Microseismic comprehensive evaluation method for coal burst: a case study in the Zhaolou Coal Mine.

To explore the multiparameter precursor characteristics of pre- and post-coal burst. Based on a coal burst of LW 1305 in the Zhaolou Coal Mine, an early warning method combining stress‒strain curve and microseismic multiparameter is proposed. The research results show that coal burst was induced by the intrinsic static high-stress concentration and the strong external impact loading generated by fracturing of the key stratum. The precursors mainly characterize the enhancement trend of the S value, the sudden and sharp increase in the A(t) value, the continuous and abnormal decrease in the b value, the increasing absolute value of Z sharply and larger than 2, the continuous and abnormal decrease in the Qt value, and the dominant frequency moving to the low-frequency band. Essentially, many micro-fissures inside the key stratum initiated, converged and connected to form macro-fractures, which was verified by the attenuation rate of the K value. Considering the time-varying effect of the overlying stratum movement, the curves of the six parameters agree well with those of stress vs. strain, which indicates that it is reasonable to take the observed zone as a whole system to investigate the variation in the multiple parameters and fracturing of the key stratum. The research results can be applied to the monitoring, early warning and control of coal burst so that effective safety measures can be taken in real time.

[Analysis of the correlation of prevalence in allergic rhinitis and other allergic diseases].

OBJECTIVE: To obtain the prevalence of allergic rhinitis (AR) in different regions of northern China, to analyze the correlation and interaction between AR and bronchial asthma (BA) or atopic dermatitis (AD), and to provide reference for the prevention and treatment of allergic diseases such as AR. METHODS: To obtain the indexes including age, occupation, atopic physical fitness, smoking, alcohol, lifestyle and so on. To explore the correlation between AR and BA or AD. From April 2007 to May 2010, the serum specific IgE (sIgE) was investigated in different regions (rural areas of Qingxian, Hebei; coastal fishing village of Bohai Bay, Huanghua; area of Wuling Mountain, Chengde; urban areas of Tianjin) by randomly multi-stage and cluster sampling, with total population of 1524. RESULTS: The prevalence of AR, BA and AD were 9.1%, 5.4% and 6.0%. The prevalence of BA and AD were 30.9% and 29.5% in AR patients, but were 2.9% and 3.7% in non-AR, and the differences were of statistical significance (χ(2) values were 192.97 and 148.40, respectively, all P < 0.01). The risk of people with BA suffering from AR was as 8.619 times as those free from BA, the risk of people with AD suffering from AR was as 1.817 times as those free from AD and, the risk of workers suffering from AR was as 2.320 times as farmers in terms of working factor by analysis of Logistic regression for AR and BA, AD, age, occupation, atopic physical fitness and other factors. CONCLUSIONS: The prevalence of AR are correlated with BA and AD. It is greater between BA and AR than AD and AR in the strength of correlation.

[Research on prevalence and related factors in allergic rhinitis].

OBJECTIVE: To obtain the prevalence and related factors in allergic rhinitis (AR) and other allergic diseases in rural area in China through epidemiological investigation with large sample and multi-faceted survey data. METHODS: Face to face survey was conducted in different regions (rural areas of Cangzhou, Hebei, coastal fishing village of Bohai Bay, area of Wuling Mountain, Chengde, urban areas of Tianjin) from April 2007 to May 2009. In the same time, serum specific IgE (sIgE) was detected in the digits of every 0, 1or 5 in them. SPSS 13.0 software was used to analyze the data. RESULTS: Five thousand and ten cases were investigated. There were 823 cases with the symptoms or signs of AR (16.4%). Four hundred and two cases were found to have positive serum sIgE antibody in 1576 detected cases (25.5%). One hundred and fourty-six cases with nasal allergic symptoms or signs were diagnosed as AR. The incidence of AR was 9.3% (146/1576). The occurrence of allergic symptoms or signs had a significant statistical difference with factors such as age, occupation, atopic constitution (χ(2) value were 7.96, 9.73, 16.53, 8.95 respectively, all P < 0.05), and it was closely related to lower respiratory tract allergies (ß = 2.544, P < 0.01). The most common allergens were dog and cat epithelium in rural areas and dust mites in city. CONCLUSIONS: The incidence of AR is higher whether in urban or rural areas, it should be taken seriously as the impact on human health. The occurrence is closely related to physical characteristics and environmental factors.