204 research outputs found
Extended Emission of Short Gamma-Ray Bursts
Preliminary results of our analysis on the extended emission of short/medium
duration GRBs observed with Swift/BAT are presented. The Bayesian blocks
algorithm is used to analyze the burst durations and the temporal structure of
the lightcurves in different energy bands. We show here the results of three
bursts (GRBs 050724, 061006 and 070714B) that have a prominent soft extended
emission component in our sample. The extended emission of these bursts is a
continuous, flickering-liked component, lasting seconds post the GRB
trigger at 15-25 keV bands. Without considering this component, the three
bursts are classified as short GRBs, with seconds. GRB 060614
has an emission component similar to the extended emission, but this component
has pulse-liked structure, possibly indicating that this emission component is
different from that observed in GRBs 050724, 061006, and 070714B. Further
analysis on the spectral evolution behavior of the extended emission component
is on going.Comment: 2008 Nanjing GRB Conferenc
Perspective of monochromatic gamma-ray line detection with the High Energy cosmic-Radiation Detection (HERD) facility onboard China's Space Station
HERD is the High Energy cosmic-Radiation Detection instrument proposed to
operate onboard China's space station in the 2020s. It is designed to detect
energetic cosmic ray nuclei, leptons and photons with a high energy resolution
( for electrons and photons and for nuclei) and a large
geometry factor ( for electrons and diffuse photons and for nuclei). In this work we discuss the capability of HERD to detect
monochromatic -ray lines, based on simulations of the detector
performance. It is shown that HERD will be one of the most sensitive
instruments for monochromatic -ray searches at energies between
to a few hundred GeV. Above hundreds of GeV, Cherenkov telescopes will
be more sensitive due to their large effective area. As a specific example, we
show that a good portion of the parameter space of a supersymmetric dark matter
model can be probed with HERD.Comment: 9 pages, 7 figures, matches version published in Astropart.Phy
(R)-(+)-3-HydrÂoxy-2-methoxyÂcarbonyl-8-methyl-8-azoniabicycloÂ[3.2.1]octane l-bitartrate
(RS)-(±)-2-MethoxyÂcarbonyl-3-tropinone is an important interÂmediate for the preparation of cocaine and its derivatives. The molecule in the title compound, C10H16NO3
+·C4H5O6
−, is present as the enol tautomer. The six-membered ring adopts a half boat conformation, and the five-membered ring a slightly distorted envelope conformation. There are intra- and interÂmolecular hydrogen bonds involving the hydroxyl, carboxyl groups and quaternary ammonium groups
Time-Dependent Changes in the Bladder Muscle Metabolome After Traumatic Spinal Cord Injury in Rats Using Metabolomics
Purpose The main treatment options of neurogenic bladder remains catheterization and long-term oral medications. Metabolic interventions have shown good therapeutic results in many diseases. To date, no studies have characterized the metabolites of the detrusor muscle during neurogenic bladder. Using metabolomics, new muscle metabolomic signatures were identified to reveal the temporal metabolic profile of muscle during disease progression. Methods We used 42 Sprague-Dawley rats (200±20 g, males) for T10 segmental spinal cord injury modeling and collected detrusor tissue and performed nontargeted metabolomics after sham surgery, 30-minute, 6-hour, 12-hour, 24-hour, 5-day, and 2-week postmodelling, to identify the dysregulated metabolic pathways and key metabolites. Results By comparing mzCloud, mzVault, MassList, we identified a total of 1,271 metabolites and enriched a total of 12 metabolism-related pathways with significant differences (P<0.05) based on Kyoto Encyclopedia of Genes and Genomes analysis. Metabolites in several differential metabolic pathways such as ascorbate and aldarate metabolism, Steroid hormone biosynthesis, and carbon metabolism are altered in a regular manner before and after ridge shock. Conclusions Our study is the first time-based metabolomic study of rat forced urinary muscle after traumatic spinal cord injury, and we identified multiple differential metabolic pathways during injury that may improve long-term management strategies for neurogenic bladder and reduce costs in long-term treatment
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