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공경택,김홍곤 한국공업화학회 2003 응용화학 Vol.7 No.2
Preparation of 1,1,2,3,3,3-hexafluoropropyl methyl ether(HFE-356mec), a prospective foam blowing agent replacing CFC-11, has been studied under a basic condition. Etherification of hexafluoropropylene(HFP) withe CH₃OH occurrdd in a liquid phase having basic catalysts. Reaction temperatures lower than 30℃ produced high yields and high selectivities of the ether product. The effect of temperature indicated that the amount of HFP dissolved in methanol may play the major role to control the production rate of the HFE-356mec.
Role of Alloying Elements on the Cytotoxic Behavior and Corrosion of Austenitic Stainless Steels
Kim, Young Sik,Yoo, Y.R.,Sohn, C.G.,Oh, Keun Taek,Kim, Kyoung Nam,Yoon, Jae Hong,Kim, H.S. Trans Tech Publications, Ltd. 2005 Materials science forum Vol.475 No.-
<P>Super stainless steel has been used to solve corrosion problems of biomaterials because it shows the excellent corrosion resistance as like Ti and Ti alloys and has better mechanical properties than Ti and Ti alloys. We designed high Mo and Ni bearing super austenitic stainless steel. To obtain desirable microstructure, Cr, Ni, Mo, N contents were controlled. This work focused on the role of alloying elements on cytotoxic behavior and corrosion of stainless steel. In acidic chloride solution, when the alloys had high PRE values, the alloys showed high pitting resistance and low critical current density. However, in Hanks’ solution, the higher PRE’s alloys showed high critical passive current density. Namely, it was revealed that EDTA among Hanks’ solution played an important role to increase the critical passive current density of high Mo and Ni bearing super stainless steels, regardless of PRE’s value of the alloys. Therefore, even if the PRE values of the alloys were higher, high Ni and Mo bearing alloys would reveal more cytotoxic and high metal ion release rate than 316L stainless steel.</P>
Effect of Powder Size of Mg-Zn-Y Alloy on the Consolidation
Kim Taek-Soo,Chae H.J.,Lee J.K.,Jung H.G.,Kim Y.D.,Bae J.C. 한국분말야금학회 2006 한국분말야금학회 학술대회논문집 Vol.2006 No.1
alloy powders were prepared using an industrial scale gas atomizer, followed by warm extrusion. The powders were almost spherical in shape. The microstructure of powders as atomized and bars as extruded was examined as a function of initial powder size distribution using Scanning Electron Microscope (SEM), Energy Dispersive X-ray Spectroscope (EDS) and X-ray Diffractometer (XRD). The grain sizes were decreased with extruding as well as decreasing the initial powder sizes. Both the ultimate strength and elongation were enhanced as the initial powder sizes were decreased.
Yun, Eun Ju,Lee, Saeyoung,Kim, Ji Hye,Kim, Bo Bae,Kim, Hee Taek,Lee, Sun Hee,Pelton, Jeffrey G.,Kang, Nam Joo,Choi, In-Geol,Kim, Kyoung Heon Springer-Verlag 2013 Applied microbiology and biotechnology Vol.97 No.7
<P>3,6-Anhydro-L-galactose (L-AHG) constitutes 50% of agarose, which is the main component of red macroalgae. No information is currently available on the mass production, metabolic fate, or physiological effects of L-AHG. Here, agarose was converted to L-AHG in the following three steps: pre-hydrolysis of agarose into agaro-oligosaccharides by using acetic acid, hydrolysis of the agaro-oligosaccharides into neoagarobiose by an exo-agarase, and hydrolysis of neoagarobiose into L-AHG and galactose by a neoagarobiose hydrolase. After these three steps, L-AHG was purified by adsorption and gel permeation chromatographies. The final product obtained was 95.6% pure L-AHG at a final yield of 4.0% based on the initial agarose. In a cell proliferation assay, L-AHG at a concentration of 100 or 200 μg/?mL did not exhibit any significant cytotoxicity. In a skin whitening assay, 100 μg/?mL of L-AHG showed significantly lower melanin production compared to arbutin. L-AHG at 100 and 200 μg/?mL showed strong anti-inflammatory activity, indicating the significant suppression of nitrite production. This is the first report on the production of high-purity L-AHG and its physiological activities.</P>
Highly Efficient Organic THz Generator Pumped at Near‐Infrared: Quinolinium Single Crystals
Kim, Pil‐,Joo,Jeong, Jae‐,Hyeok,Jazbinsek, Mojca,Choi, Soo‐,Bong,Baek, In‐,Hyung,Kim, Jong‐,Taek,Rotermund, Fabian,Yun, Hoseop,Lee, Yoon Sup,Gü,nter, Peter,Kwon, O WILEY‐VCH Verlag 2012 Advanced functional materials Vol.22 No.1
<P><B>Abstract</B></P><P>A novel highly efficient ionic electro‐optic quinolinium single crystals for THz wave applications is reported. Acentric quinolinium derivatives, HMQ‐T (2‐(4‐hydroxy‐3‐methoxystyryl)‐1‐methylquinolinium 4‐methylbenzenesulfonate) and HMQ‐MBS (2‐(4‐hydroxy‐3‐methoxystyryl)‐1‐methylquinolinium 4‐methoxybenzenesulfonate) exhibit high order parameters cos<SUP>3</SUP><I>θ</I><SUB>p</SUB> = 0.92 and cos<SUP>3</SUP><I>θ</I><SUB>p</SUB> = 1.0, respectively, as well as a large macroscopic optical nonlinearity, which is in the range of the benchmark stilbazolium DAST (<I>N,N</I>‐dimethylamino‐<I>N</I>’‐methylstilbazolium 4‐methylbenzenesulfonate) and phenolic polyene OH1 (2‐(3‐(4‐hydroxystyryl)‐5,5‐dimethylcyclohex‐2‐enylidene)malononitrile) crystals. As‐grown unpolished bulk HMQ‐T crystals with a side length of about 6 mm and thickness of 0.56 mm exhibit 3.1 times higher THz generation efficiency than 0.37 mm thick OH1 crystals and about 8.4 times higher than 1 mm thick inorganic standard ZnTe crystals at the near‐infrared fundamental wavelength of 836 nm. Therefore, HMQ crystals with high order parameter obviously have a very high potential for high power THz‐wave generation and its applications.</P>
Kim, Kibong,Choi, Shin Hei,Jeon, June,Lee, Hyosun,Huh, Jung Oh,Yoo, Jaeduk,Kim, Jong Taek,Lee, Chang-Hee,Lee, Yoon Sup,Churchill, David G. American Chemical Society 2011 Inorganic Chemistry Vol.50 No.12
<P>One 8-phenyl and two 8-mesityl-substituted “scorpionate”-like BODIPY-type species of the formula [3,4,4-tris(5-<I>R</I>-(2-thienyl))-8-(2,4,6-<I>R′</I>-phenyl)-4-bora-3a,4a-diaza-<I>s</I>-indacene (R = H, R′ = H, <B>3a</B>; R, = H, R′ = Me, <B>2a</B>; R, = Me, R′ = Me, <B>2b</B>)] have been synthesized and fully characterized. Importantly, differences in their solution (MeCN) optical Cu<SUP>2+</SUP> and Hg<SUP>2+</SUP> probing capacity via <I>SSS</I>-chelation were investigated. Compounds <B>2a</B>–<B>3a</B> were prepared from the requisite 8-substituted BODIPY complexes. They were characterized first by complete <SUP>1</SUP>H, <SUP>11</SUP>B and <SUP>13</SUP>C NMR spectroscopic assignments (CD<SUB>3</SUB>Cl or CD<SUB>3</SUB>C(O)CD<SUB>3</SUB>); the molecular structures of <B>2a</B> and <B>3a</B> were determined by X-ray crystallography. Compounds <B>2a</B>–<B>3a</B> were studied by UV–vis and fluorescence spectroscopy [Φ<SUB>F</SUB> = 0.27 ± 0.013 (<B>2a</B>); 0.024 ± 0.0016 (<B>2b</B>); 0.0034 ± 0.00047 (<B>3a</B>)]. Importantly, low [Cu<SUP>2+</SUP>] with <B>3a</B> (<3.0 × 10<SUP>–5</SUP> M) gave rise to an increase of fluorescence intensity (off–on; 6.3-fold), whereas with <B>2a</B> it decreased (on–off). When [Hg<SUP>2+</SUP>] (<3.0 × 10<SUP>–5</SUP> M) was added to <B>2b</B>, the λ<SUB>em,max</SUB> value increased (off–on<I>;</I> 3.2-fold), and for <B>2a</B>, it decreased (on–off). The association constant (<I>K</I><SUB>a</SUB>) for Hg<SUP>2+</SUP>·<B>2a</B> was determined to be 3120 ± 307 M<SUP>–1</SUP>. An approximate stoichiometric 1:1 binding determined by Job plot analysis is in line with successful DFT modeling of <I>SSS</I>-Cu<SUP>2+</SUP> binding for this system type. <SUP>1</SUP>H NMR spectroscopy also revealed tentative sets of product complex peaks. These simple differences caused by formal ligand Me-group incorporation are the first for any related fluorophores, to the best of our knowledge.</P><P>Three new “scorpionate”-like BODIPY species have been isolated and characterized. They exposed interesting differences in low [Cu<SUP>2+</SUP>] and [Hg<SUP>2+</SUP>] on−off and off−on fluorescence responses through formal methyl group placement into the fluorophore skeleton.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/inocaj/2010/inocaj.2010.50.issue-12/ic101681h/production/images/medium/ic-2010-01681h_0004.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ic101681h'>ACS Electronic Supporting Info</A></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ic101681h'>ACS Electronic Supporting Info</A></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ic101681h'>ACS Electronic Supporting Info</A></P>
Recovered changes in the spleen by agmatine treatment after transient cerebral ischemia
D Uranchimeg,Jae Hwan Kim,Jae Young Kim,Won Taek Lee,Kyung Ah Park,G Batbaatar,S Tundevrentsen,D Amgalanbaatar,Jong Eun Lee 대한해부학회 2010 Anatomy & Cell Biology Vol.43 No.1
Stroke or cerebrovascular injury is the leading cause of disability and the third leading cause of deaths worldwide. After the initial ischemic injury, sympathetic signals are transmitted to the spleen and a compromised blood-brain barrier, coupled with expression of adhesion molecules by the vascular endothelial cells permits an influx of peripheral immune cells. This influx of peripheral immune cells into the brain exacerbates the local brain inflammatory response, leading to enhanced neurodegeneration. Agmatine is a primary amine formed by decarboxylation of L-arginine synthesized in the mammalian brain. In this study, we determined the effect of agmatine on the immune response in the spleen after transient cerebral ischemia. Twenty-three hours after transient cerebral ischemia, the white pulp area was reduced and the number of CD11b+ macrophages and CD4+CD25+ regulatory T cells (T reg cells) were increased in the spleens in the experimental group as a result of alteration of the immune response in the spleen, as regulated by inflammatory cytokines. In the agmatine treatment group (100 mg/kg IP), the contraction of white pulp was diminished and the number of CD11b+ macrophages and CD4+CD25+T reg cells were decreased. Twenty-three hours after transient cerebral ischemia, the brain infarction area was significantly reduced (5.51±1.63% of the whole brain) in the agmatine treatment group compared to 15.02±4.28% of the whole brain in the experimental control group. These results suggest that agmatine treatment can reduce brain infarction through minimizing neuroinflammation and can lessen the danger of post-stroke infection from depression of the immune system after stroke
Yoon, In-Sun,Kim, Jeong-Hoe,Yi, Ho-Chul,Park, Don-Ha,Kim, Woo-Taek,Kang, Bin-G. Plant Molecular Biology & Biotechnology Research C 1994 Plant molecular biology and biotechnology research Vol.1994 No.
We have investigated hormonal control of gene expression for the two most important ethylene biosynthetic enzymes in mungbean hypocotyls. Three different cDNA clones (pVR-ACS1, pVR-ACS6 and pVR-ACS7) for ACC synthase and one (pVR-ACO1) for ACC oxidase were used as probes for Northern blot analyses. All three ACC synthase genes were induced by auxin treatment. However, the transcript level of VR-ACS1 was also increased by kinetin and ABA, respectively, the latter being a strong inhibition to auxin. Expression of VR-ACS1 gene was very sensitive to negative regulation of ethyelne. Our results suggest that VR-ACS1 and Exogenously applied ethyelne induces a large increase in the transcript level of VR-ACO1 gene. This ethylene-induction of VR-ACO1 was supressed by ABA treatment indicating that ABA antagonized the ethylene action. In an effort to have insight into hormone signalling pathway, we investigated the effect of agents influencing protein phosphorylation on the genes for ACC synthas and ACC oxidase. Staurosporin (STA), a protein kinase inhibitor, completely abolished both the ethylene-induction of VR-ACO1 gene and ethylene-supression of VR-ACS1 gene. This strongly sugessts that some positively regulating protein kinases are involved in the ethylene signalling pathway. On the other hand, treatment of NaF,an inhibitor of protein phosphatase, completely inhibit both auxin-induced ethylene production and expression of genes for VR-ACS6 and VR-ACS7, implicating an important role of protein dephosphorylation for auxin action. Our findings indicate that protein phosphylation and dephosporylation may be involved in the transduction of hormonal signals leading to the induction of both ACC synthase and ACC oxidase gene. Further characterzation is in progress.