The room temperature phosphine-free synthesis of near-infrared emitting HgSe quantum dots

Luminescent mercury selenide (HgSe) quantum dots have been synthesised by a phosphine-free method using oleic acid as a capping agent. The modification of experimental conditions such as temperature resulted in particles of various sizes (15–100 nm) and morphologies not previously seen in HgSe, with emission tuneable between 1000 nm and 1350 nm

On the Lichnerowicz conjecture for CR manifolds with mixed signature

We construct examples of nondegenerate CR manifolds with Levi form of signature $(p,q)$, $2\leq p\leq q$, which are compact, not locally CR flat, and admit essential CR vector fields. We also construct an example of a noncompact nondegenerate CR manifold with signature $(1,n-1)$ which is not locally CR flat and admits an essential CR vector fields. These provide counterexamples to the analogue of the Lichnerowicz conjecture for CR manifolds with mixed signature.Comment: 7 page

Optical Studies of Er-doped Yttrium Aluminium Garnet Phosphor Materials

The need for materials application in solid-state lasers, medical devices, and optoelectronic devices has made the investigation of ceramic materials of increasing importance. A detail study of the optical properties of rare earth element typically from luminescent materials when intentionally doped inside the host materials and in particular crystal (such as YAG) is reported for the photoluminescence, power and lifetime measurement. The rare-earth dopants usually form trivalent lanthanide ions and the energy transfer and optical transitions involved originate from 4f-4f transitions of the ions and between these states and the host material. In order to understand the energy transfer processes in more detail we need to better understand the accompanying optical processes that give rise to the emission they display and it is this that forms the focus of the work presented. Following this second (and higher) order processes are considered that lead to upconversion in erbium-doped yttrium aluminum garnet (Er:YAG) materials

The acute management of trauma hemorrhage: a systematic review of randomized controlled trials.

PublishedResearch Support, Non-U.S. Gov'tReviewINTRODUCTION: Worldwide, trauma is a leading cause of death and disability. Haemorrhage is responsible for up to 40% of trauma deaths. Recent strategies to improve mortality rates have focused on optimal methods of early hemorrhage control and correction of coagulopathy. We undertook a systematic review of randomized controlled trials (RCT) which evaluated trauma patients with hemorrhagic shock within the first 24 hours of injury and appraised how the interventions affected three outcomes: bleeding and/or transfusion requirements; correction of trauma induced coagulopathy and mortality. METHODS: Comprehensive searches were performed of MEDLINE, EMBASE, CENTRAL (The Cochrane Library Issue 7, 2010), Current Controlled Trials, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Platform (ICTRP) and the National Health Service Blood and Transplant Systematic Review Initiative (NHSBT SRI) RCT Handsearch Database. RESULTS: A total of 35 RCTs were identified which evaluated a wide range of clinical interventions in trauma hemorrhage. Many of the included studies were of low methodological quality and participant numbers were small. Bleeding outcomes were reported in 32 studies; 7 reported significantly reduced transfusion use following a variety of clinical interventions, but this was not accompanied by improved survival. Minimal information was found on traumatic coagulopathy across the identified RCTs. Overall survival was improved in only three RCTs: two small studies and a large study evaluating the use of tranexamic acid. CONCLUSIONS: Despite 35 RCTs there has been little improvement in outcomes over the last few decades. No clear correlation has been demonstrated between transfusion requirements and mortality. The global trauma community should consider a coordinated and strategic approach to conduct well designed studies with pragmatic endpoints.This research project was funded by the National Institute for Health Research Programme Grant for Applied Research (RP-PG-0407-10036)

Clinical outcomes of a treat and extend regimen with intravitreal aflibercept injections in patients with diabetic macular edema: Experience in clinical practice

Introduction: Treat-and-extend (T&E) and prore nata (PRN; ‘as needed’) regimens of intravitreal anti-vascular endothelial growth factor(VEGF) treatment have been found to reducethe injection burden on patients and improvethe cost effectiveness of the treatment of macular edema. The aim of this study was to assessthe effectiveness of a T&E regimen of aflibercept, in a clinical setting, in patients with diabetic macular edema (DME) who were either intravitreal anti-VEGF therapy naive or withminimal exposure to anti-VEGF (B 6 treatments) in the previous 12 months.Methods: This prospective, single arm, open labelstudy recruited patients with DME (macularthickness of C 300 lm) and best-corrected visualacuity (BCVA) between 28-78 ETDRS letters. Participants received five loading doses of intravitrealaflibercept at 4-weekly intervals. BCVA measurements and macular optical coherence tomographywere performed at each visit. If no disease activitywas detected, treatment intervals were increased by2 weeks to a maximum of 12 weeks. Outcomemeasures included: changes in BCVA and retinalanatomical measures (central foveal thickness[CFT] and central macular volume within 6 mm ofthe fovea [CSVol]) between baseline and 2 years,patient treatment intervals; and adverse events.Results: Of the 36 patients who providedinformed consent to participate in the studyand were screened, 26 patients (eyes) were eligible to participate in the study. After regressionanalysis, adjustment for repeated measures, andsignificant covariates, the mean BCVA increasedby 3.8 letters (95% confidence interval [CI] 1.1,6.4) and the CFT and CSVol decreased by127.2 lm (95% CI 91.7, 162.5) and 1.6 mm3 (95% CI 1.2, 2.0), respectively, over the courseof the study. In the second year, 16 of the 25patients still participating had their treatmentintervals extended to 12 weeks. There was noevidence of any new adverse events that wouldrequire changes to the aflibercept safety profile.Conclusion: For the majority of patients presenting with DME, a T&E regimen of afliberceptin the first 2 years of therapy is a practical alternative to PRN treatment with regular review

Structural Insights into Differences in Drug-binding Selectivity between Two Forms of Human α1-Acid Glycoprotein Genetic Variants, the A and F1*S Forms

Human α1-acid glycoprotein (hAGP) in serum functions as a carrier of basic drugs. In most individuals, hAGP exists as a mixture of two genetic variants, the F1*S and A variants, which bind drugs with different selectivities. We prepared a mutant of the A variant, C149R, and showed that its drug-binding properties were indistinguishable from those of the wild type. In this study, we determined the crystal structures of this mutant hAGP alone and complexed with disopyramide (DSP), amitriptyline (AMT), and the nonspecific drug chlorpromazine (CPZ). The crystal structures revealed that the drug-binding pocket on the A variant is located within an eight-stranded β-barrel, similar to that found in the F1*S variant and other lipocalin family proteins. However, the binding region of the A variant is narrower than that of the F1*S variant. In the crystal structures of complexes with DSP and AMT, the two aromatic rings of each drug interact with Phe-49 and Phe-112 at the bottom of the binding pocket. Although the structure of CPZ is similar to those of DSP and AMT, its fused aromatic ring system, which is extended in length by the addition of a chlorine atom, appears to dictate an alternative mode of binding, which explains its nonselective binding to the F1*S and A variant hAGPs. Modeling experiments based on the co-crystal structures suggest that, in complexes of DSP, AMT, or CPZ with the F1*S variant, Phe-114 sterically hinders interactions with DSP and AMT, but not CPZ. © 2011 by The American Society for Biochemistry and Molecular Biology, Inc

Resolution requirements for numerical simulations of transition

The resolution requirements for direct numerical simulations of transition to turbulence are investigated. A reliable resolution criterion is determined from the results of several detailed simulations of channel and boundary-layer transition