• 한국식품조리과학회지
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• 제9권4호
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• pp.278-283
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• 1993

This study was attempted to investigate the effects of enzymatic modification of milk protein with protease on functional properties. The selected functional properties were solubility, emulsifying activity (EA), emulsion stability(ES), foam expansion(FE), and foam stability(FS). These properties were measu-red from pH 3.0 to pH 8.0. The proteases used in this study were iaolated from Meju(fermemted soybean) and had specific activity of 250 units/㎎ protein at pH 7.0, 1600 units of pretense was used for 1gr. of skim milk protein. Skim milk showed 30.5％ degree of hydrolysis for 1 hr. and 36.4% degree of hydrolysis for 3.5 hrs. of protease treatment at pH 7.0. Solubility of native skim milk, control, 1 hr. and 3.5 hrs. groups were 3.37, 3.64, 10.21, 14.34％o at pH 4.0 respcetively. The emulsifying activity of native skim milk, control, 1 hr. and 3.5 hrs. groups were 38.8,42.0,43.0,46.7ft at pH 4.0, respectively. Enzymatic modification resulted in the increase of solubility and emulsifying activity at pH 4.0. However at pH 5.0 emulsifying activity of 1 hr. and 3.5 hr. group were lower than native skim milk and control groups. 1 hr. protease treatment was found to be most effective way of increasing foam expansion at pH 4.0 to 6.0. It was supported that, protease treated skim milk can be used to improve solubility, emulsifying activity, foam expansion at acid pH. meju protease. skim milk, solubility, emulsion, foam.

• 청정기술
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• 제27권2호
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• pp.124-131
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• 2021

국제정치와 세계경제의 이슈가 되고 있는 '탄소중립'에 대한 선언이 전 세계적으로 이어지면서, 석유 기반 고분자를 생분해가 가능한 천연고분자로의 대체 연구가 활발히 진행되고 있다. 본 연구에서는 천연고분자 중에서도 세계에서 가장 많은 양을 차지하고 있는 나노셀룰로오스를 대체재로 제안하였다. 실란커플링제인 Glycidoxypropyl Trimethoxysilane (GPTMS)를 이용한 결정형 나노셀룰로오스의 표면작용기개질반응으로 하이브리드 나노셀룰로오스(hybrid nanocellulose, HNC)를 제조하였고, 저밀도폴리에틸렌(low density polyethylene, LDPE)과 함께 필름을 형성하였다. 친수성인 결정형나노셀룰로오스의 표면작용기개질반응을 확인하기 위해 소수성으로 바뀌는 것을 푸리에 변환 적외선 분광분석(fourier transform infrared spectrophotometer, FT-IR)과 친수/친유화도를 측정하였으며, 하이브리드 나노셀룰로오스를 적용한 고분자 복합체의 물성 확인을 위해 친수/친유화도, 인장강도, 투명도를 확인하였다. 석유기반 고분자와의 상용성은 pH 14에서 반응한 HNC가 LDPE 대비 1 wt%일 때, 인장강도와 투명도가 가장 우수하며, 결과적으로 실란커플링제를 이용한 나노셀룰로오스의 표면작용기개질이 가능하고 석유 기반 고분자와의 높은 상용성으로 인해 탄소중립을 위한 화석연료의 사용량을 줄일 수 있을 것으로 기대된다.

• 대한치과보철학회지
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• 제38권5호
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• pp.704-723
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• 2000

This study was undertaken to evaluate the tensile bond strength of In-Ceram alumina core treat-ed by ion assisted reaction(IAR). Ion assisted reaction is a prospective surface modification technique without damage by a keV low energy ion beam irradiation in reactive gas environments or reactive ion itself. 120 In-Ceram specimens were fabricated according to manufacturer's directions and divided into six groups by surface treatment methods of In-Ceram alumina core. SD group(control group): sandblasting SL group: sandblasting + silane treatment SC group: sandblasting + Siloc treatment IAR I group: sandblasting + Ion assisted reaction with argon ion and oxygen gas IAR II group: sandblasting + Ion assisted reaction with oxygen ion and oxygen gas IAR III group: sandblasting + Ion assisted reaction with oxygen ion only For measuring of tensile bond strength, pairs of specimens within a group were bonded with Panavia 21 resin cement using special device secured that the film thickness was $80{\mu}m$. The results of tensile strength were statistically analyzed with the SPSS release version 8.0 programs. Physical change like surface roughness of In-Ceram alumina core treated by ion assistad reaction was evaluated by Contact Angle Measurement, Scanning Electron Microscopy, Atomic Force Microscopy; chemical surface change was evaluated by X-ray Photoelectron Spectroscopy. The results as follows: 1. In tensile bond strength, there were no statistically significant differences with SC group, IAR groups and SL group except control group(P<0.05). 2. Contact angle measurement showed that wettability of In-Ceram alumina core was enhanced after IAR treatment. 3. SEM and AFM showed that surface roughness of In-Ceram alumina core was not changed after IAR treatment. 4. XPS showed that IAR treatment of In-Ceram alumina core was enabled to create a new functional layer. A keV IAR treatment of In-Ceram alumina core could enhanced tensile bond strength with resin cement. In the future, this ion assisted reaction may be used effectively in various dental materials as well as in In-Ceram to promote the bond strength to natural tooth structure.

• 한국식품조리과학회지
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• 제7권4호
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• pp.93-101
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• 1991

The object of this study was to investigate characteristics of kiwifruit protesae and effect of this enzyme on the functionality of casein. The specific activity of crudely prepared kiwifruit pretense on casein was 196.95 units/mg protein, it showed optimum activity at pH 3.0, $60^{\circ}C$. The degree of hydrolysis of casein with pretense treatment steeply increased to 73.5% and 78.9% for 10 and 20 minutes and then reached 84.1% and 89.3% for 1 and 4 hours, respectively. Solubility of non heated control group was 0.2% at pH 4, while the sample groups treated with enzyme for 0, 10 and 20 minutes were 14.5%, 19.2% and 24.0%, respectively. Casein treated with pretense showed marked increase in foam expansion near isoelectric point. However, enzymatically treated groups had lower foam expansion than the control groups. Foam stabilities of enzymatically modified group were lower than those of the control groups at all pH. Emulsifying activity of the non-heated control group was 0% at pH 4, while the groups modified enzymatically for 0, 10, and 60 minutes showed 51.0%, 55.5% and 54.5%, respectively.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.219.2-219.2
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• 2011

The oxyfluorination effects of electrospun carbon nanofibers (OFACFs) were investigated for $CO_2$ storage. Carbon nanofibers were prepared form poly acrylonitrile / N,N-dimethylformamide solution through electrospinning method and heat treatment. Chemical activation of carbon nanofibers were carried out in order to improve the pore structure. And the surface modification of activated carbon nanofibers was conducted by oxyfluorination to improve the $CO_2$ storage on effect of introduced functional groups. The samples were labeled CF (electrospun carbon nanofiber), ACF (activated carbon nanofibers), OFACF-1 ($F_2:O_2$ = 3:7), OFACF-2 ($F_2:O_2$ = 5:5) and OFACF-3 ($F_2:O_2$ = 7:3). The functional group of OFACFs was investigated by x-ray photoelectron spectroscopy analysis. The specific surface area, pore volume and pore size of OFACFs were calculated and pore shape was estimated by the BET equation. Through the adsorption isotherm, the specific surface area and pore volume significantly decreased by oxyfluorination.

• Carbon letters
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• 제9권1호
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• pp.23-27
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• 2008

The adsorption and reduction of Cr (VI) to Cr (III) by surface modified activated carbon (AC) in an aqueous solution was studied. The effects of surface modifications on the properties of the carbons were investigated by the analysis of specific surface area, carbon surface pH, acid/base surface values and functional groups. In order to understand the Cr(VI) adsorption and reduction ratio from Cr(VI) to Cr(III), the Cr adsorption capacity of AC was also measured and discussed by using inductively coupled plasma and UV spectrophotometer. The modifications bring about substantial variation in the chemical properties whereas the physical properties such as specific surface area, pore volume and pore size distribution nearly were not changed. Total Cr adsorption efficiency of as-received activated carbon (R-AC) and nitric acid treated activated carbon (N1-AC and N2-AC) were recorded on 98.2, 99.7 and 100%. Cr(III) reduction efficiency of R-AC increased largely from 0.4% to 28.3% compared to N1-AC and N2-AC.

• 한국염색가공학회지
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• 제27권1호
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• pp.18-26
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• 2015

para-aramid fibers were treated by atmosphere air plasma to improve the interfacial adhesion. The wettability of plasma-treated aramid fiber was observed by means of dynamic contact angle surface free energy measurement. Surface roughness were investigated with the help of scanning electron microscopy and atomic force microscopy. The tensile test of aramid fiber roving was carried out to determine the effect of plasma surface treatments on the mechanical properties of the fibers. A pull-out force test was carried out to observe the interfacial adhesion effect with matrix material. It was found that surface modification and a chemical component ratio of the aramid fibers improved wettability and adhesion characterization. After oxygen plasma, it was indicated that modified the surface roughness of aramid fiber increased mechanical interlocking between the fiber surface and vinylester resin. Consequently the oxygen plasma treatment is able to improve fiber-matrix adhesion through excited functional group and etching effect on fiber surface.

• 한국재료학회지
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• 제22권6호
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• pp.275-279
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• 2012

(3-mercaptopropyl)trimethoxysilane (MPTMS) was used as a silylation agent, and modified silica nanoparticles were prepared by solution polymerization. 2.0 g of silica nanoparticles, 150 ml of toluene, and 20 ml of MPTMS were put into a 300 ml flask, and these mixtures were dispersed with ultrasonic vibration for 60 min. 0.2 g of hydroquinone as an inhibitor and 1 to 2 drops of 2,6-dimethylpyridine as a catalyst were added into the mixture. The mixture was then stirred with a magnetic stirrer for 8 hrs. at room temperature. After the reaction, the mixture was centrifuged for 1 hr. at 6000rpm. After precipitation, 150 ml of ethanol was added, and ultrasonic vibration was applied for 30 min. After the ultrasonic vibration, centrifugation was carried out again for 1 hr. at 6000rpm. Organo-modification of silica nanoparticles with a ${\gamma}$-methacryloxypropyl functional group was successfully achieved by solution polymerization in the ethanol solution. The characteristics of the ${\gamma}$-mercaptopropyl modified silica nanoparticles (MPSN) were examined using X-ray photoelectron spectroscopy (XPS, THERMO VG SCIENTIFIC, MultiLab 2000), a laser scattering system (LSS, TOPCON Co., GLS-1000), Fourier transform infrared spectroscopy (FTIR, JASCO INTERNATIONL CO., FT/IR-4200), scanning electron microscopy (SEM, HITACHI, S-2400), an elemental analysis (EA, Elementar, Vario macro/micro) and a thermogravimetric analysis (TGA, Perkin Elmer, TGA 7, Pyris 1). From the analysis results, the content of the methacryloxypropyl group was 0.98 mmol/g and the conversion rate of acrylamide monomer was 93%. SEM analysis results showed that the organo-modification of ultra-fine particles effectively prevented their agglomeration and improved their dispensability.

• 폴리머
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• 제26권2호
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• pp.279-286
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• 2002

기능성고분자표면으로 개질하기 위해서 polyethylene(PE)표면에 아크릴산을 알곤 플라즈마를 이용하여 고정화와 그라프팅을 행하고 고정화와 그라프딩에 의한 개질효과를 ATR적외선스펙트럼의 분석, 접촉각과 접착강도 측정에 의하여 평가하였다. 아크릴산의 특성흡수띠와 접촉각의 현저한 감소사실로부터 친수성개질을 평가하였다. 그라프팅된 PE의 접촉각은 플라즈마처리시간에 따라서 무처리 PE에 비하여 47~$53^{\circ}$ 감소하였고 고정화된 PE는 이보다 작은 23~$26^{\circ}$ 감소하여 그라프팅이 고정화보다 더 효과적인 친수화 수단이 됨을 관찰할 수 있었다. 표면친수화의 정도는 플라즈마 처리시간과 방전출력에 강하게 의존하였다. 그라프팅의 경우 처리시간이 증가할수록 더욱 친수화되지만 고정화의 경우는 처리시간의 증가와 방전출력의 증가는 오히려 친수성을 감소시켰다. 개질된 PE표면의 peel test에 의한 접착강도측정 전파 역시 접촉각과 같은 경향을 나타내었다. 이러한 현상은 고정화과정 중에 아크릴산이 ablation되어 표면의 카복시친수성기가 감소하는 현상 때문으로 해석되었다.

• BMB Reports
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• 제40권2호
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• pp.135-141
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• 2007

Conjugation of the methyl group at the fifth carbon of cytosines within the palindromic dinucleotide 5'-CpG-3' sequence (DNA methylation) is the best studied epigenetic mechanism, which acts together with other epigenetic entities: histone modification, chromatin remodeling and microRNAs to shape the chromatin structure of DNA according to its functional state. The cancer genome is frequently characterized by hypermethylation of specific genes concurrently with an overall decrease in the level of 5-methyl cytosine, the pathological implication of which to the cancerous state has been well established. While the latest genome-wide technologies have been applied to classify and interpret the epigenetic layer of gene regulation in the physiological and disease states, the epigenetic testing has also been seriously explored in clinical practice for early detection, refining tumor staging and predicting disease recurrence. This critique reviews the latest research findings on the use of DNA methylation in cancer diagnosis, prognosis and staging/classification.