Objective To establish a forensic age inference method based on age-related changes in maxillofacial CBCT imaging of Han population in North China.Methods CBCT imaging data of Han people aged 7～50 years were collected from September 2021 to September 2023.Mimics 17.0 software was used to perform 3D reconstruction on 480 cases that met the inclusion criteria(420 cases in the experimental group,60 cases in the blind test group,with a 50%male-to-female ratio)and obtain measured values for 16 indicators.The data were then statistically analyzed using SPSS 27.0 to identify age-related significant indicators and establish regression equations.Results Regression equations based on age-related significant indicators were established for different genders and age intervals.The accuracy of the equations decreased as the age interval increased.The blind test accuracy rates of regression equations for males across different age groups ranged between 62.6%and 80.6%,while for females,they ranged between 55.3%and 76.6%.Conclusion This study enriches maxillofacial skeletal data for Chinese population and establishes multivariate age inference regression equations based on significant indicators of age-related changes in maxillofacial CBCT,providing a new reference basis and inference method for forensic age assessment.

Objective To establish a forensic age inference method based on age-related changes in maxillofacial CBCT imaging of Han population in North China.Methods CBCT imaging data of Han people aged 7～50 years were collected from September 2021 to September 2023.Mimics 17.0 software was used to perform 3D reconstruction on 480 cases that met the inclusion criteria(420 cases in the experimental group,60 cases in the blind test group,with a 50%male-to-female ratio)and obtain measured values for 16 indicators.The data were then statistically analyzed using SPSS 27.0 to identify age-related significant indicators and establish regression equations.Results Regression equations based on age-related significant indicators were established for different genders and age intervals.The accuracy of the equations decreased as the age interval increased.The blind test accuracy rates of regression equations for males across different age groups ranged between 62.6%and 80.6%,while for females,they ranged between 55.3%and 76.6%.Conclusion This study enriches maxillofacial skeletal data for Chinese population and establishes multivariate age inference regression equations based on significant indicators of age-related changes in maxillofacial CBCT,providing a new reference basis and inference method for forensic age assessment.

Forensic medicine is the key force in crime scene investigations and identifications.It is also the traditional technique with the most personnel and the widest coverage of applications in criminalistics.Virtual autopsy is an innovative method of postmortem examination with high level scientific technology,high examining efficiency,and high digital value.Its unique advantages of non-invasiveness,digitalization,and reproducibility help to change the public's traditional concept of forensic autopsy.It can also improve the scientific and accuracy in identification of causes of death,help to accumulate data resources,and connect with the development of big data strategies and artificial intelligence in public security.Under the tide of developing new quality productive forces,forensic practitioners should focus on the opportunity of researches and practices on virtual autopsy.As a new quality identifying technology,virtual autopsy will strength the public security by fulfilling forensic mission and expanding medical-legal applications.

Forensic medicine is the key force in crime scene investigations and identifications.It is also the traditional technique with the most personnel and the widest coverage of applications in criminalistics.Virtual autopsy is an innovative method of postmortem examination with high level scientific technology,high examining efficiency,and high digital value.Its unique advantages of non-invasiveness,digitalization,and reproducibility help to change the public's traditional concept of forensic autopsy.It can also improve the scientific and accuracy in identification of causes of death,help to accumulate data resources,and connect with the development of big data strategies and artificial intelligence in public security.Under the tide of developing new quality productive forces,forensic practitioners should focus on the opportunity of researches and practices on virtual autopsy.As a new quality identifying technology,virtual autopsy will strength the public security by fulfilling forensic mission and expanding medical-legal applications.

Objective To quantitatively explore the influence of knife sharpness on forearm wounds in knife slash cases. Methods The finite element models of the upper limb and knives with 3 degrees of sharpness (with sharp blade, blunt blade, wide blade) were developed based on human CT images and prototype of slash knife. The slash by 3 kinds of knives on the forearm at velocity of 4 m/s and duration of 10 ms was simulated, so as to analyze changes in contact forces, wound dimensions and energy. Results During the slash by knives with sharp, blunt, wide blade, the blades reached the ulna at about 65, 85, 95 ms, respectively. The corresponding slash forces were 846, 1 064 and 1 865 N; the wound lengths were 135.64, 105.47 and 99.23 mm; the wound depths were 38.77, 27.81 and 18.74 mm. With the sharpness of blade decreasing, the wound formation was slowed, the length and depth decreased and the slash force increased. The model system for slash knife with sharp blade had obviously greater total energy and inner energy, but smaller kinetic energy, compared with slash knife with blunt blade and wide blade. Conclusions The method for quantitatively assessing wound formation in knife slash upon the forearm was developed. The research findings deepen the understanding of biomechanical mechanism of wound formation by knife slash, and provide new scientific means for forensic investigation and court trial of knife slash cases.

Objective To investigate the clinical use of blood in Shenzhen,in order to make the blood transfusion more appropriate and safer.Methods The medical records of 2 597 blood transfusion receipts from 3 hospitals in 2006 were reviewed.The use of blood components in each department,unreasonable prescriptions of very small amount of blood transfusion,and the combined transfusion of RBC and plasma were analyzed.Results The proportion of reasonable transfusion of RBC,plasma,platelet concentrates and cryoprecipitate were 66.44%,24.65%,97.97% and 61.29%,respectively.These proportion were 91.54%,51.85%,98.86%,and 100%,respectively,in internal medicine department,and 50.22%,19.86%,89.58%,42.86%,respectively,in surgery department.Unreasonable prescription of low-volume blood transfusion and the combined transfusion of RBC and plasma were 47.05% and 51.17%.Conclusion Except for plasma transfusion,the internal medicine departments did fairly well in blood component transfusion.Since the unreasonable transfusion still exists,the clinical doctors should be further trained in the appropriate use of blood,and get rid of the old practice of whole-blood-dependence.