3,114 research outputs found

    Predictors of willingness to participate in HIV vaccine trials among African Americans

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    African Americans in the United States (U.S.) are disproportionately affected by HIV. Developing an HIV vaccine is an important part of the HIV prevention and treatment toolkit and may help contribute to ending the HIV epidemic. To date, HIV vaccine trials have not engaged representative numbers of African Americans. We evaluated the willingness of African Americans to participate in HIV vaccine trials and identified correlates of willingness to participate (WTP) by surveying African Americans at low- and high-risk of HIV infection in a multi-site, cross-sectional study. We enrolled 1,452 participants; 59% heterosexual women; 21% heterosexual men; 20% men who have sex with men (MSM). Over half of participants (58%) expressed some level of WTP in HIV vaccine trials. Multivariable analyses revealed several variables were positively related to WTP: HIV risk behavior, knowing someone with HIV/AIDS, social support for trial participation, high perception of risk, perceived protection if in a trial, altruism, and greater tolerance for the ambiguous nature of trials (p\u3c0.01). Emphasis on contextual factors related to personal HIV experiences, including knowledge of someone with HIV, and community support for research, may provide effective strategies for engaging African Americans in future HIV vaccine trials

    The effect of neuromuscular electrical stimulation on congenital talipes equinovarus following correction with the Ponseti method: a pilot study.

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    The Ponseti method for clubfoot treatment offers satisfactory initial correction, but success correlates with abduction brace compliance, which is variable. Electrical stimulation as a dynamic intervention to prevent relapses was investigated. Data were compared to a control group. There was a significant improvement in ankle range of motion only in the study group after short-term intervention, and a trend toward greater increase in calf circumference in this group. Parental perception was positive with no compliance issues. This study suggests stimulation is feasible with potential to increase ankle range of motion and facilitate muscle activity. It could be an important adjunct in preventing relapses, however, further studies with larger groups and longer intervention and follow-up duration are necessary

    Regional innovation and spillover effects of foreign direct investment in China: a threshold approach

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    Using a data set on twenty-nine Chinese provinces for the period 1985–2008, this paper establishes a threshold model to analyse the relationship between spillover effects of foreign direct investment (FDI) and regional innovation in China. There is clear evidence of double-threshold effects of regional innovation on productivity spillovers from FDI. Specifically, only when the level of regional innovation reaches the minimum innovation threshold will FDI in the region begin to produce positive productivity spillovers. Furthermore, positive productivity spillovers from FDI will be substantial only when the level of regional innovation attains a higher threshold. The double threshold divides Chinese provinces into three super-regions in terms of innovation, with most provinces positioned within the middle-level innovation super-region. Policy implications are discussed

    Construction and Expected Performance of the Hadron Blind Detector for the PHENIX Experiment at RHIC

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    A new Hadron Blind Detector (HBD) for electron identification in high density hadron environment has been installed in the PHENIX detector at RHIC in the fall of 2006. The HBD will identify low momentum electron-positron pairs to reduce the combinatorial background in the e+ee^{+}e^{-} mass spectrum, mainly in the low-mass region below 1 GeV/c2^{2}. The HBD is a windowless proximity-focusing Cherenkov detector with a radiator length of 50 cm, a CsI photocathode and three layers of Gas Electron Multipliers (GEM). The HBD uses pure CF4_{4} as a radiator and a detector gas. Construction details and the expected performance of the detector are described.Comment: QM2006 proceedings, 4 pages 3 figure

    Forward coherent ϕ\phi-meson photoproduction from deuterons near threshold

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    Differential cross sections and decay asymmetries for coherent ϕ\phi-meson photoproduction from deuterons were measured for the first time at forward angles using linearly polarized photons at EγE_{\gamma}= 1.5-2.4 GeV. This reaction offers a unique way to directly access natural-parity Pomeron dynamics and gluon exchange at low energies. The cross sections at zero degrees increase with increasing photon energy. The decay asymmetries demonstrate a complete dominance of natural-parity exchange processes, showing that isovector unnatural-parity π\pi-meson exchange is small. Nevertheless the deduced cross sections of ϕ\phi-mesons from nucleons contributed by isoscalar t-channel exchange processes are not well described by the conventional Pomeron model.Comment: 14 pages, 6 figures. Final published versio

    The role of perfluorooctane sulfonic acid (PFOS) exposure in inflammation of intestinal tissues and intestinal carcinogenesis

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    PFAS (per- and polyfluoroalkyl substances) are organofluorine substances that are used commercially in products like non-stick cookware, food packaging, personal care products, fire-fighting foam, etc. These chemicals have several different subtypes made of varying numbers of carbon and fluorine atoms. PFAS substances that have longer carbon chains, such as PFOS (perfluorooctane sulfonic acid), can potentially pose a significant public health risk due to their ability to bioaccumulate and persist for long periods of time in the body and the environment. The National Academies Report suggests there is some evidence of PFOS exposure and gastrointestinal (GI) inflammation contributing to ulcerative colitis. Inflammatory bowel diseases such as ulcerative colitis are precursors to colorectal cancer. However, evidence about the association between PFOS and colorectal cancer is limited and has shown contradictory findings. This review provides an overview of population and preclinical studies on PFOS exposure and GI inflammation, metabolism, immune responses, and carcinogenesis. It also highlights some mitigation approaches to reduce the harmful effects of PFOS on GI tract and discusses the dietary strategies, such as an increase in soluble fiber intake, to reduce PFOS-induced alterations in cellular lipid metabolism. More importantly, this review demonstrates the urgent need to better understand the relationship between PFOS and GI pathology and carcinogenesis, which will enable development of better approaches for interventions in populations exposed to high levels of PFAS, and in particular to PFOS

    Inhalation of the Rho-kinase inhibitor Y-27632 reverses allergen-induced airway hyperresponsiveness after the early and late asthmatic reaction

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    BACKGROUND: In guinea pigs, we have previously demonstrated that the contribution of Rho-kinase to airway responsiveness in vivo and ex vivo is enhanced after active sensitization with ovalbumin (OA). Using conscious, unrestrained OA-sensitized guina pigs, we now investigated the role of Rho-kinase in the development of airway hyperresponsiveness (AHR) after the allergen-induced early (EAR) and late asthmatic reaction (LAR) in vivo. METHODS: Histamine and PGF(2α )PC(100)-values (provocation concentrations causing 100% increase in pleural pressure) were assessed before OA-challenge (basal airway responsiveness) and after the OA-induced EAR (5 h after challenge) and LAR (23 h after challenge). Thirty minutes later, saline or the specific Rho-kinase inhibitor Y-27632 (5 mM, nebulizer concentration) were nebulized, after which PC(100)-values were reassessed. RESULTS: In contrast to saline, Y-27632 inhalation significantly decreased the basal responsiveness toward histamine and PGF(2α )before OA-challenge, as indicated by increased PC(100 )-values. Both after the allergen-induced EAR and LAR, AHR to histamine and PGF(2α )was present, which was reversed by Y-27632 inhalation. Moreover, there was an increased effectiveness of Y-27632 to reduce airway responsiveness to histamine and PGF(2α )after the EAR and LAR as compared to pre-challenge conditions. Saline inhalations did not affect histamine or PGF(2α )PC(100)-values at all. Interestingly, under all conditions Y-27632 was significantly more effective in reducing airway responsiveness to PGF(2α )as compared to histamine. Also, there was a clear tendency (P = 0.08) to a more pronounced degree of AHR after the EAR for PGF(2α )than for histamine. CONCLUSION: The results indicate that inhalation of the Rho-kinase inhibitor Y-27632 causes a considerable bronchoprotection to both histamine and PGF(2α). Moreover, the results are indicative of a differential involvement of Rho-kinase in the agonist-induced airway obstruction in vivo. Increased Rho-kinase activity contributes to the allergen-induced AHR to histamine and PGF(2α )after both the EAR and the LAR, which is effectively reversed by inhalation of Y-27632. Therefore, Rho-kinase can be considered as a potential pharmacotherapeutical target in allergic asthma

    Spatial distribution of photoelectrons participating in formation of x-ray absorption spectra

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    Interpretation of x-ray absorption near-edge structure (XANES) experiments is often done via analyzing the role of particular atoms in the formation of specific peaks in the calculated spectrum. Typically, this is achieved by calculating the spectrum for a series of trial structures where various atoms are moved and/or removed. A more quantitative approach is presented here, based on comparing the probabilities that a XANES photoelectron of a given energy can be found near particular atoms. Such a photoelectron probability density can be consistently defined as a sum over squares of wave functions which describe participating photoelectron diffraction processes, weighted by their normalized cross sections. A fine structure in the energy dependence of these probabilities can be extracted and compared to XANES spectrum. As an illustration of this novel technique, we analyze the photoelectron probability density at the Ti K pre-edge of TiS2 and at the Ti K-edge of rutile TiO2.Comment: Journal abstract available on-line at http://link.aps.org/abstract/PRB/v65/e20511

    Report of the 2005 Snowmass Top/QCD Working Group

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    This report discusses several topics in both top quark physics and QCD at an International Linear Collider (ILC). Issues such as measurements at the ttˉt\bar{t} threshold, including both theoretical and machine requirements, and the determination of electroweak top quark couplings, are reviewed. New results concerning the potential of a 500 GeV e+ee^+e^- collider for measuring WtbWtb couplings and the top quark Yukawa coupling are presented. The status of higher order QCD corrections to jet production cross sections, heavy quark form factors, and longitudinal gauge boson scattering, needed for percent-level studies at the ILC, are reviewed. A new study of the measurement of the hadronic structure of the photon at a γγ\gamma\gamma collider is presented. The effects on top quark properties from several models of new physics, including composite models, Little Higgs theories, and CPT violation, are studied.Comment: 39 pages, many figs; typos fixed and refs added. Contributed to the 2005 International Linear Collider Physics and Detector Workshop and 2nd ILC Accelerator Workshop, Snowmass, Colorado, 14-27 Aug 200
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