• Elastomers and Composites
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• v.46 no.2
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• pp.125-131
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• 2011

The effects of chopped kenaf fiber concentration on mechanical property of polypropylene (PP) composite are investigated. The addition of kenaf increased the tensile strength, flexural modulus, impact strength, specific gravity, and HDT, while decreased the elongation%, flexural strength, and melt flow index. The increase of mechanical properties is due to increased surface area contacting between fiber and polymer matrix and fiber-fiber interaction. Volatile extractives in the kenaf seemed to decrease the interfacial adhesion between kenaf surface and PP.

• Journal of the Korean Wood Science and Technology
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• v.22 no.1
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• pp.28-33
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• 1994

The chemical compositions of pine bark from mechanical pulp industry were determined, and effect of Ca base acid sulfite on bark cooking was investigated under various conditions. The pine bark was composed of 39.5 % alkali extractives, 50.3 % lignin, and a small amount of carbohydrate. The contents of alkali extractives and lignin were remarkably higher than those of pine wood. The bark was composed of high content of arabinose and xylose, while the wood was composed of high content of mannose. When pine bark was cooked with 75 % free acid at 145 $^{\circ}C$, the rate of cooking and delignification was improved with the increase of total acid, but it was very difficult to delignify the bark by 50 % and over under these conditions. In the presence of 60~65 % free acid and at 155~165 $^{\circ}C$, initial cooking rate, delignification, and delignification selectivity were considerably increased, but condensation reaction of lignin was considerable at the end of cooking. Therefore, it was shown that pine bark was very difficult to delignify by the Ca-base acid sulfite cooking.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.11b
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• pp.115-119
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• 1999

During mechanical pulp production and blcaching wood components, such as extractives, carbohydrates and lignin are dissolved and dispersed into the process waters. These components are called dissolved and colloidal substances(DCS). DCS can accumulate during water circulation and can in turn affect paper machine runnability and also the strength and optical properties of the paper. In this work DCS fraction origination from TMP process were treated with enzymes acting on triglycerides. glucomannans, and lignin and the effect of enzymatic treatments on the water composition as well as sheet properies were evaluated. Lipases were found to modify the chemical structure of the extractives resulting in more hydrophilic fibre surface and subsequent improvement in the sheet strength properties. Mannanase treatment, on the other hand, destabilized pitch. As a result, aggregation of pitch to the fibres was observed which in turn resulted in impaired strength properties. Laccase could effectively polymerize lignans and the reaction products seemed to be sorbed onto the fibres.

• Advances in Traditional Medicine
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• v.8 no.1
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• pp.53-58
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• 2008

The plant Quisqualis indica (Compositae) has ehnopharmcological reputation of being used as a healing agent in Bangladesh. In this study, preliminary screenings were conducted to look at the antimicrobial susceptibility and cytotoxicity of the plant extract. The extractives of the plant were subjected to screening for inhibition of microbial growth by the disc diffusion method. The zones of inhibition demonstrated by the n-hexane, carbon tetrachloride, chloroform and aqueous soluble partitionates of the methanolic extract ranged from 8 - 15 mm, 8 - 18 mm, 12 - 20 mm and 10 - 16 mm, respectively at a concentration of 400 ${\mu}g$/disc. All the extractives were also subjected to brine shrimp lethality bioassay for primary cytotoxicity evaluation. Here, the carbon tetrachloride soluble materials demonstrated the highest cytotoxicity with $LC_{50}$ of 0.826 ${\mu}g$/ml, while n-hexane, chloroform and aqueous soluble partitionates of the methanolic extract revealed the $LC_{50}$ of 1.254, 3.866 and 5.366 ${\mu}g$/ml, respectively. This is the first report of the antimicrobial activity and cytotoxicity Q. indica.

• Advances in Traditional Medicine
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• v.8 no.1
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• pp.97-102
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• 2008

A total of five compounds namely, 2-methylanthracene-9, 10-dione (1), 1-hydroxy-6-methylanthracene-9,10-dione (2), $\beta$-sitosterol (3), stigmasterol (4) and sitosterone (5) were isolated from the stem extracts of Polygonum lanatum for the first time. The structures of the isolated compounds (1-5) were established by extensive spectroscopic studies, including 2D NMR such as $^{1}H-^{1}H$ COSY, HSQC and HMBC studies. The crude extracts and purified compound (1) were screened for antimicrobial activity against a wide range of Gram-positive and Gram-negative bacteria and fungi by the disc diffusion method. The n-hexane and dichloromethane soluble partitionates of the methanolic extract revealed mild to moderate inhibition of growth of the test organisms. The cytotoxic potential of the extractives and compound 1 was also determined by using brine shrimp lethality bioassay, where the extractives demonstrated significant cytotoxic activities.

• Journal of the Korean Wood Science and Technology
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• v.29 no.4
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• pp.48-52
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• 2001

The needles of Pinus densiflora, grown in the campus of Kangwon National University were collected, extracted with acetone-$H_2O$ (7:3, v/v) and freeze dried to give 10.4 g of ethylacetate soluble powder. A portion of the freeze dried powder was chromatographed on a Sephadex LH-20 column using a series of aqueous methanol and ethanol, and ethanol-hexane mixture as eluents. The extractives contained a large amount of flavan compounds in addition to a small amount of flavonoid derivatives such as kaempferol-3-O-glucopyranoside, and quercetin-(6"-O-acetyl)-glucopyranoside which has not been isolated from this species yet. Some spectrometric analyses such as NMR and FAB-MS were performed to identify the structures of the isolated flavonoid derivatives.

• Journal of Korea Foresty Energy
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• v.21 no.1
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• pp.41-48
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• 2002

The barks of oak trees (Quercus acutissima and Quercus variabilis) were collected, extracted with acetone-$H_2O$ (7:3, v/v), fractionated with hexane, $CH^2C1^2$ EtOAc and -$H_2O$, then freeze dried to give dark brown powder. The EtOAc soluble mixtures of the trees were chromatographed on a Sephadex LH-20 column using a series of aqueous methanol and ethanol-hexane mixture as eluents. The structures of isolated compounds were characterized by $^1H$, $^13C$ and 2D-NMR spectroscopy and molecular weights were determined by FAB-MS spectra. The isolated compounds from Quercus acutissima were (+)-catechin, (+)-gallocatechin, gallic acid and taxifolin-3-O-$\beta$-D-glucopyranoside and the compounds from Quercus variahilis (+)-catechin, caffeic acid and taxifolin-3-O-$\beta$-D-glucopyranoside.

• Journal of Korea Foresty Energy
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• v.22 no.1
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• pp.30-36
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• 2003

2kg of pollen extracted with EtOH(98%), concentrated, and fractionated with a series of hexane, CH$_2$Cl$_2$ EtOAc and $H_2O$ on a separately funnel. Each fraction was freeze dried to give dark-brown powder and EtOAc soluble portion of the powder was chromatographed on a Sephadex LH-20 column using a series of aqueous methanol as eluents. Spectrometric analysis such as NMR and FAB-MS including TLC were performed to characterize the structures of isolated compounds. Pollen contained a small amount of flavonol derivatives such as quercetin-3-O-$\beta$-D-glucopyranoside and kaempferol-3-O-$\beta$-D-rutinoside in addition to a small amount of flavanonol compound such as aromadendrin-5-methyl ether and acid compound such as.

• Journal of the Korean Wood Science and Technology
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• v.31 no.1
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• pp.16-21
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• 2003

The methanol extractives from root bark of Ulmus davidiana var japonica nakai were fractionated with n-hexane, ethyl ether, ethyl acetate and waster, the water soluble fraction was also fractionated with silicagel column chromatograhy. The chemical structure of purifided compounds were identified with UV, IR, ¹H-NMR and ¹³C-NMR spectra and the antibacterial activities also were investigated. Two different antibacterial compounds (compound A and B) were fractionated with silicagel chromatography and TLC. Compounds B was identified as a catechin rahmnoside. The both of compounds had antibacterial activity on Staphylococcus aureus and Salmonella typhimurium.

• Journal of the Korean Wood Science and Technology
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• v.30 no.3
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• pp.109-115
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• 2002

Mycelial growth of L. edodes by pretreatments of softwood was studied on a sawdust medium. The sawdust used was from the following softwood species : Larix leptolepis, Pinus densiflora and Pinus koraiensis. The pretreatment consisted of cold-water (48 h), hot-water (3 h) and steam extractions (3 h) at a ratio of 500 g : 3,000 mL (sawdust : distilled water). The sawdust medium was a mixture of 76% sawdust, 20% rice bran, 3% glucose, 0.4% potassium nitrate and 0.6% calcium carbonate. Following sawdust pretreatments proved most suitable : L. leptolepis (steam extraction), P. densiflora (hot-water extraction) and P. koraiensis (hot-water extraction). Mycelial growth on P. koraiensis sawdust increased in proportion to an increase in hot-water extraction time. Mycelial growth was optimum on the sawdust extracted for 12 hours, hot-water extraction beyond this period proved unsuitable. With the exception of P. densiflora at 100 ㎍/mL, antifungal activity occurred in every sample. Maximum inhibition of mycelial growth was obtained from following concentration of hot-water extractives : P. densiflora (10⁴ ㎍/mL) and P. koraiensis (10⁴ ㎍/mL). This study has provided useful preliminary information for the cultivation of L. edodes.