Earticle

Currently, fire investigation lack liveliness because they are performed based on photographs taken. Therefore, in this paper, we propose a method utilizing the metaverse to improve the validity of fire investigation. The fire scene was recreated by gathering the point cloud data of the 3D scanner, matching them, and then post-processing the matched data. In addition, a virtual space was created by an engine and VR equipment, with the addition of UI(User interface) and assets, to apply the created point cloud. With this method, it is expected that the validity of fire investigation will improve with a more vivid recreation of the fire scene through the metaverse.

In the course of installing an additional LPG fuel system which includes a high-pressure pump drilling in a gasoline engine system. leakage of fuel may be caused by operator error or component detect. If the gas leakage continuously occurs while a certain driving period, the leaked gas may cause an explosion and a fire by an ignition source. In this paper it introduces an explosion case of a gasoline engine vehicle with additional LPG fuel system. Depending on the location and amount of leaked gas, it could lead a huge and major accident. Therefore, we hope to share the case and take appropriate institutional measures for the various cause of the accident.

There is a function that describing the severity of vehicle’s accident by (changes of speed in the center of gravity of vehicle, km/h), impact point of the collision vehicle, the impacted point, and EES(Energy Equivalent Speed, km/h) using depth of impacted vehicle and the energy loss of the vehicle. CNN(Convolutional Neural Networks) is mainly used in Deep-learning to process image or video data. Convolution is a Neural Network model before preprocessing task. In PC-Crash V 13.0 has a EES-CNN function using EES and CNN. When user inputs image file of damaged vehicle, EES-CNN shows predicted  with a bar graph. To utilize this EES-CNN function in real accident-analysis, it has to be verified or needs improvements. In this study, after collecting images from NHTSA NASS-CDS in frontal collision condition, then verified if predicted data matches to Δυ data from NASS. Furthermore we analyzed property of pictures and presented a method of taking a picture for EES-CNN function to get higher accuracy.

Species identification has been performed using morphological features and molecular techniques between each species. Recently, advances in machine learning technology have been applied to animal and plant identification based on deep learning approach with images. In this study, we constructed the deep learning model to predict 16 species of marine ragworms using the Teachable Machine which is a web-based tool. We have trained the deep learning model with 865 images including key characters of 16 species and measured prediction accuracy using 3-fold cross validation. The results showed 94% sensitivity, 99% specificity, and 99% accuracy. The deep learning model for marine ragworms is freely available at forensicdna.kr/ML/ nereididae.

Generally, DNA of crime scene evidence is obtained from body fluids such as blood, semen and saliva. The detection and identification of body fluids are the most important step in forensic investigation. Especially, the determination of semen is very significant in case of sexual violence. Prostatic acid phosphatase test as the presumptive test for searching presence of semen is commonly used because of its convenience and cost/time-effectiveness. In this study, we tried to figure out the effect of AP reagent on DNA analysis according to the time dividing into two groups, control and experimental (AP reagent reaction). The degree of DNA condition was evaluated by the DNA concentration, degradation index and STR analysis. The result of degradation index of experimental group is higher than the control group. Also, in STR analysis, peak height and peak height ratio (PHR) of experimental group is lower than the control group increasing the effect of AP reagent on DNA analysis over time. Therefore, we confirmed that it is necessary to be cautious using the AP reagent on the whole of forensic evidence for high-quality DNA analysis.

Electron ionization-gas chromatography/mass spectrophotometry (EI-GC/MS) is generally used in searching for methcathinone (MCT) analogs. However, the spectrum of EI-GC/MS is difficult to interpret in new psychoactive substances (NPS) that are not registered in GC/MS libraries. There is also a risk of confusion because of the many candidate structures for fragment ions. By using our method, 13 kinds of MCT analogs can be classified into 26 different kinds of fragment ions based on typical and basic fragment ions. In addition, we compared the measured molecular weight (MW) and predicted the structure for the fragment ions of MCT analogs based on the candidates of the structures for their ions by EI-GC/MS and Orbitrap-EI-GC/MS. As a result of the analysis by EI-GC/MS, the MW was measured only up to the first digit. This made it difficult to specify the structure because there are many possible candidates. Whereas in the analysis by Orbitrap-EI-GC/MS, the MW was accurately measured up to the fifth digit. In addition, since the analysis only specified one type of candidate, it could be predicted accurately. Sulfur, iron, chlorine, and bromine, which are compounds with halogen or high isotope ratios, were also clearly distinguished in the analysis by Orbitrap-EI-GC/MS. In conclusion, when unknown NPS evidence is requested, it will be possible to predict the structure more quickly using chemical structural marker-based identification of MCT analogs by Orbitrap-EI-GC/MS. Therefore, this analysis will be useful to prevent the abuse of NPS.

The castor bean plant (Ricinus comminis), is the only known source of the toxin ricin. Ricinine is an alkaloid present in the castor bean plant that can be used as a biomarker for ricin poisoning. There are only a few reports on the quantitative determination of ricinine in human’s biological samples including intoxication cases. In the present study, we developed a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method with simple protein precipitation for sample extraction. Using this method, we performed a quantitative determination of ricinine in postmortem blood of a woman who was dead in her house after taking several castor beans. The validation parameters including linearity, accuracy, precision, matrix effect, and recovery were satisfactory. The concentration of ricinine in the victim’s blood was 35.3 ng/mL. This method can be usefully used for the determination of ricin poisoning in forensic field and emergency medical treatment system.

Formaldehyde was quantitatively analyzed by on fiber derivatization in biological tissues and fluid. It was sampled by derivatization with α-(2,3,4,5,6-pentafluoro benzyl-hydroxyamine hydrochloride(PFBHA) adsorbed onto polydimethylsiloxane/divinylbenzene (PDMS/DVB) solid phase microextraction fiber. We determined the optimal conditions of formaldehyde analysis with derivatization and adsorption by GC/MS. At first, PFBHA was loaded onto the fiber by headspace method in an aqueous PFBHA solution at room temperature for 5 min. One milliliter or gram of standards or biological tissues was placed in a 10 mL headspace vial and was heated for 20 min at 70 ℃. The PFBHA-loaded SPME fiber was introduced into the headspace for 40 min with agitation and then analyzed. The standard calibration curve was linear between 0 ~ 10.0 μg/mL of formaldehyde concentration with a correlation coefficient of 0.99. In the actual case of finding the human remains in Hyehaw-dong, formaldehyde was detected in the range of 0.46 ~ 4.76 μg/g in various tissues. Therefore, it suggested that these human remains were specimens of medical center of university.

Fluoride compounds through ingestion, inhalation or skin contact hydrolyze to fluoride ion and form corrosive hydrofluoric acid on the mucosa, and also act as a direct cellular poison which interferes with calcium metabolism and enzyme mechanisms to induce hyperkalemia and hypocalcemia, following to dysrhythmias and cardiac arrest. Although fluoride compound is very important substance in forensic science, it is one of the substances that are difficult to be identified by a routine toxicological analysis among all chemicals in the forensic case caused by "unknown" substance or a workplace chemical accident. Identification of fluoride compound often goes beyond the general analytical procedure, so a more systematic procedure should be suggested. This study reviews the analytical results of fluoride compound-related accident cases submitted to the National Forensic Service and presents improved analytical plans. In the case reviewed, hydrogen fluoride, sodium fluoride, ammonium fluoride, sodium fluorosilicate, calcium fluoride, nitrogen trifluoride were identified. These six types of fluoride compounds are suggested as accident preparedness substances that should be considered in forensic analysis of hazardous chemical accident in Korea.

Aluminum phosphide is a fumigant used to kill insects or other animals in stored grains. We report a suicidal case using aluminum phosphide and phosphine gas was detected in the post-mortem specimen. Headspace gas chromatographic method with mass detector(HS-GS/MS) was used to detect phosphine from the gastric contents and the scene evidence.

Venlafaxine (VEN) is a type of serotonin-norepinephrine reuptake inhibitor. It is known that the pharmacogenetics of VEN is mainly affected by metabolizer status of the Cytochrome P450 (CYP) 2D6 and CYP2C19 enzymes. We investigate a fatal overdose case of VEN in relation to CYP2D6 and CYP2C19 genetic polymorphisms. Qualitative and quantitative analyses for VEN were performed using gas chromatography-mass spectrometry and it is subsequently confirmed using ultra-high-performance liquid chromatography-tandem mass spectrometry. Genetic analysis for CYP2D6 and CYP2C19 polymorphism was performed using polymerase chain reaction (PCR) followed by DNA sequencing. The result was determined to be a fatal overdose of VEN in a Korean man with CYP2D6 heterozygous genotype *1/*2 that did not affect enzyme activity and wild allele of CYP2C19. The use of genotyping of CYP2D6 and CYP2C19 may assist interpretation for a considerable fatal dose of VEN in individuals with different CYP2D6 genotypes.

Traffic accidents are caused by various causes such as human factors : carelessness of vehicle drivers, etc, vehicle defects : braking system defects, etc and environmental factors. It is required to identify whether the accident is caused by careless of the driver or vehicle defect because of the legal responsibility of the driver. This case is an accident which the vehicle named chairman drove backwards on the road after refueling at a gas station and crashed into the wall of a building 200m away, and the driver claims it was a sudden acceleration accident due to a vehicle defect. Through the trace of the accident vehicle, trace formed on the driver's shoes, vehicle inspection and CCTV analysis, it is determined that the accidents are caused by carelessness of the driver who press the accelerator by mistake. If a similar case occurs in the future, it is thought to it can be used to determine the cause of the accident.