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    Original Articles
    Strike Velocity Prediction of Stick Blunt Instruments Based on Backpropagation Neural Network
    Hai-yan LI, Hai-fang LI, Jian-yu PAN, Shi-hai CUI, Guang-long HE, Li-juan HE, Wen-le LÜ
    2022, 38(5): 573-578.  DOI: 10.12116/j.issn.1004-5619.2020.401108
    Abstract ( 223 )   HTML ( 28 )   PDF (1579KB) ( 481 )  

    Objective To analyze and predict the striking velocity range of stick blunt instruments in different populations, and to provide basic data for the biomechanical analysis of blunt force injuries in forensic identification. Methods Based on the Photron FASTCAM SA3 high-speed camera, Photron FASTCAM Viewer 4.0 and SPSS 26.0 software, the tester’s maximum striking velocity of stick blunt instruments and related factors were calculated and analyzed, and inputed to the backpropagation (BP) neural network for training. The trained and verified BP neural network was used as the prediction model. Results A total of 180 cases were tested and 470 pieces of data were measured. The maximum striking velocity range was 11.30-35.99 m/s. Among them, there were 122 female data, the maximum striking velocity range was 11.63-29.14 m/s; there were 348 male data, the maximum striking velocity range was 20.11-35.99 m/s. The maximum striking velocity of stick blunt instruments increased with the increase of weight and height, but there was no obvious increase trend in the male group; the maximum striking velocity decreased with age, but there was no obvious downward trend in the female group. The maximum striking velocity of stick blunt instruments has no significant correlation with the material and strike posture. The root mean square error (RMSE), the mean absolute error (MAE) and the coefficient of determination (R2) of the prediction results by using BP neural network were 2.16, 1.63 and 0.92, respectively. Conclusion The prediction model of BP neural network can meet the demand of predicting the maximum striking velocity of different populations.

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    Cooling Kinetic Characteristics of Temperature Difference between Cadaver Temperature and Ambient Temperature
    Xiao-fei DUAN, Zi-long GUO, Zhen YAO, Yin-di LIU, Hai HU, Zhou-yang HU
    2022, 38(5): 579-583.  DOI: 10.12116/j.issn.1004-5619.2021.411117
    Abstract ( 285 )   HTML ( 33 )   PDF (702KB) ( 510 )  

    Objective To study the cooling reaction kinetic characteristics of the temperature difference between cadaver temperature and ambient temperature (hereinafter referred to as “cadaver temperature difference”) according to the reaction kinetics method. Methods Thirty rabbits were randomly divided into 5 groups with 6 rabbits in each group. The rabbits were injected with 10% potassium chloride solution intravenously. After death, the rabbits were placed at 5 ℃, 10 ℃, 15 ℃, 20 ℃ and 25 ℃ environment condition, respectively, and the rectal temperature was measured every minute for 20 hours. The measured cadaver temperature was subtracted from ambient temperature, and the cadaver temperature difference data was calculated using the reaction kinetics formula. The linear regression equation was fitted for analysis, and the experimental results were applied to the temperature difference data of human body after death for verification. Results Under different environmental conditions, the linear coefficient determination of temperature difference -ln(C/C0) in rabbits was 0.99, showing a good linear relationship with time t. The application of human body temperature data after death was consistent with the results of animal experiments. Conclusion Under stable conditions, the temperature difference cooling process after death in rabbits is a first-order kinetic response. The method can also be used to study the temperature difference in human body after death.

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    Visualization of Literature Information on Postmortem Interval Estimation Indexed by CNKI Database from 1990 to 2020
    Ling-xiao LIN, Guo-bin XIN, Jiang-wei KONG, Chuang-yan ZHAI
    2022, 38(5): 584-588.  DOI: 10.12116/j.issn.1004-5619.2020.400902
    Abstract ( 320 )   HTML ( 21 )   PDF (1928KB) ( 609 )  

    Objective To explore the development process of the postmortem interval (PMI) research in China from January 1990 to August 2020, research hotspots in different periods, authors and cooperation between institutions, and to provide a reference for the better development of PMI inference research through the visualization of the literature information of the PMI estimation research indexed in China National Knowledge Infrastructure (CNKI). Methods The information visualization analysis software CiteSpace 5.7.R1 was used to carry out big data analysis on hotspots, high-frequency keywords, authors, institutions and other information in the research literature on PMI inference from January 1990 to August 2020 indexed in CNKI. Results The peak time of publication of PMI was from 2006 to 2010 with 114 articles. In keyword co-occurrence network, the effective hot words were forensic entomology, DNA content analysis and some emerging words such as artificial intelligence and big data. In the cooperation network of institutions, the high-frequency institutions were mainly the scientific research institutions. The author cooperation network showed a trend of co-aggregation and multi-cooperation. Conclusion With the development of science and technology, the research on PMI estimation based on traditional methods is mature and novel strategies are emerging. Big data and artificial intelligence combined with forensic science provide new research directions on PMI estimation.

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    Relationship between the Height of Alveolar Bone Resorption and Sex and Age in Adolescents
    Jing-jing MA, Min SHANG, Da-wei QIN, Wen-zhao REN, Jia-yin SHI, Xiao-yun ZHAO, Ze-wei YAO, Fan LI
    2022, 38(5): 589-594.  DOI: 10.12116/j.issn.1004-5619.2021.210301
    Abstract ( 282 )   HTML ( 26 )   PDF (746KB) ( 483 )  

    Objective To explore the relationship between the height of alveolar bone resorption and sex and age in the adolescent dentition. Methods Multi-slice computed tomography (MSCT) was used to measure the height of alveolar bone resorption at labial, lingual, mesial and distal sites of teeth in 149 adolescents aged from 10 to 20 years. SPSS 25.0 software was used to analyze the relationship between the height of alveolar bone resorption and sex and age. Results There was no significant difference in the height of alveolar bone resorption between sex (P>0.05). The height of alveolar bone resorption was positively correlated with age in all types of teeth. The model constructed by combining the alveolar bone resorption height data of four sites (y=2.569x1+3.106x2+4.108x3+1.451x4-0.082,R2max=0.756)had a better ability to infer age than that of combining two sites (y=5.942x1+4.489x2+0.612,R2max=0.706) and a single site (R2max=0.638). Conclusion The height of alveolar bone resorption is positively correlated with the age of adolescents. The combination of four sites has a stronger ability to infer the relationship between the height of alveolar bone resorption and age in adolescents and has higher accuracy in practical application.

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    Detection of Synthetic Cannabinoid CUMYL-PEGACLONE in E-Cigarette Oil and Hair
    Tai-feng JIAO, Ya-qing LI, Gang KANG, Shen-shu CHEN, Liang-hong CHENG
    2022, 38(5): 595-600.  DOI: 10.12116/j.issn.1004-5619.2022.320701
    Abstract ( 331 )   HTML ( 38 )   PDF (1112KB) ( 565 )  

    Objective To establish a combined high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and gas chromatography-mass spectrometry (GC-MS) method to detect the synthetic cannabinoid CUMYL-PEGACLONE in e-cigarette oil and hair. Methods HPLC-MS/MS and GC-MS were used to establish the detection method of CUMYL-PEGACLONE, and the hair of drug-involved persons and the seized e-cigarette oil were detected. Results The main mass spectrometry characteristic ions m/z of CUMYL-PEGACLONE measured by GC-MS were 91, 179, 197, 254 and 372. CUMYL-PEGACLONE had a good linear relationship in the mass concentration range of 2-50 ng/mL, and the linear correlation coefficient (r) was greater than 0.99. The limit of detection (LOD) of CUMYL-PEGACLONE in hair was 0.01 ng/mg, and the limit of quantitation (LOQ) was 0.02 ng/mg. The LOD of CUMYL-PEGACLONE in e-cigarette oil was 1 ng/mg, and the LOQ was 2 ng/mg. The average recoveries of CUMYL-PEGACLONE under the attempt at high, intermediate and low levels in blank human hair and e-cigarette oil matrix were 98.2%-132.4% and 93.5%-110.6%, and the intraday and intraday precision were 1.2%-12.9% and 0.7%-2.9%. CUMYL-PEGACLONE was detected in the hair of 15 drug-involved persons. Except for 1 person who was lower than LOQ, the concentration of CUMYL-PEGACLONE in the hair of other 14 persons was 0.035-0.563 ng/mg. The mass fraction of CUMYL-PEGACLONE in 2 e-cigarette oil were 0.17% and 0.21%, respectively. Conclusion The established HPLC-MS/MS and GC-MS methods are applied to the detection of HPLC-MS/MS in drug-related cases, which provides strong evidence support for the handling authority to quickly investigate these cases, and also provides a reference for the identification of such substances in future.

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    Postmortem Distribution and Postmortem Redistribution of Carbofuran-7-Phenyl Glucuronic Acid in Rabbits
    Yan WEN, Yu-zhe HAN, Duo GONG, Wen-kai XIE, Chen-xi LÜ, Yu-zhen MENG, Chao ZHANG, Zhi-wen WEI, Ke-ming YUN
    2022, 38(5): 601-605.  DOI: 10.12116/j.issn.1004-5619.2020.301204
    Abstract ( 157 )   HTML ( 7 )   PDF (669KB) ( 426 )  

    Objective To establish a carbofuran intragastric administration death model in rabbits, and to observe the postmortem distribution and postmortem redistribution of carbofuran-7-phenyl glucuronic acid (Glu-7PH) in rabbits. Methods The postmortem distribution: Rabbits were given an administration of 1/2LD50, LD50, 2LD50 carbofuran. Dead rabbits were dissected immediately. Rabbits that had remained alive 2 hours were sacrificed by carbon dioxide (CO2) inhalation and dissected immediately. The myocardium, cardiac blood, liver, spleen, lung, kidney, brain and right hindlimb muscle were collected. The postmortem redistribution: After giving an administration of 4LD50 carbofuran, the myocardium, cardiac blood, liver, spleen, lung, kidney, brain, and right hindlimb muscle were collected at 0, 12, 24, 48, and 72 h postmortem in supine position at 15 ℃ room temperature. The quantity of Glu-7PH was determined by LC-MS/MS. Results The postmortem distribution: Among the three dose groups, there were significant differences in the quantities of Glu-7PH in different tissues. The postmortem redistribution: There was no significant difference in the Glu-7PH quantities in cardiac blood, mycardium, spleen, kidney, brain and right hindlimb muscle, but there was a significant difference in the Glu-7PH quantities in the liver and lung. Conclusion The mycardium, cardiac blood, liver, lung, kidney, brain and hindlimb muscle of rabbits can be used as appropriate samples for Glu-7PH detection. However, it should be noted that Glu-7PH was redistributed postmortem in rabbit liver and lung.

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    The Legal Correspondence of Sexual Self-Defense Capability Assessment
    Hui-yu FAN, Hao-zhe LI, Qing-ting ZHANG
    2022, 38(5): 606-610.  DOI: 10.12116/j.issn.1004-5619.2022.120101
    Abstract ( 562 )   HTML ( 22 )   PDF (678KB) ( 470 )  

    Objective To understand the legal application and case deposition of assessment opinions of sexual self-defense capability, and to explore the necessity of legal correspondence in the sexual defense capability assessment. Methods According to the self-made questionnaire, the cases of sexual self-defense capability assessment completed by the Academy of Forensic Science from January 1, 2012 to December 31, 2018 were statistically analyzed through telephone interviews and referrals. Results Among the 69 cases, 3 cases (4.3%) had complete sexual self-defense capability, 30 cases (43.5%) had weakened sexual self-defense capability, 32 cases (46.2%) had no sexual self-defense capability, and 4 cases (5.8%) were not suitable for assessment. Among the 30 cases with weakened sexual self-defense ability, 15 cases were filed and investigated by public security authorities for rape and 15 cases were not. The inconsistent rate of disposition was 1∶1. Among the 15 rape cases filed and investigated by the public security authorities, 10 cases were arrested and prosecuted by the procuratorate and sentenced to fixed-term imprisonment by the court, while the other 5 cases were not arrested and prosecuted by the procuratorate, with an inconsistent rate of disposition being 2∶1. Conclusion The legal application of the assessment opinion on the weakening of sexual self-defense capability is inconsistent, and the judicial disposition is confusing. It is imperative to unify and correspond the classification of sexual self-defense capability with the legal requirements.

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    Technique and Application
    Optimization and Developmental Validation of 38-plex InDel Panel for Ancestry Inference
    Qing-guo WANG, Lei ZHAO, Tang-song LI, Wang FU, He-xin XIE, Yuan MA, Wen-ping SUN, Jun-ping HAN
    2022, 38(5): 611-617.  DOI: 10.12116/j.issn.1004-5619.2021.510105
    Abstract ( 147 )   HTML ( 9 )   PDF (2796KB) ( 411 )  

    Objective The previously established 38-plex InDel system was optimized and its performance was validated according to the Scientific Working Group on DNA Analysis Method (SWGDAM) application guidelines. The ancestry inference accuracy of individuals from East Asian, European, African and mixed populations was verified. Methods DNA standard sample 9947A was used as the template to establish the optimal amplification conditions by adjusting primer balance, Mg2+ final concentration and optimizing PCR thermal cycle parameters and amplification volume. The allelic dropout, nonspecific amplification and whether the origin of the inferred samples matched the known information were compared to evaluate the performance of this system. Results The optimal dosage of this system was 0.125-2 ng DNA template. The results of InDel typing were accurate, the amplification equilibrium was good, and the species specificity was good. This system showed certain tolerance to DNA samples including the inhibitor such as hemoglobin (≤80 μmol/L), indigo (≤40 mmol/L), calcium ion (≤1.0 mmol/L), and humic acid (≤90 ng/μL). The system enabled the direct amplification of DNA from saliva and blood on filter paper, and the results of ethnic inference were accurate. The system successfully detected the mixed DNA sample from two individuals. The test results of the system for common biological materials in practical cases were accurate. Conclusion The results of the 38-plex InDel system are accurate and reliable, and the performance of the system meets the requirement of the SWGDAM guidelines. This system can accurately differentiate the ancestry origins of individuals from African, European, East Asian, and Eurasian populations and can be implemented in forensic practice.

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    Review
    Research Progress on Sport-Related Sudden Cardiac Death
    Cheng-dong MA, Qiu-ping WU, Qian-hao ZHAO, Zhi-qiang ZHAO, Kun YIN, Nan ZHOU, Sai-qun WU, Jian-ding CHENG
    2022, 38(5): 618-624.  DOI: 10.12116/j.issn.1004-5619.2021.410407
    Abstract ( 412 )   HTML ( 41 )   PDF (687KB) ( 838 )  

    Physical exercise can reduce the overall risk of cardiovascular disease, prolong lifespan and improve the quality of life, but some studies have shown that there is a certain correlation between vigorous physical exercise and sudden cardiac death. A number of retrospective or prospective studies on sports-related sudden cardiac death (SrSCD) have been conducted at home and abroad. This article reviews the related studies on the definition, epidemiological characteristics, common causes of SrSCD and effects of excercise on cardiovascular function, pre-exercise screening and evaluation of SrSCD, in order to understand the latest research progress on SrSCD and provide clues and references for SrSCD research.

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    New Advances, Challenges and Opportunities in Forensic Applications of Microbiomics
    Fan-zhang LEI, Man CHEN, Shu-yan MEI, Ya-ting FANG, Bo-feng ZHU
    2022, 38(5): 625-639.  DOI: 10.12116/j.issn.1004-5619.2022.520303
    Abstract ( 691 )   HTML ( 33 )   PDF (1844KB) ( 842 )  

    The succession of microbiota is closely associated with several essential factors, including race, sex, health condition, lifestyle, postmortem interval, etc., and it has great potential application value in forensic medicine. This paper summarizes recent studies on the forensic applications of the microbiome, including individual identification, geographical feature identification, origin identification of the tissue or body fluid, and postmortem interval estimation, and introduces the current machine learning algorithms for microbiology research based on next-generation sequencing data. In addition, the current problems facing forensic microbiomics such as the extraction and preservation of samples, construction of standardization and database, ethical review and practical applicability are discussed. Future multi-omics studies are expected to explore micro ecosystems from a comprehensive and dynamic perspective, to promote the development of forensic microbiomics application.

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    Research Progress of Hyperspectral Imaging Technology in Biological Evidence
    Yi GAO, Tao HUANG, Jing-ru HAO, Yue MA
    2022, 38(5): 640-649.  DOI: 10.12116/j.issn.1004-5619.2021.510904
    Abstract ( 260 )   HTML ( 13 )   PDF (845KB) ( 471 )  

    Hyperspectral imaging technology can obtain the spatial and spectral three-dimensional imaging of substances simultaneously, and obtain the unique continuous characteristic spectrum of substances in a wide spectrum range at a certain spatial resolution, which has outstanding advantages in the fine classification and identification of biological substances. With the development of hyperspectral imaging technology, a large amount of data has been accumulated in the exploration of data acquisition, image processing and material inspection. As a new technology means, hyperspectral imaging technology has its unique advantages and wide application prospects. It can be combined with the common biological physical evidence of blood (stains), saliva, semen, sweat, hair, nails, bones, etc., to achieve rapid separation, inspection and identification of substances. This paper introduces the basic theory of hyperspectral imaging technology and its application in common biological evidence examination research and analyzes the feasibility and development of biological evidence testing and identification, in order to provide a theoretical basis for the development of new technology and promote hyperspectral imaging technology in related biological examination, to better serve the forensic practice.

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    Application Prospect of Integrative Omics in Forensic Identification of Methamphetamine-Associated Psychosis
    Long-rui ZHAO, Jian-bo ZHANG, Wei HAN, Li ZHU, Teng CHEN, Fang-lin GUAN
    2022, 38(5): 650-656.  DOI: 10.12116/j.issn.1004-5619.2021.101201
    Abstract ( 189 )   HTML ( 8 )   PDF (701KB) ( 543 )  

    The clinical symptoms and signs of methamphetamine-associated psychosis (MAP) and schizophrenia are highly similar, but the situation is completely different when MAP and schizophrenia patients need to be assessed for criminal responsibility after they comitted a harmful behavior. Therefore, the distinction between the two psychoses is very important in forensic psychiatry. At present, the identification of these two psychoses is mainly dependent on the corresponding criteria such as the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) and the Chinese Classification of Mental Disorders Version 3 (CCMD-3). It’s challenging to diagnose and distinguish between the two in practical cases due to their similar clinical symptoms and the lack of effective objective indexes. Different from the limitations of single omics, integrative omics intergrates data from multiple dimensions and has been extensively studied in the field of schizophrenia and has achieved some preliminary results. In view of the correlation between MAP and schizophrenia and the potential application value of integrative omics, this paper proposes an integrative omics strategy for MAP pathogenesis and forensic identification, aiming to improve the further understanding of the relationship between the two psychoses and the corresponding pathogenesis. It also provides references for the future exploration of integrative omics in forensic precise identification and effective monitoring and early warning methods.

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    Correction
    Editorial department of Journal of Forensic Medicine
    2022, 38(5): 583-583.  DOI: 10.12116/j.issn.1004-5619.2022.000001
    Abstract ( 172 )   PDF (1202KB) ( 293 )  
    Due to language barriers for non-native speakers, the authors of both articles in this journal were unaware of using inappropriate words in the English abstracts. The authors and the journal sincerely apologize for the errors made in the original versions. The correct descriptions in the Result section of the two abstracts should be as follows.
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