• Molecules and Cells
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• 제26권4호
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• pp.409-414
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• 2008

The cholesteryl ester transfer protein (CETP), a key player in cholesterol metabolism, has been shown to promote the transfer of triglycerides from very low density lipoprotein (VLDL) and low density lipoprotein (LDL) to high density lipoprotein (HDL) in exchange for cholesterol ester. Here we demonstrate that farnesoid X receptor ${\alpha}$ ($FXR{\alpha}$; NR1H4) down-regulates CETP expression in HepG2 cells. A $FXR{\alpha}$ ligand, chenodeoxycholic acid (CDCA), suppressed basal mRNA levels of the CETP gene in HepG2 cells in a dose-dependent manner. Using gel shift and chromatin immunoprecipitation (ChIP) assays, we found that $FXR{\alpha}$ could bind to the liver X receptor ${\alpha}$ ( $LXR{\alpha}$; NR1H3) binding site (LXRE; DR4RE) located within the CETP 5' promoter region. $FXR{\alpha}$ suppressed $LXR{\alpha}$-induced DR4RE-luciferase activity and this effect was mediated by a binding competition between $FXR{\alpha}$ and $LXR{\alpha}$ for DR4RE. Furthermore, the addition of CDCA together with a $LXR{\alpha}$ ligand, GW3965, to HepG2 cells was shown to substantially decrease mRNA levels of hepatic CETP gene, which is typically induced by GW3965. Together, our data demonstrate that $FXR{\alpha}$ down-regulates CETP gene expression via binding to the DR4RE sequence within the CETP 5' promoter and this $FXR{\alpha}$ binding is essential for $FXR{\alpha}$ inhibition of $LXR{\alpha}$-induced CETP expression.

• 약학회지
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• 제39권4호
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• pp.433-437
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• 1995

Optically pure(-)-and (+)-$\alpha$-hydroxy-$\alpha$-(p-chlorobiphenyl)acetic acids were prepared. The racemate was synthesized through three steps. By condensation of p-cnorobiphenyl with diethyl ketomalonate in the presence of SnCl$_{4}$, diethyl $\alpha$-hydroxy-$\alpha$-(p-chlorobiphenyl)malonate (1) was formed and subsequently ($\pm$)-$\alpha$-hydroxy-$\alpha$-(p-chlorobiphenyl)acetic acid (3) was obtained through hydrolysis and decarboxylation. For the separation of the racemate the classical resolution method, derivatization of a racemate by reaction with an optically pure compound was employed. In this case the optically pure compound were [R]-(+)-$\alpha$-methylbenzylamine and [S]-(-)-$\alpha$-methylbenzylamine. Diastereomeric salts between acids and bases could be easily separated by crystallization in absolute ethanol.

• 한국세라믹학회지
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• 제25권2호
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• pp.143-153
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• 1988

김천규석으로부터 합성한 질화규소와 시약급의 AIN과 $Y_2O_3$를 출발원료로 하여 $Si_3N_4-0.1Y_2O_3-0.9AIN$의 tie line에서 X=0.6, 0.4(금속고용량)인 조성으로부터 AIN 의 양을 감소시킨 조성과 $Y_2O_3$를 증가시키는 조성으로 1750~1800도에서 소결시켜 부분 안정화 $\alpha$-Sialon을 제조하였다. $\alpha$-Sialon 생성에는 $Y_2O_3$ 첨가량보다 AIN 첨가량에 밀접하게 관련되며 AIN은 $\beta$단위격자 보다 $\alpha$ 단위격자로 우선적으로 고용되었으며 $Y_2O_3$가 과잉으로 첨가된 조성에서는 melillite 형성과 입자 조대화 및 $\alpha$-Sialon의 분배로 인하여 yttrium silicide 와 금속 Si를 형성하였으며 기계적 물성은 저하하였다. 본 실험에서 얻은 기계적 물성의 최고 값은 모두 1780도에서 얻어졌으며 그 값은 꺽임강도 723MPa, 파괴 인성 4.5MN/m^3/2, 경도 19.3GPa이었다.

• 한국미생물·생명공학회지
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• 제1권1호
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• pp.43-50
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• 1973

34종의 Hexachlorophene유도체가 합성되었으며 그 각각의 화합물에 대하여 항균성시험이 행해졌다. 검정균은 세종류의 세균과 무좀균(백성균)을 포함한 5종류의 진균류이다. 시험결과는 1. 2,2'-Methylene bis [$\alpha$-(3,4,6-trichlorophenoxy)-$\beta$-(N,N-diethylamino) propionic acid] 및 2,2'-methylene bis [$\alpha$-3,4,6-trichlorophenoxy)-$\beta$-(N,N-dimethylamino) propionic acid] 는 Sta. aureus와 B.subtilis에 대해 강한 항균작용을 나타냈다. 2. 2,2'-methylene bis [$\alpha$-(3,4,6-trichlorophenoxy)-$\beta$-(m-hydroxy-p-carbozyphenylarnino ) propionic acid]는 특히 진균류의 생장저해작용이 강하며 Trichophyton rubrum 및 Microsporum gypseum에는 2 $\mu\textrm{g}$/$m\ell$의 농도에서 항균성을 가지며, Epidermophyton floccosum Aspergillus niger 및 Aspergillus oryzae에 대해서는 1 $\mu\textrm{g}$/$m\ell$의 농도에서 항균성을 나타냄으로서 Hexachlorophene 항균성의 10배 내지 50배의 항균력을 가진다. 3. 34종류의 합성물질중 원 Hexachlorophene에 비해 5종류의 진균류에 대해 부분적으로나마 강한 항균력을 나타내는 물질은 23종류였고 3종류의 세균에 대해선 13종류였다.

• Kyungpook Mathematical Journal
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• 제48권4호
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• pp.721-727
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• 2008

Let $W_{\alpha}$ be a weighted shift with positive weight sequence ${\alpha}=\{\alpha_i\}_{i=0}^{\infty}$. The semi-cubical hyponormality of $W_{\alpha}$ is introduced and some flatness properties of $W_{\alpha}$ are discussed in this note. In particular, it is proved that if ${\alpha}_n={\alpha}_{n+1}$ for some $n{\geq}1$, ${{\alpha}_{n+k}}={\alpha}_n$ for all $k{\geq}1$.

• 폴리머
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• 제32권4호
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• pp.366-371
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• 2008

The controlled/living cationic polymerization of $\alpha$-methylstyrene (${\alpha}MeSt$) and sequential block copolymerization of isobutylene (IB) with ${\alpha}MeSt$ were achieved using 2-chloro-2,4,4-trimethylpentane (TMPCl)/titanium tetrachloride ($TiCl_4$)/titanium isopropoxide ($Ti(OiPr)_4$)/2,6-ditert-butylpyridine (DtBP) initiating system in $CH_3Cl$/hexane(50/50 v/v) solvent mixture at $-80^{\circ}C$. The polymerization rate decreased with increasing $[Ti(OiPr)_4]/[TiCl_4]$ ratio in the homopolymerization of ${\alpha}MeSt$. The effects of $[Ti(OiPr)_4]/[TiCl_4]$ ratios and $PIB^+$ molecular weight on the polymerization rate and blocking efficiency were also investigated. Well-defined poly(isobutylene-b-$\alpha$-methylstyrene)s were demonstrated by $^1H$-NMR and triple detection SEC; refractive index (RI), multiangle laser light scattering (MALLS) and ultraviolet (UV) detectors. Blocking efficiencies for the poly(isobutylene-b-$\alpha$-methylstyrene)s of almost 100% were obtained when ${\alpha}MeSt$ was induced by PIB's of $M_n\;{\geq}\;41000$ at $[Ti(OiPr)_4]/[TiCl_4]=1$. Differential scanning calorimetry (DSC) of the block copolymers showed two glass transition temperatures, thereby demonstrating microphase separation.

• 호남수학학술지
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• 제40권1호
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• pp.47-59
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• 2018

We define the $e^{\alpha}_1e^{\alpha}_3$-isotropic Smarandache curves of type-1 and type-2, the $e^{\alpha}_1e^{\alpha}_2e^{\alpha}_3$-isotropic Smarandache curve, and the $e^{\alpha}_1e^{\alpha}_2e^{\alpha}_4$-isotropic Smarandache curves of type-1 and type-2. Then we examine these kinds of isotropic Smarandache curve according to Cartan frame in the complex 4-space $\mathbb{C}^4$ and give some differential geometric properties of these Samarandache curves.

• 대한의생명과학회지
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• 제15권1호
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• pp.101-103
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• 2009

The hepatocyte nuclear factor-$4{\alpha}$ (HNF-$4{\alpha}$), transcription factor involved in the regulation of serum lipid and glucose levels, has recently been reported to be associated with type 2 diabetes. Therefore, we investigated the genotype for the rs1884614 of HNF-$4{\alpha}$ gene in Korean population and compared genotype of patients with control group. 100 patients (Male 63, Female 37), who previously underwent type 2 diabetes (T2DM) and 100 controls (Male 36, Female 64) participated in this study. According to our present study there was no association between rs1884614 polymorphism in HNF-$4{\alpha}$ gene and T2DM in Koreans although other reports showed that HNF-$4{\alpha}$ polymorphisms might be associated with the pathogenesis of T2DM in Pima Indians et al. We assume that this finding should contribute to understanding of type 2 diabetes in Korean population in detail at genetic level.

• 약학회지
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• 제51권1호
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• pp.56-62
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• 2007

Twelve epoxy and hydroxydiosgenin derivatives (DI-1${\sim}$DI-12) were synthesized from diosgenin (25(R)-5-spirosten-3${\beta}$-ol). Diosgenin was epoxidized with m-chloroperoxybenzoic acid (mCPBA) to oxidize 25(R)-4${\alpha}$,5${\alpha}$-epoxyspirostane (DI-1). Diosgenin was reacted with DDQ to form 25(R)-1,4,6-spirostatrien-3-one (DI-2), which was treated with 30% H$_2$O$_2$ to give 25(R)-1${\alpha}$,2${\alpha}$-epoxy-4,6-spirostadien-3-one (DI-3) and treated with mCPBA to form 25(R)-6${\alpha}$,7${\alpha}$-epoxy-1,4-spirostadien-3-one (DI-7), respectively. DI-3 was reduced with NaBH$_4$ to afford 25(R) -1${\alpha}$,2 ${\alpha}$-epoxy-4,6-spirostadien-3${\beta}$-ol(DI-4) and reacted with Li metal in absolute ethanol to form 25(R)-2-ethoxy-1,4,6-spirostatrien-3-one (DI-5). DI-7 was reduced with NaBH$_4$ to produce 25(R)-3${\beta}$,7${\alpha}$-dihydroxy-4-spirostene (DI-8) and treated with Li metal in liquid ammonia to produce 25(R)-7${\alpha}$-hydroxy-4-spirosten-3-one (DI-9). DI-2 was reduced with NaBH$_4$ to form 25(R) -4,6-spirestadien-3${\beta}$-ol(DI-10), which was stirred with 30% H$_2$O$_2$ to synthesize 25(R)-4,6-spirostadien-3-one (DI-11) and reacted with mCPBA to give 25(R)-4${\beta}$,5${\beta}$ -epoxy-6-spirosten-3${\beta}$-ol (DI-12), respectively. The antinociceptive effects of synthesiz ed compounds were measured by hot plate method and compound DI-7 signifcantly exhibited antinociceptive effect. DI-2 decreased the serum triglyceride and total cholesterol levels in poloxamer P-407 injected rat.

• 농업과학연구
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• 제18권1호
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• pp.49-73
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• 1991

발아대두 $\alpha$-galactosidase와 Aspergillus niger가 생산하는 $\alpha$-galactosidase의 효소학적 성질을 비교하기 위하여 대두 발아 중의 $\alpha$-galactosidase활성 및 소당류의 함량변화를 측정하였고, 대두 발아 과정 중 활성이 가장 강할때에 추출한 $\alpha$-galactosidase 및 Aspergillus niger를 밀기울 배양하였을 때 생성되는 $\alpha$-galactosidase를 염석, 이온교환 크로마토그래피 및 겔여과 등을 사용하여 정제한 후 정제효소의 이화학적 및 효소학적 성질을 측정, 비교하여 다음과 같은 결과를 얻었다. 1. 대두 $\alpha$-galactosidase의 활성은 대두를 $25^{\circ}C$에서 120시간 발아시켰을 때 가장 높았으며, 대두 중의 raffinose는 96시간, stachyose는 120시간 발아시켰을 때 완전히 분해되었다. 2. Aspergillus niger를 밀기울배지에서 $30^{\circ}C$, 4일간 배양했을 때 $\alpha$-galactosidase 활성이 최고에 달하였다. 3. 대두 $\alpha$-galactosidase는 황산암모늄 염석, DEAE-Cellulose 및 DEAE-Sephadex A-50 이온교환 크로마토그래피, Sephadex G-l50 겔여과 등에 의하여 6.6배까지 정제되었으며 그의 비활성이 825U/mg protein, 수율 2.5%에 달하였고, Aspergillus niger의 $\alpha$ -galactosidase는 23.7배까지 정제되었으며 그의 비활성이 1,229U/mg protein, 수율 14%에 달하였다. 4. 정제된 대두 및 Aspergillus niger의 $\alpha$-galactosidase는 HPLC, PAGE 및 SDS-PAGE에 의해서 순도가 확인되었다. 5. 정제효소의 이화학적 성질 1) Aspergillus niger의 $\alpha$-galactosidase는 periodic acid schiff 염색에 의하여 당단백질임이 확인되었다. 2) 대두 $\alpha$-galactosidase의 등전점은 pH4.8이었고, 분자량이 30,000인 monomer이었으나, Aspergillus niger의 $\alpha$-galactosidase는 등전점이 pH4.6이었고 분자량은 112,000이었으며 분자량 28,000인 monomer 4개로 구성된 tetramer이었다. 3) 대두 및 Aspergillus niger $\alpha$-galactosidase의 활성에 관여하는 아미노산은 diethyl pyrocarbonate에 의한 화학 수식에 의하여 histidine임이 확인되었다. 4) 대두 $\alpha$-galactosidase의 활성은 2-mercaptoethanol과 L-cysteine에 의하여 약간 저해되었다. 6. 정제효소의 효소학적 성질 1) 대두 $\alpha$-galactosidase의 최적 작용 pH는 pH6.0, 최적 작용온도는 $40^{\circ}C$이었고, Aspergillus niger $\alpha$-galactosidase 각각 pH6.5 및 $40^{\circ}C$이었다. 2) 대두 및 Aspergillus niger의 $\alpha$-galactosidase는 $45^{\circ}C$이하에서 비교적 안정하였으나 $60^{\circ}C$에서 10분 처리시 대두 $\alpha$-galactosidase는 25%, Aspergillus niger $\alpha$-galactosidase는 46%의 잔존활성을 나타내었다. 3) 대두 $\alpha$-galactosidase는 pH5.5~6.5, Aspergillus niger의 $\alpha$-galactosidase는 pH6.0~7.0에서 매우 안정하였다. 4) 대두 및 Aspergillus niger의 $\alpha$-galactosidase간에 기질 특이성상의 차이가 없었으며, stachyose보다 raffinose를 잘 분해하였고, gaIactose는 양효소의 활성을 저해하였다. 5) 대두 $\alpha$-galactosidase의 P-nitrophenyl-$\alpha$-gaIactopyranoside, raffinose 및 stachyose에 대한 Km값은 각각 5.3mM, 50.0mM 및 55.5mM이 었고, Aspergillus niger $\alpha$-galactosidase에 있어서는 각각 5.0mM, 37.0mM 및 55.5mM이었다. 6) 대두 $\alpha$-galactosidase의 p-nitrophenyl-$\alpha$-d-gaIactopyranoside에 대한 활성화 에너지는 13.024Kcal/mole, $Q_{10}$값은 2.0이 었으며, Aspergillus niger의 $\alpha$-galactosidase는 각각 8.515Kcal/mole 및 1.38이었다.