• 식물조직배양학회지
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• 제24권4호
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• pp.239-256
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• 1997

Plants belonging to the category of 2n apomixis or agamospermy form embryos and seeds without the processes of normal meiosis and syngamy. Seeds produced in this way have identical genotype of their maternal parent. Three different types of agamospermy are recognized: diplospory, apospory, and adventitious (adventive) embryony. $F_1$ hybrid cultivars cannot be used as seed sources in the next ($F_2$) generation because this generation would be extremely variable as a result of genetic segregation. Hybrid vigor is also reduced in the $F_2$ generation. Therefore, parental stocks for hybrid seed production need to be maintained and cross must be continuously repeated. Agamospermic 2n apomixis would make it possible to fix the genotype of a superior variety so that clonal seeds faithfully representing that genotype could be continuously and cheaply produced independent of pollination. That is, $F_1$ hybrid seeds could be produced for many generations without loss of vigor or genotype alteration. Production of apomictic $F_1$ hybrid seed would be simplified because line isolation would not be necessary to produce seed or to maintain parental lines, and the use of male-sterile lines could be avoided. Overall, apomixis would enable a significant reduction in hybrid seed production costs. Additionally, the production of clonal seed is not only important for seed propagated crops, but also for the propagation of heterozygous fruit trees and timbers. Clonal seed would help avoid costly and time-consuming vegetative propagating methods that are currently used to ensure the large-scale production of these plants. Apomixis is scattered throughout the plant kingdom, but few important agricultural crops possess this trait Therefore, most research to date has centered on introgressing the trait of apomixis into agricultural crops such as wheat, maize, and some forage grasses from wild distant relatives by traditional cross breeding. The classical breeding approach, however is slow and often impeded by many breeding barriers. These problems could be surmounted by taking mutagenesis or molecular approach. Arabidopsis thaliana is a tiny sexually reproducing plant and is convenient in constructing and screening in molecular researches. Male-sterile mutants of Arabidopsis are particularly suitable genetic background for mutagenesis and screening for apomictic mutants. Molecular approaches towards isolating the genes controlling the apomictic process are feasible. Direct isolation of genes conferring apomixis development would greatly facilitate the transfer of this trait to wide variety of crops. Such studies are now in progress.

• 한국물환경학회지
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• 제21권4호
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• pp.347-352
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• 2005

The isolated microorganisms, Pseudomonas stutzeri, Raoultella planticola (Klebsiella), Serratia fonticola from petroleum contaminated soil were enriched on benzene, toluene, ethylbenzene, o-xylene as carbon and energy sources, respectively. And the degradation characteristics of BTEX was observed in the mixed BTEX substrates. We found that the BTEX in mixed substrates were degraded more than 50% by three isolated microorganisms. Among three isolated microorganisms, the highest degradation rate was observed in Pseudomonas stutzeri, but the degradation rate was different according to microorganisms. In order to increase the degradation efficiency, we applied the co-culture of isolated three microorganisms. The mixture rate of pseudomonas stutzeri : Raoultella planticola (Klebsiella) : Serratia fonticola was follows ; 1:2:1, 1:1:2, and 2:1:1, respectively. In two co-culture of 1:2:1 and 1:1:2, degradation rate was lower than isolated microorganisms. However, degradation rate became higher than isolated microorganisms and the degradation rate of benzene, toluene, and ethylene was more than 95% in co-culture of 2:1:1. The degradation rate increased through the co-culture of isolated microorganisms, however, the growth rate decreased. This was resulted from the substrate competition between microorganisms. The co-culture of microorganisms is a effective method to increase the degradation efficiency of BTEX and the co-culture mixing rate is a important factor for determination of degradation efficiency.

• 환경위생공학
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• 제7권2호
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• pp.95-110
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• 1992

Much progress has been made in understanding the subcellular events of the human lung injuries after acute exposure to environmental air pollutants. Host of those events represent oxidative damages mediated by reactive oxygen species such as superoxide, hydrogen peroxide, and the hydroxy, free radical. Recently, nitric oxide (NO) was found to be endogenously produced by endothelial cells and cells of the reticulo-endothelial system as endothelialderived relaxation factor (EDRF) which is a vasoactive and neurotransmitter substance. Together with superoxide, NO can form another strong oxidant, peroxonitrite. The relative importance of exogenous sources of $N0/N0_2$ and endogenous production of NO by the EDRF producing enzymes in the oxidative stresses to the heman lung has to be elucidated. The exact events leading to chronic irreversible damage are still yet to be known. From chronic exposure to oxidant gases, progressive epithelial and interstitial damages develop. Type I epithelial cells become thicker and cover a smaller average alveolar surface area while thee II cells proliferate instead. Under acute damages, the extent of loss of the alveolar epithelial cell lining, especially type II cells appears to be a good predictor of the ensuing irreversible damage to alveolar compartment. Interstitial matrix undergo remodeling during chronic exposure with increased collagen fibers and interstitial fibroblasts. However, Inany of these changes can be reversed after cessation of exposure. Among chronic lung injuries, genetic damages and repair responses received particular attention in view of the known increased lung cancer risks from exposure to several air pollutants. Heavy metals from foundry emission, automobile traffics, and total suspended particulate, especially polycystic aromatic hydrocarbons have been positively linked with the development of lung cancer. Asbestos in another air pollutant with known risk of lung cancer and mesothelioma, but asbestos fibers are nonauthentic in most bioassays. Studies using the electron spin resonance spin trapping method show that the presence of iron in asbestos accelerates the production of the hydroxy, radical in vitro. Interactions of these reactive oxygen species with particular cellular components and disruption of cell defense mechanisms still await further studies to elucidate the carcinogenic potential of asbestos fibers of different size and chemical composition. The distribution of inhaled pollutants and the magnitude of their eventual effects on the respiratory tract are determined by pollutant-independent physical factors such as anatomy of the respiratory tract and level and pattern of breathing, as well as by pollutant-specific phyco-chemical factors such as the reactivity, solubility, and diffusivity of the foreign gas in mucus, blood and tissue. Many of these individual factors determining dose can be quantified in vitro. However, mathematical models based on these factors should be validated for its integrity by using data from intact human lungs.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 추계학술발표회
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• pp.44-52
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• 2002

Low temperature thermal desorption (LTTD) has become one of the cornerstone technologies used for the treatment of contaminated soils and sediments in the United States. LTTD technology was first used in the mid-1980s for soil treatment on sites managed under the Comprehensive Environmental Respones, Compensation and Liability Act (CERCLA) or Superfund. Implementation was facilitated by CERCLA regulations that require only that spplicable regulations shall be met thus avoiding the need for protracted and expensive permit applications for thermal treatment equipment. The initial equipment designs used typically came from technology transfer sources. Asphalt manufacturing plants were converted to direct-fired LTTD systems, and conventional calciners were adapted for use as indirect-fired LTTD systems. Other innovative designs included hot sand recycle technology (initially developed for synfuels production from tar sand and oil shale), recycle sweep gas, travelling belts and batch-charged vacuum chambers, among others. These systems were used to treat soil contaminated with total petroleum hydrocarbons (TPH), polycyclic aromatic hydrocarbons (PAHs), pesticides, polychlorinated biphenyls (PCBs) and dioxin with varying degrees of success. Ultimately, performance and cost considerations established the suite of systems that are used for LTTD soil treatment applications today. This paper briefly reviews the develpoment of LTTD systems and summarizes the design, performance and cost characteristics of the equipment in use today. Designs reviewed include continuous feed direct-fired and indirect-fired equipment, batch feed systems and in-situ equipment. Performance is compared in terms of before-and-after contaminant levels in the soil and permissible emissions levels in the stack gas vented to the atmosphere. The review of air emissions standards includes a review of regulations in the U.S. and the European Union (EU). Key cost centers for the mobilization and operation of LTTD equipment are identified and compared for the different types of LTTD systems in use today. A work chart is provided for the selection of the optmum LTTD system for site-specific applications. LTTD technology continues to be a cornerstone technology for soil treatment in the U.S. and elsewhere. Examples of leading-edge LTTD technologies developed in the U.S. that are now being delivered locally in global projects are described.

• 한국토양비료학회지
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• 제14권1호
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• pp.17-23
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• 1981

요소(尿素)와 병용(倂用)된 염화가리나 황산가리(黃酸加里)가 담수(湛水) 치원조건하(置元條件下)에서 암모니아의 휘산(揮散)에 주는 영향(影響)을 밝히기 위(爲)하여 pH가 낮은 (4.85) 산성식질답토양(酸性埴質畓土壤)과 pH가 높은(6.70) 간척지사질식양토(干拓地砂質埴壤土)를 공시(供試)하여 질내(窒內)에서 시험(試驗)한 결과(結果)는 다음과 같다. 1. 산성토양(酸性土壤)에 사용(使用)한 가리(加里)는 pH를 높이고 암모니아의 휘산(揮散)을 증가(增加)하였다. 2. pH가 높은 간척지염류토양에서는 가리(加里)의 시용(施用)으로 pH를 낮추고 암모니아의 휘산(揮散)을 줄이는데 그 효과는 황산가리(黃酸加里)가 염화가리보다 컸다. 3. 황산가리(黃酸加里)보다 염화가리를 시용(施用)한 토양(土壤)에서 암모니아의 휘산(揮散)이 많은 것 같다. 그러나 pH가 높은 간척지토양(干拓地土壤)에서는 염화가리의 이 효과가 높은 염농도에 덮여 버리는 것 같다. 4. 요소(尿素)는 토양(土壤)의 pH를 크게 높였다. 산성(酸性) 토양(土壤)에서는 황산가리(黃酸加里)가 염화가리보다 토양(土壤)의 pH를 더 높였으나 원래(原來)의 pH가 높은 간척지토양(干拓地土壤)에서는 반대(反對)로 황산가리(黃酸加里)가 염화가리보다 pH를 낮추었다. $SO_4$의 환원(還元)에 기인(基因)하는 것으로 생각된다.

• 한국토양비료학회지
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• 제6권3호
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• pp.179-183
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• 1973

수량저하(收量低下)를 가져오지 않고 벼짚의 단백질함량(蛋白質含量)을 증가(增加)시키는 질소추비(窒素追肥) 시험(試驗)을 IR667(수원(水原) 214)과 진흥(振興)을 사용(使用), 포장(圃場)에서 행(行)하고 벼짚의 사료가치(飼料價値)를 일반분석(一般分析)에 의(依)하여 비교검토(比較檢討)하였다. 1. 진흥(振興)보다 IR667은 조단백(粗蛋白), 조(粗)섬유 회분함량(灰分含量)이 높고 전탄수화물(全炭水化物)은 낮았으며 조지방(粗脂肪)은 큰 차이(差異)가 없었다. 2. 후기추비(後期追肥)로 질소시비량(窒素施肥量)이 증가(增加)할수록 조단백질(粗蛋白質)과 전탄수화물(全炭水化物)이 증가(增加)하나 조(粗)섬유 조지방(粗脂肪) 및 회분(灰分)은 감소(減少)하며 이러한 현상(現狀)은 IR667에서 뚜렷하였다. 3. 벼짚중 인산(燐酸) 함량(含量)은 질소시비량(窒素施肥量)의 증가(增加)에 따라 감소(減少)하는데 진흥(振興)에서 뚜렷하였다. 4. 질소시비량(窒素施肥量) 증가(增加)에 따라 현미중(玄米中) 단백질함량(蛋白質含量)이 크게 증가(增加)하며 Ca는 감소(減少)하는 경향(傾向)이었다. 5. 벼짚중 조단백질함량(粗蛋白質含量)의 전국평균치(全國平均値)는 4.06%로 혼합산야초(混合山野草)의 그것 (6.71%)보다 훨씬 낮으나 질소시비법(窒素施肥法) 개선(改善)으로 수량(收量)을 증가(增加)시키는 동시(同時) 산야초(山野草)를 증가(增加)시킬 수 있을 것으로 보였다.

• 한국축산식품학회지
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• 제37권6호
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• pp.940-947
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• 2017

Goat milk has a protein composition similar to that of breast milk and contains abundant nutrients, but its use in functional foods is rather limited in comparison to milk from other sources. The aim of this study was to prepare a goat A2 ${\beta}$-casein fraction with improved digestibility and hypoallergenic properties. We investigated the optimal conditions for the separation of A2 ${\beta}$-casein fraction from goat milk by pH adjustment to pH 4.4 and treating the casein suspension with calcium chloride (0.05 M for 1 h at $25^{\circ}C$). Selective reduction of ${\beta}$- lactoglobulin and ${\alpha}_s$-casein was confirmed using sodium dodecyl sulphate-polyacrylamide gel electrophoresis and reverse-phase high-performance liquid chromatography. The hypoallergenic property of A2 ${\beta}$-casein fraction was examined by measuring the release of histamine and tumor necrosis factor alpha from HMC-1 human mast cells exposed to different proteins, including A2 ${\beta}$-casein fraction. There was no significant difference in levels of both indicators between A2 ${\beta}$-casein treatment and the control (no protein treatment). The A2 ${\beta}$-casein fraction is abundant in essential amino acids, especially, branched-chain amino acids (leucine, valine, and isoleucine). The physicochemical properties of A2 ${\beta}$-casein fraction, including protein solubility and viscosity, are similar to those of bovine whole casein which is widely used as a protein source in various foods. Therefore, the goat A2 ${\beta}$-casein fraction may be useful as a food material with good digestibility and hypoallergenic properties for infants, the elderly, and people with metabolic disorders.

• 한국보건간호학회지
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• 제10권1호
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• pp.12-22
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• 1996

Currently. exchanges of industrial workers between countries are more active than ever. and the problem of AIDS in connection with the operation of preventive educational programs has reached a point where the issue cannot be limited to native people alone any more. Based on such judgement. this research has been carried out to provide basic study materials by grasping the latent factors representing the difference between countries in the levels of right knowledge. attitude and behavior with respect to AIDS maintained by workers who have grown in different social and cultural living background. During the period from Apr. 1. 1995 to Jun. 30. questionnaires. written both in Korean and English, were distributed to Korean and Malaysian employees working at certain Korean video manufacturers. and the results of replies. given by 80 workers who were analyzed through matched sampling· method where ages and sex matched by country. were used as the research materials. The gathered materials were analyzed through the SPSS package t-test. ANOVA. factor analysis and multiple stepwise regression methods. and the following results were obtained. 1. The 2 extracted latent factors could be named 'common. social' knowledge factor and 'in-depth. psychological' knowledge factor respectively. 2. The percentile points of 'external. social' knowledge factor. in the case of Korean workers. howed 90.0 at average. a figure 13.75 points higher than those of Malaysian workers. 76.25. On the other hand. the percentile points of the 'in-depth. psychological'knowledge factor showed 70.80 at average in the case of Korean workers. a figure 7.47 points lower than those of Malaysian workers. 78.33. Meanwhile. the difference in percentile points between the 2 latent factors was 8.54 at average. indicating that the points of 'in-depth. psychological' knowledge factor was lower than those of the 'external. social' knowledge factor. 3. As for Korean workers. the percentile points of the 'in-depth. psychological' knowledge factor showed higher points in office workers than in non-office workers. and such variables exhibited in the position of workers can explain the $7\%$ of the latent factor. The percentile points of the 'in-depth. psychological' knowledge factors. in the case of Malaysian workers. showed higher points in groups who had religion than in groups who did not. and higher points in groups who obtained information from newspapers than in groups who obtained from televisions or other sources; and with these 2 variables. $26\%$ of this latent factor can be explained. The results. of analysis described so far suggest that while Korean workers possessed general level of knowledge on AIDS. they had low level of practical knowledge as far as its depth is concerned. and that they had social prejudice on patients as well as on the AIDS infection route. In addition. because the overall knowledge level of Malaysian workers. is lower than that of Korean workers. it suggests that separate programs intended for Malaysian workers are required prior to executing integrated programs.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2001년도 봄 학술발표회 논문집
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• pp.167-174
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• 2001

Reflection method using ultrasonic source has been attempted to obtain the information about tunnel lining structures composed of lining, shotcrete, water barrier and voids at the back of lining. In this work, two different types of sources, i.e. single-pulse source and sweep source, can be used. Single-pulse source with short time duration has the frequency content whose amplitudes tend to be concentrated around the dominant frequency, whereas sweep source with long time duration denotes a flat distribution of relatively larger amplitude over a broad frequency band, although the peak to peak amplitude of single-pulse source wavelet is equivalent to that of sweep source one. In traditional seismic application, a single-pulse source(weight drop, dynamite) is typically used. However, to investigate the fine structure, as it is the case in the tunnel lining structure, the sweep wavelet can be also a desirable source waveform primarily due to the higher energy over a broad frequency band. For the investigation purposes of sweep source, a physical modeling is a useful tool, especially to study problems of wave propagation in the fine layered media. The main purpose of this work was using a physical modeling technique to explore the applicability of sweep source to the delineation of inner layer boundaries. To this end, a two-dimensional physical model analogous to the lining structure was built and a special ultrasonic sweep source was devised. The measurements were carried out in the sweep frequency range 10 ∼ 60 KHz, as peformed in the regular reflection survey(e.g. roll-along technique). The measured data were further rearranged with a proper software (cross-correlation). The resulting seismograms(raw data) showed quitely similar features to those from a single-pulse source, in which high frequency content of reflection events could be considerably emphasized, as expected. The data were further processed by using a regular data processing system "FOCUS" and the results(stack section) were well associated with the known model structure. In this context, it is worthy to note that in view of measuring condition the sweep source would be applied to benefit the penetration of high frequency energy into the media and to enhance the resolution of reflection events.

• 가정과삶의질연구
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• 제7권1호
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• pp.97-118
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• 1989

The purpose of this study is to clarify the definition of middle age, to compare the different perspectives about mid-life crisis, and to identify the variables that cause the mid-life crisis of men and women.. For this purpose reviewing literatures and emprical research were conducted. For the emprical research, Mid-life Crisis Scale, Mid-life Indentity Scale, Family Relation Scale. Health Scale and Religious Scale were developed. The Sample was selected form the men and women living in Seoul, whose age is from 40 to 59 , and whose last child is older than 13 years of age. Among 820 respondents 218 men and 442 women were finally selected as datum sources. The data were analyzed by the statistical method such as the factor analysis frequency distribution, percentile, ANOVA, Pearson's correlation and regression analysis. The main results were as follows; 1) Men and women experience mid-life crisis some extent. The mid-life crisis score for men is 33.60 and 35.0 for women. This implies women reveal significantly higher crisis than men. As for women's mid-life crisis. self-awaring age, education, income, husband's occupation, employment status of wife and occupational status of wife have a significant influence Expecially employment status of wife seemed to interact with sex, husband's occupation and educational level of wife. however status of child, family pattern, son's existence are not as important an influence on mid-life crisis. 3) Among the psychological variables, work identity and physical identity have the strong influence on the mid-life crisis of men and women, It implies that mid-life crisis si lower when one has higher work identity and physical identity. 4) Mid -life crisis of men and women is influenced significantly according to family relation variables and health variables. It reveals that the better one's family relations and health sate, the lower one's mid-life crisis is. However menopause and the years after menopause do not influence on the mid-life crisis of women. 5) Mid-life crisis of women differs significantly according to the kind of religion and religious activity. That is mid-life crisis of women is lower when she believes in Protestantism and Catholicism and participate in more religious activity. Mid-life crisis of men is not significantly influenced by religious variables. After all among the five categories of variables that related to mid-life crisis, psychological variables-especially work identity and physical identity are observed to have the strongest degree of significance.