224 research outputs found

    Investigating the suitability of carbon nanotube reinforced polymer in transcatheter valve applications

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    The current delivery size of transcatheter aortic valves, limited by the thickness of their pericardial leaflets, correlates with a high prevalence of major vascular complications. Polyurethane valves can be developed to a fraction of the thickness of pericardial valves through the addition of carbon nanotubes to reinforce their leaflets. This study investigates the suitability of a novel carbon nanotube reinforced leaflet to reduce the delivery profile of transcatheter aortic valves. Carbon nanotube polyurethane composites were developed with thicknesses of 50 μm and their mechanical properties were determined in relation to various environmental effects. The composites demonstrated improvements to the material stiffness, particularly at increasing strain rates compared to the neat polymer. However, increasing nanotube concentrations significantly decreased the fatigue life of the composites. Key findings highlighted a potential for carbon nanotube reinforcement in valve replacement which experience very high strain rates during the cardiac cycle. Further testing is needed to achieve a strong nanotube-matrix interface which will prolong the cyclic fatigue life and further strengthen tensile properties. Testing on the durability and haemocompatibility of these composite heart valves are ongoing

    Protein associated with SMAD1 (PAWS1/FAM83G) is a substrate for type I bone morphogenetic protein receptors and modulates bone morphogenetic protein signalling

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    Bone morphogenetic proteins (BMPs) control multiple cellular processes in embryos and adult tissues. BMPs signal through the activation of type I BMP receptor kinases, which then phosphorylate SMADs 1/5/8. In the canonical pathway, this triggers the association of these SMADs with SMAD4 and their translocation to the nucleus, where they regulate gene expression. BMPs can also signal independently of SMAD4, but this pathway is poorly understood. Here, we report the discovery and characterization of PAWS1/FAM83G as a novel SMAD1 interactor. PAWS1 forms a complex with SMAD1 in a SMAD4-independent manner, and BMP signalling induces the phosphorylation of PAWS1 through BMPR1A. The phosphorylation of PAWS1 in response to BMP is essential for activation of the SMAD4-independent BMP target genes NEDD9 and ASNS. Our findings identify PAWS1 as the first non-SMAD substrate for type I BMP receptor kinases and as a novel player in the BMP pathway. We also demonstrate that PAWS1 regulates the expression of several non-BMP target genes, suggesting roles for PAWS1 beyond the BMP pathway

    L’appel de la forêt : création d’un stage au choix officiel de médecine en milieu sauvage pour les étudiants au pré-externat d’une université canadienne

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    Implication Statement Wilderness medicine education is interesting to medical students, yet not widely implemented in Canadian medical curricula. We describe a curriculum for a pre-clerkship wilderness medicine elective at a Canadian medical school. Our study reports increased student awareness of career opportunities in wilderness medicine after elective completion, and interest in hands-on learning for wilderness medicine topics. Medical schools may benefit from incorporating feedback from our elective towards a successful wilderness medicine curriculum in their own programs.Énoncé des implications de la recherche La médecine en milieu sauvage est un domaine que les étudiants trouvent intéressant, mais dont l’enseignement est peu répandu dans les programmes d’études médicales au Canada. Nous décrivons le contenu d’un stage au choix de médecine en milieu sauvage offert au pré-externat dans une faculté de médecine canadienne. Notre étude montre qu’à la suite du stage, les étudiants sont mieux informés des possibilités de carrière en médecine en milieu sauvage et qu’ils manifestent un intérêt pour l’apprentissage pratique dans ce domaine médical. Les commentaires recueillis sur notre stage peuvent être utiles à d’autres facultés souhaitant introduire une formation en médecine en milieu sauvage dans leur programme

    The antibacterial efficacy of far-UVC light : a combined-method study exploring the effects of experimental and bacterial variables on dose-response

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    Far-ultraviolet C light, with a wavelength of 200–230 nm, has demonstrated broad-spectrum germicidal efficacy. However, due to increased interest in its use as an alternative antimicrobial, further knowledge about its fundamental bactericidal efficacy is required. This study had two objectives. Firstly, it investigated experimentally the Far-UVC dose–response of common bacteria suspended at various cell densities in transparent buffer, ensuring no influence from photosensitive suspending media. Increasing doses of Far-UVC were delivered to Enterococcus faecium, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus in PBS at 101, 102, 103, 105 and 107 CFU·mL−1, with surviving colony-forming units enumerated (n ≥ 3). Secondly, through a systematised literature review, this work sought to explore the impact of genus/species, Gram type, cell form, cell density and irradiance on dose–response. The screening of 483 publications was performed with 25 included in the study. Data for 30 species were collated, analysed and compared with the experimental results. Overall, Gram-positive species showed greater resilience to Far-UVC than Gram-negative; some inter-species and inter-genera differences in resilience were identified; endospores were more resilient than vegetative cells; the results suggested that inactivation efficiency may decrease as cell density increases; and no significant correlation was identified between irradiance and bactericidal dose effect. In conclusion, this study has shown Far-UVC light to be an effective decontamination tool against a vast range of bacterial vegetative cells and endospores

    Crummer SunTrust Portfolio Recommendations: Crummer Investment Management [2016]

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    The most notable aspect of our strategy is an increase in bond holdings to 18% — the top of the range permitted by our investment policy statement. This defensive position assumes bonds will be low risk in a year of gently rising interest rates and because we see little upside in the stock market. For our tactical allocation, we added sector ETFs to each of our sectors to ensure diversification within sectors and limited the individual names to three per sector, allowing for more selectivity and in-depth research. We have tilted the portfolio towards consumer discretionary, consumer staples and telecommunications, last year’s best performing sectors, because they are favored in less than robust economies

    Accessing mole-scanning through community pharmacy; a pilot service in collaboration with dermatology specialists

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    Early identification and treatment of malignant melanoma is crucial to prevent mortality. The aim of this work was to describe the uptake, profile of users and service outcomes of a mole scanning service in the community pharmacy setting in the UK. In addition, health care costs saved from the perspective of general practice were estimated. The service allowed patients to have concerning skin lesions scanned with a dermatoscopy device which were analyzed remotely by clinical dermatology specialists in order to provide recommendations for the patient. Patients were followed up to ascertain the clinical outcome. Data were analyzed for 6,355 patients and 9,881 scans across 50 community pharmacies. The majority of the scans required no further follow-up (n=8763, 88.7%). Diagnosis was confirmed for 70.4% (n=757/1,118) of scans where patients were recommended to seek further medical attention. Of these, 44.3% were ultimately defined as normal (n=335) and 6.2% as malignant melanoma (n=47/757). An estimated 0.7% of scans taken as part of the service led to a confirmed diagnosis of malignant melanoma. This service evaluation has shown that a mole scanning service available within community pharmacies is effective at triaging patients and ultimately playing a part in identifying diagnoses of malignant melanoma

    Application of pharmacogenomics and bioinformatics to exemplify the utility of human <i>ex vivo</i> organoculture models in the field of precision medicine

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    Here we describe a collaboration between industry, the National Health Service (NHS) and academia that sought to demonstrate how early understanding of both pharmacology and genomics can improve strategies for the development of precision medicines. Diseased tissue ethically acquired from patients suffering from chronic obstructive pulmonary disease (COPD), was used to investigate inter-patient variability in drug efficacy using ex vivo organocultures of fresh lung tissue as the test system. The reduction in inflammatory cytokines in the presence of various test drugs was used as the measure of drug efficacy and the individual patient responses were then matched against genotype and microRNA profiles in an attempt to identify unique predictors of drug responsiveness. Our findings suggest that genetic variation in CYP2E1 and SMAD3 genes may partly explain the observed variation in drug response
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