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- Ergun, R. E., et al.
(author)
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Observations of Particle Acceleration in Magnetic Reconnection-driven Turbulence
- 2020
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In: Astrophysical Journal. - : IOP PUBLISHING LTD. - 0004-637X .- 1538-4357. ; 898:2
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Journal article (peer-reviewed)abstract
- The Magnetospheric Multiscale Mission observes, in detail, charged particle heating and substantial nonthermal acceleration in a region of strong turbulence (vertical bar delta B vertical bar/vertical bar B vertical bar similar to 1, where B is the magnetic field) that surrounds a magnetic reconnection X-line. Magnetic reconnection enables magnetic field annihilation in a volume that far exceeds that of the diffusion region. The formidable magnetic field annihilation breaks into strong, intermittent turbulence with magnetic field energy as the driver. The strong, intermittent turbulence appears to generate the necessary conditions for nonthermal acceleration. It creates intense, localized currents (J) and unusually large-amplitude electric fields (E). The combination of turbulence-generated E and J results in a significant net positive mean of J center dot E, which signifies particle energization. Ion and electron heating rates are such that they experience a fourfold increase from their initial temperature. Importantly, the strong turbulence also generates magnetic holes or depletions in vertical bar B vertical bar that can trap particles. Trapping considerably increases the dwell time of a subset of particles in the turbulent region, which results in significant nonthermal particle acceleration. The direct observation of strong turbulence that is enabled by magnetic reconnection with nonthermal particle acceleration has far-reaching implications, since turbulence in plasmas is pervasive and may occupy significant volumes of the interstellar medium and intergalactic space. For example, strong turbulence from magnetic field annihilation in the supernova nebulae may dominate large volumes. As such, this observed energization process could plausibly contribute to the supply and development of the cosmic-ray spectrum.
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- Furtado, R. H. M., et al.
(author)
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Efficacy and Safety of Dapagliflozin in Type 2 Diabetes According to Baseline Blood Pressure: Observations From DECLARE-TIMI 58 Trial
- 2022
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In: Circulation. - : Ovid Technologies (Wolters Kluwer Health). - 0009-7322 .- 1524-4539. ; 145:21, s. 1581-1591
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Journal article (peer-reviewed)abstract
- BACKGROUND: Dapagliflozin improved heart failure and kidney outcomes in patients with type 2 diabetes (T2DM) with or at high risk for atherosclerotic cardiovascular disease in the DECLARE-TIMI 58 trial (Dapagliflozin Effect on Cardiovascular Events - Thrombolysis in Myocardial Infarction 58). Here, the aim was to analyze the efficacy and safety of dapagliflozin stratified according to baseline systolic blood pressure (SBP). METHODS: The DECLARE-TIMI 58 trial randomly assigned patients with T2DM and either previous atherosclerotic cardiovascular disease or atherosclerotic cardiovascular disease risk factors to dapagliflozin or placebo. Patients were categorized by baseline SBP levels: <120, 120 to 129, 130 to 139, 140 to 159, and >= 160 mm Hg (normal, elevated, stage 1, stage 2, and severe hypertension, respectively). Efficacy outcomes of interest were hospitalization for heart failure and a renal-specific composite outcome (sustained decrease in estimated glomerular filtration rate by 40%, progression to end-stage renal disease, or renal death). Safety outcomes included symptoms of volume depletion, lower extremity amputations, and acute kidney injury. RESULTS: The trial comprised 17160 patients; mean age, 64.0 +/- 6.8 years; 37.4% women; median duration of T2DM, 11 years; 40.6% with prevalent cardiovascular disease. Overall, dapagliflozin reduced SBP by 2.4 mm Hg (95% CI, 1.9-2.9; F<0.0001) compared with placebo at 48 months. The beneficial effects of dapagliflozin on hospitalization for heart failure and renal outcomes were consistent across all baseline SBP categories, with no evidence of modification of treatment effect (P-interactions = 5 0.28 and 0.52, respectively). Among normotensive patients, the hazard ratios were 0.66 (95% CI, 0.42-1.05) and 0.39 95% CI, 0.19-0.78), respectively, for hospitalization for heart failure and the renal-specific outcome. Events of volume depletion, amputation, and acute kidney injury did not differ with dapagliflozin overall or within any baseline SBP group. CONCLUSIONS: In patients with T2DM with or at high atherosclerotic cardiovascular disease risk, dapagliflozin reduced risk for hospitalization for heart failure and renal outcomes regardless of baseline SBP, with no difference in adverse events of interest at any level of baseline SBP. These results indicate that dapagliflozin provides cardiorenal benefits in patients with T2DM at high atherosclerotic cardiovascular disease risk independent of baseline blood pressure.
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- Goodrich, H. R., et al.
(author)
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Understanding the gastrointestinal physiology and responses to feeding in air-breathing Anabantiform fishes
- 2020
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In: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 96:4, s. 986-1003
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Journal article (peer-reviewed)abstract
- The Mekong Delta is host to a large number of freshwater species, including a unique group of facultative air-breathing Anabantiforms. Of these, the striped snakehead (Channa striata), the climbing perch (Anabas testudineus), the giant gourami (Osphronemus goramy) and the snakeskin gourami (Trichogaster pectoralis) are major contributors to aquaculture production in Vietnam. The gastrointestinal responses to feeding in these four species are detailed here. Relative intestinal length was lowest in the snakehead, indicating carnivory, and 5.5-fold greater in the snakeskin, indicating herbivory; climbing perch and giant gourami were intermediate, indicating omnivory. N-waste excretion (ammonia-N + urea-N) was greatest in the carnivorous snakehead and least in the herbivorous snakeskin, whereas the opposite trend was observed for net K+ excretion. Similarly, the more carnivorous species had a greater stomach acidity than the more herbivorous species. Measurements of acid-base flux to water indicated that the greatest postprandial alkaline tide occurred in the snakehead and a potential acidic tide in the snakeskin. Additional findings of interest were high levels of both PCO2 (up to 40 mmHg) and HCO3- (up to 33 mM) in the intestinal chyme of all four of these air-breathing species. Using in vitro gut sac preparations of the climbing perch, it was shown that the intestinal net absorption of fluid, Na+ and HCO3- was upregulated by feeding but not net Cl- uptake, glucose uptake or K+ secretion. Upregulated net absorption of HCO3- suggests that the high chyme (HCO3-) does not result from secretion by the intestinal epithelium. The possibility of ventilatory control of PCO2 to regulate postprandial acid-base balance in these air-breathing fish is discussed.
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