Space radiation is the most important environmental harmful factor in long-term manned spaceflight and deep space exploration, and it may produce deterministic and stochastic effects on tissues and organs. In-depth research into the biological effects, mechanisms, and protective measures of space radiation is essential and serves as an important foundation for exploring radiation biology and promoting major manned space projects. Firstly, this review introduces the spatiotemporal distribution characteristics of space radiation during low-earth orbit flights, manned lunar landings, and deep space exploration missions, as well as the health risks and challenges it posed to astronauts. Then, it discusses medical requirements and exposure limits, risk assessment, and protection technologies included in the space radiation protection system established internationally and over 30 years of Chinese manned spaceflight departments. Finally, it outlines the subsequent work and prospects for further research.

Objective:To compare the pregnancy outcomes of surviving fetuses in monochorionic diam-niotic(MCDA)twin pregnancies after selective feticide or spontaneous single intrauterine fetal demise(sIUFD),and to explore the influencing factors of prognosis.Methods:A total of 219 cases of intra-uterine death of one fetus in MCDA twin pregnancies admitted to Peking University Third Hospital from September 2010 to August 2021 were collected.According to the mode of fetal death,they were divided into the spontaneous sIUFD group(120 cases)and the selective feticide group(99 cases).Data on the maternal conditions during pregnancy,the situation of the intrauterine-dead fetus,and pregnancy out-comes were collected for retrospective case-analysis.Results:The live-birth rates of surviving fetuses in the spontaneous sIUFD group and the selective feticide group were 85.0％and 81.8％respectively,and the total perinatal survival rates of surviving fetuses were 73.3％and 81.8％respectively,and there were no statistically significant differences.Compared with the spontaneous sIUFD group,the selective feticide group had a greater gestational week at delivery,and lower rate of preterm birth before 37 weeks,neonatal asphyxia,and early neonatal mortality.Using the gestational week at delivery as the outcome variable,Cox regression analysis showed that the mode of fetal death was not a risk factor affecting the gestational week at delivery of the surviving fetus,while gestational hypertension and the gestational week of fetal death were independent risk factors affecting the gestational week at delivery of the surviving fetus.Using preterm birth before 37 weeks,intrauterine death of the surviving fetus,and abnormal neonatal cranial ultrasound as outcome variables respectively,unconditional logistic regression analysis showed that the mode of fetal death,the gestational week of fetal death,the position of the dead fetus,and fetal complications were independent risk factors affecting the outcomes of the above-mentioned survi-ving fetuses.According to the results of the univariate analysis,the above risk factors were included in the multivariate regression analysis,and the results were the same as those of the univariate analysis.Conclusion:For MCDA twin pregnancy patients with severe twin-related complications,the prognosis of surviving fetuses after selective feticide is better.The proactive intrauterine intervention and treatment are of great significance for improving the prognosis of surviving fetuses.

Objective:To compare the pregnancy outcomes of surviving fetuses in monochorionic diam-niotic(MCDA)twin pregnancies after selective feticide or spontaneous single intrauterine fetal demise(sIUFD),and to explore the influencing factors of prognosis.Methods:A total of 219 cases of intra-uterine death of one fetus in MCDA twin pregnancies admitted to Peking University Third Hospital from September 2010 to August 2021 were collected.According to the mode of fetal death,they were divided into the spontaneous sIUFD group(120 cases)and the selective feticide group(99 cases).Data on the maternal conditions during pregnancy,the situation of the intrauterine-dead fetus,and pregnancy out-comes were collected for retrospective case-analysis.Results:The live-birth rates of surviving fetuses in the spontaneous sIUFD group and the selective feticide group were 85.0％and 81.8％respectively,and the total perinatal survival rates of surviving fetuses were 73.3％and 81.8％respectively,and there were no statistically significant differences.Compared with the spontaneous sIUFD group,the selective feticide group had a greater gestational week at delivery,and lower rate of preterm birth before 37 weeks,neonatal asphyxia,and early neonatal mortality.Using the gestational week at delivery as the outcome variable,Cox regression analysis showed that the mode of fetal death was not a risk factor affecting the gestational week at delivery of the surviving fetus,while gestational hypertension and the gestational week of fetal death were independent risk factors affecting the gestational week at delivery of the surviving fetus.Using preterm birth before 37 weeks,intrauterine death of the surviving fetus,and abnormal neonatal cranial ultrasound as outcome variables respectively,unconditional logistic regression analysis showed that the mode of fetal death,the gestational week of fetal death,the position of the dead fetus,and fetal complications were independent risk factors affecting the outcomes of the above-mentioned survi-ving fetuses.According to the results of the univariate analysis,the above risk factors were included in the multivariate regression analysis,and the results were the same as those of the univariate analysis.Conclusion:For MCDA twin pregnancy patients with severe twin-related complications,the prognosis of surviving fetuses after selective feticide is better.The proactive intrauterine intervention and treatment are of great significance for improving the prognosis of surviving fetuses.

Space radiation is the most important environmental harmful factor in long-term manned spaceflight and deep space exploration, and it may produce deterministic and stochastic effects on tissues and organs. In-depth research into the biological effects, mechanisms, and protective measures of space radiation is essential and serves as an important foundation for exploring radiation biology and promoting major manned space projects. Firstly, this review introduces the spatiotemporal distribution characteristics of space radiation during low-earth orbit flights, manned lunar landings, and deep space exploration missions, as well as the health risks and challenges it posed to astronauts. Then, it discusses medical requirements and exposure limits, risk assessment, and protection technologies included in the space radiation protection system established internationally and over 30 years of Chinese manned spaceflight departments. Finally, it outlines the subsequent work and prospects for further research.

Objective: To investigate the function and potential mechanism of hepatocellular carcinoma(HCC) cells-derived extracellular nicotinamide phosphoribosyl transferase(eNAMPT) in the angiogenesis of human umbilical vein endothelial cells(HUVEC). Methods: The eNAMPT secretion of HCC cells were stimulated by hypoxia treatment and investigated the angiogenesis of HUVEC was investigated by tube formation assays. Transcriptomic RNA sequencing(RNA-seq) analyses of HUVEC under eNAMPT treatment were used to explore the mechanism of the effect of eNAMPT-insulin receptor(INSR) axis on angiogenesis. Western blot was used to detect the effects of eNAMPT-INSR axis on protein expression of HUVEC cells. qRT-PCR was used to detect the influence of eNAMPT-INSR axis on the expression of HUVEC intracellular related target genes. Results: ELISA and Western blot results showed that the protein level of eNAMPT in the culture supernatant of HCC cells increased significantly after hypoxia stimulation.In vitroangiogenesis assay results showed that eNAMPT significantly increased the nodules number and total length of tubes in HUVEC. The transcriptome sequencing results of HUVEC showed that eNAMPT, as an insulin analogue, participated in the regulation of biological processes such as cell migration and angiogenesis in HUVEC, and might promote angiogenesis by activating insulin-like signaling pathways. Western blot results showed that the eNAMPT-INSR axis affected p-AKT and p-ERK1/2 protein levels in PI3K-AKT and MAPK-ERK1/2 signaling pathways in HUVEC. qRT-PCR results showed that the eNAMPT-INSR axis affected the expression of angiogenesis related target genes MMP2, MMP9 and VEGF in HUVEC. Conclusion eNAMPT secreted by HCC cells promotes angiogenesis by binding INSR to activate the PI3K-AKT and MAPK-ERK1/2 signaling pathways.

Grooming,as an evolutionarily conserved repetitive behavior,is common in various animals,including humans,and serves essential functions including,but not limited to,hygiene maintenance,thermoregulation,de-arousal,stress reduction,and social behaviors.In rodents,grooming involves a patterned and sequenced structure,known as the syntactic chain with four phases that comprise repeated stereotyped movements happening in a cephalocaudal progression style,beginning from the nose to the face,to the head,and finally ending with body licking.The context-dependent occurrence of grooming behavior indicates its adaptive significance.This review briefly summarizes the neural substrates responsible for rodent grooming behavior and explores its relevance in rodent models of neuropsychiatric disorders and neurodegenerative diseases with aberrant grooming phenotypes.We further emphasize the utility of rodent grooming as a reliable measure of repetitive behavior in neuropsychiatric models,holding promise for translational psychiatry.Herein,we mainly focus on rodent self-grooming.Allogrooming(grooming being applied on one animal by its conspecifics via licking or carefully nibbling)and heterogrooming(a form of grooming behavior directing towards another animal,which occurs in other contexts,such as maternal,sexual,aggressive,or social behaviors)are not covered due to space constraints.

Objective:To investigate the effect of prenatal dexamethasone on short-term outcomes and long-term neurological development in late preterm infants with twin pregnancy.Methods:A total of 315 pregnant women with twin pregnancy and their preterm infants who delivered in Peking University Third Hospital from January 2019 to December 2022 were retrospectively analyzed. The clinical data of pregnant women and preterm infants were collected. They were divided into non-medication group (93 pregnant women and 186 preterm infants), medication after 34 weeks group (123 pregnant women and 246 preterm infants), and medication before 34 weeks group (99 pregnant women and 198 preterm infants). Short-term outcomes of preterm infants were analyzed, including the incidence of neonatal respiratory distress syndrome (NRDS), wet lung, hypoglycemia, neonatal septicemia, intraventricular hemorrhage (IVH), bronchopulmonary dysplasia (BPD) and neonatal necrotizing enterocolitis (NEC). "Ages and Stages Questionnaire-Third Edition (ASQ-3) scale" was used to follow up the late neurological development of preterm infants at the corrected age of 6-54 months, and the level of neurological development was compared.Results:(1) General conditions: the gestational age at delivery in the non-medication group [36.1 weeks (35.6, 36.6 weeks)] was later than that in the medication after 34 weeks group [36.1 weeks (35.2, 36.4 weeks)] and medication before 34 weeks group [35.2 weeks (34.2, 36.2 weeks)] groups, and the differences were statistically significant (all P<0.05). After correcting for gestational age, there was no significant difference in birth weight among the three groups ( H=3.808, P=0.149). There were no significant differences in gender and the proportion of small for gestational age among the three groups (all P>0.05). (2) Short-term outcome: the incidence of wet lung was 7.0% (13/186), 11.0% (27/246) and 16.2% (32/198) in the non-medication group, medication after 34 weeks group and medication before 34 weeks group, respectively, and the difference was statistically significant ( P=0.018). There were no significant differences in the incidence rates of NRDS, hypoglycemia, sepsis, IVH, BPD, and NEC among the three groups (all P>0.05). Logistic regression analysis with gestational age and newborn birth weight as confounding factors showed that early gestational age ( OR=0.884, 95% CI: 0.837-0.933, P<0.001) and increased incidence of selective intrauterine growth restriction type I ( OR=2.967, 95% CI: 1.153-7.639, P=0.024) could both lead to an increased incidence of wet lung. (3) Long-term outcomes: a total of 109 pregnant women completed the follow-up, and 218 preterm infants with a corrected age of 6-54 months at the end of follow-up were enrolled, including 86 cases in the non-medication group, 66 cases in the medication after 34 weeks group, and 66 cases in the medication before 34 weeks group. There were no significant differences in the scores of communication, gross motor, fine motor, problem solving and personal-social among the three groups (all P>0.05). Conclusion:Prenatal administration of a single course of dexamethasone does not affect the neonatal birth weight and short-term outcomes of twin late preterm infants, and has no adverse effect on the neurological development of twin late preterm infants with a corrected age of 6-54 months.

Objective::To establish the Chinese population's amniotic fluid deepest vertical pocket (DVP) reference curves for dichorionic twin pregnancies and to investigate DVP links with adverse perinatal outcomes.Methods::This retrospective cohort study, conducted at Peking University Third Hospital from August 2011 to December 2020, used data from 375 women aged 20 to 45 years who had dichorionic twin pregnancies that were confirmed through first-trimester ultrasound. After exclusions, reference curves were developed using 318 women with 3,299 DVP scans, and the data analyzed included maternal demographics, pregnancy outcomes, ultrasound measurements, and neonatal information. DVPs were assessed via ultrasound at regular intervals and grouped by gestational age (GA) for analyses. Linear mixed models were used to create amniotic fluid reference curves. Associations between abnormalities and adverse perinatal outcomes were examined using Chi-squared or Fisher's exact tests. Logistic regression provided both crude and adjusted odds ratios, adjusting for pre-pregnancy weight, age, ethnicity, parity, and conception mode. Significance was set at P < 0.05 with 95% confidence intervals (CI), and the analyses were conducted using SPSS ver. 26.0 (IBM Corp., Armonk, NY) and SAS ver. 9.4 (SAS Institute Inc., Cary, NC, USA) software. Results::DVP increased from the first trimester to a maximum at 26 weeks (95% confidence interval ( CI), 2.7-8.3 cm for twin 1 and 2.8-7.9 cm for twin 2) and then decreased gradually toward term. Differences between twins 1 and 2 were significant after 26 weeks (95% CI for twin 1: 5.3, 5.5; 95% CI for twin 2: 4.4, 4.5; P < 0.010). Polyhydramnios of twin 1 increased the risk of large for GA. Oligohydramnios of twin 1 increased the risk of small for GA. Polyhydramnios of twin 2 increased the risk of small for GA, premature birth, and neonatal complications. Oligohydramnios of twin 2 increased the risk of preeclampsia, hypertensive disorder complicating pregnancy, and premature rupture of membranes. Conclusion::Reference curves for twin amniotic fluid volumes vary by GA and differ between twins, with potential implications for pregnancy outcomes.

Objective::To establish the Chinese population's amniotic fluid deepest vertical pocket (DVP) reference curves for dichorionic twin pregnancies and to investigate DVP links with adverse perinatal outcomes.Methods::This retrospective cohort study, conducted at Peking University Third Hospital from August 2011 to December 2020, used data from 375 women aged 20 to 45 years who had dichorionic twin pregnancies that were confirmed through first-trimester ultrasound. After exclusions, reference curves were developed using 318 women with 3,299 DVP scans, and the data analyzed included maternal demographics, pregnancy outcomes, ultrasound measurements, and neonatal information. DVPs were assessed via ultrasound at regular intervals and grouped by gestational age (GA) for analyses. Linear mixed models were used to create amniotic fluid reference curves. Associations between abnormalities and adverse perinatal outcomes were examined using Chi-squared or Fisher's exact tests. Logistic regression provided both crude and adjusted odds ratios, adjusting for pre-pregnancy weight, age, ethnicity, parity, and conception mode. Significance was set at P < 0.05 with 95% confidence intervals (CI), and the analyses were conducted using SPSS ver. 26.0 (IBM Corp., Armonk, NY) and SAS ver. 9.4 (SAS Institute Inc., Cary, NC, USA) software. Results::DVP increased from the first trimester to a maximum at 26 weeks (95% confidence interval ( CI), 2.7-8.3 cm for twin 1 and 2.8-7.9 cm for twin 2) and then decreased gradually toward term. Differences between twins 1 and 2 were significant after 26 weeks (95% CI for twin 1: 5.3, 5.5; 95% CI for twin 2: 4.4, 4.5; P < 0.010). Polyhydramnios of twin 1 increased the risk of large for GA. Oligohydramnios of twin 1 increased the risk of small for GA. Polyhydramnios of twin 2 increased the risk of small for GA, premature birth, and neonatal complications. Oligohydramnios of twin 2 increased the risk of preeclampsia, hypertensive disorder complicating pregnancy, and premature rupture of membranes. Conclusion::Reference curves for twin amniotic fluid volumes vary by GA and differ between twins, with potential implications for pregnancy outcomes.

Objective To explore the feasibility and safety of component separation technique (CST) in the laparoscopic treatment of gastric stromal tumor (GST) around the cardia.Methods Clinical data and follow-up results of 20 patients who underwent laparoscopic resection with CST in the treatment of GST around the cardia from January 2020 to June 2023 were retrospectively analyzed.Results All the 20 patients underwent surgery successfully without conversion to open surgery.The operative time was (90.5±18.9) min,the intraoperative blood loss was (22.0±14.7) ml,the postoperative ambulation time was (1.2±0.4) d,the first flatus time was (2.1±0.8) d,and the postoperative hospital stay was (5.7±1.2) d.Postoperative pathological results showed very low risk in 1 case,low risk in 14 cases,intermediate risk in 4 cases,and high risk in 1 case.The maximum tumor diameter was (3.6±0.9) cm.Postoperatively,1 patient experienced gastric emptying dysfunction and 1 had pleural effusion,both of whom were cured after active conservative treatment.There were no cardiac stenosis,gastric leakage,gastric bleeding,abdominal bleeding,incision infection,or other complications.All the patients were followed up for 6-36 months ( mean,15 months).They were able to eat normally,without choking,acid reflux,heartburn,or reflux symptoms.The CT scanning showed no tumor recurrence or metastasis.Conclusion Application of CST in the laparoscopic treatment of GST around the cardia is safe and feasible.