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첨가질량이 존재하는 변단면 4변고정 적층복합판으 진동해석
박제선,김경진,원치문,심도식 江原大學校 産業技術硏究所 1995 産業技術硏究 Vol.15 No.-
A method of calculating the natural frequency corresponding to the first mode of vibration of beams and tower structures, with irregular cross-sections and with arbitrary boundary conditions was developed and reported by D. H. Kim in 1974. This method has been developed for two-dimensional problems including the laminated composite plates and was proved to be very effective for the plates with arbitrary boundary conditions and irregular sections. In this paper, the result of application of this method to the clamped composite plates with non-uniform cross-section and with attached point mass/masses is presented.
반정량 식품섭취빈도조사지를 이용한 한국노인의 영양섭취 실태조사
이해정,박선주,김정희,김초일,장경자,임경숙,김경원,최혜미 대한지역사회영양학회 2003 대한지역사회영양학회지 Vol.8 No.3
The aim of this study was to assess the nutrient intakes of the elderly subjects in Korea. Dietary assessment was carried out using a semi-quantitative food frequency questionnaire (SQFFQ) developed by our laboratory, which included 98 commonly consumed food items selected from 1998 National Health and Nutritional Survey for Korean population. Subjects (n = 2,660) aged 50yr and over were recruited in Seoul, 6 metropolitan cities, and 8 mid-size cities. Calcium and riboflavin intakes of the elderly subjects aged 65 yr and over (n = 1,974) were much lower compared with Korean RDA. Nutrient intakes of the three age group (50 - 64 yr, 65 - 74 yr, 75 yr and over) were decreased as age increased in male and female elderly. Nutrient intakes of male elderly, 75 yr and over, were significantly decreased while in female elderly nutrient intakes were gradually decreased as age increased. Over 30% of the elderly subjects did not meet 75% RDA for calcium, iron, vitamin A, and riboflavin. The proportion of the elderly subjects whose intakes were below 75% RDA was much higher than the elderly whose intakes were above 125% RDA, especially among the elderly aged 75 yr and over. This study revealed that the Korean elderly had inadequate intakes for many nutrients. This will cause a serious nutritional problem for the elderly.
홍창우,김태경,김경진,김성환,김남윤,심도식,이정호,윤청호,백민경,원치문,박제선,이주형,정경일 강원대학교 석재복합신소재제품연구센터 1996 석재연 논문집 Vol.1 No.-
콘크리트 구조물이 대형화됨에 따라 설계단면이 증대되어 상대적으로 많은 경제적 손실을 부담하게 된다. 따라서 단면을 감소시키면서도 소요의 하중에 안전한 구조물을 건설하기 위해서는 우선적으로 구조물 건설에 기초가 되는 고품질, 고내구성의 고강도 콘크리트 개발이 절실히 요구된다 본 연구에서는 일정 시멘트비 및 혼화재 비율하에서 소요의 워커빌리티가 확보되는 고강도 콘크리트를 시간과 온도의 변화에 따라 증기 양생하여, 압축, 인장, 휨강도 뿐만 아니라 파괴특성을 실험적으로 연구하였다. 시료 제작시 시멘트 입자 사이의 공극 및 불연속 영역을 충전하여 고밀도화하기 위한 콘크리트용 혼화재로 시멘트 비표면적이 상당히 작은 초미립 분말인 실리카흄을 이용하였다. 또한 AE감수제 및 고성능 유동화제를 사용하여 혼화재의 첨가에 의하여 발생될 수 있는 워커빌리티의 감소를 방지하였다. 실험결과에 의하면 일정 양생 지속 시간하에서 온도의 증가에 따라 콘크리트의 압축, 인장 및 휨강도가 전반적으로 증가하였다. 동일하게 일정 온도하에서 양생 지속시간이 커짐에 따라 강도들이 증가됨을 알 수 있었다. 따라서 상대적으로 높은 온도와 긴 지속 양생 조건하에서 파괴에 대한 저항력이 크게 나타났다. The compressible, tensible, and flexibleresistance of the high strength concrete is analyzed by the experimentation in the present study. For the test, we cure several samples with the silica fume as a mixture being become dense the spaces between the particle of cement under the variation of both the temperature and the curing-interval. Then, the superplasticizer and the ezcon are also used to satisfy the required workability for construction. The compressible, tensible, and flexible resistances to a stress are increased as increasing the temperature and the time interval for the curing. Therefore it is concluded that the overal fractural and mechanical properties is improved by mixing the silica fume into the cement.
Protective Effect of Fucoidan Extract from Ecklonia cava on Hydrogen Peroxide-Induced Neurotoxicity
( Seon Kyeong Park ),( Jin Yong Kang ),( Jong Min Kim ),( Sang Hyun Park ),( Bong Seok Kwon ),( Gun-hee Kim ),( Ho Jin Heo ) 한국미생물생명공학회(구 한국산업미생물학회) 2018 Journal of microbiology and biotechnology Vol.28 No.1
We evaluated the antioxidant activity and neuronal cell-protective effect of fucoidan extract from Ecklonia cava (FEC) on hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>)-induced cytotoxicity in PC-12 and MCIXC cells to assess its protective effect against oxidative stress. Antioxidant activities were examined using the ABTS radical scavenging activity and malondialdehyde-inhibitory effect, and the results showed that FEC had significant antioxidant activity. Intracellular ROS contents and neuronal cell viability were investigated using the DCF-DA assay and MTT reduction assay. FEC also showed remarkable neuronal cell-protective effect compared with vitamin C as a positive control for both H<sub>2</sub>O<sub>2</sub>-treated PC-12 and MC-IXC cells. Based on the neuronal cellprotective effects, mitochondrial function was analyzed in PC-12 cells, and FEC significantly restored mitochondrial damage by increasing the mitochondrial membrane potential (Δψm) and ATP levels and regulating mitochondrial-mediated proteins (p-AMPK and BAX). Finally, the inhibitory effects against acetylcholinesterase (AChE), which is a critical hydrolyzing enzyme of the neurotransmitter acetylcholine in the cholinergic system, were investigated (IC<sub>50</sub> value = 1.3 mg/ml) and showed a mixed (competitive and noncompetitive) pattern of inhibition. Our findings suggest that FEC may be used as a potential material for alleviating oxidative stress-induced neuronal damage by regulating mitochondrial function and AChE inhibition.
Park, Kyeong Seon,Kwak, SooHeon,Cho, Young Min,Park, Kyong Soo,Jang, Hak C,Kim, Seong Yeon,Jung, Hye Seung John Wiley and Sons Inc. 2017 Journal of diabetes investigation Vol.8 No.2
<P><B>Abstract</B></P><P><B>Aims/Introduction</B></P><P>Dipeptidyl peptidase‐4 inhibitors might have pleiotropic protective effects on cardiovascular disease (CVD), in contrast to sulfonylureas. Therefore, we compared various CVD risk factors between vildagliptin and glimepiride.</P><P><B>Materials and Methods</B></P><P>We carried out a randomized, prospective and crossover trial. A total of 16 patients with type 2 diabetes whose glycated hemoglobin was >7% were randomized to add vildagliptin or glimepiride. After 12‐week treatment, each drug was replaced with the other for another 12 weeks. Before and after each treatment, glucose homeostasis and CVD risk factors were assessed, and the continuous glucose monitoring system was applied to calculate glycemic variability.</P><P><B>Results</B></P><P>The mean age of the participants was 60 years, 31% were men, body mass index 25.5 kg/m<SUP>2</SUP> and HbA1c 8.41%. Both vildagliptin and glimepiride significantly decreased glycated hemoglobin and glycemic variability indices. Despite the improved glucose homeostasis, favorable change of CVD markers was not prominent in both the arms, along with significant weight gain. Only plasma stromal cell‐derived factor (SDF)‐1α decreased by 30% in the vildagliptin arm. According to regression analyses, the reduction of SDF‐1α was independently associated with vildagliptin usage and serum interleukin‐6 changes, but white blood cells were not related with the SDF‐1α changes.</P><P><B>Conclusion</B></P><P>Compared with glimepiride, vildagliptin arrestingly decreased plasma SDF‐1α, and its clinical implications should be further investigated.</P>
Park Seon Kyeong,Kang Jin Yong,Kim Jong Min,Kim Min Ji,Lee Hyo Lim,Moon Jong Hyun,Jeong Hye Rin,Kim Hyun-Jin,허호진 한국미생물·생명공학회 2022 Journal of microbiology and biotechnology Vol.32 No.7
To confirm the therapeutic effect of the water extract from Ecklonia cava (WEE) against PM2.5 induced systemic health damage, we evaluated gut health with a focus on the microbiota and metabolites. Systemic damage in mice was induced through PM2.5 exposure for 12 weeks in a whole-body chamber. After exposure for 12 weeks, body weight and food intake decreased, and WEE at 200 mg/kg body weight (mpk) alleviated these metabolic efficiency changes. In addition, PM2.5 induced changes in the length of the colon and fecal water content. The administration of the WEE at 200 mpk oral dose effectively reduced changes in the colon caused by PM2.5 exposure. We also attempted to confirm whether the effect of the WEE is mediated via regulation of the microbiota-gut-brain axis in mice with PM2.5 induced systemic damage. We examined changes in the fecal microbiota and gut metabolites such as short-chain fatty acids (SCFAs) and kynurenine metabolites. In the PM2.5 exposed group, a decrease in the abundance of Lactobacillus (Family: Lactobacillaceae) and an increase in the abundance of Alistipes (Family: Rikenellaceae) were observed, and the administration of the WEE showed a beneficial effect on the gut microbiota. In addition, the WEE effectively increased the levels of SCFAs (acetate, propionate, and butyrate). Furthermore, kynurenic acid (KYNA), which is a critical neuroprotective metabolite in the gut-brain axis, was increased by the administration of the WEE. Our findings suggest that the WEE could be used as a potential therapeutic against PM2.5 induced health damage by regulating gut function.