Lubricin is a glycoprotein found in articular joints which has been long recognized as being an important biological boundary lubricant molecule and, more recently, and impressive anti-adhesive that readily self-assembles into a well... more
Lubricin is a glycoprotein found in articular joints which has been long recognized as being an important biological boundary lubricant molecule and, more recently, and impressive anti-adhesive that readily self-assembles into a well ordered, polymer brush layer on virtually any substrate. The lubricin molecule possesses an overabundance of anionic charge, a property that is atypical among anti-adhesive molecules, that enables its use as a coating for applications involving electrokinetic processes such as electrophoresis and electroosmosis. Coating the surfaces of silica and polymeric microfluidic devices with self-assembled lubricin coatings affords a unique combination of excellent fouling resistance and high charge density that enables notoriously 'sticky' biomolecules such as proteins to be used and controlled electrokinetically in the device without complications arising from non-specific adsorption. Using capillary electrophoresis, we characterized the stability, uniformity, and electrokinetic properties of lubricin coatings applied to silica and PTFE capillaries over a range of run buffer pHs and when exposed to concentrated solutions of protein. In addition, we demonstrate the effectiveness of lubricin as a coating to minimize non-specific protein adsorption in an electrokinetically controlled polydimethyl siloxane/silica microfluidic device.
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Researchers have developed techniques for multi-layered fabrication of microfluidic chips which allow for increased scope of channel geometries and associated improved sensing capabilities. In these techniques, slits have been fabricated... more
Researchers have developed techniques for multi-layered fabrication of microfluidic chips which allow for increased scope of channel geometries and associated improved sensing capabilities. In these techniques, slits have been fabricated in thin layers of polymer or ...
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Polygodial, a valuable sesquiterpene dialdehyde featuring an epimerizable stereocenter was efficiently extracted and isolated in gram-scale quantities (3.3% w/w) from Tasmannia lanceolata (Tasmanian native pepper) via a recently developed... more
Polygodial, a valuable sesquiterpene dialdehyde featuring an epimerizable stereocenter was efficiently extracted and isolated in gram-scale quantities (3.3% w/w) from Tasmannia lanceolata (Tasmanian native pepper) via a recently developed rapid pressurised hot water extraction (PHWE) technique that utilises an unmodified household espresso machine. This method was compared to the maceration of T. lanceolata under a range of conditions. Polygodial was used to achieve semi-syntheses of closely related sesquiterpene natural products drimendiol, (-)-drimenol, (+)-euryfuran, and some non-natural derivatives.
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The application of mobile phase gradients in liquid chromatography allows the separation of weakly retained and strongly retained analytes within a reasonable timeframe, significantly increases peak capacity and in many instances can lead... more
The application of mobile phase gradients in liquid chromatography allows the separation of weakly retained and strongly retained analytes within a reasonable timeframe, significantly increases peak capacity and in many instances can lead to marked improvements in sensitivity due to chromatographic peak focussing.
Cobalt magnetic nanoparticles surface functionalised with iminodiacetic acid were evaluated as a nano-particulate solid phase extraction absorbent for copper ions (Cu(2+)) from environmental water samples. Using an external magnetic... more
Cobalt magnetic nanoparticles surface functionalised with iminodiacetic acid were evaluated as a nano-particulate solid phase extraction absorbent for copper ions (Cu(2+)) from environmental water samples. Using an external magnetic field, the collector nanoparticles could be separated from the aqueous phase, and adsorbed ions simply decomplexed using dilute HNO3. Effects of pH, buffer concentration, sample and sorbent volume, extraction equilibrium time, and interfering ion concentration on extraction efficiency were investigated. Optimal conditions were then applied to the extraction of Cu(2+) ions from natural water samples, prior to their quantitation using high-performance chelation ion chromatography. The limits of detection (LOD) of the combined extraction and chromatographic method were ~0.1 ng ml(-1), based upon a 100-fold preconcentration factor (chromatographic performance; LOD=9.2 ng ml(-1) Cu(2+)), analytical linear range from 20 to 5000 ng mL(-1), and relative standard...
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A curing system comprising an oven which may be usefully employed in the fabrication of long polymer columns of various morphologies and formats is described. In accordance with an exemplary arrangement the invention relates to a curing... more
A curing system comprising an oven which may be usefully employed in the fabrication of long polymer columns of various morphologies and formats is described. In accordance with an exemplary arrangement the invention relates to a curing system comprising an oven that allows for the formation of very long capillary columns.
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ABSTRACT This work has investigated the ionic composition of precipitation samples based on measuring Na+, K+, Mg2+, Ca2+, Cl-, SO4-S, NH4-N, NO3-N (mg/L) and the trends of SO2-S, SO4-S, and NO2-N (µg/m3) concentrations in air samples... more
ABSTRACT This work has investigated the ionic composition of precipitation samples based on measuring Na+, K+, Mg2+, Ca2+, Cl-, SO4-S, NH4-N, NO3-N (mg/L) and the trends of SO2-S, SO4-S, and NO2-N (µg/m3) concentrations in air samples collected on a daily basis at Valentia Observatory, Cahirciveen, Co. Kerry, Ireland and analysed in the Met Éireann laboratory over the period 1980 - 2004. The time series of annual average SO2-S and SO4-S concentrations (µg/m3) for the air data shows a distinct downward trend. The NO2-N concentration (µg/m3) levels have remained relatively stable since measurements commenced in 1989. No such obvious trends are visible from the original precipitation data; however, by investigating the contribution of sea-salt sulphate to the total sulphate levels it is possible to conclude that the non-sea salt sulphate levels (i.e. anthropogenic contribution) have decreased since the measurements have commenced. The location of the site on the south west coast results in exposure to the Atlantic Ocean and this results in considerable contribution of ions from the sea that is clearly shown from the wind sector analysis of the precipitation samples for Na+, K+, Mg2+, Ca2+ and Cl-. The air data shows that the highest concentrations for the SO2-S and SO4-S and NO2-N are correlated with winds coming from an easterly and northeasterly direction (which is also confirmed from the non-sea salt sulphate levels for the precipitation results). The lowest concentrations were found for westerly directions. This has also been proven correct with the use of back trajectory analysis, which has allowed tracing the movement of air parcels using ECMWF analysis fields. Keywords: background air concentration, precipitation, sulphur dioxide, sulphate, nitrogen dioxide, calcium, magnesium, sodium, sea-salt sulphate, anthropogenic sources.
ABSTRACT The nature of the ‘compositional space’ of van Krevelen diagrams of Dissolved Organic Matter is discussed in relation to a recently published major review.
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Research Interests: Electrophoresis and A
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ABSTRACT The ion-exchange properties of a new mixed-bed ion-exchange column Scherzo SSC18 (Imtakt, USA) were investigated. This mixed-mode column is packed with two types of 3 µm spherical silica particles having either octadecyl- and... more
ABSTRACT The ion-exchange properties of a new mixed-bed ion-exchange column Scherzo SSC18 (Imtakt, USA) were investigated. This mixed-mode column is packed with two types of 3 µm spherical silica particles having either octadecyl- and strong cation-exchange functional groups or octadecyl- and strong anion-exchange functional groups. The regularities of the retention of alkali metal cations and inorganic anions were studied with diluted acids (sulfuric, perchloric to phosphoric, nitric, oxalic and citric acids) as eluents and direct conductivity for the detection. Eluent concentration, column temperature and organic solvent addition effects were investigated. The separations were achieved on the basis of ion-exchange interactions introduced by the strong anion and strong cation-exchange functionalities of the stationary phase; meanwhile, contribution of hydrophobic interactions was also evident for the hydrophobic iodide and thiocyanate. The simultaneous separation of 12 inorganic anions and cations in 20 min was obtained under isocratic conditions with 1 mM oxalic acid as eluent. The applicability of developed method to the determination of chloride, sodium, potassium as well as nitrite, nitrate and ammonium in soil extracts was demonstrated with good potential for nitrogen speciation studies.
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ABSTRACT In the present work microwave-assisted purification approaches for detonation nanodiamond (DND) are considered, and the resultant impurity content of purified DND revealed by direct ICP-MS and elemental analysis. A significant... more
ABSTRACT In the present work microwave-assisted purification approaches for detonation nanodiamond (DND) are considered, and the resultant impurity content of purified DND revealed by direct ICP-MS and elemental analysis. A significant reduction in noncarbon contaminants as compared with detonation soot was achieved with resulting purity of 99.95 %. Surface characterisation including scanning electronic microscopy, low temperature adsorption of nitrogen, acid-base potentiometric titration, zeta potential measurements and particle size distribution of the DND in suspensions revealed distinctive surface properties for each purified DND sample. Results highlight the suitability of the microwave purification approach using acid reagents, allowing nanodiamonds with different and reproducible surface properties to be produced or modified. Contamination effects from laboratory glassware used to store samples were carefully considered. Refined DND with impurity levels over two orders of magnitude lower than commercially available samples was prepared. The profile and concentration levels of residual impurities in purified samples of nanodiamond are discussed with identification of possible reasons for contamination.
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Research Interests: Air Quality, Environmental Monitoring, Risk assessment, Ireland, Cities, and 14 moreEnvironmental Sciences, Air, Nitrates, Metals, CHEMICAL SCIENCES, Chemical Precipitation, Particle Size, Risk Assessment, Quaternary Ammonium Compounds, Nitrogen Dioxide, Sulfur Dioxide, Air Pollutants, Sulfates, and Chlorides
This report has been prepared through the Environmental Research Centre, a measure of the ERTDI Programme which is financed by the Irish Government under the National Development Plan 20002006. It is administered on behalf of the... more
This report has been prepared through the Environmental Research Centre, a measure of the ERTDI Programme which is financed by the Irish Government under the National Development Plan 20002006. It is administered on behalf of the Department of the Environment, ...
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A new, practical, rapid, and high-yielding process for the pressurized hot water extraction (PHWE) of multigram quantities of shikimic acid from star anise (Illicium verum) using an unmodified household espresso machine has been... more
A new, practical, rapid, and high-yielding process for the pressurized hot water extraction (PHWE) of multigram quantities of shikimic acid from star anise (Illicium verum) using an unmodified household espresso machine has been developed. This operationally simple and inexpensive method enables the efficient and straightforward isolation of shikimic acid and the facile preparation of a range of its synthetic derivatives.