• 한국전산구조공학회논문집
• /
• 제23권5호
• /
• pp.543-550
• /
• 2010

내진설계는 타 설계의 요구사항, 즉 각 구조부재의 설계강도가 소요강도 이상이어야 한다는 것을 만족해야 하는 동시에 지진발생시 구조물의 항복과정을 규명하여 제시하여야 한다. 이러한 요구사항이 추가되는 이유는 타 하중과는 차별되는 지진하중의 불확실성이다. 이 연구에서는 일반교량을 해석대상교량으로 선정하고 연결부분의 설계를 수행하여 연성파괴메카니즘을 확보하는 과정을 제시하였다. 이와 같은 과정으로부터 구조부재의 강도 증가 또는 지진저감장치 도입 등의 비용증가 없이 타 설계에서 요구되는 구조부재의 강도 이내에서 내진성능을 확보할 수 있다는 것을 확인하였다.

• Journal of Microbiology
• /
• 제40권2호
• /
• pp.98-103
• /
• 2002

Twenty-eight clinical isolates of Escherichia coil, composed of thirteen norfloxacin resistant isolates (MIC of >16${\mu}$g/ml), one intermediately resistant isolate (MIC of 8${\mu}$g/ml), and fourteen susceptible isolates (MIC of <4${\mu}$g/ml), were randomly selected to study the norfloxacin resistance mechanism and phylogeny in clinical isolates in Korea. Eleven nofloxacin resistant isolates and one susceptible isolate were multi-drug resistant (MDR). Every norfloxacin resistant isolate with MIC higher than 32${\mu}$g/ml had the same three mutations: Ser83\longrightarrowLeu and Asp87\longrightarrowAsn or Tyr in GyrA and Ser80\longrightarrowIle in ParC. Whereas a resistant isolate with MIC of 16${\mu}$g/ml had three mutations but Asp87 in GyrA was replaced with Gly instead of Asn. The intermediately resistant isolate had the same two mutations in GyrA but a different mutation in ParC, Glu84\longrightarrowLys. Among the susceptible isolates, two isolates with MIC of 4${\mu}$g/ml had one mutation: Ser83\longrightarrowiLeu in GyrA, and no mutation was found in the susceptible isolates. Resistant isolates showed higher efflux activity than the susceptible ones, with random amplification of polymorphic DNA (RAPD), six susceptible isolates form a separate group from the rest of the isolates.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2004년도 추계학술대회 논문집 전기물성,응용부문
• /
• pp.3-8
• /
• 2004

The Pulse Width Modulation (PWM) Inverter plays an important role in express locomotive. Especially after traction motors are fed by fast switching inverters, the interturn insulation is destroyed more heavily. However, a new type of polyimide corona resistant film is developed and used in insulation of traction motors. In order to investigate the service life of this kind of traction motor, the mechanism and characteristics of dielectric breakdown of polyimide corona resistant are studied in the paper. Experiments have been carried out on specimen according to the condition of traction motor. The breakdown point of tested sample film is analyzed through energy spectrum analysis and electron microscopic photograph. At last, it is presented that the characteristics and mechanism of breakdown of polyimide corona resistance film.

• Toxicological Research
• /
• 제27권2호
• /
• pp.85-93
• /
• 2011

Selective estrogen receptor modulators (SERMs) are synthetic molecules which bind to estrogen receptors (ER) and can modulate its transcriptional capabilities in different ways in diverse estrogen target tissues. Tamoxifen, the prototypical SERM, is extensively used for targeted therapy of ER positive breast cancers. Unfortunately, the use of tamoxifen is associated with acquired resistance and some undesirable side effects. This study investigated the availability of the conventional SERMs on the TAM-resistance breast cancer cells. SERMs showed more effectiveness in MCF-7 cells than tamoxifen resistant cells, except toremifene and ospemifene. Especially, toremifene was more efficacious in tamoxifen resistant cells than MCF-7. Ospemifene had similar cytotoxic activity on the two types of breast cancers. The other SERMs used in this experiment didn't inhibit efficiently the proliferation of tamoxifen resistant cells. These results support the possibility to usage of toremifene on tamoxifen resistant cancer. The effectiveness by toremifene on tamoxifen resistant cells might be different pathways from the apoptosis and the autophagy. Further study should be needed to elucidate the underlying mechanism of effect of toremifene on tamoxifen resistant cancer.

• 한국미생물생명공학회:학술대회논문집
• /
• 한국미생물생명공학회 2000년도 Proceedings of 2000 KSAM International Symposium and Spring Meeting
• /
• pp.26-32
• /
• 2000

• 한국동물학회:학술대회논문집
• /
• 한국동물학회 1997년도 한국생물과학협회 학술발표대회
• /
• pp.79-79
• /
• 1997

No Abstract, See Full Text

• 한국지진공학회논문집
• /
• 제6권4호
• /
• pp.1-6
• /
• 2002

일반설계에서 요구하는 구조물의 안전성은 탄성영역에서 일정수준의 안전계수를 확보하여 만족된다. 그러나 내진설계에서의 안전성은 소성영역에서 구조물의 형상에 따라 특정한 연성파괴메카니즘을 유도하여 확보하도록 요구하고 있다. 그러므로 이러한 안전성은 구조물의 기본설계단계에서 여러 개의 대안을 가지고 비교, 검토를 수행하여 확보되어야 하며 실시설계단계에서 이를 확인하는 작업이 이루어져야 한다. 이 연구에서는 일반도로교량을 대상으로 하여 기본설계와 실시설계에 사용하는 모델을 설정하였으며 양 모델의 동적거동특성인 주기와 모드형상을 비교하고 다중모드스펙트럼해석을 적용하여 파괴메카니즘을 규명하였다. 기본설계와 실시설계에 사용하는 모델로 각각 확인한 파괴메카니즘을 비교하여 기본설계모델의 타당성을 입증하고 실무에 적용할 수 있는 내진해석모델로 제시하였다.

• Natural Product Sciences
• /
• 제6권1호
• /
• pp.36-39
• /
• 2000

Acorenone, a diterpene isolated from Acorus gramineus, showed strong resistance inhibitory activity against multi-drug resistant microorganisms such as Staphylococcus aureus SA2, which has resistance to 10 usual antibiotics including chloramphenicol (Cm). At the level of $5\;{\mu}g/ml$ when combined with $50\;{\mu}g/ml$ of Cm. Bacterial resistance to Cm is due to the presence in resistant bacteria of an enzyme, chloramphenicol acetyltransferase (CAT), which catalyses the acetyl-CoA dependent acetylation of the antibiotic at C-3 hydroxyl group. To elucidate the mechanism of resistant inhibitory effect, the acorenone which had the strongest resistant inhibitory activity, was investigated on the CAT assay. As the result, the combination of Cm and acorenone showed the strongest inhibitory activity on CAT as noncompetitive and dose dependent manner.

• 약학회지
• /
• 제24권1호
• /
• pp.1-10
• /
• 1980

Viomycin inhibited polypeptide biosynthesis, initiation complex formation and translocation of peptidyl-tRNA on ribosomes derived from a sensitive strain of Mycobacterium smegmatis (R-15), but not significantly on ribosomes from viomycin-resistant mutants(R-31 and R-43). The inhibition of translocation was stronger than that of initiation complex formation in the sensitive strain. The binding of [$^{14}C$] tuberactinomycin O, a viomycin analog, to ribosomal particles was studied by Millipore filter method. The sensitive ribosome exhibited higher affinity for the antibiotic than the resistant ribosomes. The resistance was localized on the large ribosomal subunit in a mutant(R-31), and on the small subunit in another mutant(R-43). The binding of the drug to the sensitive ribosomal subunit was markedly reduced by combination with the resistant pair subunit, and the entire ribosome became resistant to the antibiotic.

• Tuberculosis and Respiratory Diseases
• /
• 제85권2호
• /
• pp.111-121
• /
• 2022

Multidrug-resistant tuberculosis (MDR-TB) is caused by an organism that is resistant to both rifampicin and isoniazid. Extensively drug-resistant TB, a rare type of MDR-TB, is caused by an organism that is resistant to quinolone and one of group A TB drugs (i.e., linezolid and bedaquiline). In 2018, the World Health Organization revised the groupings of TB medicines and reclassified linezolid as a group A drug for the treatment of MDR-TB. Linezolid is a synthetic antimicrobial agent in the oxazolidinone class. Although linezolid has a good efficacy, it can cause substantial adverse events, especially hematologic toxicity. In both TB infection and linezolid mechanism of action, mitochondrial dysfunction plays an important role. In this concise review, characteristics of linezolid as an anti-TB drug are summarized, including its efficacy, pathogenesis of hematologic toxicity highlighting mitochondrial dysfunction, and the monitoring and management of hematologic toxicity.