Objective To investigate the effects of three common anticoagulants,ethylene diamine tet-raacetic acid-K2(EDTA-K2),sodium citrate and heparin sodium,on the visual characteristics of blood-stains such as patterns and colors.Methods Freshly collected blood samples were treated with EDTA-K2,sodium citrate and heparin sodium respectively,and bloodstain samples were prepared on two ob-jects,acrylic plate and ceramic tile.Bloodstains without anticoagulant treatment were used as the con-trol sample.The drying time,wetting ratio,the number of cracks,the number of fragments,the cen-tral impression area ratio and the mean gray value of bloodstains were observed and recorded.Results Anticoagulants delayed the drying process of bloodstains.At 3.5 h,the wetting ratios of EDTA-K2-,sodium citrate-and heparin sodium-anticoagulated bloodstains on the acrylic plate were 54.80%,56.68%and 60.60%,respectively,which were higher than that of bloodstains without anticoagulant treatment(25.70%).Anticoagulants increased the number of cracks,the number of fragments and the central im-pression area ratio.The changes of these three visual characteristics were most obvious in the sodium citrate-anticoagulated bloodstains,with the crack number of 0.93/mm,the fragment number of 46,and the central impression area ratio of 48.41%after drying.Anticoagulants reduced the mean gray value of bloodstains.Among them,the sodium citrate-anticoagulated bloodstains exhibited the longest time to peak in mean gray value,reading 3.5 h.Similar changes in visual characteristics were observed on the ceramic tile.Conclusion The three commonly used anticoagulants change the visual characteristics of bloodstains.It is not recommended to use anticoagulated blood as a substitute for preparing experimen-tal samples in bloodstain pattern analysis experiments.Based on the changes in the visual characteris-tics during the drying process of bloodstains,the time of bloodstain deposition can be roughly esti-mated,and the blood scene staged with anticoagulated blood can be identified.

Objective To develop an SNP Panel for East Asian population, which has a high individual identification rate and the capability of ancestry analysis. Methods The 55 SNP Panel by Professor KIDD of Yale University and the 128 SNP Panel by Professor SELDIN of Davis School of California University, 170 SNP Panel in total was used as the basis and its test data in the East Asian population was collected. The genetic parameters of SNP loci were calculated and combined with the results of heatmap analysis to screen SNP loci suitable for East Asian population. Some Tibetan and Han samples were tested. The possibility of using the SNP loci in ancestry inference was analyzed by means of STRUCTURE analysis, principal component analysis and heatmap analysis. Results A Panel with 45 SNPs （45 SNP Panel） was screened out, and the average genetic parameters of each SNP were better than 170 SNP Panel, with the same ancestry analysis and inference ability. Conclusion In terms of ancestry inference information, the 45 SNP Panel can completely replace the 170 SNP Panel and achieve the same ancestry analysis and inference ability. In genetic parameters, 45 SNP Panel is better than 170 SNP Panel in the East Asian population, which shows its important potential forensic application value.
Asian People/genetics* ; Gene Frequency ; Genetics, Population ; Humans ; Polymorphism, Single Nucleotide ; Principal Component Analysis

Angiography, Digital Subtraction ; Arterial Occlusive Diseases ; diagnosis ; Carotid Artery Diseases ; diagnosis ; Carotid Artery, Internal ; pathology ; Carotid Artery, Internal, Dissection ; diagnosis ; Humans ; Male ; Middle Aged