基于聚合回归的城市燃气用户用气量主要影响因素分析

本文以成都市WJ区城市燃气用户为研究对象,采用关联规则挖掘方法,挖掘用户用气量大小及四季波动情况与用户性质、气表类型、壁挂炉采暖使用情况等因素之间的关系。通过收集一定时期内的温度和用气量数据,采用聚合回归分析建立量化模型,同时评估模型表现和进行预测和分析。研究结果表明,温度是影响用户用气量的主要影响因素之一,建立的温度和用气量的量化关系模型能够较好地预测用气量的变化。

验潮站坐标时间序列特性分析

文中以298个验潮站作为研究对象,采用广义高斯-马尔科夫模型(GGM)、自回归滑动平均模型(ARMA)以及分形自回归聚合滑动平均模型(ARFIMA)三种模型,对验潮站坐标时间序列噪声模型特性及海平面变化趋势进行估计分析,并探讨了时间跨度对验潮站速度估计的影响.实验结果表明:验潮站坐标时间序列主要呈现为ARFIMA(1,0)、ARFIMA(2,2)、ARMA(1,0)噪声特性;验潮站速度估计结果表明64.77%的站点速度值所处区间为0~4 mm/a,平均海平面速度为1.25 mm/a,整体处于上升趋势.随着时间跨度的增加,验潮站坐标序列速度不确定度逐渐由发散趋于收敛,大于110 a的时间跨度有助于获取稳健的验潮站速度估计值.

Independent and combined effects of environmental factors and miR-126, miR-143, and miR-145 on the risk of coronary heart disease

Objective To evaluate the effects of environmental factors and microRNAs （miRNAs） （miR-126, miR-143, and miR-145） on the risk of coronary heart disease （CHD）. Methods A frequency-matched case-control study （450 patients, 450 controls） was conducted from April 2014 to December 2016 in Fuzhou City, China. Environmental factors were investigated using a self-administered questionnaire, and the expression levels of miR-126, rniR-143, and miR-145 were determined by quantitative real-time Polymerase Chain Reaction （PCR） in pe- ripheral blood mononuclear cells. Unconditional logistic regression models were used for statistical evaluation. Results Alcohol consumption, high-salt diets, high-intensity work, and lack of physical activity were significantly associated with increased CHD risk, whereas light diet was significantly associated with decreased risk. MiR-126, miR-143, and miR-145 were highly expressed in the CHD group compared with the control group. After adjustment for other environmental factors, unconditional logistic regression results revealed that miR-126, miR-143, and depression were the independent risk factors of CHD, and light diet was the independent protective factor of CHD. Conclusions Our data suggest that a family history of CHD, anxiety, and alcohol consumption was significantly associated with increased CHD risk, whereas light diet was significantly associated with decreased risk. Furthermore, miR-126 and miR-143 in combination with several risk factors, could play a joint role in the development of CHD. Therefore, it is necessary to manage patients with CHD in all directions and multiple level.

XAF1 is frequently methylated in human esophageal cancer

AIM： To explore epigenetic changes in the gene encod- ing X chromosome-linked inhibitor of apoptosis-associ- ated factor 1 （XAF1） during esophageal carcinogenesis. METHODS： Methylation status of XAF1 was detected by methylation-specific polymerase chain reaction （MSP） in four esophageal cancer cell lines （KYSE30, KYSE70, BICl and partially methylated in TE3 cell lines）, nine cases of normal mucosa, 72 cases of pri- mary esophageal cancer and matched adjacent tissue. XAF1 expression was examined by semi-quantitative reverse transcriptional polymerase chain reaction and Western blotting before and after treatment with 5-aza- deoxycytidine （5-aza-dc）, a demethylating agent. To investigate the correlation of XAF1 expression and methylation status in primary esophageal cancer, immu- nohistochemistry for XAF1 expression was performed in 32 cases of esophageal cancer and matched adjacent tissue. The association of methylation status and clini-copathological data was analyzed by logistic regression. RESULTS： MSP results were as follows： loss of XAF1 expression was found in three of four esophageal cell lines with promoter region hypermethylation （com- pletely methylated in KYSE30, KYSE70 and BIC1 cell lines and partially in TE3 cells）; all nine cases of normal esophageal mucosa were unmethylated; and 54/72 （75.00%） samples from patients with esophageal can- cer were methylated, and 25/72 （34.70%） matched adjacent tissues were methylated （75.00% vs 34,70%, z2 = 23.5840, P = 0.000）. mRNA level of XAF1 mea- sured with semi-quantitative reverse transcription poly- merase chain reaction was detectable only in TE3 cells, and no expression was detected in KYSE30, KYSE70 or BIC1 cells. Protein expression was not observed in KYSE30 cells by Western blotting before treatment with 5-aza-dc. After treatment, mRNA level of XAF1 was detectable in KYSE30, KYSE70 and BIC1 cells. Protein expression was detected in KYSE30 after treatment with 5-aza-dc. Immunohistochemistry was performed on 32 cases of esophageal cancer and adjacent tissue, and demonstrated XAF1 in the nucleus and cytoplasm. XAF1 staining was found in 20/32 samples of adjacent normal tissue but was present in only 8/32 samples of esophageal cancer tissue （Z2= 9.143, P = 0.002）. XAF1 expression was decreased in cancer samples compared with adjacent tissues. In 32 cases of esophageal can- cer, 24/32 samples were methylated, and 8/32 esopha- geal cancer tissues were unmethylated. XAF1 staining was found in 6/8 samples of unmethylated esophageal cancer and 2/24 samples of methylated esophageal cancer tissue. XAF1 staining was inversely correlated with XAF1 promoter region methylation （Fisher＇s exact test, P = 0.004）. Regarding methylation status and clinicopathological data, no significant differences were found in sex, age, tumor size, tumor stage, or metas- tasis with respect to methylation of XAF1 for the 72 tis- sue samples from patients with esophageal cancer. CONCLUSION： XAF1 is frequently methylated in eso- phageal cancer, and XAF1 expression is regulated by promoter region hypermethylation.

Effects Analysis of Mg^2＋, dNTPs and Taq DNA Polymerase on SSR-PCR System of Pear

Effects of Mg^2＋, NTPs and Taq DNA polymerase in pear SSR-PCR system were analyzed by quadratic regressive orthogonal rotational combinational design. Results showed： absolute IOD （Integrated OD of each band） value of target band reduced with concentration rising of Mg^2＋ and Taq DNA polymerase, but heightened with concentration rising of dNTPs. The decay rate of absolute IOD value increased progressively with rising Mg^2＋ concentration, decreased gradually with rising Taq DNA polymerase concentration; the rising speed would be slower than the dNTPs increase. Absolute IOD value would reduce with concentration rising of dNTPs at a low level of Mg^2＋ concentration. Conversely it would rise with the increase of dNTPs while high Mg^2＋ concentration. Absolute IOD value would generally rise with concentration rising of Taq DNA polymerase while low Mg^2＋ concentration. On the contrary it would reduce with concentration rising of Taq DNA polymerase while high Mg^2＋ concentration.

Prediction of thermal conductivity of polymer-based composites by using support vector regression

Support vector regression (SVR) combined with particle swarm optimization (PSO) for its parameter optimization, was proposed to establish a model to predict the thermal conductivity of polymer-based composites under different mass fractions of fillers (mass fraction of polyethylene (PE) and mass fraction of polystyrene (PS)). The prediction performance of SVR was compared with those of other two theoretical models of spherical packing and flake packing. The result demonstrated that the estimated errors by leave-one-out cross validation (LOOCV) test of SVR models, such as mean absolute error (MAE) and mean absolute percentage error (MAPE), all are smaller than those achieved by the two theoretical models via applying identical samples. It is revealed that the generalization ability of SVR model is superior to those of the two theoretical models. This study suggests that SVR can be used as a powerful approach to foresee the thermal property of polymer-based composites under different mass fractions of polyethylene and polystyrene fillers.