The evolved solar-type stars 16 Cyg A and B have long been studied as solar analogs, yielding a glimpse into the future of our own Sun. The orbital period of the binary system is too long to provide ...meaningful dynamical constraints on the stellar properties, but asteroseismology can help because the stars are among the brightest in the Kepler field. We present an analysis of three months of nearly uninterrupted photometry of 16 Cyg A and B from the Kepler space telescope. We extract a total of 46 and 41 oscillation frequencies for the two components, respectively, including a clear detection of octupole (l = 3) modes in both stars. We derive the properties of each star independently using the Asteroseismic Modeling Portal, fitting the individual oscillation frequencies and other observational constraints simultaneously. We evaluate the systematic uncertainties from an ensemble of results generated by a variety of stellar evolution codes and fitting methods. The optimal models derived by fitting each component individually yield a common age (t = 6.8 + or - 0.4 Gyr) and initial composition (Z sub(i) = 0.024+ or -0.002, Y sub(i) = 0.25+ or -0.01) within the uncertainties, as expected for the components of a binary system, bolstering our confidence in the reliability of asteroseismic techniques. The longer data sets that will ultimately become available will allow future studies of differential rotation, convection zone depths, and long-term changes due to stellar activity cycles.
Some patients with chronic obstructive pulmonary disease (COPD) benefit from glucocorticoid (GC) treatment, but its mechanism is unclear.
With the help of the Gene Expression Omnibus (GEO) database, ...the key genes and miRNA-mRNA related to the treatment of COPD by GCs were discussed, and the potential mechanism was explained.
The miRNA microarray dataset (GSE76774) and mRNA microarray dataset (GSE36221) were downloaded, and differential expression analysis were performed. Gene Ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed on the differentially expressed genes (DEGs). The protein interaction network of the DEGs in the regulatory network was constructed with the STRING database, and the key genes were screened through Cytoscape. Potential downstream target genes regulated by differentially expressed miRNAs (DEMs) were predicted by the miRWalk3.0 database, and miRNA-mRNA regulatory networks were constructed. Finally, some research results were validated.
① Four DEMs and 83 DEGs were screened; ② GO and KEGG enrichment analysis mainly focused on the PI3K/Akt signalling pathway, ECM receptor interaction, etc.; ③ CD2, SLAMF7, etc. may be the key targets of GC in the treatment of COPD; ④ 18 intersection genes were predicted by the mirwalk 3.0 database, and 9 pairs of miRNA-mRNA regulatory networks were identified; ⑤ The expression of miR-320d-2 and TFCP2L1 were upregulated by dexamethasone in the COPD cell model, while the expression of miR-181a-2-3p and SLAMF7 were downregulated.
In COPD, GC may mediate the expression of the PI3K/Akt signalling pathway through miR-181a-2-3p, miR-320d-2, miR-650, and miR-155-5p, targeting its downstream signal factors. The research results provide new ideas for RNA therapy strategies of COPD, and also lay a foundation for further research.
Low amplitude is the defining characteristic of solar-like oscillations. The space projects Kepler and CoRoT give us a great opportunity to successfully detect such oscillations in numerous targets. ...Achievements of asteroseismology depend on new discoveries of connections between the oscillation frequencies and stellar properties. In the previous studies, the frequency of the maximum amplitude and the large separation between frequencies were used for this purpose. In the present study, we confirm that the large separation between the frequencies has two minima at two different frequency values. These are the signatures of the He II ionization zone, and as such have very strong diagnostic potential. We relate these minima to fundamental stellar properties such as mass, radius, luminosity, age and mass of convective zone. For mass, the relation is simply based on the ratio of the frequency of minimum ... to the frequency of maximum amplitude. These frequency comparisons can be very precisely computed, and thus the mass and radius of a solar-like oscillating star can be determined to high precision. We also develop a new asteroseismic diagram which predicts structural and evolutionary properties of stars with such data. We derive expressions for mass, radius, effective temperature, luminosity and age in terms of purely asteroseismic quantities. For solar-like oscillating stars, we now will have five very important asteroseismic tools (two frequencies of minimum ..., the frequency of maximum amplitude, and the large and small separations between the oscillation frequencies) to decipher properties of stellar interior astrophysics. (ProQuest: ... denotes formulae/symbols omitted.)
Dentinogenesis imperfecta 1 (DGI1, MIM 125490) is an autosomal dominant dental disease characterized by abnormal dentin production and mineralization. The DGI1 locus was recently refined to a 2-Mb ...interval on 4q21 (ref. 1). Here we study three Chinese families carrying DGI1. We find that the affected individuals of two families also presented with progressive sensorineural high-frequency hearing loss (gene DFNA39). We identified three disease-specific mutations within the dentin sialophosphoprotein gene (DSPP) in these three families. We detected a G→A transition at the donor-splicing site of intron 3 in one family without DFNA39, a mutation predicted to result in the skipping of exon 3. In two other families affected with both DGI1 and DFNA39, however, we identified two independent nucleotide transversions in exons 2 and 3 of DSPP, respectively, that cause missense mutations of two adjacent amino-acid residues in the predicted transmembrane region of the protein. Moreover, transcripts of DSPP previously reported to be expressed specifically in teeth are also detected in the inner ear of mice. We have thus demonstrated for the first time that distinct mutations in DSPP are responsible for the clinical manifestations of DGI1 with or without DFNA39.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
NGC 4203 is a nearby early-type galaxy surrounded by a very large, low-column-density H i disc. In this paper, we study the star formation efficiency in the gas disc of NGC 4203 by using the UV, deep ...optical imaging and infrared data. We confirm that the H i disc consists of two distinct components: an inner star-forming ring with radius from ∼1 to ∼3 R
eff and an outer disc. The outer H i disc is nine times more massive than the inner H i ring. At the location of the inner H i ring, we detect spiral-like structure both in the deep g′ − r′ image and in the 8 μm Spitzer-Infrared Array Camera image, extending in radius up to ∼ 3 R
eff. These two gas components have a different star formation efficiency likely due to the different metallicity and dust content. The inner component has a star formation efficiency very similar to the inner regions of late-type galaxies. Although the outer component has a very low star formation efficiency, it is similar to that of the outer regions of spiral galaxies and dwarfs. We suggest that these differences can be explained with different gas origins for the two components such as stellar mass loss for the inner H i ring and accretion from the inter galactic medium for the outer H i disc. The low-level star formation efficiency in the outer H i disc is not enough to change the morphology of NGC 4203, making the depletion time of the H i gas much too long.
Somatic cell nuclear transfer embryos exhibit extensive epigenetic abnormalities, including aberrant methylation and abnormal imprinted gene expression. In this study, a thorough analysis of X ...chromosome inactivation (XCI) was performed in both preimplantation and postimplantation nuclear transfer embryos. Cloned blastocysts reactivated the inactive somatic X chromosome, possibly in a gradient fashion. Analysis of XCI by Xist RNA and Eed protein localization revealed heterogeneity within cloned embryos, with some cells successfully inactivating an X chromosome and others failing to do so. Additionally, a significant proportion of cells contained more than two X chromosomes, which correlated with an increased incidence of tetraploidy. Imprinted XCI, normally found in preimplantation embryos and extraembryonic tissues, was not observed in blastocysts or placentae from later stage clones, although fetuses recapitulated the
Xce effect. We conclude that, although SCNT embryos can reactivate, count, and inactivate X chromosomes, they are not able to regulate XCI consistently. These results illustrate the heterogeneity of epigenetic changes found in cloned embryos.
The small separation (deltaν01, deltaν02 and deltaν13) between oscillations with low degree l is dependent primarily on the sound speed profile within the stellar core, where nuclear evolution ...occurs. The detection of such oscillations in a star offers a very good opportunity to determine the stage of its nuclear evolution, and hence its age. In this context, we investigate the Sun and alpha Cen A and B. For alpha Cen A and B, each of the small separations deltaν01, deltaν02 and deltaν13 gives a different age. Therefore, in our fitting process, we also employ the second difference, defined as νn,2 - 2νn,1+νn,0, which is 2deltaν01 - deltaν02. In addition to this, we use the frequency ratio (νn,0/νn,2). For the Sun, these expressions are equivalent and give an age of about 4.9 - 5.0 Gyr. For alpha Cen A and B, however, the small separation and the second difference give very different ages. This conflict may be resolved by the detection of oscillation frequencies that can be measured much more precisely than the current frequencies. When we fit the models to the observations, we find that (i) Z0 = 0.020, t = 3.50 Gyr and MB = 1.006 Mdotcircle from the small separations deltaν01, deltav02 and deltaν13 of alpha Cen B; and (ii) a variety of solutions from the non-seismic constraints and deltaν02 of alpha Cen A and B, in which the masses of alpha Cen A and B are slightly modified and the age of the system is about 5.2-5.3 Gyr. For Z = 0.025, the closest masses we find to the observed masses are MB = 0.922 Mdotcircle and MA = 1.115 Mdotcircle. The differences between these masses and the corresponding observed masses are about 0.01 Mdotcircle. PUBLICATION ABSTRACT
Purpose : The purpose of this study was to investigate the mechanism of altered retinoic acid receptor β (RARβ) expression during
esophageal squamous carcinogenesis.
Experimental Design : Samples ...were collected from Linzhou, China. The hypermethylation of CpG islands in the promoter region of the RAR β gene was examined by methylation-specific PCR in human esophageal squamous cell carcinoma (ESCC) samples, as well as in
neighboring tissues with normal epithelium, basal cell hyperplasia, and dysplasia. RARβ mRNA expression was determined by
in situ hybridization. The DNA methyltransferase inhibitor 2′-deoxy-5-azacytidine was used to treat the ESCC cell line, and the DNA
hypermethylation status and mRNA expression level were examined.
Results : Two of 17 (12%) normal, 9 of 21 basal cell hyperplasia (43%), 7 of 12 dysplasia (58%), and 14 of 20 ESCC (70%) samples had
hypermethylation of the RAR β promoter region. The loss of RARβ mRNA expression was highly concordant with RAR β promoter CpG island hypermethylation when individual samples were considered in the correlation analysis. Good statistical
correlation between hypermethylation and loss of RARβ expression was revealed. Frequencies of hypermethylation appeared to
increase with the progression of carcinogenesis. In samples from the same patients, if hypermethylation was detected in earlier
lesions, it was usually observed in more severe lesions. In the ESCC cell line KYSE 510, 2′-deoxy-5-azacytidine partially
reversed CpG island hypermethylation and restored RARβ mRNA expression.
Conclusions : The results suggest that hypermethylation of RAR β promoter region is an important mechanism for RAR β gene silencing in esophageal squamous carcinogenesis.
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