• 제목/요약/키워드: synthesis of $MgB_2$

검색결과 138건 처리시간 0.023초

Synthesis and anticonvulsant evaluation of a series of (R)-and (S)-N-Cbz-.alpha.-aminosuccinmide and their structure activity relationship

  • Lee, Jae-Won;Choi, Jong-Won;Park, Min-Soo
    • Archives of Pharmacal Research
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    • 제19권4호
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    • pp.312-316
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    • 1996
  • A series of N-Cbz${alpha}$-aminosucinimides (1), combining common moieties of various anticonvulsants such as N-CO-C-N and cyclic imide in a single molecule, were synthesized from the corresponding (R)- and (S)-N-Cbz-aspartic acid (2). And their in vivo anticonvulsant evaluations in MES and PTZ test were investigated. And also the rotorod test for neurotoxicity was investigated. All the tested compounds (1), except 1c and 1f, showed significant anticonvulsant activities in both MES and PTZ test. And the most active compound among them in MES test was (R)-N-Cbz-${alpha}$-amino-N-methylsuccinimide (1b) $(ED_50/=52.5 mg/kg)$ and (S)-N-Cbz-aminosuccinimide((1d) was most active in PTZ test $(ED_50/=78.1 mg/kg)$. And the $TD_50$ values of the tested compounds were above 117.5 mg/kg. These pharmacological data were comparable to those of currently available anticonvulsants. And also we found that the pharmacological effects were dependent on their N-substituted alkyl chains and their stereochemistry.

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Synthesis and Characterization of (THF)3 Li(NC)CU(C6H3-2,6-Mes2)and Br(THF)2 Mg(C6H3-2,6-Trip2) (Mes = C6H2-2,4,6-Me3; Trip = C6H2-2,4,6-i-Pr3): The Structures of a Monomeric Lower-Order Lithi

  • Hwang, Cheong-Soo;Power, Philip P.
    • Bulletin of the Korean Chemical Society
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    • 제24권5호
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    • pp.605-609
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    • 2003
  • The lower-order lithium organocyanocuprate compound, (THF)₃Li(NC)Cu($C_6$H₃-2,6-Mes₂) (1), and the bulky terphenyl Grignard reagent, Br(THF)₂Mg($C_6$H₃-2,6-Trip₂) (2), have been synthesized and structurally characterized both in the solid state by single crystal x-ray crystallography and in solution by multi-nuclear NMR and IR spectroscopy. The compound (1) was isolated as a monomeric contact ion-pair in which the C (organic ipso)-Cu-CN-Li atoms are coordinated linearly. The lithium has a tetrahedral geometry as a result of solvation by three THF molecules. The compound (1) is the first example of fully characterized monomeric lower order lithium organocyanocuprate. The bulky Grignard reagent (2) was also isolated as a monomer in which the magnesium, solvated by two THF molecules, has a distorted tetrahedral geometry. The crystals of (1) possess triclinic symmetry with the space group $P{\={1}}$, Z = 2, with a = 12.456(3) Å, b = 12.508(3) Å, c = 13.904(3) Å, α = 99.81°, β = 103.72(3)°, and γ = 119.44(3)°. The crystals (2) have a monoclinic symmetry of space group $P2_{1/C}$, Z = 4, with a = 13.071(3) Å, b = 14.967(3) Å, c = 22.070(4) Å, and β = 98.95(3)°.

Protective Effects of Standardized Siegesbeckia glabrescens Extract and Its Active Compound Kirenol against UVB-Induced Photoaging through Inhibition of MAPK/NF-κB Pathways

  • Kim, Jongwook;Kim, Mi-Bo;Yun, Jun Gon;Hwang, Jae-Kwan
    • Journal of Microbiology and Biotechnology
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    • 제27권2호
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    • pp.242-250
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    • 2017
  • Anti-photoaging effects of standardized Siegesbeckia glabrescens extract (SGE) and its major active compound kirenol were investigated using Hs68 human dermal fibroblasts and hairless mice, respectively. UVB-irradiated hairless mice that received oral SGE (600 mg/kg/day) showed reduced wrinkle formation and skinfold thickness compared with the UVB-irradiated control. Furthermore, SGE treatment increased the mRNA levels of collagen synthesis genes (COL1A1, COL3A1, COL4A1, and COL7A1) and activated antioxidant enzyme (catalase), while suppressing matrix metalloproteinase (MMP-2, -3, -9, and -13) expression. In Hs68 fibroblasts, kirenol also significantly suppressed MMP expression while increasing the expression of COL1A1, COL3A1, and COL7A1. Collectively, our data demonstrate that both SGE and kirenol attenuated UVB-induced photoaging in hairless mice and fibroblasts through inhibition of the mitogen-activated protein kinases and nuclear factor kappa B pathways, suggesting that SGE has potential to serve as a natural anti-photoaging nutraceutical.

Formation of Succinic Acid by Klebsiella pneumoniae MCM B-325 Under Aerobic and Anaerobic Conditions

  • Thakker Chandresh;Bhosale Suresh;Ranade Dilip
    • Journal of Microbiology and Biotechnology
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    • 제16권6호
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    • pp.870-879
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    • 2006
  • The present study describes the formation of succinic acid by a nonvirulent, highly osmotolerant Klebsiella pneumoniae strain SAP (succinic acid producer), its profile of metabolites, and enzymes of the succinate production pathway. The strain produced succinate along with other metabolites such as lactate, acetate, and ethanol under aerobic as well as anaerobic growth conditions. The yield of succinate was higher in the presence of $MgCO_3$ under $N_2$ atmosphere as compared with that under $CO_2$ atmosphere. Analysis of intracellular metabolites showed the presence of a smaller PEP pool than that of pyruvate. Oxaloacetate, citrate, and $\alpha$-ketoglutarate pools were considerably larger than those of isocitrate and fumarate. In order to understand the synthesis of succinate, the enzymes involved in end-product formation were studied. Levels of phosphoenolpyruvate carboxykinase, fumarate reductase, pyruvate kinase, and acetate kinase were higher under anaerobic growth conditions. Based on the profiles of the metabolites and enzymes, it was concluded that the synthesis of succinate took place via oxaloacetate, malate, and fumarate in the strain under anaerobic growth conditions. The strain SAP showed potential for the bioconversion of fumarate to succinate under $N_2$ atmosphere in the presence of $MgCO_3$. At an initial fumarate concentration of 10 g/l, 7.1 g/l fumarate was converted to 7 g/l succinate with a molar conversion efficiency of 97.3%. The conversion efficiency and succinate yield were increased in the presence of glucose. Cells grown on fumarate contained an 18-fold higher fumarate reductase activity as compared with the activity obtained when grown on glucose.

Yonsei Evolutionary Population Synthesis for Old Stellar Systems

  • 정철
    • 천문학회보
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    • 제37권1호
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    • pp.31.2-31.2
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    • 2012
  • We present the Yonsei Evolutionary Population Synthesis (YEPS) models for spectroscopic and photometric evolutions of simple and composite stellar populations. The models are based on the most up-to-date Yonsei-Yale stellar evolutionary tracks and BaSel 3.1 flux libraries, and provide integrated spectroscopic quantities of Lick/IDS system including high-order Balmer absorption-lines. Special care has been taken to incorporate the systematic variation of horizontal branch (HB) morphology as functions of metallicity, age, alpha-element mixture, and helium abundance of simple stellar populations. Our models for normal-helium stellar populations indicate that the realistic modeling of HB and alpha-element brings about 5 Gyr and 0.1 dex differences in age and metallicity estimations, respectively, compared to those without these effects. The HB effect does not depend on the specific choice of stellar libraries and alpha-element enhancements, and this effect is non-negligible even in the metal sensitive absorption indices, such as Mg2 and Mg b. Comparison of the models to observations reveals that the HB and alpha-element effects are critical in understanding otherwise inexplicable phenomena found in globular cluster systems in the Milky Way and nearby galaxies, including the observed bimodality of the line strengths of globular clusters in massive galaxies. In addition, we found that helium-enhanced stellar populations, which are the major sources of extreme HB stars, bring about increased FUV, NUV fluxes, and thus the model colors of those filters become extremely blue. Age dating based on the YEPS model with normal-helium stellar populations reveals that the evidence for 'downsizing' of elliptical galaxies is found not only in the local field but also in Coma cluster, and that the mean age of elliptical galaxies in Coma cluster is about 1.4 Gyr younger than the mean age of those in the local field. We also find that our models with helium-enhanced subpopulations can naturally reproduce the strong UV-upturns observed in giant elliptical galaxies assuming an age similar to that of old GCs in the Milky Way.

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유기노의 항산화 활성 및 멜라닌 생성 억제 효과 (Effect of Artemisia anomala S. Moore on Antioxidant Activity and Melanogenesis)

  • 이범천;김진화;김진희;표형배;;박흠대;조영호
    • 생약학회지
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    • 제36권4호통권143호
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    • pp.273-277
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    • 2005
  • In mammalian melanocytes, melanin synthesis is controlled by tyrosinase, the key enzyme in the pigment synthesis. In this study, to develop a new whitening agent, we have investigated the antioxidant and the inhibitory effect of Artemisia anomala extract on tyrosinase activity and melanigenesis in the B16/F1 melanoma cells. The inhibition ratio of tyrosinase activity of butanol fraction from A. anomala was higher than that of arbutin ($97.5{\pm}0.5%$ at the concentration of 2 mg/ml). The butanol fraction was shown scavenging activities of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and superoxide anion radicals in a dose dependent manner. The highest inhibitory activity of melanogenesis was also butanol fraction ($25.0{\pm}3%$ at the concentration of $200\;{\mu}g/ml$). From these results, we suggest that the A. anomala extract might be used to be a potential agent for skin whitening.

A Study of Mechanism Involved in Cadmium-induced Platelet Aggregation

  • 송철수;홍기환
    • 대한약리학회지
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    • 제20권1호
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    • pp.41-46
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    • 1984
  • 카드뮴중독으로 혈소판응집이 항진되어 고혈압 또는 동맥경화증이 발생한다는 연구보고를 감안하여 가토와 흰쥐의 생체내 실험으로서 미세혈전의 형성, Malondialdehyde(MDA) 및 thromboxane $B_2(TXB_2)$치에 미치는 카드뮴의 효과를 검토하고, in vitro실험으로 카드뮴을 처치한 가토 대동맥절편이 혈소판응집에 미치는 영향을 관찰하였으며, prostacyclin의 합성능력을 측정하여 그 결과를 다음과 같이 요약하였다. 1)Cadmium chloride 2mg/kg을 매주 동물의 복강내에 주입하였을 때 미세혈전형성이 증가되었다. 2) 카드뮴 중독동물의 platelet-rich plasma (PRP)는 MDA와 $TXB_2$형성이 정상동물에서 보다 현저히 증가되었다. 3) 카드뮴을 중독시킨 가토의 platelet-poor plasma (PPP)에서의 lipid peroxide치는 대조군과 차이가 없었다. 4) In vitro 실험으로, 가토대동맥 절편에서의 6-keto-$PGF_{1{\alpha}}$의 생성은 카드뮴 농도에 비례하여 억제되었고 이때 혈소판 응집률의 증가와 평행하였다. 5) 이상의 결과로서 카드뮴은 동맥내피세포에서 prostacyclin 합성을 억제할 뿐만 아니라 혈소판에서 $TXA_2$합성을 촉진시켜 그 결과로 혈소판 응집률을 증가시켰음을 알 수 있었다.

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Hydrothermal Synthesis of Cubic Mesocrystal CeO2 for Visible Photocatalytic Degradation of Rhodamine B

  • Yang, Hexiang;Zhou, Mengkai;Meng, Zeda;Zhu, Lei;Chen, Zhigang;Oh, Won-Chun
    • 한국재료학회지
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    • 제25권3호
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    • pp.144-148
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    • 2015
  • Cubic mesocrystal $CeO_2$ was synthesized via a hydrothermal method with glutamic acid ($C_5H_9NO_4$) as a template. The XRD pattern of a calcined sample shows the face-centered cubic fluorite structure of ceria. Transmission electron microscopy (TEM) and the selected-area electron diffraction (SAED) pattern revealed that the submicron cubic mesocrystals were composed of many small crystals attached to each other with the same orientation. The UV-visible adsorption spectrum exhibited the red-shift phenomenon of mesocrystal $CeO_2$ compared to commercial $CeO_2$ particles; thus, the prepared materials show tremendous potential to degrade organic dyes under visible light illumination. With a concentration of a rhodamine B solution of 20 mg/L and a catalyst amount of 0.1 g/L, the reaction showed higher photocatalytic performance following irradiation with a xenon lamp (${\geq}380nm$). The decoloring rate can exceed 100% after 300 min.

새로운 플라보노이드 유도체인 DA-6034의 TNBS 유발성 염증성대장염 모델에서의 치료효과 (Effect of DA-6034, a New Flavonoid Derivative, on TNBS-Induced Colitis in the Rats)

  • 손미원;고준일;김희기;장동경;유무희;김원배;이강춘;송인성
    • 약학회지
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    • 제42권2호
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    • pp.205-213
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    • 1998
  • The efficacy of DA-6034, a new flavonoid derivative, was investigated in comparison with sulfasalazine in a trinitrobenzene sulfonic acid (TNBS)-induced rat colitis. Under light anaesthesia with ether, rats were subjected to intracolonic administration of 30mg TNBS in 50% ethanol (0.5ml) and were then sacrificed at 7 or 21 days after colitis induction. The TNBS control group (the saline treated colitic rat) exhibited ulceration and inflammation of the distal colon with formation of granuloma and pathologic connections. Moreover, an increase in colonic myeloperoxidase (MPO) activity (investigated as an index of leukocyte adhesion and accumulation) and an elevated colonic leukotriene $B_4$ ($LTB_4$) level were observed. The colitic rats received DA6034 (0.3-30mg/kg) or sulfasalazine (50-100mg/kg), prednisolone (0.3-3mg/kg) after the induction of colitis until they were sacrificed. Oral treatment with DA-6034 resulted in significant reductions of macroscopic colonic damage, colonic inflammation. DA6034 had a more potent effect than sulfasalazine and prednisolone on macroscopic colonic damage, while it has similar effect with prednisolone on the reduction of colonic $LTB_4$ synthesis and MPO activity. This study show, therefore, that DA-6034 is effective m attenuating the colonic lesion in an TNBS-induced colitis model. Furthermore, the results suggest that the effect of DA-6034 is partially related to its action on $LTB_4$ synthesis and MPO inhibition.

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V2O5가 고용된 Karrooite계의 Brown색 안료합성과 특성 (Synthesis and Characterization of V2O - Doped Karrooite Brown Pigments)

  • 김금선;이병하
    • 한국세라믹학회지
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    • 제48권4호
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    • pp.303-306
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    • 2011
  • [ $V_2O_5$ ]doped Karrooite pigments were synthesized by the solid state method to get stabilized brown pigment in oxidation and reduction atmosphere. Optimum substitution condition and limited dopant with $V_2O_5$ for Karrooite pigment was investigated. With calcination at $1250^{\circ}C{\sim}1400^{\circ}C$, compositions were designed varying $V_2O_5$ molar ratio by increasing 0.02mole to the formula $Mg_1-xTi_2-xM_{2x}O_5$(x = 0.01~0.09 mole). Synthesized pigments were analyzed by XRD, Raman spectroscopy and UV-vis. When $V_2O_5$ was doped from 0.01 to 0.05 mole, single phase of Karrooite was observed at temperature $1300^{\circ}C$ and soaking time 4h by Raman spectroscopy. However, it was found that excess $VO_2$ peak appeared with 0.07 and 0.09 mole of $V_2O_5$ doped to $MgTi_2O_5$. This result indicated that the maximum limit of solid solution is 0.05 mole $V_2O_5$. Karrooite pigments were applied as a ceramic pigment to achieve brown colors in lime magnesia glaze and lime barium graze at both of oxidation and reduction atmosphere. CIE color coordinates are $L^*$ = 40.34, $a^*$ = 9.94, $b^*$ = 21.40 in lime magnesia glaze.