ORCID Profile
0000-0003-0309-1772
Current Organisation
University of South Australia
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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)
Mineral Processing/Beneficiation | Materials engineering | Applied Mathematics | Reaction kinetics and dynamics | Colloid and Surface Chemistry | Control Systems, Robotics and Automation | Applied Mathematics not elsewhere classified | Physical Chemistry (Incl. Structural) | Electrical and Electronic Engineering | Materials Engineering not elsewhere classified | Decision Support and Group Support Systems | Functional materials | Nanoscale characterisation | Resources Engineering and Extractive Metallurgy |
ANZSRC Socio-Economic Objective (SEO)
Energy Conservation and Efficiency not elsewhere classified | Processed Milk and Cream (incl. Powder, Evaporated and Condensed) | First Stage Treatment of Ores and Minerals not elsewhere classified | Expanding Knowledge in the Physical Sciences | Beneficiation or Dressing of Iron Ores | Mining and Extraction of Precious (Noble) Metal Ores | Concentrating Processes of Base Metal Ores (excl. Aluminium and Iron Ores) | Mining and Extraction of Copper Ores | Expanding Knowledge in the Mathematical Sciences
Related Links
Publications
Controlling Bubble–Solid Surface Interactions with Environmentally Benign Interfacial Modifiers
Publisher: American Chemical Society (ACS)
Date: 10-01-2019
Role of Surface Charge and Hydrophobicity in the Three-Phase Contact Formation and Wetting Film Stability under Dynamic Conditions
Publisher: American Chemical Society (ACS)
Date: 18-01-2012
DOI: 10.1021/JP211378S
Formation and tribology of fucoidan/chitosan polyelectrolyte multilayers on PDMS substrates
Publisher: Elsevier BV
Date: 12-2017
Carboxymethylcellulose Adsorption on Molybdenite: The Effect of Electrolyte Composition on Adsorption, Bubble-Surface Collisions, and Flotation
Publisher: American Chemical Society (ACS)
Date: 02-10-2014
DOI: 10.1021/LA503248E
Abstract: The adsorption of carboxymethylcellulose polymers on molybdenite was studied using spectroscopic ellipsometry and atomic force microscopy imaging with two polymers of differing degrees of carboxyl group substitution and at three different electrolyte conditions: 1 × 10(-2) M KCl, 2.76 × 10(-2) M KCl, and simulated flotation process water of multicomponent electrolyte content, with an ionic strength close to 2.76 × 10(-2) M. A higher degree of carboxyl substitution in the adsorbing polymer resulted in adsorbed layers that were thinner and with more patchy coverage increasing the ionic strength of the electrolyte resulted in increased polymer layer thickness and coverage. The use of simulated process water resulted in the largest layer thickness and coverage for both polymers. The effect of the adsorbed polymer layer on bubble-particle attachment was studied with single bubble-surface collision experiments recorded with high-speed video capture and image processing and also with single mineral molybdenite flotation tests. The carboxymethylcellulose polymer with a lower degree of substitution resulted in almost complete prevention of wetting film rupture at the molybdenite surface under all electrolyte conditions. The polymer with a higher degree of substitution prevented rupture only when adsorbed from simulated process water. Molecular kinetic theory was used to quantify the effect of the polymer on the dewetting dynamics for collisions that resulted in wetting film rupture. Flotation experiments confirmed that adsorbed polymer layer properties, through their effect on the dynamics of bubble-particle attachment, are critical to predicting the effectiveness of polymers used to prevent mineral recovery in flotation.
Odd-even effects on hydration of natural polyelectrolyte multilayers: An in situ synchrotron FTIR microspectroscopy study
Publisher: Elsevier BV
Date: 10-2019
DOI: 10.1016/J.JCIS.2019.06.036
Abstract: Odd-even effects in polysaccharide polyelectrolyte multilayers influence their hydration content and the chemical environment of the water within them. Polysaccharide polyelectrolyte multilayers (PEMs) composed of pharmaceutical grade fucoidan and chitosan were studied under confinement using synchrotron FTIR microspectroscopy at increasing pressure, in order to isolate and measure infrared spectra of water within the PEM, without interference from bulk water. Complementary studies of the PEMs were carried out using lab-based in situ attenuated total reflectance Fourier transform spectroscopy (ATR FTIR) and quartz crystal microbalance with dissipation monitoring (QCM-D), as well as zeta potential measurements, to determine the quantity of adsorbed polymer, hydration content, film thickness, viscoelastic properties and surface charge during layer-by-layer deposition. The hydration of the PEM followed a saw-tooth profile, known as the odd-even effect, where the film increased hydration with fucoidan adsorption and dehydrated/densified with chitosan adsorption. The water structure within the film showed a lower degree of hydrogen bonding than water in the bulk electrolyte. However, the water structure/environment was independent of the terminating layer of the PEM, in spite of the alteration in percentage hydration water, indicating only a partial proof of the initial hypothesis for this multilayer system (hydration amount changes, hydration water environment does not).
Dynamics of Capillary-Driven Flow in Open Microchannels
Publisher: American Chemical Society (ACS)
Date: 07-09-2011
DOI: 10.1021/JP2065826
Education plus exercise for persistent gluteal tendinopathy improves quality of life and is cost-effective compared with corticosteroid injection and wait and see: economic evaluation of a randomised
Publisher: Elsevier BV
Date: 2023
Influence of Aqueous Phase Composition on Double Emulsion Stability and Colour Retention of Encapsulated Anthocyanins
Publisher: MDPI AG
Date: 23-12-2021
Abstract: Water-in-oil-in-water (W1/O/W2) emulsions (double emulsions) have often been used for the encapsulation of bioactive compounds such as anthocyanins. Instability of both anthocyanins and double emulsions creates a need for a tailored composition of the aqueous phase. In this work, double emulsions with a gelled internal water phase were produced and monitored over a 20-day storage period. The effect of the electrolyte phase composition (varying electrolyte components, including adipic acid, citric acid, and varying concentration of potassium chloride (KCl)) on anthocyanin and double emulsion stability was analysed using colour analysis, droplet sizing, and emulsion rheology. The effect of electrolytes on colour retention was shown to differ between the primary W1/O emulsion and the secondary W1/O/W2 emulsion. Furthermore, droplet size analysis and emulsion rheology highlighted significant differences in the stability and structural behaviour of the emulsions as a function of electrolyte composition. In terms of colour retention and emulsion stability, a citrate-buffered system performed best. The results of this study highlight the importance of strict control of aqueous phase constituents to prevent anthocyanin degradation and maximise double emulsion stability. Additional experiments analysed the effect of pectin chemistry on the anthocyanin colour retention and leakage, finding no conclusive difference between the unmodified and amidated pectin.
Atomic force microscopy for determining surface interactions of relevance for food foams and emulsions
Publisher: Wiley
Date: 21-03-2014
Molecularly-Thin Precursor Films of Imidazolium-Based Ionic Liquids on Mica
Publisher: American Chemical Society (ACS)
Date: 31-10-2013
DOI: 10.1021/JP4062863
Influence of n-octanol and α-terpineol on thin film stability and bubble attachment to hydrophobic surface
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C2CP43545D
Abstract: We have investigated the influence of concentration of surfactants typically used as flotation frothers (α-terpineol and n-octanol) and roughness of the solid surface on phenomena occurring during rising bubble collisions with a model hydrophobic Teflon surface. The time of three-phase contact (TPC) formation (t(TPC)) and the time of drainage (t(D)) of the film formed between the colliding bubble and Teflon surfaces were determined using a high-speed camera working with a frequency 1040 Hz. The Teflon surface roughness was varied on a microscopic scale, within a roughness ranging between 1 and 100 μm. We have found that the roughness of the Teflon surface is a crucial factor of the kinetics of the TPC formation, both in the absence and in the presence of the surfactants. With the surface roughness increasing from ca. 1 to 80 μm the t(TPC) can be shortened by an order of magnitude, i.e. from 105 ms down to a few milliseconds. We have demonstrated that bouncing of the colliding bubble is responsible for the large differences in the times of TPC formation at the Teflon surfaces of different roughness. Low concentrations of α-terpineol and n-octanol caused a decrease in the t(TPC) with respect to distilled water. However, at high concentrations the t(TPC) was prolonged. The prolongation of the time of the TPC formation was dependent on the Teflon surface roughness and we have attributed this effect to different amounts of air present in the cavities and scratches of hydrophobic surfaces of different roughness. The mechanism of prolongation of the t(TPC) at high concentration of surface-active substances (frother overdosage) is proposed.
Adsorption of a Polyethoxylated Surfactant from Aqueous Solution to Silica Nanoparticle Films Studied with In Situ Attenuated Total Reflection Infrared Spectroscopy and Colloid Probe Atomic Force Microscopy.
Publisher: American Chemical Society (ACS)
Date: 20-10-2018
DOI: 10.1021/ACS.LANGMUIR.8B01351
Abstract: Polyethoxylated (PEO) surfactant adsorption to silica under aqueous conditions is an important physical process in a multitude of industries. Consequently, a considerable number of spectroscopic and other studies have been carried out to ascertain the molecular/structural details of the adsorbed surfactant and the kinetics of PEO surfactant adsorption. However, the use of infrared spectroscopy to probe surfactant adsorption at the silica/aqueous solution interface has been limited because of the instability of silica particle films under aqueous conditions and the opacity of silicon prisms below 1300 cm
ATR FTIR Study of the Interaction of TiO2 Nanoparticle Films with β-Lactoglobulin and Bile Salts
Publisher: American Chemical Society (ACS)
Date: 03-11-2021
DOI: 10.1021/ACS.LANGMUIR.1C01830
Abstract: The technique of in situ particle film attenuated total reflection Fourier transform infrared spectroscopy (ATR FTIR) has been used to probe the adsorption and coadsorption (sequential) of a common food protein (β-lactoglobulin, BLG) and two representative bile salts (taurocholic acid and glycocholic acid, abbreviated as TCA and GCA) onto the surface of titanium dioxide (TiO
Microstructure—Thermal Property Relationships of Poly (Ethylene Glycol-b-Caprolactone) Copolymers and Their Micelles
Publisher: MDPI AG
Date: 16-10-2022
Abstract: The crystallinity of polymers strongly affects their properties. For block copolymers, whereby two crystallisable blocks are covalently tethered to one another, the molecular weight of the in idual blocks and their relative weight fraction are important structural parameters that control their crystallisation. In the case of block copolymer micelles, these parameters can influence the crystallinity of the core, which has implications for drug encapsulation and release. Therefore, in this study, we aimed to determine how the microstructure of poly(ethylene glycol-b-caprolactone) (PEG-b-PCL) copolymers contributes to the crystallinity of their hydrophobic PCL micelle cores. Using a library of PEG-b-PCL copolymers with PEG number-average molecular weight (Mn) values of 2, 5, and 10 kDa and weight fractions of PCL (fPCL) ranging from 0.11 to 0.67, the thermal behaviour and morphology were studied in blends, bulk, and micelles using differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WXRD), and Synchrotron wide-angle X-ray scattering (WAXS). Compared to PEG and PCL homopolymers, the block copolymers displayed reduced crystallinity in the bulk phase and the in idual blocks had a large influence on the crystallisation of one another. The fPCL was determined to be the dominant contributor to the extent and order of crystallisation of the two blocks. When fPCL 0.35, the initial crystallisation of PEG led to an amorphous PCL phase. At fPCL values between 0.35 and 0.65, PEG crystallisation was followed by PCL crystallisation, whereas this behaviour was reversed when fPCL 0.65. For lyophilised PEG-b-PCL micelles, the crystallinity of the core increased with increasing fPCL, although the core was predominately amorphous for micelles with fPCL 0.35. These findings contribute to understanding the relationships between copolymer microstructure and micelle core crystallinity that are important for the design and performance of micellar drug delivery systems, and the broader application of polymer micelles.
Kinetics of bubble collision and attachment to hydrophobic solids: I. Effect of surface roughness
Publisher: Elsevier BV
Date: 2007
Electrostatic attraction between a hydrophilic solid and a bubble
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/C0CP01367F
Abstract: The contact between fine hydrophilic α-Al(2)O(3) particles and nitrogen bubbles was studied as a function of solution composition in single bubble capture experiments, where the bubble collection efficiency was measured. The surface charges of both bubble and particle were controlled by varying the electrolyte concentration and pH of the solution. In all experiments the bubbles were negatively charged while the α-Al(2)O(3) particles were either negatively (above pH of the isoelectric point, pH(IEP)) or positively (below pH(IEP)) charged. The collection efficiency was found to be strongly influenced by the surface charge of the particles. The maximum collection efficiency occurred when the bubble and particle were oppositely charged (at low pH values) and at low salt concentration, i.e. when a long range attractive electrostatic interaction is present. In the case where both bubble and particle were of the same charge, the collection efficiency was near to zero within experimental error and was not influenced by either salt concentration or pH. This is the first experimental proof of the concept of 'contactless flotation', first proposed by Derjaguin and Dukhin in 1960, with far reaching implications from minerals processing to biology.
Fractionation and characterisation of hard milk fat crystals using atomic force microscopy
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'
Recent advances in studies of bubble-solid interactions and wetting film stability
Publisher: Elsevier BV
Date: 12-2019
Haptotatic Plasma Polymerized Surfaces for Rapid Tissue Regeneration and Wound Healing
Publisher: American Chemical Society (ACS)
Date: 22-11-2016
Abstract: Skin has a remarkable capacity for regeneration however, with an ever aging population, there is a growing burden to the healthcare system from chronic wounds. Novel therapies are required to address the problems associated with nonhealing chronic wounds. Novel wound dressings that can encourage increased reepithelialization could help to reduce the burden of chronic wounds. A suite of chemically defined surfaces have been produced using plasma polymerization, and the ability of these surfaces to support the growth of primary human skin cells has been assessed. Additionally, the ability of these surfaces to modulate cell migration and morphology has also been investigated. Keratinocytes and endothelial cells were extremely sensitive to surface chemistry showing increased viability and migration with an increased number of carboxylic acid functional groups. Fibroblasts proved to be more tolerant to changes in surface chemistry however, these cells migrated fastest over amine-functionalized surfaces. The novel combination of comprehensive chemical characterization coupled with the focus on cell migration provides a unique insight into how a material's physicochemical properties affect cell migration.
Cascade partial coalescence phenomena at electrolyte–oil interfaces and determination of bounds for the surface potential
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3SM27772K
Internet-Delivered Exercise and Pain-Coping Skills Training for Chronic Knee Pain
Publisher: American College of Physicians
Date: 21-02-2017
DOI: 10.7326/P17-9031
Dynamic wetting of imidazolium-based ionic liquids on gold and glass
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7CP06404G
Abstract: Experimental data and theoretical fitting for ionic liquid wetting on application-relevant substrates.
Clustering of the Mechanosensitive Ion Channels of Large and Small Conductance MscL and MscS - a FRET-Flim Study
Publisher: Elsevier BV
Date: 2012
Organic energy devices from ionic liquids and conducting polymers
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5TC03281D
Abstract: The interaction of ionic liquids and conducting polymers were studied, and organic electronic devices fabricated using this new insight.
Cross-cultural Adaptation and Validation of the Nepali Translation of the Patient-Specific Functional Scale
Publisher: Journal of Orthopaedic & Sports Physical Therapy (JOSPT)
Date: 08-2018
Abstract: Background The Patient-Specific Functional Scale (PSFS) is among the most commonly used measures to assess physical function. Objectives We aimed to translate and cross-culturally validate the PSFS to Nepali and further assess its psychometric properties. Methods This longitudinal, single-arm cohort study translated and cross-culturally adapted the PSFS to Nepali (PSFS-NP) following recommended guidelines. A s le of 104 Nepalese with musculoskeletal pain was recruited to evaluate the psychometric properties of the PSFS-NP. We assessed the internal consistency (Cronbach alpha), 2-week test-retest reliability (intraclass correlation coefficient [ICC
Hydrodynamics in nanoscale confinement: SFA and colloid probe AFM liquid drainage experiments
Publisher: IOP Publishing
Date: 11-12-2012
Subgrouping and TargetEd Exercise pRogrammes for knee and hip OsteoArthritis (STEER OA): a systematic review update and individual participant data meta-analysis protocol
Publisher: BMJ
Date: 12-2017
DOI: 10.1136/BMJOPEN-2017-018971
Abstract: Knee and hip osteoarthritis (OA) is a leading cause of disability worldwide. Therapeutic exercise is a recommended core treatment for people with knee and hip OA, however, the observed effect sizes for reducing pain and improving physical function are small to moderate. This may be due to insufficient targeting of exercise to subgroups of people who are most likely to respond and/or suboptimal content of exercise programmes. This study aims to identify: (1) subgroups of people with knee and hip OA that do/do not respond to therapeutic exercise and to different types of exercise and (2) mediators of the effect of therapeutic exercise for reducing pain and improving physical function. This will enable optimal targeting and refining the content of future exercise interventions. Systematic review and in idual participant data meta-analyses. A previous comprehensive systematic review will be updated to identify randomised controlled trials that compare the effects of therapeutic exercise for people with knee and hip OA on pain and physical function to a non-exercise control. Lead authors of eligible trials will be invited to share in idual participant data. Trial-level and participant-level characteristics (for baseline variables and outcomes) of included studies will be summarised. Meta-analyses will use a two-stage approach, where effect estimates are obtained for each trial and then synthesised using a random effects model (to account for heterogeneity). All analyses will be on an intention-to-treat principle and all summary meta-analysis estimates will be reported as standardised mean differences with 95% CI. Research ethical or governance approval is exempt as no new data are being collected and no identifiable participant information will be shared. Findings will be disseminated via national and international conferences, publication in peer-reviewed journals and summaries posted on websites accessed by the public and clinicians. CRD 42017054049.
Inducement of dynamic adsorption structures at liquid/gas interface: acceleration and velocity of the detaching bubble
Publisher: Unpublished
Date: 2005
Measurement properties of the Nepali version of the Connor Davidson resilience scales in individuals with chronic pain
Publisher: Springer Science and Business Media LLC
Date: 03-04-2018
Influence of surface active substances on bubble motion and collision with various interfaces
Publisher: Elsevier BV
Date: 06-2005
DOI: 10.1016/J.CIS.2004.08.004
Abstract: Bubble motion as a function of distance from a point of its detachment and phenomena occurring during the bubble approach and collision with liquid/gas and liquid/solid interfaces in pure water and solutions of various surface active substances are described and discussed. It is showed that presence of surface active substance has a profound influence on values of the terminal velocity and profiles of the local velocity. At low solutions concentrations there are three distinct stages in the bubble motion: (i) a rapid acceleration, (ii) a maximum velocity value followed by its monotonic decrease, and (iii) attainment of the terminal velocity, while at high concentrations (and in pure water) there are only stages (i) and (iii). It is showed that the bubble terminal velocity decreases rapidly at low surfactant concentration, but there can be found some characteristic concentrations (adsorption coverage's) above which the velocity almost stopped to decrease. Immobilization of the bubble surface resulting from adsorption of the surface active substances (surface tension gradients inducement) causes over twofold lowering of the bubble velocity. Presence of the maximum on the local velocity profiles is an indication that a stationary non-uniform distribution of adsorption coverage (needed for immobilization the bubble interface) was not established there. When the rising bubble arrives at liquid/gas interface or liquid/solid interface there can be formed either foam or wetting film or three-phase contact (TPC). It is showed that prior to the foam and/or wetting film formation the bubble colliding with the interfaces can bounce backward and simultaneously its shape pulsates rapidly with a frequency over 1000 Hz. It is rather unexpected that even in the case of the free surface the bubble's shape and consequently its surface area can vary so rapidly. It shows straightforward that on such a rapidly distorted interface the adsorption coverage can be very different from that at equilibrium. This fact should be taken into account more appropriately in the discussion of the mechanism of formation and stabilization of various dispersed systems (e.g. foams, emulsions). Bubble collision with solids and formation of the three-phase contact is a necessary condition for flotation separation. It is rather common understanding that immediate attachment should occur in the case of hydrophobic surface, while there should be no attachment in the case of the hydrophilic ones. It is reported that even in the case of such hydrophobic solid surface as Teflon, the bubble attachment did not need to occur at first collision and in distilled water the bubble can bounce a few times without attachment. Presence of frother facilitates the bubble attachment to hydrophobic solid surface. Time scale of the TPC formation is very short, of an order of single ms. It was observed that presence of a micro-bubble at the solid surface facilitated drastically an attachment of the colliding bubble. Roughness of Teflon surface increases probability of the bubble attachment-most probably-as a result of higher probability of micro- and/or nano-bubbles presence at the solid surface.
ATR FTIR spectroscopy of protein and surfactant adsorption to the oil-water interface
Publisher: Elsevier BV
Date: 11-2023
The effect of emulsifier type on the secondary crystallisation of monoacylglycerol and triacylglycerols in model dairy emulsions
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.
Why clinicians should consider the role of culture in chronic pain
Publisher: Elsevier BV
Date: 09-2018
A europium metal–organic framework for dual Fe3+ ion and pH sensing
Publisher: Springer Science and Business Media LLC
Date: 14-07-2022
DOI: 10.1038/S41598-022-15663-Z
Abstract: Metal–organic frameworks (MOFs) with ratiometric sensing properties are desirable for many applications due to their intrinsic self-calibration. We report the re-assessment of the sensing properties of a MOF, originally reported as containing europium(III) and 2-hydroxyterephtalic acid, and having fluorescent ratiometric iron(III) sensing properties. Synchrotron single-crystal X-ray diffraction and proton nuclear magnetic resonance ( 1 H NMR) spectroscopy revealed that the MOF is composed of 2-methoxyterephthalate, not 2-hydroxyterephthalate as originally reported. We found that the MOF exhibits a sensor turn-off response towards Fe 3+ ion concentrations in the range 0.5–3.7 ppm (band 425 nm), and a turn-on response towards a decrease of pH from 5.4 to 3.0 (band 375 nm), both resulting from the addition of acidic Fe 3+ salt solution to a MOF suspension. Thus, the ratiometric sensing properties and the originally proposed mechanism no longer apply our work reveals a dynamic quenching mechanism for the fluorescence turn-off response due to the presence of Fe 3+ ions, and a ligand protonation mechanism for the turn-on response to a decrease in pH. Our work highlights the importance of a thorough investigation of the structure of any newly synthesized MOF, and, in the case of potential sensors, their selectivity and any environmental effects on their sensing behavior.
Interfacial characterisation for flotation: 1. Solid-liquid interface
Publisher: Elsevier BV
Date: 09-2018
Ultrathin Wetting Films on Hydrophilic Titania Surfaces: Equilibrium and Dynamic Behavior
Publisher: American Chemical Society (ACS)
Date: 17-05-2011
DOI: 10.1021/JP200387W
Diffusing wave spectroscopy (DWS) methods applied to double emulsions
Publisher: Elsevier BV
Date: 09-2018
Polyelectrolyte multilayer formation on protein layer supports
Publisher: Elsevier BV
Date: 11-2021
S-Nitrosothiol Plasma-Modified Surfaces for the Prevention of Bacterial Biofilm Formation
Publisher: American Chemical Society (ACS)
Date: 25-09-2019
Combination of Principal Component Analysis and Genetic Algorithm for Microbial Biomarker Identification in Obesity
Publisher: IEEE
Date: 12-2018
Injectable Diels-Alder cycloaddition hydrogels with tuneable gelation, stiffness and degradation for the sustained release of T-lymphocytes
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2TB00274D
Abstract: Highly efficient, selective and cytocompatible fulvene–maleimide cycloaddition chemistry was applied for the preparation of injectable, cell encapsulating/releasing hydrogels with tuneable gelation and degradation kinetics.
The influence of polyanion molecular weight on polyelectrolyte multilayers at surfaces: protein adsorption and protein–polysaccharide complexation/stripping on natural polysaccharide films on solid su
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7CP02599H
Abstract: Two different fucoidan polymers have been used to create substrates for protein adsorption studies.
Influence of Polyelectrolyte Layers Deposited on Mica Surface on Wetting Film Stability and Bubble Attachment
Publisher: American Chemical Society (ACS)
Date: 27-03-2007
DOI: 10.1021/JP068486E
Revealing the Nanostructure of Glyceryl Tristearate Crystals by Atomic Force Microscopy
Publisher: American Chemical Society (ACS)
Date: 30-11-2018
Dynamics of capillary-driven liquid-liquid displacement in open microchannels
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4CP03910F
Abstract: For capillary-driven liquid–liquid displacement in rectangular open microchannels, the square of the position of the liquid–liquid front increases linearly with time, whereas the flow velocity decreases with increasing channel width.
Pain education for patients with non-specific low back pain in Nepal: protocol of a feasibility randomised clinical trial (PEN-LBP Trial)
Publisher: BMJ
Date: 08-2018
DOI: 10.1136/BMJOPEN-2018-022423
Abstract: Low back pain (LBP) is the leading cause of years lived with disability in Nepal and elsewhere. Management of LBP that is evidence-based, easily accessible, cost-effective and culturally appropriate is desirable. The primary aim of this feasibility study is to determine if it is feasible to conduct a full randomised clinical trial evaluating the effectiveness of pain education as an intervention for in iduals with LBP in Nepal, relative to guideline-based physiotherapy treatment. The findings of the study will inform the planning of a full clinical trial and if any modifications are required to the protocol before undertaking a full trial. This protocol describes an assessor-blinded feasibility clinical trial investigating feasibility of the pain education intervention in patients with non-specific LBP in a physiotherapy hospital in Kathmandu, Nepal. Forty patients with LBP will be randomly allocated to either pain education or guideline-based physiotherapy treatment (control). Outcomes will be assessed at baseline and at a 1 week post-treatment. The primary outcomes are related to feasibility, including: (1) participant willingness to participate in a randomised clinical trial, (2) feasibility of assessor blinding, (3) eligibility and recruitment rates, (4) acceptability of screening procedures and random allocation, (5) possible contamination between the groups, (6) intervention credibility, (7) intervention adherence, (8) treatment satisfaction and (9) difficulty in understanding the interventions being provided. The protocol was approved by Nepal Health Research Council (NHRC registration number: 422/2017) and University of Otago Human Ethics Committee for Health (registration number: H17/157). The results of the study will be presented at national and international conferences and published in a peer-reviewed journal. NCT03387228 Pre-results.
Nanoscale iodophoric poly(vinyl amide) coatings for the complexation and release of iodine for antimicrobial surfaces
Publisher: Elsevier BV
Date: 12-2023
Isoelectric state and stability of foam films, bubbles and foams from PEO–PPO–PEO triblock copolymer (P85)
Publisher: Springer Science and Business Media LLC
Date: 07-12-2005
Bubble motion as a method of detection of organic contaminations in water
Publisher: Unpublished
Date: 2005
Antibiofilm Nitric Oxide-Releasing Polydopamine Coatings
Publisher: American Chemical Society (ACS)
Date: 28-01-2019
Abstract: The growing number of patient morbidity related to nosocomial infections has placed an importance on the development of new antibacterial coatings for medical devices. Here, we utilize the versatile adhesion property of polydopamine (pDA) to design an antibacterial coating that possesses low-fouling and nitric oxide (NO)-releasing capabilities. To demonstrate this, glass substrates were functionalized with pDA via immersion in alkaline aqueous solution containing dopamine, followed by grafting of low-fouling polymer (poly(ethylene glycol) (PEG)) via Michael addition and subsequent formation of N-diazeniumdiolate functionalities (NO precursors) by purging with NO gas. X-ray photoelectron spectroscopy confirmed the successful grafting of PEG and formation of N-diazeniumdiolate on polydopamine-coated substrates. NO release from the coating was observed over 2 days, and NO loading is tunable by the pDA film thickness. The antibacterial efficiency of the coatings was assessed using Gram-negative Pseudomonas aeruginosa (i.e., wild-type PAO1 and multidrug-resistant PA37) and Gram-positive Staphylococcus aureus (ATCC 29213). The NO-releasing PEGylated pDA film inhibited biofilm attachment by 96 and 70% after exposure to bacterial culture solution for 24 and 36 h, respectively. In contrast, films that do not contain NO failed to prevent biofilm formation on the surfaces at these time points. Furthermore, this coating also showed 99.9, 97, and 99% killing efficiencies against surface-attached PAO1, PA37, and S. aureus bacteria. Overall, the combination of low-fouling PEG and antibacterial activity of NO in pDA films makes this coating a potential therapeutic option to inhibit biofilm formation on medical devices.
A real time biofeedback using Kinect and Wii to improve gait for post-total knee replacement rehabilitation: a case study report
Publisher: Informa UK Limited
Date: 04-09-2015
DOI: 10.3109/17483107.2015.1080767
Abstract: This study aimed to develop a low-cost real-time biofeedback system to assist with rehabilitation for patients following total knee replacement (TKR) and to assess its feasibility of use in a post-TKR patient case study design with a comparison group. The biofeedback system consisted of Microsoft Kinect(TM) and Nintendo Wii balance board with a dedicated software. A six-week inpatient rehabilitation program was augmented by biofeedback and tested in a single patient following TKR. Three patients underwent a six weeks standard rehabilitation with no biofeedback and served as a control group. Gait, function and pain were assessed and compared before and after the rehabilitation. The biofeedback software incorporated real time visual feedback to correct limb alignment, movement pattern and weight distribution. Improvements in pain, function and quality of life were observed in both groups. The strong improvement in the knee moment pattern demonstrated in the case study indicates feasibility of the biofeedback-augmented intervention. This novel biofeedback software has used simple commercially accessible equipment that can be feasibly incorporated to augment a post-TKR rehabilitation program. Our preliminary results indicate the potential of this biofeedback-assisted rehabilitation to improve knee function during gait. Research is required to test this hypothesis. Implications for Rehabilitation The real-time biofeedback system developed integrated custom-made software and simple low-cost commercially accessible equipment such as Kinect and Wii board to provide augmented information during rehabilitation following TKR. The software incorporated key rehabilitation principles and visual feedback to correct alignment of the lower legs, pelvic and trunk as well as providing feedback on limbs weight distribution. The case study patient demonstrated greater improvement in their knee function where a more normal biphasic knee moment was achieved following the six-week biofeedback intervention.
Nature of arsenic sites in arsenian pyrite - A synchrotron radiation X-ray photoelectron spectroscopy (SRXPS) study
Publisher: Elsevier BV
Date: 08-2022
Influence of n-hexanol and n-octanol on wetting properties and air entrapment at superhydrophobic surfaces
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C0CP01940B
Abstract: Superhydrophobic surfaces have recently attracted a lot of attention due to their self-cleaning properties. The superhydrophobic surfaces used in our studies were prepared using a mixed inorganic-organic coating. In order to check how short chain surface active agents affect the surface energy of such surfaces, their wettability (sessile drop technique) and the kinetics of the three phase contact formation were studied. It was found that with increasing concentrations of n-hexanol and n-octanol the surface energy of these surfaces was only slightly changed, i.e. a small decrease in contact angle values with increasing solution concentration was detected. Even for the most concentrated n-hexanol and n-octanol solutions, the contact angles were in the range 145-155° and the drop rolled off, indicating that the studied surfaces stayed superhydrophobic. Air bubbles, upon collision with such superhydrophobic surfaces, spread over the superhydrophobic surface within milliseconds in the studied solutions.
Interaction force between an air bubble and a hydrophilic spherical particle in water, measured by the colloid probe technique
Publisher: Elsevier BV
Date: 08-2009
Adsorption of Carboxymethyl Cellulose onto Titania Particle Films Studied with in Situ IR Spectroscopic Analysis.
Publisher: American Chemical Society (ACS)
Date: 30-07-2019
DOI: 10.1021/ACS.LANGMUIR.9B01011
Abstract: Adsorption of carboxymethyl cellulose (CMC) in aqueous solution onto a titania nanoparticle film has been studied using in situ attenuated total reflectance infrared spectroscopy (ATR-IR). CMC was adsorbed onto the positively charged titania surface in neutral, partially charged, and fully charged state. The response of the adsorbed polyelectrolyte layer was monitored upon changing the electrolyte pH and ionic strength. The degree of dissociation of the CMC increased upon adsorption onto the titania surface and changed with the surface coverage. Ionic strength change was observed to influence the degree of dissociation of the adsorbed CMC similar as when in solution. No significant peak shifts were observed in the spectrum of the adsorbed CMC during adsorption or in response to changing solution conditions therefore, inner-sphere complexation between the carboxyl groups and the titania could not be confirmed. The effect of ion identity on the adsorption process was studied using soft and hard cations and mono- and alent cations. The presence of a alent counterion was observed to cause changes in the carboxymethyl vibrations, which can be related to formation of intra- or interchain linkages.
Incorporation and antimicrobial activity of nisin Z within carrageenan/chitosan multilayers
Publisher: Springer Science and Business Media LLC
Date: 18-01-2021
DOI: 10.1038/S41598-020-79702-3
Abstract: An antimicrobial peptide, nisin Z, was embedded within polyelectrolyte multilayers (PEMs) composed of natural polysaccharides in order to explore the potential of forming a multilayer with antimicrobial properties. Using attenuated total reflection Fourier transform infrared spectroscopy (ATR FTIR), the formation of carrageenan/chitosan multilayers and the inclusion of nisin Z in two different configurations was investigated. Approximately 0.89 µg cm −2 nisin Z was contained within a 4.5 bilayer film. The antimicrobial properties of these films were also investigated. The peptide containing films were able to kill over 90% and 99% of planktonic and biofilm cells, respectively, against Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) strains compared to control films. Additionally, surface topography and wettability studies using atomic force microscopy (AFM) and the captive bubble technique revealed that surface roughness and hydrophobicity was similar for both nisin containing multilayers. This suggests that the antimicrobial efficacy of the peptide is unaffected by its location within the multilayer. Overall, these results demonstrate the potential to embed and protect natural antimicrobials within a multilayer to create functionalised coatings that may be desired by industry, such as in the food, biomaterials, and pharmaceutical industry sectors.
Probing of polyelectrolyte monolayers by zeta potential and wettability measurements
Publisher: Elsevier BV
Date: 10-2008
DOI: 10.1016/J.JCIS.2008.06.053
Abstract: Detection of the very first step of polyelectrolyte adsorption onto a solid support is of great importance for understanding mechanisms of solid surface modification. It was shown that streaming potential and contact angle measurements can be successfully used for polyelectrolyte (PE) adsorption characterization in a broad range of surface coverage. Cationic polyallylamine hydrochloride (PAH) was used for the formation of the layer. The electrokinetic characteristics of the substrate covered by the PAH layer were compared with contact angles measured under wet (captive air bubble/substrate in water) and dry (sessile water droplet/dried substrate) conditions. It has been demonstrated that contact angle values determined under both conditions are in good agreement. The observed rapid increase in the contact angle from zero for the bare mica surface to the value close to one characteristic of the PAH monolayer appears in the same PAH coverage range as zeta potential value changes due to adsorption. These results show that wettability can be as sensitive to the presence of small amounts of adsorbed species as electrokinetic measurements.
Wetting films in attachment of the colliding bubble
Publisher: Elsevier BV
Date: 10-2007
DOI: 10.1016/J.CIS.2007.04.010
Abstract: The importance of wetting films in three phase contact formation and attachment of the bubble colliding with different solid surfaces is described The paper reviews main factors determining stability, drainage, rupture, three phase contact (TPC) formation and expansion of the TPC perimeter under dynamic conditions. There are shortly reviewed specific forces of interactions (DLVO and non-DLVO), kinetics of drainage and mechanisms of the wetting film rupture, as well as the TPC formation and expansion. The review is focused on the role of hydrophobic/hydrophilic properties, surface roughness and heterogeneity of the solid substrates for the wetting film stability and rupture under dynamic conditions. Phenomena occurring during collisions of the rising bubble with solid plates of different surface properties are discussed in relation to the kinetics of the wetting films drainage and TPC formation. It is showed that stability and drainage kinetics of the wetting films are decisive for the TPC formation and attachment of the colliding bubble.
Long-term adherence of human brain cells in vitro is enhanced by charged amine-based plasma polymer coatings
Publisher: Elsevier BV
Date: 03-2022
The influence of pH on the interfacial behaviour of Quillaja bark saponin at the air-solution interface
Publisher: Elsevier BV
Date: 04-2019
DOI: 10.1016/J.COLSURFB.2019.01.017
Abstract: The interfacial behavior of surfactants present in a natural extract from Quillaja saponaria Molina bark at the air-solution interface is studied by measurements of interfacial tension, interfacial elasticity, and interfacial reflectance FTIR spectroscopy. The active molecule, saponin, is observed directly at the air-solution interface (via reflectance FTIR spectroscopy) above and below the pKa of the molecule, and spectra confirm the altered charge of the interfacial layer at the two solution conditions. For all concentrations of saponin studied, and at pH values below and above pKa (i.e. pH 3 and 7), a reduction in interfacial tension as a function of time is observed, with some differences in early time-scale adsorption and with lower values of quasi-equilibrium interfacial tension for pH 3. The interfacial layer is seen to be elastic, as determined from measurements of hydrostatic expansion, with some variation at the two pH values, and as a function of concentration. In addition to interfacial layer characterisation, the interaction between two air-solution interfaces is probed using bubble collisions with an air-solution interface. This experiment allows for observation of thin film drainage kinetics and determination of the final foam film thickness for the case when one of the interfaces is at equilibrium while the dynamic adsorption layer is being established at the other. This is the first time when the interactions between such interfaces (i.e. only one being at equilibrium) have been studied. This is of particular importance for the formation stage of foams, during which time many of the interfaces are not at equilibrium. When two interfaces interact across a thin liquid film, pH is seen to significantly influence foam film thickness.
Air at hydrophobic surfaces and kinetics of three phase contact formation
Publisher: Elsevier BV
Date: 03-2009
DOI: 10.1016/J.CIS.2008.10.003
Abstract: This review focuses on the importance of air presence at hydrophobic solid surfaces for wetting film rupture and kinetics of three phase contact formation. Affinity to air is a typical feature of hydrophobic surfaces, but it has been often either overlooked or not taken into consideration. When the hydrophobic surface, contacted earlier with air, is immersed into water then air can stay attached to the surface. The origin of long range hydrophobic forces and data showing that these interactions were due to the bridging of nanobubbles attached to the hydrophobic surfaces are discussed. A major part of the review is devoted to the description and analysis of data showing that air (nano-, micro-bubbles and/or air film) present at a hydrophobic surface facilitated rupture of the liquid film and three phase contact formation during bubble collisions with flat Teflon plates of different surface roughness. Although all Teflon plates were highly hydrophobic (contact angles ca. 100 degrees -130 degrees ) the time of the three phase contact (TPC) formation and attachment of the colliding bubble was strongly affected by the plate surface roughness. The time of the TPC formation was shortened from over 80 down to 2-3 ms when the roughness was increased from below 1 microm to over 50 microm. Higher surface roughness means that larger amounts of air was entrapped during the Teflon plates' immersion in water. Additional experimental evidence is given, showing that facilitation of the TPC formation and the bubble attachment was due to air presence and re-distribution over the Teflon surfaces: i) prolonging the plate immersion time resulted in quicker attachment ii) irregular and disappearing air pockets were recorded at a Teflon surface iii) a satellite bubble left at a Teflon surface during the first collision facilitated the attachment iv) attachment always occurred during the first collision in the case of a very rough "Teflon V" surface, but in highly concentrated n-octanol and n-heptanol solutions there was bouncing and attachment occurred during the second collision, moreover v) the degree of bubble kinetic energy transferred into surface energy was significantly smaller during collisions with hydrophobic (Teflon) surfaces than with the hydrophilic ones. The mechanism of air entrapment and redistribution over Teflon plates immersed in water is presented.
Interfacial Tension Sensor for Low Dosage Surfactant Detection
Publisher: MDPI AG
Date: 03-02-2021
Abstract: Currently there are no available methods for in-line measurement of gas-liquid interfacial tension during the flotation process. Microfluidic devices have the potential to be deployed in such settings to allow for a rapid in-line determination of the interfacial tension, and hence provide information on frother concentration. This paper presents the development of a simple method for interfacial tension determination based on a microfluidic device with a flow-focusing geometry. The bubble generation frequency in such a microfluidic device is correlated with the concentration of two flotation frothers (characterized by very different adsorption kinetic behavior). The results are compared with the equilibrium interfacial tension values determined using classical profile analysis tensiometry.
Economic evaluation: a reader’s guide to studies of cost-effectiveness
Publisher: Springer Science and Business Media LLC
Date: 15-12-2022
DOI: 10.1186/S40945-022-00154-1
Abstract: Understanding what an economic evaluation is, how to interpret it, and what it means for making choices in a health delivery context is necessary to contribute to decisions about healthcare resource allocation. The aim of this paper to demystify the working parts of a health economic evaluation, and explain to clinicians and clinical researchers how to read and interpret cost-effectiveness research. This primer distils key content and constructs of economic evaluation studies, and explains health economic evaluation in plain language. We use the PICOT (participant, intervention, comparison, outcome, timeframe) clinical trial framework familiar to clinicians, clinical decision-makers, and clinical researchers, who may be unfamiliar with economics, as an aide to reading and interpreting cost-effectiveness research. We provide ex les, primarily of physiotherapy interventions for osteoarthritis. Economic evaluation studies are essential to improve decisions about allocating resources, whether those resources be your time, the capacity of your service, or the available funding across the entire healthcare system. The PICOT framework can be used to understand and interpret cost-effectiveness research.
Mechanical properties of thin films at the dodecane-water interface, for multilayered emulsion applications
Publisher: Elsevier BV
Date: 10-2021
The influence of polyanion molecular weight on polyelectrolyte multilayers at surfaces: elasticity and susceptibility to saloplasticity of strongly dissociated synthetic polymers at fluid–fluid interf
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7CP02614E
Abstract: Decreasing polyanion chain length increases the elastic modulus and saloplasticity threshold in freestanding polyelectrolyte multilayers.
M INFLUENCE OF N-PENTANOL CONCENTRATION ON THE BUBBLE PULSATION AND BOUNCING
Publisher: Unpublished
Date: 2003
Isolating the interface of an emulsion using X-ray scattering and tensiometry to understand protein-modulated alkylglyceride crystallisation
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.
Influence of dissolved air on bubble attachment to highly oriented pyrolytic graphite
Publisher: Faculty of Geoengineering, Mining and Geology, Wrocław University of Technology, Wrocław
Date: 2018
DOI: 10.5277/PPMP1838
A Novel Soft Contact Piezo-Controlled Liquid Cell for Probing Polymer Films under Confinement using Synchrotron FTIR Microspectroscopy
Publisher: Springer Science and Business Media LLC
Date: 13-12-2018
DOI: 10.1038/S41598-018-34673-4
Abstract: Soft polymer films, such as polyelectrolyte multilayers (PEMs), are useful coatings in materials science. The properties of PEMs often rely on the degree of hydration, and therefore the study of these films in a hydrated state is critical to allow links to be drawn between their characteristics and performance in a particular application. In this work, we detail the development of a novel soft contact cell for studying hydrated PEMs (poly(sodium 4-styrenesulfonate) oly(allylamine hydrochloride)) using FTIR microspectroscopy. FTIR spectroscopy can interrogate the nature of the polymer film and the hydration water contained therein. In addition to reporting spectra obtained for hydrated films confined at the solid-solid interface, we also report traditional ATR FTIR spectra of the multilayer. The spectra (microspectroscopy and ATR FTIR) reveal that the PEM film build-up proceeds as expected based on the layer-by-layer assembly methodology, with increasing signals from the polymer FTIR peaks with increasing bilayer number. In addition, the spectra obtained using the soft contact cell indicate that the PEM film hydration water has an environment/degree of hydrogen bonding that is affected by the chemistry of the multilayer polymers, based on differences in the spectra obtained for the hydration water within the film compared to that of bulk electrolyte.
Influence of Bubble Kinetic Energy on its Bouncing During Collisions with Various Interfaces
Publisher: Wiley
Date: 19-05-2008
Adhesion between silica particles in an alcohol medium
Publisher: Informa UK Limited
Date: 2003
Effectiveness of an internet-delivered exercise and pain-coping skills training intervention for persons with chronic knee pain: A randomized trial
Publisher: American College of Physicians
Date: 21-02-2017
DOI: 10.7326/M16-1714
Arsenic clustering in arsenian pyrite: a combined photoemission and theoretical modeling study
Publisher: Mineralogical Society of America
Date: 05-2023
DOI: 10.2138/AM-2022-8415
Abstract: Arsenian pyrite is known to have a strong association with gold in most auriferous refractory deposits, and thus understanding the chemical speciation of arsenic in localized environments in arsenian pyrite provides an important basis for determining its reactivity and mobility. However, arsenic is fast-oxidizing among elements in the Fe-As-S system and hence it may exist in various chemical states, which renders it difficult to establish arsenic nature under pristine conditions, particularly in arsenian pyrite. Herein, arsenian pyrite s les were analyzed on a synchrotron soft X-ray spectroscopy beamline under ultrahigh vacuum conditions, and As-3d as well as S-2p spectra were collected. A comparison between the spectrum of bulk As-3d in the s les with its bulk counterpart in arsenopyrite revealed a 0.6 eV shift toward lower binding energies. This observation was similar to loellingite (FeAs2), where the binding energy shift was attributed to high electron density on As of the As-As dimer. Formation of As clusters resulting in comparable binding energy shifts was also proposed from the spectroscopic studies. The experiments were complemented by a series of first-principles calculations simulating four experimentally observed pyrite surfaces where surficial S atoms were randomly substituted by As. As such, six arsenian pyrite crystal surfaces were modeled, two of which constituted surficial As clusters replacing both S and Fe atoms. The surfaces were geometrically optimized, and surface energies were calculated along with the corresponding electronic structure providing a detailed distribution of partial charges for surficial atoms obtained from Löwdin population analysis. The calculated partial charges of atoms located at the surface arsenian pyrite indicated that while the electron density on the As atom of As-S dimers in arsenian pyrite is less negative than the As in bulk arsenopyrite, it is more negative for the As atom of As-As dimers, which were only seen in the surficial As clusters. This validated the description of As presence in arsenian pyrite as local clusters inducing localized lattice strain due to increased bond distances. Our findings offer a good background for future studies into the reactive sites in arsenian pyrite and how that compares with associated minerals, arsenopyrite, and pyrite.
Exercise and load modification versus corticosteroid injection versus ‘wait and see’ for persistent gluteus medius/minimus tendinopathy (the LEAP trial): a protocol for a randomised clinical trial
Publisher: Springer Science and Business Media LLC
Date: 30-04-2016
Can small air bubbles probe very low frother concentration faster?
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1SM01318A
Abstract: The differences in the degree of tangential immobilisation of small bubbles caused by two different frothers are discussed in the context of differences in the structure of the dynamic adsorption layer, which is formed during the bubble rise.
Mobile or Immobile? Rise Velocity of Air Bubbles in High-Purity Water
Publisher: American Chemical Society (ACS)
Date: 23-05-2019
The unusual surface chemistry of α-Al2O3 (0001)
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/C001222J
Abstract: We report on the influence of heat treatment on the surface chemistry of an α-alumina crystal. We compare its electrical double layer behaviour with that of 150 nm diameter α-Al(2)O(3) particles. Surface spectroscopy and zeta potential studies are used to understand the changes in surface chemistry. The pH(pzc) of an α-Al(2)O(3) (0001) single crystal (∼4) is more acidic than that of α-Al(2)O(3) particles (8.5), a difference explained by the dominance of [triple bond, length as m-dash]Al(2)OH surface groups on the single crystals and their charging behaviour. Heat treatment of the alumina surface causes a substantial decrease in the number of surface OH groups. Heating at 500 °C decreases the surface density of hydroxyl groups. Heating at 1050 °C also affects surface morphology and surface chemistry. The increased magnitude of the zeta potential and the pH(pzc) shift to lower pH suggest a surface reconstruction and the appearance of more acidic aluminium sites.
Interrogating the relationship between the microstructure of amphiphilic poly(ethylene glycol-b-caprolactone) copolymers and their colloidal assemblies using non-interfering techniques
Publisher: Elsevier BV
Date: 2022
Tuning polyelectrolyte multilayer structure by exploiting natural variation in fucoidan chemistry
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4SM02552K
Abstract: Polyelectrolyte multilayers of fucoidan with chitosan have film characteristics that depend on the species of seaweed from which the fucoidan is extracted. Acetylation of the fucoidan (and altered molecular weight) is implicated in the formation of denser, less hydrated multilayers.
Influence of adsorbed gas at liquid/solid interfaces on heterogeneous cavitation
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C2SC21321D
Translation, cross-cultural adaptation and psychometric properties of the Nepali versions of numerical pain rating scale and global rating of change
Publisher: Springer Science and Business Media LLC
Date: 12-2017
Nano-mechanical analyses of native and cross-linked collagen I matrices reveal the mechanical complexity of homogenous samples
Publisher: Frontiers Media SA
Date: 29-06-2022
Abstract: While it is now well appreciated that the extracellular matrix (ECM) exerts biomechanical cues that direct critical cellular behavior, including cell proliferation, differentiation, migration, and survival, the molecular mechanisms underlying these cues remain mysterious. It has long been known that the ECM is also a source of biochemical cues that influence these processes, but the way these interact with ECM biomechanics also remains largely unknown. The systematic study of these relationships has been h ered by a paucity of models and the tools to interrogate them. Studies of complex models and tissue s les employing techniques such as atomic force microscopy (AFM) have informed much of our current understanding of how mechanical cues are transduced by the ECM and how cells respond to them. However, key observations made using such complex systems cannot be reliably assigned to the ECM or its components without a precise understanding of how these components respond to and exert mechanical force at the nanoscale – the scale at which in idual cells respond. To address this knowledge gap, we used AFM to study the nanomechanical properties of a simple model, consisting only of type I collagen, the most abundant component of the ECM. Intriguingly, our data show bimodal distribution that is entirely attributable to type I collagen, greatly simplifying the interpretation of these studies. Furthermore, we examined the nanomechanical influence of tissue fixation by protein cross-linking, an approach commonly used in research and medical histopathology, revealing a significant and non-uniform distortion of the nanomechanical profile of fixed s les, which has the potential to introduce artifacts into the nanomechanical characterization of tissues. In contrast to the clear observation of mechanical differences induced by cross-linking, Fourier-transform infrared (FTIR) spectroscopy revealed only subtle alterations to the chemical signature of the collagen, highlighting the importance of nanomechanical approaches for the complete characterization of model systems and tissues.
Interfacial characterisation for flotation: 2. Air-water interface
Publisher: Elsevier BV
Date: 09-2018
Barriers and facilitators to implementation of outcome measures among physiotherapists in Nepal: A mixed-methods study
Publisher: Elsevier BV
Date: 11-2023
Recent Advances in Macro ATR-FTIR Microspectroscopic Technique for High Resolution Surface Characterisation at Australian Synchrotron IR Beamline
Publisher: Unpublished
Date: 2016
Spectroscopic study of ionic liquid adsorption from solution onto gold.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4CP05558F
Abstract: HMIM NTf 2 adsorbs on gold from ethanol to form a patchy bilayer. ‘Bound’ anion (filled anion) and ‘bound’ cation (filled blue) sit underneath a layer of cation (empty blue) and anion (empty orange). The IL regions are separated by oxidised gold (darker colour).
Clinimetric properties of the Nepali version of the Pain Catastrophizing Scale in individuals with chronic pain
Publisher: Informa UK Limited
Date: 2018
DOI: 10.2147/JPR.S153061
Challenges in imaging of soft layers and structures at solid surfaces using atomic force microscopy
Publisher: Thomas Telford Ltd.
Date: 09-2014
DOI: 10.1680/SI.13.00043
Abstract: Imaging of soft, deformable fluid layers and structures, such as submicron droplets and bubbles or two-dimensional fluid patches, at solid interfaces with an atomic force microscopy (AFM) is a very challenging task. In this article, the authors describe the most common imaging AFM modes and advances in tapping mode AFM imaging of soft systems, as well as discuss the most common artifacts occurring in such experiments during imaging of soft and deformable features at solid interfaces. In general, for rigid and deformable systems, images recorded with the AFM are always a convolution of the tip geometry and the shape of the features being imaged. With deformable s les, the size and shape of the imaged features can additionally be affected by the imaging parameters such as set-point or gains. In addition, AFM images can be easily misprocessed with image enhancement software, resulting in an image that does not represent real features at the surface is created. This review will highlight the necessary procedures to ensure successful and accurate image acquisition in soft features in AFM.
Influence of Lyophilization and Cryoprotection on the Stability and Morphology of Drug-Loaded Poly(ethylene glycol-b-ε-caprolactone) Micelles
Publisher: MDPI AG
Date: 21-04-2023
Abstract: Polymeric micelles are promising carriers for the delivery of poorly water-soluble drugs, providing enhanced drug solubility, blood circulation times, and bioavailability. Nevertheless, the storage and long-term stability of micelles in solution present challenges requiring the lyophilization and storage of formulations in the solid state, with reconstitution immediately prior to application. Therefore, it is important to understand the effects of lyophilization/reconstitution on micelles, particularly their drug-loaded counterparts. Herein, we investigated the use of β-cyclodextrin (β-CD) as a cryoprotectant for the lyophilization/reconstitution of a library of poly(ethylene glycol-b-ε-caprolactone) (PEG-b-PCL) copolymer micelles and their drug-loaded counterparts, as well as the effect of the physiochemical properties of different drugs (phloretin and gossypol). The critical aggregation concentration (CAC) of the copolymers decreased with increasing weight fraction of the PCL block (fPCL), plateauing at ~1 mg/L when the fPCL was .45. The blank (empty) and drug-loaded micelles were lyophilized/reconstituted in the absence and presence of β-CD (9% w/w) and analyzed via dynamic light scattering (DLS) and synchrotron small-angle X-ray scattering (SAXS) to assess for changes in aggregate size (hydrodynamic diameter, Dh) and morphology, respectively. Regardless of the PEG-b-PCL copolymer or the use of β-CD, the blank micelles displayed poor redispersibility ( % relative to the initial concentration), while the fraction that redispersed displayed similar Dh to the as-prepared micelles, increasing in Dh as the fPCL of the PEG-b-PCL copolymer increased. While most blank micelles displayed discrete morphologies, the addition of β-CD or lyophilization/reconstitution generally resulted in the formation of poorly defined aggregates. Similar results were also obtained for drug-loaded micelles, with the exception of several that retained their primary morphology following lyophilization/reconstitution, although no obvious trends were noted between the microstructure of the copolymers or the physicochemical properties of the drugs and their successful redispersion.
In Situ ATR FTIR Spectroscopic Study of the Formation and Hydration of a Fucoidan/Chitosan Polyelectrolyte Multilayer
Publisher: American Chemical Society (ACS)
Date: 07-10-2015
DOI: 10.1021/ACS.LANGMUIR.5B01812
Abstract: The formation of fucoidan/chitosan-based polyelectrolyte multilayers (PEMs) has been studied with in situ Fourier transform infrared (FTIR) spectroscopy. Attenuated total reflectance (ATR) FTIR spectroscopy has been used to follow the sequential build-up of the multilayer, with peaks characteristic of each polymer being seen to increase in intensity with each respective adsorption stage. In addition, spectral processing has allowed for the extraction of spectra from in idual adsorbed layers, which have been used to provide unambiguous determination of the adsorbed mass of the PEM at each stage of formation. The PEM was seen to undergo a transition in growth regimes during build-up: from supra-linear to linear. In addition, the wettability of the PEM has been probed at each stage of the build-up, using the captive bubble contact angle technique. The contact angles were uniformly low, but showed variation in value depending on the nature of the outer polymer layer, and this variation correlated with the overall percentage hydration of the PEM (determined from FTIR and quartz crystal microbalance data). The nature of the hydration water within the polyelectrolyte multilayer has also been studied with FTIR spectroscopy, specifically in situ synchrotron ATR FTIR microscopy of the multilayer confined between two solid surfaces. The acquired spectra have enabled the hydrogen bonding environment of the PEM hydration water to be determined. The PEM hydration water is seen to have an environment in which it is subject to fewer hydrogen bonding interactions than in bulk electrolyte solution.
Bubbles Rising In Solutions; Local And Terminal Velocities, Shape Variations And Collisions With Free Surface
Publisher: Brill
Kazimierz Małysa
Publisher: Faculty of Geoengineering, Mining and Geology, Wrocław University of Technology, Wrocław
Date: 2018
DOI: 10.5277/PPMP1800
Combining thermosensitive physical self-assembly and covalent cycloaddition chemistry as simultaneous dual cross-linking mechanisms for the preparation of injectable hydrogels with tuneable properties
Publisher: Elsevier BV
Date: 2023
Incorporation of FGF-2 into Pharmaceutical Grade Fucoidan/Chitosan Polyelectrolyte Multilayers
Publisher: MDPI AG
Date: 26-10-2020
DOI: 10.3390/MD18110531
Abstract: Biopolymer polyelectrolyte multilayers are a commonly studied soft matter system for wound healing applications due to the biocompatibility and beneficial properties of naturally occurring polyelectrolytes. In this work, a popular biopolymer, chitosan, was combined with the lesser known polysaccharide, fucoidan, to create a multilayer film capable of sequestering growth factor for later release. Fucoidan has been shown to act as a heparin-mimic due to similarities in the structure of the two molecules, however, the binding of fibroblast growth factor-2 to fucoidan has not been demonstrated in a multilayer system. This study assesses the ability of fucoidan to bind fibroblast growth factor-2 within a fucoidan/chitosan polyelectrolyte multilayer structure using attenuated total internal reflectance infrared spectroscopy and quartz crystal microbalance with dissipation monitoring. The fibroblast growth factor-2 was sequestered into the polyelectrolyte multilayer as a cationic layer in the uppermost layers of the film structure. In addition, the diffusion of fibroblast growth factor-2 into the multilayer has been assessed.
Lysozyme uptake into pharmaceutical grade fucoidan/chitosan polyelectrolyte multilayers under physiological conditions
Publisher: Elsevier BV
Date: 04-2020
DOI: 10.1016/J.JCIS.2020.01.030
Abstract: Polyelectrolyte multilayers composed of pharmaceutical grade fucoidan and chitosan have been assembled and studied in terms of their response to physiological solution conditions and the presence of lysozyme. The influence of phosphate buffered saline (PBS) solution on the multilayer was interrogated using attenuated total reflectance (ATR) Fourier transform infrared (FTIR) spectroscopy and atomic force microscopy (AFM). The combination of the techniques reveal that the polyelectrolyte multilayers swell when exposed to PBS after build-up and may include a small degree of mass loss as the film swells. The degree of swelling was influenced by the terminating layer of the multilayer. Upon exposure to lysozyme, it was observed that some deswelling occurred, as the enzyme adsorbed onto and permeated into the multilayer. The behaviour of the multilayer as a potential reservoir for lysozyme contrasts with the interaction with bovine serum albumin, which did not penetrate into the multilayer, indicating either exclusion by size or due to the overall net negative charge of the film.
Low-Bandgap Conjugated Polymer Dots for Near-Infrared Fluorescence Imaging
Publisher: American Chemical Society (ACS)
Date: 15-08-2018
Recent Advances in Macro ATR-FTIR Microspectroscopic Technique for High Resolution Surface Characterisation at Australian Synchrotron IR Beamline
Publisher: OSA
Date: 2018
Effects of internet-based pain coping skills training before home exercise for individuals with hip osteoarthritis (HOPE trial): a randomised controlled trial
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 22-05-2018
DOI: 10.1097/J.PAIN.0000000000001281
Abstract: This assessor-, therapist-, and participant-blinded randomised controlled trial evaluated the effects of an automated internet-based pain coping skills training (PCST) program before home exercise for people with clinically diagnosed hip osteoarthritis. One hundred forty-four people were randomised to either the PCST group or the comparator group. In the first 8 weeks, the PCST group received online education and PCST, whereas the comparison group received online education only. From weeks 8 to 24, both groups visited a physiotherapist 5 times for home exercise prescription. Assessments were performed at baseline, 8, 24, and 52 weeks. Primary outcomes were hip pain on walking (11-point numerical rating scale) and physical function (Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC]) at 24 weeks. Secondary outcomes were other measures of pain, quality-of-life, global change, self-efficacy, pain coping, pain catastrophizing, depression, anxiety, stress, physical activity, and adverse events. Primary outcomes were completed by 137 (95%), 131 (91%), and 127 (88%) participants at 8, 24, and 52 weeks, respectively. There were no significant between-group differences in primary outcomes at week 24 (change in: walking pain [mean difference 0.5 units 95% confidence interval, −0.3 to 1.3] and function [−0.9 units 95% confidence interval, −4.8 to 2.9]), with both groups showing clinically relevant improvements. At week 8, the PCST group had greater improvements in function, pain coping, and global improvement than comparison. Greater pain coping improvements persisted at 24 and 52 weeks. In summary, online PCST immediately improved pain coping and function but did not confer additional benefits to a subsequent exercise program, despite sustained pain coping improvements.
Air-Facilitated Three-Phase Contact Formation at Hydrophobic Solid Surfaces under Dynamic Conditions
Publisher: American Chemical Society (ACS)
Date: 22-11-2006
DOI: 10.1021/LA062320N
Abstract: The paper presents results documenting the mechanism of facilitation of the three-phase contact (TPC) formation due to gas entrapped during immersion of hydrophobic (Teflon) plates into distilled water and n-octanol solutions. Collisions, bouncing, the time scale of the TPC formation, and bubble attachment to Teflon plates of different surface roughness were studied using a high-speed camera. Processes occurring during the microscopic wetting film formation at the Teflon plates were monitored using the microinterferometric method (Scheludko-Exerowa cell). A strong relation between the time necessary to form a stable TPC and the roughness of the Teflon was observed. The higher the Teflon roughness was the shorter the time for the TPC formation. This effect can be attributed to two factors: (i) local differences in the thickness of the thinning intervening liquid layer (quicker attainment of rupture thickness at pillars of rough surface) and/or (ii) the presence of gas at the hydrophobic surface. Experimental findings, that (i) prolongation of the plate immersion time resulted in quicker TPC formation, (ii) white irregular and disappearing spots (air pockets) were recorded during the wetting film formation, and (iii) high n-octanol concentration caused prolongation of the time of the TPC formation, show that attachment (TPC formation) of the colliding bubble to hydrophobic surfaces was facilitated by air entrapped at the Teflon plates (and re-distributed) during their immersion into water phase. Thus, on collision instead of solid/gas wetting liquid film a thin gas/liquid/gas foam film was formed which facilitated the TPC formation.
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