544 research outputs found
Reconstruction of relativistic modified Newtonian dynamics for various cosmological scenarios
In this paper, we present several explicit reconstructions for a novel
relativistic theory of modified Newtonian dynamics (RMOND) derived from the
background of Friedmann-Lematre-Robertson-Walker cosmological
evolution. It is shown that the Einstein-Hilbert Lagrangian with a positive
cosmological constant is the only Lagrangian capable of accurately replicating
the exact expansion history of the cold dark matter (CDM)
universe filled solely with dust-like matter and the only way to achieve this
expansion history for the RMOND theory is to introduce additional degrees of
freedom to the matter sectors. Besides, we find that the CDM-era also
can be replicated without any real matter field within the framework of the
RMOND theory and the cosmic evolution exhibited by both the power-law and
de-Sitter solutions also can be obtained
Genetic relationships among twelve Chinese indigenous goat populations based on microsatellite analysis
Twelve Chinese indigenous goat populations were genotyped for twenty-six microsatellite markers recommended by the EU Sheep and Goat Biodiversity Project. A total of 452 goats were tested. Seventeen of the 26 microsatellite markers used in this analysis had four or more alleles. The mean expected heterozygosity and the mean observed heterozygosity for the population varied from 0.611 to 0.784 and 0.602 to 0.783 respectively. The mean FST (0.105) demonstrated that about 89.5% of the total genetic variation was due to the genetic differentiation within each population. A phylogenetic tree based on the Nei (1978) standard genetic distance displayed a remarkable degree of consistency with their different geographical origins and their presumed migration throughout China. The correspondence analysis did not only distinguish population groups, but also confirmed the above results, classifying the important populations contributing to diversity. Additionally, some specific alleles were shown to be important in the construction of the population structure. The study analyzed the recent origins of these populations and contributed to the knowledge and genetic characterization of Chinese indigenous goat populations. In addition, the seventeen microsatellites recommended by the EU Sheep and Goat Biodiversity Project proved to be useful for the biodiversity studies in goat breeds
Alterations in microRNA expression profiles in inflamed and non-inflamed ascending colon mucosae of patients with active Crohn's disease
Background and aims
The miRNA expression profiles of the terminal ileum, sigmoid colon, and rectal mucosa of adult patients with active Crohn';s disease (CD) have been previously reported. The purpose of this study was to identify dysregulated miRNAs in the mucosa of the ascending colon.
Methods
Biopsy tissue samples were taken from the mucosae of inflammatory (iCD) or non-inflammatory (niCD) areas of the ascending colons of adult patients with active CD. miRNA and mRNA expression profiles were detected using microarray analyses. miRNAs and mRNAs demonstrating significant differences were validated via quantitative real-time PCR (qRT-PCR). Luciferase reporter genes were used to measure two miRNAs inhibition of potential target genes in human 293T cells in vitro.
Results
Compared with the HC group, the ascending colon miRNA expression profiles revealed that 43 miRNAs were significantly up-regulated and 35 were down-regulated in the iCD group. The mRNA expression profiles indicated that 3,370 transcripts were significantly differentially expressed in the ascending colon, with 2169 up-regulated and 1201 down-regulated mRNAs in the iCD group, and only 20 miRNAs demonstrated significant differential expression in the niCD group. In contrast, nearly 100 miRNAs significantly varied between the iCD and niCD groups. Finally, luciferase reporter gene assays showed that hsa-miR-16-1 directly regulated the human C10orf54 gene and that they were negatively correlated.
Conclusions
Our results indicated that the differentially expressed miRNAs and mRNAs were related to immune inflammation and intestinal flora. The data provide preliminary evidence that the occurrence of CD involves the inhibition of C10orf54 expression by hsa-miR-16-1
Isolation and characterization of drought-responsive genes from peanut roots by suppression subtractive hybridization
Background: Peanut ( Arachis hypogaea L.) is an important economic
and oilseed crop. Long-term rainless conditions and seasonal droughts
can limit peanut yields and were conducive to preharvest aflatoxin
contamination. To elucidate the molecular mechanisms by which peanut
responds and adapts to water limited conditions, we isolated and
characterized several drought-induced genes from peanut roots using a
suppression subtractive hybridization (SSH) technique. Results: RNA was
extracted frompeanut roots subjected to a water stress treatment (45%
field capacity) and from control plants (75% field capacity), and used
to generate an SSH cDNA library. A total of 111 non-redundant sequences
were obtained, with 80 unique transcripts showing homology to known
genes and 31 clones with no similarity to either hypothetical or known
proteins. GO and KEGG analyses of these differentially expressed ESTs
indicated that drought-related responses in peanut could mainly be
attributed to genes involved in cellular structure and metabolism. In
addition, we examined the expression patterns of seven differentially
expressed candidate genes using real-time reverse transcription-PCR
(qRT-PCR) and confirmed that all were up-regulated in roots in response
to drought stress, but to differing extents. Conclusions: We
successfully constructed an SSH cDNA library in peanut roots and
identified several drought-related genes. Our results serve as a
foundation for future studies into the elucidation of the drought
stress response mechanisms of peanut
92-Gene Molecular Profiling in Identification of Cancer Origin: A Retrospective Study in Chinese Population and Performance within Different Subgroups
BACKGROUND: After cancer diagnosis, therapy for the patient is largely dependent on the tumor origin, especially when a metastatic tumor is being treated. However, cases such as untypical metastasis, poorly differentiated tumors or even a limited number of tumor cells may lead to challenges in identifying the origin. Moreover, approximately 3% to 5% of total solid tumor patients will not have to have their tumor origin identified in their lifetime. The THEROS CancerTYPE ID® is designed for identifying the tumor origin with an objective, rapid and standardized procedure. METHODOLOGY AND PRINCIPAL FINDINGS: This is a blinded retrospective study to evaluate performance of the THEROS CancerTYPE ID® in a Chinese population. In total, 184 formalin-fixed paraffin-embedded (FFPE) samples of 23 tumor origins were collected from the tissue bank of Fudan University Shanghai Cancer Center (FDUSCC). A standard tumor cell enrichment process was used, and the prediction results were compared with reference diagnosis, which was confirmed by two experienced pathologists at FDUSCC. All of the 184 samples were successfully analyzed, and no tumor specimens were excluded because of sample quality issues. In total, 151 samples were correctly predicted. The agreement rate was 82.1%. A Pearson Chi-square test shows that there is no difference between this study and the previous evaluation test performed by bioTheranostics Inc. No statistically significant decrease was observed in either the metastasis group or tumors with high grades. CONCLUSIONS: A comparable result with previous work was obtained. Specifically, specimens with a high probability score (>0.85) have a high chance (agreement rate = 95%) of being correctly predicted. No performance difference was observed between primary and metastatic specimens, and no difference was observed among three tumor grades. The use of laser capture micro-dissection (LCM) makes the THEROS CancerTYPE ID® accessible to almost all of the cancer patients with different tumor statuses
Targeting the IL-6 Dependent Phenotype Can Identify Novel Therapies for Cholangiocarcinoma
The need for new therapies for cholangiocarcinoma is highlighted by their poor prognosis and refractoriness to chemotherapy. Increased production of Interleukin-6 promotes cholangiocarcinoma growth and contributes to chemoresistance by activating cell survival mechanisms. We sought to identify biologically active compounds capable of ameliorating the phenotypic effects of IL-6 expression and to explore their potential therapeutic use for cholangiocarcinoma.A genomic signature associated with Interleukin-6 expression in Mz-ChA-1 human malignant cholangiocytes was derived. Computational bioinformatics analysis was performed to identify compounds that induced inverse gene changes to the signature. The effect of these compounds on cholangiocarcinoma growth was then experimentally verified in vitro and in vivo. Interactions with other therapeutic agents were evaluated using median effects analysis.A group of structurally related compounds, nitrendipine, nifedipine and felodipine was identified. All three compounds were cytotoxic to Mz-ChA-1 cells with an IC50 for felodipine of 26 µM, nitrendipine, 44 µM and nifedipine, 15 µM. Similar results were observed in KMCH-1, CC-LP-1 and TFK-1 cholangiocarcinoma cell lines. At a fractional effect of 0.5, all three agents were synergistic with either camptothecin or gemcitabine in Mz-ChA-1 cells in vitro. Co-administration of felodipine and gemcitabine decreased the growth of Mz-ChA-1 cell xenografts in nude athymic mice.Computational bioinformatics analysis of phenotype-based genomic expression can be used to identify therapeutic agents. Using this drug discovery approach based on targeting a defined tumor associated phenotype, we identified compounds with the potential for therapeutic use in cholangiocarcinoma
An Updated Search of Steady TeV Ray Point Sources in Northern Hemisphere Using the Tibet Air Shower Array
Using the data taken from Tibet II High Density (HD) Array (1997
February-1999 September) and Tibet-III array (1999 November-2005 November), our
previous northern sky survey for TeV ray point sources has now been
updated by a factor of 2.8 improved statistics. From to
in declination (Dec) range, no new TeV ray point
sources with sufficiently high significance were identified while the
well-known Crab Nebula and Mrk421 remain to be the brightest TeV ray
sources within the field of view of the Tibet air shower array. Based on the
currently available data and at the 90% confidence level (C.L.), the flux upper
limits for different power law index assumption are re-derived, which are
approximately improved by 1.7 times as compared with our previous reported
limits.Comment: This paper has been accepted by hepn
Development, validation, and evaluation of a risk assessment tool for personalized screening of gastric cancer in Chinese populations
Background
Effective risk prediction models are lacking for personalized endoscopic screening of gastric cancer (GC). We aimed to develop, validate, and evaluate a questionnaire-based GC risk assessment tool for risk prediction and stratification in the Chinese population.
Methods
In this three-stage multicenter study, we first selected eligible variables by Cox regression models and constructed a GC risk score (GCRS) based on regression coefficients in 416,343 subjects (aged 40–75 years) from the China Kadoorie Biobank (CKB, development cohort). In the same age range, we validated the GCRS effectiveness in 13,982 subjects from another independent Changzhou cohort (validation cohort) as well as in 5348 subjects from an endoscopy screening program in Yangzhou. Finally, we categorized participants into low (bottom 20%), intermediate (20–80%), and high risk (top 20%) groups by the GCRS distribution in the development cohort.
Results
The GCRS using 11 questionnaire-based variables demonstrated a Harrell’s C-index of 0.754 (95% CI, 0.745–0.762) and 0.736 (95% CI, 0.710–0.761) in the two cohorts, respectively. In the validation cohort, the 10-year risk was 0.34%, 1.05%, and 4.32% for individuals with a low (≤ 13.6), intermediate (13.7~30.6), and high (≥ 30.7) GCRS, respectively. In the endoscopic screening program, the detection rate of GC varied from 0.00% in low-GCRS individuals, 0.27% with intermediate GCRS, to 2.59% with high GCRS. A proportion of 81.6% of all GC cases was identified from the high-GCRS group, which represented 28.9% of all the screened participants.
Conclusions
The GCRS can be an effective risk assessment tool for tailored endoscopic screening of GC in China. Risk Evaluation for Stomach Cancer by Yourself (RESCUE), an online tool was developed to aid the use of GCRS
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