1,755 research outputs found
Thermodynamics of Black Holes in Massive Gravity
We present a class of charged black hole solutions in an (-dimensional
massive gravity with a negative cosmological constant, and study thermodynamics
and phase structure of the black hole solutions both in grand canonical
ensemble and canonical ensemble. The black hole horizon can have a positive,
zero or negative constant curvature characterized by constant . By using
Hamiltonian approach, we obtain conserved charges of the solutions and find
black hole entropy still obeys the area formula and the gravitational field
equation at the black hole horizon can be cast into the first law form of black
hole thermodynamics. In grand canonical ensemble, we find that thermodynamics
and phase structure depends on the combination in the
four dimensional case, where is the chemical potential and is
the coefficient of the second term in the potential associated with graviton
mass. When it is positive, the Hawking-Page phase transition can happen, while
as it is negative, the black hole is always thermodynamically stable with a
positive capacity. In canonical ensemble, the combination turns out to be
in the four dimensional case. When it is positive, a first order
phase transition can happen between small and large black holes if the charge
is less than its critical one. In higher dimensional () case, even
when the charge is absent, the small/large black hole phase transition can also
appear, the coefficients for the third () and/or the fourth ()
terms in the potential associated with graviton mass in the massive gravity can
play the same role as the charge does in the four dimensional case.Comment: Latex 19 pages with 8 figure
Estradiol regulates miR-135b and mismatch repair gene expressions via estrogen receptor-β in colorectal cells.
Estrogen has anti-colorectal cancer effects which are thought to be mediated by mismatch repair gene (MMR) activity. Estrogen receptor (ER) expression is associated with microRNA (miRNA) expression in ER-positive tumors. However, studies of direct link between estrogen (especially estradiol E2), miRNA expression, and MMR in colorectal cancer (CRC) have not been done. In this study, we first evaluated the effects of estradiol (E2) and its antagonist ICI182,780 on the expression of miRNAs (miR-31, miR-155 and miR-135b) using COLO205, SW480 and MCF-7 cell lines, followed by examining the association of tissue miRNA expression and serum E2 levels using samples collected from 18 colorectal cancer patients. E2 inhibited the expressions of miRNAs in COLO205 cells, which could be reversed by E2 antagonist ICI 182.780. The expression of miR-135b was inversely correlated with serum E2 level and ER-β mRNA expression in CRC patients' cancer tissues. There were significant correlations between serum E2 level and expression of ER-β, miR-135b, and MMR in colon cancer tissue. This study suggests that the effects of estrogen on MMR function may be related to regulating miRNA expression via ER-β, which may be the basis for the anti-cancer effect in colorectal cells
Efficient inhibition of hepatitis B virus replication by hepatitis delta virus ribozymes delivered by targeting retrovirus
<p>Abstract</p> <p>Background</p> <p>Hepatitis delta virus (HDV) ribozyme is an attractive molecular tool that can specifically recognize and catalyze the self-cleavage of the viral RNA phosphodiester backbone. However, a major obstacle in the medical application of the HDV ribozyme is the lack of specificity in the delivery of the ribozyme to defined target cells.</p> <p>Results</p> <p>The objective of this study was to determine whether retroviral vectors can deliver the HDV ribozyme into the target cells and to elucidate whether HDV ribozyme plays a role in hepatitis B virus (HBV) replication. In our study, the transduction of helper-free pseudotyped retrovirus, which showed a broad host range, in human hepatoma cells was performed under 2 conditions, that is, in the presence of polymerized human serum albumin (pHSA) and in the absence of pHSA. The transduction ability in the presence of pHSA was higher than in the absence of pHSA. Moreover, HBsAg and HBeAg levels after transductions with pHSA were significantly lower than those in the absence of pHSA, thus indicating that the recombinant retrovirus had HBV-specific cleavage activity and targeted HepG2215 cells.</p> <p>Conclusions</p> <p>These data suggest that this system provides a new approach for targeting hepatocytes and has a great potential in gene therapy for HBV infection.</p
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Epithelium-Specific ETS (ESE)-1 upregulated GP73 expression in hepatocellular carcinoma cells
Background: Golgi protein-73 (GP73) is a Golgi transmembrane glycoprotein elevated in numerous liver diseases. Clinically, GP73 is strongly elevated in the serum of HCC patients and is thus regarded as a novel potential biomarker for HCC. However, the mechanism leading to GP73 dysregulation in liver diseases remains unknown. Results: This study determined that epithelium-specific ETS (ESE)-1, an epithelium-specific transcription factor, and GP73 expressions were induced by IL-1β stimulation in vitro, and both were triggered during liver inflammation in vivo. In hepatocellular carcinoma cells, the overexpression of ESE-1 induced GP73 expression, whereas its knock-down did the opposite. Mechanistically, ESE-1 activated GP73 expression by directly binding to its promoter. Conclusions: Our findings supported a novel paradigm for ESE-1 as a transcriptional mediator of GP73. This study provided a possible mechanism for GP73 upregulation in liver diseases. Electronic supplementary material The online version of this article (doi:10.1186/2045-3701-4-76) contains supplementary material, which is available to authorized users
Combined finite element and multi-body dynamics analysis of effects of hydraulic cylinder movement on ploughshare of horizontally reversible plough
Abstract: Hydraulic Cylinder (HC), one of the key components of Horizontally Reversible Plough (HRP), takes the responsibilities for the commuting soiltillage of HRP. The dynamic behaviors of HC surely affectthe tilling performances of HRP. Based on our previously related work, this paper further addresses the effects of HC movements during tillage on ploughshare, especially at share-point, of HRP. For HC, uniform motion was considered in this study. A combined finite element and multi-body dynamics analysis (MDA) was implemented to assess both tillage kinematics and kinetics of the ploughshare. These numerical predictions were primarily involved in five different HC movement velocities and two actual HRP tilling scenarios, respectively, where loading data due to the HC movements were obtained from an MDA and applied to load a finite element modal of the ploughshare. Our results show that the importance of performing MDA as a preliminary step FEA to obtain an insight into the actual stress and strain variations at the share-point. Our findings demonstrate that the different movements of HC have no adverse effects on the service life of the ploughshare though they result in the maximum stress and strain at the sharepoint during HRP tillage
Traditional Chinese Herb Combined with Surgery versus Surgery for Varicocele Infertility: A Systematic Review and Meta-Analysis
Objective. The objective of this study was to conduct a systematic review to assess the effectiveness and safety of traditional Chinese herb combined with surgery for male varicocele infertility compared to surgery. Methods. Randomized controlled trials (RCTs) data of traditional Chinese herbs combined with surgery for male varicocele fertility versus surgery were collected by searching the Cochrane Library, Embase, PubMed, and Chinese databases. The risk of bias was assessed using Cochrane Handbook. Study outcomes were presented as risk ratios (RRs) for dichotomous data. Results. Seventeen of 72 potentially relevant trials met the inclusion criteria. The methodological qualities of the RCTs were low. Compared with the surgery group, the traditional Chinese herb combined with surgery group had superiority in pregnancy rate at 3-month (RR=1.76, and P=0.008), 6-month (RR=1.58, and P=0.0005), and 2-year (RR=1.58, and P=0.0005) follow-ups. No RCT was found to describe the side effects. Conclusion. On considering the low methodological quality of RCTs, there was no enough evidence on traditional Chinese herb with surgery for male varicocele infertility, and more high-quality RCTs of large sample sizes are required
Identification of susceptibility genes in non-syndromic cleft lip with or without cleft palate using whole-exome sequencing
Background: Non-syndromic cleft lip with or without cleft palate (NSCL/P) is among the most common congenital malformations. The etiology of NSCL/P remains poorly characterized owing to its complex genetic heterogeneity. The objective of this study was to identify genetic variants that increase susceptibility to NSCL/P.
Material and Methods: Whole-exome sequencing (WES) was performed in 8 fetuses with NSCL/P in China.
Bioinformatics analysis was performed using commercially available software. Variants detected by WES were
validated by Sanger sequencing.
Results: By filtering out synonymous variants in exons, we identified average 8575 nonsynonymous single nucleotide variants (SNVs). We subsequently compared the SNVs against public databases including NCBI dbSNP
build 135 and 1000 Genomes Project and obtained an average of 203 SNVs. Total 12 reported candidate genes
were verified by Sanger sequencing. Sanger sequencing also confirmed 16 novel SNVs shared by two or more
samples.
Conclusions: We have found and confirmed 16 susceptibility genes responsible for NSCL/P, which may play important role in the etiology of NSCL/P. The susceptibility genes identified in this study will not only be useful in
revealing the etiology of NSCL/P but also in diagnosis and treatment of the patients with NSCL/P
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