778 research outputs found

    Sudden Rise in Amplitude of 40 kHz Radio Signal in Relation to Solar Radio Flux

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    Acquired hypogammaglobulinemia in HIV ‐positive subjects after liver transplantation

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    Introduction As more solid organ transplantations are performed in patients infected with human immunodeficiency virus ( HIV ), post‐transplant complications in this population are becoming better defined. Methods Using serum samples from the Solid Organ Transplantation in HIV : Multi‐Site Study, we studied the epidemiology of acquired hypogammaglobulinemia ( HGG ) after liver transplantation ( LT ) in 79 HIV ‐infected individuals with a median CD 4 count at enrollment of 288 (interquartile range 200–423) cells/μL. Quantitative immunoglobulin G (IgG) levels before and after LT were measured, with moderate and severe HGG defined as IgG 350–500 mg/dL and <350 mg/dL, respectively. Incidence, risk factors, and associated outcomes of moderate or worse HGG were evaluated using K aplan– M eier estimator and proportional hazards ( PH ) models. Results The 1‐year cumulative incidence of moderate or worse HGG was 12% (95% confidence interval [ CI ]: 6–22%); no new cases were observed between years 1 and 2. In a multivariate PH model, higher pre‐transplant model for end‐stage liver disease score ( P  = 0.04) and treated acute rejection ( P  = 0.04) were both identified as significant predictors of moderate or worse HGG . There was a strong association of IgG levels <500 mg/dL with non‐opportunistic serious infection (hazard ratio [95% CI ]: 3.5 [1.1–10.6]; P  = 0.03) and mortality (3.2 [1.1–9.4]; P  = 0.04). These associations held after adjustment for important determinants of infection and survival among the entire cohort. Conclusion These results suggest that a proportion of HIV ‐positive LT recipients will develop clinically significant HGG after transplantation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102205/1/tid12139.pd

    Extracts of tamarillo, horned melon, and raspberries, but not extract of pear, inhibit human blood platelet aggregation: Investigating the underlying factors for their differential mechanisms

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    Fruit extracts may be cardioprotective via favorable modulation of platelet-blood vessel interaction. We here show that sugar-free extracts of tamarillo, horned melon (kiwano), and raspberry in a dose-dependent manner inhibited ADP-induced platelet aggregation in platelet-rich plasma. In contrast, pear extract had no such effect. Furthermore, analysisof untargeted metabolites revealed the presence of platelet inhibitory components such as benzoic acid, caffeic acid, and gallic acid in the sugar-free extracts of tamarillo, raspberry, and kiwano, but not in pear extract. All these three fruit extracts inhibited the platelet production of TxB2 and the release of platelet factor 4. In conclusion, our work suggests that tamarillo, raspberry, and kiwano inhibit platelet aggregation partly due to the high levels of anti-platelet compounds such as benzoic, caffeic, and gallic acids

    Measurement of the ground-state distributions in bistable mechanically interlocked molecules using slow scan rate cyclic voltammetry

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    In donor–acceptor mechanically interlocked molecules that exhibit bistability, the relative populations of the translational isomers—present, for example, in a bistable [2]rotaxane, as well as in a couple of bistable [2]catenanes of the donor–acceptor vintage—can be elucidated by slow scan rate cyclic voltammetry. The practice of transitioning from a fast scan rate regime to a slow one permits the measurement of an intermediate redox couple that is a function of the equilibrium that exists between the two translational isomers in the case of all three mechanically interlocked molecules investigated. These intermediate redox potentials can be used to calculate the ground-state distribution constants, K. Whereas, (i) in the case of the bistable [2]rotaxane, composed of a dumbbell component containing π-electron-rich tetrathiafulvalene and dioxynaphthalene recognition sites for the ring component (namely, a tetracationic cyclophane, containing two π-electron-deficient bipyridinium units), a value for K of 10 ± 2 is calculated, (ii) in the case of the two bistable [2]catenanes—one containing a crown ether with tetrathiafulvalene and dioxynaphthalene recognition sites for the tetracationic cyclophane, and the other, tetrathiafulvalene and butadiyne recognition sites—the values for K are orders (one and three, respectively) of magnitude greater. This observation, which has also been probed by theoretical calculations, supports the hypothesis that the extra stability of one translational isomer over the other is because of the influence of the enforced side-on donor–acceptor interactions brought about by both π-electron-rich recognition sites being part of a macrocyclic polyether

    The effects of twisted magnetic field on coronal loops oscillations and dissipation

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    The standing MHD modes in a zero-β\beta cylindrical magnetic flux tube modelled as a straight core surrounded by a magnetically twisted annulus, both embedded in a straight ambient external field is considered. The dispersion relation for the fast MHD waves is derived and solved numerically to obtain the frequencies of both the kink (m=1m=1), and fluting (m=2,3m=2,3) waves. Damping rates due to both viscous and resistive dissipations in presence of the twisted magnetic field is derived and solved numerically for both the kink and fluting waves.Comment: 13 pages, 11 figure

    Anodic dissolution of metals in oxide-free cryolite melts

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    The anodic behavior of metals in molten cryolite-alumina melts has been investigated mostly for use as inert anodes for the Hall-Héroult process. In the present work, gold, platinum, palladium, copper, tungsten, nickel, cobalt and iron metal electrodes were anodically polarized in an oxide-free cryolite melt (11%wt. excess AlF3 ; 5%wt. CaF2) at 1273 K. The aim of the experiments was to characterize the oxidation reactions of the metals occurring without the effect of oxygen-containing dissolved species. The anodic dissolution of each metal was demonstrated, and electrochemical reactions were assigned using reversible potential calculation. The relative stability of metals as well as the possibility of generating pure fluorine is discussed

    High-fidelity simulations of CdTe vapor deposition from a new bond-order potential-based molecular dynamics method

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    CdTe has been a special semiconductor for constructing the lowest-cost solar cells and the CdTe-based Cd1-xZnxTe alloy has been the leading semiconductor for radiation detection applications. The performance currently achieved for the materials, however, is still far below the theoretical expectations. This is because the property-limiting nanoscale defects that are easily formed during the growth of CdTe crystals are difficult to explore in experiments. Here we demonstrate the capability of a bond order potential-based molecular dynamics method for predicting the crystalline growth of CdTe films during vapor deposition simulations. Such a method may begin to enable defects generated during vapor deposition of CdTe crystals to be accurately explored

    Antimony germanium sulphide amorphous thin films fabricated by chemical vapour deposition

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    Antimony germanium sulphide (Sb-Ge-S) amorphous thin films have been directly fabricated on both silica on silicon and commercial glass substrates by means of chemical vapour deposition. These Sb-Ge-S films have been characterized by micro-Raman, scanning electron microscopy and energy dispersive X-ray analysis techniques. The analysis results for these amorphous films indicate the composition of Sb-Ge-S can be varied by changing the deposition temperatures. The quality of these Sb-Ge-S amorphous thin films gives them high potential for the chalcogenide optical waveguide and device applications

    Optimization of distyryl-Bodipy chromophores for efficient panchromatic sensitization in dye sensitized solar cells

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    Cataloged from PDF version of article.Versatility of Bodipy (4,4-difluoro-4-bora-3a, 4a-diaza-s-indacene) dyes was further expanded in recent dye-sensitized solar cell applications. Here we report a series of derivatives designed to address earlier problems in Bodipy sensitized solar cells. In the best case example, an overall efficiency of a modest 2.46% was achieved, but panchromatic nature of the dyes is quite impressive. This is the best reported efficiency in liquid electrolyte solar cells with Bodipy dyes as photosensitizers

    Synthesis, characterization and thermochemistry of synthetic Pb–As, Pb–Cu and Pb–Zn jarosites

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    The enthalpy of formation from the elements of well characterized Pb-As, Pb-Cu, and Pb-Zn synthetic jarosites, corresponding to chemical formulas (H3O)0.68±0.03Pb0.32±0.002Fe2.86±0.14(SO4)1.69±0.08(AsO4)0.31±0.02(OH)5.59±0.28(H2O)0.41±0.02, (H3O)0.67±0.03Pb0.33±0.02Fe2.71±0.14Cu0.25±0.01(SO4)2±0.00(OH)5.96±0.30(H2O)0.04±0.002 and (H3O)0.57±0.03Pb0.43±0.02Fe2.70±0.14Zn0.21±0.01(SO4)2±0.00(OH)5.95±0.30(H2O)0.05±0.002, was measured by high temperature oxide melt solution calorimetry and gave ΔH°f = -3691.2 ± 8.6 kJ/mol, ΔH°f = -3653.6 ± 8.2 kJ/mol, and ΔH°f = -3669.4 ± 8.4 kJ/mol, respectively. Using estimated entropies, the standard Gibbs free energy of formation from elements at 298 K ΔG°f of the three compounds were calculated to be -3164.8 ± 9.1 kJ/mol, -3131.4 ± 8.7 kJ/mol, and -3153.6 ± 8.9 kJ/mol, respectively. Based on these free energies, their logKsp values are -13.94 ± 1.89, -4.38 ± 1.81 and -3.75 ± 1.80, respectively. For this compounds, a log10{Pb2+} - pH diagram is presented. The diagram shows that the formation of Pb-As jarosite may decrease aqueous arsenic and lead concentrations to meet drinking water standards. The new thermodynamic data confirm that transformation of Pb-As jarosite to plumbojarosite is thermodynamically possible
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