ORCID Profile
0000-0001-6496-7008
Current Organisation
Technical University of Munich
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Macromolecular and Materials Chemistry | Synthesis of Materials | Nanomaterials | Plant Physiology | Physical Chemistry of Materials | Colloid and Surface Chemistry | Nanochemistry and Supramolecular Chemistry | Conservation and Biodiversity | Physical Chemistry (Incl. Structural) | Chemical Characterisation of Materials | Plant Biology | Structural Biology (incl. Macromolecular Modelling) | Nanobiotechnology |
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in the Chemical Sciences | Polymeric Materials (e.g. Paints) | Remnant Vegetation and Protected Conservation Areas in Forest and Woodlands Environments | Plastics in Primary Forms | Industrial Chemicals and Related Products not elsewhere classified | Expanding Knowledge in the Biological Sciences | Health not elsewhere classified | Forest and Woodlands Flora, Fauna and Biodiversity
Related Links
Publications
Localization of trehalose in partially hydrated DOPC bilayers: insights into cryoprotective mechanisms
Publisher: The Royal Society
Date: 06-06-2014
Abstract: Trehalose, a natural disaccharide with bioprotective properties, is widely recognized for its ability to preserve biological membranes during freezing and dehydration events. Despite debate over the molecular mechanisms by which this is achieved, and that different mechanisms imply quite different distributions of trehalose molecules with respect to the bilayer, there are no direct experimental data describing the location of trehalose within lipid bilayer membrane systems during dehydration. Here, we use neutron membrane diffraction to conclusively show that the trehalose distribution in a dioleoylphosphatidylcholine (DOPC) system follows a Gaussian profile centred in the water layer between bilayers. The absence of any preference for localizing near the lipid headgroups of the bilayers indicates that the bioprotective effects of trehalose at physiologically relevant concentrations are the result of non-specific mechanisms that do not rely on direct interactions with the lipid headgroups.
Characterization of porosity in sulfide ore minerals: A USANS/SANS study
Publisher: Mineralogical Society of America
Date: 11-2014
DOI: 10.2138/AM-2014-4845
Phenylene bolaamphiphiles: Influence of the substitution pattern on the aggregation behavior and the miscibility with classical phospholipids
Publisher: Wiley
Date: 22-07-2014
In vivo deuteration of a native bacterial biopolymer for structural elucidation using SANS
Publisher: No publisher found
Date: 2004
Structural insights into self-assembly of a slow-evolving and mechanically robust supramolecular gel via time-resolved small-angle neutron scattering
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D2CP01826H
Abstract: The current time-resolved SANS study captures different stages of self-assembly process commencing from nucleation as a function of sonication.
Smooth deuterated cellulose films for the visualisation of adsorbed bio-macromolecules
Publisher: Springer Science and Business Media LLC
Date: 31-10-2016
DOI: 10.1038/SREP36119
Abstract: Novel thin and smooth deuterated cellulose films were synthesised to visualize adsorbed bio-macromolecules using contrast variation neutron reflectivity (NR) measurements. Incorporation of varying degrees of deuteration into cellulose was achieved by growing Gluconacetobacter xylinus in deuterated glycerol as carbon source dissolved in growth media containing D 2 O. The derivative of deuterated cellulose was prepared by trimethylsilylation(TMS) in ionic liquid(1-butyl-3-methylimidazolium chloride). The TMS derivative was dissolved in toluene for thin film preparation by spin-coating. The resulting film was regenerated into deuterated cellulose by exposure to acidic vapour. A common enzyme, horseradish peroxidase (HRP), was adsorbed from solution onto the deuterated cellulose films and visualized by NR. The scattering length density contrast of the deuterated cellulose enabled accurate visualization and quantification of the adsorbed HRP, which would have been impossible to achieve with non-deuterated cellulose. The procedure described enables preparing deuterated cellulose films that allows differentiation of cellulose and non-deuterated bio-macromolecules using NR.
A New Insight into Growth Mechanism and Kinetics of Mesoporous Silica Nanoparticles by in Situ Small Angle X-ray Scattering
Publisher: American Chemical Society (ACS)
Date: 22-07-2015
DOI: 10.1021/ACS.LANGMUIR.5B01637
Abstract: The growth mechanism and kinetics of mesoporous silica nanoparticles (MSNs) were investigated for the first time by using a synchrotron time-resolved small-angle X-ray scattering (SAXS) analysis. The synchrotron SAXS offers unsurpassed time resolution and the ability to detect structural changes of nanometer sized objects, which are beneficial for the understanding of the growth mechanism of small MSNs (∼20 nm). The Porod invariant was used to quantify the conversion of tetraethyl orthosilicate (TEOS) in silica during MSN formation, and the growth kinetics were investigated at different solution pH and temperature through calculating the scattering invariant as a function of reaction time. The growth of MSNs was found to be accelerated at high temperature and high pH, resulting in a higher rate of silica formation. Modeling SAXS data of micelles, where a well-defined electrostatic interaction is assumed, determines the size and shape of hexadecyltrimethylammonium bromide (CTAB) micelles before and after the addition of TEOS. The results suggested that the micelle size increases and the micelle shape changes from ellipsoid to spherical, which might be attributed to the solubilization of TEOS in the hydrophobic core of CTAB micelles. A new "swelling-shrinking" mechanism is proposed. The mechanism provides new insights into understanding MSN growth for the formation of functional mesoporous materials exhibiting controlled morphologies. The SAXS analyses were correlated to the structure of CTAB micelles and chemical reaction of TEOS. This study has provided critical information to an understanding of the growth kinetics and mechanism of MSNs.
Microstructure characterisation through ultra-small-angle neutron scattering
Publisher: Inderscience Publishers
Date: 2018
The inverse hexagonal - inverse ribbon - lamellar gel phase transition sequence in low hydration DOPC:DOPE phospholipid mixtures
Publisher: Elsevier BV
Date: 2009
DOI: 10.1016/J.CHEMPHYSLIP.2008.10.003
Abstract: The inverse hexagonal to inverse ribbon phase transition in a mixed phosphatidylcholine-phosphatidylethanolamine system at low hydration is studied using small and wide angle X-ray scattering. It is found that the structural parameters of the inverse hexagonal phase are independent of temperature. By contrast the length of each ribbon of the inverse ribbon phase increases continuously with decreasing temperature over a range of 50 degrees C. At low temperatures the inverse ribbon phase is observed to have a transition to a gel lamellar phase, with no intermediate fluid lamellar phase. This phase transition is confirmed by differential scanning calorimetry.
Poly(4-vinyl imidazole): A pH-Responsive Trigger for Hierarchical Self-Assembly of Multicompartment Micelles Based upon Triblock Terpolymers
Publisher: Wiley
Date: 09-05-2019
Fluid dynamic lateral slicing of high tensile strength carbon nanotubes
Publisher: Springer Science and Business Media LLC
Date: 11-03-2016
DOI: 10.1038/SREP22865
Abstract: Lateral slicing of micron length carbon nanotubes (CNTs) is effective on laser irradiation of the materials suspended within dynamic liquid thin films in a microfluidic vortex fluidic device (VFD). The method produces sliced CNTs with minimal defects in the absence of any chemical stabilizers, having broad length distributions centred at ca 190, 160 nm and 171 nm for single, double and multi walled CNTs respectively, as established using atomic force microscopy and supported by small angle neutron scattering solution data. Molecular dynamics simulations on a bent single walled carbon nanotube (SWCNT) with a radius of curvature of order 10 nm results in tearing across the tube upon heating, highlighting the role of shear forces which bend the tube forming strained bonds which are ruptured by the laser irradiation. CNT slicing occurs with the VFD operating in both the confined mode for a finite volume of liquid and continuous flow for scalability purposes.
Controlling the characteristics of lamellar liquid crystals using counterion choice, fluorination and temperature
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4SM02109F
Abstract: The effects of temperature, surfactant counterion, and chain fluorination on lamellar phases are explored, revealing a complex interplay of interactions.
Electroactive properties of electrospun silk fibroin for energy harvesting applications
Publisher: Elsevier BV
Date: 12-2019
Drug-Induced Morphology Transition of Self-Assembled Glycopolymers: Insight into the Drug-Polymer Interaction
Publisher: American Chemical Society (ACS)
Date: 16-07-2018
Reversible pH- and Photocontrollable Carbohydrate-Based Surfactants
Publisher: Wiley
Date: 11-09-2014
Abstract: The parallel synthesis and properties of a library of photoswitchable surfactants comprising a hydrophobic butylazobenzene tail-group and a hydrophilic carbohydrate head-group, including the first surfactants to exhibit dual photo- and pH-responsive behavior, is reported. This new generation of surfactants shows varying micelle morphologies, photocontrollable surface tension, and pH-induced aggregation and adsorption.
Quantitative Neutron Dark-Field Imaging of Milk: A Feasibility Study
Publisher: MDPI AG
Date: 14-01-2022
DOI: 10.3390/APP12020833
Abstract: Scattering studies of milk and milk products, which are highly relevant food products on the global market, are often utilized and reported in literature to investigate and understand the subtle microscopic structural differences between dairy s les. These structural features determine the physical properties and ultimately the texture of milk products and, thus, also influence the consumer’s experience. Small-angle neutron scattering is a prominent ex le, which enables observations of length scales, which convey proteins and fat globules in food-grade milk. In addition, deuteration enables contrast variations between the constituents of dairy products. In this study, we investigate the potential of probing small-angle neutron scattering from milk s les through quantitative neutron dark-field imaging using grating interferometry, to establish the feasibility of studying, in particular, fat globules and milk gel structures with this spatially resolved scattering technique.
Adsorption of cationic polyacrylamide at the cellulose–liquid interface: A neutron reflectometry study
Publisher: Elsevier BV
Date: 06-2015
DOI: 10.1016/J.JCIS.2015.02.008
Abstract: The layer thickness and density of high molecular weight cationic polyacrylamide (CPAM) adsorbed at the cellulose-water interface was quantified by neutron reflectometry. The thickness of a full monolayer of CPAM of constant molecular weight (13 MD) but different charge densities, adsorbed with or without NaCl (10(-3) M), was studied. Thin cellulose films (40±7 Å) of roughness <10 Å were produced by spin coating a cellulose acetate-acetone solution and regenerating by alkaline hydrolysis. Film smoothness was greatly improved by controlling the concentration of cellulose acetate (0.13 wt%) and the hydrolysis time in sodium methoxide. The adsorption thickness of CPAM (40% charge 13 MD) at the solid-D2O interface was 43±4 Å on cellulose and 13±2 Å on silicon, an order of magnitude smaller than the CPAM radius of gyration. At constant molecular weight, the thickness of the CPAM layer adsorbed on cellulose increases with polymer charge density (10±1 Å at 5%). Addition of 10(-3) M NaCl decreased the thickness of CPAM layer already adsorbed on cellulose. However, the adsorption layer on cellulose of a CPAM solution equilibrated in 10(-3) M NaCl is much thicker (89±11 Å for 40% CPAM). For high molecular weight CPAMs adsorbed from solution under constant conditions, the adsorption layer can be varied by 1 order of magnitude via control of the variables affecting electrostatic intra- and inter-polymer chain interactions.
Assembly of Multicompartment Glycopolymer Worms in Aqueous Solution
Publisher: American Chemical Society (ACS)
Date: 12-04-2023
Conformational selection of the intrinsically disordered plant stress protein COR15A in response to solution osmolarity – an X-ray and light scattering study
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9CP01768B
Abstract: The plant stress protein COR15A stabilizes chloroplast membranes during freezing.
Wormlike micelle formation of novel alkyl-tri(ethylene glycol)-glucoside carbohydrate surfactants: Structure–function relationships and rheology
Publisher: Elsevier BV
Date: 11-2018
DOI: 10.1016/J.JCIS.2018.05.060
Abstract: Carbohydrates are appealing non-ionic surfactant head-groups as they are naturally abundant, generally biocompatible and biodegradable, and readily functionalized. Here, seven novel carbohydrate based surfactants (CBS) have been synthesized that contain a tri-ethylene glycol (TEG) linker between a glucose head-group and alkyl tail-group, with linear saturated (C8-18) and unsaturated (C18:1) alkyl chains. The aqueous adsorption and self-assembly of these surfactants was explored using tensiometry and small- and ultra-small-angle neutron scattering (SANS and USANS). With SANS we observed elongation from spherical to cylindrical micelles with increasing alkyl chain length. C16 and C18 chains exhibited pronounced Krafft points, yet formed worm-like micelles as single components upon heating to 43 and 48 °C respectively. The introduction of mono-unsaturation in the form of a C18:1 chain reduced the Krafft point and gave a surfactant that produced worm-like micelles in water without additives at room temperature. We also observed micellar elongation for C12 and C14 chains at 50 °C due to dehydration of the TEG linker. The room temperature worm-like micelles were further characterized using rheo-SANS and rheology, revealing the C18:1 surfactant to exhibit near ideal Maxwell behavior at low concentrations (2.9 wt.%). These results provide insight into structure-function relationships for CBS, and demonstrate a promising molecular candidate for the formation of viscoelastic worm-like micellar solutions.
Ion transport in complex layered graphene-based membranes with tuneable interlayer spacing
Publisher: American Association for the Advancement of Science (AAAS)
Date: 05-02-2016
Abstract: A combination of experiments and simulations unveils unusual nanoconfined ion transport in layered graphene membranes.
Changes in microfibril angle in cyclically deformed dry coir fibers studied by in-situ synchrotron X-ray diffraction
Publisher: Springer Science and Business Media LLC
Date: 02-12-2006
In Situ SAXS Measurement and Molecular Dynamics Simulation of Magnetic Alignment of Hexagonal LLC Nanostructures
Publisher: MDPI AG
Date: 02-12-2018
Abstract: The alignment of nanostructures in materials such as lyotropic liquid crystal (LLC) templated materials has the potential to significantly improve their performances. However, accurately characterising and quantifying the alignment of such fine structures remains very challenging. In situ small angle X-ray scattering (SAXS) and molecular dynamics were employed for the first time to understand the hexagonal LLC alignment process with magnetic nanoparticles under a magnetic field. The enhanced alignment has been illustrated from the distribution of azimuthal intensity in the s les exposed to magnetic field. Molecular dynamics simulations reveal the relationship between the imposed force of the magnetic nanoparticles under magnetic field and the force transferred to the LLC cylinders which leads to the LLC alignment. The combinational study with experimental measurement and computational simulation will enable the development and control of nanostructures in novel materials for various applications.
Ultrastructural modeling of small angle scattering from photosynthetic membranes
Publisher: Springer Science and Business Media LLC
Date: 18-12-2019
DOI: 10.1038/S41598-019-55423-0
Abstract: The last decade has seen a range of studies using non-invasive neutron and X-ray techniques to probe the ultrastructure of a variety of photosynthetic membrane systems. A common denominator in this work is the lack of an explicitly formulated underlying structural model, ultimately leading to ambiguity in the data interpretation. Here we formulate and implement a full mathematical model of the scattering from a stacked double bilayer membrane system taking instrumental resolution and polydispersity into account. We validate our model by direct simulation of scattering patterns from 3D structural models. Most importantly, we demonstrate that the full scattering curves from three structurally typical cyanobacterial thylakoid membrane systems measured in vivo can all be described within this framework. The model provides realistic estimates of key structural parameters in the thylakoid membrane, in particular the overall stacking distance and how this is ided between membranes, lumen and cytoplasmic liquid. Finally, from fitted scattering length densities it becomes clear that the protein content in the inner lumen has to be lower than in the outer cytoplasmic liquid and we extract the first quantitative measure of the luminal protein content in a living cyanobacteria.
Phase Behavior, Small-Angle Neutron Scattering and Rheology of Ternary Nonionic Surfactant–Oil–Water Systems: A Comparison of Oils
Publisher: American Chemical Society (ACS)
Date: 06-03-2013
DOI: 10.1021/LA400100N
Abstract: The phase behavior of the nonionic surfactant Triton X-100 (polyethylene glycol p-(1,1,3,3-tetramethylbutyl)-phenyl ether) was studied in two three-component systems: Triton-water-p-xylene and Triton-water-trichloroethylene. It was found that the aromatic solvent was able to produce monophasic soft matter systems at a significantly greater range of compositions. The structural characteristics of the phases generated were analyzed by small-angle neutron scattering, showing evidence for microemulsion, lamellar, and reverse-microemulsion phases. In addition, for the Triton-water-p-xylene system, an L3 "sponge" phase was found in a water-rich region of the phase diagram and the properties of this were examined using rheological measurements. The differences in phase behavior are discussed in light of the solvation properties of the surfactant in the different solvents studied. Most notably, xylene appears to favor phases with low-curvature interfaces, suggesting preferential solvation of the central phenyl group of Triton.
High aspect ratio nanocellulose from an extremophile spinifex grass by controlled acid hydrolysis
Publisher: Springer Science and Business Media LLC
Date: 26-06-2017
Determination of Na+ binding parameters by relaxation analysis of selected Na-23 NMR coherences: RNA, BSA and SDS
Publisher: Wiley
Date: 2005
DOI: 10.1002/MRC.1541
Abstract: Nuclear magnetic resonance provides several unique means of investigating the interactions between different inorganic ions and various macromolecules. (23)Na is a quadrupolar nucleus, meaning that relaxation analysis of the various coherences allows the measurement of its binding to biological macromolecules. In this study, we analyzed the quadrupolar relaxation of (23)Na(+) longitudinal magnetization and single- and triple-quantum coherences in aqueous systems containing RNA, bovine serum albumin and sodium dodecyl sulfate micelles. The effectiveness of the James-Noggle method for determining binding constants was evaluated in these systems, and also the applicability of various (23)Na coherences in providing information on the extent and affinity of binding to the three different classes of biomolecules.
Nematic effects and strain coupling in entangled polymer melts under strong flow
Publisher: American Physical Society (APS)
Date: 24-08-2016
Biodegradability of Poly-3-hydroxybutyrate/Bacterial Cellulose Composites under Aerobic Conditions, Measured via Evolution of Carbon Dioxide and Spectroscopic and Diffraction Methods
Publisher: American Chemical Society (ACS)
Date: 28-07-2015
DOI: 10.1021/ES5044485
Abstract: Poly-3-hydroxybutyrate (PHB) and bacterial cellulose (BC) are both natural polymeric materials that have the potential to replace traditional, nonrenewable polymers. In particular, the nanofibrillar form of bacterial cellulose makes it an effective reinforcement for PHB. Neat PHB, bacterial cellulose, and a composite of PHB/BC produced with 10 wt % cellulose were composted under accelerated aerobic test conditions, with biodegradability measured by the carbon dioxide evolution method, in conjunction with spectroscopic and diffraction methods to assess crystallinity changes during the biodegradation process. The PHB/BC composite biodegraded at a greater rate and extent than that of PHB alone, reaching 80% degradation after 30 days, whereas PHB did not reach this level of degradation until close to 50 days of composting. The relative crystallinity of PHB and PHB in the PHB/BC composite was found to increase in the initial weeks of degradation, with degradation occurring primarily in the amorphous region of the material and some recrystallization of the amorphous PHB. Small angle X-ray scattering indicates that the change in PHB crystallinity is accompanied by a change in morphology of semicrystalline lamellae. The increased rate of biodegradability suggests that these materials could be applicable to single-use applications and could rapidly biodegrade in compost on disposal.
Thermal annealing behaviour and gel to crystal transition of a low molecular weight hydrogelator
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C6SM02431A
Abstract: The thermal annealing behaviour of an electrolyte-triggered calixarene hydrogelator is found to depend strongly on the specific metal chloride used. While the lithium chloride gel showed typical gel-sol transitions as a function of temperature, the magnesium chloride gel was found to repeatedly strengthen with heat-cool cycles. Structural investigations using small-angle neutron scattering, and scanning probe microscopy, suggest that the annealing behaviour is associated with a change in morphology of the fibrous structures supporting the gel. On prolonged standing at room temperature, the magnesium chloride gel underwent a gel-crystal transition, with the collapsing gel accompanied by the deposition of crystals of a magnesium complex of the proline-functionalised calix[4]arene gelator.
Shear-induced alignment of self-associated hemoglobin in human erythrocytes: small angle neutron scattering studies
Publisher: Springer Science and Business Media LLC
Date: 06-05-2004
DOI: 10.1007/S00249-004-0408-1
Abstract: Small angle neutron scattering (SANS) was performed on suspensions of actively metabolising human erythrocytes in the constant shear field induced by a Couette cell. The SANS pattern recorded on a two-dimensional detector was a function of the shear rate at zero shear, the SANS pattern had radial symmetry around the direction of the beam. The radial average of the SANS pattern consisted of a broad intensity maximum superimposed on a decay. The intensity maximum at q = 0.1 A(-1) was attributed to isotropically oriented self-associated complexes of the tetrameric oxygen transport protein hemoglobin inside the erythrocytes. A flow curve of the cell suspension was used to identify at what shear rate a suspension of uniaxially oriented ellipsoidal cells is produced. The radial symmetry of the SANS patterns persisted until the shear rate was sufficient to produce a suspension of uniaxially oriented ellipsoidal cells. Again, an intensity maximum was present in directions parallel and orthogonal to the shear axis, but this intensity maximum was superimposed upon quite different intensity decays in each direction from that of the primary neutron beam. The angular range of the SANS instrument was limited, however the results from shear-induced structural changes is consistent with a model that involves hemoglobin complexes that are aligned with respect to the plasma membranes of the elongated cells.
Sugar Concentration and Arrangement on the Surface of Glycopolymer Micelles Affect the Interaction with Cancer Cells
Publisher: American Chemical Society (ACS)
Date: 14-12-2019
DOI: 10.1021/ACS.BIOMAC.8B01406
Abstract: Glycopolymer-coated nanoparticles have attracted significant interest over the past few years, because of their selective interaction with carbohydrate receptors found on the surface of cells. While the type of carbohydrate determines the strength of the ligand-receptor interaction, the presentation of the sugar can be highly influential as the carbohydrate needs to be accessible in order to display good binding. To shine more light on the relationship between nanoparticle structure and cell uptake, we have designed several micelles based on fructose containing block copolymers, which are selective to GLUT5 receptors found on breast cancer cell lines. The polymers were based on poly-d,l-lactide (PLA), poly(2-hydroxyethyl) acrylate (PHEA), and poly(1- O-acryloyl-β-d-fructopyranose) (P[1- O-AFru]). A set of six micelles was synthesized based on four fructose containing micelles (PLA
The spatial modulation of microfibril angle in the woody tissue of maturing tree stems studied with synchrotron radiation
Publisher: CSIRO Publishing
Date: 2020
DOI: 10.1071/BT18229
Abstract: Spatial variations in the microfibril angle (MFA) of cellulose are mapped on in idual radial sections of wood from the maturing stems of Australian tree species (Acacia floribunda, Acacia suaveolens, Acacia doratoxylon, Acacia havilandiorum, Brachychiton populneus and Bertya cunninghamii) from different rainfall and soil nutrient availabilities using synchrotron wide angle X-ray scattering. For the three species with the smallest radial variation there is a clear linear relationship between the MFA with Young’s modulus and wood density with data published previously for these s les. The other three s les show a large radially symmetric variation in MFA across the radial section either having a continuous change from large MFA in the stem’s centre to small value close to the bark or the reverse, small MFA at the centre to larger values close to the bark. For these s les, a strong linear correlation between the Young’s modulus and density and the MFA is not apparent. We conclude that spatially localised measurements of MFA provide an important insight in the adaptation of wood tissue to environmental conditions.
Heterotopic Ossifications in Patients After Severe Blunt Trauma With and Without Head Trauma: Incidence and Patterns of Distribution
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-2001
DOI: 10.1097/00005131-200105000-00001
Abstract: To investigate the incidence and distribution of heterotopic ossifications in patients with blunt multiple trauma with and without associated head trauma. Retrospective. Level I trauma center. Patients were included if they were treated between August 1987 and September 1995. Inclusion criteria included age between 16 and 65 years, injury severity score (ISS) of more than twenty points, and clinical reexamination performed more than three years after the initial injury. The records of each patient were abstracted to determine the ISS, the Glasgow coma score (GCS), and parameters describing the course of intensive care. For each patient, a reexamination was performed between January and September 1998. Patients with multiple trauma and associated head trauma (Group PTH, polytrauma, GCS less than nine points, and head computed tomography scan abnormalities) and patients with multiple trauma without associated head trauma (Group PT, polytrauma, GCS of at least nine points, and normal head computed tomography scans) were compared. A clinical reexamination was performed to evaluate functional outcome. Sixty-four patients belonged to Group PTH and 124 patients belonged to Group PT. There were no differences in the age (Group PTH, 28.9 +/- 1.6 years Group PT, 29.2 +/- 2.1 years) or severity of injury (ISS Group PTH, 31.0 +/- 5.3 points ISS Group PT, 33.0 +/- 6.1 points) among patients in the two groups. The overall incidence of periarticular heterotopic ossification was comparable in patients with multiple trauma with and without head injury (Group PTH, 30 of 64 patients [46.9 percent] Group PT, 53 of 124 patients [42.7 percent]). The duration of ventilation was significantly higher in Group PT (Group PTH, 9.3 +/- 2.4 days Group PT, 14.2 +/- 3.1 days p = 0.02). In the subgroups in which heterotopic ossification developed (PT-HO and PTH-HO), patients in PT-HO had a significantly higher incidence of heterotopic ossification, as compared with patients in PTH-HO at initially uninjured joints (Group PTH-HO, 1 of 30 patients [3.3 percent] Group PT-HO, 10 of 53 patients [18.9 percent] p = 0.04). There was a high incidence of heterotopic ossification around those joints that were initially classified as uninjured in patients without head trauma. This finding suggests that pathogenic pathways independent of head trauma, such as long-term ventilation, play a main role. Causative factors for the development of heterotopic ossification at initially uninjured joints in long-term ventilated patients with multiple trauma with and without head trauma remain to be elucidated.
Manipulation of polyhydroxybutyrate properties through blending with ethyl-cellulose for a composite biomaterial
Publisher: Hindawi Limited
Date: 2011
DOI: 10.1155/2011/651549
Abstract: Polyhydroxybutyrate (PHB) is widely used as a biomaterial in medical and tissue-engineering applications, a relatively high crystallinity limits its application. Blending PHB with ethyl-cellulose (EtC) was readily achieved to reduce PHB crystallinity and promote its degradation under physiological conditions without undue influence on biocompatibility. Material strength of composite films remained unchanged at 6.5 ± 0.6 MPa with 40% (w/w) EtC loadings. Phase separation between the two biopolymers was determined with PHB crystallinity decreasing from 63% to 47% for films with the same loading. This reduction in crystallinity supported an increase in the degradation rates of composite films from 0.39 to 0.81% wk −1 for PHB and its composite, respectively. No significant change in morphology and proliferation of olfactory ensheathing cells were observed with the composites despite significant increases in average surface roughness ( R a ) of the films from 2.90 to 3.65 μ m for PHB and blends with 80% (w/w) EtC, respectively.
Bio-deuterated cellulose thin films for enhanced contrast in neutron reflectometry
Publisher: Springer Science and Business Media LLC
Date: 03-11-2017
Hybrid Nanoparticles for Haloperidol Encapsulation: Quid Est Optimum?
Publisher: MDPI AG
Date: 30-11-2021
Abstract: The choice of drug delivery carrier is of paramount importance for the fate of a drug in a human body. In this study, we have prepared the hybrid nanoparticles composed of FDA-approved Eudragit L100-55 copolymer and polymeric surfactant Brij98 to load haloperidol—an antipsychotic hydrophobic drug used to treat schizophrenia and many other disorders. This platform shows good drug-loading efficiency and stability in comparison to the widely applied platforms of mesoporous silica (MSN) and a metal–organic framework (MOF). ZIF8, a biocompatible MOF, failed to encapsulate haloperidol, whereas MSN only showed limited encapsulation ability. Isothermal titration calorimetry showed that haloperidol has low binding with the surface of ZIF8 and MSN in comparison to Eudragit L100-55/Brij98, thus elucidating the striking difference in haloperidol loading. With further optimization, the haloperidol loading efficiency could reach up to 40% in the hybrid Eudragit L100-55/Brij98 nanoparticles with high stability over several months. Differential scanning calorimetry studies indicate that the encapsulated haloperidol stays in an amorphous state inside the Eudragit L100-55/Brij98 nanoparticles. Using a catalepsy and open field animal tests, we proved the prolongation of haloperidol release in vivo, resulting in later onset of action compared to the free drug.
Distribution of Solute Molecules in Bilayer Stacks by Medium Angle Diffraction
Publisher: Elsevier BV
Date: 02-2016
Fluorinated lamellar phases: structural characterisation and use as templates for highly ordered silica materials
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4SM00666F
Abstract: Highly ordered silica was synthesised by using a lamellar phase comprising the anionic fluorinated surfactant sodium perfluorooctanoate and the partially-fluorinated co-surfactant/oil 1 H ,1 H ,2 H ,2 H -perfluorooctan-1-ol in water.
Margination of 2D Platelet Microparticles in Blood
Publisher: American Chemical Society (ACS)
Date: 23-02-2023
Intrinsically Disordered Stress Protein COR15A Resides at the Membrane Surface during Dehydration
Publisher: Elsevier BV
Date: 08-2017
Spontaneous Self-Assembly of Thermoresponsive Vesicles Using a Zwitterionic and an Anionic Surfactant
Publisher: American Chemical Society (ACS)
Date: 29-06-2020
Non-reversible heat-induced gelation of a biocompatible Fmoc-hexapeptide in water
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0NR00289E
Abstract: A biocompatible Fmoc-hexapeptide which forms hydrogels at physiological pH upon heating is reported.
Investigation of the phase morphology of bacterial PHA inclusion bodies by contrast variation SANS
Publisher: Elsevier BV
Date: 11-2006
Location of sugars in multilamellar membranes at low hydration
Publisher: Elsevier BV
Date: 11-2006
Picosecond dynamics in haemoglobin from different species: A quasielastic neutron scattering study
Publisher: Elsevier BV
Date: 10-2014
DOI: 10.1016/J.BBAGEN.2014.06.007
Abstract: Dynamics in haemoglobin from platypus (Ornithorhynchus anatinus), chicken (Gallus gallus domesticus) and saltwater crocodile (Crocodylus porosus) were measured to investigate response of conformational motions on the picosecond time scale to naturally occurring variations in the amino acid sequence of structurally identical proteins. Protein dynamics was measured using incoherent quasielastic neutron scattering. The quasielastic broadening was interpreted first with a simple single Lorentzian approach and then by using the Kneller-Volino Brownian dynamics model. Mean square displacements of conformational motions, diffusion coefficients of internal dynamics and residence times for jump-diffusion between sites and corresponding effective force constants (resilience) and activation energies were determined from the data. Modifications of the physicochemical properties caused by mutations of the amino acids were found to have a significant impact on protein dynamics. Activation energies of local side chain dynamics were found to be similar between the different proteins being close to the energy, which is required for the rupture of single hydrogen bond in a protein. The measured dynamic quantities showed significant and systematic variations between the investigated species, suggesting that they are the signature of an evolutionary adaptation process stimulated by the different physiological environments of the respective protein.
Small angle neutron scattering on an absolute intensity scale and the internal surface of diatom frustules from three species of differing morphologies
Publisher: Springer Science and Business Media LLC
Date: 03-02-2013
DOI: 10.1007/S00249-013-0889-X
Abstract: The internal nanostructure of the diatoms Cyclotella meneghiniana, Seminavis robusta and Achnanthes subsessilis was investigated using small angle neutron scattering (SANS) to examine thin biosilica s les, consisting of isotropic (powder) from their isolated cell walls. The interpretation of SANS data was assisted by several other measurements. The N2 adsorption, interpreted within the Branuer-Emmet-Teller isotherm, yielded the specific surface area of the material. Fourier transform infrared (FTIR) and Raman spectroscopy indicates that the isolated material is amorphous silica with small amounts of organic cell wall materials acting as a filling material between the silica particles. A two-phase (air and amorphous silica) model was used to interpret small angle neutron scattering data. After correction for instrumental resolution, the measurements on two SANS instruments covered an extended range of scattering vectors 0.0011 nm(-1) < q < 5.6 nm(-1), giving an almost continuous SANS curve over a range of scattering vectors, q, on an absolute scale of intensity for each s le. Each of the s les gave a characteristic scattering curve where log (intensity) versus log (q) has a -4 dependence, with other features superimposed. In the high-q regime, departure from this behaviour was observed at a length-scales equivalent to the proposed unitary silica particle. The limiting Porod scattering law was used to determine the specific area per unit of volume of each s le illuminated by the neutron beam. The Porod behaviour, and ergence from this behaviour, is discussed in terms of various structural features and the proposed mechanisms for the bio-assembly of unitary silica particles in frustules.
Structural Characterization of Nanoparticle-Supported Lipid Bilayer Arrays by Grazing Incidence X-ray and Neutron Scattering
Publisher: American Chemical Society (ACS)
Date: 10-01-2023
Phospholipid Membrane Protection by Sugar Molecules during Dehydration-Insights into Molecular Mechanisms Using Scattering Techniques
Publisher: MDPI AG
Date: 12-04-2013
DOI: 10.3390/IJMS14048148
Structure and Property Changes in Self-Assembled Lubricin Layers Induced by Calcium Ion Interactions
Publisher: American Chemical Society (ACS)
Date: 02-03-2017
DOI: 10.1021/ACS.LANGMUIR.6B03992
Abstract: Lubricin (LUB) is a "mucin-like" glycoprotein found in synovial fluids and coating the cartilage surfaces of articular joints, which is now generally accepted as one of the body's primary boundary lubricants and antiadhesive agents. LUB's superior lubrication and antiadhesion are believed to derive from its unique interfacial properties by which LUB molecules adhere to surfaces (and biomolecules, such as hyaluronic acid and collagen) through discrete interactions localized to its two terminal end domains. These regionally specific interactions lead to self-assembly behavior and the formation of a well-ordered "telechelic" polymer brush structure on most substrates. Despite its importance to biological lubrication, detailed knowledge on the LUB's self-assembled brush structure is insufficient and derived mostly from indirect and circumstantial evidence. Neutron reflectometry (NR) was used to directly probe the self-assembled LUB layers, confirming the polymer brush architecture and resolving the degree of hydration and level of surface coverage. While attempting to improve the LUB contrast in the NR measurements, the LUB layers were exposed to a 20 mM solution of CaCl
Toward the Fabrication of Advanced Nanofiltration Membranes by Controlling Morphologies and Mesochannel Orientations of Hexagonal Lyotropic Liquid Crystals
Publisher: MDPI AG
Date: 21-07-2017
Structure-property relationships of elementary bamboo fibers
Publisher: Springer Science and Business Media LLC
Date: 05-10-2016
Deuterated Bacterial Cellulose Dissolution in Ionic Liquids
Publisher: American Chemical Society (ACS)
Date: 06-07-2021
Structural Evolution of Wormlike Micellar Fluids Formed by Erucyl Amidopropyl Betaine with Oil, Salts, and Surfactants
Publisher: American Chemical Society (ACS)
Date: 16-09-2016
DOI: 10.1021/ACS.LANGMUIR.6B01735
Abstract: Solutions of extended, flexible cylindrical micelles, often known as wormlike micelles, have great potential as the base for viscoelastic complex fluids in oil recovery, drilling, and lubrication. Here, we study the morphology and nanostructural characteristics of a model wormlike micellar fluid formed from erucyl amidopropyl betaine (EAPB) in water as a function of a erse range of additives relevant to complex fluid formulation. The wormlike micellar dispersions are extremely oleo-responsive, with even as little as 0.1% hydrocarbon oil causing a significant disruption of the network and a decrease in zero-shear viscosity of around 100-fold. Simple salts have little effect on the local structure of the wormlike micelles but result in the formation of fractal networks at larger length scales, whereas even tiny amounts of small organic species such as phenol can cause unexpected phase transitions. When forming mixtures with other surfactants, a vast array of self-assembled structures are formed, from spheres to ellipsoids, lamellae, and vesicles, offering the ultimate sensitivity in designing formulations with specific nanostructural characteristics.
Visualization and Quantification of IgG Antibody Adsorbed at the Cellulose-Liquid Interface
Publisher: American Chemical Society (ACS)
Date: 12-07-2017
DOI: 10.1021/ACS.BIOMAC.7B00593
Abstract: Quantification of adsorbed biomolecules (enzymes, proteins) at the cellulose interface is a major challenge in developing eco-friendly biodiagnostics. Here, a novel methodology is developed to visualize and quantify the adsorption of antibody from solution to the cellulose-liquid interface. The concept is to deuterate cellulose by replacing all nonexchangeable hydrogens from the glucose rings with deuterium in order to enhance the scattering contrast between the cellulose film surface and adsorbed antibody molecules. Deuterated cellulose (DC) was obtained from bacterial (Gluconacetobacter xylinus strain) cellulose, which was grown in heavy water (D
In vivo deuteration strategies for neutron scattering analysis of bacterial polyhydroxyoctanoate
Publisher: Springer Science and Business Media LLC
Date: 15-05-2008
DOI: 10.1007/S00249-008-0333-9
Abstract: The cultivation of microorganisms on deuterated substrates has allowed us to control deuterium incorporation into biopolymer systems which is important for characterisation using neutron scattering techniques. Bacterial polyhydroxyoctanoate (PHO) is a polyester formed within inclusions inside bacterial cells and was deuterated in vivo under various conditions to characterise the formation of these inclusions by neutron scattering. Manipulation of deuterated media during microbial growth and PHO production phases resulted in polymer with partial or complete substitution of hydrogen by deuterium, as shown by gas chromatography. Sequential feeding of hydrogenated and deuterated forms of the same precursor was used to demonstrate that neutron scattering analysis could be used to differentiate between chemically similar phases in these polymer inclusions.
Na+ and solute diffusion in aqueous channels of Myverol bicontinuous cubic phase: PGSE NMR and computer modelling
Publisher: Wiley
Date: 22-03-2017
DOI: 10.1002/MRC.4432
Abstract: The apparent diffusion coefficients of
Effect of deuteration on the phase behaviour and structure of lamellar phases of phosphatidylcholines – Deuterated lipids as proxies for the physical properties of native bilayers
Publisher: Elsevier BV
Date: 05-2019
DOI: 10.1016/J.COLSURFB.2019.01.040
Abstract: Deuteration of phospholipids is a common practice to elucidate membrane structure, dynamics and function, by providing selective visualisation in neutron scattering, nuclear magnetic resonance and vibrational spectroscopy. It is generally assumed that the properties of the deuterated lipids are identical to those of the protiated lipids, and while a number of papers have compared the properties of different forms, to date this has been no systematic study of the effects over a range of conditions. Here we present a study of the effects of deuteration on the organisation and phase behaviour of four common phospholipids (DSPC, DPPC, DMPC, DOPC), observing the effect of chain deuteration and headgroup deuteration on lipid structure and phase behaviour. For saturated lipids in excess water the gel-fluid phase transition temperature is 4.3 ± 0.1 °C lower for lipids with deuterated chains compared to protiated chains, consistent with previous work. Despite this significant change, well away from the transition structural changes as measured by powder small angle X-ray scattering are small and within errors. To investigate this further, measurements were carried out on oriented multilamellar stacks of DOPC in the fluid phase at reduced hydration. Neutrons are used in conjunction with contrast variation to elucidate the role of the deuteration explicitly. It is found that deuterated chains cause a reduction in the lamellar repeat spacing and bilayer thickness, but deuterated headgroups cause an increase. Consequences for the interpretation of Neutron Scattering data with deuterated lipids are discussed.
Light-induced structural evolution of photoswitchable carbohydrate-based surfactant micelles
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4CC07657E
Abstract: We report the light-induced structural evolution of photoswitchable carbohydrate-based surfactant micelles using time-resolved small-angle neutron scattering (TR-SANS), monitoring the structural changes in micellisation in situ over time and demonstrating for the first time the course and implications of this process.
Cellulose Dissolution in Ionic Liquid: Ion Binding Revealed by Neutron Scattering
Publisher: American Chemical Society (ACS)
Date: 20-09-2018
Correlation between Drug Loading Content and Biological Activity: The Complexity Demonstrated in Paclitaxel-Loaded Glycopolymer Micelle System
Publisher: American Chemical Society (ACS)
Date: 15-02-2019
DOI: 10.1021/ACS.BIOMAC.8B01707
Abstract: Drug delivery carriers are now widely established because they can increase the therapeutic efficiency of drugs. In general, the aim in this field is to create effective carriers that have large amounts of drugs loaded to minimize drug carrier material that needs to be disposed of. However, there has been little attention so far in the literature on the effect of the amount of loaded drugs on the biological activity. In this paper, we are trying to answer the question of how the drug-loading content will affect the in vitro activity. We use two methods to load paclitaxel (PTX) into micelles based on the glycopolymer, poly(1- O-methacryloyl-β-d-fructopyranose)- block-poly(methyl methacylate) (Poly(1- O-MAFru)
Effect of head-group size on micellization and phase behavior in quaternary ammonium surfactant systems
Publisher: American Chemical Society (ACS)
Date: 09-1993
DOI: 10.1021/J100141A054
Micron-scale restructuring of gelling silica subjected to shear
Publisher: Elsevier BV
Date: 2019
DOI: 10.1016/J.JCIS.2018.08.024
Abstract: We examine the time dependent viscometric behavior of a well-defined system of gelling colloidal silica and how this behavior may be understood from a simple theoretical model which incorporates the microstructure of the gel. The ultra-small angle neutron scattering (USANS) technique is used to interrogate structure during the gelation process. The investigations focused on a system where both particles and interactions are well-defined: 7 nm silica particle acid-treated aqueous solution subjected to a constant applied shear in Couette geometry. Ultra-small angle neutron scattering (USANS) time-dependent scattering intensities were measured at wave vectors, q, in the range, 1.0 × 10 The first recorded direct kinetic measurements of the micron-scale structure in a gelling system. A critical micro-structural feature of the intensity-viscosity time behavior of a gelling colloid subjected to a shear is the cluster size. A viscosity/intensity coupling observed at the time of a viscosity maximum that corresponds to a time-dependent critical stress and speculated to be independent of the wave vector over a wide q-range.
Characterization of red-shifted phycobilisomes isolated from the chlorophyll f-containing cyanobacterium Halomicronema hongdechloris
Publisher: Elsevier BV
Date: 2016
DOI: 10.1016/J.BBABIO.2015.10.009
Abstract: Phycobilisomes are the main light-harvesting protein complexes in cyanobacteria and some algae. It is commonly accepted that these complexes only absorb green and orange light, complementing chlorophyll absorbance. Here, we present a new phycobilisome derived complex that consists only of allophycocyanin core subunits, having red-shifted absorption peaks of 653 and 712 nm. These red-shifted phycobiliprotein complexes were isolated from the chlorophyll f-containing cyanobacterium, Halomicronema hongdechloris, grown under monochromatic 730 nm-wavelength (far-red) light. The 3D model obtained from single particle analysis reveals a double disk assembly of 120-145 Å with two α/β allophycocyanin trimers fitting into the two separated disks. They are significantly smaller than typical phycobilisomes formed from allophycocyanin subunits and core-membrane linker proteins, which fit well with a reduced distance between thylakoid membranes observed from cells grown under far-red light. Spectral analysis of the dissociated and denatured phycobiliprotein complexes grown under both these light conditions shows that the same bilin chromophore, phycocyanobilin, is exclusively used. Our findings show that red-shifted phycobilisomes are required for assisting efficient far-red light harvesting. Their discovery provides new insights into the molecular mechanisms of light harvesting under extreme conditions for photosynthesis, as well as the strategies involved in flexible chromatic acclimation to erse light conditions.
Photoswitchable Janus glycodendrimer micelles as multivalent inhibitors of LecA and LecB from Pseudomonas aeruginosa
Publisher: Elsevier BV
Date: 11-2017
DOI: 10.1016/J.COLSURFB.2017.08.016
Abstract: The first ex le of the self-assembly and lectin binding properties of photoswitchable glycodendrimer micelles is reported. Light-addressable micelles were assembled from a library of 12 hiphilic Janus glycodendrimers composed of variable carbohydrate head groups and hydrophobic tail groups linked to an azobenzene core. Spontaneous association in water gave cylindrical micelles with uniform size distribution as determined by dynamic light scattering (DLS) and small angle neutron scattering (SANS). Trans-cis photoisomerization of the azobenzene dendrimer core was used to probe the self-assembly behaviour and lectin binding properties of cylindrical micelles, revealing moderate-to-potent inhibition of lectins LecA and LecB from Pseudomonas aeruginosa.
Effects of Sugars on Lipid Bilayers during Dehydration - SAXS/WAXS Measurements and Quantitative Model
Publisher: American Chemical Society (ACS)
Date: 03-02-2009
DOI: 10.1021/JP808670T
Abstract: We present an X-ray scattering study of the effects of dehydration on the bilayer and chain-chain repeat spacings of dipalmitoylphosphatidylcholine bilayers in the presence of sugars. The presence of sugars has no effect on the average spacing between the phospholipid chains in either the fluid or gel phase. Using this finding, we establish that for low sugar concentrations only a small amount of sugar exclusion occurs. Under these conditions, the effects of sugars on the membrane transition temperatures can be explained quantitatively by the reduction in hydration repulsion between bilayers due to the presence of the sugars. Specific bonding of sugars to lipid headgroups is not required to explain this effect.
The morphology of crystallisation of PHBV/PHBV copolymer blends
Publisher: Elsevier BV
Date: 03-2019
Phase dependent structural perturbation of a robust multicomponent assembled icosahedral array
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8CC05650A
Abstract: p -Sulfonatocalix[4]arene, dipicolinate and yttrium( iii ) ions self assemble into a robust distorted or regular icosahedral array in the solid and solution states respectively.
Direct Comparison of Disaccharide Interaction with Lipid Membranes at Reduced Hydrations
Publisher: American Chemical Society (ACS)
Date: 11-08-2015
DOI: 10.1021/ACS.LANGMUIR.5B02127
Abstract: Understanding sugar-lipid interactions during desiccation and freezing is an important step in the elucidation of cryo- and anhydro-protection mechanisms. We determine sucrose, trehalose, and water concentration distributions in intra-bilayer volumes between opposing dioleoylphosphatidylcholine bilayers over a range of reduced hydrations and sugar concentrations. Stacked lipid bilayers at reduced hydration provide a suitable system to mimic environmental dehydration effects, as well as a suitable system for direct probing of sugar locations by neutron membrane diffraction. Sugar distributions show that sucrose and trehalose both behave as typical uncharged solutes, largely excluded from the lipid bilayers regardless of sugar identity, and with no correlation between sugar distribution and the lipid headgroup position as the hydration is changed. These results are discussed in terms of current opinions about cryo- and anhydro-protection mechanisms.
Insights into Free Volume Variations across Ion-Exchange Membranes upon Mixed Solvents Uptake by Small and Ultrasmall Angle Neutron Scattering
Publisher: American Chemical Society (ACS)
Date: 02-03-2017
Abstract: Ion-exchange membranes are composite separation materials increasingly used in a variety of electro-membranes and electrochemical processes. Although promising for solvent reclamation, to date, their main applications are limited to aqueous environments due to physicochemical and microstructural changes of the materials upon exposure to nonaqueous and mixed solvents solutions, affecting long-term stability and separation performance. In the present work, the structural changes of commercial and novel hybrid ion-exchange membranes in mixed methanol/water and ethanol/water solutions are assessed for the first time using ultra- and small-angle neutron scattering techniques. The interface between the ion-exchange functional layer and the mechanical support of the membranes is evaluated in the ultralow-q region, while a broad solvent-dependent peak at the mid-q region was correlated to the microstructural properties which are related to the free volume across the ion-exchange domains and to the materials electrical and nanoscale mechanical properties. The results of this study may offer new opportunities toward the development of an efficient separation process using ion-exchange membranes for the purification of fermentation broths toward biofuel generation.
The hydration of paper studied with solid-state magnetisation-exchange 1H NMR spectroscopy
Publisher: Walter de Gruyter GmbH
Date: 07-2006
DOI: 10.1515/HF.2006.064
Abstract: The wide-line 1 H nuclear magnetic resonance (NMR) spectrum of paper in equilibrium with ambient humidity consists of super-imposed relatively broad and narrow lines. The narrower line is of the order of 2 kHz wide at half the maximum height, while the broader line is of the order of 40 kHz in width at half height. On the basis of these line widths, the narrow line is assigned to water sorbed to the paper, and the broad line to the polymeric constituents of the paper. It was not possible to distinguish between the various polymeric components of paper contributing to the 1 H NMR spectra. A modified Goldman-Shen pulse sequence was used to generate a spatial magnetisation gradient between the polymer and water phases. The exchange of magnetisation between protons associated with water and those associated with the macromolecules in paper was observed. The exchange of magnetisation is discussed within a heat transfer model for homonuclear dipolar coupling, with exchange being characterised by a spin-diffusion coefficient. Consideration of the magnitude of the initial rate of the exchange process and estimates of the spin-spin relaxation times based on 1 H line widths indicate that some water must exist in a sufficiently immobile state as to allow homonuclear dipolar interactions between adjacent polymer and water protons. Thus, water sorbed onto paper must exist in at least two states in mass exchange with each other. This observation allows certain conclusions to be drawn about the ratio of free/bound water as a function of moisture content and the dispersal of water within the polymer matrix.
Phase separation in a ternary DPPC/DOPC/POPC system with reducing hydration
Publisher: Elsevier BV
Date: 05-2023
Aqueous hydrogen peroxide-induced degradation of polyolefins: A greener process for controlled-rheology polypropylene
Publisher: Elsevier BV
Date: 07-2015
Identification of shared risk loci and pathways for bipolar disorder and schizophrenia
Publisher: Public Library of Science (PLoS)
Date: 06-02-2017
Thermal fluctuations of haemoglobin from different species: adaptation to temperature via conformational dynamics
Publisher: The Royal Society
Date: 13-06-2012
Abstract: Thermodynamic stability, configurational motions and internal forces of haemoglobin (Hb) of three endotherms (platypus, Ornithorhynchus anatinus domestic chicken, Gallus gallus domesticus and human, Homo sapiens ) and an ectotherm (salt water crocodile, Crocodylus porosus ) were investigated using circular dichroism, incoherent elastic neutron scattering and coarse-grained Brownian dynamics simulations. The experimental results from Hb solutions revealed a direct correlation between protein resilience, melting temperature and average body temperature of the different species on the 0.1 ns time scale. Molecular forces appeared to be adapted to permit conformational fluctuations with a root mean square displacement close to 1.2 Å at the corresponding average body temperature of the endotherms. Strong forces within crocodile Hb maintain the litudes of motion within a narrow limit over the entire temperature range in which the animal lives. In fully hydrated powder s les of human and chicken, Hb mean square displacements and effective force constants on the 1 ns time scale showed no differences over the whole temperature range from 10 to 300 K, in contrast to the solution case. A complementary result of the study, therefore, is that one hydration layer is not sufficient to activate all conformational fluctuations of Hb in the pico- to nanosecond time scale which might be relevant for biological function. Coarse-grained Brownian dynamics simulations permitted to explore residue-specific effects. They indicated that temperature sensing of human and chicken Hb occurs mainly at residues lining internal cavities in the β-subunits.
Drug-Directed Morphology Changes in Polymerization-Induced Self-Assembly (PISA) Influence the Biological Behavior of Nanoparticles
Publisher: American Chemical Society (ACS)
Date: 09-06-2020
The effect of comonomer concentration and distribution on the photo-oxidative degradation of linear low density polyethylene films
Publisher: Elsevier BV
Date: 06-2017
Synthesis and characterisation of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) multi-block copolymers comprising blocks of differing 3-hydroxyvalerate contents
Publisher: Elsevier BV
Date: 11-2023
QUOKKA, the pinhole small-angle neutron scattering instrument at the OPAL Research Reactor, Australia: design, performance, operation and scientific highlights
Publisher: International Union of Crystallography (IUCr)
Date: 20-03-2018
DOI: 10.1107/S1600576718002534
Abstract: QUOKKA is a 40 m pinhole small-angle neutron scattering instrument in routine user operation at the OPAL research reactor at the Australian Nuclear Science and Technology Organisation. Operating with a neutron velocity selector enabling variable wavelength, QUOKKA has an adjustable collimation system providing source–s le distances of up to 20 m. Following the large-area s le position, a two-dimensional 1 m 2 position-sensitive detector measures neutrons scattered from the s le over a secondary flight path of up to 20 m. Also offering incident beam polarization and analysis capability as well as lens focusing optics, QUOKKA has been designed as a general purpose SANS instrument to conduct research across a broad range of scientific disciplines, from structural biology to magnetism. As it has recently generated its first 100 publications through serving the needs of the domestic and international user communities, it is timely to detail a description of its as-built design, performance and operation as well as its scientific highlights. Scientific ex les presented here reflect the Australian context, as do the industrial applications, many combined with innovative and unique s le environments.
Correction: Non-reversible heat-induced gelation of a biocompatible Fmoc-hexapeptide in water
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0NR90160A
Abstract: Correction for ‘Non-reversible heat-induced gelation of a biocompatible Fmoc-hexapeptide in water’ by Jonathan P. Wojciechowski et al. , Nanoscale , 2020, 12 , 8262–8267, DOI: 10.1039/D0NR00289E.
Measurement of glucose exclusion from the fully hydrated DOPE inverse hexagonal phase
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/B919086D
Assembly of nanoparticles-polyelectrolyte complexes in nanofiber cellulose structures
Publisher: Elsevier BV
Date: 2017
Effect of red blood cell shape changes on haemoglobin interactions and dynamics: a neutron scattering study
Publisher: The Royal Society
Date: 10-2020
DOI: 10.1098/RSOS.201507
Abstract: By using a combination of experimental neutron scattering techniques, it is possible to obtain a statistical perspective on red blood cell (RBC) shape in suspensions, and the inter-relationship with protein interactions and dynamics inside the confinement of the cell membrane. In this study, we examined the ultrastructure of RBC and protein–protein interactions of haemoglobin (Hb) in them using ultra-small-angle neutron scattering and small-angle neutron scattering (SANS). In addition, we used the neutron backscattering method to access Hb motion on the ns time scale and Å length scale. Quasi-elastic neutron scattering (QENS) experiments were performed to measure diffusive motion of Hb in RBCs and in an RBC lysate. By using QENS, we probed both internal Hb dynamics and global protein diffusion, on the accessible time scale and length scale by QENS. Shape changes of RBCs and variation of intracellular Hb concentration were induced by addition of the Na + -selective ionophore monensin and the K + -selective one, valinomycin. The experimental SANS and QENS results are discussed within the framework of crowded protein solutions, where free motion of Hb is obstructed by mutual interactions.
H2O/D2O Contrast Variation for Ultra-Small-Angle Neutron Scattering to Minimize Multiple Scattering Effects of Colloidal Particle Suspensions
Publisher: MDPI AG
Date: 07-09-2018
Abstract: This study investigated the use of solvent contrast (H2O/D2O ratio) as a means to optimize the ultra-small-angle neutron scattering (USANS) signal. By optimizing the signal, it was possible to reduce the undesirable effects of coherent multiple scattering while still maintaining a measurable scattered intensity. This result will further enable the use of USANS as a probe of the interactions between colloidal particles and their structures within concentrated suspensions as well as particle dispersion/aggregation. As a model system, we prepared silica colloidal particle suspensions at different solid concentrations. USANS curves were measured using the classical Bonse–Hart double crystal diffractometer while varying the scattering length density of the aqueous phase, thus varying the contrast to the silica particles. As a means of assessing the impact of multiple scattering effects on different q-values, we analyzed the scattered intensity at different contrasts at three different q values. The data were then used to determine the match point of the silica particle suspensions from the expected square root dependence of the scattered intensity with solvent composition, to analyze any differences associated with the solid concentration change, and to determine the optimum H2O/D2O ratio in terms of high transmission (TSAS 80%) and high enough scattering intensity associated with the contrast of the system. Through this investigation series, we confirmed that adjusting the contrast of the solvent (H2O/D2O) is a good methodology to reduce multiple scattering while maintaining a strong enough scattering signal from a concentrated suspension of silica particles for both USANS and rheometric USANS (rheo-USANS) experiments.
USANS study of wood structure
Publisher: Elsevier BV
Date: 11-2006
Evolution of structural dimensions in mesoporous template precursor from hexagonal lyotropic liquid crystals
Publisher: IOP Publishing
Date: 12-11-2020
Controlling self-assembly of diphenylalanine peptides at high pH using heterocyclic capping groups
Publisher: Springer Science and Business Media LLC
Date: 08-03-2017
DOI: 10.1038/SREP43947
Abstract: Using small angle neutron scattering (SANS), it is shown that the existence of pre-assembled structures at high pH for a capped diphenylalanine hydrogel is controlled by the selection of N-terminal heterocyclic capping group, namely indole or carbazole. At high pH, changing from a somewhat hydrophilic indole capping group to a more hydrophobic carbazole capping group results in a shift from a high proportion of monomers to self-assembled fibers or wormlike micelles. The presence of these different self-assembled structures at high pH is confirmed through NMR and circular dichroism spectroscopy, scanning probe microscopy and cryogenic transmission electron microscopy.
Biopolymer Deuteration for Neutron Scattering and Other Isotope-Sensitive Techniques
Publisher: Elsevier
Date: 2015
DOI: 10.1016/BS.MIE.2015.06.015
Abstract: The use of microbial biosynthesis to produced deuterated recombinant proteins is a well-established practice in investigations of the relationship between molecular structure and function using neutron scattering and nuclear magnetic resonance spectroscopy. However, there have been few reports of using microbial synthetic capacity to produce labeled native biopolymers. Here, we describe methods for the production of deuterated polyhydroxyalkanoate biopolyesters in bacteria, the polysaccharide chitosan in the yeast Pichia pastoris, and cellulose in the bacterium Gluconacetobacter xylinus. The resulting molecules offer not only multiple options in creating structural contrast in polymer blends and composites in structural studies but also insight into the biosynthetic pathways themselves.
Effect of Polymer Chain Density on Protein-Polymer Conjugate Conformation
Publisher: American Chemical Society (ACS)
Date: 04-2019
DOI: 10.1021/ACS.BIOMAC.9B00184
Abstract: Many biomedical applications employ covalent attachment to synthetic polymers to enhance the efficiency of proteins or other therapeutically active molecules. We report here the impact of polymer conjugation on the structural and thermal stability of a protein model, the bovine serum albumin, using a variable number of linear biodegradable polyphosphoesters, which were covalently tethered to the protein. We observed that BSA's secondary structure measured by circular dichroism is independent of the conjugation. Small-angle neutron scattering, however, reveals a change from ellipsoid to globular shape of the whole complex arising from a slight compaction of the protein core and an increase of the polymer's radius of gyration as a function of the grafting polymer density. In particular, we highlight a gradual change of the polymer conformation around the protein and elongation of the semimajor dimension of the ellipsoidal protein. Our results will contribute to the description of biophysical characteristics of a new class of biologically relevant protein-polymer conjugates.
Structural Studies of Three-Arm Star Block Copolymers Exposed to Extreme Stretch Suggests a Persistent Polymer Tube
Publisher: American Physical Society (APS)
Date: 16-05-2018
Importance of Polymer Length in Fructose-Based Polymeric Micelles for an Enhanced Biological Activity
Publisher: American Chemical Society (ACS)
Date: 10-01-2019
On the Interpretation of X‐Ray Diffraction Powder Patterns in Terms of the Nanostructure of Cellulose I Fibres
Publisher: Wiley
Date: 29-07-2005
Decoupling order and conductivity in doped conducting polymers
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6CP03307E
Abstract: The resistance of pEDOT films manufactured by vapour phase polymerisation and conventional casting of oxidant and monomer displays an increase in resistance when undergoing a transition from the disordered state of the film to an ordered state in the same film.
Protein-Eye View of the in Meso Crystallization Mechanism
Publisher: American Chemical Society (ACS)
Date: 12-06-2019
DOI: 10.1021/ACS.LANGMUIR.9B00647
Abstract: For evolving biological and biomedical applications of hybrid protein?lipid materials, understanding the behavior of the protein within the lipid mesophase is crucial. After more than two decades since the invention of the in meso crystallization method, a protein-eye view of its mechanism is still lacking. Numerous structural studies have suggested that integral membrane proteins preferentially partition at localized flat points on the bilayer surface of the cubic phase with crystal growth occurring from a local fluid lamellar L
Small angle scattering in the Porod region from hydrated paper sheets at varying humidities
Publisher: Walter de Gruyter GmbH
Date: 08-2004
DOI: 10.1515/HF.2004.071
Abstract: The microscopic changes in the structure of paper at different equilibrium moisture contents were examined using the novel technique of contrast variation small angle neutron scattering (SANS). Contrast variation, by appropriate selection of the H 2 O:D 2 O ratio, was used to simplify the scattering from hydrated paper to a two-phase approximation. The two phases were paper polymers (cellulose, lignin and hemicelluloses) and a phase consisting of water and voids. The two-phase approximation is justified by consideration of the chemistry and density of each of the polymer species belonging to paper, and by matching the scattering length density of the sorbed moisture to air. The neutron intensity at the higher scattering angles examined was successfully fitted using the Porod law, which is applicable to scattering from a two-phase system at the high scattering angle limit. This limit is related to the specific surface area between the two phases. The limiting scattered intensity of neutrons was found to increase with increasing moisture content for a range of paper materials. It is concluded that the sorption of water increased the limiting intensity because water disrupted polymer-polymer bonding. The Porod law also predicts the slope of the intensity/scattering angle curve at the high scattering angle limit.
Three-Dimensional Organization of Self-Encapsulating Gluconobacter oxydans Bacterial Cells
Publisher: American Chemical Society (ACS)
Date: 20-11-2017
Bactericidal activity of self-assembled palmitic and stearic fatty acid crystals on highly ordered pyrolytic graphite
Publisher: Elsevier BV
Date: 09-2017
DOI: 10.1016/J.ACTBIO.2017.07.004
Abstract: The wings of insects such as cicadas and dragonflies have been found to possess nanostructure arrays that are assembled from fatty acids. These arrays can physically interact with the bacterial cell membranes, leading to the death of the cell. Such mechanobactericidal surfaces are of significant interest, as they can kill bacteria without the need for antibacterial chemicals. Here, we report on the bactericidal effect of two of the main lipid components of the insect wing epicuticle, palmitic (C16) and stearic (C18) fatty acids. Films of these fatty acids were re-crystallised on the surface of highly ordered pyrolytic graphite. It appeared that the presence of two additional CH Nanostructured cicada and dragonfly wing surfaces have been discovered to be able physically kill bacterial cells. Here, we report on the successful fabrication of bactericidal three-dimensional structures of two main lipid components of the epicuticle of insect wings, palmitic (C16) and stearic (C18) acids. After crystallisation onto highly ordered pyrolytic graphite, both the palmitic and stearic acid films displayed bactericidal activity against both Gram-negative Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus cells. The simplicity of the production of these microcrystallite interfaces suggests that a fabrication technique, based on solution deposition, could be an effective technique for the application of bactericidal nanocoatings.
Molecular-Scale Understanding of the Embrittlement in Polyethylene Ocean Debris
Publisher: American Chemical Society (ACS)
Date: 18-08-2020
Superhydrophobic and Superoleophilic Micro-Wrinkled Reduced Graphene Oxide as a Highly Portable and Recyclable Oil Sorbent
Publisher: American Chemical Society (ACS)
Date: 12-04-2016
Abstract: The potential of superhydrophobic and superoleophilic microwrinkled reduced graphene oxide (MWrGO) structures is here demonstrated for oil spill cleanup. The impact of the thickness of MWrGO films on the sorption performance of three different oils was investigated. Water contact angles across the MWrGO surfaces were found to exceed 150°, while oil could be easily absorbed by the microwrinkled structures of MWrGO within seconds after contact. Although the oil surface diffusion rate was not found to be dependent on the thickness of the graphene oxide films, the oil sorption capacity was the largest with the thinner MWrGO films due to the high surface area resulting from their fine surface texture. Furthermore, the composite films can be repeatedly used for at least 20 oil sorption-removal cycles without any notable loss in selectivity and uptake capacity. These MWrGO/elastomer composite films could be applied as a potential candidate material for future oil spill cleanup.
Using SANS with Contrast-Matched Lipid Bicontinuous Cubic Phases To Determine the Location of Encapsulated Peptides, Proteins, and Other Biomolecules
Publisher: American Chemical Society (ACS)
Date: 14-07-2016
DOI: 10.1021/ACS.JPCLETT.6B01173
Abstract: An understanding of the location of peptides, proteins, and other biomolecules within the bicontinuous cubic phase is crucial for understanding and evolving biological and biomedical applications of these hybrid biomolecule-lipid materials, including during in meso crystallization and drug delivery. While theoretical modeling has indicated that proteins and additive lipids might phase separate locally and adopt a preferred location in the cubic phase, this has never been experimentally confirmed. We have demonstrated that perfectly contrast-matched cubic phases in D2O can be studied using small-angle neutron scattering by mixing fully deuterated and hydrogenated lipid at an appropriate ratio. The model transmembrane peptide WALP21 showed no preferential location in the membrane of the diamond cubic phase of phytanoyl monoethanolamide and was not incorporated in the gyroid cubic phase. While deuteration had a small effect on the phase behavior of the cubic phase forming lipids, the changes did not significantly affect our results.
High and Stable Ionic Conductivity in 2D Nanofluidic Ion Channels between Boron Nitride Layers
Publisher: American Chemical Society (ACS)
Date: 05-2017
DOI: 10.1021/JACS.6B11100
Abstract: Achieving a high rate of ionic transport through porous membranes and ionic channels is important in numerous applications ranging from energy storage to water desalination, but it still remains a challenge. Herein we show that ions can quickly pass through interlayer spaces in hydrated boron nitride (BN) membranes. Measurements of surface-charge governed ionic currents between BN nanosheets in a variety of salt solutions (KCl, NaCl and CaCl
Co-assembly of helical β3-peptides: a self-assembled analogue of a statistical copolymer
Publisher: Walter de Gruyter GmbH
Date: 26-09-2017
Abstract: Unnatural peptide self-assembly offers the means to design hierarchical nanostructures of controlled geometries, chemical function and physical properties. N-acyl β 3 peptides, where all residues are unnatural amino acids, are able to form helical fibrous structures by a head-to-tail assembly of helical monomers, extending the helix via a three point supramolecular hydrogen bonding motif. These helical nanorods were shown to be stable under a wide range of physical conditions, offering a self-assembled analogue of polymeric fibres. Hitherto the self-assembly has only been demonstrated between identical monomers however the self-assembly motif is sequence-independent, offering the possibility of hetero-assembly of different peptide monomers. Here we present a proof of principle study of head-to-tail co-assembly of two different helical unnatural peptides Ac-β 3 [WELWEL] and Ac-β 3 [LIA], where the letters denote the β 3 analogues of natural amino acids. By atomic force microscopy imaging it was demonstrated that the homo-assembly and co-assembly of these peptides yield characteristically different structures. Synchrotron small angle X-ray scattering experiments have confirmed the presence of the fibres in the solution and the averaged diameters from modelled data correlate well to the results of AFM imaging. Hence, there is evidence of co-assembly of the fibrous superstructures given that different monomers may be used to introduce variations into chemical and physical properties, the results demonstrate a self-assembled analogue of a statistical co-polymer that can be used in designing complex functional nanomaterials.
Impact of Headgroup Asymmetry and Protonation State on the Aggregation Behavior of a New Type of Glycerol Diether Bolalipid
Publisher: American Chemical Society (ACS)
Date: 20-03-2018
DOI: 10.1021/ACS.LANGMUIR.8B00527
Abstract: In the present work, we describe the synthesis and the temperature-dependent aggregation behavior of a new class of asymmetrical glycerol diether bolalipids. These bolalipids are composed of a membrane-spanning alkyl chain with 32 carbon atoms (C32) in the sn-3 position, a methyl-branched C16 alkyl chain in the sn-2 position, and a zwitterionic phosphocholine headgroup in the sn-1 position of a glycerol moiety. The long C32 alkyl chain is terminated either by a second phosphocholine (PC-Gly(2C16Me)C32-PC) or by a phosphodimethylethanolamine headgroup (PC-Gly(2C16Me)C32-Me
Coordination crosslinking of helical substituted oligoamide nanorods with Cu(II)
Publisher: Informa UK Limited
Date: 18-02-2020
Moisture-activated dynamics on crystallite surfaces in cellulose
Publisher: Springer Science and Business Media LLC
Date: 24-01-2019
A fundamental study on photo-oxidative degradation of linear low density polyethylene films at embrittlement
Publisher: Elsevier BV
Date: 05-2012
Localisation of alkaline phosphatase in the pore structure of paper
Publisher: Springer Science and Business Media LLC
Date: 03-03-2017
Shrinkage induced stretchable micro-wrinkled reduced graphene oxide composite with recoverable conductivity
Publisher: Elsevier BV
Date: 11-2015
85. Sugar distribution between and around membranes during dehydration
Publisher: Elsevier BV
Date: 12-2006
The effects of alkylammonium counterions on the aggregation of fluorinated surfactants and surfactant ionic liquids
Publisher: Elsevier BV
Date: 08-2016
DOI: 10.1016/J.JCIS.2016.04.039
Abstract: The effects of organic counterions with varying carbon number on surfactant aggregation have been analysed by coupling perfluorooctanoate surfactant anions with various alkylammonium counterions. Both the degree of substitution (primary to tertiary) and alkyl chain length (0-3 carbons) of the counterions were varied to provide a comprehensive matrix of geometries and lipophilicities. Surface activity was measured using pendant drop tensiometry, while temperature-controlled small-angle neutron scattering was used to probe changes in aggregation morphology. It was found that the use of such alkylammonium counterions resulted in a strong preference for bilayer formation even at low surfactant concentration (<2wt%), when compared to simple inorganic counterions such as sodium which favour near-spherical micelles. At increased temperatures, some counterions led to unique phase behaviour wherein a transition between two structurally different lamellar phases is seen, rationalised as a transition into a microscopic phase separation wherein a surfactant-rich lamellar phase coexists with a dilute micellar phase. The results indicate that aggregation is controlled by a delicate balance of counterion size, hydrophilicity and diffuseness of charge, providing new methods for the subtle control of surfactant solutions.
Just add sugar for carbohydrate induced self-assembly of curcumin
Publisher: Springer Science and Business Media LLC
Date: 04-02-2019
DOI: 10.1038/S41467-019-08402-Y
Abstract: In nature, self-assembly processes based on hiphilic molecules play an integral part in the design of structures of higher order such as cells. Among them, hiphilic glycoproteins or glycolipids take on a pivotal role due to their bioactivity. Here we show that sugars, in particular, fructose, are capable of directing the self-assembly of highly insoluble curcumin resulting in the formation of well-defined capsules based on non-covalent forces. Simply by mixing an aqueous solution of fructose and curcumin in an open vessel leads to the generation of capsules with sizes ranging between 100 and 150 nm independent of the initial concentrations used. Our results demonstrate that hydrogen bonding displayed by fructose can induce the self-assembly of hydrophobic molecules such as curcumin into well-ordered structures, and serving as a simple and virtually instantaneous way of making nanoparticles from curcumin in water with the potential for template polymerization and nanocarriers.
Aggregation behaviour of a single-chain, phenylene-modified bolalipid and its miscibility with classical phospholipids
Publisher: Beilstein Institut
Date: 23-05-2017
DOI: 10.3762/BJOC.13.99
Abstract: In the present work, we describe the synthesis of a single-chain, phenylene-modified bolalipid with two phosphocholine headgroups, PC-C18pPhC18-PC, using a Sonogashira cross-coupling reaction as a key step. The aggregation behaviour was studied as a function of temperature using transmission electron microscopy (TEM), differential scanning calorimetry (DSC), Fourier-transform infrared (FTIR) spectroscopy, and small angle neutron scattering (SANS). We show that our new bolalipid self-assembles into nanofibres, which transform into flexible nanofibres at 27 °C and further to small elongated micelles at 45 °C. Furthermore, the miscibility of the bolalipid with bilayer-forming phosphatidylcholines (DMPC, DPPC, and DSPC) was investigated by means of DSC, TEM, FTIR, and small angle X-ray scattering (SAXS). We could show that the PC-C18pPhC18-PC is partially miscible with saturated phosphatidylcholines however, closed lipid vesicles with an increased thermal stability were not found. Instead, bilayer fragments and disk-like aggregates are formed.
Manipulating three-dimensional gel network entanglement by thin film shearing
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6CC00171H
Abstract: A novel method of combining thin-film shearing with SANS resulted in complete disruption of 3-D network of fluorous bis-urea gel. In contrast, non-fluorinated analogue undergoes partial disruption which emphasizes the resistance of non-fluorous bis-urea gelators towards shear.
Kinetics of the lamellar gel-fluid transition in phosphatidylcholine membranes in the presence of sugars
Publisher: Elsevier BV
Date: 02-2010
DOI: 10.1016/J.CHEMPHYSLIP.2009.12.001
Abstract: Phase diagrams are presented for dipalmitoylphosphatidylcholine (DPPC) in the presence of sugars (sucrose) over a wide range of relative humidities (RHs). The phase information presented here, determined by small angle X-ray scattering (SAXS), is shown to be consistent with previous results achieved by differential scanning calorimetry (DSC). Both techniques show a significant effect of sucrose concentration on the phase behaviour of this phospholipid bilayer. An experimental investigation into the effect of sugars on the kinetic behaviour of the gel to fluid transition is also presented showing that increasing the sugar content appears to slightly increase the rate at which the transition occurs.
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