524 research outputs found

    Transition in Suffolk:A Good Life for Eight Young People in Suffolk

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    Solvent induced swelling of membranes - measurements and influence in nanofiltration

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    This paper describes improvements to an apparatus for in-situ determinations of swelling where a linear inductive probe and electronic column gauge with an overall resolution of 0.1 μm was used for measurements of seven variants of polyacrylonitrile (PAN)/polydimethylsiloxane (PDMS) composite nanofiltration membranes in a range of alkane, aromatic and alcohol solvents. The unswollen membranes incorporated PDMS layers between 1 and 10 μm nominal thickness and were manufactured with a radiation and/or thermal crosslinking step. The tested membranes exhibited a range of swelling dependent on the degree of crosslinking, the initial PDMS layer thickness and the type of solvent. With no applied pressure the PDMS layer on some radiation crosslinked membranes swelled as much as ~170% of the initial thickness whilst other membranes were restricted to a maximum swelling of ~80%. When a pressure up to 2000 kPa was applied to a membrane then swelling could be reduced to ~20% of the value obtained at zero applied pressure. By vertically stacking up to 3 membrane samples it was possible to determine the swelling of PDMS layers as thin as 1 μm, although higher imposed pressures rendered some results unreliable as the measurement resolution of the apparatus was approached. The results of the swelling experiments are contrasted with crossflow nanofiltration performance in terms of solvent flux and solute rejection

    Cold Creep of Titanium: Analysis of stress relaxation using synchrotron diffraction and crystal plasticity simulations

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    There is a long standing technological problem in which a stress dwell during cyclic loading at room temperature in Ti causes a significant fatigue life reduction. It is thought that localised time dependent plasticity in soft grains oriented for easy plastic slip leads to load shedding and an increase in stress within a neighbouring hard grain poorly oriented for easy slip. Quantifying this time dependent plasticity process is key to successfully predicting the complex cold dwell fatigue problem. This work uses a novel approach of in situ synchrotron X-ray diffraction during stress relaxation tests, to quantify the time dependent plasticity. Measured lattice strains from multiple lattice families (21 diffraction rings) were compared with simulated lattice strains from crystal plasticity finite element (CPFE) simulations. The prism slip parameters were found to show stronger strain rate sensitivity compared to basal slip, and this has a significant effect on stress redistribution to hard grain orientations during cold creep

    Health Literacy, Medication Adherence, and Patient Satisfaction in Community Pharmacy

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    Background: Health literacy is defined as the ability to read, understand, and act on health information; almost half of adults have inadequate health literacy. Since inadequate health literacy is often followed by many negative outcomes, such as poor medication adherence, it is important to address health literacy, in order to rectify the low levels and improve outcomes. Patients see pharmacists regularly, and therefore, the pharmacist is crucial In improving medication adherence. If health literacy is a barrier to medication adherence, the community pharmacist should be able to provide health literacy-appropriate counseling to improve medication adherence. Objectives: To determine if pharmacists\u27 perception of patient health literacy and actual patient health literacy align, to assess the relationship between health literacy and medication adherence In patients who visit independent community pharmacies, to evaluate patients\u27 satisfaction with their pharmacists\u27 patient counseling, and to determine the pharmacists\u27 willingness to improve their communication technique with their patients according to their health literacy. Methods: Independent pharmacies were selected from the Cedarvlle network. Patients will complete Instruments to assess health literacy (Newest Vital Signs®), medication adherence (8-item Morisky Medication Adherence Scale©), and patient satisfaction with counseling (Likert-type questions derived from the literature). The patient satisfaction items will be peer-reviewed before finalizing the version given to the patients. Patients will consist of those at least 18 years of age, who speak English, and are obtaining a refill for a chronic condition. Results In Progress: Thus far, the selection process of pharmacies is being conducted, as well as securing the health literacy test, the medication adherence test, and formulating questions for patient satisfaction. Completion is anticipated by the end of spring 2014

    An in-situ synchrotron diffraction study of stress relaxation in titanium:Effect of temperature and oxygen on cold dwell fatigue

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    There is a long-standing technological problem in which a stress dwell during cyclic loading at room temperature in Ti causes a drastic fatigue life reduction. To better understand the material characteristics that control or exacerbate this behaviour, evaluation of the time dependent plasticity of the main prismatic and basal slip systems is critical. Incorporating the influence of operating temperatures and common alloying elements on cold dwell fatigue will be beneficial for future alloy design to address this problem. In this work, characterisation of the time dependent plastic behaviour of two commercially pure titanium samples (grade 1 and grade 4) with different oxygen content at 4 different temperatures (room temperature, 75 , 145 and 250 ) was performed during stress relaxation using synchrotron X-ray diffraction. Key parameters that govern the dislocation motion were determined for the major prismatic and basal slip systems as a function of temperature and oxygen content by calibrating a crystal plasticity finite element model with the measured lattice strain relaxation responses. From the temperatures assessed, 75 was found to be the worst-case scenario, where the macroscopic plastic strain accumulation was significant during a relaxation cycle due to the greatest activity of both prism and basal slip systems. As the temperature increases, the contribution of thermal energy becomes greater than mechanical energy for dislocation glide. Oxygen was found to have a stronger strengthening effect on prism slip over basal slip, through a significant change in their respective critical resolved shear stresses. This effect becomes more significant in high oxygen content commercially pure Ti

    Polyfunctional T cell responses in children in early stages of chronic Trypanosoma cruzi infection contrast with monofunctional responses of long-term infected adults

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    Background: Adults with chronic Trypanosoma cruzi exhibit a poorly functional T cell compartment, characterized by monofunctional (IFN-γ-only secreting) parasite-specific T cells and increased levels of terminally differentiated T cells. It is possible that persistent infection and/or sustained exposure to parasites antigens may lead to a progressive loss of function of the immune T cells. Methodology/Principal Findings: To test this hypothesis, the quality and magnitude of T. cruzi-specific T cell responses were evaluated in T. cruzi-infected children and compared with long-term T. cruzi-infected adults with no evidence of heart failure. The phenotype of CD4+ T cells was also assessed in T. cruzi-infected children and uninfected controls. Simultaneous secretion of IFN-γ and IL-2 measured by ELISPOT assays in response to T. cruzi antigens was prevalent among T. cruzi-infected children. Flow cytometric analysis of co-expression profiles of CD4+ T cells with the ability to produce IFN-γ, TNF-α, or to express the co-stimulatory molecule CD154 in response to T. cruzi showed polyfunctional T cell responses in most T. cruzi-infected children. Monofunctional T cell responses and an absence of CD4+TNF-α+-secreting T cells were observed in T. cruzi-infected adults. A relatively high degree of activation and differentiation of CD4+ T cells was evident in T. cruzi-infected children. Conclusions/Significance: Our observations are compatible with our initial hypothesis that persistent T. cruzi infection promotes eventual exhaustion of immune system, which might contribute to disease progression in long-term infected subjects.Fil: Albareda, María Cecilia. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud. Instituto Nacional de Parasitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón"; ArgentinaFil: de Rissio, Ana María. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud. Instituto Nacional de Parasitología; ArgentinaFil: Tomas, Gonzalo. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud. Instituto Nacional de Parasitología; ArgentinaFil: Serjan, Alicia. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos "Juan A. Fernández"; ArgentinaFil: Alvarez, María Gabriela. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón"; ArgentinaFil: Viotti, Rodolfo Jorge. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón"; ArgentinaFil: Fichera, Laura Edith. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud. Instituto Nacional de Parasitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Esteva, Mónica Inés. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud. Instituto Nacional de Parasitología; ArgentinaFil: Potente, Daniel Fernando. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón"; ArgentinaFil: Armenti, Alejandro. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón"; ArgentinaFil: Tarleton, Rick L.. University of Georgia; Estados UnidosFil: Laucella, Susana Adriana. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud. Instituto Nacional de Parasitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

    Feasibility, drug safety, and effectiveness of etiological treatment programs for Chagas disease in Honduras, Guatemala, and Bolivia: 10-year experience of Médecins Sans Frontières

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    BACKGROUND: Chagas disease (American trypanosomiasis) is a zoonotic or anthropozoonotic disease caused by the parasite Trypanosoma cruzi. Predominantly affecting populations in poor areas of Latin America, medical care for this neglected disease is often lacking. Médecins Sans Frontières/Doctors Without Borders (MSF) has provided diagnostic and treatment services for Chagas disease since 1999. This report describes 10 years of field experience in four MSF programs in Honduras, Guatemala, and Bolivia, focusing on feasibility protocols, safety of drug therapy, and treatment effectiveness. METHODOLOGY: From 1999 to 2008, MSF provided free diagnosis, etiological treatment, and follow-up care for patients <18 years of age seropositive for T. cruzi in Yoro, Honduras (1999-2002); Olopa, Guatemala (2003-2006); Entre Ríos, Bolivia (2002-2006); and Sucre, Bolivia (2005-2008). Essential program components guaranteeing feasibility of implementation were information, education, and communication (IEC) at the community and family level; vector control; health staff training; screening and diagnosis; treatment and compliance, including family-based strategies for early detection of adverse events; and logistics. Chagas disease diagnosis was confirmed by testing blood samples using two different diagnostic tests. T. cruzi-positive patients were treated with benznidazole as first-line treatment, with appropriate counseling, consent, and active participation from parents or guardians for daily administration of the drug, early detection of adverse events, and treatment withdrawal, when necessary. Weekly follow-up was conducted, with adverse events recorded to assess drug safety. Evaluations of serological conversion were carried out to measure treatment effectiveness. Vector control, entomological surveillance, and health education activities were carried out in all projects with close interaction with national and regional programs. RESULTS: Total numbers of children and adolescents tested for T. cruzi in Yoro, Olopa, Entre Ríos, and Sucre were 24,471, 8,927, 7,613, and 19,400, respectively. Of these, 232 (0.9%), 124 (1.4%), 1,475 (19.4%), and 1,145 (5.9%) patients, respectively, were diagnosed as seropositive. Patients were treated with benznidazole, and early findings of seroconversion varied widely between the Central and South American programs: 87.1% and 58.1% at 18 months post-treatment in Yoro and Olopa, respectively; 5.4% by up to 60 months in Entre Ríos; and 0% at an average of 18 months in Sucre. Benznidazole-related adverse events were observed in 50.2% and 50.8% of all patients treated in Yoro and Olopa, respectively, and 25.6% and 37.9% of patients in Entre Ríos and Sucre, respectively. Most adverse events were mild and manageable. No deaths occurred in the treatment population. CONCLUSIONS: These results demonstrate the feasibility of implementing Chagas disease diagnosis and treatment programs in resource-limited settings, including remote rural areas, while addressing the limitations associated with drug-related adverse events. The variability in apparent treatment effectiveness may reflect differences in patient and parasite populations, and illustrates the limitations of current treatments and measures of efficacy. New treatments with improved safety profiles, pediatric formulations of existing and new drugs, and a faster, reliable test of cure are all urgently needed

    Kink pair production and dislocation motion

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    The motion of extended defects called dislocations controls the mechanical properties of crystalline materials such as strength and ductility. Under moderate applied loads, this motion proceeds via the thermal nucleation of kink pairs. The nucleation rate is known to be a highly nonlinear function of the applied load, and its calculation has long been a theoretical challenge. In this article, a stochastic path integral approach is used to derive a simple, general, and exact formula for the rate. The predictions are in excellent agreement with experimental and computational investigations, and unambiguously explain the origin of the observed extreme nonlinearity. The results can also be applied to other systems modelled by an elastic string interacting with a periodic potential, such as Josephson junctions in superconductors
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