• Biomolecules & Therapeutics
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• 제18권4호
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• pp.363-374
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• 2010

Growing evidence suggests a prominent role for leptin in human cancer progression. The intricate pattern of leptin cross-talk with other associated signaling pathways is a critical area of research that will ultimately contribute to comprehending the role of leptin in cancer progression. This review summarizes a portion of the current understanding of leptin signaling, with a critical focus on its contribution to tumor cell invasion and metastasis. Five topics are addressed in this review: (1) Leptin receptor, (2) Leptin signaling, (3) Leptin and cancer, and (4) Leptin and tumor invasion. Due to the complex cellular effects of leptin, a more precise understanding of leptin signaling pathways must still be elucidated. Leptin is clearly a major factor for stimulating tumor progression through a complex spectrum of interplay and cross-talk among various signaling molecules. An understanding of the role of leptin in invasion and metastasis will provide valuable information for establishing strategies to modulate leptin signaling, which should be a high priority for the development of anti-cancer therapeutics.

• 대한조선학회지
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• 제17권2호
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• pp.1-10
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• 1980

The optimal plastic design of framed structures has been treated as the minimum weight design while satisfying the limit equilibrium condition that the structure may not fail in any of the all possible collapse modes before the specified design ultimate load is reached. Conventional optimum frame designs assume that a continuous spectrum of member size is available. In fact, the vailable sections merely consist of a finite range of discrete member sizes. Optimum frame design using discrete sections has been performed by adopting the plastic collapse theory and using the Complex Method of Box. This study has presented an iterative approach to the optimal plastic design of plane structures that involves the performance of a series of minimum weight design where the limit equilibrium equation pertaining to the critical collapse mode is added to the constraint set for the next design. The critical collapse mode is found by the collapse load analysis that is formulated as a linear programming problem. This area of research is currently being studied. This study would be applied and extended to design the larger and more complex framed structures.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 A
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• pp.212-215
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• 1995

In this paper, The characteristic of Harmonic spectrum is studied for generally used three-phase diode rectifier. and filter design criteria is showen in the sense of THD, DPF, and PF. As the becoming of Automative and informative era, the demand of critical and stable control becomes more and more important. But much EMI emissions are generated for more critical and stable control in power electronic system these EMI emissions can be measured using LISN(Line Impedance Stabilization Network). So we are to investigate the behavior of Conducted EMI emission in Diode Rectifiers using LISN in frequency domain.

• Tuberculosis and Respiratory Diseases
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• 제69권4호
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• pp.237-242
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• 2010

Pulmonary vascular disease is a category of disorders, including pulmonary hypertension, pulmonary embolism or chronic thromboembolic pulmonary hypertension, pulmonary vasculitis, pulmonary vascular disease secondary to chronic respiratory disease, and pulmonary vascular tumor and malformations. This article reviews the recent advances in this wide spectrum of pulmonary vascular diseases.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.181.2-181.2
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• 2003

Inosine monophosphate dehydrogenase(IMPDH) catalyzes the $NAD^+$-dependent oxidation of IMP to XMP, the rate limiting step in the de novo biosynthesis of guanine nucleotide. Its critical role at the metabolic branch point in purine nucleotide biosynthesis makes it a useful target in the development of drugs for antiviral and anticancer chemotherapy and in immunosupressant area. Several compound with antiviral activity have been found to be inhibitors of IMPDH. For example, ribavirin, a competitive inhibitor of IMPDH, has broad spectrum antiviral activities against DNA and RNA viruses. (omitted)

• Asian-Australasian Journal of Animal Sciences
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• 제16권5호
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• pp.726-731
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• 2003

The aim of this research was to identify candidate probiotic lactic bacteria among indigenous dadih lactic isolates. Dadih is an Indonesian traditional fermented milk of West Sumatra which is fermented naturally. Viability of the strain is critical in determining the capacity of lactic bacteria to induce immune stimulation as well as to colonize in the intestinal tract. Therefore, LAB are proposed to exert health promoting or probiotic effects in human, such as inhibition of pathogenic microflora, antimutagenic, and the reduction of cholesterol levels. This manuscript reports in vitro probiotic properties of indigenous dadih lactic bacteria, especially some important colonization factors in GI tract, such as lysozyme, acid and bile tolerance. Bile Salt Hydrolase (BSH) activity, spectrum of bacteriocin, and antimutagenic activity of bacterial cells were also assessed. Twenty dadih lactic isolates were screened further for their tolerance to low pH, at pH 2 and 3 as well as their bile tolerance. There were ten isolates classified as acid and bile acid tolerant, and further screened for lysozyme tolerance, BSH activity. The spectrum of bacteriocin activity of isolates was assayed using cell-free neutralized supernatants by agar spot test against variety of pathogens. Lc. lactis subsp. lactis IS-10285, IS-7386, IS-16183, IS-11857 and IS-29862, L. brevis IS-27560, IS-26958 and IS-23427, Leu.mesen.mesenteroides IS-27526, and L. casei IS-7257 each has good survival rate at low pH values and in the presence of lysozyme, and short lag time in the presence of 0.3 % oxgall. Lc. lactis subsp. lactis IS-11857 and IS-29862 each has high BHS activity, Lc. lactis subsp. lactis IS-10285 and IS-16183 each had a positive spectrum of bacteriocin activity against E. coli 3301 and Lysteria monocytogenes ATCC 19112, while L. brevis IS-26958 has high BHS activity as well as positive spectrum of bacteriocin against E. coli 3301, Lysteria monocytogenes ATCC 19112, and S. aureus IFO 3060. All of the ten dadih lactic strains performed in vitro acid and bile tolerance, indicating a possibility to reach the intestine alive, and display probiotic activities.

• 한국정보통신학회논문지
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• 제3권3호
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• pp.485-499
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• 1999

1989년 뉴질랜드에서 전파관리에 시장메커니즘이 도입된 이후 전세계적으로 동 방식에 대한 관심이 증대되고 있으며, 그 도입도 점차 확산되고 있다. 이러한 추세에 따라 한국에서도 전파관리에 시장메커니즘 도입에 관한 논의가 최근 들어 활발하게 이루어지고 있다. 이와 같은 배경 하에서 최근 정보통신부가 입법예고한 전파법 개정(안)에는 주파수에 재산권을 도입하고, 도입된 주파수 재산권을 경매방식을 통하여 배분하는 내용이 포함되어 있다. 경매는 자원의 가격결정과 배분이라는 두 가지 문제를 풀기 위해 적용될 수 있기 때문에 매력적인 시장방식의 메커니즘으로 인식되고 있다. 그럼에도 불구하고 경매방식의 유효성은 주파수 재산권 배분에서 당연한 것으로 받아들여져서는 안될 것이다. 경매가 잘 못 설계될 경우 당초에 의도하였던 것과는 달리 비효율적인 주파수 배분이 이루어 질 수도 있게 될 뿐만 아니라, 전파관리에 부정적인 영향을 줄 수 있기 때문이다. 본 논문에서는 주파수 재산권 경매방식 설계시 고려해야 할 핵심요소와 논점들을 기존의 경매이론과 주요국의 경험을 토대로 논의하였다.

• 생물정신의학
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• 제21권4호
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• pp.118-127
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• 2014

Along with language, socialization is a unique feature of the human being. There is a continuous debate regarding whether the development of socialization is innate, and conducted by the environment in the growing process, or the result of the interaction of both aspects. If socialization is the result of the interaction with the environment or is an acquired developmental process, the following question rises. "Is there a 'critical period' for the development of socialization?" Although there are a huge number of studies seeking for treatment and solutions for developmental delay or deficits of socialization, it is very complicated question to answer. Historical figures such as 'Hugh Blair' of Borgue in England, and 'the wild boy of Aveyron' in France, seem to have innate socialization deficits. Nowadays patients with non-verbal learning disorder, social communication disorder, or autism spectrum disorder seem to have genetic defects. On the other hand, Harry Harlow's monkey experiments, hikikomori of Japan, Romanian orphans and patients with reactive attachment disorder seem to display social deficits due to environmental factors. However, it is not easy to clearly draw a line between innate or acquired factors. Therefore, rather than subdividing the diseases for etiological and pathophysiological approach to heterogenous groups with the common denominator of social deficit, and for the research of pathophysiology and treatment development, the authors suggest a comprehensive concept of "social dysfunction spectrum."

• 한국위성정보통신학회논문지
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• 제7권1호
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• pp.39-47
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• 2012

현재의 주파수 분배상황을 살펴보면 대부분의 주파수 대역이 고정 할당되어 있으며 특히 무선통신 환경에 가장 적합한 저주파 대역은 거의 사용할 여지가 없다. 이에 인지무선 기술은 무선통신환경에서 주파수 부족 문제를 해결하고 주파수 활용도를 높이기 위한 중요한 기술로 대두되고 있다. 본 논문에서는 SDR (Software Define Radio)플랫폼인 USRP (Universal Software Radio Peripheral) 보드와 SDR 개발 툴킷인 GNU Radio를 이용하여 실제 인지무선(Cognitive Radio : CR) 시스템에서 데이터를 송, 수신하였다. 구체적으로 스펙트럼 센싱 기술을 이용하여 면허 사용자의 주파수 사용 여부를 감지하여 이 정보를 데이터베이스로 넘겨준다. 정보를 넘겨받은 데이터베이스에서는 유전자 알고리즘을 이용하여 최적의 송신전력과 대역폭, 채널 정보를 인지무선 기기에 보내어 주어 인지무선 기기가 면허 사용자에게 아무런 간섭을 주지 않고 데이터 통신을 할 수 있도록 하였다.

• 한국위성정보통신학회논문지
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• 제6권2호
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• pp.72-77
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• 2011

스펙트럼 센싱은 인지무선통신(CR, Cognitive Radio) 네트워크를 구성함에 있어 핵심적인 기술 중에 하나이다. 2차 사용자인 CR사용자는 1차 사용자에게 간섭을 주지 않기 위해 스펙트럼을 센싱 하여 해당 채널이 비어있거나 규정된 레벨 이하일 경우에만 해당 채널을 사용하게 된다. 최근 스마트폰의 사용으로 데이터의 트래픽이 증가함에 따라 광대역 서비스가 급증하고 있으며, 그에 따라 한 번에 넓은 대역을 센싱하는 광대역 센싱 기법의 필요성이 점차 높아지고 있다. 이러한 광대역 센싱은 인지무선통신이 수행되기 위한 매우 중요한 기술 중 하나이다. 높은 분해능을 갖는 광대역 센싱을 수행하기 위해서는 신뢰 할 수 있는 신호를 얻기 위한 알고리즘 처리가 선행되어야 한다. 따라서, 본 논문에서는 채널 상태가 좋지 않은 부 대역을 제외한 나머지 대역을 CR 사용자가 각각 센싱하여 정보를 취합하여 1차 사용자의 유무를 결정하는 협력 센싱 기법을 제안하였다. 이 때, 신호의 신뢰성을 높이기 위해 각각의 부 대역으로 나눈 CSI(Channel State Information)를 이용하여, 채널 상태를 파악한다. 또한, 검출 기법으로는 시스템 복잡도를 감소시키기 위하여 에너지검출 기법을 사용한다. 모의실험을 통해 성능을 검증하였고 그 성능은 SNR(Signal Noise ratio)에 따른 검출 확률로 나타내었다.