501 research outputs found

    Neutron interferometric measurement of the scattering length difference between the triplet and singlet states of n-3^3He

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    We report a determination of the n-3^3He scattering length difference Δb′=b1′−b0′=\Delta b^{\prime} = b_{1}^{\prime}-b_{0}^{\prime} = (−5.411-5.411 ±\pm 0.0310.031 (statistical) ±\pm 0.0390.039 (systematic)) fm between the triplet and singlet states using a neutron interferometer. This revises our previous result Δb′=\Delta b^{\prime} = (-5.610 ±\pm 0.0270.027 (statistical) ±\pm 0.0320.032 (systematic) fm obtained using the same technique in 2008. This revision is due to a re-analysis of the 2008 experiment that includes a more robust treatment of the phase shift caused by magnetic field gradients near the 3^3He cell. Furthermore, we more than doubled our original data set from 2008 by acquiring six months of additional data in 2013. Both the new data set and a re-analysis of the older data are in good agreement. Scattering lengths of low Z isotopes are valued for use in few-body nuclear effective field theories, provide important tests of modern nuclear potential models and in the case of 3^3He aid in the interpretation of neutron scattering from quantum liquids. The difference Δb′\Delta b^{\prime} was determined by measuring the relative phase shift between two incident neutron polarizations caused by the spin-dependent interaction with a polarized 3^3He target. The target 3^3He gas was sealed inside a small, flat windowed glass cell that was placed in one beam path of the interferometer. The relaxation of 3^3He polarization was monitored continuously with neutron transmission measurements. The neutron polarization and spin flipper efficiency were determined separately using 3^3He analyzers and two different polarimetry analysis methods. A summary of the measured scattering lengths for n-3^3He with a comparison to nucleon interaction models is given

    Drosophila modifier screens to identify novel neuropsychiatric drugs including aminergic agents for the possible treatment of Parkinson's disease and depression.

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    Small molecules that increase the presynaptic function of aminergic cells may provide neuroprotection in Parkinson's disease (PD) as well as treatments for attention deficit hyperactivity disorder (ADHD) and depression. Model genetic organisms such as Drosophila melanogaster may enhance the detection of new drugs via modifier or 'enhancer/suppressor' screens, but this technique has not been applied to processes relevant to psychiatry. To identify new aminergic drugs in vivo, we used a mutation in the Drosophila vesicular monoamine transporter (dVMAT) as a sensitized genetic background and performed a suppressor screen. We fed dVMAT mutant larvae ∼ 1000 known drugs and quantitated rescue (suppression) of an amine-dependent locomotor deficit in the larva. To determine which drugs might specifically potentiate neurotransmitter release, we performed an additional secondary screen for drugs that require presynaptic amine storage to rescue larval locomotion. Using additional larval locomotion and adult fertility assays, we validated that at least one compound previously used clinically as an antineoplastic agent potentiates the presynaptic function of aminergic circuits. We suggest that structurally similar agents might be used to development treatments for PD, depression and ADHD, and that modifier screens in Drosophila provide a new strategy to screen for neuropsychiatric drugs. More generally, our findings demonstrate the power of physiologically based screens for identifying bioactive agents for select neurotransmitter systems

    Decoupling of a Neutron Interferometer from Temperature Gradients

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    Neutron interferometry enables precision measurements that are typically operated within elaborate, multi-layered facilities which provide substantial shielding from environmental noise. These facilities are necessary to maintain the coherence requirements in a perfect crystal neutron interferometer which is extremely sensitive to local environmental conditions such as temperature gradients across the interferometer, external vibrations, and acoustic waves. The ease of operation and breadth of applications of perfect crystal neutron interferometry would greatly benefit from a mode of operation which relaxes these stringent isolation requirements. Here, the INDEX Collaboration and National Institute of Standards and Technology demonstrates the functionality of a neutron interferometer in vacuum and characterize the use of a compact vacuum chamber enclosure as a means to isolate the interferometer from spatial temperature gradients and time-dependent temperature fluctuations. The vacuum chamber is found to have no depreciable effect on the performance of the interferometer (contrast) while improving system stability, thereby showing that it is feasible to replace large temperature isolation and control systems with a compact vacuum enclosure for perfect crystal neutron interferometry

    Novel bioactive tetracycline-containing electrospun polymer fibers as a potential antibacterial dental implant coating

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    The purpose of this investigation was to determine the ability of tetracycline-containing fibers to inhibit biofilm formation of peri-implantitis-associated pathogens [i.e., Porphyromonas gingivalis (Pg), Fusobacterium nucleatum (Fn), Prevotella intermedia (Pi), and Aggregatibacter actinomycetemcomitans (Aa)]. Tetracycline hydrochloride (TCH) was added to a poly(DL-lactide) [PLA], poly(ε-caprolactone) [PCL], and gelatin [GEL] polymer blend solution at distinct concentrations to obtain the following fibers: PLA:PCL/GEL (TCH-free, control), PLA:PCL/GEL + 5 % TCH, PLA:PCL/GEL + 10 % TCH, and PLA:PCL/GEL + 25 % TCH. The inhibitory effect of TCH-containing fibers on biofilm formation was assessed by colony-forming units (CFU/mL). Qualitative analysis of biofilm inhibition was done via scanning electron microscopy (SEM). Statistical significance was reported at p < 0.05. Complete inhibition of biofilm formation on the fibers was observed in groups containing TCH at 10 and 25 wt%. Fibers containing TCH at 5 wt% demonstrated complete inhibition of Aa biofilm. Even though a marked reduction in CFU/mL was observed with an increase in TCH concentration, Pi proved to be the most resilient microorganism. SEM images revealed the absence of or a notable decrease in bacterial biofilm on the TCH-containing nanofibers. Collectively, our data suggest that tetracycline-containing fibers hold great potential as an antibacterial dental implant coating

    Factors influencing early and late readmissions in Australian hospitalised patients and investigating role of admission nutrition status as a predictor of hospital readmissions: a cohort study

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    Objectives: Limited studies have identified predictors of early and late hospital readmissions in Australian healthcare settings. Some of these predictors may be modifiable through targeted interventions. A recent study has identified malnutrition as a predictor of readmissions in older patients but this has not been verified in a larger population. This study investigated what predictors are associated with early and late readmissions and determined whether nutrition status during index hospitalisation can be used as a modifiable predictor of unplanned hospital readmissions. Design: A retrospective cohort study. Setting: Two tertiary-level hospitals in Australia. Participants: All medical admissions ≥18 years over a period of 1 year. Outcomes: Primary objective was to determine predictors of early (0–7 days) and late (8–180 days) readmissions. Secondary objective was to determine whether nutrition status as determined by malnutrition universal screening tool (MUST) can be used to predict readmissions. Results: There were 11 750 (44.8%) readmissions within 6 months, with 2897 (11%) early and 8853 (33.8%) late readmissions. MUST was completed in 16.2% patients and prevalence of malnutrition during index admission was 31%. Malnourished patients had a higher risk of both early (OR 1.39, 95% CI 1.12 to 1.73) and late readmissions (OR 1.23, 95% CI 1.06 to 128). Weekend discharges were less likely to be associated with both early (OR 0.81, 95% CI 0.74 to 0.91) and late readmissions (OR 0.91, 95% CI 0.84 to 0.97). Indigenous Australians had a higher risk of early readmissions while those living alone had a higher risk of late readmissions. Patients ≥80 years had a lower risk of early readmissions while admission to intensive care unit was associated with a lower risk of late readmissions. Conclusions: Malnutrition is a strong predictor of unplanned readmissions while weekend discharges are less likely to be associated with readmissions. Targeted nutrition intervention may prevent unplanned hospital readmissions.Yogesh Sharma, Michelle Miller, Billingsley Kaambwa, Rashmi Shahi, Paul Hakendorf, Chris Horwood, Campbell Thompso

    Anxiety and depression among people living in quarantine centers during COVID-19 pandemic: a mixed method study from western Nepal

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    Background In response to the COVID-19 pandemic, incoming travelers were quarantined at specific centers in Nepal and major checkpoints in Nepal-India border. Nepal adopted a generic public health approaches to control and quarantine returnee migrants, with little attention towards the quality of quarantine facilities and its aftermath, such as the poor mental health of the returnee migrants. The main objective of this study was to explore the status of anxiety and depression, and factors affecting them among returnee migrants living in institutional quarantine centers of western Nepal. Methods A mixed method approach in this study included a quantitative survey and in-depth interviews (IDIs) among respondents in quarantine centers of Karnali province between 21st April and 15th May 2020. Survey questionnaire utilized Beck Depression Inventory (BDI) and Beck Anxiety Inventory (BAI) tools, which were administered among 441 quarantined returnee migrants. IDIs were conducted among 12 participants which included a mix of six quarantined migrants and healthcare workers each from the quarantine centres. Descriptive and inferential analyses were conducted on quantitative data; and thematic analysis was utilized for qualitative data. Results Mild depression (9.1%; 40/441) and anxiety (16.1%; 71/441) was common among respondents followed by moderate depression and anxiety {depression (3.4%; 15/441), anxiety (4.1%; 18/441)} and severe depression and anxiety {depression (1.1%; 5/441), anxiety (0.7%; 3/441)}. Anxiety and depression were independent of their socio-demographic characteristics. Perceived fear of contracting COVID-19, severity and death were prominent among the respondents. Respondents experienced stigma and discrimination in addition to being at the risk of disease and possible loss of employment and financial responsibilities. In addition, poor (quality and access to) health services, and poor living condition at the quarantine centres adversely affected respondents’ mental health. Conclusion Depression and anxiety were high among quarantined population and warrants more research. Institutional quarantine centers of Karnali province of Nepal were in poor conditions which adversely impacted mental health of the respondents. Poor resource allocation for health, hygiene and living conditions can be counterproductive to the population quarantined

    What are the main inefficiencies in trial conduct : a survey of UKCRC registered clinical trials units in the UK

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    BACKGROUND: The UK Clinical Research Collaboration (UKCRC) registered Clinical Trials Units (CTUs) Network aims to support high-quality, efficient and sustainable clinical trials research in the UK. To better understand the challenges in efficient trial conduct, and to help prioritise tackling these challenges, we surveyed CTU staff. The aim was to identify important inefficiencies during two key stages of the trial conduct life cycle: (i) from grant award to first participant, (ii) from first participant to reporting of final results. METHODS: Respondents were asked to list their top three inefficiencies from grant award to recruitment of the first participant, and from recruitment of the first participant to publication of results. Free text space allowed respondents to explain why they thought these were important. The survey was constructed using SurveyMonkey and circulated to the 45 registered CTUs in May 2013. Respondents were asked to name their unit and job title, but were otherwise anonymous. Free-text responses were coded into broad categories. RESULTS: There were 43 respondents from 25 CTUs. The top inefficiency between grant award and recruitment of first participant was reported as obtaining research and development (R&D) approvals by 23 respondents (53%), contracts by 22 (51%), and other approvals by 13 (30%). The top inefficiency from recruitment of first participant to publication of results was failure to meet recruitment targets, reported by 19 (44%) respondents. A common comment was that this reflected overoptimistic or inaccurate estimates of recruitment at site. Data management, including case report form design and delays in resolving data queries with sites, was reported as an important inefficiency by 11 (26%) respondents, and preparation and submission for publication by 9 (21%). CONCLUSIONS: Recommendations for improving the efficiency of trial conduct within the CTUs network include: further reducing unnecessary bureaucracy in approvals and contracting; improving training for site staff; realistic recruitment targets and appropriate feasibility; developing training across the network; improving the working relationships between chief investigators and units; encouraging funders to release sufficient funding to allow prompt recruitment of trial staff; and encouraging more research into how to improve the efficiency and quality of trial conduct
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