• Title/Summary/Keyword: Synthesis

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New Tactics for Stereospecificity in Metallocene-based Olefin Polymerization

  • Kim, Seong-Kyun;Park, Sung-Jin;Kim, Hwa-Kyu;Yoon, Seung-Woong;Lee, Jun-Seong;Park, Myung-Hwan;Do, Young-Kyu
    • Proceedings of the Polymer Society of Korea Conference
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    • 2006.10a
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    • pp.221-221
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    • 2006
  • The stereochemical control in polypropylenes and styrene-ethylene copolymers based on homogeneous single-site polymerization catalysts has received great attention since the stereocpecificity is one of the key factors in tailoring the polymer properties. Thus, we have developed new tactics for isospecificity in propylene polymerization with the unbridged metallocenebased systems and syndiospecific styrene-styrene sequence in styrene-ethylene copolymerization with the group 4 metallocene system. Brief details of the synthesis, structures and the polymerization behavior of a set of new metallocene catalysts will be presented.

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A Study of Mode of Action of Alachlor - I. Effects of Alachlor on Nucleic acid, Amino acid and Protein Synthesis in Oat(Avena sativa L.) (Alachlor의 제초기구(除草機構)에 관한 연구(硏究) - I.Alachlor가 귀리의 핵산(核酸), 아미노산 및 단백질합성(蛋白質合成)에 미치는 영향(影響))

  • Kwon, S.W.;Kim, J.C.
    • Korean Journal of Weed Science
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    • v.10 no.3
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    • pp.227-232
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    • 1990
  • The effects of alachlor [2-chloro-2', 6' diethyl-N-(methoxymethyl) acetanilide] treatment on nucleic acid, amino acid and protein synthesis were studied. The amide herbicide alachlor blocks the biosynthesis of the amino acids isoleucine, valine and aromatic amino acid in oat root tips. Nucleic acid was inhibited, but was not proportional to reduction in protein synthesis. $1{\times}10^{-4}M$ of alachlor treatment of oat roots inhibited 36% DNA synthesis, but DNA synthesis was not inhibited at $1{\times}10^{-5}M$. RNA synthesis was inhibited by $1{\times}10^{-5}M$ and $1{\times}10^{-4}M$ of alachlor 16 and 27%, respectively, while inhibition of protein synthesis did occur at same concentrations. Inhibition of protein synthesis also did not occur at concentration below $1{\times}10^{-4}M$ alachlor. It suggest that inhibition of protein sythesis caused significantly by alachlor($1{\times}l0^{-3}M$) result from secondary action.

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Characteristics of Prostaglandin Synthesis Induced by Bacterial Lipopolysaccharide in Rat Alveolar Macrophages (Bacterial Lipopolysaccharide가 Prostaglandin 합성에 미치는 작용의 특성)

  • 이수환;임종석;황동호;문창규
    • Journal of Food Hygiene and Safety
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    • v.8 no.4
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    • pp.181-188
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    • 1993
  • It is well known that bacterial lipopolysaccharide (LPS) stimulates the prostaglandin (PG) synthesis in various experimental system, but the mechanism and the detailed nature of its action are yet to be understood. Thus, this study was designed to characterize LPS induced PG synthesis in rat alveolar macrophage. Although results were not so much prominent, LPS stimulated PGE2 synthesis in macrophage with short term exposure, and this was thought to be mainly due to the activation of phopholipase A2+ But there was a burst in the PG synthesis 6 hours after the LPS treatment and this was accompanied with the increase of cyclooxygenase activity. This effect was not mediated by tumor necrosis factor (TNF) or platelet activating factor (PAF), and the existence of serum was prerequisite for its action. Growth factors such as epidermal growth factor (EGF) and platelet derived growth factor (PDGF) themselves did not stimulate PG synthesis and the showed stimulatory activities to some extent. Normal rat serum was more effective for the elicitation of the LPS action than growth factors. Thus, considering the amounts of growth fafctors contained in normal serum, it was suggested that another factors like LPS binding protein (LBP) might be involved in the serum effect on LPS action. Conclusively. it was thought that LPS could stimulate PG synthesis through interaction with serum factors such as EGF, PDGF and/or LBP.

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Solid-phase Synthesis of 7-Aryl-benzo[b][1,4]oxazin-3(4H)-one Derivatives on a BOMBA Resin Utilizing the Smiles Rearrangement

  • Lee, Ji-Min;Yu, Eun-Ae;Park, Joo-Yeon;Ryu, In-Ae;Shin, Dong-Soo;Gong, Young-Dae
    • Bulletin of the Korean Chemical Society
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    • v.30 no.6
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    • pp.1325-1330
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    • 2009
  • A general method has been developed for the solid phase synthesis of drug-like 7-aryl-benzo[b][1,4]oxazin-3(4H)- one derivatives 6. The method relies on a novel, microwave irradiation promoted cyclization reaction of the BOMBA resin bound, N-substituted-$\alpha$-(2-chloro-4-bromophenoxy)acetamide 3 that takes place via a Smiles rearrangement. The 7-bromobenzo[1,4]oxazine 4, produced in this process is converted to 7-aryloxazin analogs 5 by utilizing Suzuki coupling with various substituted arylboronic acids. Finally, the target 7-aryl-benzo[b][1,4]oxazin-3(4H)-ones 6 are liberated from the resin by treatment with 5% TFA. The progress of the reactions involved in this preparative route can be monitored by using ATR-FTIR spectroscopy on a single bead. The target compounds, obtained by using this five-step sequence, are produced in high yields and purities.

Effects of Taurine on Lipid Metabolism and Protein Synthesis in Poultry and Mice

  • Shim, K.S.;Jung, H.J.;Na, C.S.;Yoon, C.;Park, Garng H.
    • Asian-Australasian Journal of Animal Sciences
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    • v.22 no.6
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    • pp.865-870
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    • 2009
  • In this study, we have attempted to understand the effects of taurine on serum and liver concentrations of cholesterol and triglycerides in broiler chickens and mice in the post-absorptive state, and on in vitro protein synthesis in the livers of broiler chickens and laying hens, as well as the effects of taurine on in vivo protein synthesis in the liver of mice. The experimental animals were subjected to 24 h of starvation in order to perpetuate a post-absorptive state. Serum concentrations of high density lipoprotein cholesterol and triglycerides were significantly (p<0.05) higher in the taurine groups than in the controls in both the broilers and the mice. However, taurine resulted in a significant (p<0.05) reduction in liver concentrations of total cholesterol and triglycerides, relative to what was seen in the control groups of both animals. Taurine stimulated the in vitro synthesis of 57-kDa, 40-kDa and 23-kDa proteins in the liver of broilers, but inhibited the in vitro synthesis of 54-kDa, 37-kDa and 24-kDa proteins. Taurine in the liver of laying hens exerted effects on in vitro protein synthesis, with the exception of the 26-kDa protein which was not detected in broiler liver, but was inhibited by taurine in the liver of laying hens. Unlike the findings regarding in vitro protein synthesis in the liver of broilers or laying hens, taurine appeared to stimulate the synthesis of only two proteins, a 47-kDa and a 40-kDa protein, in the liver of mice. Overall, theses findings indicate that taurine treatment results in a reduction in cholesterol and triglyceride concentrations, and also affects protein synthesis in the livers of broilers, laying hens, and mice.

Synchrotron Grazing Incidence X-ray Scattering and Its Applications in Polymer Nanotechnology

  • Ree, Moon-Hor;Lee, Byeong-Du;Yoon, Jin-Hwan;Heo, Kyu-Young;Jin, Kyeong-Sik;Jin, Sang-Woo;Kim, Hyun-Chul;Kim, Gha-Hee;Choi, Seung-Chul;Oh, Weon-Tae;Park, Young-Hee;Hwang, Yong-Taek;Kim, Jong-Seong
    • Proceedings of the Polymer Society of Korea Conference
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    • 2006.10a
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    • pp.120-120
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    • 2006
  • In our study grazing incidence X-ray scattering (GIXS) measurements with synchrotron radiation sources were conducted statically and in-situ for a series of nanoscale thin films prepared from nanoporous dielectrics, block copolymers, brush polymers, and molecular assemblies. All GIXS measurements were performed at the Pohang Accelerator Laboratory. The measured scattering data were analyzed in detail by using newly developed GIXS scattering theory. All GIXS results will be discussed in details with considering the materials chemistry and nanostructure formation process parameters.

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Modeling, Preparation, and Elemental Doping of Li7La3Zr2O12 Garnet-Type Solid Electrolytes: A Review

  • Cao, Shiyu;Song, Shangbin;Xiang, Xing;Hu, Qing;Zhang, Chi;Xia, Ziwen;Xu, Yinghui;Zha, Wenping;Li, Junyang;Gonzale, Paulina Mercedes;Han, Young-Hwan;Chen, Fei
    • Journal of the Korean Ceramic Society
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    • v.56 no.2
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    • pp.111-129
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    • 2019
  • Recently, all-solid-state batteries (ASSBs) have attracted increasing interest owing to their higher energy density and safety. As the core material of ASSBs, the characteristics of the solid electrolyte largely determine the performance of the battery. Thus far, a variety of inorganic solid electrolytes have been studied, including the NASICON-type, LISICON-type, perovskite-type, garnet-type, glassy solid electrolyte, and so on. The garnet Li7La3Zr2O12 (LLZO) solid electrolyte is one of the most promising candidates because of its excellent comprehensively electrochemical performance. Both, experiments and theoretical calculations, show that cubic LLZO has high room-temperature ionic conductivity and good chemical stability while contacting with the lithium anode and most of the cathode materials. In this paper, the crystal structure, Li-ion transport mechanism, preparation method, and element doping of LLZO are introduced in detail based on the research progress in recent years. Then, the development prospects and challenges of LLZO as applied to ASSBs are discussed.

UV Actions in Plant Photomorphogenesis -Induction and Amplification of Anthocyanin Synthesis in Broom Sorghum-

  • Shichijo, Chizuko;Yatsuhashi, Hiroko;Hashimoto, Tohru
    • Journal of Photoscience
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    • v.9 no.2
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    • pp.338-340
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    • 2002
  • In broom sorghum, Sorghum bicolor Moench, UV causes anthocyanin synthesis having action peaks in UVA and UVB regions. We previously reported that UV induces anthocyanin synthesis through UVB photoreceptor and phytochrome activated by UV. Furthermore, UVA and UVB amplify phytochrome-induced anthocyanin synthesis (PIAS). Our action- spectroscopic research indicated that a UV -receptor for amplification of PIAS is likely to be the same or same type of UVB photoreceptor for induction of anthocyanin synthesis. UVA-amplification of PIAS can be explained by the action of a cryptic red light signal (CRS), an amplification factor for PIAS produced by a distinct phytochrome-species activated by UVA. We suggest that UVA photoreceptors are not involved in anthocyanin synthesis in the broom sorghum.

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Combustion Characteristics of Synthesis Gas Generated in Waste Pyrolysis Process (폐기물 열분해과정에서 발생된 합성가스의 연소 특성)

  • Ahn, Yong-Soo;Hwang, Sang-Soon;Lee, Sung-Ho;Lee, Hyup-Hee
    • 한국연소학회:학술대회논문집
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    • 2003.05a
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    • pp.143-150
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    • 2003
  • The synthesis gas generated in waste pyrolysis melting process which consists of pyrolysis of waste and melting process of ash is known to be an alternative fuel. Since the compositopn of synthesis gas is much different from other synthesis gases, the fundamental combustion characteristics are analyzed in this study. The radiation heat heat flux is used to estimate the heat flux from flames made by many combinations of fuel and oxidant supply. The results show that the synthesis gas needs much more amount of oxidant for equivalent heat flux to methane flame and the inverse diffusion flame type for synthesis gas burner is suitable for better radiation heat transfer.

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The Synthesis of Ester Compound by Lipase in Organic Solvents (유기용매계에서 리파제에 의한 에스테르 화합물 합성)

  • Kim, Boo-Chul;Lee, Jae-Dong;Lee, Tae-Ho
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.23 no.3
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    • pp.496-501
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    • 1994
  • The synthesis of lauryl palmitate from palmitic acid and lauryl alcohol was investigated in organic solvents using lipase. Water-immiscible organic solvent such as hexane, toluenem cyclohexane, and isooctane were found to be suitable of ester synthesis . The effect of water content on the initial rate of conversion was examined . As the content increased, the reaction rate increased. But addition of water in organic solvent decreased therostability of enzyme . The best lauryl palmitate synthesis was achieved with water content of 0.2-0.4% reaction temperature of 4$0^{\circ}C$ and 45$^{\circ}C$ for Candida cylindracea lipase porcine, pancreatic lipase, respectively. when ester synthesis was carried out under the optimum conditions, the conversion yield of palmitate into lauryl palmitate after 70hrs reached 85% and 69 % for the Candida cylindracea lipase and porcine opancreatic lipase, respectivley.

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