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Fredholm Y.C.,Imperial College London | Karpukhina N.,Imperial College London | Law R.V.,Imperial College London | Hill R.G.,Barts and The London
Journal of Non-Crystalline Solids | Year: 2010

The influence of substituting strontium for calcium in the following glass series 49.46 SiO2-1.07 P2O5-(23.08-X) CaO-X SrO-26.38 Na2O was studied on the physical properties. Solid state nuclear magnetic resonance and vibrational spectroscopy showed that the glasses were predominantly composed of Q2 silicate chains. Addition of strontium did not result in any structural alteration of the glass network due to the similar role of SrO compared with that of CaO. The density increased with strontium content whilst the oxygen density decreased indicating a more expanded glass network. The glass transition temperature reduced with strontium substitution in a linear fashion and there was no evidence of a mixed alkaline earth effect with a lower than expected glass transition temperature. Dilatometric softening points also reduced with increasing strontium content, whilst the thermal expansion coefficients increased. The results are consistent with a weaker network as a result of the lower charge to size ratio of Sr 2+ compared to Ca2+. © 2010 Elsevier B.V. All rights reserved.


Brauer D.S.,Imperial College London | Karpukhina N.,Imperial College London | O'Donnell M.D.,BioCeramic Therapeutics | Law R.V.,Imperial College London | Hill R.G.,Barts and The London
Acta Biomaterialia | Year: 2010

Bioactive glasses are able to bond to bone through formation of carbonated hydroxyapatite in body fluids, and fluoride-releasing bioactive glasses are of interest for both orthopaedic and, in particular, dental applications for caries inhibition. Melt-derived glasses in the system SiO 2-P 2O 5-CaO-Na 2O with increasing amounts of CaF 2were prepared by keeping network connectivity and the ratio of all other components constant. pH change, ion release and apatite formation during immersion of glass powder in simulated body fluid at 37 °C over up to 2 weeks were investigated. Crystal phases formed in SBF were characterized using infrared spectroscopy, X-ray diffraction with Rietveld analysis and solid-state nuclear magnetic resonance spectroscopy ( 19F and 31P MAS-NMR). Results show that incorporation of fluoride resulted in a reduced pH rise in aqueous solutions compared to fluoride-free glasses and in formation of fluorapatite (FAp), which is more chemically stable than hydroxyapatite or carbonated hydroxyapatite and therefore is of interest for dental applications. However, for increasing fluoride content in the glass, fluorite (CaF 2) was formed at the expense of FAp. Apatite formation could be favoured by increasing the phosphate content in the glass, as the release of additional phosphate into the SBF would affect supersaturation in the solution and possibly favour formation of apatite. © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.


Milburn H.,The London Clinic | Ashman N.,Barts and the London Renal Center | Davies P.,Liverpool NHS Trust | Doffman S.,Brighton General Hospital | And 5 more authors.
Thorax | Year: 2010

Guidelines have been compiled by the Joint Tuberculosis Committee of the British Thoracic Society for the prevention and management of Mycobacterium tuberculosis infection and disease in patients with all grades of renal impairment.


Kelly P.,Barts and The London
Medicine (United Kingdom) | Year: 2013

Human intestinal protozoal infections are found worldwide. Protozoa produce diarrhoeal disease by infecting the small or large intestine, or both. Amoebiasis is an important cause of dysentery and liver abscess worldwide. Giardiasis and cryptosporidiosis are important causes of diarrhoea in children; the latter is particularly associated with growth failure and malnutrition. They also cause water-borne and food-borne outbreaks. Food-borne outbreaks may also be caused by Cyclospora cayetanensis. The importance of intestinal protozoa has increased with the HIV/AIDS pandemic, which led to the recognition of new protozoal pathogens. Recently, the frequency of severe opportunistic intestinal protozoal infection has decreased because of large programmes of anti-retroviral therapy. Intestinal protozoa are difficult to identify but molecular and antigen-based tests are beginning to be adopted. Many protozoa respond readily to well-established antibiotics but some (particularly cryptosporidiosis) can be difficult to treat, especially in immunocompromised patients. Recently, molecular biological work has helped to clarify the classification of these parasites and, more importantly, is beginning to unlock features of their biology that may help in prevention. © 2013 Elsevier Ltd. All rights reserved.


Wang Y.,Barts and The London
Journal of Medical Ethics | Year: 2016

The discourse on the failings of the National Health System often cites lack of compassion as an important factor. This has resulted in proposals to enact rules which aimed at enforcing compassion in healthcare workers so as to improve the quality of healthcare and avoid future scandals. This paper argues that compassion cannot be enforced by any rule. Moreover, the contractual nature of the current doctor-patient relationship does not foster it. Experience from other service industries shows that attempts to enforce compassion in workers are futile. Rather than improving service, these attempts result in a culture of perfunctoriness and cynicism.

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