4,916 research outputs found

    Simultaneous polymerization and molding of Pyrrone polymers

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    Simultaneous polymerization and hot pressing of Pyrrone polymer

    Exploring the Variable Sky with LINEAR. I. Photometric Recalibration with the Sloan Digital Sky Survey

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    We describe photometric recalibration of data obtained by the asteroid survey LINEAR. Although LINEAR was designed for astrometric discovery of moving objects, the data set described here contains over 5 billion photometric measurements for about 25 million objects, mostly stars. We use Sloan Digital Sky Survey (SDSS) data from the overlapping ~10,000 deg^2 of sky to recalibrate LINEAR photometry and achieve errors of 0.03 mag for sources not limited by photon statistics with errors of 0.2 mag at r ~ 18. With its 200 observations per object on average, LINEAR data provide time domain information for the brightest four magnitudes of the SDSS survey. At the same time, LINEAR extends the deepest similar wide-area variability survey, the Northern Sky Variability Survey, by 3 mag. We briefly discuss the properties of about 7000 visually confirmed periodic variables, dominated by roughly equal fractions of RR Lyrae stars and eclipsing binary stars, and analyze their distribution in optical and infrared color-color diagrams. The LINEAR data set is publicly available from the SkyDOT Web site

    Gait dynamics in mouse models of Parkinson's disease and Huntington's disease

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    BACKGROUND: Gait is impaired in patients with Parkinson's disease (PD) and Huntington's disease (HD), but gait dynamics in mouse models of PD and HD have not been described. Here we quantified temporal and spatial indices of gait dynamics in a mouse model of PD and a mouse model of HD. METHODS: Gait indices were obtained in C57BL/6J mice treated with the dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 30 mg/kg/day for 3 days) for PD, the mitochondrial toxin 3-nitropropionic acid (3NP, 75 mg/kg cumulative dose) for HD, or saline. We applied ventral plane videography to generate digital paw prints from which indices of gait and gait variability were determined. Mice walked on a transparent treadmill belt at a speed of 34 cm/s after treatments. RESULTS: Stride length was significantly shorter in MPTP-treated mice (6.6 ± 0.1 cm vs. 7.1 ± 0.1 cm, P < 0.05) and stride frequency was significantly increased (5.4 ± 0.1 Hz vs. 5.0 ± 0.1 Hz, P < 0.05) after 3 administrations of MPTP, compared to saline-treated mice. The inability of some mice treated with 3NP to exhibit coordinated gait was due to hind limb failure while forelimb gait dynamics remained intact. Stride-to-stride variability was significantly increased in MPTP-treated and 3NP-treated mice compared to saline-treated mice. To determine if gait disturbances due to MPTP and 3NP, drugs affecting the basal ganglia, were comparable to gait disturbances associated with motor neuron diseases, we also studied gait dynamics in a mouse model of amyotrophic lateral sclerosis (ALS). Gait variability was not increased in the SOD1 G93A transgenic model of ALS compared to wild-type control mice. CONCLUSION: The distinct characteristics of gait and gait variability in the MPTP model of Parkinson's disease and the 3NP model of Huntington's disease may reflect impairment of specific neural pathways involved

    EMG Analysis of Neural Activation Patterns of the Gluteal Muscle Complex

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    Gluteal amnesia is described as a condition in which the neural recruitment patterns of the gluteal muscle complex are insufficient to activate muscle fibers, causing the hamstring and lower back muscles to take up the physical demand. Symptoms due to insufficient gluteal muscle activation include tight hamstrings post-exercise, anterior pelvic tilt, and knee valgus during squat or lunge performance. This could lead to compensation injuries of the lumbar, knee, and ankle joints. Many physical therapy rehabilitation programs of the lower back and lower extremity incorporate gluteal exercises which could potentially treat this condition and prevent compensation injuries. PURPOSE: To identify and test a person experiencing symptoms of gluteal amnesia to determine gluteal muscle activation before and after a therapy program designed to enhance muscle recruitment and function. METHODS: A 74-year-old male experiencing symptoms of unilateral gluteal amnesia was recruited for this case-study. Electromyographic (EMG) analysis of the gluteal muscle complex was recorded while the subject performed movements typically associated with gluteal muscle complex activation. Both the affected and unaffected side were analyzed while the subject performed movements, as well as submaximal and maximal voluntary isometric contractions (MVIC). After baseline testing, a daily, 3-week progressive resistance rehabilitation program consisting of exercises utilizing the gluteal muscle complex was completed. After completion of the rehabilitation program, EMG analysis of the affected and unaffected sides was performed as during the baseline measures. Integrated EMG signals of gluteal activation were compared between pre- and post-tests. Baseline EMG was considered to be 100% of muscle activation. The post-rehabilitation EMG during MVIC was a percentage of the maximal effort output. MVIC of the submaximal tests were obtained by comparing the quadruped hip extension and single leg glute bridge exercises to the standing gluteal squeeze, and the quadruped hip abduction and clam shell exercises to the side lying hip abduction. RESULTS: Increased gluteal complex activation post-rehabilitation was evident in both the affected and unaffected limbs. Specifically, the largest increases of the left and ride side were seen through the quadruped hip extension (18.7%, 52.4%) and quadruped hip abduction (54.1%, 98.8%) exercises, respectively. The left limb presenting with gluteal amnesia symptoms consistently gave lower output values. CONCLUSION: In this case-study, increased EMG activity in the affected muscles, progressive increases in resistance during daily rehabilitation and anecdotal improvements in movement patterns were observed. Based on the results of this case-study, treatment for conditions such as gluteal amnesia and other disorders of ineffective motor unit recruitment should include targeted rehabilitation exercises designed to isolate the affected musculature

    Controlled temperature chain for vaccination in low- and middle-income countries: a realist evidence synthesis

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    Objective To evaluate the evidence describing how the controlled temperature chain approach for vaccination could lead to improved equitable immunization coverage in low-and middle-income countries. Methods We created a theory of change construct from the Controlled temperature chain: strategic roadmap for priority vaccines 2017–2020, containing four domains: (i) uptake and demand for the approach; (ii) compliance and safe use of the approach; (iii) programmatic efficiency gains from the approach; and (iv) improved equitable immunization coverage. To verify and improve the theory of change, we applied a realist review method to analyse published descriptions of controlled temperature chain or closely related experiences. Findings We evaluated 34 articles, describing 22 unique controlled temperature chain or closely related experiences across four World Health Organization regions. We identified a strong demand for this approach among service delivery providers; however, generating an equal level of demand among policy-makers requires greater evidence on economic benefits and on vaccination coverage gains, and use case definitions. Consistent evidence supported safety of the approach when integrated into special vaccination programmes. Feasible training and supervision supported providers in complying with protocols. Time-savings were the main evidence for efficiency gains, while cost-saving data were minimal. Improved equitable coverage was reported where vaccine storage beyond the cold chain enabled access to hard-to-reach populations. No evidence indicated an inferior vaccine effectiveness nor increased adverse event rates for vaccines delivered under the approach. Conclusion Synthesized evidence broadly supported the initial theory of change. Addressing evidence gaps on economic benefits and coverage gains may increase future uptake

    Feasibility trial of a psychoeducational intervention for parents with personality difficulties: the Helping Families Programme

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    The Helping Families Programme is a psychoeducational parenting intervention that aims to improve outcomes and engagement for parents affected by clinically significant personality difficulties. This is achieved by working collaboratively with parents to explore ways in which their emotional and relational difficulties impact on parenting and child functioning, and to identify meaningful and realistic goals for change. The intervention is delivered via one-to-one sessions at weekly intervals over a period of 16 weeks. This protocol describes a two arm parallel RCT in which consenting parents are randomly allocated in a 1:1 ratio to either the Helping Families Programme plus the usual services that the parent may be receiving from their mental health and/or social care providers, or to standard care (usual services plus a brief parenting advice session). The primary clinical outcome will be child behaviour. Secondary clinical outcomes will be child and parental mental health, parenting satisfaction, parenting behaviour and therapeutic alliance. Health economic measures will be collected on quality of life and service use. Outcome measures will be collected at the initial assessment stage, after the intervention is completed and at 6-month follow-up by research staff blind to group allocation. Trial feasibility will be assessed using rates of trial participation at the three time points and intervention uptake, attendance and retention. A parallel process evaluation will use qualitative interviews to ascertain key-workers’ and parent participants' experiences of intervention delivery and trial participation. The results of this feasibility study will determine the appropriateness of proceeding to a full-scale trial

    Predictors and outcomes of crossover to surgery from physical therapy for meniscal tear and osteoarthritis a randomized trial comparing physical therapy and surgery

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    BACKGROUND: Arthroscopic partial meniscectomy (APM) combined with physical therapy (PT) have yielded pain relief similar to that provided by PT alone in randomized trials of subjects with a degenerative meniscal tear. However, many patients randomized to PT received APM before assessment of the primary outcome. We sought to identify factors associated with crossing over to APM and to compare pain relief between patients who had crossed over to APM and those who had been randomized to APM. METHODS: We used data from the MeTeOR (Meniscal Tear in Osteoarthritis Research) Trial of APM with PT versus PT alone in subjects ≥45 years old who had mild-to-moderate osteoarthritis and a degenerative meniscal tear. We assessed independent predictors of crossover to APM among those randomized to PT. We also compared pain relief at 6 months among those randomized to PT who crossed over to APM, those who did not cross over, and those originally randomized to APM. RESULTS: One hundred and sixty-four subjects were randomized to and received APM and 177 were randomized to PT, of whom 48 (27%) crossed over to receive APM in the first 140 days after randomization. In multivariate analyses, factors associated with a higher likelihood of crossing over to APM among those who had originally been randomized to PT included a baseline Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Pain Score of ≥40 (risk ratio [RR] = 1.99; 95% confidence interval [CI] = 1.00, 3.93) and symptom duration of <1 year (RR = 1.74; 95% CI = 0.98, 3.08). Eighty-one percent of subjects who crossed over to APM and 82% of those randomized to APM had an improvement of ≥10 points in their pain score at 6 months, as did 73% of those who were randomized to and received only PT. CONCLUSIONS: Subjects who crossed over to APM had presented with a shorter symptom duration and greater baseline pain than those who did not cross over from PT. Subjects who crossed over had rates of surgical success similar to those of the patients who had been randomized to surgery. Our findings also suggest that an initial course of rigorous PT prior to APM may not compromise surgical outcome. LEVEL OF EVIDENCE: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence

    Performance Testing of a Photocatalytic Oxidation Module for Spacecraft Cabin Atmosphere Revitalization

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    Photocatalytic oxidation (PCO) is a candidate process technology for use in high volumetric flow rate trace contaminant control applications in sealed environments. The targeted application for PCO as applied to crewed spacecraft life support system architectures is summarized. Technical challenges characteristic of PCO are considered. Performance testing of a breadboard PCO reactor design for mineralizing polar organic compounds in a spacecraft cabin atmosphere is described. Test results are analyzed and compared to results reported in the literature for comparable PCO reactor designs

    Biomass burning aerosol over the Amazon: analysis of aircraft, surface and satellite observations using a global aerosol model

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    Vegetation fires emit large quantities of aerosol into the atmosphere, impacting regional air quality and climate. Previous work has used comparisons of simulated and observed aerosol optical depth (AOD) in regions heavily impacted by fires to suggest that emissions of aerosol particles from fires may be underestimated by a factor of 2–5. Here we use surface, aircraft and satellite observations made over the Amazon during September 2012, along with a global aerosol model to improve understanding of aerosol emissions from vegetation fires. We apply three different satellite-derived fire emission datasets (FINN, GFED, GFAS) in the model. Daily mean aerosol emissions in these datasets vary by up to a factor of 3.7 over the Amazon during this period, highlighting the considerable uncertainty in emissions. We find variable agreement between the model and observed aerosol mass concentrations. The model reproduces observed aerosol concentrations over deforestation fires well in the western Amazon during dry season conditions with FINN or GFED emissions and during dry–wet transition season conditions with GFAS emissions. In contrast, the model underestimates aerosol concentrations over savanna fires in the Cerrado environment east of the Amazon Basin with all three fire emission datasets. The model generally underestimates AOD compared to satellite and ground stations, even when the model reproduces the observed vertical profile of aerosol mass concentration. We suggest it is likely caused by uncertainties in the calculation of AOD, which are as large as ∼90 %, with the largest sensitivities due to uncertainties in water uptake and relative humidity. Overall, we do not find evidence that particulate emissions from fires are systematically underestimated in the Amazon region and we caution against using comparison with AOD to constrain particulate emissions from fires

    Use of small animal PET-CT imaging for in vivo assessment of tendon-to-bone healing: A pilot study.

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    BACKGROUND The availability of non-invasive means to evaluate and monitor tendon-bone healing processes in-vivo is limited. Micro Positron-Emission-Tomography (µPET) using 18F-Fluoride is a minimally invasive imaging modality, with which osteoblast activity and bone turnover can be assessed. The aim of this study was to investigate the use of serial in-vivo µPET/CT scans to evaluate bone turnover along the graft-tunnel interface in a rat ACL (anterior cruciate ligament) reconstruction model. METHODS Unilateral autograft ACL reconstruction was performed in six rats. µPET/CT-scans using 18F-Fluoride were performed 7, 14, 21, and 28 days postoperatively. Standard uptake values (SUV) were calculated for three tunnel regions (intraarticular aperture (IAA), mid-tunnel, and extraarticular aperture (EAA)) of the proximal tibia. Animals were sacrificed at 28 days and evaluated with µCT and histological analysis. RESULTS SUVs in both bone tunnels showed an increased 18F-Fluoride uptake at 7 days when compared to 14, 21, and 28 days. SUVs showed a gradient on the tibial side, with most bone turnover in the IAA and least in the EAA. At 7, 14, 21, and 28 days, there were significantly higher SUV values in the IAA compared to the EAA (p = .01, < .01, < .01, < .01). SUVs positively correlated with new bone volumetric density obtained with μCT (r = 0.449, p = .013). Volumetric density of newly formed bone detected on μCT correlated with osteoblast numbers observed along the tunnels in histological sections (r = 0.452, p < .016). CONCLUSIONS Serial in-vivo µPET/CT-scanning has the potential to provide insight into bone turnover and therefore osteoblastic activity during the healing process. As a result, it allows us to directly measure the effect of interventional strategies in tendon-bone healing
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