Probing crystallisation of a fluoro-apatite - mullite system using neutron diffraction

Real-time small angle neutron scattering and wide angle neutron scattering studies were undertaken concurrently on a glass ionomer of nominal composition 4.5(SiO2)-3(Al2O3)-1.5(P2O5)-3(CaO)-2(CaF2). Neutron studies were conducted as a function of temperature to investigate the crystallisation process. No amorphous phase separation was observed at room temperature and the onset of crystallisation was found to occur at 650°C, which is 90°C lower than previously reported. The first crystalline phase observed corresponded to fluorapatite; it was only upon further heating was the mullite phase became present. The crystallite size at 650°C was found to be ~115Å and the result was consistent across all measurements

A local dynamic correlation function from inelastic neutron scattering

Information about local and dynamic atomic correlations can be obtained from inelastic neutron scattering measurements by Fourier transform of the Q-dependent intensity oscillations at a particular frequency. A local dynamic structure function, S(r,{omega}), is defined from the dynamic scattering function, S(Q,{omega}), such that the elastic and frequency-integrated limits correspond to the average and instantaneous pair-distribution functions, respectively. As an example, S(r,{omega}) is calculated for polycrystalline aluminum in a model where atomic motions are entirely due to harmonic phonons

The Effect of Pravastatin on Intima Media Thickness of the Carotid Artery in Patients with Normal Cholesterol

AbstractObjectiveCarotid intima media thickness (IMT) is a good indicator of the severity of atherosclerotic disease. Statins have been found to reduce carotid IMT in patients with hypercholesterolaemia. The aim of this study was to investigate if pravastatin is effective in reducing IMT in normocholesterolaemic patients with carotid artery disease.MethodsPatients with carotid artery stenosis and normal cholesterol levels who were not on a statin, were recruited. Patients were randomised to receive pravastatin or placebo daily. Serum concentration of cholesterol and IMT of common carotid arteries were measured before randomisation and at 3 monthly intervals thereafter, for 9 months. IMT was analysed to give the mean of a standardised 2cm of the common carotid artery (CCA). Results are expressed as median (IQR) and comparison made using the Wilcoxon signed ranks test.ResultsFifty-four patients were examined. Twenty-eight patients were randomised to active treatment. There was no difference in demographic details and co-morbid states between the two groups. A significant reduction in cholesterol concentration was observed from 3 months in patients randomised to the pravastatin group [5.14(4.72–5.88) vs. 4.11(3.44–5.33), p<0.05], while there was also a significant decrease in combined IMT form 6 months [1.53(1.36–1.87) vs. 1.41 (1.33–1.78), p<0.05].ConclusionsThe results demonstrate that pravastatin reduces intima media thickness of the common carotid artery in normocholesterolaemic patients with moderate carotid stenosis

Strategies for Controlled Placement of Nanoscale Building Blocks

The capability of placing individual nanoscale building blocks on exact substrate locations in a controlled manner is one of the key requirements to realize future electronic, optical, and magnetic devices and sensors that are composed of such blocks. This article reviews some important advances in the strategies for controlled placement of nanoscale building blocks. In particular, we will overview template assisted placement that utilizes physical, molecular, or electrostatic templates, DNA-programmed assembly, placement using dielectrophoresis, approaches for non-close-packed assembly of spherical particles, and recent development of focused placement schemes including electrostatic funneling, focused placement via molecular gradient patterns, electrodynamic focusing of charged aerosols, and others

The redistributed water and electrolytes across the cell membrane in sepsis with reference to the clinical syndrome of hyponatraemia

SIGLEAvailable from British Library Document Supply Centre- DSC:DXN1476 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Rectal Passage of Full-thickness Infarcted Left Colon Post-endovascular Stenting of Abdominal Aortic Aneurysm—Report of a Case

AbstractWe report a case of a full-thickness colonic infarction post-EVAR, manifested by a prolonged period of refractory culture-negative diarrhoea culminating in the passing a 90cm length of full thickness colon per rectum on the 34th post-operative day. Passage of an infarcted sigmoid colon ‘cast’ has been reported after open repair of an abdominal aortic aneurysm, but has not been reported after endovascular stent repair

Extraperitoneal approach reduces neutrophil activation, systemic inflammatory response and organ dysfunctionin aortic aneurysm surgery.

AbstractObjectives: to compare the effects of transperitoneal and extraperitoneal approaches on systemic inflammatory response, neutrophil activation and organ dysfunction in elective abdominal aortic aneurysm (AAA) repair.Patients and methods: twenty patients admitted for elective infrarenal AAA repair were prospectively randomised into transperitoneal (n =10) or extraperitoneal ( n =10) groups. Neutrophil activation was assessed by measuring the plasma levels of neutrophil elastase/α1-anti-trypsin complexes before surgery, intraoperatively and at 6 h, 12 h, 24 h and then daily after surgery. Venous blood samples for estimation of liver function tests, full blood counts, urea and electrolytes and arterial samples for blood gas analysis were taken daily from preoperatively to day 5 after surgery. Multiple organ dysfunction (MOD) and systemic inflammatory response (SIR) scores were calculated daily.Results: the concentrations of neutrophil elastase/α1-anti-trypsin complexes were significantly higher in the transperitoneal group at 6 h after surgery compared to the extraperitoneal group (799(455–921) ng/ml (median(i.q.r.)) vs 307(171–395) ng/ml, p<0.005), and at 12 h (397(364–936) ng/ml vs 319(134–352) ng/ml, p <0.05). The MOD scores were significantly higher in the transperitoneal group in comparison to the extraperitoneal group at day 1 (2.5(2–3.3) vs 1(0–1), p<0.001) and day 2 (2.5(2–3.3) vs 1(0–1), p <0.001). The SIR scores were also significantly higher at day 1 (1(0–2) vs 0, p<0.01), day 2 (1.5(0–2.3) vs 0, p <0.01), and day 3 (1(0–1) vs 0, p <0.05). Conclusions: neutrophil activation, systemic inflammatory response and organ dysfunction are increased in elective AAA repair when a transperitoneal approach is used. This may be related to intestinal manipulation and mesenteric traction which are reduced in the extraperitoneal approach