• 한국안광학회지
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• 제17권1호
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• pp.91-97
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• 2012

목적: 본 연구는 노인성 황반변성(age-related macular degeneration, AMD)의 병인으로 잘 알려진 A2E의 광산화가 자외선 차단렌즈나 brown 착색렌즈에 의해 억제되는가를 알아보고자 하였다. 방법: 두 분자의 all-trans-retinal과 한 분자의 ethanolamine을 합성하여 만든 A2E에 청색광(420~470 nm, $94mW/cm^2$)을 3분 동안 조사하여 광산화를 유도하였다. UV 차단 및 brown 착색 안경렌즈의 A2E의 광산화 저해 효과는 광산화되지 않고 남아있는 A2E의 흡광도와 HPLC chromatogram 분석을 통하여 확인하였다. 결과: 자외선 차단렌즈는 청색광 조사로 유발되는 A2E의 광산화를 억제하지 못하였다. 반면 Brown 착색렌즈에서는 가시광선 차단율이 15%인 경우 A2E의 광산화율에는 별차이가 없었지만, 55%와 86% 차단된 렌즈에서는 각각 9.98%, 16.55%의 A2E 광산화 억제 효과를 보였다. HPLC로 분석한 잔존 A2E량을 확인해 보면 렌즈로 차단하지 않은 A2E의 잔존량은 $199.29{\pm}26.53{\mu}M$ 이었으나, 55% 차단율을 가진 brown 렌즈는 $264.58{\pm}31.91{\mu}M$, 86% 차단율을 가진 렌즈에서는 $402.93{\pm}26.68{\mu}M$의 A2E 잔존량을 보여 A2E 광산화 억제효과가 있음을 확인하였다. 반면, 자외선 차단렌즈의 경우에는 잔존량 분석에서도 광산화 억제효과가 없는 것으로 나타났다. 결론: 본 연구결과를 통하여 brown 착색 안경렌즈는 노인성 황반변성의 원인물질인 A2E의 광산화를 억제하는 효과가 있는 것으로 알 수 있었다.

• 한국통신학회:학술대회논문집
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• 한국통신학회 1987년도 추계학술발표회 논문집
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• pp.35-38
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• 1987

• 한국농공학회논문집
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• 제56권3호
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• pp.11-17
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• 2014

We investigated the applicability of steel slag as a capping material in order to minimize phosphorus(P) release into seawater. Steel slag is a byproduct from the iron and steel industries and the use of steel slag has some advantages in respect of both cost and environmental concern. P removal by steel slag were studied in a batch system with respect to changes in contact time and initial concentration. Kinetic adsorption data were described well by pseudo 2nd order model, indicating rate limiting step for P adsorption to steel slag is chemical sorption. Equilibrium adsorption data fitted well to Langmuir isotherm model which describes for single layer adsorption. The maximum P adsorption capacity of steel slag was 7.134 mg-P/L. Increasing the depth of steel slag produced a positive effect on interruption of P release. More than 3 cm of steel slag was effective for blocking P release and 5 cm of steel slag was recommended as the depth for capping of P contaminated marine sediments. Increasing P concentration and flow rate had a negative effect on P removal ratio. It was concluded that the steel slag has a potential capping material for blocking P release from marine sediments.

• Biomolecules & Therapeutics
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• 제3권3호
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• pp.192-198
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• 1995

The affinity of mequitazine, a non-sedating antihistamine, for muscarinic receptors was evaluated in the guinea-pig ventricle and ileum by in vitro binding techniques and functional studies. In binding studies, [$^3$H]quinuclidinyl benzilate (QNB) identified a single class of muscarinic receptors with similar apparent $K_{D}$ value of about 100 pM in two tissues. Mequitazine inhibited [$^3$H]QNB binding to muscarinic receptors competitively. Analysis of the mequitazine inhibition curve of [$^3$H]QNB binding to ventricular microsome and ileal homogenate indicated the presence of a single homogeneous binding site with Ki value of 25 nM and 18 nM, respectively. In functional studies, mequitazine caused parallel rightward shifts of concentration-response curves for carbachol and histamine in the isolated guinea-pig ileum. The slope values obtained from Schild plot analysis for the antagonistic action of mequitazine on muscarinic and histamine $H_1$-receptors were not significantly different from unity. The p $A_2$values of mequitazine for muscarinic and histamine $H_1$-receptors were about 7.6 ( $K_{M}$= 25.1 nM) and 8.88 ( $K_{H}$= 1.32 nM), respectively. These results indicate that the muscarinic receptor blocking action of mequitazine is 15 times less potent than the $H_1$receptor blocking action, but high concentration of this drug may cause the peripheral muscarinic receptor blocking effect.t.t.t.

• 대한약리학회지
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• 제11권2호
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• pp.9-17
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• 1975

The adrenergic blocking activity and refractory period of cardiac muscle on isolated rabbit atria were measured after administration of Scutellaria. In rabbits and cats the antiarrhythmic action of Scutellaria on atrial and ventricular arrhythmias produced by epinephrine or ouabain was examined and also compared with that of propranolol and quinidine. The alcoholic extract of Scutellaria produced a marked decrease in heart rate and contractile amplitude of the isolated rabbit atria. Pretreatment with Scutellaria rendered the atria to fail to respond to epinephrine, indicating that this crude drug possesses an adrenergic blocking activity. The extract produced a marked prolongation of the refractory period of atrial muscle. The extract effectively abolished the spontaneous arrhythmia occurring in the isolated rabbit atria. As propranolol and quinidine it also suppressed the atrial arrhythmia induced by ouabain. The extract prevented, as propranolol and quinidine, the induction of ventricular arrhythmia arising from excessive dose of epinephrine in anesthetized rabbits and cats. With regard to the ventricular arrhythmia induced by a continuous infusion of ouabain, the alcoholic extract of Scutellaria exerted some suppressive effect in anesthetized rabbits but no effect on cats. From the above results, it may be concluded that Scutellaria is effective against atrial and ventricular arrhythmias. The antiarrhythmic effects of this drug may be the result of adrenergic beta receptor blocking and cardiac depressive activities including prolongation of the refractory period of cardiac muscle.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -2
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• pp.1038-1041
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• 2002

In this paper, we have proposed a novel trench electrode Base Resistance Thyristor(BRT) and trench electrode BRT with a intrinsic region. A new power BRTs have shown superior electrical characteristics including snab-back effect and forward blocking voltage more than the conventional BRT Especially, the trench electrode BRT with intrinsic region has obtained high blocking voltage of 1600V. The blocking voltage of conventional BRT is about 400V at the same size. Because the breakdown mechanism of BRT is avalanch breakdown by impact ionization, the trench electrode BRT with intrinsic region has suppressed impact ionization, effectively. If we use this principle, we can develope super high voltage power device and applicate to another power device including IGBT, EST and etc,

• Journal of Advanced Marine Engineering and Technology
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• 제23권2호
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• pp.159-167
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• 1999

This paper presents a new transient voltage blocking device(TOBD)which low power and high frequency bandwidth to protect info-communication facilities from transient voltages. Conventional protection devices have some problems such as low frequency bandwidth low ener-gy capacity and high remnant voltage. in order to improve these limitations a hybrid type TOBD which consists of a gas tube avalanche diodes and junction type field effect transistor (JFETs) is developed. The TOBD differs from the conventional protection devices in configuration and JFETs are used as an active non-linear element and a high speed switching diode with low capacitance limited high current. Therefore the avalanche diode with low energy capacity are protected from the high current and the TOBD has a very small input capacitance. From the performance test using combination surge generator which can produce $1.2/50{\mu}m$ 4.2 kV/max, $8/20{\mu}m$ 2.1 kAmax it is confirmed that the proposed TOBD has an excellent protection per-formance in tight clamping voltage and limiting current characteristics.

• 통합자연과학논문집
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• 제11권1호
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• pp.1-8
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• 2018

HEMA, AA, MMA, and EGDMA as crosslinking agent and AIBN as an initiator, and 2,4-dihydroxybenzophenone, 2-ethylhexyl-trans-4-methoxy-cinnamate, 2-hydroxy-4-(methacryloyloxy)benzophenone as additives at 0.1-1.0% ratios were used to manufacture hydrophilic ophthalmic lenses through thermal polymerization before their physical properties were measured. The results showed that the samples containing of 2,4-dihydroxybenzophenone and 2-ethylhexyl-trans-4-methoxy-cinnamate resulted in a decrease of the UV blocking performance after high-pressure sterilization whereas the sample containing 2-hydroxy-4-(methacryloyloxy)benzophenone showed no change in the UV blocking performance. It is judged that this is induced by presence or absence of an acyl functional group in benzophenone.

• 생명과학회지
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• 제12권5호
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• pp.549-554
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• 2002

포공영약침액의 암억제 효과를 살펴보기 위하여 quinone reductase (QR) 생성유도를 생쥐의 간암세포인 Hepa Iclc7를 이용하여 측정한 결과, 포공영약침액을 처리한 Hepa Iclc7에서 QR생성이 유도되었다. 또한 포공영약침액은 phase II detoxification 효소인 glutathione S-transfer-ase (CST) 활성을 증가시키고 glutathione 생성도 증가시켰다 QR과 CST는 간세포에서 주로 생성되는 phase II효소로 발암물질에 의해 일어나는 돌연변이와 종양화 효과를 막아주고 발암물질을 무독화 시키는 것으로 알려져 있다. 따라서 본 실험에서 포공영약침액은 QR 효소 생성 유도, glutathione 함량 증가 및 CST 효소활성 증대등 phase II detoxification의 기작을 통한 발암과정의 blocking agent로서 효과가 있음을 알 수 있었다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2012년도 추계학술대회
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• pp.251-254
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• 2012

본 논문에서는 양자 우물 구조 변화에 따른 GaN 기반 LED의 출력 특성을 분석하였다. 사용된 LED의 기본 구조는 GaN 버퍼층을 기반으로 GaN 장벽과 InGaN 양자 우물로 이루어진 활성 영역이 AlGaN EBL(Electron Blocking Layer)과 AlGaN HBL(Hole Blocking Layer) 사이에 구성되어 있다. ISE-TCAD를 이용하여 LED 활성영역의 양자 우물의 두께와 개수, 장벽의 도핑 변화에 따른 출력 전력, 내부 양자 효율 특성을 분석하였다.