Protective effect of prostacyclin on postischemic acute renal failure in the rat

Protective effect of prostacyclin on postischemic acute renal failure in the rat. Infusion of prostacyclin (PGI2) reportedly attenuates renal ischemic injury in the dog and the rat. In the dog, PGI2 is a potent renal vasodilator; in the rat a direct action on the renal vasculature is not always apparent. To determine whether or not the protective effect of PGI2 on postichemic ARF was hemodynamically mediated, studies were performed in uninephrectomized Sprague–Dawley rats before and after a 40 minute period of complete renal artery occlusion. In response to the preischemic infusion of PGI2 for 30 minutes at 160 ng/kg body wt/min i.v. (N = 7), MAP and RBF fell to 86 ± 7% (P < 0.0001) and 84 ± 9% (P < 0.05) of baseline values, respectively. RVR initially declined to 81 ± 9% of baseline values (P < 0.025) but returned to 102 ± 13% of baseline values prior to the period of ischemia. Following the period of ischemia, reflow of blood in the rats receiving PGI2 was delayed when compared to rats not receiving PGI2 (N = 1). RBF returned to only 76 ± 19% of the initial values in PGI2-treated rats (P < 0.01) but to 90 ± 12% of the initial values in rats receiving buffer alone (NS). Observations made during the ensuing 48 hours in animals treated with either 80 (N = 8) or 160 ng/kg/body wt/min (N = 7) for 30 minutes before and four hours after the period of ischemia indicated that renal function improved to a greater extent in the PGI2-treated animals than in buffer–treated animals (N = 15) as judged by significantly–greater mean values of V, UOsm, UCr and CCr. On the second day after ischemia, CInwas significantly greater in PGI2-treated animals than in the postischemic animals receiving buffer alone (77 ± 45 vs. 33 ± 20 µl/min/100 g body wt; P < 0.05) despite the fact that no differences were found in the mean values of RBF (3.59 ± 1.08 vs. 3.43 ± 0.32 ml/min/100 body wt. Blinded analysis of the histological sections revealed significantly less evidence of tublar epithelial cell necrosis in the PGI2-treated animals (P < 0.005). The data indicate that the protective effect of PGI2 on the renal response to ischemic injury in the Sprague–Dawley rat is not related to changes in RBF or RVR. Instead, the beneficial effect of PGI2may be a result of cytoprotective properties as has been demonstrated in other tissues

Using coupled micropillar compression and micro-Laue diffraction to investigate deformation mechanisms in a complex metallic alloy Al13Co4

In this investigation, we have used in-situ micro-Laue diffraction combined with micropillar compression of focused ion beam milled Al13Co4 complex metallic alloy to study the evolution of deformation in Al13Co4. Streaking of the Laue spots showed that the onset of plastic flow occured at stresses as low as 0.8 GPa, although macroscopic yield only becomes apparent at 2 GPa. The measured misorientations, obtained from peak splitting, enabled the geometrically necessary dislocation density to be estimated as 1.1 x 1013 m-2

NuSTAR observations of X-ray bursts from the magnetar 1E 1048.1-5937

We report the detection of eight bright X-ray bursts from the 6.5-s magnetar 1E 1048.1-5937, during a 2013 July observation campaign with the Nuclear Spectroscopic Telescope Array (NuSTAR). We study the morphological and spectral properties of these bursts and their evolution with time. The bursts resulted in count rate increases by orders of magnitude, sometimes limited by the detector dead time, and showed blackbody spectra with kT=6-8 keV in the T90 duration of 1-4 s, similar to earlier bursts detected from the source. We find that the spectra during the tail of the bursts can be modeled with an absorbed blackbody with temperature decreasing with flux. The bursts flux decays followed a power-law of index 0.8-0.9. In the burst tail spectra, we detect a ~13 keV emission feature, similar to those reported in previous bursts from this source as well as from other magnetars observed with the Rossi X-ray Timing Explorer (RXTE). We explore possible origins of the spectral feature such as proton cyclotron emission, which implies a magnetic field strength of B~2X10^15 G in the emission region. However, the consistency of the energy of the feature in different objects requires further explanation.Comment: 10 pages, 6 figures, accepted for publication in Ap

The Broadband XMM-Newton and NuSTAR X-ray Spectra of Two Ultraluminous X-ray Sources in the Galaxy IC 342

We present results for two Ultraluminous X-ray Sources (ULXs), IC 342 X-1 and IC 342 X-2, using two epochs of XMM-Newton and NuSTAR observations separated by $\sim$7 days. We observe little spectral or flux variability above 1 keV between epochs, with unabsorbed 0.3--30 keV luminosities being $1.04^{+0.08}_{-0.06} \times 10^{40}$ erg s$^{-1}$ for IC 342 X-1 and $7.40\pm0.20 \times 10^{39}$ erg s$^{-1}$ for IC 342 X-2, so that both were observed in a similar, luminous state. Both sources have a high absorbing column in excess of the Galactic value. Neither source has a spectrum consistent with a black hole binary in low/hard state, and both ULXs exhibit strong curvature in their broadband X-ray spectra. This curvature rules out models that invoke a simple reflection-dominated spectrum with a broadened iron line and no cutoff in the illuminating power-law continuum. X-ray spectrum of IC 342 X-1 can be characterized by a soft disk-like black body component at low energies and a cool, optically thick Comptonization continuum at high energies, but unique physical interpretation of the spectral components remains challenging. The broadband spectrum of IC 342 X-2 can be fit by either a hot (3.8 keV) accretion disk, or a Comptonized continuum with no indication of a seed photon population. Although the seed photon component may be masked by soft excess emission unlikely to be associated with the binary system, combined with the high absorption column, it is more plausible that the broadband X-ray emission arises from a simple thin blackbody disk component. Secure identification of the origin of the spectral components in these sources will likely require broadband spectral variability studies.Comment: 12 pages, 11 figures, 5 Tables, Accepted for publication in The Astrophysical Journa

Incidence and etiology of acute renal failure among ambulatory HIV-infected patients

BACKGROUND: Acute renal failure (ARF) is a cause of renal dysfunction in human immunodeficiency virus (HIV)-infected patients. Its incidence and causes have not been studied since the introduction of highly active antiretroviral therapy (HAART) in HIV ambulatory patients. METHODS: This is a prospective cohort study of 754 HIV patients, 18 years or older, seen at a university-based infectious disease clinic between 2000 and 2002. ARF was identified using proportional increases in serum creatinine from baseline and by chart review. Clinical conditions were assessed at the time of the ARF event. ARF incidence rates (IR) were calculated by dividing the number of events by person time at risk. To compare patients with and without ARF, t test or chi-square test were used. RESULTS: Patient's mean age was 40 years; 68% were male and 61% were black. One hundred-eleven ARF events occurred in 71 subjects (IR 5.9 per 100 person-years; 95% CI 4.9, 7.1). ARF was more common in men, in those with CD4 cell count 10,000 copies/mL. These patients more often had acquired immunodeficiency syndrome (AIDS), hepatitis C infection (HCV), and have received HAART. ARF was mainly community-acquired, due to prerenal causes or acute tubular necrosis, and associated with opportunistic infections and drugs. Liver disease was a cause of ARF in HCV-infected patients. CONCLUSION: ARF is common in ambulatory HIV patients. Immunosuppression, infection, and HCV are important conditions associated with ARF in the post-HAART era

What are the social outcomes of climate policies? A systematic map and review of the ex-post literature

It is critical to ensure climate and energy policies are just, equitable and beneficial for communities, both to sustain public support for decarbonisation and address multifaceted societal challenges. Our objective in this article is to examine the diverse social outcomes that have resulted from climate policies, in varying contexts worldwide, over the past few decades. We review 203 ex-post climate policy assessments that analyse social outcomes in the literature. We systematically and comprehensively map out this work, identifying articles on carbon, energy and transport taxes, feed-in-tariffs, subsidies, direct procurement policies, large renewable deployment projects, and other regulatory and market-based interventions. We code each article in terms of their studied social outcomes and effects, with a focus on electricity access, energy affordability, community cohesion, employment, distributional and equity issues, livelihoods and poverty, procedural justice, subjective well-being and drudgery. Our analysis finds that climate and energy policies often fall short of delivering positive social outcomes. Nonetheless, across country contexts and policy types there are manifold examples of climate policymaking that does deliver on both social and climate goals. This requires attending to distributive and procedural justice in policy design, and making use of appropriate mechanisms to ensure that policy costs and benefits are fairly shared. We emphasize the need to further advance ex-post policy assessments and learn about what policies work for a just transition

Formation of a rotating hole from a close limit head-on collision

Realistic black hole collisions result in a rapidly rotating Kerr hole, but simulations to date have focused on nonrotating final holes. Using a new solution of the Einstein initial value equations we present here waveforms and radiation for an axisymmetric Kerr-hole-forming collision starting from small initial separation (the ``close limit'' approximation) of two identical rotating holes. Several new features are present in the results: (i) In the limit of small separation, the waveform is linear (not quadratic) in the separation. (ii) The waveforms show damped oscillations mixing quasinormal ringing of different multipoles.Comment: 4 pages, 4 figures, submitted to PR