• Clean Technology
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• v.11 no.1
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• pp.51-56
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• 2005

In this paper we prepared dextrin dialdehyde (DAS) of a different oxidation ratio (aldehyde content) and examined their properties and discussed their tanning mechanism. DAS was produced by reacting dextrin in aqueous medium with periodate ion used in a molar ratio between periodate and glucose of 0.3 to 1.0 at a temperature of 20 to $45^{\circ}C$. Since DAS reacts with amino group, DAS may have tanning property of aldehyde tanning agent (formaldehyde, glutaraldehyde).

• Journal of the Korean Chemical Society
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• v.40 no.1
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• pp.65-71
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• 1996

The chemical behaviour of the Eu(Ⅲ) complexes with organic ligands(tris[3-(trifluoromethylhydroxymethylene-camphorato)]) and tris[3-heptafluoropropylhydroxymethylene-camphorato)] has been investigated by the UV/vis-spectrophotometric, magnetic, and electrochemcial methods. The two or three energy absorption bands are observed by the spectra of these complexes. The magnitude of crystal field splitting energy, the spin pair energy and strength were obtained from the spectra of the complexes. These complexes are found to be delocalization, low-spin state, and strong bonding strenth of electron configuration. The magnetic dipolemoment are found to be diamagnetic. The redox reaction processes of complexes were investigated by cyclic voltammetry in aprotic solvent. The redox reaction processes of complexes are turned out to be single or double reaction with respect to one electron diffusion current.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.12
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• pp.1912-1917
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• 2015

Pancreatic lipase is a potential therapeutic target for the treatment of diet-induced obesity in humans. As part of our continuing search for novel bioactive compounds, the convenient enzymatic transformation of caffeic acid into neolignans as well as related oxidized-products enhanced pancreatic lipase inhibitory activity. Enzymatic transformation of caffeic acid (1) using polyphenol oxidase originating from Korean pear yielded four oxidized metabolites, which were identified by different spectroscopic techniques ($^1H$,$^{13}C$ NMR, DEP/T, $^1H-^1H$ COSY, HMBC, HMQC, and NOESY). The anti-obesity efficacy of caffeic acid reactant was tested by in vitro porcine pancreatic lipase assay. All tested samples showed dose-dependent pancreatic lipase inhibitory activities. Four oxidative products including phellinsin A (2), caffeicinic acid (3), isocaffeicinic acid (4), and 7,8-erythro-caffeicin (5) were isolated and identified. The major metabolites (2~5) were evaluated for their pancreatic lipase inhibitory activity, and oxidized-products (2~3) improved potency against pancreatic lipase when compared to original caffeic acid. This result suggested that the neolignans isolated from oxidative transformation of caffeic acid might be beneficial in the treatment of obesity and relevant diseases, and the convenient enzymatic transformation by polyphenol oxidase may be a valuable method for structural modification and enhancement of activity.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.25 no.2
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• pp.77-127
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• 1999

활성 산소종은 노화, 특히 피부노화의 원인 물질로 작용하고 있다. 피부는 자외선에 노출되어 있어 활성 산소종을 만드는 광화학적 반응들이 계속해서 일어나고 있다. 이들 활성 산소종들은 피부 세포 및 조직 손상을 주도한다. 이들은 항산화 효소와 비효소적 항산화제들로 구성된 항산화 방어망을 파괴함으로써 산화제/항산화제 균형을 산화 상태 쪽으로 기울게 한다. 결과적으로 계속된 산화적 스트레스는 지질 과산화, 단백질 산화, 간질 성분을 파괴시키는 단백질분해효소의 활성화, 탄력 섬유인 콜라겐과 엘라스틴의 사슬절단 및 비정상적인 교차결합, 히아루론산 사슬의 절단, 멜라닌 생성반웅 촉진, DNA 산화와 같은 생체 구성 성분들의 손상을 야기시킨다. 결국에는 탄력감수 주름살 및 기미.주근깨 둥으로 특징 지워지는 피부노화가 가속화된다. 따라서 피부노화 방지를 위해서는, 과잉의 활성 산소종 생성을 억제하고 또한 생성된 활성산소를 효율적으로 제거할 수 있는 시스템이 화장품의 처방에 반드시 포함될 필요가 있다. 즉, 산화제/항산화제 밸런스가 유지되는 피부의 항산화 방어 시스템 구축이 필요하다. 피부노화 방지에 있어서 천연물의 역할로 (1) 자외선 흡수제로서의 역할, (2) 항산화제로서의 역할, (3) 주름 개선제로서의 역할, (4) 미백제로서의 역할, (5) 항균\ulcorner항염작용 및면역 조절제로서의 역할에 대하여 살펴 보았다. 21세기는 본격적으로 기능성 화장품 시대가 개막될 것으로 예측하고 있다. 이에 맞춰 천연물들은 피부노화를 방지하는데 주도적인 역할을 할 것으로 기대된다.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.11a
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• pp.315-316
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• 2003

대기중 광화학반응에서 생산되는 이차 생성물중의 하나인 $H_2O$$_2$(hydrogen peroxide)는 peroxy radicals간의 결합에 의해 생성된다. HO$_2$ + HO$_2$ $\longrightarrow$ $H_2O$$_2$+ $O_2$ 이렇게 생성된 $H_2O$$_2$는 대기중에서 주요 산화제로 작용하며, pH 4.5 이하 수용액 내에서 S(IV)를 S(VI)로 산화시켜 H$_2$SO$_4$(sulfuric acid)를 생성 한다. 또한 $H_2O$$_2$는 대기중에서 odd-hydrogen radicals(OH, HO$_2$, and RO$_2$)의 저장고 역할과 함께 odd-hydrogen radical의 생성과 소멸에 작용하여 대기의 산화력을 반영한다(Lee et al. 2000). (중략)

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2007.04a
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• pp.51-54
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• 2007

타겟 전압 제어를 통한 반응성 스퍼터링 방법과 유도결합 플라즈마(ICP: inductively coupled plasma)를 통해 산화알루미늄 박막을 증착하였다. 폴리카보네이트 기판과 산화알루미늄 박막사이의 접착력은 플라즈마 표면처리 하여 향상시켰다. 박막 특성은 ICP power 변화에 대한 경도, 구조, 밀도변화, 투과율, 증착속도, 표면 거칠기 및 잔류응력을 조사하여 보호코팅으로서 성능을 평가하였다.

• Applied Chemistry for Engineering
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• v.24 no.1
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• pp.87-92
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• 2013

Nonthermal plasma hybridized with photocatalysts is proven to be an effective tool to degrade toxic organics in wastewater. In this study, a specially designed dielectric barrier discharge (DBD) plasma system combined with photocatalysts was applied to decompose pestiticides such as dichlorovos, carbofuran and methidathon, which are frequently used in the golf courses and the orange plantations. The degradations of the pesticides in single and coupled systems were evaluated. The single system was used with ozone plasma which consisted of electrons, radicals, ions produced by oxygen gas and air, with and without ultra-violet (UV) irradiation, respectively. The coupled systems utilized the air-derived ozone plasma combined with zinc oxide, titanium dioxide and graphite oxide photocatalyst activated by UV. The graphite oxide was synthesized by a modified Hummer's method and characterized using FTIR spectrometer. It was elucidated that the plasma reaction with graphite oxide (0.01 g/L) brought about almost 100% of degradation degrees for dichlorovos and carbofuran in 60 min, as compared with the performances showed by no catalyst condition. The photocatalyst-hybridized plasma in the presence of UV irradiation was proven to be an effective alternative for degrading pesticides.

• Journal of the Korean Chemical Society
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• v.20 no.4
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• pp.295-298
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• 1976

The fact that a reaction between organothioenamine phosphonate and styrene oxide produces a derivative of cyclopropane has been proved by structural identification. This suggests that an anionic oxygen atom from the ring opening of the styrene oxide by nucleophilic attack of thioenamine phosphonate links to the phosphorous atom to from a betaine as an intermediate which is followed by cleavage of the weak P-C bond. The dextrorotatory optical activity of the product showed that the reaction was under the control of steric stability of the benzyl carbon in styrene which leads to the product through a sterically stable pathway.

• Korean Journal of Environmental Agriculture
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• v.22 no.2
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• pp.124-129
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• 2003

The objectives of this study are to manufacture an efficient $TiO_2$, photocatalyst and to delineate optimum operational parameters for TCE (trichloroethylene) degradation in a photocatalytic oxidative reactor. The $TiO_2$ photocatalyst irradiated by 365 nm UV light is expected to increase degradation of TCE in solution by a series of photocatalytic oxidations in the reactor. A new membrane $TiO_2$ photocatalyst wns eventually developed by coating a mixture of Davan-C(0.24 wt%) and PVA(0.16 wt%) on the surface of slips using the slip-casting method. Results show that increase in the number of coating of $TiO_2$ sol on surface of photocatalysts and in the surface thickness improved the endurance and photocatalysts, but these physical modifications caused significant decrease in the overall degradation efficiency of TCE. Pre-aeration or recirculation of the influents to the reactors containing TCE increased degradation efficiency of TCE. The optimum operational conditions far the surface area of photocatalysts and UV light intensity appeared to be $1.47\;mL/cm^2$ and $225\;W/cm^2{\times}100$, respectively, in the reactor. Based on the overall experimental results, the photocatalytic oxidation of TCE with the new membrane $TiO_2$ photocatalyst is found to be very effective under the operational conditions delineated in this study.

• Journal of the Korean Wood Science and Technology
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• v.25 no.3
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• pp.1-7
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• 1997

한국산 동백나무겨우살이(Pseudixus japonicus Hayata)에 존재하는 수용성 리그닌-탄수화물 복합체를 구성하는 다당류의 구조를 밝히고 리그닌 성분과 다당류의 결합양식을 구명하고자, 냉 온수 추출한 수용성 리그닌-탄수화물 복합체(M-LCC-WE)를 DEAE Sephadex A-50로 중성분획(M-LCC-N)과 산성분획(M-LCC-A), 나머지분획(M-LCC-R)으로 세분화한 후 M-LCC-N과 M-LCC-A에 대하여 메틸화, 아세틸화, 그리고 DDQ 산화반응을 실시하였다. M-LCC-N을 구성하는 다당류는 ($1{\rightarrow}4$) 글리코시드결합의 arabinan과 ($1{\rightarrow}4$)나 ($1{\rightarrow}6$) 글리코시드결합의 galactan과 glucan으로 M-LCC-A의 다당류는 ($1{\rightarrow}4$) 글리코시드결합의 arabinan과 ($1{\rightarrow}6$) 글리코시드결합의 galactan이 다당류 주성분으로 밝혀졌으며 galacturonic acid가 결합되어 있기 때문에 산성적 성질을 나타내고 있었다. 또한 M-LCC-A에서는 galacturonic acid 의 carboxyl 그룹이 리그닌의 ${\alpha}$-와 ${\gamma}$-위치에서 ester결합이 존재함이 확인되었다.