1.Correlation of childhood trauma and leisure activities with psychological distress among upper grade elemetary school students
Chinese Journal of School Health 2026;47(1):70-74
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.
2.Analyzing Differences in Volatile Components of Citri Reticulatae Pericarpium Before and After Being Stir-fried with Halloysitum Rubrum Based on HS-GC-MS and Intelligent Sensory Technology
Li XIN ; Jiawen WEN ; Wenhui GONG ; Beibei ZHAO ; Shihao YAN ; Huashi CHEN ; Haiping LE ; Jinlian ZHANG ; Yanhua XUE
Chinese Journal of Experimental Traditional Medical Formulae 2025;31(7):157-162
ObjectiveTo analyze the differences in color, odor and volatile components of Citri Reticulatae Pericarpium(CRP) before and after being stir-fried with Halloysitum Rubrum, and to explore the material basis of enhancing the effect of strengthening spleen after processing and the scientific connotation of decoction pieces processed with Halloysitum Rubrum as the auxiliary material. MethodsThe volatile components of the samples before and after processing were identified and relatively quantified by headspace gas chromatography-mass spectrometry(HS-GC-MS), and the volatile components were analyzed by principal component analysis(PCA) and orthogonal partial least squares-discriminant analysis(OPLS-DA). According to the principle of variable importance in the projection(VIP) value>1.5, volatile differential components before and after processing were screened. And combined with intelligent sensory technologies such as colorimeter and electronic nose, the chroma and odor information of CRP before and after being stir-fried with Halloysitum Rubrum were identified. Pearson correlation analysis was used to explore the correlation between volatile differential components and chroma values. ResultsA total of 112 volatile components were identified from CRP and CRP stir-fried with Halloysitum Rubrum, of which 84 were from CRP and 97 were from CRP stir-fried with Halloysitum Rubrum. And 7 differential components were selected, including α-pinene, β-myrcene, linalool, sabinene, ocimene isomer mixture, A-ocimene, and δ-elemene. After being processed with Halloysitum Rubrum, the brightness value(L*), yellow-blue value(b*) and total chromatic value(E*ab) of CRP were decreased(P<0.01), and red-green value(a*) was increased(P<0.01), the response values of S4, S5, S10 and S13 sensors were significantly increased(P<0.05), and the response values of S3 and S8 sensors were significantly decreased(P<0.05). Correlation analysis showed that α-pinene and β-myrcene were negatively correlated with L* and E*ab, but positively correlated with a*. Sabinene was positively correlated with L* and E*ab. Linalool was positively correlated with L* and E*ab, and negatively correlated with a*. The ocimene isomer mixture was positively correlated with the L*. ConclusionAfter being processed with Halloysitum Rubrum, the appearance color, odor and volatile components of CRP change significantly, and α-pinene, β-myrcene, sabinene, linalool and A-ocimene are the characteristic volatile components before and after processing, which can provide references for the quality evaluation and clinical application of CRP and its processed products.
3.Analyzing Differences in Volatile Components of Citri Reticulatae Pericarpium Before and After Being Stir-fried with Halloysitum Rubrum Based on HS-GC-MS and Intelligent Sensory Technology
Li XIN ; Jiawen WEN ; Wenhui GONG ; Beibei ZHAO ; Shihao YAN ; Huashi CHEN ; Haiping LE ; Jinlian ZHANG ; Yanhua XUE
Chinese Journal of Experimental Traditional Medical Formulae 2025;31(7):157-162
ObjectiveTo analyze the differences in color, odor and volatile components of Citri Reticulatae Pericarpium(CRP) before and after being stir-fried with Halloysitum Rubrum, and to explore the material basis of enhancing the effect of strengthening spleen after processing and the scientific connotation of decoction pieces processed with Halloysitum Rubrum as the auxiliary material. MethodsThe volatile components of the samples before and after processing were identified and relatively quantified by headspace gas chromatography-mass spectrometry(HS-GC-MS), and the volatile components were analyzed by principal component analysis(PCA) and orthogonal partial least squares-discriminant analysis(OPLS-DA). According to the principle of variable importance in the projection(VIP) value>1.5, volatile differential components before and after processing were screened. And combined with intelligent sensory technologies such as colorimeter and electronic nose, the chroma and odor information of CRP before and after being stir-fried with Halloysitum Rubrum were identified. Pearson correlation analysis was used to explore the correlation between volatile differential components and chroma values. ResultsA total of 112 volatile components were identified from CRP and CRP stir-fried with Halloysitum Rubrum, of which 84 were from CRP and 97 were from CRP stir-fried with Halloysitum Rubrum. And 7 differential components were selected, including α-pinene, β-myrcene, linalool, sabinene, ocimene isomer mixture, A-ocimene, and δ-elemene. After being processed with Halloysitum Rubrum, the brightness value(L*), yellow-blue value(b*) and total chromatic value(E*ab) of CRP were decreased(P<0.01), and red-green value(a*) was increased(P<0.01), the response values of S4, S5, S10 and S13 sensors were significantly increased(P<0.05), and the response values of S3 and S8 sensors were significantly decreased(P<0.05). Correlation analysis showed that α-pinene and β-myrcene were negatively correlated with L* and E*ab, but positively correlated with a*. Sabinene was positively correlated with L* and E*ab. Linalool was positively correlated with L* and E*ab, and negatively correlated with a*. The ocimene isomer mixture was positively correlated with the L*. ConclusionAfter being processed with Halloysitum Rubrum, the appearance color, odor and volatile components of CRP change significantly, and α-pinene, β-myrcene, sabinene, linalool and A-ocimene are the characteristic volatile components before and after processing, which can provide references for the quality evaluation and clinical application of CRP and its processed products.
4.Analysis of Changes on Volatile Components of Ligusticum sinense cv. Chaxiong Rhizome Before and After Wine Processing Based on Electronic Nose and HS-GC-MS
Wen ZHANG ; Peng ZHENG ; Jiangshan ZHANG ; Xiaolin XIAO ; Zaodan WU ; Li XIN ; Wenhui GONG ; Jinlian ZHANG
Chinese Journal of Experimental Traditional Medical Formulae 2025;31(2):173-181
ObjectiveBy comparing the composition and content of volatile components in raw products, wine-washed products and wine-fried products of Ligusticum sinense cv. Chaxiong rhizome(LSCR), to investigate the influence of wine processing on the volatile components of LSCR, in order to provide a basis for the development of quality standards for LSCR and its processed products. MethodsElectronic nose was used to identify the odors of LSCR, wine-washed and wine-fried LSCR, and their volatile components were detected by headspace gas chromatography-mass spectrometry(HS-GC-MS), and the relative mass fractions of these components were determined by peak area normalization method. Principal component analysis(PCA) and orthogonal partial least squares-discriminant analysis(OPLS-DA) were performed on the obtained sample data by SIMCA 14.1 software, and the differential components of LSCR, wine-washed and wine-fried LSCR were screened according to the variable importance in the projection(VIP) value>1. Pearson correlation analysis was used to explore the relationship between volatile differential flavor components and electronic nose sensors. ResultsElectronic nose detection results showed that there were significant differences in the odors of LSCR, wine-washed and wine-fried LSCR, mainly reflected in the sensors S2, S4, S5, S6, S11, S12, S13. And a total of 62 compounds were identified from LSCR and its wine-processed products, among which 46, 50 and 51 compounds were identified from LSCR, wine-fried and wine-washed LSCR, respectively. There were 21 differential components between the raw products and wine-fried products, of which 10 components were increased and 11 were decreased after processing. There were 20 differential components between the raw products and wine-washed products, of which 11 constituents increased and 9 decreased after processing. There were 17 differential components between the wine-wash products and wine-fried products. Compared with the wine-washed products, the contents of 13 components in the wine-fried products increased, and the contents of 4 components decreased. The increasing trend of the content of phthalides in the wine-washed products was more obvious than that in the wine-fried products, but the content of total volatile components was higher in the wine-fried products than the wine-washed products. Correlation analysis showed that there were different degrees of correlation between the 7 differential sensors of electronic nose and 24 differential volatile components, mainly phthalides and olefins. ConclusionThe odor and the content of volatile components in LSCR changed obviously after wine processing, and n-butylphthalide, Z-butylidenephthalide and E-ligustilide can be used as the candidate differential markers of volatile components in LSCR before and after wine processing.
5.Expression of OLFML2A in acute leukemia patients and its diagnostic and prognostic evaluation value
Yao HE ; Jinlian LI ; Xuan LU ; Wanchuan ZHUANG ; Xingxing CHAI
Journal of Leukemia & Lymphoma 2025;34(2):73-79
Objective:To investigate the transcriptional level expression of olfactomedin-like protein 2A (OLFML2A) in peripheral blood of patients with acute leukemia (AL) and its diagnostic and prognostic evaluation value.Methods:A retrospective cohort study was conducted. A total of 34 patients with AL (AL group) admitted to the Second People's Hospital of Lianyungang from January 2019 to March 2023 were selected, including 26 cases of acute myeloid leukemia (AML) (non-acute promyelocytic leukemia) and 8 cases of acute lymphoblastic leukemia (ALL). Another 15 healthy subjects who underwent the physical examination during the same period were selected as the healthy control group. Among 26 patients with AML, 18 were males and 8 were females. The median age [ M (IQR)] was 59 (9) years; 5 cases relapsed. Among 8 patients with ALL, 4 were males and 4 were females. The median age was 48 (12) years; 1 case relapsed. Real-time fluorescence quantitative polymerase chain reaction (qPCR) medthod was used to detect the relative expression level of OLFML2A mRNA in peripheral blood of each group. The relative expression levels of OLFML2A mRNA among the different patients stratified by clinicopathological factors were compared. Taking bone marrow smear cytology or bone marrow biopsy as the gold standard, receiver operating characteristic (ROC) curve was used to analyze the diagnostic effect of the relative expression level of OLFML2A mRNA on AML and ALL. According to the median relative expression level of OLFML2A mRNA in AL patients, the patients were divided into the high expression of OLFML2A mRNA (≥ the median) and the low expression of OLFML2A mRNA (< the median) groups. Progression-free survival (PFS) and overall survival (OS) of both groups were analyzed by using Kaplan-Meier curve. The log-rank test was used for comparison between groups. Results:The median relative expression level of OLFML2A mRNA in AL group was higher than that in the healthy control group [3.53 (8.19) vs. 0.27 (0.23)], and the difference was statistically significant ( Z = 4.38, P < 0.001). The median relative expression level of OLFML2A mRNA in AML group was higher than that in ALL group [4.92, (9.80) vs. 1.60 (4.35)], which were higher than that in the healthy control group; and the differences were statistically significant (all P < 0.05). There were statistically significant differences in the relative expression level of OLFML2A mRNA among AML patients with different prognosis risk stratification, fusion gene positive or not, whether there was chromosome abnormality, and whether the average daily hospitalization cost was < 2 500 yuan (all P < 0.05). There were statistically significant differences in the relative expression level of OLFML2A mRNA among ALL patients with different prognostic risk stratification, whether there was fusion gene and whether there was chromosome abnormality (all P < 0.05). ROC curve analysis showed that the area under the curve for the diagnosis of AML based on the relative expression level of OLFML2A mRNA was 0.936 (95% CI: 0.862-1.000), and the optimal cut-off value was 0.780; the area under the curve for the diagnosis ALL was 0.767 (95% CI: 0.535-0.998), and the optimal cut-off value was 0.558. Kaplan-Meier survival curve analysis showed that the 3-year PSF rate in AL patients with high expression of OLFML2A mRNA (17 cases) and low expression of OLFML2A mRNA was 20.5% and 30.6%, respectively, and PFS in AL patients with low expression of OLFML2A mRNA was superior to those with high expression, and the difference was statistically significant ( χ2 = 4.64, P = 0.031). The 3-year OS rates in AL patients with high and low expression of OLFML2A mRNA was 40.4% and 33.3%, respectively, and there was no statistically significant difference in OS between the 2 groups ( χ2 = 1.55, P = 0.213). Conclusions:The relative expression level of OLFML2A mRNA is high in AL patients, and it is more significant in AML patients. The level of OLFML2A gene has a certain value in the diagnostic and prognostic evaluation of AL.
6.The SIRT6 gene promotes the anti-aging effects of mesenchymal stem cells in dogs.
Dongyao HAN ; Balun LI ; Miao HAN ; Hongkai TIAN ; Jiaqi GAO ; Zengyu ZHANG ; Zixi LING ; Na LI ; Jinlian HUA
Chinese Journal of Biotechnology 2025;41(7):2719-2734
Mesenchymal stem cells (MSCs) are an effective therapeutic strategy to delay aging in dogs, they are prone to aging and have poor genetic stability when cultured for a long time in vitro. Therefore, it is of great significance to explore a method to improve the anti-aging ability of MSCs. Previous studies have shown that sirtuin 6 (SIRT6) plays an important role in anti-aging. This study constructed MSCs with overexpressed SIRT6 gene. Through Giemsa staining and senescence-associated β-galactosidase staining, it was found that SIRT6 significantly enhances the anti-aging capacity of MSCs. Transmission electron microscopy imaging and the detection of oxidative stress-related indicators revealed that SIRT6 improves the anti-aging capacity of MSCs by maintaining mitochondrial homeostasis and reducing oxidative stress levels. Transcriptome sequencing analysis revealed that SIRT6 mainly acted on phosphatidylinositol-3-kinase, mitogen-activated protein kinase and other aging and inflammation related pathways. In the establishment and verification of aging models in mice and dogs, it was found that the spatial memory ability of the model mice was significantly increased after intravenous transplantation of SIRT6 overexpression cells, the organ index was also significantly changed, and the anti-oxidative capacity of the dogs and mice blood was improved. The morphology of the spleens and livers in the SIRT6 overexpression cell treatment group could be effectively restored, and the expression levels of aging and inflammation-related proteins were significantly decreased. This study provides a new idea for the study of SIRT6-mediated anti-aging of MSCs.
Animals
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Dogs
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Mesenchymal Stem Cells/metabolism*
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Sirtuins/genetics*
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Aging/physiology*
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Mice
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Oxidative Stress
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Mesenchymal Stem Cell Transplantation
7.Cathepsins and osteonecrosis:analysis based on European samples from the FinnGen Database and IEU OpenGWAS Database
Jinlian CHAI ; Tiefeng SUN ; Wei LI ; Bochun ZHANG ; Guangzheng LI ; Xuekun SHAO ; Ping WANG ; Xuezhen LIANG
Chinese Journal of Tissue Engineering Research 2025;29(24):5254-5262
BACKGROUND:Osteonecrosis is an orthopedic disease that severely limits joint function,with complex pathogenesis involving multiple risk factors.Cathepsins,as a class of enzymes that play a key role in bone metabolism,are closely related to the proliferation,differentiation of bone cells,and remodeling of the bone matrix.However,previous studies have mostly focused on descriptive analyses,lacking direct evidence of causal relationships.OBJECTIVE:To clarify the potential causal relationship between cathepsins and osteonecrosis and to explore their possible mechanisms by analyzing large-scale sample data from the FinnGen database.METHODS:We obtained osteonecrosis-related data from the FinnGen database,including R9(a total of 359 399 samples:1 385 cases and 358 014 controls)and R10 versions(a total of 392 580 samples:1 543 cases and 391 037 controls).Single nucleotide polymorphisms associated with nine cathepsins(cathepsin B,E,F,G,H,O,S,L2,and Z)were acquired from a previous study(3 301 individuals).Univariate Mendelian randomization,reverse univariate Mendelian randomization,and multivariate Mendelian randomization analyses were conducted using the inverse variance weighted method,MR-Egger method,weighted median method,simple mode method,and weighted mode method.Initially,Mendelian randomization analysis was performed using osteonecrosis data from R9.Additionally,sensitivity analyses were conducted using Cochran's Q test,MR-Egger intercept,MR-PRESSO global test,and leave-one-out analysis to check for horizontal pleiotropy and heterogeneity.Subsequently,a validation analysis study was carried out on the R10 dataset,and a meta-analysis was conducted to combine the two datasets to explore the joint effect.RESULTS AND CONCLUSION:Univariate Mendelian randomization analysis results showed that higher levels of cathepsin B were significantly associated with a reduced risk of osteonecrosis(inverse variance weighted:odds ratio(OR)=0.865,95%confidence interval(CI):0.762-0.982,P=0.025),and no reverse causal relationship was found between the nine cathepsins and osteonecrosis(P>0.05).These associations were validated by meta-analysis.Multivariate analysis,using the nine cathepsins as covariates,revealed a reverse causal relationship between the levels of cathepsin Band the risk of osteonecrosis(inverse variance weighted:OR=0.8710,95%CI:0.761-0.997,P=0.045),consistent with the results before adjustment.Sensitivity analyses based on heterogeneity and horizontal pleiotropy suggested that the results were relatively robust.This study suggests that there is a causal relationship between high levels of cathepsin B and the reduced risk of osteonecrosis,and it may serve as a biomarker for osteonecrosis,providing new directions and insights for the diagnosis and treatment of osteonecrosis.Although this study is based on data analysis of European populations,these findings have important implications for Chinese biomedical research,especially in understanding disease mechanisms,developing biomarkers,and formulating treatment strategies.They also encourage similar studies conducted on Chinese populations to explore the impact of racial and genetic background differences on the occurrence of osteonecrosis.
8.Study of current situations of economic toxicity and associated factors in hematological malignancies patients
Jinlian LI ; Yaping HUANG ; Zijin WU ; Lingling TIAN ; Chupin CEN ; Shan HUANG
China Modern Doctor 2025;63(11):35-38
Objective To investigate the current situations of economic toxicity in hematological malignancies patients,and explore it's correlation with quality of life and psychological resilience.Methods A total of 135 hematological malignancies patients admitted in Sun Yat-sen Memorial Hospital,Sun Yat-sen University from December 2022 to October 2023 were selected as subjects.Patients were surveyed by using general information and disease-related information questionnaires,comprehensive scores for financial toxicity,European organization for research and treatment of cancer core questionnaire,connor-davidson resilience scale,social support rating sale.Correlation analysis was performed by using the Pearson method.Multiple linear regression was used to analyze the factors of economic toxicity after controlling for confounding factors.Results Economic toxicity score of 135 hematological malignancies patients was(15.95±0.84)points,of which 82.2%of them had economic toxicity.It was positively correlated with functional quality of life(r-0.464,P=<0.001)and psychological resilience(r=0.232,P=0.007),and negatively correlated with symptomatic psychological quality(r=-0.440,P<0.001).Multiple linear regression analysis showed that quality of life,knowledge of the treatment cost,course of treatment,patient personality and have no second caregiver were influencing factors of economic toxicity of hematological malignancies(P<0.05).Conclusion Hematological malignancies patients have a higher level of economic toxicity,which can affect their quality of life and psychological resilience.
9.Therapeutic effect of Cornus Cervi Colla on steroid-induced osteonecrosis of the femoral head in rat models:fecal metabolomics analysis
Jinlian CHAI ; Tiefeng SUN ; Wei LI ; Bochun ZHANG ; Guangzheng LI ; Zhongqi ZHOU ; Xuezhen LIANG ; Ping WANG
Chinese Journal of Tissue Engineering Research 2025;29(29):6187-6197
BACKGROUND:Previous studies by the research group have shown that core proteoglycan in Cornus Cervi Col la can enter the bone,promote the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells,and has a good repair effect on steroid-induced osteonecrosis of the femoral head.OBJECTIVE:To investigate the therapeutic effect and potential mechanism of Cornus Cervi Colla on steroid-induced osteonecrosis of the femoral head in rats by fecal non-targeted fecal metabolomics.METHODS:Thirty SD rats were randomly divided into three groups using a random number table method:the control group(n=10)was injected with normal saline into the right gluteal muscle(injected on the first 3 days of each week for 3 consecutive weeks),and was given pure water gavage(once a day for 6 consecutive weeks).The model group(n=10)was injected with methylprednisolone sodium succinate into the right gluteal muscle(injected on the first 3 days of each week for 3 consecutive weeks)to establish a steroid-induced osteonecrosis of the femoral head model,and was given pure water gavage(once a day for 6 consecutive weeks).The Cornus Cervi Co I la group(n=10)was also established with a steroid-induced osteonecrosis of the femoral head model,and was given Cornus Cervi Col la gavage(once a day for 6 consecutive weeks).After gavage,cecal feces and femoral heads were collected for fecal metabolomics analysis and bone tissue Micro-CT and hematoxylin-eosin staining,respectively.RESULTS AND CONCLUSION:(1)Metabolomics analysis results showed that there were 233 differential metabolites between the Cornus Cervi Col la and model groups,with 65 significantly differing and clearly annotated metabolites.Lipid and amino acid metabolites were significantly increased,with bile acids,sulfated steroids,ephedrine,hypoxanthine,betaine,L-carnitine,B-mouse bile acid,cytidine,4-pyridoxic acid,taurine,N-acetyl-d-glucosamine,and butyric acid being the most impacted(variable weight value VIP>5).The metabolic pathways of taurine and hypotaurine were crucial in the metabolic regulatory network(pathway impact=0.428 57).(2)Micro-CT scanning results of bone tissue showed that the femoral heads of rats in the model group and the Cornus Cervi Col la group had different degrees of damage;the femoral head contour was irregular;the trabeculae in the subchondral bone of the femoral head were missing and disordered,and some cystic structures were visible.Compared with the model group,the degree of trabecular damage in the rats of the Cornus Cervi Colla group was milder.Hematoxylin-eosin staining results showed that the trabeculae in the subchondral bone of the femoral heads of rats in the model group and the Cornus Cervi Colla group were sparse or interrupted,and the empty bone lacuna rate and adipocyte invasion were increased.Compared with the model group,the empty bone lacuna rate and adipocyte invasion in the subchondral bone of the femoral heads of rats in the Cornus Cervi Colla group were reduced.(3)These results conclude that Cornus Cervi Colla potentially mitigates steroid-induced osteonecrosis of the femoral head through the metabolic processes involving taurine and associated pathways.
10.Design and implementation of online continuing education platform for transfusion medicine
Haiying LI ; Xin LI ; Lixue CHEN ; Jinlian LUO ; Xiaodan PENG ; Jintong ZHONG ; Le BAI ; Nannan ZHANG ; Zebo YU ; Xue HU
Chinese Journal of Medical Education Research 2025;24(3):419-425
To provide in-service medical technicians and nurses with convenient access to continuing education resources in transfusion medicine, reduce transfusion-related adverse events, and ensure the safety, rationalization, and effectiveness of clinical transfusion, we designed and developed an online transfusion continuing education platform. The platform was based on the new managed code programming model.NET Core and the powerful functions of hypertext preprocessor PHP 7.4, addressing current issues in transfusion online continuing education. Through in-depth analysis of student attributes, learning behaviors, and teaching behaviors, a comprehensive online continuous teaching quality evaluation index system was established. This system not only facilitates the quantitative assessment of teaching quality but also successfully integrates the two core functions of teaching and management, thereby achieving unified online teaching.


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