Objective:To discuss the promotive effect of nerve growth factor(NGF),which is highly expressed in the adipose-derived stem cell(ADSC)-induced Schwann-like cells(SCLCs),on the growth of dorsal root ganglion(DRG)cell processes in the rats,and to clarify its mechanism.Methods:The ADSCs were extracted from the epididymal adipose tissue of the SD rats,and their multidirectional differentiation potential was identified through osteogenic,adipogenic,and chondrogenic induction.The ADSCs were induced to differentiate into the SCLCs,and the expression levels of glial fibrillary acidic protein(GFAP)and S100 calcium-binding protein β(S100β)protein in the ADSCs and SCLCs were detected by immunofluorescence staining and Western blotting methods.The DRG cells were isolated and cultured,and immunofluorescence staining was used to detect the βⅢ-tubulin expression in the DRG cells for identification.The SCLCs were co-cultured with the DRG cells(co-culture group),the single-culture DRG cells were regared as DRG group and toluidine blue staining was used to observe and measure the length of DRG cell processes under the optical microscope in co-culture group and DRG group.Small interfering RNA(siRNA)transfection was used to knock down NGF,and plasmid transfection was used to over-express NGF.Real-time fluorescence quantitative PCR(RT-qPCR)method was used to detect the NGF mRNA expression levels in the cells in various groups;enzyme-linked immunosorbent assay(ELISA)method was used to detect the NGF protein levels in the cell supernatants.The transfected SCLCs were co-cultured with DRG cells and divided into control group,siNC/vector group,NGF knockdown group(si-NGF group),and NGF over-expression group(oe-NGF group).The lengths of DRG cell processes in various groups were observed.Results:The primary ADSCs adhered within 24 h after seeding,with a small number of lipid droplets remaining.After 3 d of culture,the cells were mostly short spindle-shaped,fusiform,or polygonal,growing rapidly in a vortex pattern.After passaging,the cells exhibited a uniform morphology,appearing as long spindles arranged in a fish-school pattern.After 14 d of adipogenic induction,the cell morphology changed from spindle-shaped to flat-round,with translucent lipid droplets forming in the cytoplasm,which were stained red by Oil Red O.After 28 d of osteogenic induction,the cells appeared sand-like with blurred morphology,and calcified nodules were observed,which were stained red by Alizarin Red and deposited in the extracellular matrix.After 28 d of chondrogenic induction in a 3D culture system,millet-sized chondrogenic spheres formed.Frozen sections of the spheres were stained with Alcian Blue,and acidic mucopolysaccharides in the cartilage tissue were stained blue under the microscope.Under the fluorescence microscope,the third-passage purified ADSCs showed positive expression of CD29[fluorescein isothiocy anate(FITC)-labeled green fluorescence]and CD44(Cy3-labeled red fluorescence).The immunofluorescence staining results showed that GFAP was labeled with FITC(green fluorescence),and S100β was labeled with Cy3(red fluorescence).The Western blotting results showed that compared with ADSCs,the expression levels of S100β and GFAP proteins in the SCLCs were increased(P<0.05).The primary DRG cells began to adhere 6 h after conventional culture,and after 3 d,the cell bodies appeared round and bright,with two linear processes extending from them.Under fluorescence microscope,the cells positively expressed the neuron-specific marker βⅢ-tubulin,confirming that the isolated cells were DRG cells.Compared with the ADSCs,the NGF protein expression level in the SCLCs was increased(P<0.05).Compared with DRG group,the length of DRG cell processes in co-culture group was the highest when DRG cells and SCLCs were co-cultured at a 1∶2 ratio(P<0.05).The RT-qPCR results showed that compared with si-NC group,the expression levels of NGF mRNA in the cell supernatant in si-NGF-1,si-NGF-2,and si-NGF-3 groups were significantly decreased(P<0.05),with si-NGF-1 showing the highest knockdown efficiency,which was selected for subsequent experiments.The ELISA results showed that compared with si-NC group,the NGF levels in the cell supernatant of si-NGF-1,si-NGF-2,and si-NGF-3 groups were decreased(P<0.05).Compared with Vector group,the expression level of NGF mRNA and NGF protein level in the supernatant in oe-NGF group were increased(P<0.05).Compared with control group and siNC/vector group,the length of DRG cell processes in si-NGF group was decreased(P<0.05),while the length of DRG cell processes in oe-NGF group was increased(P<0.05).Conclusion:ADSCs can be directionally differentiated into SCLCs,and the differentiated cells highly express NGF.Knockdown or overexpression of NGF can affect the growth of DRG cell processes.

Using high-energy proton to image the region of interest can directly obtain the accurate estimation of the proton stopping power of the lesions,which is of great significance to reduce the range uncertainty in proton therapy.As a fundamental function of proton computed tomography(CT),radiographic imaging plays a crucial role in assisting clinical positioning.The study develops a compact proton CT detector based on an active array pixel CMOS chip in Monte-Carlo simulation toolkit Geant4,and evaluates the radiographic imaging capability of the system using 180 MeV protons.The angles of tracks are successfully reconstructed.CTP404,CTP528,and the CTP515 of specific materials are used for simulation,obtaining the spatial and density resolutions,and measuring the proton relative stopping power(RSP).The image signal-to-noise ratio is improved when using 2° proton scattering angle cut-off value.The spatial resolution is 3-4 lp/cm measured using CTP528 module.The density resolution is better than 0.05 g/cm3,and the RSP resolution is within 5%when CTP404 module is used.Through the imaging of CTP515 phantom of specific material,it is demonstrated that the system has potential for imaging common human tissues.

{L-End}Objective To analyze the correlation between occupational burnout and sleep quality among steelworkers. {L-End}Methods A total of 11 491 steelworkers from a large steel enterprise in Gansu Province were selected as the research subjects using convenient sampling method. The Burnout Questionnaire and the Pittsburgh Sleep Quality Index Scale were used to investigate their occupational burnout and sleep quality. Hierarchical regression analysis was used to analyze the effects of occupational burnout on the sleep quality. {L-End}Results The detection rate of occupational burnout and sleep disorder were 50.4% and 39.0%, respectively. There was a positive correlation between the level of occupational burnout and the total score of sleep quality (Spearman correlation coefficient=0.454, P<0.05). The results of hierarchical regression analysis, adjusting for confounding factors such as gender, age, marital status, education level, alcohol consumption, exercise, weekly working hours, seniority, work shift, noise exposure, dust exposure, and high-temperature work, showed that the score of occupational burnout was positively related to the score of sleep quality(P<0.01), explaining 16.0% of the variance in the score of sleep quality among these steelworkers. {L-End}Conclusion The detection rate of occupational burnout and sleep disorders are relatively high among the steelworkers in this enterprise. Higher levels of occupational burnout are associated with poorer sleep quality. Alleviating occupational burnout among steelworkers may contribute to improving their sleep quality.

Background Steel workers are exposed to occupational hazardous factors such as dust, noise, and heat, and often work in shifts, making them prone to sleep disorders. Objective To explore potential influencing factors of sleep disorders among workers in a steel enterprise in Gansu Province, and provide a basis for reducing the risk of sleep disorders among them. Methods From January to March 2022, a self-made questionnaire combined with the Pittsburgh Sleep Quality Index (PSQI) were used to investigate the employees of a steel enterprise in Gansu Province. According to their PSQI scores, they were divided into a normal sleep group and a sleep disorder group. The general demographic variables of the two groups were balanced by 1∶1 propensity score matching (PSM). Multiple logistic regression was used to analyze the contributing factors of sleep disorders. Restricted cubic spline (RCS) model was used to analyze potential dose-response relationship between weekly working hours and sleep disorders. Results The prevalence of sleep disorders in the steel workers was 48.06% (6029/12544). After PSM, 5847 pairs were successfully matched, and the distributions of matched variables were well balanced between the two groups. The results of multiple logistic regression showed that hypertension (OR=1.39, 95%CI: 1.24, 1.56), diabetes mellitus (OR=1.34, 95%CI: 1.07, 1.66), three-shift system (OR=1.26, 95%CI: 1.12, 1.41), dust exposure (OR=1.14, 95%CI: 1.01, 1.29), noise exposure (OR=1.23, 95%CI: 1.09, 1.39), heat exposure (OR=1.16, 95%CI: 1.04, 1.29), and work injury (OR=1.22, 95%CI: 1.02, 1.46) increased the risk of sleep disorders. Compared with workers with < 10 years of service, those with 10-20 years (OR=1.31, 95%CI: 1.19, 1.44), 20-30 years (OR=1.34, 95%CI: 1.19, 1.52), and ≥30 years of service (OR=1.35, 95%CI: 1.19, 1.53) had a higher risk of sleep disorders. Compared with non-exercise workers, the risk of developing sleep disorders was lower in workers with occasional exercise (OR=0.61, 95%CI: 0.56, 0.66) and regular exercise (OR=0.55, 95%CI: 0.49, 0.62). The RCS model showed that the weekly working hours and sleep disorders in the steel workers showed a nonlinear dose-response relationship (P<0.05 for overall trend, P<0.05 for nonlinear test). The relationship between weekly working hours and sleep disorders showed a "U" shaped distribution, with a significant increase in the risk of sleep disorders when the weekly working hours exceeded 49 h. Conclusion The non-occupational influencing factors of sleep disorders of employees in the steel enterprise include hypertension, diabetes, physical exercise, and occupational influencing factors include length of service, weekly working hours, shifts, dust exposure, noise exposure, heat exposure, and work injuries. It is recommended to consider both occupational and non-occupational factors to formulate appropriate sleep disorder prevention and control measures for steel employees to reduce the risk of sleep disorders.

Objective:To analyze the phenotypic and genomic characteristics of Salmonella isolates recovered from meat products in Beijing wholesale markets. Methods:A total of 336 Salmonella strains from meat products collected from wholesale markets in Beijing were tested for antimicrobial resistance to 25 antimicrobial compounds by micro-broth dilution method; whole genome data were sequenced, followed by the serotype and ST type prediction by Seqsero2 and SISTR software, and the drug resistance genes and virulence factors were also predicted with CARD and VFDB databases of Abricate software; Salmonella serotyping assay kit and serum agglutination method were used for serotype confirmation of some isolates with different genome prediction results. Results:The resistance rates to Nalidixic acid and Ampicillin were 62.5% (210/336) and 55.1% (185/336), respectively, and all isolates were susceptible to Tigecyclin, Cefoxitin and Carbapenem antimicrobial compounds; 207 isolates (61.6%, 207/336) were multi-drug resistant, some could even be resistant to ten categories of drugs at the same time, and the most common antimicrobial resistance spectrum was NAL-AMP-SAM. A total of 24 serotypes were detected with predominant serotypes of Enteritidis (34.5%, 116/336), Derby (17.3%, 58/336) and Indiana (10.4%, 35/336). A total of 27 ST types were detected, the dominant type was ST11; ST types were in good consistency with serotypes; The detection rates of resistant genes referred to aminoglycosides, fluoroquinolones, β-lactams, sulfonamides and tetracyclines are more than 48%, and the first two reached 100%. The prediction of drug resistance genes was consistent with the results of antimicrobial resistance phenotype. A total of 122 virulence genes were predicted, 74 of which existing among all isolates.Conclusion:Salmonella in meat from the wholesale markets of Beijing has a high proportion of multiple drug resistance, a complex drug resistance spectrum, a variety of serotypes and ST types, and a high carrying rate of drug resistance gene and virulence gene; drug resistance phenotype and genotype are relatively consistent.

Objective:To analyze the phenotypic and genomic characteristics of Salmonella isolates recovered from meat products in Beijing wholesale markets. Methods:A total of 336 Salmonella strains from meat products collected from wholesale markets in Beijing were tested for antimicrobial resistance to 25 antimicrobial compounds by micro-broth dilution method; whole genome data were sequenced, followed by the serotype and ST type prediction by Seqsero2 and SISTR software, and the drug resistance genes and virulence factors were also predicted with CARD and VFDB databases of Abricate software; Salmonella serotyping assay kit and serum agglutination method were used for serotype confirmation of some isolates with different genome prediction results. Results:The resistance rates to Nalidixic acid and Ampicillin were 62.5% (210/336) and 55.1% (185/336), respectively, and all isolates were susceptible to Tigecyclin, Cefoxitin and Carbapenem antimicrobial compounds; 207 isolates (61.6%, 207/336) were multi-drug resistant, some could even be resistant to ten categories of drugs at the same time, and the most common antimicrobial resistance spectrum was NAL-AMP-SAM. A total of 24 serotypes were detected with predominant serotypes of Enteritidis (34.5%, 116/336), Derby (17.3%, 58/336) and Indiana (10.4%, 35/336). A total of 27 ST types were detected, the dominant type was ST11; ST types were in good consistency with serotypes; The detection rates of resistant genes referred to aminoglycosides, fluoroquinolones, β-lactams, sulfonamides and tetracyclines are more than 48%, and the first two reached 100%. The prediction of drug resistance genes was consistent with the results of antimicrobial resistance phenotype. A total of 122 virulence genes were predicted, 74 of which existing among all isolates.Conclusion:Salmonella in meat from the wholesale markets of Beijing has a high proportion of multiple drug resistance, a complex drug resistance spectrum, a variety of serotypes and ST types, and a high carrying rate of drug resistance gene and virulence gene; drug resistance phenotype and genotype are relatively consistent.

【Objective】 To analyze the influencing factors of blood re-donation among street voluntary blood donors in Nanjing, and to provide basis for increasing the proportion of blood donation/donors. 【Methods】 29 650 street voluntary blood donors in Nanjing from May 21, 2017 to May 21, 2018 in the information management system of Nanjing Red Cross Blood Center were taken as the sampling population, and 2 965 (10%) were randomly selected to ask whether they donated again and reasons by telephone calls. They were divided into re-donation group and lapsed group.The demographic variables and donation frequency of street blood donors in the two groups were analyzed and compared by Chi-square test, and multivariate logistic regression was used to analyze the influencing factors of re-donation of blood donors. 【Results】 The response rate of this survey was 63.37% (1 879/2 965), and the re-donation rate of street blood donors in Nanjing from May 2017 to May 2018 was 40.34% (758/1 879), which was lower than the re-donation rate of global blood donors as 50%. The primary motivation for street blood donors in Nanjing to donate blood again was "help others", accounted for 62.27% (472/758), and the primary deterrent to redonate blood again was "too busy to donate blood", accounted for 49.15% (551/1 121). 【Conclusion】 There is a certain gap between the rate of blood re-donation in Nanjing and worldwide, therefore, further incentive measures are needed and flexible recruitment and blood donation methods should be adopted to facilitate blood donation for donors.

【Objective】 To explore the promote and deter factors of blood donation among street blood donors in Nanjing, in order to improve the accuracy of street blood donors recruitment. 【Methods】 A questionnaire with high confidence was designed based on the theory of planned behavior(TPB). The multi-stage hierarchical sampling method was adopted according to the geographical location and economic development level of 11 districts(regions) in Nanjing, and the street blood donors were divided into three groups according to the history of blood donation: one donation(n=361), donation numbers ≥ 2(n=417)and non-donation (n=241). The blood donation behavior was investigated from four aspects as external promote factors (such as seeking a free blood examination, self-interest factors, etc.), internal promote factors(such as altruistic, self-interest factors, blood donation can help others, etc.), external deter factors (too busy to donate blood, opposition from my family, etc.) and internal deter actors ( worry about dizziness after blood donation, fear of needles, ect.). The database was established using Epidata software, and chi-square test was applied for statistical analysis between groups. 【Results】 The groups mainly affected by the promote factors (altruistic and self-interest factors) of Nanjing street population in blood donation were unmarried, 18~24 years old, childless, below bachelor degree, and have barely no income. The main groups less affected by the deter factors were students, male, unmarried, 18~24 years old, childless and have barely no income.Promote factors increases with the number of blood donations, while deter factors decreases with the number of blood donation. 【Conclusion】 TBP can better analyze and explain the promote and deter factors affecting blood donation behavior among street blood donors in Nanjing, which is helpful for blood stations to formulate targeted measures to improve the availability of street blood donors.

【Objective】 To investigate the feelings of blood donors during blood donation and its influencing factors, thus providing references for high quality blood donation service for blood banks. 【Methods】 A self-developed questionnaire concerning voluntary blood donation was randomly issued by the research group and recruited investigators among blood donors in 6 street blood donation sites of Nanjing Red Cross Blood Center at weekends during December 1~23, 2018. The basic information of blood donors, the difference of feelings during blood donation and the influencing factors were analyzed by descriptive analysis, chi-square test and binary Logistic regression analysis, respectively. 【Results】 A total of 405 questionnaires were issued, and all 405 copies were valid, with the response rate at 100% (405/405). Among the valid questionnaires, 46.67% (189/405) were first-time blood donors, 27.65% (112/405) had donated for 2~3 times, and 25.68% (104/405) donated more than 4 times. 53.59%(97/181), 23.7%(43/181) and 22.65%(41/181) of the above three groups of blood donors worried about the needles, and 55.48%(81/146), 22.60%(33/146) and 21.92%(32/146) worried about the blood outflow, 52.69% (88/167), 28.14% (47/167), and 19.16% (32/167 )worried about the pain during blood collection (P<0.05). The anxiety of unqualified blood test was similar to that of poor service (P>0.05). There were differences in blood donation experience among the three groups (P<0.05), and gender (P<0.05) was its influencing factor showed by binary Logistic regression analysis. 【Conclusion】 The majority of blood donors, who have donated at the street sites of Nanjing, are worried during blood donation collection. Therefore, the blood centers should provide high-quality services and humanized nursing interventions as well as strengthen the citizens′ awareness of blood donation.

Objective:To estimate the burden of hip fractures and related factors among the Chinese middle-aged and elderly population.Methods:Based on the data of China Health and Retirement Longitudinal Study (CHARLS) in 2015, the burden of hip fractures among Chinese middle-aged and elderly population was evaluated as the years lived with disability (YLD) rate. The relationship between gender, age (45-49, 50-59, 60-69 and ≥70 years old), educational level (no education, elementary school, junior high school, high school and above), region (urban, rural), gross domestic production (GDP) per capita (low, medium and high) and geographic area (northern, eastern, south-central, northwest and southwest regions) and the YLD rate of hip fractures were analyzed, respectively.Results:Excluding items with missing basic information and hip fracture data, a total of 17,830 subjects (8,405 males and 9,425 females) were included in the study with average age 61.6±9.8 years (range 45 to 105 years). The average age in male was 61.9±9.6 years, and that in female was 61.2±10.1 years. The prevalence of hip fractures was 2.3% (410/17,830). The total YLD rate was [694/100,000 (95% Uncertainty Interval ( UI): 462/100,000, 989/100,000)]. The YLD rates were similar between male [693/100,000 (95% UI: 461/100,000, 988/100,000)] and female [696/100,000 (95% UI: 463/100,000, 992/100,000)] subgroups. The YLD rate of hip fractures was increasing with age, which reached at maximum of 1,155/100,000 (95% UI: 769/100,000, 1,646/100,000) for participants aged 70 years or above. The rate was gradually decreased with the upgrade of the educational level. The participants with high school education and above reached the lowest of 434/100,000 (95% UI: 289/100,000, 619/100,000). In addition, the YLD rate of hip fractures in rural areas [721/100,000 (95% UI: 480/100,000, 1,027/100,000)] was higher than that in urban areas [650/100,000 (95% UI: 433/100,000, 926/100,000)]. The YLD rate in areas with higher GDP per capita [545/100,000 (95% UI: 363/100,000, 777/100,000)] was lower than that in areas with lower GDP per capita [761/100,000 (95% UI: 506/100,000, 1,084/100,000)]. Moreover, the participants living in the Northwest region were with the highest YLD rate of hip fractures [1,056/100,000 (95% UI: 703/100,000, 1,506/100,000)], followed by the Southwest region [887/100,000 (95% UI: 590/ 100,000, 1,264/100,000)] and the Northeast region [317/100,000 (95% UI: 211/100,000, 452/100,000)]. Conclusion:Hip fractures exerted heavy burdens on the Chinese middle-aged and elderly population. The YLD rate of hip fractures varied according to geographical regions, greater age, rural areas, low educational levels and low GDP per capita. These related factors could affect the disease burden of hip fractures in China.