Study of Reliability of Substation for Coal Mine Supervision System

AbstractThe sub-station has direct impact on the reliability of coal mine safety monitoring system reliability. The mine sub-station reliability of expected value and accelerated life test of the reliability value is given by setting the number of tests Censored Bayesian methods and Fixed Number Truncated of constant-stress accelerated methods on sub-station reliability research, and a sub-station with the voltage changes in the average life expectancy curves is simulationed. Through research we can see that the two methods to verify the reliability of the results of similar, and thus proved the scientific nature of the two methods

Effect of Metformin on Lactate Metabolism in Normal Hepatocytes under High Glucose Stress in Vitro

Objective To study the effect of metformin on lactate metabolism in hepatocytes in vitro under high glucose stress. In vitro LO2 cells, liver cells were randomly divided into blank control group, 25 tendency/L glucose solution, 27 tendency/L glucose solution,29 tendency/L glucose solution, 31 tendency/L glucose solution, 33 tendency/L glucose solution,35 tendency/L glucose solution treatment group, the optimal concentration of 31 tendency after L, use 30 tendency for L metformin solution, and then divided into blank control group, the optimal concentration of glucose solution, normal liver cells + metformin solution normal liver cells. The optimal concentration of glucose solution normal liver cells + metformin solution respectively in the 12 h, 24 h,48 h on cell count plate to calculate the number of liver cells, and using lactic acid determination kit the optimal concentration of glucose solution + normal liver cells and normal liver cells + the optimal concentration of glucose solution + metformin solution respectively in the 12 h, 24 h, 48 h of cell cultures of lactic acid value. There was no significant change in the lactic acid concentration but significant increase in the number of surviving hepatocytes in the highglycemic control group compared with that in the high-glycemic control group without metformin. Metformin has no significant effect on lactic acid metabolism of hepatocytes under high glucose stress in vitro, and has a protective effect on hepatocytes under high glucose stress. Based on this,it is preliminarily believed that metformin is not the direct factor leading to diabetic lactic acidosis

SUMOylation Represses Nanog Expression via Modulating Transcription Factors Oct4 and Sox2

Nanog is a pivotal transcription factor in embryonic stem (ES) cells and is essential for maintaining the pluripotency and self-renewal of ES cells. SUMOylation has been proved to regulate several stem cell markers' function, such as Oct4 and Sox2. Nanog is strictly regulated by Oct4/Sox2 heterodimer. However, the direct effects of SUMOylation on Nanog expression remain unclear. In this study, we reported that SUMOylation repressed Nanog expression. Depletion of Sumo1 or its conjugating enzyme Ubc9 increased the expression of Nanog, while high SUMOylation reduced its expression. Interestingly, we found that SUMOylation of Oct4 and Sox2 regulated Nanog in an opposing manner. SUMOylation of Oct4 enhanced Nanog expression, while SUMOylated Sox2 inhibited its expression. Moreover, SUMOylation of Oct4 by Pias2 or Sox2 by Pias3 impaired the interaction between Oct4 and Sox2. Taken together, these results indicate that SUMOylation has a negative effect on Nanog expression and provides new insights into the mechanism of SUMO modification involved in ES cells regulation

Nlrp2, a Maternal Effect Gene Required for Early Embryonic Development in the Mouse

Maternal effect genes encode proteins that are produced during oogenesis and play an essential role during early embryogenesis. Genetic ablation of such genes in oocytes can result in female subfertility or infertility. Here we report a newly identified maternal effect gene, Nlrp2, which plays a role in early embryogenesis in the mouse. Nlrp2 mRNAs and their proteins (∼118 KDa) are expressed in oocytes and granulosa cells during folliculogenesis. The transcripts show a striking decline in early preimplantation embryos before zygotic genome activation, but the proteins remain present through to the blastocyst stage. Immunogold electron microscopy revealed that the NLRP2 protein is located in the cytoplasm, nucleus and close to nuclear pores in the oocytes, as well as in the surrounding granulosa cells. Using RNA interference, we knocked down Nlrp2 transcription specifically in mouse germinal vesicle oocytes. The knockdown oocytes could progress through the metaphase of meiosis I and emit the first polar body. However, the development of parthenogenetic embryos derived from Nlrp2 knockdown oocytes mainly blocked at the 2-cell stage. The maternal depletion of Nlrp2 in zygotes led to early embryonic arrest. In addition, overexpression of Nlrp2 in zygotes appears to lead to normal development, but increases blastomere apoptosis in blastocysts. These results provide the first evidence that Nlrp2 is a member of the mammalian maternal effect genes and required for early embryonic development in the mouse

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

A Restarted Large-Scale Spectral Clustering with Self-Guiding and Block Diagonal Representation

Spectral clustering is one of the most popular unsupervised machine learning methods. Constructing similarity matrix is crucial to this type of method. In most existing works, the similarity matrix is computed once for all or is updated alternatively. However, the former is difficult to reflect comprehensive relationships among data points, and the latter is time-consuming and is even infeasible for large-scale problems. In this work, we propose a restarted clustering framework with self-guiding and block diagonal representation. An advantage of the strategy is that some useful clustering information obtained from previous cycles could be preserved as much as possible. To the best of our knowledge, this is the first work that applies restarting strategy to spectral clustering. The key difference is that we reclassify the samples in each cycle of our method, while they are classified only once in existing methods. To further release the overhead, we introduce a block diagonal representation with Nystr\"{o}m approximation for constructing the similarity matrix. Theoretical results are established to show the rationality of inexact computations in spectral clustering. Comprehensive experiments are performed on some benchmark databases, which show the superiority of our proposed algorithms over many state-of-the-art algorithms for large-scale problems. Specifically, our framework has a potential boost for clustering algorithms and works well even using an initial guess chosen randomly.Comment: 36 page

The Reliability Consideration of Coal Mine Safety Production Monitoring System Network

AbstractThis paper introduces membership cloud function and membership cloud generator, then establishes membership cloud function model which is fit for mine. With the application of the model through simulation, the reliability of ring network, tree network and star network in mine is analyzed. We could know that ring network which has the maximum reliability but poor fault resistance ability costs for not all links and nodes could use double road and it is not suitable for mine roadway. Tree network and star network, whose reliability are poor than double ring network's, are more suitable for mine roadway and have high cost performance, so they are more suitable for application in mine