Objective To investigate the current status of nursing undergraduate students′ self-differentiation and career adaptability and analyze the correlation of the two, so as to provide a reference for nursing educators to offer employment guidance. Methods The Undergraduate Self-Differentiation Scale and The College Students′Career Adaptability Questionnaire were used to investigate 341 nursing undergraduates. Results The mean scores of the self-differentiation and the career adaptability were (3.70±0.60) points and (3.60±0.42) points, respectively. It showed that the total score of self-differentiation and its each dimension were positively correlated with career adaptability, the Pearson correlation coefficients were career adjustment 0.26, career interpersonal 0.38, career curiosity 0.32, career confidence 0.39, career concerns 0.27, career control 0.46, and the coefficients between two total scales were 0.46 (all P<0.05). Conclusions The self-differentiation level of nursing undergraduates could affect their career adaptation level, and clinical nursing educators can take corresponding measures to improve their career adaptability based on the characteristics of nursing students′self-differentiation.

Large population-based cohort studies conducted in the industrialized countries in different eras revealed that the use of antenatal corticosteroids for extremely preterm births (EPT, <28 gestational weeks) reached 60% or higher in the mid-1990s, accompanying by steadily declined perinatal mortality to 13%-22% in EPT with gestational age ≥25 weeks in developed countries. Notably, the survival rate of EPT with 23-24 weeks of gestation was over 50% in Sweden since 2005. There's a link between the increment of antenatal corticosteroids use and steady decline of mortality in EPT in the past three decades. High-quality evidence is needed to demonstrate the impact of antenatal corticosteroids on EPT perinatal outcomes under the current healthcare background in China. This review, focusing on the progression of antenatal corticosteroid treatment for EPT, may facilitate the quality improvement of maternal-fetal and infant healthcare in China.

The role and mechanism of vitamin D in fetal and neonatal lung development and chronic lung diseases development have raised attention in recent years. The placental transfer of vitamin D is the major source of vitamin D to the developing fetus. The lung, as a target organ for vitamin D, has its capacity for vitamin D metabolism and can form biologically active 1,25 dihydroxyvitamin D 3 in a paracrine manner to regulate lung development. Studies have shown that vitamin D is directly involved in the synthesis of lung surfactant proteins and phospholipids and promotes lung maturation such as lung epithelial-mesenchymal interactions and alveolar formation. Furthermore, it regulates immunity and improves placental function, which indirectly affects lung development. Vitamin D deficiency and vitamin D receptor polymorphisms have been found to be detrimental to the development of alveoli, and are associated with respiratory diseases such as neonatal respiratory distress syndrome and bronchopulmonary dysplasia (BPD). Experimental studies in animals have shown that antenatal vitamin D supplementation promotes lung maturation in preterm rats and postnatal vitamin D supplementation can alleviate the hyperoxia-induced inflammatory response in the lung and reduce BPD occurrence. Further high-quality research are needed to explore the dosing, timing, and impact factors of vitamin D for promoting fetal and neonatal lung maturation and clarify the mechanism of its prophylactic and therapeutic action.

Objective: To explore the combined effect of health literacy and nonsuicidal selfinjury on suiciderelated behaviors in junior middle school students, so as to provide reference for suicide prevention. Methods: During May to June 2023, a selffilling questionnaire survey was conducted among 7 367 junior middle school students selected by the methods of multistage stratified cluster sampling combined with conventient sampling in Chongqing. And a binary Logistic regression model was established to analyze the association of health literacy and NSSI with suiciderelated behaviors. Results: The detection rates of suicidal ideation, suicide planning, and suicide attempt among junior middle school students were 27.99%, 9.84%, and 4.64%, and the detection rate of NSSI was 38.03%, the rates of possessing total health literacy, functional health literacy, interactive health literacy, and critical health literacy were 62.68%, 66.51%, 54.24%, and 72.65%, respectively. Binary Logistic regression analyses showed that the absence of total health literacy and the three dimensions of health literacy and NSSI were positively correlated with suicidal ideation, suicide planning, and suicide attempt in junior middle school students (OR=1.42-10.30), and there were combined effects (OR=7.43-18.71) (P<0.05). Conclusions Lack of health literacy or the presence of NSSI and their coexistence increase the risk of suiciderelated behaviors, and health literacy level should be improved in junior middle school students to reduce NSSI and thereby prevent suiciderelated behaviors.

Objective: To explore the association between adverse childhood experiences (ACEs) and nonsuicidal selfinjury (NSSI) and suiciderelated behaviors among junior high school students, so as to provide a reference basis for the prevention of junior high school students suicide. Methods: From May to June 2023, a total of 7 392 junior high school students in three districts and counties of Chongqing were selected for self-administered questionnaire survey by stratified cluster sampling and convenience sampling methods. The questionnaire survey was conducted using the Chinese version of the Childhood Trauma Scale, Adolescent NSSI Assessment Questionnaire, and Suicide Related Behavior Questionnaire. Statistical analysis was performed by using χ 2 test, multifactorial Logistic regression model, and additional interaction analysis was used to calculate the estimated relative excess risk due to interaction (RERI), attributable proportion (AP), and synergy index (S), as well as 95% CI . Results: The detection rate of NSSI among junior high school students was 38.03%, the detection rate of ACEs was 41.76%, and the detection rates of suicidal ideation, suicide planning, and suicide attempt were 27.99%, 9.90%, and 4.75%, respectively. ACEs and its dimensions, and NSSI were the influencing factors for suiciderelated behaviors (OR=1.83-10.66, P<0.01). The result of the additive interaction showed that ACEs and NSSI, PN and NSSI, EA and NSSI, EN and NSSI all had additive interactions on suiciderelated behaviors (RERI=0.45-39.15, AP=0.10-1.09, S=1.02-3.92). And ACEs and its dimensions had additive interactions with NSSI on suiciderelated behaviors, for junior high school students with both ACEs and NSSI had 11.45, 20.38, and 28.76 times the risk of suicidal ideation, suicidal planning, and suicidal attempts as compared to junior high school students without ACEs and without NSSI (P<0.05). Conclusions ACEs and NSSI among junior high school students have an additive interaction effect on suicide related behaviors. ACEs and NSSI should be reduced to prevent suicidal behavior among middle school students.

Objective:To explore the effects of prenatal dexamethasone (DEX), postnatal pulmonary surfactant (PS) and respiratory support on the lung fluid clearance in premature rabbits at gestational age (GA) of 25-28 d (full term: 31 d) and their relationship with dynamic compliance of respiratory system (Cdyn), pulmonary morphology and other parameters.Methods:In our previous publications, premature rabbits were divided into four groups according to the intervention strategy: control group, PS-only group, DEX-only group and DEX+PS group in which data of several parameters including wet-to-dry lung weight ratio (W/D), Cdyn and volume density of alveoli (Vv) were retrieved and the lung tissue sections were scanned to recalculate the ratio of perivascular sheath to vascular sectional area (S/V) and lung injury scores-edema (LIS-E). W/D, LIS-E, S/V and Vv were adjusted for birth weight (BW) (divided by BW, represented as W/D/BW, LIS-E/BW, S/V/BW and Vv/BW) and mean Cdyn (Cdyn-m) was adopted. Based on the grouping of previous studies, the intervention groups in this study were divided as DEX group and non-DEX group, and PS group and non-PS group to analyze the influence of DEX and PS on the above parameters. Two independent samples t-test, one-way analysis of variance, LSD test, Kruskal-Wallis H test, Mann-Whitney U test and Pearson correlation analysis were used for statistical analysis. Results:A total of 196 newborn rabbits receiving mechanical ventilation after birth were included in this study. (1) Effects of DEX: compared with the non-DEX group, the DEX group showed increased W/D/BW (489±69 vs 421±113, t=－2.09), LIS-E/BW (188±57 vs 138±55, t=－2.61) and Vv/BW (20.1±4.9 vs 14.2±4.7, t=－3.60), but decreased S/V (0.33±0.23 vs 0.51±0.25, t=2.23) and S/V/W/D (0.05±0.03 vs 0.07±0.04, t=2.22) at 25 d of gestation; at 26 d of gestation, W/D/BW (472±76 vs 303±44, t=－8.75), LIS-E/BW (189±63 vs 106±36, t=－5.23), Cdyn-m [(0.16±0.07) vs (0.05±0.03) ml/(kg?cmH 2O), 1 cmH 2O=0.098 kPa; t=－7.29] and Vv/BW increased (22.4±5.0 vs 12.2±3.8, t=－7.46), while S/V (0.23±0.19 vs 0.62±0.38, t=4.10), S/V/BW (15.7±12.4 vs 25.7±17.3, t=2.20), S/V/W/D (0.03±0.03 vs 0.08±0.05, t=3.92) and propensity scores decreased [(12.5±1.2) vs (15.1±1.2) scores, t=7.00]; at 27 d of gestation, Cdyn-m increased [(0.23±0.12) vs (0.16±0.07) ml/(kg?cmH 2O), t=－2.43], but S/V (0.32±0.23 vs 0.57±0.39, t=2.57) and S/V/W/D decreased (0.05±0.04 vs 0.09±0.06, t=2.55); at 28 d of gestation, W/D/BW (270±64 vs 162±33, t=－8.09), LIS-E/BW (72±32 vs 35±20, t=－5.17), S/V (0.90±0.60 vs 0.59±0.48, t=－2.81), S/V/BW (34.0±23.6 vs 15.2±12.7, t=－3.77) and Vv/BW increased (16.9±4.3 vs 9.2±2.9, t=－8.04); the differences were all statistically significant (all P<0.05). (2) Effects of PS: compared with the non-PS group, the PS group had decreased LIS-E/BW at 25, 26 and 27 d of gestation, increased Cdyn-m and Vv/BW at 25 and 27 d of gestation and higher propensity scores at 25 d of gestation (all P<0.05). (3) The correlation between gestational age and each index: gestational age was positively correlated with S/V ( r=0.31, P<0.05), but negatively correlated with W/D/BW and LIS-E/BW ( r=－0.73 and－0.63, both P<0.05). Conclusions:The pharmacological action of prenatal DEX on lung fluid clearance is mainly confined to preterm rabbits at the GA of 28 d which is supported by mechanical ventilation. Prenatal treatment with DEX and/or postnatal PS can improve the early respiratory function in preterm rabbits between GA of 25-27 d, but had no substantial impact on lung fluid clearance. The GA-related lung maturation appears to play a crucial role, in comparison with medications, in lung fluid clearance.

Objective To analyze the epidemiological characteristics and risk factors of severe respiratory failure in elderly patients with chronic obstructive pulmonary disease (COPD). Methods A total of 288 COPD patients admitted to our hospital from January 2018 to December 2021 were selected. The patients were divided into control group (no severe respiratory failure) and observation group (severe respiratory failure) according to whether severe respiratory failure occurred during hospitalization. The FEV1 and FEV1/FVC values and clinical symptoms of the two groups were compared. Univariate analysis and logistic regression analysis were used to analyze the influencing factors of severe respiratory failure in COPD patients. Results Among of 288 COPD patients, 86 cases (29.86%) developed severe respiratory failure. The proportion of severe respiratory failure in male patients aged ≥70 years was significantly higher (P<0.05). The values of FEV1 and FEV1/FVC in the observation group were significantly lower than those in the control group (P<0.05). The proportion of dyspnea and nocturnal awakening in the observation group were significantly higher than those in the control group (P<0.05). Age ≥70 years old (OR=4.092), concurrent nosocomial infection (OR=4.756), concurrent hypoproteinemia (OR=3.826), and acute exacerbations >3 times per year (OR=4.573) were the risk factors for severe respiratory failure in elderly COPD patients (P<0.05). Conclusion The elderly COPD hospitalized patients have a higher risk of severe respiratory failure, and most of them are male patients over 70 years old. Especially for patients over 70 years old with hypoproteinemia, more than 3 acute exacerbations per year, and nosocomial infection, active intervention should be given to prevent the risk of severe respiratory failure.

BACKGROUND:Adjustable piezoelectric effect can promote tissue regeneration and repair.Piezoelectric materials are widely used in weight-bearing tissue engineering. OBJECTIVE:To prepare a piezoelectric film material that can promote bone regeneration,and to explore its structural characterization,electrical output performance,biocompatibility,and effect of electrical output on osteogenic differentiation of rabbit bone marrow mesenchymal stem cells. METHODS:Using poly-3-hydroxybutyrateco/4-hydroxybutyrate(P34HB)as raw material,barium calcium stannate titanate powder(Ba0.94Ca0.06Sn0.08Ti0.92O3,BCST)was added according to mass ratios of 0%,5%,10%,15%,and 20%.Dichloromethane was added to solve P34HB,and the thickness of 150-200 μm BCST/P34HB piezoelectric film was prepared by vacuum drying method.After polarization in the oil bath,the surface morphology,crystal phase composition,piezoelectric coefficient and open circuit voltage were tested.The effect of BCST/P34HB electrical output at 110 Hz and 0.25 N force on the proliferation and osteogenic differentiation of rabbit bone marrow mesenchymal stem cells was tested. RESULTS AND CONCLUSION:(1)Scanning electron microscopy,X-ray diffraction,water contact angle,piezoelectric coefficient and electrical output performance tests showed that when the mass ratio of BCST increased to 20%,the BCST/P34HB piezoelectric film had good piezoelectric properties(d33=5.9 pC/N)and electrical output performance(180 mV),which was closer to the suitable range of 500 mV for electrical stimulation.(2)Live and dead staining showed that on the first day of co-culture,15%group and 20%group showed less red fluorescence.On the 5th day of culture,the number of green fluorescence in each group was significantly higher than that on the first day,and the red fluorescence was not observed in the 10%,15%and 20%groups,and only a small amount of red fluorescence was observed in the 0%and 5%groups.(3)On the 1st,3rd and 5th days of co-culture with rabbit bone marrow mesenchymal stem cells,Almar blue staining exhibited that the number of cells in each group showed an increasing trend with the increase of time.On the 5th day of culture,the number of cells in the 20%group was significantly more than that in the 0%group(P<0.05).(4)On day 10 of osteogenic induction,alkaline phosphatase staining results showed that the positive rate of the 20%group was significantly higher than that of the 0%group(P=0.000 1).On day 21,alizarin red staining and quantitative analysis of calcium nodules showed a similar trend to alkaline phosphatase staining.Compared with the 0%group,the 15%group and 20%group showed significant differences(P<0.01,P<0.000 1).(5)The results showed that 20%BCST/P34HB films had good piezoelectric properties,electrical output properties,biocompatibility and the ability of promoting osteogenic differentiation of bone marrow mesenchymal stem cells.