• 환경위생공학
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• 제22권4호
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• pp.23-32
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• 2007

Changes in the characteristics of dissolved organic matter was studied at selected stations in the Nakdong river basin using physical and chemical methods. Characteristics of dissolved organic matters were analysed and assessed. Production of disinfection byproducts were also investigated. Distribution of the organic compounds according to the Molecular weight(MW) indicate that MWs higher than 100K were highest with cattle excrement wastewater and MW between 100-10K were highest with waters from forest streams. Low MW compounds (Jess than 1K) were highest with the effluents from environmental facilities. Results of resin fractionation study show that acidic hydrophobic substances(AHS) were dominant in many stations. The values were higher in the samples from mainstreams and sidestreams where the influence of organic matter is higher than the water from environmental facilities. Hydrophilic neutral substances(HoN) such as hydrocarbon, pesticides and detergents were higher in the wastewater treatment facilities. HoN values of water from the forest streams were 4.7% indicating there is no synthetic pollutant.

• Food Science and Biotechnology
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• 제16권6호
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• pp.902-909
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• 2007

Granular maize starch was treated with Thermus scotoductus 4-${\alpha}$-glucanotransferase (${\alpha}$-GTase), and its physicochemical properties were determined. The gelatinization and pasting temperatures of ${\alpha}$-GTase-modified starch were decreased by higher enzyme concentrations. ${\alpha}$-GTase treatment lowered the peak, setback, and [mal viscosity of the starch. At a higher level of enzyme treatment, the melting peak of the amylose-lipid complex was undetectable on the DSC thermogram. Also, ${\alpha}$-GTase-modified starch showed a slower retrogradation rate. The enzyme treatment changed the dynamic rheological properties of the starch, leading to decreases in its elastic (G') and viscous (G") moduli. ${\alpha}$-GTase-modified starch showed more liquid-like characteristics, whereas normal maize starch was more elastic and solid-like. Gel permeation chromatography of modified starch showed that amylose was degraded, and a low molecular-weight fraction with $M_w$ of $1.1{\times}10^5$ was produced. Branch chain-length (BCL) distribution of modified starch showed increases in BCL (DP>20), which could result from the glucans degraded from amylose molecules transferred to the branch chains of amylopectin by inter-/intra-molecular transglycosylation of ${\alpha}$-GTase. These new physicochemical functionalities of the modified starch produced by ${\alpha}$-GTase treatment are applicable to starch-based products in various industries.

• 공업화학
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• 제3권2호
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• pp.318-326
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• 1992

분자량 350~360을 가진 비스페놀형 에폭시 수지(DER 331)를 전체 에폭시 성분 중 50% 이내의 범위에서 분자량 1,000~1,600을 가진 비스페놀형 에폭시수지(DER 662, 664) 및 분자량 800~1,000을 가진 노블락형 에폭시수지(DEN 439)와 혼합 사용하여 합성한 비닐에스테르수지의 액상 및 경화물성을 연구하였다. 희석점도는 분자량과 용해성의 영향을 받았으며 저분자량의 함량이 늘어날수록 낮아졌다. 경화시간은 MAA의 양에 영향을 받았으며 저분자량의 함량이 늘어날수록 비스페놀형은 빨라졌고 노블락형은 변화를 보이지 않았다. 경도와 신율은 분자구조의 영향을 받았으며 저분자량의 함량이 늘어날수록 떨어졌다. 굴곡강도와 인장강도는 DER 331 함량 30~40%에서 가장 우수했다.

• 폴리머
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• 제35권4호
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• pp.325-331
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• 2011

침투 가능한 수형 모델 유체의 방정식을 고찰하는 다양한 범위의 입자 충전 분을 ${\phi}$ 및 척력적 에너지 상수 ${\varepsilon}^*$에 대하여 분자 동력학 방법을 이용한 전산 모사를 수행하였다. 전산 모사로부터 얻어진 결과는 문헌에 보고된 고침투 근사식 및 저침투 근사식으로 알려진 두 가지의 한계적 이론식들과 직접 비교하였다. 낮은 척력적 에너지를 갖는 ${\varepsilon}^*$ <3.0의 경우 전산 모사 결과는 이들 두 이론식들과 일치하였으나, 반면 입자간 상호 포텐셜 에너지가 입자 자체 평균 운동 에너지의 두 배 이상 높은 척력적 에너지를 갖는 ${\varepsilon}^*{\geqq}3.0$의 경우 이들 이론식들 모두 전산 모사 결과를 재현하지 못하였다. 이는 특히 높은 입자 밀도와 높은 척력적 에너지를 갖는 ${\phi}{\geqq}0.7$ 및 ${\varepsilon}^*$=6.0의 경우 입자들의 클라스터 형성 및 자체 입자 배제 부피에 따른 비연속적 크기 효과에 기인되었다.

• Parasites, Hosts and Diseases
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• 제61권4호
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• pp.405-417
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• 2023

Chagas disease, caused by Trypanosoma cruzi parasite, is a significant but neglected tropical public health issue in Latin America due to the diversity of its genotypes and pathogenic profiles. This complexity is compounded by the adverse effects of current treatments, underscoring the need for new therapeutic options that employ medicinal plant extracts without negative side effects. Our research aimed to evaluate the trypanocidal activity of Bidens pilosa fractions against epimastigote and trypomastigote stages of T. cruzi, specifically targeting the Brener and Nuevo León strains-the latter isolated from Triatoma gerstaeckeri in General Terán, Nuevo León, México. We processed the plant's aerial parts (stems, leaves, and flowers) to obtain a methanolic extract (Bp-mOH) and fractions with varying solvent polarities. These preparations inhibited more than 90% of growth at concentrations as low as 800 ㎍/ml for both parasite stages. The median lethal concentration (LC₅₀) values for the Bp-mOH extract and its fractions were below 500 ㎍/ml. Tests for cytotoxicity using Artemia salina and Vero cells and hemolytic activity assays for the extract and its fractions yielded negative results. The methanol fraction (BPFC3MOH1) exhibited superior inhibitory activity. Its functional groups, identified as phenols, enols, alkaloids, carbohydrates, and proteins, include compounds such as 2-hydroxy-3-methylbenzaldehyde (50.9%), pentadecyl prop-2-enoate (22.1%), and linalool (15.4%). Eight compounds were identified, with a match confirmed by the National Institute of Standards and Technology (NIST-MS) software through mass spectrometry analysis.

• 한국환경농학회지
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• 제11권1호
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• pp.67-76
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• 1992

카드뮴내성균인 Pseudomonas Putida C1의 세포 내 카드뮴 축적기작을 구명하기 위하여 균체내 축적된 카드뮴의 세포 구성성분별 분포도, 단백질 함량변화 및 세포구성물질의 변화를 조사한 결과, 세포내에 축적된 카드뮴의 약 57%는 cell wall에 분포되어 있었으며 약 43%는 cytoplasm에 분포되어 있었다. Cytoplasm에 축적된 카드뮴은 protein과 nucleic acid 두 성분 모두에 분포되어 있었으며, cell wall에 축적된 카드뮴의 약 84% 이상이 polyphosphate-polysaccharide fraction에 분포되어 있는 것으로 나타났다. 세포내 protein 합성에 미치는 카드뮴의 영향을 조사한 결과, 카드뮴 무첨가배지에서 생장한 균체와 카드뮴이 함유된 배지에서 생장한 균체의 세포내 protein 함량은 카드뮴을 첨가함으로써 감소되었으나, ammonium sulfate($30{\sim}75%$ saturation)에 의하여 침전되는 soluble protein의 함량은 카드뮴을 첨가한 배지에서 생장한 균체에서 더 증가되었다. 고분자 가용성 단백질은 카드용 첨가배지에서 배양된 세포가 카드뮴 무첨가 배지에서 배양된 세포에 비하여 증가되었으나, 저분자 단백질 은 감소되었다. 따라서 세포내 protein의 합성은 카드뮴에 의하여 감소되었으나 ammonium sulfate(30-75% saturation)에 의하여 침전되는 고분자 단백질의 합성은 카드뮴에 의하여 촉진되는 것으로 나타났다.

• Journal of the Korean Wood Science and Technology
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• 제20권4호
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• pp.73-84
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• 1992

It was observed that the hot-water extract of the bark of Kalopanax pictus N. had the highest anti-complementary activity among the 11 kinds of forest materials. Methanol-and ethanol-soluble portions had low anti-complementary activities, but crude polysaccharide. HKP-0 had a high activity of 80%. HKP-0 contained 54.8% of total sugar and 27.9% of protein. The neutral sugars of HKP-0 consisted of mainly arabinose, galactose and glucose. HKP-4 fraction obtained by cetavlon treatment of HKP-0 showed the highest anti-complementary activity of 90%. The activity was not changed by pronase digestion bu decreased greatly by periodate oxidation. HKP-4 consisted of mainly arabinose and glucose with molar ratio of 1.0 : 22.4, HKP-4-I, an unabsorbed fraction from HKP-4 on DEAE Sepharose CL-6B column showed higher yield and activity than those of absorbed fractions. HKP-4-I was homogeneous, and its molecular weight was about 25,000. HKP-4-I contained 84.0% of neutral sugar and consisted of arabinose and glucose with molar ratio of 1.0 : 11.2. The anti-complementary activity of HKP-4-I was not decreased by the treatment of polymyxin B, and the polysaccharide activated both classical and alternative pathway in complement system. Void volume fraction obtained from HKP-4-I hydrolyzed with ${\alpha}$-amylase on Sephadex G-25 column only had a high anti-complementary activity.

• 한국식품과학회지
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• 제32권3호
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• pp.618-628
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• 2000

열처리 덱스트린을 내열성 ${\alpha}-amylase$로 가수분해함으로써 난소화성 텍스트린 I을 제조하였다. 황색 덱스트린으로부터 제조한 난소화성 덱스트린 I의 난소화성 획분과 식이섬유 함량의 평균치는 각각 50%와 25%였다. 또한, 열처리 덱스트린의 효소반응액으로부터 에탄올 처리에 의해 glucose를 포함하는 저분자의 당류를 제거함으로써 난소화성 덱스트린 II를 제조하였다. 초기 효소반응액의 80% 이상의 glucose와 maltose가 제거되어 난소화성 획분과 식이섬유 함량이 증가하였다. ${\alpha}-amylase$ 및 amyloglucosidase에 의한 황색 덱스트린의 가수분해액의 에탄올 침전으로 제조된 난소화성 덱스트린이 다른 효소 조합보다 높은 함량의 난소화성 획분 및 식이섬유를 나타내었으며, 각각 평균 83.6%와 62.8%였다. 따라서, 전분 가수분해 효소에 저항성을 갖는 난소화성 덱스트린은 열처리 덱스트린으로부터 용이하게 제조될 수 있으며, 수용성 식이섬유로서의 생리효과를 발휘할 수 있을 것으로 추정되었다.

• Food Science and Biotechnology
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• 제14권3호
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• pp.375-379
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• 2005

Physicochemical properties, intestinal microbial growth, and inhibitory effects of alcohol-insoluble polysaccharide (AIP) extracted from cucumber peel were investigated. AIP was composed of 14.54% crude protein, 1.04% crude lipid, 13.74 % crude ash, 9.1% soluble dietary fiber, and 41.2% insoluble dietary fiber. AIP showed low bulk density (0.18 g/mL) and water-holding capacity (6.39 g/g), and high oil-holding capacity (3.96 g/g). Pectic substance fractions [water-soluble pectic substance (WSP), ethylenediaminetetraacetic acid-soluble pectic substance (ESP), and alkali-soluble pectic substances (ASP)] and hemicellulose fractions [1 M KOH-soluble hemicellulose (KHP1) and 4 M KOH-soluble hemicellulose (KHP4)] were obtained from sequential chemical fractionation of AIP. WSP showed higher total sugar contents than total uronic acid contents, whereas opposite results were observed in ESP and ASP. Molecular weight distributions of three pectic substance fractions were in order of ASP>ESP>WSP. Ion exchange chromatogram pattern of WSP was different from those of ESP and ASP. Major component of WSP was fraction eluted by 0.05 M ammonium acetate buffer, whereas that of ESP and ASP was fraction eluted by 0.2 M NaOH. WSP and ASP showed growth-promoting activities against Lactobacillus brevis, Bifidobacterium bifidum, and B. longum, whereas B. bifidum and B. longum for ESP. KHP1 and KHP4 fractions had significant growth-promoting activities against B. bifidum.

• 생약학회지
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• 제16권4호
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• pp.221-226
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• 1985

To screen biologically active components of the higher fungi of Korea, the dried carpophores of Auricularia polytricha were extracted with water. The extract was examined for acute toxicity in ICR mice. A low molecular weight toxin of this fungus was purified by acetone precipitation followed by cellulose, silica gel and LH-20 Sephadex column chromatography. Major symptoms of this toxin were eye extrusion, hair erection, trembling of head, paralysis, rapid running or moving before death and depression of respiration. The median lethal doses of the total extract were 1.25 g/kg and 4.18 g/kg by i.p. and p.o. administrations, respectively. The amounts of one mouse lethal unit (MLU) of the total extract and final fraction that killed a 20-g mouse within 30 minutes were 28.5 mg/mouse and 12 mg/mouse, respectively.