Psychometric validation of Social Network Sites Use Motivation (SNSUM) Scale among Chinese adolescents and undergraduates.

Research into the motivations for using social network sites has greatly increased in recent years. However, few studies have examined the psychometric validation of scales measuring these motivations. This research revised the Social Network Sites Use Motivations (SNSUM) Scale for application in a Chinese context. A total of 931 Chinese adolescents and undergraduates, aged 16-23 years, completed the adapted SNSUM scale and assessments of life satisfaction. Item analysis indicated all items in the SNSUM scale were retained for exploratory factor analysis (EFA). EFA results revealed a five-factor solution, explaining 75.37 % of the total variance, with factor loadings exceeding 0.40. This factor structure aligns with theoretical expectations and previous studies. Confirmatory factor analysis (χ2 = 415.633; df = 92, CFI = 0.934, TLI = 0.914, RMSEA = 0.080) and measurement invariance indicate robust construct validity of the scale across diverse gender and age cohorts. It also showed high internal consistency (Cronbach's α = 0.950) and excellent test-retest reliability (intraclass correlation coefficient = 0.952). Notably, SNSUM demonstrated a significant positive correlation with life satisfaction (r = 0.531). The findings confirm that the scale has robust psychometric properties among Chinese adolescents and undergraduates, suggesting its applicability within the context of Chinese culture.

The cavitation characteristics of aerospace high-speed centrifugal pumps with different tip clearance.

This study investigates the Tip Clearance Cavitation (TCC) characteristics of three different Tip Clearances (TC) (0.4, 0.6, 0.8) and five inlet negative pressure conditions Pj = (- 20-60)kPa to improve the reliability of the aerospace high-speed centrifugal pump during in-orbit operation, based on the premise of good agreement between the TC 0.6 test curve and the simulation performance curve. Under negative pressure and high-speed conditions, the variation gradient of cavitation characteristics with various inlet negative pressures is non-linear and has a sudden change, but the trend becomes stable after the inlet negative pressure drops to a certain stage. The tip clearance cavitation characteristics vary from the blade surface cavitation characteristics due to the difference in forces on both sides. This study is a proper starting point for the design of aerospace power pumps.

Interaction effect of polycyclic aromatic hydrocarbon metabolites and cadmium on semen quality in nonsmokers.

Both cadmium (Cd) and polycyclic aromatic hydrocarbons (PAHs) are known reproductive toxicants, but their co-exposure and interaction effect on semen quality particularly in nonsmokers remain unknown. We included 333 nonsmoking men and analyzed their urine and semen samples for heavy metals and PAH metabolites. Restricted cubic spline models were used to explore the dose-response relationship between each OH-PAHs, Cd, and semen quality parameters; the generalized linear model was performed to examine the interaction of each urinary OH-PAH metabolite and Cd concentration on semen quality. Also, stratified analysis was applied to further illustrate the independent effect of PAHs on semen quality parameters in low and high concentration Cd subgroups. The dose-response and interaction effect of PAHs and Cd on male semen quality was observed. Stratified analysis in the high concentration Cd subgroup showed a negative association of 1-OHPyr concentration with semen motility. Our findings indicate that Cd not only modifies the association between PAHs and semen quality but can also exacerbate the toxic effect of pyrene on semen quality parameters. However, further studies with larger samples are needed to confirm the findings.

Correlation between urinary chromium level and semen quality in men attending an andrology laboratory.

Chromium is an essential element that is required for the normal physiology but can be toxic to humans above a certain level. In spite of growing interest in research on chromium exposure to human health consensus about its effect on human, semen quality has not been achieved. The aim of the present study is to evaluate the impact of chromium exposure on semen parameters. A total of 760 males attending andrology laboratory of Tongji Hospital, Wuhan, for routine semen analysis were enrolled and requested to provide semen and urine samples. The urine level of chromium was evaluated using inductively coupled plasma mass spectrometry (ICP-MS), and computer-assisted semen analysis (CASA) was applied to examine semen parameters. Associations between semen parameters and urinary chromium were analyzed by means of multivariate linear regression analysis. Multivariate analysis showed a negative association between the urinary concentrations of chromium and progressive motility (ß = - 0.014, p = 0.040) and total motility (ß = - 1.077, p = 0.048), while other semen parameters did not show any statistically significant changes. Urinary chromium could influence semen quality parameters and impair male fecundity.