20,027 research outputs found

    Pharmacological activation of endogenous protective pathways against oxidative stress under conditions of sepsis

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    Funding The study was funded entirely by institutional funds.Peer reviewedPostprin

    Role of the exchange and correlation potential into calculating the x-ray absorption spectra of half-metallic alloys: the case of Mn and Cu K-edge XANES in Cu2_2MnM (M = Al, Sn, In) Heusler alloys

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    This work reports a theoretical study of the x-ray absorption near-edge structure spectra at both the Cu and the Mn K-edge in several Cu2_2MnM (M= Al, Sn and In) Heusler alloys. Our results show that {\it ab-initio} single-channel multiple-scattering calculations are able of reproducing the experimental spectra. Moreover, an extensive discussion is presented concerning the role of the final state potential needed to reproduce the experimental data of these half-metallic alloys. In particular, the effects of the cluster-size and of the exchange and correlation potential needed in reproducing all the experimental XANES features are discussed.Comment: 15 pages, 5 figure

    Effect of HIV infection and antiretroviral therapy on hepatitis B virus (HBV)-specific T cell responses in patients who have resolved HBV infection

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    Coinfection with hepatitis B virus (HBV) is a common occurrence in human immunodeficiency virus (HIV)–positive patients and an increasing cause of morbidity and mortality. The CD8+ T cell response is critical for long-term control of HBV in patients resolving acute infection. Here, we examine the effect of HIV on HBV-specific CD8+ T cell responses in patients who have resolved HBV infection. A cross-sectional study showed a reduction in HBV-specific CD8+ T cell responses in HIV-positive, HBV-immune patients, compared with those in HIV-negative, HBV-immune patients. A longitudinal study of a subgroup of patients examined whether this attrition could be reversed by effective antiretroviral therapy. The introduction of highly active antiretroviral therapy (HAART) resulted in reconstitution of some HBV-specific CD4+ and CD8+ T cell responses, in association with restoration of CD4+ T cell counts. These data provide a mechanism to account for the observed impairment of control of HBV infection in the setting of HIV infection and support the ability of HAART to reconstitute functionally active T cell responses

    Experimental and finite element analysis of the mouse caudal vertebrae loading model: prediction of cortical and trabecular bone adaptation

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    In this study, we attempt to predict cortical and trabecular bone adaptation in the mouse caudal vertebrae loading model using knowledge of bone's local mechanical environment at the onset of loading. In a previous study, we demonstrated appreciable 25.9 and 11% increases in both trabecular and cortical bone volume density, respectively, when subjecting the fifth caudal vertebrae (C5) of C57BL/6 (B6) mice to an acute loading regime (amplitude of 8N, 3000 cycles, 10 Hz, 3 times a week for 4 weeks). We have also established a validated finite element (FE) model of the C5 vertebra using micro-computed tomography (micro-CT), which characterizes, in 3D, the micro-mechanical strains present in both cortical and trabecular compartments due to the applied loads. To investigate the relationship between load-induced bone adaptation and mechanical strains in-vivo and in-silico data sets were compared. Using data from the previous cross-sectional study, we divided cortical and trabecular compartments into 15 subregions and determined, for each region, a bone formation parameter ΔBV/BS (a cross-sectional measure of the bone volume added to cortical and trabecular surfaces following the described loading regime). Linear regression was then used to correlate mean regional values of ΔBV/BS with mean values of mechanical strains derived from the FE models which were similarly regionalized. The mechanical parameters investigated were strain energy density (SED), the orthogonal strains (e x , e y , e z ) and the three shear strains (e xy , e yz , e zx ). For cortical regions, regression analysis showed SED to correlate extremely well with ΔBV/BS (R 2 =0.82) and e z (R 2=0.89). Furthermore, SED was found to predict expansion of the cortical shell correlating significantly with the regional percentage increases in cortical tissue volume (R 2 = 0.92), cortical marrow volume (R 2 =0.91) and cortical thickness (R 2 = 0.56). For trabecular regions, FE parameters were found not to correlate with load-induced trabecular bone morphology. These results indicate that load-induced cortical morphology can be predicted from population data, whereas the prediction of trabecular morphology requires subject-specific micro- architectur

    Standing Balance Stability and the Effects of Light Touch in Adults With Profound Loss of Vision-An Exploratory Study

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    Purpose: We evaluated the postural stability of adults with inherited profound vision loss and examined the effects of touch on their balance control. Methods: A total of 11 severely-sight impaired patients (mean [SD] age, 51.6 [5.3] years) and 11 control subjects (mean age, 49.7 [5.3] years) participated. Postural stability was measured using a force-balance platform eyes open/closed on a firm/foam surface under 3 test conditions: no touch, light touch, and unrestricted touch (UT), where "touch" involved placing their index finger on a rigid table. Average magnitude of center of foot pressure displacement was calculated. A somatosensory ratio (SR) was used to evaluate the somatosensory contribution to balance. A repeated measures ANOVA was used to investigate the effects of touch on standing balance. Results: Patients had a significantly increased SR compared to control subjects (mean [SD] SR controls = 1.2 [0.2], patients = 1.9 [0.5]; P < 0.01). There was a significant effect of touch, vision, and surface on balance control ("touch" F = 68.1, P < 0.01; "vision" F = 20.1, P < 0.01; "surface" F = 200.8, P < 0.01). Light touch attenuated sway in patients and controls. The effects were greater in controls when their vision was removed, and greater in patients when their somatosensory system was disrupted. Light touch was as effective as UT in attenuating sway. Conclusions: The results of this exploratory study suggest that patients with severe sight impairment show an increased somatosensory contribution to balance control compared to their normally sighted counterparts. Light touch significantly reduces sway amplitude in severely sight impaired adults when standing on the foam surface, that is, when the somatosensory system is perturbed
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