排序方式: 共有32条查询结果,搜索用时 15 毫秒
1.
2.
Touraj Mohammadpour Amir Massoud Bidgoli Rasul Enayatifar Hamid Haj Seyyed Javadi 《Genomics》2019,111(6):1902-1912
The ultimate goal of the Recommender System (RS) is to offer a proposal that is very close to the user's real opinion. Data clustering can be effective in increasing the accuracy of production proposals by the RS. In this paper, single-objective hybrid evolutionary approach is proposed for clustering items in the offline collaborative filtering RS. This method, after generating a population of randomized solutions, at each iteration, improves the population of solutions first by Genetic Algorithm (GA) and then by using the Gravitational Emulation Local Search (GELS) algorithm. Simulation results on standard datasets indicate that although the proposed hybrid meta-heuristic algorithm requires a relatively high run time, it can lead to more appropriate clustering of existing data and thus improvement of the Mean Absolute Error (MAE), Root Mean Square Error (RMSE) and Coverage criteria. 相似文献
3.
Hamedian AA Esteghamati A Noshad S Mozafari M Moin-Tavakkoli H Nakhjavani M Mahmoudi T Nikzamir M Safary R Nikzamir A 《Molecular biology reports》2012,39(5):6213-6218
Vascular endothelial growth factor (VEGF) has long been recognized as a hypotensive mediator. Little is known regarding the
contribution of polymorphisms in VEGF gene to essential hypertension (EH), however. We aimed to investigate the association
between +405 VEGF C/G single nucleotide polymorphism (SNP) and occurrence of EH in a sample of patients with diabetes. A study
population of 474 subjects with diabetes of which 45.6% (216) had EH was enrolled in this study. Interviews and physical examinations
were performed in a clinical setting. Subjects were matched in baseline anthropometric and biochemical characteristics except
for total cholesterol. Genotyping of +405 VEGF C/G (rs2010963) SNP was carried out using polymerase chain reaction–restriction
fragment length polymorphism. The allelic distribution of the sample did not violate Hardy–Weinberg equilibrium. Subjects
with EH had a higher frequency of G allele (P = 0.005). Additionally, those with EH had a significantly higher frequency of GG genotype (P = 0.015). In multivariate logistic regression models controlling for possible confounders, having GG against CC genotype
was associated with an odds ratio of 2.51 (95% CI: 1.44–4.38; P = 0.001). Moreover, presence of each G allele was linked to a 1.58-fold increase in risk of having EH (95% CI: 1.200–2.086;
P = 0.001). In conclusion, +405 VEGF C/G SNP is associated with EH in patients with diabetes, suggesting presence of G allele
and GG or CG genotype confer susceptibility towards EH. 相似文献
4.
Zahra Shokati Eshkiki Mohammad Hossein Ghahremani Parisa Shabani Sattar Gorgani Firuzjaee Asie Sadeghi Hossein Ghanbarian Reza Meshkani 《Molecular and cellular biochemistry》2017,425(1-2):95-102
Protein tyrosine phosphatase 1B (PTP1B) has been shown to regulate multiple cellular events such as differentiation, cell growth, and proliferation; however, the role of PTP1B in differentiation of embryonic stem (ES) cells into cardiomyocytes remains unexplored. In the present study, we investigated the effects of PTP1B inhibition on differentiation of ES cells into cardiomyocytes. PTP1B mRNA and protein levels were increased during the differentiation of ES cells into cardiomyocytes. Accordingly, a stable ES cell line expressing PTP1B shRNA was established. In vitro, the number and size of spontaneously beating embryoid bodies were significantly decreased in PTP1B-knockdown cells, compared with the control cells. Decreased expression of cardiac-specific markers Nkx2-5, MHC-α, cTnT, and CX43, as assessed by real-time PCR analysis, was further confirmed by immunocytochemistry of the markers. The results also showed that PTP1B inhibition induced apoptosis in both differentiated and undifferentiated ES cells, as presented by increasing the level of cleaved caspase-3, cytochrome C, and cleaved PARP. Further analyses revealed that PTP1B inhibition did not change proliferation and pluripotency of undifferentiated ES cells. Taken together, the data presented here suggest that PTP1B is essential for proper differentiation of ES cells into cardiomyocytes. 相似文献
5.
Epidemiological evidence suggests the protective effect of vitamin D against colorectal cancer (CRC) and the polymorphisms
in vitamin D receptor (VDR) gene may influence the development of CRC. In this study the possible association of VDR FokI
and BsmI gene polymorphisms with CRC risk was examined. A total of 904 subjects, including 452 cases with CRC and 452 controls
were enrolled in this study. All 904 subjects were genotyped for VDR FokI and BsmI gene polymorphisms by PCR-RFLP method.
We observed no significant difference in genotype and allele frequencies between the cases with CRC and controls for the both
FokI and BsmI polymorphisms either before or after adjustment for confounding factors including age, BMI, sex, and smoking
status. Furthermore, no evidence for effect modification of the association VDR gene FokI and BsmI variants and CRC by BMI,
sex, or tumor site was observed. In addition, there was no significant difference in genotype and allele frequencies between
the normal weight (BMI <25 kg/m2) cases with CRC and overweight/obese (BMI ≥25 kg/m2) cases with CRC for the two SNPs. Our results do not lend support to the hypothesis that VDR gene FokI and BsmI polymorphisms
are associated with the risk of CRC. However, further studies are required to confirm this finding. 相似文献
6.
Nader Mansour Samaei Yaghoub Yazdani Reza Alizadeh-Navaei Hossein Azadeh Touraj Farazmandfar 《Journal of biomedical science》2014,21(1):73
Background
Aberrant DNA methylation as the most important reason making epigenetic silencing of genes is a main mechanism of gene inactivation in patients with colorectal cancer. In this study, we decided to identify promoter methylation status of ten genes encoding WNT negative regulators, and measure the expression of DNMT1 enzyme in colorectal cancer samples.Results
Aberrant methylation of APC gene was statistically significant associated with age over 50 (p = 0.017), DDK3 with male (p < 0.0001), SFRP4, WIF1, and WNT5a with increasing tumor stage (p = 0.004, p = 0.029, and p = 0.004), SFRP4 and WIF1 with tumor differentiation (p = 0.009 and p = 0.031) and SFRP2 and SFRP5 with histological type (p = 0.001 and p = 0.025). The increasing number of methylated genes correlated with the expression levels of the DNMT1 mRNA.Conclusions
The rate of gene promoter methylation of WNT pathway regulators is high in colorectal cancer cells. Hyper-methylation is associated with increased expression of the DNMT1 enzyme. 相似文献7.
Touraj Rahimi Ali Niazi Tahereh Deihimi Seyed Mohsen Taghavi Shahab Ayatollahi Esmaeil Ebrahimie 《Functional & integrative genomics》2018,18(5):533-543
One of the main challenges in elimination of oil contamination from polluted environments is improvement of biodegradation by highly efficient microorganisms. Bacillus subtilis MJ01 has been evaluated as a new resource for producing biosurfactant compounds. This bacterium, which produces surfactin, is able to enhance bio-accessibility to oil hydrocarbons in contaminated soils. The genome of B. subtilis MJ01 was sequenced and assembled by PacBio RS sequencing technology. One big contig with a length of 4,108,293 bp without any gap was assembled. Genome annotation and prediction of gene showed that MJ01 genome is very similar to B. subtilis spizizenii TU-B-10 (95% similarity). The comparison and analysis of orthologous genes carried out between B. subtilis MJ01, reference strain B. subtilis subsp. subtilis str. 168, and close relative spizizenii TU-B-10 by microscope platform and various bioinformatics tools. More than 88% of 4269 predicted coding sequences in MJ01 had at least one similar sequence in genome of reference strain and spizizenii TU-B-10. Despite this high similarity, some differences were detected among encoding sequences of non-ribosome protein and bacteriocins in MJ01 and spizizenii TU-B-10. MJ01 has unique nucleotide sequences and a novel predicted lasso-peptide bacteriocin; it also has not any similar nucleotide sequence in non-redundant nucleotide data base. 相似文献
8.
Rahul Bohra Wenzel Sch?ning Jelena Klawitter Nina Brunner Volker Schmitz Touraj Shokati Ryan Lawrence Maria Fernanda Arbelaez Bj?rn Schniedewind Uwe Christians Jost Klawitter 《PloS one》2012,7(10)
Enhancement of calcineurin inhibitor nephrotoxicity by sirolimus (SRL) is limiting the clinical use of this drug combination. We compared the dose-dependent effects of the structurally related everolimus (EVL) and sirolimus (SRL) alone, and in combination with cyclosporine (CsA), on the rat kidney. Lewis rats were treated by oral gavage for 28 days using a checkerboard dosing format (0, 3.0, 6.0 and 10.0 CsA and 0, 0.5, 1.5 and 3.0 mg/kg/day SRL or EVL, n = 4/dose combination). After 28 days, oxidative stress, energy charge, kidney histologies, glomerular filtration rates, and concentrations of the immunosuppressants were measured along with 1H-magnetic resonance spectroscopy (MRS) and gas chromatography- mass spectrometry profiles of cellular metabolites in urine. The combination of CsA with SRL led to higher urinary glucose concentrations and decreased levels of urinary Krebs cycle metabolites when compared to controls, suggesting that CsA+SRL negatively impacted proximal tubule metabolism. Unsupervised principal component analysis of MRS spectra distinguished unique urine metabolite patterns of rats treated with CsA+SRL from those treated with CsA+EVL and the controls. SRL, but not EVL blood concentrations were inversely correlated with urine Krebs cycle metabolite concentrations. Interestingly, the higher the EVL concentration, the closer urine metabolite patterns resembled those of controls, while in contrast, the combination of the highest doses of CsA+SRL showed the most significant differences in metabolite patterns. Surprisingly in this rat model, EVL and SRL in combination with CsA had different effects on kidney biochemistry, suggesting that further exploration of EVL in combination with low dose calcineurin inhibitors may be of potential benefit. 相似文献
9.
Cell-free protein synthesis protocols for uniformly deuterated proteins typically yield low, non-uniform deuteration levels.
This paper introduces an E. coli cell-extract, D-S30, which enables efficient production of proteins with high deuteration levels for all non-labile hydrogen
atom positions. Potential applications of the new protocol may include production of proteins with selective isotope-labeling
of selected amino acid residues on a perdeuterated background for studies of enzyme active sites or for ligand screening in
drug discovery projects, as well as the synthesis of perdeuterated polypeptides for NMR spectroscopy with large supra-molecular
structures. As an illustration, it is demonstrated that the 800-kDa chaperonine GroEL synthesized with the D-S30 cell-free
system had a uniform deuteration level of about 95% and assembled into its biologically active oligomeric form. 相似文献
10.
Lang Q Cheng IF Wai CM Paszczynski A Crawford RL Barnes B Anderson TJ Wells R Corti G Allenbach L Erwin DP Assefi T Mojarradi M 《Analytical biochemistry》2002,301(2):225-234
A supercritical fluid extraction procedure and a chromatographic separation/detection method were developed for the detection of Earth-based microorganisms. After microbes in a sand or a soil sample were hydrolyzed in a diluted NH(4)OH/acetone solution, several redox compounds from bacteria could be effectively extracted with trimethylamine-modified supercritical CO(2) at 35 degrees C and 300 atm. These signature redox-active compounds were separated by a reversed-phase HPLC column in an ion-pair mode and then monitored with a diode array detector and an electrochemical detector. The analytical results demonstrated the feasibility of using the reported techniques to detect the chemical signature of life in barren desert sand samples. 相似文献