• Journal of the Korean Wood Science and Technology
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• 제51권1호
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• pp.14-22
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• 2023

Economical use of larix (larch) boards (grade 3) in industries is lower than that of imported hardwood; thus, studies have been conducted toward performance improvement of larix boards. Herein, flexural modulus of larix board samples laminated with wood adhesives polyurethane resins, poly (vinyl acetate) resins, phenol-resorcinol-formaldehyde resins, melamine-formaldehyde resins, and urea-formaldehyde resins was compared with that of the samples bonded with adhesives reinforced with mesh-type basalt fibers. Moreover, the flexural moduli of the laminated samples bonded by mesh-type basalt fibers were compared with those of reinforced samples. The results showed that boards laminated with polyurethane and urea-formaldehyde resin adhesives had higher flexural modulus than those without the lamination. In particular, the increase in the flexural modulus was relatively significant for the 2- and 3-ply board structures laminated with polyurethane adhesives compared to those with reinforcement. The 3-ply board structure without reinforcement had the highest flexural modulus when the urea-formaldehyde resin adhesive was used.

• 한국식품위생안전성학회지
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• 제14권1호
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• pp.76-83
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• 1999

Solid phase microextraction (SPME) was used for the determination of 6 standard solvents (methanol, isopropanol, methyl ethyl ketone, ethyl acetate, cyclohexane, toluene) in food packaging materials. SPME method is a solvent-free sample preparation technique in which a fused silica fiber coated with polymeric organic liquid is introduced into the headspace above the sample. SPME method using fiber coated polydimethylisiloxane (PDMS) was compared with static headspace (SHS) method used as a reference. It was found that the optimal adsorption condition using PDMS-SPME method was 2$0^{\circ}C$ for 15 minutes for the standard solvents. Detection limits, linearity, reproducibility and recovery of both SHS and PDMS-SPME methods have been determined using 6 standard solvents. Both methods were characterized by high reproducibility and good linearity. Using SHS methods, the mean recovery of the 6 standard solvents was ranged from 75.5% to 105.8% with a mean relative standard deviation (RSD) of 0.3% to 4.8%. With PDMS-SPME method, the mean recovery of the 6 standard solvents was ranged from 86.7% to 108.3% with a mean RSD of 0.4% to 2.5%. The detection limits of both methods were the same for toluene, cyclohexane and methyl ethyl ketone; those of PDMS-SPME method were higher than those of SHS method for methanol, isopropanol and ethyl acetate. PDMS-SPME fiber shoed excellent adsorption for non-polar solvents such as toluene, while it showed relatively low adsorption for polar solvents such as methanol.

• 한국결정성장학회지
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• 제14권5호
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• pp.187-192
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• 2004

We try to use isopropanol which has low boiling point to prepare ZnO thin films at low temperature. ZnO thin films were prepared by sol-gel spin-coating method using zinc acetate dehydrate-isopropanol-monoethanolamine (MEA) solution. The c-axis preferred orientation and optical properties of ZnO films with preheating temperature have been investigated. ZnO thin films were preheated at 200 to $300^{\circ}C$ with an interval of $25^{\circ}C$ and post-heated at $650^{\circ}C$. The ZnO film preheated at $275^{\circ}C$ and post-heated at $650^{\circ}C$ was highly oriented along c-axis (002) plane, and the surface with homogeneous and dense microstructures was formed having nano-sized grains. The optical transmittance was above 90 % in the visible range and exhibited absorption edges at 368 nm wavelength.

• Journal of Plant Biology
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• 제17권2호
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• pp.69-83
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• 1974

To elucidate the relationship between chemical structure and biological activity of alantolactone, and also to investigate the relationship between the growth of cells and the respiration of Chlorella pyrenoidosa affected by alantolactone, alantolactone and isoalantolactone were isolated from Inula helenium L., and di-, and tetrahydroalantolactones were prepared by the hydrogenation. At a concentration of 5$\times$10-5M alantolactone, the growth rate of Chlorella was greatly reduced. The viability of cells was also reduced over 50% within 2 hr at a concentration of 2.5$\times$10-4M alantolactone. However, oxygen uptake was increased by 20% over 3 hr. And 14CO2 production from glucose-1-14C, glucose-6-14C and 14C-acetate-U.L. was also increased by alantolactone. Biological activityof alantolactone was significantly reduced by cysteine, reduced glutathione or cystine but not by tryptophan or histidine. It was detected by spectrophotometrically and by TLC that alantolactone was also reacted with thiols except cystine. The solution of alantolactone reached with thiol gave the UV absorption spectrum of $\alpha$-saturated ${\gamma}$-lactone, and most of SH groups were disappeared by the addition reaction. From the reaction mixture of alantolactone and cysteine, a lactone adduct was isolated and purified. Isoalantolactone had shown similar activity as alantolactone, however, it was appeared that di-, and tetrahydroalantolactones were not only inactive biologically but also in vitro. It was concluded that there was no correlationship between increased respiration rate and mortality of Chlorella. During the respiration TCA cycle was activated, however it was uncertain that the activation of EMP or HMP was also appeared. Alantolactone and isoalantolactone were biologically active compounds but others were inactive. The reactivity of $\alpha$-methylene ${\gamma}$-lactone moiety toward SH group was principally responsible for its biological activity in sesquiterpene lactones.

• Food Science and Biotechnology
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• 제14권2호
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• pp.223-227
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• 2005

Anti-inflammatory assay was conducted on 20 kinds of traditional Indonesian medicinal herbs using soybean lipoxygenase (SLO) and hyaluronidase (HAse). Cinnamomun burmanni Bl showed highest anti-inflammatory activity. Ethyl acetate fraction from methanol extract of C. burmanni Bl bark showing high SLO inhibitory activity was isolated using silica gel-60 column chromatography. Two compounds were isolated and purified through preparative HPLC. Through analyses of UV, $^1H-NMR$, $^{13}C-NMR$, EI-MS and $FAB^+-MS$, compounds 1 and 2 were identified as coumarin and 2-hydroxy cinnamaldehyde, respectively, among which 2-hydroxy cinnamaldehyde showed SLO inhibitory activity of $IC_{50}\;=\;60\;{\mu}M$. Both compounds did not exhibit HAse inhibitory activity.

• 미생물학회지
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• 제28권4호
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• pp.324-330
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• 1990

The distribution of physicochemical environmental factors and microbiological factors was studied at 6 sampling sites in Kyeongge Bay of Yellow Sea from October 1989 to October 1990. The total bacterial number, saprophytic bacterial number, petroleum-degrading bacterial number, bacterial biomass, and bacterial secondary production were measured in the range of 0.09~1.24*10$^{7}$ cells/ml, 7~60000 CFUs/ml, 0~240 cells/ml, 14.16~301 .$\mu$g-C/l, and 0.13~11.82 mg-C/m$^{3}$/hr, respectively. The turnover times of $^{3}$H-glucose and $^{3}$H-acetate were in range of 6.5~6984 and 41~24897 hours, respectively. The spatial distribution of heterotrophic bacterial communities were hightly affected by influx of organic pollutants from the coastal area and the seawater exchange with offshore.

• Food Science and Biotechnology
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• 제14권1호
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• pp.89-93
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• 2005

Squalene synthase (SQS) inhibitors were screened from various plants and food extracts. Effective SQS inhibitor was purified from fermented soybean paste using ethanol extraction, HP-20 column chromatography, ethyl acetate extraction, silica gel column chromatography, and crystallization. Through UV spectrometry, $^1H$ NMR, $^{13}C$ NMR, and mass spectrometry, SQS inhibitor was identified as daidzein with molecular mass of 254 and molecular formula of $C_{15}H_{10}O_4$. Daidzein showed $IC_{50}$ value of 50 nmol/L against SQS, confirming its potential as therapeutic agent for hypercholesterolemia.

• 한국결정학회지
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• 제12권4호
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• pp.212-215
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• 2001

NaOAC·3H₂O 존재 하에서, manganese nitrate(Mn(NO₃)₂·H₂O )와 imidzole-4,5-dicarboxylic acid(IDCH₂)가 수열반응하여, 실험식 [Mn(IDC)(H₂O)]을 가지는 2차원 배위고분자 합성되었다. 화합물 1의 구조가 분광학적 방법(IR) 및 X-ray 회절법으로 규명되었다. 화합물의 1의 결정학적 자료: 사방정계 공간군 Pbca, a=7.257(5) Å b=13.687(5)Å, c=14.332(6)Å Z=8, R(wR₂)=0.0498(0.0999).

• 한국식품위생안전성학회지
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• 제28권2호
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• pp.89-94
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• 2013

마늘 숙성 중 생성되는 S-allylmercaptocysteine의 콜레스테롤 생합성 억제 효과에 대하여 Hepatocytes를 이용하여 조사하였다. HepG2 cells을 Dulbecco's modified Eagle's medium (DMEM)에 배양하여 S-allylmercaptocysteine의 농도를 20, 40, 60, 80 및 100 mL 씩 각각 첨가하여 cell viability를 살펴본 결과 20~40 ${\mu}g/mL$에서는 높았으며, 60 ${\mu}g/mL$ 농도에서 약 50%가 유지되었다. S-allylmercaptocysteine을 5, 10, 15 및 20 ${\mu}g/mL$ 농도로 [$^{14}C$]-acetatecholesterol에서 처리하였을 경우 15 ${\mu}g/mL$ 농도에서 cholesterol 생합성이 79%로 억제되었다. Fatty acid synthase의 활성은 0.95 nmol에서 19%의 억제효과를 나타내었으나, Glucose 6-phosphate dehydrogenase (G6PDH)의 활성에는 거의 영향을 미치지 않았다. S-allylmercaptocysteine의 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase의 활성은 용량 의존형으로 감소하였다. 이상의 결과로 보아 마늘 숙성 과정에서 생성되는 주요 성분인 S-allylmercaptocysteine은 간 세포에서 cholesterol의 생합성을 억제하는데 기여하는 것으로 나타났다.

• 전기화학회지
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• 제3권1호
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• pp.11-14
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• 2000

가시광선 영역에서의 높은 투과성과 우수한 전도성을 가진 전도성 ITO박막은 그 전기적 광학적 특성에 의해서 태양 전기 기판의 전극 재료나 Display소자의 투명전극으로 개발되고 있다. 이들의 제작은 현재 sputtering이 주종을 이루나 이들의 높은 생산비를 절감할 목적으로 sol-ge떫을 이용하여 ITO박막을 만들었다. ITO제조용 sol은 유기질 sol로는 indium tri-iso-propoxide를 ethylene glycol monoethyl ether에 녹인 후 $SnCl_4$를 dopant로 사용하여 제조하였다. Acetyl acetone을 넣어 sol이 수화되는 현상을 억제하였다. 무기질 sol로는 indium acetate를 n-propanol에 용해하여 사용하였다. Spin 방법을 이용하여 코팅하였으며 $500^{\circ}C$에서 열처리하였다. 가시 광선 영역에서의 투과도는 $90\%$ 이상을 얻었으며 비저항은 $0.01\Omega{\cdot}cm$가 측정되었다.