Background Since the outbreak of the COVID-19 epidemic, staff of the centers for disease control and prevention (CDC) have been burdened with heavy epidemic prevention control, and excessive occupational stress can cause depression and other psychological problems. Objective To explore the status of occupational stress, resilience, and depression of CDC staff and potential relationships between them. Methods From December 2020 to April 2021, a survey was conducted at provincial and municipal levels, and the stratified cluster sampling method was used at county (district) level to select a total of 3514 samples. Their occupational stress, resilience, and depression status were evaluated using the Chinese Effort-Reward Imbalance Scale (ERI), the Chinese Connor-Davidson Resilience Scale (CD-RISC), and the Patient Health Questionnaire (PHQ-9). Independent sample t test, analysis of variance, χ² test, Pearson correlation analysis, and mediation test (structural equation model) were conducted. Results The positive rate of occupational stress was 34.29% in the CDC staff, the resilience score was 66.28±15.32, and the positive rate of depression was 48.58%. Significant differences were found in the positive rates of occupational stress among different groups of gender, age, education background, marital status, administrative duty, weekly exercise frequency, chronic disease prevalence, and participation in epidemic control (P<0.05); in the resilience scores among different groups of gender, age, administrative duty, weekly exercise frequency, chronic disease prevalence, and participation in epidemic control (P<0.05); in the positive rates of depression among different groups of gender, age, educational background, personal monthly income, weekly exercise frequency, chronic disease prevalence, and participation in epidemic control (P<0.05). Occupational stress was negatively correlated with resilience (r=−0.165, P<0.01). Resilience was negatively correlated with depression (r=−0.383, P<0.01). Occupational stress was positively correlated with depression (r=0.343, P<0.01). The structural equation embracing a partial mediating effect of resilience on the relationship occupational stress and depression was established, and the partial mediating effect was 0.039, accounting for 10.46% of the total effect. Conclusion High positive rates of occupational stress, reduced resilience, and depression are shown among CDC staff in the context of the COVID-19 epidemic, and resilience partially mediates the effect of occupational stress on depression. The study findings suggest that improving resilience may reduce occupational stress and depression in CDC staff.

Objective: To explore the age related increases and characteristics of static stance balance and control strategies of 3-6 years old preschool children,and to provide a reference for the research of children s physique and the practice of physical education. Methods: Using a 2×2×3 (proprioceptive×visual×age) three factor experimental design, standing balance was tested among 105 preschool children aged 3-6 years who were subjected to static for 15 s under four standing postures from January to March 2018. Quantitatively examine the static stance balance ability based on changes in the center of pressure (COP), and quantitatively examine the posture control strategy based on COP frequency domain analysis and nonlinear analysis. Results: Among children aged 3-, 4- and 5-6 years old under the condition of open eyes / hard ground AP_ MV and ML_ MV were 18.05, 16.00, 13.40; 13.55, 11.03, 10.12 mm/s respectively; Under the condition of closed eyes/hard ground, children in three age groupsAP_ MV and ML_ MV were 21.01, 19.60, 15.10; 12.20, 10.20, 10.00 mm/s respectively among three age groups of children. The results showed that the sloshing amplitude and average sloshing velocity decrease significantly with age( P <0.01). Under the conditions of open/hard ground and closed/hard ground, the high frequency band in the left-right direction and the low frequency band in the anterior posterior direction increased significantly with age ( P <0.01). Under the condition of open eyes/hard ground, three age groups of AP_ MF and AP_ HF among three age groups of children were 29.00, 28.61, 27.20； 7.45, 7.44 6.01, respectively, indicating that the middle and high frequency bands ( P <0.01) in the anterior posterior direction decreased significantly with age. ML_FD of children aged 3-, 4- and 5-6 years old under the condition of open eyes / hard ground and closed eyes / hard ground was 1.43, 1.44, 1.52; 1.49, 1.48, 1.56/mm, AP_ FD was 1.58, 1.56, 1.52; 1.56, 1.63, 1.61; AP_MSE was 6.81, 6.90, 5.61 ; 7.25 , 7.41,6.60，respectively. The results show that the fractal dimension in the left right direction increases significantly with age, while the fractal dimension and multi scale entropy in the front back direction decrease significantly( P <0.01). Conclusion The static stance balance ability of 3-6 years old preschool children shows non linear changes with age,the static posture balance ability of 5-6 years old preschool children is significantly better than that of 3-5 years old , and the balance control strategies of 5-6 years old preschool children is different from that of 3-5 years old.

Objective:To understand the characteristics and differences of diarrhea-related symptoms caused by different pathogens, and the clinical features of various pathogens causing diarrhea.Methods:Etiology surveillance program was conducted among 20 provinces of China from 2010 to 2016. The acute diarrhea outpatients were collected from clinics or hospitals. A questionnaire was used to survey demographics and clinical features. VFeces samples were taken for laboratory detection of 22 common diarrhea pathogens, to detect and analyze the clinical symptom pattern characteristics of the patient’s.Results:A total of 38 950 outpatients were enrolled from 20 provinces of China. The positive rates of Rotavirus and Norovirus were the highest among the five diarrhea-causing viruses (Rotavirus: 18.29%, Norovirus: 13.06%). In the isolation and culture of 17 diarrhea-causing bacterial, Escherichia coli showed the highest positive rates (6.25%). The clinical features of bacterial diarrhea and viral diarrhea were mainly reflected in the results of fecal traits and routine examination, but pathogenic Vibrio infection was similar to viral diarrhea. Conclusion:Infectious diarrhea presents different characteristics due to various symptoms which can provide a basis for clinical diagnosis.

Objective? To explore how to apply best practice guideline in teaching and the initial effects. Methods? After deeply investigating courses, this study selected best practice guideline by combining with existing problems in teaching. Combined with the first-level and second-level class, a careful design scheme was conducted by each course groups and multiple rounds of project argumentation. After determining the program and teaching resources, each guideline application course group began to fully implement according to their own program. Results? The best practice guidelines were successfully applied in 7 courses through various teaching forms including situation simulation, flipped classroom, case teaching as well as role playing which played an positive role in teaching content, teaching design and teaching evaluation. Conclusions? In the whole process of implementation, teachers and students feel that the application of best practice guideline in nursing teaching is helpful to expand the frontier content of teaching, establish the evidence-based concept of teachers and students and initially cultivate critical thinking. It also plays a positive role in arousing the enthusiasm of nursing students and the comprehensive application of the knowledge they have learned. It makes evaluation methods flexible and diversified and is also beneficial to the real and objective response to the learning effect of nursing students.

Objective: To evaluate the occupational health risk of decorative coating manufacturing enterprises and to explore the applicability of occupational hazard risk index model in the health risk assessment, so as to provide basis for the health management of enterprises. Methods: A decorative coating manufacturing enterprise in Hebei Province was chosen as research object, following the types of occupational hazards and contact patterns, the occupational hazard risk index model was used to evaluate occupational health risk factors of occupational hazards in the key positions of the decorative coating manufacturing enterprise, and measured with workplace test results and occupational health examination. Results: The positions of oily painters, water-borne painters, filling workers and packers who contacted noise were moderate harm. And positions of color workers who contacted chromic acid salts, oily painters who contacted butyl acetate were mild harm. Other positions were harmless. The abnormal rate of contacting noise in physical examination results was 6.25%, and the abnormality was not checked by other risk factors. Conclusion The occupational hazard risk index model can be used in the occupational health risk assessment of decorative coating manufacturing enterprises, and noise was the key harzard among occupational harzards in this enterprise.

BACKGROUND:Accumulative evidence supports that co-culture technology can be applied to construct the tissue-engineered cartilage with excellent biological characters. OBJECTIVE:To elaborate the co-culture concept and conclude and analyze seed cell sources, cel mixed ratio, spatial y-defined co-culture models and biomaterials in co-culture systems to conclude and analyze the biological characters of tissue-engineered cartilage, and to prospect progression of co-culture systems in cartilage tissue engineering. METHODS:The first author retrieved the databases of PubMed, Web of Science, and CNKI for relative papers published from January 1976 to May 2016 using the keywords ofco-culture, co-culture systems;articular cartilage, chondrocytes, mesenchymal stem cells;tissue engineering, articular cartilage tissue engineeringin English and Chinese, respectively. Finally 60 literatures were included in result analysis, including 1 Chinese and 59 English articles. RESULTS AND CONCLUSION:Co-culture technology emphasizes the role of microenvironment in terms of various physical, chemical and biological factors in the cell processing. In cartilage tissue engineering, co-culture systems contribute to maintain the viability and natural cell phenotype of chondrocytes and induce cartilage differentiation of mesenchymal stem cells. In addition, co-culture technology provides a novel way for cartilage tissue engineering to overcome the shortage of chondrocytes and repair injury to the cartilage-subchondral bone. However, the mechanisms of cell-cell interaction in co-culture systems still need to be explored in depth, so as to optimize the co-culturing conditions and construct perfect tissue-engineered cartilage.

BACKGROUND:Soft tissue engineering mainly includes seed cells,scaffolds,cytokines and bioreactors,among which,the scaffolds are the key link in the construction of tissue-engineered cartilage.OBJECTIVE:To prepare an articular cartilage extracellular matrix/human umbilical cord Wharton gel porous scaffold,and to evaluate its physicochemical properties and biocompatibility.METHODS:The articular cartilage extracellular matrix/human umbilical cord Wharton gel porous scaffold was prepared by freeze thawing drying method using porcine articular cartilage extracellular matrix and human umbilical cord Wharton glue as raw materials.The porosity,water absorption,tissue composition and longitudinal compressive elastic modulus of the scaffold were measured and histologically stained.Rabbit chondrocytes were co-cultured with the articular cartilage extracellular matrix/human umbilical cord Wharton gel porous scaffold for 7 days.Then,scanning electron microscopy,live-dead cell staining and hematoxylin-eosin staining were performed.In addition,rabbit chondrocytes were cultured in the extract of the articular cartilage extracellular matrix/human umbilical cord Wharton gel porous scaffold and cell culture medium for 6 days,respectively;and MTT assay was used to detect cell proliferation.RESULTS AND CONCLUSION:The articular cartilage extracellular matrix/human umbilical cord Wharton gel porous scaffolds had a cross-section of uniform porous network structure and a vertical cross-section of the vertical tubular structure,and the pore wall was densely covered with cartilage fibers.The composite porous scaffold was positive for hematoxylin-eosin staining,safranin O staining and toluidine blue staining,and contained collagen and glycosaminoglycan ingredients.The water absorption,porosity and longitudinal compressive elastic modulus of the scaffolds were (17.418 8±0.909 0)％,(81.495 1±6.621 0)％ and (2.833 3±0.456 4) kPa,respectively.After 7 days of co-culture,rabbit chondrocytes adhered to the scaffold and proliferated,and further grew into the pores of the scaffold.Moreover,the scaffold was non-toxic to the rabbit chondrocytes.To conclude,the physiochemical properties and biochemical components of articular cartilage extracellular matrix/human umbilical cord Wharton gel porous scaffolds are similar to those of natural cartilage,and the scaffold has good biocompatibility.

OBJECTIVE: To explore the relationship of exposure to occupational hazards,labor intensity,dietary factors and the metabolic syndrome( MS) in male rolling mill workers. METHODS: A total of 1 105 male workers in a rolling mill were studied as research objects by judgment sampling method. The basic information of the subjects was collected by questionnaire survey and health examination. The prevalence of MS was analyzed according to different individual characteristics of workers. Multi-factor logistic regression analysis was conducted for analysis of the affecting factors of MS.RESULTS: The prevalence of MS in the subjects was 32. 5%( 359/1 105). The prevalence of MS in workers exposed to occupational hazards was higher than that in the control group( 33. 5% vs 20. 2%,P < 0. 05). The prevalence of MS increased with age( P < 0. 05),and decreased with the increase of labor intensity and family per capita monthly income( P < 0. 05). The prevalence of MS in smokers was higher than that in non-smokers( P < 0. 017),and the prevalence of MS in workers with animal dietary was higher than those with balanced dietary and with traditional dietary( P < 0. 017).The multivariate logistic regression analysis showed that after the adjustment of confounding factors such as age,seniority,family per capita monthly income,smoking and drinking,MS risk in a single factor of carbon monoxide exposure group,high temperature combined with carbon monoxide exposure group and high temperature combined with noise exposure group were higher than that of the control group without exposure to occupational hazards respectively( P < 0. 05),and the ratio of the 95% confidence interval were 2. 246( 1. 097-4. 597),2. 581( 1. 308-5. 094) and 2. 435( 1. 281-4. 627). The risk of MS in workers with animal dietary was higher than that with traditional dietary( P < 0. 01),the odds ratio and 95%confidence interval was 1. 497( 1. 106-2. 025). The grade of MS was 24. 6% lower than the original labor intensity with each increasing grade of risk( P < 0. 05). CONCLUSION: The animal dietary,increased labor intensity,exposure to carbon monoxide,high temperature combined with carbon monoxide and high temperature combined with noise can all increase the risk of MS.

Objective: To investigate the value of means of surfaces with nonhomogeneity (MSN) in esti-mating the incidence of pneumoconiosis. Methods: Based on the principal component analysis, all counties (districts) of Hebei Province, China, were divided into three categories according to the degree of pneumoconiosis hazards and the MSN model was used to estimate the incidence rate of pneumoconiosis and the number of pneu-moconiosis cases using the data of the incidence of pneumoconiosis in 2010. Results: With reference to the appli-cation requirements of the MSN model, results of the principal component analysis, and expert experience, the 172 counties (districts) in Hebei Province were divided into three categories with mild, moderate, and severe pneumoconiosis hazards. There were 74, 61, and 49 counties in the above categories, respectively, and 12, 12, and 25 counties were selected from them, respectively. The estimated number of pneumoconiosis cases in Hebei Province was 2105, and the incidence rate was 261.5 per hundred thousand, with a standard error of esti-mation of 389.9 per hundred thousand. Conclusion The MSN model provides a new thought and method for es-timating the number of pneumoconiosis cases.