• Journal of the Korean Applied Science and Technology
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• v.29 no.3
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• pp.531-542
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• 2012

The thesis covers the trend of research on bio-based polyurethane which is made from polyols derived mainly from plant oils and isocyanates. Castor oil is a triglyceride of ricinoleic acid containing hydroxyl group. Hydroxylation is done on the unsaturated bonds of the oils by the reactions of epoxidation/ring opening, hydroformylation/hydrogenation, ozonolysis/hydrogenation, and thiol-ene reaction. Polyols from hyperbranch, primary alcohol, polysaccharide have been studied to control the reactivity of the polyol and morphology of the microdomains. Besides, researches cover biodegradable polylactic acid polyol for medical use, fatty acid dimer polyol for the prevention of hydrolysis, and polyol with ionic group for water-borne polyurethane. Bio-based polyurethanes are being used in flexible and rigid foams, coatings, sealants, and elastomers.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.3
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• pp.342-348
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• 2014

This study was conducted to examine the effects of condensed tannins (CT) from Ficus bengalensis leaves on the feed utilization, milk production and health status of crossbred cows. Eighteen crossbred dairy cows at their second and mid lactation (avg. BW $351.6{\pm}10.6$ kg) were randomly divided into two groups of nine each in a completely randomized block design and fed two iso-nitrogenous supplements formulated to contain 0% and 1.5% CT through dried and ground leaves of Ficus bengalensis. The diets were designated as CON and FBLM, respectively and fed to cows with a basal diet of rice straw to meet requirements for maintenance and milk production. The daily milk yield was significantly (p<0.05) increased due to supplementation of FBLM diet. The 4% fat corrected milk yield was also significantly (p<0.01) higher due to increased (p<0.05) milk fat in cows under diet FBLM as compared to CON. The inclusion of CT at 1.5% in the supplement did not interfere with the feed intake or digestibility of DM, OM, CP, EE, NDF, and ADF by lactating cows. Digestible crude protein (DCP) and total digestible nutrients (TDN) values of the composite diets were comparable between the groups. The blood biochemical parameters remained unaltered except significantly (p<0.05) lowered serum urea concentration in cows fed FBLM diet. There was a significant (p<0.05) increase intracellular reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) activity in cows supplemented with condensed tannins. The total thiol group (T-SH) was found to be higher with reduction in lipid peroxidation (LPO) in cows of FBLM group. The cost of feeding per kg milk production was also reduced due to supplementation of Ficus bengalensis leaves. Therefore, a perceptible positive impact was evident on milk production and antioxidant status in crossbred cows during mid-lactation given supplement containing 1.5% CT through Ficus bengalensis leaves.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.31-32
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• 2010

In our previous reports [1-3], electron transport for the switching and memory devices using alkyl thiol-tethered Ru-terpyridine complex compounds with metal-insulator-metal crossbar structure has been presented. On the other hand, among organic memory devices, a memory based on the OFET is attractive because of its nondestructive readout and single transistor applications. Several attempts at nonvolatile organic memories involve electrets, which are chargeable dielectrics. However, these devices still do not sufficiently satisfy the criteria demanded in order to compete with other types of memory devices, and the electrets are generally limited to polymer materials. Until now, there is no report on nonvolatile organic electrets using nano-interfaced organic monomer layer as a dielectric material even though the use of organic monomer materials become important for the development of molecularly interfaced memory and logic elements. Furthermore, to increase a retention time for the nonvolatile organic memory device as well as to understand an intrinsic memory property, a molecular design of the organic materials is also getting important issue. In this presentation, we report on the OFET memory device built on a silicon wafer and based on films of pentacene and a SiO2 gate insulator that are separated by organic molecules which act as a gate dielectric. We proposed push-pull organic molecules (PPOM) containing triarylamine asan electron donating group (EDG), thiophene as a spacer, and malononitrile as an electron withdrawing group (EWG). The PPOM were designed to control charge transport by differences of the dihedral angles induced by a steric hindrance effect of side chainswithin the molecules. Therefore, we expect that these PPOM with potential energy barrier can save the charges which are transported to the nano-interface between the semiconductor and organic molecules used as the dielectrics. Finally, we also expect that the charges can be contributed to the memory capacity of the memory OFET device.[4]

• Journal of Pharmacopuncture
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• v.22 no.3
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• pp.160-165
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• 2019

Objectives: The aim of this study was to evaluate the effect of Ribes khorasanicum (R. khorasanicum); a plant growing in north Khorasan of Iran; on cardiovascular and stress oxidative in acute hypertension induced by N-nitro-l-arginine methyl ester (L-NAME), anitric oxide synthase inhibitor. Methods: Rats were divided into Control, L-NAME (10 mg/kg), Sodium Nitroprusside (SNP) (50 mg/kg) + L-NAME and three treated groups with R. khorasanicum (4, 12 and 24 mg/kg) groups + L-NAME. L-NAME and SNP were injected intravenously and extract intraperitoneal. In R. khorasanicum groups, L-NAME was injected 30 min after injection of the extract. Systolic blood pressure (SBP), mean arterial pressure (MAP) and heart rate (HR) were recorded continuously using power lab software. At the end of study oxidative stress parameters including of total thiol content (SH), malondialdehyde (MDA), superoxide dismutase (SOD) and catalase (CAT) in heart and aorta of all groups were also measured. Results: In groups 4 and 24 mg/kg extract +L-NAME, there was a non-significant decrease in SBP and MAP compared to L-NAME group but dose 12 mg/kg significantly attenuate the effect of L-NAME(P < 0.05). In L-NAME group the heart and aorta tissues antioxidant enzymes levels decreased, while in treated rats these enzymes significantly increased. Conclusion: The extract of R. khorasanicum in dose 12 mg/kg show anti-hypertensive effect that is mediated by an effect on NO system or antioxidant parameters.

• Journal of Life Science
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• v.16 no.6
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• pp.1052-1059
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• 2006

The heat shock response is induced by environmental stress, pathophysiological state and non-stress conditions and wide spread from bacteria to human. Although translations of most proteins are stopped under a heat shock response, heat shock proteins (HSPs) are produced to protect cell from stress. When heat shock response is induced, conformation of HSF1 was changed from monomer to trimer and HSF1 specifically binds to DNA, which was called a heat shock element(HSE) within the promoter of the heat shock genes. Human HSF1(hHSFl) contains five cysteine(Cys) residues. A thiol group(R-SH) of Cys is a strong nucleophile, the most readily oxidized and nitrosylated in amino acid chain. This consideration suggests that Cys residues may regulate the change of conformation and the activity of hHSF1 through a redox-dependent thiol/disulfide exchange reaction. We want to construct role of five Cys residues of hHSF by redox reagents. According to two studies, Cys residues are related to trimer formation of hHSF1. In this study, we want to demonstrate the correlation between structural change and DNA-binding activity of HSF1 through forming disulfide bond and trimerization. In this results, we could deduce that DNA binding activity of DNA binding domain wasn't affected by redox for always expose outside to easily bind to DNA. DNA binding activity of wild-type HSF's DNA binding domain was affected by conformational change, as conformational structure change (trimerization) caused DNA binding domain.

• Archives of Pharmacal Research
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• v.21 no.6
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• pp.683-687
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• 1998

We have examined in vitro and in vivo radioprotective effects of a well-known thiol-containing compound, dithiothreitol (DTT). The treatment of both 0.5 and 1mM of DTT significantly increased clonogenic survival of ${\gamma}$-ray irradiated Chinese hamster (V79-4) cells. In order to investigate the possible radioprotective mechanism of DTT, we measured gamma-ray induced chromosome aberration by micronucleus assay. In the presence of 0.5mM or 1mM DTT, the frequencies of micronuclei were greatly reduced in all dose range examined (1.5-8 GY). Slightly higher reduction in micronucleus formation was observed in 1mM DTT-treated cells than in 0.5mM DTT-treated cells. In addition, incubation with both 0.5 and 1mM of DTT prior to gamma-ray irradiation reduced nucleosomal DNA fragmentation at about same extent, this result suggests that treatment of DTT at concentrations of 0.5 and 1mM reduced radiation-induced apoptosis. In vivo experiments, we also observed that DTT treatment reduced the incidence of apoptotic cells in mouse small intestine crypts. In irradiated control group 4.4${\pm}$0.5 apoptotic cells per crypt were observed. In DTT-administered and irradiated mice, only 2.1${\pm}$0.4 apoptotic cells per crypt was observed. In vitro and in vivo data obtained in this study showed that DTT reduced radiation-induced damages and it seems that the possible radioprotective mechanisms of action of DTT are prevention of chromosome aberration.

• Archives of Pharmacal Research
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• v.25 no.6
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• pp.801-806
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• 2002

Cyclicpeptides are important targets in peptide synthesis because of their interesting biological properties. Constraining highly flexible linear peptides by cyclization is one of the mostly widely used approaches to define the bioactive conformation of peptides. Cyclic peptides often have increased receptor affinity and metabolic stability over their linear counterparts. We carried out virtual screening experiment via docking in order to understand the interaction between HLE-Human Leukocyte Elastase and ligand peptide and to identify the sequence that can be a target in various ligand peptides. We made cyclic peptides as a target base on Metlle-Phe sequence having affinity for ligand and receptor active site docking. There are three ways to cyclize certain sequences of amino acids such as Met-lie-Phe-Gly-Ile. First is head-to-tail cyclization method, linking between N-terminal and C-terminal. Second method utilizes amino acid side chain such as thiol functional group in Cys, making a thioether bond. The last one includes an application of resin-substituted amino acids in solid phase reaction. Among the three methods, solid phase reaction showed the greatest yield. Macrocyclization of Fmoc-Met-Ile-Phe-Gly-Ile-OBn after cleavage of Fmoc protection in solution phase was carried out to give macrocyclic compound 5 in about 7% yield. In the contrast with solution phase reaction, solid phase reaction for macrocyclization of Met-Ile-Phe-Gly-Ile-Asp-Tentagel in normal concentrated condition gave macrocyclic compound 7 in more than 35% yield.

• BMB Reports
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• v.32 no.4
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• pp.414-418
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• 1999

A novel gene for malonyl-CoA decarboxylase was discovered in the mat operon, which encodes a set of genes involved in the malonate metabolism of Rhizobium trifolii (An and Kim, 1998). The subunit mass determined by SDS-PAGE was 53 kDa, which correspond to the deduced mass from the sequence data. The molecular mass of the native enzyme determined by field flow fractionation was 208 kDa, indicating that R. trifolii malonyl-CoA decarboxylase is homotetrameric. R. trifolii malonyl-CoA decarboxylase converted malonyl-CoA to acetyl-CoA with a specific activity of 100 unit/mg protein. Methylmalonyl-CoA was decarboxylated with a specific activity of 0.1 unit/mg protein. p-Chloromercuribenzoate inhibited this enzyme activity, suggesting that thiol group(s) is(are) essential for this enzyme catalysis. Database analysis showed that malonyl-CoA decarboxylase from R. trifolii shared 32.7% and 28.1% identity in amino acid sequence with those from goose and human, respectively, and it would be located in the cytoplasm. However, there is no sequence homology between this enzyme and that from Saccharopolyspora erythreus, suggesting that malonyl-CoA decarboxylases from human, goose, and R. trifolii are in the same class, whereas that from S. erythreus is in a different class or even a different enzyme, methylmalonyl-CoA decarboxylase. According to the homology analysis, Cys-214 among three cysteine residues in the enzyme was found in the homologous region, suggesting that the cysteine was located at or near the active site and plays a critical role in catalysis.

• BMB Reports
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• v.30 no.6
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• pp.397-402
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• 1997

A thiol-specific spin label was attached to cysteine-102 of yeast cytochrome c and electron paramagnetic resonance (EPR) spectra were measured as a function of added cytochrome c oxidase concentration. The intensity decreased due to line broadening as cytochrome c formed a complex with cytochrome c oxidase and reached a minimum when the ratio of cytochrome c to cytochrome c oxidase became one. Replacement of either Lys-72 or Lys-87 of cytochrome c by Glu did not result in a significant change in binding affinity. Interestingly the K72E mutant, unlike K87E, had a much lower rate of electron transfer than the wild type. These results indicate that many positively charged residues as a group participate in complex formation but Lys-72 might be important for cytochrome c to be locked in an orientation for an efficient electron transfer. A stoichiometry of 1 was also confirmed by optical absorption of the cytochrome c-cytochrome c oxidase complex which had been run through a gel chromatography cloumn to remove unbound cytochrome c. The EPR spectrum of this 1:1 complex, however, was a mixture of two components. This explains a biphasic kinetics for a single binding site on cytochrome c oxidase without invoking conformational transition.

• International Journal of Oral Biology
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• v.33 no.3
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• pp.117-123
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• 2008

Reactive oxygen species (ROS) are toxic agents that may be involved in various neurodegenerative diseases. Recent studies indicate that ROS can act as modulators of neuronal activity, and are critically involved in persistent pain primarily through spinal mechanisms. In the present study, whole cell patch clamp recordings were carried out to investigate the effects of tert-buthyl hydroperoxide (t-BuOOH), an ROS, on neuronal excitability and the mechanisms underlying changes of membrane excitability. In current clamp condition, application of t-BuOOH caused a reversible membrane depolarization and firing activity in substantia gelatinosa (SG) neurons. When slices were pretreated with phenyl-N-tert-buthylnitrone (PBN) and ascorbate, ROS scavengers, t-BuOOH failed to induce membrane depolarization. However, isoascorbate did not prevent t-BuOOH-induced depolarization, suggesting that the site of ROS action is intracellular. The t-BuOOH-induced depolarization was not blocked by pretreatment with dithiothreitol (DTT), a sulfhydryl-reducing agent. The membrane-impermeant thiol oxidant 5,5-dithiobis 2-nitrobenzoic acid (DTNB) failed to induce membrane depolarization, suggesting that the changes of neuronal excitability by t-BuOOH are not caused by the modification of extrathiol group. The t-BuOOH-induced depolarization was suppressed by the phospholipase C (PLC) blocker U-73122 and inositol triphosphate ($IP_3$) receptor antagonist 2-aminoethoxydiphenylbolate (APB), and after depletion of intracellular $Ca^{2+}$ pool by thapsigargin. These data suggest that ROS generated by peripheral nerve injury can induce central sensitization in spinal cord, and t-BuOOH-induced depolarization may be regulated by intracellular $Ca^{2+}$ store mainly via $PLC-IP_3$ pathway.