The objective of this study is to investigate the effect of chemokine CXCR4 on the apoptosis of gastric cancer cells through IL-6/STAT3 signaling pathway and to explore the related mechanisms.Fluorescence quantitative PCR and Western blot were performed to detect the mRNA and protein expression levels of the chemokine CXCR4 in human gastric cancer tissues and adjacent non-cancerous tissues(PCT).Next,CXCR4 knockdown and overexpression were achieved by transfecting SGC7901 gastric cancer cell line with lentiviral vectors.TUNEL staining was used to evaluate the apoptosis of SGC7901 cells,while MTT assay was employed to measure cell proliferation.Western blot was conducted to determine the expression of apoptosis-related proteins Bax and Bcl2.Further,enzyme-linked immunosorbent assay(ELISA)was employed to measure the secretion levels of inflammatory cytokines.Real-time fluorescent quantitative PCR(RT-PCR)was utilized to quantify the expression of IL-6 mRNA in the IL-6/STAT3 signaling pathway,and Western blot was performed to analyze the expression of STAT3-Ser727 protein.In addition,after knocking down CXCR4 in SGC7901 cells,IL-6/STAT3 signaling pathway agonist lipopolysaccharide(LPS)was transfected,while in CXCR4-overexpressing SGC7901 cells,IL-6/STAT3 signaling pathway inhibitors angoline or bruceantinol were transfected.Then TUNEL staining was used to assess cell apoptosis,and Western blotting was performed to examine the expression levels of apoptosis-related proteins Bax and Bcl2 in these cells.Data showed that the expression of immune chemokine CXCR4 was increased in gastric cancer tissues,as compared with adjacent non-cancerous tissues.Single-cell gel electrophoresis analysis indicated that knockdown or overexpression of CXCR4 do not induce DNA damage in SGC7901 cells.TUNEL staining,MTT cell proliferation assay and Western blotting demonstrated that knockdown of CXCR4 in SGC7901 cells promoted the apoptosis in SGC7901 cells,while overexpression of CXCR4 inhibited the apoptosis.ELISA showed that knockdown of CXCR4 in SGC7901 cells promotes the expression of pro-inflammatory factors IL-1β and TNF-α,while inhibited the expression of anti-inflammatory factors IL-10 and TGF-β.Conversely,overexpression of CXCR4 demonstrated opposite effects.Finally,the activation of the IL-6/STAT3 signaling pathway significantly reduced the apoptosis induced by knocking down CXCR4 in iSGC7901 cells,whereas the inhibition of IL-6/STAT3 signaling pathway can significantly suppressed the induction of SGC7901 cells proliferation induced by CXCR4 overexpress.In conclusion,immunochemokine CXCR4 regulates gastric cancer cell apoptosis and inflammatory cytokines secretion through IL-6/STAT3 signaling pathway.

Objective To explore the path of personal traits, psychological capital and career among new nurses in ClassⅢ Grade A Chinese medical hospitals, so as to provide a reference for career planning management for new nurses. Methods In September 2016, we selected 170 new nurses at three ClassⅢGrade A Chinese medical hospitals in Zhejiang Province as subjects by convenience sampling. Career Condition Evaluation Scale, Psychological Capital Questionnaire(PCQ) and Eysenck Personality Questionnaire (EPQ) were used to investigate career, psychological capital and personal traits of new nurses. Pearson correlation was used to analyze the correlation among psychological capital, personal traits and career condition and to establish the path correlation model. Results A total of 170 questionnaires were sent out and 158 valid questionnaires were collected with 92.94% for the valid recovery rate. The total scores of personal traits, psychological capital and career were (39.59±12.89), (84.69±14.57) and (78.93±13.67) respectively. Psychological capital had a positive correlation with the career condition in new nurses (P＜0.05). In personal traits, psychoticism was correlated with the career identity and concealment was positively correlated with the willingness to remain (P＜0.05). Psychological capital had a positive prediction effect with the career of new nurses with 0.78 for the path coefficient; personal traits had positive effects on psychological capital with 0.17 for the path coefficient;personal traits had positive effects on career condition with 0.15 for the path coefficient. Psychological capital had a partial mediating role between psychological capital and career prompting personal traits had direct and indirect effects on the career condition. Conclusions Nursing managers should provide an education path of career planning for new nurses based on psychological capital intervention model to cultivate hope quality, optimism and anti-frustration ability of new nurses. Besides, nursing managers should assign jobs and collocate work team according to personal traits of new nurses to create harmonious organizational climate for staff and to promote career development of them.

Background Tin and its compounds can cause serious harm to human respiratory system and nervous system, but there is no corresponding national standard method for the determination of tin in PM_2.5. Objective To establish a method for the determination of tin and its compounds in PM_2.5 by atomic fluorescence spectrometry (AFS) after ultrasonic extraction with concentrated hydrochloric acid. Methods We extracted a fixed volume of air at a constant speed through a sampler with preset cutting characteristics to trap PM_2.5 in the ambient air on quartz filter membranes. By selecting extraction solvent, comparing extraction temperature and time, and adjusting the acidity of solution to be measured, the sample pretreatment process was optimized, and a method for the determination of tin and its compounds in PM_2.5 by AFS was proposed, and its performance indexes such as linearity, detection limit, and lower limit of quantification were obtained. The accuracy and precision of the method were evaluated by the standard addition recovery test with blank quartz filter membranes, and the interference test was carried out by adding standard urban particulate samples. The proposed method and the method recommended by the “Handbook on Monitoring and Protection of Air Pollution (Haze) Effects on Population Health (2020)” (the Handbook) were applied to actual samples, and the results were compared. Results This experiment used concentrated hydrochloric acid as the extraction solvent. The higher the reaction temperature and the longer the reaction time, the higher the recovery rate. Therefore, 70 ℃ water bath ultrasonic extraction for 3 h was selected. In terms of the proposed method, the linear range of detection was from 5.00 μg·L⁻¹ to 50.00 μg·L⁻¹, with a correlation coefficient ≥0.999 and a detection limit of 0.27 μg·L⁻¹. When the quantitative detection of the lower limit was 0.90 μg·L⁻¹，and the sampling volume was 144 m³, the limit of quantification was 1.25 ng·m⁻³. The recovery rate of standard addition of blank quartz filter membranes was 94.1%-97.5%, with a relative standard deviation ≤3.2%; the recovery rate of standard addition of standard urban particulate matter samples was 93.5%-103.0%, and the relative standard deviation was ≤2.1%, indicating that coexisting components in PM_2.5 samples would not affect the determination of tin. For the 10 quartz filter membrane samples of PM_2.5 monitoring, the results of tin by the established method (extraction with concentrated hydrochloric acid) were higher than those of the Handbook recommended method (extraction with nitric acid), and the difference is (3.61±0.54) ng·m⁻³(t=21.303, P<0.05). Conclusion The established method for the determination of tin and its compounds in PM_2.5 by AFS after ultrasonic extraction with concentrated hydrochloric acid is simple, accurate, and suitable for laboratory determination of tin and its compounds in large quantities of PM_2.5 samples.

Objective:To investigate the dose-response relationship between serum polycyclic aromatic hydrocarbon adducts and serum complement C3 and C4 levels among children from a city in East China.Methods:In September 2016, two boarding schools in the air pollution exposure area and the control area (beyond the upwind of 30 km in the air pollution exposure area) in a city in East China were selected as the research site, and the eligible school-age children were recruited as the research objects. A total of 273 children were included, including 163 in the exposure group and 110 in the control group. The annual air pollutant data (PM 2.5, PM 10 and NO 2) of the two regions during the study period were collected. The exposure level of tobacco was evaluated by cotinine in urine. The levels of serum complement C3 and C4 were determined by automatic biochemical analyzer. The serum anti-7, 8, -dihydrodiol-9, 10-epoxide benzo[a]pyrene (BPDE)-albumin adduct levels were detected by ELISA. Linear regression model was used to explore the dose-response relationship between BPDE-albumin adducts and serum complement C3 and C4. Results:The age of 273 subjects was (13.67±0.37) years old, including 165 boys (60.4%). The average annual exposure levels of PM 2.5, PM 10 and NO 2 and the level of serum BPDE-albumin adducts in the exposure group were higher than those in the control group ( P<0.05). The results of linear regression model analysis showed that after adjusting age, sex, BMI z-score and urinary cotinine level, when the serum BPDE-albumin adduct level increased by 10%, the serum complement C4 level decreased by 1.2% ( P=0.017). After adjusting age, BMI z-score and urinary cotinine level, for every 10% increase in serum BPDE-albumin adduct level in boys, the serum complement C4 level decreased by 1.68% ( P=0.024). After adjusting age, sex and BMI z-score, the levels of serum complement C3 and C4 decreased by 1.31% and 3.57% respectively for every 10% increase in serum BPDE-albumin adducts among children in the urinary cotinine detection group ( P<0.05). Conclusion:There is a significant dose-response relationship between serum BPDE-albumin adducts and the complement C4 among children.

Objective:To investigate the dose-response relationship between serum polycyclic aromatic hydrocarbon adducts and serum complement C3 and C4 levels among children from a city in East China.Methods:In September 2016, two boarding schools in the air pollution exposure area and the control area (beyond the upwind of 30 km in the air pollution exposure area) in a city in East China were selected as the research site, and the eligible school-age children were recruited as the research objects. A total of 273 children were included, including 163 in the exposure group and 110 in the control group. The annual air pollutant data (PM 2.5, PM 10 and NO 2) of the two regions during the study period were collected. The exposure level of tobacco was evaluated by cotinine in urine. The levels of serum complement C3 and C4 were determined by automatic biochemical analyzer. The serum anti-7, 8, -dihydrodiol-9, 10-epoxide benzo[a]pyrene (BPDE)-albumin adduct levels were detected by ELISA. Linear regression model was used to explore the dose-response relationship between BPDE-albumin adducts and serum complement C3 and C4. Results:The age of 273 subjects was (13.67±0.37) years old, including 165 boys (60.4%). The average annual exposure levels of PM 2.5, PM 10 and NO 2 and the level of serum BPDE-albumin adducts in the exposure group were higher than those in the control group ( P<0.05). The results of linear regression model analysis showed that after adjusting age, sex, BMI z-score and urinary cotinine level, when the serum BPDE-albumin adduct level increased by 10%, the serum complement C4 level decreased by 1.2% ( P=0.017). After adjusting age, BMI z-score and urinary cotinine level, for every 10% increase in serum BPDE-albumin adduct level in boys, the serum complement C4 level decreased by 1.68% ( P=0.024). After adjusting age, sex and BMI z-score, the levels of serum complement C3 and C4 decreased by 1.31% and 3.57% respectively for every 10% increase in serum BPDE-albumin adducts among children in the urinary cotinine detection group ( P<0.05). Conclusion:There is a significant dose-response relationship between serum BPDE-albumin adducts and the complement C4 among children.