Environmental pollution is a significant public health challenge worldwide, and investigating the causal relationship between environmental exposure and population health outcomes is a key objective of environmental epidemiology research. In recent years, the complexity of environmental exposures has increasingly come to the forefront, making it challenging for observational studies that dominate environmental epidemiology to accurately estimate causal effects. Causal inference methods are particularly advantageous in controlling for confounding factors, thus holding great potential in environmental epidemiology research. Researchers can use appropriate causal inference methods to simulate the process of randomization, providing strong support for revealing the causal relationship between environmental exposure and health outcomes. However, there is a lack of reviews on the application of causal inference methods in environmental epidemiology studies in China. Therefore, this study introduced the basic principles of common causal inference statistical methods in environmental epidemiology, summarized the applicable conditions, advantages and disadvantages of various methods, and provided R software implementation codes for these methods, aiming to offer guidance for optimizing research design and practicing causal inference statistical methods.

ObjectiveBased on the conjoint analysis of transcriptome and metabolome， the key genes in the phenylpropanoid biosynthesis pathway of Lonicera macranthoides were explored， which provided a basis for further exploring the synthesis and regulation mechanism of phenylpropanoid compounds in "Xianglei" L. macranthoides. MethodsThe stem， leaves， and three flowering flowers of "Xianglei" L. macranthoides were selected as experimental materials to construct transcriptome and metabolome. The transcriptome and metabolomics were conjointly analyzed by the Kyoto Encyclopedia of Genes and Genomes （KEGG） database and weighted correlation network analysis （WGCNA）， and the key genes in the phenylpropanoid biosynthesis pathway of L. macranthoides were explored. ResultsIn this study， 77 differential phenylpropanoids and 315 differential genes were found. Through the joint analysis of transcription and metabolism， nine key differential metabolites and four key genes related to them were finally discovered. Among them， cinnamic acid， 5-O-caffeoylshikimic acid，sinapyl alcohol， and chlorogenic acid were higher in flowers， and the content of the iconic effective component， namely chlorogenic acid，decreased sharply during the withering period. Caffeic acid，ferulic acid， 5-hydroxyconiferaldehyde，p-coumaryl alcohol， and syringin were higher in leaves. These four key genes belong to the cinnamic alcohol dehydrogenase （CAD） family， 4-coumaric acid： Coenzyme A （4CL） family， hydroxycinnamyl transferase （HCT） family， and L-phenylalanine ammonlyase （PAL） family genes. ConclusionAmong the four key genes excavated from L. macranthoides， TRINITY_DN42767_c0_g6 is related to the synthesis of p-coumaryl alcohol and sinapyl alcohol. TRINITY_DN43525_c4_g1 uses caffeic acid，ferulic acid，and cinnamic acid as substrates to catalyze the next reaction. TRINITY_DN47958_c3_g4 correlates with the synthesis of 3-p-coumaroyl quinic acid and caffeoyl-CoA， and TRINITY_DN52595_c1_g2 correlates with cinnamic acid synthesis. These findings provide a basis for further exploring the synthesis and regulation mechanism of phenylpropanoids in "Xianglei" L. macranthoides.

Liver fibrosis is a vital cause of morbidity in patients with liver diseases and developing novel anti-fibrotic drugs is imperative. Isovalerylspiramycin I (ISP I) as a major component of carrimycin applied to upper respiratory infections, was first found to possess anti-fibrotic potential. The present study aims to evaluate the functions and mechanisms of ISP I in protecting against liver fibrosis. According to our results, ISP I not only reduced the expressions of fibrogenic markers in LX-2 cells but also appeared great protective effects on liver injury and liver fibrosis in bile duct ligation (BDL) rats and carbon tetrachloride (CCl₄) mice. We proved that nucleotide-binding protein 2 (NUBP2) was the direct target of ISP I. ISP I through targeting NUBP2, increased the amount of vascular non-inflammatory molecule-1 (VNN1) on the cell membrane, which will inhibit oxidative stress and fibrosis. Simultaneously, the original carrimycin's protective effect on liver damage and fibrosis was verified. Therefore, our study provides potential agents for patients with liver fibrosis-related diseases, and the clear mechanism supports wide application in the clinic.

Objective To explore the role of X chromosome encoded epigenetic regulator UTX in NK cell-mediated anti-tumor activity.Methods Male Ncr1-iCre mice were crossed with female UTXfl/fl mice to generate F1 Ncr1-iCre+UTXfl/-male mice,which were further crossed with female UTXfl/fl mice to obtain male Ncr1-iCre-UTX fl/-control mice(M-Con)and NK-specific deletion of UTX male mice Ncr1-iCre+UTXfl/-(M-KO),as well as female Ncr1-iCre-UTXfl/fl control mice(F-Con)and UTX-deficient female mice Ncr1-iCre+UTXfl/fl(F-KO).UTX-deficient mice were injected with melanoma cell line B16F10 via tail vein to observe pulmonary metastatic tumor nodules.Moreover,flow cytometry was applied to detect the proportion and quantity of pulmonary NK cells(CD3-CD19-NK1.1+),maturation makers KLRG1 and CD11b,activation receptors NKG2D and CD69,and effector molecules,including perforin,granzyme B,CD107a,and IFN-γ.Then pulmonary NK cells were sorted and co-cultured with B16F10 cells,and the apoptosis of the melanoma cells was measured with flow cytometry.Results Compared with the M-Con mice,the M-KO mice presented less number of pulmonary tumor nodules(P<0.05),increased proportion and quantity of NK cells in the tumor microenvironment(P<0.01),though no obvious changes in the ratio of NK maturation makers KLRG1 to CD11b,enhanced expression level of cytotoxic molecule perforin(P<0.01),but no changes in the expression of effector molecule granzyme B,degranulation marker CD107a and cytokine IFN-γ in NK cells.Co-culture of NK cells and B16F10 cells promoted the apoptosis of tumor cells(P<0.05).Compared with the F-Con mice,the F-KO mice had no statistical difference in the number of pulmonary tumor nodules,but larger proportion and number of NK cells(P<0.05),decreased ratio of KLRG1 to CD11b(P<0.01),elevated level of perforin but decreased levels of granzyme B,CD107a and IFN-γ in NK cells(P<0.01).The co-culture of NK cells and B16F10 cells reduced the apoptosis of tumor cells in F-KO female mice(P<0.05).Conclusion NK-specific deletion of UTX regulates pulmonary metastasis of melanoma in a sex-dependent manner.

In recent years, the relationship between intestinal flora dysbiosis and abnormal bile acid metabolism and anxiety has received widespread attention. This article discussed the biological mechanism of the pathogenesis of anxiety from the perspective of intestinal flora and bile acid metabolism, in order to provide new ideas and theoretical basis for the TCM prevention and treatment of anxiety. According to TCM, spleen and stomach belong to earth, liver and gallbladder belong to wood, when spleen qi is healthy, the normal distribution of water and grain essence can be achieved, so that the liver can be nourished, qi and blood is sufficient, and its excretory function is normal, and the bile is sufficient. Once the spleen is not healthy, the distribution of water and grain essence is good, affecting the metabolism of fluids, resulting in phlegm and dampness, the qi is not smooth, can affect the liver's excretory function; liver and wood depression for a long time, transgressing the spleen and earth, qi and blood lack of biochemical sources, the formation of soil congestion and wood depression of the pathological phenomenon will appear. From the viewpoint of modern medicine and molecular biology, changes in the structure of intestinal flora affect the organism through neurological, endocrine, immune and metabolic pathways, which is consistent with the pathogenesis of "congestion of the earth"; disorders in the metabolism of bile acids can lead to changes in neurotransmitters and synaptic structure in the brain, causing anxiety symptoms, which is consistent with the characteristics of "wood depression". The bile acid metabolism disorder can cause neurotransmitter and synaptic structure changes in the brain, causing anxiety symptoms, which is consistent with the characteristics of "wood depression". It is important to regulate the intestinal flora and bile acid metabolism pathway to ease the liver and strengthen the spleen to improve anxiety.

Liver fibrosis is a vital cause of morbidity in patients with liver diseases and developing novel anti-fibrotic drugs is imperative.Isovalerylspiramycin Ⅰ(ISP Ⅰ)as a major component of carrimycin applied to upper respiratory infections,was first found to possess anti-fibrotic potential.The present study aims to evaluate the functions and mechanisms of ISP Ⅰ in protecting against liver fibrosis.According to our results,ISP Ⅰ not only reduced the expressions of fibrogenic markers in LX-2 cells but also appeared great protective effects on liver injury and liver fibrosis in bile duct ligation(BDL)rats and carbon tetrachloride(CCl4)mice.We proved that nucleotide-binding protein 2(NUBP2)was the direct target of ISP Ⅰ.ISP Ⅰ through targeting NUBP2,increased the amount of vascular non-inflammatory molecule-1(VNN1)on the cell membrane,which will inhibit oxidative stress and fibrosis.Simultaneously,the original carri-mycin's protective effect on liver damage and fibrosis was verified.Therefore,our study provides po-tential agents for patients with liver fibrosis-related diseases,and the clear mechanism supports wide application in the clinic.

Objective:To explore high-risk sexual behaviors of HIV/AIDS and related factors in young students in Guangzhou.Methods:A cross-sectional survey was conducted in 5 different types of Guangzhou colleges by convenience sampling with minimum number of classes per grade and 600 samples per school from September to November 2021. The R 4.2.2 software was used to consolidate databases. Simultaneously, a logistic regression model and a decision tree algorithm model, stratifying by whether sexual behaviors had occurred before, were constructed. In each layer, the prediction performance of the two models was evaluated through area under receiver operating characteristic and the confusion matrix, and then the model with high prediction performance was retained.Results:A total of 7 346 students were surveyed. The proportion of the respondents reporting sexual experience were 9.08% (667/7 346), in whom 26.24% (175/667) had risky sexual activity in the past year. The decision tree algorithm model performs well in predicting whether high-risk sexual behaviors have occurred in the past year. When the complexity parameter value is 0.018, and nsplit reaches 4, which means there are 5 leaf nodes in the model, the cross error of the tree will be the smallest. The first best grouping variable in the decision tree was whether to use condoms throughout the first sexual behavior. If condoms were used at their sexual debut, but homosexual practices have occurred in the past year, the probability of risky sexual behavior will increase. If homosexual practices have not occurred in the past year, but the age of sexual debut was below 18 years old while the period of HIV education was after high school, the probability of risk sexual behavior will also increase.Conclusions:AIDS-related risky behaviors of young students still deserved attention. The experience of sexual debut and whether AIDS-related health education has been received before the sexual debut were significant predictors for the occurrence of high-risk sexual behavior. The decision tree algorithm model has particular applicability for predicting and screening potential risk populations.

BACKGROUND:Due to the young age of children,the occipital condyle and foramen magnum are not fully developed,and they are prone to various diseases and injuries in the occipitocervical junction,which requires surgical treatment in severe cases.However,anatomical parameters for the development of the occipital condyle and foramen magnum in children are lacking. OBJECTIVE:To measure the morphological structure of the occipital condyle and foramen magnum by three-dimensional reconstruction technique,and to provide important anatomical parameters for occipitocervical junction lesions,related surgical procedures and forensic identification. METHODS:Imaging data of 389 cases of primitive children and adolescents involved in skull base undergoing spiral CT scanning(247 males and 142 females)aged 1-18 years were collected and divided into 1-3-year-old group,4-6-year-old group,7-9-year-old group,10-12-year-old group,13-15-year-old group,and 16-18-year-old group according to their age.Mimics 16.0 software was used to reconstruct the skull base and measure the length and width of the foramen magnum.A formula was used to calculate the area and index of the foramen magnum.We measured the length,width and height of the occipital condyle,the angle between the long axis and the sagittal axis of the occipital condyle(O-S angle),the included angle between the midpoint of the front and back edges of the foramen magnum and the connection between the back edge of occipital condyle and the intersection point of the foramen magnum(F-O angle),and the included angle between the midpoint of the front and back edges of the foramen magnum and the midpoint of the back wall of the sublingual neural tube(F-H angle).Gender,side and age differences were analyzed among the indicators. RESULTS AND CONCLUSION:(1)In foramen magnum measurement,there was no significant difference between sexes in the index of the foramen magnum(P>0.05),but there were significant differences in length,width and area of the foramen magnum(P<0.05).(2)The O-S angle,F-O angle and F-H angle of the occipitral condyle were not significantly different between genders(P>0.05),but length,width and height of the occipital condyle were significantly different between genders(P<0.05).(3)There were no significant differences in the length of the occipital condyle among different groups(P>0.05),but there were significant differences in the width and height of the occipital condyle,O-S angle,F-O angle and F-H angle among different groups(P<0.05).(4)Length,width and area of the foramen magnum,length,width and height of the occipital condyle showed a wavy increasing trend with the increase of age,while O-S,F-O and F-H angles showed a wavy decreasing trend with the increase of age,while the index of the foramen magnum showed no significant change.(5)In conclusion,there are gender and lateral differences in the morphological indexes of the foramen magnum and the occipital condyle in children.These differences can provide an important reference for clinical surgical approach selection and forensic examination.

Objective To investigate the changes in blood microbiota in patients with high altitude polycythemia(HAPC)and the correlation with the risk of HAPC.Methods A cross-sectional trial was carried out among 41 HAPC patients(HAPC group)and 41 healthy plateau individuals(control group)who took physical examination in the Health Management Department of No.953 Hospital of PLA Army in 2021.High-throughput sequencing technology was used to detect the V3-V4 variable region of the 16S ribosomal RNA(16S rRNA)gene in the blood smaples,and the composition and difference of the blood microbiota were compared and analyzed between the 2 groups.Results All the participants were male and Han people,and there were no significant differences in baseline data such as age,body mass index and plateau migration time between the 2 groups(P＞0.05).The α-diversity of blood microbiota in the HAPC group,including the Simpson index(0.931±0.005 vs 0.907±0.008,P＜0.05),Goods Coverage index(0.998±0.001 vs 0.997±0.001,P＜0.001)and Pielou index(0.597±0.011 vs 0.567±0.009,P＜0.05)were significantly higher than those in the control group.Meanwhile,obvious difference was observed in the β diversity between the 2 groups(P＜0.01).The relative abundance analysis of bacteria showed that Pelomonas(0.046±0.004 vs 0.033±0.003,P＜0.05),Azospirillum(0.046±0.006 vs 0.021±0.003,P＜0.01),Acidovorax(0.032± 0.003 vs 0.019±0.002,Azospirillum(0.046±0.006 vs 0.021±0.003,P＜0.01)and Acidovorax(0.032± 0.003 vs 0.019±0.002,P＜0.05)were statistically higher in the HAPC group than the control group.LEfSe analysis showed that the characteristic blood microbiota of the HAPC group were α-Proteobacteria,and those of control group were Trichospiridae.Conclusion Significant changes are found in diversity,relative abundance and characteristic bacteria of the blood microbiota between the HAPC patients and healthy people at the high altitude,which might be closely associated with the occurrence and development of HAPC.

Objective:To explore the relationship between relapse tendency and childhood maltreatment in methamphetamine-dependent youths,and the role of impulsivity and quality of life in the relationship.Methods:To-tally 287 methamphetamine-dependent youths(160 females,127 males)were selected in compulsory drug rehabili-tation centers.The Relapse Tendency Questionnaire(RTQ),Childhood Trauma Questionnaire-Short Form(CTQ-SF),Barrett Impulsivity Scale(BIS-11)and Quality of Life for Drug Addicts(QOL-DA)for Drug Addicts were used to conduct the survey.SPSS macro program PROCESS was used to test the mediating role.Results:The BIS-11 total scores acted as a partial mediator between the total scores of CTQ-SF and RTQ,with an effect value of 0.03(95％CI:0.01-0.05),the QOL-DA total scores acted as a full mediator between the total scores of CTQ-SF and RTQ,with an effect value of 0.05(95％CI:0.02-0.08),and the scores of BIS-11 and QOL-DA acted as chain mediators between total scores of CTQ-SF and RTQ,with an effect value of 0.01(95％CI:0.00-0.03).Conclusion:Childhood maltreatment,impulsivity,and quality of life may be associated with relapse tendencies in methamphetamine-dependent youths.