Search

Based on the mining practice in an extremely close coal seam, theoretical analysis was conducted on the vertical stress distribution of the floor strata under a large coal pillar. The vertical stress distribution regulation of a No. 5 coal seam was revealed. To obtain the optimum position of the roadway that bears the supporting pressure of a large coal pillar, numerical modeling was applied to analyze the relation among the stress distribution of the roadway surrounding the rock that bears the supporting pressure of a large coal pillar, the plastic zone distribution of the roadway surrounding the rock, the surrounding rock deformation, and the roadway layout position. The theoretical calculation results of the stress value, stress variation rate, and influencing range of the stress influencing angle showed that the reasonable malposition of the No. 5 coal seam roadway was an inner malposition of 4 m. The mining practice showed the following: the layout of No. 25301 panel belt roadway at the position of the inner malposition of 4 m was reasonable, the roadway support performance was favourable without deformation, and ground pressure was not obvious. The research achievement of this study is the provision of a reference for roadway layouts under similar conditions.

Gene expression is an inherently noisy process due to low copy numbers of mRNA or protein. The involved reaction events may happen in a Markov fashion but also in a non-Markov manner, depending on waiting-time distributions for the occurrence of reaction events. In recent years, many mechanistic models of stochastic gene expression have been developed to forecast fluctuations in mRNA or protein levels. Here we discus commonalities between these models as well as their extensions from Markov to non-Markov models, focusing on the contributions of noisy sources to the protein level. We derive a useful formula for the protein noise quantified by the ratio of the variance over the squared mean. This formula, expressed in terms of the frequencies of the probabilistic events, can be used in the fast evaluation of fluctuations in the protein abundance. Although the detail of the formula may vary from gene to gene, it highlights sources of the protein noise, which can be decomposed into two parts: spontaneous fluctuations resulting from the birth and death of the protein and forced fluctuations originated from switching between the promoter states.

Objective: To study the relationship between familial clustering of hepatocellular carcinoma (HCC) and the polymorphism of cytochrome P450 2El gene (CYP2E1) as well as of other relevant risk factors to the cancer., Methods: Peripheral blood samples were collected from 91 members of 10 HCC clustering families and 102 of 10 control families, among Zhuang population, in Guangxi. The area had been with high incidence rate of HCC. Genotypes and allele frequencies of CYP2E1 Rsa I site were determined by polymerase chain reaction, combined with restriction fragment length polymorphism method (PCR-RFLP). Serum HBsAg was tested by means of ELISA. Data on relevant risk factors of the cancer were collected as well, through a unique questionnaire., Results: Frequencies of c1/c1 and c1/c2 genetypes of CYP2E1 Rsa I site were 63.7% and 36.3%, respectively, in the members of families with cancer clustering phenomena. In the members of the control families, these two rates were 48.0% and 52.0%, respectively (OR = 1.901, 95% CI: 1.067-3.387). Difference of genotypes frequencies of CYP2E1 Rsa I site between the members in these two groups was statistically significant (chi2 = 4.797, P = 0.029). According to the results from non-condition logistic regression analysis, the major risk factors on familial clustering of HCC could be listed as: intake of corns, HBsAg carrying status and CYP2E1 c1/c1 genotype., Conclusion: The relationship seemed to exist between familial clustering of HCC and the frequencies of polymorphism of cytochrome P450 2E1 gene (CYP2E1). The frequencies of CYP2E1 Rsa I site were neither the only nor the major factor, causing the familial clustering phenomenon of cancer. More possible, it was the affect of syntheses with the involvement of multiple factors.

Objective: To study the epidemiological characteristics of liver diseases in a rural population in Southern Guangxi, China., Methods: The enzyme immunoassays was used to detect of HBsAg and AFP. AFP positive serum samples were further examined for concentration of AFP by using a radio immunoassays. Liver morphological changes were measured with ultrasonography of type B., Results: The positive rates of HBsAg in the studied population was 17.8% (2800/15,701). The prevalence rates of viral hepatitis B, cirrhosis, primary liver cancer, clonorchiasis, fatty liver disease, alcoholic liver disease were 1.1% (173/15,701), 0.4% (63/15,701), 299.3 per 100,000 (47/15,701), 6.6% (1036/15,701), 4.8% (754/15,701) and 0.3% (47/15,701), respectively. The positive rates of HBsAg and the prevalence rates of viral hepatitis B, cirrhosis, primary liver cancer, clonorchiasis, fatty liver disease in male were significantly higher as compared with those in female (5.98 < or = chi(2) < or = 394.78, P < 0.01). No difference was observed in the prevalence rates of liver cavernous hemangioma and hepatic cysts between male and female. The prevalence rates of intrahepatic bile duct stones was significantly higher in female than in male (chi(2) = 30.80, P < 0.01). The positive rates of HBsAg and the prevalence rates of viral hepatitis B and clonorchiasis were decreased with age. But the prevalence rates of cirrhosis, primary liver cancer, fatty liver disease, alcoholic liver disease, liver cavernous hemangioma, hepatic cysts and intrahepatic bile duct stones were increased with age., Conclusion: The rural areas in the southern Guangxi are high prevalence regions of liver illness, and the male resident are even at high risk.