Background Metals and metalloids in fine particulate matter (PM_2.5) may cause damage to the respiratory and circulatory systems of the human body, and long-term exposure is prone to causing chronic poisoning, cancer, and other adverse effects. Objective To assess the distribution characteristics of metals and metalloids in outdoor PM_2.5 in a southern city of China, conduct source apportionment, and evaluate the associated health risks, thereby providing theoretical support for further pollution control measures. Methods PM_2.5 samples were collected in districts A, B, and C of a southern China city, and the concentrations of 17 metals and metalloids were detected by inductively coupled plasma-mass spectrometry (ICP-MS). Pollution sources were assessed through enrichment factor and principal components analysis, and the main pollution sources were quantified using absolute principal component scores-multivariate linear regression (APCS-MLR). Health risks were evaluated based on the Technical guide for environmental health risk assessment of chemical exposure (WS/T777—2021). Results The ambient air PM_2.5 concentrations in the city were higher in winter and spring, and lower in summer and autumn. The annual average concentrations of ambient PM_2.5 in districts A, B, and C were 36.7, 31.9, and 24.4 μg·m⁻³, respectively. The ambient PM_2.5 levels in districts B and C were below the second-grade limit set by the Ambient air quality standards (GB 3095—2012). The enrichment factors of cadmium (Cd), aluminum (Al), and antimony (Sb) were greater than 10, those of copper (Cu), lead (Pb), arsenic (As), nickel (Ni), mercury (Hg), and molybdenum (Mo) fell between 1 and 10, and those of manganese (Mn), vanadium (V), chromium (Cr), cobalt (Co), barium (Ba), beryllium (Be), and uranium (U) were below or equal to 1. The comprehensive evaluation of source analysis showed that the main pollution sources in districts A and C and the whole city were coal-burning. In district B, the main pollution source was also coal combustion, followed by industrial process sources and dust sources. The carcinogenic risks of As and Cr were between 1×10⁻⁶ and 1×10⁻⁴. However, the hazard quotients for 15 metals and metalloids in terms of non-carcinogenic risk were below 1. Conclusion Cr and As in the atmospheric PM_2.5 of the city present a certain risk of cancer and should be paid attention to. In addition, preventive control measures should be taken against relevant pollution sources such as industrial emission, dust, and coal burning.

ObjectiveTo understand the characteristics of PM_2.5 pollution in the air of Pearl River Delta city in Guangdong Province under the COVID-19 epidemic and the health risks of inhaling elements in PM_2.5. MethodsIn 2022， 10 PM_2.5 monitoring points were set up in 10 districts in Guangzhou， Shenzhen， Foshan and Zhuhai， and air samples were collected for 7 consecutive days every month to analyze the concentration of PM_2.5 and the 12 elements in PM_2.5. The classic "four-step" method was used to evaluate the carcinogenic risk and chronic non-carcinogenic risk of the elements in air PM_2.5 on health. The age-sensitive characteristics of metal elements were combined in the carcinogenic risk assessment， and age-sensitive factors were introduced to analyze the impact of air pollution on population health. ResultsA total of818 samples were collected. and the average annual PM_2.5 concentration in the four cities of the Pearl River Delta was 30.17 （1.00-166.00， s=21.06） μg·m^-3， which was lower than the concentration limit of the secondary standard of the Ambient Air Quality Standard （GB 3095-2012）. The difference of PM_2.5 concentration in the four cities was statistically significant. The PM_2.5 concentrations in Zhuhai and Shenzhen， which were located near the sea， were lower than those in Guangzhou and Foshan. The monthly mean concentration of PM_2.5 in the four cities was the lowest at 13.70 （4.00-34.00， s=5.93） μg·m^-3 in July and the highest at 57.73 （14.00-146.00， s=27.96） μg·m^-3 in January， showing a low concentration from May to October and a high concentration from November to April of the following year. The average daily PM_2.5 concentration exceeded the secondary standard for 29 days， mainly distributed in January and November. The average annual mass concentration of elements in PM_2.5 in the four cities was Al>Mn>Pb>As>Ni>Cr>Se>Sb>Cd>Tl>Be>Hg. AS and Mn have chronic non-carcinogenic risk in population， while Cr， AS， Cd， Be and Ni have carcinogenic risk in population. ConclusionThe PM_2.5 pollution levels of the four cities in the Pearl River Delta are low and variable. Coastal cities are lower than non-coastal cities， which shows the characteristics of first decreasing and then increasing throughout the year. The order of mass concentration of metal elements of PM_2.5 in four cities is basically the same except Be and Ni. As and Mn in PM_2.5 show a certain degree of chronic non-carcinogenic risk， and As， Cr， Cd， Ni and Be have a certain degree of carcinogenic risk. The four cities need to take effective intervention measures to continue to strengthen the pollution control and health protection of Cr， As， Cd and Mn in the air， and control the health burden caused by air pollution.

Objective: To investigate the associated factors of myopia among primary and secondary school students in Shenzhen, and to provide reference for the prevention and control of myopia. Methods: By stratified cluster sampling, 3 073 students of 14 schools including primary,junior,regular and vocational senior schools from two districts in Shenzhen were selected and investigated. Results: For primary school students, the time of using computer for 2-<3 hours per day (OR=2.23，95%CI=1.19-4.20) , and no physical education class(2 sections per week OR=0.34, 95%CI=0.13-0.91; 4 sections per week OR=0.23, 95%CI=0.08-0.62; 5 sections or more per week OR=0.33, 95%CI=0.11-0.97) were positively associated with myopia. Teachers finishing class on time at break (occasionally delaying OR=1.99, 95%CI=1.51-2.63; frequently delaying OR=2.07, 95%CI=1.29-3.30), taking 0.5-1 hour break when using eyes at close range (1-<2 hours OR=1.33，95%CI=1.03-1.70; ≥3 hours OR=1.87, 95%CI=1.17-3.00), no parents with myopia(one parent with myopia OR=1.69, 95%CI=1.32-2.17; two parents with myopia OR=2.13, 95%CI=1.50-3.02) were negatively associated with myopia. For junior high school students, without parents with myopia (one parent with myopia OR=3.27, 95%CI=2.17-4.94; two parents with myopia OR=5.38, 95%CI=2.78-10.42) was the protective factor of myopia. For senior high school students, male (female OR=1.52, 95%CI=1.07-2.14), doing eye exercises twice a day in school (OR=0.41, 95%CI=0.23-0.75), and accumulating outdoor activities for ≥2 hours a day (OR=0.70, 95%CI=0.49-1.00) were negatively associated with myopia. Conclusion There are different risk factors for myopia among different students in Shenzhen. Students with high risk factors are the key objects of prevention and control.

Objective: To investigate psychological sub-health status and its correlation with suicidal behaviors among middle school students in Shenzhen, so as to provide reference for early prevention of suicide. Methods: A total of 4 014 students from 5 junior high schools and 5 senior high schools in Shenzhen were selected as the subjects. The status of psychological sub-health and suicidal behaviors were assessed, and their correlation was analyzed. Results: The detection rates of psychological sub-health, suicide ideation, suicide plan and suicide attempts were 21.38%, 24.66%, 11.81% and 3.64% respectively. The detection rates of suicidal ideation, suicide plan and suicide attempts among students with high level of psychological sub-health status were significantly higher than those without psychological sub-health status(P<0.01). Correlation analysis showed that the number of psychological sub-health symptoms was positively correlated with the number of suicidal ideations, suicide plans and suicide attempts(P<0.01). Conclusion Psychological health status of adolescents in Shenzhen is not optimistic. There is a correlation between psychological sub-health status and suicidal behaviors. More attention should be paid to suicide prevention among students with psychological sub-health status.

Objective: To understand parent-child cohesion and problematic mobile phone use among middle school students in Shenzhen, and to provide a refevence for conducting the relevant control and prevention work . Methods: A total of 3 992 students from 5 junior high schools and 5 senior high schools in Shenzhen were selected by using stratified cluster sampling method. Problematic mobile phone use and parent-child cohesion were investigated, and their association was analyzed. Results: The average score of father-child cohesion and mother-child cohesion was (34.34±9.67) and (38.14±8.35), respectively. Mother-child cohesion score was higher than father-child cohesion score in both junior and senior middle school students(t=12.07, 14.41, P<0.01). Father-child cohesion (r=-0.20, P<0.01) and mother-child cohesion (r=-0.17, P<0.01) was negatively correlated with problematic mobile phone use. The lower the score of parent-child cohesion, the higher the score of problematic mobile phone use. Conclusion Family plays an important role in the prevention and control of problematic mobile phone use among middle school students. Improving parent-child cohesion and building a good parent-child relationship may help prevent problematic mobile phone use.

OBJECTIVE:To observe clinical efficacy and safety of Compound xiongshao capsules in the treatment of diabetic peripheral neuropathy (DPN).METHODS:A total of 97 DPN patients selected from our hospital during Jun.2015-Apr.2016 were divided into group A (compound xiongshao treatment group,46 cases) and control group (51 cases) according to random number table.The latter was divided into group B (epalrestat+beraprost sodium group,12 cases),group C (fursultiamine+mecobalamin group,12 cases) and group D (epalrestat group,27 cases) according to clinical symptoms and economic situation of patients.Four groups were given antidiabetic drugs for blood glucose control.Based on it,group A was additionally given Compound xiongshao capsules 0.9 g,tid;group B was additionally given Epalrestat tablets 50 mg,tid+Beraprost sodium tablets 40 μg,tid;group C was additionally given Fursultiamine tablets 50 mg,tid+Mecobalamin tablets 0.5 mg,rid;group D was additionally given Epalrestat tablets 50 mg,tid.All groups were treated for 6 months.Clinical efficacies were observed.TCSS scores,motor nerve conduction velocity (MCV),sensory nerve conduction velocity (SCV),incubation period and amplitude of median nerve and common peroneal nerve,the levels of hemorheology indexes,blood glucose,glycosylated hemoglobin,blood lipid,serum creatinine were compared before and after treatment.The occurrence of ADR was recorded.RESULTS:Total response rates of group A and B (82.61％,83.33％)were significantly higher than those of group C and D (33.33％,66.67％),total response rate of group D was significantly higher than that of group C,with statistical significance (P＜0.05).Before treatment,there was no statistical significance in TCSS scores,MCV,SCV,incubation period and amplitude of median nerve,MCV and amplitude of common peroneal never,SCV,incubation period and amplitude of common peroneal never or whole blood high-shear viscosity among 4 groups (P＞0.05).After treatment,TCSS scores of group A,B and D were decreased significantly compared to before treatment,and those of group A and B were lower than those of group C and D,with statistical significance (P＜0.05).MCV,incubation period and amplitude of median nerve in group A and B,amplitude of median nerve in group C,MCV and amplitude of median nerve in group D were significantly better than before treatment;MCV,incubation period and amplitude of median nerve in group A and B were significantly better than group C and D,with statistical significance (P＜0.05).MCV,incubation period and amplitude of common peroneal never in group A,B,C were significantly better than before treatment,MCV and amplitude of common peroneal never in group A,B were significantly better than group C,D;the improvement of incubation period of common peroneal never in group A,B,D were significantly better than group C,with statistical significance (P＜0.05).SCV,incubation period and amplitude of median nerve,SCV and amplitude of common peroneal nerve in group A,B and D were significantly better than before treatment;SCV,incubation period and amplitude of median nerve,SCV and amplitude of common peroneal nerve in group A,SCV,incubation period and amplitude of median nerve and amplitude of common peroneal nerve in group B were significantly better than group C and D;SCV of median nerve in group D was significantly better than group C,with statistical significance (P＜0.05).Whole blood high-shear viscosity of group A was decreased significantly compared to before treatment,and significantly lower than those of group B,C and D,with statistical significance (P＜0.05).There was no statistical significance in total response rate and TCSS score between group A and B,and in the levels of blood glucose,glycosylated hemoglobin,blood lipid or serum creatinine among 4 groups (P＞0.05).No obvious ADR was found in 4 groups.CONCLUSIONS:Compound xiongshao capsules shows significant therapeutic efficacy for DPN,and improves nerve conduction velocity,incubation period and amplitude of median nerve and common peroneal nerve,whole blood high-shear viscosity.Its effect is similar to that of epalrestat combined with beraprost sodium,and better than those of fursultiamine combined with mecobalamin,epalrestat alone.It does not affect the blood glucose,blood lipid and serum creatinine levels with good safety.

Objective To identify the species of Biomphalaria snails collected in Shenzhen reservoir,based on the mitochondrial 16S rDNA sequences.Methods The 16S rDNA fragments were amplified by PCR from the genome DNA of Biomphalaria snails,and inserted in plasmid pMD-18T for sequencing.The sequence of 16S rDNA fragment and its phylogenetic relationships with those of other species of Biomphalaria snails were analyzed with BLAST and MEGA4 software.Results The amplified 16S rDNA fragment of the Biomphalaria snails was about 466 bp in length.As aligned with the corresponding sequences of the related Biomphalaria species,the identity of nucleotides was 99％ with 1 isolate of Biomphaltria straminea (B.straminea),98％ with 3 isolates of B.kuhniana,95％ with 1 isolate of B.intermedia,and 94％ with 1 isolate of B.edisoni.Based on the 16S rDNA sequence,the results of phylogenetic analysis with neighbor-joining (NJ) and unweighted pair-group method with arithmetic means (UPGMA) indicated that the snails had close genetic relationships with the B.straminea isolate (Genbank accession NO.AY030213.1) Conclusion The Biomphalaria snails collected in Shenzhen reservoir could be classified as B.straminea based on the characteristics of 16S rDNA sequence.

Objective To analyze the correlation between genetic variants of PRF1 and expression level of perforin and granzyme B protein,and further determine the relationship between PRF1 gene variants and cytotoxic T lymphocyte/natural killer (CTL/NK) cell function in famililal hemophagocytic lymphohistiocytosis (FHL2).Methods Eight children of FHL2 (P1-P8) after treatment,as well as parents and siblings of P1-P5 were included,and thirty healthy children came for physical examination were designated as controls.PRF1,Unc13D,STX11,STXBP2,RAB27A,LYST,SH2D1A,BIRC4 exons were amplified by PCR and followed by direct sequencing.Bioinformatics analysis of mutant PRF1 was performed by ExPASy online system.Perforin and granzyme B expression on cytotoxic lymphocyte was detected by flow cytometry.Results ① Three of eight FHL2 children harbored heterozygous missense of PRF1 exons:P1 had compound heterozygous missense mutations (R4C and R33H) and P2 had heterozygous mutations (V50L),P3 had heterozygous mutations (R489W),which confirmed the diagnosis of FHL2.The father (F1) and younger brother (B1) of P1 also had compound heterozygous missense mutation (R4C/R33H),the mother (M2) and younger brother (B2) of P2 had V50L mutation,the father (F3) of P3 had no R489W mutation and the mother of P3 did not participate in this research,so mutation of R4C/R33H of P1 inherited from patemal line,and V50L mutation of P2 came from maternal line,R489W mutation of P3 came from maternal line.②Comparing to control group,perforin expression of CD8+ T cells and natural killer (NK) cells of P1,F1,B1,P2,M2 and B2 decreased significantly,but there was no significant difference between two groups in terms of granzyme B expression.Conclusions R4C/R33H compound heterozygous mutation and V50L heterozygous mutation all cause lower expression of perforin on CTL/NK cells,and may be causative mutations for familial hemophagocytic lymphohistiocytosis.

Biomphalaria straminea,the intermediary host of Schistosoma mansoni,was found by survey in local areas of Shen-zhen City in 1981,which was the first finding of the snail in inland China. By 2013,the snail had spread in large range of Shen-zhen City and overspread to the surrounding regions,Dongguan City and Huizhou City. Due to the facts that Shenzhen City has many international communications and is a key area of labor export,with high population mobility,while the reports of S. manso-ni infection in the returnees of our country from Africa have been increasing recently,it must be paid a high attention to whether the epidemic or transmission of schistosomiasis mansoni may happen under the present circumstance. This paper initially discusses the finding,distribution,spreading and overspreading and transmission risk of B. straminea in inland China and puts forward some related control suggestions.

Objective To investigate the antimicrobial resistance of main clinical isolates from ICU during 2012 .Methods Auto-matic microbiology analysis system and the disk diffusion method were performed to determine the antimicrobial susceptibility .All the data were analyzed by WHONET5 .6 software according to the breakpoints of The American Association of Clinical Laboratory Standardization Institute (CLSI) 2012 .Results A total of non-repeated 1 374 clinical isolates were collected in ICU during 2012 , including 1 089 strains (79 .3% ) of Gram-negative bacilli and 285 strains (20 .7% )of Gram-positive cocci ;The top five pathogens were Acinetobacter baumannii ,Pseudomonas aeruginosa ,Escherichia coli ,Klebsiella pneumoniae and Staphylococcus aureus ;Some Enterobacteriaceae strains were resistant to imipenem or ertapenem .2 strains of Enterococcus faecium were found resistant to van-comycin .Conclusion Non-fermenting bacteria ,Enterobacteriaceae and Staphylococci remain the predominant pathogens isolated from the patients in ICU ,their drug resistance is serious ,it is important to use antibacterial agents rationally and strengthen the sur-veillance of bacterial drug resistance .