A three-dimensional finite element analysis of two/multiple shots impacting on a metallic component

T. Hong,J.Y. Ooi,B.A. Shaw 국제구조공학회 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.29 No.6

This paper describes a three-dimensional dynamic finite element analysis of two/multiple shots impacting on a metallic component. The model is validated against a published numerical study. An extensive parametric study is conducted to investigate the effect of shot impacting with overlap on the resulting residual stress profile within the component, including time interval between shot impacts, separation distance between the impacting points, and impacting velocity of successive shots. Several meaningful conclusions can be drawn regarding the effect of shot impacting with overlap.

비효소적 핵산 분해 반응 : DNA에 대한 몇가지 Organometallointercalator Some Organometallointercalator for DNA

고동성,박미경,류형원,서일환 충남대학교부설 생명공학연구소 1991 생물공학연구지 Vol.1 No.-

Cu^(2+) -nalidixate 또는 Cu^(2+) -pipemidate 시스템을 H_2O_2 및 아스코르빈산 존재하 방사능-표지된 DNA와 함께 37℃에서 배양시키므로써 산-용해성 분해산물들이 생성되었다. 본성 DNA 대신 변성 DNA를 기질로 쓸 경우 금속-drug 시스템의 DNA 절단활성은 현저하게 감소되었다. 또한 본성 DNA에 대한 절단활성은 DNA에의 전형적 intercalator이며 metalloquinolones의 DNA에의 결합에 대한 경쟁적 방해제가 될 수 있는 ethidium bromide에 의하여 저하되었다. Quinolone 항생제가 금속이온과의 킬레이트 복합체 형성을 통하여 DNA의 두가닥 나사선 염기쌍 사이에의 삽간결합(intercalation)을 할 수 있으며 이와 같은 결합을 이룬 금속복합체는 DNA 가닥에 대한 산화성 절단활성을 가질 수 있음을 시사한다. Incubation of Cu^(2+)-nalidixate or Cu^(2+)-pipemidate system with DNA at 37℃ in the presence of H_2O_2 and ascorbic acid resulted in the production of acid-soluble counts from dadioactively labeled DNA. With denatured DNA as substrate, the cleavage activity of the metalloquinolone systems was far less than with the native DNA. The DNA cleavage activity of metalloquinolones was also decreased by the addition of ethidium bromide, which was known to be a typical intercalator of DNA and was shown to be a competitive inhibitor for the metalloquinolone binding to DNA. The data here suggest the DNA cleavage activity of quinolone antibiotics intercalated into DNA as metal chelate complexes.

可逆的 리간드 結合에 의하여 誘發되는 DNA의 응축-풀림 構造變移 : Spermine―DNA 複合體의 異例的 吸光度―溫度 樣相에 미치는 Urea의 影響 Effect of Urea on Anomalous Absorbance-Temperature Profile of Spermine-DNA Complex

高東成,李璨容 충남대학교 기초과학연구소 1986 연구논문집 Vol.6 No.-

Sperimine에 의하여 誘發되는 凝縮 DNA 構造의 安定化에 있어서 hydrophobic interaction의 重要性을 試驗하기 위하여 sperimine-DNA 複合體의 異例的 吸光度-溫度 樣相에 미치는 urea의 效果를 調査하였다. 그 結果 異例的 吸光度-溫度 樣相의 downward peak (trough) 領域에 이르는 相變移에 對한 cooperativity, enthalpy, midpoint의 값들이 Tm 領域의 값들 보다 urea에 敏感한 影響을 받았으며, urea의 濃度 增加에 따라 downward peak가 점차 사라졌다. 이 data는 異例的 吸光度-溫度 樣相을 構成하는 downward peak가 spermine에 의하여 誘發되는 hydrophobic interaction에 의한 凝縮된 tertiary structure의 形成을 나타내고 있다고 볼 수 있다. To investigate the importance of the hydrophobic interaction in the spermine-induced collapse of DNA to a compact structure, the effect of urea on the anomalous absorbance-temperature profile of calf thymus DNA has been investigated. With the increase of the urea concentration, the trough phase of the anomalous absorbance-temperature profile was eliminated eventually. The cooperativity, enthalpy, and the midpoint of the transition to the trough region are more sensitive to urea than those of the T_m-region transition. The present data of the adverse effect of urea, a hydrophobic environmental reagent, on the thermal stabilization of the condensed state of DNA, suggest that hydrophobic interaction may play an important role in the stabilization of the tertiary structure of the collapsed state of DNA.

가역적 리간드 결합에 의하여 유발되는 DNA의 응축-풀림 구조변이 : Ⅱ. DNA Conformation Probes로서의 Anionic Potential Reporter 분자의 구조 연구 Anionic Potential Reporter Molecules as Probes of DNA Conformation

고동성,서일환,이천배,서정인 충남대학교 기초과학연구소 1987 연구논문집 Vol.7 No.-

스페르민 존재하에서 nalidixic acid 및 oxolinic acid 등의 음이온성 quinolone 항생제는 ethidium bromide, proflavine 및 acridine orange 등의 양이온성 intercalative 리간드들과 마찬가지로 calf thymus DNA의 DNase 1에 대한 가수분해 반응성을 증가 시켰다. 그러나 본성 DNA와는 대조적으로 변성 DNA의 가수분해 반응성은 이들 양이온성 물감분자들에 의해서도 그리고 음이온성 quinolone 항생제들에 의해서도 영향 받지 않았다. 또한 스페르민 부재시에는 본성 DNA의 가분해 반응성도 이들 음이온성 drug에 의하여 영향 받지 않았다. 이들 데이터는 음이온성 quinolone 항생제가 스페르민과 intercalative 복합체를 형성하며 따라서 quinolone 항생제가 DNA conformation probe로서 사용될 수 있음을 시사하여 준다. 그러나 스페르민과 같은 polycation없이 음이온성 quinolone 항생제 자체만으로는 intercalation이 불가능함을 알 수 있다. 이와같은 이해는 분자궤도함수론적 고찰에 의하여 확인된다. The hydrolytic susceptibility of calf thymus DNA to DNase 1 was enhanced by such anionic Quinolone antibiotics as nalidixic acid and oxolinic acid in the presence of spermine, as well as by such cationic intercalative agents as ethidium bromide, profavine, and acridine orange. In contrast with the susceptibility of the native DNA, the susceptibility of the denatured DNA was not affected by the quinolone antibiotics, not either by the cationic dyes. Even the native DNA, however, was not influenced by the anionic antibiotics in its susceptibility to DNase 1 if spermine was omitted. The data here may lead to a tentative concusion that the quinolone antibiotics may form intercalative complexes with spermine, and that thereby the quinolone antibiotics can be used as probes of DNA conformation, whereas the anionic antibiotics alone without spermine may not have the intercalation activity, as supported by the MO data.

疎水性 環境이 Spermine에 의하여 誘發되는 凝縮된 DNA의 異例的 吸光度-溫度樣相에 미치는 影響

高東成,李天培,崔宇永,李璨容 충남대학교 1985 忠南科學硏究誌 Vol.12 No.2

We have investigated the effect of hydrophobic environmental reagents (urea and DMSO) on the anomalous absorbance-temperature profile of condensed DNA, induced by spermine. The cooperativity of the phase transition to the trough region in the anomalous absorbance-temperature profile is more sensitive to the hydrophobic environmental reagents than that of the melting region, and the trough peak size can be decreased by increased concentration of the hydrophobic reagents. The present data indicate the importance of hydrophobic interaction in the stabilization of the condensed state of DNA induced by spermine, and that the anomalous absorbance-temperature profile is due to the thermal stabilization of the tertiary structure of the spermine-induced collapsed state of the DNA.

INTERCALATING AGENTS의 핵산과의 상호작용에 미치는 폴리아민류의 영향에 대한 화학분광학적 연구 : 송아지 흉선 DNA-Spermine 복합체의 이례적 흡광도-온도 양상에 대한 Ethidium의 영향 Ⅰ. Ethidium Dependence of Spermine-Induced Anomalous Absorbance-Temperature Profile of Calf Thymus DNA

고동성,이천배,명평근 충남대학교 기초과학연구소 1984 연구논문집 Vol.5 No.-

Spectroscopic investigations of spermine effects on the ethidium-DNA binding equilibrium, and on the absorbance-temperature profile of the DNA in the presence of ethidium bromide at various concentrations were performed, as the ethidium binding may be used as the probe of the DNA interactions with environmental ligands. The cooperativity, enthalpy, and the midpoint of the phase transition to the trough region, of the anomalous absorbance-temperature profile, which occurs at the spermine concentration where the DNA collapses into a compact structure, are more sensitive to ethidium than the Tm region phase, and the trough can be eliminated by increased concentration of ethidium.

疎水性 環境이 Spermine에 의하여 誘發되는 凝縮된 DNA의 異例的 吸光度 : 溫度樣相에 미치는 影響 Temperature Profile of Condensed DNA, Induced by Spermine

高東成,李天培,崔宇永,李璨容 충남대학교 기초과학연구소 1986 연구논문집 Vol.6 No.-

We have investigated the effect of hydrophobic environmental reagents (urea and DMSO) on the anomalous absorbance-temperature profile of condensed DNA, induced by spermine. The cooperativity of the phase transition to the trough region in the anomalous absorbance-temperature profile is more sensitive to the hydrophobic environmental reagents than that of the melting region, and the trough peak size can be decreased by increased concentration of the hydrophobic reagents. The present data indicate the importance of hydrophobic interaction in the stabilization of the condensed state of DNA induced by spermine, and that the anomalous absorbance-temperature profile is due to the thermal stabilization of the tertiary structure of the spermine-induced collapsed state of the DNA.

스페르민-DNA 복합체의 이례적 흡광도-온도 양상에 미치는 DMSO의 영향

고동성,이천배,최우영,이찬용 충남대학교 기초과학연구소 1986 연구논문집 Vol.6 No.-

DNA의 응축을 유발시키는 spermine 농도 존재시 downward peak(trough)를 갖는 이례적 흡광도-온도 양상에 hydrophobic environment를 조성하는 DMSO의 영향을 조사하였다. DMSO 농도증가에 따라 downward peak의 깊이가 점차 얕아졌으며 그 phase transition enthalpy와 relative cooperative length(n)가 melting region보다는 downward peak(trough) phase transition에 더 예민하게 영향을 받았다. 따라서 본 data는 spermine에 의하여 유발되는 응축된 DNA 구조에 이르는 hydrophobic interaction에 의한 tertiary structure 형성이 온도상승에 따라 유리해짐으로써 downward peak가 형성된다는 추리를 확인하는 실험결과가 될 것이다. In an effort to improve our knowledge on the mechanism of the collapse of DNA into a compact structure by polyamines, we investigated the effect of dimethyl sulfoxide (DMSO), a hydrophobic environmental reagent on the anomalous absorbance-temperature profile of condensed DNA, induced by spermine and having a trough preceeded by the initiation of the melting phase. The trough peak size can be decreased by increased concentration of DMSO, and the cooperativity of the phase transition to the region in the anomalous absorbance-temperature profile is more sensitive to DMSO than that of the melting regions of the profile. The present data indicate that the anomalous absorbance-temperatuve profile is due to the thermal stabilization of the tertiary structure of the spermine-induced collapsed state of DNA and the importance of hydrophobic interaction in the stabilization of the condensed state of DNA induced by spermine.

p-Methoxystyrylphenylsulfone의 가수분해 반응메카니즘에 대한 반응속도론적 연구

權奇星,高東成,朴文奎,金演斗,成洛道 충남대학교 기초과학연구소 1981 연구논문집 Vol.2 No.-

The rate constants for the hydrolysis of p-methoxystyrylphenylsulfone were determined at wide pH ranges by means of UV spectrophotometer and the rate equations which could be applied to the experimental results were obtained. Form the facts, reaction mechanism was proposed : above pH 11.5, the rate is only dependent on the concentration of hydroxide ion and below pH 9.5, the reaction is initiated by the attack of a water molecule on the activated carbon-carbon double bond. In the range of pH from 9.5 to 11.5, these two reactions occur competitively.

RNase A에 對한 Spermine의 妨害效果로 부터 變性 DNA에 依한 救濟

李璨容,高東成 충남대학교 자연과학연구소 1983 忠南科學硏究誌 Vol.10 No.2

Recently we have reported that the susceptibility of denatured calf thymus DNA to DNase 1 is suppressed by spermine, while that of the native DNA is activated by spermine. We have also noted that the susceptibility of RNA to RNase A is suppressed by spermine, by being subjected to form inermolecular aggreates. In the present work, we find that the inhibitory effect of spermine on the susceptibility of RNA to RNase A can be relieved by the denatured DNA, but not by the native DNA. The possible explanation, based on our data, is that the relieving effec of the denatured DNA is brought about by RNA-DNA (denatured) interactions induced by spermine, thereby decreasing the aggregation of RNA molecules.