371 research outputs found

    Exercise Training to Target Gait Unsteadiness in People with Diabetes

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    Balance impairment and an associated high fall rate in people with diabetes is common, and a huge burden to quality of life and healthcare systems. Causes of impaired balance are commonly attributed to both sensory and motor deficits, which includes impaired muscle strength and function. This study investigated the effects of resistance exercise training on balance control during walking over level ground and on stairs. Ten DM people (age: 62 years, BMI: 29kg/m2, VPT: 9V) and 6 DM people with DPN (age: 59 years, BMI: 27kg/m2, VPT: 31V) performed a 16-week intervention of weekly resistance exercise training to increase ankle and knee extensor muscle strength. Six DM controls did not take part in the intervention (age: 50 years, BMI: 26kg/m2, VPT: 12V). Balance during gait was quantified before and after the intervention, by separation between the body centre-of-mass and centre-of-pressure under the feet during both level and stair walking. Knee and ankle extensor muscle strength was assessed using a dynamometer. The exercise intervention increased strength of ankle plantar flexors (22%) and knee extensors (30%). Despite the increases in lower limb muscle strength produced by the intervention, no improvements in balance were seen post training. However, gait speed did increase by 8%, which previous research has shown to be associated with quality of life. Controls showed no training effects in any variables. Although this exercise intervention had a positive effect on gait by increasing walking speed, there was no effect on the control of balance. Previous research has identified that medio-lateral (side-to-side) balance is impaired in people with DPN. The muscles exercised in the present study mainly control the major sagittal plane (forwards-backwards) movements that occur during gait. Interventions targeting the lateral stabilising muscles of the hip and trunk, may show greater potential efficacy in redressing the balance impairment of this population

    Acute Effects of Vibrating Insoles on Dynamic Balance and Gait Quality in Individuals With Diabetic Peripheral Neuropathy: A Randomized Crossover Study

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    OBJECTIVE This study investigated the effects of vibrating insoles on dynamic balance and gait quality during level and stair walking and explored the influence of vibration type and frequency in individuals with diabetic peripheral neuropathy (DPN). RESEARCH DESIGN AND METHODS Twenty-two men with DPN were assessed for gait quality and postural and dynamic balance during walking and stair negotiation using a motion capture system and force plates across seven vibratory insole conditions (Vcs) versus a control (Ctrl) condition (insole without vibration). Vibration was applied during standing and walking tasks, and 15-min rest-stop periods without vibration were interposed between conditions. Repeated measures test conditions were randomized. The primary outcomes were gait speed and dynamic balance. RESULTS Gait speed during walking significantly improved in all Vcs compared with Ctrl (P < 0.005), with Vc2, Vc4, and Vc6 identified as the most effective. Gait speed increased (reflecting faster walking) during stair ascent and descent in Vc2 (Ctrl vs. Vc2 for ascent 0.447 Ā± 0.180 vs. 0.517 Ā± 0.127 m/s; P = 0.037 and descent 0.394 Ā± 0.170 vs. 0.487 Ā± 0.125 m/s; P = 0.016), Vc4 (Ctrl vs. Vc4 for ascent 0.447 Ā± 0.180 vs. 0.482 Ā± 0.197 m/s; P = 0.047 and descent 0.394 Ā± 0.170 vs. 0.438 Ā± 0.181 m/s; P = 0.017), and Vc6 (Ctrl vs. Vc6 for ascent 0.447 Ā± 0.180 vs. 0.506 Ā± 0.179 m/s; P = 0.043 and descent 0.394 Ā± 0.170 vs. 0.463 Ā± 0.159 m/s; P = 0.026). Postural balance improved during quiet standing with eyes closed in Vc2, Vc4, Vc6, and Vc7 (P < 0.005). CONCLUSIONS Vibrating insoles are an effective acute strategy for improving postural balance and gait quality during level walking and stair descent in individuals with DPN. These benefits are particularly evident when the entire plantar foot surface is stimulated

    Low-Pathogenic Influenza A Viruses in North American Diving Ducks Contribute to the Emergence of a Novel Highly Pathogenic Influenza A(H7N8) Virus

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    Introductions of low-pathogenic avian influenza (LPAI) viruses of subtypes H5 and H7 into poultry from wild birds have the potential to mutate to highly pathogenic avian influenza (HPAI) viruses, but such virusesā€™ origins are often unclear. In January 2016, a novel H7N8 HPAI virus caused an outbreak in turkeys in Indiana, USA. To determine the virusā€™s origin, we sequenced the genomes of 441 wild-bird origin influenza A viruses (IAVs) from North America and subjected them to evolutionary analyses. The results showed that the H7N8 LPAI virus most likely circulated among diving ducks in the Mississippi flyway during autumn 2015 and was subsequently introduced to Indiana turkeys, in which it evolved high pathogenicity. Preceding the outbreak, an isolate with six gene segments (PB2, PB1, PA, HA, NA, and NS) sharing \u3e99% sequence identity with those of H7N8 turkey isolates was recovered from a diving duck sampled in Kentucky, USA. H4N8 IAVs from other diving ducks possessed five H7N8-like gene segments (PB2, PB1, NA, MP, and NS; \u3e98% sequence identity). Our findings suggest that viral gene constellations circulating among diving ducks can contribute to the emergence of IAVs that affect poultry. Therefore, diving ducks may serve an important and understudied role in the maintenance, diversification, and transmission of IAVs in the wild-bird reservoir

    Genetic evidence supports sporadic and independent introductions of subtype H5 low pathogenic avian influenza A viruses from wild birds to domestic poultry in North America

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    Wild-bird origin influenza A viruses (IAVs or avian influenza) have led to sporadic outbreaks among domestic poultry in the United States and Canada, resulting in economic losses through the implementation of costly containment practices and destruction of birds. We used evolutionary analyses of virus sequence data to determine that 78 H5 low-pathogenic avian influenza viruses (LPAIVs) isolated from domestic poultry in the United States and Canada during 2001 to 2017 resulted from 18 independent virus introductions from wild birds. Within the wild-bird reservoir, the hemagglutinin gene segments of H5 LPAIVs exist primarily as two cocirculating genetic sublineages, and our findings suggest that the H5 gene segments flow within each migratory bird flyway and among adjacent flyways, with limited exchange between the nonadjacent Atlantic and Pacific Flyways. Phylogeographic analyses provided evidence that IAVs from dabbling ducks and swans/geese contributed to the emergence of viruses among domestic poultry. H5 LPAIVs isolated from commercial farm poultry (i.e., turkey) that were descended from a single introduction typically remained a single genotype, whereas those from live-bird markets sometimes led to multiple genotypes, reflecting the potential for reassortment with other IAVs circulating within live-bird markets. H5 LPAIVs introduced from wild birds to domestic poultry represent economic threats to the U.S. poultry industry, and our data suggest that such introductions have been sporadic, controlled effectively through production monitoring and a stamping-out policy, and are, therefore, unlikely to result in sustained detections in commercial poultry operations. IMPORTANCE Integration of viral genome sequencing into influenza surveillance for wild birds and domestic poultry can elucidate evolutionary pathways of economically costly poultry pathogens. Evolutionary analyses of H5 LPAIVs detected in domestic poultry in the United States and Canada during 2001 to 2017 suggest that these viruses originated from repeated introductions of IAVs from wild birds, followed by various degrees of reassortment. Reassortment was observed where biosecurity was low and where opportunities for more than one virus to circulate existed (e.g., congregations of birds from different premises, such as live-bird markets). None of the H5 lineages identified were maintained for the long term in domestic poultry, suggesting that management strategies have been effective in minimizing the impacts of virus introductions on U.S. poultry production

    Low-frequency ventilation during cardiopulmonary bypass for lung protection:A randomized controlled trial

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    OBJECTIVE: Pulmonary dysfunction is a common complication in patients undergoing heart surgery. Current clinical practice does not include any specific strategy for lung protection. To compare the anti-inflammatory effects of low-frequency ventilation (LFV), as measured by nuclear factor Īŗ-light-chain-enhancer of activated B cells (NF-ĪŗB) p65 pathway activation, for the entire cardiopulmonary bypass (CPB) vs both lungs left collapsed in patients undergoing coronary artery bypass grafting (CABG). METHODS: Two groups parallel randomized controlled trial. The primary outcome was inflammation measured by NF-ĪŗB p65 activation in pre- and post-CPB lung biopsies. Secondary outcomes were additional inflammatory markers in both biopsy tissue and blood. RESULTS: Thirty-seven patients were randomly allocated to LFV (18) and to both lungs left collapsed (19). The mean concentration of NF-ĪŗB p65 in the biopsies before chest closure (adjusted for pre-CPB concentration) was higher in the LFV group compared to both lungs left collapsed group but this was not significant (0.102, 95% confidence interval, -0.022 to 0.226, Pā€‰=ā€‰0.104). There were no significant differences between groups in the other inflammatory markers measured in tissue and blood. CONCLUSIONS: In patients undergoing elective CABG, the use of LFV during CPB when compared to both lungs left collapsed does not seem to reduce inflammation in lung biopsies and blood

    Similarities in the immunoglobulin response and V(H )gene usage in rhesus monkeys and humans exposed to porcine hepatocytes

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    BACKGROUND: The use of porcine cells and organs as a source of xenografts for human patients would vastly increase the donor pool; however, both humans and Old World primates vigorously reject pig tissues due to xenoantibodies that react with the polysaccharide galactose Ī± (1,3) galactose (Ī±Gal) present on the surface of many porcine cells. We previously examined the xenoantibody response in patients exposed to porcine hepatocytes via treatment(s) with bioartficial liver devices (BALs), composed of porcine cells in a support matrix. We determined that xenoantibodies in BAL-treated patients are predominantly directed at porcine Ī±Gal carbohydrate epitopes, and are encoded by a small number of germline heavy chain variable region (V(H)) immunoglobulin genes. The studies described in this manuscript were designed to identify whether the xenoantibody responses and the IgV(H )genes encoding antibodies to porcine hepatocytes in non-human primates used as preclinical models are similar to those in humans. Adult non-immunosuppressed rhesus monkeys (Macaca mulatta) were injected intra-portally with porcine hepatocytes or heterotopically transplanted with a porcine liver lobe. Peripheral blood leukocytes and serum were obtained prior to and at multiple time points after exposure, and the immune response was characterized, using ELISA to evaluate the levels and specificities of circulating xenoantibodies, and the production of cDNA libraries to determine the genes used by B cells to encode those antibodies. RESULTS: Xenoantibodies produced following exposure to isolated hepatocytes and solid organ liver grafts were predominantly encoded by genes in the V(H)3 family, with a minor contribution from the V(H)4 family. Immunoglobulin heavy-chain gene (V(H)) cDNA library screening and gene sequencing of IgM libraries identified the genes as most closely-related to the IGHV3-11 and IGHV4-59 germline progenitors. One of the genes most similar to IGHV3-11, V(H)3-11(cyno), has not been previously identified, and encodes xenoantibodies at later time points post-transplant. Sequencing of IgG clones revealed increased usage of the monkey germline progenitor most similar to human IGHV3-11 and the onset of mutations. CONCLUSION: The small number of IGV(H )genes encoding xenoantibodies to porcine hepatocytes in non-human primates and humans is highly conserved. Rhesus monkeys are an appropriate preclinical model for testing novel reagents such as those developed using structure-based drug design to target and deplete antibodies to porcine xenografts

    Heterogeneous N2O5 Uptake During Winter: Aircraft Measurements During the 2015 WINTER Campaign and Critical Evaluation of Current Parameterizations

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    Nocturnal dinitrogen pentoxide (N2O5) heterogeneous chemistry impacts regional air quality and the distribution and lifetime of tropospheric oxidants. Formed from the oxidation of nitrogen oxides, N2O5 is heterogeneously lost to aerosol with a highly variable reaction probability, Ī³(N2O5), dependent on aerosol composition and ambient conditions. Reaction products include soluble nitrate (HNO3 or NO3āˆ’) and nitryl chloride (ClNO2). We report the firstā€ever derivations of Ī³(N2O5) from ambient wintertime aircraft measurements in the critically important nocturnal residual boundary layer. Box modeling of the 2015 Wintertime INvestigation of Transport, Emissions, and Reactivity (WINTER) campaign over the eastern United States derived 2,876 individual Ī³(N2O5) values with a median value of 0.0143 and range of 2 Ɨ 10āˆ’5 to 0.1751. WINTER Ī³(N2O5) values exhibited the strongest correlation with aerosol water content, but weak correlations with other variables, such as aerosol nitrate and organics, suggesting a complex, nonlinear dependence on multiple factors, or an additional dependence on a nonobserved factor. This factor may be related to aerosol phase, morphology (i.e., core shell), or mixing state, none of which are commonly measured during aircraft field studies. Despite general agreement with previous laboratory observations, comparison of WINTER data with 14 literature parameterizations (used to predict Ī³(N2O5) in chemical transport models) confirms that none of the current methods reproduce the full range of Ī³(N2O5) values. Nine reproduce the WINTER median within a factor of 2. Presented here is the first fieldā€based, empirical parameterization of Ī³(N2O5), fit to WINTER data, based on the functional form of previous parameterizations

    Trends and emissions of six perfluorocarbons in the Northern Hemisphere and Southern Hemisphere

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    Perfluorocarbons (PFCs) are potent greenhouse gases with global warming potentials up to several thousand times greater than CO2 on a 100-year time horizon. The lack of any significant sinks for PFCs means that they have long atmospheric lifetimes of the order of thousands of years. Anthropogenic production is thought to be the only source for most PFCs. Here we report an update on the global atmospheric abundances of the following PFCs, most of which have for the first time been analytically separated according to their isomers: c-octafluorobutane (c-C4F8), n-decafluorobutane (n-C4F10), n-dodecafluoropentane (n-C5F12), n-tetradecafluorohexane (n-C6F14), and n-hexadecafluoroheptane (n-C7F16). Additionally, we report the first data set on the atmospheric mixing ratios of perfluoro-2-methylpentane (i-C6F14). The existence and significance of PFC isomers have not been reported before, due to the analytical challenges of separating them. The time series spans a period from 1978 to the present. Several data sets are used to investigate temporal and spatial trends of these PFCs: time series of air samples collected at Cape Grim, Australia, from 1978 to the start of 2018; a time series of air samples collected between July 2015 and April 2017 at Tacolneston, UK; and intensive campaign-based sampling collections from Taiwan. Although the remote ā€œbackgroundā€ Southern Hemispheric Cape Grim time series indicates that recent growth rates of most of these PFCs are lower than in the 1990s, we continue to see significantly increasing mixing ratios that are between 6ā€‰% and 27ā€‰% higher by the end of 2017 compared to abundances measured in 2010. Air samples from Tacolneston show a positive offset in PFC mixing ratios compared to the Southern Hemisphere baseline. The highest mixing ratios and variability are seen in air samples from Taiwan, which is therefore likely situated much closer to PFC sources, confirming predominantly Northern Hemispheric emissions for most PFCs. Even though these PFCs occur in the atmosphere at levels of parts per trillion molar or less, their total cumulative global emissions translate into 833 million metric tonnes of CO2 equivalent by the end of 2017, 23ā€‰% of which has been emitted since 2010. Almost two-thirds of the CO2 equivalent emissions within the last decade are attributable to c-C4F8, which currently also has the highest emission rates that continue to grow. Sources of all PFCs covered in this work remain poorly constrained and reported emissions in global databases do not account for the abundances found in the atmosphere

    When the Well Runs Dry: Modeling Environmental Quenching of High-mass Satellites in Massive Clusters at \boldmathzā‰³1z \gtrsim 1

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    We explore models of massive (>1010Ā MāŠ™\gt 10^{10}~{\rm M}_{\odot}) satellite quenching in massive clusters at zā‰³1z\gtrsim1 using an MCMC framework, focusing on two primary parameters: RquenchR_{\rm quench} (the host-centric radius at which quenching begins) and Ļ„quench\tau_{\rm quench} (the timescale upon which a satellite quenches after crossing RquenchR_{\rm quench}). Our MCMC analysis shows two local maxima in the 1D posterior probability distribution of RquenchR_{\rm quench} at approximately 0.250.25 and 1.0Ā R2001.0~R_{\rm{200}}. Analyzing four distinct solutions in the Ļ„quench\tau_{\rm quench}-RquenchR_{\rm quench} parameter space, nearly all of which yield quiescent fractions consistent with observational data from the GOGREEN survey, we investigate whether these solutions represent distinct quenching pathways and find that they can be separated between \textquote{starvation} and \textquote{core quenching} scenarios. The starvation pathway is characterized by quenching timescales that are roughly consistent with the total cold gas (H2_{2}+H{\scriptsize I}) depletion timescale at intermediate zz, while core quenching is characterized by satellites with relatively high line-of-sight velocities that quench on short timescales (āˆ¼0.25\sim 0.25 Gyr) after reaching the inner region of the cluster (<0.30Ā R200\lt 0.30~R_{\rm{200}}). Lastly, we break the degeneracy between these solutions by comparing the observed properties of transition galaxies from the GOGREEN survey. We conclude that only the \textquote{starvation} pathway is consistent with the projected phase-space distribution and relative abundance of transition galaxies at zāˆ¼1z \sim 1. However, we acknowledge that ram pressure might contribute as a secondary quenching mechanism.Comment: 15 pages; 8 figures; Accepted for publication in Monthly Notices of the Royal Astronomical Societ
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