• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.71-71
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• 2012

As the critical dimensions of integrated circuits are scaled down, the line width and spacing between the metal interconnects are made smaller. The dielectric film used as insulation between the metal lines contributes to the resistance-capacitance (RC) time constant that governs the device speed. If the RC time delay, cross talk and lowering the power dissipation are to be reduced, the intermetal dielectric (IMD) films should have a low dielectric constant. The introduction of Cu and low-k dielectrics has incrementally improved the situation as compared to the conventional $Al/SiO_2$ technology by reducing both the resistivity and the capacitance between interconnects. Some of the potential candidate materials to be used as an ILD are organic and inorganic precursors such as hydrogensilsequioxane (HSQ), silsesquioxane (SSQ), methylsilsisequioxane (MSQ) and carbon doped silicon oxide (SiOCH), It has been shown that organic functional groups can dramatically decrease dielectric constant by increasing the free volume of films. Recently, various inorganic precursors have been used to prepare the SiOCH films. The k value of the material depends on the number of $CH_3$ groups built into the structure since they lower both polarity and density of the material by steric hindrance, which the replacement of Si-O bonds with Si-$CH_3$ (methyl group) bonds causes bulk porosity due to the formation of nano-sized voids within the silicon oxide matrix. In this talk, we will be introduce some properties of SiOC(-H) thin films deposited with the dimethyldimethoxysilane (DMDMS: $C_4H_{12}O_2Si$) and oxygen as precursors by using plasma-enhanced chemical vapor deposition with and without ultraviolet (UV) irradiation.

• 대한화장품학회지
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• 제39권2호
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• pp.89-96
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• 2013

본 연구에서는 폴리에틸렌아디페이트와 폴리메틸메타크릴레이트로 구성된 고분자 마이크로입자에 닥나무 뿌리 추출물을 함유시켜 닥나무 뿌리 추출물의 안정도와 상용성을 성공적으로 향상시켰다. 마이크로입자를 구성하는 고분자의 비율에 따라 마이크로입자에 함유된 닥나무 뿌리 추출물의 장기안정도에 미치는 영향을 평가하였다. 폴리에틸렌아디페이트 마이크로입자의 물리적 강도를 높여주기 위하여 폴리메틸메타크릴레이트를 도입하였으며, 이는 마이크로입자에 안정화시킨 닥나무 뿌리 추출물의 안정도에는 큰 영향이 없었다. 광학현미경, 편광현미경, 주사전자현미경을 이용하여 고분자 마이크로입자의 물리적 안정도를 관찰하였고, in vitro 실험을 통하여 고분자 마이크로입자로 안정화된 닥나무 뿌리 추출물의 미백 효과도 잘 유지되고 있음을 확인하였다.

• 한국작물학회지
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• 제51권1호
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• pp.89-94
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• 2006

Traditionally fatty acid composition used to be analysed by a GC and the sample preparation process includes lipid extraction from sample and subsequent methyl esters preparation, which are time-consuming and cumbersome. As an alternative, simultaneous extraction/methylation methods are being developed for rapid and simplified sample preparation. To optimize one-step extraction/methylation method for analysis of fatty acid composition in brown rice, various reaction factors such as sample to reaction solution ratio, reaction time and temperature, shaking intensity were changed and resultant fatty acid composition data were evaluated in comparison with previous reports. The ratio of sample weight to reaction solution volume was the most critical factor in that higher sample to reaction solution ratio caused overestimation of palmitic acid and linoleic acid composition, resulting in underestimation of oleic acid. Lower reaction temperature also induced overestimation of linoleic acid and underestimation of oleic acid. Reaction duration and the intensity of shaking prior to and during the reaction, however, caused no significant changes in analysis results. In conclusion, the optimum condition was mixing 5 grains (about 0.2 g) of brown rice with $680{\mu}L$ of extraction/methylation mixture and $400{\mu}L$ of heptane, followed by reaction at $80^{\circ}C$ for 2 hours.

• The Korean Journal of Physiology and Pharmacology
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• 제24권5호
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• pp.433-440
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• 2020

The substantia gelatinosa (SG) of the trigeminal subnucleus caudalis (Vc) is the first relay site for the orofacial nociceptive inputs via the thin myelinated Aδ and unmyelinated C primary afferent fibers. Borneol, one of the valuable time-honored herbal ingredients in traditional Chinese medicine, is a popular treatment for anxiety, anesthesia, and antinociception. However, to date, little is known as to how borneol acts on the SG neurons of the Vc. To close this gap, the whole-cell patch-clamp technique was applied to elucidate the antinociceptive mechanism responding for the actions of borneol on the SG neurons of the Vc in mice. In the voltage-clamp mode, holding at -60 mV, the borneol-induced non-desensitizing inward currents were not affected by tetrodotoxin, a voltage-gated Na⁺ channel blocker, 6-cyano-7-nitro-quinoxaline-2,3-dione, a non-N-methyl-ᴅ-aspartate (NMDA) glutamate receptor antagonist and DL-2-amino-5-phosphonopentanoic acid, an NMDA receptor antagonist. However, borneol-induced inward currents were partially decreased in the presence of picrotoxin, a γ-aminobutyric acid (GABA)_A receptor antagonist, or strychnine, a glycine receptor antagonist, and was almost suppressed in the presence of picrotoxin and strychnine. Though borneol did not show any effect on the glycine-induced inward currents, borneol enhanced GABA-mediated responses. Beside, borneol enhanced the GABA-induced hyperpolarization under the current-clamp mode. Altogether, we suggest that borneol contributes in part toward mediating the inhibitory GABA and glycine transmission on the SG neurons of the Vc and may serve as an herbal therapeutic for orofacial pain ailments.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2000년도 제18회 학술발표회 논문개요집
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• pp.170-170
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• 2000

Synthetic polymers such as polyimide, polycarbonate, and poly(methyl methacrylate) are long chain molecules which consist of carbon, hydrogen, and heteroatom linked together chemically. Recently, polymer surface can be modified by using a high energy ion beam process. High energy ions are introduced into polymer structure with high velocity and provide a high degree of chemical bonding between molecular chains. In high energy beam process the modified polymers have the highly crosslinked three-dimensionally connected rigid network structure and they showed significant improvements in electrical conductivity, in hardness and in resistance to wear and chemicals. Polyimide films (Kapton, types HN) with thickness of 50~100${\mu}{\textrm}{m}$ were used for investigations. They were treated with two different surface modification techniques: Plasma Source Ion Implantation (PSII) and conventional Ion Implantation. Polyimide films were implanted with different ion species such as Ar+, N+, C+, He+, and O+ with dose from 1 x 1015 to 1 x 1017 ions/cm2. Ion energy was varied from 10keV to 60keV for PSII experiment. Polyimide samples were also implanted with 1 MeV hydrogen, oxygen, nitrogen ions with a dose of 1x1015ions/cm2. This work provides the possibility for inducing conductivity in polyimide films by ion beam bombardment in the keloelectronvolt to megaelectronvolt energy range. The electrical properties of implanted polyimide were determined by four-point probe measurement. Depending on ion energy, doses, and ion type, the surface resistivity of the film is reduced by several orders of magnitude. Ion bombarded layers were characterized by Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS), XPS, and SEM.

• 약학회지
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• 제41권4호
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• pp.421-432
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• 1997

A new lectin was partially purified from starfish,Asterina pectinifera by means of physiological saline extraction, salt fractionation, ion exchange chromatography and hy droxyapatite chromatography, and it was named APL. The biochemical properties of the APL were characterized. In addition, its effects on lymphocyte mitogenicity and cancer cell agglutinability were tested. The APL agglutinated nonspecifically human erythrocytes and rabbit blood cells. Agglutinability was decreased to 30% of control activity below pH 5 and above pH 9 and was relatively unstable at increasing temperatures above 60$^{\circ}C$. The activity was reduced by addition of two kinds of metal ions, $Ba^{2+},\;Mn^{2+}$ and chelating agent, EDTA. APL was proved to be glycoproteins containing 9% sugars. For carbohydrate specificity, it was found that the activity of APL was inhibited by D(+)-glucosamine, D(+)-galactosamine, stachyose, N-acetyl-galactosamine and methyl-${\alpha}$-D-galactopyranoside among 35 sugars tested. In amino acid composition, the contents of acidic amino acids such as aspartic acid and glutamic acid were relatively high. This result suggest that the isoelectric point would be in a lower range. APL was found that it promotes the division of human lymphocytes. APL was proved to be a potent agglutinin for cancer cells such as HeLa, L929 and L1210 cells. Significant changes on the HeLa cell surfaces affected by APL were observed under the electron microscope.

• Journal of Applied Biological Chemistry
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• 제62권1호
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• pp.73-79
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• 2019

A novel esterase gene (est7S) was cloned from an enriched metagenomic library derived from an oil-spill area. The gene encoded a protein of 505 amino acids, and the molecular mass of the Est7S was estimated to be 54,512 Da with no signal peptide. Est7S showed the highest identity of 40% to an esterase from a sludge metagenome compared to the characterized enzymes with their properties, although it showed 99% identity to a carboxylesterase in the genome sequence of Alcanivorax borkumensis SK2. Est7S had catalytic triad residues, Ser183, Glu312, and His420, and the GESAG motif in most family VII lipolytic enzymes. Est7S was purified from the crude extract of clone SM7 using Sephacryl S-200 HR and HiTrap Q column chromatographies. The purified Est7S was optimally active at $50^{\circ}C$ and pH 10.0. Est7S showed a high specific activity of 366.7 U/mg protein. It preferred short length esters, particularly p-nitrophenyl acetate, efficiently hydrolyzed R- and S-enantiomers of methyl-3-hydroxy-2-methylpropionate, and glyceryl tributyrate. These properties of Est7S may provide potential merits in biotechnological applications such as detergent and paper processing under alkaline conditions.

• 농약과학회지
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• 제7권3호
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• pp.159-168
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• 2003

본 실험에서는 microtiter plate를 이용하는 실내 검정법을 이용하여 고추 탄저병균의 기주체 침입 초기에 볼 수 있는 형태 변화인 포자 발아 및 부착과 균사 생장에 미치는 다양한 화합물의 활성을 대량으로 검정할 수 있는 방법을 확립하였고, 기존의 몇 가지 살균제가 가지는 고추 탄저병균의 초기 형태 분화 에 대한 억제 효과를 조사하였다. 본 실내 검정법을 표준화하기 위하여 MTT와 propanol 처리, 접종하는 포자의 농도, 배양 시간들이 병원균의 흡광도에 미치는 영향을 조사하였다. MTT를 12 시간, propanol을 1 시간 처리하였을 때, 그리고 JC24 의 포자를 $1\times10^5$개/mL의 농도로 접종하고 36 시간 배양하였을 때, 병원균의 흡광도가 일관성 있고 높게 나타났다. 살균제의 작용 특성을 알아보기 위해서 6종의 보호용 살균제, 6종의 스테롤 생합성 저해 살균제, 1종의 호흡저해제를 선발하여 microtiter plate 대량 검정 방법에서 효과를 조사하였다. 보호용 살균제 중에서 mancozeb, chlorothalonil, dithianone 등은 $6.25{\mu}g/mL$ 처리구에서도 포자의 발아, 부착과 균사의 생장을 모두 80% 이상 억제하였으나, propineb, iminoctadine, fluazinam 등은 $100{\mu}g/mL$의 처리를 2 시간만에 세척하였을 때 흡광도가 감소하는 것으로 보아 포자 부착 억제 효과는 적었다. 6종의 스테롤 생합성 저해제 중에서 hexaconazole, tebuconazole, myclobutanil 등은 포자의 발아와 균사 생육을 억제하고, 세척할 경우 JC24의 생육 억제 효과가 떨어지는 것을 보아 부착 억제 효과는 기대할 수 없었다. Nuarimol 은 $100{\mu}g/mL$로 처리한 고농도에서만 부착에 대한 억제 효과가 54.7%로 다른 억제 효과보다 우수하였으나, $6.25{\mu}g/mL$의 저농도로 처리하였을 때는 부착 억제 효과가 나타나지 않았다. Kresoxim-methyl은 6.25와 $100{\mu}g/mL$의 농도에서 포자 부착에 대한 억제율이 27.3%와 54.4%로 나타났는데, 처리하는 농도가 높아짐에 따라서 효과도 증가하였다. 이상의 결과와 같이 때 microtiter plate를 사용하여 병원균이 식물체를 침입하는 초기에 나타나는 포자 발아와 부착, 그리고 균사 생장을 검정할 수 있었으며, 본 실험 방법을 통하여 Kresoxim-methyl은 탄저병균의 포자 부착을 특이적으로 억제하는 효과가 있음을 알 수 있었다.

• Journal of Preventive Medicine and Public Health
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• 제28권3호
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• pp.678-689
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• 1995

Chromium is one of the representative toxic substance by occupational exposure which damage the mucosa of respiratory tract including nasal septal perforation. The aim of this study is to evaluate the effect of chromium exposure on olfactory function and to obtain the fundamental information about chromium exposure. The authors performed olfactory function test, laboratory tests and questionnaire interview on the subject of three groups, that is, two exposed groups and one nonexposed group from May 1 to June 30, 1994. Exposed group 1 was 15 male workers without nasal septal perforation, exposed group 2 was 15 male workers with nasal septal perforation among 103 workers in 22 chromium plating factories, and nonexposed group was 15 male medical students. The gathered informations were histories of chromium exposure, habits of smoking and alcohol drinking, the concentrations of chromium in serum and urine, and asparate aminotransferase(AST), alanine aminotransferase(ALT), gamma-glutamyl transferase, etc. Olfactory function was checked by T and T olfectometer using phenyl ethyl alcohol(material A), methyl cyclopentenolone(material B), iso-valeric acid(material C), $\gamma$-undecalactone(material D), skatole(material E) and the results were expressed by detection threshold(DT) and recognition threshold(RT). There was a significant difference between exposed groups and nonexposed group in A, B, C, D, E substances by DT and in A, B, C, D substances by RT(P<0.01). The degree of olfactory dysfunction was highest in the exposed group 2 and lowest in the nonexposed group in all five substances by DT and it was same in A B, D substances RT and the difference of RT and DT. As summary, olfactory dysfunction by chromium exposure was recognized and the degree of olfactory dysfunction was higher in the exposed group with nasal septal perforation. Therefore, it would be helpful to apply olfactory function test for the early detection of olfactory dysfunction, and this test would be considered as the basic tool within workers' compensation system.

• The Korean Journal of Physiology and Pharmacology
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• 제4권5호
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• pp.369-378
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• 2000

This study was undertaken to investigate an involvement of nitroxergic innervation in gastric smooth muscle of rat. Isometric tension study, the measurement of single cell length, NADPH diaphorase stain of smooth muscle layers and neuronal nitric oxide synthase (nNOS) western blotting were performed. Sodium nitroprusside (SNP), a nitric oxide donor, relaxed the muscle strips precontracted by acetylcholine (ACh) in a concentration-dependent manner. Pretreatment of L-arginine decreased the contraction induced by electric field stimulation (EFS). Pretreatment of $N^G-nitro-L-arginine$ methyl ester (L-NAME), a NOS inhibitor, increased the EFS-induced contractions. LY 83583, a guanylate cyclase (GC) inhibitor, reversed the inhibitory actions of L-arginine on the muscle contractions. The effects of L-Arginine, L-NAME and LY 83583 on ACh-induced contractions were not significant. L-arginine reduced the EFS-induced contraction in circular muscle, whereas L-NAME enhanced the EFS-induced contraction in longitudinal strips. By EFS, the phasic contractions appeared approximately $20{\sim}25$ seconds later. L-NAME significantly shortened the delay time to about $2{\sim}3$ seconds. In single cell study, ACh contracted gastric smooth muscle cells, SNP relaxed the cells, and the latter also inhibited the ACh-induced contraction. LY 83583 enhanced the ACh-induced contraction and antagonized SNP-induced relaxation. NADPH diaphorase activity was assessed by a histochemistry, nitroblue tetrazolium (NTB) staining. Positive staining was observed in both circular and longitudinal muscle layers. L-arginine increased the staining, while L-NAME decreased the staining. Western blotting for nNOS proved the presence of nNOS in rat gastric smooth muscle. EFS and additional $Ca^{2+}$ increased nNOS protein expression. These results suggest that in rat stomach, both circular and longitudinal muscle layers are innervated with nitroxergic nerves which relax the gastric smooth muscle via NO-cGMP pathway.