Objective To investigate the longitudinal relationship between sleep duration(SD)and positive youth development(PYD)among primary and secondary school students in Chengdu city using a cross-lagged model,and to provide scientific evidence for enhancing sleep management practices for students.Methods A total of 4061 students of grades 3 through 9 from the Chengdu Child Positive Development Cohort were included in this three-wave longitudinal study.There was a one-year interval between one survey and the following round of survey,and the time points for the baseline,12-month follow-up,and 24-month follow-up surveys were designated T0,T1,and T2.The PYD of the participants was assessed using the Chinese version of the Positive Youth Development Scale.The demographic data and the average daily SD over the past month were collected.Spearman correlation analysis was performed to examine the associations between SD and PYD,and a cross-lagged model was used to investigate the longitudinal relationship between them.Results The average daily SD for the 3 rounds of surveys conducted at T0,T1,and T2 was 9.00(8.04,10.00)hours,10.44(9.67,11.11)hours,and 10.39(9.83,11.00)hours,respectively,while the PYD scores were 5.30(4.73,5.71),5.27(4.73,5.73),and 5.39(4.89,5.77),respectively.Statistical significance was found in the differences of SD and PYD scores across the 3 rounds(P＜0.05).Spearman correlation analysis revealed synchronous correlations between SD and PYD at all three time points(r=0.10 at T0,r=0.18 at T1,and r=0.21 at T2,P＜0.05)and significant lagged correlations(e.g.,r=0.10 for T1-PYD and T2-SD,and likewise,significant correlation was found for the 3 other cross-lagged paths).The cross-lagged model demonstrated that PYD at T0 and T1 positively predicted SD at T1 and T2,respectively(β0-1=0.116[95％CI,0.083-0.150],β1-2=0.097(95％CI,0.067-0.127),P＜0.05),and that SD at T0 and T1 also positively predicted PYD at T1 and T2(β0-1=0.028[95％CI,0-0.056],β1-2=0.042[95％CI,0.010-0.074],P＜0.05).According to these findings,a bidirectional predictive relationship between SD and PYD across different time points was observed in primary and secondary school students.Furthermore,PYD demonstrated better performance for predicting SD than SD did for PYD.Subgroup analysis by sex confirmed the robustness of the predictive power of PYD for SD.Conclusion This study reveals a positive bidirectional predictive relationship between SD and PYD among primary and secondary school students,suggesting that higher levels of PYD may contribute to adequate sleep.These findings provide critical scientific evidence for schools and families to strengthen sleep management and promote the holistic development and well-being of adolescents.

Objective:To investigate the efficacy of a domestically developed small esophageal cooling device in implementing targeted temperature management (TTM) after resuscitation and its impact on organ injury using a porcine model of cardiac arrest and resuscitation.Methods:Thirty healthy male domestic white pigs were randomly divided into four groups using a random number table: sham (S group, n=6), normothermia (NT group, n=8), surface cooling (SC group, n=8), and esophageal cooling (EC group, n=8). The S group underwent only surgical preparation, while the other groups were subjected to 12 minutes of ventricular fibrillation followed by 6 minutes of cardiopulmonary resuscitation to establish cardiac arrest. The S and NT groups maintained a core temperature of (37.5±0.5)°C using a surface blanket. In the SC and EC groups, therapeutic hypothermia was induced post-resuscitation via surface blanket or esophageal cooling catheter to achieve a target temperature of 34°C, maintained the target temperature (34±0.5)°C for 6 hours, followed by controlled rewarming at 0.5°C/h to 37°C. Core temperature was continuously monitored for 12 hours post-resuscitation. Hemodynamic parameters, including stroke volume (SV), global ejection fraction (GEF), extravascular lung water index (ELWI), and pulmonary vascular permeability index (PVPI), were assessed using pulse indicator continuous cardiac output (PiCCO) monitoring. Serum levels of cardiac troponin I (cTnI), neuron-specific enolase (NSE), creatinine (Cr), and intestinal fatty acid-binding protein (IFABP) were measured via ELISA at 2, 6, 12, and 24 hours post-resuscitation. Neurological outcomes were evaluated at 24 hours using the neurological deficit score (NDS) and cerebral performance category (CPC). Continuous variables were analyzed using one-way ANOVA. Results:During TTM, the EC group exhibited a faster cooling rate [(1.52±0.18)°C/h vs. (0.94±0.32)°C/h, P<0.05] and shorter time to target temperature [(2.32±0.43) h vs. (3.78±0.82) h, P<0.05] compared to the SC group, with comparable maintenance and rewarming ( P>0.05). Compared to the S group, the NT, SC, and EC groups demonstrated significant post-resuscitation multi-organ injury, characterized by reduced SV and GEF, elevated ELWI and PVPI, and increased serum cTnI, NSE, Cr, IFABP, NDS, and CPC scores (all P<0.05). Relative to the NT group, the SC and EC groups showed improved SV (at 1 h post-resuscitation), GEF (at 1, 2, 4, and 6 h), ELWI (at 12 h), and reduced cTnI and NSE (at 6 h), Cr and IFABP (at 2 h), and NDS and CPC (at 24 h) (all P<0.05). Compared to the SC group, the EC group exhibited lower PVPI (at 12 h), reduced cTnI, Cr, and IFABP (at 2 h), decreased NSE (at 2, 12, and 24 h), and improved NDS (at 24 h) (all P<0.05). Conclusions:In a porcine model of cardiac arrest and resuscitation, the domestic esophageal cooling device facilitated rapid induction, stable maintenance, and controlled rewarming during TTM, outperforming traditional surface cooling. This approach demonstrated superior organ protection, warranting further investigation.