• Title/Summary/Keyword: Predominant period

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Changes in Benthic Polychaete Community after Fish Farm Relocation in the South Coast of Korea (어류양식장 이전 후 저서다모류 군집 변화)

  • Park, Sohyun;Kim, Sunyoung;Sim, Bo-Ram;Park, Se-jin;Kim, Hyung Chul;Yoon, Sang-Pil
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.27 no.7
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    • pp.943-953
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    • 2021
  • The purpose of this study is to investigate sediment recovery after the relocation of fish cage farms, by examining the changes in sediments and the benthic polychaete community. A preliminary survey was carried out in October 2017, before the relocation of the farms, and monthly surveys were conducted from November 2017 to October 2018 after the farms were moved. Subsequently, it was conducted every 2-3 months until October 2020. The survey was carried out at three stations (Farm1-3) at the location of the removed fish farms and at three control stations (Con1-3) without farms. The overall organic carbon content of the farm stations was higher than the control stations, but it gradually decreased after the farm was demolished, and there was no statistically significant difference about one year after the relocation of the farms (p<0.05). In the benthic polychaete community, abiotic community appeared at the farm stations in the summer, and consequently, the community transitioned to a low-diversity region with the predominant species Capitella capitata, which is an indicator of pollution. Until the abiotic period in the summer of the next year, the species diversity increased and the proportion of indicator species decreased, showing a tendency of recovering the benthic polychaete community, and these changes were repeated every year. In this study, the abiotic community appeared every year owing to the topographical characteristics, but as the survey progressed, the period of abiotic occurrence became shorter and the process of community recovery progressed expeditiously. Biological recovery of sediments after the relocation of the fish farms is still in progress, and it is imperative to study recovery trends through continuous monitoring.

Development and application of prediction model of hyperlipidemia using SVM and meta-learning algorithm (SVM과 meta-learning algorithm을 이용한 고지혈증 유병 예측모형 개발과 활용)

  • Lee, Seulki;Shin, Taeksoo
    • Journal of Intelligence and Information Systems
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    • v.24 no.2
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    • pp.111-124
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    • 2018
  • This study aims to develop a classification model for predicting the occurrence of hyperlipidemia, one of the chronic diseases. Prior studies applying data mining techniques for predicting disease can be classified into a model design study for predicting cardiovascular disease and a study comparing disease prediction research results. In the case of foreign literatures, studies predicting cardiovascular disease were predominant in predicting disease using data mining techniques. Although domestic studies were not much different from those of foreign countries, studies focusing on hypertension and diabetes were mainly conducted. Since hypertension and diabetes as well as chronic diseases, hyperlipidemia, are also of high importance, this study selected hyperlipidemia as the disease to be analyzed. We also developed a model for predicting hyperlipidemia using SVM and meta learning algorithms, which are already known to have excellent predictive power. In order to achieve the purpose of this study, we used data set from Korea Health Panel 2012. The Korean Health Panel produces basic data on the level of health expenditure, health level and health behavior, and has conducted an annual survey since 2008. In this study, 1,088 patients with hyperlipidemia were randomly selected from the hospitalized, outpatient, emergency, and chronic disease data of the Korean Health Panel in 2012, and 1,088 nonpatients were also randomly extracted. A total of 2,176 people were selected for the study. Three methods were used to select input variables for predicting hyperlipidemia. First, stepwise method was performed using logistic regression. Among the 17 variables, the categorical variables(except for length of smoking) are expressed as dummy variables, which are assumed to be separate variables on the basis of the reference group, and these variables were analyzed. Six variables (age, BMI, education level, marital status, smoking status, gender) excluding income level and smoking period were selected based on significance level 0.1. Second, C4.5 as a decision tree algorithm is used. The significant input variables were age, smoking status, and education level. Finally, C4.5 as a decision tree algorithm is used. In SVM, the input variables selected by genetic algorithms consisted of 6 variables such as age, marital status, education level, economic activity, smoking period, and physical activity status, and the input variables selected by genetic algorithms in artificial neural network consist of 3 variables such as age, marital status, and education level. Based on the selected parameters, we compared SVM, meta learning algorithm and other prediction models for hyperlipidemia patients, and compared the classification performances using TP rate and precision. The main results of the analysis are as follows. First, the accuracy of the SVM was 88.4% and the accuracy of the artificial neural network was 86.7%. Second, the accuracy of classification models using the selected input variables through stepwise method was slightly higher than that of classification models using the whole variables. Third, the precision of artificial neural network was higher than that of SVM when only three variables as input variables were selected by decision trees. As a result of classification models based on the input variables selected through the genetic algorithm, classification accuracy of SVM was 88.5% and that of artificial neural network was 87.9%. Finally, this study indicated that stacking as the meta learning algorithm proposed in this study, has the best performance when it uses the predicted outputs of SVM and MLP as input variables of SVM, which is a meta classifier. The purpose of this study was to predict hyperlipidemia, one of the representative chronic diseases. To do this, we used SVM and meta-learning algorithms, which is known to have high accuracy. As a result, the accuracy of classification of hyperlipidemia in the stacking as a meta learner was higher than other meta-learning algorithms. However, the predictive performance of the meta-learning algorithm proposed in this study is the same as that of SVM with the best performance (88.6%) among the single models. The limitations of this study are as follows. First, various variable selection methods were tried, but most variables used in the study were categorical dummy variables. In the case with a large number of categorical variables, the results may be different if continuous variables are used because the model can be better suited to categorical variables such as decision trees than general models such as neural networks. Despite these limitations, this study has significance in predicting hyperlipidemia with hybrid models such as met learning algorithms which have not been studied previously. It can be said that the result of improving the model accuracy by applying various variable selection techniques is meaningful. In addition, it is expected that our proposed model will be effective for the prevention and management of hyperlipidemia.

Variation in Lipid Composition during the Growing Period of the Prawn I. Comparative Studies on the Flesh Lipid Composition of the Wild and Cultured Prawn (보리새우 성장중의 지질성분 변화에 관한 연구 1. 천연 및 양식산 보리새우의 근육 지질성분의 비교)

  • Ha Bong-Seuk;MATSUNO Takao;KATSUYAMA Masaaki
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.18 no.4
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    • pp.297-308
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    • 1985
  • Differences in lipid composition including fatty acid, lipid class, sterol and especially carotenoid between fleshes of wild and cultured prawn, Penaeus japonicus, were studied. Total lipids were extracted from the flesh during the spawning period and fractionated into two lipid classes of polar and nonpolar lipids by silicic acid column chromatography. The fatty acid composition of each lipid classes, total lipid (TL), nonpolar lipid (NL) and polar lipid (PL) were analyzed by gas liquid chromatography. The sterol and carotenoid composition of total lipids were determined by using thin layer chromatography, gas liquid chromatography and column chromatography using MgO-celite 545 and silicic acid-celite 545 as an absorbent, and by UV spectrophotometry. Total lipid contents of both fleshes from the wild and cultured prawn were about $2.0\%$ on average, but the content of the unsaponifiable matters in the cultured prawn (about $16.2\%$ in total lipid) showed a little higher than that of the wild prawn (about $13.9\%$ in total lipid) and the ratio of NL to PL in total lipid was 1:1.7. In the fatty acid composition of TL, the contents of $Cl_{16:0}\;and\;C_{20:3}$ fatty acids were higher in wild prawn than in cultured prawn, while the contents of $Cl_{18:1}\;and\;C_{20:5}$ fatty acids in cultured prawn were higher than those in wild prawn. The cultured prawn contained higher amounts of monoenoic acids and lower amounts of polyenoic acids than the wild prawn. In the fatty acid composition of NL, the wild prawn showed higher levels in $Cl_{18:0}\;and\;C_{20:1}$ fatty acid contents than the cultured prawn, while the cultured prawn contained much amout of $Cl_{16:0}\;and\;C_{18:1}$ fatty acids. On the other hand, the fatty acid composition of PL showed that $Cl_{16:1}\;and\;C_{17:1}$ fatty acid were higher in the wild prawn than in the cultured prawn, but in $Cl_{16:0}\;and\;C_{18:1}$ fatty acids, the levels were reversed. Consequently, the cultured prawn contained higher amount of monoenoic acids, and similar amounts of saturated acids and polyenoic acids to the wild prawn in NL. And the cultured prawn contained lower amount of monoenoic acids, and similar amounts of saturated acids and polyenoic acids to the wild prawn in PL. In sterol composition of both the wild and cultured prawn, the predominant sterol was cholesterol with the proportion of $78.7{\sim}88.9\%$ to the total sterol. In addition to the cholesterol, the other minor sterols such as 24-methylene cholesterol and sitosterol were detected. Total carotenoid content in flesh of the wild prawn was relatively higher than that of the cultured prawn marking 70 mg/100g of lipid in wild prawn and 40 mg/100 g of lipid in cultured prawn, respectively. The main carotenoids of the both prawns were astaxanthin($54.1{\sim}60.8%$), phoenicoxanthin ($16.5{sim}22.9%$),${\bata}-carotene\;(20.0{\sim}22.0%)$.

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Analysis of Antigenic and Genetic Variability of G-protein of Respiratory Syncytial Virus Subgroup A Isolated in Korea over 8 Years(1990~1998) (국내에서 분리된 Respiratory Syncytial Virus A 아군의 항원성의 변이와 G-단백 mRNA의 RT-PCR 생산물의 제한효소 처리 및 염기 서열 결정을 통한 유전자 변이의 분석)

  • Choi, Eun Hwa;Park, Ki Ho;Lee, Hoan Jong
    • Pediatric Infection and Vaccine
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    • v.6 no.2
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    • pp.219-233
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    • 1999
  • Purpose : Respiratory syncytial virus(RSV) is the major cause of lower respiratory tract infection in infants and young children. This study was performed to analyze antigenic and genetic variation of G protein of subgroup A RSV. Methods : One hundred seventy-nine strains isolated at the Seoul National University Children's Hospital over 8 years-period from 1990 through 1998 were analysed for antigenic and genetic variability. Analysis was made by reactivity with monoclonal antibodies raised against RSV, and by restriction mapping and, for selected strains, nucleotide sequencing following amplification of full sequence of G gene by reverse transcription-polymerase chain reaction. Results : Restriction fragment analysis of the amplified G protein gene revealed 23 restriction patterns, 12 of which included more than 2 isolate, and the most frequent genetic type comprised 30% of the strains. Indirect immunofluorescent staining with monoclonal antibodies revealed 6 antigenic types with one predominant pattern accounting for 91% of the total strains. The most frequent antigenic type had 21 restriction patterns, and some viruses with same restiction pattern had different monoclonal antibody reaction pattern. Nucleotide sequence homology of subgroup A was 91~93% between reference(A2, Long) and Korean isolates, 93~99% among Korean isolates. Maximum-parsimony analysis demonstrated that Korean isolates were distinct from reference strains and subgroup A strains were clustered in 4 groups. Conclusion : The restriction analysis pattern of G protein gene identified greater diversity within subgroup A than was seen with the monoclonal analysis and a variety of antigenic and genetic types of RSV are circulating in Korea which are different from reference strains or strains isolated from other countries.

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A Study on Make-up Culture of Korea, China and Japan (한국.중국.일본 여성의 색조대장문화)

  • 박보영;황춘섭
    • Journal of the Korean Society of Costume
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    • v.39
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    • pp.217-237
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    • 1998
  • The present research is to study the make-up culture of Korea and its neighboring countries such as China and Japan during the period from the prehistoric age to the 19th cen-tury. The research was made by documents analysis. The results are summerised as follows : (1) A man has a basic instinct to beautify himself. There was not a significant difference between the make-up behavior of men and women in its primal stage. It was by the start of farming and the division of labor that made the make-up behavior as a feminine culture. The difference of sexual role caused the con-ceptual difference between manly beauty and womanly beauty. It was very natural for women to regard the make-up as the best way for showing their feminine beauty. In Korea, China and Japan, there were vari-ous kinds of primal actions such as tattooing, body-painting, and tooth make-up which were used in the purpose of body protection, incantation, ornament, and so on. Ass their ornamental purpose was becoming more important, these primal actions became the basis of the feminine make-up culture. Nowadays make-up, having mental and emo-tional function, is helpful to increasing self-satisfaction, promoting good personal relation-ship, and attracting attention from the other sex. It also has other functions of showing social status, wealth, age, sex, courage, power, and so on. (2) The representative make-up product used widely in the three countries was Boon (powder) which decides the overall color of face. The key point in the production of Boon was to increase its power of adsorption. The invention of Yunboon (power mixed with lead) solved this major problem of Boon. Yeonji which decides the color of cheek was the mixture of Boon and the powder of Honghwa (a kind of red-colored flower or tree). Mimook (eyebrow pencil) was developed to match up with the various and changing currencies of penciling eyebrows in each nation and times, Yeonji and Joosa (red sand) were used as Jinji (lip stick). The predominant color of Jinji was red. As miscellaneous methods of partial make-up, there were Kon-ji used in a wedding cer-emony in korea, Aek-hwang, Hwa-jeon, Sa-hong, and Myun-yup in China, and Chi-heuk, a peculial method of partial make-up in japan. (3) There were various factors which decided the characteristics of make-up culture usually reflects international atmosphere, the form of government, economic situation, re-ligious and social ideology, aesthetic sense, symbolizing meanings of colors, and so on. The up and down of an influentian country was one of the major factors which decided the characteristics of the make-up culture of its neighboring countries. When a country took a liberal form of government, it had diverse and splendid tendencies in its make-up culture. The better a nation's economic situation is, the more abandant and various its make-up culture is, and sometimes, the more eccentric and decadents it was. In the field of make-up production, the three countries had their own characteristics. But, as a whole, China was the leading nation who spread the culture and products of make-up to Korea and Japan. Though the Chinese make-up culture and products were usually spread to Japan through Korean, there was some evidence of direct exchanges between China and Japan through its dispatches of Kyun-Tang-Sa(Japanese delegation to the Tang Dynasty). While religion had a positive influence on the development of make-up culture by introducing new methods of make-up, Confucianism exercised strict control over the make-up cul-ture. The currencies in arts and changes of esthetic sense introduced new methods and booms to the make-up culture. Literature made people pay increasing attentions to the countenances of women and changed the standards of esthetic sense. We can find out that the social status of woman was also reflected in the make-up culture. As the social status of women became higher, the feminine make-up culture also developed more then ever. As mentioned above, the make-up cultures of the three countries reflected their social values, esthetic senses, and emotional feelings. Through their cultural exchanges, the three countries could develop various make-up products and methods.

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Clinical Spectra of Auto-amputated Polyps: Comparison of Juvenile Polyps and Meckel's Diverticula (자동절제 대장 용종의 임상 양상: 연소성 용종 및 멕켈 게실과의 비교)

  • Kim, Jae-Young;Park, Jae-Hong;Choi, Gwang-Hae;Choe, Byung-Ho
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.12 no.1
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    • pp.10-15
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    • 2009
  • Purpose: The manner of rectal bleeding of auto-amputated polyps (AP) is similar to juvenile polyps (JP) or Meckel's diverticula (MD). We conducted this study to characterize the clinical spectrum of AP. Methods: Fourteen patients were enrolled this study who were diagnosed AP due to painless rectal bleeding. The clinical data of AP was assessed and then compared with the clinical data of JP and MD retrospectively. Results: The prevalence of AP was 10.4% (14/135) and high in younger patients compared with that of JP (p=0.042 below 2 years). Whereas JP was more common in patients aged 2 to 5 years (p=0.005). Male was predominant in AP (p=0.008 AP vs JP). The manner of rectal bleeding in AP group was sudden and transient. There was no significant difference in time interval between onset of rectal bleeding and diagnosis between the 3 groups. However AP was diagnosed in 9 patients (64.3%) within 7 days after onset of rectal bleeding, but JP was diagnosed in 5 patients (4.1%) in the same period (p<0.001). All of AP were located in the rectum and the sigmoid colon. The mean hemoglobin was 11.3${\pm}$1.5 g/dL in AP, 11.8${\pm}$1.3 g/dL in JP, and 8.4${\pm}$1.2 g/dL in MD (p<0.001, only significant in MD). Conclusion: AP may be considered in male older than 1 year with transient and sudden onset or increase of painless rectal bleeding without drop of hemoglobin level.

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A Preliminary Epidemiologic Study on Korean Veterans Exposed to Herbicides in Vietnam War (파월국군장병의 고엽제 위해에 관한 예비적 역학조사)

  • Kim, Joung-Soon;Lee, Hyun-Sul;Lee, Hong-Bok;Lee, Won-Young;Park, Young-Joo;Kim, Sung-Soo
    • Journal of Preventive Medicine and Public Health
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    • v.27 no.4 s.48
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    • pp.711-734
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    • 1994
  • Among chemical agents in herbicides, dioxin (2, 3, 7, 8-tetrachloro dibenzo-$\rho$-dioxin : TCDD), a chemical contaminant in herbicides sprayed during the Vietnam War has been known to be the major agent causing toxic effects. Approximately 320,000 korean soldiers participated the Vietnam War from 1964 to 1974. Although the potential hazards of the herbicides among Korean veterans exposed were implicated, the problem had not been a public issue until 1991 when Korean veterans were informed U.S. companies, the herbicides manufacturer payed fund, from which a trust fund for New Zealand and Australian Class members were established in 1985. After a series of appeals and demonstration by the Korean Veterans demanding medical care and compensation for their serious health damages, a bill of medical care and compensation for herbicides victims was promulgated in March 1993 and become effective from May 1993, This study was carried out with two major objectives : the first to understand the health problems caused from the herbicides by reviewing literatures published, and the second to examine the nature and extent of health impacts among Korean veterans exposed and to develop valid study methods for the major study by interviewing and reviewing records on a part of veterans (638 persons) registered and completed medical examination in Seoul Veterans Administration Hospital from June to October 1993. The results obtained are as followings: 1. The literature review of 107 papers revealed that 1) Dioxin is teratogenic, carcinogenic and affects almost all organs including nervous, endocrine, and reproductive systems in animal experiments. 2) The diseases showing evidence of causal association were Hodgkin's disease, non-Hodgkin's disease, lung cancer, lymphoma, soft tissue sarcoma, chloroacne and polyneuropathy when judged on the basis of consistency in study results and biological plausibility. 2. Interview and medical record review study on 638 veterans, though limited validity owing to lack of control group, crude estimates of dioxin exposure levels (no biomarkers measurable), and uncertainty of diagnosis, showed that: 1) Most of the study subject's were in their 40's of age and had been dispatched to Vietnam during the period from $1965{\sim}1970$ around one year. 2) Most frequently complained symptoms in medical examination were motor weakness (32%), sensory abnormalities in extremities (23%), skin diseases (22%), and pain in extremities (20%) whereas in Interview they were more frequent in order of skin problem (44%), motor weakness (38%), sensory abnormalities and pain in extremities(17% and 19% each). Kappa indices on the same category of complaints between two sources of information were variable and relatively low. 3) On medical examination, only a part of the 638 subjects had initial impression (442 pts) and final diagnosis (218 pts) suggesting decision making on diagnosis appeared to be difficult even with all available modern medical technologies: in initial impression disorders from peripheral and central neuropathy were predominant whereas in final diagnosis various types of skin disorder were most frequent 4) When dose-response relationship between several conditions (from questionnaire) and arbitrary exposure scores were examined by CMH linear trend test, spontaneous abortion, sexual problems and health problem of offsprings showed statistically significant linear trends. However, pregnancy, accident and suicidal attempts did not show any relationship in this study capacity. 5) Among complaints, psychosis and neurosis (anxiety, phobia) in interview study, and memory disorder and psychosis in medical record study revealed linear trend. 6) Skin disorder was the only condition showing linear trend in initial impression and none in final diagnosis on medical examination. Even though objective to select out dioxin-related disease or group of diseases from this study was not achieved the research experiences provided firm basis for developing various methodological approaches. 3. From this preliminary study we concluded that a larger scale major epidemiologic study on health impacts of herbicides among Korean veterans exposed is not only Indispensible but also well designed study with more valid exposure information and diagnosis may be able to establish causal relationship between certain groups of diseases and exposure to the herbicides among Korean veterans.

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Human Lung Cancer Cell Xenografts Implanted under the Capsule of Kidney, Spleen and Liver (폐암 세포주를 사용한 신, 비장 및 간 피막하 분식법의 비교)

  • 김수현;김종인;이해영;조봉균;박성달;김송명
    • Journal of Chest Surgery
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    • v.36 no.10
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    • pp.711-720
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    • 2003
  • Bakground : Complete resection by the surgery has been selected as the treatment of choice in lung cancer patients, but in cases of recurrence after excision or inoperable cases, the importance of anticancer chemotherapy has been emphasized. If one can select a set of the sensitive chemotherapeutic agents before anticancer chemotherapy, it will give more favourable results. Subrenal capsular assay has been recognized as a useful in-vivo chemosensitivity test of thoracic and abdominal tumors and it can be done in a short time for a rapid interpretation of tumor responsiveness to anticancer chemotherapeutic drugs. It has been reported that various kinds of cancer cells can be implantable to the kidney, but so far there is no comparative study of xenogeneic cell implantation on liver, spleen and kidney. The author implanted the human lung cancer cells under the capsule of S.D rat's liver, spleen and kidney respectively and compared the pattern of growth and histology. Material and Method: After incubation of human lung cancer cell line (SW-900 G IV) in RPMI 1640 (Leibovitz L-15 medium) culture media, 3${\times}$3${\times}$3 mm size fibrin clots which contain 108 cancer cells were made. Thereafter the fibrin clots were implanted at subcapsule area of liver, spleen and kidney of S.D. female rat. For immune suppression, cyclosporin-A (80 mg/Kg) was injected subcutaneously daily from post-implantation first day to sixth day. The body weight was measured at pre and post implantation periods. The growth pattern and the size of tumor mass were observed and the pathologic examination and serum tumor marker tests were performed. Result: Body weight increased in both of control and experimental groups. Serum Cyfra 21-1 was not detected. Serum levels of CEA and NSE revealed no significant change. The SCC-Ag increased significantly in implanted group. The growth rate of human lung cancer cells which was implanted on spleen was higher than on liver or kidney. The surface area, thickness, and volume of tumor mass were predominant at spleen. The success rates of implantation were 80% on kidney, 76.7% on spleen and 43.3% on liver. Pathologic examination of implanted tumors showed characteristic findings according to different organs. Tumors that were implanted on kidney grew in a round shape, small and regular pattern. In the spleen, tumors grew well and microscopic neovascularization and tumor thrombi were also found, but the growth pattern was irregular representing frequent daughter mass. Human lung cancer cells that were implanted in the liver, invaded to the liver parenchyme, and had low success rate of implantation. Microscopically, coagulation necrosis and myxoid fibrous lesion were observed. Conclusion: The success rate of implantation was highest in the kidney. And the mass revealed regular growth that could be measured easily. The SCC-Ag was presented earlier than CEA or Cyfra21-1. The Cyfra21-1 was not detected at early time after implantation. The best model for tumor implantation experiment for chemosensitivity test was subrenal capsular analysis than liver and spleen and the useful serum tumor marker in early period of implantation was the SCC-Ag.

Impacts of Contaminated Water Outflow from the Lake Sihwa on the Meiobenthic Animals Living in the Coastal Zones of the Kyonggi Bay (시화호 오염수 방류에 따른 중형저서동물의 군집변동)

  • 김동성;이재학
    • Korean Journal of Environmental Biology
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    • v.18 no.2
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    • pp.279-290
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    • 2000
  • To alleviate the harmful effects from contamination, the Sihwa Lake waters have been regularly fluxed out into the ocean to mix and circulate with the oceanic waters, and then allowed to flow back into the lake. In the present study, eco-environmental impacts by the outflowing contaminated lake waters to the benthic communities of the coastal zones along Kyonggi Bay were examined at three separate areas. A total of 22 groups of meiobenthic animals were commonly found in the subtidal zones of the Bay. All groups of the meiobenthic animals on the 1st and 7th days after the outflow were remarkably reduced in numbers from the selected areas examined, as compared to those observed one day before the outflow. It was also found that the community structure of meiobenthos was changed drastically: At the station near the water gate, for example, where the immediate outflow of the lake water was encountered, the benthic harpacticoids, the group observed to be one of the predominant groups before the outflow, were found to have disappeared completely. For an area that was relatively far away from the water gate, the reduction rate of meiobenthos after the outflow events was slower and more gradual than the nearer sites. An area that is the farthest from the water gate, no reduction in any of the meiobenthos group was observed. The ratio between nematodes/copepods (N/C) was remarkably changed by the outflows at the station near the water gate: One day before the outflow, the ratio was 0.7 while the ratio was 19.0 at the station near the water gate. In contrast, at the stations relatively far from the water gate, the ratio decreased one day after the outflow event, but increasing trends were observed one week later. In the tidal flats, Station 1 exhibited the common observed regional values of the ratio whereas Station 2 showed a very high ratio of 191.3. The results suggested that the contaminated lake water outflows directly effect meiobenthos in a relatively short time period and thus the meiobenthos may be a good indicator animal group for examining the effect of pollution. [Lake Sihwa, contaminat water outflow, meiobenthic animals living]

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Changes in Acidity and Distributions of the Vancomycin-Resistant Lactic Acid Bacteria in the Kimchi Fermented at Different Temperatures (발효 온도에 따른 김치의 산도 변화와 Vancomycin 내성 젖산균의 분포)

  • 정의숙;김기환;신원철;송광영;윤성식
    • Microbiology and Biotechnology Letters
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    • v.32 no.3
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    • pp.249-255
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    • 2004
  • Chinese cabbage ('Baechu') Kimchi was fermented at the three different temperatures right after it was prepared. Samples were taken everyday for measuring bacterial populations, pH, and titratable acidity through the whole periods of fermentation up to 50 days. pH values and developed acidity were significantly affected by the fermenting temperatures of 4, 10, and $20^{\circ}C$, suggesting that different bacterial flora has been established by the temperatures exposed. The modified MRS agar containing vancomycin (300 $\mu$g/mL) was used for isolating the vancomycin-resistant LAB strains and 127 isolates were finally obtained. Of the LAB isolates, 13 isolates were subjected to the identification experiments based on the biochemical characteristics and the molecular-typing approach, an ITS-PCR, whether they belong to the genus Leuconostoc or not. The data obtained from API 50 CHL kit resulted that six isolates were identified as the members of Leuconostoc and six as Lactobacillus brevis strains except for a single isolate YKI 30-0401, which was not able to be identified because its biochemical traits were not matched to the database of API 50 CHL kit. It was noted that some isolates were distinct in a couple of some biochemical characteristics compared with those of the reference Leuconostoc species. To overcome the limitations experienced in the commercial identification products above, an ITS-PCR experiment was also conducted for the isolates, resulting that eight isolates belong to Leu. mesenteroides ssp. mesenteroides or dextranicum with a single band of 564 bp, and four to L. brevis strains. The ITS-PCR profiles clearly differentiated the closely-related LAB isolates for which same results were obtained by the biochemical method. This molecular approach, however, failed to produce the amplicons for the YKI 20-1003, leaving the strain unidentified. Judging from the identification data obtained in the Kimchi fermented at $4^{\circ}C$ or $10^{\circ}C$, Leuconostoc spp. including Leu. mesenteroides/dextranicum were likely predominant species in the earlier stage and L. brevis occurred at the high level through the whole period. By contrast, L. brevis, as one of the major flora, possibly lead the fermentation from the beginning in the Kimchi fermented at $20^{\circ}C$.}C$.