• Bulletin of the Korean Chemical Society
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• v.26 no.6
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• pp.935-938
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• 2005

Nucleophilic addition reactions of benzylamines (BA; $XC_6H_4CH_2NH_2$) to $\alpha-cyano-\beta$-phenylacrylamides (CPA; $YC_6H_4CH=C(CN)CONH_2$) have been investigated in acetonitrile at 25.0 ${^{\circ}C}$. The rate is first order with respect to BA and CPA and no base catalysis is observed. The addition of BA to CPA occurs in a single step in which the addition of BA to $C_{\beta}$ of CPA and proton transfer from BA to $C_{\alpha}$ of CPA take place concurrently with a four-membered cyclic transition state structure. The magnitude of the Hammett ($\rho_X$) and Bronsted ($\beta_X$) coefficients are rather small suggesting an early tansition state (TS). The sign and magnitude of the crossinteraction constant, $\rho_XY$ (= −D0.26), is comparable to those found in the normal bond formation processes in the $S_N2$ and addition reactions. The normal kinetic isotope effect ($k_H/k_D\;{\gt}$ 1.0) and relatively low ${\Delta}H^{\neq}$ and large negative ${\Delta}S^{\neq}$ values are also consistent with the mechanism proposed.

• Journal of Life Science
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• v.23 no.5
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• pp.650-656
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• 2013

Endothelial protein C receptor (EPCR) plays a pivotal role in augmenting Protein C activation through the thrombin-thrombomodulin complex. EPCR activity is markedly changed by ectodomain cleavage and released as the soluble protein (sEPCR). EPCR shedding is mediated by tumor necrosis factor-${\alpha}$ converting enzyme (TACE). Lycopene found in tomatoes and tomato products has anti-oxidant, anti- cancer and anti-inflammatory effects. However, little is known about the effects of lycopene on EPCR shedding. We investigated this issue by monitoring the effects of lycopene on the phorbol-12-myristate 13-acetate (PMA), tumor necrosis factor (TNF)-${\alpha}$, interleukin (IL)-$1{\beta}$ and on the cecal ligation and puncture (CLP)-mediated EPCR shedding. Data showed that lycopene potently inhibited the PMA, TNF-${\alpha}$, IL-$1{\beta}$ and CLP-induced EPCR shedding by suppressing TACE expression. Furthermore, lycopene reduced PMA-stimulated phosphorylation of p38, extracellular regulated kinases (ERK) 1/2 and c-Jun N-terminal kinase (JNK). Given these results, lycopene should be viewed as a candidate therapeutic agent for the treatment of various severe vascular inflammatory diseases via inhibition of the EPCR shedding.

• Journal of the Korean Ceramic Society
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• v.41 no.3
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• pp.253-258
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• 2004

Non-aggregated nanoscale $\alpha$-Al$_2$O$_3$ powders were prepared successfully by polyacrylamine (PAA) gel method. The method was very simple and polymer network inhibited the aggregate of $\alpha$-Al$_2$O$_3$ powders. In this investigation, nanoparticles of $\alpha$-Al$_2$O$_3$ with a diameter of about 8-15 nm were fabricated by calcining the gel precusors with various concentrations of aluminum sulfate, acrylamide and N,N'-methylene-bis-acrylamide (BIS) in air at 110$0^{\circ}C$ for 2 h. The molar ratio of aluminum sulfate to acrylamide did not have any influence on the size of particles. On the other hand, as the molar ratio of BIS to acrylamide increased, the size of nanoparticles decreased.

• Bulletin of the Korean Chemical Society
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• v.35 no.5
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• pp.1365-1374
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• 2014

Thirteen analogs of tridecapeptide ${\alpha}$-factor (WHWLQLKPGQPMY) of Saccharomyces cerevisiae with C- or N-terminal Trp extension and isosteric replacement by Aib at position 8 and 11, Trp at position 13, D-Ala at position 9, and Orn and Glu at position 6 were synthesized and assayed for their biological activity. Receptor binding assay was carried out using our newly developed spectrophotometric method with detector peptide 14. C- or N-terminal extended analogs, ${\alpha}$-factor-$[Trp]_n$ (n =1-5) 1-5 and $[N-Trp]_1$-${\alpha}$-factor 6, were all less active than native ${\alpha}$-factor and gradual decreases in both activity and receptor affinity were observed with greater Trp extension. Trp-substituted analog at position 13, $[Trp^{13}]{\alpha}$-factor 7, exhibited about 2-fold reductions in both activity and receptor affinity. Aib-substituted analogs, $[Aib^8]{\alpha}$-factor 8 and $[Aib^{11}]{\alpha}$-factor 9, showed 5- to 10-fold reduction in activity as well as 3-fold reduction in receptor affinity compared to native ${\alpha}$-factor. $[Orn^6]{\alpha}$-factor 10 demonstrated strong potency with a 7.0-fold increase in halo activity as well as 1.8-fold increase in receptor affinity compared to native ${\alpha}$-factor. For two double substituted analogs, [$Glu^6,{\small{D}}-Ala^9$]${\alpha}$-factor 12 showed the slightly decreased potency in halo activity compared to analog 10, whereas [$Orn^6,{\small{D}}-Ala^9$]${\alpha}$-factor 11 exhibited 15-fold higher halo activity as well as nearly 3-fold higher receptor affinity compared to native ${\alpha}$-factor.

• YAKHAK HOEJI
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• v.51 no.1
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• pp.35-43
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• 2007

To investigate the immunomodulatory roles of cyclic AMP (CAMP) on macrophage- and T lymphocyte-mediated immune responses, CAMP elevating agents were employed and carefully re-examined under the activation conditions of the cells. Various inhibitors tested dose-dependently blocked tumor necrosis factor (TNF)-${\alpha}$ production with IC$_{50}$ values ranged from 0.04 to 300 ${\mu}$M. Of the inhibitors, cAMP-elevating agents showed lower cytotoxicity assessed by lactate dehydrogenase (LDH) release, suggesting less toxic and more selective. In particular co-treatment of dbcAMP with a protein kinase C inhibitor staurosporine displayed the synergistic inhibition of TNF-${\alpha}$ production. The modulatory effect of dbcAMP on TNF-${\alpha}$ and nitric oxide (NO) was significantly affected by treatment time of dbcAMP. Thus, post-treatment of dbcAMP (three hours before LPS) abrogated dbcAMP's inhibitory activity and rather enhanced TNF-${\alpha}$ level up to 60%. In contrast, additional NO production was shown at the co-treatment of dbcAMP with LPS. Unlike simultaneous treatment of phorbol 12-myristate 13-acetate (PMA) and interferon (IFN)-${\gamma}$co-treatment, the combination of dbcAMP with other NO-inducing stimuli did not show drastic overproduction of NO. cAMP elevating agents also diminished splenocyte proliferation stimulated by concanavalin (Con) A, phytohemaglutinin A (PHA) and lipopolysaccharide (LPS). In addition, dbcAMP but not rolipram strongly suppressed CD8$^+$ T cells (CTLL-2). Finally, cAMP elevating agents were differentially involved in regulating CD98-mediated cell-cell adhesion. Thus, dbcAMP and rolipram significantly enhanced the cell-cell adhesion, whereas forskolin blocked. Therefore, our results suggest that CAMP elevating agents participate in various immune responses mediated by macrophages and T cells with a different fashion depending on cellular environments and activation signals.

• Journal of the Korean Mathematical Society
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• v.54 no.4
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• pp.1121-1148
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• 2017

Go is an ancient game of great complexity and has a huge following in East Asia. It is also very rich mathematically, and can be played on any graph, although it is usually played on a square lattice. As with any game, one of the most fundamental problems is to determine the number of legal positions, or the probability that a random position is legal. A random Go position is generated using a model previously studied by the author, with each vertex being independently Black, White or Uncoloured with probabilities q, q, 1 - 2q respectively. In this paper we consider the probability of legality for two scenarios. Firstly, for an $N{\times}N$ square lattice graph, we show that, with $q=cN^{-{\alpha}}$ and c and ${\alpha}$ constant, as $N{\rightarrow}{\infty}$ the limiting probability of legality is 0, exp($-2c^5$), and 1 according as ${\alpha}$ < 2/5, ${\alpha}=2/5$ and ${\alpha}$ > 2/5 respectively. On the way, we investigate the behaviour of the number of captured chains (or chromons). Secondly, for a random graph on n vertices with edge probability p generated according to the classical $Gilbert-Erd{\ddot{o}}s-R{\acute{e}}nyi$ model ${\mathcal{G}}$(n; p), we classify the main situations according to their asymptotic almost sure legality or illegality. Our results draw on a variety of probabilistic and enumerative methods including linearity of expectation, second moment method, factorial moments, polyomino enumeration, giant components in random graphs, and typicality of random structures. We conclude with suggestions for further work.

• Proceedings of the Ginseng society Conference
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• 1993.09a
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• pp.74-83
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• 1993

In an attempt toward the synthesis of the difficulty accessible ginseng saponins the four dammarane glycosides identical to the natural $ginsenosides-Rh_2,$ - F2, compound K and chikusetsusaponin - LT8 have been prepared from betulafolienetriol(=dammar-24-ene-$3{\alpha},12{\beta}\;20(S)-triol).\;3-O-{\beta}-D-Glucopyranoside$ of 20(S) - protopanaxadiol $(=ginsenoside-Rh_2)$ have been obtained by the regio - and stereoselective glycosylation of the $12-O-acetyldammar-24-ene-3{\beta},\;12{\beta},$ 20(S)-triol. The 12-ketoderivative of 20(S)-protopanaxadiol has been used as aglycon in synthesis of chikusetsusaponin - LT8. Attempted regio - and stereoselective glycosylation of the less reactive tertiary C - 20 - hydroxyl group in order to synthesize the $20-O-{\beta}-D-glucopyranoside$ of 20(S)-protopanaxadiol(=compound K) using 3, 12 - di - O - acetyldammar - 24 - ene - $3{\beta},12{\beta},20(S)$-trial as aglycon was unsuccessful. Glycosylation of 3, 12 - diketone of betulafolienetriol followed by $NaBH_4$ reduction yielded the $20-O-{\beta}-D-glucopyranoside\;of\;dammar-24-ene-3{\beta},12{\alpha},$ 20(S)-triol, the $12{\alpha}-epimer$ of 20(S) - protopanaxadiol. Moreover, a number of semisynthetic ocotillol - type glucosides, analogs of natural pseudoginsenosides, have been prepared.

• Korean Journal of Microbiology
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• v.33 no.2
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• pp.86-91
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• 1997

Pseudomonas sp. DJ77로부터 클로닝된 glutathione S-transferase 유전자(phnC)의 염기서열을 결정하였다. 603bp의 open reading frame(ORF)이 존재하였고 개시코돈 앞에서 Shine-Dalgarno sequence를, 종결코돈 뒤에서는 terminator sequence를 발견하였다. phnC 유전자에서 만들어지는 phnC 단백질은 21,416 Da으로 SDS-polyacrylamide gel 전기영동 결과와 일치하였다. PhnC는 Bulkholderia cepacia LB400, Cycloclasticus oligotrophus RB1의 GST와 각각 53.7%, 49%의 높은 상동성을 나타냈다. 아미노산 서열의 상동성과 필수잔기들의 존재유무로 판단할 때 PhnC GST는 theta class GSTs와 진화적으로 유연관계가 높았지만 alpha, mu, pi, sigma class GSTs에서 구조적, 기능적으로 중요하다고 알려진 아미노산 잔기들이 PhnC GST에도 보존되어 있었다. 또한, phnC 유전자의 위치가 C. oligotrophus RB1, B. cepacia LB400 등의 GST 유전자 위치와 유사하다는 점에서 PhnC 효소는 난분해성 방향족 탄화수소의 분해에 관여하는 것으로 생각된다.

• Resources Recycling
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• v.7 no.5
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• pp.33-40
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• 1998

The formation reation of anhydrite (CaSO$_{4}$) depends upon the amount and velocity of the SO$_{3}$(g) and CaO(s) produced in the process of the thermal decomposition of alunite[K$_{2}SO_{4}{\cdot}Al_{2}(SO_{4})_{3}{\cdot}4Al(OH)_{3}$] and limestone (CaCO$_{3}$) respectively. Therefore, this study had carried out to investigate the amount and velocity of SO$_{3}$(g) produced by roasting alunite and pyrolytic materials. In air, alunite was transfouned into KAl(SO$_{4})_{2}$ and Al$_{2}O_{3}$ by dehydration at 500~580$^{\circ}C$. The dehydration velocity of alunite was found to be kt=(1-(1-${\alpha})^{1/3})^{2}$, the activation energy, 73.01 kcal/mol. SO$_{3}$(g) ware slowly produced by the thermal decomposition of KAl(SO$_{2})_{2}$, at 580~700$^{\circ}C$, rapidly, at 700~780$^{\circ}C$, The pyrolysis velocity of KAl(SO$_{4})_{2}$ was found to be kt=1-(1-${\alpha})^{1/1}$; activation energy, 66.84kcal/mol. The SiO$_{2}$ and kaolinite in alunite ore scarcely affected the temperature and velocity in which SO$_{3}$(g) were produced.

• Archives of Pharmacal Research
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• v.20 no.1
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• pp.53-57
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• 1997

For the purpose of defining the effects of the N-substituted alkyl groups on the anticonvulsant activities of N-Cbz-.alpha.-aminosuccinimides, various (R)- and (S)-N-alkyl substituted N-Cbz-.alpha.-aminosuccinimides (1 and 2) were prepared from the corresponding (R)- and (S)-N-Cbz-aspartic acid by using known reaction and were evaluated the anticonvulsant activies in the MES and PTZ tests, including their neurotoxicities. The most active compound in the MES test was (R)N-Cbz-.alpha.-amino-N-methylsuccinimide (1b) $(ED_{50}=52.5 mg/kg, Pl=3.2)$. And in case of the PTZ test, (R)-N-Cbz-.alpha.-amino-N-ethylsuccinimide (1c) was the most active compound $(ED_{50}/=32.5mg/kg, Pl=3.1)$. The order of anticonvulsant activities of these compounds against the MES test, as judged from the ED_50values for the R series (1), was N-methyl > N-isobutyl > non-substituted > N-ethyl, N-allyl > N-benzyl compound; for the S series (2) N-methyl > N-altyl > non-substituted > N-isobutyl > N-ethyl > N-benzyl compound. The anticonvulsant activities in the PTZ tests of these compounds exhibited somewhat different pattern ; for the R series (1) Nethyl > N-methyl > N-isobutyl> non-substituted > N-allyl > N-benzyl compound in order of decreasing activity; for S series (2) N-ethyl > N-allyl, non-substituted > N-isobutyl > N-methyl > N-benzyl compound in order of decreasing activity.