• Analytical Science and Technology
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• v.21 no.4
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• pp.338-343
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• 2008

Extraction of DNA from skeletal material is of great importance in the identification of human remains, but is particularly difficult because the high amount of microbial DNA was often co-extracted with human bone DNA. We found that a phenol/chloroform extraction, followed by ultrafiltration, and cleanup by via the $QIAquick^{(R)}$ PCR purification kit yields higher amounts of human genomic DNA compared with extraction by the column affinity $method^{(R)}$ alone. Ultrafiltration extraction of human DNA from ten exhumed bone samples yielded $0.041-1.120ng/{\mu}L$ DNA (mean = $0.498ng/{\mu}L$ DNA), and purification using the column affinity resulted in $0.016-0.064ng/{\mu}L$ DNA (mean = $0.034ng/{\mu}L$ DNA). Although the STR genotyping by the column affinity method was partially successful, all DNA samples by the ultrafiltration method produced full profiles from the multiplex PCR. The efficiency of STR genotyping was in accordance with the amounts of the human DNA extracted.

• Korean Journal of Culture and Social Issue
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• v.14 no.4
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• pp.1-18
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• 2008

The present study examined the accuracy of polygraph tests through two types of statistical methods with unknown ground truth. One method evaluated the accuracy based on the rates of agreements between polygraph test results of crime suspects and prosecutors' indictment decisions for them. Those crime suspects were tested with polygraph by the Prosecutors' Office of the Republic of Korea between 2000 and 2004. The other method estimated the accuracy by using the latent class analysis based on the frequency distributions of the polygraph results and indictments during 2006. Excluding cases that were 'inconclusive' on the polygraph test, the study showed that the accuracy of the polygraph tests is .914 (SE=.004) for the 2000-2004 data, and .885 (SE=.021) for the 2006 data. With the inclusion of 'inconclusive' cases in the 2006 data, the results from the latent class analysis showed the accuracy in the range between .707 and .734 (SE=.027~.031), with false positives between .078 and .087 (SE=.019~.023), and false negatives between .029 and .078 (SE=.010~.023). The probability that the polygraph test correctly classifies subjects appeared to be in the range between .912 and .925 (SE=.013-.016) for those who lie, and in the range between .867 to .955 (SE=.011-.040) for those who tell the truth.

• Journal of Korean Society of Forest Science
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• v.112 no.4
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• pp.554-560
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• 2023

To prevent illegal timber distribution, DNA markers have been used to identify the species and origin. However, extracting high-quality DNA from timber is difficult because of its physical and chemical properties. In this study, we investigated whether the age of timber tissue influences the yield of DNA extraction and the success rate of polymerase chain reaction (PCR) to understand the relationship between the establishment time of the wood annual ring and the extracted DNA concentration (ng/μl), purity (A260/A280), and PCR success rate (%) from pinewood, a major Korean domestic species. According to the results, it was observed that as the distance from the cambium increased, indicating that the tissue was older, the concentration and purity of the extracted DNA decreased significantly. For the trnM-trnV (285 bp) and rpoC1 (298 bp) regions, the PCR success rate was 100%. However, for the rbcL (1.3 kb) region, the PCR success rate was 66.67%. Moreover, PCR amplification of the rbcL region failed at all points older than 30 years. Thus, it is deduced that as time passes, along with the decay of timber cells, DNA is degraded, leading to a decrease in DNA concentration, purity, and PCR success rate. The results of this study are expected to be beneficial for future applications, such as the species identification of timber, providing valuable insights and potential utilization in this field.

• Journal of Internet of Things and Convergence
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• v.9 no.6
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• pp.23-28
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• 2023

Windows operating system generates various logs with timestamps. Timestamp tampering is an act of anti-forensics in which a suspect manipulates the timestamps of data related to a crime to conceal traces, making it difficult for analysts to reconstruct the situation of the incident. This can delay investigations or lead to the failure of obtaining crucial digital evidence. Therefore, various techniques have been developed to detect timestamp tampering. However, there is a limitation in detection if a suspect is aware of timestamp patterns and manipulates timestamps skillfully or alters system artifacts used in timestamp tampering detection. In this paper, a method is designed to detect changes in timestamps, even if a suspect alters the timestamp of a file on a storage device, it is challenging to do so with precision beyond millisecond order. In the proposed detection method, the first step involves verifying the timestamp of a file suspected of tampering to determine its write time. Subsequently, the confirmed time is compared with the file size recorded within that time, taking into consideration the performance of the storage device. Finally, the total capacity of files written at a specific time is calculated, and this is compared with the maximum input and output performance of the storage device to detect any potential file tampering.

• Korean Journal of Materials Research
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• v.33 no.10
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• pp.406-413
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• 2023

This study used optical and scanning electron microscopy to analyze the surface oxidation phenomenon that accompanies a γ'-precipitate free zone in a directional solidified CM247LC high temperature creep specimen. Surface oxidation occurs on nickel-based superalloy gas turbine blades due to high temperature during use. Among the superalloy components, Al and Cr are greatly affected by diffusion and movement, and Al is a major component of the surface oxidation products. This out-diffusion of Al was accompanied by γ' (Ni₃Al) deficiency in the matrix, and formed a γ'-precipitate free zone at the boundary of the surface oxide layer. Among the components of CM247LC, Cr and Al related to surface oxidation consist of 8 % and 5.6 %, respectively. When Al, the main component of the γ' precipitation phase, diffused out to the surface, a high content of Cr was observed in these PFZs. This is because the PFZ is made of a high Cr γ phase. Surface oxidation of DS CM247LC was observed in high temperature creep specimens, and γ'-rafting occurred due to stress applied to the creep specimens. However, the stress states applied to the grip and gauge length of the creep specimen were different, and accordingly, different γ'-rafting patterns were observed. Such surface oxidation and PFZ and γ'-rafting are shown to affect CM247LC creep lifetime. Mapping the microstructure and composition of major components such as Al and Cr and their role in surface oxidation, revealed in this study, will be utilized in the development of alloys to improve creep life.

• Journal of the Korea Institute of Military Science and Technology
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• v.27 no.4
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• pp.507-515
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• 2024

Microbial forensics is a scientific discipline for analyzing evidence related to biological crimes by identifying the origin of microorganisms. Multiple locus variable number tandem repeat analysis(MLVA) is one of the microbiological analysis methods used to specify subtypes within a species based on the number of tandem repeat in the genome, and advances in next generation sequencing(NGS) technology have enabled in silico anlysis of full-length whole genome sequences. In this paper, we analyzed unknown samples provided by Robert Koch Institute(RKI) through The United Nations Secretary-General's Mechanism(UNSGM)'s external quality assessment exercise(EQAE) project, which we officially participated in 2023. We confirmed that the 3 unknown samples were B. anthracis through nucleic acid isolation and genetic sequence analysis studies. MLVA results on 32 loci of B. anthracis were analysed by using genome sequences obtained from NGS(NextSeq and MinION) and Sanger sequencing. The MLVA typing using short-reads based NGS platform(NextSeq) showed a high probability of causing assembly error when a size of the tandem repeats was grater than 200 bp, while long-reads based NGS platform(MinION) showed higher accuracy than NextSeq, although insertion and deletion was observed. We also showed hybrid assembly can correct most indel error caused by MinION. Based on the MLVA results, genetic identification was performed compared to the 2,975 published MLVA databases of B. anthracis, and MLVA results of 10 strains were identical with 3 unkonwn samples. As a result of whole genome alignment of the 10 strains and 3 unknown samples, all samples were identified as B. anthracis strain A4564 which is associated with injectional anthrax isolates in heroin users.

• Annals of Occupational and Environmental Medicine
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• v.35
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• pp.39.1-39.14
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• 2023

Background: Diseases affecting the lungs and airways contribute significantly to the global burden of disease. The problem in low- and middle-income countries appears to be exacerbated by a shift in global manufacturing base to these countries and inadequate enforcement of environmental and safety standards. In Ghana, the potential adverse effects on respiratory function associated with occupational wood dust exposure have not been thoroughly investigated. Methods: Sixty-four male sawmill workers and 64 non-woodworkers participated in this study. The concentration of wood dust exposure, prevalence and likelihood of association of respiratory symptoms with wood dust exposure and changes in pulmonary function test (PFT) parameters in association with wood dust exposure were determined from dust concentration measurements, symptoms questionnaire and lung function test parameters. Results: Sawmill workers were exposed to inhalable dust concentration of 3.09 ± 0.04 mg/m³ but did not use respirators and engaged in personal grooming habits that are known to increase dust inhalation. The sawmill operators also showed higher prevalence and likelihoods of association with respiratory symptoms, a significant cross-shift decline in some PFT parameters and a shift towards a restrictive pattern of lung dysfunction by end of daily shift. The before-shift PFT parameters of woodworkers were comparable to those of non-woodworkers, indicating a lack of chronic effects of wood dust exposure. Conclusions: Wood dust exposure at the study site was associated with acute respiratory symptoms and acute changes in some PFT parameters. This calls for institution and enforcement of workplace and environmental safety policies to minimise exposure at sawmill operating sites, and ultimately, decrease the burden of respiratory diseases.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.4
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• pp.579-585
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• 2015

The objective of this study was to investigate the quality characteristics of coffee soaked in Morus bombycis extract. Green coffee beans were soaked in M. bombycis extract for 2, 4, and 6 hours (sample codes: 2H, 4H, and 6H) at $4^{\circ}C$. Soaked green beans were dried and roasted for coffee extraction. Two controls, roasted with the same amount of heat (C1) and showed the same weight after roasting (C2), were used. Physicochemical characteristics (pH, total acidity, color, browning index, and total soluble solids), DPPH free radical scavenging activity (DPPH), ferric-reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), total polyphenol content (TPC), and total flavonoid content (TFC) were investigated. Lower pH and higher total acidity were observed in 2H, 4H, and 6H (P<0.05), supporting evidence of sour taste. There were significant differences in DPPH between the controls (45.51~47.02%) and samples (50.67~55.25%, P<0.05), although 2H and 6H did not show significantly higher DPPH than the controls. 2H, 4H, and 6H showed significantly higher FRAP values ($0.320{\sim}0.331\;FeSO_4{\cdot}7H_2O\;mM\;FeSO_4/g$) than controls ($0.265{\sim}0.271\;mM\;FeSO_4/g$). ORAC values of samples [1,062.86~1,153.68 mM trolox equivalent (TE)/g] were significantly higher than those of controls (689.40~942.12 mM TE/g). 2H, 4H, and 6H showed significantly higher TPC [24.27~26.07 mg gallic acid equivalent (GAE)/g] and TFC [3.75~4.28 mg quercetin equivalent (QE)/g] than controls (19.79~22.77 mg GAE/g and 1.07~1.95 mg QE/g, respectively) (P<0.05). M. bombycis extracts soaked into green coffee beans showed polyphenol compounds from green coffee beans. Consumer acceptance of 4H (5.12) was the highest, followed by C2 (4.92). C1 (4.14) showed the lowest consumer acceptance. Consumers were segmented into two groups, those who preferred M. bombycis extract-soaked coffee (approximately 61%) and controls (approximately 39%).

• Korean Journal of Social Welfare
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• v.39
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• pp.350-373
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• 1999

The patient population of U. S. state mental hospitals has changed drastically since the 1960s, when the deintstitutionalization movement began. This paper is designed to look at what happened to the number of inpatients of state hospitals in California during the last 150 years and, from this, to explore implications for the future of the mental health system in Korea, especially for the viability of mental hospitals. The data had been collected by field research(visits to state hospitals and State Department of Mental Health, and interviews with mental health administrators) and accessing statistical publications and various reports. Since the first state hospital opened in 1851 the statewide inpatient population of individuals who were mentally disabled has grown and peaked at 37,489 in 1959. The number of patients in state hospitals, however, began declining in the early 1960s and was reduced to 10,874 by 1971, and to 4,973 by 1986. As of 1997, there were only 4, 263 inpatients remaining in the state hospital system. This dramatic decrease slowed down somewhat in 1980s and 1990s, but this trend seems irreversible except for the inpatients referred by the court. Now the beds in state hospitals are filled with more and more forensic patients, which constitutes nearly 70% of the total inpatient population. Based on these findings, it is well expected that the number of inpatients of mental hospitals in Korea will also be reduced in a significant way as the community-based mental health care system is gradually replacing the traditional one. Mental hospitals need to introduce more diversified programs for the care of the mentally ill, and concurrently more vigorous aftercare programs are required in the community.

• Journal of Oral Medicine and Pain
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• v.30 no.2
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• pp.201-214
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• 2005

Age estimation is fundamental and important in personal identification with forensic medicine and dentistry. Recently, a lot of studies using various part of the body have been done for age estimation. Age estimation with teeth is the most significant method comparing ones with other part of the body. Gustafson method and Johanson method using postmortem teeth have been authorized in accuracy and systemization and used domestically and internationally. The verification of the accuracy in above methods had been tried many times but it is still rare in Korea. Fifty-nine teeth(incisors, canine, premolars and molars) which were extracted due to periodontal diseases or orthodontic problem were collected. Present study is to 1) compare the accuracy of estimated age in applying Gustafson method and Johanson method to the teeth in Korea, 2) compare and analyze the correlation with results using Gustafson method and Johanson method by age, gender, maxilla - mandible and anterior - premolar - molar. Teeth were embedded in resin and sliced and then examined each one using Gustafson method and Johanson method. The results are as follows: 1. Actual age was a significant difference in estimated age by Johanson method. Actual age was a significant correlation in estimated age by Gustafson method and modified Johanson method. Modified Johanson method was more significant than Gustafson method. 2. In estimated age by Gustafson method, Johanson method and modified Johanson method, there was no significance with actual age by location and gender. 3. In estimated age by Gustafson method, Johanson method and modified Johanson method, there was significance with actual age by age group. Finally, Gustafson method and Johanson method can be used in Korea. To make more accurate verification, however, it needs more specimen and postmortem teeth. Johanson equation proposed by himself has to be developed by further studies.