• 대한소아치과학회지
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• 제26권1호
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• pp.119-125
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• 1999

Air turbine handpiece를 사용하여 치간 법랑질을 삭제하는 Air-rotor stripping 술식은 악궁확장이나 발치 술식에 대한 대체방안으로써 arch length discrepancy를 해결할 수 있는 효과적인 접근법으로 사료된다.

• Journal of Advanced Research in Ocean Engineering
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• 제2권4호
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• pp.169-178
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• 2016

Recently, artificial reefs (ARs) have been frequently used primarily owing to the development in AR materials and projects for relatively complicated, large ARs. Among several engineering issues of ARs, wake region of an AR has been characterized because these regions have a high probability of recruiting seaweed spores, providing an energy saving zone, and facilitating deposition of sediments, nutrients, and bio-deposits. To characterize an efficiency index of an AR wake region and its dependency on the prevailing water flow directions, this study proposes a so-called efficiency index diagram. This characterization is done by normalizing the wake volumes with respect to the real AR volume and illustrating how efficiency indices vary with respect to the inlet flow directions. As a result, according to the diagram characteristics such as an averaged efficiency index, fundamental symmetric angle, secure angles, and principal directions, we can easily figure out how a target AR should be aligned along the main water flows to maximize the wake region around the AR. In addition, six ARs are considered and their efficiency index diagrams are illustrated to pinpoint the physical characteristics.

• Clinical and Experimental Pediatrics
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• 제59권1호
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• pp.35-39
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• 2016

Purpose: This study compared the efficacy and tolerability of intravenous (i.v.) phenobarbital (PHB) and i.v. levetiracetam (LEV) in children with status epilepticus (SE) or acute repetitive seizure (ARS). Methods: The medical records of children (age range, 1 month to 15 years) treated with i.v. PHB or LEV for SE or ARS at our single tertiary center were retrospectively reviewed. Seizure termination was defined as seizure cessation within 30 minutes of infusion completion and no recurrence within 24 hours. Information on the demographic variables, electroencephalography and magnetic resonance imaging findings, previous antiepileptic medications, and adverse events after drug infusion was obtained. Results: The records of 88 patients with SE or ARS (median age, 18 months; 50 treated with PHB and 38 with LEV) were reviewed. The median initial dose of i.v. PHB was 20 mg/kg (range, 10-20 mg/kg) and that of i.v. LEV was 30 mg/kg (range, 20-30 mg/kg). Seizure termination occurred in 57.9% of patients treated with i.v. LEV (22 of 38) and 74.0% treated with i.v. PHB (37 of 50) (P=0.111). The factor associated with seizure termination was the type of event (SE vs. ARS) in each group. Adverse effects were reported in 13.2% of patients treated with i.v. LEV (5 of 38; n=4, aggressive behavior and n=1, vomiting), and 28.0% of patients treated with i.v. PHB (14 of 50). Conclusion: Intravenous LEV was efficacious and safe in children with ARS or SE. Further evaluation is needed to determine the most effective and best-tolerated loading dose of i.v. LEV.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 A
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• pp.412-414
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• 1994

A new active resonant snubber (ARS) circuit providing the ideal switching conditions for PWM converter is presented. By using the proposed ARS circuit to PWM converters, the power switches can be operated to give zero-current and zero-voltage at both the instant of switch off and switch on, without increasing voltage/current stresses of the switches. Furthermore, the PWM converters employed ARS circuit has the advantage that it can operate at constant frequency, giving better definded EMI and filter ripple, and it is also suited for high-power application regardless of the semiconductor devices (such as MOSFETs or IGBTs) used as a power switches.

• BMB Reports
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• 제32권6호
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• pp.547-553
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• 1999

Aminoacyl-tRNA synthetases are essential enzymes catalyzing the attachment of specific amino acids to cognate tRNAs. In the present work, the substrate analogue L-methionine hydroxamate was used to identify functional residues located in the active site of the E. coli methionyl-tRNA synthetase (MetRS). This compound inhibited bacteria, yeast, and human MetRS activities to a similar degree, suggesting a conserved active site structure and mechanism between MetRSs of different phylogenetic domains. Mutants of the E. coli MetRS resistant to methionine hydroxamate were also isolated. These mutants contained a substitution either at T10, Y15, or Y94. These residues are highly conserved among the different MetRSs and the mutants showed decreased aminoacylation activity, suggesting their functional and structural significances. The putative roles of these residues are discussed on a structural basis.

• Environmental Engineering Research
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• 제15권1호
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• pp.15-21
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• 2010

This study was conducted to evaluated seawater bacteria and their seasonal characteristics in the arsenic contaminated coastal seawater of Yeosu Bay, the Republic of Korea. Arsenite-oxidizing bacteria play an important role in the seawater of the arsenic contaminated bay, with a variety of arsenic resistance system (ars) genotypes being present during summer. Specifically, Bacillus sp. strain SeaH-As22w (FJ607342), isolated from the bay, were found to contain the arsB, arrA and aoxR type operons, which are involved in arsenic resistance. The isolated bacteria showed relatively high tolerance to sodium arsenite (III; $NaAsO_2$) at concentrations as high as 50 mM. Additionally, batch seawater experiments showed that Bacillus sp. strain SeaH-As22w completely oxidized 1 mM of As (III) to As (V) within 10 days. Ecologically, the arsenic-oxidizing potential plays an important role in arsenic toxicity and mobility in As-contaminated coastal seawater of Yeosu Bay during all seasons because it facilitates the activity of Bacillus sp. groups.

• Journal of the Korean Data and Information Science Society
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• 제26권3호
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• pp.593-610
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• 2015

적응 기각 추출 (adaptive rejection sampling)방법은 특정한 형태의 확률분포로 부터 확률표본을 추출하기 위한 대표적인 난수생성기 (random number generator)로서, 추출된 표본으로부터 제안분포 (proposal distribution)가 개선이 되는 장점을 가지고 있다. 그러나, 기존에 제안된 적응기각추출 방법은 확률분포의 형태가 로그-오목 함수 (log-concave function)인 경우에만 사용이 가능하기 때문에 적용범위가 제한적이다. 최근의 연구결과에서는, 이러한 단점을 보완하기 위해 다양한 형태의 적응기각추출이 진행되고 있으며, 이에 본 논문에서는 기존의 적응기각추출 방법을 포함한 총 5가지의 난수 생성 방법에 대해서 고찰하고, 아울러 모의실험을 통해 각 방법들간의 성능에 대하여, 적합성과 효율성의 관점에서 실증적으로 비교 분석하도록 한다.

• Tuberculosis and Respiratory Diseases
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• 제83권4호
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• pp.268-275
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• 2020

Background: It is not evident that the attributable risk of smoking on mortality in Korea has decreased. We investigated the impact of smoking on all-cause mortality and estimated the attributable risk of smoking in Korean adults. Methods: Those aged ≥20 years with smoking history in the Korean National Health and Nutrition Examination Surveys (KNHANES) 2007-2015 were enrolled. We categorized the participants into three groups as follows: never smoker, <20 pack-years (PY) smokers, and ≥20 PY smokers. We applied inverse probability weighting using propensity scores to control various confounders between the groups. All-cause mortality risks were compared between the groups using the Kaplan-Meier log-rank test. The effects of smoking-attributable risks (ARs) on mortality were also calculated. Results: A total of 50,458 participants were included. Among them, 19,334 (38.3%) were smokers and 31,124 (61.7%) were never smokers. Those with a smoking history of 20 PY or more (≥20 PY smokers), those with a smoking history of less than 20 PY (<20 PY smokers), and never smokers were 18.1%, 20.2%, and 61.7%, respectively, of the study population. Smokers had a higher risk of all-cause mortality compared to never smokers (log-rank test p<0.01). The ARs of smoking were 21.8% (95% confidence interval [CI], 5.7%-37.9%) and 9.0% (95% CI, 6.1%-12.0%) in males and females, respectively. ARs decreased from 24.2% to 19.5% in males and from 9.5% to 4.1% in females between 2007-2010 and 2011-2015. Conclusion: Our study using KNHANES IV-VI data demonstrated that smoking increased the risk of all-cause mortality in a dose-response manner and the ARs of smoking on mortality were 21.8% in males and 9.0% in females during 2007-2015. This suggests that the ARs of smoking on mortality have decreased since around 2010.

• Journal of Microbiology
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• 제35권2호
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• pp.92-96
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• 1997

A new site-specific recombinase sin, as a component of a putatie transposon has been cloned and its base sequence has been determined. The proposed sin shows a hish degree of homology with pI9789-sin and pSK1-sin. There is a large (16 bp) inverted repeat downstream of proposed sin and the postulate dhelix-turn-helix motif is located at the extreme C-terminus of the poposed Sin. The transposase gene (tnpA) and .betha.-lactamase gene (blaZ) are located upstream of sin and arsenate reductase gene (arsC) and arsenic efflux pump protein gene (ars B) are downstream. This genetic arrangement seems to be a part of a new putative transposon because there is no known transposon with a gene arrangement of tnpA-blaZ-sin-arsC.

• 한국해양환경ㆍ에너지학회지
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• 제12권3호
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• pp.181-187
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• 2009

본 연구에서는 인위적인 어장 조성을 위해 해저에 시설된 사각형어초의 현존 상태 및 수량을 평가하고자 Multi-Beam Echo Sounder(MBES)와 Side Scan Sonar(SSS) 등의 조사에서 생산된 자료를 사용하여 단위어초의 부피, 산적 어초의 체적 및 공극률을 계산하고 이를 잠수조사 결과와 비교함으로써 단위어초(사각형 어초)의 현존 시설량 산정공식의 효율성을 검토하였다. 부산연안에 시설되어 있던 총 9곳의 사각형어초로 조성된 단위어초의 평균 유효공용적율 k값은 0.753이었으며 k값과 시설경과년수(year,Yr)와의 상관식은 k=0.0023Yr+0.725로 추정되었으나 그 상관성은 매우 낮은 것으로 나타났다. 따라서 인공어초 설치후 시간이 경과할 수 록 산적되어진 어초의 침하 또는 간극의 축소로 인해 다짐의 정도가 커지는 효과가 발생함에도 불구하고 어초의 시설 경과 연도와 k값과의 상관성은 낮았으며 이에 반해 해역의 저질 조건 및 초기 시설 당시의 설치조건에 따라서 k값이 달라 질수 있음을 알 수 있었다.