• Title/Summary/Keyword: acid agent

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Electrochemical aspects of electroless nickel-boron plating (무전해 Ni 도금의 전기화학적 고찰)

  • 김영기;이원해
    • Journal of the Korean institute of surface engineering
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    • v.26 no.4
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    • pp.175-182
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    • 1993
  • Electroless plating of nickel was studied electrochemically in the presence of complexing agents. Nickel sulfate solution with dimethylamine borance(DMAB) as the reducing agent was used. Effects of temperature pH, concentration and complexing agents-citric acid, EDTA, tartaric acid-were studied.Experimental meas-urements showed that the rate of electroless nickel deposition was closely related to electrochemical parame-ters such as temdperature, pH, concentration and the properties of complexing agets.

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Clean Reduction of $\alpha,\beta$-Unsaturated Carboxylic Acid Derviatives to the Saturated Derivatives by Potassium Triphenylborohydride in the Presence of Phenol

  • Park, Soo-Bong;Kim, Kwan-Eung;Yoon, Nung-Min
    • Bulletin of the Korean Chemical Society
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    • v.9 no.6
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    • pp.352-355
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    • 1988
  • ${\alpha},{\beta}$-unsaturated carboxylic acid derivatives such as esters, amides, and nitriles are readily reduced to the corresponding saturated derivatives by potassium triphenylborohydride, $KPh_3BH$, in the presence of phenol, a quenching agent, in excellent yields.

Effect of Polyethylenimine Type in Polylactic acid Nanoparticles/DNA Complex on the Transfection Efficiency

  • Chae, Jong-Hyuck;Park, Yu-Mi;Kim, Kyeong-Man;Lee, Yong-Bok;Shin, Sang-Chul;Oh, In-Joon
    • Proceedings of the PSK Conference
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    • 2002.10a
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    • pp.425.1-425.1
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    • 2002
  • Nanoparticles of polylactic acid (PLA) and polyethylenimine (PEI) as an effective gene delivery agent were prepared and characterized. As a model plamid DNA. PME185/$\beta$-gal. a mammalian expression vector. and fluorescence enhancing protein (pEGHP) were used. The effects of PEI type on the physical properties of nanoparticles and transfection efficiency were examined. (omitted)

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Ring enlargement reaction of 5,6-dimethoxyindan-2-one

  • Ma, Eun-Sook;Jung, Won-Young;Choi, Tae-Young
    • Proceedings of the PSK Conference
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    • 2003.10b
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    • pp.181.1-181.1
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    • 2003
  • 2-Aminoindan derivatives has been shown the serotonergic activities. In order to find new serotonergic agent, we trid to enlarge the indan ring. 3, 4-Dimethoxybenzaldehyde, used as starting material was condensed with malonic acid, piperidine to form 3, 4-dimethoxycinnamic acid. It was catalytically hydrogenated and sudsequently cyclized by Friedel-Crafts acylation reaction to yield 5, 6-dimethoxyindanone. This compound was reacted with pyrrolidine and then acrylamide to be synthesized the 3-membered ring. (omitted)

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Method Development of Verapamil in Presence of NSAIDs using RP-HPLC Technique

  • Sultana, Najma;Arayne, M. Saeed;Waheed, Abdul
    • Bulletin of the Korean Chemical Society
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    • v.32 no.7
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    • pp.2274-2278
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    • 2011
  • Verapamil is a calcium channel blocker and is classified as a class IV anti-arrhythmic agent. It is used in the control of supra ventricular tachyarrhythmias, and in the management of classical and variant angina pectoris. It is also used in the treatment of hypertension and used as an important therapeutic agent for angina pectoris, ischemic heart disease, hypertension and hypertrophic cardiomyopathy. Verapamil commonly co-administered with NSAIDs (non-steroidal anti-inflammatory drugs) i.e. diclofenac sodium, flurbiprofen, Ibuprofen, mefanamic acid and meloxicam. A simple and rapid RP-HPLC method for simultaneous determination and quantification of verapamil and NSAIDs was developed and validated. The mobile phase constituted of acetonitrile: water (55:45) whose pH was adjusted at 2.7 and pumped at a flow rate of 2.0 mL $min^{-1}$ at 230 nm. The proposed method is simple, precise, accurate, low cost and least time consuming for the simultaneous determination of verapamil and NSAIDs which can be effectively applied for the analysis of human serum.

Bleaching of Hardwood Kraft Pulp by Xylanase Pretreatment

  • Cho, Nam-Seok
    • Journal of the Korean Wood Science and Technology
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    • v.27 no.4
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    • pp.65-71
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    • 1999
  • This study was carried out to investigate the effect of xylanase pretreatment of the unbleached hardwood kraft pulp during the conventional Chlorine-Extraction- Hypochlorite (CEH) bleaching on pulp property. Optimum bleaching condition was evaluated by using Novozym produced from the fungus Humicola insolens. Also the effect of chelating agent prior to enzyme treatment was analyzed. The kappa number of enzymatic bleached pulp at the enzyme charge 10 IU/ml was slightly similar to that of bleached pulp without enzyme. By enzyme treatment, the chlorine charge in conventional CEH bleaching process of hardwood KP could be reduced by 17%, while no adverse effect on pulp yield and strength was. The optimum condition for enzyme pretreatment was 10 IU/ml xylanase charge, 3 to 4 hrs treatment, and 2% pulp consistency. In sugar composition in the enzyme pretreated pulp, arabinose and mannose were not much different, but more xylose was retained. This high content of hemicellulose in pulp seems to play an important role in pulp properties. The pulp pretreatment by chelating agent prior to enzyme treatment could improve the enzyme activity and enhance the bleaching effect at 0.2% diethylenetriamine pentaacetic acid (DTPA) charges.

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Chestnut Extracts as new Anti-aging agent

  • 김범준;김정하
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.24 no.1
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    • pp.113-126
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    • 1998
  • Inner nutshell of Castanea crenata has been used as an anti-aging and anti-wrinkle agent from the ancient time in east Asia. In order to develop new anti-aging and anti-wrinkle, ethanolic extract of inner nutshell of Castanea crenata was prepared and various biological activities were evaluated. Cor-285 possessed potent tree radical scavenging activity in vitro compared to gallic acid. Cor-285 showed the preventive effect against UV-induced cytotoxicity of fibroblast at concentration of 25-250mg/ml. When Cor-285 was evaluated for its anti-allergic activity, it effectively inhibited histamine release from mast cells induced by compound 48/80. The inhibitory activity was stronger than that of glycyrrhizinate. Cor-285 also showed on vivo inhibition against delayed hypersensitivity as well as croton-oil induced ear edema in mice when topically applied. These results strongly suggest that Cor-285 may reduce immunoregulatory/inflammatory skin trouble. From the attempts to isolate the scavenger, were isolated. In a clinical trial of twenty healthy volunteers with aged skin, 6 weeks application of Cor-285 decreased wrinkle about 26% and increased moisturizing 20% on the skin. All of these results indicate that Cor-285 may be an effective anti-aging and anti-wrinkle agent.

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Fermentation and Quality Characteristics of Korean Traditional Cheongju by Different Mashing Methods (청주 제조시 담금방법에 따른 발효 및 품질 특성)

  • Bae, Gyun-Ho;Lee, Sang-Hyeon;Cheong, Chul
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.8
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    • pp.637-645
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    • 2016
  • This study was conducted to investigate the characteristics of fermentation and quality of Cheongju prepared by mashing using rice Nuruk inoculated with Aspergillus oryzae. Mashes were prepared by fermentation for 30-50 days using different amounts of fermenting agent, brewing water, milling ratios and fermenting temperatures. Adding fermenting agent at 15% resulted in slow fermentation, but a final alcohol content of 17% (v/v), similar to other samples tested. Addition of higher amounts of Nuruk resulted in increased amounts of citric acid, tartaric acid and malic acid, but low levels of succinic acid. Incomplete fermentation occurred when the ratio of brewing water was low, but the alcohol content (17%) of all samples was similar. When the amount of brewing water was high, the organic acid was levels were high. The speed of saccharification and fermentation was low when fermentation was conducted at $10^{\circ}C$, but the final alcohol content was the highest at this temperature. However, the content of n-propanol, isobutanol, isoamyl alcohol and organic acid was low at low temperature. At this time, the content of citric acid and malic acid was low, but the content of succinic acid was high. A higher milling degree resulted in a lower content of alcohol, organic acid and higher alcohols, with 10% milling resulting in a significantly higher content than the other samples.

Study on the Storage Stability of Horse Fat in Jeju (제주산 말지방(Horse Fat)의 저장 안정성 향상에 관한 연구)

  • Kim, Mi Seon;Yoon, Kyung-Sup
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.46 no.1
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    • pp.31-42
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    • 2020
  • Horse fat is known to be an effective ingredient in Asia, and the horse fat itself, which is mixed with other ingredients at the additive level, is often sold as a finished product. In this case, physical properties of the horse fat raw material are important. Many horse fats produced in Korea (Jeju) have low temperature stability, so if not stored at low temperatures, segregation may occur. In the case of Japanese horse fat, it is partially hydrogenated or is used the solid phase as the horse fat by separating the liquid phase and the solid phase that is harder and more stable than the horse fat of Jeju. In this study, the physical properties were tested to improve the temperature stability even without the partial hydrogenation process of Jeju horse fat. Various oil gelling agents were used in the study. Results confirmed that the physical properties of the hydroxystearic acid added Jeju horse fat were improved. In addition, stability evaluations at temperatures of 25 ℃, 40 ℃, 45 ℃ and flow behavior evaluations at temperatures of 25 ℃, 30 ℃, 40 ℃ were performed for Jeju horse fat with hydroxystearic acid, 100% Jeju horse fat, and 100% Japanese horse fat. Results showed that the Jeju horse fat improved in flow behavior by adding hydroxystearic acid similar to that of Japanese horse fat. In addition, when the crystal state was observed under a microscope, the thermal stability was improved by decreasing the size of the needle-type crystals with the addition of hydroxystearic acid. Jeju horse fat containing hydroxystearic acid was found to have no physical problems even when stored at room temperature for a long time.