ORCID Profile
0000-0001-8431-0804
Current Organisations
Ceres Power Ltd
,
Vrije Universiteit Amsterdam
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Publisher: Proceedings of the National Academy of Sciences
Date: 13-05-2013
Abstract: Antimicrobial peptides are postulated to disrupt microbial phospholipid membranes. The prevailing molecular model is based on the formation of stable or transient pores although the direct observation of the fundamental processes is lacking. By combining rational peptide design with topographical (atomic force microscopy) and chemical (nanoscale secondary ion mass spectrometry) imaging on the same s les, we show that pores formed by antimicrobial peptides in supported lipid bilayers are not necessarily limited to a particular diameter, nor they are transient, but can expand laterally at the nano-to-micrometer scale to the point of complete membrane disintegration. The results offer a mechanistic basis for membrane poration as a generic physicochemical process of cooperative and continuous peptide recruitment in the available phospholipid matrix.
Publisher: Wiley
Date: 08-06-2017
Abstract: Binary encoding of peptide sequences into differential antimicrobial mechanisms is reported. Such sequences are random in composition, but controllable in chain length, are assembled from the same two amino acids, but differ in the stereochemistry of one. Regardless of chirality, the sequences lyse bacteria including the "superbugs" methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci (VRE). Sequences with the same chirality, so-called homochiral sequences, assemble into antimicrobial pores and form contiguous helices that are biologically promiscuous and hemolytic. By contrast, heterochiral sequences that lack such persistence selectively attack bacterial membranes without oligomerizing into visible pores. These results offer a mechanistic rationale for designing membrane-selective and sequence-independent antimicrobials.
Publisher: Elsevier BV
Date: 07-2020
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C6SC02925F
Abstract: A novel mechanism of monolayer poration leading to the rapid exfoliation and lysis of microbial membranes is reported.
Publisher: Elsevier BV
Date: 07-2021
Publisher: Elsevier BV
Date: 02-2020
Publisher: Mineralogical Society
Date: 11-12-2019
DOI: 10.1180/MGM.2019.79
Abstract: Sulfur-bearing monazite-(Ce) occurs in silicified carbonatite at Eureka, Namibia, forming rims up to ~0.5 mm thick on earlier-formed monazite-(Ce) megacrysts. We present X-ray photoelectron spectroscopy data demonstrating that sulfur is accommodated predominantly in monazite-(Ce) as sulfate, via a clino-anhydrite-type coupled substitution mechanism. Minor sulfide and sulfite peaks in the X-ray photoelectron spectra, however, also indicate that more complex substitution mechanisms incorporating S 2– and S 4+ are possible. Incorporation of S 6+ through clino-anhydrite-type substitution results in an excess of M 2+ cations, which previous workers have suggested is accommodated by auxiliary substitution of OH – for O 2– . However, Raman data show no indication of OH – , and instead we suggest charge imbalance is accommodated through F – substituting for O 2– . The accommodation of S in the monazite-(Ce) results in considerable structural distortion that may account for relatively high contents of ions with radii beyond those normally found in monazite-(Ce), such as the heavy rare earth elements, Mo, Zr and V. In contrast to S-bearing monazite-(Ce) in other carbonatites, S-bearing monazite-(Ce) at Eureka formed via a dissolution–precipitation mechanism during prolonged weathering, with S derived from an aeolian source. While large S-bearing monazite-(Ce) grains are likely to be rare in the geological record, formation of secondary S-bearing monazite-(Ce) in these conditions may be a feasible mineral for dating palaeo-weathering horizons.
Publisher: American Chemical Society (ACS)
Date: 04-12-2019
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5SC03260A
Abstract: A conceptual design for artificial antimicrobial viruses is described.
Publisher: Elsevier BV
Date: 09-2020
Publisher: American Vacuum Society
Date: 12-2016
DOI: 10.1116/1.4972417
Abstract: Engineered peptides capable of binding to silica have been used to provide contrast in chemical force microscopy and tested for their capacity to selectively capture silica nanoparticles (NPs). Gold coated atomic force microscopy (AFM) microcantilevers with integrated tips and colloidal probes were functionalized with engineered peptides through a thiol group of a terminal cysteine which was linked via a glycine trimer to a 12-mer binding sequence. The functionalized probes demonstrated a significantly increased binding force on silicon oxide areas of a gold-patterned silicon wafer, whereas plain gold probes, and those functionalized with a random permutation of the silica binding peptide motif or an all-histidine sequence displayed similar adhesion forces to gold and silicon oxide. As the functionalized probes also allowed contact mode imaging subsequently to the adhesion mapping, also the associated friction contrast was measured and found to be similar to the adhesion contrast. Furthermore, the adsorption of silica NPs onto planar gold surfaces functionalized in the same manner was observed to be selective. Notably, the surface coverage with silica NPs was found to decrease with increasing pH, implying the importance of electrostatic interactions between the peptide and the NPs. Finally, the adsorption of silica NPs was monitored via the decrease in fundamental resonance frequency of an AFM microcantilever functionalized with silica binding peptides.
Publisher: Elsevier BV
Date: 02-2011
DOI: 10.1016/J.BIOS.2010.11.043
Abstract: This paper describes the step-wise fabrication and characterisation of a multi-layer dual polarization interferometry (DPI) based biosensor utilising Protein G (ProG) as the bio-recognition layer for the detection of a fragment antibody (Fab'). The biosensor is capable of monitoring the concentration of Fab' product within the extracellular medium of a fed-batch fermentation after leakage from Escherichia coli (E.coli). The activity, stability and functionality of each sensor layer were analysed in situ using DPI, whilst the chemical identity and homogeneity of the chemical layers were assessed ex situ using X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). Two different biotin linkers were found to produce hugely differing surfaces after the capture of NeutrAvidin™ (NA) and biotinylated Protein G (b-ProG). The hydrophilic (PEG)(4)-biotin linker resulted in a surface where the b-ProG layer was deposited and organised above the NA layer producing an active and stable surface, whilst the hydrophobic LC-biotin linker generated a surface where the b-ProG layer was buried within the NA layer leading to variable surfaces and poor binding of the Fab' target. The biosensor has a detection limit of 1.7 μg/ml with a dynamic range covering two orders of magnitude. The sensor can detect the onset of Fab' leakage as early as 2h following product induction, with high signal-to-noise ratios and little interference from extracellular components. Leakage of Fab' followed a biphasic profile, switching to a more rapid rate 20 h after induction, indicating accelerated product loss and the need for cultivation harvest.
Publisher: Wiley
Date: 24-11-2014
DOI: 10.1111/MMI.12838
Publisher: Elsevier BV
Date: 07-2020
Publisher: American Chemical Society (ACS)
Date: 25-10-2008
DOI: 10.1021/LA802264D
Abstract: The velocity dependence of the dynamic contact angle for a glycerol-water mixture wetting two different chemically heterogeneous surfaces (mixed thiols on gold and partially methylated titania, 16 s les in all) was studied. The molecular kinetic theory (MKT) of wetting was used to interpret the dynamic contact angle data. The equilibrium displacement frequency ( K 0) was predominantly determined by the viscous contribution from the bulk liquid, with a minor contribution from the surface. The mean distance between surface sites (lambda) decreased with increasing work of adhesion. The contact line friction coefficient zeta 0 was found to vary exponentially with the work of adhesion, enabling the unit flow volume of the liquid to be obtained.
Publisher: Informa UK Limited
Date: 03-04-2017
Publisher: Royal Society of Chemistry
Date: 2017
Publisher: Wiley
Date: 16-03-2010
DOI: 10.1002/SIA.3244
Abstract: Partial least squares (PLS) regression has been increasingly used as a tool for modelling linear relations between multivariate surface analytical measurements and measures of performance. However, the use of PLS to obtain quantitative predictions has only been partially explored. In this study, we construct a PLS model using time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) and water contact angle (WCA) data obtained from a series of differently treated indium tin oxide (ITO) surfaces. This model displays a reasonable correlation between the WCA values and the SIMS data. To validate the model, ITO surfaces patterned with different areas of wettability were examined using ToF‐SIMS imaging to produce WCA maps. The PLS model was applied to predict the spatial variation in WCA across the s le. The direct measurement of WCA on the patterned ITO surface was achieved using a small‐scale interval grid from picolitre volume water droplets. We present the correlations between the predicted WCA from SIMS and the measured WCA, and highlight the discrepancies that arises in the comparison of the two datasets. This work is of direct benefit to industries where wettability is crucial but direct contact angle measurements are acquired on a scale smaller than it is possible to produce liquid drops, such as the plastic electronics and microfluidics industries. Copyright © 2010 John Wiley & Sons, Ltd.
Publisher: MDPI AG
Date: 09-03-2019
Abstract: Nitric oxide (NO) generating surfaces are potentially promising for improving haemocompatibility of blood-contacting biomaterials. In the present report, Cu-modified poly(vinyl chloride) (PVC) and polyurethane (PU) were prepared via polydopamine (pDA)-assisted chelation. The copper content on the PVC and PU modified surfaces, assessed by inductively coupled plasma - optical emission spectrometry (ICP-OES), were about 3.86 and 6.04 nmol·cm−2, respectively. The Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) data suggest that copper is attached to the polymer surface through complex formation with pDA. The cumulative leaching of copper from modified PVC and PU during the five day incubation in phosphate buffered saline (PBS), measured by inductively coupled plasma mass spectrometry (ICP-MS), was about 50.7 ppb and 48 ppb, respectively which is within its physiological level. Modified polymers were tested for their ability to catalytically generate NO by decomposing of endogenous S-nitrosothiol (GSNO). The obtained data show that Cu-modified PVC and PU exhibited the capacity to generate physiological levels of NO which could be a foundation for developing new biocompatible materials with NO-based therapeutics.
Publisher: Elsevier BV
Date: 03-2020
Publisher: Elsevier BV
Date: 11-2021
Publisher: American Chemical Society (ACS)
Date: 18-12-2009
DOI: 10.1021/JP9095216
Abstract: We demonstrate two methods to improve the quality of organic depth profiling by C(60) sputtering using multilayered reference s les as part of a VAMAS (Versailles project on Advanced Materials and Standards) interlaboratory study. S le cooling was shown previously to be useful in extending the useful depth over which organic materials can be profiled. We reinforce these findings and demonstrate that cooling results in a lower initial sputtering yield to approximately -40 degrees C, but the improvement in useful profiling depth continues as the s le is cooled further, even though there is no further reduction in the initial sputtering yield. We report, for the first time, the use of s le rotation in organic depth profiling and demonstrate that the initial sputtering yield at room temperature is maintained throughout the depth of the s les used in this study. Useful profiling depth and good depth resolution are both associated with a constant sputtering yield. The fact that rotation results in the maintenance of depth resolution underlines the fact that depth resolution is often limited by the development of ion-beam-induced topography. Constant sputtering yield results in a constant secondary-ion yield, after transient processes have occurred, and this allows simple quantification methods to be applied to organic depth profiling data.
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8RA07877G
Abstract: Agricultural production results in wastes that can be re-used to improve the quality of the environment.
Publisher: Elsevier BV
Date: 2020
Publisher: American Chemical Society (ACS)
Date: 28-05-2015
Publisher: Springer Science and Business Media LLC
Date: 18-12-2014
DOI: 10.1038/SREP07529
Publisher: Geological Society of London
Date: 24-11-2021
Abstract: The Nalunaq deposit, Greenland, is a hypozonal, shear zone-hosted, Au deposit. The shear zone has previously been interpreted as having undergone four stages of deformation, accompanied by fluid flow and vein formation. Coupled with previous trapping T estimates, fluid inclusion data are consistent with the trapping of fluids with salinities between 28 and 45 wt% NaCl equiv., from 300 to 475°C during D 2 and D 3 , with pressure varying between c. 800 and 100 MPa. The range reflects pressure cycling during seismic slip-related depressurization events. D 4 fluids were lower salinity and trapped from 200 to 300°C, at c. 50–200 MPa during late-stage normal faulting. The variation in major element chemistry is consistent with the ingress of hypersaline, granitoid equilibrated fluids into the shear zone system and mixing with fluids that had reacted with the host metamorphic rocks. D 4 -stage fluids represent the ingress of meteoric fluids into the system. Gold contents in inclusion fluids range from c. 300 to 10 mg kg −1 . These data are consistent with the high- P–T solubility of Au as AuHS(H 2 S) 3 0 complexes, and Au deposition by decompression and cooling. The high salinities also suggest Au transport as chloride complexes may have been possible. Gold distribution was modified by the release of chemically bound or nanoscale Au during sulfide oxidation at the D 4 stage.
Publisher: Wiley
Date: 23-11-2011
Abstract: Two faces for one matrix: A single bifaceted cyclopeptide block forms highly branched, porous, and intricate fibrillar networks, which span microscopic dimensions and mimic the extracellular matrix to support cell growth and proliferation. The peptide block has two domains connected with triglycine linkers (GGG) the domains consist of positively (blue) and negatively (red) charged heptads that provide interactions between different blocks.
Publisher: American Chemical Society (ACS)
Date: 09-09-2016
DOI: 10.1021/JACS.6B05751
Abstract: A de novo topology of virus-like assembly is reported. The design is a trifaceted coiled-coil peptide helix, which self-assembles into ultrasmall, monodisperse, anionic virus-like shells that encapsulate and transfer both RNA and DNA into human cells. Unlike existing artificial systems, these shells share the same physical characteristics of viruses being anionic, nonaggregating, abundant, hollow, and uniform in size, while effectively mediating gene silencing and transgene expression. These are the smallest virus-like structures reported to date, both synthetic and native, with the ability to adapt and transfer small and large nucleic acids. The design thus offers a promising solution for engineering bespoke artificial viruses with desired functions.
Publisher: Informa UK Limited
Date: 10-03-2021
Publisher: Elsevier BV
Date: 2021
Publisher: Elsevier BV
Date: 07-2019
DOI: 10.1016/J.COLSURFB.2019.03.043
Abstract: The wonder material graphene has numerous potential applications in nanoelectronics, biomedicine, storage devices, etc. Synthesis of graphene is highly challenging due to the toxic chemicals used and its low yield. In the present study, a facile green route for synthesis of reduced graphene oxide (rGO) was carried out using ascorbic acid as reducing agent. rGO was stabilized using Pluronic P123 polymer to give Pluronic stabilized reduced graphene oxide (rGO-P) and gave superior yield (15 mg graphene oxide yielded ˜13 mg rGO-P). Despite the potential neuroscience applications of graphene, the impending toxicological outcome upon interaction with neurons is not well understood. Here, differentiated PC-12 neuron-like cells exposed to rGO-P showed a dose-dependent cytotoxicity. Membrane disruption and cytoskeletal integrity remained uncompromised after 24 h exposure. Oxidative stress in PC-12 was evident due to an increase in ROS generation in dose and time-dependent manner. In vivo acute toxicity was assessed in mice administered with 10 mg/kg body weight of rGO-P. There were no evident changes in behaviour, motor function or other morphological changes. In conclusion, rGO-P was successfully synthesized and provided superior yield. Even though in vitro toxicity testing showed dose-dependent toxicity, in vivo toxic effect was not apparent.
Publisher: Elsevier BV
Date: 12-2020
Publisher: Elsevier
Date: 2021
Publisher: American Chemical Society (ACS)
Date: 27-10-2011
DOI: 10.1021/AC202110X
Abstract: Protein adsorption at solid surfaces is central to many phenomena of medical and technological interest. The determination of the amount of protein attached to the surface is a critical measurement performed by using a wide range of methods. X-ray photoelectron spectroscopy (XPS) is able to provide a straightforward quantitative analysis of the amount of protein adsorbed as an overlayer on a material surface. While XPS is commonly employed to assess qualitatively the amount of adsorbed protein, this is usually expressed in terms of the elemental fraction (or at. %) of nitrogen calculated using an assumption of depth homogeneity despite the fact that this does not linearly scale with the amount of protein. In this paper, we have shown that thicknesses derived from XPS data linearly correlated with spectroscopic ellipsometry data on the same s les with a scatter of 10%. A straightforward equation to convert the concentration of nitrogen from XPS into an equivalent thickness of a protein film is presented. We highlight some discrepancies in the absolute thicknesses determined by XPS and ellipsometry on dried films and quartz crystal microbalance on wet films, which appear likely to result from the inclusion of a contribution from water in the latter two techniques.
Publisher: Elsevier BV
Date: 08-2020
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0MA00596G
Abstract: This work deals with the synthesis of biomolecule-based monometallic Ag and Pd and bimetallic Ag–Pd nanocomposites and their catalytic activity towards etherification reaction.
Publisher: Elsevier BV
Date: 12-2020
Publisher: Springer Science and Business Media LLC
Date: 25-10-2019
DOI: 10.1038/S41529-019-0099-9
Abstract: Accelerated low water corrosion is a form of marine steel corrosion caused by bacterial activity. It has a global spread and is potentially responsible for billions of pounds of damage. We have determined in detail both the chemistry of corrosion products and the associated microbiology at a UK site. The corrosion products form a layered structure with iron sulfides at the steel surface and iron oxides and sulfates in contact with water. The iron sulfides are formed by reaction of steel with hydrogen sulfide formed by sulfate-reducing bacteria and are oxidised through a series of sulfur oxidation states by sulfide-oxidising bacteria, forming acid at all stages and encompassing the whole of the bacterial sulfur cycle. The bacteria involved are endemic in anoxic bed sediment, and the process is a response to the presence of steel as an electron donor, and the generation of anoxic microenvironments within corrosion products.
Publisher: Institute of Combustion Problems
Date: 18-02-2017
DOI: 10.18321/ECTJ472
Abstract: Rice husk derived activated carbons doped with nitrogen have been studied using low temperature nitrogen adsorption, scanning electron microscopy, mercury porosimetry, thermogravimetric analysis combined with mass-spectrometry, differential scanning calorimetry and X-ray photoelectron spectroscopy. It has been shown that N-doped activated carbon produced by high temperature treatment of the starting material soaked with urea, has a significantly higher anion exchange capacity than the other s les studied, which correlates with its higher adsorption capacity towards nitrate ion removal from aqueous solutions with the initial concentration of 5 and 15 ppm.
Publisher: Elsevier BV
Date: 12-2020
Publisher: Elsevier BV
Date: 04-2020
Publisher: American Society for Microbiology
Date: 15-01-2015
DOI: 10.1128/AEM.02733-14
Abstract: Bacterial ghosts are empty cell envelopes of Gram-negative bacteria that can be used as vehicles for antigen delivery. Ghosts are generated by releasing the bacterial cytoplasmic contents through a channel in the cell envelope that is created by the controlled production of the bacteriophage ϕX174 lysis protein E. While ghosts possess all the immunostimulatory surface properties of the original host strain, they do not pose any of the infectious threats associated with live vaccines. Recently, we have engineered the Escherichia coli autotransporter hemoglobin protease (Hbp) into a platform for the efficient surface display of heterologous proteins in Gram-negative bacteria, HbpD. Using the Mycobacterium tuberculosis vaccine target ESAT6 (early secreted antigenic target of 6 kDa), we have explored the application of HbpD to decorate E. coli and Salmonella ghosts with antigens. The use of different promoter systems enabled the concerted production of HbpD-ESAT6 and lysis protein E. Ghost formation was monitored by determining lysis efficiency based on CFU, the localization of a set of cellular markers, fluorescence microscopy, flow cytometry, and electron microscopy. Hbp-mediated surface display of ESAT6 was monitored using a combination of a protease accessibility assay, fluorescence microscopy, flow cytometry and (immuno-)electron microscopy. Here, we show that the concerted production of HbpD and lysis protein E in E. coli and Salmonella can be used to produce ghosts that efficiently display antigens on their surface. This system holds promise for the development of safe and cost-effective vaccines with optimal intrinsic adjuvant activity and exposure of heterologous antigens to the immune system.
Publisher: Wiley
Date: 2011
DOI: 10.1002/SIA.3268
Abstract: We present preliminary results of a VAMAS interlaboratory study on organic depth profiling, TWA2, sub‐project A3 (d). A layered organic system was used to assess the repeatability and comparability of organic depth profiling. Nineteen respondents have provided sufficient data to demonstrate that the coefficients of variation for depth resolution, sputtering yield and relative secondary ion intensities are typically 5–10%. This can be as good as 2–3% with modern instruments, when using a stable sputtering ion current and careful procedures, which approaches the limits set by the s les themselves. The respondents have also demonstrated three methods to improve the quality of depth profiling for this system, namely, s le rotation, cooling to at least − 80 °C and grazing incidence angles for the sputtering ion. Copyright © 2010 John Wiley & Sons, Ltd.
Publisher: American Chemical Society (ACS)
Date: 12-02-2015
DOI: 10.1021/AC503850F
Abstract: The preparation of aminated monolayers with a controlled density of functional groups on silica surfaces through a simple vapor deposition process employing different ratios of two suitable monoalkoxysilanes, (3-aminopropyl)diisopropylethoxysilane (APDIPES) and (3-cyanopropyl)dimethylmethoxysilane (CPDMMS), and advances in the reliable quantification of such tailored surfaces are presented here. The one-step codeposition process was carried out with binary silane mixtures, rendering possible the control over a wide range of densities in a single step. In particular, APDIPES constitutes the functional silane and CPDMMS the inert component. The procedure requires only small amounts of silanes, several ratios can be produced in a single batch, the deposition can be carried out within a few hours and a dry atmosphere can easily be employed, limiting self-condensation of the silanes. Characterization of the ratio of silanes actually bound to the surface can then be performed in a facile manner through contact angle measurements using the Cassie equation. The reliable estimation of the number of surface functional groups was approached with a dual-mode BODIPY-type fluorescence label, which allows quantification by fluorescence and XPS on one and the same s le. We found that fluorescence and XPS signals correlate over at least 1 order of magnitude, allowing for a direct linking of quantitative fluorescence analysis to XPS quantification. Employment of synchrotron-based methods (XPS reference-free total reflection X-ray fluorescence, TXRF) made the traceable quantification of surface functional groups possible, providing an absolute reference for quantitative fluorescence measurements through a traceable measurement chain.
Publisher: American Chemical Society (ACS)
Date: 04-02-2015
DOI: 10.1021/LA503213F
Abstract: We describe the development of a reference biosensor surface, based upon a binary mixture of oligo-ethylene glycol thiols, one of which has biotin at the terminus, adsorbed onto gold as self-assembled monolayers (SAMs). These surfaces were analyzed in detail by X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS) to establish the relationship between the thiol solution composition and the surface composition and structure. We report the use of argon cluster primary ions for the analysis of PEG-thiols, establishing that the different thiols are intimately mixed and that SIMS may be used to measure surface composition of thiol SAMs on gold with a detection limit better than 1% fractional coverage. The adsorption of neutralized chimeric avidin to these surfaces was measured simultaneously using ellipsometry and QCM-D. Comparison of the two measurements demonstrates the expected nonlinearity of the frequency response of the QCM but also reveals a strong variation in the dissipation signal that correlates with the surface density of biotin. These variations are most likely due to the difference in mechanical response of neutralized chimeric avidin bound by just one biotin moiety at low biotin density and two biotin moieties at high density. The transition between the two modes of binding occurs when the average spacing of biotin ligands approaches the diameter of the avidin molecule.
Publisher: American Chemical Society (ACS)
Date: 21-05-2014
DOI: 10.1021/JA411325C
Abstract: An ability to construct biological matter from the molecule up holds promise for applications ranging from smart materials to integrated biophysical models for synthetic biology. Biomolecular self-assembly is an efficient strategy for biomaterial construction which can be programmed to support desired function. A challenge remains in replicating the strategy synthetically, that is at will, and differentially, that is for a specific function at a given length scale. Here we introduce a self-assembly topology enabling a net-like architectural mimetic of native extracellular matrices capable of differential responses to cell adhesion--enhanced mammalian cell attachment and proliferation, and enhanced resistance to bacterial colonization--at the native sub-millimeter length scales. The biological performance of such protein micro-nets directly correlates with their morphological and chemical properties, offering thus an application model for differential extracellular matrices.
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9NR04974F
Abstract: Liquid-phase exfoliation (LPE) has been shown to be capable of producing large quantities of high-quality dispersions suitable for processing into subsequent applications. LPE typically requires surfactants for aqueous dispersions or organic solvents with high boiling point. However, they have major drawbacks such as toxicity, aggregation during solvent evaporation or the presence of residues. Here, dispersions of molybdenum disulfide in acetone are prepared and show much higher concentration and stability than predicted by Hansen parameter analysis. Aiming to understand these enhanced properties, the nanosheets were characterised using UV-visible spectroscopy, zeta potential measurements, atomic force microscopy, Raman spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and scanning transmission microscopy combined with spatially-resolved electron energy loss spectroscopy. Also, the performance of the MoS
Publisher: AIP Publishing
Date: 11-2011
DOI: 10.1063/1.3660779
Abstract: Organic blend thin films consisting of semiconducting poly(3-hexylthiophene) (P3HT) and insulating high-density polyethylene (HDPE) have been fabricated by novel application of a large area wire-bar coating technique in air. The microstructure of P3HT:HDPE blend films reveals a strong structural dependence on initial composition. Preferential segregation of P3HT toward the film surface is observed for all blend compositions, while P3HT (or P3HT-rich) columnar structures enclosed by HDPE (or HDPE-rich) lamellar matrix is distinctive for 50:50 (by weight) blends. The transistors fabricated with P3HT:HDPE blend films show a clear field effect behavior, exhibiting charge carrier mobilities up to 5 × 10−2 cm2/Vs, comparable to the values reported in spin-coated similar blends and of neat P3HT devices. The wire-bar coated blend films and devices are highly repeatable and spatially uniform over large areas (few cm by few cm), demonstrating the suitability of this technique for manufacturing of large area organic electronic devices.
Publisher: Elsevier BV
Date: 2020
Publisher: Elsevier BV
Date: 02-2021
Publisher: Frontiers Media SA
Date: 07-2022
DOI: 10.3389/FIMMU.2022.921272
Abstract: Autotransporters are the core component of a molecular nano-machine that delivers cargo proteins across the outer membrane of Gram-negative bacteria. Part of the type V secretion system, this large family of proteins play a central role in controlling bacterial interactions with their environment by promoting adhesion to surfaces, biofilm formation, host colonization and invasion as well as cytotoxicity and immunomodulation. As such, autotransporters are key facilitators of fitness and pathogenesis and enable co-operation or competition with other bacteria. Recent years have witnessed a dramatic increase in the number of autotransporter sequences reported and a steady rise in functional studies, which further link these proteins to multiple virulence phenotypes. In this review we provide an overview of our current knowledge on classical autotransporter proteins, the archetype of this protein superfamily. We also carry out a phylogenetic analysis of their functional domains and present a new classification system for this exquisitely erse group of bacterial proteins. The sixteen phylogenetic isions identified establish sensible relationships between well characterized autotransporters and inform structural and functional predictions of uncharacterized proteins, which may guide future research aimed at addressing multiple unanswered aspects in this group of therapeutically important bacterial factors.
Publisher: Elsevier BV
Date: 05-2020
Publisher: Elsevier BV
Date: 2017
Publisher: Elsevier BV
Date: 02-2021
Publisher: Springer Science and Business Media LLC
Date: 25-11-2014
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7OB01134B
Abstract: Silica-specific motifs templated into fibre-forming peptides effectively silicify protein fibres.
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for J. Luirink.