Objective To assess the health risks of fluoride in drinking water in rural schools in drinking-water fluorosis areas in Shaanxi Province, and to provide a scientific basis for formulating measures to prevent fluoride and improve water quality. Methods The drinking water of rural schools in Guanzhong and northern Shaanxi Province was monitored from 2017 to 2020. The fluoride concentration was evaluated in accordance with the ^“Sanitary Standards for Drinking Water^” (GB5749-2006). The health risk assessment method recommended by USEPA was used to assess the health risk of rural students exposed to fluoride through drinking water in the two regions. Results A total of 2 826 water samples were monitored from 2017 to 2020. The overall compliance rate of fluoride in water quality was 92.29%, with an average concentration of 0.500 mg/L. The non-carcinogenic health risk of fluoride in drinking water in rural schools in drinking-water fluorosis areas was <1. There was no statistically significant difference in non-carcinogenic health risk of fluoride in water quality between different regions of the same age group (P > 0.05). In the same age group, the non-carcinogenic health risk of fluoride in groundwater was higher than that in surface water (P < 0.05). The order of non-carcinogenic health risk of fluoride in drinking water with different water treatment methods from high to low was disinfection only > sedimentation filtration > conventional treatment > untreated (P < 0.05). Conclusion The non-carcinogenic risk of oral intake of fluoride in drinking water from rural schools in drinking-water fluorosis areas in Shaanxi Province is still at an acceptable level. In the future, it is necessary to continue to promote comprehensive prevention and treatment measures focusing on water improvement and fluoride reduction.

Objective:To study the risk factors of complications after bowel resection for acute mesenteric ischemic disease.Methods:Retrospective case-control study was used to analyze the case data of 68 patients diagnosed with acute mesenteric ischemic disease (AMI) with bowel resection at the First Medical Center of the PLA General Hospital from January 2010 to January 2020, including 43 males and 25 females. The patients were divided into complication group ( n=21) and the non-complication group ( n=47) according to whether they had complications after surgery. The risk factors associated with the development of postoperative complications were analyzed by multivariate Logistic stepwise regression method to determine the risk factors with clinical significance. Measurement data with normal distribution were expressed as mean ± standard deviation ( ± s), and t-test was used for comparison between groups. Chi-square test was used for comparison between count data groups. Results:Univariate analysis showed that age >60 years, Marshall score≥2, type of resected bowel, pathology suggestive of irreversible transmural necrosis, length of ICU stay >6 d, length of mechanical ventilation >2 d, American Society of Anesthesiologists (ASA) classification, and preoperative procalcitonin≥2 ng/mL were the risk factors affecting the development of complications after bowel resection for acute mesenteric ischemic disease risk factors ( P<0.05). Multivariate Logistic regression analysis showed that age>60 years ( HR=12.364, 95% CI: 1.135-134.662, P=0.039) and preoperative procalcitonin ≥2 ng/mL ( HR=14.144, 95% CI: 1.280-156.303, P=0.031) were independent risk factors for the development of postoperative complications after AMI parallel bowel resection. Conclusion:The rate of complications after combined bowel resection for AMI is high. When patients are combined with age>60 years and preoperative procalcitonin≥2 ng/mL, preoperative prevention of postoperative complications should be emphasized to improve the prognosis of patients.

Objective:To explore the relationship between integrin ɑ3(ITGA3)expression and immune cell infiltration in colorectal cancer(CRC).Methods:Bioinformatic methods were used to analyze ITGA3 mRNA expression in pan-cancer and CRC tissues,as well as its associ-ation with CRC prognosis.The correlation between ITGA3 and tumor-infiltrating immune cells was also investigated.In total,233 cases of CRC diagnosed at Shanxi Provincial Cancer Hospital between January and December 2021 were included,and ITGA3,CD8,CD163,FOXP3,PD-L1,CTLA-4,and PD-1 expression in CRC tissues were determined by immunohistochemistry(IHC)to analyze the relationship between ITGA3 and infiltrating immune cells and immune checkpoints.Results:Bioinformatics analysis showed elevated ITGA3 mRNA levels in CRC.High ITGA3 expression was associated with PFS(P＜0.05).Univariate and multifactorial analyses showed that age and stage were significantly cor-related with prognosis(P＜0.05).In addition,ITGA3 upregulation was closely correlated with multiple immune cell infiltration levels in CRC.Furthermore,IHC results showed that ITGA3 expression in CRC tissues was significantly higher than that in adjacent normal tissues(P＜0.05).ITGA3 expression was associated with lymph node metastasis(P＜0.05)and correlated with the expression of immune markers,such as CD8+T-cells,PD-L1,and CTLA-4(P＜0.05).Conclusions:ITGA3 is highly expressed in CRC,which is closely related to immune cell infiltration and may regulate the tumor immune microenvironment,which provides a new idea for clinical treatment and a potential new independent predictive marker.

Objective: To investigate the status and influencing factors of health literacy of middle school students in Yinchuan City, to provide reference for health literacy improvement of middle school students in this region. Methods: Using stratified cluster sampling method, 2 003 middle school students from three districts of Yinchuan were investigated to complete the questionnaire survey.The survey included basic characteristics, health literacy and screen time status. Results: The total score of Chinese Adolescent Interactive Health Literacy Questionnaire was(101.3±17.5). The proportion of high, medium and low level of health literacy were 25.0%, 51.2% and 23.9% respectively;the proportion of long screen time exposure among middle school students was 52.5%. The health literacy level of junior middle school students, middle school students with father or mother education level of high school or above and appropriate screen time were higher than those of the corresponding group（χ 2=49.90，14.59，16.53，46.73，P<0.01）. Logistic regression analysis showed that education group, grade, father s or mother s education level and long screen time exposure were associated with middle school students health literacy level(P<0.05). Conclusion The health literacy level of middle school students in Yinchuan City needs to be further improved and targeted health education should be carried out from school, family and society.

Objective To understand the status and dynamic changes in the treatment of rural garbage and sewage in Shaanxi Province and provide the basis for relevant departments to formulate policies and measures. Methods Every year from 2016 to 2018, 600 administrative villages in 30 agricultural counties were randomly selected as monitoring points, and 3 000 households were selected as monitoring households. Monitoring data was obtained through data reading, interviews, and on-site observations. Results The three-year rural population coverage rate of the garbage treatment plant was 28.31%, 36.10%, 39.36%, respectively, and the sewage treatment plant coverage rate was 12.27%, 20.39%, 15.02%, respectively. The annual differences were statistically significant（χ²=23.24、22.42，P=0.00）. The proportion of monitoring points for the three-year unified collection of domestic garbage was 30.50%, 43.67%, 51.00%, respectively, and the percentage of monitoring points for incineration garbage was 16.67%, 15.00%, 8.33%, respectively, and the annual differences were statistically significant（χ²=53.25、20.19，P=0.00）. The proportion of domestic sewage discharge monitoring points through pipelines was 12.67%, 11.17%, 31.17%, respectively, and the proportion of monitoring points discharged into treatment plants was 4.33%, 6.00%, 15.17%, respectively, and the annual differences were both statistically significant（χ²=99.45、52.50，P=0.00）. Conclusion In recent years, the rural garbage and sewage treatment situation in Shaanxi Province had improved, but there was still much room for improvement. It is recommended to increase environmental protection publicity and government investment, strengthen daily supervision, pay equal attention to construction and management, control the random stacking and discharging of garbage and sewage, and enhance the disposal rate of garbage and sewage.

Objective: To understand the status and trend of heavy metal indicators of drinking water in rural schools in different regions of Shaanxi Province, so as to provide scientific basis for safety of drinking water in rural schools. Methods: In 2017-2019, 697 rural school water supply projects in Shaanxi Province were tested for heavy metal indicators in the peripheral water. According to the sanitary standard for drinking water (GB 5749—2006), five heavy metal indicators, including arsenic, cadmium, hexavalent chromium, lead and mercury, were analyzed and evaluated in different years and regions. Results: A total of 2 298 valid water samples were collected and analyzed in 3 years. Except that lead and mercury are all up to standard, the standard rates of other heavy metals such as arsenic, cadmium and hexavalent chromium were 98.83%, 99.91% and 96.95% respectively. Compared with the Northern Shaanxi plateau and Qinba mountain area, the standard rate of water arsenic in Guanzhong Plain was lower (χ2=5.67, 13.59,P<0.01). The standard rate of hexavalent chromium was the highest in Qinba mountain area, followed by Guanzhong Plain, and the lowest in Northern Shaanxi plateau (χ2=20.48, 17.05, 48.32, P<0.01). Two samples of cadmium exceeding standard were from the Northern Shaanxi plateau. Conclusion The heavy metal index of drinking water in rural schools in Shaanxi Province exceeds the standard, which has obvious regional characteristics. We should focus on the harm of arsenic, hexavalent chromium and other heavy metals to the health of students in the Northern Shaanxi plateau and Guanzhong Plain. Cadmium and mercury in drinking water in local areas should be paid continued attention. Safety of drinking water in schools should be ensured from the aspects of water source selection and water treatment technology.

Objective To analyze the change in trends and existing problems of the water quality testing capabilities of the Centers for Disease Control and Prevention (CDC) in different cities and counties (districts) in Shaanxi Province from 2017 to 2019, and to provide references for laboratory capacity building. Methods A unified questionnaire was developed to investigate the water quality testing ability of all CDCs in different regions of Shaanxi Province, and the data were reported through the ^“National Drinking Water Quality Inspection Information System^”. Results From 2017 to 2019, in the testing of conventional indicators, the average number detected by the municipal CDCs was 37, 37, and 38, respectively, and all of them passed the measurement certification/laboratory accreditation. The average number detected by the county (district) CDCs was 30, 29, and 30, respectively, and only 65.14% of the county (district) CDCs passed the measurement certification/laboratory accreditation. In the testing of unconventional indicators, the average detectable number by city-level CDCs was 3, 5, and 4, respectively, while the average detectable number by county (district)-level CDCs was at most 1 item. There was no statistically significant difference in the average detection ability of CDCs at the city and county (district) levels in different regions in the same year (P>0.05); there was no significant difference in the average detection ability of CDCs at the city and county (district) levels in the same region in different years (P>0.05). Conclusion There is no difference in the CDC water quality testing level in different regions of Shaanxi Province, and the testing capacity needs to be further improved. It is recommended that the government should increase funding for disease control institutions, optimize the allocation of equipment and strengthen the construction of professional teams.

Objective: To investigate and analyze the drinking water quality among rural primary and secondary schools in Guanzhong area in 2018, and to provide a basis for the targeted improvement of water supply facilities. Methods: Develop a questionnaire on the basic situation of centralized water supply in rural schools, according to the Standard Test Method for Drinking Water (GB/T 5750—2006) and the Sanitary Standard for Drinking Water (GB 5749—2006) for the rural school network in Guanzhong area. The peripheral water collection and testing carried out single factor and multifactor statistical analysis on the relationship between water quality influencing factors and water quality pass rate. Results: The total qualified rate of drinking water quality in rural schools in Guanzhong area was 59.1%. Univariate analysis showed that water quality rate was affected by four factors including water source type, engineering type, sanitation permit and disinfection equipment use, and the difference was statistically significant(P<0.05). Unconditional two-class logistic regression analysis showed that disinfection (OR=3.14), engineering type (OR=2.05), and sanitation permit (OR=1.99)(P<0.05) affected the water quality pass rate. Conclusion It is recommended to further strengthen the investment in the renovation of water supply for rural schools in Guanzhong area, and specifically strengthen water supply treatment and standard disinfection.

Objective: To understand the disinfection status and microbial pollution of water supply project in rural schools in Shaanxi Province in 2018, and to provide basis for improving drinking water quality in rural schools. Methods: Data of water quality of water supply project in rural schools of Shaanxi Province in 2018 was collected, and the disinfectant surplus and microbial index compliance rate were analyzed according to "Sanitary Standard for Drinking Water" (GB 5749-2006). Results: The overall compliance rate of microbial indicators of water supply projects in rural schools in Shaanxi Province was 68.09%, and that of groundwater microbial indicators(71.97%) was higher than that of surface water(61.42%)(χ2=15.68, P<0.01); The overall compliance rate of microbial indicators in flood season(71.85%) was higher than that in dry season(64.34%)(χ2=7.44, P<0.01); The rate of reaching the standard of disinfectant residue was 77.27%. The rate of reaching the standard of microbial index of water samples with disinfection measures was higher than that of water samples without disinfection measures (χ2=31.88, P<0.01), The rate of reaching the standard of microbial index of water samples with disinfectant residue(88.89%) was higher than that of water samples with disinfectant residue(44.44%)(χ2=12.28, P<0. 01). Conclusion The main cause of microbial contamination of drinking water in rural schools in Shaanxi Province is inadequate equipment of disinfection equipment in water supply projects or not being used as required. It is suggested that schools, education and health departments should take measures to strengthen supervision and management of water plants to ensure the normal use of disinfection equipment.

Objective: To understand the environmental sanitation situation of rural schools in different geographical areas of Shaanxi, and to provide scientific basis for improving hygiene and sanitation in Chinese rural schools. Methods: Each year during 2016 to 2018, 150 townships in 30 counties of rural areas were randomly selected in various districts and cities throughout the province. In each township one junior high school and one elementary school were randomly selected, and the data was obtained through resource access, interviews, and on-site observations. The data was statistically analyzed and evaluated according to the northern, central and southern regions. Results: The differences of drinking ways among students in the schools were of statistical significance(χ2=25.89,P<0.01). The major drinking water method of students in the monitoring schools of the three regions all was providing boiled water, accounting for 56.16%, 65.88%, 50.39%, all of which have direct drinking unboiled water phenomenon; The water supply method of the self-provided centralized water supply school is mainly precipitation filtration in the central and southern regions, accounting for 38.46%, 53.21%, and untreated in the northern region(60.61%); The differences of the proportions of having sanitary toilets, detached toilets in schools, having toilets in teaching buildings, and having toilets in dormitory buildings in three regions were of statistical significance(χ2=32.04, 12.73, 20.78, 33.11, P<0.01) The proportion of schools with squat toilets in men’s toilets was greater than that of women’s(χ2=86.53, 44.77, 21.88, P<0.01). The differences of the proportion of schools with faucets available in toilets and within 5 meters around toilets, with sinks in or around the toilets, with sinks equipped with soap in or around the toilets were of statistical significance(χ2=90.02, 10.40, 41.96, P<0.01). Conclusion During 2016 to 2018, the environment sanitation of the three major rural primary and middle schools in Shaanxi Province needs to improve corresponding supporting facilities, and increase publicity to improve teachers and students’ awareness of health and safety.