• 대한화학회지
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• 제14권2호
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• pp.161-168
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• 1970

In order to obtain the more effective evidence, supporting the hypothesis which have been previously described by former report that pepsin (EC 3.4. 4.1) forms a hydrophobic bond with the nonpolar side chain of its substrate, the inhibitory effect of carboxylic acids(from formic acid to iso-butyric acid) on the activity of pepsin to the synthetic dipeptide, N-Carbobenzoxy-L-glutamyl-L-tyrosine, was discussed. The kinetic study showed that the inhibition by carboxylic acids was competitive. The Kidecreased with increasing size of the inhibitor molecule. The $-{\Delta}F^{\circ}$increased linearly with increasing number of carbon atoms in the hydrocarbon chain of the inhibitor. It was confirmed that the hydrophobic bond between more than one side chain of amino acid residues(phenylalanine) in the binding region of the active center of pepsin and the side chain of amino acid residues in the substrate was formed as the first step of its enzymic mechanism. The inhibitory effect of carboxylic acids was due to the competition of the hydrocarbon group of the carboxylic acids with the side chain of the substrate for the hydrophobic binding site(the side chain of phenylalanine) of the pepsin.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 D
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• pp.1815-1817
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• 1999

In this paper, the generation of high pretilt angle in nematic liquid crystal (NLC) by dipping effect on three kinds of the rubbed polyimide (PI) surface was investigated. The generated pretilt angle of NLC increases due to dipping effect before rubbing treatment on two kinds of the rubbed PI surface with side chain. The generated pretit angle in NLC by using dipping effect after rubbing treatment on PI surface with short side chain is high compared to the PI surface with long side chain. The generated pretit angle of the positive type NLC $(\Delta{\varepsilon}>0)$ is higher as than that of the negative type NLC $({\Delta}{\varepsilon}<0)$ by using dipping effect before rubbing treatment on homeotropic layer. The generated pretilt angle of NLC is attributed to perpendicular component of permittivity ${\varepsilon}_{\perp}$ of NLC on rubbed PI surface.

• Bulletin of the Korean Chemical Society
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• 제18권5호
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• pp.528-534
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• 1997

The conformation and stabilization effects of acridine derivatives 9-aminoacridine, an acridine with an aminoalkyl side chain, bis acridine (two acridines linked by an aminoalkyl side chain), and proflavin in the triplex helical poly(dA)·[poly(dT)]2 were investigated by optical spectroscopies. Based on the negative LD and weak positive CD in the acridine absorption wavelength region, we concluded that the acridine moiety of all derivatives are intercalated. We also examined the melting temperatures. Of all the compounds examined, the acridine with an amino alkyl side chain had the strongest effect on the stabilization of the third strand of a poly (dA)·[poly(dT)]2 triplex. The role of the side chain, based on this observation, is discussed.

• 공업화학
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• 제10권5호
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• pp.743-747
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• 1999

비상용성인 polystyrene(PS)와 polymethacrylate(PMA)의 블렌드에서 분자간 수소결합이 가능하도록 구성고분자를 변성하였다. 공중합을 통해 hydroxystyrene 함량이 몰분율로 각각 7%, 10%, 18% 도입된 poly(styrene-co-4-hydroxystyrene) (modified polystyrene, MPS)을 합성하여 블렌드의 상용성 변화를 살펴보았다. 또한 PMA의 측쇄의 크기가 분자간 수소결합 형성에 미치는 영향을 조사하기 위하여 각각 methyl기, butyl기, hexyl기, ethylhexyl기의 측쇄를 갖는 PMA를 선정하였다. 그 결과 수산기의 함량이 증가함에 따라 분자간 수소결합 형성이 증가하였다. PMA의 측쇄의 크기에 따라 수소결합 형성 정도가 영향을 받아 상용성에 큰 차이가 나타남을 온도변화에 따른 상변화 거동을 통하여 확인하였다. 측쇄의 크기가 증가됨에 따라 입체장애 효과와 증가된 사슬의 운동성 때문에 분자간 수소결합의 형성 및 수소 결합력은 크게 감소하였다.

• Elastomers and Composites
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• 제40권1호
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• pp.3-11
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• 2005

시차열분석계(DSC)를 이용하여 달린(pendant) 탄소카본길이가 8(C-8), 12(C-12), 16(C-16)인 3 가지 종류의 무수화물(ASA)과 두 가지 촉매를 이용한 에폭시 수지의 경화 동력학을 연구하였다. 비등온(Nonisothermal)과 등전환(Isoconversional)법을 사용하였다. 비등온법의 결과는 무수화물의 달린 카본길이에 따른 결과에는 큰 차이가 없었다. 그러나 등전환법에서는 촉매사용에 따라 개시반응의 활성화 에너지가 C-8, C-12, 그리고 C-16의 경우 각각 $61.7{\sim}57.7kJ/mol$, $63.0{\sim}57.3 kJ/mol$, 그리고 $130.4{\sim}94.2 kJ/mol$이었다. 보고된 개시반응의 활성화에너지 20 kJ/mol 과 다른 것은 무수화물의 달린 탄소길이에 따른 효과로 해석된다.

• 공업화학
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• 제25권5호
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• pp.487-496
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• 2014

본 연구에서는 phenothiazine과 benzothiadiazole을 기반으로 하고, phenothiazine의 질소 위치에 다양한 side-chain을 치환한 고분자를 합성하였다. 합성된 고분자는 광학적, 전기화학적 분석 결과 300~700 nm에서 흡수를 보였고, -5.4 eV 정도의 이상적인 HOMO energy level를 갖는 특성을 확인하였다. 고분자와 $PC_{71}BM$을 광활성층으로 사용한 소자를 제작하였고, 측정결과 branched side-chain을 가지며 탄소수가 많은 P2HDPZ-bTP-OBT가 2.4%로 최대 광전변환효율을 갖는 것으로 확인되었다($V_{OC}$ : 0.74 V, $J_{SC}$ : $6.9mA/cm^2$, FF : 48.0%).

• PNF and Movement
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• 제9권1호
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• pp.1-9
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• 2011

Purpose : The purpose of this study is to analyze the effect of closed-chain exercise on weight supporting rate change within hemiplegic side and static dynamic balance ability in stroke patients. Methods : The subjects of the study were 13 hemiplegic patients who carried out closed-kinematic chain exercise program over 6 weeks. The exercises of the program are stand to sit with stall bar, stair-up & down by a hemiplegic leg and bridging exercise crossing the non-hemiplegic leg onto the hemiplegic leg. Each exercise was carried out over 3 sets of 10reps. Results : The results of this study were summarized as follows: 1. After intervention, there was a statistically significant change in the weight supporting rate within hemiplegic and non-hemiplegic side(P<0.05). 2. After intervention, there was a statistically significant change in the static balance(FICSIT-4) ability(P<0.05). 3. After intervention, there was a statistically significant change in the dynamic balance(FSST, TUG, FRT) ability(P<0.05). Conclusion : The results of the study suggests that closed-chain exercise program in stroke patients improves their weight supporting rate and enhance the static dynamic balance.

• 한국광학회지
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• 제9권4호
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• pp.215-220
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• 1998

전기광학 폴리머(electro-optic polymer)의 다양한 전기광학 특성을 동시에 측정하기 위한 실험장치와 기법을 제안하였다. 제안된 실험장치를 이용하여 폴링(poling)전 측쇄(side-chain)결합형 전기광학 폴리머 필름에 강한 de 및 ac 전기장을 인가시 발생하는 전기광학 효과와 복굴절을 관측하였다. 다양한 폴링조건에 따른 전기광학 계수의 의존성을 실시간으로 측정하였다. 폴링후의 폴리머 필름의 열적 안정성을 평가하기 위하여 전기광학 효과의 이완현상을 측정하여 잘 알려진 전기광학 폴리머와 특성을 비교하였다. 이 실험장치는 실험과정과 시간을 줄일 수 있다.

• 대한의생명과학회지
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• 제7권3호
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• pp.127-131
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• 2001

This study was undertaken to examine the effect of amino acids on anoxia-induced cell injury in rabbit renal cortical slices. In order to induce anoxic cell injury, slices were exposed to a 100% $N_2$ atmosphere and control slices were exposed to 100% $O^2$. Irreversible cell injury was estimated by measuring lactate dehydrogenase (LDH) release and alterations in renal cell function were examined by measuring p-aminohippurate (PAH) uptake. Anoxia caused the increase in LDH release in a time-dependent manner. Glycine and glutathione almost completely prevented anoxia-induced LDH release. Of amino acids tested, glycine and alanine exerted the protective effect against anoxia-induced cell injury. However, asparagine with amide side chain, leucine and valine with hydrocarbon side chain, and basic amino acids (lysine, histidine, and arginine) were not effective. Anoxia-induced inhibition of PAM uptake was prevented by glycine. ATP content was decreased by anoxia, which was not affected by glycine. Anoxia-induced depletion of glutathione was significantly prevented by glycine. These results suggest that neutral amino acids with simple structure exert the Protective effect against anoxia-induced cell injury the involvement of specific interaction of amino acids and cell structure.

• Bulletin of the Korean Chemical Society
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• 제20권9호
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• pp.1010-1016
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• 1999

We synthesized the photoresponsive side chain polymers containing aminonitro azobenzene for studying the effect of temperature on photoinduced birefringence. Four different copolymers were prepared using methacrylate, α-methylstyrene, and itaconate monomer. Photoisomerization was observed under the exposure of UV light using UV-VIS absorption spectroscopy. Reorientation of polar azobenzene molecules induced optical anisotropy under a linearly polarized light at 532 nm. The change of the birefringence was observed with increasing the sample temperature under a continuous irradiation of excitation light. We could estimate the activation energy of molecular motion in thermal and photochemical mode. Besides the effect of glass transition temperature on the activation energy, we focused our interests on the effect of geometrical hindrance of polar azobenzene molecules and cooperative motion of environmental mesogenic molecules in the vicinity of polar azobenzene molecules.