Survey on the Construction Status of Forensic Virtual Autopsy Laboratory and the Applicability of Laboratory Accreditation / 法医学杂志

OBJECTIVES@#To survey the development status and actual needs of virtual autopsy technology in China and to clarify the applicability of forensic virtual autopsy laboratory accreditation.@*METHODS@#The questionnaire was set up included three aspects：(1) the current status of virtual autopsy technology development; (2) the accreditation elements such as personnel, equipment, entrustment and acceptance, methods, environmental facilities; (3) the needs and suggestions of practicing institutions. A total of 130 forensic pathology institutions were surveyed by online participation through the Questionnaire Star platform.@*RESULTS@#Among the 130 institutions, 43.08% were familiar with the characteristics of virtual autopsy technology, 35.38% conducted or received training in virtual autopsy, and 70.77% have establishment needs (including maintenance). Relevant elements were suitable for laboratory accreditation.@*CONCLUSIONS@#Virtual autopsy identification has gained social recognition. There is a demand for accreditation of forensic virtual autopsy laboratory. After the preliminary assessment, considering the characteristics and current situation of this technology, China National Accreditation Service for Conformity Assessment (CNAS) can first carry out the accreditation pilot of virtual autopsy project at large comprehensive forensic institutions with higher identification capability, and then CNAS can popularize the accreditation in a wide range when the conditions are suitable.

Strike Velocity Prediction of Stick Blunt Instruments Based on Backpropagation Neural Network / 法医学杂志

OBJECTIVES@#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.@*CONCLUSIONS@#The prediction model of BP neural network can meet the demand of predicting the maximum striking velocity of different populations.

Reconstruction and Quantitative Evaluation of Blunt Injury Cases by Finite Element Method / 法医学杂志

OBJECTIVES@#To reconstruct the cases of acceleration craniocerebral injury caused by blunt in forensic cases by finite element method (FEM), and to study the biomechanical mechanism and quantitative evaluation method of blunt craniocerebral injury.@*METHODS@#Based on the established and validated finite element head model of Chinese people, the finite element model of common injury tool was established with reference to practical cases in the forensic identification, and the blunt craniocerebral injury cases were reconstructed by simulation software. The cases were evaluated quantitatively by analyzing the biomechanical parameters such as intracranial pressure, von Mises stress and the maximum principal strain of brain tissue.@*RESULTS@#In case 1, when the left temporal parietal was hit with a round wooden stick for the first time, the maximum intracranial pressure was 359 kPa; the maximum von Mises stress of brain tissue was 3.03 kPa at the left temporal parietal; the maximum principal strain of brain tissue was 0.016 at the left temporal parietal. When the right temporal was hit with a square wooden stick for the second time, the maximum intracranial pressure was 890 kPa; the maximum von Mises stress of brain tissue was 14.79 kPa at the bottom of right temporal lobe; the maximum principal strain of brain tissue was 0.103 at the bottom of the right temporal lobe. The linear fractures occurred at the right temporal parietal skull and the right middle cranial fossa. In case 2, when the forehead and left temporal parietal were hit with a round wooden stick, the maximum intracranial pressure was 370 kPa and 1 241 kPa respectively, the maximum von Mises stress of brain tissue was 3.66 kPa and 26.73 kPa respectively at the frontal lobe and left temporal parietal lobe, and the maximum principal strain of brain tissue was 0.021 and 0.116 respectively at the frontal lobe and left temporal parietal lobe. The linear fracture occurred at the left posterior skull of the coronary suture. The damage evaluation indicators of the simulation results of the two cases exceeded their damage threshold, and the predicted craniocerebral injury sites and fractures were basically consistent with the results of the autopsy.@*CONCLUSIONS@#The FEM can quantitatively evaluate the degree of blunt craniocerebral injury. The FEM combined with traditional method will become a powerful tool in forensic craniocerebral injury identification and will also become an effective means to realize the visualization of forensic evidence in court.

Research Progress on MicroRNA in Forensic Medicine as Molecular Markers / 法医学杂志

MicroRNA （miRNA） belongs to a class of endogenous non-coding small RNA molecules with a length of 18-24 nucleotides. The expression of miRNA is highly conservative, has time sequence and is highly tissue-specific. MiRNA could not be easily degraded by ribonuclease, and is resistant to changes in environmental factors such as temperature and pH value. Moreover, miRNA can even be detected in corrupt tissue. As a result, miRNA has broad application prospects in many fields of forensic medicine such as source identification of body fluid and estimation of cause of death. This article briefly summarizes the application of miRNA in forensic practice, such as body fluid identification, determination of postmortem interval and cause of death analysis.

Advances in Neuropathologic Research of Hypoglycemic Brain Damage Caused by Insulin Overdose / 法医学杂志

The number of death from insulin overdose, including accidental poisoning, suicide and homicide, is increasing these years. The forensic diagnosis of death from insulin overdose is a tough task. Glucose is the main energy source of the brain. Therefore, hypoglycemic brain damage is considered to be the main reason of death from insulin overdose. Recently, research of hypoglycemic brain damage caused by insulin overdose is gradually being paid attention in the field of forensic medicine. This paper summarizes the neuropathologic changes, pathophysiologic process and potential neural molecular markers of hypoglycemic brain damage caused by insulin overdose in terms of forensic neuropathology, providing reference for the research and practice in forensic medicine related fields.

Application of OCT in the Forensic Pathological Diagnosis of Coronary Artery Atherosclerosis and Myocardial Infarction / 法医学杂志

OBJECTIVES@#To investigate the value of optical coherence tomography （OCT） in the diagnosis of coronary atherosclerosis and myocardial infarction in forensic identification.@*METHODS@#OCT and hematoxylin-eosin （HE） examination were performed to examine the pathological samples of coronary artery and myocardial infarction in 5 cases of sudden coronary death. The morphological and local measurement indexes were compared.@*RESULTS@#In the OCT images, the layers of coronary artery could be distinguishably featured, and the atheroma plaques had a good morphological correspondence with HE slices. The normal myocardia in the OCT image showed weak light signals with high absorbance, while the fiber scar tissues in the myocardial infarction areas showed strong light signals with low absorbance. There were no significant differences on the fibrous cap thickness in coronary atherosclerotic plaques or intima-media thickness between the OCT images and the HE slices （P>0.05）. In the OCT images, the optical densities of the old myocardial infarction areas （1 226.24±622.66） and those of normal myocardia （3 707.90±962.98） were significantly different （ P<0.05）.@*CONCLUSIONS@#The OCT image has a good morphological consistency with HE slice, thus is expected to be the primary screening method for the forensic pathology examination of coronary artery atherosclerosis and myocardial infarction, which can help to improve the diagnostic accuracy.

Advance in animal models of traumatic brain injury / 法医学杂志

Traumatic brain injury (TBI) is a highly complex multi-factorial disorder. Animal models of TBI are used to elucidate primary and secondary injury mechanisms and pathophysiological changes and to provide the diagnostic and therapeutical basis for TBI. The choices of animal models depend upon the research objectives. However, various animal models have limitations. The models only can duplicate the pivotal injury mechanisms or a certain important pathophysiological course. The characteristics of human TBI can not fully be reflected by using these models. In the review, animal models of traumatic brain injury are classified as dynamic direct brain injury, indirect dynamic brain injury and combined neuro-traumatic models. Several common models are described for consideration.

Relationship between expression of nestin in experimental brain contusion and injury time / 法医学杂志

OBJECTIVE@#To observe the alteration of nestin intervals in the experimental traumatic brain injury and investigate its relation to the injury intervals.@*METHODS@#The rat brain contusion was conducted by falling impact injury. After various survival interval (0.5, 6, 12 h and 1, 3, 7, 14, 28 d), immunohistochemical SP method was used for observing the expression of nestin in the cortex, hippocampal dentate gyrus and the corpus callosum on injury side.@*RESULTS@#Expression of nestin positive cells increased at 0.5 h and reached the maximum level in 7 d after brain contusion, then the expression decreased gradually. The intensity of nestin staining in the the cortex and the hippocampal dentate gyrus decreased to normal on 28 d. As to the corpus callosum of injury side it remained weak on 28 d.@*CONCLUSION@#The changes of nestin immunohistochemical staining can be used as an index for forensic estimation of early injury time.