947 research outputs found
Gravitational Corrections to the Energy-Levels of a Hydrogen Atom
The first order perturbations of the energy levels of a hydrogen atom in
central internal gravitational field are investigated. The internal
gravitational field is produced by the mass of the atomic nucleus. The energy
shifts are calculated for the relativistic 1S, 2S, 2P, 3S, 3P, 3D, 4S and 4P
levels with Schwarzschild metric. The calculated results show that the
gravitational corrections are sensitive to the total angular momentum quantum
number.Comment: 7 page
Tracking crystal-melt segregation and magma recharge using zircon trace element data
The Cretaceous Yunshan caldera complex in SE China consists of an unusual coexisting assemblage of peraluminous and peralkaline rhyolites and a resurgent intra-caldera porphyritic quartz monzonite. In this study, we use zircon trace element data to study the compositional differences of zircons from cogenetic magmas and to track the evolution of the entire magmatic system. Our results indicate that the zircons from the peraluminous and peralkaline rhyolites formed from highly evolved compositions with high Hf concentrations and low Ti contents, and low Th/U and Zr/Hf ratios, which are distinct from those of the intrusive porphyritic quartz monzonite. Zircons from the peraluminous and peralkaline rhyolites display overlapping Zr/Hf and Hf, but the zircons from the peralkaline rhyolites have extremely low Eu/Eu* ratios (Peer reviewe
Exploring the multiband gravitational wave background with a semi-analytic galaxy formation model
An enormous number of compact binary systems, spanning from stellar to
supermassive levels, emit substantial gravitational waves during their final
evolutionary stages, thereby creating a stochastic gravitational wave
background (SGWB). We calculate the merger rates of stellar compact binaries
and massive black hole binaries using a semi-analytic galaxy formation model --
Galaxy Assembly with Binary Evolution (GABE) in a unified and self-consistent
approach, followed by an estimation of the multi-band SGWB contributed by those
systems. We find that the amplitudes of the principal peaks of the SGWB energy
density are within one order of magnitude .
This SGWB could easily be detected by the Square Kilometre Array (SKA), as well
as planned interferometric detectors, such as the Einstein Telescope (ET) and
the Laser Interferometer Space Antenna (LISA). The energy density of this
background varies as in SKA band. The shape of
the SGWB spectrum in the frequency range ,Hz could allow the
LISA to distinguish the black hole seed models. The amplitude of the SGWB from
merging stellar binary black holes (BBHs) at Hz is approximately 10
and 100 times greater than those from merging binary neutron stars (BNSs) and
neutron-star-black-hole (NSBH) mergers, respectively. Note that, since the
cosmic star formation rate density predicted by GABE is somewhat lower than
observational results by dex at z < , the amplitude of the
SGWB in the frequency range , Hz may be underestimated by a
similar factor at most.Comment: 12 pages, 5 figure
Polymorphisms and a Haplotype in Heparanase Gene Associations with the Progression and Prognosis of Gastric Cancer in a Northern Chinese Population
Background: Human heparanase plays an important role in cancer development and single nucleotide polymorphisms (SNPs) in the heparanase gene (HPSE) have been shown to be correlated with gastric cancer. The present study examined the associations between individual SNPs or haplotypes in HPSE and susceptibility, clinicopathological parameters and prognosis of gastric cancer in a large sample of the Han population in northern China. Methodology/Principal Findings: Genomic DNA was extracted from formalin-fixed, paraffin-embedded normal gastric tissue samples from 404 patients and from blood from 404 healthy controls. Six SNPs were genotyped by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. A chi-square (x2) test and unconditional logistic regression were used to analyze the risk of gastric cancer; a Log-rank test and Cox proportional hazards model were used to produce survival analysis and a Kaplan-Meier method was used to map survival curves. The mean genotyping success rates were more than 99 % in both groups. Haplotype CA in the block composed of rs11099592 and rs4693608 had a greater distribution in the group of Borrmann types 3 and 4 (P = 0.037), the group of a greater number of lymph node metastases (N3 vs N0 group, P = 0.046), and moreover was correlated to poor survival (CG vs CA: HR = 0.645, 95%CI: 0.421–0.989, P = 0.044). In addition, genotypes rs4693608 AA and rs4364254 TT were associated with poor survival (P = 0.030, HR = 1.527, 95%CI: 1.042–2.238 for rs4693608 AA; P = 0.013, HR = 1.546, 95%CI: 1.096–2.181 for rs4364254 TT). There were n
Non-coding RNAs participate in the regulatory network of CLDN4 via ceRNA mediated miRNA evasion
AbstractThousands of genes have been well demonstrated to play important roles in cancer progression. As genes do not function in isolation, they can be grouped into “networks” based on their interactions. In this study, we discover a network regulating Claudin-4 in gastric cancer. We observe that Claudin-4 is up-regulated in gastric cancer and is associated with poor prognosis. Claudin-4 reinforce proliferation, invasion, and EMT in AGS, HGC-27, and SGC-7901 cells, which could be reversed by miR-596 and miR-3620-3p. In addition, lncRNA-KRTAP5-AS1 and lncRNA-TUBB2A could act as competing endogenous RNAs to affect the function of Claudin-4. Our results suggest that non-coding RNAs play important roles in the regulatory network of Claudin-4. As such, non-coding RNAs should be considered as potential biomarkers and therapeutic targets against gastric cancer.</jats:p
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