177 research outputs found
Radio Plateaus in Gamma-Ray Burst Afterglows and Their Application in Cosmology
The plateau phase in the radio afterglows has been observed in very few
gamma-ray bursts (GRBs), and 27 radio light curves with plateau phase were
acquired from the published literature in this article. We obtain the related
parameters of the radio plateau, such as temporal indexes during the plateau
phase ( and ), break time (\Tbz) and the corresponding
radio flux (). The two parameter Dainotti relation between the break
time of the plateau and the corresponding break luminosity (\Lbz) in radio
band is \Lbz \propto \Tbz^{-1.20\pm0.24}. Including the isotropic energy
\Eiso and the peak energy \Epi, the three parameter correlations for the
radio plateaus are written as \Lbz \propto \Tbz^{-1.01 \pm 0.24} \Eiso^{0.18
\pm 0.09} and \Lbz \propto \Tbz^{-1.18 \pm 0.27} \Epi^{0.05 \pm 0.28},
respectively. The correlations are less consistent with that of X-ray and
optical plateaus, implying that radio plateaus may have a different physical
mechanism. The typical frequencies crossing the observational band may be a
reasonable hypothesis that causes the breaks of the radio afterglows. We
calibrate GRBs empirical luminosity correlations as standard candle for
constraining cosmological parameters, and find that our samples can constrain
the flat CDM model well, while are not sensitive to non-flat
CDM model. By combining GRBs with other probes, such as SN and CMB,
the constraints on cosmological parameters are \om = 0.297\pm0.006 for the
flat CDM model and \om = 0.283\pm0.008, \oL = 0.711\pm0.006 for
the non-flat CDM model, respectively.Comment: 16 pages, 6 figures and 6 tables, accepted for publication in Ap
Recommended from our members
A regulatory mutant on TRIM26 conferring the risk of nasopharyngeal carcinoma by inducing low immune response.
The major histocompatibility complex (MHC) is most closely associated with nasopharyngeal carcinoma (NPC), but the complexity of its genome structure has proven challenging for the discovery of causal MHC loci or genes. We conducted a targeted MHC sequencing in 40 Cantonese NPC patients followed by a two-stage replication in 1065 NPC cases and 2137 controls of Southern Chinese descendent. Quantitative RT-PCR analysis (qRT-PCR) was used to detect gene expression status in 108 NPC and 43 noncancerous nasopharyngeal (NP) samples. Luciferase reporter assay and chromatin immunoprecipitation (ChIP) were used to assess the transcription factor binding site. We discovered that a novel SNP rs117565607_A at TRIM26 displayed the strongest association (OR = 1.909, Pcombined = 2.750 × 10-19 ). We also observed that TRIM26 was significantly downregulated in NPC tissue samples with genotype AA/AT than TT. Immunohistochemistry (IHC) test also found the TRIM26 protein expression in NPC tissue samples with the genotype AA/AT was lower than TT. According to computational prediction, rs117565607 locus was a binding site for the transcription factor Yin Yang 1 (YY1). We observed that the luciferase activity of YY1 which is binding to the A allele of rs117565607 was suppressed. ChIP data showed that YY1 was binding with T not A allele. Significance analysis of microarray suggested that TRIM26 downregulation was related to low immune response in NPC. We have identified a novel gene TRIM26 and a novel SNP rs117565607_A associated with NPC risk by regulating transcriptional process and established a new functional link between TRIM26 downregulation and low immune response in NPC
MS1, a direct target of MS188, regulates the expression of key sporophytic pollen coat protein genes in Arabidopsis
© 2020 Oxford University Press. All rights reserved. Sporophytic pollen coat proteins (sPCPs) derived from the anther tapetum are deposited into pollen wall cavities and function in pollen-stigma interactions, pollen hydration, and environmental protection. In Arabidopsis, 13 highly abundant proteins have been identified in pollen coat, including seven major glycine-rich proteins GRP14, 16, 17, 18, 19, 20, and GRP-oleosin; two caleosin-related family proteins (AT1G23240 and AT1G23250); three lipase proteins EXL4, EXL5 and EXL6, and ATA27/BGLU20. Here, we show that GRP14, 17, 18, 19, and EXL4 and EXL6 fused with green fluorescent protein (GFP) are translated in the tapetum and then accumulate in the anther locule following tapetum degeneration. The expression of these sPCPs is dependent on two essential tapetum transcription factors, MALE STERILE188 (MS188) and MALE STERILITY 1 (MS1). The majority of sPCP genes are up-regulated within 30 h after MS1 induction and could be restored by MS1 expression driven by the MS188 promoter in ms188, indicating that MS1 is sufficient to activate their expression; however, additional MS1 downstream factors appear to be required for high-level sPCP expression. Our ChIP, in vivo transactivation assay, and EMSA data indicate that MS188 directly activates MS1. Together, these results reveal a regulatory cascade whereby outer pollen wall formation is regulated by MS188 followed by synthesis of sPCPs controlled by MS1
Establishment and characterization of immortalized human eutopic endometrial stromal cells.
PROBLEM(#br)The application of primary eutopic endometrial cells from endometriosis patients in research is restricted for short life span, dedifferentiation of hormone responsiveness.(#br)METHOD OF STUDY(#br)Human telomerase reverse transcriptase (hTERT)-induced immortalized cells (iheESCs) were infected by lentivirus. mRNA level was examined by qRT-PCR, and protein expression was quantified by Western blot. CCK-8 and EdU assay were assigned to assess the proliferation. The migration and invasion of cells were assessed by transwell assay. Clone formation assay and nude mouse tumorigenicity assay were used to evaluate colony-formation and tumorigenesis abilities.(#br)RESULTS(#br)hTERT mRNA and protein were significantly expressed higher in iheESCs compared to primary cells. iheESCs grew without morphological change for 42 passages which is much longer than 18 passages of primary cells. There was no obvious difference between primary cells and iheESCs in growth, mobility, and chromosome karyotype. Furthermore, the expression of epithelial-mesenchymal transition (EMT) markers and estrogen/progesterone receptors remained unchanged. The decidualization of iheESCs could be induced by progesterone and cAMP. Estrogen increased the proliferation and mobility of iheESCs, and lipopolysaccharides (LPS) induced the IL-1β and IL-6 promoting inflammatory response. The colony-forming ability of iheESCs, like primary cells, was lower than Ishikawa cells. In addition, tumorigenicity assay indicated that iheESCs were unable to trigger tumor formation in BALB/c nude mouse.(#br)CONCLUSIONS(#br)This study established and characterized iheESCs that kept the cellular physiology of primary cells and were not available with tumorigenic ability. Thus, iheESCs would be useful as in vitro cell model to investigate pathogenesis of endometriosis
Search for Quasi-Periodical Oscillations in Precursors of Short and Long Gamma Ray Bursts
The precursors of short and long Gamma Ray Bursts (SGRBs and LGRBs) can serve
as probes of their progenitors, as well as shedding light on the physical
processes of mergers or core-collapse supernovae. Some models predict the
possible existence of Quasi-Periodically Oscillations (QPO) in the precursors
of SGRBs. Although many previous studies have performed QPO search in the main
emission of SGRBs and LGRBs, so far there was no systematic QPO search in their
precursors. In this work, we perform a detailed QPO search in the precursors of
SGRBs and LGRBs detected by Fermi/GBM from 2008 to 2019 using the power density
spectrum (PDS) in frequency domain and Gaussian processes (GP) in time domain.
We do not find any convinced QPO signal with significance above 3 ,
possibly due to the low fluxes of precursors. Finally, the PDS continuum
properties of both the precursors and main emissions are also studied for the
first time, and no significant difference is found in the distributions of the
PDS slope for precursors and main emissions in both SGRBs and LGRBs.Comment: submitte
Human cytomegalovirus IE1 downregulates Hes1 in neural progenitor cells as a potential E3 ubiquitin ligase
This work was supported by: National Natural Science Foundation of China http://www.nsfc.gov.cn/; #81620108021: Fetal Brain Maldevelopment Caused by Sox2 Downregulation during Congenital Cytomegalovirus Infection; #31600145: The mechanism of HCMV-IE1 regulating Hes1 expression and rhythm in neural progenitor cells; #81571355: Construction of Murine Cytomegalovirus Derived viral tools for Specific Glia Tracing; #81271850: The regulation mechanism of HCMV infection on Notch signaling pathway in NPCs; and Sino-Africa Joint Research Center, Chinese Academy of Sciences http://www.sinafrica.cas.cn/; #SAJC201605: Geographical distribution and genetic variation of pathogens in Africa. This work is tightly linked to or is an important component of the above list projects, and is financially supported by all the fundings.Congenital human cytomegalovirus (HCMV) infection is the leading cause of neurological disabilities in children worldwide, but the mechanisms underlying these disorders are far from well-defined. HCMV infection has been shown to dysregulate the Notch signaling pathway in human neural progenitor cells (NPCs). As an important downstream effector of Notch signaling, the transcriptional regulator Hairy and Enhancer of Split 1 (Hes1) is essential for governing NPC fate and fetal brain development. In the present study, we report that HCMV infection downregulates Hes1 protein levels in infected NPCs. The HCMV 72-kDa immediate-early 1 protein (IE1) is involved in Hes1 degradation by assembling a ubiquitination complex and promoting Hes1 ubiquitination as a potential E3 ubiquitin ligase, followed by proteasomal degradation of Hes1. Sp100A, an important component of PML nuclear bodies, is identified to be another target of IE1-mediated ubiquitination. A C-terminal acidic region in IE1, spanning amino acids 451 to 475, is required for IE1/Hes1 physical interaction and IE1-mediated Hes1 ubiquitination, but is dispensable for IE1/Sp100A interaction and ubiquitination. Our study suggests a novel mechanism linking downregulation of Hes1 protein to neurodevelopmental disorders caused by HCMV infection. Our findings also complement the current knowledge of herpesviruses by identifying IE1 as the first potential HCMV-encoded E3 ubiquitin ligase.Publisher PDFPeer reviewe
Genome-Wide Histone H3K27 Acetylation Profiling Identified Genes Correlated With Prognosis in Papillary Thyroid Carcinoma
Thyroid carcinoma (TC) is the most common endocrine malignancy, and papillary TC (PTC) is the most frequent subtype of TC, accounting for 85–90% of all the cases. Aberrant histone acetylation contributes to carcinogenesis by inducing the dysregulation of certain cancer-related genes. However, the histone acetylation landscape in PTC remains elusive. Here, we interrogated the epigenomes of PTC and benign thyroid nodule (BTN) tissues by applying H3K27ac chromatin immunoprecipitation followed by deep sequencing (ChIP-seq) along with RNA-sequencing. By comparing the epigenomic features between PTC and BTN, we detected changes in H3K27ac levels at active regulatory regions, identified PTC-specific super-enhancer-associated genes involving immune-response and cancer-related pathways, and uncovered several genes that associated with disease-free survival of PTC. In summary, our data provided a genome-wide landscape of histone modification in PTC and demonstrated the role of enhancers in transcriptional regulations associated with prognosis of PTC
Spatiotemporal evolution of online attention to vaccines since 2011: An empirical study in China
Since the outbreak of Coronavirus Disease 2019 (COVID-19), the Chinese government has taken a number of measures to effectively control the pandemic. By the end of 2021, China achieved a full vaccination rate higher than 85%. The Chinese Plan provides an important model for the global fight against COVID-19. Internet search reflects the public's attention toward and potential demand for a particular thing. Research on the spatiotemporal characteristics of online attention to vaccines can determine the spatiotemporal distribution of vaccine demand in China and provides a basis for global public health policy making. This study analyzes the spatiotemporal characteristics of online attention to vaccines and their influencing factors in 31 provinces/municipalities in mainland China with Baidu Index as the data source by using geographic concentration index, coefficient of variation, GeoDetector, and other methods. The following findings are presented. First, online attention to vaccines showed an overall upward trend in China since 2011, especially after 2016. Significant seasonal differences and an unbalanced monthly distribution were observed. Second, there was an obvious geographical imbalance in online attention to vaccines among the provinces/municipalities, generally exhibiting a spatial pattern of “high in the east and low in the west.” Low aggregation and obvious spatial dispersion among the provinces/municipalities were also observed. The geographic distribution of hot and cold spots of online attention to vaccines has clear boundaries. The hot spots are mainly distributed in the central-eastern provinces and the cold spots are in the western provinces. Third, the spatiotemporal differences in online attention to vaccines are the combined result of socioeconomic level, socio-demographic characteristics, and disease control level
- …