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Sheffield, United Kingdom

Tadjiev D.R.,University of Sheffield | Hand R.J.,University of Sheffield | Zeng P.,Kroto Research Institute
Materials Letters

The thicknesses of the hydration layers on the surfaces of 2 silicate glasses have been assessed using a) a combination of focused ion beam milling and transmission electron microscopy and b) nanoindentation; the two approaches give consistent layer thicknesses. Lighter contrast of the hydrated layers in TEM suggests that the layers have reduced density when compared to the bulk glasses; this is consistent with the reduced near surface modulus and hardness of hydrated glasses observed in nanoindentation. © 2010 Elsevier B.V. All rights reserved. Source

El-Azizi I.M.,Tajoura Research Center | Schmalenberger A.,University of Sheffield | Komlenic R.,Kroto Research Institute | Edyvean R.G.J.,Alstrom Filtration LLC
Desalination and Water Treatment

The removal efficiency of a nanoalumina depth filter (Disruptor™) was tested using raw seawater from the North Sea in a laboratory scale filtration unit and reverse osmosis (RO) test unit. Permeate flux was measured against time using untreated and pre-filtered seawater. Untreated seawater exhibited a rapid permeate flux decline. Seawater pre-filtered through the Disruptor™ showed showed high flux that declined only slightly after 120 min of operation due to increasing of osmotic pressure and formation of scaling on the membrane surface. The surface morphologies of clean and fouled RO membranes were examined using scanning electron microscope (SEM). The surface of the membrane fouled by untreated seawater was completely covered by a fouling layer, while the membrane surfaces exposed to Disruptor™ pre-filtered seawater were clean and only scaling was detected. The functional groups on clean and fouled RO membrane samples were investigated by attenuated total reflection - Fourier transform infrared spectroscopy (ATR-FTIR). The spectra of the RO membrane fouled by untreated seawater showed absorption bands at 1025, 1006 and 915 cm-1, indicating that the fouling materials were polysaccharides and silica clay materials. The spectrum on the RO membrane exposed to pre-filtered seawater through the Disruptor™ was indistinguishable from that of the clean RO membrane. The involvement of transparent exopolymer particles (TEP) in the establishment of biofouling and development of biofilm was investigated. Results showed that TEP size increased as well as the number of bacteria with time of incubation. However, the number of TEP decreased by about 80% in seawater pre-filtered through the Disruptor™. © 2011 Desalination Publications. All rights reserved. Source

Bullock A.J.,Kroto Research Institute | Pickavance P.,University of Sheffield | Haddow D.B.,York Pharma | Rimmer S.,University of Sheffield | MacNeil S.,Kroto Research Institute
Regenerative Medicine

Aims: Superficial burns and scalds are usually managed conservatively with traditional dressings. Failure to heal within 3 weeks leads to their management by skin grafting. Our aim was to develop a biomaterial to actively promote keratinocyte migration in superficial burns by modulating local cation concentrations to accelerate keratinocyte migration and deter wounds from contracting, thus potentially reducing the number of such wounds requiring grafting. Materials & methods: We investigated polymeric hydrogels for their Ca2+ chelating properties and enhancement of keratinocyte migration in human tissue-engineered skin models. Results: Dimethylaminoethyl methacrylate:methacrylic acid hydrogel coupled with elevated [Mg2+] reduced media [Ca2+], potentiating keratinocyte migration in tissue-engineered skin models, it also significantly reduced wound model contraction. Conclusion: Dimethylaminoethyl methacrylate:methacrylic acid hydrogels could promote wound healing and reduce wound contraction, a significant complication in burn wound healing. © 2010 Future Medicine Ltd. Source

Sefat F.,Kroto Research Institute | McKean R.,Rutherford Appleton Laboratory | Deshpande P.,Kroto Research Institute | Ramachandran C.,LV Prasad Eye Institute LVPEI | And 4 more authors.
Procedia Engineering

Our aim was to produce, sterilize and store a synthetic, rapidly biodegrading membrane for cultured limbal stem cell transplantation. Membranes were electrospun from Poly(D, L-lactide-co-glycolide) with a 50:50 ratio of lactide and glycolide comparing 44 kg/mol and 153 kg/mol molecular weights (MW) and sterilized with y-irradiation and stored for up to a year at a range of temperatures. Cells attached well on both MW membranes. The lower MW degraded faster than the higher MW membranes. y-irradiation accelerated membrane breakdown when wet but sterilised membranes could be stored dry for at least a year at -20°C. © 2013 The Authors. Source

Kasaragod D.K.,Kroto Research Institute | Lu Z.,Kroto Research Institute | Smith L.E.,Kroto Research Institute | Matcher S.J.,Kroto Research Institute
Proceedings of SPIE - The International Society for Optical Engineering

Optical coherence tomography (OCT) is an imaging technique based on the low coherence interferometry, in which signals are obtained based on the coherent addition of the back reflected light from the sample. Applying computational methods and automated algorithms towards the classification of OCT images allows a further step towards enhancing the clinical applications of OCT. One attempt towards classification could be achieved by statistically analyzing the texture of the noisy granular patterns - speckles that make the OCT images. An attempt has been made to quantify the scattering effects based on the speckle texture patterns the scatterers produce. Statistical inference is drawn from the textural analysis of the features based on the spatial intensity distribution on the agar phantoms with different concentration of Intralipid solutions. This preliminary study conducted on agar-Intralipid solution has showed us that it is possible to differentiate between different types of scatterers based on the speckle texture studies. The texture analysis has also been extended in an attempt to identify the invasion of melanoma cell into tissue engineered skin. However using the same approach of texture analysis, we have not obtained satisfactory results for carrying on with the computer-based identification of the invasion of the melanoma in the tissue engineered skin, the reason for which has to be further studied and investigated upon. © 2010 Copyright SPIE - The International Society for Optical Engineering. Source

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