BACKGROUND:Aging of human body may be due to the senescence and depletion of various stem cells in the body.Bone marrow mesenchymal stromal cells have important physiological functions and have shown certain therapeutic effects on various diseases.It is of great significance to study the senescence and mechanism of bone marrow mesenchymal stromal cells.OBJECTIVE:To investigate whether human bone marrow mesenchymal stromal cells exhibit senescence phenotypes with increasing donor age,and further determine whether endogenous retrovirus drives the senescence of bone marrow mesenchymal stromal cells,offering a novel reference for the investigation of stem cell senescence mechanism.METHODS:The senescence of bone marrow mesenchymal stromal cells at different ages was characterized by flow cytometry,β-galactosidase staining,qPCR,western blotting,and EdU fluorescence imaging.Bone marrow mesenchymal stromal cells and cell culture supernatant were collected from donors of different ages.The content of human endogenous retrovirus was detected by qPCR.Furthermore,highly sensitive droplet digital PCR was used to detect the expression of endogenous retrovirus-like particles in the cell culture supernatant.The content of endogenous retrovirus in bone marrow plasma samples of different ages was detected by ELISA.RESULTS AND CONCLUSION:Bone marrow mesenchymal stromal cells exhibited obvious senescence with increasing age,including significant morphological changes,increased proportion of β-galactosidase positive cells,increased expression of senescence markers P16 and P21 protein,decreased expression of LMNB1 protein,and reduced cell proliferation ability.There was no significant difference in the content of endogenous retrovirus in bone marrow mesenchymal stromal cells at different ages,almost no endogenous retrovirus-like particles in the cell culture supernatant.There was no significant difference in endogenous retrovirus-like particles detected in bone marrow plasma samples at different ages.These findings indicate that human bone marrow mesenchymal stromal cells have normal physiological senescence with increasing age,but the mechanism of senescence is not mediated by abnormal activation of endogenous retroviruses,which may have a more complex driving mechanism.

BACKGROUND:Aging of human body may be due to the senescence and depletion of various stem cells in the body.Bone marrow mesenchymal stromal cells have important physiological functions and have shown certain therapeutic effects on various diseases.It is of great significance to study the senescence and mechanism of bone marrow mesenchymal stromal cells.OBJECTIVE:To investigate whether human bone marrow mesenchymal stromal cells exhibit senescence phenotypes with increasing donor age,and further determine whether endogenous retrovirus drives the senescence of bone marrow mesenchymal stromal cells,offering a novel reference for the investigation of stem cell senescence mechanism.METHODS:The senescence of bone marrow mesenchymal stromal cells at different ages was characterized by flow cytometry,β-galactosidase staining,qPCR,western blotting,and EdU fluorescence imaging.Bone marrow mesenchymal stromal cells and cell culture supernatant were collected from donors of different ages.The content of human endogenous retrovirus was detected by qPCR.Furthermore,highly sensitive droplet digital PCR was used to detect the expression of endogenous retrovirus-like particles in the cell culture supernatant.The content of endogenous retrovirus in bone marrow plasma samples of different ages was detected by ELISA.RESULTS AND CONCLUSION:Bone marrow mesenchymal stromal cells exhibited obvious senescence with increasing age,including significant morphological changes,increased proportion of β-galactosidase positive cells,increased expression of senescence markers P16 and P21 protein,decreased expression of LMNB1 protein,and reduced cell proliferation ability.There was no significant difference in the content of endogenous retrovirus in bone marrow mesenchymal stromal cells at different ages,almost no endogenous retrovirus-like particles in the cell culture supernatant.There was no significant difference in endogenous retrovirus-like particles detected in bone marrow plasma samples at different ages.These findings indicate that human bone marrow mesenchymal stromal cells have normal physiological senescence with increasing age,but the mechanism of senescence is not mediated by abnormal activation of endogenous retroviruses,which may have a more complex driving mechanism.

Objective: To analyze the change trends in the body shape indicators and proportions of students in Harbin from 2010 to 2024, and to investigate ergonomic compatibility of functional dimensions of school desks and chairs with current student shape indicators, so as to provide a reference for revising furniture standards of desks and chairs. Methods: Between September and November of both 2010 and 2024, a combination of convenience sampling and stratified cluster random sampling was conducted across three districts in Harbin, yielding samples of 6 590 and 6 252 students, respectively. Anthropometric shape indicators cluding height, sitting height, crus length, and thigh length-and their proportional changes were compared over the 15-year period. The 2024 data were compared with current standard functional dimensions of school furniture. The statistical analysis incorporated t-test and Mann-Whitney U- test. Results: From 2010 to 2024, average height increased by 1.8 cm for boys and 1.5 cm for girls; sitting height increased by 1.5 cm for both genders; crus length increased by 0.3 cm for boys and 0.4 cm for girls; and thigh length increased by 0.5 cm for both genders. The ratios of sitting height to height, and sitting height to leg length increased by less than 0.1 . The difference between desk chair height and 1/3 sitting height ranged from 0.4-0.8 cm. Among students matched with size 0 desks and chairs, 22.0% had a desk to chair height difference less than 0, indicating that the desk to chair height difference might be insufficient for taller students. The differences between seat height and fibular height ranged from -1.4 to 1.1 cm; and the differences between seat depth and buttock popliteal length ranged from -9.8 to 3.4 cm. Among obese students, the differences between seat width and 1/2 hip circumference ranged from -20.5 to -8.7 cm, while it ranged from -12.2 to -3.8 cm among non obese students. Conclusion Current furniture standards basically satisfy hygienic requirements; however, in the case of exceptionally tall and obese students, ergonomic accommodations such as adaptive seating allocation or personalized adjustments are recommended to meet hygienic requirements.

BackgroundDepression has become a public health concern that affects the physical and mental health of college students. acute stress response is a risk factor of depression. Exploring the relationship and mechanism between acute stress response and depression is of great significance for preventing and intervening depression in college students. ObjectiveTo examine the relationship between acute stress response and depression among college students， and to analyze the mediating role of rumination and the moderated effect of perceived social support， so as to provide references for the prevention and intervention of depression in college student . MethodsFrom March to April 2020， a cluster sampling method was employed to select 1 355 college students from three universities in Hubei， Jiangxi and Guangxi Zhuang Autonomous Region. Participants were assessed with Acute Stress Disorder Scale （ASDS）， Ruminative Responses Scale （RRS）， Brief form of Perceived Social Support Questionnaire （F-SozU） and Patients' Health Questionnaire Depression Scale-9 item （PHQ-9）. Pearson correlation analysis was adopted to examine the correlation between the scores of each scale. The mediating role of rumination between acute stress response and depression and the moderated role of perceived social support were examined respectively by using Model 4 and Model 14 in Macro Program Process 3.3. ResultsA total of 1 303 valid questionnaires were collected， yielding a valid response rate of 96.16%. The results of Pearson correlation analysis showed that ASDS score was positively correlated with RRS score and PHQ-9 score （r=0.649， 0.528， P<0.01） among college students. The mediation analysis results demonstrated that rumination played a partial mediating role between acute stress response and depression， with the mediating effect value of 0.273 （95% CI：0.222~0.328）， accounting for 68.59% of the total effect. Perceived social support played a moderated role in the latter path of the mediation model （rumination → depression） （β=-0.004， 95% CI： -0.017~-0.004， P<0.01）. ConclusionRumination played a partial mediating role between acute stress response and depression in college students， and perceptive social support played a moderated role between rumination and depression. ［Funded by Scientific Research Fund Project of Education Department of Yunnan Province （number， 2025J0437）］

BACKGROUND: The contraction behaviors of cardiomyocytes (CMs), especially contraction synchrony, are crucial factors reflecting their maturity and response to drugs. A wider field of view helps to observe more pronounced synchrony differences, but the accompanied greater computational load, requiring more computing power or longer computational time. METHODS: We proposed a method that directly correlates variations in optical field brightness with cardiac tissue contraction status (CVB method), based on principles from physics and photometry, for rapid video analysis in wide field of view to obtain contraction parameters, such as period and contraction propagation direction and speed. RESULTS: Through video analysis of human induced pluripotent stem cell (hiPSC)-derived CMs labeled with green fluorescent protein (GFP) cultured on aligned and random nanofiber scaffolds, the CVB method was demonstrated to obtain contraction parameters and quantify the direction and speed of contraction within regions of interest (ROIs) in wide field of view. The CVB method required less computation time compared to one of the contour tracking methods, the LucasKanade (LK) optical flow method, and provided better stability and accuracy in the results. CONCLUSION This method has a smaller computational load, is less affected by motion blur and out-of-focus conditions, and provides a potential tool for accurate and rapid analysis of cardiac tissue contraction synchrony in wide field of view without the need for more powerful hardware.

BACKGROUND: The contraction behaviors of cardiomyocytes (CMs), especially contraction synchrony, are crucial factors reflecting their maturity and response to drugs. A wider field of view helps to observe more pronounced synchrony differences, but the accompanied greater computational load, requiring more computing power or longer computational time. METHODS: We proposed a method that directly correlates variations in optical field brightness with cardiac tissue contraction status (CVB method), based on principles from physics and photometry, for rapid video analysis in wide field of view to obtain contraction parameters, such as period and contraction propagation direction and speed. RESULTS: Through video analysis of human induced pluripotent stem cell (hiPSC)-derived CMs labeled with green fluorescent protein (GFP) cultured on aligned and random nanofiber scaffolds, the CVB method was demonstrated to obtain contraction parameters and quantify the direction and speed of contraction within regions of interest (ROIs) in wide field of view. The CVB method required less computation time compared to one of the contour tracking methods, the LucasKanade (LK) optical flow method, and provided better stability and accuracy in the results. CONCLUSION This method has a smaller computational load, is less affected by motion blur and out-of-focus conditions, and provides a potential tool for accurate and rapid analysis of cardiac tissue contraction synchrony in wide field of view without the need for more powerful hardware.

Objective To systematically evaluate the risk prediction models for anastomotic leakage (AL) in patients with esophageal cancer after surgery. Methods A computer-based search of PubMed, EMbase, Web of Science, Cochrane Library, Chinese Medical Journal Full-text Database, VIP, Wanfang, SinoMed and CNKI was conducted to collect studies on postoperative AL risk prediction model for esophageal cancer from their inception to October 1st, 2023. PROBAST tool was employed to evaluate the bias risk and applicability of the model, and Stata 15 software was utilized for meta-analysis. Results A total of 19 literatures were included covering 25 AL risk prediction models and 7373 patients. The area under the receiver operating characteristic curve (AUC) was 0.670-0.960. Among them, 23 prediction models had a good prediction performance (AUC>0.7); 13 models were tested for calibration of the model; 1 model was externally validated, and 10 models were internally validated. Meta-analysis showed that hypoproteinemia (OR=9.362), postoperative pulmonary complications (OR=7.427), poor incision healing (OR=5.330), anastomosis type (OR=2.965), preoperative history of thoracoabdominal surgery (OR=3.181), preoperative diabetes mellitus (OR=2.445), preoperative cardiovascular disease (OR=3.260), preoperative neoadjuvant therapy (OR=2.977), preoperative respiratory disease (OR=4.744), surgery method (OR=4.312), American Society of Anesthesiologists score (OR=2.424) were predictors for AL after esophageal cancer surgery. Conclusion At present, the prediction model of AL risk in patients with esophageal cancer after surgery is in the development stage, and the overall research quality needs to be improved.

Laccase is a type of polyphenol oxidase that can catalyze the oxidation of various substances,including phenols,aromatic amines,and catecholamines.It has been widely utilized in pollutant degradation and analytical applications.However,the high cost of preparation of natural laccase and its susceptibility to environmental factors,which can lead to denaturation and inactivation,limit its practical applications.Nanozymes,which are nanomaterials that exhibit enzyme-like properties,offer advantages such as easy preparation,adjustable activity,and exceptional stability.Currently,many types of nanozymes have been developed.Inspired by the coordination of Cu2+with amino acids in the active site of natural laccase,researchers have employed coordination synthetic strategies to prepare laccase-like nanozymes.The metal nodes in these laccase-like nanozymes include copper,manganese,and cerium,while the ligands involve a variety of chemicals like nucleotides,amino acids,polypeptides,and aromatic acids.By manipulating factors such as the metal-to-ligand ratio,reducing capacity of ligands,buffer solutions,chloride ions,bromine ions,the catalytic activity of laccase-like nanozymes can be finely tuned.In this paper,laccase-like nanozymes developed through coordination strategies were categorized and summarized,along with review of their analytical applications in detection of phenolic compounds,disease biomarkers,antibiotics,pesticides,sulfur-containing pollutants,and time-temperature indicators.Furthermore,the challenges currently faced in the research of laccase-like nanozymes and future research directions were discussed.

Poly(lactic-co-glycolide)(PLGA)is a key excipient in long-acting sustained-release preparations,and its degradation properties directly affect the drug release behavior.In this study,PLGA microspheres were prepared by microfluidic techniques,and the morphology changes of the microspheres were observed by scanning electron microscopy(SEM).In alkaline environment,due to the accelerated hydrolysis of ester bonds,the surface of the microspheres was rapidly dissolved and eroded,and the degradation rate was significantly higher than that in acidic environment.High temperature accelerated the degradation of PLGA microspheres.Under neutral and alkaline conditions,the microspheres showed aggregation and adhesion.Under acidic conditions,the microspheres gradually decomposed into irregular fragments.The high ionic strength further promoted the surface corrosion of the microspheres,especially under extreme pH conditions.Simultaneously,PLGA microspheres encapsulating coumarin were prepared to simulate the microsphere formulation.The release rate of coumarin after degradation of the microspheres under different conditions was observed by measuring the absorbance with ultraviolet-visible spectrophotometry.The results were consistent with those of the blank microspheres.This study revealed that the degradation of PLGA microspheres was significantly pH-dependent,temperature sensitive and ion strength responsive.These findings not only helped to understand and optimize the long-term stability and controlled release performance of drug-carrying microspheres,but also provided a theoretical basis for further improvement of PLGA-based drug carrier design.

Objective To investigate the relationship between serum microRNA(miRNA,miR)-9-5p,miR-21-5p and miR-206 and hemorrhagic transformation(HT)occurs and prognosis in patients with large ar-tery atherosclerotic cerebral infarction(ACI-LAA)after thrombolysis.Methods A total of 265 patients with ACI-LAA admitted to the hospital from April 2021 to November 2023 were selected as the research objects.According to whether HT occurred after intravenous thrombolysis,they were divided into non-HT group and HT group,and the expression levels of serum miR-9-5p,miR-21-5p and miR-206 were compared between the two groups.The general data of patients with ACI-LAA were collected.Univariate and multivariate Logistic regression analysis were used to analyze the influencing factors of HT occurs in patients with ACI-LAA after thrombolysis.The receiver operating characteristic(ROC)curve was used to analyze the efficacy of serum miR-9-5p,miR-21-5p and miR-206 expression levels in predicting HT occurs after thrombolysis in patients with ACI-LAA.The patients with ACI-LAA were followed up for 90 d.According to the modified Rankin scale(mRS)score,the patients were divided into a good prognosis group and a poor prognosis group,and the expression levels of serum miR-9-5p,miR-21-5p and miR-206 were compared between the two groups.Univa-riate and multivariate Logistic regression analysis were used to analyze the influencing factors of poor progno-sis in patients with ACI-LAA.ROC curve was used to analyze the efficacy of serum miR-9-5p,miR-21-5p and miR-206 expression levels in predicting poor prognosis of patients with ACI-LAA.Results HT occurred in 74(27.92％)of 265 patients with ACI-LAA after thrombolysis.Compared with the non-HT group,the National Institutes of Health Stroke Scale(NIHSS)score atadmission,the proportion of hypertension,the proportion of infarct size ≥10 cm2,and the expression levels of serum miR-21-5p and miR-206 were significantly in-creased in the HT group(P＜0.05).However,the expression level of serum miR-9-5p was decreased(P＜0.05).Hypertension,high NIHSS score at admission,the proportion of infarct size ≥10 cm2,high expression of miR-21-5p and miR-206 were risk factors for HT occurs in patients with ACI-LAA after intravenous thrombolysis,and high expression of miR-9-5p was a protective factor(P＜0.05).The ROC curve showed that the area under the curve(AUC)and 95％CI of single and combined detection of serum miR-9-5p,miR-21-5p and miR-206 for predicting HT occurs were 0.796(0.726-0.866),0.779(0.711-0.846),0.784(0.714-0.854),0.891(0.839-0.943),respectively.Among 265 patients with ACI-LAA,83 patients(31.32％)had poor prognosis at 90 d of follow-up.Compared with the good prognosis group,the age,NIHSS score at admis-sion,the proportion of HT,the proportion of infarct size ≥10 cm2,and the expression levels of serum miR-21-5p and miR-206 were increased(P＜0.05),and the expression level of serum miR-9-5p was decreased(P＜0.05)in the poor prognosis group.Advanced age,high NIHSS score at admission,HT,infarct size ≥10 cm2,high expression of miR-21-5p,and high expression of miR-206 were risk factors for poor prognosis of ACI-LAA patients,and high expression of miR-9-5p was a protective factor(P＜0.05).The ROC curve showed that The AUC(95％CI)of single and combined detection of serum miR-9-5p,miR-21-5p and miR-206 for predicting poor prognosis were 0.754(0.691-0.818),0.779(0.719-0.838),0.792(0.815-0.919),0.931(0.902-0.960),respectively.Conclusion Low expression of serum miR-9-5p,high expression of miR-21-5p and high expression of miR-206 are associated with the HT occurs and poor prognosis in patients with ACI-LAA after thrombolysis,and the combined detection of the three indicators has a high predictive value for the HT occurs and poor prognosis.