296 research outputs found

    Director dynamics in liquid-crystal physical gels

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    Nematic liquid-crystal (LC) elastomers and gels have a rubbery polymer network coupled to the nematic director. While LC elastomers show a single, non-hydrodynamic relaxation mode, dynamic light-scattering studies of self-assembled liquid-crystal gels reveal orientational fluctuations that relax over a broad time scale. At short times, the relaxation dynamics exhibit hydrodynamic behavior. In contrast, the relaxation dynamics at long times are non-hydrodynamic, highly anisotropic, and increase in amplitude at small scattering angles. We argue that the slower dynamics arise from coupling between the director and the physically associated network, which prevents director orientational fluctuations from decaying completely at short times. At long enough times the network restructures, allowing the orientational fluctuations to fully decay. Director dynamics in the self-assembled gels are thus quite distinct from those observed in LC elastomers in two respects: they display soft orientational fluctuations at short times, and they exhibit at least two qualitatively distinct relaxation processes

    Investimento social em cuidados de longa duração para idosos: um guia para avaliação de impactos

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    Este recurso é um produto do projeto SPRINT. Descreve os fatores a serem considerados ao avaliar o potencial de investimento social em cuidados de longa duração e descreve os princípios para a criação de um mapa de impacto para os prestadores de cuidados

    Using research to prepare for outbreaks of severe acute respiratory infection

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    Severe acute respiratory infections (SARI) remain one of the leading causes of mortality around the world in all age groups. There is large global variation in epidemiology, clinical management and outcomes, including mortality. We performed a short period observational data collection in critical care units distributed globally during regional peak SARI seasons from 1 January 2016 until 31 August 2017, using standardised data collection tools. Data were collected for 1 week on all admitted patients who met the inclusion criteria for SARI, with follow-up to hospital discharge. Proportions of patients across regions were compared for microbiology, management strategies and outcomes. Regions were divided geographically and economically according to World Bank definitions. Data were collected for 682 patients from 95 hospitals and 23 countries. The overall mortality was 9.5%. Of the patients, 21.7% were children, with case fatality proportions of 1% for those less than 5 years. The highest mortality was in those above 60 years, at 18.6%. Case fatality varied by region: East Asia and Pacific 10.2% (21 of 206), Sub-Saharan Africa 4.3% (8 of 188), South Asia 0% (0 of 35), North America 13.6% (25 of 184), and Europe and Central Asia 14.3% (9 of 63). Mortality in low-income and low-middle-income countries combined was 4% as compared with 14% in high-income countries. Organ dysfunction scores calculated on presentation in 560 patients where full data were available revealed Sequential Organ Failure Assessment (SOFA) scores on presentation were significantly associated with mortality and hospital length of stay. Patients in East Asia and Pacific (48%) and North America (24%) had the highest SOFA scores of >12. Multivariable analysis demonstrated that initial SOFA score and age were independent predictors of hospital survival. There was variability across regions and income groupings for the critical care management and outcomes of SARI. Intensive care unit-specific factors, geography and management features were less reliable than baseline severity for predicting ultimate outcome. These findings may help in planning future outbreak severity assessments, but more globally representative data are required

    A centrality measure for quantifying spread on weighted, directed networks

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    While many centrality measures for complex networks have been proposed, relatively few have been developed specifically for weighted, directed (WD) networks. Here we propose a centrality measure for spread (of information, pathogens, etc.) through WD networks based on the independent cascade model (ICM). While deriving exact results for the ICM requires Monte Carlo simulations, we show that our centrality measure (Viral Centrality) provides excellent approximation to ICM results for networks in which the weighted strength of cycles is not too large. We show this can be quantified with the leading eigenvalue of the weighted adjacency matrix, and we show that Viral Centrality outperforms other common centrality measures in both simulated and empirical WD networks.Comment: 3 figure

    Apolipoprotein L1 gene variants associate with prevalent kidney but not prevalent cardiovascular disease in the Systolic Blood Pressure Intervention Trial.

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    Apolipoprotein L1 gene (APOL1) G1 and G2 coding variants are strongly associated with chronic kidney disease (CKD) in African Americans (AAs). Here APOL1 association was tested with baseline estimated glomerular filtration rate (eGFR), urine albumin:creatinine ratio (UACR), and prevalent cardiovascular disease (CVD) in 2571 AAs from the Systolic Blood Pressure Intervention Trial (SPRINT), a trial assessing effects of systolic blood pressure reduction on renal and CVD outcomes. Logistic regression models that adjusted for potentially important confounders tested for association between APOL1 risk variants and baseline clinical CVD (myocardial infarction, coronary, or carotid artery revascularization) and CKD (eGFR under 60 ml/min per 1.73 m(2) and/or UACR over 30 mg/g). AA SPRINT participants were 45.3% female with a mean (median) age of 64.3 (63) years, mean arterial pressure 100.7 (100) mm Hg, eGFR 76.3 (77.1) ml/min per 1.73 m(2), and UACR 49.9 (9.2) mg/g, and 8.2% had clinical CVD. APOL1 (recessive inheritance) was positively associated with CKD (odds ratio 1.37, 95% confidence interval 1.08-1.73) and log UACR estimated slope (β) 0.33) and negatively associated with eGFR (β -3.58), all significant. APOL1 risk variants were not significantly associated with prevalent CVD (1.02, 0.82-1.27). Thus, SPRINT data show that APOL1 risk variants are associated with mild CKD but not with prevalent CVD in AAs with a UACR under 1000 mg/g

    SPRINT qualitative findings

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    APHCRI Conversations was a regular program of presentations held at the Department of Health to facilitate exchange between APHCRI Network researchers and Department policymakers. Topics are developed jointly with the Department of Health and involve a range of speakers from APHCRI, including CRE invited experts, CRE Chief Investigators and stream project Chief Investigator

    スプリントにおける伸張反射プログラムが陸上競技選手のパフォーマンス向上に及ぼす有用性─異なるトレーニング環境が加速能力に与える影響について─

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    We investigated the effectiveness of stretch reflex programs (SRPs) in 17 male students (mean age: 20.2 ± 0.9 years) who were track and field athletes. The effect of the SRP conditions in improving the 100-m sprint performance was explored. The different training environments were level ground, uphill, and downhill, and the subjects were assigned evenly to an SRP group for each environment and a control group. The students performed their SRPs (rebound jump, slalom jump, single-leg hop (right and left), bounding, and speed bounding) three times a week for 9 weeks. The control group received regular training. The primary findings were as follows:1. Over 0 to 30 m, the SPR groups showed improved pitch and stride under all conditions, with a marked improvement in the downhill training environment group.2. An SRP using a downhill slope of four degrees or less was effective as a training environment to improve sprinting speed in the acceleration period.3. An SRP using an uphill slope was a suitable environment for improving only the pitch in sprinting.4. The improvement in stride between 0 and 30 m in the downhill SRP group likely contributed to increases in both pitch and stride between 30 and 100 m.These results showed that an SRP performed downhill increased pitch and its tradeoff counterpart—stride—effectively between 0 and 30 m and significantly improved sprinting speed over 30 to 100 m. The study therefore demonstrated that downhill is the most appropriate environment for SRP training

    Response to ibudilast treatment according to progressive multiple sclerosis disease phenotype

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    OBJECTIVE: Determine whether a treatment effect of ibudilast on brain atrophy rate differs between participants with primary (PPMS) and secondary (SPMS) progressive multiple sclerosis. BACKGROUND: Progressive forms of MS are both associated with continuous disability progression. Whether PPMS and SPMS differ in treatment response remains unknown. DESIGN/METHODS: SPRINT-MS was a randomized, placebo-controlled 96-week phase 2 trial in both PPMS (n = 134) and SPMS (n = 121) patients. The effect of PPMS and SPMS phenotype on the rate of change of brain atrophy measured by brain parenchymal fraction (BPF) was examined by fitting a three-way interaction linear-mixed model. Adjustment for differences in baseline demographics, disease measures, and brain size was explored. RESULTS: Analysis showed that there was a three-way interaction between the time, treatment effect, and disease phenotype (P \u3c 0.06). After further inspection, the overall treatment effect was primarily driven by patients with PPMS (P \u3c 0.01), and not by patients with SPMS (P = 0.97). This difference may have been due to faster brain atrophy progression seen in the PPMS placebo group compared to SPMS placebo (P \u3c 0.02). Although backward selection (P \u3c 0.05) retained age, T2 lesion volume, RNFL, and longitudinal diffusivity as significant baseline covariates in the linear-mixed model, the adjusted overall treatment effect was still driven by PPMS (P \u3c 0.01). INTERPRETATION: The previously reported overall treatment effect of ibudilast on worsening of brain atrophy in progressive MS appears to be driven by patients with PPMS that may be, in part, because of the faster atrophy progression rates seen in the placebo-treated group
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