• Bulletin of the Korean Chemical Society
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• 제15권7호
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• pp.571-576
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• 1994

The photoreactions of $ReH_5(Cyttp)\;(1)\;(Cyttp=PhP(CH_2CH_2CH_2PCy_2)_2)\;with\;CO,\;CO_2\;and\;PMe_3 has been investigated to find the differences in reactivities from those of trismonophosphine analog. Irradiation of 1 under CO, $CO_2$ and excess $PMe_3$ in benzene results in the formation of the complexes, $ReH(CO)_2(Cyttp)\;(2),\;ReH_2({\eta}^2-HCO_2)(Cyttp)\;(3)\;and\;$ReH_3(PMe_3)(Cyttp)$ (4), respectively. The resulting products suggest that photoreactions of $ReH_5(Cyttp)$ proceed by photoextrusion of $H_2$ giving a phototransient species "$ReH_3$(Cyttp)" which can be trapped by CO, $CO_2\;and\;PMe_3$. The structures of 2, 3 and 4 are inferred based on $^1H,\;^{31}P$ NMR and I. R spectroscopy.

• 한국환경과학회지
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• 제20권8호
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• pp.1011-1019
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• 2011

The objective of this research is to evaluate optimal conditions of permeability and selectivity on the polysulfone membrane for efficiency of separation of $CH_4$ by checking four factors which are temperature, pressure, gas compositions and gas flow rates. When higher pressure was applied at the input, lower efficiency of recovery of $CH_4$ and higher efficiency of separation of $CH_4$ were shown. It has the tendency to show lower efficiency of recovery of $CH_4$ and higher efficiency of separation of $CH_4$ at the output as higher temperature at input. The lower flow rates make higher efficiency of recovery of $CH_4$ and lower efficiency of separation of $CH_4$. Finally, over 90% efficiency for $CH_4$ separation and recovery conditions are temperature ($-5^{\circ}C$), pressure (8 bar), gas composition rate (6:4) ($CH_4:CO_2$) and gas flow rate ($5\ell$/min). These conditions make higher separation and recovery efficiency such as 90.1% and 92.1%, respectively.

• 대한화학회지
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• 제38권8호
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• pp.570-575
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• 1994

$\alpha$-Methylpyridine유도체1(a∼f)는 n-BuLi과의 반응에서 $\alpha$-methylenylpyridinium 염 3(a∼f)을 형성한다. 3(a∼f)와 $Me_3SiCl$ 및 $Me_2SiClCH(SiMe_3)CH_2tBu$반응에서 생성물 4(a∼f) 와 5(a∼f)을 형성한다. 화합물 4(a∼f)에 있는 규소원자와 결합된 methylene기의 수소원자는 화합물 4(a∼f)의 $CH_3$기 보다 n-BuLi과의 반응성이 큰 것으로 확인되었다.

• BMB Reports
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• 제44권6호
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• pp.375-380
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• 2011

Bacillus licheniformis SK-1 naturally produces chitinase 72 (CHI72) with two truncation derivatives at the C-terminus, one with deletion of the chitin binding domain (ChBD), and the other with deletions of both fibronectin type III domain (FnIIID) and ChBD. We constructed deletions mutants of CHI72 with deletion of ChBD (CHI72${\Delta}$ChBD) and deletions of both FnIIID and ChBD (CHI72${\Delta}$FnIIID${\Delta}$ChBD), and studied their activity on soluble, amorphous and crystalline substrates. Interestingly, when equivalent amount of specific activity of each enzyme on soluble substrate was used, the product yield from CHI72-${\Delta}$ChBD and CHI72${\Delta}$FnIIID${\Delta}$ChBD on colloidal chitin was 2.5 and 1.6 fold higher than CHI72, respectively. In contrast, the product yield from CHI72${\Delta}$ChBD and CHI72${\Delta}$FnIIID-${\Delta}$ChBD on ${\beta}$-chitin reduced to 0.7 and 0.5 fold of CHI72, respectively. These results suggest that CHI72 can modulate its substrate specificities through truncations of the functional domains at the C-terminus, producing a mixture of enzymes with elevated efficiency of hydrolysis.

• 한국어병학회지
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• 제6권2호
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• pp.103-110
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• 1993

Sau3AI으로 부분절단한 Serratia marcescens genomic DNA(5Kb 이상)을 pUC19의 BamHI site에 삽입하여 total genomic library를 준비하였다. Swollen colloidal chitin media에서 halo를 형성하는 2개의 E.coli 형질전환주를 선별하였다. 이들 colony가 chitinase 유전자를 갖음을 재확인하기 위하여 4-methylumbelliferyl N-acetyl-$\beta$-D-glucosaminide(4-MuFGlcNAc)를 이용하였다. 4-MuFGlcNAc는 chitinase에 대한 기질특이성을 나타내며 형광을 나타내는 기질로서 positive clone들은 360nm의 자외선을 조사하였을 경우 밝은 형광을 나타낸다. pUC19으로 부터 유래된 2 종류의 다른 chitinase clone, pCH1(11.0Kb) 및 pCH2(7.5Kb)를 genomic DNA library로 부터 분리하였으며, 이들의 제한효소지도를 작성한 결과 서로 다른 제한효소지도를 나타내었다. pCH1EA 및 pCH2로 부터 각각의 EcoRI-Xbal fragment를 subcloning함으로써 두개의 다른 chitinase 유전자의 위치를 결정하였다. pCH1EA 및 pCH2를 cross hybridization 한 결과 hybridization signal을 나타내지 않아 서로 유사성이 없는 것으로 사료된다.

• 대한화학회지
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• 제39권5호
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• pp.393-398
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• 1995

이소부틸과 부틸아미드옥심으로 한 배위자, ${Mo(NO)_2}^{2+}$ 단위체를 포함한 단핵체 및 다핵산소 금속체의 반응에서 $(n-Bu_4N)_2[M_4O_{12}Mo(NO)_2{RC(NH_2)NHO}_2{RC(NH)NO}_2]\; (M=Mo,\; W; R=(CH_3)_2CH, n-CH_3CH_2CH_2)$을 합성하였다. 얻은 착물은 원소분석, 적외선, 핵자기공명 및 전자흡수 스펙트럼에 의해 특성을 조사하였다. 얻은 물질의 골격구조는 금속의 산화상태 6가로 구성된 2개의 이핵체 ${M_2O_5}^{2+} [M=Mo, W]와 몰리브덴의 산화상태 0가인 ${Mo(NO)_2}^{2+}$로 형성되어 있다. ${Mo(NO)_2}^{2+}$ 단위체는 형식상 시스 형태이며 기하학적으로 $C_{2V}$ 대칭을 가진다. 몰리브덴과 텅스텐의 산화상태 6가와 ${Mo(NO)_2}^{2+}$ 단위체는 전자적 편재화로 상호작용이 거의 없었다. 이러한 결과를 분광학적으로 확인하였다.

• 대한한방내과학회지
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• 제37권4호
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• pp.591-600
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• 2016

Objective: This study aimed to examine the relaxation effects and underlying mechanisms of Cynomorii herba (CH) extract in isolated rabbit corpus cavernous tissues.Methods: We experimented with CH extract (0.01-3.0 mg/mL). Nω-nitro-L-arginine (L-NNA) was experimented before the CH extract to contracted strips induced by phenylephrine (PE, 1 μM)and compared with nonexperimented. In addition, we experimented with calcium chloride (Ca²⁺, 1 mM) after pretreatment of the CH extract in Ca²⁺-free Krebs-Ringer solution to contracted strips induced by PE. The cell viability and nitric oxide (NO) concentration of human umbilical vein endothelial cells (HUVECs) were measured by an methylthiazol-2-yl-2, 5-diphenyl tetrazoliumbromide (MTT) assay and Griess reagent system. The ratio of smooth muscles to collagen fibers, in addition to eNOS- and PDE-5-positive reactions, was examined by histochemical and immunohistochemical staining.Results: The CH extract significantly induced the relaxation of the cavernous strips, and the pretreatment with L-NNA inhibited CH extract-induced relaxation. The L-NNA pretreatment reduced the increased contraction induced by the addition of Ca²⁺in Ca²⁺-free solution. Furthermore, the NO concentration of the HUVECs increased. When the CH extract was applied to the corpus cavernosum of the penis (CCP) of Sprague Dawley rats, the ratio of smooth muscles to collagen fibers by PE and the formation of eNOS around the helicine artery increased. However, the CH extract treatment decreased PDE-5 positive reactions.Conclusions: These results show that the relaxation effects induced by the CH extract are associated with the suppression of the influx of extracellular Ca²⁺ via the production of NO and eNOS and inhibition of PDE-5.

• 약학회지
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• 제18권3호
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• pp.183-189
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• 1974

Distribution coefficients between nitrobanzene solution and deionized water, show a straight line when the number of alkyl radicals against the logarithm of distribution coefficient of the salts was plotted. After extracting salts of the indicator and the cationic surfactants with organic solvents, and employing the colorimetric method was used. A calculation method of distribution coefficients of the salts in the organic solvent has been suggested and it could be used for the extraction equilibrium of the primary amine, $CH_{3}(CH_2)_{n}NH_3^+$ secondary amine, $CH_{3}(CH_2)_{n}NH_{2}(CH_3)^+$, tertiary amine $CH_{3}(CH_2)_{n}NH(CH_3)_2^+$ and quaternary ammonium, $CH_{3}(CH_2)_{n}N(CH_3)_3^+$MO$^-$salts, (n=3,5,7,11).

• Restorative Dentistry and Endodontics
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• 제40권1호
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• pp.44-49
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• 2015

Objectives: This study compared the ability of several techniques to remove calcium hydroxide (CH) from the root canal and determined the influence of CH residues on the accuracy of the electronic apex locator. Materials and Methods: Root canals of 90 human maxillary lateral incisors with confirmed true working length (TWL) were prepared and filled with CH. The teeth were randomly assigned to one of the experimental groups according to the CH removal technique (n = 14): 0.9% saline; 0.9% saline + master apical file (MAF); 17% ethylenediamine tetraacetic acid (EDTA); 17% EDTA + MAF; 5.25% sodium hypochlorite (NaOCl); 5.25% NaOCl + MAF. Six teeth were used as negative control. After CH removal, the electronic working length was measured using Root-ZX (Morita Corp.) and compared with TWL to evaluate Root-ZX accuracy. All specimens were sectioned longitudinally, and the area of remaining CH (CH) and total canal area were measured using imaging software. Results: The EDTA + MAF and NaOCl + MAF groups showed better CH removal than other groups (p < 0.05). Root-ZX reliability to prevent overestimated working length to be > 85% within a tolerance of ${\pm}1.0mm$ (p < 0.05). There was strong negative correlation between amount of CH residues and EAL accuracy (r = -0.800 for ${\pm}0.5mm$; r = -0.940 for ${\pm}1.0mm$). Conclusions: The mechanical instrumentation improves the CH removal of irrigation solutions although none of the techniques removed the dressing completely. Residues of CH medication in root canals affected the accuracy of Root-ZX adversely.

• 대한화학회지
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• 제36권4호
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• pp.565-578
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• 1992

수용액 및 유기용매-물 혼합용매속에서 L이 $NH_3$, $NH_2$$CH_3$, $glyOC_2H_5$, $glyOCH_3$, $dl-alaOC_2$$H_5$, $NH_2$$CH_2$$CONH_2$, $NH_2$CH$_2$CN 이 배위된 cis-[Co(en)$_2$(L)Cl]$^{2+}$ (en = 1,2-diaminoethane)에 $Hg^{2+}$을 작용시켰을 때 속도론적인 자료, 원평광이색성 스펙트라, 이온교환 크로마토그래피에 의한 생성물 분석 및 용매의 성질인 Y(ionizing power)를 이용한 m(Grunwald-Winstein의 기울기)값의 결과들로 부터 반응은 I$_{d-}$메카니즘으로 제안되었다. 반응 결과 L이 $NH_3$과 NH$_2$CH$_3$이 배위된 cis-[Co(en)$_2$(L)Cl]$^{2+}$은 Cl$^-$이 해리되어 H$_2$O 분자가 치환되었으며, L이 glyOC$_2$H$_5$, glyOCH$_3$, dl-alaOC$_2$H$_5$, NH$_2$CH$_2$CONH$_2$과 NH$_2$CH$_2$CN이 배위된 cis-[Co(en)$_2$(L)Cl]$^{2+}$은 Co(Ⅲ)에 대한 각 리간드 L의 킬레이트화가 일어났다. 에탄올-물 혼합용매 속에서 cis-[Co(en)$_2$(NH$_2$CH$_2$CN)Cl]$^{2+}$을 제외한 cis-[Co(en)$_2$(L)Cl]$^{2+}$은 에탄올의 양이 증가될수록 속도상수(k)의 값이 증가되었고, 또한 30${\%}$ 유기용매-물 혼합용매 속에서의 속도상수의 값은 30${\%}$ 2-프로판올-물>30${\%}$ 에탄올-물>물의 순서를 나타내었다. 그러나 cis-[Co(en)$_2$(NH$_2$CH$_2$CN)Cl]$^{2+}$은 이와 반대의 결과를 나타내었다. 각 착물들의 속도상수의 차이에 있어서 cis-[Co(en)$_2$(NH$_3$)Cl]$^{2+}$ 및 cis-[Co(en)$_2$(NH$_2$CH$_3$)Cl]$^{2+}$은 리간드장 파라메타(${\Delta}$)와 관계가 있었지만, cis-[Co(en)$_2$(L)Cl]$^{2+}$(L = $glyOC_2$H$_5$, glyOCH$_3$, dl-alaOC$_2$H$_5$, $NH_2$CH$_2$CONH$_2$, $NH_2$CH$_2$CN)은 이와 관계가 없었다. cis-[Co(en)$_2$(L)Cl]$^{2+}$에 대하여 $NO_3^-$을 첨가시켜 $Hg^{2+}$이 촉매로서 작용하는 반응에서 $NO_3^-$에 의하여 그 반응 메카니즘이 변화되는 것이 아니라 단지 속도만 변화되었다.