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        검색결과 21

        2.
        2018.04 구독 인증기관·개인회원 무료
        The objectives of the present study were to examine the antioxidant activity of fractions with different isoelectric points from salmon enzymatic hydrolysates and obtain peptide fractions of sufficient amounts with higher antioxidant peptide fraction, which could be applied to the food and animal model systems. The salmon enzymatic hydrolysates were fractionated on the basis of the amphoteric nature of sample peptides by preparative isoelectric focusing without toxic solvents and reagents, which is termed autofocusing. Acidic and basic fractions showed higher 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity than the other fractions. The basic fractions showed higher hydroxyl (OH) radical scavenging activity. The weak acidic and weak basic fractions showed higher oxygen radical absorbance capacity (ORAC) values than the acidic and basic fractions. The acidic fraction showed higher metal chelating activity than other fractions. The acidic fraction suppressed lipid oxidation in the cooked patties to a greater extent than other fractions. These results suggest that peptides fractions from salmon enzymatic hydrolysate are effective antioxidant, and that autofocusing could be useful to increase antioxidant activity for application to food and animal model systems.
        4.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To obtain the immunomodulating polysaccharide from chaga mushroom (Inonotus obliquus sclerotia, IO), crude polysaccharide fractions (IO-M-CP and IO-CP, respectively) prepared from hot-water extract (IO-W) of I. obliquus by EtOH precipitation after MeOH reflux or not. After IO-W was re-dissolved in water followed by EtOH addition in the case without MeOH reflux, EtOH mixture was fractionated into EtOH-soluble (IO-E) and crude polysaccharide (IO-CP). In the meanwhile, MeOH-soluble fraction (IO-M) was separated from IO-W after MeOH reflux. The residue was dissolved in water and was added by EtOH, and then EtOH mixture was also fractionation into EtOH-soluble (IO-M-E) and crude polysaccharide (IO-M-CP). As a result of the macrophage stimulating activity of these fractions, IO-CP and IO-M-CP showed significantly increased cell proliferation and cytokines production than IO-W. Particularly, IO-M-CP promotes the production of IL-12 more than IO-CP. In the splenocytes proliferating activity and intestinal immune system modulating activity through Peyer’s patch, both of 2 crude polysaccharide fractions were significantly promoted in cell proliferation and cytokines production than IO-W, and IO-M-CP was more potent than IO-CP in IL-2 production from splenocytes and GM-CSF production (10 μg/mL) in Peyer’s patch cells. In addition, immunomodulating polysaccharide fractions (IO-M-CP and IO-CP) prepared from IO-W by EtOH precipitation with or without EtOH reflux showed no significant difference in the chemical composition and component sugar. These results suggested that MeOH reflux might exclude low-molecular weight materials from IO-W and consequently increase the immunomodulating activity of IO-M-CP. Therefore, it was confirmed that immunomodulation of polysaccharide prepared from hot-water extract of chaga mushroom was enhanced by fractionation including MeOH reflux and EtOH precipitation.
        4,000원
        6.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To understand size fractioned chlorophyll a and material cycles of coastal ecosystem in Uljin marine ranching area (JMRA) of East Sea, 4 times of survey were conducted from April to November 2008. Picoplankton, nanoplankton and netplankton in the surface of UMRA fluctuated with an annual mean of 0.26 μg L-1 between the lowest value of 0.03 μg L-1 and the highest value of 0.87 μg L-1, annual mean 1.32 μg L-1 between 0.11 μg L-1 and 5.60 μg L-1, annual mean 0.45 μg L-1 between no detected (nd) and 4.68 μg L-1, respectively. And the relative ratio of picoplankton, nanoplankton and netplanktons on the phytoplankton biomass was on annual average 12.9%, 65.0% and 22.1%, respectively. The 10 m layer was similar to the surface. The relative ratio of pico- and nano-plankton was higher throughout the year. That is, the material cycle of UMRA consists of a microbial food web rather than traditional food chain at a lower trophic levels. Primary production is deemed to have a higher possibility of being adjusted by top-down dynamics, such as micro-zooplankton grazing pressure rather than nutrients supply.
        4,000원
        7.
        2015.10 구독 인증기관·개인회원 무료
        Toxicity test of contaminate soil is very complex because of differential bioavailability in the soil. Therefore, bioavailability of metals in soil is a major factor influencing estimates of toxicity. In this study, the two major test was conducted. First, the toxicity of arsenic for the Collembola, Paronychiurus kimi, was assessed by determining the effects of increasing arsenic concentration on survival, reproduction and body concentration of As in five forested soils with different available phosphate and oxide-metal concentration. Second, the sequential extraction procedure (SEP) for arsenic by choosing extraction reagents commonly used for sequential extraction of metals was tested. The EC50 based on total As concentration in soil was estimated respectively. The available phosphate and oxide-metal concentration in soil influenced on As fraction in soil. Especially, As in soil which is non specifically and specifically sorbed (fraction 1, 2) has strong correlation with available phosphate and oxide-metal concentration (p<0.05). The toxicity is more higher in the soil with high available phosphate and low oxide-metal concentration. In addition, the high arsenic concentration in fraction which is amorphous and poor-crystalline hydrous oxide of Fe and Al (fraction 3) had effect to the toxicity. As a result, the toxicity of As is related with As concentration in fraction 1, 2 and 3 and the soil properties and the arsenic fractionation in soil have a influence on the bioavailability and toxicity.
        9.
        2014.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        물안정동위원소를 이용하여 지하수와 강우 또는 융설이 하천에 미치는 영향을 정량적으로 분리하는 방법을 동위원소 수문분리법이라고 하며 지난 30년 동안 사용되어 왔다. 오래된 물(지하수)과 새로운 물(강우 및 융설)의 두 성분이 하천에 영향을 미치는 것으로 가정하고 새로운 물과 오래된 물의 주어진 시간동안의 동위원소를 측정하여 각각의 성분에 대한 비율을 결정할 수 있다. 본 연구에서는 동위원소 수문분리법을 수계에 적용할 때 새로운 물의 시간적인 안정동위원소분화를 고려하지 않고 새로운 물의 평균값을 이용하였을 때 계통오차가 발생함을 보였다. 이러한 표준오차의 크기는 (1) 새로운 물이 하천에 많이 기여할수록, (2) 사용된 평균값과 분화된 새로운 물의 안정동위원소 값과 차이가 클수록, 마지막으로 (3) 오래된 물과 새로운 물의 안정동위원소 값의 차이가 작을수록 커진다. 집중 호우로 유출이 증가하거나 봄철에 지면이 아직 녹지 않아 융설이 유출이 되는 경우 새로운 물이 하천에 미치는 영향이 커지게 되어 상대오차 역시 증가한다. 이러한 오차를 줄이기 위해서 각각의 새로운 물, 오래된 물, 하천의 안정동위원소를 같은 시간 간격으로 측정하여 새로운 물이 분화되는 것을 고려한 수문분리법을 수행하는 것을 고려하여야 한다.
        4,000원
        10.
        2012.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 시험에서 건초(티머시, 알팔파 및 클라인)와 짚류(톨페스큐 및 볏짚)의 buffer 용해도와 단백질 분획이 실시되었으며, 조사료 자원의 buffer 추출이 in vitro 발효 성상, 분해율 및가스(CO2 및 CH4) 생성량에 미치는 효과를 조사하였다. 다른 조사료에 비해 총 단백질 중buffer 가용성 조단백질과 A fraction은 알팔파건초에서 각각 61% 및 41.77%로 가장 높았으며 볏짚에서 가장 낮았다(각각 42.8% 및19.78%). 총단백질 중 B1 fraction은 조사된 조사료간 비교적 큰 차이를 보이지 않았으나 B2fraction에서는 다른 조사료(6.34~8.85%)에 비하여 톨페스큐짚(10.05%) 및 클라인 건초(12.34)%에서 다소 높은 수준을 보였다. 총 단백질 중B3 fraction이 차지하는 비율은 톨페스큐짚에서38.49%로 가장 높았으나 다른 조사료 자원 간에는 큰 차이가 없었으며, C fraction의 경우 볏짚에서 가장 높은 비율(15.05%)을 보였다. 모든 사료에서 배양 개시 후 3시간(P<0.01) 및 6시간(P<0.05)에서 buffer 추출 전에 비해 추출후 배양액의 pH가 증가되었으며, 배양 6시간(P<0.05) 및 12시간(P<0.001)에서 다른 사료에비해 티모시 건초 및 알팔파 건초로부터의 pH가 낮았다. 배양액의 암모니아 농도는 모든 배양시간에서 가용성 물질의 추출 전 후에 다른조사료에 비해 알팔파 건초에서 가장 높았으나모든 사료의 추출효과는 배양 3시간(P<0.01)에서만 나타났다. 배양액의 총 VFA 농도는 배양24시간까지 알팔파 건초에서 가장 높았던 반면톨페스큐짚과 볏짚에서 가장 낮았다. 또한 모든 조사료에서 buffer 추출 전에 비하여 추출후에 총 VFA 농도가 감소되었다(P<0.01~P<0.001). Acetic acid (C2)의 조성 비율에서는 배양 6시간까지 추출 전에 더 높았으나(P<0.001)사료 간 차이는 없었다. Propionic acid (C3) 조성 비율 역시 배양 개시 후 3, 24 및 48시간(P<0.001)에 추출 전에 더 높았으며, 6 및 12시간의 배양액에서 대부분 건초(티모시, 알팔파 및 클라인)와 짚류(톨페스큐짚 및 볏짚) 간차이가 있는 것으로 조사되었다(P<0.05). 그러나 butyric acid (C4) 조성비율의 경우 대부분의배양시간에서 사료 간 차이는 없었다. 건물에서의 분해율 관련 parameter 중 a 값은 조사된전체 조사료에서 buffer 추출 전이 추출 후에비해서 높았으며(P<0.001), 다른 조사료에 비해톨페스큐짚과 볏짚에서 크게 낮았다(P<0.05).또한 b 값의 경우 역시 추출 전에 비해 추출후에서 현저히 낮았으나(P<0.001) 사료 간 차이는 없었다. 볏짚을 제외한 조사료에서 추출후에 비해 추출 전의 건물 유효분해율(EDDM)이 더 높았다(P<0.001). 조단백질에서의 a, b및 c 값은 추출 전에 비해 추출 후에서 현저히낮았으나(P<0.05) 사료 간 차이는 없었다. 조단백질 유효분해율(EDCP)에서는 다른 조사료 종류에 비해 톨페스큐짚과 볏짚에서 낮았다(P<0.05). 한편, NDF의 경우 a 값과 b 값(P<0.01)및 NDF 유효분해율(EDNDF, P<0.001)은 추출후에 비해 추출 전에 더 높았으나(P<0.01) 사료 간 차이는 보이지 않았다. 반추위미생물에의해 사료분해과정 중 생성되는 CO2 량도 24시간 배양까지는 추출 전에 더 많았으며(P<0.05~P<0.001), 톨페스큐짚과 볏짚에 비해 건초형태의 조사료로부터의 CO2 생성량이 더 많았다(P<0.05~P<0.01). 메탄가스(CH4) 생성량 역시 모든 배양시간에서 추출 전에 비해 추출 후에 크게 감소되었으며(P<0.01~P<0.001), 12~24시간을 제외하고는 짚류에 비해 건초에서 현저히 높은(P<0.05) 것으로 나타났다. 본 시험의 결과를 종합하면, 조사료 자원에 대한 buffer용해도와 단백질의 분획이 in vitro VFA 농도와 분해율 및 gas (CO2 및 CH4) 발생량 간 상호 밀접한 관계를 보이는 것으로 여겨진다. 이에 따라 조사료 이용 효율 개선을 위해 조사료자원에 대한 buffer 용해도와 단백질 분획을 반추동물 TMR 조제에 활용할 필요가 있는 것으로 여겨진다.
        4,900원
        11.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        It is known that the content of saturated fatty acids methyl ester (SFAME) affect the pour point of biodiesel at low temperature. In this study, biodiesel (BD) was produced from beef tallow (TAL) by alkali catalyst. To reduce the saturation in BD, acetone fractionation was applied. Besides, TAL was also solvent-fractionated to reduce the saturated fatty acid (SFA) content for further producing BD. With acetone, TAL or TAL methyl ester (5:1 v/w) were fractionated at 10, 0, -10, and -15℃, respectively. At -10℃, 17.35% of SFA was observed in fractionated TAL (liquid part, -10TAL) when 5:1 solvent ratio was used for 24 hr. Under the same condition, fractionated BD (liquid part, -10BD) showed SFA (33.14%) with 78wt % yield. Also, fractionation of BD with different concentration of crystallizer 209 (0.1, 0.5, and 1%) along with different time (2, 6, 12, and 24 hr.) was observed. The best condition for reducing the SFA was 0.5% of crystallizer 209 addition for 12 hr of fractionation time at -10℃, in which 30.14% of SFA content was observed in BD (liquid part). Among different crystallizer, ps 66 showed the least content of SFA content (23.28%) in BD after fractionation (-10℃ and 24 hr) with 0.5wt% addition.
        4,000원
        13.
        2006.04 구독 인증기관·개인회원 무료
        The primary aim pursued by the preparation of separation membrane is the preparation of the membrane thin as well as with no defect. The field-flow fractionation deposition is a new molding technology which can overcome the traditional disadvantages such as multi-preparation to the preparation of great area of separation membrane with no defect. Therefor the mainly ingredients which influence the appearance and performance of titanium membrane layer are investigated by scanning electricity mirror (SEM) as well as porous material testing instrument: powder performance prepared and confected; selection of supporting body; sintering system such as temperature and time. It is shown that the membrane thickness can be controlled at or so; the filtration precision mainly rests with powder performance and selection of supporting body and little sintering system
        15.
        1989.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In order to fractionate sardine oil by different solvents for an effective use of fish oil being subjected to the limit of use, an attempt was to investigate the proper solvents, ratios and fractionation time. The results of the study were as follows: 1. The proper solvent of fractionation using ethanol, isopropyl alcohol, acetone, and hexane was ethanol, and its optimum ratio was 2:1 (ethanol: oil, v/w). The proper time of ethanol fractionation by the ratio (2:1) was 4hr at 10℃, 6hr at 5℃, 8hr at 0℃and 8hr at -5℃, respectively. 2. In the fractionation by stages using the ratio (2:1) at each temperature, the yield of stearine was 8% at 10℃ (Fraction I), 32% at 5℃ (Fraction II), 7% at 0℃ (Fraction III) and 10% at 0℃ (Fraction IV), respectively. When ethanol fractionation was undertaken at 5℃ by stages, the yield of stearine (Fraction II) was high. 3. Iodine value of Fraction II was 96.8. This result indicated that the hydrogenation process would be simplified by fractionation. 4. The percentage of the decrease of polyenoic acids from original sardine oil to Fraction II oil was from 30.5% to 13.5%. The major fatty acids of Fraction II were palmitic and oleic acids and these fatty acids were about 52% of total fatty acids. Therefore, Fraction II, which remained liquid oil at room temperature because solid fat content was 6.9% at 20℃, would be used as frying oil.
        4,000원
        16.
        2016.11 서비스 종료(열람 제한)
        중금속에 의한 토양 오염이 국가적인 환경문제로 대두되면서 오염된 토양의 정화 기술 개발이 활발히 진행되고 있다. 최근 (구) 장항제련소의 중금속 오염부지에 대한 1차 정화사업이 완료되었고, 2차 사업이 진행되면서 토양세척기술이 가장 현실적인 중금속 오염 토양을 정화할 수 있는 기술로 인식되고 있다. 그러나, 토양세척공정은 75μm 미만의 미세토양에 대해서는 중금속의 화학적 추출이 거의 일어나지 않는다고 알려져 있어, 논토양과 같이 미세토 함량이 높은 부지에 대해서는 적용하더라도 그 효율이 낮아 폐기물로 버려지는 토양의 양이 많은 실정이다. 이에 본 연구에서는 미세토양에서 중금소의 추출 효율을 높이기 위해 중금속이 토양에서 어떠한 결합형태를 가지고 있는지와 중금속의 광물학적 특성을 고려하여 새로운 토양세척 공정을 제안하였다. 결합형태 분석을 통해 토양과 중금속의 결합강도에 대한 정보를 알 수 있으며, 기기분석을 통한 중금속의 광물학적 특성 분석을 통해 해당 중금속의 용해도에 대한 정보를 확인할 수 있다. 이 연구를 통해 제안된 공정을 비소, 납, 아연과 같은 중금속 오염 토양의 실험실 규모 정화에 적용하여 처리 효율 평가하였다. 비소의 경우 미세토만을 대상으로 실험한 결과 우려기준 이내로 정화할 수 있음을 확인하였다.
        18.
        2008.02 KCI 등재 서비스 종료(열람 제한)
        This study has been carried out to examine the feasibility of soil washing process for reducing arsenic contamination level of soil around Dalchên Mine. The results of physicochemical tests of the target soil showed that pH was weak alkalic (pH ~- 7.8), soil texture was coarse sand, and organic contents (5.7%) and CEC (Cation exchange capacity; 21.5 meq/100 g) were similar with those of soils generally found in Korea. Contamination levels of arsenic were found to over 201 mg/kg which exceed the Korea standard levels of countermeasure and concern. To investigate chemical partitioning of heavy metals, sequential extraction procedures were adopted and it was found that arsenic was predominantly associated with the residual fraction among five fractional forms as much as over 85%, which is demonstrating that only less than 15% of all might be vulnerable to a selected washing agents. Among 6 kinds of washing agents applied on the screening for arsenic-contaminated soil, HCl and H3PO4 solution were selected as promising washing agents. In comparison with HCl and H3PO4 solutions for arsenic washing by kinetic experiment in the change of pH, soil-solution ratio, temperature, and washing solution concentration, H3PO4 solution was determined to best one of agents tested, which showed faster washing rate than HCl to accomplish regulatory goal.
        20.
        1993.03 KCI 등재 서비스 종료(열람 제한)
        Concentrations of sulfate and δ-values of sulfate, (δ^34SO_4)_pw, dissolved in pore waters were measured from the sediment cores of the two different marine environments: deep northeast Pacific (ST-1) and coastal Kyunggi Bay of Yellow Sea (ST-2). Sulfate concentration in pore waters decreases with depth at both cores, reflecting sulfate reduction in the sediment columms. However, much higher gradient of pore water sulfate at ST-2 than ST-1 indicates more rapid sulfate reduction at ST-2 because of high sedimentation rate at the coastal area compared to the deep-sea. The measured 6-values, (δ^34SO_4)_pw, follow extremely well the predicted trend of the Rayleigh fractionation equation. The range of 26.7‰ to 61.3‰ at the coastal core ST-2 is not so great as that of 32.4‰ to 97.8‰ at the deep-sea core ST-1. Despite greater gradient of pore water sulfate at ST-2, the δ-values become lower than those of the deepsea core ST-1. This inverse relation between the S-values and the gradients of pore water sulfate could be explained by the combination of the two subsequent factors: the kinetic effect by which the residual pore water sulfate becomes progressively enriched with respect to the heavy isotope of ^34S as sulfate reduction proceeds, and the intrinsic formulation effect of the Rayleigh fractionation equation in which the greater becomes the fractionation factor, the more diminished values of (δ^34SO_4)_pw are predicted.
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