224 research outputs found

    Cyclooxygenase-2 expression is associated with the renal macula densa of patients with Bartter-like syndrome

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    Cyclooxygenase-2 expression is associated with the renal macula densa of patients with Bartter-like syndrome.BackgroundBartter-like syndrome (BLS) is a heterogeneous set of congenital tubular disorders that is associated with significant renal salt and water loss. The syndrome is also marked by increased urinary prostaglandin E2 (PGE2) excretion. In rodents, salt and volume depletion are associated with increased renal macula densa cyclooxygenase-2 (COX-2) expression. The expression of COX-2 in human macula densa has not been demonstrated. The present studies examined whether COX-2 can be detected in macula densa from children with salt-wasting BLS versus control tissues.MethodsThe intrarenal distribution of COX-2 protein and mRNA was analyzed by immunohistochemistry and in situ hybridization in 12 patients with clinically and/or genetically confirmed BLS. Renal tissue rejected for transplantation, from six adult patients not affected by BLS, was also examined.ResultsThe expression of COX-2 immunoreactive protein was observed in cells of the macula densa in 8 out 11 patients with BLS. In situ hybridization confirmed the expression of COX-2 mRNA in the macula densa in 6 out of 10 cases. COX-2 protein was also detected in the macula densa in a patient with congestive heart failure. The expression of COX-2 immunoreactive protein was not observed in cells associated with the macula densa in kidneys from patients without disorders associated with hyper-reninemia.ConclusionThese studies demonstrate that COX-2 may be detected in the macula densa of humans. Since macula densa COX-2 was detected in cases of BLS, renal COX-2 expression may be linked to volume and renin status in humans, as well as in animals

    The Effects of Static Stretching Intensity on Range of Motion and Strength: A Systematic Review

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    The aim of this study was to systematically review the evidence on the outcomes of using different intensities of static stretching on range of motion (ROM) and strength. PubMed, Web of Science and Cochrane controlled trials databases were searched between October 2021 and February 2022 for studies that examined the effects of different static stretching intensities on range of motion and strength. Out of 6285 identified records, 18 studies were included in the review. Sixteen studies examined outcomes on ROM and four on strength (two studies included outcomes on both ROM and strength). All studies demonstrated that static stretching increased ROM; however, eight studies demonstrated that higher static stretching intensities led to larger increases in ROM. Two of the four studies demonstrated that strength decreased more following higher intensity stretching versus lower intensity stretching. It appears that higher intensity static stretching above the point of discomfort and pain may lead to greater increases in ROM, but further research is needed to confirm this. It is unclear if high-intensity static stretching leads to a larger acute decrease in strength than lower intensity static stretching

    Tracking Black Holes in Numerical Relativity

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    This work addresses and solves the problem of generically tracking black hole event horizons in computational simulation of black hole interactions. Solutions of the hyperbolic eikonal equation, solved on a curved spacetime manifold containing black hole sources, are employed in development of a robust tracking method capable of continuously monitoring arbitrary changes of topology in the event horizon, as well as arbitrary numbers of gravitational sources. The method makes use of continuous families of level set viscosity solutions of the eikonal equation with identification of the black hole event horizon obtained by the signature feature of discontinuity formation in the eikonal's solution. The method is employed in the analysis of the event horizon for the asymmetric merger in a binary black hole system. In this first such three dimensional analysis, we establish both qualitative and quantitative physics for the asymmetric collision; including: 1. Bounds on the topology of the throat connecting the holes following merger, 2. Time of merger, and 3. Continuous accounting for the surface of section areas of the black hole sources.Comment: 14 pages, 16 figure

    Spatial variation of hydroclimate in north-eastern North America during the last millennium

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    Climatic expressions of the Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA) vary regionally, with reconstructions often depicting complex spatial patterns of temperature and precipitation change. The characterisation of these spatial patterns helps advance understanding of hydroclimate variability and associated responses of human and natural systems to climate change. Many regions, including north-eastern North America, still lack well-resolved records of past hydrological change. Here, we reconstruct hydroclimatic change over the past millennium using testate amoeba-inferred peatland water table depth reconstructions obtained from fifteen peatlands across Maine, Nova Scotia, Newfoundland and Québec. Spatial comparisons of reconstructed water table depths reveal complex hydroclimatic patterns that varied over the last millennium. The records suggest a spatially divergent pattern across the region during the Medieval Climate Anomaly and the Little Ice Age. Southern peatlands were wetter during the Medieval Climate Anomaly, whilst northern and more continental sites were drier. There is no evidence at the multi-decadal sampling resolution of this study to indicate that Medieval mega-droughts recorded in the west and continental interior of North America extended to these peatlands in the north-east of the continent. Reconstructed Little Ice Age hydroclimate change was spatially variable rather than displaying a clear directional shift or latitudinal trends, which may relate to local temporary permafrost aggradation in northern sites, and reconstructed characteristics of some dry periods during the Little Ice Age are comparable with those reconstructed during the Medieval Climate Anomaly. The spatial hydroclimatic trends identified here suggest that over the last millennium, peatland moisture balance in north-eastern North America has been influenced by changes in the Polar Jet Stream, storm activities and sea surface temperatures in the North Atlantic as well as internal peatland dynamics

    Searching for the light dark gauge boson in GeV-scale experiments

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    We study current constraints and search prospects for a GeV scale vector boson at a range of low energy experiments. It couples to the Standard Model charged particles with a strength <= 10^-3 to 10^-4 of that of the photon. The possibility of such a particle mediating dark matter self-interactions has received much attention recently. We consider searches at low energy high luminosity colliders, meson decays, and fixed target experiments. Based on available data, searches both at colliders and in meson decays can discover or exclude such a scenario if the coupling strength is on the larger side. We emphasize that a dedicated fixed target experiment has a much better potential in searching for such a gauge boson, and outline the desired properties of such an experiment. Two different optimal designs should be implemented to cover the range of coupling strength 10^-3 to 10^-5, and < 10^-5 of the photon, respectively. We also briefly comment on other possible ways of searching for such a gauge boson.Comment: 33 pages, 5 figures; v2: corrected discussion of Upsilon decays, updates to discussion of fixed-target experiments and QED constraints, numerous minor changes, references added; v3: typo corrected relative to the JHEP published versio

    The effect of hyperbaric oxygen and blood platelet injection therapy on the healing of hamstring injuries in rugby players

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    There are a number of ultra-structural and immuno-histochemical studies involving hyperbaric oxygen treatment in skeletal muscle, as well as soft tissue healing. Hyperbaric oxygen therapy, in conjunction with blood platelet injection therapy, serves as a valuable addition to previously known and trusted rehabilitation techniques and protocols for the healing of musculoskeletal or soft tissue injuries. The primary aim of this case report is to describe the effect on the recovery time of hamstring injuries when combining hyperbaric oxygen therapy (HBOT) and platelet rich plasma (PRP) injection therapy with exercise rehabilitation. A retrospective, post-intervention data analysis was used in this case series report. Data, obtained through collaboration with a professional rugby union and an accredited Hyperbaric Medicine (HBOT) Centre, were analysed using the Statistical Programme for the Social Sciences (SPSS) software. The significance value was set at 5%. A significant decrease in the injury time of the hamstring injuries in rugby players was noted, with a 38% reduction in injury time in players with a grade-one injury, and 45.7% reduction in players with a grade-two injury. In terms of recurrent injuries, 62% of players with grade-one injuries remained uninjured after treatment, and the percentage of re-injured players with grade-two injuries was 0% after HBOT, PRP and physical therapy treatment. The notion that the healing time of hamstring injuries will decrease when HBOT and PRP are administered in conjunction with traditional rehabilitation therapy is indicated by the data of this report.http://www.ajol.info/journal_index.php?jid=153&ab=ajpherd2017-11-30am201

    The AdS/QCD Correspondence: Still Undelivered

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    We consider the particle spectrum and event shapes in large N gauge theories in different regimes of the short-distance 't Hooft coupling, lambda. The mesons in the small lambda limit should have a Regge spectrum in order to agree with perturbation theory, while generically the large lambda theories with gravity duals produce spectra reminiscent of KK modes. We argue that these KK-like states are qualitatively different from QCD modes: they are deeply bound states which are sensitive to short distance interactions rather than the flux tube-like states expected in asymptotically free, confining gauge theories. In addition, we also find that the characteristic event shapes for the large lambda theories with gravity duals are close to spherical, very different from QCD-like (small lambda, small N) and Nambu-Goto-like (small lambda, large N) theories which have jets. This observation is in agreement with the conjecture of Strassler on event shapes in large 't Hooft coupling theories, which was recently proved by Hofman and Maldacena for the conformal case. This conclusion does not change even when considering soft-wall backgrounds in the gravity dual. The picture that emerges is the following: theories with small and large lambda are qualitatively different, while theories with small and large N are qualitatively similar. Thus it seems that it is the relative smallness of the 't Hooft coupling in QCD that prevents a reliable AdS/QCD correspondence from emerging, and that reproducing characteristic QCD-like behavior will require genuine stringy dynamics to be incorporated into any putative dual theory.Comment: 32 pages, 15 figures; references added, minor changes, history clarifie

    The polytrauma clinical triad in patients with chronic pain after motor vehicle collision

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    Background: The polytrauma clinical triad (PCT) is a complex disorder composed of three comorbid diagnoses of chronic pain, post-traumatic stress disorder (PTSD), and postconcussion syndrome (PCS). PCT has been documented in veterans returning from deployment, but this is the first report on PCT prevalence in nonmilitary personnel after a motor vehicle collision (MVC). Methods: Data were drawn from routine intake assessments completed by 71 patients referred to a community-based clinic for chronic pain management. All patients completed the posttraumatic stress disorder checklist for the Diagnostic and Statistical Manual of Mental Disorders, fifth edition (PCL-5), and Rivermead Post-Concussion Symptoms Questionnaire (RPQ) during a standardized intake assessment. An additional modified RPQ score was derived to address previously reported symptom overlap between PCS and chronic pain. Results: Standard and modified RPQ scores yielded PCS prevalence rates of 100% and 54.9% in our sample, respectively. Results suggest that a modified RPQ score, limited to visual and vestibular symptoms, may be more useful PCS screening criteria in patients with chronic pain. PTSD screening criteria on the PCL-5 were met by 85.9% of the patients. More than half of the patients referred for chronic pain after MVC met criteria for PCT (52.1%). Patients who met PCT criteria reported worse headache, overall pain, and sleep quality outcomes. Conclusion: Among patients in our sample with chronic pain after MVC, more than half met criteria for PCT. A modified approach to RPQ scoring limited to visual and vestibular symptoms may be required to screen for PCS in these patients

    Dual Vortex Theory of Strongly Interacting Electrons: Non-Fermi Liquid to the (Hard) Core

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    As discovered in the quantum Hall effect, a very effective way for strongly-repulsive electrons to minimize their potential energy is to aquire non-zero relative angular momentum. We pursue this mechanism for interacting two-dimensional electrons in zero magnetic field, by employing a representation of the electrons as composite bosons interacting with a Chern-Simons gauge field. This enables us to construct a dual description in which the fundamental constituents are vortices in the auxiliary boson fields. The resulting formalism embraces a cornucopia of possible phases. Remarkably, superconductivity is a generic feature, while the Fermi liquid is not -- prompting us to conjecture that such a state may not be possible when the interactions are sufficiently strong. Many aspects of our earlier discussions of the nodal liquid and spin-charge separation find surprising incarnations in this new framework.Comment: Modified dicussion of the hard-core model, correcting several mistake

    Perceived and Actual Breast Cancer Risk

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    Perceived risk can influence health behaviors. Studies using various populations and breast cancer risk bias assessment methods have identified both risk over- and underestimation. Among 1803 women in primary care settings, 47 percent were at average epidemiologic risk (Gail-calculated relative risk ±50 percent of age-adjusted population average) and 55 percent perceived themselves to be at average risk (compared to same-age others) but there were mismatches or ‘biases’: 31 percent underestimated personal risk; 26 percent overestimated. Multiple logistic regression revealed that smokers were more likely to overestimate risk. Overestimation decreased with more education. Mammography use did not independently predict perception bias but, among never-screened women aged over 40 years, those contemplating mammograms were most likely to overestimate risk; precontemplators were most likely to underestimate. Implications for research and intervention are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66881/2/10.1177_135910539800300203.pd
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