Counter Clinical Prognoses of Patients With Bloodstream Infections Between Causative Acinetobacter baumannii Clones ST191 and ST451 Belonging to the International Clonal Lineage II

This study was conducted to evaluate the possible clinical and bacteriologic features associated with 30-day mortality from Acinetobacter baumannii (A. baumannii) bloodstream infections (BSIs). We conducted a prospective, multicenter, observational study of 181 entire episodes of A. baumannii BSI from six general hospitals between May 2016 and April 2017 in South Korea. Cox proportional-hazards regression model was used to estimate risks of the primary endpoint, i.e., all-cause mortality within 30 days from the initial blood culture. Most (84.5%) of the A. baumannii blood isolates belonged to the international clonal lineage II (ICLII) and 89.5% of the isolates were either multidrug- or extensively-drug resistant. We identified three risk factors including the old age of patient {hazard ratio, 1.033; [95% Confidential Interval (CI), 1.010-1.056]}, the sequential organ failure assessment score [1.133 (1.041-1.233)], and causative A. baumannii sequence type (ST) 191 belonging to ICLII [1.918 (1.073-3.430)], and three protective factors including causative A. baumannii ST451 belonging to ICLII [0.228 (0.078-0.672)], platelet count [0.996 (0.993-0.999)], and definitive therapy within 72 h [0.255 (0.125-0.519)]. Differing 30-day mortality rate in the dominant ICLII was observed by ST, which was much high in ST191 and low in ST451 and it was likely associated with the molecular traits, rather than the drug resistance.ope

국내에서 분리된 인체분리균주를 이용한 MicroScan KSCM 패널의 항균제 감수성 시험 분석능 평가

Background: Antimicrobial resistant continues to pose a threat to public health. Therefore, rapid and accurate antimicrobial susceptibility testing is very important. The objectives of this study were to evaluate the performance of the MicroScan system (Beckman Coulter, USA) with newly developed Korean Antimicrobial Susceptibility Testing Panels (KSCM panels) for antimicrobial susceptibility testing (AST) against clinical isolates in South Korea. Methods: Three KSCM panels were designed in this study. For the performance evaluation, a total of 1,325 clinical isolates including 1,027 of Gram-negative bacilli and 298 Gram-positive cocci collected from eight general hospitals in South Korea were used. The results by KSCM panels were compared with those by conventional methods. Results: By KSCM-1 panel for Gram-positive cocci, the rates of categorical agreement (CA) were ＞90% in all the antimicrobials tested in this study. The rates of major error (ME) were also ＜3%, and only three very major error (VME) were identified; each of ampicillin, tetracycline, and quinupristin-dalfopristin in enterococcal isolates. By KSCM-2 panel for Enterobacteriaceae, the rates of CA were also above 90%, and those of ME and VME were less than 3% and 1.5%, respectively. KSCM-3 panels for glucose- non-fermenting Gram-negative bacilli, also showed good agreement rates, i.e., CA rates ＞90%, ME rates ＜3%, and VME rates ＜1.5%. Conclusion: The newly developed three KSCM panels for MicroScan system (Beckman Coulter) showed excellent performance in AST against a large number of clinical isolates, and they are applicable to clinical microbiology laboratories.ope

A Study on Applicability of Production Optimization on Offshore Oil Field using Integrated Production Modeling

Oil industry has been extremely matured during last decades. It becomes very hard to discover new giant fields even with deep sea drilling and exploration works. Therefore, it is essential to manage discovered field efficiently. With making integrated decision-making system of field management, well and reservoir surveillance data are utilized to explain performances of sub-surface and surface facility systems. Especially, Integrated Production Modeling(IPM) is commonly used to describe pressure interaction between reservoir and surface facilities, and its efficiency has been proved through several field cases. In this study, IPM is suggested for Captain filed, located in the United Kingdom sector of North Sea, with various operating conditions of injection water, power water, produced water handling volumes, FPSO's off loading capacity, etc. It comprises with coupling of 5 material balance models, 25 production well models, 10 water injection well models, and one surface facility model. By comparison with the measured data, the model forecasts show reliable results with 7% and 5% discrepancy in production well and injection well performances, respectively.제 1 장 서론 1 제 2 장 통합생산모델 관련 연구동향 3 2.1 개요 3 2.2 저류층 시뮬레이션을 이용한 통합생산모델 4 2.3 물질평형 모델을 이용한 통합생산모델 16 제 3 장 물질평형 모델을 이용한 통합생산모델 구축 23 3.1 개요 23 3.2 적용대상 23 3.3 물질평형 모델 구축 27 3.4 물질평형 모델 적용 32 3.5 유정 모델 및 지표설비 모델 구축 41 3.6 통합 모델 구축 및 예측거동 분석 46 제 4 장 통합생산모델을 통한 생산최적화 적용 가능성 50 4.1 통합생산모델을 통한 생산최적화 개요 50 4.2 통합생산모델을 통한 캡틴 유전 생산최적화 적용 가능성 53 제 5 장 결론 55 참고문헌 57 참고서적 6

Performance Evaluation of the Newly Developed In Vitro Rapid Diagnostic Test for Detecting OXA-48-Like, KPC-, NDM-, VIM- and IMP-Type Carbapenemases: The RESIST-5 O.K.N.V.I. Multiplex Lateral Flow Assay

The objective of this study was to evaluate the performance of the RESIST-5 O.K.N.V.I. assay for identifying these five common domestic carbapenemases among a large number of clinical isolates in South Korea. A total of 268 non-duplicated clinical isolates of gram-negative bacilli were included in this study as follows: 258 carbapenemase-producing (CP) strains (OXA-48-like, KPC, NDM, VIM, IMP, GES, OXA-23 and two or more carbapenemase producers) and 10 non-CP carbapenem-resistant Enterobacterales (non-CP CREs). Overall sensitivity and specificity were 98.4% and 100%, respectively. In addition, all non-targeted carbapenemase producers including GES and OXA-23 producers and non-CP CREs were correctly identified as negative results. There were only four discrepant cases in which three VIM carbapenemase producers and one NDM carbapenemase producer were not detected. The RESIST-5 O.K.N.V.I. assay as an in vitro diagnostic test for detecting five common carbapenemases provided rapid and accurate results in a short time, indicating that this method could provide an innovative solution for early detection, resulting in appropriate antimicrobial treatment in the clinical field.ope

『서울대학교 法學』 50년을 되돌아보며 : 법철학 분야

서울대학교 법과대학이 자랑할 만한 점들 중 하나는 기초법 분야의 교수진이 다양하다는 것이고, 그 연구 관심사가 깊고도 넓으며 수준 또한 당대 국내 최고 라는 것이다. 이러한 특성은 법학지에 게재된 논문들에 반영되어 언제나 연구 지평을 새로이 넓혔으며, 기존의 연구 내용을 이론적으로 발전시키는 데 큰 기여를 했다. 법철학 분야로 좁혀서 보더라도 마찬가지이다. 아래에서는 『서울대학교 法學』 50년 동안 법철학 관련 논문들의 주제, 연구내용, 학문적 성과, 학술적 기여도를 살펴보고, 『서울대학교 法學』에 게재되었던 연구의 흐름을 일별하면서 앞으로 나아갈 때 길잡이로 삼고자 한다

Advanced Core Design of Soluble Boron Free Small Modular Reactor for Marine Applications

학위논문 (석사) -- 서울대학교 대학원 : 공과대학 에너지시스템공학부, 2021. 2. 심형진.There are many studies about marine floating small modular reactor (SMR) for ship propulsion, power supply to remote locations, and seawater desalination. The SMR design is considering applying the soluble boron-free operation, which can simplify the system and improve operability. Recently, KEPCO E&C is developing Bandi-60, the SMR with thermal power of 200 MW, and in this study, the optimal core of soluble boron-free SMR is designed for this purpose. As a result of the previous study, the core with thermal power of 200MW and a cycle length of 5 years was designed using UO2 fuel material with enrichment of 4.95 w/o loaded with a total of 52 fuel assemblies. However, it is required to design the SMR, considering the condition of a thermal-hydraulic feedback effect and the soluble boron free operation. The purpose of this study is to confirm whether the previous core satisfies the design requirements when considering a thermal-hydraulic feedback effect and to design the optimal core. The burn-up calculation of the optimum core is performed under critical-state conditions using a control rod in soluble boron-free conditions. The core characteristics are calculated by the results of the burn-up calculation under critical-state conditions. In this paper, core design requirements are selected to be 4 to 5 years of cycle length, excess reactivity of less than 5,000, and minimizing peaking factor. In addition, the purpose is to design a reactivity control system that can provide sufficient negative reactivity in cold zero power (CZP). The fuel assembly (FA) is based on the Westinghouse 17⨯17 FA, and 52 FAs are loaded in the core. The fuel material is UO2 with an enrichment of 4.95 w/o. Pyrex is used as burnable absorber (BA) for reactivity control. The core is composed of a combination of 5 types of FA with different concentrations of B2O3 in Pyrex. Monte Carlo Code for Advanced Reactor Design (McCARD), a Monte Carlo particle transport analysis code developed by Seoul National University, is used for the core design of SMR. The SMR meeting the design criteria is designed by McCARD burn-up calculation with T/H feedback. The core has enough control rod to maintain subcritical-state below the effective multiplication factor (keff.) of 0.95 at cold zero power in the beginning of the cycle (BOC). The estimated cycle length is 4.92 ± 0.23 years, the maximum excess reactivity after equilibrium Xenon is 2,366 ± 12 pcm, the maximum Fq is 2.29±0.10, and the maximum linear power density is 16.67±0.73 kW/m, which meets the design requirements. In addition, by performing the McCARD burn-up calculation maintaining the reactor criticality, this study shows that the SMR can operate up to about 4.79 years in soluble boron-free conditions. During the entire core lifetime, the maximum Fq is 3.09±0.23, and the maximum linear power density is 22.57±1.56 kW/m, which meets the design parameters with sufficient thermal stability. Various nuclear characteristic factors such as the core dynamic characteristics, the reactivity coefficients, and the temperature profiles required for safety analysis and system design of the core are calculated. This study shows that the core has a sufficient reactivity control system to ensure the shutdown margin and operate in soluble boron-free conditions. Therefore, it proposes the advanced core design of soluble boron-free SMR for marine applications.해양부유식 소형모듈형원자로(SMR : Small Modular Reactor)는 선박 추진용, 원격지 전력생산 및 공급, 해수 담수화 등의 목적으로 연구개발이 진행되고 있으며, 계통의 단순화와 운전성 향상을 위해 무붕산 운전 기술 적용을 고려하고 있다. 최근 한국전력기술(주)은 열출력 200MWt의 해양부유식 SMR인 Bandi-60을 개발 중이며, 본 연구에서는 이를 위한 무붕산 SMR 최적노심을 설계하였다. 선행연구에서 농축도 4.95 w/o의 UO 핵연료를 장전한 열출력 200MWt, 주기길이 5년의 예비노심을 설계하였으나, 실제 무붕산 운전 SMR 노심의 운전조건을 고려한 최적노심 개발의 필요성이 제기되었다. 이에, 본 연구는 개념 설계된 예비노심이 열수력 궤환 효과를 고려하였을 때 요구하는 상위요건을 만족하는지 확인하고 기준이 되는 최적노심 설계를 개발하는 것이 목적이며, 개발된 최적노심에 대하여 실제 무붕산 운전조건에서 제어봉 만을 사용하여 원자로 임계를 유지할 수 있는지 확인한 후 원자로 안전해석 및 계통설계에 필요한 노심특성 계산을 수행하였다. 본 연구에서 개발하여야 하는 최적노심의 기준은 주기길이 4~5년, 잉여반응도 5,000pcm 이하에 첨두출력계수를 최소화하고 저온정지조건에서 제어봉만으로도 충분한 정지여유도를 제공할 수 있는 반응도 제어설비를 갖추어야 한다. 따라서, 총 52개의 웨스팅하우스사 형의 17×17 핵연료집합체를 사용하며, 잉여반응도 제어를 위해 각 핵연료집합체에 24개의 Pyrex 가연성흡수봉을 사용하되 Pyrex의 B2O3 함유량을 달리하는 총 5종의 핵연료집합체로 노심을 구성하였다. 노심설계를 위하여 서울대학교에서 개발한 몬테칼로 입자수송해석 코드인 McCARD(Monte Carlo Code for Advanced Reactor Design)를 이용하였으며, McCARD 코드로 열수력 궤환 효과를 고려하여 설계요건을 만족하는 최적노심을 개발하였다. 개발된 노심이 주기초 저온영출력 조건에서의 제한치인 유효증배계수 < 0.95를 만족하며 미임계가 가능하도록 반응도 제어설비를 최적화하였고, 주기길이는 4.92±0.23년, 제논평형 이후 최대 잉여반응도는 2,366±12pcm, 최대첨두출력계수(Fq)는 2.29±0.10, 최대선출력밀도는 16.67±0.73kW/m로 설계요건을 모두 만족하였다. 또한, 실제 무붕산 운전 조건인 제어봉만을 사용하여 원자로 임계를 유지한 연소계산을 수행하여 약 4.79년까지 출력 운전이 가능한 것을 확인하였다. 전 운전주기 동안 최대첨두출력계수(Fq)는 3.09±0.23, 최대선출력밀도는 22.54±1.56kW/m로 제한치(41.38kW/m) 대비 충분한 여유도가 있음을 확인하였으며, 최적노심의 안전해석 및 계통설계에 필요한 노심의 동특성인자, 반응도계수, 온도분포 등 각종 핵특성인자를 계산하였다. 따라서, 반응도 제어설비가 임계운전 능력과 충분한 정지여유도를 제공하여 원자로의 운전성 및 안전성을 보장할 수 있음을 확인함으로써 해양부유식 무붕산 SMR 노심설계 고도화를 달성하였다. 아울러 몬테칼로 노심 설계코드에 열수력 궤환 효과를 고려한 전 주기동안의 제어봉 임계운전을 모의하는 노심설계 방법론을 무붕산 노심핵설계에 적용함으로써 향후 개발될 원자로의 노심설계에 활용될 수 있을 것으로 판단된다.제 1 장 서 론 1 제 1 절 연구배경 및 목적 1 제 2 절 연구범위 2 제 3 절 연구의 구성 3 제 2 장 해양부유식 무붕산 SMR 노심설계 사양 4 제 1 절 해양부유식 무붕산 SMR 노심의 기본 설계요건 4 제 2 절 해양부유식 SMR 노심 잉여반응도 제어 요건 7 제 3 장 해양부유식 무붕산 SMR 노심배치 최적화 14 제 1 절 기존노심 특성 계산 및 분석 14 제 2 절 노심배치 및 반응도 제어설비 설계 최적화 32 제 4 장 열수력 궤환효과를 고려한 최적노심 연소계산 41 제 1 절 임계도 계산 41 제 2 절 출력분포 계산 43 제 5 장 원자로 임계운전모의 연소계산 50 제 1 절 임계도 계산 52 제 2 절 원자로 임계 제어봉 위치 계산 53 제 6 장 원자로 노심특성 계산 및 분석 55 제 1 절 첨두출력계수 계산 55 제 2 절 출력분포 계산 60 제 3 절 온도분포 계산 74 제 4 절 제어봉 제어능 계산 83 제 5 절 반응도계수 계산 85 제 6 절 동특성인자 계산 89 제 7 절 제논 반응도 계산 90 제 7 장 종합 및 결론 91 제 1 절 종 합 91 제 2 절 결 론 93 참 고 문 헌 95 Abstract 97Maste

Nationwide Surveillance of Antifungal Resistance of Candida Bloodstream Isolates in South Korean Hospitals: Two Year Report from Kor-GLASS

We incorporated nationwide Candida antifungal surveillance into the Korea Global Antimicrobial Resistance Surveillance System (Kor-GLASS) for bacterial pathogens. We prospectively collected and analyzed complete non-duplicate blood isolates and information from nine sentinel hospitals during 2020-2021, based on GLASS early implementation protocol for the inclusion of Candida species. Candida species ranked fourth among 10,758 target blood pathogens and second among 4050 hospital-origin blood pathogens. Among 766 Candida blood isolates, 87.6% were of hospital origin, and 41.3% occurred in intensive care unit patients. Adults &gt; 60 years of age accounted for 75.7% of cases. Based on species-specific clinical breakpoints, non-susceptibility to fluconazole, voriconazole, caspofungin, micafungin, and anidulafungin was found in 21.1% (154/729), 4.0% (24/596), 0.1% (1/741), 0.0% (0/741), and 0.1% (1/741) of the isolates, respectively. Fluconazole resistance was determined in 0% (0/348), 2.2% (3/135, 1 Erg11 mutant), 5.3% (7/133, 6 Pdr1 mutants), and 5.6% (6/108, 4 Erg11 and 1 Cdr1 mutants) of C. albicans, C. tropicalis, C. glabrata, and C. parapsilosis isolates, respectively. An echinocandin-resistant C. glabrata isolate harbored an F659Y mutation in Fks2p. The inclusion of Candida species in the Kor-GLASS system generated well-curated surveillance data and may encourage global Candida surveillance efforts using a harmonized GLASS system.ope

Major Bloodstream Infection-Causing Bacterial Pathogens and Their Antimicrobial Resistance in South Korea, 2017-2019: Phase I Report From Kor-GLASS

To monitor national antimicrobial resistance (AMR), the Korea Global AMR Surveillance System (Kor-GLASS) was established. This study analyzed bloodstream infection (BSI) cases from Kor-GLASS phase I from January 2017 to December 2019. Nine non-duplicated Kor-GLASS target pathogens, including Staphylococcus aureus, Enterococcus faecalis, Enterococcus faecium, Streptococcus pneumoniae, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter spp., and Salmonella spp., were isolated from blood specimens from eight sentinel hospitals. Antimicrobial susceptibility testing, AMR genotyping, and strain typing were carried out. Among the 20,041 BSI cases, 15,171 cases were caused by one of the target pathogens, and 12,578 blood isolates were collected for the study. Half (1,059/2,134) of S. aureus isolates were resistant to cefoxitin, and 38.1% (333/873) of E. faecium isolates were resistant to vancomycin. Beta-lactamase-non-producing ampicillin-resistant and penicillin-resistant E. faecalis isolates by disk diffusion method were identified, but the isolates were confirmed as ampicillin-susceptible by broth microdilution method. Among E. coli, an increasing number of isolates carried the bla CTX-M-27 gene, and the ertapenem resistance in 1.4% (30/2,110) of K. pneumoniae isolates was mostly (23/30) conferred by K. pneumoniae carbapenemases. A quarter (108/488) of P. aeruginosa isolates were resistant to meropenem, and 30.5% (33/108) of those carried acquired carbapenemase genes. Over 90% (542/599) of A. baumannii isolates were imipenem-resistant, and all except one harbored the bla OXA-23 gene. Kor-GLASS provided comprehensive AMR surveillance data, and the defined molecular mechanisms of resistance helped us to better understand AMR epidemiology. Comparative analysis with other GLASS-enrolled countries is possible owing to the harmonized system provided by GLASS.ope

The Clinical Outcomes of Off-Pump Coronary Artery Bypass Grafting in the Octogenarians

Background: With the increasing age of the population, coronary artery bypass grafting in the elderly patients is becoming common. Off-pump coronary artery bypass grafting (OPCAB) has been proven to be less morbidity and to facilitate early recovery. The elderly patients may have benefits by avoiding the adverse effects of the cardiopulmonary bypass. The purpose of this study is to evaluate our results of OPCAB in elderly patients. Material and Method: A retrospective chart review was carried out for 12 patients aged over 80 years who underwent isolated OPCAB from January 2001 and March 2004. Data were collected risk factors for disease, extent of coronary disease, and in-hospital outcomes. Postoperative graft patency was evaluated in 9 patients by multi-slice computed tomography. Result: Eleven patients had triple vessel disease or left main disease. Four patients were suffered from preoperative CVA, and 4 patients had chronic obstructive pulmonary disease. Two patients had myocardial infarction (MI), among them 1 patient was suffered from pulmonary edema after preoperative MI. There was no perioperative death, perioperative MI, and no ventricular arrhythmia. Also there was no perioperative stroke and renal failure. But there was one deep sternal infection who recovered by treating of muscle flap. Atrial fibrillation was newly developed in 1 patient, but was well controlled by medication. Mean intubation time was 15.9±4.4 (8∼20 hrs) hrs and mean ICU stay was 2.9±0.8 (2∼4 days) days. Mean hospital day was 21.6±14.3 (13∼56 days) days. Postoperative mean CK-MB was 11.3±14.1 ng/mL. Early postoperative graft patency rate was 100% (24/24). Follow-up was completed in all patients. In this time, there was no patients with angina or death. Conclusion: The results of this study suggest that OPCAB reduces morbidity and favors hospital outcomes. Therefore, OPCAB is safe, reasonable and might be preferable operative strategy in elderly patients.ope

Klebsiella pneumoniae Carbapenemase Producers in South Korea between 2013 and 2015

Between 2014 and 2015, the Klebsiella pneumoniae carbapenemase (KPC) was becoming endemic in South Korea. To assess this period of transition, we analyzed KPC producers in terms of molecular epidemiology. A total of 362 KPC-producing Enterobacteriaceae strains, including one from 2013, 13 from 2014, and 348 from 2015, were actively collected from 60 hospitals throughout the peninsula. Subtypes of KPC were determined by PCR and direct sequencing, and isotypes of Tn4401 (the transposon flanking the blaKPC gene) were specified by PCR using isotype-specific primers and direct sequencing. Sporadic occurrence of KPC-producing Enterobacteriaceae was initially observed around Seoul, which is the most crowded district of the country, and these strains rapidly disseminated in 2014, to the other parts of the country in 2015. The bacterial clones responsible for the extreme epidemiological transition were K. pneumoniae ST307 (46.2%) and ST11 (21.3%). Less frequently, E. coli (4.7%), Enterobacter spp. (1.4%), and other Enterobacteriaceae members (1.7%) producing the enzyme were identified. The blaKPC-2 gene bracketed by Tn4401a (72.1%) was the most prevalent mobile genetic element responsible for the dissemination, and the same gene carried either by Tn4401b (2.2%) or Tn4401c (6.6%) was identified at a lesser frequency. The genes blaKPC-3 (1.6%) and blaKPC-4 (6.4%), both flanked by Tn4401b, were occasionally identified. This study showed endemic dissemination of KPC producers in 2015 due to a clonal spread of two K. pneumoniae strains. Further systemic surveillance is needed to monitor dissemination of KPC-producers.ope