21,779 research outputs found

    Public geospatial datasets as an approach to maximizing efficiency in the collection of site covariates in wildlife–vehicle collision studies

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    Wildlife–vehicle collisions (WVCs) are a major research focus because of increasing human health and safety concerns and the potential for biological impacts on wildlife. A key component of both understanding the causes of WVCs and designing mitigation measures is the collection and analysis of environmental and roadway data at WVC sites. However, collecting these site data can be logistically challenging and potentially dangerous to researchers. We studied the feasibility and accuracy of using public geospatial datasets, particularly Google Earth and Street View, as an alternative approach to assessing WVC onsite covariates. We randomly selected 50 sites from a larger WVC study and measured the topography, habitat type, width of the road median, and presence of fencing at each site as representatives of typical WVC site covariates. We compared the measurements recorded in the fi eld to estimates obtained from public geospatial datasets in the lab. We determined that median topography had the lowest overall accuracy (60%), followed by presence of fencing with accuracy at 75% of sites. By contrast, median habitat type was identified correctly in almost all comparisons (96% overall accuracy). The root mean squared error for median width was 1.15 m overall. Our results suggest that Google platforms may serve as viable alternatives to fi eld data collection for site covariates related to coarse measures of habitat type and some characteristics of road topography, thus reducing time requirements and potential safety risks to researchers in the fi eld. However, there are several crucial caveats to consider when using geospatial platforms, particularly as they relate to 3-dimensional depictions of roadway features. Thus, we urge caution when attempting to use digital platforms to collect data on these covariates

    Polyphosphate in thrombosis, hemostasis, and inflammation

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    This illustrated review focuses on polyphosphate as a potent modulator of the plasma clotting cascade, with possible roles in hemostasis, thrombosis, and inflammation. Polyphosphates are highly anionic, linear polymers of inorganic phosphates that are widespread throughout biology. Infectious microorganisms accumulate polyphosphates with widely varying polymer lengths (from a few phosphates to over a thousand phosphates long), while activated human platelets secrete polyphosphate with a very narrow size distribution (about 60‐100 phosphates long). Work from our lab and others has shown that long‐chain polyphosphate is a potent trigger of clotting via the contact pathway, while polyphosphate of the size secreted by platelets accelerates factor V activation, blocks the anticoagulant activity of tissue factor pathway inhibitor, promotes factor XI activation by thrombin, and makes fibrin fibrils thicker and more resistant to fibrinolysis. Polyphosphate also modulates inflammation by triggering bradykinin release, inhibiting the complement system, and modulating endothelial function. Polyphosphate and nucleic acids have similar physical properties and both will trigger the contact pathway—although polyphosphate is orders of magnitude more procoagulant than either DNA or RNA. Important caveats in these studies include observations that nucleic acids and polyphosphate may co‐purify, and that these preparations can be contaminated with highly procoagulant microparticles if silica‐based purification methods are employed. Polyphosphate has received attention as a possible therapeutic, with some recent studies exploring the use of polyphosphate in a variety of formulations to control bleeding. Other studies are investigating treatments that block polyphosphate function as novel antithrombotics with the possibility of reduced bleeding side effects.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147856/1/rth212162_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/147856/2/rth212162.pd

    Platelet polyphosphate induces fibroblast chemotaxis and myofibroblast differentiation

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    BackgroundPlatelets secrete many pro‐wound healing molecules such as growth factors and cytokines. We found that releasates from activated human platelets induced the differentiation of cultured murine and human fibroblasts into a myofibroblast phenotype. Surprisingly, most of this differentiation‐inducing activity was heat‐stable, suggesting it was not due to the protein component of the releasates. Inorganic polyphosphate is a major constituent of platelet‐dense granules and promotes blood coagulation and inflammation.ObjectivesWe aim to investigate the contribution of polyphosphate on myofibroblast differentiating activity of platelet releasates.MethodsUsing NIH‐3T3 cells and primary human fibroblasts, we examined the effect of human platelet releasates and chemically synthesized polyphosphate on fibroblast differentiation and migration.ResultsWe found that the myofibroblast‐inducing activity of platelet releasates was severely attenuated after incubation with a polyphosphate‐degrading enzyme, and that fibroblasts responded to platelet‐sized polyphosphate by increased levels of α‐smooth muscle actin, stress fibers, and collagen. Furthermore, fibroblasts were chemotactic toward polyphosphate.ConclusionsThese findings indicate that platelet‐derived polyphosphate acts as a cell signaling molecule by inducing murine and human fibroblasts to differentiate into myofibroblasts, a cell type known to drive both wound healing and fibrosing diseases. Polyphosphate therefore not only promotes early wound responses through enhancing fibrin clot formation, but also may play roles in the later stages of wound healing, and, potentially, progression of fibrotic diseases, by recruiting fibroblasts and inducing their differentiation into myofibroblasts.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/163376/2/jth15066_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/163376/1/jth15066.pd

    Presentation and Outcomes After Medical and Surgical Treatment Versus Medical Treatment Alone of Spontaneous Infectious Spondylodiscitis: A Systematic Literature Review and Meta-Analysis.

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    Study Design: Systematic literature review. Objectives: The aims of this study were to (1) describe the clinical features, disabilities, and incidence of neurologic deficits of pyogenic spondylodiscitis prior to treatment and (2) compare the functional outcomes between patients who underwent medical treatment alone or in combination with surgery for pyogenic spondylodiscitis. Methods: A systematic literature review was performed using PubMed according to PRISMA guidelines. No year restriction was put in place. Statistical analysis of pooled data, when documented in the original report (ie, number of patients with desired variable and number of patients evaluated), was conducted to determine the most common presenting symptoms, incidence of pre- and postoperative neurologic deficits, associated comorbidities, infectious pathogens, approach for surgery when performed, and duration of hospitalization. Outcomes data, including return to work status, resolution of back pain, and functional recovery were also pooled among all studies and surgery-specific studies alone. Meta-analysis of studies with subgroup analysis of pain-free outcome in surgical and medical patients was performed. Results: Fifty of 1286 studies were included, comprising 4173 patients undergoing either medical treatment alone or in combination with surgery. Back pain was the most common presenting symptom, reported in 91% of patients. Neurologic deficit was noted in 31% of patients. Conclusion: Medical management remains first-line treatment of infectious pyogenic spondylodiscitis. Surgery may be indicated for progressive pain, persistent infection on imaging, deformity or neurologic deficits. If surgery is required, reported literature shows potential for significant pain reduction, improved neurologic function and a high number of patients returning to a normal functional/work status

    Agricultural Water Management in the Missippi Delta Region of Arkansas

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    Agriculture is the largest use of soil and water resources in eastern Arkansas. This bulletin summarized the recent historical use of soil and water by agriculture and the impact of irrigation on yields of rice, soybeans and cotton. The experiments conducted in the field to quantitatively schedule irrigations of crops are summarized. The results show the close relationship between the irrigation of crops and the extraction of water from the Alluvial Aquifer. The implications of this relationaship for the future are discussed

    Resonant Steps in the Characteristics of a Josephson Junction Coupled to a Transmission Line

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    A novel circuit is described which functions as an electronic analog of lumped element transmission line. The circuit requires only operational amplifiers, resistors, and capacitors. This module was coupled to a Josephsonj unction simulator and current voltage characteristics of the combined system were recorded. Steps were observed at voltages determined by the appropriate line resonances. When the transmission line was terminated with loads less than the characteristic impedance, chaos was seen in the lower steps. Similar results were obtained by numerical integration of the corresponding system of differential equations
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