계단식 단부 형태의 탄소섬유시트로 보강된 RC보의 구조거동 평가에 관한 실험적 연구

김영희,김희선,Kim, Young-Hee,Kim, Hee-Sun 한국복합신소재구조학회 2012 복합신소재구조학회논문집 Vol.3 No.4

This paper presents experimental studies aiming at evaluation of structural behaviors of RC (Reinforced Concrete) beams externally strengthened with taper ended CFRPs(Carbon Fiber Reinforced Polymers). Experiments are performed with RC beams having different numbers of CFRP layers and length of each layer. The beams are subjected to four point-bending with simply supported condition. Test results of taper ended CFRPs and non-tapered CFRPs are compared and the better strengthening effect is observed from tapered ended CFRPs.

휨 보강용 섬유시트연구동향소개

김영희,김희선,Kim, Young-Hee,Kim, Hee-Sun 한국복합신소재구조학회 2013 복합신소재학회논문집 Vol.4 No.1

Characterization of Salmonella Adhesins Required for Colonization of Animals

김영희,김상웅,강호영,Kim Young Hee,Kim Sam Woong,Kang Ho Young Korean Society of Life Science 2005 생명과학회지 Vol.15 No.2

Following ingestion, Salmonella must adhere to and colonize the intestinal epithelium of the host in order to establish infection. S. typhimurium synthesize several appendages that are believed to mediate attachment. These include type 1 fimbriae, plasmid-encoded (PE) fimbriae, long polar (LP) fimbriae, and thin aggregative fimbriae. However, the precise roles of these putative adhesins remain unclear, due to conflicting data in the literature. We constructed strains lacking four different fimbriae including type 1 fimbriae, PE fimbriae, LP fimbriae, and thin aggregative fimbriae, as well as strains lacking each fimbriae alone. In cell culture adhesion assays, these mutants adhered to several mammalian cell lines as well as wild-type S. typhimurium. These strains were also screened for virulence in mice, and all strains were virulent or nearly as virulent as their wild-type parents. In contrast, When a strain lacking four fimbriae was screened for virulence in chicks, it was found to be highly attenuated. This suggests a role for either type 1 fimbriae, PE fimbriae, LP fimbriae or thin aggregative fimbriae or a combination of thease fimbriae in the colonization of chicks. It also suggests that differences exist with respect to the surface structures that mediate attachment of Salmonella in chicks as compared with mice.

요가 프로그램이 재가노인의 우울, 삶의 질, 일상활동장애에 미치는 효과

김영희,박금숙,양경희,정헌영,양희정,Kim, Young-Hee,Park, Kum-Sook,Yang, Kyung-Hee,Jeong, Heon-Young,Yang, Hee-Jung 대한예방한의학회 2013 대한예방한의학회지 Vol.17 No.3

Objective : The purpose of this study was to investigate the effects of yoga program on depression, quality of life, and difficulty of daily activities in community elders. Methods : A Nonequivalent control group pretest-posttest design was used for this study. Elderly people who agreed to participated in the study were assigned to a experimental group(n=17) or a control group(n=17). The yoga program conducted 90minutes, 2times a week for 1 year. Study outcomes were measured by structured questionnaires from March, 2012 to Feb., 2013. For data analysis, Chi-square test, t-test, and Mann-Whitney U test were performed using SPSS version 17.0. Results : Depression was not significant difference between the two groups in pretest and posttest. But there was significant differences between the two groups in quality of life (t=3.984, p<.001), and difficulty of daily activities (t=-3.083, p=.004). Therefore, the experimental group showed significant improvement in quality of life and reduce difficulty of daily activities. Conclusion : The yoga program was effective in increasing quality of life and decreasing difficulty of daily activities in community elders. When developing exercise program to improve health in older adults, it is important to consider physical exercise plus general health management.

Effect of Growth Conditions in the Attachment of Salmonella typhimurium to the Host Cells

김영희,김상웅,강호영,Kim, Young-Hee,Kim, Sam-Woong,Kang, Ho-Young Korean Society of Life Science 2005 생명과학회지 Vol.15 No.4

An approximately 10-fold higher level of adherence of Salmonella typhimurium strain TML to Int-407 cells was observed with organisms grown in Luria broth or in high-iron containing medium than those grown in low-iron containing medium. Iron specifically enhanced adherence, while other cations such as calcium, cobalt, copper, potassium, magnesium and manganese did not. It was suggested that iron did not act as a passive ligand - probably it stimulated production of bacterial factors necessary for adherence. A similar pattern of iron modulation of adhesiveness was also seen in Salmonella mutants with single or different combinations of multiple mutations in genes encoding the mannose sensitive hemagglutinin (type 1 fimbriae), mannose resistant hemagglutinin and flagellum. The adhesiveness of an isogenic fur mutant was modulated by iron in a manner similar to the wild-type strain, suggesting that iron modulation of adherence is independent of the fur gene product.

고점도 지류 및 섬유 문화재의 점도 측정 개선 방법 연구

김영희,홍진영,조창욱,김수지,이정민,서민석,최경화,Kim, Young-Hee,Hong, Jin-Young,Jo, Chang-Wook,Kim, Soo Ji,Lee, Jeung-Min,Seo, Min Seok,Choi, Kyoung Hwa 국립문화재연구소 2013 保存科學硏究 Vol.34 No.-

Paper, textile and wood materials are mainly consisted of cellulose. Cellulose is high molecule and make up the strong crystalline structure by hydrogen bonds. In particular, the polymerization degree of cellulose are closely related to the strength of fiber, and the permanence. the useful life of fiber, also depends on the degradation of this substance. The viscosity of cellulose is considered to be an important indicator of fiber damage in high molecule polymers. The viscosity measurements with CED solution is used to measure the molecular weight and the degree of polymerization of cellulose. Cellulose viscosity of wood fibers is measured with TAPPI standard method T230. However, TAPPI standard method T230 is difficult to completely dissolving the cellulose of high molecular weight and large degree of polymerization, such as Korea traditional papers and fabrics made with mulberry, ramie, cotton fibers. In this study, The high viscosity of hanji and fabric was measured with TAPPI standard method T254. T254 method is that the cellulose specimen with the proper amount of weaker (0.167M CED) solution, and completely dissolved with the stronger (1.0M CED) solution. It was found that cellulose with high degree of polymerization was dissolved more easily in general CED method.

섬유 재질에 대한 천연 살충·살균제의 적용성 평가

김영희,홍진영,정미화,조창욱,김수지,이정민,최정은,Kim, Young-Hee,Hong, Jin-Young,Jung, Mi-Hwa,Jo, Chang-Wook,Kim, Soo-Ji,Lee, Jeung-Min,Choi, Jung-Eun 국립문화재연구소 2011 保存科學硏究 Vol.32 No.-

Wood vinegar and Asarum sieboldii Miquel were selected as candidate materials showed antimicrobial activity and insect repellent activity. These natural pesticides have its own color and these could cause color difference on fabric materials. In the present study, we investigated the color difference of undyed and dyed fabrics to evaluate negative effect of wood vinegar and A. sieboldii Miquel. Undyed and dyed fabrics were exposed to natural pesticides of various concentrations for six months in relative humidity 70% and temperature $28^{\circ}C$. After exposure of pesticides, color difference (${\Delta}E*$) were investigated at two weeks intervals for six months. As a results, dyed cotton, silk and undyed silk fabrics exposed wood vinegar were not nearly changed in their colors, but color of only undyed cotton fabric was clearly changed by wood vinegar. Especially color difference by wood vinegar on undyed cotton fabric was most distinct as the concentration increased. On the other hand, all of fabrics exposed A. sieboldii Miquel were not nearly changed in their colors for six months. Therefore, this study first suggests that wood vinegar and A. sieboldii Miquel as natural insecticides could be used to conserve for textile cultural properties from insects and microorganism, but wood vinegar couldn't use the high concentration on undyed cotton fabric.

Lactobacillus plantarumCLP-1이 돼지바이러스에 미치는 효과

이건희(Gun-Hee Lee),김영희(Young-Hee Kim),조현아(Hyeon-A Cho),강성기(Sung-Gi Kang),김동건(Dong-Gun Kim) 한국생물공학회 2011 KSBB Journal Vol.26 No.1

To isolate Lactic acid bacteria for animals, we have screened from Kim-chi, swine intestine, swine feces, and dairy products by random selection and anti-viral, antipathogenic bacteria test. Among them, CLP-1 shown that inhibitory effect against rotavirus, porcine epidemic diarrhea (PED) virus, Salmonella sp, and E.coli. By examining biological property, API-ZYM and identified Lactobacillus plantarum by 16S rDNAgene sequence. CLP-1 determined resistance to low pH and bile salt. Futhermore, the cell body of CLP-1 adhered to the intestinal epithelium tissue of swine and Caco-2 cell. CLP-1 was examined on cell immune system modulating activity in vitro. The whole cell and cell culture supernatant was increasing of interferon-β activity. And then, CLP-1 increased prevention effect by Salmonella enteritidis infection in SPF chickens. And we determined similar result in pigs.

속도의 초기간 추정을 사용한 Navier-Stokes방정식 풀이 기법

김영희,이성기,Kim, Young-Hee,Lee, Sung-Kee 한국정보과학회 2005 정보과학회논문지 : 시스템 및 이론 Vol.32 No.9

We propose a fast and accurate fluid solver of the Wavier-Stokes equations for the physics-based fluid simulations. Our method utilizes the solution of the Stokes equation as an initial guess for the velocity of the nonlinear term in the Wavier-Stokes equations. By guessing the initial velocity close to the exact solution of the given nonlinear differential equations, we can develop remarkably accurate and stable fluid solver. Our solver is based on the implicit scheme of finite difference methods, that makes it work well for large time steps. Since we employ the ADI method, our solver is also fast and has a uniform computation time. The experimental results show that our solver is excellent for fluids with high Reynolds numbers such as smoke and clouds. 본 논문은 물리적인 힘을 기반으로 유체의 흐름을 실시간으로 시뮬레이션하기 위하여 유체 의 흐름을 지배하는 Wavier-Stokes 방정식에 대한 빠르고 정확한 풀이 기법을 제안한다 본 논문에서는 Navier-Stokes 방정식에 있는 비선형 항의 속도에 대한 초기값을 Stokes 방정식의 해로써 추정한다. 주어진 비선형 미분방정식의 해에 근사하게 초기값을 추정함으로써 정확하고 안정적인 풀이 기법을 만들 수 있었다. 또한 유한차분법(finite difference method)의 암시적(implicit) 방법 중에서 방대한 계산량을 피할 수 있는 ADI(Alternating Direction Implicit) 방법을 사용함으로써 큰 시간 간격(time-step)에 대해서 시스템이 안정적이며 계산속도 또한 빠르다. 실험 결과들은 특히 연기, 구름과 같이 큰 레이놀드 수(Reynolds number)를 가지는 유체에 대해서 탁월한 성능을 보여주었다.

대식세포가 β-tricalcium Phosphate 뼈이식제의 생분해에 미치는 영향

김영희,변인선,오익현,민영기,양훈모,이병택,송호연,Kim, Young-Hee,Jyoti, Anirban,Byun, In-Sun,Oh, Ik-Hyun,Min, Young-Ki,Yang, Hun-Mo,Lee, Byong-Taek,Song, Ho-Yeon 한국세라믹학회 2008 한국세라믹학회지 Vol.45 No.10

Various calcium phosphate bioceramics are distinguished by their excellent biocompatibility and osteoconductivity. Especially, the exceptional biodegradability of $\beta$-TCP makes it a bone graft substitute of choice in many clinical applications. The activation of osteoclasts, differentiated from macrophage precursor cells, trigger a cell-mediated resorption mechanism that renders $\beta$-TCP biodegradable. Based on this evidence, we studied the biodegradation process of granular-type $\beta$-TCP bone graft substitute through in vitro and in vivo studies. Raw 264.7 cells treated with RANKL and M-CSF differentiated into osteoclasts with macrophage-like properties, as observed with TRAP stain. These osteoclasts were cultured with $\beta$-TCP nano powders synthesized by microwave-assisted process. We confirmed the phagocytosis of osteoclasts by observing $\beta$-TCP particles in their phagosomes via electron microscopy. No damage to the osteoclasts during phagocytosis was observed, nor did the $\beta$-TCP powders show any sign of cytotoxicity. We also observed the histological changes in subcutaneous tissues of rats implanted with granule-type $\beta$-TCP synthesized by fibrous monolithic process. The $\beta$-TCP bone graft substitute was well surrounded with fibrous tissue, and 4 months after implantation, 60% of its mass had been biodegraded. Also, histological findings via H&E stain showed a higher level of infiltration of lymphocytes as well as macrophages around the granule-type $\beta$-TCP. From the results, we have concluded that macrophages play an important role in the biodegradation process of $\beta$-TCP bone graft substitutes.