• Development and Reproduction
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• v.21 no.4
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• pp.417-424
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• 2017

Alzheimer's disease (AD) is neurodegenerative disease, characterized by the progressive decline of memory, cognitive functions, and changes in personality. The major pathological features in postmortem brains are neurofibrillary tangles and amyloid beta ($A{\beta}$) deposits. The majority of AD cases are sporadic and age-related. Although AD pathogenesis has not been established, aging and declining mitochondrial function has been associated. Mitochondrial dysfunction has been observed in AD patients' brains and AD mice models, and the mice with a genetic defect in mitochondrial complex I showed enhanced $A{\beta}$ level in vivo. To elucidate the role of mitochondrial complex I in AD, we used SH-SY5Y cells transfected with DNA constructs expressing human amyloid precursor protein (APP) or human Swedish APP mutant (APP-swe). The expression of APP-swe increased the level of $A{\beta}$ protein in comparison with control. When complex I was inhibited by rotenone, the increase of ROS level was remarkably higher in the cells overexpressing APP-swe compared to control. The number of dead cell was significantly increased in APP-swe-expressing cells by complex I inhibition. We suggest that complex I dysfunction accelerate amyloid toxicity and mitochondrial complex I dysfunction in aging may contribute to the pathogenesis of sporadic AD.

• Journal of the Korean Chemical Society
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• v.18 no.3
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• pp.202-209
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• 1974

Polarographic behaviors of copper and cadmium complexes with 2,2'-bipyridine and ethylenediamine in acetonitrile have been investigated by the DC and AC polarography. The reduction processes are estimated as follows; $Cu(II)-bipy. \;complex\;{\longrightarrow^{e^-}_{E_{1/2}\risingdotseq+0.1V}}\;Cu(I)-bipy.\;complex\;{\longrightarrow^{e^-}_{E_{1/2}=-0.43V}}\;Cu(Hg)$$Cu(II)-en.\;complex\;{\longrightarrow^{e^-}}\;Cu(I)-en.\;complex\;{times}\;{\longrightarrow^{e^-}_{E_{1/2}=-0.56V}}\;Cu(Hg)$$Cu(II)-bipy. \;complex\;{\longrightarrow^{e^-}_{E_{1/2}=-0.57V}}\;Cu(I)-bipy.\;complex\;{\longrightarrow^{2e^-}_{E_{1/2}=-0.97V}}\;Cd(I)-bipy\;complex$$Cu(II)-en.\;complex\;{\longrightarrow^{e^-}_{E_{1/2}=+0.05V}\;Cu(I)-en.\;complex{\longrightarrow^{e^-}_{E_{1/2}=-0.92V}}\;Cu(Hg)$ The limiting currents of all steps are controlled by diffusion. The number of ligand and the dissociation constant for Cu(Ⅰ)-bipy. complex were found to be n = 2 and $K_d=(1.5{\pm}0.1){\times}10^{-7}$, respectively.

• Journal of the Korean Chemical Society
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• v.29 no.1
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• pp.9-14
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• 1985

The solubilities of i-propyl bromide in nitrobenzene have been measured at 10$^{\circ}$, 19$^{\circ}$ and 25$^{\circ}C$ in the presence and absence of gallium bromide. In the presence of gallium bromide, 1 : 1 complex, i-C$_3$H$_7Br{\cdot}GaBr_3$ is formed in the solution. The instability constant K of the complex formation was evaluated from the following equilibrium equation: i-C$_3$H$_7Br{\cdot}GaBr_3$ ${\rightleftharpoons}$ i-C$_3$H$_7$Br + $\frac{1}{2}$$Ga_2Br_6$. The change of enthalpy, free energy and entropy for the dissociation of the complex were also calculated. From these result, it seems that the stabilities of the complex formation, gallium bromide with alkyl bromide, are directly related with those of the carbonium ions of alkyl bromide.

• Molecules and Cells
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• v.25 no.2
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• pp.158-162
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• 2008

Recent molecular genetics studies have revealed that cyclic electron transport around photosystem I is essential for normal photosynthesis and growth of plants. Chloroplastic NAD(P)H dehydorgenase (NDH) complex, a homologue of the complex I in respiratory electron transport, is involved in one of two cyclic pathways. Recent studies on the function and structure of the NDH complex are reviewed.

• Journal of the Korean Society of Systems Engineering
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• v.2 no.1
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• pp.37-41
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• 2006

The KSLV-I satellite launch vehicle will be launched in a space center currently under construction. The Space Center which is an advance post base of space development of Korea is located on Oenaro island in Kohung, South Cholla Province. A Ground Complex of the Space Center consists of an AC(Assembly Complex), a LC(Launch Complex), and a MCC(Mission Control Center). Assembly and test facilities are located in the AC in which stage assembly, integrated assembly, check-up, certification test, and pre-launch test are made effectively. A launch pad, fuel supply facilities, a launch control center and associated supporting facilities are located in the LC, and the MCC has control over the space center. These ground complex facilities have diverse forms of an interface with mechanical device, electric device, and etc. These should also provide optimum condition and performance during launch operation processes of the launch vehicle. This paper introduces the result of R&D for the AC of the ground complex performed during system design period.

• Journal of Plant Biology
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• v.26 no.2
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• pp.91-99
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• 1983

The formation of chlorophyll-protein complexes (CP-complexes) during the greening of rape cotyledons (Brassica napus cv. Yongdang) was investigated by the SDS-polyacrylamide gel electrophoresis. The total chlorophyll content and Chl a/b ratio were also determined. In addition, the effects of dark treatment on the CP-complex patterns during greening have been examined with respect to their photosynthetic electron transport activity. Greening has brought about the increasein total chlorophyll content and the decrease in Chl a/b ratio, but there have been no changes in Chl a/b ratio after 24 hrs of greening. The light-harvesting chlorophyll a/b-protein complex (LHCP-complex0 was predominant during the initial greening period. Thereafter, the amout of chlorophyll a-protein complex (CP I-complex) was gradually increased. Twenty-four-hr dark treatment immediately after illumination for 6 hrs and 12 hrs resulted in the increase of the Chl a/b ration and the CP I complex, otherwise the decrease of the LHCP-complex. The LHCP/CP I ratio was gradually decreased with further greening, and appeared no change after 48 hrs illumination. The investigation of the photosynthetic electron transport activity indicated that photosystem (PS) II activity (H2Olongrightarrowp-PD*＋FeCy**) did not change, but the activity of PS I was increased suddenly due to the dark treatment. The data suggests that the increase of CP I-complex may result in that of P-700, that is, the increase of PS I activity.

• Journal of the Korean Chemical Society
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• v.30 no.1
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• pp.51-56
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• 1986

Polarographic behavior of cadmium(II) and copper (II) complexes of 1,5-diphenylcarbohydrazide in dimethylsulfoxide have been investigated by the DC polarography. The reduction processes are estimated as follows; Cd(II)${\cdot}$DPH Complex$\frac{e^-}{(E_{\frac{1}{2}}=-0.12V)}$${\to}$Cd(I)${\cdot}$DPH Complex. Cd(I)${\cdot}$DPH Complex$\frac{e^-}{(E_{\frac{1}{2}}=-0.74V)}$${\to}$Cd(Hg) + nDPH. Cu(II)${\cdot}$DPH Complex$\frac{e^-}{(E_{\frac{1}{2}}=-0.44V)}$${\to}$Cu(I)${\cdot}$DPH Complex. Cu(I)${\cdot}$DPH Complex$\frac{e^-}{(E_{\frac{1}{2}}=-0.84V)}$${\to}$Cu(Hg) + nDPH. The limiting currents of all reduction wave are irreversible. The number of ligand and the dissociation constant for Cu(I)${\cdot}$1.5-diphenylcarbohydrazide complex were found to be 2 and 5.12 ${\times}10^{-8}$, respectively. All reduction waves of complexes are irreversible. Based on the experimental results, the polarographic reductions of complexes in dimethylsulfoxide solution occurred in two one-electron steps.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1863-1866
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• 2002

This paper describes synthesis of a complex R$^{i}$ CR filter with a finite transmission zero except zero frequency. First, a new kernel function is proposed. Secondly, how to determine the element values included in the R$^{i}$ CR filter is described. A fifth-order R$^{i}$ CR filter is designed. Finally, the sensitivity property of the proposed filter is evaluated through computer simulation.

• Journal of the Korean Magnetic Resonance Society
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• v.8 no.2
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• pp.86-95
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• 2004

A Cu(I) complex with an asymmetric TTF derivative (CET-EDTTTF) is prepared from the slow-diffusion method using CET-EDTTTF and Cu(I)Br solutions and characterized by X-ray crystallography and EPR spectroscopy. Structural analysis shows Cu(I) ions are tetrahedrally coordinated to two bridging bromides, one terminal bromide, and one S atom from CET-EDTTTF. Detailed geometrical and EPR analysis identified that the dimmer molecule contains [Cu$_2Br_4]^{2-}$ anion between two [CET-EDTTTF]$^+$ radical cations. Single-crystal EPR investigation of the complex reveals that the ganisotropy is unusually big, compared to those of the previously reported TTF+ cation radicals, implying that there is significant contribution of the Cu d-orbital to the HOMO of the complex.

• Archives of Pharmacal Research
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• v.27 no.6
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• pp.670-675
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• 2004

Since the bitter taste of enrofloxacin apparently limit the patient compliance in the oral formulations of the antibacterial agent, the masking of the taste is essential for the improvement of the therapeutic effectiveness. Therefore, this study was carried out to examine the feasibility of taste masking of enrofloxacin by the retardation of its dissolution rate using the formation of complex between the drug and Carbopol. The complexation between Carbopol and enrofloxacin was confirmed by turbidity, UV spectrophotometry, wide angle X-ray diffraction, and differential scanning calorimetry. The enrofloxacin content in the complexes was 34％ （Carbo-enrofloxacin complex I） and 57％ （Carbo-enrofloxacin complex II） depending on the prepara-tion method. The dissolution rate of enrofloxacin from the complex increased as the pH was reduced. The dissolution rate of enrofloxacin from the Carbo-enrofloxacin complex I was significantly lower than that of the enrofloxacin powder. Therefore, these observations suggest that Carbo-enrofloxacin complex I can be used to mask the taste of enrofloxacin.