432 research outputs found
Characteristics of gamma-ray burst afterglows in the context of non-axisymmetric structured jets
As the most energetic explosions in the Universe, gamma-ray bursts (GRBs) are
commonly believed to be generated by relativistic jets. Recent observational
evidence suggests that the jets producing GRBs are likely to have a structured
nature. Some studies have suggested that non-axisymmetric structured jets may
be formed through internal non-uniform magnetic dissipation processes or the
precession of the central engine. In this study, we analyze the potential
characteristics of GRB afterglows within the framework of non-axisymmetric
structured jets. We simplify the profile of the asymmetric jet as a step
function of the azimuth angle, dividing the entire jet into individual
elements. By considering specific cases, we demonstrate that the velocity,
energy, and line-of-sight direction of each jet element can greatly affect the
behaviour of the overall light curve. The radiative contributions from multiple
elements may lead to the appearance of multiple distinct peaks or plateaus in
the light curve. Furthermore, fluctuations in the rising and declining segments
of each peak can be observed. These findings establish a theoretical foundation
for future investigations into the structural characteristics of GRBs by
leveraging GRB afterglow data.Comment: Monthly Notices of the Royal Astronomical Society, Volume 525, Issue
4, November 2023, Pages 6285-629
ConoServer: updated content, knowledge, and discovery tools in the conopeptide database
ConoServer (http://www.conoserver.org) is a database specializing in the sequences and structures of conopeptides, which are toxins expressed by marine cone snails. Cone snails are carnivorous gastropods, which hunt their prey using a cocktail of toxins that potently subvert nervous system function. The ability of these toxins to specifically target receptors, channels and transporters of the nervous system has attracted considerable interest for their use in physiological research and as drug leads. Since the founding publication on ConoServer in 2008, the number of entries in the database has nearly doubled, the interface has been redesigned and new annotations have been added, including a more detailed description of cone snail species, biological activity measurements and information regarding the identification of each sequence. Automatically updated statistics on classification schemes, three-dimensional structures, conopeptide-bearing species and endoplasmic reticulum signal sequence conservation trends, provide a convenient overview of current knowledge on conopeptides. Transcriptomics and proteomics have began generating massive numbers of new conopeptide sequences, and two dedicated tools have been recently implemented in ConoServer to standardize the analysis of conopeptide precursor sequences and to help in the identification by mass spectrometry of toxins whose sequences were predicted at the nucleic acid level
A comparison about the inhibitory effect of curcunmin and Avastin on the rat corneal neovascularization
AIM: To compare the inhibitory effect of curcunmin and Avastin on the rat corneal neovascularization(CNV), and approach the mechanism of the curcunmin's inhibition. METHODS: CNV was established in thirty SD rats by alkaline burning. Rats were divided equally to group A and group B at random. In group A, right eyes were experimental group A1, treated by 40μmol/L curcunmin solution, and left eyes were control group A2, treated by 0.09% sodium chloride. In group B, right eyes were experimental group group B1, treated by 5g/L avastin, and left eyes were control group B2, treated by 0.09% sodium chloride. Cornea and aqueous humor were collected by time spot. The capillary vessels were study, and the expressions of VEGF were detected by Enzyme-Linked immunosorbnent Assay(ELISA). RESULTS: No toxic effects of the drugs were found. The capillary vessels in experimental group were less than those of control group(P<0.01). No statistical different of the capillary vessels between two drugs were found. The expressions of VEGF in experimental group were less than those in control group(P<0.01). The expressions of VEGF in B1 group were less than in group A1. CONCLUSION: The inhibitory effect to CNV of curcunmin and avastin have no statistical different in the experiment, but curcunmin has the less inhibitory effect to the expressions of VEGF than avastin. Curcunmin may have other mechanism in the inhibitory action on CNV
Effects of methylphenidate on attentional set-shifting in a genetic model of attention-deficit/hyperactivity disorder
Abstract Background Although deficits of attentional set-shifting have been reported in individuals with attention deficit/hyperactivity disorder (ADHD), it is rarely examined in animal models. Methods This study compared spontaneously hypertensive rats (SHRs; a genetic animal model of ADHD) and Wistar-Kyoto (WKY) and Sprague-Dawley (SD) rats (normoactive control strains), on attentional set-shifting task (ASST) performance. Furthermore, the dose-effects of methylphenidate (MPH) on attentional set-shifting of SHR were investigated. In experiment 1, ASST procedures were conducted in SHR, WKY and SD rats of 8 each at the age of 5 weeks. Mean latencies at the initial phase, error types and numbers, and trials to criteria at each stage were recorded. In experiment 2, 24 SHR rats were randomly assigned to 3 groups of 8 each-- MPH-L (lower dose), MPH-H (higher dose), and SHR-vehicle groups. From 3 weeks, they were administered 2.5 mg/kg or 5 mg/kg MPH or saline respectively for 14 consecutive days. All rats were tested in the ASST at the age of 5 weeks. Results The SHRs generally exhibited poorer performance on ASST than the control WKY and SD rats. Significant strain effects on mean latency [F (2, 21) = 639.636, p p p p p Conclusions The SHR may be impaired in discrimination learning, reversal learning and attentional set-shifting. Our study provides evidence that MPH may improve the SHR's performance on attentional set-shifting and lower dose is more effective than higher dose.</p
4-Bromo-2,6-dimethylanilinium bromide monohydrate
In the title compound, C8H11BrN+·Br−·H2O, a network of N—H⋯O, N—H⋯Br and O—H⋯Br hydrogen bonds helps to consolidate the crystal packing
Raw Garlic Consumption and Risk of Liver Cancer: A Population-Based Case-Control Study in Eastern China.
Although the major risk factors for liver cancer have been established, preventive factors for liver cancer have not been fully explored. We evaluated the association between raw garlic consumption and liver cancer in a large population-based case-control study in Eastern China. The study was conducted in Jiangsu, China, from 2003 to 2010. A total of 2011 incident liver cancer cases and 7933 randomly selected population-controls were interviewed. Epidemiological data including raw garlic intake and other exposures were collected, and serum markers of hepatitis B virus (HBV) and hepatitis C virus (HCV) infection were assayed. Overall, eating raw garlic twice or more per week was inversely associated with liver cancer, with an adjusted odds ratio (aOR) of 0.77 (95% confidence interval (CI): 0.62-0.96) compared to those ingesting no raw garlic or less than twice per week. In stratified analyses, high intake of raw garlic was inversely associated with liver cancer among Hepatitis B surface antigen (HBsAg) negative individuals, frequent alcohol drinkers, those having history of eating mold-contaminated food or drinking raw water, and those without family history of liver cancer. Marginal interactions on an additive scale were observed between low raw garlic intake and HBsAg positivity (attributable proportion due to interaction (AP) = 0.31, 95% CI: -0.01-0.62) and heavy alcohol drinking (AP = 0.28, 95% CI: 0.00-0.57). Raw garlic consumption is inversely associated with liver cancer. Such an association shed some light on the potential etiologic role of garlic intake on liver cancer, which in turn might provide a possible dietary intervention to reduce liver cancer in Chinese population
Influence of different processing times on the quality of Polygoni Multiflora Radix by metabolomics based on ultra high performance liquid chromatography with quadrupole timeâ ofâ flight mass spectrometry
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136757/1/jssc5378_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136757/2/jssc5378.pd
Isolation and characterization of Edwardsiella ictaluri strains as pathogens from diseased yellow catfish Pelteobagrus fulvidraco (Richardson) cultured in China
Yellow catfish Pelteobagrus fulvidraco (Richardson) is a commercially important fish generally distributed in Southeast Asian countries. The well-known aetiological agent of enteric septicaemia of catfish, Edwardsiella ictaluri, was isolated from diseased yellow catfish P. fulvidraco (Richardson) reared at two commercial fisheries in China. The economic losses due to the high mortalities (about 50%) caused by this bacterium have been increasing annually. The affected fish presented two different, typical symptoms: pale gills, slight exophthalmia and a 'hole in the head', and haemorrhage on the opercula, in the skin under the jaw, creating a 'hole under the jaw'. These diseases were found frequently in cultured yellow catfish throughout China. The isolates from both outbreaks were all Gram negative, facultatively anaerobic and short rod. Morphological and biochemical tests and phylogenetic analysis based on the 16S rDNA sequences all strongly indicated that these yellow catfish isolates were highly identical to the known E. ictaluri. In addition, the isolates possessed the typical plasmid profile of E. ictaluri. Experimental infection assays were conducted and pathogenicity (by an intraperitoneal injection) was demonstrated in yellow catfish and channel catfish Ictalurus punctatus. The results showed that yellow catfish isolates were quite conservative pheno-typically and genetically, and were able to cause two different, typical symptoms in this fish under unknown conditions and mechanism
- …