In order to compare the suppressive effect of quercetin and several its glycosides, such as quercitrin (quercetin-3-rhamnoside), isoquercitrin (quercetin-3-gluooside), hyperin (quercetin-3-galactoside) and rutin (quercetin-3-rhamnosyl glucoside), on the genotoxicity by Nmethyl-N-nitrosourea(MNU), in vitro sister chromatid exchange(SCE) test using mouse spleen lymphocytes and in viuo micronucleus test using mouse peripheral blood were performed. MNU-indured SCEs in vitro were not decreased by the simultaneous treatment of teat compounds. Among them, quercetin and hyperin showed significant suppressive effects at high dose(10^(-5)M). On the other hand, MNU-induced micronucleated reticulocytes(MNRETs) in vivo were aignificantly decreased with good dose-dependent manner in all compounds tested. However, there were not significant differences between quercetin aglycone and its glycosides in the suppressive effects under experimental condition of this study. These results suggest that both of queroetin aglycone and its glycosides may act as an antigenotoxic agent in vivo and may be useful as a chemopreventive agent of alkylating agent.

YxFe2-xO3(x=0.82)의 결정상 변환을 상온에서의 x선회절과 온도구간 80-541K에서의 Mossbauer 분광 방법에 의해서 연구하였다. Xtjs 회절선은 시료가 orthorhombic 결정상과 garnet 결정상이 공존하고 있으며, 공존비는 실험오차 범위내에서 garnet 구조가 orthorhombic 구조보다 우세함을 보인다. 공존상중에서 garnet 구조의 자기상 변환온도는 536±5 K로 결정하였다. Debye 모형을 이용한 Mossbauer 스펙트럼의 recoil-free fration 분석결과는 garnet 결정상내의 d자리나 a자리에 vacancy의 존재 가능성을 시사한다. 부가적으로 시료가 포함하는 각 결정상의 Debye 특성온도를 결정하였다.

이 논문에서는 탄성-점탄성 복합재료의 공유면에 존재하는 계면균열에 대한 해석방법을 제시하고 있다. 먼저 탄성-점탄성 대응원리를 이용하여 탄성해석식으로부터 응력확대계수에 대한 식을 유도하였다. 다음으로 시간영역 경계요소법을 이용하여 균열선단에서의 응력을 계산한 다음 응력확대계수의 값을 구하였다. 수치해석의 결과는 본 논문의 정확성과 응용가능성을 보여준다.

이 논문에서는 경계요소법을 사용하여 횡방향의 인장변형률을 받는 단일방향 graphite/epoxy 복합재료의 섬유와 기지의 공유면에 존재하는 모서리 균열에 대한 응력확대계수를 계산하였다. 그러한 균열은 복합재료의 자유경계면에서 발생하는 특이 응력들에 의해 야기될 수 있다. 응력확대계수의 크기는 균열길이가 작은 경우에는 균열길이에 따라 조금씩 증가되다가, 균열길이가 커지면 일정한 값에 이르게 된다.

This paper intends to investigate commercial fish and shellfish 25 species (fish 8 species, shellfish 7 species, crustacean 3 species, molusc 4 species and echinodermata) for the distribution of sanitary indicator organisms (total viable counts, coliforms, staphylococci, vibrios, and enterococci) and diatributional change of indicator organisms according to storage temperature and period. The logarithmic mean of total viable counts for total commercial fish and shellfish 25 species was 5.41±0.26 CFU/g, and in accordance with fish and shellfishes, crustacean 6.76±0.67 CFU/g, shellfish 5.67±0.56 CFU/g, echinodermata 5.47±0.50 CFU/g, fish 5.021±0.38 CFU/g, and mollusc 5.03±0.65 CFU/g. The logarithmic mean of enterococci was 2.36±0.37 CFU/g, and in accordance with fish and shellfish, crustacean 3.44±0.12 CFU/g, shellfish 3.87±0.45 CFU/g, echinodermata 3.38±0.0 CFU/g, fish 2.16±0.41 CFU/g and mollusc 0.01±0.0 CFUIg. The logarithmic mean of vibrios was 1.60±0.59 CFUIg, and in accordance with fish and shellfish, crustacean 4.23±0.11 CFU/g, shellfish 3.58±0.90 CFUIg, echinodermata 1.64±0.34 CFU/g, fish 1.79±0.67 CFU/g and mollusc 1.07±0.61 CFU/g. The logarithmic mean of staphylococci was 1.60±0.59 CFU/g, and in accordance with fish and shellfish, shellfish 0.01±0.00 CFU/g, echinodermata 3.51±0.60 CFU/g, fish 1.68±0.64 CFU/g, crustacean 0.34±0.33 and mollusc 2.90±0.11 CFU/g. The logarithmic mean of coliforma was 2.2±0.32 CFU/g, and in accordance with fish and shellfish, echinodermata 3.58±0.89 CFU/g was highest, shellfish 3.25±0.30 CFU/g, crustacean 3.23±0.49 CFU/g, fish 2.18±0.63 CFU/g, peeled shellfish 1.80±0.51 CFU/ g and mollusc 1.55±0.95 CFU/g. As the results of research of the change of the contaminated indicator microflora in working with storage period at 10℃, 20℃ and 30℃, total viable counts was increased without storage temperature and enterococci were decreased slowly at 10℃, but increased at 20 and 30℃ Vibrios were decreased slowly at 10℃, decreased at 20℃ and 30℃ in 2 days after increased rapidly. Staphylococci were increased promptly without storage temperature in 2 days, then the total viable counts were maintained. Coliforms were increased at 10℃ by 7 days, then decreased or maintained after 14 days, changed at 20℃ in accordance with fish species in 2 days, then returned to the initial total viable count, and decreased rapidly at 30℃ on 2 days. By the way, there were no difference among the species.

The quality of silages, made from whole crop barley, rye, spring oat, Italian ryeglass, orchardgrass, alfalfa and grass-legume pasture mixtures, were evaluated under two different conservation techniques in baled silage making (BS) and conventional silage

Silage wm(cv, Gwanganok) was cultivated during 1991-1994 on paddy land as a rotational cropping system of rice, to evaluate the effect of cattle manure application on the soil characteristics, yield performance and quality of com plant. The treatments use

The main purpose of this study was to observe the effect of school lunch program on dietary habits of elementary school children and their food preferences. A questionnaire survey was conducted on 785 children and their mother in ele-mentary school with and without school lunch program. The results of this study can be summarized as follows: 1. 91.1% of subjects were eating rice for breakfast menu and 12.2% of subjects were skipping breakfast every morning. 2. Most of the children preferred fruits, ddugboggi, ice cream, fritter, cookie, bread, beverage and hot dog for snacks. 3. Despite of its restrictive practice, the school lunch program proved to be contributory to the improvement of children's food intake habits, table manners, keeping social order, sanitary consiousness, gratitude for their parents. 4. Children preferred kimbap, bokumbap and hamburger for main dish, fish jelly soup, brown seaweed soup and bean-sprout soup for soup, animal food for side dish and frying saute for cooking methods. 5. Most of the children disliked crown daisy, green pepper, mushroom, green onion, onion, dropwort, soybean and carrot for their food materials.

본연구에서는 n-type 세라믹 초전도체인 Nd2-xCexCuO4상의 산소함량에 따른 ?기적저항의 변화를 고찰하고자 하였다. 일반적인 소결과 어닐링과정을 결쳐 제조된 Nd1.85Ce0.15CuO4-x 시편을 여러 온도와 산소분압의 분위기하에서 어닐링시킴으로써 산소의 함유량이 다른 시편들을 준비하였고 각각의 시편의 산소함량은 TGA(Thermogravimetric Analysis0에 의해 측정하였다. Nd1.85Ce0.15CuO4-x시편의 전기적 저항 측정은 표준 4-탐침방법을 이용하여 액체헬륨을 주입시켜 상온으로부터 4K까지 측정하였다. Nd1.85Ce0.15CuO4-x시편의 산소함량, 3.96≤4-x≤4.0의 범위에서 전기적저항을 측정한 결과 초전도특성이 나타나기 시작한 임계산소함량은 4-x=3.990이었고 이때의 임계온도 Tc=12K이었다. 또한 임계온도, Tc는 산소함량 4-x=3.96에서 24K로 측정되었다. 특이할 만한 현상은 CuO/Cu2O 열역학적 상전이가 일어나는 조건이 Nd1.85Ce0.15CuO4-x 시편의 초전도가 일어나는 임계와 일치하였다. 즉, Cu2O가 안정한 영역에서는 초전도특성이 나타났고 CuO가 안정한 영역에서는 초전도특성이 나타나지 않았다.

2차원 유한요소 모델의 동일한 형상과 하중 조건에 있어서 6절점 요소의 굽힘 강성은 8절점 요소의 굽힘 강성보다 더 크게 나타난다. 이와 같은 현상은 3차원 16절점 요소와 20절점 요소에서도 나타나며, 완전 요소의 중간 절점들을 제거하므로 인하여 나타난다. 따라서 이 현상을 상대적 강성강화 현상이라 할 수 있다. 강성강화 현상을 보정하기 위한 매우 효과적인 방법으로 가우스 적분점 수정법을 도출하였으며, 이 방법은 확장적인 강성과 같이 다른 종류의 강성을 변화시키지 않으며, 또한 패취시험을 통과하였다. 적분점 수정량은 재료의 포아송비의 함수로 나타나며, 2차원 평면응력 상태와 평면변형율 상태에 대한 두개의 수정식을 구하였고, 또한 3차원 고체요소에 대하여 확장하였다. 가우스 적분점 수정법의 효과를 검증하기 위하여 보와 판의 자유 및 강제운동 문제를 해석하였으며, 등방성 적층 보와 판에 대해서도 단층보와 단층판과 같은 방법으로 적용하여 그 효율성을 입증하였다.

충의 방제에 효과적으로 이요할 수 있는 Bactllus thuringiensis 균주를 분리하기 위하여 전국의 다양한 토양을 채취하여 B. thuringiensis의 분포와 독성을 조사하였다. 총 548개의 토양을 전국 각지에 채취하여 포자와 내독소 단백질을 생산하는 64개의 B. thuringiensis를 분리했다. 분리된 64개의 B. thuringiensis를 나비목의 누에(Bombyx mori), 파리목의 빨간집모기(Culex pipens), 딱정벌레목의 쌀바구미(Sitophilus oryzae)의 세 종에 대해서 독성을 검정한 결과, 누에에 독성을 띠는 균주가 42.2%로 가장 많았으며, 누에와 빨간집모기에 동시에 독성을 띠는 균주가 31.3%, 빨간집모기에 독성을 띠는 균주는 20.3%의 비율로 분리되어 다양한 독성 분포를 보였다. 그러나 쌀바구미에 독성을 띠는 균주는 분리되지 않았고, 내독소 단백질은 형성하지만 독성이 없는 무독성 B. thuringiensis가 62%의 비율로 분리되었다.

Porcine follicular oocytes matured in culture were inseminated with frozen-thawed spermatozoa. When the oocytes were inseminated in the medium with oviductal epithelial cell monolayer, the penetration rates higher in those with (4.1, 31.7, 45.1, 54.5 and 69.4%) than without cells (0, 17.1, 34.8, 45.2 and 58.9%) at 4, 8, 12, 16 and 20 h after insemination. The proportions of polyspermy in penetrated oocytes in medium with or without cells increased with time of examine. In another experiment, the penetration rate was higher without (57.6%) than with (19.6~24.1%) preincubation of spermatozoa for 1~4 h in medium. However, when the oocytes were inseminated with spermatozoa preincubated for 1~2 h, the penetration rates significantly higher (P<0.05) in those with (65.6 and 55.9% for 1 and 2 h) than without (24.1 and 20.6% for 1 and 2 h) oviductal epithelial cell monolayer. On the other hand, the proportions of polyspermy decreased with time of spermatozoa preincubation. These results indicate the significant advantages of the spermatozoa preincubation with oviductal epithelial cell monolayer for 1 and 2 h to maintain penetration potential during in vitro fertilization in the porcine.

The experiments reported here take advantage of the large number of in vitro matured and in vitro fertilized(IVM /IVF) bovine oocytes which can be produced, permitting the design of controlled experiments to establish a simple defined medium for the study of early embryo requirements. A total of 1,386 IVM /IVF oocytes were used to compare a simple defined medium(KSOM) with more complex culture conditions used successfully for culture of bovine embryos but do not permit study of specific requirements. All experiments were extensively replicated factorials. In Experiment 1, KSOM was superior to Menezo B medium in producing morulae plus blastocysts from IVM /IVF oocytes(33 vs 20%, P<0.()5). The yield of morulae plus blastocysts with KSOM was 22% and with BRLC added was 30%. In Experiment 2, (a 2x2 factorial of KSOM with or without BRLC and 0, 1 ng /ml of platelet derived growth factor, PDGF) more morulae plus blastocysts (40%) were produced in KSOM-BRLC co-culture containing 1 ng /ml PDGF than in the control KSOM(12%). In Experiment 3, there was no dose response when 0, 1 and 5 ng /ml of PDGF were added. The results with simple defined KSOM medium are sufficiently promising to indicate that specific requirements of the embryo may be examined in future studies with KSOM as a base.