• Journal of Power Electronics
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• 제9권2호
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• pp.198-206
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• 2009

An algorithm is developed that enables a single-phase matrix converter (SPMC) to perform functions of a generalized single phase power electronics converter such as acting as a frequency changer, rectifier, inverter, and chopper. This reduces the need for new converter hardware. The algorithm is implemented first on computer simulation software Orcad Capture CIS version 9.1. Simulation results are presented for five types of converters with a control input variable that decides the 1) type of converter and 2) type of output waveform. The simulated results verify the working and operation of a generalized converter based on SPMC. Simulated results are verified with experimental results. Hardware design is obtained using readily available ICs and other components. The trigger circuit has been tested qualitatively by observing waveforms on CRO. The operation of the proposed system has been found to be satisfactory.

• 대한전기학회논문지
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• 제35권9호
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• pp.375-379
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• 1986

The HCP(Hypocycloidal Pinch) device for plasma focus was modified for a pumping source of the dye laser, and the spectral distribution and time behavior of its light pulses were investigated by using a UV spectrometer, 70 MHz CRO and Si-PIN photodiode detector. An array of multiple stages of HCP and narrower electrode gaps were chosen in order to make a more uniform discharge along the HCP axis. The possible spectral range for the pumping of dye laser is 360-620nm, when the HCP is operated at 5-8kv of apllied voltage and 50-150Torr of Ar fill gas pressure. The rise-time and FWHM of light pulses from the HCP are 5us and 30-50us respectively when it is operated under the same conditions as above.

• International Journal of Automotive Technology
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• 제6권2호
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• pp.161-169
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• 2005

Neck injuries sustained during low speed rear impact are the most commonly sustained traffic injury. Therefore, the analysis of neck injury mechanisms and methods for mitigating and reducing neck injuries during low speed rear impact are a very important issue in the vehicle safety field. In order to find a method to absorb the shock that is transmitted to the occupant, the response of frontal and rear dummy due to the motion of the struck vehicle and the rotational angular displacements of dummies' necks during rear impact at 12km/h speed were investigated using a Working Model 2D. The results suggest that the shock absorption system should be equipped in the bottom of the seat of the vehicle to reduce shock and mitigate neck injury to the occupants.

• Journal of Nutrition and Health
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• 제46권3호
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• pp.226-238
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• 2013

Omega-3 polyunsaturated fatty acids are essential fatty acids because humans cannot synthesize them de novo and must obtain them in their diet. Fish and fish oil are rich sources of omega-3 fatty acids, including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Significant evidence of the beneficial role of dietary intake of omega-3 fatty acids in blood flow has been reported and putative mechanisms for improvement of blood flow include anti-thrombotic effects, lowered blood pressure, improved endothelial function, and anti-atherogenic effects. Edible oils containing omega-3 fatty acids were registered as functional ingredients in the Korea Health Functional Food Code. Although omega-3 fatty acids have been evaluated by the Korea Food and Drug Administration (KFDA) based on scientific evidence, periodic re-evaluation may be needed because emerging data related to omega-3 fatty acids have accumulated. Therefore, in this study, we re-evaluated scientific evidence for the effect of omega-3 fatty acids as a functional ingredient in health functional food on improvement of blood flow. A comprehensive literature search was conducted for collection of relevant human studies using the Medline and Cochrane, KISS, and IBIDS databases for the years 1955-2012. Search keywords were used by combination of terms related to omega-3 fatty acids and blood flow. The search was limited to human studies published in Korean, English, and Japanese. Using the KFDA's evidence based evaluation system for scientific evaluation of health claims, 112 human studies were identified and reviewed in order to evaluate the strength of the evidence supporting a relation between omega-3 fatty acids and blood flow. Among 112 studies, significant effects on improvement of blood flow were reported in 84 studies and the daily intake amount was ranged from 0.1 to 15 g. According to this methodology of systematic review, we concluded that there was possible evidence to support a relation between omega-3 fatty acid intake and blood flow. However, because inconsistent results have recently been reported, future studies should be monitored.

• Nutrition Research and Practice
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• 제12권5호
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• pp.371-377
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• 2018

BACKGROUND/OBJECTIVES: Elevation of postprandial lipemia characterized by a rise in triglyceride (TG)-rich lipoproteins can increase the risk of atherogenesis. The objective of this study was to investigate postprandial lipemia response to a single dietary fat/sugar load test and monitor beneficial changes induced by the consumption of Platycodi radix (AP) beverage in healthy subjects. SUBJECTS/METHODS: A total of 52 subjects were randomly assigned to either placebo or AP beverage group with a high-fat shake in a randomized controlled crossover trial. Postprandial blood was collected at 0, 1, 2, 4, and 6 h and analyzed for TG and lipoprotein lipase mass. Inhibition of pancreatic lipase was determined in vitro. RESULTS: AP inhibited pancreatic lipase activity in vitro ($IC_{50}=5mg/mL$). Compared to placebo beverage, AP beverage consumption with a high-fat shake induced significant increase of plasma lipoprotein lipase mass (P = 0.0111, ${\beta}$ estimate = 4.2948) with significant reduction in very low-density lipoprotein (VLDL) TG concentration (P = 0.038, ${\beta}$ estimate = -52.69) at 6 h. Based on significant correlation between high-fat dietary scores MEDFICTS and postprandial TG responses in VLDL (P = 0.0395, r = 0.2127), subgroup analysis revealed that 6 h-postprandial VLDL TG response was significantly decreased by AP consumption in subjects with MEDFICTS ${\geq}40$ (P = 0.0291, ${\beta}$ estimate = -7214). CONCLUSIONS: AP beverage might have potential to alleviate postprandial lipemia through inhibiting pancreatic lipase activity and elevating lipoprotein lipase mass. Subgroup analysis revealed that subjects with high-fat dietary pattern could be classified as responders to AP beverage among all subjects.

• 한국식품영양과학회지
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• 제43권2호
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• pp.293-299
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• 2014

글루코사민의 관절건강 기능성을 건강기능식품 재평가 기준에 맞추어 체계적 고찰을 실시하였다. 2012년 5월 기준 DB 검색을 통해 703건의 자료를 수집하여, 선정/제외 기준에 따라 선별한 결과 총 34건의 연구가 평가되었다. 34건 중 28건(4,225명)의 연구에서 통계적으로 유의한 개선 효과가 나타났으며(P<0.05), 일일 섭취량은 1.5~2 g으로 공전에서 제시되어 있는 섭취량 범위에 해당하였다. 글루코사민의 기능성 재평가 이후의 연구 결과는 16건이었고, 이 중 1,158명 대상 14건의 연구에서 유의한 관절건강 개선효과를 보였다(P<0.05). 연구대상자에 따른 분석 결과, 방사선 검사 기준에 따라 관절 연골의 손상 정도가 심한 대상자를 제외한 연구는 11건이었으며, 이 중 2,934명 대상 10건의 연구에서 글루코사민이 관절건강에 유의한 개선 효과를 보였다(P<0.05). 따라서 현시점에서 건강기능식품인 글루코사민의 관절건강 기능성은 인정될 것으로 판단되나 향후 연구 결과 추이를 지속적으로 지켜볼 필요가 있다.

• Journal of Nutrition and Health
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• 제47권1호
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• pp.45-50
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• 2014

생강 건조 분말의 임신 또는 멀미로 인해 발생하는 오심, 구토 개선 기능성을 평가하기 위하여 체계적 고찰을 실시하였다. 2013년 3월 기준으로 DB 검색을 통해 870건의 자료를 수집하여, 선정/제외 기준에 따라 선별한 결과 총 12건의 연구가 평가되었다. 12건 (2,694명) 중 11건 (2,630명)의 연구에서 통계적으로 유의한 개선 효과 나타났으며 (p < 0.05), 효과를 보이는 일일 섭취량은 0.25~2.5 g이었다. 특히 임신부 대상 연구 9건에서는 모두 유의한 개선 효과를 보였고, 멀미에 대한 효과를 관찰한 3건의 연구 중 1,741명을 대상으로 한 대규모 연구 1건을 포함한 2건에서 구토를 유의하게 개선시키는 것으로 보고되었다. 해당 연구에서 모두 생강섭취로 인한 이상 반응은 없는 것으로 확인되었다.

• 생명과학회지
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• 제14권1호
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• pp.121-125
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• 2004

E. coli에서 B. macerans 유래 cyclodextrin glucanotransferase (CGTase)의 활성형 생산에 GroEL/ES chaperone과의 공발현과 저온 배양의 공동작용 효과에 대해 조사하였다. 실험에 사용된 cgt와 groEL/ES 유전자를 발현하는 pTCGTl과 pGroll은 각각 T7 promoter와 Pzt-1 promoter에 의해 조절되고 이들을 E. coli에 도입시켰다. 대수증식기 초기(2 hr)와 대수증식기 중기(3 hr)에 tetrarycline 10 ng/ml 과 IPTG 1 mM을 첨가하여 각각의 유전자를 발현시켰다. CGTase활성과 specific artivity 측정 시 $37^{\circ}C$에서 pTCGTl 단독 발현 보다 $25^{\circ}C$에서 chaperone과 함께 발현시킨 경우 2배나 높은 활성이 측정됐으며, SDS-PACE 분석결과 $37^{\circ}C$에서 단독 발현 시킬경우 20% 정도 가용성 형태로 발현되던 것이 $25^{\circ}C$에서 chaperone과 공발현 시에는 거의 3.5배가 넘는 69%가 가용성으로 전환됨을 알 수 있었다. 이와 같이 분자 chaperone과 $25^{\circ}C$에서의 저온 배양은 E. coli에서 활성형질 가용성 CGTase의 생산 증가에 큰 영향을 미치는 것으로 나타났다.

• Journal of Microbiology and Biotechnology
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• 제12권3호
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• pp.508-513
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• 2002

Human endogenous retroviral long terminal repeats (LTRs) have been found to be coexpressed with sequences of genes located nearby. It has been suggested that the LTR elements have contributed to the structural change or genetic variation of human genome connected to various diseases. The HERV-W family has been identified in the cerebrospinal fluids and brains of individuals with schizophrenia. Using a cDNA library derived from a human brain, the HERV-W LTR elements were examined and five new LTR elements were identified. These elements were examined using a YAC clone panel from the Xq21.3 region linked to psychosis that was replicated on the Y chromosome after the separation of the chimpanzee and human lineages. Fourteen elements of the HERV-W LTR were identified in that region. Those LTR elements showed a high degree of sequence similarity ($91.8-99.5\%$) with previously reported HERV-W LTR. A phylogenetic tree obtained from the neighbor-joining method revealed that new HERV-W LTR elements were closely related to the AXt000960, AF072504, and AF072506 from the GenBank database. The data indicates that several copy numbers of the HERV-W LTR elements exist on the Xq21.3 region and are also expressed in the human brain. These LTR elements need to be further investigated as potential leads to neuropsychiatric diseases.

• 응용통계연구
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• 제21권5호
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• pp.867-873
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• 2008

임상시험의 자료에 대하여 통계적 검정을 실시하는 경우 유의수준 5%를 사용하는 것이 관례이다. 하지만 동등성 시험을 신뢰구간을 사용하여 검정하는 경우, 신뢰도 90%인 신뢰구간이 사용되고 있다. 흔히 신뢰도 $1-{\alpha}$인 신뢰구간을 검정에 사용하는 경우, 그 검정법의 유의수준은 ${\alpha}$이다. 이 때문에 동등성 검정에서 신뢰도 90%인 신뢰구간을 사용하게 되면, 유의수준은 10%가 되는 것이 아닌가 하는 혼란을 일으켰다. 본 논문에서는 이와 관련된 이슈들을 관련 문헌의 검토와 시뮬레이션을 통하여 명확하게 하여, 제약회사, CRO, 대학병원 등에 종사하는 통계전문가들에게 도움을 주고자 한다.