272 research outputs found
Investigating the Transition Region Explosive Events and Their Relationship to Network Jets
Recent imaging observations with the Interface Region Imaging Spectrograp
(IRIS) have revealed prevalent intermittent jets with apparent speeds of
80--250 km~s from the network lanes in the solar transition region (TR).
On the other hand, spectroscopic observations of the TR lines have revealed the
frequent presence of highly non-Gaussian line profiles with enhanced emission
at the line wings, often referred as explosive events (EEs). Using simultaneous
imaging and spectroscopic observations from IRIS, we investigate the
relationship between EEs and network jets. We first identify EEs from the
Si~{\sc{iv}}~1393.755 {\AA} line profiles in our observations, then examine
related features in the 1330 {\AA} slit-jaw images. Our analysis suggests that
EEs with double peaks or enhancements in both wings appear to be located at
either the footpoints of network jets, or transient compact brightenings. These
EEs are most likely produced by magnetic reconnection. We also find that EEs
with enhancements only at the blue wing are mainly located on network jets,
away from the footpoints. These EEs clearly result from the superposition of
the high-speed network jets on the TR background. In addition, EEs showing
enhancement only at the red wing of the line are often located around the jet
footpoints, possibly caused by the superposition of reconnection downflows on
the background emission. Moreover, we find some network jets that are not
associated with any detectable EEs. Our analysis suggests that some EEs are
related to the birth or propagation of network jets, and that others are not
connected to network jets.Comment: 9 figures; to appear in Ap
Research on Factors Affecting the Use of E-commerce Consumer Credit Services: A Study of Ant Check Later
This study uses “Ant Check Later”, the e-commerce consumer credit service of Alibaba, as the artifact and explores factors affecting its use. This study first summarized initiatives that Alibaba has launched to stimulate the use of “Ant Check Later”. Three factors, bonus, quota lifting, and scenario enrichment, were then distinguished from the initiatives using principal component analysis. These factors were anticipated to affect consumers’ intention to use the service. The research model was tested using 373 respondents collected from an online survey. Results indicate that bonus, quota lifting, and scenario enrichment are three predictors of consumers’ intention to continue using the service, and bonus and scenario enrichment positively affect non-users’ intention to use the service. This study found that scenario enrichment is the most important factor among the three factors in boosting consumers’ behavioral intention toward using the service. Keywords E-commerce consumer credit services, bonus, quota lifting, scenario enrichment, acceptance
Modulation of the major histocompatibility complex by neural stem cell-derived neurotrophic factors used for regenerative therapy in a rat model of stroke
Effect of hydrogen sulfide on PC12 cell injury induced by high ATP concentration
Purpose: To investigate the potential protective effect of hydrogen sulfide against neural cell damage induced by a high-concentration of adenosine triphosphate (ATP).Methods: PC12 cells were incubated with ATP in order to induce cell damage. The extracellular level of H2S and protein expression of cystathionine-β-synthase (CBS) were determined. The PC12 cells pretreated with NaHS, aminooxyacetic acid (AOAA) and KN-62, prior to further incubation with ATP, and the effect of the treatments on cell viability was investigated.Results: High-concentration ATP induced cell death in PC12 cells, and this was accompanied by markedly increased contents of extracellular H2S and CBS expression (p < 0.05). The ATP-induced cytotoxicity was significantly compromised after pretreatment with H2S. (p < 0.05). The viability of PC12 cells pretreated with NaHS and AOAA was significantly higher than that of PC12 cells treated with ATP alone. In addition, the viability of ATP-treated PC12 cells was further markedly increased after pretreatment with NaHS and KN-62 (p < 0.05).Conclusion: ATP induced a concentration- and time-dependent cytotoxicity in PC12 cells via theendogenous H2S/CBS system. Supplementation with exogenous H2S mitigated the cell damageinduced by high concentration of ATP via a specific mechanism which may be specifically related to P2X7R
Genetic variation and recombination analysis of the GP5 (GP5a) gene of PRRSV-2 strains in China from 1996 to 2022
Porcine reproductive and respiratory syndrome virus (PRRSV) has been prevalent in China for more than 25 years and remains one of the most significant pathogens threatening the pig industry. The high rate of mutation and frequent recombination of PRRSV have exacerbated its prevalence, particularly with the emergence of highly pathogenic PRRSV (HP-PRRSV) has significantly increased the pathogenicity of PRRSV, posing a serious threat to the development of Chinese pig farming. To monitor the genetic variation of PRRSV-2 in China, the GP5 sequences of 517 PRRSV-2 strains from 1996 to 2022 were analyzed and phylogenetic trees were constructed. Furthermore, a total of 60 PRRSV strains, originating from various lineages, were carefully chosen for nucleotide and amino acid homologies analysis. The results showed that the nucleotide homologies of the PRRSV GP5 gene ranged from 81.4 to 100.0%, and the amino acid homologies ranged from 78.1 to 100.0%. Similarly, the PRRSV GP5a gene showed 78.0 ~ 100.0% nucleotide homologies and 70.2 ~ 100.0% amino acid homologies. Amino acid sequence comparisons of GP5 and GP5a showed that some mutations, such as substitutions, deletions, and insertions, were found in several amino acid sites in GP5, these mutations were primarily found in the signal peptide region, two highly variable regions (HVRs), and near two T-cell antigenic sites, while the mutation sites of GP5a were mainly concentrated in the transmembrane and intramembrane regions. Phylogenetic analysis showed that the prevalent PRRSV-2 strains in China were divided into lineages 1, 3, 5, and 8. Among these, strains from lineage 8 and lineage 1 are currently the main prevalent strains, lineage 5 and lineage 8 have a closer genetic distance. Recombination analysis revealed that one recombination event occurred in 517 PRRSV-2 strains, this event involved recombination between lineage 8 and lineage 1. In conclusion, this analysis enhances our understanding of the prevalence and genetic variation of PRRSV-2 in China. These findings provide significant insights for the development of effective prevention and control strategies for PRRS and serve as a foundation for future research in this field
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