• Applied Chemistry for Engineering
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• v.7 no.5
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• pp.861-868
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• 1996

Skeletal isomerization reaction known as exothermic reaction shows possible maximum yield of i-butene from n-butene at $110^{\circ}C$ over $Pt/MoO_3/SiO_2$. Compared with conventional catalyst such as silica, zeolite, alumina etc., $Pt/MoO_3/SiO_2$ demonstrates higher yield while by-products except 2-butene do not form. Faster H spillover rate over $Pt/MoO_3/SiO_2$ is demonstrated via isothermal reduction experiment at $110^{\circ}C$ compared to the rate over $Pt/MoO_3/Al_2O_3$. Overall isomerization rates are proportional to higher spillover rates from Pt onto $MoO_3$ surface. The skeletal isomerization reaction is composed of two elementary steps. First, carbonium ion formation over Pt crystallites by H spillover. Second, carbenium ion formation over $MoO_3$ followed by formation of i-butene. Moreover, it is suggested that H spillover step from Pt surface onto $MoO_3$ is assumed to be the rate determining step and control the overall isomerization rate.

• Korean Journal of Animal Reproduction
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• v.19 no.4
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• pp.307-322
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• 1996

The corpus luteum (CL) is formed by the action of a surge of luteinizing hormone (LH) on the pre-ovulatory follicle. Luteal cells derived from granulosa and theca interna cells continue to secrete progesterone for about two weeks. LH in domestic animals is essential for the normal secretion of progesterone at all stages of the luteal phase. For this process in the rodents, 20$\alpha$-hydroxysteroid dehydrogenase (20$\alpha$-HSD) is indispensable. 20$\alpha$-HSD is an enzyme to be a biologically inactive steroid. This enzyme plays a critical role in the regulation of the rat luteal function and reported to be present in steroid-producing tissues such as the testis and adrenal gland. We have purified 20$\alpha$-HSD and found two distinct 20$\alpha$-HSD molecules (HSD-1 and HSD-2). Their molecular weights are both estimated to be 33kd.The amino acid compositions of HSD-1 and HSD-2 are mostly similar, but there is a slight difference in the content of lysine. We demonstrated that 1) CL of previous generations contribute more to whole ovarian 20$\alpha$-HSD activity, 2) newly formed corpora lutea contain only 20$\alpha$-HSD-1 activity, and 3) old CL express activities of each HSD isozyme as shown in the luteal tissue of cycling rats on the day of diestrus where only degenerating old CL exist. The increase in 20$\alpha$-HSD activity identified seems to be related to the increase in the numbers of 20$\alpha$-HSD-positive cells. Interestingly, 20$\alpha$-HSD-1 activities were strongly found in the follicle fluids and theca interna cells by immunohistochemical study. Thus, the activity of 20$\alpha$-HSD may be related to a survival mechanism of those luteal cells and follicles remaining in the ovaries. Luteal cells arise from two sources. The small luteal cells are all of theca cell origin, while the large luteal cells are mainly of granulosa cell origin. CL of Korean Native Cattle, as those of other animal species, contains two morphologycally and functionally distinct luteal cell populations, such as small and large luteal cells as well as nonluteal cells. In all reproductive states except in the late luteal phase, the bovine CL also contained more small luteal cells than large luteal cells. Luteal tissue secretes a variety of growth factors (proteins) and the pattern of secretion changes during all stages of the luteal phase. These growth factors could be important in regulating the function of the bovine corpus luteum and may act in a potential endocrine autocrine and paracrine mechanisms. Therefore, further work has to be done to elucidate the role of growth factors in the ovary, especially in the corpus luterum. Interest should be focussed on interaction of these growth factors in the regulation of luteal cell and the localization of cytokine synthesis in differnet luteal cells.

• Korean Security Journal
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• no.50
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• pp.11-32
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• 2017

The Civil Contingencies Act 2004 in the United Kingdom provides a comprehensive definition of "Emergency", calling upon the Uk's emergency management to deal with any disaster risk regardless of cause or source. Old contingency plans for civil defense and peacetime emergencies have been integrated into current integrated emergency management. In the UK, emergencies are managed by emergency services and other responders at the local level without direct involvement of central government. On top of this, a classified assessment of the risks of civil emergencies is also conducted on a regular basis, not only at the local level but also at the national level. This research looks into the Uk's emergency management system, including recent changes, and its risk assessment systems. Finally, the research draws policy implications for the development of Korea's disaster management mechanism as follows: 1) Korea should adopt an integrated emergency management system and combine civil defense with peacetime emergency planning, 2) it should create inter-operability between emergency responding organizations such as police, fire and ambulance, and finally 3) it must develop risk evaluating tools, such as a Community Risk Register and National Risk Register, both at the local and the national level. Last but not least, the UK emergency management system cannot be directly lifted from the UK and applied to risks and hazards faced by South Korea. Therefore, cross-cultural synthesis of many national approaches to emergency management is further required particularly for customizing policy to the particular needs of Korea.

• Korean Journal of Veterinary Research
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• v.41 no.3
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• pp.299-304
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• 2001

The effect of the nitric oxide synthase(NOS) inhibitor, $N^{G}$-nitro-L-arginine methyl ester (L-NAME), and the prostanoid synthesis inhibitor, indomethacin, on the vasodilatation produced in response to acetylcholine(Ach) on the isolated rabbit renal artery was examined. The vasodilatory reponses to Ach($10^{-8}-3{\times}10^{-5}M$) were completely absent in thevessel which the endothelium had previous been removed. L-NAME($10^{-4}M$) significantly reduced the vasodilatory reponse to the Ach($10^{-8}-3{\times}10^{-5}M$). When L-arginine ($10^{-3}M$) was also present in the organ bath along with L-NAME($10^{-4}M$), this inhibitory effect of L-NAME ($10^{-4}M$) on the vasodilatory response to Ach ($10^{-8}-3{\times}10^{-5}M$) was significantly attenuated, Indomethacin ($10^{-6}M$) did not significantly affect the vasodilatory responses to Ach ($10^{-8}-3{\times}10^{-5}M$). The inhibition by L-NAME ($10^{-4}M$) and indomethacin ($10^{-6}M$) on vasodilatory response to Ach was significantly greater than the inhibition due to L-NAME ($10^{-4}M$) alone. The present study has established that Ach induce relaxation via and endothelium-dependent mechanism, this relaxation to Ach involves both nitric oxide(NO) and prostanoid in the isolated rabbit renal artery.

• Journal of the Korean Wood Science and Technology
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• v.34 no.3
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• pp.56-63
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• 2006

In order to evaluate the mechanism of cellulose hydrolysis, the complementary DNA encoding Glycoside Hydrolase Family (GHF)74 was cloned from Phanerochaete chrysosporium. Depending on the presence of Cellulose Binding Module (CBM), it can be classified as GHF74A or GHF74B. The GHF74A gene from P. chrysosporium (PcGHF74A) consists of 2163 bp encoding a protein of 721 amino acid residues. The PcGHF74A showed homology of 70~77% compared with the GHF74 from other filamentous fungi. The PcGHF74B, which contains CBM and is a member of family 1, was transcribed to various transcripts depending on the nature of carbon sources and their concentration. To study the possible presence of splice variants in GHF74B transcripts in P. chrysospoium, we carried out RT-PCR analysis using primers that designed based on the annotation data and sequenced data. Our result indicated that PcGHF74B was transcribed to several splicing variants in various culture conditions. Especially in the culture of 2% cellulose, three transcript products were observed. First transcript was presumed to be a full length ORF that contained 11th intron with stop codon at position 2562 bp. The second one consisted of 12 exons and 11 introns with stop codon at position 1187 bp with 7th exon. The shortest transcript consisted of 10 exons and 9 introns with stop codon at 910 bp in the 7th exon. These premature stop codon might prevent the synthesis of fully active GHF74 or contribute for the production of protein with distinct function depending on the ambient carbon sources.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.2
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• pp.344-350
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• 1997

The present study was carried out to investigate the effects of zinc and vitamin E on the antioxidative defense mechanism in the liver of streptozotocin(STZ)-induced diabetic rats. Levels of blood glucose of STZ-diabetic rats were higher than that of control, but ZDM($ZnSO_{4}$ 10mg/kg injection+STZ) group was lower than those of DM(STZ injection) and EDM(vitamin E 400mg/kg diet+STZ) group. Levels of plasma insulin were lower in all three STZ-diabetic groups than those of control. Thiobarbituric acid reactive substances(TBARS) peroxide values(LPO) in liver were increased 2.3-fold in DM group compared with those of control, while LPG in ZDM group was lower than that of DM group, and EDM group had similar tendency compared with that of control. Reduced glutathione(GSH) contents of liver were decreased in DM group compared with those of control, but increased 2.3, 1.7-fold in ZDM and EDM groups, respectively, compared with those of DM group. Oxidized glutathione(GSSG) was increased in DM group compared with control and GSSG in ZDM and EDM group were lower than that of DM group. GSH/GSSG ratio had similar tendency compared with results of GSH. The activities of free radical scavenging enzymes such as superoxide dismutase, glutathione peroxidase and glutathione S-transferase were significantly decreased in DM group compared to those of control, but higher in ZDM and EDM groups than those of DM group. The metallothionein contents in liver and kidney were increased in DM and EDM groups were remarkably increased 20, 5.3-fold in ZDM group, compared with those of control.

• The Korean Journal of Zoology
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• v.33 no.4
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• pp.461-467
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• 1990

To investigate the neurological effect of acrylamide, whole brain of Intoxicated mouse induced early hindlimbs ataxia was examined by using the methods of SDS-PAGE and two-dimensional electrophoresis. In the gel patterns by SDS-PAGE, when the patterns of each group were compared relatively, there were no remakable changes but in the patterns of 2D-PAGE, some protein alterations were observed. Especially, the spots containing 20 (14,500, 5.64) and 21 (19,900, 6.78) were disappeared, and the spots 9 (31,300, 5.82), 11 (31,300, 5.36) and 19 (16,400, 5.42) showed marked decrease relatively in the case of treatment group. Among these changed spots, the spot 20 (14,500, 5.64) showed higher quantity than that of control group but several spots containing the spots 11 (31,300, 5.36), and 19(16.400, 5.42) were identical or equal to those of control In quantity in the case of recovery group. It seems that acrylamide might already inhibit the brain protein synthesis mechanism at the time of onset of distal neuropathy by participation in the protein metabolism so as to impair the brain regulation ability followed by a malfunction of mouse central nervous system (CNS) and recovery is gradually progressed with the dose and duration dependence after the cessation of acrylamide administration.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.8
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• pp.3541-3546
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• 2011

Autophagy is an evolutionarily conserved lysosomal pathway for degrading cytoplasmic proteins, macromolecules, and organelles in addition to recycling protein and ATP synthesis. Although autophagy is very important during embryogenesis, the mechanism underlying the dynamic development during this process remains largely unknown. In order to obtain insights into autophagy in early embryo development, we analyzed gene expression levels of autophagy-related genes (ATGs) in mouse embryos developing in vitro. Using real time RT-PCR technique, ATGs including Atg2a, Atg3, Atg4b, Atg5, Atg6, Atg7, Atg9a, and Wipi3, as maternal transcripts, were only up-regulated in 1-cell embryo stage before zygotic genomic activation (ZGA), and then expression decreased from 2-cell to blastocyst embryo stage. ATGs including Dram and Atg9b were expressed abundantly in 1-cell embryo state and in blastocyst embryo stage, athough Atg8 and Ulk1 were constantly expressed during preimplantation stage. However, Atg4d were only up-expressed from 4-cell to blastocyst stage. These results suggest that autophagy is related in mouse embryo, which possibly gives an important role for early development.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.117.2-117.2
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• 2011

Since Gratzel and co-workers developed a new type of solar cell based on the nanocrystalline TiO2 electrode, dye-sensitized solar cells (DSSCs) have attracted considerable attention on account of their high solar energy-to-conversion efficiencies (11%), their easy manufacturing process with low cost production compared to conventional p-n junction solar cells. The mechanism of DSSC is based on the injection of electrons from the photoexcited dye into the conduction band of nanocrystalline TiO2. The oxidized dye is reduced by the hole injection process from either the hole counter or electrolyte. Thus, the electronic structures, such as HOMO, LUMO, and HOMO-LUMO gap, of dye molecule in DSSC are deeply related to the electron transfer by photoexcitation and redox potential. To date, high performance and good stability of DSSC based on Ru-dyes as a photosensitizer had been widely addressed in the literatures. DSSC with Ru-bipyridyl complexes (N3 and N719), and the black ruthenium dye have achieved power conversion efficiencies up to 11.2% and 10.4%, respectively. However, the Ru-dyes are facing the problem of manufacturing costs and environmental issues. In order to obtain even cheaper photosensitizers for DSSC, metal-free organic photosensitizers are strongly desired. Metal-free organic dyes offer superior molar extinction coefficients, low cost, and a diversity of molecular structures, compared to conventional Ru-dyes. Recently, novel photosensitizers such as coumarin, merocyanine, cyanine, indoline, hemicyanine, triphenylamine, dialkylaniline, bis(dimethylfluorenyl)-aminophenyl, phenothiazine, tetrahydroquinoline, and carbazole based dyes have achieved solar-to-electrical power conversion efficiencies up to 5-9%. On the other hand, organic dye molecules have large ${\pi}$-conjugated planner structures which would bring out strong molecular stacking in their solid-state and poor solubility in their media. It was well known that the molecular stacking of organic dyes could reduce the electron transfer pathway in opto-electronic devices, significantly. In this paper, we have studied on synthesis and characterization of dendritic organic dyes with different number of electron acceptor/anchoring moieties in the end of dendrimer. The photovoltaic performances and the incident photon-to-current (IPCE) of these dyes were measured to evaluate the effects of the dendritic strucuture on the open-circuit voltage and the short-circuit current.

• Korean Journal of Environmental Agriculture
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• v.11 no.1
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• pp.67-76
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• 1992

A mechanistic study by which Cadmium-tolerant P.Putida C1 accumulates high conc of Cd in its cell body was performed. Approximately 57% Cd accumulated was distributed on the cell wall and the other 43% portion was in cytoplasm. 84% Cd of the Cd in the cell wall fractions present in the polyphosphate-polysaccharide fractions, but most of Cd in the cytoplasm fraction was in protein and nucleic acid. Cadmium affected the protein synthesis in P. Putida. The intracellular protein content was decreased by cadmium addition, but the soluble protein precipitated by ammonium sulfate($30{\sim}75%$ satruation) was increased as compared to that from the cells grwon without cadmium. Furthermore, in the cells grown with of cadmium, high-molecular-weight soluble protein was increased, with of cadmium, high-molecular-weight soluble protein was increased, compared with the cells grown without cadmium, but low-molecular-weight soluble protein was decreased. These results indicate that Cd inhibited the intracellular protein biosynthesis but enhance biosynthesis of the high-molecular-weight soluble protein precipitate by ammonium sulfate($30{\sim}75%$ saturation).