2,356 research outputs found

    Nitric Oxide Bioavailability and Its Potential Relevance to the Variation in Susceptibility to the Renal and Vascular Complications in Patients With Type 2 Diabetes

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    OBJECTIVE—We compared the renal and systemic vascular (renovascular) response to a reduction of bioavailable nitric oxide (NO) in type 2 diabetic patients without nephropathy and of African and Caucasian heritage. RESEARCH DESIGN AND METHODS—Under euglycemic conditions, renal blood flow was determined by a constant infusion of paraminohippurate and changes in blood pressure and renal vascular resistance estimated before and after an infusion of l-Ng-monomethyl-l-arginine. RESULTS—In the African-heritage group, there was a significant fall in renal blood flow (Δ−46.0 ml/min per 1.73 m(2); P < 0.05) and rise in systolic blood pressure (Δ10.0 mmHg [95% CI 2.3–17.9]; P = 0.017), which correlated with an increase in renal vascular resistance (r(2) = 0.77; P = 0.004). CONCLUSIONS—The renal vasoconstrictive response associated with NO synthase inhibition in this study may be of relevance to the observed vulnerability to renal injury in patients of African heritage

    Sex Differences in Glutathione Peroxidase Activity and Central Obesity in Patients with Type 2 Diabetes at High Risk of Cardio-Renal Disease.

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    Women with type 2 diabetes (T2DM) have an increased susceptibility of developing cardio-renal disease compared to men, the reasons and the mechanisms of this vulnerability are unclear. Since oxidative stress plays a key role in the development of cardio-renal disease, we investigated the relationship between sex, plasma antioxidants status (glutathione peroxidase (GPx-3 activity), vitamin E and selenium), and adiposity in patients with T2DM at high risk of cardio-renal disease. Women compared to men had higher GPx-3 activity (p = 0.02), bio-impedance (p ≤ 0.0001), and an increase in waist circumference in relation to recommended cut off-points (p = 0.0001). Waist circumference and BMI were negatively correlated with GPx-3 activity (p ≤ 0.05 and p ≤ 0.01, respectively) and selenium concentration (p ≤ 0.01 and p ≤ 0.02, respectively). In multiple regression analysis, waist circumference and sex were independent predictors of GPx-3 activity (p ≤ 0.05 and p ≤ 0.05, respectively). The data suggest that increased central fat deposits are associated with reduced plasma antioxidants which could contribute to the future risk of cardio-renal disease. The increased GPx-3 activity in women could represent a preserved response to the disproportionate increase in visceral fat. Future studies should be aimed at evaluating if the modulation of GPx-3 activity reduces cardio-renal risk in men and women with T2DM

    Homotopy types of stabilizers and orbits of Morse functions on surfaces

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    Let MM be a smooth compact surface, orientable or not, with boundary or without it, PP either the real line R1R^1 or the circle S1S^1, and Diff(M)Diff(M) the group of diffeomorphisms of MM acting on C∞(M,P)C^{\infty}(M,P) by the rule h⋅f↦f∘h−1h\cdot f\mapsto f \circ h^{-1}, where h∈Diff(M)h\in Diff(M) and f∈C∞(M,P)f \in C^{\infty}(M,P). Let f:M→Pf:M \to P be a Morse function and O(f)O(f) be the orbit of ff under this action. We prove that πkO(f)=πkM\pi_k O(f)=\pi_k M for k≥3k\geq 3, and π2O(f)=0\pi_2 O(f)=0 except for few cases. In particular, O(f)O(f) is aspherical, provided so is MM. Moreover, π1O(f)\pi_1 O(f) is an extension of a finitely generated free abelian group with a (finite) subgroup of the group of automorphisms of the Reeb graph of ff. We also give a complete proof of the fact that the orbit O(f)O(f) is tame Frechet submanifold of C∞(M,P)C^{\infty}(M,P) of finite codimension, and that the projection Diff(M)→O(f)Diff(M) \to O(f) is a principal locally trivial S(f)S(f)-fibration.Comment: 49 pages, 8 figures. This version includes the proof of the fact that the orbits of a finite codimension of tame action of tame Lie group on tame Frechet manifold is a tame Frechet manifold itsel

    Detection of an ultra-bright submillimeter galaxy in the Subaru/XMM-Newton Deep Field using AzTEC/ASTE

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    We report the detection of an extremely bright (∼\sim37 mJy at 1100 μ\mum and ∼\sim91 mJy at 880 μ\mum) submillimeter galaxy (SMG), AzTEC-ASTE-SXDF1100.001 (hereafter referred to as SXDF1100.001 or Orochi), discovered in 1100 μ\mum observations of the Subaru/XMM-Newton Deep Field using AzTEC on ASTE. Subsequent CARMA 1300 μ\mum and SMA 880 μ\mum observations successfully pinpoint the location of Orochi and suggest that it has two components, one extended (FWHM of ∼\sim 4′′^{\prime\prime}) and one compact (unresolved). Z-Spec on CSO has also been used to obtain a wide band spectrum from 190 to 308 GHz, although no significant emission/absorption lines are found. The derived upper limit to the line-to-continuum flux ratio is 0.1--0.3 (2 σ\sigma) across the Z-Spec band. Based on the analysis of the derived spectral energy distribution from optical to radio wavelengths of possible counterparts near the SMA/CARMA peak position, we suggest that Orochi is a lensed, optically dark SMG lying at z∼3.4z \sim 3.4 behind a foreground, optically visible (but red) galaxy at z∼1.4z \sim 1.4. The deduced apparent (i.e., no correction for magnification) infrared luminosity (LIRL_{\rm IR}) and star formation rate (SFR) are 6×10136 \times 10^{13} L⊙L_{\odot} and 11000 M⊙M_{\odot} yr−1^{-1}, respectively, assuming that the LIRL_{\rm IR} is dominated by star formation. These values suggest that Orochi will consume its gas reservoir within a short time scale (3×1073 \times 10^{7} yr), which is indeed comparable to those in extreme starbursts like the centres of local ULIRGs.Comment: 18 pages, 13 figure

    Pluto's global surface composition through pixel-by-pixel Hapke modeling of New Horizons Ralph/LEISA data

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    On July 14th 2015, NASA's New Horizons mission gave us an unprecedented detailed view of the Pluto system. The complex compositional diversity of Pluto's encounter hemisphere was revealed by the Ralph/LEISA infrared spectrometer on board of New Horizons. We present compositional maps of Pluto defining the spatial distribution of the abundance and textural properties of the volatiles methane and nitrogen ices and non-volatiles water ice and tholin. These results are obtained by applying a pixel-by-pixel Hapke radiative transfer model to the LEISA scans. Our analysis focuses mainly on the large scale latitudinal variations of methane and nitrogen ices and aims at setting observational constraints to volatile transport models. Specifically, we find three latitudinal bands: the first, enriched in methane, extends from the pole to 55deg N, the second dominated by nitrogen, continues south to 35deg N, and the third, composed again mainly of methane, reaches 20deg N. We demonstrate that the distribution of volatiles across these surface units can be explained by differences in insolation over the past few decades. The latitudinal pattern is broken by Sputnik Planitia, a large reservoir of volatiles, with nitrogen playing the most important role. The physical properties of methane and nitrogen in this region are suggestive of the presence of a cold trap or possible volatile stratification. Furthermore our modeling results point to a possible sublimation transport of nitrogen from the northwest edge of Sputnik Planitia toward the south.Comment: 43 pages, 7 figures; accepted for publication in Icaru

    Improved Measurement of the Positive Muon Lifetime and Determination of the Fermi Constant

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    The mean life of the positive muon has been measured to a precision of 11 ppm using a low-energy, pulsed muon beam stopped in a ferromagnetic target, which was surrounded by a scintillator detector array. The result, tau_mu = 2.197013(24) us, is in excellent agreement with the previous world average. The new world average tau_mu = 2.197019(21) us determines the Fermi constant G_F = 1.166371(6) x 10^-5 GeV^-2 (5 ppm). Additionally, the precision measurement of the positive muon lifetime is needed to determine the nucleon pseudoscalar coupling g_P.Comment: As published version (PRL, July 2007

    A high-resolution study of the OH-stretch fundamental of methanol

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    The OH-stretch fundamental of CH3OH has been observed with 0.025 cm-1 resolution between 3430 and 3940 cm-1 and the resulting spectrum deconvoluted using the procedure of P. A. Jansson. Approximately 600 lines have been assigned to a total of 67 P- or R-branch series and some 30 excited state levels have been determined. Of these, 14 belong to the lowest torsional state with n = 0, 13 to N = 1 and 3 to N = 2. A nonlinear least-squares fit to these levels varying the major parameters used by Y. Y. Kwan and D. M. Dennison in their analysis of the normal state produces an rms deviation between observed and calculated levels of 0.51 cm-1. Variation of all the parameters including those of the smaller Kirtman perturbation terms produces only a slight improvement in the fit. Both analyses yield a barrier height of 411 cm-1 in the excited vibrational state as compared to the normal state value of 373 cm-1. A number of unexplained anomalies appear in the spectra including large and irregular changes in the coefficient of J2 + J for different torsion-rotation states.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22170/1/0000601.pd

    Measurement of the Positive Muon Lifetime and Determination of the Fermi Constant to Part-per-Million Precision

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    We report a measurement of the positive muon lifetime to a precision of 1.0 parts per million (ppm); it is the most precise particle lifetime ever measured. The experiment used a time-structured, low-energy muon beam and a segmented plastic scintillator array to record more than 2 x 10^{12} decays. Two different stopping target configurations were employed in independent data-taking periods. The combined results give tau_{mu^+}(MuLan) = 2196980.3(2.2) ps, more than 15 times as precise as any previous experiment. The muon lifetime gives the most precise value for the Fermi constant: G_F(MuLan) = 1.1663788 (7) x 10^-5 GeV^-2 (0.6 ppm). It is also used to extract the mu^-p singlet capture rate, which determines the proton's weak induced pseudoscalar coupling g_P.Comment: Accepted for publication in Phys. Rev. Let
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