• Development and Reproduction
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• v.12 no.1
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• pp.107-112
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• 2008

To investigate the $C_{21}$-steroids produced from maturating oocytes in the longchin goby, Chasmichthys dolichognathus, the oocytes ($0.74{\sim}0.97\;mm$) were incubated with radiolabeled $17{\alpha}$-hydroxyprogesterone ($^3H-17{\alpha}OHP$) for 24 hours. The resulting metabolites were analyzed by thin layer chromatography and identified by gas chromatography-mass spectrometry. Two $C_{21}$-steroids, $17{\alpha}$-hydroxy, $20{\alpha}$-dihydroprogesterone ($17{\alpha}20{\alpha}P$) and $17{\alpha}$-hydroxy, $20{\beta}$-dihydroprogesterone ($17{\alpha}20{\beta}P$), were converted from $^3H-17{\alpha}OHP$ in the maturing oocytes. These two main metabolites were detected at 0.80 mm diameter oocytes or greater. In addition, the effects of these metabolites on in vitro germinal vesicle breakdown (GVBD) were tested. The sensitivity of oocytes to the induction of GVBD was greater at $17{\alpha}20{\beta}P$ than $17{\alpha}20{\alpha}P$. This result showed that $17{\alpha}20{\beta}P$ is a major maturation inducing steroid (MIS) in longchin goby, suggesting $17{\alpha}20{\alpha}P$ may play a role in regulating the oocyte maturation process.

• Development and Reproduction
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• v.5 no.2
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• pp.101-106
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• 2001

Present study was aimed to verify the role of insulin and TNF-$\alpha$ in development of preimplantation embryos. Mouse morula were cultured for 40 hr in the presence or absence of insulin(400 ng/ml) and TNF-$\alpha$ (50 ng/ml). The morphological development, cell number of blastomeres per blastocyst, and mitogen activated protein kinase(MAPK) activity were examined. The developmental rate and cell number per embryo were the highest in insulin treatment group and the lowest in TNF-$\alpha$ treatment group. There was no significant difference in developmental rate between control and insulin plus TNF-$\alpha$ group. Taken together, it suggested that TNF-$\alpha$ impaired embryonic development and that insulin rescued developmental impairment imposed by TNF-$\alpha$. In blastocysts, insulin treatment significantly increased MAPK activity. TNF-$\alpha$ decreased the MAPK activity in a concentration-dependent manner. In the TNF-$\alpha$(50 ng/ml) -primed embryos, activation of MAPK by insulin was attenuated. In conclusion, these results suggest that there was a cross talk between insulin and TNF-$\alpha$ by means of activation of MAPK in preimplantation embryos and that insulin might rescue damage of embryos exposed to TNF-$\alpha$.

• Journal of the Korean Chemical Society
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• v.22 no.5
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• pp.334-339
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• 1978

The hydrolysis of ${\alpha}$-bromophenylacetamide in the acidic media has been studied. The reactions in sulfuric acid and p-toluenesulfonic acid afforded mainly mandelic acid ; on the other hand, in hydrochloric acid ${\alpha}$-chlorophenylacetic acid was the main product. In either case, it was difficult to obtain ${\alpha}$-bromophenylacetic acid without concomittant formation of mandelic acid and ${\alpha}$-chlorophenylacetic acid respectively from the hydrolysis of ${\alpha}$-bromophenylacetamide. Mandelic acid and ${\alpha}$-chlorophenylacetic acid were obtained in good yields (86, 95 %) in sulfuric and hydrochloric acid respectively; the reactions are therefore potentially useful processes for obtaining them.

• YAKHAK HOEJI
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• v.33 no.4
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• pp.237-240
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• 1989

A new synthetic method for tiaprofenic acid, which is a potent anti-inflammatory agent, was described. Friedel-Crafts reaction of thiophene with ethyl ${\alpha}-chloro-{\alpha}-(methylthio)$ acetate (1) gave ethyl ${\alpha}-methylthio-2-thiopheneacetate$ (3). Ethyl ${\alpha}-methyl-2-thiopheneacetate$ (5) was prepared by treatment of (3) with NaH and MeI, followed by desulfurization with zinc dust-acetic acid of the resultant ethyl ${\alpha}-methyl-{\alpha}-methylthio-2-thiopheneacetate$ (4). Tiaprofenic acid (7) could be easily synthesized by benzoylation of (5) and hydrolysis of the resultant ethyl $5-benzoyl-{\alpha}-methyl-2-thiopheneacetate$ (6).

• Bulletin of the Korean Mathematical Society
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• v.59 no.3
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• pp.697-707
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• 2022

It is well known that the continued fraction expansion of ${\sqrt{d}}$ has the form $[{\alpha}_0,\;{\bar{{\alpha}_1,\;{\ldots},\;{\alpha}_{l-1},\;2_{{\alpha}_0}}]$ and ${\alpha}_1,\;{\ldots},\;{\alpha}_{l-1}$ is a palindromic sequence of positive integers. For a given positive integer l and a palindromic sequence of positive integers ${\alpha}_1,\;{\ldots},\;{\alpha}_{l-1},$ we define the set $S(l;{\alpha}_1,\;{\ldots},\;{\alpha}_{l-1})\;:=\;\{d{\in}{\mathbb{Z}}{\mid}d>0,\;{\sqrt{d}}=[{\alpha}_0,\;{\bar{{\alpha}_1,\;{\ldots},\;{\alpha}_{l-1},\;2_{{\alpha}_0}}],\;where\;{\alpha}_0={\lfloor}{\sqrt{d}}{\rfloor}\}.$ In this paper, we completely determine when $S(l;{\alpha}_1,\;{\ldots},\;{\alpha}_{l-1})$ is not empty in the case that l is 4, 5, 6, or 7. We also give similar results for $(1+{\sqrt{d}})/2.$ For the case that l is 4, 5, or 6, we explicitly describe the fundamental units of the real quadratic field ${\mathbb{Q}}({\sqrt{d}}).$ Finally, we apply our results to the Mordell conjecture for the fundamental units of ${\mathbb{Q}}({\sqrt{d}}).$

• Journal of the Korean Mathematical Society
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• v.33 no.1
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• pp.47-55
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• 1996

Let $0 < \alpha < 2$ and let $T_\alpha (\theta) = \alpha tan(\theta/2)$. $T_\alpha$ has an attractive fixed point at $\theta = 0$. We denote by $C(\alpha)$ the set of points in $I = [-\pi, \pi]$ which are not attracted to $\theta = 0$ by the succesive iterations of $T_\alpha$. That is, $C(\alpha)$ is the set of points in I where the dynamics of $T_\alpha$ is chaotic.

• YAKHAK HOEJI
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• v.29 no.2
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• pp.62-69
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• 1985

The isomeric intermediates, $3{\alpha}$and $3{\beta}-amino-5{\alpha}-cholestane required for the synthesis of N-nitrosoureas, N-(2-chloroethyl)-N-nitrosocarbamoyl-$3{\alpha}-amino-5{\alpha}$-cholestane (9), N-methyl-N-nitrosocarbamoyl-3${\alpha}-amino-5{\alpha}-cholestane$ (10), N-(2-chloroethyl)-N-nitrosocarbamoyl-$3{\beta}-amino-5{\alpha}-cholestane$: (7), and N-methyl-N-nitrosocarbamoyl-$3{\beta}-amino-5{\alpha}-cholestane$ (8) were obtained through the $LiAlH_{4}$ reduction of $5{\alpha}$-cholestan-3-one oxime, followed by the chromatographic separation: the assignment of the stereochemistry of both isomers were based on the shape and chemical shift of $C_{3}$-proton resonances on their NMR spectra and on the elution mobility on the TLC. The urea intermediates, N-(2-chloroethyl) carbamoyl-3.alpha.-amino-5.alpha.-cholestane (13), N-methylcarbamoyl-$3{\alpha}-amino-5{\alpha}-cholestane$ (14), N-(2-chloroethyl) carbamoyl-$3{\beta}-amino-5{\alpha}-cholestane (11) and N-methyl-$3{\beta}-amino-5{\alpha}$-cholestane (12) were prepared by the treatment of each isomers ($3{\alpha}$-amino-and $3{\beta}-amino-5{\alpha}$-cholestane) with alkyl isocyanates in anhydrous $CHCl_{3}$, and the corresponding nitrosoureas, 7-10 were obtained by the nitrosation of the ureas, 11-14, with AcOH (or HCOOH)/$NaNO_{2}$ in ice-cold condition. The inhibitory activity of the nitrosoureas, 7-10, and their intermediates, 12-14 towards the growth of L1210 murine leukemia cells, were examined. Among them, the compounds 9 and 10 exhibited high activity having $ED_{50}$ to be 5.5g/ml and 6.1g/ml, respectively.

• Polymer(Korea)
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• v.38 no.4
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• pp.411-416
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• 2014

Due to the polar characteristics of silica compared to carbon black, the degree of silica dispersion, which affects the mechanical properties of rubber compounds, is an important issue. Wolff first introduced the in-rubber structure of particles (${\alpha}_F$) to express the structure development in the compounds; however, with the introduction of bifunctional silanes, his theory could not explain the 3-dimensional network structure of the compounds. Later his theory was expanded to express the composite interaction parameter (in-rubber structure of the compound) (${\alpha}_C$), which included Wolff's filler-filler interaction parameter (${\alpha}_F$), however, there was no reported experimental result proving the theory. This research first experimentally expressed the in-rubber structure of the compound ${\alpha}_C$ (= ${\alpha}_F+{\alpha}_{FP}$(filler-silane-rubber interaction parameter) + ${\alpha}_P$ (rubber-rubber interaction parameter)) upon mono- and bifunctional silane treated silica filled natural rubber (NR) compounds. Using different structure silanes, i.e. PTES, OTES, TESPD, and TESPT, the ${\alpha}_C$ value of each compound was measured and calculated. The ${\alpha}_C$ value of TESPT treated silica filled compound was 1.64, which composed of ${\alpha}_F$ (0.99), ${\alpha}_{FP}$ (0.31), and ${\alpha}_P$ (0.34).

• Journal of the Korean Chemical Society
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• v.23 no.5
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• pp.307-313
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• 1979

Seven new hydrazine derivatives were prepared from N-Aryllsufonylbenzimidoyl chloride. These were: ${\beta}-({\alpha}-Benzenesulfonamidobenzal)hydrazine\;(II),\;{\beta}-({\alpha}-Benzenesulfonamidobenzal)dimethylmethylenehydrazine\;(III),\;{\beta}-({\alpha}-Benzenesulfonamidobenzal)phenylhydrazine\;(VII),\;{\beta}-({\alpha}-Benzenesulfonamidobenzal)-4-nitrophenylhydrazine\;(VIII),\;{\beta}-({\alpha}-Benzenesulfonamidobenzal)-2,4-dinitrophenylhydrazine\;(IX),\;{\beta}-({\alpha}-Benzenesulfonamidobenzal)dimethylhydrazine\;(X),\;{\beta}-({\alpha}-Benzenesulfonamidobenzal)-p-methylphenylhydrazine\;(XI)$. The structure of these derivatives were identified by elemental analysis, spectral data and other chemical methods. In general, it was found that the yields of these reactions were significantly improved in polar solvent and by the electron attracting substituents in phenylhydrazine.

• The Zoological Society Korea : Newsletter
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• v.18 no.2
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• pp.38-44
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• 2001

전위활성화 칼슘통로를 통한 칼슘이온의 세포 내 유입은 근육수축, 시냅스 전달, 호르몬 분비, 효소의 활성도 및 유전자 발현을 조절한다. 이와 같이 중요한 생리적 기능을 조절하기 때문에 칼슘통로를 대상으로 한 다방면의 연구가 과거 20년간 활발히 진행되어 왔다 칼슘통로는 $\alpha$1, $\alpha$2-$\delta$, $\beta$로 구성되어 있으며, 이 중 $\alpha$1은 칼슘통로의 일반적 특성을 나타내는 기본 구조체이며, $\alpha$2-$\delta$와 $\beta$는 $\alpha$1을 조절하는 보조 기능을 한다. 지금까지 10개의 $\alpha$1 subunits(L-형: $\alpha$1S, $\alpha$1C, $\alpha$1D, $\alpha$1F; non-L-형: $\alpha$1A, a1B, $\alpha$1E; T-형: $\alpha$1G, $\alpha$1H, $\alpha$1I), 4종류의 $\beta$ subunits, 3 종류의 $\alpha$2-$\delta$ subunits가 클로닝되었으며, 이들 클론을 이용한 분자 수준에서의 연구가 활발히 이루어지고 있다. 본 논단에서는 칼슘통로의 구조, 기능 및 조절에 대한 연구가 전기생리학적, 분자생물학적 및 약리학적 방법을 사용하여 어떻게 수행되어왔는지 살펴보고, 최근 연구성과에 대해서도 소개하고자 한다.