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In the mining process of the II1 coal seam at Zhaogu No. 2 coal mine, a method of stratified mining is employed, leaving relatively wide coal pillars in sections. To enhance the resource recovery rate, the mine carries out the cooperative mining of the sectional coal pillars and the lower layer coal seam. The 14,022 cooperative working face of fully-mechanized and fully-mechanized top-coal caving at Zhaogu No. 2 coal mine is taken as the research object. Through numerical simulation, theoretical calculations, and on-site industrial trials, a comprehensive analysis of the overburden structural characteristics and the support adaptability at the working face is conducted. It is clarified that a stress arch bearing structure can be formed above the sectional coal pillars during cooperative mining, and this structure is controlled by key strata. The formation of a stress arch bearing structure in the overburden above the sectional coal pillars provides protection for the underlying mining area. A formula for calculating the working resistance of hydraulic supports under the stress arch in sectional coal pillar is derived. Based on these results, the working resistance of hydraulic supports in the coal pillar area is calculated and selected. Field application shows that the working resistance of the support is 10,000 kN in the fully-mechanized top-coal caving working face, and is 9000 kN in fully-mechanized working face, meeting the support requirements and ensuring safe mining at the working face. This study provides a valuable engineering reference for achieving cooperative mining of abandoned sectional coal pillars and lower layer coal seam in stratified mining method.
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Objective:To study the genetic variation and distribution characteristics of thalassemia in people of childbearing age in Hubei Province, and to provide clinical basis for the local government decision-making departments to formulate and promote appropriate policies for prevention and control of thalassemia.Methods:Venous blood samples were collected from 44 849 people of childbearing age in hospitals in Hubei Province from May 13, 2019 to August 17, 2021. PCR-flow fluorescence hybridization and PCR+diversion hybridization were used to screen thalassemia genes. Spouses of those who tested positive were also tested for thalassemia genes. When both spouses carried the same type of thalassemia gene, the amniotic fluid of pregnant women was extracted for prenatal diagnosis and followed up.Results:Among the 44 849 people of childbearing age, 2 286 cases were diagnosed as thalassemia gene carriers through genetic testing, and the total detection rate was 5.10% (2 286/44 849). Among them, 1 488 cases were diagnosed as α-thalassemia, and the detection rate was 3.32% (1 488/44 849); 767 cases were diagnosed as β-thalassemia, and the detection rate was 1.71% (767/44 849); 31 cases were diagnosed as α-thalassemia combined with β-thalassemia, and the detection rate was 0.07% (31/44 849). The top three genotypes of α-thalassemia were -α 3.7/αα, -- SEA/αα, and -α 4.2/αα, accounting for 58.06% (864/1 488), 26.14% (389/1 488), and8.74% (130/1 488), respectively. The top three genotypes of β-thalassemia were β IVS-Ⅱ-654/β N, β CD41-42/β N, and β CD17/β N, accounting for 41.72% (320/767), 21.25% (163/767), and 16.04% (123/767), respectively. The main genotypes of α-thalassemia combined with β-thalassemia were -α 3.7/αα complex β IVS-Ⅱ-654/β N and -α 3.7/αα complex β CD41-42/β N, accounting for 29.03% (9/31) and 16.13% (5/31), respectively. A total of 59 people of childbearing age were conducted prenatal diagnosis, among fetus, there were 4 cases of severe thalassemia (2 cases of severe α-thalassemia, 2 cases of severe β-thalassemia), 5 cases of intermediate α-thalassemia, 5 cases of intermediate or severe β-thalassemia, 19 cases of mild thalassemia (8 cases of mild α-thalassemia, 11 cases of mild β-thalassemia), 13 cases of stationary α-thalassemia, and 1 case of stationary α-thalassemia combined with mild β-thalassemia, there were 12 cases without α-thalassemia or β-thalassemia genes. After follow-up, 4 cases of severe thalassemia, 2 cases of intermediate α-thalassemia, and 5 cases of intermediate or severe β-thalassemia were terminated pregnancy by the joint decision of both parents. Conclusions:In Hubei Province, the detection rate of thalassemia is high, and α-thalassemia is the main mutation type. The combination of thalassemia gene screening and prenatal diagnosis is of great significance in reducing the birth rate of children with thalassemia.
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In order to compare the setting of difference coefficients in DRG point payment in different cities in Zhejiang province, the implementation rules of DRG point payment issued by 11 cities in Zhejiang province were comprehensively analyzed. It was found that the difference coefficients in different cities could be divided into three categories, including hospital coefficients alone, hospital coefficients and grade coefficients weighted, and weighted by hospital coefficients, grade coefficients, personal burden levels, case mix indexes, and head-to-time ratio. Its setting differences included four aspects: connotation composition, weight distribution, threshold value, and classification of medical institutions. The authors suggested that the adjustment cycle should be set scientifically to dynamically adjust the difference coefficient, and the scientific setting of the difference coefficient should be promoted through provincial coordination.
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Objective To analyze the secular trends of pancreatic cancer incidence and mortality in Changning district of Shanghai from 1974 to 2013. Methods We calculated the age-standardized rates of incidence and mortality and the average annual percent changes for pancreatic cancer using Segi's world standard population and the data from Shanghai Cancer Registry. Age-period-cohort model was constructed to further assess the effect of age, diagnosis period and birth cohort on the secular trends of pancreatic cancer incidence and mortality. Results During 1974-2013, the age-standardized incidence and mortality rates were 6.49/105 and 6.01/105 in male, 4.83/105 and 4.57/105 in female, respectively. The age-standardized incidence was increased by 0.8% per year in male during past 40 years, while there was no change in mortality. The age-standardized incidence and mortality rates were increased by 1.6% and 1.3% per year in female. After adjusting the effects of diagnosis period and birth cohort, the incidence and mortality rates of pancreatic cancer increased by about 11% every 5 years older in both male and female. Diagnosis period and birth cohort had no statistical impact on the incidence and mortality of pancreatic cancer. Conclusion The age-standardized incidence of pancreatic cancer shows significantly rising trends during 1974-2013 in both male and female in Changning district of Shanghai, as well as the age-standardized mortality in female. The incidence and mortality rates also increase with age.
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As the second most common cause of death in the world, cancer has become a persistent public health challenge. The incidence and mortality in different countries and regions or of multiple cancer types are significantly different, which is closely related to economic development level, lifestyle and environmental factors. A large number of epidemiological studies have focused on cancer burden, epidemic pattern, etiology and prevention, which is very important for the government to formulate cancer prevention policies based on medical evidence and protect population health. Therefore, based on the latest epidemiological publications, this paper reviews the incidence and mortality of cancer as well as the time trend in major countries and areas.
