• Bulletin of the Korean Chemical Society
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• 제32권2호
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• pp.483-488
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• 2011

Present work comprises of synthesis various analogues of ciprofloxacin by introducing new functionality at carboxylic group position via ester aminolysis reaction. For this purpose the carboxylic group at C-3 was esterified and later subjected to nucleophilic attack at the carbonyl carbon by various aromatic amines. Structure of the analogues was confirmed by different techniques i.e. IR, $^1H$ NMR and mass spectrometry. The antibacterial activity of the derivatives was also assessed with the parent against a series of Gram-positive and Gram-negative bacteria. The synthesized compounds showed diverse antimicrobial profile among which most compounds possessed a comparable or better activity in comparison to the ciprofloxacin. Additionally unlike ciprofloxacin, some of the derivatives were also found to show antifungal activity.

• Bulletin of the Korean Chemical Society
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• 제30권10호
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• pp.2294-2298
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• 2009

In present work an attempt was made to synthesize various analogues of levofloxacin by introducing new functionality at carboxylic group position via nucleophilic substitution reaction. For this purpose the carboxylic group at C-6 was esterified and later subjected to nucleophilic attack at the carbonyl carbon by various aromatic amines. Structure of the analogues was confirmed by different techniques i.e. IR, $^1H$ NMR and mass spectrometry. The antibacterial activity of the derivatives was also assessed and compared with the parent against a series of Gram-positive and Gramnegative bacteria. A synergistic as well as antagonistic behavior was observed in these derivatives. Additionally unlike levofloxacin, the derivatives were also found to modulate oxidative burst response of phagocytes exhibiting moderate to significant inhibitory activity.

• Bulletin of the Korean Chemical Society
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• 제34권11호
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• pp.3372-3376
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• 2013

The kinetic studies on the reactions of ethyl methyl (2) and ethyl propyl (4) chlorothiophosphates with X-pyridines have been carried out in acetonitrile at $35.0^{\circ}C$. The free energy correlations with X show biphasic concave upwards with a break point at X = H (2) and 3-Ph (4), respectively. A stepwise mechanism with a rate-limiting leaving group expulsion from the intermediate is proposed based on the magnitudes of selectivity parameters for both substrates. The considerably large values of ${\beta}_X$ = 1.50(2) and 1.44(4) with strongly basic pyridines and relatively small values of ${\beta}_X$ = 0.43(2) and 0.36(4) with weakly basic pyridines are interpreted as a change of the attacking direction of the X-pyridines from a frontside to a backside attack toward the chloride leaving group.

• Endocrinology and Metabolism
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• 제33권4호
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• pp.429-434
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• 2018

As diagnostic techniques have advanced, primary aldosteronism (PA) has emerged as the most common cause of secondary hypertension. The excess of aldosterone caused by PA resulted in not only cardiovascular complications, including coronary artery disease, myocardial infarction, arrhythmia, and heart failure, but also cerebrovascular complications, such as stroke and transient ischemic attack. Moreover, PA is associated more closely with these conditions than is essential hypertension. In this review, we present up-to-date findings on the association between PA and cerebrovascular diseases.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.452-455
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• 2008

Model Scramjet engine is tested with T4 free-piston shock tunnel at University of Queensland, Australia. Basically, test condition is fixed as Mach 7.6 at 31 km altitude. With this condition, variation effects of fuel equivalence ratio, cavity, cowl setting and angle of attack were investigated. In the results, supersonic combustion was observed with low and middle fuel equivalence ratio. At high equivalence ratio, thermal choking was occurred due to the intensive reaction. Cavity and W-shape cowl showed early ignition and enhanced mixing respectively.

• Journal of Korean Neurosurgical Society
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• 제30권6호
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• pp.729-733
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• 2001

Objective : Antifibrinolytic treatment after aneurysmal subarachnoid hemorrhage has been shown to have no significant effect on outcome since a reduction in the rate of rebleeding was offset by an increase in the incidence of hydrocephalus and ischemic events. As the results of early aneurysm surgery and a change of strategy in the intensive medical treatment, outcome in patients with cerebral ischemia has been improved. On the other hand, rebleeding still remains as a major cause of death. A short course of tranexamic acid(TA) was tried to study its efficacy and safety in reducing the incidence of rebleeding before aneurysm surgery. Methods : A total of 507 patients with ruptured cerebral aneurysm operated within 3 days after the attack from 1990 to 1999 were included in this study. Group A consisted of 302 consecutive patients treated from 1990 through 1995 served as control. Two hundred-five patients in group B were treated with TA from 1996 through 1999. Both groups were evaluated for comparability of demographic and clinical variables including age, Hunt-Hess grade, Fisher grade, aneurysm location, hypertension, day of surgery, and initial hydrocephalus. The relationships of TA with rebleeding, ischemia, and chronic hydrocephalus were also studied. Results : There was no significant difference in patient demographics and clinical characteristics between group A and group B. Sixteen patients(5.3%) suffered a recurrent hemorrhage in group A and three(1.5%) in group B(p<0.05). Chronic hydrocephalus requiring a shunt was found in a significantly greater proportion in group B than in group A(p<0.05). The incidence of cerebral ischemia was not elevated in group B compared with group A. Conclusion : Considering the fact that the reduction of fatal rebleeding outweighed the increased incidence of hydrocephalus, the authors believe that a short course of TA is beneficial in diminishing the risk of rebleeding prior to early surgical intervention.

• 동의신경정신과학회지
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• 제8권1호
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• pp.151-165
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• 1997

The primary purpose of this study was to assess the relation of stress perception and poststroke. This study was done on 50 stroke patients in hospital. According to activities of functional impairment, they were classified into walking disturbance, motor weakness, dysphagia, or reattack etc. The stress perception test(GARS Scles) and stress response assessment shows the follwing results. 1. On the distribution in the stroke 50 patients, For the majority group were male in sex, sixty inage, middle towns people in residence. 2. On the comprehensive GARS scale scores, It marked the higest scores thirty at age, merchandise or salesman on jobs, a city in residence. There was no signigicant difference in mean GARS Scales scores between males and females group, the left hemiplegia and the Rt hemiplegia. 3. On the comprehensive GARS Scale tests, Overall glogal stressor(G8) and sickness stresor(G4) marked the highest scores of all GARS Scales. 4. On the comparative assessment of each group's stress reponse test scores, zung-bu(中腑) was showed higher scores than the other group in oriental diagnosis and hemorrage was showed higher scores than the other group in western medical diagnosis. 5. On the comprehensive assessment of each group's stress reponse test scores, aphsia(不語) marked the highest scores in another disphagia group's. It marked the highest scores in another group's that banshinbulsoo(半身不遂) as regards as hemiplegia generally. Standing disability is the higher scores than another group's walking alone or assist, and standing alone. 6. Secondary attack is the highest scores of all reattack stroke on the stress repones test. 7. Comparing and analyzing the GARS Scale total scores and GARS Scale subject fator at stroke, we found that sickness stressor and fininial stressor is showed the highest correlated to stress response fowlloing stroke. With those results, we can see that functional impairment following stroke is correlated to stress perception and reponse. In the furture studies using, we hope that the findings the study would have clinical relevance to the psychosocial adjustment and total rehabilation of stroke patients.

• 대한한방내과학회지
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• 제25권4호
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• pp.65-74
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• 2004

Object : This is a study of acute stage stroke patients designed for comparison of combined Eastern and Western medical treatments and Oriental treatments alone. Methods : 51 patients were diagnosed by Brain-CT and Brain-MRI scan as having suffered stroke. They had entered Dong-eui hospital within seven days of attack, and remained over seven days, all between November 2002 and August 2003. Patients were divided into two groups: a group treated with both Eastern and Western medical treatments, and a group treated only with Oriental medical treatments (but examinations were done and medications were given in hypertension, Diabetes Mellitus and so on). Results : The Eastern-Western medical treatment group showed significant changes in NIHSS. A rate of improvement figure of 24.94% was obtained for the Eastern-Western medical treatment group, and for the Oriental medical group a figure of 7.84% was obtained. Conclusion : The East-West medical treatment group had significant rate of development that measure for NIHSS by treated comparatively dependent patients. And oriental medical treatment group had significant rate of development that measure for NIHSS by treated comparatively independent patients. The NIHSS measure for the Eastern-Western medical treatment group shows a significant rate of improvement for relatively dependent patients, and the NIHSS measure for the Oriental medical treatment group shows a significant rate of development for relatively independent patients.

• 정보보호학회논문지
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• 제19권3호
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• pp.119-131
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• 2009

세계적으로 통용되고 있는 키 교환 프로토콜은 TLS/SSL 등의 공개된 암호 통신프로토콜인 반면에 국내 금융권에서는 공인인증과 더불어 금융권에 적합한 공개키 기반 구조(PKI: Public Key Infrastructure)를 이용한 키 교환 프로토콜을 민간 주도로 개발하여 사용하고 있다. 하지만 금융권에서 사용하고 있는 키 교환 프로토콜은 클라이언트 위장공격(client impersonation attack)과 기지 키 공격(known-key attack)에 취약하며, 전방향 안전성 (forward secrecy)을 제공하지 않는다. 특히, 암호문과 서버 측 개인키(예: RSA 개인키)만 있으면 쉽게 과거의 세션키(session-key)를 알아내 암호화된 메시지를 복호화 할 수 있기 때문에, 만약 내부 관리 등의 문제로 인해 금융보안 서버의 개인키 유출 시 막대한 개인정보와 금융정보가 노출될 우려가 있다. 본 논문에서는 금융권에 사용 중인 암호 통신 프로토콜의 취약점을 분석하고, 국내 환경에 적합하도록 프로토콜 교체 비용을 최소화하면서 클라이언트 위장 공격과 세션키 노출 및 개인키 유출 사고에도 안전한 두 개의 키 교환 프로토콜을 제안한다. 또한 제안하는 두 번째 프로토콜이 HDH(Hash Diffie-Hellman) 문제가 어렵다는 가정 하에 증명 가능한 전방향 안전성을 제공함을 보인다.

• 정보처리학회논문지C
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• 제13C권7호
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• pp.913-922
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• 2006

주파수공용통신(TRS: Trunked Radio Service)이란 무선통신을 하는 사람이 특정한 주파수를 이용하던 종래의 무선통신방식과는 달리 중계소에 할당된 소수의 주파수를 다수의 이용자가 공동으로 사용하는 방식을 말한다. TRS 시스템의 가장 큰 특징은 일대 다수의 그룹 및 지령 통신방식이다. TRS 시스템의 구성은 여러 개의 그룹으로 구성되며, 각 그룹은 업무내용에 관련된 유사한 목적을 가진 사용자들의 단말기로 구성된다. 위와 같은 여러 목적에 따라 다양한 형태의 연결이나 그룹 통신이 이뤄질 경우, 여러 가지 형태의 공격에 노출될 수 있으며, 대규모 통신을 위한 키 분배 혹은 설정에 많은 문제점을 가질 수 있다. 본고에서는 TRS 상에서 안전한.통신을 수행하는데 있어 필수 요소인 그룹 키 분배방식을 고찰하며, 통신 횟수를 줄이면서도 참여자 인증을 수행할 수 있는 효율적인 그룹 키 분배 방식을 제안하였다.