• Bulletin of the Korean Chemical Society
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• 제30권1호
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• pp.83-91
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• 2009

To develop new anticancer agents, 3-allylthio-6-aminopyridazine derivatives were synthesized from maleic anhydrides or phthalic anhydrides by formation of a pyridazine nucleus, dichlorination, allylthiolation and amination. The pyridazine nuclei were obtained by condensing a hydrazine monohydrate with maleic anhydride. An allylthio group as a pharmacologically active group was introduced into one side of a pyridazine ring. Arylalkylamines with benzene or pyridine moieties or heterocycloalkylamines with heterocycle moieties such as morpholine, piperidine, or pyrrolidine were also introduced into the para-position of allylthio pyridazine. These new compounds showed antiproliferative activities against SK-Hep-1 human liver cancer cells in MTT assays. These compounds are thus promising candidates for chemotherapy of hepatocellular carcinomas. Two compounds, 20c and 22a, showed higher potencies for inhibiting growth of hepatocellular carcinoma cells than did K6 ($ID_50$=1.08 mM). This suggests the potential anticancer activity of these two compounds.

• Journal of Microbiology
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• 제33권4호
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• pp.350-354
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• 1995

Saccharomyces cervisiae has a highly ordered ring of filaments that lies just inside the cytoplasmic membrane in the region of the mother-bud neck. Mutants defective in any one of the our cell division cycle genes (CDC3, CDC10, CDC11, CDC12) fail to form these filaments and exhibit a pleiotropic phenotype that includes failure to complete cytokinesis and abnormal bud growth. However, the role of the filament is not clear. In order to find out the role of filament, the similar gene in S pombe (called cdc103$\^$+) to the CDC3 was cloned and sequenced. Here I report the sequence analysis of the cdc103$\^$+/ ) to the CDC3 was cloned and sequenced. Here I report the sequence analysis of the cdc103$\^$+/. Comparison of the predicted amino acid sequences of cdc103$\^$+/ and CDC3 revealed that they share significant similarity (43% identity and 56% identity or similarity) to each other.

• Animal cells and systems
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• 제5권1호
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• pp.59-64
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• 2001

To understand the late gut development and differentiation, identification and characterization of target genes of homeotic genes involved in gut development are required. We have previously reported that homeodomain proteins can regulate expression of the cell proliferation-related genes. We investigated here the expression of the Drosophila proliferating cell nuclear antigen(PCNA) and E2F(dE2F) genes in larval and adult guts using transgenic flies bearing lacz reporter genes. Both PCNA and dE2F genes were expressed strongly in whole regions of the larval and adult guts including the esophagus, proventriculus, midgut and hindgut, showing higher expression in foregut and hindgut imaginal rings of larva. Nitric Oxide(NO) has been known to be involved in cell proliferation and tumor growth and also to have an antiproliferative activity. Therefore, we also investigated effects of NO on the expression of PCNA and dE2F genes in gut through analyses of lacz reporter expression level in the SNP (NO donor)-treated larval guts. Expressions of both PCNA and dE2F were greatly declined by SNP. The inhibitory effect of NO was shown in whole regions of the gut, especially in hindgut, while the internal region of proventriculus, esophagus, foregut imaginal ring and hindgut imaginal ring was resistant. Our results suggest that this inhibitory effect may be related with the antiproliferative activity of NO.

• 동력기계공학회지
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• 제13권6호
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• pp.95-101
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• 2009

The generator for gas turbine power generation consists of the rotor which generates magnetic field, the winding coil which is the path for the field current and the wedge and retaining ring which prevents the radial movement of the coil. Relatively severe deformation was observed at the coil end section during the inspection of the generator for peaking-load operation, and the thermal-electricity and the centrifugal force were evaluated by the simple modeling of the windings to find the cause. But the simulation stress was not sufficient to induce the coil plastic deformation. The analysis result seems to be applicable to the base-load generators which runs continuously without shut down up to a year, but there had been more deformation than simulated for the generator which is started up and shut down frequently. The cause of the coil deformation was the restriction of the expansion and shrinkage. The restriction occurs when the winding coil shrinks, and the stress overwhelms the yield stress and cause the plastic deformation. The deformation is accumulated during the start-ups and shut-downs and the thermal growth occurs. The factors which induce the coil restriction during the expansion and shrinkage should be reduced to prevent the unallowable deformation. The resolutions are cutting off the field current earlier during the generator shut-down, modifying the coil end section to remove the stress concentration and making the insulation plate inserted between the coil end section and the retaining ring have the constant thickness.

• 한국포장학회지
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• 제20권2호
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• pp.35-39
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• 2014

최근 커피시장의 고속 성장과 더불어 커피 포장용 가스배출 밸브(Degassing valve)의 수요도 급격히 증가하고 있다. 가스배출 밸브 주요 제조사(Big maker)로 Goglio사(이탈리아), Bosch사(독일) 및 Wipf사(스위스)가 있는데, 이들이 전세계 가스배출 밸브 포장재 소비량의 80%이상을 공급하고 있다. 국내시장 역시 대부분 수입에 의존하고 있어 수입 대체와 국내 포장산업 활성화를 위해 기술적 차별화와 동시에 선진기업 수준의 품질 성능을 갖춘 가스배출 밸브의 개발이 필요하였다. 따라서, 본 연구에서는 링타입 고무막을 적용하여 중앙 개폐형 가스배출 밸브(SP 밸브)를 개발하였으며, 실험을 통해 열림압력 820~1200 Pa, 닫힘압력 10~50 Pa, 가스 유동율 1.2~1.6 L/min로 Goglio 밸브와 대등한 수준의 품질 성능을 확인할 수 있었다. 또한, 식품용 기구 및 용기 포장 공전에 따른 밸브의 식품용기 품질 적합성을 확인하였으며, 향후 커피 포장용 밸브의 국내외 시장 점유율 확대와 함께 국내 발효식품 포장에 적용함으로써 한식 세계화에 기여할 것으로 기대된다.

• 생명과학회지
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• 제14권4호
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• pp.582-588
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• 2004

대전 근교의 농약으로 오염된 토양으로부터 파라치온을 분해하는 81균주를 분리한 후, 분리균주들중 파라치온 이용능이 가장 우수한 한 균주를 최종선별하였다. 최종 선별된 균은 생리생화학적 조사와 16S rRNA 염기 서열분석 등을 통하여 Pseudomonas rhodesiae H5로 확인되었다. Pseudomonas rhodesiae H5는 다양한 당을 이용하였으나 sorbose는 이용하지 못하였다. 또 이 균주는 ampicillin, spectinomycin, mito-mycin C에는 일부 저항성을 가지나 kanamycin, chloram-phenicol에는 저항성을 나타내지 않았다. 그리고 $BaCl_2$, LiCl, $MnSO_4$등의 중금속에서는 mg/ml 단위까지 강한 내성을 나타냈다. Pseudomonas rhodesiae H5의 최적 생장 조건은 3$0^{\circ}C$, pH 7.0 이었고, 이 균주는 파라치온의 organophosphate bond를 가수분해하여 p-nitrophenol를 생성한 후 ortho-ring cleavage를 거쳐 중심대사에 연결되는 것으로 추정된다.

• 한국환경생태학회지
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• 제15권4호
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• pp.344-353
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• 2002

백두대간 중 청옥산 능선부주변의 삼림군집구조를 분석하기 위하여 35개 조사구를 설정하고 식생조사를 실시하였다. Classification 기법 중 하나인 TWINSPAN을 이용하여 군락분리를 시도한 결과, 모두 신갈나무 우점종인 가운데 부 수종으로 군락 I은 물푸레나무. 군락 II는 당단풍, 군락 III은 미역줄나무, 군락 IV는 철쭉꽃으로 최종 분리되었다. 각각의 군락은 층위별 상대우점치를 이용하여 군집구조를 밝혔다. 연륜분석결과 청옥산 능선부 지역의 신갈나무의 임령은 약 30~150년 이상으로 밝혀졌다. 단위면적당(100$m^2$) 평균출현종수는 6.5$\pm$1.8종, 평균출현개체수는 68.3$\pm$39.9주이었다. 이상의 분석결과 청옥산 능선부의 신갈나무림은 노령임분으로 발전할 가능성이 있는 것으로 추측되었다.

• Structural Engineering and Mechanics
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• 제66권3호
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• pp.343-351
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• 2018

Brazilian disc test is one of the most widely used experiments in the literature of geo-mechanics. In this work, the pre-holed concrete Brazilian disc specimens are numerically modelled by a two-dimensional discrete element approach. The cracks initiations, propagations and coalescences in the numerically simulated Brazilian discs (each containing a single cylindrical hole and or multiple holes) are studied. The pre-holed Brazilian discs are numerically tested under Brazilian test conditions. The single-holed Brazilian discs with different ratios of the diameter of the holes to that of the disc radius are modelled first. The breakage load in the ring type disc specimens containing an internal hole with varying diameters is measured and the crack propagation mechanism around the wall of the ring is investigated. The crack propagation and coalescence mechanisms are also studied for the case of multi-holes' concrete Brazilian discs. The numerical and experimental results show that the breaking mechanism of the pre-holed disc specimens is mainly due to the initiation of the radially induced tensile cracks which are growth from the surface of the central hole. Radially cracks propagated toward the direction of diametrical loading. It has been observed that for the case of disc specimens with multiple holes under diametrical compressive loading, the breaking process of the modelled specimens may occur due to the simultaneous cracks propagation and cracks coalescence phenomena. These results also show that as the hole diameter and the number of the holes increases both the failure stress and the crack initiation stress decreases. The experimental results already exist in the literature are quit agree with the proposed numerical simulation results which validates this simulation procedure.

• Journal of Microbiology
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• 제43권4호
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• pp.325-330
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• 2005

Rhodococcus sp. strain YU6 was isolated from soil for the ability to grow on o-xylene as the sole carbon and energy source. Unlike most other o-xylene-degrading bacteria, YU6 is able to grow on p-xylene. Numerous growth substrate range experiments, in addition to the ring-cleavage enzyme assay data, suggest that YU6 initially metabolizes 0- and p-xylene by direct aromatic ring oxidation. This leads to the formation of dimethylcatechols, which was further degraded largely through meta-cleavage path-way. The gene encoding meta-cleavage dioxygenase enzyme was PCR cloned from genomic YU6 DNA using previously known gene sequence data from the o-xylene-degrading Rhodococcus sp. strain DK17. Subsequent sequencing of the 918-bp PCR product revealed a $98\%$ identity to the gene, encoding meth-ylcatechol 2,3-dioxygenase from DK17. PFGE analysis followed by Southern hybridization with the catechol 2,3-dioxygenase gene demonstrated that the gene is located on an approximately 560-kb megaplasmid, designated pJY J1

• 비파괴검사학회지
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• 제23권3호
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• pp.220-226
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• 2003

본 연구에서는 선박 용접구조물의 피로균열 발생 여부와 균열의 진전 상황을 실시간으로 모니터링하기 위한 기초 연구단계로서 선박의 전형적인 용접형태인 필렛용접부(fillet welded joint)의 피로시험에 대한 음향방출(Acoustic Emission, AE)기법의 적용성을 검토하였다. 필렛용접부의 피로시험에서 균열의 발생과 진전, 위치를 검출하기 위하여 AE 카운트(ring down count)와 위치표정(source location)등을 이용하였다. 시험결과 용접 토우(toe)부의 표면균열(surface crack)이 관통균열(through crack)로 발전하기 전까지의 AE 신호는 비교적 미약하게 나타났으나 균열의 발생시점과 위치를 카운트-위치표정으로 어느 정도 추정 가능함을 확인하였다. 표면균열이 브라켓의 두께방향으로 관통한 시점에서는 AE 카운트의 양이 급격히 증가하였으며 카운트-위치표정, 이벤트(event)-위치표정으로 균열의 위치와 발생시점을 명확하게 확인할 수 있었다. 또한 AE 위치표정과 클러스터(cluster) 기능을 이용하여 균열발생 위치 이외의 영역에서 검출된 신호는 잡음에 기인한 것으로 추정할 수 있었다.