Objective To establish a method for simultaneous determination of trace levels of microcystins,cylindrospermopsin,anatoxin,and nodularin in lake water based on liquid chromatography-tandem mass spectrometry(LC-MS/MS).Methods After being adjusted to alkaline conditions and mixed with six internal standards,the water samples were enriched using dual HLB and ENVI-Carb cartridges.The eluates were then evaporated under nitrogen,reconstituted,and subjected to instrumental analysis.Both water and acetonitrile containing 0.1%formic acid were used as mobile phases.An ACQUITY UPLC? BEH C18 column(150 mm×2.1 mm,1.7 μm)was selected to separate the target cyanotoxins.Multiple reaction monitoring was applied for data acquisition,and quantification was accomplished using internal standard methods.Results Within certain concentration ranges,all 14 cyanotoxins examined in the study showed good linearity,with all correlation coefficients greater than 0.998.When the water volume was 100 mL,the limits of detection and quantification for the 14 cyanotoxins were 0.1-0.9 ng/L and 0.3-2.9 ng/L,respectively,and spiked recoveries and relative standard deviations were 81.7%-132.9%and 1.2%-14.9%,respectively.In the 10 lake water samples analyzed,cylindrospermopsin,anatoxin-α,and multiple microcystins were detected.Conclusion The method developed in the study has high-throughput capacity,as well as high sensitivity,accuracy,and reliability.The method can be applied in the simultaneous detection of microcystins,cylindrospermopsin,anatoxin,and nodularin in lake water.

Objective:To explore the association between nighttime sleep duration and semen quality.Methods:By using a cross-sectional study, 3357 men were investigated by questionnaire for nighttime sleep duration, the time of falling asleep and falling asleep duration in the Reproductive Center of Shenzhen People's Hospital from August 2017 to August 2018. Semen quality parameters were obtained by computer-aided semen analysis system (CASA). Multiple linear regression was used to analyze the relationship between nighttime sleep duration and semen quality parameters. According to age and body mass index (BMI) stratification, the relationship between nighttime sleep duration and semen quality parameters was further discussed.Results:Compared with males with nighttime sleep duration between 6-8 h, the sperm progressive motility and total motility were 49.15% and 59.49%, respectively, which were significantly lower in the males with nighttime sleep duration≥8 h after adjusting for age, BMI, abstinence time, exercise, drinking and smoking, with regression coefficients, β=-3.16, 95% confidence interval ( CI)=-5.77--0.55 and β=-3.22, 95% CI=-5.93--0.51, respectively. Compared with the shortest duration of falling asleep group (<10 min), the increase of falling asleep duration was related to the decrease of sperm progressive motility ( P=0.045). The total sperm motility of falling asleep duration between 31-60 min group was also significantly lower than that of the shortest falling asleep duration group （ β=-3.80, 95% CI=-6.54--1.06, P=0.007）. Further stratification analysis showed that among the subjects aged 35 to 39 years, the sperm progressive motility of men with nighttime sleep duration less than 6 h was lower than that of 6-8 h group ( β=-4.01, 95% CI=-7.84-0.18, P=0.04). And among the subjects aged more than 40 years, the total sperm number of the men who slept ≥8 h at night was lower than that of the men with nighttime sleep duration between 6-8 h （percentage changes: -47.84%, 95% CI=-72.29%--2.19%, P=0.04）. The progressive and total sperm motility of men with BMI≥24 kg/m 2 and nighttime sleep duration ≥8 h were lower than those with BMI≥24 kg/m 2 in 6-8 h nighttime sleep duration group, and the corresponding regression coefficients were β=-5.75, 95% CI=-10.40--1.10, P=0.02 and β=-6.85, 95% CI=-11.69--2.00, P=0.01. Conclusion:In men ≥40 years old or BMI≥24 kg/m 2, the nighttime sleep duration ≥8 h were associated with the decreased sperm progressive motility and total motility.

Objective:To explore the association between nighttime sleep duration and semen quality.Methods:By using a cross-sectional study, 3357 men were investigated by questionnaire for nighttime sleep duration, the time of falling asleep and falling asleep duration in the Reproductive Center of Shenzhen People's Hospital from August 2017 to August 2018. Semen quality parameters were obtained by computer-aided semen analysis system (CASA). Multiple linear regression was used to analyze the relationship between nighttime sleep duration and semen quality parameters. According to age and body mass index (BMI) stratification, the relationship between nighttime sleep duration and semen quality parameters was further discussed.Results:Compared with males with nighttime sleep duration between 6-8 h, the sperm progressive motility and total motility were 49.15% and 59.49%, respectively, which were significantly lower in the males with nighttime sleep duration≥8 h after adjusting for age, BMI, abstinence time, exercise, drinking and smoking, with regression coefficients, β=-3.16, 95% confidence interval ( CI)=-5.77--0.55 and β=-3.22, 95% CI=-5.93--0.51, respectively. Compared with the shortest duration of falling asleep group (<10 min), the increase of falling asleep duration was related to the decrease of sperm progressive motility ( P=0.045). The total sperm motility of falling asleep duration between 31-60 min group was also significantly lower than that of the shortest falling asleep duration group （ β=-3.80, 95% CI=-6.54--1.06, P=0.007）. Further stratification analysis showed that among the subjects aged 35 to 39 years, the sperm progressive motility of men with nighttime sleep duration less than 6 h was lower than that of 6-8 h group ( β=-4.01, 95% CI=-7.84-0.18, P=0.04). And among the subjects aged more than 40 years, the total sperm number of the men who slept ≥8 h at night was lower than that of the men with nighttime sleep duration between 6-8 h （percentage changes: -47.84%, 95% CI=-72.29%--2.19%, P=0.04）. The progressive and total sperm motility of men with BMI≥24 kg/m 2 and nighttime sleep duration ≥8 h were lower than those with BMI≥24 kg/m 2 in 6-8 h nighttime sleep duration group, and the corresponding regression coefficients were β=-5.75, 95% CI=-10.40--1.10, P=0.02 and β=-6.85, 95% CI=-11.69--2.00, P=0.01. Conclusion:In men ≥40 years old or BMI≥24 kg/m 2, the nighttime sleep duration ≥8 h were associated with the decreased sperm progressive motility and total motility.

Objective: To explore the correlation between blood pressure and urinary phthalandione, MMP, MEP, MnBP, MiBP, PAEs. Methods: Three schools were selected from Shenzhen, China for the present study. A total of 765 firstgrade students of Han ethnicity were recruited voluntarily from the selected schools during September 2016 to June 2017. They were divided into normal blood pressure (BP) group (lower than P90 group) and high BP group (BP≥P90). Linear and Logistic regression models were used to analyze the relationships between blood pressure and urine phthalate metabolite levels. Results: Urinary MMP and MnBP in students of high BP group were significantly higher than that of students in normal BP group(t=13.12, 3.97, P<0.05). Linear regression models showed that Z score increased when MMP and MnBP levels increased(P<0.05). Logistic regression model suggested that the risk of high BP increased with the increment of MMP level adjusting creatinine, sex, age and BMI(OR=1.47, P<0.05). There was no statistical significance in the differences after adjusting many factors including family income and education level of parents(P>0.05). Conclusion Urinary phthalate metabolite levels are positively associated with blood pressure in first-grade children.

Objective To explore the relationship between mathematical characteristics of cardiotocograph in electronic fetal monitoring (EFM) and umbilical blood acidosis,and help to evaluate the clinical significance of indeterminate EFM.Methods A total of 85 vaginal delivery cases (or transfer to caesarean section during labor) hospitalized in Peking University Third Hospital during February 4 to December 5,2011 was enrolled in this retrospective study.EFM monitored 0.5-1 hour before delivery was recorded and the mathematical characteristics as the baseline,deceleration area per unit time (cm2/min),deceleration duration ratio and some other variables of EFM were analyzed.All cases were divided into acidosis (n=12) and non-acidosis group (n=73) based on the umbilical blood gas results.Rank sum test or t-test were used to compare the difference on mathematical characteristics between these two groups.Results The deceleration duration ratio and deceleration area per unit time in acidosis group were 0.56±0.17 and 0.45 cm2/min (0.38-0.79 cm2/min),which were higher than those in non acidosis group [0.42±0.14 and 0.30 cm2/min (0.19-0.40 cm2/min)],the differences were statistically significant (t=2.889,Z=2.587,both P＜0.05).There were no statistically significant differences in the number of mild variable deceleration and severe deceleration per unit time between acidosis group and non acidosis group [(0.44± 0.14)/min vs (0.41±0.13)/min,t=1.318,P＞0.05; 0.033/min (0.016-0.062/min) vs 0.016/min (0.008-0.033/min),Z=-1.596,P＞0.05].Conclusions The deceleration duration ratio and deceleration area per unit time can be used to assist the interpretation of indeterminate EFM.