With the development of molecular biology and genomics,metagenomics is playing a more important role in forensic science and forensic identification.In recent years,as a branch discipline studying the composition profile and diversity of microbe flora as well as studying the interaction within microbe and with environment,the application of metagenomics has gradually risen and brought new opportunities for forensic identification-related area.In this review,strategy of metagenomics and its application in forensic identification including individual identification,origin determination of biological stain in crime scene and drug abuse detection are summarized.This article aims to elucidate the role and application value of metagenomics in forensic science.

Objective To investigate the trend of BMI among adults in Shaanxi Province from 2007 to 2015. Methods Data was obtained from China Chronic Disease and Risk Factor Surveillance from 2007 to 2015, in which a multistage clustering sampling was adopted to collect a provincially representative sample of adults in Shaanxi Province. BMI percentile(P5, P25, P50, P75, P95) and the prevalence of underweight, overweight and obesity was calculated with weight in each survey. Cochran-Armitage test was used to test trends across survey periods. Changes in BMI across survey years were compared by considering the sampling weight. Results The results of the surveillance indicated that the prevalence of underweight decreased while overweight and obesity increased among adults in Shaanxi province (Z=-14.70, P<0.001). We observed the highest increase in the prevalence of overweight and obesity among rural residents and residents aged from18 to 44. The mean BMI was estimated to increase 0.176(t=3.00, 95%CI：0.055-0.298， P=0.006) per year. We found no difference in overweight and obesity ( 2=0.196，P=0.459) between 2013 and 2015. Conclusions We note increases in overweight or obesity and a decrease in underweight among adults in Shaanxi Province. Those living in rural areas and aged from 18 to 44 led the highest increase in overweight and obesity.

Objective:To develop and validate a model to predict the risk of malnutrition in patients with nasopharyngeal carcinoma receiving concurrent chemoradiotherapy. Methods:From April 2022 to August 2023, 430 patients with nasopharyngeal carcinoma who were admitted to the department of radiotherapy of the first affiliated hospital of Guangxi medical university in Nanning were conveniently selected as the study subjects, and they were divided into the modelling group (300 cases) and the internal validation group (130 cases) in the internal validation group in the ratio of 7:3, and 61 patients with nasopharyngeal carcinoma admitted to the affiliated cancer hospital of Guangxi medical university in Nanning City were selected as the external validation group. Logistic regression was used to establish the risk prediction model and draw nomograms,Hosmer-Lemeshow, calibration curve and ROC were used to verify the goodness of fit and predictive power of the model, and clinical decision curve was used to assess the clinical utility. Results:Logistic regression analysis showed that skeletal muscle mass index, self-rated anxiety scale score, Pittsburgh sleep quality questionnaire score, Chinese diet pagoda score, regular exercise, and digestive symptom groups were the influencing factors for malnutrition in patients with nasopharyngeal carcinoma receiving concurrent chemoradiotherapy. In the modelling group, the area under the ROC curve was 0.853 (95％CI:0.81 ～ 0.89), the maximum Youden was 0.600, and the corresponding specificity was 0.764 and the sensitivity was 0.836. The Hosmer-Lemeshow test=4.040 and P=0.853 indicated that the model had good predictive ability. Calibration curve of the calibration showed that the predictive effect of the model matched actual probability well, with an average absolute error was 0.024. When the threshold probability of the clinical decision curve is 0.05 ～ 0.85, the clinical response rate is higher. The area under the operating curve of the subjects in the internal validation group was 0.891, the sensitivity was 77.36％, the specificity was 89.61％, and the practical application accuracy was 84.62％. The area under the operating curve of the subjects in the external validation group was 0.886, the sensitivity was 76.00％, the specificity was 83.33％, and the overall accuracy was 80.33％. Conclusion:The risk prediction model constructed in this study has a good effect, which can effectively predict the incidence of malnutrition in patients receiving concurrent radiotherapy and chemotherapy for nasopharyngeal carcinoma, and provide a reference for clinical staff to formulate and implement nutritional interventions.

Objective To explore the expression and their significance of peripheral Th17 cells and regulatory T cells (Tregs) in idiopathic inflammatory myopathy,and analyze the relationship between the expression and clinical indicators,imaging and pathological changes.Methods Clinical data,laboratory tests,imaging and pathological changes of IIM cases (n=85) and healthy controls (n=70) were enrolled.Clinical data included the classification,age,gender,course of the disease;laboratory tests including erythrocyte sedimentation rate (ESR),C-reactive protein (CRP),creatine kinase (CK),creatine kinase isoenzyme-MB (CKMB),lactate dehydrogenase (LDH),hydroxybutyrate dehydrogenase (HBDH).The level of peripheral Th17,Treg cells and clinical indicators,laboratory tests,imaging and pathological changes were analyzed retrospectively.Since the data was disregarded from the normal distribution,the median four quantile method was used for statistical description.Two samples were compared with Mann-Whitney U test,and the correlation between variables was Spearman rank correlation analysis.Results ①) The levels of Th17 cells in the case group was not significantly different from that in the control group [6.18(3.42,13.65) cell/μl vs 7.42(5.02,11.13) cell/μl,P＞0.05],the levels of Treg cells in patients was significantly lower than that in the control group [21.25(12.48,35.67) cell/μl vs 36.95(30.37,47.12) cell/μl,P＜0.05],the ratio of Th17/Treg was also significantly higher than that in the control group [0.31(0.21,0.47) vs 0.18(0.14,0.31),P＜0.05].② Peripheral Treg cells levels were not correlated with ESR,CRP,CK-MB,LDH and HBDH (P＞0.05).Peripheral Treg cells levels were negatively correlated with CRP (r=-0.279,P＜0.05),but no correlated with ESR,CK-MB,LDH and HBDH (P＞0.05).③ According to the involvement of important organs,patients were classified into two groups:organ involvement group and non-organ involvement group.The levels of Treg cells in the organ involvement group was fewer than that in non-organ involvement group [16.54(8.84,27.34) cell/ul vs 24.87(14.44,43.37) cell/ul,P＜0.05],and the ratio of Th17/Treg in the organ involvement group was significantly higher than that in non-organ involvement group [0.41(0.29,0.68) vs 0.29(0.19,0.39),P＜0.05].④) Peripheral Th17 cells levels in patients with skeletal muscle inflammatory edema was significantly higher than that of non-inflammatory edema patients [10.70 (4.11,14.51) cell/μl vs 3.10 (1.27,5.15) cell/μl,Z=-2.460,P＜0.05].⑤ The levels of Th17,Treg cells and ratio of Th17/Treg did not correlate with pathological features of inflammatory infiltration (P＞0.05).Conclusion The absolute number of peripheral Treg cells decreases significantly in IIM,and correlates with CRP.Patients with organ involvement have fewer Treg cells,and there is imbalance between Th17 and Treg.When muscle MRI presents with inflammatory edema,patients may have high level of Th17 cells.Our results suggest that Treg cells may play an important role in the pathogenesis of IIM.