Earticle

This study performed molecular genetic identification using DNA barcode markers such as internal transcribed spacer(ITS) marker and nuclear large subunit(nLSU) marker in ribosomal DNA regions on 51 mushroom specimens which were previously classified as poisonous mushrooms according to the morphological identification method in Rural Development Administration(RDA). As a result, nine of the 51 mushroom specimens were identified as different species from the previously identified species, and one of them was identified as edible and medicinal mushroom, not as a poisonous mushroom. Based on the results of this study, it is considered that more accurate species identification results can be obtained by performing molecular genetic identification method using DNA barcode marker as well as morphological identification method in mushroom species identification.

Analysis of the DNA typing is used an important tools for identification of decomposed cadavers. Recently according to the technology development in the forensics biology, even if the sample is small or decomposition, it becomes possible to identify the individual through new genetic marker and DNA typing techniques. In this experiment, skeletal muscle, costal bone, vessels, achilles tendon, toenails, and molar were collected from 10 decomposed cadavers to analyze the DNA quantitative analysis and the DNA typing. Experimental results showed that the most stable DNA recovery was possible in costa bone, toenails, and skeletal muscles in the quantitative value of DNA. In some samples, more DNA could be recovered from the toenails than from the costal bone. In the DNA typing, the genotype were detected in all samples of costal bone, vessels, and toenails. In addition to the costal bone, DNA analysis of the toenails and other tissue revealed the possibility and should be first collected during DNA typing.

The forensic DNA database was managed according to the °ΠAct on the Protection and Use of DNA Identification Information°π enacted in July 2010, and the integrity and accuracy of the genetic information registered in this forensic DNA database was being emphasized. In this study, we analyzed the discordance (DC) ratio for each short tandem repeat (STR) locus in 21,160 samples received from January 2016 to October 2019 in order to contribute to improving integrity and accuracy of data. In addition, we also analyzed the change in DC ratio for each STR locus after the expansion of 20 core STR locus based on Combined DNA Index System (CODIS) of the FBI laboratory in January 2018. As a result, the DC ratio for each STR locus increased from 29 cases to 67 cases according to the expansion of the STR locus, and we selected the STR loci with a high DC ratio. Also, we were able to organize the three types of DC occurrence in this study. These results suggest that may help to minimize the STR data analysis error of crime scene evidence samples and to increase the reliability of the forensic DNA database.

One purpose of this study was to develop and validate a quantitative LC-MS/MS method for the analysis of vortioxetine and its carboxylic acid metabolite, and the other purpose is to obtain a therapeutic range of vortioxetine by applying it to the plasma of the actual medicine takers. The targetcompounds were measured with liquid chromatography-tandem mass spectrometry (LC-MS/MS) after deproteination. The LC system was coupled to a 4500 QTrap mass spectrometer using electrospray ionization in positive mode and multiple reaction monitoring (MRM) mode. The column was Kinetex XBC18 column. The method showed acceptable precision and accuracy, which were less than 12%, as well as satisfactory matrix effects and recoveries. The concentrations of vortioxetine and carboxylic acid of vortioxetine in plasma of the actual medicine takers were 3.23 ng/mL ~ 63.8 ng/mL and 3.63 ng/mL ~ 46.9 ng/mL, respectively. In conclusion, this LC-MS/MS method can be a sensitive and specific protocol for determining vortioxetine and its carboxylic acid metabolite in human plasma. Also vortioxetine concentration results of actual medicine takers can be considered as a good reference when evaluating vortioxetine toxicity.

Methanol is the simplest alcohol that is widely used as a precursor to other commodity chemicals, fuel for vehicles, solvent, and etc. Fatal cases were caused by intentional ingestion or accidental drinking, and accidental exposure happened by absorption through skin or respiratory tracts in workplace. Also, as methanol is known to be contained at the concentration of 50-350 mg/L in wine and 13-106 mg/L in distilled liquor, good care must be taken not to be intoxicated. Methanol is rapidly absorbed from the gastrointestinal tract, and then metabolized to the toxic substances, formaldehyde and formic acid. In this study, formic acid was analyzed in blood samples from three fatalities due to drinking methanol using ion chromatography. The concentrations of formic acid in heart and peripheral bloods were 415-685 mg/L and 491-582 mg/L, respectively, and the formic acid levels from all the three cases were included within the lethal concentration range.

Pentobarbital belongs to barbiturates and is a drug used for general anesthesia and seizures. Although barbituric acid derivatives have been a major medicine for anxiety and insomnia in the past, they have been largely replaced by benzodiazepines due to serious central nervous system toxicity and fatal interactions with other drugs. Pentobarbital is currently produced as an injection for anesthesia in Korea, but it is used for euthanasia in some countries. The overdosage of pentobarbital may lead to respiratory depression, hypotension, coma and death. Therefore, some cases that pentobarbital was purchased through the internet or black market and used as a suicidal application had been reported. In this study, we encountered recently four suicidal cases of pentobarbital poisoning. The identification of toxic substances was requested in their biological specimens and the scene evidences. Pentobarbital was detected in biological specimens, and the concentrations of it were ranged from 42.0-431.0 mg/L in heart blood and 18.0-60.0 mg/L in peripheral blood, respectively. From the four cases, pentobarbital was detected as lethal concentration in the blood and large amounts far exceeding the recommended dosage were detected in the gastric contents. Along with pentobarbital, metoclopramide, a gastrointestinal function modifier, was detected in the biological specimens from three cases, and nitrous oxide, a recreational drug, was detected in scene evidences from one case. It was believed that the fatalities died from pentobarbital intoxication, and methoclopramide was taken together as an anti-vomiting agent.

Pigments used in traditional oriental paintings were basic materials for colors, mainly natural Seokchae, artificial Seokchae, Bunchae, etc. Artificial Seokchae, used since modern times, is still mainly used today. Pigment component for 52 each and 24 each of artificial Seokchae from N company and R company sold on the market in Korea, respectively, was analyzed by non-destructive methods such as spectrometry, Polarization microscopy, XRF and XRD. It has been confirmed that artificial Seokchae(Shinarmchae) was produced by finely dispersing powdered artificial pigments in lead glass or glass with a high refractive index to make the color and texture similar to that of natural Seokchae which was produced in powder form of colored minerals. However, in the R company’s products, there were many pigments in which Pb was not detected, which is thought to have used a glass material whose main component is Si instead of lead glass. Transition elements such as Cr, Co, Sb, Fe, Sn were detected as elements showing major coloring properties. Also, as for the main color components, Pb2Sb2O7, Cd(S,Se), CaSn(SiO4)O, Zn2SiO4, CoAl2O4,(Al,Cr)2O4, CoCr2O4, Fe2(Fe, Cr)O4, Fe2O3,(Zr,V)SiO4, (Ti, Ni, Sb)O2, (Sn, Sb)O2 were detected according to the color in artificial Seokchae.

It is difficult to distinguish fingerprints found in a crime scene with the naked eye. So, the latent fingerprints development method was developed. And advanced methods are still developing these days. Reagents which react with fingerprint substances are usually used for the development of latent fingerprints. To evaluate a new reagent for the development of latent fingerprints, comparing with existing reagents are needed. However, conventional methods cannot generate fingerprints of the same type and cannot be applied to non-porous surfaces. In this study, a lipid component was added to an amino acid solution to develop an artificial fingerprint composition applicable to both porous and non-porous surfaces, and evaluated using real reagents.

In various violent crime cases, blunt instruments accounts for approximately 50 % among direct hit criminal tools, causing injury, especially bruising, in the event of a physical impact. In this study, the prediction of bruising stress and the influence of the blunt instrument in terms of diameter and aspect ratio of bruise was analyzed based on the human material mimesis. Two material behavior models (quasi-linear viscoelastic model and Ogden model) were verified for human material mimesis. A finite element analysis in relation to the impact was performed according to diverse threat factors, and the influence of threat factors on the bruise were elucidated via an analysis of variance. As a result, the difference between the results of the finite element analysis and those of experiments reported in references was an average 11.7 %. Therefore, it was confirmed that the quasi-linear viscoelastic model and the Ogden model described the behavior of human material adequately. By comparing the bruise diameters obtained from the finite element analysis with the those in references, it was found that the bruise occurred when 23~30 MPa of von Mises stress was applied to the epidermis and dermis. In addition, the velocity of the blunt instrument was the most dominant influencing factor to the diameter of the bruise whereas the shape of the blunt instrument had the greatest effect on the aspect ratio of the bruise. It is believed that the range of the bruising stresses presented in this study may help predict and identify bruise in body, and an analysis methodology between the threat factors and the bruises based on the statistical technique can be utilized as a generic technique of forensic investigation.

In this study, the combustion patterns and the causes of ignition in electric kickboard fire accidents were analyzed. Due to the thermal runaway of the Li-ion battery, The pour pattern and flight of flames characteristics appeared, which are characterized by forming an organic solvents and an independent ignition sites, It is hoped that it will be used as an investigation data for similar accident analysis. The tendency to occur in the state of 100 % charged SOC were shown, but the correlation with the charging environment is low. Pyrolysis or thermal factors of the electrolyte during the charging process seem to be relevant. In view of the characteristics and examples of electric kickboard fire and firefighting standards, It is necessary to classify the appropriate fire risks for Li-ion batteries.

Postmortem formation of alcohol is a well-known problem in forensic toxicology. N-propyl alcohol(n-PrOH) is important in deciding whether the ethyl alcohol(EtOH) is produced by putrefaction. It still has limitations in interpreting the alcohol consumption, although EtOH/n-PrOH (< 20) has been widely viewed as a marker of putrefaction. As non-oxidative metabolites of ethanol, ethyl glucuronide(EtG) and ethyl sulfate(EtS) have been used in indicating whether the alcohol was consumed in postmortem. This study was to assess the reliability of EtG and EtS in alcohol source distinction in postmortem case. For our routine method, EtOH and n-PrOH were analyzed on the headspace-gas chromatography with flame-ionization(HSGC- FID), the experiment of EtG and EtS was extracted with Amicon® Ultra 3kDa, and performed in liquid chromatography-tandem mass spectrometry (LC-MS/MS). In the result, the concentration of EtOH in the blood was 0.091%, n-PrOH was 0.0018%, EtOH/n-PrOH ratio was 50.5, and both EtG and EtS were below the low of detection(LOD; EtG 0.01 mg/L, EtS 0.004 mg/L). This study showed that EtOH/n-PrOH ratio led to false result of alcohol source distinction in the blood of postmortem, due to the opposite result with that of EtG and EtS. In conclusion, this case result showed that postmortem formation of alcohol was suspected.