processes to explain the seesaw pattern. The identified recurring seesaw pattern indicates that society would need to become more adaptive in managing forest, water, and disaster risks in the wake of a next strong La Niña induced continent‐wide wetting in Australia.
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2CP40530J
Abstract: This paper describes the equilibrium morphologies of zinc sulfide nanoparticles in the wurtzite phase as a function of size, determined using ab initio Density Functional Theory (DFT) simulations and a shape-dependent thermodynamic model predicting the Gibbs free energy of a nanoparticle. We investigate the relative stabilities of a variety of nanoparticle shapes based on the wurtzite structure and show how the aspect ratio of wurtzite nanorods moderates the size-dependent phase transformation to the zinc blende phase. We find that while wurtzite nanoparticles are thermodynamically unstable with respect to the low energy rhombic dodecahedron morphology in the zinc blende phase at all sizes, shape- and size-dependent phase transformations occur when other zinc blende morphologies are present. Despite popular synthesis of zinc sulphide nanoparticles in the wurtzite phase, an in-depth thermodynamic study relating to the relative stability of wurtzite shapes and comparison with the zinc blende phase does not exist. Therefore this is the first thermodynamic study describing how shape can determine the solid phase of zinc sulfide nanostructures, which will be of critical importance to experimental applications of nanostructured zinc sulfide, where phase and shape determines properties.
Publisher: American Chemical Society (ACS)
Date: 22-03-2011
DOI: 10.1021/JP1111026
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C1CP22508A
Abstract: A responsible approach to the development of alternative energy sources, storage and conversion systems is to utilize abundant materials, with minimal or no negative environmental impacts. Here we report that lepidocrocite (γ-FeOOH, a naturally occurring metastable phase of iron oxyhydroxide) shows great promise as a proton conductor, based on sophisticated first-principles calculations that include the important corrections of on-site Coulomb interactions for this strongly correlated material. Our results show how proton transfer is facilitated by phonon vibration modes and relatively low transition energy barriers.
Publisher: SPIE
Date: 10-03-2020
DOI: 10.1117/12.2549625
Publisher: American Chemical Society (ACS)
Date: 15-12-2005
DOI: 10.1021/CT0499635
Abstract: The potential of titanium dioxide nanoparticles for advanced photochemical applications has prompted a number of studies to analyze the size, phase, and morphology dependent properties. Previously we have used a thermodynamic model of nanoparticles as a function of size and shape to predict the phase stability of titanium dioxide nanoparticles, with particular attention given to the crossover of stability between the anatase and rutile phases. This work has now been extended to titanium dioxide nanoparticles in water, to examine the effects of various adsorption configurations on the equilibrium shape and the phase transition. Density functional calculations have been used to accurately determine surface energies and surface tension of low index hydrated stoichiometric surfaces of anatase and rutile, which are presented along with a brief outline of the surface structure. We have shown that morphology of TiO2 nanocrystals is affected by the presence of water, resulting in variations in the size of the (001) and (001̄) truncation facets in anatase, and a reduction in the aspect ratio of rutile nanocrystals. Our results also highlight that the consideration of hydrated nanocrystal surfaces is necessary to accurately predict the correct size dependence of the anatase to rutile phase transition.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0NH00382D
Abstract: Unsupervised clustering and supervised classification of a erse set of reconstructed, twinned and passivated diamond nanoparticles predict nine classes that have distinctly different characteristics and electronic properties.
Publisher: Elsevier
Date: 2006
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3NR05344J
Abstract: The discovery of the multipolar surface electrostatic potential on faceted diamond nanoparticles explained numerous observations over the past decades, but also raised questions as to how it could be reconciled with seemingly contradictory observations of micron sized diamond and bulk diamond surfaces. It was also unclear how surface electrostatic potential would vary for more quasi-spherical shapes, and derivatives of the ideal truncated octahedron. Here we present new results examining the size-dependence of the multi-polar surface electrostatic potential up to experimentally relevant sizes, and explore the impact of {110} facets which have been shown to present in reasonable quantities (experimentally). We have used computational methods that are consistent with previous work to allow for a direct comparison, and show that both particle size and the fraction of {110} facets on nanodiamond play a critical role in the surface charge. When the particle size is below ~2.5 nm multipoles are likely to dominate, but over ~3.0 nm the {110} facets efficiently neutralize the charges leading to a practically monopolar distribution, consistent with observations at other length scales.
Publisher: American Chemical Society (ACS)
Date: 25-05-2022
Publisher: American Chemical Society (ACS)
Date: 21-04-2016
Publisher: AIP Publishing
Date: 12-09-2011
DOI: 10.1063/1.3633772
Abstract: In this work, we report on our full results of the dynamics of the quasi-linear, predissociated S2 state of the prototypical halocarbene, CHF, and its deuterated isotopomer CDF using optical-optical double resonance spectroscopy through the S1 state. Homogeneous linewidths were determined for a total of 51 S2 state vibrational levels with angular momenta in the range ℓ = 0 − 3 for CHF, and 76 levels for CDF. Progressions involving all three fundamental vibrations were observed. The linewidth data reveal pronounced mode specificity for both CHF and CDF, where pure bending states have the largest linewidths. For CDF, the linewidths are uniformly narrower. Calculated (CCSD(T)/aug-cc-pVQZ//MP2/aug-cc-pVQZ) stationary points on the CHF potential energy surface show that two dissociative pathways are available at the energies accessed in this experiment: dissociation on the triplet surface, over a barrier, to form C(3P) + HF, and dissociation to ground state CF + H products. The former is excluded as a primary channel based on the small spin-orbit coupling in this system. A 27-state dynamically weighted full-valence complete active space self-consistent field calculation was performed with maximal weight focused on the S2 state, which was then used as a reference for Davidson-corrected multireference configuration interaction calculations MRCI(+Q) of the three lowest A′ and two lowest A″ states. These calculations reveal the presence of multiple conical intersections in the singlet manifold. Consistent with our experimental results, the most important of these involves the repulsive S3 state, which conically intersects with S2 at linearity.
Publisher: Elsevier BV
Date: 02-2021
Publisher: Springer Science and Business Media LLC
Date: 10-03-2021
Publisher: American Scientific Publishers
Date: 02-2015
Abstract: Nanodiamond is a promising material for biological and medical applications, owning to its relatively inexpensive and large-scale synthesis, unique structure, and superior optical properties. However, most biomedical applications, such as drug delivery and bio-imaging, are dependent upon the precise control of the surfaces, and can be significantly affected by the type, distribution and stability of chemical funtionalisations of the nanodiamond surface. In this paper, recent studies on nanodiamonds and their biomedical applications by conjugating with different chemicals are reviewed, while highlighting the critical importance of surface chemical states for various applications.
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8NR07341D
Abstract: Machine learning is a useful tool to determine where computational resources should focus, such as choosing representative sizes and shapes of nanoparticles, prior to simulation.
Publisher: American Scientific Publishers
Date: 03-2008
DOI: 10.1166/JNN.2008.309
Abstract: The field emission properties of hybrid carbon nanotubes/nanodiamond structures produced by one-step chemical vapor deposition (CVD) process have been investigated in order to assess their application as electron emitters for cold cathodes. The electron emission properties of a series of s les have been investigated by current-pressure, current-voltage and current-time measurements with the aim of testing the emission stability under working conditions relevant to technological applications. Stable emission, high values of current density and lack of arcing have been observed during prolonged working cycles, and without degradation of the material structure.
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2NR31354E
Abstract: In recent years considerable attention has been given to methods for modifying and controlling the electronic and quantum mechanical properties of graphene quantum dots. However, as these types of properties are indirect consequences of the wavefunction of the material, a more efficient way of determining properties may be to engineer the wavefunction directly. One way of doing this may be via deliberate structural modifications, such as producing graphene nanostructures with specific sizes and shapes. In this paper we use quantum mechanical simulations to determine whether the wavefunction, quantified via the distribution of the highest occupied molecular orbital, has a direct and reliable relationship to the physical structure, and whether structural modifications can be useful for wavefunction engineering. We find that the wavefunction of small molecular graphene structures can be different from those of larger nanoscale counterparts, and the distribution of the highest occupied molecular orbital is strongly affected by the geometric shape (but only weakly by edge and corner terminations). This indicates that both size and shape may be more useful parameters in determining quantum mechanical and electronic properties, which should then be reasonably robust against variations in the chemical passivation or functionalisation around the circumference.
Publisher: IOP Publishing
Date: 10-10-2014
DOI: 10.1088/0957-4484/25/44/445702
Abstract: Many important reactions in biology and medicine involve proton abstraction and transfer, and it is integral to applications such as drug delivery. Unlike electrons, which are quantum mechanically delocalized, protons are instantaneously localized on specific residues in these reactions, which can be a distinct advantage. However, the introduction of nanoparticles, such as non-toxic nanodiamonds, to this field complicates matters, as the number of possible sites increases as the inverse radius of the particle. In this paper we present > 10(4) simulations that map the size- and shape-dependence of the deprotonation potential and proton affinity of nanodiamonds in the range 1.8-2.7 nm in average diameter. We find that while the average deprotonation potential and proton affinities decrease with size, the site-specific values are inhomogeneous over the surface of the particles, exhibiting strong shape-dependence. The proton affinity is strongly facet-dependent, whereas the deprotonation potential is edge/corner-dependent, which creates a type of spatial hysteresis in the transfer of protons to and from the nanodiamond, and provides new opportunities for selective functionalization.
Publisher: American Scientific Publishers
Date: 2004
DOI: 10.1166/JNN.2004.039
Abstract: Recent advances in the fabrication and characterization of semiconductor and metallic nanowires are meeting the high expectations of nanotechnolgists. Although diamond has remarkable electronic and chemical properties, development of diamond nanowires has been slow, while the development of carbon nanotube-based technologies continues at a furious pace. Recently, the theoretical and experimental observation of the transformation of nanodiamonds into carbon-onions (and vice versa) has led to a new intermediate phase of carbon, denoted "bucky diamond", with a diamond core encased in an carbon onion-like shell. These findings lead to the question of whether a similar transformation occurs in diamond nanowires. We used ab initio techniques to determine the relaxed structure of diamond nanowires with octahedral surface facets, with results exhibiting delamination of octahedral surfaces, and indicating the formation of "bucky-wires". The effects of surface hydrogenation upon this transition also is examined.
Publisher: American Chemical Society (ACS)
Date: 04-06-2014
DOI: 10.1021/NN502808Y
Abstract: Innovations in computational nanoscience have traditionally come in conjunction with experimental innovations, but uncertainty often surrounds the trustworthiness of in silico studies. While the accuracy of simulations has been improving every year, considerably less attention has focused on dealing with increasing complexity, which may be the source of concern. Creating more realistic virtual experiments (without sacrificing theoretical and numerical accuracy) remains challenging, particularly when we are confronted with the polydispersivity characteristic of extra silico s les. Fortunately, there are various theoretical methods that can be used in conjunction with first-principles simulations, not the least of which are the statistical tools and techniques promised by the emerging fields of materials informatics and data-driven sciences.
Publisher: Elsevier BV
Date: 10-2017
Publisher: Wiley
Date: 20-02-2022
Abstract: Although it has been well established that the stability and properties of graphene oxide nanostructure are strongly influenced by the concentration, type, and distribution of oxygen groups on the surface, there has yet to be a definitive way of predicting the thermochemical stability in advance of detailed and time‐consuming experimentation or simulation. In this study, a data set of over 60 000 unique graphene oxide nanoflakes and supervised machine learning methods are used to predict the probability of observation (stability) with perfect accuracy, based on a limited set of structural features that can be controlled in advance. A decision tree is used to show how the features determine the stability, and a neural network provides an equation to predict the thermodynamic stability of virtually any configuration in minutes. This enables researchers to use machine learning as research planning tool or to assist in analyzing results from microanalysis.
Publisher: Elsevier BV
Date: 11-2022
Publisher: American Chemical Society (ACS)
Date: 16-01-2008
DOI: 10.1021/JP077688N
Publisher: Informa UK Limited
Date: 24-06-2019
Publisher: Wiley
Date: 23-09-2018
DOI: 10.1002/CCR3.1788
Publisher: No publisher found
Date: 2017
Publisher: Cold Spring Harbor Laboratory
Date: 13-10-2020
DOI: 10.1101/2020.10.09.20208827
Abstract: Osteoradionecrosis (ORN) is a major side-effect of radiation therapy in oropharyngeal cancer (OPC) patients. In this study, we demonstrate that early prediction of ORN is possible by analyzing the temporal evolution of mandibular subvolumes receiving radiation. For our analysis, we use computed tomography (CT) scans from 21 OPC patients treated with Intensity Modulated Radiation Therapy (IMRT) with subsequent radiographically-proven ≥ grade II ORN, at three different time points: pre-IMRT, 2-months, and 6-months post-IMRT. For each patient, radiomic features were extracted from a mandibular subvolume that developed ORN and a control subvolume that received the same dose but did not develop ORN. We used a Multivariate Functional Principal Component Analysis (MFPCA) approach to characterize the temporal trajectories of these features. The proposed MFPCA model performs the best at classifying ORN vs Control subvolumes with an area under curve (AUC) = 0.74 (95% confidence interval (C.I.): 0.61-0.90), significantly outperforming existing approaches such as a pre-IMRT features model or a delta model based on changes at intermediate time points, i.e. at 2- and 6-month follow-up. This suggests that temporal trajectories of radiomics features derived from sequential pre- and post-RT CT scans can provide markers that are correlates of RT-induced mandibular injury, and consequently aid in earlier management of ORN.
Publisher: American Chemical Society (ACS)
Date: 12-04-2012
DOI: 10.1021/JZ3001823
Abstract: Porous platinum nanoparticles provide a route for the development of catalysts that use less platinum without sacrificing catalytic performance. Here, we examine porous platinum nanoparticles using a combination of in situ transmission electron microscopy and calculations based on a first-principles-parametrized thermodynamic model. Our experimental observations show that the initially irregular morphologies of the as-sythesized porous nanoparticles undergo changes at high temperatures to morphologies having faceted external surfaces with voids present in the interior of the particles. The increasing size of stable voids with increasing temperature, as predicted by the theoretical calculations, shows excellent agreement with the experimental findings. The results indicate that hollow-structured nanoparticles with an appropriate void-to-total-volume ratio can be stable at high temperatures.
Publisher: American Chemical Society (ACS)
Date: 05-10-2023
Publisher: American Chemical Society (ACS)
Date: 27-10-2011
DOI: 10.1021/JP207619X
Publisher: Elsevier BV
Date: 02-2023
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5RA26874E
Abstract: We demonstrate an approach for the use of data science methods for structural search for high-stability atomic structures in ab initio simulation, via the analysis of a large set of candidate structures.
Publisher: AIP Publishing
Date: 27-05-2003
DOI: 10.1063/1.1568935
Abstract: An ab initio density functional theory study of the structure and stability of a select group of dopants in a diamond nanocrystal is presented. The dopants studied here are boron and nitrogen. These atoms have been included substitutionally in the center of a 29 atom nanodiamond crystal, and the entire structure relaxed using the Vienna Ab Initio Simulation Package. The relaxed structures are then described by the relaxation energy, the structural (total) energy and a qualitative examination of the overall change in structure and bonding, considered via examination of the electron charge density. It is anticipated that these results will provide a better understanding of the crystal stability of doped nanodiamonds for use in diamondoid nanodevices.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4NR06123C
Abstract: Many of the promising new applications of graphene nanoflakes are moderated by charge transfer reactions occurring between defects, such as edges, and the surrounding environment. In this context the sign and value of properties such as the ionization potential, electron affinity, electronegativity and chemical hardness can be useful indicators of the efficiency of graphene nanoflakes for different reactions, and can help identify new application areas. However, as s les of graphene nanoflakes cannot necessarily be perfectly monodispersed, it is necessary to predict these properties for polydispersed ensembles of flakes, and provide a statistical solution. In this study we use some simple statistical methods, in combination with electronic structure simulations, to predict the charge transfer properties of different types of ensembles where restrictions have been placed on the ersity of the structures. By predicting quality factors for a variety of cases, we find that there is a clear motivation for restricting the sizes and suppressing certain morphologies to increase the selectivity and efficiency of charge transfer reactions even if s les cannot be completely purified.
Publisher: Copernicus GmbH
Date: 28-03-2022
DOI: 10.5194/EGUSPHERE-EGU22-6789
Abstract: & & Climate change has a significant impact on the environment by increasing the frequency of extreme precipitation events. Underestimating the potential risks of such events and lack of climate resilience will result in a substantial crisis in terms of water security. Understanding the hydrological consequences is difficult due to complexities and additional environmental feedbacks, depending on landuse/landcover, soil and climate.& & & & The Gravity Recovery and Climate Experiment (GRACE) has provided an unprecedented perspective on global fluctuations in terrestrial water storage (TWS) over the past decade. While numerous studies have correlated different hydrological variables against TWS, no study has tested different rainfall thresholds (intensity) impacting TWS. Existing studies mostly have explored the relationship between TWS anomalies and hydrological variables using in idual responses, while few have looked at multi-variable interaction. Single indicators (e.g., standardized precipitation index) may limit ecohydrological understanding of soil-vegetation-atmosphere water transfer, as many factors play essential roles in land-atmosphere interactions. In particular, rainfall characteristics can significantly impact the interaction between hydrological factors by accelerating or slowing processes. Hence, including appropriate temporal resolution of precipitation in analyses is essential e.g., monthly data are not a good indicator for understanding ecohydrological interactions. Therefore, this research aims to improve our understanding of the spatiotemporal response of TWS to climate change impacts on rainfall characteristics. Monthly GRACE TWS time series anomalies are analyzed against aggregated monthly rainfall with different daily thresholds (intensities). The obtained results are used to find explanatory variables such as land use/land cover, soil type, and climatic zones that determine the significance between TWS and various variables. The methodology provides a valuable insight into the mechanisms in which TWS is affected by rainfall characteristics at different spatiotemporal scales across various hydrological contexts across Australia.& &
Publisher: No publisher found
Date: 2017
Publisher: American Chemical Society (ACS)
Date: 18-07-2012
DOI: 10.1021/JP3063542
Publisher: Cold Spring Harbor Laboratory
Date: 09-06-2020
DOI: 10.1101/2020.06.08.20124974
Abstract: To describe the baseline and serial tumor microbiome in HPV-associated oropharynx cancer (OPC) over the course of radiotherapy (RT). Patients with newly diagnosed HPV-associated OPC treated with definitive radiotherapy +/- concurrent chemotherapy were enrolled in this prospective study. Using 16S rRNA gene sequencing, dynamic changes in tumor microbiome during RT were investigated. Surface tumor s les were obtained before RT and at week 1, 3 and 5 of RT. Radiological primary tumor response at mid-treatment was categorized as complete (CR) or partial (PR). Ten patients were enrolled. Mean age was 63 years (range: 51-71). As per AJCC 8 th Ed, 50%, 20% and 30% of patients had stage I, II and III, respectively. At 4-weeks, 7 patients had CR and 3 patients had PR at follow-up imaging post treatment, all patients had CR. Baseline ersity of tumoral and buccal microbiomes was not statistically different. For the entire cohort, alpha ersity was significantly decreased over the course of treatment (p=0.02). There was a significant alteration in the bacterial community within the first week of radiation. Baseline tumor alpha ersity of patients with CR was significantly higher than those with PR (p=0.03). While patients with CR had significant reduction in ersity over the course of radiation (p=0.02), the ersity remained unchanged in patients with PR. Patients with history of smoking had significantly increased abundance of Granulicatella (p=0.04), and Kingella (0.05) and lower abundance of Alloprevotella (p=0.04) compared to never smokers. The tumor microbiome of HPV-associated OPC exhibits reduced alpha ersity and altered taxa abundance over the course of radiotherapy. The baseline bacterial profiles of smokers vs. non-smokers were inherently different. Baseline tumor alpha ersity of patients with CR was higher than patients with PR, suggesting that the microbiome as a biomarker of radiation response deserves further investigation.
Publisher: Elsevier BV
Date: 07-2020
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4TA05317F
Abstract: Simultaneously enriching anatase s les with (001) facets and restricting the size to 30 nm or less can significantly increase the photocatalytic performance.
Publisher: American Chemical Society (ACS)
Date: 15-05-2020
DOI: 10.26434/CHEMRXIV.12300032.V1
Abstract: The outcome of machine learning is influenced by the features used to describe the data, and various metrics are used to measure model performance. In this study we use five different feature sets to describe the same 4000 gold nanoparticles, and 14 different machine learning methods to compare a total of 70 high scoring models. We then use classification and regression to show which meta-features of data sets or machine learning algorithms are important when making a selection. We find that number of features, and those that are strongly correlated, determine the class of model that should be used, but overall quality is almost entirely determined by the cross-validation score, regardless of the sophistication of the algorithm.
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C6NR06765D
Abstract: Controlling the structure of nanocrystals is an effective way to tune their properties and improve performance in a wide variety of applications. However, the atomic pathways for achieving this goal are difficult to identify and exercise, due to competing kinetic and thermodynamic influences during formation. In particular, an understanding of how symmetry, and symmetry breaking, determine nanocrystal morphology would significantly advance our ability to produce nanomaterials with prescribed functions. In this study we present results of a detailed computational study into the atomic structure of platinum nanoparticles at early growth stages of formation, as a function of temperature and atomic deposition rates. We investigate the impact of different types of crystalline seeds and characterize the emergent structures via simulated High Resolution Transmission Electron Microscopy (HRTEM) images. We find that the choice of initial seed is an important driver for symmetry breaking, due to a combination of atomic deposition and etching on different seed facets. A mix of low index facets causes the formation of important surface defects, in addition to the absorption/adsorption of single atoms, which can be correlated with different catalytic reactions as the process perpetuates. These findings provide new insights into nanocrystal shape-control mechanisms and suggest new opportunities for future design of this important class of nanomaterials.
Publisher: American Chemical Society (ACS)
Date: 19-08-2005
DOI: 10.1021/JP0524126
Abstract: The inclusion of dopants (such as nitrogen) in diamond nanoparticles is expected to be important for use in future nanodevices, such as qubits for quantum computing. Although most commercial diamond nanoparticles contain a small fraction of nitrogen, it is still unclear whether it is located within the core or at the surface of the nanoparticle. Presented here are density functional tight binding simulations examining the configuration, potential energy surface, and electronic charge of substitutional nitrogen in nanodiamond and bucky-diamond particles. The results predict that nitrogen is likely to be positioned at the surface of both hydrogenated nanodiamond and (dehydrogenated) bucky-diamond, and that the coordination of the dopants within the particles is dependent upon the surface structure.
Publisher: American Chemical Society (ACS)
Date: 11-07-2013
DOI: 10.1021/JP404200R
Publisher: IOP Publishing
Date: 02-06-2006
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C2EE23253G
Publisher: Elsevier BV
Date: 10-2003
Publisher: American Chemical Society (ACS)
Date: 13-04-2016
DOI: 10.1021/ACSCOMBSCI.5B00188
Abstract: Metal-organic frameworks (MOFs) are nanoporous materials with exceptional host-guest properties poised for groundbreaking innovations in gas separation applications according to high-throughput (HT) screening data. However, MOF structural libraries are nearly infinite in practice and so statistical and information technology will play a fundamental role in implementing and rationalizing MOF virtual screening. In this work, we apply k-means clustering and archetypal analysis (AA) to identify the truly significant nanoporous structures in a large library of ∼82 000 virtual MOFs. Quantitative structure-property relationship (QSPR) models of the theoretical CO2 and N2 uptake capacities were also developed using a calibration set of ∼16 000 hypothetical MOF structures derived from the prototypes and archetype frameworks. Since uptake capacities correlated poorly to the void fraction, surface area and pore size but these properties were used to build binary classifier predictors that successfully identify "high-performing" nanoporous materials in an external test set of ∼65 000 MOFs with accuracy higher than 94%. The accuracy of the classification decreased for MOFs with fluorine substituents. The classification models can serve as efficient filtering tools to detecting promising high-performing candidates at the early stage of virtual high-throughput screening of novel porous materials.
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7RA06622H
Abstract: Accurate predictions of nanocatalyst structure roperty relations can be made with large theoretical data sets, rather than limited sets of computational structures, in a fraction of the time using machine learning.
Publisher: IOP Publishing
Date: 08-12-2020
Abstract: The development of interpretable structure roperty relationships is a cornerstone of nanoscience, but can be challenging when the structural ersity and complexity exceeds our ability to characterise it. This is often the case for imperfect, disordered and amorphous nanoparticles, where even the nomenclature can be unspecific. Disordered platinum nanoparticles have exhibited superior performance for some reactions, which makes a systematic way of describing them highly desirable. In this study we have used a erse set of disorder platinum nanoparticles and machine learning to identify the pure and representative structures based on their similarity in 121 dimensions. We identify two prototypes that are representative of separable classes, and seven archetypes that are the pure structures on the convex hull with which all other possibilities can be described. Together these nine nanoparticles can explain all of the variance in the set, and can be described as either single crystal, twinned, spherical or branched with or without roughened surfaces. This forms a robust sub-set of platinum nanoparticle upon which to base further work, and provides a theoretical basis for discussing structure roperty relationships of platinum nanoparticles that are not geometrically ideal.
Publisher: Elsevier BV
Date: 09-2015
Publisher: Springer US
Date: 20-08-2021
Publisher: Human Kinetics
Date: 10-2023
Abstract: Background : Surveillance of domain-specific physical activity (PA) helps to target interventions to promote PA. We examined the sociodemographic correlates of domain-specific PA in New Zealand adults. Methods : A nationally representative s le of 13,887 adults completed the International PA Questionnaire–long form in 2019/20. Three measures of total and domain-specific (leisure, travel, home, and work) PA were calculated: (1) weekly participation, (2) mean weekly metabolic energy equivalent minutes (MET-min), and (3) median weekly MET-min among those who undertook PA. Results were weighted to the New Zealand adult population. Results : The average contribution of domain-specific activity to total PA was 37.5% for work activities (participation = 43.6% median participating MET-min = 2790), 31.9% for home activities (participation = 82.2% median participating MET-min = 1185), 19.4% for leisure activities (participation = 64.7% median participating MET-min = 933), and 11.2% for travel activities (participation = 64.0% median MET-min among participants = 495). Women accumulated more home PA and less work PA than men. Total PA was higher in middle-aged adults, with erse patterns by age within domains. Māori accumulated less leisure PA than New Zealand Europeans but higher total PA. Asian groups reported lower PA across all domains. Higher area deprivation was negatively associated with leisure PA. Sociodemographic patterns varied by measure. For ex le, gender was not associated with total PA participation, but men accumulated higher MET-min when taking part in PA than women. Conclusions : Inequalities in PA varied by domain and sociodemographic group. These results should be used to inform interventions to improve PA.
Publisher: Springer Science and Business Media LLC
Date: 07-03-2010
Abstract: Numerous reports have described the superior properties of nanoparticles and their erse range of applications. Issues of toxicity, workplace safety and environmental impact have also been a concern. Here we show a theoretical comparison of how the size of titanium dioxide nanoparticles and their concentration in sunscreens can affect efficacy, aesthetics and potential toxicity from free radical production. The simulation results reveal that, unless very small nanoparticles can be shown to be safe, there is no combination of particle size and concentration that will deliver optimal performance in terms of sun protection and aesthetics. Such a theoretical method complements well the experimental approach for identifying these characteristics.
Publisher: Informa UK Limited
Date: 21-03-2004
Publisher: The Royal Society
Date: 02-2023
DOI: 10.1098/RSOS.220360
Publisher: American Chemical Society (ACS)
Date: 03-06-2005
DOI: 10.1021/NL050355M
Abstract: The effects of surface chemistry on the morphology and phase stability of titanium dioxide nanoparticles have been investigated using a thermodynamic model based on surface free energies and surface tensions obtained from first principles calculations. It has been found that surfaces representing acidic and alkaline conditions have a significant influence on both the shape of the nanocrystals and the anatase-to-rutile transition size. The latter introduces the possibility of inducing phase transitions by changing the surface chemistry.
Publisher: Wiley
Date: 20-01-2011
Publisher: American Association for the Advancement of Science (AAAS)
Date: 09-12-2022
Abstract: In nature, snowflake ice crystals arrange themselves into erse symmetrical six-sided structures. We show an analogy of this when zinc (Zn) dissolves and crystallizes in liquid gallium (Ga). The low-melting-temperature Ga is used as a “metallic solvent” to synthesize a range of flake-like Zn crystals. We extract these metallic crystals from the liquid metal solvent by reducing its surface tension using a combination of electrocapillary modulation and vacuum filtration. The liquid metal–grown crystals feature high morphological ersity and persistent symmetry. The concept is expanded to other single and binary metal solutes and Ga-based solvents, with the growth mechanisms elucidated through ab initio simulation of interfacial stability. This strategy offers general routes for creating highly crystalline, shape-controlled metallic or multimetallic fine structures from liquid metal solvents.
Publisher: Wiley
Date: 15-12-2020
Publisher: Wiley
Date: 05-04-2022
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6NR01888B
Abstract: Detonation nanodiamond particles (DND) contain highly-stable nitrogen-vacancy (N-V) centers, making it important for quantum-optical and biotechnology applications. However, due to the small particle size, the N-V concentrations are believed to be intrinsically very low, spawning efforts to understand the formation of N-V centers and vacancies, and increase their concentration. Here we show that vacancies in DND can be detected and quantified using simulation-aided electron energy loss spectroscopy. Despite the small particle size, we find that vacancies exist at concentrations of about 1 at%. Based on this experimental finding, we use ab initio calculations to predict that about one fifth of vacancies in DND form N-V centers. The ability to directly detect and quantify vacancies in DND, and predict the corresponding N-V formation probability, has a significant impact to those emerging technologies where higher concentrations and better dispersion of N-V centres are critically required.
Publisher: Royal Society of Chemistry
Date: 2012
Publisher: Springer Science and Business Media LLC
Date: 06-2009
Abstract: Discussions of the potential risks and hazards associated with nanomaterials and nanoparticles tend to focus on the need for further experiments. However, theoretical and computational nanoscientists could also contribute by making their calculations more relevant to research into this area.
Publisher: IOP Publishing
Date: 24-04-2019
Publisher: Informa UK Limited
Date: 07-2003
Publisher: Cold Spring Harbor Laboratory
Date: 14-10-2020
DOI: 10.1101/2020.10.13.20211516
Abstract: Head and neck squamous cell carcinoma (HNSCC) treatment response relies heavily on macroscopic clinical findings. Blood monitoring of circulating markers during treatment may improve earlier detection of responders versus non-responders during radiotherapy. In this study, patients with intact tumour of HNSCC were enrolled in the prospective PREDICT-HN study. Pre-, after first treatment, weekly, and post-treatment blood s les were collected. CTC was enumerated using the CellSearch system. cfDNA was quantified from cfNA isolated at pre-, mid- and post-treatment timepoints. Blood s les were collected from 45 patients. Of the 339 s les analysed for CTC, 31% had detectable CTCs. Nine patients had detectable CTCs (1-3/7.5ml blood) in pre-treatment s les. After 1 fraction, 16 patients had CTCs detected, with 12 who had no pre-treatment CTC. Sixteen (36%) patients had detectable CTC in final week of treatment. There was no correlation between cancer stage, nodal status and tumour burden with CTC. cfDNA levels increased during treatment, with its highest level in the final week and lowest at post-treatment. Our results showed in HNSCC that CTCs can be detected during radiotherapy, suggesting mobilization into circulation during treatment, with as-yet-unknown viability. cfDNA kinetics during treatment correlated with CTC release, and may indicate apoptotic change. Head and neck squamous cell carcinoma (HNSCC) treatment response relies heavily on macroscopic clinical findings. Blood monitoring of circulating markers such as circulating tumour cell (CTC) and cell-free DNA (cfDNA) during treatment may improve earlier detection of responders versus non-responders during definitive radiotherapy. Although the detection of CTCs and cfDNA in patients with HNSCC has been described, there is minimal data on the kinetics of CTC counts and cfDNA levels during radiotherapy in patients with HNSCC. Here, our study prospectively describes the changes in CTC and cfDNA enumeration during radiotherapy in patients with HNSCC. Our results showed, for the first time to our knowledge, in HNSCC, that CTCs can be detected during radiotherapy, suggesting mobilization into peripheral circulation during treatment, with as-yet-unknown viability. cfDNA kinetics during treatment correlated with CTC release, may indicate apoptotic change during radiotherapy. Combined cfDNA-CTC as an early marker of treatment response should be investigated further.
Publisher: American Physical Society (APS)
Date: 29-08-2003
Publisher: Elsevier BV
Date: 10-2016
DOI: 10.1016/J.CHEMOSPHERE.2016.06.044
Abstract: Traditionally many structural alloys are protected by primer coatings loaded with corrosion inhibiting additives. Strontium Chromate (or other chromates) have been shown to be extremely effectively inhibitors, and find extensive use in protective primer formulations. Unfortunately, hexavalent chromium which imbues these coatings with their corrosion inhibiting properties is also highly toxic, and their use is being increasingly restricted by legislation. In this work we explore a novel tridimensional Quantitative-Structure Property Relationship (3D-QSPR) approach, comparative molecular surface analysis (CoMSA), which was developed to recognize "high-performing" corrosion inhibitor candidates from the distributions of electronegativity, polarizability and van der Waals volume on the molecular surfaces of 28 small organic molecules. Multivariate statistical analysis identified five prototypes molecules, which are capable of explaining 71% of the variance within the inhibitor data set whilst a further five molecules were also identified as archetypes, describing 75% of data variance. All active corrosion inhibitors, at a 80% threshold, were successfully recognized by the CoMSA model with adequate specificity and precision higher than 70% and 60%, respectively. The model was also capable of identifying structural patterns, that revealed reasonable starting points for where structural changes may augment corrosion inhibition efficacy. The presented methodology can be applied to other functional molecules and extended to cover structure-activity studies in a erse range of areas such as drug design and novel material discovery.
Publisher: Wiley
Date: 15-07-2018
Abstract: Achieving stability with highly active Ru nanoparticles for electrocatalysis is a major challenge for the oxygen evolution reaction. As improved stability of Ru catalysts has been shown for bulk surfaces with low-index facets, there is an opportunity to incorporate these stable facets into Ru nanoparticles. Now, a new solution synthesis is presented in which hexagonal close-packed structured Ru is grown on Au to form nanoparticles with 3D branches. Exposing low-index facets on these 3D branches creates stable reaction kinetics to achieve high activity and the highest stability observed for Ru nanoparticle oxygen evolution reaction catalysts. These design principles provide a synthetic strategy to achieve stable and active electrocatalysts.
Publisher: Elsevier BV
Date: 11-2018
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2JM33758D
Publisher: American Chemical Society (ACS)
Date: 26-03-2015
Publisher: Wiley
Date: 10-04-2017
DOI: 10.1002/JCC.24799
Abstract: Reverse Monte Carlo (RMC) simulations were performed to investigate the effectiveness of any combination of five experimentally motivated constraints on the reproduction of a test case, a ternary ab initio model. It was found that low energy structures fitting a variety of constraints commonly used in the RMC methodology could still provide an incorrect description of the chemical structural unit populations in multi-elemental systems. It is shown that the use of an elemental bond type constraint is an effective way to avoid this. © 2017 Wiley Periodicals, Inc.
Publisher: IOP Publishing
Date: 02-2013
DOI: 10.1088/0957-4484/24/8/085703
Abstract: While significant progress has been made toward production of monodispersed s les of a variety of nanoparticles, in cases such as diamond nanoparticles (nanodiamonds) a significant degree of polydispersivity persists, so scaling-up of laboratory applications to industrial levels has its challenges. In many cases, however, monodispersivity is not essential for reliable application, provided that the inevitable uncertainties are just as predictable as the functional properties. As computational methods of materials design are becoming more widespread, there is a growing need for robust methods for modeling ensembles of nanoparticles, that capture the structural complexity characteristic of real specimens. In this paper we present a simple statistical approach to modeling of ensembles of nanoparticles, and apply it to nanodiamond, based on sets of in idual simulations that have been carefully selected to describe specific structural sources that are responsible for scattering of fundamental properties, and that are typically difficult to eliminate experimentally. For the purposes of demonstration we show how scattering in the Fermi energy and the electronic band gap are related to different structural variations (sources), and how these results can be combined strategically to yield statistically significant predictions of the properties of an entire ensemble of nanodiamonds, rather than merely one in idual 'model' particle or a non-representative sub-set.
Publisher: American Chemical Society (ACS)
Date: 06-2005
DOI: 10.1021/JP051519Q
Abstract: Presented here is our continuing first-principles density functional theory study of the structural stability of a select group of dopants in diamond nanocrystals. On the basis of the work of others concerning dopants in diamond and endohedral atoms in fullerenes, the dopants selected for use here are oxygen, aluminum, silicon, phosphorus, and sulfur. These atoms were included substitutionally in the center of a 29-carbon-atom nanodiamond crystal, and each structure was relaxed using the Vienna Ab Initio Simulation Package. We describe the bonding and structure of the relaxed doped nanocrystals via examination of the electron charge density and point group symmetry. In combination with our previously reported results, it is anticipated that these results will assist in providing a better understanding of the mechanical stability of doped nanodiamonds for use in diamond nanodevices.
Publisher: AME Publishing Company
Date: 08-2018
Publisher: IOP Publishing
Date: 15-07-2010
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8NR01688G
Abstract: Diamond nanoparticles (nanodiamonds) are unique among carbon nanomaterials, and are quickly establishing a niché in the biomedical application domain.
Publisher: No publisher found
Date: 2016
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4NR01504E
Abstract: Observations of non-equilibrium morphologies in nanoparticle s les can be explained by treating the system as a statistical ensemble.
Publisher: World Scientific Pub Co Pte Lt
Date: 04-2003
DOI: 10.1142/S0218625X03004998
Abstract: Presented are results of our ab initio study of the surface reconstruction and relaxation of (100) surfaces on bulk and nanocrystalline diamond. We have used a density functional theory (DFT) within the generalized-gradient approximation (GGA) via the parallel computer version of the Vienna ab initio simulation package (VASP), to consider dehydrogenated and hydrogenated surfaces. Edges and corners of nanocrystals offer a new challenge in the determination of surface structure. We have applied the methodology for stepped diamond (100) surfaces to this problem, and consider it useful in describing nanodiamond edges and corners to first approximation. Our results also indicate that dimer lengths and atomic layer depths of the C(100)(2 × 1) and C(100)(2 × 1):H nanodiamond surfaces differ slightly from those of bulk diamond. The effects of these differences on crystalline stability are discussed, with the intension of offering a better understanding of the effects of nanodiamond surfaces on the stability of diamondoid nanostructures.
Publisher: Springer Science and Business Media LLC
Date: 11-2013
DOI: 10.1038/503463A
Publisher: American Chemical Society (ACS)
Date: 04-08-2009
DOI: 10.1021/CG900680E
Publisher: Springer Science and Business Media LLC
Date: 12-10-2015
DOI: 10.1007/S00394-015-1069-9
Abstract: To determine optimal body mass index (BMI) cut-points for the identification of cardiometabolic risk in black South African adults. We performed a cross-sectional study of a weighted s le of healthy black South Africans aged 25-65 years (721 men, 1386 women) from the North West and Free State Provinces. Demographic, lifestyle and anthropometric measures were taken, and blood pressure, fasting serum triglycerides, high-density lipoprotein (HDL) cholesterol and blood glucose were measured. We defined elevated cardiometabolic risk as having three or more risk factors according to international metabolic syndrome criteria. Receiver operating characteristic curves were applied to identify an optimal BMI cut-point for men and women. BMI had good diagnostic performance to identify clustering of three or more risk factors, as well as in idual risk factors: low HDL-cholesterol, elevated fasting glucose and triglycerides, with areas under the curve >.6, but not for high blood pressure. Optimal BMI cut-points averaged 22 kg/m In black South African men, a BMI cut-point of 22 kg/m
Publisher: IOP Publishing
Date: 15-12-2007
Publisher: Informa UK Limited
Date: 11-09-2016
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C1NR10108K
Abstract: Understanding nanodiamond functionalisation is of great importance for biological and medical applications. Here we examine the stabilities of oxygen, hydroxyl, and water functionalisation of the nanodiamonds using the self-consistent charge density functional tight-binding simulations. We find that the oxygen and hydroxyl termination are thermodynamically favourable and form strong C–O covalent bonds on the nanodiamond surface in an O2 and H2 gas reservoir, which confirms previous experiments. Yet, the thermodynamic stabilities of oxygen and hydroxyl functionalisation decrease dramatically in a water vapour reservoir. In contrast, H2O molecules are found to be physically adsorbed on the nanodiamond surface, and forced chemical adsorption results in decomposition of H2O. Moreover, the functionalisation efficiency is found to be facet dependent. The oxygen functionalisation prefers the {100} facets as opposed to alternative facets in an O2 and H2 gas reservoir. The hydroxyl functionalisation favors the {111} surfaces in an O2 and H2 reservoir and the {100} facets in a water vapour reservoir, respectively. This facet selectivity is found to be largely dependent upon the environmental temperature, chemical reservoir, and morphology of the nanodiamonds.
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C1JM11677K
Publisher: IOP Publishing
Date: 07-11-2006
DOI: 10.1088/0957-4484/17/22/029
Abstract: Following the recent low temperature synthesis of high quality and single crystal CdSe quantum nanowires, we have used a thermodynamic model to investigate the plausibility of axial-growth and oriented-attachment formation mechanisms. Using surface energies for clean and alkylamine-passivated CdSe surfaces reported elsewhere by Manna et al (2005 J. Phys. Chem. B 109 6183), we have compared equilibrium and metastable shapes of CdSe nanowires as a function of aspect ratio and axial orientation for different degrees of surface passivation. In general, the theoretical results support the oriented-attachment of low aspect quantum dots or nanorods, followed by coalescence to form high aspect [Formula: see text] quantum wires.
Publisher: American Chemical Society (ACS)
Date: 07-11-2008
DOI: 10.1021/NN800446W
Abstract: The incorporation of more experimentally relevant parameters into theoretical descriptions of nanomaterials is important for our understanding of the stability of nanostructures in different chemical environments. Using a size-, shape-, and temperature-dependent thermodynamic model we have generated the first phase map for anatase and rutile nanocrystals, that includes both the equilibrium shape and the affects of surface chemistry. The calculated phase map indicates that the equilibrium boundary between anatase and rutile nanocrystals is surface charge chemistry dependent, which relates to both their formation and postsynthesis environments.
Publisher: IOP Publishing
Date: 17-01-2012
DOI: 10.1088/0957-4484/23/6/065707
Abstract: Graphene nanoflakes provide a range of opportunities for engineering graphene for future applications, due to the large number of configurational degrees of freedom associated with the addition of different types of corners and edge states in the structure. Since these materials can, in principle, span the molecular to macroscale dimensions, the electronic properties may also be discrete or continuous, depending on the application in mind. However, since the widespread use of graphene nanoflakes will require them to be predictable, stable and robust against variations associated with some degree of structural polydispersivity, the development of a complete understanding of the relationship between structure, properties and property dispersion is essential. In this paper we used electronic structure computer simulations to model the thermodynamic, mechanical and electronic properties of trigonal graphene nanoflakes with acute (highly reactive) corners. We find that these acute corners introduce new features that are different to the obtuse corners characteristic of hexagonal graphene nanoflakes, as well as different electronic states in the vicinity of the Fermi level. The structure and properties are sensitive to size and functionalization, and may provide new insights into the engineering of graphene nanoflake components.
Publisher: Royal Society of Chemistry (RSC)
Date: 23-10-2014
DOI: 10.1039/C4NR05363J
Abstract: Stable and predictable functionalization of nanodiamond with carboxyl is an important first step in loading these materials with therapeutic agents, and the conjugation with proteins, cytochrome, antigen, and DNA. By creating a map of the adsorption strength of COOH, OH, O and H with atomic level resolution across the entire surface of an experimentally realistic nanodiamond, we have shown how the distribution is highly anisotropic, and depends on surface reconstructions, facet orientation, and ultimately the shape. This provides useful insights into how the structure of nanodiamond impacts the formation of COOH surface monolayers, and suggests that efforts to separate nanodiamonds by shape would be highly beneficial in the development of drug delivery vehicles targeted to specific treatment regimes.
Publisher: Elsevier BV
Date: 2022
Publisher: Elsevier BV
Date: 2011
Publisher: American Chemical Society (ACS)
Date: 12-2005
DOI: 10.1021/JP054279N
Abstract: Many of the unique properties of metallic nanoparticles are determined not only by their finite size but also by their shape, defined by the crystallographic orientation of the surface facets. These surfaces (and therefore the nanoparticles themselves) may differ in a number of ways, including surface atom densities, electronic structure, bonding, chemical reactivities, and thermodynamic properties. In the case of gold, it is known that the melting temperature of nanoparticles strongly depends on the crystal size and that the shape may alter considerably (and yet somewhat unpredictably) during annealing. In this work we use first principle calculations and a thermodynamic model to investigate the morphology of gold nanoparticles in the range 3-100 nm. The results predict that the equilibrium shape of gold nanoparticles is a modified truncated octahedron and that the (size-dependent) melting of such particles is preceded by a significant change in the nanoparticle's morphology.
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C0EE00287A
Publisher: Springer Science and Business Media LLC
Date: 06-2019
DOI: 10.1557/MRC.2019.36
Publisher: Wiley
Date: 07-2008
Publisher: Royal Society of Chemistry (RSC)
Date: 2009
DOI: 10.1039/B9NR00154A
Abstract: For the move from nanoscience to nanotechnology to be sustainable, it is important that the issues surrounding possible 'nano-hazards' be addressed before commercialization. The global push for more environmentally friendly, biodegradable products, means the introduction of the nanoparticles contained within these products into the ecosystem is an inevitability. When this happens, it is desirable to know how the hazardous properties may be affected, and what the potential hazards are. In this article, a number of strategies will be discussed, combining the desirable aspects of theory, simulation, experiment and observation, and leading to predictions for incorporation into preventative frameworks. Particular attention will be given to the role of theory and computation, and how it intersects with the participants from complementary fields.
Publisher: American Scientific Publishers
Date: 11-2008
Publisher: Springer Science and Business Media LLC
Date: 30-01-2021
Publisher: American Chemical Society (ACS)
Date: 18-07-2007
DOI: 10.1021/JP0738199
Publisher: American Chemical Society (ACS)
Date: 21-05-2020
DOI: 10.26434/CHEMRXIV.12344459.V1
Abstract: Computer simulations and machine learning provide complementary ways of identifying structure roperty relationships that are typically targeting toward predicting the ideal singular structure to maximise the performance on a given application. This can be inconsistent with experimental observations that measure the collective properties of entire s les of structures that contain distributions or mixture of structures, even when synthesized and processed with care. Metallic nanoparticle catalysts are an important ex le. In this study we have used a multi-stage machine learning workflow to identify the correct structure roperty relationships of Pt nanoparticles relevant to oxygen reduction (ORR), hydrogen oxidation (HOR) and hydrogen evolution (HER) reactions. By including classification prior to regression we identified two distinct classes of nanoparticles, and subsequently generate the class-specific models based on experimentally relevant criteria that are consistent with observations. These multi-structure/multi-property relationships, predicting properties averaged over a large s le of structures, provide a more accessible way to transfer data-driven predictions into the lab.
Publisher: Royal Society of Chemistry (RSC)
Date: 2006
DOI: 10.1039/B513095F
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3CP51333E
Abstract: The use of carbon nanostructures to capture and store waste carbon, such as methane and carbon dioxide, is intrinsically attractive, particularly if the same molecules can be subsequently used as synthetic precursors. However, to facilitate adsorption of these highly stable species high pressures are required, and fragile carbon-based nanostructures may not survive. By combining electronic structure simulations and ab initio thermodynamics, we have investigated the thermochemical conditions required to adsorb CH, CH2, CO and CO2 on diamond nanoparticles, which can withstand higher temperatures and pressures than alternative carbon-based nanostructures. We find that, while CO2 must be over-saturated to facilitate stable adsorption (with high efficiency), the strength of the resultant C-O bonds means that desorption will not occur spontaneously when atmospheric pressure is resumed.
Publisher: American Chemical Society (ACS)
Date: 25-08-2023
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3GC42540A
Abstract: Progressive restrictions on the use of toxic chromate-based corrosion inhibitors present serious technical challenges.
Publisher: Informa UK Limited
Date: 04-2011
Publisher: American Chemical Society (ACS)
Date: 10-11-2007
DOI: 10.1021/JP0761766
Publisher: AIP Publishing
Date: 07-03-2008
DOI: 10.1063/1.2841366
Abstract: One of the most exciting recent developments in nanoscience was the discovery of graphene (single sheets of carbon atoms, a two-dimensional “(2D) crystal”) and the subsequent discovery of the fascinating properties of this new material, e.g., electrons behaving as massless relativistic particles and an anomalous quantum Hall effect [A. K. Geim and K. S. Novoselov, Nat. Mater. 6, 183 (2007)]. It is also surprising that large sheets of graphene exist as it was widely believed that 2D crystals are unstable. Furthermore, because of the stability of folded graphene sheets, i.e., carbon nanotubes (CNTs), a fascinating question is why does not graphene spontaneously transform into CNTs? In this paper, we explore the thermal stability of small pieces of graphene, i.e., graphene nanoflakes by ab initio quantum mechanical techniques. We find that indeed nanoflakes are stable to being heated and do not under any conditions used here transform to CNTs. They do not, however, remain strictly 2D as at finite temperatures, they undergo extensive vibrational motion and remain buckled if annealed and then quenched to room temperature.
Publisher: AIP Publishing
Date: 28-02-2003
DOI: 10.1063/1.1545450
Abstract: Over the past 15 years, a number of studies have reported findings comparing the relative stability of diamond and graphite, at the nanoscale. In light of more recent experimental and theoretical results concerning the transformation of nanodiamonds into carbon-onions, it is considered important to extend this body of work to included fullerenes. Presented here is a study of the phase stability of carbon nanoparticles, with particular attention given to the relative stability of nanodiamonds and fullerenes. The structural energies have been calculated using density functional theory within the generalized gradient approximation using the Vienna ab initio simulation package, and used to determine the standard heat of formation for respective carbon phases as a function of the number of carbon atoms. Our results show that in contrast to previously reported studies, nanodiamond is not necessarily the stable phase a the nanoscale, but instead occupies a “window” of stability between ∼1.9 and ∼5.2 nm.
Publisher: Elsevier BV
Date: 03-2021
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3CP44491K
Abstract: Graphene nano-flakes and quantum dots have considerable potential as components for nanodevices, since the finite in-plane dimension and additional edge and corner states provide potential for band gap engineering. However, like semi-infinite graphene membranes, they may contain different configurations of vacancy point defects that may be difficult to predict or control. In this paper we use density functional tight binding simulations to explore the impact of different geometric configurations of vacancies in unterminated (radical), mono-hydride and di-hydride terminated nano-flakes with zigzag or armchair edges. The results reveal that the planar structure is more uniformly preserved (with less distortion) when vacancies are located near the edges and corners, due to the combined effect of vacancy-edge-corner reconstructions, and passivating the circumference reduces the scattering of the band gap, but not the scattering of the energy of the Fermi level. In general, and regardless of the possible application, the use of zigzag-edged nano-flakes with stable edge/corner passivation is desirable to ensure reliability, and reduce the impact of an unknown number and configurations of vacancies.
Publisher: AIP Publishing
Date: 07-2020
DOI: 10.1063/5.0009129
Abstract: Computer simulations and machine learning provide complementary ways of identifying structure roperty relationships that are typically targeting toward predicting the ideal singular structure to maximize the performance in a given application. This can be inconsistent with experimental observations that measure the collective properties of entire s les of structures that contain distributions or mixture of structures, even when synthesized and processed with care. Metallic nanoparticle catalysts are an important ex le. In this study, we have used a multi-stage machine learning workflow to identify the correct structure roperty relationships of Pt nanoparticles relevant to oxygen reduction, hydrogen oxidation, and hydrogen evolution reactions. By including classification prior to regression, we identified two distinct classes of nanoparticles and subsequently generated the class-specific models based on experimentally relevant criteria that are consistent with observations. These multi-structure/multi-property relationships, predicting properties averaged over a large s le of structures, provide a more accessible way to transfer data-driven predictions into the lab.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5CP04521E
Abstract: The special structure of the zinc blende ZnO surface (211) results in its polarity, high energy and stabilized surface defects.
Publisher: Oxford University Press (OUP)
Date: 09-10-2019
DOI: 10.1002/BJS.11326
Abstract: Ileus is common after elective colorectal surgery, and is associated with increased adverse events and prolonged hospital stay. The aim was to assess the role of non-steroidal anti-inflammatory drugs (NSAIDs) for reducing ileus after surgery. A prospective multicentre cohort study was delivered by an international, student- and trainee-led collaborative group. Adult patients undergoing elective colorectal resection between January and April 2018 were included. The primary outcome was time to gastrointestinal recovery, measured using a composite measure of bowel function and tolerance to oral intake. The impact of NSAIDs was explored using Cox regression analyses, including the results of a centre-specific survey of compliance to enhanced recovery principles. Secondary safety outcomes included anastomotic leak rate and acute kidney injury. A total of 4164 patients were included, with a median age of 68 (i.q.r. 57–75) years (54·9 per cent men). Some 1153 (27·7 per cent) received NSAIDs on postoperative days 1–3, of whom 1061 (92·0 per cent) received non-selective cyclo-oxygenase inhibitors. After adjustment for baseline differences, the mean time to gastrointestinal recovery did not differ significantly between patients who received NSAIDs and those who did not (4·6 versus 4·8 days hazard ratio 1·04, 95 per cent c.i. 0·96 to 1·12 P = 0·360). There were no significant differences in anastomotic leak rate (5·4 versus 4·6 per cent P = 0·349) or acute kidney injury (14·3 versus 13·8 per cent P = 0·666) between the groups. Significantly fewer patients receiving NSAIDs required strong opioid analgesia (35·3 versus 56·7 per cent P & 0·001). NSAIDs did not reduce the time for gastrointestinal recovery after colorectal surgery, but they were safe and associated with reduced postoperative opioid requirement.
Publisher: Wiley
Date: 02-03-2023
DOI: 10.1002/JOC.8047
Abstract: The stable oxygen isotope composition of precipitation (δ 18 O p ) in southern China is considered as a valuable proxy of climatic conditions. However, their interpretations have been controversial. In this study, based on the observed and simulated data (isoGSM2) on oxygen isotope composition of precipitation, the linkage between summer precipitation ( P ) and δ 18 O p in the Dongting Lake basin and their possible influencing factors were investigated. The results indicate that the interannual variation of summer δ 18 O p is consistent with that of annual δ 18 O p . They both show a significantly negative correlation with the summer P , suggesting that the stable isotope composition in precipitation may be considered as a proxy of summer precipitation in the Dongting Lake basin. Statistically, the amount effect and circulation effect are significant in the isotope composition of precipitation in the basin. Based on either the observed data in Changsha or the simulated data for the basin, the local amount effect appears more important than large‐scale circulation for δ 18 O p during extreme summers. These results can potentially improve the reconstruction of paleoclimate in the East Asian monsoon region. Further study is needed to determine the contribution of local and large‐scale factors to the oxygen isotope composition of precipitation and to quantify the integral rainout along the moisture transporting paths.
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9NR03940F
Abstract: Visualization can be a useful precursor to quantitative machine learning methods for uncovering structure roperty relationships.
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7NR03472E
Abstract: Post-processing of silver nanoparticle s les to restrict the size and shape distributions can improve performance, but does not need to eliminate all structural ersity.
Publisher: Springer US
Date: 2010
Publisher: American Chemical Society (ACS)
Date: 15-04-2014
DOI: 10.1021/JP5018168
Publisher: American Chemical Society (ACS)
Date: 11-2013
DOI: 10.1021/CG401397Y
Publisher: Springer International Publishing
Date: 2022
Publisher: IOP Publishing
Date: 18-09-2018
Publisher: IOP Publishing
Date: 27-07-2020
Publisher: Elsevier BV
Date: 2021
Publisher: American Chemical Society (ACS)
Date: 14-01-2011
DOI: 10.1021/CS100025Y
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C6NR08315C
Abstract: Coating the surfaces of inorganic nanoparticles with polyethylene glycol (PEG) is an important step in the development of many nanoparticle-based drug delivery systems. The efficiency with which drug molecules can be loaded on to nanoparticle surfaces is contingent on the concentration, distribution and stability of the PEG coating. In this study the distribution and relative stability of PEG on diamond nanoparticles is predicted, for clean and passivated surface structures, in 3D. This is an ideal exemplar, since PEGylated diamond nanoparticles are already being trialed as carriers for doxorubicin (DOX). The results show that PEGylation is favorable near the {100} facets regardless of surface reconstructions or pre-treatment, but pre-treatment is required to increase the probability of stable and homogeneous PEGylation on other facets.
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C1CY00238D
Publisher: MDPI AG
Date: 15-11-2021
Abstract: Radiotherapy plays an important role of managing head and neck squamous cell carcinoma (HNSCC). Concurrent radiotherapy with radiosensitizing cisplastin chemotherapy is the standard of care (SOC) for non-operable locally advanced HNSCC. Cetuximab, a monoclonal antibody of epidermal growth factor receptor, was the most extensively studied targeted therapy as a chemo-sparing agent that was used concurrently with radiotherapy. Immunotherapy is used in the treatment of metastatic HNSCC. There is evidence to support the synergistic effect when combining radiotherapy with immunotherapy to potentiate anti-tumor immune response. There has been increasing interest to incorporate immune checkpoint inhibitor (ICI) with radiotherapy in the curative setting for HNSCC. In this review, we discuss the latest evidence that supports concurrent radiotherapy with cisplatin which remains the SOC for locally advanced HNSCC (LA-HNSCC). Cetuximab is suitable for patients who are not fit for cisplatin. We then summarize the clinical trials that incorporate ICI with radiotherapy for LA-HNSCC in concurrent, neoadjuvant, and adjuvant settings. We also discuss the potential of combining immunotherapy with radiotherapy as a treatment de-escalating strategy in HPV-associated oropharyngeal carcinoma. Finally, the pre-clinical and clinical evidence of the abscopal effect when combining stereotactic body radiotherapy with ICIs is presented.
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2CP40862G
Abstract: The remarkable properties of carbon nanotubes have made them the preferred candidate for a number of exciting new technologies, and the intense focus of an enormous volume of scientific research. Much of this work is performed under highly idealized conditions, and less attention has typically been given to understanding what happens when carbon nanotubes are exposed to more realistic conditions, such as those typical in everyday devices. One of the most important aspects of this real world exposure will be the interaction of carbon nanotubes with our atmosphere. Adsorption of air will impact the stability of the carbon nanotubes, and may have undesirable consequences for the fundamental properties and the reliability of the device. Since this is a very challenging problem to address using experimental methods, it is often appropriate to begin by using theory and simulation. Presented here is a general analytical model for describing the thermodynamic stability of carbon nanotubes in the presence of gas adsorbates. This model is used to examine the stability of nanotubes in air, as a function of the relative humidity, but is equally applicable to any gaseous environments given suitable input parameters.
Publisher: IOP Publishing
Date: 18-12-2016
DOI: 10.1088/0953-8984/28/2/023002
Abstract: Although there have been significant advances in the fields of theoretical condensed matter and computational physics, when confronted with the complexity and ersity of nanoparticles available in conventional laboratories a number of modeling challenges remain. These challenges are generally shared among application domains, but the impacts of the limitations and approximations we make to overcome them (or circumvent them) can be more significant one area than another. In the case of nanoparticles for drug delivery applications some immediate challenges include the incompatibility of length-scales, our ability to model weak interactions and solvation, the complexity of the thermochemical environment surrounding the nanoparticles, and the role of polydispersivity in determining properties and performance. Some of these challenges can be met with existing technologies, others with emerging technologies including the data-driven sciences some others require new methods to be developed. In this article we will briefly review some simple methods and techniques that can be applied to these (and other) challenges, and demonstrate some results using nanodiamond-based drug delivery platforms as an exemplar.
Publisher: American Chemical Society (ACS)
Date: 02-06-2009
DOI: 10.1021/NN900220K
Abstract: The development of the next generation of nanotechnologies requires precise control of the size, shape, and structure of in idual components in a variety of chemical and engineering environments. This includes synthesis, storage, operational environments and, since these products will ultimately be discarded, their interaction with natural ecosystems. Much of the important information that determines these properties is contained within nanoscale phase diagrams, but quantitative phase maps that include surface effects and critical diameter (along with temperature and pressure) remain elusive. Here we present the first quantitative equilibrium phase map for gold nanoparticles together with experimental verification, based on relativistic ab initio thermodynamics and in situ high-resolution electron microscopy at elevated temperatures.
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9NR05912A
Abstract: The combination of computational chemistry and computational materials science with machine learning and artificial intelligence provides a powerful way of relating structural features of nanomaterials with functional properties.
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2NR30324H
Abstract: Fluorescent metal nanoparticles have attracted great interest in recent years for their unique properties and potential applications. Their optical behaviour depends not only on size but also on shape, and will only be useful if the morphology is stable. In this work, we produce stable size-selected gold nanorods (aspect ratio 1-2) using a size-selected cluster source and correlate their luminescence behaviour with the particle shape. Thermodynamic modelling is used to predict the preferred aspect ratio of 1.5, in agreement with the observations, and confirms that the double-icosahedron observed in experiments is significantly lower in energy than the alternatives. Using these s les a fluorescence lifetime imaging microscopy study observed two photon luminescence from nanoparticle arrays and a fast decay process (<100 ps luminescence lifetime), which are similar to those found from ligand stabilized gold nanorods under the same measurement conditions, indicating that a surface plasmon enhanced two-photon excitation process is still active at these small sizes. By further reducing the nanoparticle size, this approach has the potential to investigate size-dependent luminescence behaviour at smaller sizes than has been possible before.
Publisher: American Scientific Publishers
Date: 06-2005
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C6NR07102C
Abstract: The magnitude and complexity of the structural and functional data available on nanomaterials requires data analytics, statistical analysis and information technology to drive discovery. We demonstrate that multivariate statistical analysis can recognise the sets of truly significant nanostructures and their most relevant properties in heterogeneous ensembles with different probability distributions. The prototypical and archetypal nanostructures of five virtual ensembles of Si quantum dots (SiQDs) with Boltzmann, frequency, normal, Poisson and random distributions are identified using clustering and archetypal analysis, where we find that their ersity is defined by size and shape, regardless of the type of distribution. At the complex hull of the SiQD ensembles, simple configuration archetypes can efficiently describe a large number of SiQDs, whereas more complex shapes are needed to represent the average ordering of the ensembles. This approach provides a route towards the characterisation of computationally intractable virtual nanomaterial spaces, which can convert big data into smart data, and significantly reduce the workload to simulate experimentally relevant virtual s les.
Publisher: American Chemical Society (ACS)
Date: 28-07-2010
DOI: 10.1021/NL101642F
Abstract: Accurate understanding of the structure of active sites is fundamentally important in predicting catalytic properties of heterogeneous nanocatalysts. We present an accurate determination of both experimental and theoretical atomic structures of surface monatomic steps on industrial platinum nanoparticles. This comparison reveals that the edges of nanoparticles can significantly alter the atomic positions of monatomic steps in their proximity, which can lead to substantial deviations in the catalytic properties compared with the extended surfaces.
Publisher: Elsevier BV
Date: 02-2017
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2CY20017A
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C1JM10381D
Publisher: AIP Publishing
Date: 02-04-2007
DOI: 10.1063/1.2720715
Abstract: The authors show that, during a steady-state vapor phase growth of ZnO nanomaterials, indium doping causes the structural change from usual [0001]-axial short nanowires to [112¯0]-axial nanobelts of much larger aspect ratio. They used an analytical thermodynamic model based on geometric summation of the Gibbs free energy to predict the dimension dependence of the nanowires and nanobelts for both pure and In-doped ZnO. The calculation result agrees with the experiment observation that in situ indium doping influences the nucleation and supports the dominating growth of a-axial nanobelts over c-axial nanowires.
Publisher: No publisher found
Date: 2014
Publisher: Elsevier BV
Date: 04-2020
Publisher: Elsevier BV
Date: 05-2020
Publisher: Cambridge University Press (CUP)
Date: 2019
DOI: 10.1017/S0950268819000773
Abstract: Incidence of human yersiniosis in New Zealand has increased between 2013 and 2017. For surveillance and outbreak investigations it is essential that an appropriate level of discrimination between pathogenic Yersinia enterocolitica isolates is provided, in order to support epidemiological linking of connected cases. Subtyping of 227 Y. enterocolitica isolates was performed using a range of different typing methods, including biotyping, serotyping and seven loci multiple-locus variable-number tandem-repeat analysis (MLVA). In addition, core genome single-nucleotide polymorphism (core SNP) analysis and multi-locus sequence typing were performed on a subset of 69 isolates. Sixty-seven different MLVA types were identified. One MLVA profile was associated with an outbreak in the Bay of Plenty region, supported by epidemiological data. Core SNP analysis showed that all the outbreak-related isolates clustered together. The subtyping and epidemiological evidence suggests that the outbreak of yersiniosis in the Bay of Plenty region between October and December 2016 could be attributed to a point source. However, subtyping results further suggest that the same clone was isolated from several regions between August 2016 and March 2017. Core SNP analysis and MLVA typing failed to differentiate between Y. enterocolitica biotype 2 and biotype 3. For this reason, we propose that these biotypes should be reported as a single type namely: Y. enterocolitica biotype 2/3 and that the serotype should be prioritised as an indicator of prevalence.
Publisher: Springer Science and Business Media LLC
Date: 19-09-2018
Publisher: American Chemical Society (ACS)
Date: 11-11-2015
Publisher: Informa UK Limited
Date: 02-04-2018
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D0NH00637H
Abstract: Scientific intuition can help anticipate the outcome of experiments, but machine learning based on data does not always support these assumptions. A direct comparison of human intelligence (HI) and AI suggests domain knowledge is not always enough.
Publisher: American Chemical Society (ACS)
Date: 10-09-2014
DOI: 10.1021/JP506135M
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9NH00060G
Abstract: Using a combination of electronic structure simulations and machine learning we have shown that the characteristic negative electron affinity (NEA) of hydrogenated diamond nanoparticles exhibits a class-dependent structure roperty relationship.
Publisher: Informa UK Limited
Date: 2003
Publisher: Springer Science and Business Media LLC
Date: 24-07-2013
Publisher: American Chemical Society (ACS)
Date: 29-11-2018
Publisher: Royal Society of Chemistry (RSC)
Date: 2007
DOI: 10.1039/B704798C
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C2TA00523A
Publisher: IOP Publishing
Date: 18-09-2018
Publisher: Wiley
Date: 06-09-2020
Abstract: The binding energy of small molecules on two‐dimensional (2D) single atom catalysts influences their reaction efficiency and suitability for different applications. In this study, the binding energy on single metal atoms to N‐doped graphene defects was predicted using random forest regression based on approximately 1700 previously generated density functional theory simulations of catalytic reactions. Three different structural feature groups containing hundreds of in idual structural features were created and used to characterise the active sites. This approach was found to be accurate and reliable using either fully relaxed output structures or pre‐simulation input structures, with coefficients of determination of =0.952 and =0.865, respectively. The ability to predict optimal 2D‐catalysts before undertaking expensive quantum chemical calculations is an attractive basis for future research, and could be extended to other 2D‐materials.
Publisher: American Chemical Society (ACS)
Date: 27-08-2008
DOI: 10.1021/JP805194U
Publisher: No publisher found
Date: 2017
Publisher: American Chemical Society (ACS)
Date: 25-11-2015
Abstract: High-throughput (HT) computational characterization of nanomaterials is poised to accelerate novel material breakthroughs. The number of possible nanomaterials is increasing exponentially along with their complexity, and so statistical and information technology will play a fundamental role in rationalizing nanomaterials HT data. We demonstrate that multivariate statistical analysis of heterogeneous ensembles can identify the truly significant nanoparticles and their most relevant properties. Virtual s les of diamond nanoparticles and graphene nanoflakes are characterized using clustering and archetypal analysis, where we find that saturated particles are defined by their geometry, while nonsaturated nanoparticles are defined by their carbon chemistry. At the complex hull of the nanostructure spaces, a combination of complex archetypes can efficiency describe a large number of members of the ensembles, whereas the regular shapes that are typically assumed to be representative can only describe a small set of the most regular morphologies. This approach provides a route toward the characterization of computationally intractable virtual nanomaterial spaces, which can aid nanomaterials discovery in the foreseen big data scenario.
Publisher: Cambridge University Press (CUP)
Date: 12-1998
DOI: 10.1017/S1357729800032859
Abstract: A selection index which incorporates estimated breeding values of traits recorded in the United Kingdom pedigree beef cattle breeds is described. The breeding objective is made up of commercial carcass, calving difficulty and gestation length traits. Economic values for these breeding objective traits are summarized from related studies, while partial genetic regression estimates of breeding objective traits on recorded traits are derived mainly from the literature. The selection index is described in terms of the reduction in expected genetic response from selection on the index when in idual recorded traits are omitted and the expected genetic responses in breeding objective traits with selection on the index under the assumption of mass selection. Failure to record all calving traits (birth weight, calving difficulty and gestation length) resulted in a reduction in expected economic response to selection of 8% from the situation where both calving traits and production traits (400-day weight, ultrasonic fat and muscle depths, and muscling score) are recorded. With a few stated exceptions, the index is relatively robust to errors in estimates of in idual parameters. It is suggested that the total index be used to assist commercial bull and semen buyers in their selection decisions but that two sub-indices for calving and production traits also be published to allow buyers to adjust emphasis on the two groups of traits depending on their in idual production circumstances.
Publisher: American Chemical Society (ACS)
Date: 11-12-2015
Abstract: The intrinsic relationships between nanoscale features and electronic properties of nanomaterials remain poorly investigated. In this work, electronic properties of 622 computationally optimized graphene structures were mapped to their structures using partial-least-squares regression and radial distributions function (RDF) scores. Quantitative structure-property relationship (QSPR) models were calibrated with 70% of a virtual data set of 622 passivated and nonpassivated graphenes, and we predicted the properties of the remaining 30% of the structures. The analysis of the optimum QSPR models revealed that the most relevant RDF scores appear at interatomic distances in the range of 2.0 to 10.0 Å for the energy of the Fermi level and the electron affinity, while the electronic band gap and the ionization potential correlate to RDF scores in a wider range from 3.0 to 30.0 Å. The predictions were more accurate for the energy of the Fermi level and the ionization potential, with more than 83% of explained data variance, while the electron affinity exhibits a value of ∼80% and the energy of the band gap a lower 70%. QSPR models have tremendous potential to rapidly identify hypothetical nanomaterials with desired electronic properties that could be experimentally prepared in the near future.
Publisher: American Chemical Society (ACS)
Date: 25-08-2009
DOI: 10.1021/NL9017379
Abstract: Fluorescent defects in noncytotoxic diamond nanoparticles are candidates for qubits in quantum computing, optical labels in biomedical imaging, and sensors in magnetometry. For each application these defects need to be optically and thermodynamically stable and included in in idual particles at suitable concentrations (singly or in large numbers). In this Letter, we combine simulations, theory, and experiment to provide the first comprehensive and generic prediction of the size, temperature, and nitrogen-concentration-dependent stability of optically active N-V defects in nanodiamonds.
Publisher: Wiley
Date: 12-02-2019
DOI: 10.1002/CNCR.31983
Publisher: Elsevier BV
Date: 07-2003
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C1NR11049G
Abstract: Ideally, graphene may be regarded as a strictly 2-D structure. However, as it exists in a 3-D world, perturbations often distort this ideal 2-D structure. Under a variety of conditions graphene has been shown to develop ripples, which may have undesirable consequences for a variety of properties of graphene, such as electron transport. In addition to this, it has been speculated that ripples may be an intrinsic property of graphene, and it has also been suggested that unlocking the secrets of these ripples could be useful in the search for (an understanding of) the elusive Higgs boson. However, ripples in graphene can only be avoided, or utilized, if they can be reproducibly detected. Here we explore the most fundamental aspect of these ripples, that is, the effect of a static ripple structure on various properties of large graphene nanoflakes. We find that the mechanical, thermodynamic and electronic properties are unaltered by this fundamental rippling, but this spontaneous symmetry breaking induces a significant change in the structure of the wavefunction. This profound effect occurs only at the most basic level, but it should be, in principle, experimentally observable.
Publisher: IOP Publishing
Date: 25-02-2009
DOI: 10.1088/0957-4484/20/11/115702
Abstract: Previous experimental studies have indicated that the controlled formation of anisotropic pyrite nanoparticles, such as nanorods or nanowires, is dependent on the right combination of solution chemistry and temperature. Similarly, the morphology of the in idual nanocrystals during intracellular biomineralization of single nanocrystals has been attributed to the local environmental conditions, as well as the species of the micro-organism. Although there are obvious similarities, using the lessons from biomineralization to assist the laboratory synthesis of anisotropic pyrite nanostructures, and in the anticipation of environmental stability, requires a more detailed understanding of the role played by in idual environmental parameters. In the present study we use a multi-scale thermodynamic model, combined with parameters obtained from first principles calculations, to investigate the formation and stability of pyrite nanorods as a function of temperature and chemical environment. The results of our systematic modeling of parameter space predict that the morphology of pyrite nanorods grown in the laboratory, or associated with biomineralization, is more likely to be a function of surface ligands and the biology of the organisms than a function of simpler environmental parameters such as temperature, pressure, concentration of sulfur and adsorption of water.
Publisher: American Chemical Society (ACS)
Date: 09-01-2023
Publisher: Informa UK Limited
Date: 11-07-2020
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/C0JM01436B
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3MH00157A
Publisher: American Physical Society (APS)
Date: 03-12-2004
Publisher: Informa UK Limited
Date: 2003
Publisher: Springer Science and Business Media LLC
Date: 07-2006
Publisher: Royal Society of Chemistry (RSC)
Date: 2009
DOI: 10.1039/B819214F
Publisher: AIP Publishing
Date: 20-02-2004
DOI: 10.1063/1.1643354
Abstract: Since their discovery in 1990, the study of sp2 bonded carbon nanotubes has grown into a field of research in it’s own right however the development of the sp3 analog, diamond nanowires, has been slow. A number of theoretical models have been proposed to compare the relative stability of diamond and graphite at the nanoscale and more recently, to compare nanodiamonds and fullerenes. Presented here is a study of the phase stability of nanocarbon in one-dimension. The structural energies of carbon nanotubes and diamond nanowires have been calculated using density functional theory within the generalized gradient approximation, and used to determine the atomic heat of formation as a function of size.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5CY00123D
Abstract: While reducing the size, and restricting shape of nanocatalysts can improve performance, monodispersed s les are not necessarily ideal.
Publisher: Wiley
Date: 05-2020
DOI: 10.1002/MP.13942
Publisher: AIP Publishing
Date: 18-08-2004
DOI: 10.1063/1.1775770
Abstract: A thermodynamic model describing relative stability of different shapes for nanoparticles as a function of their size was developed for arbitrary crystalline solids and applied to group IV semiconductors. The model makes use of various surface, edge and corner energies, and takes into account surface tension. Approximations and importance of each term of the model were analyzed. The predictions for clean and hydrogenated diamond nanoparticles are compared to explicitly calculated density functional results. It is shown that diamond nanocrystal morphology is markedly different from silicon and germanium.
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8CP06649C
Abstract: The crystalline structural stability and threshold of amorphisation of carbon, silicon and silicon carbide is investigated via vacancy removal and Monte Carlo annealing simulations.
Publisher: American Chemical Society (ACS)
Date: 14-08-2008
DOI: 10.1021/CM8001892
Publisher: Springer International Publishing
Date: 2018
Publisher: American Chemical Society (ACS)
Date: 17-10-2008
DOI: 10.1021/JP806944Q
Abstract: We report studies aimed at unraveling the complicated structure of the CCl 2 A (1)B 1 <-- X (1)A 1 system. We have remeasured the fluorescence excitation spectrum from approximately 17,500 to 24,000 cm (-1) and report the term energies and A rotational constants of many new bands for both major isotopologues (C (35)Cl 2, C (35)Cl (37)Cl). We fit the observed term energies to a polyad effective Hamiltonian model and demonstrate that a single resonance term accounts for much of the observed mixing, which begins approximately 1300 cm (-1) above the vibrationless level of the A (1)B 1 state. The derived A (1)B 1 vibrational parameters are in excellent agreement with ab initio predictions, and the mixing coefficients deduced from the polyad model fit are in close agreement with those derived from direct fits of single vibronic level (SVL) emission intensities. The approach to linearity and thus the Renner-Teller (RT) intersection is probed through the energy dependence of the A rotational constant and fluorescence lifetime measurements, which indicate a barrier height above the vibrationless level of the X (1)A 1 state of approximately 23,000-23,500 cm (-1), in excellent agreement with ab initio theory.
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1NR02258J
Abstract: Nanoscience is multi-disciplinary and nanoparticles can be described in different ways. Using pattern recognition we show that choice of descriptors can influence the amount of detail from machine learning, but not necessarily the underlying trends.
Publisher: Royal Society of Chemistry (RSC)
Date: 27-08-2014
DOI: 10.1039/C4TA03414G
Publisher: American Chemical Society (ACS)
Date: 13-03-2009
DOI: 10.1021/JP809377S
Publisher: No publisher found
Date: 2017
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C0NR00883D
Abstract: A reliable explanation for the underlying mechanism responsible for the persistent aggregation and self-assembly of colloidal 5 nm diamond nanoparticles is critical to the development of nanodiamond-based technologies. Although a number of mechanisms have been proposed, validation has been hindered by the inherent difficulty associated with the identification and characterisation of the inter-particle interfaces. In this paper we present results of high resolution aberration corrected electron microscopy and complementary computer simulations to explicate the features involved, and confirm the electrostatic interaction mechanism as the most probable cause for the formation of agglutinates and agglomerates of primary particles.
Publisher: Elsevier BV
Date: 2019
Publisher: Springer Science and Business Media LLC
Date: 07-08-2018
DOI: 10.1007/S00259-018-4112-2
Abstract: To evaluate the impact of positron emission tomography (PET) staging on overall survival (OS) and progression-free survival (PFS) in patients with early-stage (stages I and II) follicular lymphoma (ESFL) treated with radiation therapy alone. Eighty-five patients with ESFL treated with curative-intent radiation therapy (RT) between December 2000 and May 2011 were identified. Of those, 13 who had no PET staging and 25 who received additional systemic therapy were excluded from the analysis. Thus, we analyzed 47 patients with PET-staged ESFL treated with definitive radiation therapy alone (dose > 23Gy). Tumour features, pre-treatment computed tomography (CT) and PET stage, dose fractionation, and radiation therapy field extent were recorded. The Kaplan-Meier method was used to estimate the OS and PFS. Patterns of failure were assessed as cumulative incidences assuming competing risks. Median age was 57 years (range 24-83) 43% were females. Most were PET stage 1 (76.6%). Median maximum nodal diameter was 3 cm. Median pre-treatment lactate dehydrogenase (LDH) was 327.5 (range 123-607, upper normal limit = 220). Twenty-six patients (55.3%) had infra-diaphragmatic disease. All received 30-36Gy in 15-24 fractions, with 59.6% treated with involved-field radiation therapy (IFRT) techniques. There was no significant difference in PFS between CT stage I and stage II (HR 1.30 95% CI [0.25-6.72], p = 0.75) with a 5-year PFS of 77% and 78% respectively. However, stage I on PET staging had a significantly better PFS than stage II (HR 4.66 95% CI [1.15-18.8], p = 0.038), with 5-year PFS of 84% and 60% respectively. Ten patients had recurrent disease, with distant disease being the first site of failure in seven patients. Seven-year OS was 91% (95% CI 79-100) for the whole cohort. FDG-PET should be considered an essential element in the evaluation of patients with ESFL being considered for RT.
Publisher: American Chemical Society (ACS)
Date: 03-11-2004
DOI: 10.1021/JP0472459
Publisher: Royal Society of Chemistry (RSC)
Date: 2008
DOI: 10.1039/B809188A
Publisher: Wiley
Date: 25-07-2017
DOI: 10.1002/HED.24872
Abstract: The purpose of this study was to present our experience with retropharyngeal node reirradiation using highly conformal radiotherapy (RT). A retrospective screen of 2504 consecutively irradiated patients with head and neck malignancies between 2005 and 2015 identified 19 patients who underwent reirradiation for retropharyngeal node metastasis. Clinical and toxicity outcomes were assessed in these patients. Thirteen patients (68%) had squamous cell carcinoma. Eleven patients (58%) received conventionally fractionated intensity-modulated radiotherapy (IMRT) or proton therapy, and 8 patients (42%) received single-fractionated or hypofractionated stereotactic RT. Fourteen patients (74%) received chemotherapy. Median follow-up was 14.7 months. The 1-year local control, locoregional control, overall survival, and progression-free survival rates were 100%, 94%, 92%, and 92%, respectively. Three patients (16%) experienced acute grade 3 toxicity and occurred in those treated with IMRT. There was no late grade ≥3 toxicity. Retropharyngeal node reirradiation with conformal therapy is well tolerated and associated with excellent short-term disease control.
Publisher: Elsevier BV
Date: 06-2019
Publisher: Wiley
Date: 09-02-2009
Publisher: Elsevier BV
Date: 02-2006
Publisher: Wiley
Date: 18-04-2005
Publisher: Springer Science and Business Media LLC
Date: 22-04-2021
DOI: 10.1186/S12885-021-08195-8
Abstract: Radiotherapy, along with laser surgery, is considered a standard treatment option for patients with early glottic squamous cell cancer (SCC). Historically, patients have received complete larynx radiotherapy (CL-RT) due to fear of swallowing and respiratory laryngeal motion and this remains the standard approach in many academic institutions. Local control (LC) rates with CL-RT have been excellent, however this treatment can carry significant toxicities include adverse voice and swallowing outcomes, along with increased long-term risk of cerebrovascular morbidity. A recent retrospective study reported improved voice quality and similar local control outcomes with focused vocal cord radiotherapy (VC-RT) compared to CL-RT. There is currently no prospective evidence on the safety of VC-RT. The primary objective of this Bayesian Phase II trial is to compare the LC of VC-RT to that of CL-RT in patients with T1N0 glottic SCC. One hundred and fifty-five patients with T1a-b N0 SCC of the true vocal cords that are n ot candidate or declined laser surgery, will be randomized in a 1:3 ratio the control arm (CL-RT) and the experimental arm (VC-RT). Randomisation will be stratified by tumor stage (T1a/T1b) and by site (each site will be allowed to select one preferred radiation dose regimen, to be used in both arms). CL-RT volumes will correspond to the conventional RT volumes, with the planning target volume extending from the top of thyroid cartilage lamina superiorly to the bottom of the cricoid inferiorly. VC-RT volumes will include the involved vocal cord(s) and a margin accounting for respiration and set-up uncertainty. The primary endpoint will be LC at 2-years, while secondary endpoints will include patient-reported outcomes (voice impairment, dysphagia and symptom burden), acute and late toxicity radiation-induced toxicity, overall survival, progression free survival, as well as an optional component of acoustic and objective measures of voice analysis using the Consensus Auditory-Perceptual Evaluation of Voice. This study would constitute the first prospective evidence on the efficacy and safety of VC-RT in early glottic cancer. If positive, this study would result in the adoption of VC-RT as standard approach in early glottic cancer. ClinicalTrials.gov Identifier: NCT03759431 Registration date: November 30, 2018
Publisher: Informa UK Limited
Date: 03-04-2019
DOI: 10.1080/10428194.2019.1597081
Abstract: Controversy exists regarding the optimal management of limited stage grade 3 follicular lymphoma (FL3). We assessed the treatment outcomes of 190 consecutive patients with stage I-II FL. Fifty two patients had FL3 disease, in whom the median age was 55 years. At a median follow-up of 65 months, 5-year progression-free survival (PFS) and overall survival (OS) rates were 76.6% and 87.6%, respectively. Patients receiving systemic therapy followed by radiation therapy (RT) had a significantly better PFS (
Publisher: Elsevier BV
Date: 09-2022
DOI: 10.1016/J.CHEMOSPHERE.2022.135033
Abstract: The economic and social future of nanotechnology depends on our ability and manufacture nanomaterials that avoid potential toxicity, by identifying them before they are made, used and released into the environment. Safety-by-design is a framework for including these issues at an early stage of the development process, but balancing multiple nanoparticle properties and selection criteria remains challenging. Based on a synthetic data set of over 19,000 possible sunscreen product specifications, we have used multi-target machine learning to predict the corresponding size, shape, concentration and polytype of titania nanoparticle additives. The study considers the optical properties responsible for the sun protection factor and product transparency, including the extinction coefficients for ultra violet and visible light, and the potential for toxicity due to the generation of reactive oxygen species from the photocatalytically active facets of both anatase and rutile nanoparticles, as a function of the size and shape. We predict a number of conventional forward structure roperty and property roduct relationships, but show that a direct structure roduct relationship provides superior performance when predicting multiple properties or product specifications simultaneously. These models are then inverted, re-optimized and re-trained to provide focused, high performing inverse design models that do not require additional optimization, and are capable of identifying nanoparticle configurations outside of the training set. The ability to directly predict suitable nanoparticle structures that conform to prerequisite sun protection, transparently and potential toxicity thresholds represents a new approach to safety-by-design that can be applied to other products and materials where multiple design criteria must be met at the same time.
Publisher: American Chemical Society (ACS)
Date: 08-03-2020
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5NR06759F
Abstract: Like many of the useful nanomaterials being produced on the industrial scale, the surface of diamond nanoparticles includes a complicated mixture of various atomic and molecular adsorbates, attaching to the facets following synthesis. Some of these adsorbates may be functional, and adsorption is encouraged to promote applications in biotechnology and nanomedicine, but others are purely adventurous and must be removed prior to use. In order to devise more effective treatments it is advantageous to know the relative strength of the interactions of the adsorbates with the surface, and ideally how abundant they are likely to be under different conditions. In this paper we use a series of explicit electronic structure simulations to map the distribution of small hydrocarbons, amines and thiols on a 2.9 nm diamond nanoparticle, with atomic level resolution, in 3-D. We find a clear relationship between surface reconstructions, facet orientation, and the distribution of the different adsorbates with a greater concentration expected on the (100) and (110) facets, particularly when the supersaturation in the reservoir is high. Adsorption on the (111) facets is highly unlikely, suggesting that controlled graphitization may be a useful stage in the cleaning and treatment of nanodiamonds, prior to the deliberate coating with functional adsorbates needed for drug delivery applications.
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3TC30313F
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8NR06450D
Abstract: Imperfection becomes a new design parameter if we can predict the impact of bulk and surface anisotropy on the number of active sites needed for different reactions.
Publisher: American Chemical Society (ACS)
Date: 27-07-2017
DOI: 10.1021/ACSCOMBSCI.7B00087
Abstract: Current benchmarking methods in quantum chemistry rely on databases that are built using a chemist's intuition. It is not fully understood how erse or representative these databases truly are. Multivariate statistical techniques like archetypal analysis and K-means clustering have previously been used to summarize large sets of nanoparticles however molecules are more erse and not as easily characterized by descriptors. In this work, we compare three sets of descriptors based on the one-, two-, and three-dimensional structure of a molecule. Using data from the NIST Computational Chemistry Comparison and Benchmark Database and machine learning techniques, we demonstrate the functional relationship between these structural descriptors and the electronic energy of molecules. Archetypes and prototypes found with topological or Coulomb matrix descriptors can be used to identify smaller, statistically significant test sets that better capture the ersity of chemical space. We apply this same method to find a erse subset of organic molecules to demonstrate how the methods can easily be reapplied to in idual research projects. Finally, we use our bias-free test sets to assess the performance of density functional theory and quantum Monte Carlo methods.
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/B915383G
Publisher: American Physical Society (APS)
Date: 11-12-2003
Publisher: American Chemical Society (ACS)
Date: 15-06-2012
DOI: 10.1021/AR3000184
Abstract: Under a given set of conditions, nanomaterials can crystallize into structures that are entirely inconsistent with the bulk material and may adopt a range of faceted morphologies that depend on the particle size. A size-dependent phase diagram, a graphical representation of the chemical equilibrium, offers a convenient way to describe this relationship among the size, morphology, and thermodynamic environment. Although creating such a diagram from conventional experiments is extremely challenging (and costly), theory and simulation allow us to use virtual experiments to control the temperature, pressure, size, structure and composition independently. Although the stability and morphology of gold nanoparticles has been add-ressed numerous times in recent years, a critical examination of the literature reveals a number of glaring contradictions. Typically gold nanoparticles present as multiply-twinned structures, such as icosahedra and decahedra, or faceted monocrystalline (fcc) shapes, such as truncated octahedra and cuboctahedra. All of these shapes are dominated by various fractions of {111} and {100} facets, which have different surface atom densities, electronic structure, bonding, chemical reactivities, and thermodynamic properties. Although many of the computational (and theoretical) studies agree on the energetic order of the different motifs and shapes, they do not necessarily agree with experimental observations. When discrepancies arise between experimental observations and thermodynamic modeling, they are often attributed to kinetics. But only recently could researchers analytically compare the kinetics and thermodynamics of faceted nanoparticles. In this Account, we follow a theoretical study of the size, shape, and structure of nanogold. We systematically explore why certain shapes are expected at different sizes and (more importantly) why others are actually observed. Icosahedra are only thermodynamically preferred at small sizes, but we find that they are the most frequently observed structures at larger sizes because they are kinetically stable (and coarsen more rapidly). In contrast, although the phase diagram correctly predicts that other motifs will emerge at larger sizes, it overestimates the frequency of those observations. These results suggest either a competition or collaboration between the kinetic and thermodynamic influences. We can understand this interaction between influences if we consider the change in shape and the change in size over time. We then use the outputs of the kinetic model as inputs for the thermodynamic model to plot the thermodynamic stability as a function of time. This comparison confirms that decahedra emerge through a combination of kinetics and thermodynamics, and that the fcc shapes are repressed due to an energetic penalty associated with the significant departure from the thermodynamically preferred shape. The infrequent observation of the fcc structures is governed by thermodynamics alone.
Publisher: Springer Science and Business Media LLC
Date: 04-03-2015
DOI: 10.1038/519037A
Publisher: Elsevier BV
Date: 08-2018
Publisher: CSIRO
Date: 2020
Publisher: Georg Thieme Verlag KG
Date: 31-07-2019
Abstract: Purpose The aim of this study was to evaluate outcomes of patients who received reirradiation for small skull base tumors utilizing either intensity modulated radiotherapy (IMRT), stereotactic body radiotherapy (SBRT), and proton radiotherapy (PRT). Methods Patients who received IMRT, SBRT or PRT reirradiation for recurrent or new small skull base tumors ( 60 cc) between April 2000 and July 2016 were identified. Those with 3 months follow-up were excluded. Clinical outcomes and treatment toxicity were assessed. The Kaplan–Meier method was used to estimate the local control (LC), regional control (RC), distant control (DC), progression free survival (PFS), and overall survival (OS). Results Of the 75 patients eligible, 30 (40%) received SBRT, 30 (40%) received IMRT, and 15 (20%) received PRT. The median retreatment volume was 28 cc. The median reirradiation dose was 66 Gy in 33 fractions for IMRT/PRT, and 45 Gy in 5 fractions for SBRT. The median time to reirradiation was 41 months. With a median follow-up of 24 months, the LC, RC, DC, PFS, and OS rates were 84%, 79%, 82%, 60%, and 87% at 1 year, and 75%, 72%, 80%, 49%, and 74% at 2 years. There was no difference in OS between radiation modalities. The 1- and 2-year late Grade 3 toxicity rates were 3% and 11% respectively.. Conclusions Reirradiation of small skull base tumors utilizing IMRT, PRT, or SBRT provided good local tumor control and low rates of Grade 3 late toxicity. A prospective clinical trial is needed to guide selection of radiation treatment modalities.
Publisher: No publisher found
Date: 2014
Publisher: Informa UK Limited
Date: 08-2002
Publisher: American Physical Society (APS)
Date: 08-03-2011
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2JM31249B
Publisher: IOP Publishing
Date: 31-08-2017
Abstract: Computational screening is key to understanding structure-function relationships at the nanoscale but the high computational cost of accurate electronic structure calculations remains a bottleneck for the screening of large nanomaterial libraries. In this work we propose a data-driven strategy to predict accuracy differences between different levels of theory. Machine learning (ML) models are trained with structural features of graphene nanoflakes to predict the differences between electronic properties at two levels of approximation. The ML models yield an overall accuracy of 94% and 88%, for energy of the Fermi level and the band gap, respectively. This strategy represents a successful application of established ML methods to the selection of optimum level of theory, enabling more rapid and efficient screening of nanomaterials, and is extensible to other materials and computational methods.
Publisher: Wiley
Date: 10-10-2015
DOI: 10.1002/JMRS.143
Publisher: American Chemical Society (ACS)
Date: 18-04-2019
Publisher: Elsevier BV
Date: 12-2007
Publisher: IOP Publishing
Date: 12-2022
Abstract: Property analysis and prediction is a challenging topic in fields such as chemistry, nanotechnology and materials science, and often suffers from lack of data. Federated learning (FL) is a machine learning (ML) framework that encourages privacy-preserving collaborations between data owners, and potentially overcomes the need to combine data that may contain proprietary information. Combining information from different data sets within the same domain can also produce ML models with more general insight and reduce the impact of the selection bias inherent in small, in idual studies. In this paper we propose using horizontal FL to mitigate these data limitation issues and explore the opportunity for data-driven collaboration under these constraints. We also propose FedRed, a new dimensionality reduction method for FL, that allows faster convergence and accounts for differences between in idual data sets. The FL pipeline has been tested on a collection of eight different data sets of metallic nanoparticles, and while there are expected losses compared to a combined data set that does not preserve the privacy of the collaborators, we obtained extremely good result compared to local training on in idual data sets. We conclude that FL is an effective and efficient method for the physical science domain that could hugely reduce the negative effect of insufficient data.
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5CY01205H
Abstract: Different types of surface defects are needed for specific types of catalytic reactions, and can be promoted or suppressed by varying the temperature and rates during the early stages of growth.
Publisher: Elsevier BV
Date: 03-2020
Publisher: American Scientific Publishers
Date: 02-2011
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4CP03221G
Abstract: We estimate the energies of intrinsically coupled (0001)-Zn/O faces of wurtzite ZnO using a heterojunction model.
Publisher: World Scientific Pub Co Pte Lt
Date: 20-08-2003
DOI: 10.1142/S0217979203020752
Abstract: Presented here are results of ab initio Density Functional Theory (DFT) structural relaxations performed on dehydrogenated and monohydrogenated nanocrystalline diamond structures of octahedral {111} and cuboctahedral morphologies, up to approximately 2 nm in diameter. Our results in this size range show an inward transition of dehydrogenated nanodiamond clusters into carbon onion-like structures, with preferential exfoliation of the (111) surfaces, in agreement with experimental observations. However, we have found that this transition may be prevented by monohydrogenation of the surfaces. Bonding of atoms in the surface layers of the relaxed structures, and interlayer bonding has been investigated using the electron charge density.
Publisher: IOP Publishing
Date: 18-03-2009
DOI: 10.1088/0953-8984/21/14/144205
Abstract: In parallel with the development of technological applications for carbon nanotubes, issues related to toxicology and environmental impact are also under increased scrutiny. It is clear from the available literature that the integrity of future carbon nanotube-based devices, our ability to anticipate failure of these devices, and our ability to manage the toxicological and environmental impacts require a detailed understanding of the stability of pure and functionalized carbon nanotubes under a full range of environmental conditions. Motivated by this endeavour, the present study uses a general thermodynamic model to predict the relative stability of carbon nanotubes exposed to a variety of atmospheric adsorbates, and uses them to examine the stability of nanotubes in air, as a function of the relative humidity. In general the results indicate that the adsorption of a sparse coverage of air is thermodynamically favoured, depending on the humidity, and the stability of small diameter nanotubes may be improved by exposure to humid air.
Publisher: Copernicus GmbH
Date: 28-03-2022
DOI: 10.5194/EGUSPHERE-EGU22-10926
Abstract: & & Since the first stoma appeared about 400 million years ago, moisture exchange between lands and the atmosphere extends into the root zone. However, due to its invisibility from the surface, root distribution and its temporal variation are difficult to estimate, which greatly hinders investigation of root zone moisture dynamics, soil-plant water relations, and transpiration modelling. Plant water potential reflects dynamic water condition in vegetation, which is determined by moisture supply in the root zone, atmospheric demand, and plant physiological control. Thus, dynamic water potential can provide a & #8220 eriscope& #8221 to observe root zone hydraulic conditions. Based on this hydraulic connection in the soil-plant-atmosphere continuum (SPAC), plant in iduals work very likely as & #8220 observation wells& #8221 to the whole root zone at predawn, and as & #8220 umping test wells& #8221 in daytime. Meanwhile, stable isotopic composition of water in plant xylem approximately reflects the isotopic signature of bulk root accessible moisture. These hydraulic and isotopic root-zone periscopes provide information to estimate root-zone and plant hydraulic states and their dynamics, and hydraulic properties. In this presentation, we will show how this root-zone periscope concept, based on continuous monitoring of plant water potential, sapflow, and/or isotopic composition of xylem water, has been successfully applied in SPAC model development, root water uptake model improvement, transpiration model parameterisation, as well as investigation of ecohydrological separation.& &
Publisher: Royal Society of Chemistry (RSC)
Date: 2007
DOI: 10.1039/B710189A
Publisher: IOP Publishing
Date: 18-03-2009
DOI: 10.1088/0953-8984/21/14/144203
Abstract: In order to tune the electronic properties of carbon-based nanotubes, attention is now turning to new avenues based on chemical manipulation. The introduction of nitrogen at either doping or alloying concentrations has been shown to give rise to new tubular structures and desirable electronic properties, but a detailed understanding of the strain and thermodynamic properties is still lacking. In this paper a systematic computational study of the structure and thermodynamics of small C(x)N nanotubes is presented (x = 1, 2, 3, 5, and 7). The aim of this work is to investigate which stoichiometries and atomic distributions are likely to be stable under ambient and operating conditions, thereby offering viable candidates for future synthesis efforts. In addition to this, the electronic properties of stable structures are briefly examined, to establish whether small carbon nitride nanotubes may be tailored for emerging technological applications.
Publisher: Elsevier BV
Date: 10-2020
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/C0NR00417K
Abstract: Zinc sulfide (ZnS) nanoparticles are of interest for their luminescent and catalytic properties which are being considered for the next generation of optical, electronic and photovoltaic devices. However, ZnS nanoparticles undergo reversible and irreversible phase transformations under ambient conditions, so a detailed understanding of the nanomorphology is critical in ensuring these desirable properties can be controlled and maintained. Anticipating the structure and transformations in ZnS nanoparticles experimentally is difficult, since selectivity among competing phases, shapes and sizes is intrinsically linked. Presented here are the results of first principle computer simulations and advanced theoretical modelling used to investigate the relationship between size and shape in determining the crystallinity of ZnS nanoparticles. We find that the equilibrium morphology is characterised by {220} facets, irrespective of the size of the particle, but that the presence of different high energy facets introduced kinetically may significantly influence the zinc blende to amorphous ZnS transformation size, as well as the agglomeration behaviour. In addition to this, we model the relationship between transformation size, morphology and the ratio of crystalline core to amorphous shell and show that at small sizes, a core-shell crystalline/amorphous structure is thermodynamically favourable.
Publisher: Wiley
Date: 23-12-2019
DOI: 10.1002/HED.26037
Publisher: No publisher found
Date: 2016
Publisher: Springer Science and Business Media LLC
Date: 03-10-2017
DOI: 10.1038/IJO.2017.240
Publisher: American Chemical Society (ACS)
Date: 05-02-2016
Publisher: American Chemical Society (ACS)
Date: 08-12-2011
DOI: 10.1021/CG101088D
Publisher: Royal Society of Chemistry (RSC)
Date: 2009
DOI: 10.1039/B908532G
Abstract: Fluorescent defects in non-cytotoxic diamond nanoparticles have recently emerged as a preferred candidate for optical labels in biological and medical imaging. The bright fluorescence at 550-800 nm originates from point defects within the particles, some of which appear naturally, while others can be artificially incorporated during synthesis or can be introduced using high-energy ion beam irradiation and subsequent thermal annealing. However, in order for the fluorescent defects to be useful in bio-medical applications there are a number of materials challenges that must be overcome. In this paper, recent studies on nanodiamonds and their use as biolabels are reviewed, while highlighting the links between the physical, chemical and biological issues that arise.
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/B924697E
Publisher: No publisher found
Date: 2015
Publisher: Royal Society of Chemistry (RSC)
Date: 07-10-2014
DOI: 10.1039/C4TC01312C
Publisher: Elsevier BV
Date: 09-2016
Publisher: American Chemical Society (ACS)
Date: 15-03-2012
DOI: 10.1021/JZ300066J
Abstract: Although unpassivated detonation nanodiamonds are known to form tightly bound (and sometimes ordered) superstructures, in most high performance applications the surface are deliberately functionalized, and this can profoundly alter the aggregation behavior. In the present study, we model the aggregation of functionalized nanodiamonds and show that functionalization greatly reduces the Coulombic interactions characteristic of unsaturated particles. Our results provide new insights into the interactions of functionalized nanoparticles.
Publisher: Wiley
Date: 08-01-2019
DOI: 10.1002/CNCR.31944
Publisher: American Geophysical Union (AGU)
Date: 04-2023
DOI: 10.1029/2022WR033566
Abstract: Water ages in plant transpiration reveal important processes of water dynamics in soil‐plant‐atmosphere continuum, which is regulated by water variability and availability in both precipitation inputs and root zone. However, the impacts of climate patterns and rooting depth on water age dynamics in transpiration are inadequately investigated. In this study, variations in root‐zone water replenishment are estimated based on stable isotope compositions of precipitation and plant xylem water, and a piecewise linear mixing water age model is employed to quantify water ages in plant transpiration under five different climates. The results show that water ages in transpiration are very dynamic in all climates with a range between 1 and 229 days. Water replenishments in the root‐zone reveal whether and how much precipitation enters the root zone. Climate patterns control median (mean) water age in plant transpiration but modified by rooting depth. In wet climates, plants mainly rely on water source that originates from precipitation in the current month (accounting for about 60% on average of their water sources), while plants in dry climates largely rely on water source that originates from precipitation fallen on previous months/seasons. These indicate that climate has profound impacts on plant water source by regulating precipitation inputs, root zone water storage and residence time, and evapotranspiration. Despite the limitations of this study, our study provides an alternative way to reveal the precipitation partitioning in root‐zone and seasonal changes in plant water use of precipitation, which highlights different vegetation responses to water variability between climate types.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/C9NR08984E
Abstract: We use direct imaging and dynamic light scattering to reveal the previously unknown dynamic self-assembly of detonation nanodiamond dispersions in water which have been purified without additional surface modification.
Publisher: Elsevier BV
Date: 04-2020
Publisher: Elsevier BV
Date: 10-2023
Publisher: American Chemical Society (ACS)
Date: 18-10-2023
Publisher: AIP Publishing
Date: 12-09-2011
DOI: 10.1063/1.3633724
Abstract: In this work, we report on our full results of the spectroscopic analysis of the quasi-linear S2 state of the prototypical halocarbene, CHF, and its deuterated isotopomer CDF using optical-optical double resonance spectroscopy through the S1 state. A total of 51 S2 state vibrational levels with angular momenta in the range ℓ = 0–3 were observed for CHF, and 76 levels for CDF. Progressions involving all three fundamental vibrations were observed, and rotational constants were determined for each of these levels by measuring spectra through different intermediate J levels of the S1 state. Our experimental results are in excellent agreement with the predictions of vibrational calculations using the discrete variable representation method. The variational vibrational calculations were performed with an analytic potential energy surface fit to ab initio data by the method of interpolating moving least squares. The ab initio data are Davidson-corrected multi-reference configuration interaction calculations based on a state-averaged multiconfigurational self-consistent field reference incorporating a generalized dynamic weighting scheme.
Publisher: American Chemical Society (ACS)
Date: 14-09-2016
DOI: 10.1021/ACSCOMBSCI.6B00094
Abstract: The possibility of band gap engineering in graphene opens countless new opportunities for application in nanoelectronics. In this work, the energy gaps of 622 computationally optimized graphene nanoflakes were mapped to topological autocorrelation vectors using machine learning techniques. Machine learning modeling revealed that the most relevant correlations appear at topological distances in the range of 1 to 42 with prediction accuracy higher than 80%. The data-driven model can statistically discriminate between graphene nanoflakes with different energy gaps on the basis of their molecular topology.
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2CE25814E
Publisher: American Chemical Society (ACS)
Date: 26-01-2011
DOI: 10.1021/MP1002398
Abstract: In this work, we have combined constant-pH molecular dynamics simulations and experiments to provide a quantitative analysis of pH dependent interactions between doxorubicin hydrochloride (DOX) cancer therapeutic and faceted nanodiamond (ND) nanoparticle carriers. Our study suggests that when a mixture of faceted ND and DOX is dissolved in a solvent, the pH of this solvent plays a controlling role in the adsorption of DOX molecules on the ND. We find that the binding of DOX molecules on ND occurs only at high pH and requires at least ∼10% of ND surface area to be fully titrated for binding to occur. As such, this study reveals important mechanistic insight underlying an ND-based pH-controlled therapeutic platform.
Publisher: Wiley
Date: 07-2013
Abstract: Molecular doping and detection are at the forefront of graphene research, a topic of great interest in physical and materials science. Molecules adsorb strongly on graphene, leading to a change in electrical conductivity at room temperature. However, a common impediment for practical applications reported by all studies to date is the excessively slow rate of desorption of important reactive gases such as ammonia and nitrogen dioxide. Annealing at high temperatures, or exposure to strong ultraviolet light under vacuum, is employed to facilitate desorption of these gases. In this article, the molecules adsorbed on graphene nanoflakes and on chemically derived graphene-nanomesh flakes are displaced rapidly at room temperature in air by the use of gaseous polar molecules such as water and ethanol. The mechanism for desorption is proposed to arise from the electrostatic forces exerted by the polar molecules, which decouples the overlap between substrate defect states, molecule states, and graphene states near the Fermi level. Using chemiresistors prepared from water-based dispersions of single-layer graphene on mesoporous alumina membranes, the study further shows that the edges of the graphene flakes (showing p-type responses to NO₂ and NH₃) and the edges of graphene nanomesh structures (showing n-type responses to NO₂ and NH₃) have enhanced sensitivity. The measured responses towards gases are comparable to or better than those which have been obtained using devices that are more sophisticated. The higher sensitivity and rapid regeneration of the sensor at room temperature provides a clear advancement towards practical molecule detection using graphene-based materials.
Publisher: Elsevier BV
Date: 2021
Publisher: American Chemical Society (ACS)
Date: 08-11-2006
DOI: 10.1021/JP065762G
Abstract: Although thermodynamically metastable, planar defects are often observed in many faceted nanomaterials including nanocrystals, nanorods, and nanowires, even after annealing. These planar defects include contact twins and (intrinsic or extrinsic) stacking faults, and are usually neglected by most analytical models. For ex le, many bulk metals have the face-centered cubic structure, but small nanocrystals and nanorods of the same material often exhibit various structural and morphological modifications such as single or multiple symmetric twinning, as well as 5-fold cyclic twinning resulting in decahedral and truncated decahedral nanostructures. Presented here is a general analytical model for the investigation of nanomaterials of arbitrary shape, and with any configuration of planar defects. The model is tested for the case of twinning in unsupported gold nanocrystals and nanorods, and is shown to give results in excellent agreement with experimental and computational studies reported in the literature.
Publisher: Elsevier BV
Date: 07-2016
Publisher: Oxford University Press (OUP)
Date: 12-2013
DOI: 10.1093/IJE/DYT198
Publisher: Wiley
Date: 24-07-2022
Abstract: Machine learning can extract complex structure roperty relationships but is often insufficient to explain how to control or tune the properties of materials, particularly when they are multi‐functional. This study demonstrates the value of combining multi‐target regression and multi‐target causal graphs to address the need to simultaneously control multiple properties of nanomaterials, and the need to translate these relationships into actionable insights. Using nanodiamonds as an exemplar, recursive feature elimination is first used to identify nine structural features that allow simultaneous prediction of their electron charge transfer properties and thermochemical stability to high accuracy by an interpretable random forest regressor. A multi‐target Bayesian network with domain knowledge incorporated via interactive learning using a hill‐climbing algorithm then determines how these important structural features of nanodiamonds relate to their functional properties, proposing causal paths that can be used to inform experimental design.
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C1NR11102G
Abstract: Carbon-based hydrogen storage materials are one of hottest research topics in materials science. Although the majority of studies focus on highly porous loosely bound systems, these systems have various limitations including use at elevated temperature. Here we propose, based on computer simulations, that diamond nanoparticles may provide a new promising high temperature candidate with a moderate storage capacity, but good potential for recyclability. The hydrogenation of nanodiamonds is found to be easily achieved, in agreement with experiments, though we find the stability of hydrogenation is dependent on the morphology of nanodiamonds and surrounding environment. Hydrogenation is thermodynamically favourable even at high temperature in pure hydrogen, ammonia, and methane gas reservoirs, whereas water vapour can help to reduce the energy barrier for desorption. The greatest challenge in using this material is the breaking of the strong covalent C-H bonds, and we have identified that the spontaneous release of atomic hydrogen may be achieved through charging of hydrogenated nanodiamonds. If the degree of induced charge is properly controlled, the integrity of the host nanodiamond is maintained, which indicates that an efficient and recyclable approach for hydrogen release may be possible.
Publisher: Wiley
Date: 14-11-2019
DOI: 10.1002/CNCR.32597
Publisher: IOP Publishing
Date: 30-07-2021
Abstract: Using machine learning methods to analyse and predict events occurring at interfaces is more complicated than applying machine learning to participating entities, such as adsorbates and adsorbents separately. Whether combining molecular or materials descriptors, or explicitly defining the topology of the space in between, the choice of features is critical to successfully understanding the potential energy surface that determines the probability of events, or the importance of unique characteristics that can guide decision making. If reliably defined these descriptors can be used in advanced machine learning methods to model dynamics, co-adsorption and interfacial evolution based on complex data an area traditionally reserved for molecular dynamics or kinetic Monte Carlo. In this perspective, we provide some insights into how interactions and interfaces can be more effectively described and introduce some relevant machine learning methods that go beyond the unsupervised pattern recognition or supervised classification and regression currently preferred by the community.
Publisher: Elsevier BV
Date: 09-2019
Publisher: Elsevier BV
Date: 05-2023
Publisher: American Chemical Society (ACS)
Date: 22-06-2012
DOI: 10.1021/JP3047906
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2JM32618C
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0NR03470C
Abstract: Coarse-grained molecular dynamics simulations of diamond nanoparticles were performed to investigate the effects of size polydispersity on three polyhedral shapes chosen to span a erse space of surface interactions.
Publisher: Hindawi Limited
Date: 2018
DOI: 10.1017/GHEG.2018.7
Abstract: Anti-retroviral therapy (ART) regimes for HIV are associated with raised levels of circulating triglycerides (TGs) in western populations. However, there are limited data on the impact of ART on cardiometabolic risk in sub-Saharan African (SSA) populations. Pooled analyses of 14 studies comprising 21 023 in iduals, on whom relevant cardiometabolic risk factors (including TG), HIV and ART status were assessed between 2003 and 2014, in SSA. The association between ART and raised TG ( .3 mmol/L) was analysed using regression models. Among 10 615 in iduals, ART was associated with a two-fold higher probability of raised TG (RR 2.05, 95% CI 1.51–2.77, I2 = 45.2%). The associations between ART and raised blood pressure, glucose, HbA1c, and other lipids were inconsistent across studies. Evidence from this study confirms the association of ART with raised TG in SSA populations. Given the possible causal effect of raised TG on cardiovascular disease (CVD), the evidence highlights the need for prospective studies to clarify the impact of long term ART on CVD outcomes in SSA.
Publisher: American Chemical Society (ACS)
Date: 05-04-2023
Publisher: Elsevier BV
Date: 09-2020
Publisher: American Chemical Society (ACS)
Date: 02-07-2003
DOI: 10.1021/JP0347421
Publisher: Elsevier BV
Date: 03-2017
Publisher: Elsevier BV
Date: 02-2006
Publisher: No publisher found
Date: 2016
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7NH00125H
Abstract: Sub 3 nm diamond particles show size- and shape-dependent surface reconstructions, which have significant impact to their functionality and performance.
Start Date: 2011
End Date: 12-2013
Amount: $240,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 02-2009
End Date: 02-2014
Amount: $775,000.00
Funder: Australian Research Council
View Funded Activity