2,3,5-Triphenyltetrazolium Chloride 첨가 미량액체배지희석법에 의한 항균제 감수성 검사 방법의 평가

이대동,이은엽,정석훈,장철훈 대한임상미생물학회 2007 Annals of clinical microbiology Vol.10 No.1

Background: The broth microdilution susceptibility testing method is considered a standard for determining minimum inhibitory concentrations, and the addition of the redox indicator 2,3,5-triphenyltetrazolium chloride (TTC) to the broth microdilution method simplifies and increases its objectivity. The current study evaluated the usefulness of a TTC-modified broth microdilution method for antimicrobial susceptibility test of frequently encountered clinical isolates. Methods: The minimal inhibitory concentrations (MICs) of 10 antimicrobials for 111 clinical isolates of four bacterial species, Staphylococcus aureus, Escherichia coli, Enterobacter cloacae, and Acinetobacter baumannii, were investigated by a modification of the Clinical and Laboratory Standards Institute (CLSI)-recommended broth microdilution method with the addition of 2,3,5-triphenyltetrazolium chloride (TTC). The inhibitory effects of TTC against 192 strains of 22 bacterial species isolated from clinical specimens were also evaluated. Results: The number of colonies of all 192 strains of 22 bacterial species grown on TTC-containing Mueller-Hinton agar did not differ from those grown on Mueller-Hinton agar only. The MICs with TTC were within 2 dilutions of those obtained by the CLSI method in 569 (97.6%) of 583 organism-timicrobial agent combinations. Conclusions: The colorimetric MIC method using TTC may be a useful surrogate of antimicrobial susceptibility testing for most of the frequently isolated bacteria.

Thermal Analysis and Temperature Characteristics of a Braking Resistor for High-speed Trains for Changes in the Braking Current

이대동,강현일,심재명 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.67 No.6

Electric brake systems are used in high-speed trains to brake trains by converting the kinetic energy of a railway vehicle to electric energy. The electric brake system consists of a regenerative braking system and a dynamic braking system. When the electric energy generated during the dynamic braking process is changed to heat through the braking resistor, the braking resistor can overheat; thus, failures can occur to the motor block. In this paper, a braking resistor for a highspeed train was used to perform thermal analyses and tests, and the results were analyzed. The analyzed data were used to estimate the dependence of the brake currents and the temperature rises on speed changes up to 300 km/h, at which a test could not be performed.

Temperature Characteristics Analysis of HIV Partial Disconnection Wire

이대동,심재명,이유성,정윤미,김영달 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.67 No.6

Electric fires are caused mainly due to short circuits, overloads, and electric leakage. Of the causes, short circuits are caused by deteriorated insulation, poor contacts, and pressure damage. A partially disconnected wire refers to the status in which the wire section is partially cut, thus reducing the contact area compared to the normal state. Causes of partially disconnected wires, e.g., poor wire contacts and pressure damage, occur mostly in the wiring and in the device’s contact area, and they locally increase the resistance, thus triggering thermal changes. Thus, this study simulated damage to a 450/750 V heat-resistant polyvinyl-chloride-insulated (HIV) wire used for preventing electric fires and analyzed the temperature characteristics of normal wires and partially disconnected wires.

소형 풍력발전시스템을 위한 계통연계형 인버터에 관한 연구

李大東,沈在明,張錫九 한밭대학교 2004 한밭대학교 논문집 Vol.21 No.-

We imported technology from abroad and studied grid connected type wind power generation owing to the lack of technology, but nowadays we conduct researches in many quarters because of national supporting policy. However, the research speed is delayed by burden for research expense which wind power generation is huge. Therefore, in order to experiment on various kinds of the wind turbine, generator, and converter easily, the development of wind power system is demanded powerfully among research workers. In this paper, in order to satisfy this need, I suppose a new simulation development environment. The electric power generated by wind is changing, so by using the converter, schedule electric power must be provided. Therefore, in this paper, I explained an element of the converter of the wind power generation system by showing two examples. First, Diode rectifier and current controlled voltage source inverter by using IGBT(Insulated Gate Bipolar Transistor) element was used in the wind power generation system. Second, rectifier for control by using IGBT and current controlled voltage source inverter by using IGBT element was connected the grid. Simulation for two examples of grid connected type wind power generation system uses PSCAD/EMTDC and analyzed the result.

JIT/TQM 생산시스템을 위한 라인중단전략

이대동,신두영 조선대학교 경영경제연구소 1994 經營經濟硏究 = Management and economics research Vol.17 No.1

지역사회획득 폐렴에서 레지오넬라 감염의 빈도

이대동,송은주,이선민,이은엽,김윤성,이민기,김정만,이혜경,장철훈 대한진단검사의학회 2005 Annals of Laboratory Medicine Vol.25 No.6

Background : Legionella spp. cannot be cultivated in routine bacterial culture media, causing underdiagnosis of community-acquired pneumonia (CAP) due to this microorganism. The purpose of this study was to evaluate the prevalence of legionellosis in patients with CAP by using several diagnostic techniques. Methods : Patients’ sputum, serum and urine samples were collected from 38 patients with CAP in Pusan National University Hospital during November 2002 to May 2004. The laboratory procedures for diagnosis of legionellosis was performed by sputum cultures, urine antigen tests, nucleic acid amplification tests, and serologic indirect immunofluorescence antibody tests. Results : Legionella pneumonia was diagnosed in 2 of the 38 patients (5.3%); one was L. pneumophila serogroup 1 positive in urine, and the other was serum IgG antibody positive for L. micdadei. Conclusions : Legionellosis may play an important role in adult CAP in Korea. The diagnosis of legionellosis may require various testing methods, such as sputum culture, urine antigen test, nucleic acid amplification test, and serologic antibody test. 배경 : 레지오넬라 감염증은 임상 가검물에서 원인균의 분리가까다롭고 표준 세균배지에서 자라지 않는 등 통상적인 미생물학적 검사 방법으로 잘 검출되지 않기 때문에 지역사회획득 폐렴의원인으로 잘 진단되지 않는다. 이에 본 연구에서는 본원에 입원한지역사회획득 폐렴환자를 대상으로 현재 알려진 여러 검사 방법들을 통하여 지역사회획득 폐렴에서 레지오넬라의 감염 비율을 확인하고자 하였다. 방법 : 2002년 11월부터 2004년 5월까지 부산대학교병원을 방문한 지역사회획득 폐렴 환자 38명을 대상으로 하여 배양, 소변항원검사, 핵산증폭검사, 혈청 항체검사를 이용하여 레지오넬라감염 여부를 조사하였다. 결과 : 총 38명 중 1명에서는 L. micdadei에 대한 혈청 항체가 가 IgG 1:256 양성을 보였고, 1명에서는 소변 항원검사에서 L. pneumophila 혈청형 1에 양성을 보여 총 5.3%의 양성률을 보였다. 결론 : 지역사회획득 폐렴에서 레지오넬라 감염증이 드물지 않으며, 이의 진단을 위해서는 배양, 소변항원검사, 핵산증폭검사, 혈청항체검사 등 여러가지 검사를 병행해서 실시할 필요가 있을 것으로 생각한다.

BacT/Alert3D 장비를 이용한 혈액배양에서 FAN-A 호기성 배양병의 성능 평가

이대동,이선민,최재철,이은엽,장철훈 대한임상미생물학회 2005 Annals of clinical microbiology Vol.8 No.2

Background: This study was designed to evaluate the performance of FAN-aerobic bottles (FANA) in comparison with standard-aerobic bottles (STD-A) in BacT/Alert3D blood culture system. Methods: A total of 596 pairs of blood cultures, submitted from Emergency Department of Pusan National University Hospital between July and December 2004, were evaluated. In addition to the routine blood culture protocol using standard blood culture bottles, 5 ml of blood samples was inoculated into FAN-A bottles for this study. Results: Microorganisms were grown in 84 (14.1%) of 596 cultures; of those, 15 were positive in STD-A only (2.5%), 35 in FAN-A only (5.9%), and 34 in both (5.7%). The positive rate in FAN-A bottles was significantly higher than that in STD-A bottles ( P<0.001). The species of isolates and detection time showed no difference between the blood culture bottles. Conclusion: In the BacT/Alert3D blood culture system, the use of FAN-A bottles instead of the standard aerobic bottles should yield a higher positive rate.

A Study on Salt Damage Pollution Forecasting by Measuring Leakage Current

이대동,현동석,김영달 한국조명.전기설비학회 2010 조명·전기설비학회논문지 Vol.24 No.7

Faults due to salt damage prevent the provision of stable power supply because they affect large areas and require much time and man power for recovery. Korea, three sides of which are surrounded by sea, is especially exposed to the impact of sea winds and typhoons. Therefore, salt damage to power facilities is one of the greatest problems of Korea’s power system. To prevent salt damage pollution of insulators, the salt damage deposit on the insulators is regularly measured, and the insulators are washed when their salt damage deposits are expected to reach a critical level. When salt is detected on the insulators, however, errors are likely to occur according to different workers and environments. Therefore, a leakage current measurement method was proposed in this study to check the salt damage pollution level and reduce these errors.

헌혈채혈현장에서 ABO혈액형 판정오류 개선 경험

이대동,김은진,서유경,조민지,조용준,이미경 대한수혈학회 2017 大韓輸血學會誌 Vol.28 No.2

Background: In the Korean Red Cross Blood Center, ABO blood typing are routinely performed only via red cell grouping at blood donations sites. However, when an error occurs in this process, it is impossible to issue a blood product contrary to the result of the blood type of the Blood Laboratory Center, thereby resulting in delayed supply. Therefore, efforts are needed to reduce typing errors at blood donation sites. Methods: We analyzed 656,786 donor screenings between January 1, 2016 and December 31, 2016;we also analyzed the statistical data of donor ABO typing between 2013 and 2015. To reduce ABO typing error, we notified and trained nurses at Busan, Gyeongnam, Ulsan, and Daegu-Gyeongbuk Blood centers in June, 2016. We tried to confirm the improvement of ABO typing error at blood donation sites by comparing ABO typing before and after training. For data comparison, chi-square test was conducted (95% confidence interval, 0.05 significant level). Results: The blood typing error rate was significantly lower (P=0.003) four months after training (0.005%) than before training (0.015%), and the blood typing error rate was significantly higher for the first blood donor (P<0.001). Conclusion: Educational training for nurses at blood donation sites may be effective in reducing ABO typing error. Continuous and regular training seems to be needed in future to reduce ABO typing error.

미세원주응집 자동화 장비에 의한 비예기항체 선별시 ‘판정불가' 감소방안

이대동,김대성,김동욱,이명환,김온정,김희동,허광,이미경 대한수혈학회 2018 大韓輸血學會誌 Vol.29 No.1

Background: Among the results of an unexpected antibody screening test using IH-1000, ‘undeterminable’ results can be obtained. Repeated tests not only use reagents and consumables but also cause a turnaround time delay. Therefore, it is important to reduce the ‘undeterminable’ results and to determine the effects. Methods: From January to early June, 2016, 2,872 cases/259,455 tests (1.11%) of ‘undeterminable’ were detected in the screening test. The factors considered to affect the ‘undeterminable’ were classified into four categories: ① reagent, ② consumables, ③ inspection environment & specimen, and ④ enhancing the equipment management. For data comparison, a chi-square test was conducted (95% confidence interval, 0.05 significant level). Results: The incidence of ‘undeterminable’ cases decreased from 1.11% before management to 0.66% (P<0.001) after Pool Cells management. The consumption of ‘LISS/Coombs Card’ decreased from 1.07% before management to 0.51% (P<0.001) after management. By maintaining a clean inspection environment and strengthening sample management, the rate decreased from 1.11% before management to 0.66% (P<0.001) after management. On the other hand, there was no difference in the incidence of ‘undeterminable’ between before and after IH-1000 management reinforcement. Conclusion: Among the factors predicted to affect the decrease in the incidence of ‘undeterminable’, the management of Pool Cells and keeping the inspection environment clean as well as improving sample management contributed the most to the reduced ‘undeterminable’. Improvements in the management of consumables, and removing dust from the inside of the equipment, had a positive impact. A continuous quality improvement theme has been adopted and it is helpful for managing and improving the predicted factors.