• BMB Reports
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• 제39권4호
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• pp.452-456
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• 2006

To elaborate the peroxidase activity of cytochrome c in the generation of free radicals from $H_2O_2$, the mechanism of DNA cleavage mediated by the cytochrome c/$H_2O_2$ system was investigated. When plasmid DNA was incubated with cytochrome c and $H_2O_2$, the cleavage of DNA was proportional to the cytochrome c and $H_2O_2$ concentrations. Radical scavengers, such as azide, mannitol, and ethanol, significantly inhibited the cytochrome c/$H_2O_2$ system-mediated DNA cleavage. These results indicated that free radicals might participate in the DNA cleavage by the cytochrome c and $H_2O_2$ system. Incubation of cytochrome c with $H_2O_2$ resulted in a time-dependent release of iron ions from the cytochrome c molecule. During the incubation of deoxyribose with cytochrome c and $H_2O_2$, the damage to deoxyribose increased in a time-dependent manner, suggesting that the released iron ions may participate in a Fenton-like reaction to produce $\cdot$OH radicals that may cause the DNA cleavage. Evidence that the iron-specific chelator, desferoxamine (DFX), prevented the DNA cleavage induced by the cytochrome c/$H_2O_2$ system supports this mechanism. Thus we suggest that DNA cleavage is mediated via the generation of $\cdot$OH by a combination of the peroxidase reaction of cytochrome c and the Fenton-like reaction of free iron ions released from oxidatively damaged cytochrome c in the cytochrome c/$H_2O_2$ system.

• Parasites, Hosts and Diseases
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• 제36권2호
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• pp.109-120
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• 1998

서울주걱흡충 (Weodiplostomum seoulense)에 감염된 BALB/c 및 C3H 마우스의 소장에서 비만 세포 및 배세포 반응 양상을 관찰하고, 이들 반응이 숙주 방어기전 및 충체 배출에 영향을 줄 수 있는지 알아보았다. 마우스 1마리당 피낭유충 200개씩을 감염시킨 후 28일까지 충체회수율을 관 찰한 바 BALB/c 마우스가 C3H 마우스에 비해 월등히 높은 충체회수율을 보였다 그러나, 마우스 주에 관계없이 충체의 주 기생부위인 십이지장에서 감염 7일에 비만세포수가 최고에 달하였고 곧 바로 감소하였다. 이러한 비만세포수의 반응 양상은 공장 및 회장에서도 비슷하게 나타났으며, 반응의 강도는 십이지장이나 공장이 회장에 비해 높았다. 또한, 비만세포수의 최고치는 BALB/c 마우스에서 C3H 마우스보다 오히려 높게 나타났다. 배세포 증식은 BALB/c 마우스의 경우 감염 14 일을 제외하고는 십이지장에서 뚜렷이 관찰되었고, C3H 마우스의 경우에는 감염 7일에 공장 및 회장에서 관찰되었다. 배세포의 점액 (mucin) 활성은 BAkBlc 및 C3H 마우스 모두에서 인정되었으나, 그 강도는 BALBlc 마우스에서 더욱 뚜렷하였다. 이상의 결과를 종합할 때, 이들 마우스의 장점막 비만세포 및 배세포 반응은 서울주걱흡충 감염에 대한 국소적인 면역반응으로 나타나지만 숙주 방어나 충체 배출에의 관여도는 낮을 것으로 추측되었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.89-90
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• 2007

This paper presents the mechanical properties of 3C-SiC thin film according to 0, 7, and 10% carrier gas $(H_2)$ concentrations using Nano Indentation. When carrier gas $(H_2)$ concentration was 10%, it has been proved that the mechanical properties, elastic modulus and hardness, of 3C-SiC are the best of them. In the case of 10% carrier gas concentration, Young's modulus and Hardness were obtained as 367 GPa and 36 GPa, respectively. When the surface roughness according to $H_2$ concentrations was investigated by AFM (atomic force microscope), when $H_2$ concentration was 10%, the roughness of 3C-SiC thin was 9.92 nm, which is also the best of them. Therefore, in order to apply poly 3C-SiC thin film to MEMS applications, $H_2$ concentration's rate should increase to obtain better mechanical properties and surface roughness.

• 전기전자학회논문지
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• 제18권4호
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• pp.620-624
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• 2014

본 연구에서는, Ni/CNT/$SiO_2$ 구조의 4H-SiC MIS 캐패시터를 제작하고 전기적 특성을 조사하였다. 이를 통하여 4H-SiC MIS 소자에서 탄소나노튜브의 역할을 분석하고자 하였다. 탄소나노튜브는 이소프로필알코올과 혼합하여 $SiO_2$ 표면에 분산하였다. 소자의 전기적 특성 분석을 위하여 300-500K의 온도 범위에서 소자의 정전용량-전압 특성을 측정하였다. 밴드 평탄화 전압은 양의 방향으로 shift되었다. 정전용량-전압 그래프로부터 계면 포획 전하 밀도 및 산화막 포획 전하 밀도가 유도되었다. 산화막의 상태는 4H-SiC MIS 구조의 계면에서 전하 반송자 또는 결함 상태와 관련된다. 온도가 증가함에 따라 밴드 평탄화 전압은 음의 방향으로 shift되는 결과를 얻었다. 실험 결과로부터, Ni과 $SiO_2$ 계면에 탄소나노튜브를 첨가함에 따라 4H-SiC MIS 캐패시터의 게이트 특성을 조절 가능할 것으로 판단된다.

• 대한화학회지
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• 제35권4호
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• pp.368-373
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• 1991

isonitrosoethylacetoacetate(H-IEAA)의 이민유도체를 리간드로 하는 새로운 Pd(II) 착물, Pd(IEAA-NR)$_2$(R = H, CH$_3$, C$_2$H$_5$, n-C$_3$H$_7$, n-C$_4$H$_9$ 또는 CH$_2$C$_6$H$_5$)를 합성하고, 이들의 구조를 원소분석, 전자 흡수분광법, 적외선흡수분광법, $^1$H 및 $^{13}$C 핵자기공명 분광법으로 조사하였다. 그 결과 이들 Pd(Ⅱ) 착물은 모두 사각평면구조를 가지며, 착물에서 두 IEAA-NR 리간드가 모두 이민 질소와 N-O의 질소를 통하여 금속에 배위되어 5원 고리를 이루고 있음을 알 수 있었다.

• 대한화학회지
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• 제16권2호
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• pp.59-63
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• 1972

In connection with two electron binding energy of each bond of saturated hydrocarbons, C-C bond fission and hydrogen abstraction from C-H bond are discussed by means of two center Huckel method. A beautiful correlation could be noticed between the observed bond dissociation energy and the calculated bond energy except for n-butane. Bond dissociation energies between C-C bond were also related to C-C bond fission. We could also find a very close relation between the relative easiness of hydrogen abstraction and the calculated binding energy of C-H bond. In other words, C-H bonds of tertiary hydrogen have been noticed as most weakely bonded and hence the tertiary hydrogen would most easily from the paraffins. In addition, the C-H binding energy is discussed applying ionic character of C-H bond which is derived from its dipole moment (0.4D)

• Bulletin of the Korean Chemical Society
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• 제27권6호
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• pp.830-834
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• 2006

Lipid peroxidation induced by the reaction of cytochrome c with $H_2O_2$ was investigated. When linoleic acid micelles or phosphatidyl choline liposomes were incubated with cytochrome c and $H_2O_2$, lipid peroxidation was increased in cytochrome c and $H_2O_2$ concentrations-dependent manner. Radical scavengers, azide, formate and ethanol prevented lipid peroxidation induced by the cytochrome c/$H_2O_2$ system. Iron specific chelator, desferoxamine also prevented the cytochrome c/$H_2O_2$ system-mediated lipid peroxidation. These results suggest that lipid peroxidation may be induced by the cytochrome c/$H_2O_2$ system via the generation of free radicals. Carnosine, homocarnosine and anserine are present in the muscle and brain of many animals and human. Previous studies show that these compounds have an antioxidant function. In the present study, carnosine, homocarnosine and anserine significantly prevented the cytochrome c/$H_2O_2$ system-mediated lipid peroxidation. Carnosine and related compounds also inhibited the free radical-generating activity of cytochrome c. The results suggest that carnosine, homocarnosine and anserine may prevent lipid peroxidation induced by the cytochrome c/$H_2O_2$ system through a free radical scavenging.

• 대한화학회지
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• 제56권4호
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• pp.440-447
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• 2012

Heteroleptic complexes of zirconium (IV) derived from bulky Schiff base ligands containing a sulphur atom and oximes of heterocyclic ${\beta}$-diketones of the general formula ZrLL' (where $LH_2=RCNH(C_6H_4)SC:C(OH)N(C_6H_5)N:CCH_3$, $R=-C_6H_5$, $-C_6H_4Cl(p)$ and $L^{\prime}H_2=R^{\prime}C:(NOH)C:C(OH)N(C_6H_5)N:CCH_3$, $R^{\prime}=-CH_2CH_3$, $-C_6H_5$, $-C_6H_4Cl(p)$ were prepared by the reactions of zirconium tetrachloride with disodium salts of Schiff bases ($L\;Na_2$) and oximes of heterocyclic ${\beta}$-diketones ($L^{\prime}\;Na_2$) in 1:1:1 molar ratio in dry refluxing THF. The structures of these monomeric zirconium (IV) complexes were elucidated with the help of elemental analysis, molecular weight measurements, spectroscopic (IR, NMR and mass) studies. A distorted trigonal bipyramidal geometry may be suggested for these heteroleptic zirconium (IV) complexes. The ligands (bulky Schiff base ligands containing a sulphur atom and oximes of heterocyclic ${\beta}$-diketones) and their heteroleptic complexes of zirconium (IV) were screened against A. flavus, P. aeruginesa and E. coli.

• Transactions on Electrical and Electronic Materials
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• 제12권3호
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• pp.89-92
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• 2011

Hydrogenated amorphous carbon (a-C:H) films were deposited by plasma enhanced chemical vapor deposition on silicon substrates. a-C:H thin film was irradiated to a typical He-Cd laser to study its emitting properties. The photoluminescence (PL) intensity during the irradiation achieved a maximum value when 2,000 seconds elapsed. Fourier transform infrared measurement revealed a-C:H thin film suffered transformation from a polymer-like to graphite-like phase during laser irradiation. Thermal annealing was done at various temperatures, ranging from room temperature to $400^{\circ}C$ in the atmosphere, to investigate structural changes in a-C:H film by heat generation during the emission. PL intensity of a-C:H thin film increased 1.5 times without apparent structural change, as annealing temperature increased up to $200^{\circ}C$. However, a-C:H film above $200^{\circ}C$ exhibited significant decrease of PL accompanying dehydrogenation. This led to a red shift of the PL peak.

• Journal of Pharmaceutical Investigation
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• 제36권4호
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• pp.283-286
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• 2006

The present study aimed to investigate the interaction of nucleoside analogs with human organic anion transporter 1 and 3(hOAT1 and hOAT3) that play a primary role in the tubular uptake of endogenous and exogenous organic anions in the kidney. The interactions of ddC, ara-C, ara-A and ara-U with hOAT1 and hOAT3 were examined using MDCK cells stably overexpressing hOAT1 or hOAT3. Among the tested drugs, ddC showed the highest affinity to hOAT1 with $IC_{50}$ values of 5.2 mM, while ara-A, ara-C and ara-U weakly inhibited the cellular uptake of $[^3H]-PAH$ in MDCK-hOAT1 cells at 1 mM. In contrast, all the tested drugs did not have any inhibition effect on the cellular uptake of $[^3H]-estrone$ sulfate in MDCK-hOAT3 cells over the drug concentration of 0.01-2 mM, implying that they might not interact with hOAT3. Taken all together, the present study suggests that hOAT1 could weakly interact with nucleoside analogues such as ddC, ara-C, ara-A and ara-U but the interaction with hOAT3 during the urinary excretion of these nucleoside analogues may be negligible in the kidney.