2,892 research outputs found

    Health Care Rationing: What it Means

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    Examines issues related to rationing health care by applying its principles to radiology, and using examples from the budget limited British health system. Includes analysis of expenditures on life saving technology, and evaluation research

    An Econometric Examination of the New Federalism

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    macroeconomics, econometrics, Federalism

    Continued Play Following Sport-Related Concussion in United States Youth Soccer

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    International Journal of Exercise Science 13(6): 87-100, 2020. Medical guidelines and legislation in the US call for immediate removal from play and prohibit continued play on the same day if a concussion is suspected. However, there is limited literature examining whether these guidelines and laws are being followed in youth soccer. The purpose of this study was to identify the frequency at which youth soccer players continued play on the same day following sport-related concussion and factors that may be associated with this behavior. A retrospective review of youth soccer players diagnosed at the initial clinic visit with a sport-related concussion was performed. Participants were categorized into groups, those who continued play on the same day as their concussion (PLAY) and those who did not (NO PLAY). Records were reviewed for demographics, injury characteristics, SCAT3™ symptoms, mBESS and ImPACT® results, symptom resolution and return to play protocol initiation. Fifty-eight girls (mean age: 14 years, range: 7-18 years) and 29 boys (mean age: 14.4 years, range: 6-18 years) participated in this study. Thirty of 58 girls (51.7%) continued play the same day compared to only 5 of 29 boys (17.2%; p=0.002). The odds of continued play in girls were 5 times as high as the odds of continued play in boys (OR=5.05; 95% CI, 1.59-19.3). Overall, 35 (40.2%) soccer players continued play on the same day following a concussion. In conclusion, approximately 40% of youth soccer players continued play on the same day as their concussion. Girl soccer players demonstrated a significantly higher frequency of continued play than boys

    GBM heterogeneity as a function of variable epidermal growth factor receptor variant III activity.

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    Abnormal activation of the epidermal growth factor receptor (EGFR) due to a deletion of exons 2-7 of EGFR (EGFRvIII) is a common alteration in glioblastoma (GBM). While this alteration can drive gliomagenesis, tumors harboring EGFRvIII are heterogeneous. To investigate the role for EGFRvIII activation in tumor phenotype we used a neural progenitor cell-based murine model of GBM driven by EGFR signaling and generated tumor progenitor cells with high and low EGFRvIII activation, pEGFRHi and pEGFRLo. In vivo, ex vivo, and in vitro studies suggested a direct association between EGFRvIII activity and increased tumor cell proliferation, decreased tumor cell adhesion to the extracellular matrix, and altered progenitor cell phenotype. Time-lapse confocal imaging of tumor cells in brain slice cultures demonstrated blood vessel co-option by tumor cells and highlighted differences in invasive pattern. Inhibition of EGFR signaling in pEGFRHi promoted cell differentiation and increased cell-matrix adhesion. Conversely, increased EGFRvIII activation in pEGFRLo reduced cell-matrix adhesion. Our study using a murine model for GBM driven by a single genetic driver, suggests differences in EGFR activation contribute to tumor heterogeneity and aggressiveness

    Effect of different sintering methods on bioactivity and release of proteins from PLGA microspheres

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    Macromolecule release from poly(d,l-lactide-co-glycolide) (PLGA) microspheres has been well-characterized, and is a popular approach for delivering bioactive signals from tissue-engineered scaffolds. However, the effect of some processing solvents, sterilization, and mineral incorporation (when used in concert) on long-term release and bioactivity has seldom been addressed. Understanding these effects is of significant importance for microsphere-based scaffolds, given that these scaffolds are becoming increasingly more popular, yet growth factor activity following sintering and/or sterilization is heretofore unknown. The current study evaluated the 6-week release of transforming growth factor (TGF)-β3 and bone morphogenetic protein (BMP)-2 from PLGA and PLGA/hydroxyapatite (HAp) microspheres following exposure to ethanol (EtOH), dense phase carbon dioxide (CO2), or ethylene oxide (EtO). EtO was chosen based on its common use in scaffold sterilization, whereas EtOH and CO2 were chosen given their importance in sintering microspheres together to create scaffolds. Release supernatants were then used in an accelerated cell stimulation study with human bone marrow stromal cells (hBMSCs) with monitoring of gene expression for major chondrogenic and osteogenic markers. Results indicated that in microspheres without HAp, EtOH exposure led to the greatest amount of delivery, whilst those treated with CO2 delivered the least growth factor. In contrast, formulations with HAp released almost half as much protein, regardless of EtOH or CO2 exposure. Notably, EtO exposure was not found to significantly affect the amount of protein released. Cell stimulation studies demonstrated that eluted protein samples performed similarly to positive controls in PLGA-only formulations, and ambiguously in PLGA/HAp composites. In conclusion, the use of EtOH, subcritical CO2, and EtO in microsphere-based scaffolds may have only slight adverse effects, and possibly even desirable effects in some cases, on protein availability and bioactivity

    Interferometric Constraints on Quantum Geometrical Shear Noise Correlations

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    Final measurements and analysis are reported from the first-generation Holometer, the first instrument capable of measuring correlated variations in space-time position at strain noise power spectral densities smaller than a Planck time. The apparatus consists of two co-located, but independent and isolated, 40 m power-recycled Michelson interferometers, whose outputs are cross-correlated to 25 MHz. The data are sensitive to correlations of differential position across the apparatus over a broad band of frequencies up to and exceeding the inverse light crossing time, 7.6 MHz. By measuring with Planck precision the correlation of position variations at spacelike separations, the Holometer searches for faint, irreducible correlated position noise backgrounds predicted by some models of quantum space-time geometry. The first-generation optical layout is sensitive to quantum geometrical noise correlations with shear symmetry---those that can be interpreted as a fundamental noncommutativity of space-time position in orthogonal directions. General experimental constraints are placed on parameters of a set of models of spatial shear noise correlations, with a sensitivity that exceeds the Planck-scale holographic information bound on position states by a large factor. This result significantly extends the upper limits placed on models of directional noncommutativity by currently operating gravitational wave observatories.Comment: Matches the journal accepted versio

    Integrated management of invasive cattails (Typha spp.) for wetland habitat and biofuel in the Northern Great Plains of the United States and Canada: A review

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    On many public lands in the Great Plains region of the USA and Canada, cattail (Typha spp.) growth has far exceeded the 50:50 distribution recommended for optimum wetland wildlife habitat. Excessive cattail growth is the primary concern of wetland managers and its integrated management is reviewed here. The coverage of this mostly hybrid cattail (T. latifolia Ă— T. angustifolia) is often over 90 % and if partially removed for habitat enhancement represents a substantial biomass resource in sites such as conservation wetlands, water retention basins and roadside drainage ditches. Available biomass is estimated to be 3,000 kg/ha assuming a 50 % harvest rate. Cattail control using mowing, herbicides, and burning is expensive, therefore if harvest logistics can be improved along with developing biomass markets, harvest management would become much more viable. Energy values of cattails are comparable to wood pellets at 20 MJ/kg. Cattails can be simultaneously managed for wetland wildlife, harvested for biofuel, serve as a partial substitute for coal, generate carbon credits, and remove phosphorus from the watershed. Cattails extract nitrogen and phosphorous from runoff water that enters rivers and lakes that could be used for agricultural fertiliser while reducing eutrophication. Additionally, rural economies could be boosted by harvesting a renewable energy resource, especially in areas with little fossil fuels or unsustainable biomass practices
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