• 한국통신학회논문지
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• 제32권2B호
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• pp.83-89
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• 2007

본 논문에서는 OLT의 중앙집중 제어에 의한 대역폭 중재 없이 ONU간의 분산적인 동적 대역폭 할당을 이룰 수 있는 파워 검출 기반의 TDM-PON의 MAC 프로토콜을 제안하였다. 기존의 E-PON에서 사용하는 소프트웨어 기반의 DBA 방식과 달리, 제안된 방식은 하드웨어 기반의 파워 검출을 활용하여 동적 대역폭 할당 알고리즘을 수행함으로써 간단하고 빠르며 비용효과 측면에서 장점을 가진다. 제안된 가입자 망의 성능 평가는 수식적 분석과 컴퓨터 시뮬레이션을 통하여 수행하였으며, 특히 다양한 트래픽 모델 환경에서 제안된 방식의 성능향상 정도를 기존 E-PON들과 비교 및 분석하였다.

• Clinical Endoscopy
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• 제56권5호
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• pp.604-612
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• 2023

Background/Aims: We developed a new endoscopic submucosal dissection (ESD) simulator and evaluated its efficacy and realism for use training endoscopists. Methods: An ESD simulator was constructed using polyvinyl alcohol hydrogel sheets and compared to a previous ESD simulator. Between March 1, 2020, and December 30, 2021, eight expert endoscopists from three different centers analyzed the procedure-related factors of the simulator. Five trainees performed gastric ESD exercises under the guidance of these experts. Results: Although the two ESD simulators provided overall favorable outcomes in terms of ESD-related factors, the new simulator had several benefits, including better marking of the target lesion's limits (p<0.001) and overall handling (p<0.001). Trainees tested the usefulness of the new ESD simulator. The complete resection rate improved after 3 ESD training sessions (9 procedures), and the perforation rate decreased after 4 sessions (12 procedures). Conclusions: We have developed a new ESD simulator that can help beginners achieve a high level of technical experience before performing real-time ESD procedures in patients.

• 펄프종이기술
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• 제47권4호
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• pp.38-45
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• 2015

Fold cracking is one of quality troubles of coated papers. In this study, the fold cracking of high grammage ($250g/m^2$) coated paper made with the different pulp composition and layer structure of base paper was investigated. The single layered, high grammage base paper was prepared by mixing of hardwood and softwood bleached kraft pulp fibers with the different ratios. The high grammage coated paper showed the higher fold cracking than low grammage coated paper because of the increase in thickness. The increase in the content of softwood pulp fibers reduced the fold cracking in the case of high grammage coated paper. When the creasing process was conducted before folding process, the fold cracking of coated paper decreased. By manufacturing the base paper with multiply structure, the fold cracking of coated paper could be reduced significantly, especially when the BCTMP and OCC were used as a middle layer and the creasing process was carried out. The delamination of layers in base paper affected the fold cracking positively.

• 한국산업보건학회지
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• 제4권1호
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• pp.117-126
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• 1994

Some of the important and vital roles performed by the Health Care Center of Pohang Iron & Steel Co., Ltd.(POSCO) are the periodic monitoring of the work sites as well as regular medical check-ups for each workers to ensure both pleasant and safe working conditions and to protect employees' health. Pohang Steel Works, which has 42 plants, 26 facilities and 12,000 employees, has an annual crude steel production capacity of 9,670,000 using 24,500,000 ton of raw materials. We have measured lots of areal and personal working environment according to Occupational Safety and Health Law semiannually. All data collected on industrial hygiene is stored and managed by personal computer. The developed of a computerized industrial hygiene control system linked to the company's main computer system will provide efficient evaluation of the working environment as well as critical informations on employees' health. Development of this system had begun in May, 1992 and was completed in March, 1994. The computerized industrial hygiene control system can; 1. store industrial hygiene data, providing key pertinent to the diagnosis of occupational related illnesses, and if necessary, the basis for improving the working environment, 2. decide type and time of medical examination of each work for exposure to specific agents, and supply proper protection periodically, 3. prevent occupational related illnesses through evaluation of environmental and biological monitoring, and performance of epidemiological surveillance, 4. facilitate proper job placement through linking of industrial hygiene control and personnel information systems, 5. monitor job processes. levels of chemical agents used, and new agents introduced, 6. and increase productivity by saving time resulting from the implementation of the computerized sysyte,

• Genomics & Informatics
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• 제8권1호
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• pp.9-18
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• 2010

Integrins are transmembrane receptor proteins that mediate cell-cell adhesion and cell-extracellular matrix (ECM) adhesion. The deregulation of cell-ECM adhesion and the abnormal expression of beta1 (${\beta}1$) integrins (ITGB1s) are involved in tumor development and metastasis. In the liver, the expression of integrins and ECM proteins can be a cause of hepatocellular carcinoma (HCC) development. We performed direct DNA sequencing of 24 individuals, and identified 23 sequence variants of ITGB1 polymorphisms. Among these 23 variants, 7 common variants were selected based on frequencies and linkage disequilibrium, and then genotyped in a larger-scale group of subjects (n=1,103). The genetic associations of ITGB1 polymorphisms with the clearance of HBV and HCC outcome of HBV patients were analyzed using logistic regression models and Cox relative hazard models. Although there was no significant association observed between the polymorphisms and the HCC outcome of HBV patients, the second most common haplotype (ITGB1 haplotype-2 [C-C-C-C-T-C-T]) was putatively associated with HBV clearance (OR=0.75, p=0.008 and $P^{corr}=0.05$). The minor allele frequency (MAF) of ITGB1 haplotype -2 of the spontaneously recovered (SR) group was significantly higher than that of the chronic carrier group (CC) (freq. = 0.248 vs. 0.199). The information derived from this study could be valuable for understanding the genetic factors involved in the clearance of HBV.

• Genomics & Informatics
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• 제8권1호
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• pp.1-8
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• 2010

Serpin peptidase inhibitor, Clade B (ovalbumin), Member 5 (SERPINB5), also known as maspin, is a potent tumor suppressor gene. It has correlations with many tumor cells, from pancreas cancer to breast cancer, so it is possible that it may also affect liver cancer. There has also been a report that SERPINB12, a gene placed right next to SERPINB5, is expressed in liver. For this study, 32 polymorphisms were identified in SERPINB5 by direct DNA sequencing, and 11 of them were selected to be tested with a larger scale subjects. The association of the 11 SERPINB5 polymorphisms with Hepatitis B virus (HBV) clearance, hepatocellular carcinoma (HCC) occurrence and the onset age of HCC were analyzed. There were no significant associations found between 11 SERPINB5 polymorphisms and HBV clearance. In the case of HCC occurrence, one of the haplotypes (ht) showed association with HCC occurrence (OR=2.26, p=0.005, $P^{Cor}=0.05$), albeit with a low statistical power (40.8%) and haplotype frequency (0.052). Further study with a bigger sample size will be needed to clearly verify the association between ht5 and HCC occurrence.

• Journal of Trauma and Injury
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• 제23권2호
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• pp.151-156
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• 2010

Purpose: The liver is the second most common organ injured by blunt abdominal trauma. The purpose of this study was to determine the utility of liver transaminase in screening blunt abdominal trauma patients for traumatic liver injury. Methods: We retrospectively reviewed the medical records of 231 patients who sustained blunt trauma and were at risk for traumatic liver injury between June 2009 and August 2010. All of them underwent a focused assessment with sonography for trauma (FAST) and abdominal computed tomography (CT). Based on the diagnosis of abdominal CT, patients were divided into two groups: group I with liver injury and group II without liver injury. We compared the two groups and calculated the sensitivity, the specificity and the predictive values of serum aspartate aminotransferase (AST) and serum alanine aminotransferase (ALT) by using multiple cutoff values. Results: Of 231 patients with no abdominal free fluid in the FAST, 33 had traumatic liver injury on abdominal CT. The mean AST and ALT levels in group I (311.6 IU/L and 228.1 IU/L, respectively) were significantly higher than the values in group II (48.4 IU/L and 35.6 IU/L, respectively). The cutoff to distinguish liver injury is 60 IU/L for AST and 58 IU/L for ALT, with 93.8% sensitivity and 79.8% specificity for AST, and 90.6% sensitivity and 87.4% specificity for ALT. Conclusion: We recommend that all patient with suspected blunt abdominal trauma be evaluated using serum liver transaminase as a screening test for liver injury even though no abdominal free fluid is shown on the FAST. If AST > 60 IU/L and/or ALT > 58 IU/L, abdominal CT was useful to confirm liver injury in this study.

• Tuberculosis and Respiratory Diseases
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• 제44권6호
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• pp.1419-1425
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• 1997

저지들은 재발된 원발성 종격동 비정상피종과 동반된 Klinefelter 증후군 1예를 경험하였기에 문헌고찰과 함께 보고하는 바이다.

• Genomics & Informatics
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• 제7권4호
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• pp.195-202
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• 2009

BIRC5 (Survivin) belongs to the inhibitor of apoptosis gene family. The BIRC5 protein inhibits caspases and consequently blocks apoptosis. Thus, BIRC5 contributes to the progression of cancer allowing for continued cell proliferation and survival. In this study, we identified eight sequence variants of BIRC5 through direct DNA sequencing. Among the eight single nucleotide polymorphisms (SNPs), six common variants with frequencies higher than 0.05 were selected for larger-scale genotyping (n=1,066). Results of the study did not show any association between the promoter region polymorphisms and the clearance of hepatitis B virus (HBV) infection and hepatocellular carcinoma (HCC) occurrence. This is in line with a previous study in which polymorphisms in the promoter region does not influence the function of BIRC5. Initially, we were able to detect a signal with the ＋9194A>G, which disappeared after multiple corrections but led to a change in amino acid. Similarly, we were also able to detect an association signal between two haplotypes (haplotype-2 and haplotype-5) on the onset age of HCC and/or HCC occurrence, but the signals also disappeared after multiple corrections. As a result, we concluded that there was no association between BIRC5 polymorphisms and the clearance HBV infection and/or HCC occurrence. However, our results might useful to future studies.

• Genomics & Informatics
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• 제7권4호
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• pp.187-194
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• 2009

Cytochrome P450 2E1 (CYP2E1) is a member of the cytochrome P450 superfamily, and it is a key enzyme responsible for the metabolic activation of many smallmolecular-weight compounds such as alcohol, which is classified as a human carcinogen. In this study, we identified 19 single nucleotide polymorphisms (SNPs) in CYP2E1 in Korean population. In these SNPs, we examined possible genetic association of CYP2E1 polymorphisms with HBV clearance and the risk of hepatocellular carcinoma (HCC). Five common polymorphic sites were selected, CYP2E1 polymorphisms at rs381-3867, rs3813870, rs2070673, rs2515641 and rs2480257, considering their allele frequencies, haplotype-tagging status and LDs for genotyping in larger-scale subjects (n=1,092). Statistical analysis demonstrated that CYP2E1 polymorphisms and haplotypes show no significant association with HBV clearance, HCC occurrence and onset age of HCC (p>0.05). Previous studies, however, have shown contradictory findings on associations of CYP2E1 polymorphisms with CYP2E1 activities and HCC risk. Comparing the contrasting results of previous researches suggest that CYP2E1 polymorphism is associated with CYP2E1 activity induced by ethanol, but is not directly associated with HCC risk. CYP2E1 variation/haploype information identified in this study will provide valuable information for future studies on CYP2E1.