• Journal of Periodontal and Implant Science
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• 제49권1호
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• pp.2-13
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• 2019

Purpose: The aim of this study was to conduct a histologic evaluation of irradiated calvarial defects in rats 4 weeks after applying fibroblast growth factor-2 (FGF-2) with hyaluronan or biphasic calcium phosphate (BCP) block in the presence or absence of adjunctive hyperbaric oxygen (HBO) therapy. Methods: Twenty rats were divided into HBO and non-HBO (NHBO) groups, each of which was divided into FGF-2 and BCP-block subgroups according to the grafted material. Localized radiation with a single 12-Gy dose was applied to the calvaria of rats to simulate radiotherapy. Four weeks after applying this radiation, 2 symmetrical circular defects with a diameter of 6 mm were created in the parietal bones of each animal. The right-side defect was filled with the materials mentioned above and the left-side defect was not filled (as a control). All defects were covered with a resorbable barrier membrane. During 4 weeks of healing, 1 hour of HBO therapy was applied to the rats in the HBO groups 5 times a week. The rats were then killed, and the calvarial specimens were harvested for radiographic and histologic analyses. Results: New bone formation was greatest in the FGF-2 subgroup, and improvement was not found in the BCP subgroup. HBO seemed to have a minimal effect on new bone formation. There was tendency for more angiogenesis in the HBO groups than the NHBO groups, but the group with HBO and FGF-2 did not show significantly better outcomes than the HBO-only group or the NHBO group with FGF-2. Conclusions: HBO exerted beneficial effects on angiogenesis in calvarial defects of irradiated rats over a 4-week healing period, but it appeared to have minimal effects on bone regeneration. FGF-2 seemed to enhance new bone formation and angiogenesis, but its efficacy appeared to be reduced when HBO was applied.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제9권2호
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• pp.39-44
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• 2020

본 논문에서는 사전연산이 가능한 세션 키 쌍을 이용하여, 최소의 정보만을 노출하여 키 교환이 가능한 변형된 Diffie-Hellman 키 교환 프로토콜을 보인다. 기존 Diffie-Hellman 및 Diffie-Hellman 기반 기법들의 보안성인 이산대수문제를 변형하여 생성원이 노출되지 않도록 설계함으로써 전송되는 암호문에 대한 공격으로부터 향상된 보안성을 가진다. 제안하는 기법에 실제 값을 적용하여 알고리즘의 동작을 증명하고 기반이 되는 기존 알고리즘과의 수행시간과 안전성을 비교 분석하여, 키 교환 시점 연산량을 유지하며 두 기반 알고리즘 시간복잡도의 곱 이상으로 알고리즘의 안전성이 향상되었음을 보였다. 제안하는 알고리즘을 기반으로 보안성이 향상된 키 교환 환경을 제공할 수 있을 것으로 기대된다.

• Journal of Gastric Cancer
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• 제19권4호
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• pp.451-459
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• 2019

Purpose: Laparoscopic surgery is associated with lower surgical site infection (SSI) rates due to minimal skin incision and non-exposure of visceral organs. Most previous studies have analyzed the efficacy of prophylactic antibiotic use in open surgery. Here, we investigated the feasibility of total laparoscopic distal gastrectomy (TLDG) for gastric carcinoma without prophylactic antibiotic use. Materials and Methods: Seventy-one patients who underwent TLDG without prophylactic antibiotic use were 1:1 propensity score matched with 393 patients who underwent TLDG with antibiotic prophylaxis. The short-term surgical outcomes, including SSI rates, were compared between the groups. Results: After matching, 65 patients were selected in each group. The baseline clinicopathological characteristics were well balanced in the matched sample. In the matched group, there was no significant increase in postoperative morbidity in the non-prophylactic group compared with the prophylactic group (18.5% vs. 15.4%, P=0.640), and there were no grade 3≤ complications (1.4% vs. 0%, respectively; P=1.000). The SSI rates in the non-prophylactic and prophylactic groups were 3.1% and 1.5%, respectively (P=0.559). The time to gas passage, diet initiation, and mean hospital stay were not significantly different between the 2 groups. The SSI rate did not increase in the non-prophylactic group in the different subgroups based on different clinicopathological characteristics. Conclusions: Postoperative morbidity, including SSI rates, did not significantly increase in patients undergoing TLDG without prophylactic antibiotic use. A large prospective randomized trial is warranted to reappraise the efficacy of prophylactic antibiotic use in patients undergoing TLDG.

• Clinical Endoscopy
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• 제56권5호
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• pp.633-649
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• 2023

Background/Aims: Mechanical properties (MPs) and axial and radial force (AF and RF) may influence the efficacy and complications of self-expandable metallic stent (SEMS) placement. We measured the MPs of various SEMSs and examined their influence on the SEMS clinical ability. Methods: We evaluated the MPs of 29 types of 10-mm SEMSs. RF was measured using a conventional measurement device. AF was measured using the conventional and new methods, and the correlation between the methods was evaluated. Results: A high correlation in AFs was observed, as measured by the new and conventional manual methods. AF and RF scatterplots divided the SEMSs into three subgroups according to structure: hook-and-cross-type (low AF and RF), cross-type (high AF and low RF), and laser-cut-type (intermediate AF and high RF). The hook-and-cross-type had the largest axial force zero border (>20°), followed by the laser-cut and cross types. Conclusions: MPs were related to stent structure. Hook-and-cross-type SEMSs had a low AF and high axial force zero border and were considered safest because they caused minimal stress on the biliary wall. However, the increase in RF must be overcome.

• Animal Systematics, Evolution and Diversity
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• 제15권2호
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• pp.153-164
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• 1999

한국, 중국, 러시아에 서식하는 등줄쥐 Apodemus agrarius 6아종 111마리를 이용하여, 미토콘드리아 DNA를 8개의 제한효소로 절단한 단편들을 blot hybridization법으로 분석하였다. 모두 32개의 단편들이 보여졌고, 9개의 haplotype이 밝혀졌으며, 평균 발산값이 0.896에서 1.150%인 4아군이 나타났다. 결론적으로 세 형을 인정할 수가 있었다: [I. 아종 chejuensis (제주도, 한국)], [ll, 아종 pallescens(남서 한국), coreae(중앙 한국), 및 septentrionalis(러시아)], and [lll, 아종 manchuricus(북동 중국)와 pallidior(북부 중국)]. 그러나 아종 coreae의 일부 표본들은 다른 6아종의 표본들과 다소 차이를 보였고, 아종 pallidior의 일부 표본들은 아종 septentrionalis의 모든 표본들과 같아서 동일한 haplotype을 형성하였다. 아종 a. agrarius chejuensis는 독특한 아종중의 하나이고, 아종 corea(pallescens포함)도 독특한 아종중의 하나이며, 아종 manch-uricus와 pallidior는 아종 ningpoensis의 동아종이명이고, 아종 septentrionalis도 아종 agrarius의 동아종이명임이 재확인되었다. 뿐만 아니라, 등줄쥐는 염색체 핵형이 일정하며, 미토콘드리아 DNA 유전형에 약간의 변이를 보이고, 형태형질의 상당한 발산을 보이고 있지만, 이들 분류형질의 변이 정도의 파악과 아종분류의 재검토를 위하여 유라시아산 등줄주의 보다 많은 표본을 이용한 분석이 앞으로 필요하다.