• Title/Summary/Keyword: ethanol activation

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Application of the Extended Grunwald-Winstein Equation to the Solvolyses of Phenyl Methanesulfonyl Chloride in Aqueous Binary Mixtures

  • Koh, Han-Joong;Kang, Suk-Jin
    • Bulletin of the Korean Chemical Society
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    • v.32 no.6
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    • pp.1897-1901
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    • 2011
  • This report shows the rates of solvolyses for phenyl methanesulfonyl chloride ($C_6H_5CH_2SO_2Cl$, I) in ethanol, methanol, and aqueous binary mixtures incorporating ethanol, methanol, acetone, 2,2,2-trifluroethanol (TFE) and 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) are reported. Three representative solvents, studies were made at several temperatures and activation parameters were determined. The thirty kinds of solvents gave a reasonably precise extended Grunwald-Winstein plot, coefficient (R) of 0.954. The sensitivity values (l = 0.61 and m = 0.34, l/m = 1.8) of phenyl methanesulfonyl chloride (I) were smaller than those obtained for benzenesulfonyl chloride ($C_6H_5SO_2Cl$, II; l = 1.01 and m = 0.61) and 2-propanesulfonyl chloride ($(CH_3)_2CHSO_2Cl$, III; l = 1.28 and m = 0.64). As with the two previously studied solvolyses, an $S_N2$ pathway with somewhat ionization reaction is proposed for the solvolyses of I. The activation parameters, ${\Delta}H^{\neq}$ and ${\Delta}S^{\neq}$, were determined and they are also in line with values expected for a bimolecular reaction mechanism. The kinetic solvent isotope effect of 2.34 in $CH_3OH/CH_3OD$ is in accord with a bimolecular mechanism, probably assisted by general-base catalysis.

Kinetic Studies of Chlorine Exchange between Benzyl Chloride and Radioactive Chloride Ion (Benzyl Chloride의 Chlorine 交換反應)

  • Park, Yong-Ja;Lee, Ik-Choon
    • Journal of the Korean Chemical Society
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    • v.9 no.1
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    • pp.23-28
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    • 1965
  • Halogen exchanges between benzyl chloride and chloride ion have been studied in 90% ethanol-water mixture, and activation parameters in the exchange reaction have been determined; ${\Delta}H^{\neq}$ = 18. 50 Kcal and ${\Delta}S^{\neq}$ = -22. 09 e. u. Results indicated that the reaction proceeded via a typical bimolecular mechanism. The importance of nucleophilic ability of attacking anion in $S_N2$ process has been stressed giving some experimental evidence. The order of reactivity of halides in the exchange reaction is better explained with the Swain's nucleophilic parameter than with the bond dissociation energies.

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A Kinetic Study on Solvolysis of Diphenyl Thiophosphorochloridate

  • Koh, Han-Joong;Kang, Suk-Jin;Kevill, Dennis N.
    • Bulletin of the Korean Chemical Society
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    • v.30 no.2
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    • pp.383-388
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    • 2009
  • Rates of solvolyses of diphenyl thiophosphorochloridate ($(PhO)_2$PSCl, 1) in ethanol, methanol, and aqueous binary mixtures incorporating ethanol, methanol, acetone and 2,2,2-trifluoroethanol (TFE) are reported. For four representative solvents, studies were made at several temperatures and activation parameters were determined. The 30 solvents gave a reasonably precise extended Grunwald-Winstein plot, correlation coefficient (R) of 0.989. The sensitivity values (l = 1.29 and m = 0.64) of diphenyl thiophosphorochloridate ($(PhO)_2$PSCl, 1) were similar to those obtained for diphenyl phosphorochloridate ($(PhO)_2$POCl, 2), diphenylphosphinyl chloride ($Ph_2$POCl, 3) and diphenylthiophosphinyl chloride ($Ph_2$PSCl, 4). As with the previously studied of 3~4 solvolyses, an $S_N$ pathway is proposed for the solvolyses of diphenyl thiophosphorochloridate (1). The activation parameters, ${\Delta}H^{\neq}\;(=11.6{\sim}13.9\;kcal{\cdot}mol^{-1})\;and\;{\Delta}S^{\neq}\; (=\;-32.1\;{\sim}\;-42.7\;cal{\cdot}mol^{-1}{\cdot}K^{-1})$, were determined, and they were in line with values expected for an $S_N$2 reaction. The large kinetic solvent isotope effects (KSIE, 2.44 in MeOH/MeOD and 3.46 in $H_2O/D_2$O) are also well explained by the proposed $S_N$2 mechanism.

Inhibitory effects of Oxya chinensis sinuosa ethanol extract on RANKL-induced osteoclast differentiation

  • Ra-Yeong Choi;Bong Sun Kim;Sohyun Park;Minchul Seo;Joon Ha Lee;HaeYong Kweon;In-Woo Kim
    • International Journal of Industrial Entomology and Biomaterials
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    • v.48 no.1
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    • pp.13-18
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    • 2024
  • The rice field grasshopper, Oxya chinensis sinuosa (OC), has traditionally been utilized in Korea for various purposes; however, its potential benefits in the context of osteoporosis remain unclear. The results revealed that OC ethanol extract (OCE) significantly inhibited the formation and activity of tartrate-resistant acid phosphatase (TRAP)-positive cells in receptor activator of nuclear factor-κB ligand (RANKL)-stimulated RAW264.7 cells. Furthermore, OCE, at concentrations ranging from 100 to 400 ㎍/mL, demonstrated a dose-dependent reduction in the protein expression of osteoclast-specific markers, including nuclear factor of activated T cell cytoplasmic 1, c-Src, and TRAP, when compared to RANKL stimulation alone. Additionally, OCE significantly inhibited RANKL-induced activation of p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase (JNK) but not the activation of extracellular signal-regulated kinase. Collectively, these results indicate that OCE suppresses osteoclastogenesis by attenuating the phosphorylation of p38 MAPK and JNK. Consequently, these findings suggest that OCE holds promise for the prevention of osteoporosis.

Screening of Immune Activation Activities in the Leaves of Dendropanax morbifera Lev. (황칠나무 잎의 면역활성증진기능 탐색)

  • Lee, Seo-Ho;Lee, Hyun-Soo;Park, Young-Sik;Hwang, Baik;Kim, Jae-Hun;Lee, Hyeon-Yong
    • Korean Journal of Medicinal Crop Science
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    • v.10 no.2
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    • pp.109-115
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    • 2002
  • The immune activation activities of ethanol, ethanol : water(1 : 1,v/v) and water extracts from Dendropanax morbifera Lev. were compared. The crude extracts showed relatively low cytotoxicity as less than 26% by using human normal liver cell(WRL-68). For example, the ethanol extract inhibited. in MCF7 and Hep3B cells in adding 1.0 mg/mL ethanol extracts. The growth of human immune T and B cells was enhanced up to $1.22{\sim}1.27$ times by adding the crude extracts. These are a trend of increasing secretion of $cytokines(IL-6,\;TNF-{\alpha})$ from human B/T cell for 6 day cultivation. It was found that the immune activation activities of the crude extracts seemed to be higher than those obtained by using other solvents.

Suppression of Microglial Activation by Acute Ethanol Administration through HT7 Stimulation (급성 알코올 투여 백서의 신문혈 자극이 소교세포 활성에 미치는 영향)

  • Su Yeon Seo;Se Kyun Bang;Suk Yun Kang;Seong Jin Cho;Kwang-Ho Choi;Yeonhee Ryu
    • Korean Journal of Acupuncture
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    • v.41 no.2
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    • pp.33-42
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    • 2024
  • Objectives : The sigma-1 receptor is implicated in stress, depression, psychostimulant sensitization, and addiction vulnerability. Prior studies have indicated that ethanol exposure modulates sigma-1 receptor activity within the Ventral Tegmental Area (VTA). Here, we explore the sub-mechanisms underlying sigma-1 receptor activity induced by HT7 (Shinmun) stimulation in behavioral alterations following acute ethanol (ETOH) administration. Methods : Male Wistar rats were investigated for pro- and anti-inflammatory markers after injection of ETOH (1 g/kg) using cytokine enzyme-linked immunosorbent assay (ELISA)s. After confirming that HT7 stimulation changed the total distance traveled in the open field test (OFT), protein changes in the Ventral tegmental area (VTA) were measured by Western blotting. The expression level of inducible nitric oxide synthase (iNOS) after administration of a sigma-1 receptor antagonist (dihydrobromide 1047; BD1047, 10 mg/kg i.p.) and Shenmen (HT7) stimulation was compared. Results : As a result, acute ETOH administration increased proinflammatory marker levels (TNF-𝛼 and IL-6). HT7 stimulation restored the total distance response after acute ethanol administration. In addition, in the VTA, the levels of a microglial marker (iNOS), sigma-1 receptor and protein kinase C, which are predicted to be involved in up- and downregulation, were restored by HT7 stimulation. In particular, HT7 stimulation modulates iNOS expression through effects similar to BD treatment. This study suggests that the stimulatory effect of HT7 may be driven by microglial activation. Conclusions : Microglial activity is regulated by sigma-1 receptor, and sigma-1 receptor activity is regulated by HT7 stimulation. Significantly, we demonstrate that HT7 stimulation ameliorates behavioral alterations induced by acute ETOH administration through microglial activation within the VTA.

Identification of Phosphatidylcholine-Phospholipase D and Activation Mechanisms in Rabbit Kidney Proximal Tubule Cells

  • Chung, Jin-Ho;Chae, Joo-Byung;Chung, Sung-Hyun
    • BMB Reports
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    • v.29 no.1
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    • pp.11-16
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    • 1996
  • The present study showed that receptor-mediated activation of rabbit kidney proximal tubule cells by angiotensin II, the $Ca^{2+}$ ionophore A23187, or the protein kinase C activator phorbol myristate acetate (PMA) all stimulated phospholipase D (PLD). This was demonstrated by the increased formation of phosphatidic acid, and in the presence of 0.5% ethanol, phosphatidylethanol (PEt) accumulation. Angiotensin II leads to a rapid increase in phosphatidic acid and diacylglycerol, and phosphatidic acid formation preceeded the formation of diacylglycerol. This result suggests that some phosphatidic acid seems to be formed directly from phosphatidylcholine hydrolyzed by Pill. On the other hand, EGTA substantially attenuated angiotensin II and A23187-induced PEt formation, and when the cells were pretreated with verapamil angiotensin II-induced Pill activation was completely abolished. These results provide the evidence that calcium ion influx is essential for the agonist-induced Pill activation. In addition, staurosporine, an inhibitor of protein kinase C, strongly inhibited PMA-induced PEt formation, but was ineffective on angiotensin II-induced PEt accumulation. $GTP{\gamma}S$ also stimulates PEt formation in digitonin-permeabilized cells, but pretreatment of the cells with pertussis toxin failed to suppress angiotensin II-induced PEt formation. From these results, we conclude that in the rabbit kidney proximal tubule cells the mechanisms of angiotensin II- and PMA-induced Pill activation are different from each other and mediated via a pertussis toxin-insensitive trimeric G protein.

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Effects of Culture Conditions on The Expression of Cyclin B1 Protein during the First Meiotic Maturation in Bovine Immature Oocytes

  • Hwang Seong-Soo;Yoon Jong-Taek
    • Reproductive and Developmental Biology
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    • v.30 no.2
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    • pp.115-118
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    • 2006
  • Cyclin B1 is known to reflect the M-phase promoting factor (MPF), a universal regulator of G2/M-phase transition, activity during the process of oocytes maturation. To investigate whether culture condition affects the maturation rate and the expression of cyclin B1 protein, bovine immature oocytes are stimulated and cultured according to the following protocols: Experiment 1: denuded oocytes (denude) only, COC only, denuded oocytes+granulosa cells (denude+GCs) and COC+GCs; Experiment 2: no-activation (control), 7% ethanol for 5 min and $10{\mu}l/ml$ ionomycin for 5 min at immediately before maturation. The maturation rates of denude and no-activation group were significantly lower in both experiments (P<0.05), respectively. Co-culture or stimulation method in bovine immature oocytes culture increases the cyclin B1 expression significantly in both experiments (P<0.05). Based on these results, culture condition affects the maturation rate and the expression of cyclin B1 protein during the first meiotic maturation in bovine immature oocytes.

The Relationship between Affinity of Membrane and Optimum Operation Conditions in the Pervaporation of Aqueous Ethanol (에탄올 수용액의 투과증발에 있어서 막의 친화성과 최적 조업조건의 관계)

  • 전종기;명완재;임선기
    • Membrane Journal
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    • v.1 no.1
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    • pp.34-43
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    • 1991
  • The relationships between affinity of membranes and optimum operation conditions were investigated in the pervaporation of water(1)/ethanol(2) mixture through cellulose acetate(CA) membranes having more affinity to water and silicone rubber(SR) membranes having more affinity to ethanol. CA and SR membranes were prepared and amount of sorption, sorption selectivity, pervaporation separation factor and pervaporation rate in both of membranes were determined and compared. The effects of downstream pressure were analyzed using Thompson diagram and the sorption and pervaporation characteristics with composition of feed and operation temperature were examined in terms of affinity, activity coefficient, plasticizing effect and activation energy of individual species. In the separation of water through CA membranes, high performance of both pervaporation separation factor (water to ethanol, $[\alpha^2_1]_{PV}$) and pervaporation rate was obtained in the conditions of low downstream pressure, middle range of feed concentration and high temperature. In the separation of ethanol through SR membranes, pervaporation separation factor(ethanol to water, $[\alpha^2_1]_{PV}$) increased with downstream pressure and decreased with concentration of ethanol in feed and operation temperature, while pervaporation rate showed opposite trends to those of ($[\alpha^2_1]_{PV}$).

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Effects of Ethanol Extract of Benincasa Seeds on the Experimental Cellular Model of Nonalcoholic Fatty Liver Disease (동과자 에탄올 추출물이 비알코올성 지방간 세포 모델에 미치는 효과)

  • Choi, Jun-Young;Kim, So-Yeon;Kwun, Min-Jung;Kim, Kyun-Ha;Joo, Myung-Soo;Han, Chang-Woo
    • The Journal of Internal Korean Medicine
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    • v.33 no.4
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    • pp.438-447
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    • 2012
  • Objectives : In this study, we investigated the effect and the underlying mechanism of ethanol extract of Benincasa seeds on a cellular model of non-alcoholic fatty liver disease (NAFLD) established by treating HepG2 cells with palmitate. Methods : We evaluated ethanol extract of Benincasa seeds (EEBS) for its hepatic lipid-lowering potential in fatty acid overloaded HepG2 cells. After incubation in palmitate containing media with or without EEBS, intracellular neutral lipid accumulations were quantified by Nile red staining. We also investigated the effect of EEBS on lipogenesis and ${\beta}$-oxidation. $LXR{\alpha}$-dependent SREBP-1c activation, expression of lipogenic genes, and expression of ${\beta}$-oxidation related genes were determined with or without pretreatment of EEBS. Results : EEBS significantly attenuated palmitate-induced intracellular neutral lipid accumulation in HepG2 cells. EEBS suppressed fatty acid synthesis by inhibiting $LXR{\alpha}$-dependent SREBP-1c activation. EEBS also repressed SREBP-1c mediated induction of lipogenic genes, including ACC, FAS, and SCD-1. However, EEBS had no effect on ${\beta}$-oxidation related CPT-1 and $PPAR{\alpha}$ gene expression. Conclusions : Our results suggest that EEBS has an efficacy to decrease hepatic lipid accumulation, and this effect was mediated by inhibiting the $LXR{\alpha}$-SREBP-1c pathway that leads to expression of lipogenic genes and hepatic steatosis. Therefore, the Benincasa seeds may have a potential clinical application for treatment of this chronic liver disease.