Identification of Human Body Fluid Stains and Non-Biological Stains by Three-Dimensional Fluorescence Spectroscopy / 法医学杂志

OBJECTIVES@#To establish a rapid and nondestructive identification method for human body fluid stains and non-biological stains using three-dimensional fluorescence spectroscopy.@*METHODS@#The collected three-dimensional fluorescence spectrum data of human saliva, 3% blood, coffee and Fanta® stains were processed with dimensionality reduction. After wavelet transform, spectral denoising and feature extraction, the classification formula was established. The Fisher discriminant was used for spectrum matching and recognition to establish the analysis method to distinguish stain types.@*RESULTS@#According to the results of data training and comparison, all the recognition accuracies of Fanta®, coffee, saliva and blood were more than 91.39%. Among them, saliva reached 100% recognition accuracy.@*CONCLUSIONS@#Three-dimensional fluorescence spectroscopy is a potential method for rapid and nondestructive identification of biological and non-biological stains.

Application Value and Research Progress of Human Microbiome in Sexual Assault Cases / 法医学杂志

In recent years, sexual assault cases have been on the rise, seriously infringing the legitimate rights and interests of women and children, causing widespread concern in society. DNA evidence has become the key evidence to prove the facts in sexual assault cases, but lack of DNA evidence or only DNA evidence in some sexual assault cases leads to unclear facts and insufficient evidence. With the emergence of high-throughput sequencing technology and the development of bioinformatics and artificial intelligence, new progress has been made in the study of human microbiome. Researchers have begun to use human microbiome for difficult sexual assault cases indentification. This paper reviews the characteristics of human microbiome, and its application value in the inferences of the body fluid stain origin, the sexual assault method, the crime time, etc. In addition, the challenges faced by the application of the human microbiome in practical case handling, the solutions and future development potential are analyzed and prospected.

Application and Prospect of RNA Profiling Analysis in Forensic Body Fluid Identification / 法医学杂志

In forensic physical evidence identification, the accurate identification of the individual origin and their body fluid composition of the biological samples obtained from the crime scene play a critical role in determining the nature of a crime. In recent years, RNA profiling has become one of the fastest developing methods for body fluids identification. Due to the characteristics of tissue or body fluid specific expression, various types of RNA markers have been proven to be promising candidate markers for body fluids identification in previous studies. This review summarizes the research progress of RNA markers in body fluids identification, including the RNA markers that have been effectively verified in current research and their advantages and disadvantages. Meanwhile, this review prospects the application of RNA markers in forensic medicine.

Preservação de vestígios forenses pela enfermagem nos serviços de emergência: revisão de escopo / Preservation of forensic traces by Nursing in emergency services: a scoping review / Preservación de los rastros forenses que realizan los enfermeros en los servicios de emergencias: revisión de alcance

Resumo Objetivo: mapear a produção científica sobre a preservação de vestígios forenses pelos profissionais de enfermagem que atuam nos serviços de emergência. Método: revisão de escopo, com buscas dos estudos realizadas em seis bases de dados, na literatura cinzenta disponível no Google Scholar e nas referências dos estudos selecionados. Para análise, adotou-se o método de redução de dados. Resultados: foram incluídos 26 estudos que foram organizados em cinco categorias: 1) Conhecimento dos profissionais de enfermagem sobre a preservação de vestígios forenses; 2) Procedimentos realizados pela enfermagem para preservação de vestígios no corpo da vítima; 3) Procedimentos realizados pela enfermagem para preservação de vestígios em pertences/objetos da vítima; 4) Procedimentos realizados pela enfermagem para documentação dos vestígios; e 5) Ações de manutenção da cadeia de custódia realizada pela enfermagem. Conclusão: os estudos mostraram situações em que o enfermeiro de emergência pode atuar na preservação de vestígios forenses presentes no corpo da vítima e em objetos, bem como no registro dos vestígios, verificando-se a atuação da enfermagem para garantir a integridade da cadeia de custódia, principalmente em situações de agressão, de ferimento com arma de fogo, violência sexual, abuso infantil e na assistência a vítimas de trauma.

Abstract Objective: to map the scientific production on the preservation of forensic traces by Nursing professionals working in emergency services. Method: a scoping review, with searches for studies carried out in six databases, in the gray literature available in Google Scholar and in the references of the studies selected. For analysis, the data reduction method was adopted. Results: 26 studies were included, organized into five categories: 1) Nursing professionals' knowledge on the preservation of forensic traces; 2) Procedures performed by Nursing to preserve traces in the victim's body; 3) Procedures performed by Nursing to preserve traces in the victim's belongings/objects; 4) Procedures performed by Nursing to document traces; and 5) Actions to maintain the chain of custody performed by Nursing. Conclusion: the studies showed situations in which the emergency nurse may act in the preservation of forensic traces present in the victim's body and in objects, as well as in the registration of traces, verifying the role of Nursing to ensure integrity of the chain of custody, especially in situations of aggression, firearm injury, sexual violence, child abuse and assistance to trauma victims.

Resumen Objetivo: mapear la producción científica sobre la preservación de rastros forenses por profesionales de enfermería que trabajan en los servicios de emergencias. Método: revisión de alcance, con búsqueda de los estudios realizados en seis bases de datos, en la literatura gris disponible en Google Scholar y en las referencias de los estudios seleccionados. Para el análisis, se adoptó el método de reducción de datos. Resultados: se incluyeron 26 estudios organizados en cinco categorías: 1) Conocimiento de los profesionales de enfermería sobre la preservación de rastros forenses; 2) Procedimientos que realizan los enfermeros para preservar rastros en el cuerpo de la víctima; 3) Procedimientos que realizan los enfermeros para preservar rastros en las pertenencias/objetos de la víctima; 4) Procedimientos que realiza el personal de enfermería para documentar los rastros; y 5) Acciones que llevan a cabo los enfermeros para mantener la cadena de custodia. Conclusión: los estudios demostraron que hay situaciones en las cuales el enfermero de emergencias puede actuar para preservar los rastros forenses presentes en el cuerpo de la víctima y en los objetos, así como también registrar los rastros, lo que comprueba la actuación del enfermero para garantizar la integridad de la cadena de custodia, particularmente en situaciones de agresión, heridas con arma de fuego, violencia sexual, abuso infantil y asistencia a víctimas de trauma.

Development and Forensic Application of EX20+30Y Kit / 法医学杂志

OBJECTIVES@#To develop a multiplex PCR amplification system (EX20+30Y for short) of 19 autosomes, 30 Y-STR loci plus the gender indicator, and evaluate its forensic application value.@*METHODS@#With the six-color fluorescence labeling technology, a multiplex amplification system of 19 autosomal STR loci and 30 Y-STR loci plus the gender indicator was constructed. Blood samples from 210 unrelated individuals, 69 daily case samples and standard samples 9948 and 9947A were collected for loci detection and analysis. The EX20+30Y multiplex amplification system was evaluated by its sensitivity, mixed sample detection ability, species specificity, balance, direct amplification ability, sample applicability and anti-inhibition ability.@*RESULTS@#Multiplex amplification of blood samples from 210 unrelated individuals by the detection system obtained accurate genotyping results. The detection sensitivity of standard samples was 0.125 ng and the species specificity was high. The 69 samples from daily cases were genotyped correctly. Moreover, standard sample 9948 could be accurately genotyped even if the samples contained a certain concentration of inhibitors.@*CONCLUSIONS@#The multiplex amplification system established in this study can conduct combined examination of 19 autosomes, 30 Y-STR loci plus the gender indicator with accurate genotyping and high sensitivity. It has a good forensic application prospect.

Image analysis of morphometric evaluation from the heart valves for age estimation in Thai population / Análisis de la evaluación morfométrica de las valvas cardíacas para la estimación de la edad en la población tailandesa

Determination of age represents one of the most important aspects in forensic identification. Through aging, changes can occur in morphological structures of the heart valves. The objective is to examine the relationship between the dimensions of the rigth atrioventricular (tricuspid), pulmonary, left atrioventricular (mitral), and aortic valves and age at death. Sixty fresh human hearts were obtained from Department of Anatomy and Department of Forensic Medicine, Faculty of medicine, Chiang Mai University, Thailand. The age of individuals was between 20-90 years. We investigated the morphometric parameters of the valves were taken including: valve circumference, length, the height and area of each leaflet. All parameters were measured by using specific image analysis software. The correlation test and predictive equation were established. The positive correlation between the circumference, area of posterior leaflet, height of anterior leaflet, and area of anterior leaflet of the rigth atrioventricular valve were found. The left atrioventricular valve showed correlation with age in circumference, length and area of posterior leaflet. For the pulmonary and aortic valves, there were correlated between circumference at sinotubular junction and leaflet sizes in almost leaflets. The circumference at sinotubular junction of the pulmonary valve was highest significantly correlation with age (r=0.693). The predictive equation was age = -3.659+0.652(Circumference at sinotubular junction of the pulmonary valve) with standard error of ± 14.7 years. Additional knowledge of morphometric features in human heart valves and its relationship with age could be used as age indicator in forensic field.

La determinación de la edad representa uno de los aspectos más importantes en la identificación forense. Pueden ocurrir cambios a través del envejecimiento, en las estructuras morfológicas de las válvulas cardíacas. El objetivo de este estudio fue examinar la relación entre las dimensiones de las valvas atrioventricular derecha (tricúspide), pulmonar, atrioventricular izquierda (mitral) y aórtica, y la edad en relación a la muerte. Se obtuvieron sesenta corazones humanos frescos del Departamento de Anatomía y el Departamento de Medicina Forense de la Facultad de Medicina de la Universidad de Chiang Mai, Tailandia. La edad de las personas fluctuaba entre los 20 y 90 años. Investigamos los parámetros morfométricos de las valvas analizadas, incluyendo: circunferencia de la valva, longitud, altura y área de cada valva. Todos los parámetros se midieron utilizando un software de análisis de imagen específico. Se estableció la prueba de correlación y la ecuación predictiva. Se encontró la correlación positiva entre la circunferencia, el área de la valvula posterior, la altura de la valvula anterior y el área de la valvula anterior de la valva atrioventricular derecha. La valva atrioventricular izquierda mostró correlación con la edad en la circunferencia, longitud y área de la valvula posterior. Para las valvas pulmonar y aórtica, se correlacionó entre la circunferencia en la unión sinotubular y el tamaño de las válvulas. La circunferencia en la unión sinotubular de la valva pulmonar fue la mayor correlación significativa con la edad (r = 0,693). La ecuación predictiva fue edad = -3,659 + 0,652 (circunferencia en la unión sinotubular de la valva pulmonar) con error estándar de ± 14,7 años. El conocimiento adicional de las características morfométricas en las valvas cardíacas humanas y su relación con la edad podría usarse como indicador de edad en el campo forense.

Parámetros forenses de diez microsatélites del cromosoma X en una muestra de la población del Estado Zulia, Venezuela / Forensic parameters of ten X chromosome microsatellites polymorphisms in a sample of the Zulia State population, Venezuela

Justificación:Las repeticiones cortas en tándem (STRs) están distribuidos por toda la extensión del genoma humano, los ubicados en los cromosomas autosómicos y en el cromosoma Y han sido ampliamente utilizados en los laboratorios de genética forense debido a las características y patrones hereditarios que estos poseen. ObjetivoA fin de caracterizar y determinar parámetros de interés forense en secuencias de tipo STR del cromosoma X (DXS8378, DXS9902, DXS7132, DXS9898, DXS6809, DXS6789, DXS7133, GATA172D05, GATA31E08 y DXS7423) en la población del Estado Zulia.Metodología:Se eligieron 108 individuos (130 cromosomas X),cuyos ADN se amplificaron mediante la reacción en cadena de la polimerasa, los fragmentos se separaron por electroforesis capilar y los alelos reportadoscon respecto a la escalera alélica. Resultados: El contenido de información polimórfica demostró ser mayor de 0,5 en todos los microsatélites y el poder de discriminación acumulado fue de 0,99999997 en mujeres y 0,99999816 en hombres.Conclusiones:Los datos demuestran que los microsatélites del cromosoma X analizados son lo suficientemente informativos como para ser utilizados en casos de vínculos biológicos complejos y la identificación humana...(AU)

Forensic Identification of Child Sexual Abuse / 法医学杂志

This paper reviews relevant literatures at home and abroad. The cases of child sexual abuse are systematically discussed from the aspects of epidemiology and forensic examination, in order to develop and improve the inspection and appraisal thinking and ability of domestic forensic workers in such cases. The paper also briefly introduces the current situation and existing problems of dealing with child sexual abuse cases for case-handling units at base level in China, in order to provide help to the formulation, improvement and development of relevant standards and norms for child protection in China.

Factors associated with child sexual abuse confirmation at forensic examinations / Fatores associados à confirmação por exame médico legal de abuso sexual infantil

Abstract The aim of this study is identify potential factors associated with child sexual abuse confirmation at forensic examinations. The forensic files of children under 12 years of age reporting sexual abuse at the Nina Rodrigues Institute of Forensic Medicine in Salvador, Bahia, Brazil between January 2008 and December 2009 were reviewed. A multivariate analysis was conducted to identify factors associated with finding evidence of sexual abuse in forensic examinations. The proportion of cases confirmed by the forensic physician based on material evidence was 10.4%. Adjusted analysis showed that the variables place of birth, type of abuse reported, family relationship between the child and the perpetrator, and the interval between the reported abuse and the forensic examination were not independently associated with finding forensic evidence of sexual abuse. A report of penetration was associated with a five-fold greater likelihood of confirmation, while the victim being 10-11 years of age was associated with a two-fold of abuse confirmation than younger children. These findings should be taken into consideration when drawing up guidelines for the multidisciplinary evaluation of children suspected of being victims of sexual abuse and in deciding whether to refer the child for forensic examination.

Resumo O Objetivo deste estudo é identificar potenciais fatores associados à confirmação de abuso sexual infantil no exame médico legal. Foram revisados os laudos de sexologia forense realizados em crianças menores que 12 anos que relataram abuso sexual no Instituto Médico Legal de Salvador, Brasil, no período de janeiro de 2008 a dezembro de 2009. Análise multivariada foi utilizada para identificar fatores relacionados à confirmação de abuso sexual pelo exame médico forense. A proporção de casos confirmados pelo médico legista com base em evidencia material foi de 10,4%. A análise ajustada demostrou que as variáveis naturalidade, tipo do relato de abuso, parentesco com o agressor, e intervalo entre o abuso relatado e a perícia não estão independentemente relacionadas à confirmação de abuso sexual em exame de corpo de delito. A presença de relato de penetração estava associada a uma chance cinco vezes maior de confirmação, e a faixa etária de 10 a 11 anos apresentou uma chance duas vezes maior de ter casos confirmados do que crianças menores. Estes dados devem ser levados em conta no planejamento de diretrizes para a avaliação multidisciplinar de crianças com suspeita de serem vítimas de abusos sexual e na decisão de encaminhamento para exame de corpo de delito.

Application of miniSTR Loci and Its Detection System for Degraded Materials in Forensic Medicine / 法医学杂志

OBJECTIVES@#To establish multiplex system of 16 miniSTR loci, and explore its application value for the degraded materials in forensic medicine.@*METHODS@#The multiplex system of 16 miniSTR loci was established using a six-dye fluorescence labeling technology and its application value in forensic medicine was assessed.@*RESULTS@#A six-dye fluorescence labeling miniSTR amplification kit was developed, which enabled 15 autosomal STR loci, Amelogenin locus and DYS391 to be typed simultaneously. This method showed good specificity and could provide stable and accurate typing results with a sensitivity of 50 pg. This system also provided a good test result for the normal biological sample of actual cases.@*CONCLUSIONS@#The multiplex system of 16 miniSTR loci has application value for degraded and trace materials with the advantages of high sensitivity and database compatibility, which can be used for forensic casework.

Contribuição da autopsia médico-legal para a investigação do acidente de trabalho fatal: relato de caso / Contribution of medico-legal autopsy to the investigation of fatal occupational accidents: case report

Os acidentes de trabalho são um importante problema de saúde pública. Embora entendidos como eventos não intencionais, podem ser previsíveis e preveníveis. Os institutos médico-legais desempenham importante papel na investigação de acidentes de trabalho fatais (ATF), pois todos os casos de morte violenta ou suspeita devem ser submetidos à necropsia forense. Este trabalho é um relato de caso necroscópico de ATF em que os dados obtidos na necropsia poderão contribuir para a melhor compreensão da dinâmica do ocorrido. Tratava-se de indivíduo do sexo masculino, com 34 anos de idade e suspeita de ter sido vítima de queda em ambiente de trabalho. Havia equimoses avermelhadas e arroxeadas no tórax, nos membros superiores e na região occipital do periciado. Na epiderme dos dedos das mãos foram observadas lesões cutâneas endurecidas, com destacamento parcial, que apresentavam aspectos macro e microscópico característicos de passagem de corrente elétrica em vida. Evidenciou-se fratura de crânio nos ossos parietal esquerdo e occipital, hemorragia subaracnoidea difusa, além de petéquias laríngeas, subpleurais e subepicárdicas. A pesquisa de alcoolemia e o exame toxicológico foram negativos. A causa do óbito foi traumatismo cranioencefálico contuso, tendo sido observados no periciado indícios de contato com corrente elétrica em vida. A autopsia permitiu melhor entendimento do mecanismo de morte e eliminou a possibilidade do trabalhador estar sob efeito de substâncias psicoativas no momento da ocorrência. Isso pode ser importante para a determinação da sequência dos eventos, auxiliando na implantação de medidas de prevenção.

Work accidents are a major public health problem. Although they are understood to be unintentional events, they are both predictable and preventable. Medico-legal institutes play a key role in the investigation of fatal work-related accidents (FWRA) because all cases of violent or suspicious death must be subjected to forensic autopsy. The present is a report of a case of FWRA in which autopsy contributed to a better understanding of the event's dynamics. The case concerns a 34-year-old man believed to have suffered a fall at the workplace. Examination revealed reddish and purple bruises on the chest, upper limbs and the occipital area, and hardened, partially detached epidermal lesions on the fingers, with the characteristic macro- and microscopic appearance of passage of electric current while alive. Fractures on the left parietal and occipital bones were found, as well as diffuse traumatic subarachnoid hemorrhage and laryngeal, subpleural and subepicardial petechiae. Blood alcohol and toxicology tests were negative. The cause of death was blunt head trauma, with signs of contact with electric current while alive. The autopsy therefore allowed for a better understanding of the mechanism of death, and ruled out the possibility of the worker having been under the effect of psychoactive substances at the time of event. Autopsy might be relevant to determine the sequence of events, thus contributing to the implementation of preventive measures.

Comparison of MPure-12 Automatic Nucleic Acid Purification and Chelex-100 Method / 法医学杂志

<p><b>OBJECTIVES</b>To explore the forensic application value of MPure-12 automatic nucleic acid purification （MPure-12 Method） for DNA extraction by extracting and typing DNA from bloodstains and various kinds of biological samples with different DNA contents.</p><p><b>METHODS</b>Nine types of biological samples, such as bloodstains, semen stains, and saliva were collected. DNA were extracted using MPure-12 method and Chelex-100 method, followed by PCR amplification and electrophoresis for obtaining STR-profiles.</p><p><b>RESULTS</b>The samples such as hair root, chutty, butt, muscular tissue, saliva stain, bloodstain and semen stain were typed successfully by MPure-12 method. Partial alleles were lacked in the samples of saliva, and the genotyping of contact swabs was unsatisfactory. Additional, all of the bloodstains （20 μL, 15 μL, 10 μL, 5 μL, 1 μL） showed good typing results using Chelex-100 method. But the loss of alleles occurred in 1 μL blood volume by MPure-12 method.</p><p><b>CONCLUSIONS</b>MPure-12 method is suitable for DNA extraction of a certain concentration blood samples．Chelex-100 method may be better for the extraction of trace blood samples．This instrument used in nucleic acid extraction has the advantages of simplicity of operator, rapidity, high extraction efficiency, high rate of reportable STR-profiles and lower man-made pollution.</p>

The Role of Segmental Analysis of Clonazepam in Hair in Drug Facilitated Cases / 法医学杂志

OBJECTIVES@#To infer the frequency of dosage and medication history investigate of the victims in drug facilitated cases by the segmental analysis of clonazepam in hair.@*METHODS@#Freezing milling under liquid nitrogen environment combined with ultrasonic bath was used as sample pretreatment in this study, and liquid chromatography-tandem mass spectrometry was used for the segmental analysis of the hair samples collected from 6 victims in different cases. The concentrations of clonazepam and 7-aminoclonazepam were detected in each hair section.@*RESULTS@#Clonazepam and its metabolite 7-aminoclonazepam were detected in parts of hair sections from the 6 victims. The occurrence time of drug peak concentration was consistent with the intake timing provided by victims.@*CONCLUSIONS@#Segmental analysis of hair can provide the information of frequency of dosage and intake timing, which shows an unique evidential value in drug facilitated crimes.

Application of Multiple Displacement Amplification in Samples with Inhibitors / 法医学杂志

OBJECTIVES@#To explore the ability of inhibition resistibility of multiple displacement amplification （MDA） in samples with inhibitors. To explain the application and value of MDA in forensic medicine by comparing with using magnetic beads methods （MBM） to purify sample.@*METHODS@#Different concentrations of hemoglobin and humid acid （HA） mixed with DNA samples and then divided the samples into MDA group, MBM group and control group. D3S1358 locus was amplified and detected by polyacrylamide gel electrophoresis detection system and AmpFℓSTR® Identifiler™ Plus Kit-capillary electrophoresis detection system.@*RESULTS@#When hemoglobin concentrations exceed 1 ng/μL or HA concentrations exceed 0.1 ng/μL, amplification products could not be obtained by single-locus system in control group. When hemoglobin concentration exceeds 100 ng/μL or HA concentrations exceed 1 ng/μL, the samples could not be amplified by MBM. Inhibitors in different concentrations were amplified successfully in MDA group without any influence from inhibitors.@*CONCLUSIONS@#MDA has the capability to remove the inhibition of hemoglobin and HA, which is better than MBM and has a certain value in forensic practices.

Bacterial Succession on Rat Carcasses and Applications for PMI Estimation / 法医学杂志

UNLABELLED@#Abstract:@*OBJECTIVE@#To investigate the bacterial succession on rat carcasses and to evaluate the use of bacterial succession for postmortem interval (PMI) estimation.@*METHODS@#Adult female SD rat remains were placed in carton boxes. The bacterial colonization of circumocular skin, mouth and vagina was collected to be identified using culture-dependent biochemical methods. The changes in community composition were regularly documented.@*RESULTS@#The bacterial succession in three habitats showed that Staphylococcus and Neisseria were predominated in early PMI, especially Staphylococcus aureus and Neisseria lactamica in 6 hours after death. Lactobacillus casei developed on the 3-4 days regularly, and kept stable at a certain level in late PMI.@*CONCLUSION@#The involvement of normal and putrefactive bacteria in three body habitats of rat remains can be used for PMI estimation.

Progress on Individual Stature Estimation in Forensic Medicine / 法医学杂志

Individual stature estimation is one of the most important contents of forensic anthropology. Currently, it has been used that the regression equations established by the data collected by direct measurement or radiological techniques in a certain group of limbs, irregular bones, and anatomic landmarks. Due to the impact of population mobility, human physical improvement, racial and geographic differences, estimation of individual stature should be a regular study. This paper reviews the different methods of stature estimation, briefly describes the advantages and disadvantages of each method, and prospects a new research direction.

Assessment of Function of a Single Limb after Injury / 法医学杂志

OBJECTIVE@#To explore the method for the objective evaluation of single limb function after in- jury in forensic medical practice.@*METHODS@#The score of activities of daily living (ADL) were graded for a single limb function after injury from 47 cases. All cases were simultaneously evaluated using the different methods including Fugl-Meyer motor function assessment (FMA), weighting, look-up table (LUT). The correlation were compared between ADL and the other three methods.@*RESULTS@#Injured part and the score using the three methods were correlated with ADL score (P < 0.05). The correlation coeffi- cient (|r| value) showed highest using LUT method, and lowest using FMA method.@*CONCLUSION@#The loss function of limb is affected by the injuried parts. The methods of FMA, weighting and LUT show a good accuracy for evaluating the limb function after injury and the correlation presents higher using LUT method.

Research Progress on Forensic Entomotoxicology / 法医学杂志

Forensic entomotoxicology is a branch of forensic medicine, which applies entomology, toxicology and other related studies to solve the poisoning cases. It has an obvious advantage in the investigation on poisoning death. Based on the expounding definition and research of entomotoxicology, this paper reviews research progress and application value in some aspects of forensic medicine, such as the effects of drugs/toxins on the growth and development of sarcosaphagous insects and the qualitative and quantitative analysis of the drugs/toxins in the poisoned body tissue.

Composition Analysis of Remaining Metal Particles on Ferrochrome Kitchen Knife / 法医学杂志

OBJECTIVE@#To establish a feasible evaluation index and method to identify composition of remaining metal particles on ferrochrome kitchen knife.@*METHODS@#The small samples of remaining metal particles were rubbed from the knives using filter paper. The composition of remaining metal particles was detected by scanning electron microscopy and energy dispersive X-ray spectrometer (SEM-EDX) and GSR particle analysis function, using mathematical methods to calculate the ratio (relative amount) of Fe and Cr in remaining metal particles.@*RESULTS@#The ratio (relative amount) of Fe and Cr of remaining metal particles had significant differences among most ferrochrome kitchen knives (P < 0.05).@*CONCLUSION@#Using GSR particle analysis function to quantitatively detect the ratio (relative amount) of Fe and Cr of remaining metal particles on ferrochrome kitchen knife, which can establish the feasible evaluation method to estimate such injury tool.

Simulation and Observation of Vertical Cast-off Bloodstain Pattern / 法医学杂志

OBJECTIVE@#To observe the characteristics of vertical cast-off bloodstain pattern by different hitting-tools.@*METHODS@#The regular hitting tools, a kitchen knife, a dirk, a plane set-hammer and an iron pipe, were selected. At a distance of 30 cm away from the wall, the hitting tool with 5 mL fresh chicken blood made the cast-off bloodstain from top to bottom. Then the holistic distribution characteristics (length, width and density) of cast-off bloodstain and morphology characteristics (length, width and contact angle) of first single cast-off bloodstain were analyzed.@*RESULTS@#The distribution length of cast-off bloodstain formed by dirk was minimum (P < 0.05). The distribution width of cast-off bloodstain formed by kitchen knife was minimum (P < 0.05). Except the pair of kitchen knife and plane set-hammer, the distribution density between each two tools had statistical differences (P < 0.05). The length of first single cast-off bloodstain formed by plane set-hammer was longest compared (P < 0.05). The width of first single cast-off bloodstain had statistical differences between kitchen knife and plane set-hammer, and between dirk and plane set-hammer (P < 0.05).@*CONCLUSION@#The type of hitting tool could be inferred by the specific characteristics of cast-off bloodstain pattern formed by every specific type of hitting tool in crime scene.