• Title/Summary/Keyword: 열분석

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Bioaccumulation and Expressions of Stress Response Genes in Benthic Oligochaete Worm Tubifex tubifex to Exposure of Cadmium-spiked Sediment (카드뮴 (Cd) 노출 퇴적물에 따른 실지렁이 Tubifex tubifex의 체내 축적과 스트레스 반응 유전자 발현)

  • Ji-Hoon Kim;Won-Seok Kim;Kiyun Park;Ihn-Sil Kwak
    • Korean Journal of Ecology and Environment
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    • v.56 no.4
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    • pp.320-329
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    • 2023
  • Cadmium (Cd), a heavy metal found in the aquatic environment, accumulates in organisms through the food chain. In the study, we investigated the survival rates, measurement of body Cd levels, and expression analysis of the stress response genes (Heat shock protein 70: HSP70 and Heat shock protein 60: HSP60) and antioxidant enzyme Glutathione S-Transferases (GST) on benthic oligochaete worm Tubifex tubifex exposed three concentrations of Cd, to analyze the bioaccumulation and changes of stress gene expressions to exposure toxicity of the Cd-spiked sediment. Survival rates of T. tubifex exposed to the Cdspiked sediment were 93% at 0.4 mg kg-1 Cd, 96% at 1.87 mg kg-1 Cd, and 93% at 6.09 mg kg-1 Cd for 10 days. Cd concentration in the body of T. tubifex was higher than that in the sediment. After Cd exposures for 10 days, the body Cd levels were 18.4 mg kg-1, 13.06 mg kg-1, and 79.11 mg kg-1 at exposed three concentrations of Cd, respectively. Upregulation of HSP70 gene expression was observed at all concentrations of exposed Cd as a time-dependent manner, whereas transcriptional expression of the HSP60 gene increased as a timedependent manner in T. tubifex exposed to the relative high concentration (6.09 mg kg-1) of Cd. However, GST gene expression increased on day 1 at all concentrations after Cd exposures, and then downregulated until 10 days. These results indicate to ecotoxicological and molecular effects in benthic oligochaete worm T. tubifex to Cd-spiked sediment and provide the basic information for the utilization of environmental toxicity assessment using the T. tubifex as a aquatic pollution indicator species.

Satellite-Based Cabbage and Radish Yield Prediction Using Deep Learning in Kangwon-do (딥러닝을 활용한 위성영상 기반의 강원도 지역의 배추와 무 수확량 예측)

  • Hyebin Park;Yejin Lee;Seonyoung Park
    • Korean Journal of Remote Sensing
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    • v.39 no.5_3
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    • pp.1031-1042
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    • 2023
  • In this study, a deep learning model was developed to predict the yield of cabbage and radish, one of the five major supply and demand management vegetables, using satellite images of Landsat 8. To predict the yield of cabbage and radish in Gangwon-do from 2015 to 2020, satellite images from June to September, the growing period of cabbage and radish, were used. Normalized difference vegetation index, enhanced vegetation index, lead area index, and land surface temperature were employed in this study as input data for the yield model. Crop yields can be effectively predicted using satellite images because satellites collect continuous spatiotemporal data on the global environment. Based on the model developed previous study, a model designed for input data was proposed in this study. Using time series satellite images, convolutional neural network, a deep learning model, was used to predict crop yield. Landsat 8 provides images every 16 days, but it is difficult to acquire images especially in summer due to the influence of weather such as clouds. As a result, yield prediction was conducted by splitting June to July into one part and August to September into two. Yield prediction was performed using a machine learning approach and reference models , and modeling performance was compared. The model's performance and early predictability were assessed using year-by-year cross-validation and early prediction. The findings of this study could be applied as basic studies to predict the yield of field crops in Korea.

Estimation of Fractional Urban Tree Canopy Cover through Machine Learning Using Optical Satellite Images (기계학습을 이용한 광학 위성 영상 기반의 도시 내 수목 피복률 추정)

  • Sejeong Bae ;Bokyung Son ;Taejun Sung ;Yeonsu Lee ;Jungho Im ;Yoojin Kang
    • Korean Journal of Remote Sensing
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    • v.39 no.5_3
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    • pp.1009-1029
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    • 2023
  • Urban trees play a vital role in urban ecosystems,significantly reducing impervious surfaces and impacting carbon cycling within the city. Although previous research has demonstrated the efficacy of employing artificial intelligence in conjunction with airborne light detection and ranging (LiDAR) data to generate urban tree information, the availability and cost constraints associated with LiDAR data pose limitations. Consequently, this study employed freely accessible, high-resolution multispectral satellite imagery (i.e., Sentinel-2 data) to estimate fractional tree canopy cover (FTC) within the urban confines of Suwon, South Korea, employing machine learning techniques. This study leveraged a median composite image derived from a time series of Sentinel-2 images. In order to account for the diverse land cover found in urban areas, the model incorporated three types of input variables: average (mean) and standard deviation (std) values within a 30-meter grid from 10 m resolution of optical indices from Sentinel-2, and fractional coverage for distinct land cover classes within 30 m grids from the existing level 3 land cover map. Four schemes with different combinations of input variables were compared. Notably, when all three factors (i.e., mean, std, and fractional cover) were used to consider the variation of landcover in urban areas(Scheme 4, S4), the machine learning model exhibited improved performance compared to using only the mean of optical indices (Scheme 1). Of the various models proposed, the random forest (RF) model with S4 demonstrated the most remarkable performance, achieving R2 of 0.8196, and mean absolute error (MAE) of 0.0749, and a root mean squared error (RMSE) of 0.1022. The std variable exhibited the highest impact on model outputs within the heterogeneous land covers based on the variable importance analysis. This trained RF model with S4 was then applied to the entire Suwon region, consistently delivering robust results with an R2 of 0.8702, MAE of 0.0873, and RMSE of 0.1335. The FTC estimation method developed in this study is expected to offer advantages for application in various regions, providing fundamental data for a better understanding of carbon dynamics in urban ecosystems in the future.

Hydrochemistry, Isotopic Characteristics, and Formation Model Geothermal Waters in Dongrae, Busan, South Korea (부산 동래 온천수의 수리화학 및 동위원소 특성, 생성모델 연구)

  • Yujin Lee;Chanho Jeong;Yongcheon Lee
    • The Journal of Engineering Geology
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    • v.34 no.2
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    • pp.229-248
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    • 2024
  • This investigated the hydrogeochemical and isotopic characteristics of geothermal waters, groundwaters, and surface waters in Dongrae-gu, Busan, South Korea, in order to determine the origins of the salinity components in the geothermal waters, and their formation mechanisms and heat sources The geothermal waters are Na-Cl-type, distinct from surrounding groundwaters (Na-HCO3- and, Ca-HCO3- (SO4, Cl)-type) and surface waters (Ca-HCO3(SO4, Cl)-type). This indicates the geothermal waters formed at depth as compared with the groundwaters. δ18O and δD values of the geothermal waters are relatively depleted as compared with the groundwaters, due to altitude effects and deep circulation of the geothermal waters. Helium and neon isotope ratios (3 He/4He and, 4He/20Ne) of the geothermal waters plot on a single mixing line between mantle (3He = 3.76~4.01%) and crust (4He = 95.99~96.24 %), indirectly suggesting that the heat source is due to the decay of radioactive elements in rocks. The geothermal reservoir temperatures were calculated using the silica-enthalpy and Giggenbach models, yielding values of 82~130℃, and the depth of the geothermal reservoir is estimated to be 1.7~2.9 km below the surface. The correlation between Cl/Na and Cl/HCO3 for the Dongrae geothermal waters requires the input of salty water. The supply of saline composition is interpreted due to the dissolution of residual paleo-seawater.

Genesis and Characteristics of the Soil Clay Minerals Derived from Major Parent Rocks in Korea IV. Genesis and Distribution of the Soil Clay Minerals (한국(韓國)의 주요(主要) 모암(母岩)에서 발달(發達)된 토양점토광물(土壤粘土鑛物)의 특성(特性)과 생성학적(生成學的) 연구(硏究) IV. 토양점토광물(土壤粘土鑛物)의 분포(分布) 및 생성(生成))

  • Um, Myung-Ho;Lim, Hyung-Sik;Kim, Tai-Soon
    • Korean Journal of Soil Science and Fertilizer
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    • v.25 no.3
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    • pp.202-212
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    • 1992
  • This study reports on the genesis and mineralogical characteristics of the clay minerals in the soils derived from the five major parent rocks of granite, granite-gneiss, limestone, shale, and basalt in Korea. The investigation on the mineralogical aspects of primary and secondary minerals of the rocks and coarse fractions in the soils have been already reported. In this report, the identification of clay minerals in the soil clay fractions was done through the analyses of chemical, X-ray diffraction, and thermal methods. The studies showed clearly that much of the clay minerals was evolved by the weathering of primary minerals and some were further developed by the transformation of secondary minerals. Cation exchange capacity(CEC) of the clay fractions increased with higher amotunts of vermiculite, chlorite, and illite, however, decreased with higher hydroxy octahedral sheet within the interlayer spaces of vermiculite even if dominant clay with vermiculite. Feldspars in the granite and granite-gneiss might be completely transformed to kaolin mineral, Illite, chlolrite, and vermiculite formed by the alteration of micas, amphibole, augite, and primary chlorile seem to be subsequently transformed to the mixed layer minerals such as illite/vermiculite, illite/chlorite, and chlorite/vermiculite. These weathering products may be ultimately transformed into kaolin minerals. The smectite minerals in the clay fractions of the soils developed on the limestone are considerably present and they seem to be formed directly by the precipitation from high Mg solution and/or by the transformation of vermiculite from micas and chlorite in the parent materials. Abundant presence of illite in the soil clays developed on the shale is considered to have inherited from the fine particles and more resistant hydrous muscovite. The weathering sequences of the hydrous muscovite were as follows according to the degree of soil development ; hydrous muscovite ${\rightarrow}$ illite/vermiculite mixed layer(Inceptisols, Daegu series) and hydrous muscovite ${\rightarrow}$ illite/vermiculite mixed layer ${\rightarrow}$ vermiculite ${\rightarrow}$ kaolin mineral(Alfisols, Buyeo series). The plagioclase in the basalt might be mostly weathered to kaolin minerais. The augite in the basalt is likely to be transformed through progressive stage of weathering, augite ${\rightarrow}$ chlorite ${\rightarrow}$ chlorote/vermiculite mixed layer ${\rightarrow}$ vermiculite ${\rightarrow}$ kaolin. Another weathering sequence of augite could be expected, augite ${\rightarrow}$ chlorite ${\rightarrow}$ illite by the presence of illite and illite/vermiculite mixed layer in the clay fractions. Vermiculite and gibbsite were quantified from thermogravimetry(TG) and kaolin minerals, from both TG and differerential thermal analysis (DTA). Vermiculite in Jangseong series from the limestone was the dominant clay mineral of 21.7 percent and had a range in the order of 9.2 percent in Buyeo series to 5.4 percent in Daegu series from the shale. The rest soils ranged from 8.8 to 28.3 percent. Kaolin minerals were the dominant clay mineral of 32.7 percent in Asan series from the granite-gneiss and Gueom series of 32.0 percent from the basalt. The soils from the limestone ranged from 9.4 to 14.9 percent. The rest soils ranged from 8.9 to 28.6 percent. Gibbsite were 3.9 and 2.3 percent for Weoljeong and Chahang series from the granite, respectively. In Asan and Cheongsan series from the giranite-gneiss were 1.4 and 4.5 percent, respectively, and 3.6 percent in Jangpa series from the basalt.

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Sasang Herb medicine, IRCT (InfraRed Computer Thermography), Yakchim (Korean herb-acupuncture) remedy (체통환자(體痛患者)의 사상의학적(四象醫學的) 사초(四焦)와 이목구비(耳目口鼻)를 중심(中心)으로 한 체열(體熱) 분석(分析))

  • Kim, Su-Beom;Song, Il-Byung
    • Journal of Sasang Constitutional Medicine
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    • v.8 no.1
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    • pp.377-393
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    • 1996
  • Lumbago is the common disease in the human, many people have been sicked the Lumbago. As the traditional methods of Lumbago treatment, acupuncture, moxibustion, herb medicines have been applied to a patient, nowadays, new methods have been applied physical remedy, Yakchim (Korean herb acupuncture) remedy, Chuna remedy to. This report was collected 73 Lumbago patients by name, sex, age, motive, symptoms, X-ray, CT, MRI, lRCT, Sasang constitution type, Sasang herb medicine, Yakchim, Chuna, period of remedy, satisfaction of remedy, at the "WooRee Korean Medical Clinic" during 21 months from Sep. 14, 1994 to May 25, 1996. And this report was studied about the distribution of the Sasang constitution type, the Sasang herb medicine, the effect, the period. The results were as follows: 1. Lumbago patients were distributed like that; Taeum-ln (太陰人) 47 (66.3 %), Soyang-In 16 (21.9 %), Soum-In (13.7 %), Taeyang-In (太陽人) 0. This was different from distribution of Donguisuseibowon (東醫壽世保元), Taeum-In (太陰人) 50%, Soyang-In (少陽人) 30 %, Soum-In (少陰人) 20 %, Taeyang-In (太陽人) little, this report shows that the number of Taeum-In (太陰人) is more than that of Donguisuseibowon and the number of Soum-In is less than that of Donguisuseibowon. 2. The average satisfaction of remedy was 60.3 %, Taeum-In's satisfaction was 66.0 %, Soum-In's satisfaction was 56.3 %, Soyang-In's satisfaction was 60.0 %. 3. The effective herb medicines were as follows, Soyang-In used the Hyong Bang Ji Hwang Tang (荊防地黃湯), Yuk Mi Ji Hwang Tang (六味地黃樓), Soum-In used the Sib Yi Mi Goan Jung Tang (十二味寬中湯), Taeum-In used the Chung Sim Yon Ja Tang (淸心蓮子陽), Chung Pae Sa Gan Tang (淸師爾肝湯), Yeol Da Han So Tang (熱多寒少湯). 4. The period of remedy was about 6 weeks. The period of remedy of each types was as follows, Taeum-In was about 5.7 weeks, Soum-In was about 6.8 weeks, Soyang-In was about 4.2 weeks. 5. The method of Lumbago remedy is divided three types, sprain Lumbago, Pyobyong (表病 : outside Syndromes) Libyong (裡病 : inside symdromes). Soum-In's methods are Pyobyong's ascending the Yang (陽), adding the Gi (氣) [升陽益氣], and Libyong's descending the inside Yim (裡陰) [裡陰降氣], Soyang-In's methods are Pyobyongs's decending the outside-Yim [表陰降氣], and Libyong's ascending the cool Yang (濟陽) [淸陽上升]. Taeum-In's methods are Pyobyong's ascending the Lung's Yang (肺陽升氣), and Libyong's colding the dried hot liver (淸肝燥熱). Taeyang's methods are strong the liver and making Yim. (補r肝生陰) 6. There are two methods for using the YakChim (Korean herb-acupuncture) by Sasang constitution medicine, one is to select the Yakchim, the other is to choice the point for appling the Yakchim. The first, to select the Yakchim, the other is follows; Soum-In can select the bee Venom, Soyang-In can select the H.O. (Hong Whoa 紅花), Taeum-In can select the I (Hodo 胡挑), V, O.K. (Ungdarn, 薦膽), Uwhang 牛黃, Sa-Hyang 麝香, etc., Palgang Yakchim (eight principles Korean herb-acupuncture (八剛藥鐵)) could made by abstracted Sasang herb medicine. The second, to choice the points for applying the Yakchim are used in the TaeGiuk Acupuncture method (太梗針法), Sacho (四焦, four warmer) by Sasang constritutional physiology and pathology.

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A Proposal of a Keyword Extraction System for Detecting Social Issues (사회문제 해결형 기술수요 발굴을 위한 키워드 추출 시스템 제안)

  • Jeong, Dami;Kim, Jaeseok;Kim, Gi-Nam;Heo, Jong-Uk;On, Byung-Won;Kang, Mijung
    • Journal of Intelligence and Information Systems
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    • v.19 no.3
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    • pp.1-23
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    • 2013
  • To discover significant social issues such as unemployment, economy crisis, social welfare etc. that are urgent issues to be solved in a modern society, in the existing approach, researchers usually collect opinions from professional experts and scholars through either online or offline surveys. However, such a method does not seem to be effective from time to time. As usual, due to the problem of expense, a large number of survey replies are seldom gathered. In some cases, it is also hard to find out professional persons dealing with specific social issues. Thus, the sample set is often small and may have some bias. Furthermore, regarding a social issue, several experts may make totally different conclusions because each expert has his subjective point of view and different background. In this case, it is considerably hard to figure out what current social issues are and which social issues are really important. To surmount the shortcomings of the current approach, in this paper, we develop a prototype system that semi-automatically detects social issue keywords representing social issues and problems from about 1.3 million news articles issued by about 10 major domestic presses in Korea from June 2009 until July 2012. Our proposed system consists of (1) collecting and extracting texts from the collected news articles, (2) identifying only news articles related to social issues, (3) analyzing the lexical items of Korean sentences, (4) finding a set of topics regarding social keywords over time based on probabilistic topic modeling, (5) matching relevant paragraphs to a given topic, and (6) visualizing social keywords for easy understanding. In particular, we propose a novel matching algorithm relying on generative models. The goal of our proposed matching algorithm is to best match paragraphs to each topic. Technically, using a topic model such as Latent Dirichlet Allocation (LDA), we can obtain a set of topics, each of which has relevant terms and their probability values. In our problem, given a set of text documents (e.g., news articles), LDA shows a set of topic clusters, and then each topic cluster is labeled by human annotators, where each topic label stands for a social keyword. For example, suppose there is a topic (e.g., Topic1 = {(unemployment, 0.4), (layoff, 0.3), (business, 0.3)}) and then a human annotator labels "Unemployment Problem" on Topic1. In this example, it is non-trivial to understand what happened to the unemployment problem in our society. In other words, taking a look at only social keywords, we have no idea of the detailed events occurring in our society. To tackle this matter, we develop the matching algorithm that computes the probability value of a paragraph given a topic, relying on (i) topic terms and (ii) their probability values. For instance, given a set of text documents, we segment each text document to paragraphs. In the meantime, using LDA, we can extract a set of topics from the text documents. Based on our matching process, each paragraph is assigned to a topic, indicating that the paragraph best matches the topic. Finally, each topic has several best matched paragraphs. Furthermore, assuming there are a topic (e.g., Unemployment Problem) and the best matched paragraph (e.g., Up to 300 workers lost their jobs in XXX company at Seoul). In this case, we can grasp the detailed information of the social keyword such as "300 workers", "unemployment", "XXX company", and "Seoul". In addition, our system visualizes social keywords over time. Therefore, through our matching process and keyword visualization, most researchers will be able to detect social issues easily and quickly. Through this prototype system, we have detected various social issues appearing in our society and also showed effectiveness of our proposed methods according to our experimental results. Note that you can also use our proof-of-concept system in http://dslab.snu.ac.kr/demo.html.

Pain Complaint according to Usage of Standard-Sized Desks and Chairs for Middle and High School Students (중(中)·고등(高等) 학생(學生)들의 책상 및 의자(椅子)의 표준호식(標準號數) 사용여부(使用與否)와 통증(痛症) 호소율(呼訴率))

  • Kang, Kyung Yull;Cha, Byong Jun;Park, Jae Yong
    • Journal of the Korean Society of School Health
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    • v.8 no.2
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    • pp.219-232
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    • 1995
  • This study was conducted to examine both usage rate of standard sized desks and chairs for the middle and high school students and pain complant of students who use standard-size desk & chair in Taegu, Korea, by means of questionnaires with 1,201 students of both male and female middle and high schools in Taegu area from March 20 to April 19, 1995. The result of this study is summarized as follows. It was mostly shown that the desks and chairs used by those middle and high school students were 1-3 higher than their standard sizes, and that they also preferred a little higher size with respect to their desired sizes. The rate of students who use the standard size showed that the desk accounted for 30.5%, and chair for 21.0%, that the size bigger than the standard accounted for 61.3%, respectively, and 65.2, and that the size smaller than the standard accounted for 8.2%, respectively, and 13.8%. The using rate of the standard sized for the middle school students indicated that their desk accounted for 44.1%, and their chair for 26.0% which were higher than 16.1% and 14.7% for the high school students. Then, the rate of the male students indicated that their desk accounted for 31.5% and their chair for 24.5% which were higher than 29.6% and 17.6% of the female students. In addition, the using rate of the standard size for the public schools showed that the desk accounted for 34.2% and chair for 24.5% which were also higher than 27.1% and 17.5% of the private schools. It was shown, however, that the using rate of the standard size for both groups was lower. The most inconvenient factor in the usage of their desks appeared in such orders as their wear, narrow drawers, too low height and uneven face, while the factor in their chairs did in such orders as too hard chair body the surface and back part, wear, lower and higher height and narrow width. Their physical pains resulting from usage of those desks and chairs showed that the male and female middle school students' complaint rate of pains in their neck and shoulder accounted for 32.1%, respectively, and 36.0% which were highest, while those high school students' complaint rate in their waist accounted for 37.9%, respectively, and 44.1% which were hight. It was also shown that the bigger their height, the higher their complaint rate of pain in the waist, and that their complaint rate in the shoulder and neck was totally higher. When using the standard-sized desks and chairs, their complaint rate of pain in the shoulder and neck accounted for 25.4%, respectively, and 23.8%. As compared with them, when using the desks or chairs bigger than the standard size, their complaint rate accounted for 31.5%, respectively, and 31.8% which were high while it did 26.5% and 28.9% when using them smaller than the standard size which were also high, the usage of those standard-sized desks and chairs indicated lower complaint rate of pain in their waist than used the desks and chairs bigger or smaller than the standard size. The rate of the middle and high school students who use their standard size is very low and the size of their desks and chairs are quite different from those they hope to use and many students appeal their discomfort with their desks and chairs. Therefore, the school should try to provide the desks and chairs of the various students' standard sizes in consideration of their physical condition and it also should try to get extra desks and chairs of various sizes according to the students' standard size and their preference.

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Strain Improvement of the Genus Pleurotus by Protoplast Fusion (원형질체(原形質體) 융합(融合)에 의한 느타리버섯속(屬)의 품종개발(品種開發))

  • Yoo, Young-Bok;You, Chang-Hyun;Cha, Dong-Yeul
    • The Korean Journal of Mycology
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    • v.21 no.3
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    • pp.200-211
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    • 1993
  • Somatic hybrids of Pleurotus florida ASI 2016 and Pleurotus ostreatus ASI 2018 were obtained by protoplast fusion. The 40 fusants($P1{\sim}P40$) was examined for the yield on fermented and pasteurized rice straw in a tray. The carpophore yield of them were showed as the range of $27.0{\sim}155.2$, based on parental values of 100(ASI 2018), The pilei of fusants between orange white colored P. florida and dark grey colored P. ostreatus had mixed colors in the young stage. Other breeding programmes were performed to improve new varieties with high yield and good quality. A new oyster mushroom variety, Wonhyeongneutaribeosus(P72), was developed at the Agricultural Sciences Institute, Rural Development Administration in 1990. This P.florida-ostreatus-ostreatus hybrid P72 was selected from 38 protoplast fusion products($P41{\sim}P78$) between P.florida-ostreatus recombinant P5-M 43-arg rib and P. ostreatus ASI 2-13-0 2001-19-pro orn. The yield indexes of 38 hybrids ranged $40.5{\sim}152.7$ compared with the parental values of 100(ASI 2001). Hybrid P72 was characterized by the large fruiting bundle of semispherical shape with long stipe and by the small and circular pileus, resulting in lower harvesting cost. A significant increase in carpophore production was observed in somatic hybrids of protoplasts due to heterosis. A comparision of hybrid with parents P72 was made using isozyme analysis. The esterase banding patterns could be characterized by new bands in the hybrids. Seven fusion products of four crosses between P.florida ASI 2016 and P. ostreatus ASI 2018 were analysed with respect to the distribution of progenies and segregation of gene markers by random basidiospore analysis. Segregation of alleles should yield progeny of four genotypes in a Mendelian ratio of 1 : 1 : 1 : 1 for prototrophs, auxotrophs of one parental type, auxotrophs of the other parental type, and auxotrophic recombinants, respectively. However, five fusants of them did not detect one parental, P.ostreatus, type. Basidiospores could yield progeny of 16 genotypes in the cross of one of the recombinant P5-M43-arg $rib{\times}P. ostreatus$ ASI 2-13-pro orn but the segregants of three fusants were not detected clearly. The allele ratio of loci could be expected 1 : 1 : 1 : 1 for arg, rib, pro and orn. The ratio, however, would be changed to 4 : 1 : 1 : 1 with increasing proportion of argo In almost all the fusants, prototrophic recombinants were recovered in large numbers against auxotrophic markers. Parental genotypes were recovered with the recombinant progeny amounting to $38.68{\sim}99.56%$. The analysis provides proof of heterokaryosis and strong evidence for haploidy of vegetative nuclei, a sexual cycle consisting of nuclear fusion and meiosis.

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Processing of Intermediate Product(Krill Paste) Derived from Krill (크릴을 원료로 한 식품가공용 중간소재(크릴페이스트) 가공에 관한 연구)

  • LEE Eung-Ho;CHA Yong-Jun;OH Kwang-Soo;Koo Jae-Keun
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.18 no.3
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    • pp.195-205
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    • 1985
  • As a part of investigation to use the Anatrctic krill, Euphausia superba, more effectively as a food source, processing conditions, utilizations and storage stability of krill paste (intermediate product of krill) were examined and also chemical compositions of krill paste were analyzed. Frozen raw krill was chopped, agitated with $25\%$ of water to the minced krill and then centrifuged to separate the liquid fraction from the residue. This liquid fraction was heated at $98^{\circ}C$ for 20 min. to coagulate the proteins of krill, and it was filtered to separate the protein fraction. Krill paste was prepared with grinding the protein fraction, adding $0.2\%$ of polyphosphate and $0.3\%$ of sodium erythorbate to the krill paste for enhancing of functional properties and quality stability. The krill paste was packed in a carton box, and then stored at $-30^{\circ}C$. Chemical compositions of krill paste were as follows : moisture $78\%$, crude protein $12.9\%$, crude lipid $5.9\%$, and the contents of hazardous elements of krill paste as Hg 0.001 ppm, Cd 1.15 ppm, Zn 9.1 ppm, Pb 0.63 ppm and Cu 11.38ppm were safe for food. The amino acid compositions of krill paste showed relatively high amount of taurine, glutamic acid, aspartic acid, leucine, lysine and arginine, which occupied $55\%$ of total amino acid and also taurine, lysine, glycine, arginine and proline were occupied $65\%$ of total free amino acid. Fatty acid compositions of krill paste consist of $32.4\%$ of saturated fatty acid, $29.6\%$ of monoenoic acid and $38.0\%$ of polyenoic acid, and major fatty acids of product were eicosapentaenoic acid ($17.8\%$), oleic acid ($16.9\%$), palmitic acid ($15.3\%$), myristic acid ($8.7\%$) and docosahexaenoic acid ($8.4\%$). In case of procssing of fish sausage as one of experiment for krill paste use, Alaska pollack fish meat paste could be substituted with the krill paste up to $30\%$ without any significant defect in taste and texture of fish sausage, and the color of fish sausage could be maintained by the color of krill paste. Judging from the results of chemical and microbial experiments during frozen storage, the quality of krill paste could be preserved in good condition for 100 days at $-39^{\circ}C$.

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