• YAKHAK HOEJI
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• v.57 no.2
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• pp.87-94
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• 2013

An analytical methodology based on solid-space extraction (SPE) with with Bond Elut Certify cartridge (Varian, 130 mg) has been developed for the qualification and quantitation of strychnine in blood. After the elution layer was evaporated, the residue was reconstituted with methanol for GC/MS. Internal standard was used 10 mg/l dextromethorphan. Strychnine is a potent central nervous stimulant and convulsant, and an alkaloid found in seeds of Strychnos nux-vomica. It was used therapeutically to improve circulation and muscle tone in oral or intramuscular doses of 0.05~8 mg. The fatal dose of strychnine for humans is 50~100 mg. A man was found dead lying curled up the corner of the large room in a roof house after the fire fighter opened a locked door inside to put out the fire. The postmortem blood and gastric contents were analyzed for toxicological testing. Strychnine and brucine were detected using GC/MS first in gastric contents extracts. The contents of strychnine was 0.083 mg/l in heart blood, 0.088 mg/l in peripheral blood and 4.0 mg/kg in gastric contents, respectively. Method validation was carried out in terms of linearity, accuracy, precision (intraday, interday) in blood. The assay is linear over 0.05~10 mg/l ($r^2$=0.999). Limit of detection (LOD) and limit of quantitation (LOQ) in blood were determined 0.02 mg/l (S/N=3) and 0.07 mg/l (S/N=10), respectively. Accuracy (bias%) of strychnine with 0.1, 1 and 10 mg/l was 12.0% (n=6), 9.3% (n=6) and 6.9% (n=6), respectively. Intraday precision (CV%) of strychnine with, 0.1, 1 and 10 mg/l were 6.4%, 10.4%, 1.2% (n=6), respectively. Interday precision (CV%) of strychnine with 0.1, 1 and 10 mg/l over three days were 24.0%, 18.5%, 13.8% (n=18), respectively. Relative recovery with 0.1, 1 and 10 mg/l (in blood) were 114.9%, 99.3% and 87.4% (n=6), respectively. The described method can be applied in forensic toxicology to determine strychnine in blood samples.

• Fire Science and Engineering
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• v.34 no.2
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• pp.94-96
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• 2020

In November 2013, a case of sustained combustion of a female body was encountered in a Korean farming village. The body was almost completely incinerated from the neck to the knees, and other parts of the body, such as the head, arms, lower legs, and feet, were slightly damaged. The most likely external ignition source was the flame from a matchstick. The elderly woman was found incinerated on the floor of the living room, while other objects in the house were largely undamaged except for having a brown oily or greasy coating. Flammable substances were not detected from the woman's intact pieces of clothing and socks, and her muscular tissues did not contain toxic chemicals. The concentration of carboxyhemoglobin in her peripheral blood was 11% and that of ethyl alcohol in her aqueous humor was below 0.010%. An autopsy failed to determine the exact cause of death because of excessive charring.

• YAKHAK HOEJI
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• v.52 no.3
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• pp.172-175
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• 2008

Stable isotope ratio of carbon and nitrogen ($\delta^{13}C$ & $\delta^{15}N$), and $\Delta^{9}$-tetrahydrocannabinol (THC) contents were measured on 37 Korean cannabis and 10 commercial grade marijuana seized in Korea. Factors influencing on the measured values and their variations were investigated. $\delta^{13}C$ value of cannabis is specified mainly by water availability. Korean cannabis showed relatively low $\delta^{13}C$ values ranging -33.29$\sim$-27.01% (mean=-31.01%), which reflect geographic conditions of Korea where is rainy, especially during summer. $\delta^{15}N$ values, which reflect individual planting conditions, were relatively high up to -0.5$\sim$18.0% (mean=6.44%). It reflects characteristics of Korean cannabis growing wild in forest or cultivated in fertile soil. Tetrahydrocannabinol is the major hallucinogenic compound of cannabis. Ethanol extracts of cannabis leaves were derivatized by N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA), and the derivatives were analyzed by GC-MS in selected ion monitoring (SIM) mode. THC contents of Korean cannabis ranged 0.11$\sim$4.34% (mean=1.47%), which were relatively low compared with commercial grade marijuana.

• Analytical Science and Technology
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• v.29 no.2
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• pp.79-84
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• 2016

A small and inexpensive thermal cycler (PCR machine), known as the MiniPCR^TM Mini8 Thermal Cycler (Amplyus, Cambridge, MA, USA), was developed. In this study, the performance of this PCR machine was compared with the GeneAmp^® PCR system 9700 (Applied Biosystems) using four autosomal short tandem repeat (STR) kits, a Y-chromosome STR kit, and a mitochondrial DNA HV1/HV2 sequence analysis. The sensitivity and stochastic effects of the STR multiplex kits and the quality of the DNA sequence analysis were similar between the two PCR machines. The MiniPCR^TM Mini8 Thermal Cycler could be used for analyses at forensic DNA laboratories and crime scenes. The cost of the PCR is so economical that school laboratories and individuals could use the machines.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.05a
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• pp.33-36
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• 2022

이벤트 로그(Event Log)는 윈도우 운영체제에서 시스템 로그를 기록하는 형식으로 시스템 운영에 대한 정보를 체계적으로 관리한다. 이벤트는 시스템 자체 또는 사용자의 특정 행위로 인해 발생할 수 있고, 그러한 이벤트 로그는 시스템의 시작과 종료뿐만 아니라 기업 보안 감사, 악성코드 탐지 등 행위의 근거로 사용될 수 있다. 본 논문에서는 PC 종료 관련 실험을 통해 이벤트 로그와 ID를 분석하였다. 분석 결과를 통해 PC의 정상 및 비정상 종료 여부를 판단하여, 현장 압수·수색 시 해당 저장매체에 대해 선별압수·매체압수의 해당 여부 식별이 가능하다. 본 연구는 현장수사관이 디지털증거 압수·수색 시 절차적 적법성과 증거능력 확보의 근거 활용에 기여할 수 있다.

• The Korean Journal of Legal Medicine
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• v.41 no.2
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• pp.41-45
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• 2017

Fetal DNA (fDNA) detection in maternal serum is a challenge due to low copy number and the smaller size of fDNA fragments compared to DNA fragments derived from the mother. Massively parallel sequencing (MPS) is a useful technique for fetal genetic analysis that is able to detect and quantify small amounts of DNA. In this study, seven clinical samples of maternal serum potentially containing fDNA were analyzed with a commercial single nucleotide polymorphism (SNP) panel, the HID-Ion $AmpliSeq^{TM}$ Identity Panel, and the results were compared to those from previous studies. Reference profiles for mothers and fetuses were not available, but multiple Y chromosomal SNPs were detected in two samples, indicating that fDNA was present in the serum and thereby validating observations of autosomal SNPs. This suggests that SNP-based MPS can be valuable for fDNA detection, thereby offering an insight into fetal genetic status. This technology could also be used to detect small amounts of DNA in mixed DNA samples for forensic applications.

• Analytical Science and Technology
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• v.36 no.4
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• pp.170-179
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• 2023

Starvation, diabetes, alcoholism and hypothermia cause ketoacidosis in the human body; therefore, the cause of death can be determined by analyzing ketone bodies in the blood of the deceased. In the case of decomposition of the cadaver, however, since collecting intact blood is impossible, ketone body analysis is performed using the spleen. However, the index for diagnosing ketoacidosis is based on blood concentration, and its correlation with ketone bodies present in the spleen remains unknown. In particular, since decomposition proceeds rapidly during summer, when temperature and humidity are high, understanding the correlation between ketone bodies in the blood and spleen is important to estimate the state at the time of death from a decaying body. Therefore, in the present study, the correlation between ketone bodies in the blood and spleen of the deceased was explored. Ketone bodies (beta-hydroxybutyric acid [BHB] and acetone) in the blood and spleen were analyzed and compared from autopsies (>100 mg·L^-1 BHB, blood basis) conducted at the Daejeon Forensic Research Institute from June to December 2021. Moreover, the concentration of ketone bodies in the spleen juice and tissues was compared assuming the scenario of extreme decomposition. Ketone retention concentration in the blood and spleen was positively correlated, and the ratio of BHB concentration in the spleen to BHB concentration in the blood ranged from 0.52 to 1.08 (mean = 0.85 ± 0.12), although the ratio may vary depending on the degree of decomposition of the corpse.

• Biomedical Science Letters
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• v.29 no.4
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• pp.302-313
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• 2023

Y chromosomal short tandem repeat (Y-STR) markers have been developed continuously to complement forensic DNA analyses and population genetic studies. Initially, we collected data from previously reported Korean population Y-STR haplotype studies on 1133 individuals. We then conducted a marker expansion analysis using a dataset from the Y-STR Haplotype Reference Database (YHRD), covering up to 29 Y-STRs, referred to as Ymax. Additionally, we examined the impact of rapidly mutating (RM) Y-STRs included in this expanded marker set on the discrimination capacity. We observed that marker expansions both with (0.9896), and without (0.9510), RM Y-STR improved the discrimination capacity. Subsequently, we focused on 16 individuals belonging to seven distinct groups sharing identical haplotypes. These particular haplotypes had been previously identified among 476 unrelated males using 23 Y-STR markers from the PowerPlex^® Y23 System. We expanded the marker panel up to Ymax to explore how discrimination improved with an expansion of Y-STR markers for these 16 individuals. Among the expanded markers, DYS627, which had high discriminatory power, had a high mutation rate (1.10 × 10^-2) and high gene diversity (0.83). In contrast, DYF387S1 displayed high gene diversity (0.95) but a relatively low mutation rate (2.80 × 10^-3). We propose that these findings will be valuable in the selection of suitable Y-STR markers, depending on the objectives of forensic analyses. Additionally, the presence of frequently observed Y-haplotypes in Korean population will facilitate statistical interpretation in Y-STR DNA profiling.

• Analytical Science and Technology
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• v.26 no.5
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• pp.340-351
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• 2013

The chemical element and structural characterization of different types of cements and its brick stones are been investigated under forensic aspects using X-ray florescence (XRF) and X-ray diffraction (XRD) spectrometer. The XRF provides rapid compositional data for controlling almost all stages of raw materials, clinker and cement. The decisive advantage of XRD methods is based on the unique character of the diffraction patterns of crystalline substances, the ability to distinguish between elements and their oxides, and the possibility to identify chemical compounds, polymeric forms, and mixed crystals by non-destructive examination. Therefore, combination of these examinations is useful and able to apply for the forensic analysis in comparison of cements and brick stones. There are more study remained to determine the viability of method for forensic analysis of brick stones and the limits of the discrimination that can be achieved.

• Analytical Science and Technology
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• v.31 no.2
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• pp.71-77
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• 2018

Detection of bloodstains is a very important process in scientific investigations, and luminol is often used for the detection of bloodstains that are not visible. Recently, new preparation methods of blood detection reagents based on luminol (BloodFlareA, B) were developed and reported to have higher active persistence and to be more economical than conventional blood detection reagent, BlueStar forensic. In this paper, we tested the specificity and effect of the BloodFlares (A and B) on DNA and compared them with those of BlueStar forensic. False positive results for the BloodFlares were not observed in semen, saliva, vaginal fluids, urine, sweat, and nasal discharge, but were observed in $CuSO_4$, $FeSO_4$, and bleach solutions, and the observed patterns were similar to those of BlueStar forensic. The effect on DNA was determined by analyzing the DNA yield, degradation index, and DNA profiling. Based on these results, we concluded that the BloodFlares based on luminol do not affect DNA stability and are applicable in forensics.