1.Exploring Chemical Constituent Distribution in Blood/Brain(Hippocampus) and Emotional Regulatory Effect of Raw and Vinegar-processed Products of Citri Reticulatae Pericarpium Viride
Yi BAO ; Yonggui SONG ; Qianmin LI ; Zhifu AI ; Genhua ZHU ; Ming YANG ; Huanhua XU ; Qin ZHENG ; Yiting HUANG ; Zihan GAO ; Dan SU
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(2):189-197
ObjectiveTo investigate the migration and distribution characteristics of chemical constituents in blood and hippocampal tissues before and after vinegar processing of Citri Reticulatae Pericarpium Viride(CRPV), and to explore the potential material basis and mechanisms underlying their regulatory effects on emotional disorders by comparing the effects of raw and vinegar-processed products of CRPV. MethodsUltra-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry(UPLC-Q-TOF-MS/MS) was employed to characterize and identify the chemical constituents of raw and vinegar-processed products of CRPV extracts, as well as their migrating components in blood and hippocampal tissues after oral administration. Reference standards, databases, and relevant literature were utilized for compound annotation, with data processing performed using PeakView 1.2 software. Seventy male C57BL/6 mice were randomly divided into seven groups, including the blank group, model group, diazepam group(2.5 mg·kg-1), raw CRPV low/high dose groups(0.6, 1.2 g·kg-1), and vinegar-processed CRPV low/high dose groups(0.6, 1.2 g·kg-1), with 10 mice per group. Except for the blank group, all other groups underwent chronic restraint stress(2 h·d-1) for 20 d. Each drug-treated group received oral administration at the predetermined dose starting 10 d after modeling, with a total treatment duration of 10 d. Following model-based drug administration, mice underwent open-field, forced swimming, and elevated plus maze tests. After anesthesia with isoflurane, whole brains were collected from each group of mice, and hippocampi were dissected. Reactive oxygen species(ROS) level in hippocampal tissues was quantified by enzyme-linked immunosorbent assay(ELISA). Hematoxylin-eosin(HE) staining was used to observe hippocampal tissue morphology. Immunofluorescence was performed to detect neuronal nuclei(NeuN) and peroxisome proliferator-activated receptor alpha(PPARα) expressions in hippocampal tissue. Then, pharmacodynamic evaluations were conducted to assess the effects of raw and vinegar-processed CRPV on mood disorders, exploring the potential mechanisms. ResultsVinegar processing caused significant changes in the chemical composition of CRPV, with 18 components showing increased relative content and 35 components showing decreased relative content. The primary changes occurred in flavonoid compounds, including 20 flavonoids, 20 flavonoid glycosides, 3 triterpenes, 3 phenolic acids, 1 alkaloid, and 6 other compounds. Twenty-one components were detected in blood(15 methoxyflavones, 4 flavonoid glycosides, and 2 phenolic acids), with 17 shared between raw and vinegar-processed CRPV. Seven components reached hippocampal tissues(all common to both forms). In regulating emotional disorders, Vinegar-processed CRPV exhibited superior antidepressant-like effects compared to raw products. HE staining revealed that both treatments improved hippocampal neuronal morphology, particularly in the damaged CA1 and CA3 regions. Immunofluorescence and ELISA analyses demonstrated that both raw and vinegar-processed CRPV significantly modulated NeuN and PPARα expressions in hippocampal tissue while alleviating oxidative stress induced by excessive ROS(P<0.05). ConclusionThe chemical composition of CRPV undergoes changes after vinegar processing, but the migrating components in blood and hippocampus are primarily methoxyflavonoids. These components may serve as the potential material basis for activating the PPARα pathway, thereby negatively regulating ROS generation in the hippocampus, reducing oxidative stress, and promoting the development of NeuN-positive neurons. These findings provide experimental evidence for enhancing quality standards, pharmacodynamic material research, and active drug development of raw and vinegar-processed CRPV.
2.Effect of Wulao Qisun Prescription on Proliferation and Osteogenic Differentiation of AS Fibroblasts by Regulating Wnt/β-catenin Signaling Pathway
Juanjuan YANG ; Ping CHEN ; Haidong WANG ; Zhendong WANG ; Haolin LI ; Zhimin ZHANG ; Yuping YANG ; Weigang CHENG ; Jin SU ; Jingjing SONG ; Dongsheng LU
Chinese Journal of Experimental Traditional Medical Formulae 2025;31(2):67-73
ObjectiveTo investigate the effect and underlying mechanism of the Wulao Qisun prescription on pathological new bone formation in ankylosing spondylitis (AS). MethodsSynovial fibroblasts were isolated from the hip joints of AS patients and observed under a microscope to assess cell morphology. The cells were identified using immunofluorescence staining. The isolated AS fibroblasts were divided into blank group, low drug-containing serum group, medium drug-containing serum group, high drug-containing serum group, and positive drug group. After drug intervention, cell proliferation was measured using the cell counting kit-8 (CCK-8) assay to observe fibroblast growth and determine the optimal intervention time. Alkaline phosphatase (ALP) activity was measured using the alkaline phosphatase assay. Protein expression of osteocalcin (OCN), osteopontin (OPN), and runt-related transcription factor 2 (Runx2) was detected by Western blot. The mRNA expression levels of Wnt5a, β-catenin, and Dickkopf-1 (DKK-1) were measured by real-time quantitative polymerase chain reaction (Real-time PCR). ResultsCompared with the blank group, each drug-containing serum group of Wulao Qisun prescription and the positive drug group inhibited the proliferation of AS fibroblasts and reduced ALP expression (P<0.01). Compared with the blank group, the low drug-containing serum group of Wulao Qisun prescription downregulated β-catenin mRNA expression (P<0.05). The medium and high drug-containing serum groups and the positive drug group significantly downregulated Wnt5a and β-catenin mRNA expression (P<0.05, P<0.01), with the positive drug group showing the most pronounced effect (P<0.01). The high drug-containing serum group and the positive drug group significantly upregulated DKK-1 mRNA expression (P<0.01). Compared with the blank group, the low drug-containing serum group of Wulao Qisun prescription inhibited the expression of OPN and Runx2 proteins (P<0.05, P<0.01), while the medium and high drug-containing serum groups and the positive drug group inhibited the expression of OCN, OPN, and Runx2 proteins (P<0.05, P<0.01). ConclusionThe Wulao Qisun prescription can inhibit the proliferation and osteogenic differentiation of AS fibroblasts, thereby delaying the formation of pathological new bone in AS. The possible mechanism involves the regulation of Wnt/β-catenin-related gene expression, further inhibiting the transcription of downstream target genes.
3.A prediction model for high-risk cardiovascular disease among residents aged 35 to 75 years
ZHOU Guoying ; XING Lili ; SU Ying ; LIU Hongjie ; LIU He ; WANG Di ; XUE Jinfeng ; DAI Wei ; WANG Jing ; YANG Xinghua
Journal of Preventive Medicine 2025;37(1):12-16
Objective:
To establish a prediction model for high-risk cardiovascular disease (CVD) among residents aged 35 to 75 years, so as to provide the basis for improving CVD prevention and control measures.
Methods:
Permanent residents aged 35 to 75 years were selected from Dongcheng District, Beijing Municipality using the stratified random sampling method from 2018 to 2023. Demographic information, lifestyle, waist circumference and blood biochemical indicators were collected through questionnaire surveys, physical examinations and laboratory tests. Influencing factors for high-risk CVD among residents aged 35 to 75 years were identified using a multivariable logistic regression model, and a prediction model for high-risk CVD was established. The predictive effect was evaluated using the receiver operating characteristic (ROC) curve.
Results:
A total of 6 968 individuals were surveyed, including 2 821 males (40.49%) and 4 147 females (59.51%), and had a mean age of (59.92±9.33) years. There were 1 155 high-risk CVD population, with a detection rate of 16.58%. Multivariable logistic regression analysis showed that gender, age, smoking, central obesity, systolic blood pressure, fasting blood glucose, triglyceride and low-density lipoprotein cholesterol were influencing factors for high-risk CVD among residents aged 35 to 75 years (all P<0.05). The area under the ROC curve of the established prediction model was 0.849 (95%CI: 0.834-0.863), with a sensitivity of 0.693 and a specificity of 0.863, indicating good discrimination.
Conclusion
The model constructed by eight factors including demographic characteristics, lifestyle and blood biochemical indicators has good predictive value for high-risk CVD among residents aged 35 to 75 years.
4.Health risk assessment of fluoride and trichloromethane in drinking water in rural schools in Guizhou Province
JIAN Zihai, ZHANG Jianhua, SU Minmin, CHEN Xuanhao, YUAN Minlan, YANG Dan, CHEN Gang
Chinese Journal of School Health 2025;46(1):134-137
Objective:
To analyze the distribution characteristics of fluoride and trichloromethane in drinking water in rural schools in Guizhou Province and assess their health risks, so as to provide a scientific basis for ensuring the safety of drinking water in rural schools.
Methods:
During the dry season (March to May) and wet season (July to September) of 2020 to 2022, 788 rural primary and secondary schools in agricultural counties (districts) in Guizhou Province were selected for investigation by using a direct sampling method. A total of 1 566 drinking water samples were collected from these schools, and the mass concentrations of fluoride and trichloromethane in the water samples were detected. The Mann-Whitney U test was used for intergroup comparison, and a health risk assessment model was employed to evaluate the health risks of students oral intake of fluoride and trichloromethane.
Results:
From 2020 to 2022, the mass concentrations of fluoride and trichloromethane in the drinking water of rural schools in Guizhou Province all met the standards, and the ranges were no detection to 0.99 mg/L and (no detection to 0.06)×10 -3 mg/L, respectively. The mass concentrations of fluoride in dry and wet seasons were 0.05(0.05,0.10), 0.05(0.05,0.10) mg/L, the mass concentrations of trichloromethane were [0.02(0.02,1.00)]×10 -3 , [0.02(0.02,1.00)]×10 -3 mg/L, the mass concentrations of fluoride in factory water and terminal water were 0.05(0.05,0.05), 0.05(0.05,0.10) mg/L, and the differences were not statistically significant ( Z=-0.04, -0.88, - 0.98 , P >0.05). There was a statistically significant difference in the mass concentration of trichloromethane between factory water and peripheral water [0.02(0.02,0.02)×10 -3 , 0.02(0.02,1.05)×10 -3 mg/L]( Z=-2.16, P < 0.05 ). The non-carcinogenic risk assessment values for students oral exposure to fluoride and trichloromethane were in the range of 0.01(0.01,0.03)-0.03(0.03,0.06) and [0.26( 0.26 ,14.54)]×10 -4 -[0.52(0.52,48.62)]×10 -4 , respectively, all of which were at acceptable levels; the carcinogenic risk assessment values for oral exposure to trichloromethane were in the range of [0.08(0.08, 4.51 )]×10 -7 -[0.16(0.16,15.07)]×10 -7 , indicating a low risk.
Conclusions
The health risks of students expore to fluoride and trichloromethane in drinking water in rural schools of Guizhou Province are low. It is necessary to strengthen the standardized management of disinfection in some rural drinking water projects and the monitoring of fluoride in water sources to reduce the exposure risk to children.
5.Study on the influential factors of blood concentration for duloxetine based on therapeutic drug monitoring
Yang LUN ; Liguang DUAN ; Feiyue AN ; Ran FU ; Jing YU ; Chaoli CHEN ; Mengqiang ZHAO ; Shi SU ; Yang SONG ; Jiaqi WANG ; Yuhang YAN ; Chunhua ZHOU
China Pharmacy 2025;36(6):727-731
OBJECTIVE To explore the main factors influencing the blood concentration of duloxetine, and provide a scientific basis for the individualized use of duloxetine. METHODS Retrospective analysis was conducted on 434 inpatients with depressive disorders at the First Hospital of Hebei Medical University, who were treated with duloxetine and underwent blood concentration monitoring between January 2022 and April 2024. The study examined the impact of various factors, including gender, age, body mass index (BMI), gene phenotypes, combined medication, drug type (original/generic), and genotyping results of gene single nucleotide polymorphism loci, on blood concentration and the concentration-to-dose (C/D) after dose adjustment. RESULTS The blood concentration of duloxetine was 76.65 (45.57, 130.31) ng/mL, and C/D was 0.96 (0.63, 1.60) ng·d/(mL·mg). The blood concentration of duloxetine was positively correlated with the daily dose of administration (R2=0.253 7, P<0.001). Blood concentration of duloxetine in 38.94% of patients exceeded the recommended range specified in the guidelines. Gender, age, BMI, combined use of CYP2D6 enzyme inhibitors, and CYP2D6 and CYP1A2 phenotypes had significant effects on C/D of duloxetine (P<0.05). CONCLUSIONS The patient’s age, gender, BMI, combined medication, and genetic phenotypes are closely related to the blood concentration of duloxetine.
6.Nutrition literacy of primary and secondary school students and its influencing factors in Shijingshan District of Beijing
Deyue XU ; Mingliang WANG ; Wei WANG ; Yingjie YU ; Shuiying YUN ; Bo YANG ; Yunzheng YAN ; Lingyan SU
Journal of Public Health and Preventive Medicine 2025;36(2):126-130
Objective To understand the current situation of nutrition literacy of primary and secondary school students in Shijingshan District of Beijing, and analyze its influencing factors, and to put forward targeted suggestions for improving the students’ nutrition literacy and promoting their healthy growth. Methods A multi-stage stratified cluster sampling method was used to select 2480 primary and secondary school students and their parents from 5 primary schools, 3 middle schools and 1 high school in Shijingshan District. The multivariate logistic regression model was used to analyze the factors influencing the attainment rate of nutrition literacy. Results The median score of nutrition literacy of 2480 primary and secondary school students from grades 1 to 12 was 77.86 (in hundred-mark system), the quartile range (IQR) was 16.96, and the attainment rate of nutrition literacy was 42.46%. The cognitive level (45.12%) was higher than the skill level (41.20%) among students from grades 3 to 12. In terms of skills, the attainment rate of food preparation was the lowest, at 30.38%. The scores of nutrition literacy of girls were higher than those of boys, and the scores of primary school students were higher than those of secondary school students. Students with different levels of caregiver’s education, family income, and family food environment had different scores of nutrition literacy, and the differences were statistically significant (P<0.05). Multivariate logistic regression analysis showed that the attainment rate of nutrition literacy was closely related to student’s gender and study stage, caregiver’s education level, and family food environment. Conclusion The nutrition literacy of primary and secondary school students in Shijingshan District still needs to be improved, especially in the aspect of skills. Targeted nutrition education should be carried out.
7.Structural and Spatial Analysis of The Recognition Relationship Between Influenza A Virus Neuraminidase Antigenic Epitopes and Antibodies
Zheng ZHU ; Zheng-Shan CHEN ; Guan-Ying ZHANG ; Ting FANG ; Pu FAN ; Lei BI ; Yue CUI ; Ze-Ya LI ; Chun-Yi SU ; Xiang-Yang CHI ; Chang-Ming YU
Progress in Biochemistry and Biophysics 2025;52(4):957-969
ObjectiveThis study leverages structural data from antigen-antibody complexes of the influenza A virus neuraminidase (NA) protein to investigate the spatial recognition relationship between the antigenic epitopes and antibody paratopes. MethodsStructural data on NA protein antigen-antibody complexes were comprehensively collected from the SAbDab database, and processed to obtain the amino acid sequences and spatial distribution information on antigenic epitopes and corresponding antibody paratopes. Statistical analysis was conducted on the antibody sequences, frequency of use of genes, amino acid preferences, and the lengths of complementarity determining regions (CDR). Epitope hotspots for antibody binding were analyzed, and the spatial structural similarity of antibody paratopes was calculated and subjected to clustering, which allowed for a comprehensively exploration of the spatial recognition relationship between antigenic epitopes and antibodies. The specificity of antibodies targeting different antigenic epitope clusters was further validated through bio-layer interferometry (BLI) experiments. ResultsThe collected data revealed that the antigen-antibody complex structure data of influenza A virus NA protein in SAbDab database were mainly from H3N2, H7N9 and H1N1 subtypes. The hotspot regions of antigen epitopes were primarily located around the catalytic active site. The antibodies used for structural analysis were primarily derived from human and murine sources. Among murine antibodies, the most frequently used V-J gene combination was IGHV1-12*01/IGHJ2*01, while for human antibodies, the most common combination was IGHV1-69*01/IGHJ6*01. There were significant differences in the lengths and usage preferences of heavy chain CDR amino acids between antibodies that bind within the catalytic active site and those that bind to regions outside the catalytic active site. The results revealed that structurally similar antibodies could recognize the same epitopes, indicating a specific spatial recognition between antibody and antigen epitopes. Structural overlap in the binding regions was observed for antibodies with similar paratope structures, and the competitive binding of these antibodies to the epitope was confirmed through BLI experiments. ConclusionThe antigen epitopes of NA protein mainly ditributed around the catalytic active site and its surrounding loops. Spatial complementarity and electrostatic interactions play crucial roles in the recognition and binding of antibodies to antigenic epitopes in the catalytic region. There existed a spatial recognition relationship between antigens and antibodies that was independent of the uniqueness of antibody sequences, which means that antibodies with different sequences could potentially form similar local spatial structures and recognize the same epitopes.
8.Effect of Different Fermentation Conditions on Fungal Community and Chemical Composition of Aurantii Fructus
Zhihong YAN ; Xiumei LIU ; Qiuyan GUAN ; Yonggui SONG ; Zhifu AI ; Genhua ZHU ; Yuhui PING ; Ming YANG ; Qin ZHENG ; Huanhua XU ; Dan SU
Chinese Journal of Experimental Traditional Medical Formulae 2025;31(11):254-262
ObjectiveTo investigate the effects of different fermentation methods and times on the fungal flora and chemical composition of Aurantii Fructus, in order to obtain the optimal fermentation conditions and flora structure, and to ensure the stability and controllability of the fermented varieties. MethodsScanning electron microscopy was used to observe and analyze the colony characteristics on the surface of Aurantii Fructus under different fermentation conditions. Internal transcribed spacer 2(ITS2) high-throughput sequencing, combined with fungal community diversity analysis and fungal community structure analysis, were used to obtain the fungal flora microbial categories of Aurantii Fructus under the conditions of traditional pressure-shelf fermentation and non-pressure-shelf natural fermentation for 7, 14, 21 d(numbered Y1-Y3 for the former, and numbered F1-F3 for the latter), respectively. At the same time, the chemical components in the fermentation process were detected by ultra-high performance liquid chromatography-quadrupole-time-of-flight mass spectrometry(UPLC-Q-TOF-MS/MS), combined with principal component analysis(PCA), partial least squares-discriminant analysis(PLS-DA) and compound retention time, parent ions, characteristic fragment ions and other information, the differential compounds between the different fermentation samples were screened and identified. ResultsThe analysis of fungal community diversity showed that the dominant flora did not change at different fermentation time points in the traditional pressure-shelf fermentation method, while in the non-pressure-shelf natural fermentation method, there was a significant difference with the fermentation process, and at the genus level, the dominant genus of samples Y1, Y2, Y3 and F2 was Aspergillus, while the dominant genera of samples F1 and F3 were both Rhizopus. This indicated that the microbial growth environment provided by the traditional fermentation method was more stable, and the microbial community structure was more stable, which was more conducive to the stable and controllable fermentation process and fermented products. A total of 155 compounds were identified by compositional analysis, including 70 flavonoids, 38 coumarins, 10 alkaloids, 34 organic acids and 3 other compounds. After fermentation, two new components of ribalinine and pranferin were produced. Different fermentation conditions also brought about differences in chemical composition, multivariate statistical analysis obtained 26 differential compounds under two different fermentation methods, mainly including flavonoids, organic acids and coumarins. Comprehensively, the microbial community structure of samples fermented by the traditional pressure-shelf method of Aurantii Fructus for 14 d was stable, the species richness was high and the overall content of differential compounds was high, which was the optimal processing condition. ConclusionCompared with non-pressure-shelf natural fermentation, the traditional method has obvious advantages in terms of the stability of the microbial community structure and the content of chemical compounds, and the optimal condition is 14 days of fermentation. This study is helpful to promote the quality stability and fermentation bioavailability of fermented products of Aurantii Fructus, as well as to provide an experimental basis for the further improvement of the quality control methods of this variety.
9.Effect of Different Fermentation Conditions on Fungal Community and Chemical Composition of Aurantii Fructus
Zhihong YAN ; Xiumei LIU ; Qiuyan GUAN ; Yonggui SONG ; Zhifu AI ; Genhua ZHU ; Yuhui PING ; Ming YANG ; Qin ZHENG ; Huanhua XU ; Dan SU
Chinese Journal of Experimental Traditional Medical Formulae 2025;31(11):254-262
ObjectiveTo investigate the effects of different fermentation methods and times on the fungal flora and chemical composition of Aurantii Fructus, in order to obtain the optimal fermentation conditions and flora structure, and to ensure the stability and controllability of the fermented varieties. MethodsScanning electron microscopy was used to observe and analyze the colony characteristics on the surface of Aurantii Fructus under different fermentation conditions. Internal transcribed spacer 2(ITS2) high-throughput sequencing, combined with fungal community diversity analysis and fungal community structure analysis, were used to obtain the fungal flora microbial categories of Aurantii Fructus under the conditions of traditional pressure-shelf fermentation and non-pressure-shelf natural fermentation for 7, 14, 21 d(numbered Y1-Y3 for the former, and numbered F1-F3 for the latter), respectively. At the same time, the chemical components in the fermentation process were detected by ultra-high performance liquid chromatography-quadrupole-time-of-flight mass spectrometry(UPLC-Q-TOF-MS/MS), combined with principal component analysis(PCA), partial least squares-discriminant analysis(PLS-DA) and compound retention time, parent ions, characteristic fragment ions and other information, the differential compounds between the different fermentation samples were screened and identified. ResultsThe analysis of fungal community diversity showed that the dominant flora did not change at different fermentation time points in the traditional pressure-shelf fermentation method, while in the non-pressure-shelf natural fermentation method, there was a significant difference with the fermentation process, and at the genus level, the dominant genus of samples Y1, Y2, Y3 and F2 was Aspergillus, while the dominant genera of samples F1 and F3 were both Rhizopus. This indicated that the microbial growth environment provided by the traditional fermentation method was more stable, and the microbial community structure was more stable, which was more conducive to the stable and controllable fermentation process and fermented products. A total of 155 compounds were identified by compositional analysis, including 70 flavonoids, 38 coumarins, 10 alkaloids, 34 organic acids and 3 other compounds. After fermentation, two new components of ribalinine and pranferin were produced. Different fermentation conditions also brought about differences in chemical composition, multivariate statistical analysis obtained 26 differential compounds under two different fermentation methods, mainly including flavonoids, organic acids and coumarins. Comprehensively, the microbial community structure of samples fermented by the traditional pressure-shelf method of Aurantii Fructus for 14 d was stable, the species richness was high and the overall content of differential compounds was high, which was the optimal processing condition. ConclusionCompared with non-pressure-shelf natural fermentation, the traditional method has obvious advantages in terms of the stability of the microbial community structure and the content of chemical compounds, and the optimal condition is 14 days of fermentation. This study is helpful to promote the quality stability and fermentation bioavailability of fermented products of Aurantii Fructus, as well as to provide an experimental basis for the further improvement of the quality control methods of this variety.
10.Analyzing the occupational health literacy level and its influencing factors among workers in non-metallic mineral product industry in Yunfu City
Xiaoyue CHEN ; Xiaotang SU ; Jiabin CHEN ; Min YANG ; Huiqing CHEN ; Xiaoyi LI ; Jichao CHEN
China Occupational Medicine 2025;52(1):94-98
Objective To analyze the occupational health literacy (OHL) level and its influencing factors of workers in non-metallic mineral product industry in Yunfu City. Methods A total of 947 frontline workers from 24 non-metallic mineral products enterprises in Yunfu City were selected as the research subjects using the stratified random sampling method. The OHL level of the workers were assessed using the Occupational Health Literacy Questionnaire of National Key Populations. Results The overall OHL level of the research subjects was 58.3% (552/947). The OHL levels across four dimensions, from highest to lowest, were basic knowledge of occupational health protection (94.7%), healthy work practices and behaviors (81.8%), legal knowledge of occupational health (65.5%), and basic skills of occupational health protection (25.9%). The results of binary logistic regression analysis showed that workers with 2.0-<10.0 years and ≥10 years of work experience had higher OHL levels than those with <2.0 years of work experience (all P<0.01). Workers with a high school education or above had higher OHL levels than those with a junior high school education or below (all P<0.01). Workers in large- and medium-sized enterprises had higher OHL levels than those in small and micro-sized enterprises (both P<0.01). Conclusion The OHL levels of workers in Yunfu City's non-metallic mineral products industry can be further improved, particularly the occupational health protection skills and related legal knowledge. Workers with short seniority, low educational level, and in small and micro enterprises should be the key groups for improving OHL levels.


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