• Food Science and Biotechnology
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• 제18권6호
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• pp.1435-1438
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• 2009

Hydrothermal treatment of rice hull was hydrothermal carried out at 105, 110, $121^{\circ}C$ for 15, 30, 60 min, respectively, using a conventional autoclave. Antioxidant activity of the hydrothermal treated rice hull extract was evaluated by determining total phenol contents (TPC), 1,1-diphenyl-2-picylhydrazyl (DPPH) radical scavenging activity (RSA), reducing power, and ABTS RSA. TPC, DPPH RSA, reducing power, and 2,2-azinobis(3-ethylenebenzothiozoline-6-sulfonic acid) (ABTS) RSA of the extract were significantly increased with increasing treated temperature and time. For example, hydrothermal extracts at $121^{\circ}C$ for 60 min increased the TPC, DPPH RSA, reducing power, and ABTS RSA to 0.840 mg/mL, 64.77%, 1.437, and 92.11%, respectively, while those of the extracts treated at $105^{\circ}C$ for 60 min were 0.508 mg/mL, 51.23%, 0.819, and 45.22%, respectively. The results indicated that hydrothermal treatment of rice hull was very effective to increase phenolic compounds and antioxidant activity of rice hull extract.

• 청정기술
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• 제24권3호
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• pp.206-211
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• 2018

Lead molybdate ($PbMoO_4$) were successfully synthesized using a facile surfactant-assisted hydrothermal process and characterized by XRD, Raman, PL, BET and DRS. We also investigated the photocatalytic activity of these materials for the decomposition of Rhodamine B under UV-light irradiation. From XRD and Raman results, well-crystallized $PbMoO_4$ crystals have been successfully synthesized with a facile surfactant-assisted hydrothermal process and had 52-69 nm particle size. The $PbMoO_4$ catalysts prepared at $160^{\circ}C$ showed the highest photocatalytic activity. The PL peak was appeared at about 540 nm at all catalysts and it was also shown that the excitonic PL signal was proportional to the photocatalytic activity for the decomposition of Rhodamine B.

• 대한화학회지
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• 제59권3호
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• pp.238-245
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• 2015

The crystallization and morphology change of amorphous titanias by hydrothermal treatment have been investigated. The amorphous titanias were prepared by pure water hydrolysis of two different precursors, titanium tetraisopropoxide (TTIP) and TTIP modified with acetic acid (HOAc) and characterized prior to hydrothermal treatment. In order to avoid complicate situation, the hydrothermal treatment was performed in a single solvent water with and without strong acids at various temperatures. The effects of strong acid, temperature and time were systematically investigated on the transformation of amorphous titania to crystalline TiO₂ under simple hydrothermal condition. Without strong acid the titanias were transformed into only anatase phase nanoparticle regardless of precursor type, temperature and time herein used (up to 250 ℃ and 48 hours). The treatment temperature and time effected only on the crystalline size, not on the crystal phase et al. However, it was clearly revealed that the strong acids such as HNO₃ and HCl catalyzed the formation of rutile phase depending on temperature. HCl was slightly better than HNO₃ in this catalytic activity. The morphology of rutile TiO₂ formed was also a little affected by the type of acid. The precursor modifier, HOAc slightly reduced the catalytic activity of the strong acids in rutile phase formation.

• 대한본초학회지
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• 제35권3호
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• pp.25-32
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• 2020

Objectives : At present, aging-related degenerative muscle diseases are considered a serious problem. However, the effects on muscles regarding the efficacy of blueberry have not been studied. In this study, we tried to find out the correlation between blueberry and muscle. Methods : 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) assay was performed to confirm the antioxidant efficacy of blueberry hydrothermal extract. To determine the effect of blueberry hydrothermal extracts (BHE) on myoblast activity, 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay was performed. To confirm the effect of blueberry hydrothermal extracts on the differentiation of myoblast into myotubes, protein expression levels of myosin heavy chain 3 (Myh3) and paired box 3/7 (pax3/7) were confirmed by immunoblot analysis. In addition, immunofluorescence microscopy was performed to confirm the effect on myotube formation of blueberry hydrothermal extracts. Results : Antioxidative efficacy and low toxicity were confirmed through ABTS assay and MTS assay of blueberry extract for myoblasts. As a result of immunoblot analysis and immunofluorescence analysis, the decrease in myogenic marker Pax3/7 was not confirmed, but myotubes The specific expression inhibitory activity of the forming protein Myh3 was confirmed. Through this, it was confirmed that the blueberry extract has a negative activity against myoblast differentiation. Conclusion : This experiment confirmed that blueberry hydrothermal extract has excellent antioxidant efficacy and negative results in inhibiting the differentiation and proliferation of myoblast. This requires deep study of certain ingredients and requires reassessment of the dietary intake of blueberries.

• Ocean and Polar Research
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• 제36권2호
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• pp.179-187
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• 2014

Directly searching for undiscovered hydrothermal vent sites is inefficient due to the practical difficulty of comprehensively imaging vent fields. Thus, most searches for hydrothermal vent sites rely on the detection of hydrothermal plumes from water column observation. Detecting and measuring the hydrothermal plumes are the most efficient way to infer the presence and distribution of hydrothermal vents. Both the array of vertical casting and lateral towing are the most common methods to discover hydrothermal plumes. In this study, we compared results of cast and tow-yo operations along the same section of a spreading center with a distance of 20.5 km in the North Fiji Basin for mapping hydrothermal plumes. Operation of CTD tow-yo provides a detailed pattern of plumes which enable us to locate the hydrothermal vents. On the other hand, identification of hydrothermal activity can be determined effectively by CTD cast with additional analysis of geochemical tracers. Reduction in the operating time is another advantage of CTD cast operation, especially for regional-scale survey. Our results show that the combination of CTD cast and tow-yo would improve the efficiency of the hydrothermal plume survey to locate new hydrothermal vent sites.

• 문화기술의 융합
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• 제7권4호
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• pp.845-855
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• 2021

본 연구는 보성에서 재배된 녹차잎을 감압증류와 열수추출법으로 추출하여 항산화, 항주름, 미백, 항균 in vitro 실험과 HPLC 분석을 수행하였다. 보성녹차 감압증류추출물은 주름개선(Elastase 활성 저해 실험)과, 미백(Mushroom tyrosinase 활성 저해 실험) 효능에서 우수한 결과를 나타내었으며, 열수추출물보다 낮은 농도에서 IC50 값이 측정되었다. 보성녹차 열수추출물은 항산화 시험(DPPH, ABTS+ radical 소거능, SOD 유사활성능, 총 폴리페놀 함량)에서 우수한 결과를 나타내었다. 항균 실험에서는 보성녹차 열수추출물에 의해 Staphylococcus aureus, Cutibacterium acnes 균주에 대하여 Clear zone이 형성되었다. HPLC 분석 결과로, EGCG와 Caffeine이 열수추출물에서 40.29 mg/g, 9.94 mg/g 검출되었고, 감압증류추출물에서는 Caffeine이 3.4 mg/g 검출되었다. 따라서 보성녹차 감압증류추출물은 주름개선과 미백효과가 탁월하며, 보성녹차 열수추출물은 항산화, 항균효과가 우수함을 확인하였다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2005년도 춘계학술발표대회 및 제8회 신소재 심포지엄 논문개요집
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• pp.219-219
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• 2005

• 한국세라믹학회지
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• 제50권6호
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• pp.504-509
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• 2013

In this study, ZnSe-$TiO_2$ composites were synthesized by a facile hydrothermal-assisted sol-gel process and characterized by nitrogen adsorption isotherms (77 K), X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis, transmission electron microscopy (TEM) and UV-vis diffuse reflectance spectrophotometry. The photocatalytic activity was investigated by decoloration methylene blue (MB), methyl orange (MO), and rhodamine B (Rh.B) in an aqueous solution under visible light irradiation. The results revealed that the photocatalytic activity of the ZnSe-$TiO_2$ photocatalyst was much higher than that of pure$TiO_2$. The ZnSe nanoparticles, which act as a photosensitizer, not only extend the spectral response of $TiO_2$ to the visible region but also reduce charge recombinations.

• 한국식품영양과학회지
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• 제42권10호
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• pp.1707-1711
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• 2013

수박을 과육, 외피, 내피로 나누어 $100{\sim}300^{\circ}C$에서 10, 30, 60분간 열수 추출하여 tyrosinase 저해활성과 신경세포 보호효과를 조사하였다. Tyrosinase 저해활성은 온도가 높을수록 시간이 증가할수록 높아졌으며, 과육과 외피에서 $300^{\circ}C$, 60분 처리했을 때, 약 93%로 가장 높은 저해활성을 보였다. $300^{\circ}C$에서 60분간 열수 추출한 수박 추출물을 PC12 세포주에 농도별로(10, 50, 100, 500 ${\mu}g/mL$) 처리하여 신경세포 보호효과를 확인하였다. 열수 추출을 하지 않은 수박 부위별 추출물은 $H_2O_2$ 처리군과 세포생존율의 유의적 차이가 없었으며 이를 통해 신경세포 보호효과가 없음을 확인하였으나, 열수 추출물들은 $H_2O_2$ 단독 처리군에 비해 세포생존율이 증가하였다. 이상의 결과들은 열수 처리가 수박에 함유된 유용 물질들의 추출에 매우 유용한 공정임을 시사한다.

• Ocean and Polar Research
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• 제42권1호
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• pp.33-47
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• 2020

The bulk and partition geochemistry was studied in two sediment cores collected from the axial valley of the north-central Fonualei Rift and Spreading Center (FRSC), Lau back-arc Basin, southwest Pacific. The sediments consist of mostly volcanic ash, although minor amounts of biogenic and other components were present in some intervals. The major element composition of bulk sediments recalculated to a carbonate-free basis was in good agreement with the magma compositions of the adjacent Tofua Arc and the FRSC, with only significant difference in Mn content. The enrichment of Mn and other associated elements (e.g. Cu, Co, Ni, and P) is attributed to hydrothermal input to the sediments, as evidenced by their significant partitioning in the non-detrital phases according to the partition geochemistry. Hydrogenetic and diagenetic inputs were assessed to be relatively insignificant. Estimated hydrothermal Mn fluxes during the Holocene ranged between 5.0 and 37.1 mg cm^-2 kyr^-1, with the higher values in younger sediments, suggesting enhanced hydrothermal activity. The hydrothermal Mn fluxes comparable to or higher than those reported from other spreading centers with strong hydrothermal activities may indicate the presence of unknown hydrothermal vent sites and/or topographic restriction on the dispersal of hydrothermal plumes in the northern part of the FRSC.