Objective: To understand the impact of childhood trauma on psychological distress among upper grade elemetary school students, and to explore the mediating role of leisure activities in the relationship, so as to provide a basis for developing mental health intervention strategies. Methods: From August to November 2024, a combination of convenience sampling and stratified cluster random sampling was employed to recruit 1 373 fourth to sixth grade students from four primary schools in Harbin. The Childhood Trauma Questionnaire(CTQ), a self designed leisure activity scale (including active and passive leisure activities), and the Kessler Psychological Distress Scale (K10) were used to assess childhood trauma experiences, leisure activities, and levels of psychological distress. Spearman correlation analysis and linear regression analysis were conducted to explore the relationships among childhood trauma, leisure types, leisure time, and psychological distress. Based on the mediation analysis framework proposed by Hayes (Model 4), the mediating role of leisure types in the relationship between childhood trauma and psychological distress was examined. Results: Totally 19.1% of the upper elemetary school students exhibited psychological distress, while 30.2% had experienced childhood trauma. During school days, 64.6% of the students were reported of having leisure time concentrated between 1 and 5 hours per day, whereas 67.4% reported leisure time exceeding 5 hours per day on weekends. After controlling for potential demographic confounders such as gender, grade, ethnicity, household registration, being an only child, parents educational level, co residence, and whether parents are first time married,linear regression analysis showed that childhood trauma experience had positive predictive effect on psychological distress in upper primary school students( β =0.20, P <0.01). Leisure time showed no statistically significant association with psychological distress, both on school days ( β =-0.58 to -0.56) and weekends ( β =0.26- 0.98 )(all P >0.05). Active leisure activities were negatively associated with psychological distress ( β =-0.20), while passive leisure activities were positively associated with psychological distress ( β =0.29)(both P <0.01). Leisure type partially mediated the relationship between childhood trauma and psychological distress, accounting for 11.7% of the indirect effect. Conclusion Childhood trauma experiences positively predict psychological distress in upper elementary school students, and affect psychological distress through active leisure and passive leisure.

Kui was first recorded in The Rites of Zhou and is the earliest domesticated wild vegetable in China. In the Qi Min Yao Shu, Kui was called “the master of all vegetables” and has a long history of application in China. As a medicine, Kuizi was first recorded in Shen Nong’s Herbal Classic, which has a history of more than 2 000 years of medicinal use and a long history of clinical application. By researching the ancient and modern herbal literature, the first herbs texts of Kui were examined, various recorded texts, confused products and the history of the original medicinal use were clarified. It was concluded that the ancient herbal texts recorded the base plant of Kui as Malva verticillata L. belonging to family Malvaceae, which provided scientific basis for the development and utilization of Kui.

Objective: To explore the impact of sleep quality, experience of childhood maltreatment, and their interaction on depressive symptoms among middle school students, so as to provide the reference for early intervention of depressive symptoms among middle school students. Methods: From September to December 2023, a questionnaire survey was conducted among 1 231 students from two secondary schools in Harbin, Heilongjiang Province by a convenient sampling method. The survey included general demographic information, Childhood Trauma Questionnaire Short Form, Pittsburgh Sleep Quality Index and Short Version of Center for Epidemiological Studies Depression Scale. The Chi square test was used to analyze the differences in depressive symptom, sleep quality and childhood maltreatment among students with different demographic characteristics. Correlation analysis was conducted using Logistic regression, and interaction analysis was performed by both additive and multiplicative interaction models. Results: The detection rate of depressive symptoms among middle school students was 22.7%, and the rate for high school students (35.2%) was significantly higher than that for middle school students (17.0%) ( χ 2=50.35, P <0.01). The detection rates of depressive symptoms among middle school students with a history of childhood maltreatment and poor sleep quality were 45.8% and 44.0%, respectively. Multivariate Logistic regression analysis showed that compared to students without a history of childhood maltreatment, students with a history of childhood maltreatment had a higher risk of depressive symptoms ( OR =4.49，95% CI =3.31~ 6.09 , P <0.01);students with poor sleep quality had a higher risk of depressive symptoms than students with good sleep quality ( OR = 5.99，95% CI =4.37~8.22, P <0.01).The interaction results showed that the presence of childhood maltreatment and poor sleep quality had an additive interaction on the occurrence of depression in middle school students. Compared with students without childhood maltreatment and having good sleep quality, students with childhood maltreatment and poor sleep quality had a 22.49 times higher risk of developing depression ( OR =22.49，95% CI =14.22~35.59, P <0.01). Conclusion Depressive symptoms among middle school students are associated with childhood maltreatment and poor sleep quality, and there is an additive interaction between childhood maltreatment and poor sleep quality on the impact of depressive symptoms.

Epidural spinal cord stimulation (eSCS) represents an emerging neuromodulation technology that ameliorates motor dysfunction in patients with spinal cord injury, Parkinson's disease, and stroke by activating sensory afferent fibers, enhancing spinal cord neural network integration, optimizing brain-spinal cord information transmission, and inducing neural plasticity. This article reviews the mechanism, electrode implantation, and stimulation parameter of eSCS, and application of eSCS in spinal cord injury, Parkinson's disease, and stroke, aiming to provide valuable insight for its clinical implementation.

BACKGROUND:Mammary stem cells are vital for the development and homeostasis of mammary gland tissue.The occurrence of breast cancer has a close relationship with the mammary stem cells.Recent studies have shown that Hopx,as an important transcriptional regulator of morphogenesis and cell differentiation,has been confirmed to be expressed in a variety of adult stem cells such as nerves,intestines,hair follicles and lungs.However,its role in mammary stem cells has not been reported so far.OBJECTIVE:To investigate whether Hopx expression marks mammary stem cells.METHODS:(1) Female Hopx-LacZ transgenic mice aged 8 weeks were selected to detect the background expression of Hopx in breast tissue by β-galactosidase staining.(2) Female wild-type mice at 4,6,and 8 weeks of age and 14.5 days of gestation were selected for whole-tissue magenta staining and K14 and K8 immunofluorescence staining,respectively.(3) Female Hopx-CreERT2;Rosa26LacZ transgenic mice aged 8 weeks and 17.5 days of gestation were selected and stained with breast β-galactosidase.(4) The 4-week-old female Hopx-CreERT2;Rosa26LacZ transgenic mice were selected.The Cre/loxp system was activated by intraperitoneal injection of tamoxifen (once every other day,three times),and breast β-galactosidase staining was performed 4 weeks after injection.The 8-week-old female Hopx-CreERT2;Rosa26LacZ transgenic mice were selected.The Cre/loxp system was activated by intraperitoneal injection of tamoxifen (once every other day,three times),and breast β-galactosidase staining was performed 4 and 10 weeks after the last injection.(5) Female Hopx-CreERT2;Rosa26LacZ transgenic mice aged 8 weeks were selected.The Cre/loxp system was activated by intraperitoneal injection of tamoxifen (once every other day,three times).Hopx-CreERT2;Rosa26LacZ transgenic mice were pregnant 2 weeks after injection.The mammary tissue of mice at 17.5 days of the first pregnancy and 17.5 days of the third pregnancy was stained with β-galactosidase.RESULTS AND CONCLUSION:(1) The results of β-galactosidase staining showed that the mammary ducts of Hopx-LacZ transgenic mice at 8 weeks of age did contain Hopx-positive cells and were located in the basal epithelia,with a small number.(2) Whole-mount staining of mammary glands and immunofluorescence staining results exhibited that the mammary glands of mice had different characteristics with corresponding developmental stages such as puberty,maturity,and pregnancy,and underwent a series of complex epithelial remodeling processes.(3) The results of β-galactosylase staining showed that Hopx-labeled positive cells in the mammary duct of Hopx-CreERT2;Rosa26LacZ transgenic mice at 17.5 days of gestation increased compared with female Hopx-CreERT2;Rosa26LacZ transgenic mice at 8 weeks of age.(4) The results of β-galactosylase staining showed that the Hopx-labeled positive cells in the mammary glands of 4-and 8-week-old female Hopx-CreERT2;Rosa26LacZ transgenic mice after tamoxifen injection were located in the basal epithelium with a small number.(5) The results of β-galactosidase staining showed that Hopx-labeled positive cells in the mammary glands of mice at 17.5 days of the first and third gestation were located in the basal epithelia around the alveoli,and the number of Hopx-labeled positive cells at 17.5 days of the third gestation was more.(6) In conclusion,Hopx reporter-marked basal epithelial cells belong to dormant mammary stem cells,which are responsible for the growth of the mammary glands during pregnancy and contribute to acinar formation.

Objective To explore the failure criterion that can accurately simulate the tensile and compressive fracture of hollow cortical bone structure.Methods Based on the previous compression and bending experimental data,the predicted results using different failure criteria were compared to determine the simulation accuracy.Results Under the compressive load,the differences in the fracture load between the simulations using the equivalent and invariant strain failure criteria and the experiment were less than 5％,indicating that these two failure criteria were suitable for predicting the cortical bone failure;under the bending load,the differences in the fracture load between the simulations using the equivalent and invariant strain failure criteria and the experiment were less than 5％,indicating that these two failure criteria could accurately predict the failure process.Conclusions The prediction accuracy using different failure criteria mainly depends on whether the strain growth rate conforms to the actual bone deformation.Too fast or too low strain growth rate will lead to premature or delayed structural fracture.The fracture simulation adopted in this study is suitable for most cortical bone structures,and can be used to determine the suitable failure criterion under different loads,so as to assist in obtaining the strength limit of cortical bone in various parts and provide data support for improving the simulation accuracy and grasping the condition of fracture occurrence in clinical practice.

In order to establish a highly efficient,convenient,and effective circular RNA(circRNA)vaccine preparation system,enhanced green fluorescent protein(EGFP)circRNA was constructed using permuted intron exon(PIE)strategy based on type Ⅰ introns.Then,circRNA circularization rates of RNA after in vitro transcription(IVT),primary circularization(IVC1),and secondary circularization(IVC2)were compared after purification.The constructed circRNA system was fur-ther applied to porcine reproductive and respiratory syndrome virus(PRRSV),and two circRNAs based on PRRSV GP5 protein were constructed and developed for in vitro expression.Results showed that circularization rates and protein expression effects of EGFP circRNA in IVC1 RNA and IVC2 RNA were similar,but both were significantly better than those of IVT RNA.Purity of EGFP circRNA reached 74％,and purities of two PRRSV GP5 protein circRNAs constructed using this preparation system were 71％and 64％,respectively.Western blot and indirect immunofluo-rescence assay(IFA)results indicated that both of the PRRSV GP5 protein circRNAs were suc-cessfully expressed.The results demonstrated that an easy-to-operate,low-cost circRNA prepara-tion system with high circularization rate was successfully constructed.Two PRRSV GP5 protein circRNA vaccines were successfully prepared using this system and expressed efficiently,which provides a reference for the development of animal circRNA vaccines and novel candidate vaccines against PRRSV.

In order to establish a highly efficient,convenient,and effective circular RNA(circRNA)vaccine preparation system,enhanced green fluorescent protein(EGFP)circRNA was constructed using permuted intron exon(PIE)strategy based on type Ⅰ introns.Then,circRNA circularization rates of RNA after in vitro transcription(IVT),primary circularization(IVC1),and secondary circularization(IVC2)were compared after purification.The constructed circRNA system was fur-ther applied to porcine reproductive and respiratory syndrome virus(PRRSV),and two circRNAs based on PRRSV GP5 protein were constructed and developed for in vitro expression.Results showed that circularization rates and protein expression effects of EGFP circRNA in IVC1 RNA and IVC2 RNA were similar,but both were significantly better than those of IVT RNA.Purity of EGFP circRNA reached 74％,and purities of two PRRSV GP5 protein circRNAs constructed using this preparation system were 71％and 64％,respectively.Western blot and indirect immunofluo-rescence assay(IFA)results indicated that both of the PRRSV GP5 protein circRNAs were suc-cessfully expressed.The results demonstrated that an easy-to-operate,low-cost circRNA prepara-tion system with high circularization rate was successfully constructed.Two PRRSV GP5 protein circRNA vaccines were successfully prepared using this system and expressed efficiently,which provides a reference for the development of animal circRNA vaccines and novel candidate vaccines against PRRSV.

BACKGROUND:Mammary stem cells are vital for the development and homeostasis of mammary gland tissue.The occurrence of breast cancer has a close relationship with the mammary stem cells.Recent studies have shown that Hopx,as an important transcriptional regulator of morphogenesis and cell differentiation,has been confirmed to be expressed in a variety of adult stem cells such as nerves,intestines,hair follicles and lungs.However,its role in mammary stem cells has not been reported so far.OBJECTIVE:To investigate whether Hopx expression marks mammary stem cells.METHODS:(1) Female Hopx-LacZ transgenic mice aged 8 weeks were selected to detect the background expression of Hopx in breast tissue by β-galactosidase staining.(2) Female wild-type mice at 4,6,and 8 weeks of age and 14.5 days of gestation were selected for whole-tissue magenta staining and K14 and K8 immunofluorescence staining,respectively.(3) Female Hopx-CreERT2;Rosa26LacZ transgenic mice aged 8 weeks and 17.5 days of gestation were selected and stained with breast β-galactosidase.(4) The 4-week-old female Hopx-CreERT2;Rosa26LacZ transgenic mice were selected.The Cre/loxp system was activated by intraperitoneal injection of tamoxifen (once every other day,three times),and breast β-galactosidase staining was performed 4 weeks after injection.The 8-week-old female Hopx-CreERT2;Rosa26LacZ transgenic mice were selected.The Cre/loxp system was activated by intraperitoneal injection of tamoxifen (once every other day,three times),and breast β-galactosidase staining was performed 4 and 10 weeks after the last injection.(5) Female Hopx-CreERT2;Rosa26LacZ transgenic mice aged 8 weeks were selected.The Cre/loxp system was activated by intraperitoneal injection of tamoxifen (once every other day,three times).Hopx-CreERT2;Rosa26LacZ transgenic mice were pregnant 2 weeks after injection.The mammary tissue of mice at 17.5 days of the first pregnancy and 17.5 days of the third pregnancy was stained with β-galactosidase.RESULTS AND CONCLUSION:(1) The results of β-galactosidase staining showed that the mammary ducts of Hopx-LacZ transgenic mice at 8 weeks of age did contain Hopx-positive cells and were located in the basal epithelia,with a small number.(2) Whole-mount staining of mammary glands and immunofluorescence staining results exhibited that the mammary glands of mice had different characteristics with corresponding developmental stages such as puberty,maturity,and pregnancy,and underwent a series of complex epithelial remodeling processes.(3) The results of β-galactosylase staining showed that Hopx-labeled positive cells in the mammary duct of Hopx-CreERT2;Rosa26LacZ transgenic mice at 17.5 days of gestation increased compared with female Hopx-CreERT2;Rosa26LacZ transgenic mice at 8 weeks of age.(4) The results of β-galactosylase staining showed that the Hopx-labeled positive cells in the mammary glands of 4-and 8-week-old female Hopx-CreERT2;Rosa26LacZ transgenic mice after tamoxifen injection were located in the basal epithelium with a small number.(5) The results of β-galactosidase staining showed that Hopx-labeled positive cells in the mammary glands of mice at 17.5 days of the first and third gestation were located in the basal epithelia around the alveoli,and the number of Hopx-labeled positive cells at 17.5 days of the third gestation was more.(6) In conclusion,Hopx reporter-marked basal epithelial cells belong to dormant mammary stem cells,which are responsible for the growth of the mammary glands during pregnancy and contribute to acinar formation.

Objective To explore the failure criterion that can accurately simulate the tensile and compressive fracture of hollow cortical bone structure.Methods Based on the previous compression and bending experimental data,the predicted results using different failure criteria were compared to determine the simulation accuracy.Results Under the compressive load,the differences in the fracture load between the simulations using the equivalent and invariant strain failure criteria and the experiment were less than 5％,indicating that these two failure criteria were suitable for predicting the cortical bone failure;under the bending load,the differences in the fracture load between the simulations using the equivalent and invariant strain failure criteria and the experiment were less than 5％,indicating that these two failure criteria could accurately predict the failure process.Conclusions The prediction accuracy using different failure criteria mainly depends on whether the strain growth rate conforms to the actual bone deformation.Too fast or too low strain growth rate will lead to premature or delayed structural fracture.The fracture simulation adopted in this study is suitable for most cortical bone structures,and can be used to determine the suitable failure criterion under different loads,so as to assist in obtaining the strength limit of cortical bone in various parts and provide data support for improving the simulation accuracy and grasping the condition of fracture occurrence in clinical practice.