ORCID Profile
0000-0003-1944-5897
Current Organisations
Fonterra Research and Development Centre
,
Bar-Ilan University
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Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1LC00601K
Abstract: Automated microfluidics, laser tweezers, particle detection for pairwise particle stickiness measurements.
Publisher: JMIR Publications Inc.
Date: 23-05-2018
Abstract: ecal occult blood tests (FOBTs) are recommended by the US Preventive Services Task Force as a screening method for colorectal cancer (CRC), but they are only effective if positive results are followed by colonoscopy. Surprisingly, a large proportion of patients with a positive result do not follow this recommendation. he objective of this study was to examine the effectiveness of text messaging (short message service, SMS) in increasing adherence to colonoscopy follow-up after a positive FOBT result. his randomized controlled trial was conducted with patients who had positive CRC screening results. Randomization was stratified by residential district and socioeconomic status (SES). Subjects in the control group (n=238) received routine care that included an alert to the physician regarding the positive FOBT result. The intervention group (n=232) received routine care and 3 text messaging SMS reminders to visit their primary care physician. Adherence to colonoscopy was measured 120 days from the positive result. All patient information, including test results and colonoscopy completion, were obtained from their electronic medical records. Physicians of study patients completed an attitude survey regarding FOBT as a screening test for CRC. Intervention and control group variables (dependent and independent) were compared using chi-square test. Logistic regression was used to calculate odds ratios (ORs) and 95% CIs for performing colonoscopy within 120 days for the intervention group compared with the control group while adjusting for potential confounders including age, gender, SES, district, ethnicity, and physicians’ attitude. verall, 163 of the 232 patients in the intervention group and 112 of the 238 patients in the control group underwent colonoscopy within 120 days of the positive FOBT results (70.3% vs 47.1% OR 2.17, 95% CI 1.49-3.17 P .001) this association remained significant after adjusting for potential confounders (P=.001). text message (SMS) reminder is an effective, simple, and inexpensive method for improving adherence among patients with positive colorectal screening results. This type of intervention could also be evaluated for other types of screening tests. linicalTrials.gov NCT03642652 t2/show/NCT03642652 (Archived by WebCite at 4TlICijl)
Publisher: American Chemical Society (ACS)
Date: 18-11-2004
DOI: 10.1021/LA047978K
Publisher: Elsevier BV
Date: 05-2014
Publisher: Elsevier BV
Date: 08-2015
Publisher: Elsevier BV
Date: 11-2016
Publisher: Elsevier BV
Date: 05-2004
Publisher: American Chemical Society (ACS)
Date: 21-05-2005
DOI: 10.1021/LA050226L
Abstract: The colloid probe technique was used to investigate the interactions between in idual zinc sulfide (ZnS) microspheres and an air bubble in electrolyte solution. Incorporation of zinc ions into the electrolyte solution overcomes the disproportionate zinc ion dissolution and mimics high-volume-fraction conditions common in flotation. Determined interaction forces revealed a distinct lack of long-ranged hydrophobic forces, indicated by the presence of a DLVO repulsion prior to particle engulfment. Single microsphere contact angles were determined from particle-bubble interactions. Contact angles increased with decreasing radii and with surface oxidation. Surface modification by the absorption of copper and subsequently potassium O-ethyldithiocarbonate (KED) reduced repulsive forces and strongly increased contact angles.
Publisher: Elsevier BV
Date: 09-2017
Publisher: Springer Science and Business Media LLC
Date: 13-06-2018
Publisher: Elsevier BV
Date: 2015
Publisher: Elsevier BV
Date: 2023
DOI: 10.1016/J.JCIS.2022.10.069
Abstract: Dairy proteins and mono- and diglycerides (MDG) are often used in unison to tailor the properties of dairy-based emulsions. However, there are significant gaps in our understanding of how proteins affect lipid crystallisation at the oil-water interface. We have used a unique combination of interfacially-sensitive techniques to elucidate the impact of dairy proteins on interfacial MDG crystal formation. The formation temperature of interfacial MDG crystals was assessed through interfacial tension studies via drop shape analysis. Small and Wide-Angle X-ray Scattering measurements were performed on isolated oil-water interfaces, allowing for in-situ interrogation of MDG crystal structure and concentration at and near the interface. Dairy proteins are seen to reduce the temperature at which MDG crystals form at the oil-water interface. The displacement of proteins upon interfacial crystal formation was also clearly observed in interfacial tension measurements. For the first time, lipid crystals formed at the oil-water interface have been characterised using X-ray scattering. All scattering studies showed no change to the MDG crystal structures at the oil-water interface in the presence of adsorbed proteins. The results demonstrate that informed selection of emulsifier components is critical to controlling interfacial crystallisation with concomitant impact on emulsion stability.
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C0SM00779J
Publisher: Walter de Gruyter GmbH
Date: 2019
Abstract: The rheological and structural properties of cheese govern many physical processes associated with cheese such as slumping, slicing and melting. To date there is no quantitative model that predicts shear modulus, viscosity or any other rheological property across the entire range of cheeses only empirical fits that interpolate existing data. A lack of a comprehensive model is in part due to the many variables that can affect rheology such as salt, pH, calcium levels, protein to moisture ratio, age and temperature. By modelling the casein matrix as a series core-shell nano particles assembled from calcium and protein these variables can be reduced onto a simpler two-dimensional format consisting of attraction and equivalent hard sphere volume fraction. Approximating the interaction between core-shell nano particles with a Mie potential enables numerical predictions of shear moduli. More qualitatively, this two-dimensional picture can be applied quite broadly and captures the viscoelastic behaviour of soft and hard cheeses as well as their melting phenomena.
Publisher: Elsevier BV
Date: 12-2014
Publisher: Springer Science and Business Media LLC
Date: 03-11-2016
Publisher: Elsevier BV
Date: 03-2017
Publisher: CSIRO Publishing
Date: 2001
DOI: 10.1071/CH01117
Abstract: A summary is given of the authors’ recent research on viscoelastic theory and its application to colloid probe atomic force microscopy. A general computational approach for the interaction of viscoelastic colloids interacting with realistic surface forces of extended range is outlined, and the origins of velocity- and time-dependent effects including hysteresis are discussed. A general method for establishing the zero of separation in atomic force microscopy of deformable bodies is described and utilized in force measurements made on viscoelastic poly(dimethylsiloxane) colloid particles. A quantitative analysis of the velocity and load dependence of the hysteresis in the measurements yields the viscoelastic parameters of the colloid.
Publisher: American Chemical Society (ACS)
Date: 30-11-2018
Publisher: American Chemical Society (ACS)
Date: 02-11-2005
DOI: 10.1021/LA052354F
Abstract: A simple procedure to synthesize gold nanowires based on the reduction of hydrogen tetrachloroaurate by 2-mercaptosuccinic acid in aqueous solution is presented. This procedure requires no additional capping or reduction agent and produces wires with an apparent curly morphology several micrometers in length with diameters as thin as 15 nm. Some of the wires produced end in a ribbonlike structure, finally terminated by a flat triangular prism. Investigations by scanning electron microscopy, transmission electron microscopy (bright and dark field), scanning transmission electron microscopy, and atomic force microscopy as well as conductivity measurements indicate fully connected, polycrystalline gold objects.
Publisher: American Chemical Society (ACS)
Date: 28-04-2007
DOI: 10.1021/JP069009Z
Abstract: Charging behavior and colloidal stability of amidine latex particles are studied in the presence of poly(sodium styrene sulfonate) (PSS) and KCl. Detailed measurements of electrophoretic mobility, adsorbed layer thickness, and aggregation (or coagulation) rate constant on varying the polymer dose, molecular mass of the polymer, and ionic strength are reported. Polyelectrolyte adsorption leads to the characteristic charge reversal (or overcharging) of the colloidal particles at the isoelectric point (IEP). In accordance with classical Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, uncharged particles tend to aggregate because of van der Waals attraction, whereas charged particles are stabilized by electrical double layer repulsion. Attractive patch-charge interactions originating from the laterally inhomogeneous structure of the adsorbed polymer substantially decrease the suspension stability or even accelerate the aggregation rate beyond diffusion control. These electrostatic non-DLVO forces become progressively important with increasing molecular mass of the polymer and the ionic strength of the solution. At higher polymer dose of typically 10 times the IEP, one observes the formation of a saturated layer of the adsorbed polymer with a thickness of several nanometers. Its thickness increases with increasing molecular mass, whereby the layer becomes increasingly porous. This layer does not seem to be involved in the suspension stabilization, since at such high polymer doses the double layer repulsion has attained sufficient strength to stabilize the suspension.
Publisher: Elsevier BV
Date: 05-2019
DOI: 10.1016/J.FOODCHEM.2018.11.136
Abstract: The hard milk fat (HMF) fraction of milk fat was isolated via dry, thermal fractionation, followed by a solvent washing process. The resulting HMF crystals were visibly free of entrapped liquid fat, and subsequently characterised by thermal analysis, X-ray diffraction, and electron microscopy. The HMF crystals were found to be mostly β' and β'
Publisher: Elsevier BV
Date: 07-2000
Publisher: Routledge
Date: 05-08-2016
Publisher: American Chemical Society (ACS)
Date: 08-02-2002
DOI: 10.1021/LA011461G
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9SM01137D
Abstract: The solid content of viscoelastic emulsion drops is known to affect their propensity for aggregation and their subsequent coalescence behaviour, where the balance between the drive to reduce surface tension and the straining of an internal viscoelastic network is able to create a plethora of stable partially-coalesced states. The latter has previously been elegantly demonstrated in synthetic systems, generated using oil containing different phase volumes of added solids, with micro-pipette experiments carried out on emulsion drops of several tens of microns in size. Herein we carry out experiments in the same spirit but aided by optical tweezers (OT) and using smaller micron-sized emulsion drops generated from milk fat. Given the size dependence of Brownian fluctuations and Laplace pressure the experimental investigation of these smaller drops is not necessarily a trivial extension of the previous work. The solid content of initially separated drops is controlled using a temperature-cycling regime in the s le preparation protocol, and subsequently the propensity for drops to remain joined or not after being brought into contact was examined. Aggregated pairs of drops were then subjected to an increase in temperature, either locally using a high-powered laser, or more globally using a custom-made Peltier temperature-controller. By heating to different degrees, the amount of fat crystals in the drops was able to be controlled, with progressively more compact partially-coalesced states, and eventually complete coalescence generated as the solid content was reduced. While in contrast to previous studies, the emulsion studied here was quite different in size and nature, and the solid content was controlled using temperature, the same underlying physics was nevertheless observed.
Publisher: American Chemical Society (ACS)
Date: 16-11-2005
DOI: 10.1021/LA0515120
Abstract: The repulsive forces between a glass sphere and immobilized colloidal droplets of poly(dimethylsiloxane) (PDMS) (with various levels of internal cross-linking) have been determined in aqueous solution using colloid probe atomic force microscopy. On initial surface approach, droplet deformation is negligible and interaction forces resemble those expected for electrical double layer interaction of rigid spheres. Upon further approach, droplet flattening results in forces that deviate below rigid body electrical double layer interaction. The extent of droplet deformation has been determined in terms of the deviation from hard-sphere interaction. Droplet deformability is strongly dependent on the droplet cross-linking level and hence controlled by some combination of the bulk rheological and interfacial properties of the droplets. Droplet nano-rheology has been determined from the extent of force curve hysteresis. For liquidlike droplets, with low levels of cross-linking, no force curve hysteresis is observed and the elastic deformation may be described by a single spring constant, which is controlled by the interfacial properties. For highly cross-linked droplets, the extent of deformation is controlled by the droplet's bulk rheology rather than the interfacial properties. Upon retraction of the surfaces, force curve hysteresis is observed and is due to the viscoelastic response of the PDMS. The extent of hysteresis is dependent on the rate of approach/retraction and the loading force and has been theoretically analyzed to determine nano-rheological parameters that describe droplet relaxation processes. Elastic moduli and relaxation times of the PDMS droplets vary over several orders of magnitude as a function of cross-linking.
Publisher: American Chemical Society (ACS)
Date: 09-11-2001
DOI: 10.1021/LA011136T
Publisher: Elsevier BV
Date: 11-2015
Publisher: Elsevier BV
Date: 06-2018
Publisher: JMIR Publications Inc.
Date: 05-02-2019
DOI: 10.2196/11114
Publisher: IOP Publishing
Date: 19-02-2005
Publisher: Elsevier BV
Date: 05-2023
Publisher: American Chemical Society (ACS)
Date: 11-02-2010
DOI: 10.1021/JP911482A
Abstract: The interaction forces between in idual positively charged amidine functionalized latex particles with adsorbed negatively charged sodium poly(styrene sulfonate) were studied with the colloidal probe technique based on atomic force microscopy (AFM). When the polymer dose is progressively increased, the strength of the repulsive force between the particles decreases as the charge neutralization point is approached, then increases again due to overcharging, and finally reaches a plateau. Surface potentials obtained from fits of the force profiles to Poisson-Boltzmann theory agree well with potentials measured with electrophoresis. Close to the charge neutralization point, attractive forces exceeding van der Waals interactions are found. These attractive forces increase in strength with increasing molecular mass of the polymer and decreasing ionic strength. These attractive interactions are of electrostatic origin and result from lateral patch-charge heterogeneities within the adsorbed polyelectrolyte layer. The measured forces are shown to be in semiquantitative agreement with model calculations based on charge distributions with square lattice symmetry.
Publisher: Routledge
Date: 17-05-2011
Publisher: Elsevier BV
Date: 10-2011
Publisher: Elsevier BV
Date: 06-2005
DOI: 10.1016/J.CIS.2004.08.003
Abstract: The essence of mineral flotation is the formation of strong particle-bubble aggregates. Hydrodynamics and DLVO forces hinder the particle-bubble approach, however the presence of a hydrophobic surface results in hydrophobic attraction and strong aggregate formation. In this article we review literature where the colloid probe technique has been used to investigate flotation, primarily particle-bubble interactions in aqueous solution. In some instance particles-bubble interactions have used to quantify the hydrophobic force, whilst hydrophobic forces are crucial for particle-bubble attachment, studies of hydrophobic forces are not the main focus of this article.
Publisher: American Chemical Society (ACS)
Date: 06-2009
DOI: 10.1021/JP904041K
Abstract: Polyelectrolytes adsorb strongly at oppositely charged surfaces, thereby dramatically influencing the corresponding interaction forces. In this letter, we report on direct force measurements with the atomic force microscope (AFM) between two in idual particles in an aqueous colloidal suspension in the presence of polyelectrolytes near the isoelectric point. From systematic variations of the molecular mass, the ionic strength, and analysis of adhesion events, we conclude that the observed attractive forces are mainly due to electrostatic patch-charge interactions. The same type of attractive forces is equally influencing interactions between proteins as well as hydrophobic or mineral surfaces.
Publisher: Elsevier BV
Date: 02-2022
DOI: 10.1016/J.JCIS.2021.11.008
Abstract: Dairy emulsions contain an intrinsically heterogeneous lipid phase, whose components undergo crystallisation in a manner that is critical to dairy product formulation, storage, and sensory perception. Further complexity is engendered by the erse array of interfacially-active molecules naturally present within the serum of dairy systems, and those that are added for specific formulation purposes, all of which interact at the lipid-serum interface and modify the impact of lipid crystals on dairy emulsion stability. The work described in this article addresses this complexity, with a specific focus on the impact of temperature cycling and the effect of emulsifier type on the formation and persistence of lipid crystals at lipid-solution interfaces. Profile analysis tensiometry experiments were performed using single droplets of the low melting fraction of dairy lipids, in the presence and absence of emulsifiers (Tween 80 and whey protein isolate, WPI) and during the temperature cycling, to study the formation of monoacylglycerol (MAG) crystals at the lipid-solution interface. Companion experiments on the same lipid systems, and at the same cooling and heating rates, were undertaken with synchrotron small angle X-ray scattering, to specifically analyse the effect of emulsifier type on the formation of triacylglycerol (TAG) crystals at the lipid-solution interface of a model dairy emulsion. These two complementary techniques have revealed that Tween 80 molecules delay MAG and TAG crystal formation by lowering the temperature at which the crystallisation occurs during two cooling cycles. WPI molecules delay the crystallisation of MAGs and TAGs during the first cooling cycle, while MAG crystals form without delay during the second cooling cycle at the same temperature as MAG crystals in an emulsifier free system. The crystallisation of TAGs is inhibited during the second cooling cycle. The observed differences in crystallisation behaviour at the interface upon temperature cycling can provide further insight into the impact of emulsifiers on the long-term stability of emulsion-based dairy systems during storage.
Publisher: Elsevier BV
Date: 05-2017
Location: Switzerland
Start Date: 2016
End Date: 2018
Funder: Australian Research Council
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