726 research outputs found

    A Spectral Line Survey from 138.3 to 150.7 GHZ toward Orion-KL

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    We present the results of a spectral line survey from 138.3 to 150.7 GHz toward Orion-KL. The observations were made using the 14 m radio telescope of Taeduk Radio Astronomy Observatory. Typical system temperatures were between 500 and 700 K, with the sensitivity between 0.020.060.02 - 0.06 K in units of TA\rm T_A^*. A total of 149 line spectra are detected in this survey. Fifty lines have been previously reported, however we find 99 new detections. Among these new lines, 32 are `unidentified', while 67 are from molecular transitions with known identifications. There is no detection of H or He recombination lines. The identified spectra are from a total of 16 molecular species and their isotopic variants. In the range from 138.3 to 150.7 GHz, the strongest spectral line is the J=3-2 transition of CS molecule, followed by transitions of the H2CO\rm H_2CO, CH3OH\rm CH_3OH, CH3CN\rm CH_3CN, and SO2\rm SO_2. Spectral lines from the large organic molecules such as CH3OH\rm CH_3OH, CH3OCH3\rm CH_3OCH_3, HCOOCH3\rm HCOOCH_3, C2H5CN\rm C_2H_5CN and CH3CN\rm CH_3CN are prominent; with 80 % of the identified lines arising from transitions of these molecules. The rotational temperatures and column densities are derived using the standard rotation diagram analysis for CH3OH\rm CH_3OH (13CH3OH\rm ^{13}CH_3OH), HCOOCH3\rm HCOOCH_3, CH3CN\rm CH_3CN and SO2\rm SO_2 with 10270K\rm 10\sim 270 K and 0.220×1015cm2\rm 0.2\sim 20\times 10^{15} cm^{-2}. These estimates are fairly comparable to the values for the same molecule in other frequency regions by other studies.Comment: 10 figures, 2 tex files for a manuscript and tables, accepted to Ap

    Velocity distribution of collapsing starless cores, L694-2 and L1197

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    In an attempt to understand the dynamics of collapsing starless cores, we have onducted a detailed investigation of the velocity fields of two collapsing cores, L694-2 and L1197, with high spatial resolution HCN J=1-0 maps and Monte Carlo radiative transfer alculation. It is found that infall motion is most active in the middle and outer layers outside the central density-flat region, while both the central and outermost parts of the cores are static or exhibit slower motion. Their peak velocities are 0.28 km s^{-1} for L694-2 and 0.20 km s^{-1$ for L1197, which could not be found in simple models. These velocity fields are roughly consistent with the gravitational collapse models of the isothermal core; However, the velocity gradients inside the peak velocity position are steeper than those of the models. Our results also show that the density distributions are ~ r^{-2.5} and ~ r^{-1.5} in the outer part for L694-2 and L1197, respectively. HCN abundance relative to H_2 is spatially almost constant in L694-2 with a value of 7.0 X 10^{-9}, while for L1197, it shows a slight inward increase from 1.7 X 10^{-9} to 3.5 X 10^{-9}.Comment: accepted in Ap

    Microvasculature remodeling in the mouse lower gut during inflammaging

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    Inflammaging is defined as low-grade, chronic, systemic inflammation in aging, in the absence of overt infection. Age-associated deterioration of gastrointestinal function could be ascribed to the inflammaging, although evidence is yet to emerge. Here we show that microvessels in aging mouse intestine were progressively deprived of supportive structures, microvessel-associated pericytes and adherens junction protein vascular endothelial (VE)-cadherin, and became leaky. This alteration was ascribed to up-regulation of angiopoetin-2 in microvascular endothelial cells. Up-regulation of the angiopoietin-2 was by TNF-α, originated from M2-like residential CD206 + macrophages, proportion of which increases as animal ages. It was concluded that antigenic burdens encountered in intestine throughout life create the condition of chronic stage of inflammation, which accumulates M2-like macrophages expressing TNF-α. The TNF-α induces vascular leakage to facilitate recruitment of immune cells into intestine under the chronic inflammatory setting. © Author(s) 2017.1

    Slowly rotating black holes in the Horava-Lifshitz gravity

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    We investigate slowly rotating black holes in the Ho\v{r}ava-Lifshitz (HL) gravity. For ΛW=0\Lambda_W=0 and λ=1\lambda=1, we find a slowly rotating black hole of the Kehagias-Sfetsos solution in asymptotically flat spacetimes. We discuss their thermodynamic properties by computing mass, temperature, angular momentum, and angular velocity on the horizon.Comment: 12 pages, no figures, version to appear in EPJ

    The absence of the Kerr black hole in the Ho\v{r}ava-Lifshitz gravity

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    We show that the Kerr metric does not exist as a fully rotating black hole solution to the modified Ho\v{r}ava-Lifshitz (HL) gravity with ΛW=0\Lambda_W=0 and λ=1\lambda=1 case. We perform it by showing that the Kerr metric does not satisfy full equations derived from the modified HL gravity.Comment: 35 pages, no figure

    Enhanced greenhouse gas emission from exposed sediments along a hydroelectric reservoir during an extreme drought event

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    An active debate has been underway on the magnitude and duration of carbon (C) emissions from hydroelectric reservoirs, yet little attention has been paid to stochastic C emissions from reservoir sediments during extreme climatic events. A rare opportunity for field measurements of CO2 efflux from a hydroelectric reservoir in Korea during an extreme drought event was used to examine how prolonged droughts can affect microbial organic matter processing and the release of CO2, CH4 and N2O from exposed sediments. Chamber measurements of CO2 efflux along an exposed sediment transect, combined with high-frequency continuous sensor measurements of the partial pressure of CO2 (pCO(2)) in the reservoir surface water, exhibited extraordinary pulses of CO2 from exposed sediments and the turbulent inflowing water in contrast to a small CO2 sink in the main water body of the reservoir and a low efflux of CO2 from the flooded sediment. Significant increases in the production of CO2, CH4 and N2O observed in a laboratory incubation of sediments, together with enhanced activities of phenol oxidase and three hydrolases, indicate a temporary activation of microbial organic matter processing in the drying sediment. The results suggest that drought-triggered pulses of greenhouse gas emission from exposed sediments can offset the C accumulation in reservoir sediments over time scales of years to decades, reversing the trend of declining C emissions from aging reservoirsope

    A novel c.-22T>C mutation in GALK1 promoter is associated with elevated galactokinase phenotype

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    <p>Abstract</p> <p>Background</p> <p>Many genetic variations of <it>GALK1 </it>have been identified in the patients with galactokinase (GALK1) deficiency. However, the molecular characteristics of <it>GALK1 </it>in individuals with elevated GALK1 activity are relatively unknown.</p> <p>Methods</p> <p>We investigated the relationship between elevated GALK1 activity and the molecular <it>GALK1 </it>gene variations, and the molecular mechanism underlying elevated GALK1 activity. PCR products from 63 subjects, without any attenuation of galactose degradation enzymes, were sequenced to screen for nucleotide alterations in the <it>GALK1 </it>promoter.</p> <p>Results</p> <p>Three nucleotide substitutions were identified: c.-179A>G, c.-27A>C, and c.-22T>C. With respect to the c.-22T>C mutation, GALK1 activity in 13 subjects with the T/C or C/C genotype was significantly higher than those in 50 subjects with the T/T genotype (p < 0.001). The dual luciferase reporter assay in Hep3B cells showed that the luciferase activity with the <it>GALK1 </it>promoter with the c.-22C mutant allele increased approximately 2.5-fold, compared to that with the c.-22T. A specific DNA-protein complex was observed in an electrophoretic mobility shift assay, with slightly higher affinity to c.-22C than to c.-22T.</p> <p>Conclusion</p> <p>The c.-22T>C mutation, which was observed frequently in individuals with elevated GALK1 activity, increased the expression of a reporter gene through enhanced binding of a currently unidentified nuclear protein. These results suggest that the elevated GALK1 activity resulted from enhanced gene expression, due to nucleotide variation within <it>GALK1 </it>promoter.</p

    Different effects of SGLT2 inhibitors according to the presence and types of heart failure in type 2 diabetic patients

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    Background The effects of sodium-glucose cotransporter 2 inhibitor (SGLT2i) on cardiac function are not fully understood. We investigated the changes in cardiac function in diabetic patients according to the presence and types of heart failure (HF). Methods We retrospectively identified 202 diabetic patients who underwent echocardiography before, and 6 to 24 months after the initiation of SGLT2i. After propensity score matching with diabetic patients without SGLT2i, the study population (n = 304) were categorized into group 1 (without HF nor SGLT2i; n = 76), group 2 (without HF and received SGLT2i; n = 78), group 3 (with HF but without SGLT2i; n = 76), and group 4 (with HF and received SGLT2i; n = 74). Changes in echocardiographic parameters were compared between these 4 groups, and between HF patients with reduced versus preserved ejection fraction (EF). Results After a median 13 months of follow-up, HF patients with SGLT2i showed a significant decrease in left ventricular end-diastolic dimension (LV-EDD; from 57.4 mm [50.0–64.9] to 53.0 mm [48.0–60.0]; p < 0.001) and improvement in LV-EF (from 36.1% [25.6–47.5] to 45.0% [34.8–56.3]; p < 0.001). LV mass index and diastolic parameters also showed improvements in HF patients with SGLT2i. The SGLT2i-induced improvements in cardiac function were more prominent in HF patients than those without HF, and in HFrEF patients than HFpEF patients. Conclusions Use of SGLT2i improved cardiac function in diabetic patients, regardless of the presence of HF. The improvements were more prominent in HF patients, especially in those with HFrEF. These improvements in cardiac function would contribute to the clinical benefit of SGLT2i

    Extremal black holes in the Ho\v{r}ava-Lifshitz gravity

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    We study the near-horizon geometry of extremal black holes in the z=3z=3 Ho\v{r}ava-Lifshitz gravity with a flow parameter λ\lambda. For λ>1/2\lambda>1/2, near-horizon geometry of extremal black holes are AdS2×S2_2 \times S^2 with different radii, depending on the (modified) Ho\v{r}ava-Lifshitz gravity. For 1/3λ1/21/3\le \lambda \le 1/2, the radius v2v_2 of S2S^2 is negative, which means that the near-horizon geometry is ill-defined and the corresponding Bekenstein-Hawking entropy is zero. We show explicitly that the entropy function approach does not work for obtaining the Bekenstein-Hawking entropy of extremal black holes.Comment: 18 pages, v2:some points on Lifshitz black holes claified, v3: version to appear in EJP

    Prognostic implications of left ventricular mass-geometry in patients with no or nonobstructive coronary artery disease

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    Background Coronary computed tomography angiography (CCTA) is widely used as a first-line noninvasive modality that frequently exhibits no or nonobstructive coronary artery disease (CAD) in clinical practice, along with abnormal left ventricular (LV) geometry on echocardiography. However, the combined prognostic value of these findings has not been well elucidated. Therefore, we aimed to evaluate the prognostic implications of abnormal LV geometry in individuals with no or nonobstructive CAD. Methods A total of 5806 subjects with no CAD or nonobstructive CAD (luminal narrowing  95 g/m2 in women and > 115 g/m2 in men, and/or relative wall thickness > 0.42. The primary outcome was all-cause mortality. Results A total of 5803 subjects without significant obstructive CAD (age, 56.6 ± 8.87 years; men, 3884 [66.9%]). Of them, 4045 (69.7%) subjects had normal LV geometry and 1758 (30.3%) had abnormal LV geometry respectively. During a mean follow-up of 6.2 ± 1.48 years, 84 (1.44%) subjects died in the study population. Of these, 56 subjects were from the normal LV geometry group (1.24%) and 28 were from the abnormal LV geometry group (2.32%). Subjects with abnormal LV geometry had significantly worse survival rates (log-rank, p < 0.001). After adjustment for confounding factors, abnormal LV geometry was an independent predictor of all-cause mortality (adjusted hazard ratio, 1.64; 95% confidence interval, 1.04–2.58; p = 0.034). Moreover, abnormal LV geometry was significantly worse in survival when classified as those with no CAD (log-rank, p = 0.024) and nonobstructive CAD (Log-rank, p < 0.001). Conclusions Abnormal LV geometry portends a worse prognosis in subjects with no or nonobstructive CAD. These findings suggest that LV geometry assessment can help improve the stratification of individuals with these CCTA findings.This work was supported by the National Research Foundation of Korea of the Ministry of Science and ICT (Grant No.2020R1C1C1010890)
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