• KSBB Journal
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• 제31권2호
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• pp.126-134
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• 2016

To examine the possibility of using Musa sapientum L. (Banana) leaf extract as a cosmetic raw material, banana leaves grown in Jeju Island were extracted with 70% ethanol. Polysaccharides present in banana leaf extract were discarded by precipitation with cold ethanol. Polysaccharide-discarded banana leaf extract promoted procollagen and COL1A1 gene expression, but inhibited matrix metalloproteinase (MMP)-1 and MMP-2 gene expression in human skin fibroblasts when examined by real-time reverse-transcription polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). The active compound in banana leaves was identified by fractionation with various solvents. The chloroform fraction showed the highest anti-wrinkle efficacy and the active compound of chloroform fraction was identified as corosolic acid by NMR, FT-IR, EA, and HPLC-MS. In addition, banana leaf extract showed anti-oxidative efficacy with an IC50 value of 67.91 ppm, as determined by DPPH free radical scavenging assay. Finally, the anti-wrinkle efficacy of banana leaf extract-containing cream was confirmed by clinical tests. Based on these results, banana leaves could have an application as a cosmetic raw material with anti-wrinkle efficacy.

• 생명과학회지
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• 제13권2호
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• pp.223-229
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• 2003

국내산 무의 추출물을 여러가지 Column과 HPLC를 이용하여 잿빛곰팡이 병원균에 대한 항 진균성 물질을 분리하였다. 투석튜브를 이용한 분리에서 이물질이 3.5kDa 이하의 저분자물질이며 또한 내열성 물질임을 확인하였다. 이물질들은 최소한 5종의 물질로 구성되어 있으며 이중 가장 항진균성이 강한 물질을 HPLC를 이용하여 순수 분리하였으며 잿빛곰팡이병에 감염된 식물에 적용한 결과 농약과 비슷한 효과를 나타내어 환경 친화적인 항진균 물질로서 사용가능성을 확인하였다.

• 한국재료학회지
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• 제15권2호
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• pp.115-120
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• 2005

The aim of this research is to develop the TRIP aided high strength low carbon steels using reverse transformation process. The $4\~8\%$ Mn steel sheets were reversely transformed by slow heating to intercritical temperature region and furnace cooling to room temperature. The stability of retained austenite depends on the enrichment of carbon and manganese by diffusion during the reverse transformation. The amount of retained austenite formed after reversely transformed at $625^{\circ}C$ for 6 hrs was about $50\;vol.\%$ in the $8\%Mn$ steel. The change in volume fraction of retained austenite with a holding temperature was consistent with the changes in elongation and the strength-ductility combination. The maximum strength-ductility combination of 40,000 $MPa{\cdot}\%$ was obtained when the $8\%Mn$ steel reversely transformed at $625^{\circ}C$ for 12 hrs. However, it's property was significantly decreased at higher holding temperature of $675^{\circ}C$ resulting from the decrease of ductility.

• 한국재료학회지
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• 제11권5호
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• pp.431-437
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• 2001

본 연구는 제조공정을 달리한 0.14C-6.5Mn강을 2상영역에서 역변태처리 하였을 때 다량의 잔류오스테나이트를 생성시키기 위한 열처리 조건을 제시하고 잔류오스테나이트의 생성과 관련하여 미세조직 관찰, C, Mn의 분배거동 및 기계적성질을 조사하였다. 잔류오스테나이트는 역변태처리시 오스테나이트내에 C, Mn의 확산으로 농축되어 안정화되며 연성향상에 크게 기여한다. 30%이상의 잔류오스테나이트를 확보하기 위해서는 6457에서 역변태처리하는 것이 효과적이지만, 잔류오스테나이트의 부피 분율과 기계적안정성을 고려하면 $620^{\circ}C$에서 열처리하는 것이 바람직하다. 냉연재의 강도.연성조합값은 3강종 모두 $620^{\circ}C$에서 1시간 역변태처리한 경우 4000kg/$\textrm{mm}^2$정도로 매우 우수하지만 고온에서는 연성감소로 인하여 그 값이 현저하게 저하하였다. 0.14C-6.5Mn계 TRIP강에서 잔류오스테나이트 생성과 기계적성질에 미치는 1.1%Si 첨가효과는 매우 미약하였다.

• 한국가스학회:학술대회논문집
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• 한국가스학회 1997년도 추계학술발표회 논문집
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• pp.45-52
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• 1997

The objective of this study is, with concept of fitness-for-purpose, to evaluate the fracture toughness in X-grooved weld HAZ(heat-affected zone) of QLT(quenching, lamellarizing and tempering)-processed $9\%$ Ni steel, qualitatively and quantitatively, and analyze the relation with the change of microstructure. In general, CTOD test is widely used to determine the fracture toughness of steel weldments. But several problem of accuracy has been brought up. Therefore, in this study, modified CTOD test was used for X-grooved weld HAZ for $9\%$ Ni steel. Additionally, microstructure of HAZ is observed and analyzed by OM, SEM and XRD. From the resulty, HAZ toughness of QLT-$9\%$ Ni steel decreased as the evaluated region approaches the fusion line. The decreased toughness was partly caused by reduction of the retained austenite content, resulted from decreased nucleation site of the retained austenite content, resulted from decreased nucleasion site for reverse transformation due to the increasing fraction of coarse grained region. On the other hand, unexpectedly, the increasing fraction of ductile weld did not increase the HAZ toughness. Therefore, in this X-grooved weld HAZ, the primary factor affecting fracture toughness was the fraction of coarse grained region, i.e., the weakest region.

• 한국수산과학회지
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• 제34권5호
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• pp.556-562
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• 2001

본 연구에서는 비교적 성장이 빠르고 배양이 용이한 황갈편조 식물문 중 규조강에 속하는 P. tricornutum으로부터 선정하여 항 산화성 물질을 분리$\cdot$정제하여 물질의 구조를 밝혔다. P. tricornutum의 각 유기용매 추출물의 항산화성은 chloroform획분이 가장 좋았으며, 이 획분을 시료로 하여 silica gel column chromatography, PTLC 및 HPLC를 사용하여 항산화성 물질을 분리$\cdot$정제하였다. Silica gel column을 사용하여 분리된 획분의 항산화성은 dichloromethane: methanol (5: 1)로 용출시킨 획분에서 가장 높았으며, 이 획분의 PTLC 획분은 항산화성이 $20\%$ 증가하였다. 최종 정제된 물질의 $IC_50$값은 $8.3{\mu}g/mL$으로 화학적으로 합성된 항산화제인 BHT 및 BHA보다는 낮았지만 천연 항산화제인 $\alpha-tocopherol$보다는 다소 높게 나타났으며, 이 물질의 화학적 구조는 carotenoid류인 zeaxanthin으로 동정되었다.

• 한국수산과학회지
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• 제47권2호
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• pp.135-143
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• 2014

Exopeptidase active fractions from the hepatopancreas of the Argentina shortfin squid Illex argentinus, were obtained with acetone (AC 30-40%), ammonium sulfate (AS 60-70% saturation), anion exchange chromatography (AE-II, 0.2 M NaCl) and gel filtration chromatography (GF-I, 30-50 kDa) fractionation methods. A bitter peptide solution that has a bitterness equivalent to that of 2% glycylphenylalanine and prepared by tryptic hydrolysis of milk casein, was treated with the exopeptidase active fractions. The GF-I fraction was the best based on aminopeptidase activity (35.3 U/mg), percentage of recovery (30.7%) and a sensory evaluation (1.7). The amount of released amino acids increased as incubation time increased, and the bitterness of the enzyme reaction mixtures decreased. Incubation with the GF-I fraction for 24 h resulted in the hydrolysis of several peptides as revealed by the reverse-phase high performance liguid chromatography profile, with three peaks (3, 5 and 6) decreasing in area (%) and three peaks (1, 2 and 4) increasing in area (%). Therefore, the GF-I fraction appeared to be ideally suited to reduce bitterness in protein hydrolysates by catalyzing the hydrolysis of bitter peptides.

• Asian-Australasian Journal of Animal Sciences
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• 제15권6호
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• pp.793-799
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• 2002

Four feeds, three concentrates (rice bran, soybean meal and flaked corn) and one forage (corn silage) were incubated in four ruminally fistulated Holstein steers over three one week periods in a 3${\times}$4 incomplete latin square design where steers served as blocks and feeds as treatment. The objectives of the study were to investigate in situ DM, N and P degradability characteristics of feeds in order to assess availability of these nutrients by ruminants. In each period, all feeds were incubated in quadruplets (corn silage in triplicates) in the rumen of each steer in a reverse order for 3, 6, 9, 12, 18, 24 and 48 h. The DM 'a' fraction was higher and lower (p<0.001) in corn silage and rice bran respectively. Although corn silage contained the lowest (p<0.01) DM 'b' fraction, flaked corn contained the highest. Rate of DM degradation of flaked corn and corn silage were half (p<0.05) of the rate of DM degradation of either rice bran or soybean meal. Potential or effective DM degradability (p<0.05 to 0.001) at various passage rates were the lowest for rice bran and the highest for soybean meal. Corn silage N 'a' and 'b' was the highest and lowest, respectively (p<0.01). N 'c' of corn silage and rice bran was higher (p<0.001) than other feeds. Potential N degradability was the lowest in flaked corn (p<0.05). P 'a' was high (p<0.01) for corn silage and rice bran. P 'b' fraction was very high (p<0.001) in soybean meal but was absent in corn silage. Availability of DM (p<0.01 or 0.001), N (p<0.001) and P (p<0.05) differed between feeds at various passage rates except P availability at k=0.02 per h (p>0.05). The results demonstrate that the availability of DM, N and P by ruminants depends on feed as well as categories of animal.

• Journal of the Korean Wood Science and Technology
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• 제52권1호
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• pp.13-30
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• 2024

Swietenia mahagoni is one of the commercial timbers in Indonesia. Mahogany heartwood is an important characteristic as it relates to the natural durability and aesthetics of the wood. Lipophilic extractives are known to be involved in the heartwood formation process. Therefore, this study aims to determine the lipophilic compounds associated with heartwood formation. The n-hexane extract from sapwood and heartwood samples (1 to 5 years) was analyzed by gas chromatography-mass spectrometry. The results showed that the content of n-hexane extract ranged from 0.76% to 2.45% based on dry wood. The main group of compounds identified in the lipophilic fraction consisted of sterols (β-sitosterol, stigmasterol, campasterol, and cyclolaudenol), fatty acids (palmitic, oleic, linoleic, and stearic acid), and hydrocarbons (pentadecane, 1-octadecane, hexadecane, cyclotetracosane, cycloeicosane, and cyclooctacosane) after heartwood formation. In addition, the hydrocarbon fraction was the largest, followed by sterols, fatty acids, and 1-heneicosanol. In the radial variation, the distribution of fatty acids was greater in the sapwood than in the heartwood (4-year-old). However, the reverse pattern was found at the age of 5 years. The lipophilic fraction was generally more abundant in the heartwood compared to the sapwood, especially at 5 years of age, with much higher levels than when the heartwood was forming (4 years). These findings show that when the heartwood formation begins, the lipid composition was not fully metabolized at the beginning of heartwood formation compared to 5-year-old trees.

• 한국식품영양과학회지
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• 제33권2호
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• pp.229-235
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• 2004

콩 단백질을 효소로 가수분해하였을 때 생성되는 항균활성 Peptide를 조사하고 천연 항균제로서의 이용 가능성을 조사하기 위하여 본 실험을 실시하였다. 분리 콩 단백질에 5종의 단백질 가수분해 효소를 작용시켜 생성된 가수분해물의 항균력을 측정하고, membrane filter를 이용해서 한외여과 하여, 분자량별로 분리된 각 fraction의 항균활성을 측정하였으며, 항균활성이 가장 높은 분획을 high peformance liquid chromatography로 분취한 항균성 peptide의 항균활성을 측정하였다 분리 콩 단백질에 5종의 단백질 분해 효소를 작용시켜 제조한 가수분해물 중 Aspergilius saitoi protease로 작용시킨 것이 항균활성이 가장 높았다 Aspergillus saitoi protease로 작용시킨 콩 단백질의 가수분해물을 여과 한계량 10,000, 3,000, 1,000 membrane filter로 cut-off하여 한외여과한 각 fraction의 항균활성을 측정한 결과 분자량 1,000∼3,000인 fraction의 항균활성이 가장 높게 나타났다. Aspergillus saitoi protease로 작용시킨 콩 단백질의 분자량 1,000∼3,000 범위 가수분해물의 MIC는 0.5∼0.8 mg/mL였으며 그람 양성균과 음성균 모두의 증식을 억제하는 경향을 보였다. Aspergillus saitol protease로 작용시킨 콩 단백질의 가수분해물을 121$^{\circ}C$, 10분간 열처리하였을 때도 그 항균활성을 유지하는 것으로 보았을 때 이는 열에 대단히 안정함을 알 수 있었다. 한외여과하여 얻어진 콩 단백질의 분자량 1,000∼3,000범위 가수분해물을 동결건조하여 HPLC의 결과 얻어 진 peak 별로 분획 수집을 반복하여 항균 활성을 측정한 결과 retention time 16.02(IV)의 peak에서 최고 항균활성을 확인하였다.