3,886 research outputs found
Variants of the low oxygen sensors EGLN1 and HIF-1AN associated with acute mountain sickness.
Two low oxygen sensors, Egl nine homolog 1 (EGLN1) and hypoxia-inducible factor 1-α inhibitor (HIF-1AN), play pivotal roles in the regulation of HIF-1α, and high altitude adaption may be involved in the pathology of acute mountain sickness (AMS). Here, we aimed to analyze single nucleotide polymorphisms (SNPs) in the untranslated regions of the EGLN1 and HIF-1AN genes and SNPs chosen from a genome-wide adaptation study of the Han Chinese population. To assess the association between EGLN1 and HIF-1AN SNPs and AMS in a Han Chinese population, a case-control study was performed including 190 patients and 190 controls. In total, thirteen SNPs were genotyped using the MassARRAY® MALDI-TOF system. Multiple genetic models were tested; The Akaike's information criterion (AIC) and Bayesian information criterion (BIC) values indicated that the dominant model may serve as the best-fit model for rs12406290 and rs2153364 of significant difference. However, these data were not significant after Bonferroni correction. No significant association was noted between AMS and rs12757362, rs1339894, rs1361384, rs2009873, rs2739513 or rs2486729 before and after Bonferroni correction. Further haplotype analyses indicated the presence of two blocks in EGLN1; one block consists of rs12406290-rs2153364, located upstream of the EGLN1 gene. Carriers of the "GG" haplotype of rs12406290-rs2153364 exhibited an increased risk of AMS after adjustments for age and smoking status. However, no significant association was observed among HIF-1AN 3'-untranslated region (3'-UTR) polymorphisms, haplotype and AMS. Our study indicates that variants in the EGLN1 5'-UTR influence the susceptibility to AMS in a Han Chinese population
The electromagnetic and gravitational-wave radiations of X-ray transient CDF-S XT2
Binary neutron star (NS) mergers may result in remnants of supra-massive or
even stable NS, which have been supported indirectly by observed X-ray plateau
of some gamma-ray bursts (GRBs) afterglow. Recently, Xue et al. (2019)
discovered a X-ray transient CDF-S XT2 that is powered by a magnetar from
merger of double NS via X-ray plateau and following stepper phase. However, the
decay slope after the plateau emission is a little bit larger than the
theoretical value of spin-down in electromagnetic (EM) dominated by losing its
rotation energy. In this paper, we assume that the feature of X-ray emission is
caused by a supra-massive magnetar central engine for surviving thousands of
seconds to collapse black hole. Within this scenario, we present the
comparisons of the X-ray plateau luminosity, break time, and the parameters of
magnetar between CDF-S XT2 and other short GRBs with internal plateau samples.
By adopting the collapse time to constrain the equation of state (EOS), we find
that three EOSs (GM1, DD2, and DDME2) are consistent with the observational
data. On the other hand, if the most released rotation energy of magnetar is
dominated by GW radiation, we also constrain the upper limit of ellipticity of
NS for given EOS, and it is range in . Its GW signal
can not be detected by aLIGO or even for more sensitive Einstein Telescope in
the future.Comment: 13 pages, 5 figures,1 table. Accepted for publication by Research in
Astronomy and Astrophysic
Interaction between Granulation and Small-Scale Magnetic Flux Observed by Hinode
We study the relationship between granular development and magnetic field
evolution in the quiet Sun. 6 typical cases are displayed to exhibit
interaction between granules and magnetic elements, and we have obtained the
following results. (1) A granule develops centrosymmetrically when no magnetic
flux emerges within the granular cell. (2) A granule develops and splits
noncentrosymmetrically while flux emerges at an outer part of the granular
cell. (3) Magnetic flux emergence as a cluster of mixed polarities is detected
at the position of a granule as soon as the granule breaks up. (4) A dipole
emerges accompanying with the development of a granule, and the two elements of
the dipole root in the adjacent intergranular lanes and face each other across
the granule. Advected by the horizontal granular motion, the positive element
of the dipole then cancels with pre-existing negative flux. (5) Flux
cancellation also takes place between a positive element, which is advected by
granular flow, and its surrounding negative flux. (6) While magnetic flux
cancellation takes place at a granular cell, the granule shrinks and then
disappears. (7) Horizontal magnetic fields enhance at the places where dipoles
emerge and where opposite polarities cancel with each other, but only the
horizontal fields between the dipolar elements point orderly from the positive
element to the negative one. Our results reveal that granules and small-scale
magnetic flux influence each other. Granular flow advects magnetic flux, and
magnetic flux evolution suppresses granular development. There exist extremely
large Doppler blue-shifts at the site of one cancelling magnetic element. This
phenomenon may be caused by the upward flow produced by magnetic reconnection
below the photosphere.Comment: 8 figures, 13 pages. RAA, in pres
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