• 대한화학회지
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• 제38권8호
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• pp.603-607
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• 1994

새로운 cephalosporin 항생물질인 7-[(3,4-dihydro-6-methoxycarbonyl-2,2-dimethyl-2H-1,4-thiazin-3-yl)acetamido]-3-[(substituted pyrimidin-2-yl)thiomethyl]-3-cephem-4-carboxylic acid derivatives(2a∼2d)유도체들을 합성하였다. 7-ACA의 3-위치에는 pyridinylthiomethyl기를 도입시키고, 7-위치에는 thiazine를 치환시켜서 구조 변화에 대한 항균 활성을 측정하였다. 그 결과 이들 유도체들은 기준물질인 cefotaxim보다 낮은 항균력을 나타내었다.

• 마이크로전자및패키징학회지
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• 제7권1호
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• pp.41-49
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• 2000

Flip chip assembly on organic substrates using ACAs have received much attentions due to many advantages such as easier processing, good electrical performance, lower cost, and low temperature processing compatible with organic substrates. ACAs are generally composed of epoxy polymer resin and small amount of conductive fillers (less than 10 wt.%). As a result, ACAs have almost the same CTE values as an epoxy material itself which are higher than conventional underfill materials which contains lots of fillers. Therefore, it is necessary to lower the CTE value of ACAs to obtain more reliable flip chip assembly on organic substrates using ACAs. To modify the ACA composite materials with some amount of conductive fillers, non-conductive fillers were incorporated into ACAs. In this paper, we investigated the effect of fillers on the thermo-mechanical properties of modified ACA composite materials and the reliability of flip chip assembly on organic substrates using modified ACA composite materials. For the characterization of modified ACAs composites with different content of non-conducting fillers, dynamic scanning calorimeter (DSC), and thermo-gravimetric analyser (TGA), dynamic mechanical analyzer (DMA), and thermo-mechanical analyzer (TMA) were utilized. As the non-conducting filler content increased, CTE values decreased and storage modulus at room temperature increased. In addition, the increase in the content of filler brought about the increase of $Tg^{DSC}$ and $Tg^{TMA}$. However, the TGA behaviors stayed almost the same. Contact resistance changes were measured during reliability tests such as thermal cycling, high humidity and temperature, and high temperature at dry condition. It was observed that reliability results were significantly affected by CTEs of ACA materials especially at the thermal cycling test. Results showed that flip chip assembly using modified ACA composites with lower CTEs and higher modulus by loading non-conducting fillers exhibited better contact resistance behavior than conventional ACAs without non-conducting fillers.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2009년 추계학술발표대회
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• pp.73-73
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• 2009

In this sutdy, a new class ACA(Anisotropic Conductive Adhesive) with low-melting-point alloy(LMPA) and self-organized interconnection method were developed. This developed self-organized interconnection method are achieved by the flow, melting, coalescence and wetting characteristics of the LMPA fillers in ACA. In order to observe self-interconnection characteristic, the QFP($14{\times}14{\times}2.7mm$ size and 1mm lead pitch) was used. Thermal characteristic of the ACA and temperature-dependant viscosity characteristics of the polymer were observed by differential scanning calorimetry(DSC) and torsional parallel rheometer, respectively. A electrical and mechanical characteristics of QFP bonding were measured using multimeter and pull tester, respectively. Wetting and coalescence characteristics of LMPA filler particles and morphology of conduction path were observed by microfocus X-ray inspection systems and cross-sectional optical microscope. As a result, the developed self-organized interconnection method has a good electrical characteristic($2.41m{\Omega}$) and bonding strength(17.19N) by metallurgical interconnection of molten solder particles in ACA.

• Bulletin of the Korean Chemical Society
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• 제32권2호
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• pp.407-410
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• 2011

An isolable activated ester, diethyl thiophosphoryl [(Z)-(2-aminothiazol-4-yl)-2-(methoxyimino)acetate (9a, DAMA) was prepared in high purity, which was at least stable for 7 d at $25^{\circ}C$ and 6 months at $5^{\circ}C$. Its reaction with 7-ACA (4) in the presence of tributylamine in i-PrOH provided cefotaxime (1) of high purity in good yield. Preparation of DAMA and its reaction with 7-ACA (4) to 1 was performed in one-pot manner, respectively with minimal unit operations of stirring and filtration.

• 약학회지
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• 제30권6호
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• pp.294-300
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• 1986

New antibiotics having moieties of penicillanic acid, cephalosporanic acid and ampicillin on both ends of the central polyalkylene were synthesized by reacting 6-aminopenicillanic acid (6-APAl), 7-amino cephalosporanic acid (7-ACA) and ampicillin with hexamethylene diisocyanate and sebacoyl chloride, respecetively. Antibiacterial activities of the compounds were also investigated.

• KSBB Journal
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• 제10권3호
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• pp.264-270
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• 1995

Trigonopsis variabilis는 버l타락탐 항생제인 cephalosporin C (ceph C)를 ${\alpha}$-keto-adipyl-7 a aminocephalosporanic acid(AKA-7 ACA)로 생변 환하는 강력한 D-amino acid oxidase 효소를 갖고 있다. 본 연구는 이 D-AAO 효소의 유전자를 추출하기 위하여 polymerase chain reaction (PCR)을 사용하였다. PCR 단편을 콜로닝하기 위하여 Taq D DNA polymerase, Klenow, T4 DNA polymerase I, Alkaline phosphatase Calf Intestinal와 T4 kinase 의 효소반응을 이용하여 4가지의 방법을 샤용한 결 과, blunt - end 의 PCR fragment 를 phosphory­l lation하고 blunt -end의 pUC18 plasmid를 dephos phorylation 한 후 ligation 한 것 이 가장 좋은 클로 닝 효율을 보였다. Ceph C에 대한 D-AAO 효소의 활성은 재조합 E. coli의 세포추출액과 permea bilized cells에서 모두 확인할 수 있었다.

• Journal of Korean Neurosurgical Society
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• 제66권6호
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• pp.743-747
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• 2023

Ruptured intracranial aneurysms in infants are rare and infantile fusiform anterior cerebral artery (ACA) aneurysms are much rarer. In this report, we described the case of a 7-month-old infant with a ruptured fusiform ACA aneurysm who presented with seizure and underwent endovascular treatment. The patient was initially in a coma and the neurologic condition did not improve after treatment. The clinical characteristics of the case and literature review were discussed.

• 한국미생물·생명공학회지
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• 제32권3호
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• pp.224-229
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• 2004

토양으로부터 강력한 CAH activity를 갖는 균주를 분리하여, 생화학적, 배양학적, 전자현미경 동정을 한 결과, Bacillus sphaericus로 확인되었으며, 이를 B. sphaericus 366M-9로 명명하였다. 또한 이 균으로부터 최초로 cephalosporin-C deacetylase(CAH)를 분리 정제하였다. 정제수율은 약 7.5% 였으며, B. sphaericus 366M-9에서 분리한 CAH-9의 최적활성 온도는 $50^{\circ}C$였으며, 효소안정 온도구간은 30～$50^{\circ}C$이다. 또한 최적 활성 pH는 7.0이었으며, 효소안정 pH구간은 pH 6.0～8.0으로 90% 이상의 잔존 활성도를 나타내었다. 효소반응속도에 미치는 기질의 영향에서는 $K_{m}$ 값은 0.87 mM 이며,$ V_{max}$는1.22 unit/ml이었다.다.

• Applied Biological Chemistry
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• 제40권1호
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• pp.23-29
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• 1997

7-Aminocephalosporanic acid (7-ACA)로부터 새로운 구조의 ${\beta}-lactam$계 항생물질을 개발하기 위한 목적으로 7- ACA의 $C_3$ 위치에 thio1기를 도입하고 $C_7$위치 aminothiazole기를 결합시킨 신규 화합물 (YH-487)을 제조한 다음 이의 구조 확인과 항균활성, 작용기전, ${\beta}-lactamase$에 대한 안정성, 다른 항생물질과의 병용 효과 등을 검토한 결과 YH-487은 세균에 대한 항균활성과 살균력이 CTX보다 우수한 신규의 제3세대 cephem계 물질이었다. 또한 YH-487의 살균작용 메카니즘은 PBP-lA, PBP-1B와 PBP-3의 친화성에 의한 세균의 세포벽 합성저해에 의한 것이었다. ${\beta}-lactamase$에 대한 안정성은 E. coli가 생성하는 TEM-1 type Pcase에는 cefotiam 또는 cefotaxime과 동등한 수준이었으나 Stahylococcus aureus가 생성하는 Pcase와 Pseudomonas aeruginosa가 생성하는 CSase와 Proteus vulgaris 생성의 Cxase에는 cefotiam 또는 cefotaxime 보다 높은 안정성을 나타내어 ${\beta}-lactamase$에 대해 매우 안정한 약물임을 나타내었다. 한편 다른 항생물질과의 병용효과 실험결과는 gentamicin, tobramycin 그리고 amikacin과 병용시 녹농균에 대하여 상승효과가 인정되었고 Enterobacter cloacae에 대하여는 amikacin과 병용시 상승작용이 있었다.

• Journal of Korean Neurosurgical Society
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• 제37권3호
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• pp.207-212
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• 2005

Objective: Classically, single photon emission tomography is known to be the reference standard for evaluating the hemodynamic status of patients with moyamoya disease. Recently, T2-weighted perfusion magnetic resonance(MR) imaging has been found to be effective in estimating cerebral hemodynamics in moyamoya disease. We aim to assess the utility of perfusion-weighted MR imaging for evaluating hemodynamic status of moyamoya disease. Methods: The subjects were fourteen moyamoya patients(mean age: 7.21 yrs) who were admitted at our hospital between Sep. 2001 to Sep 2003. Four normal children were used for control group. Perfusion MR imaging was performed before any treatment by using a T2-weighted contrast material-enhanced technique. Relative cerebral blood volume(rCBV) and time to peak enhancement(TTP) maps were calculated. Relative ratios of rCBV and TTP in the anterior cerebral artery(ACA), middle cerebral artery(MCA) and basal ganglia were measured and compared with those of the posterior cerebral artery(PCA) in each cerebral hemispheres. Using this data, we analysed the hemodynamic aspect of pediatric moyamoya disease patients in regarding to the age, Suzuki stage, signal change in FLAIR MR imaging, and hemispheres inducing symptoms. Results: The mean rCBV ratio of ACA, MCA did not differ between normal children and moyamoya patients. However the significant TTP delay was observed at ACA, MCA territories (mean = 2.3071 sec, 1.2089 see, respectively, p < 0.0001). As the Suzuki stage of patients is advanced, rCBV ratio is decreased and TTP differences increased. Conclusion: Perfusion MR can be applied for evaluating preoperative cerebral hemodynamic status of moyamoya patients. Furthermore, perfusion MR imaging can be used for determine which hemisphere should be treated, first.