• Natural Product Sciences
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• v.10 no.5
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• pp.244-247
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• 2004

The inhibitory effects of the leaves of Eucalyptus darylmpleana (Myrtaceae) on the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical was examined. The scavenging effect of the ethyl acetate fraction of Eucalyptus darylmpleana leaves on DPPH radical was stronger than the other fractions, and further purified by silica gel and Sephadex LH-20 column chromatography. 3,4-Dihydroxybenzoic acid, gallic acid, quercetin, quercetin $3-O-{\alpha}-_L-rhamnoside$, quercetin $3-O-{\beta}-_D-glucoside$ and quercetin 3-O-rutinoside were isolated and elucidated by spectroscopic data. Among these components, gallic acid and quercetin $3-O-{\alpha}-_L-rhamnoside$ exhibited potent scavenging activities on DPPH radical with $IC_{50}$ values of 6.02 and $5.54\;{\mu}M$, respectively.

• Journal of the Korea Furniture Society
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• v.23 no.3
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• pp.298-304
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• 2012

Since 1990's, a flooring based on plywood has gotten customers' demand. Costs of raw material and production increased because of changed environment of industry. Tropical timber such as Red Meranti (Shorea acuminate) used for raw material of the floor has been depleting beside countries in South Eastern Asia changed species of afforestation. As a result, it gets hard to secure good quality of raw material for plywood. Moreover plywood price is increased suddenly after earthquake in Japan. Eucalyptus (Eucalyptus globulus) in china has been using for raw material as a countermeasure of changed environment of industry. In this study, possibility of using flooring consisted of Eucalyptus veneer as a core layer was checked by heat transfer experiments. Flooring consisted of Red Meranti was used for comparison. Two factors which impact on heat transfer are a type of density gradient and density difference between Long-grain veneer and Short-grain veneer. Red Meranti samples are 'M' type of density gradient on the other hand Eucalyptus samples are 'W' type of density gradient.

• Journal of Plant Biotechnology
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• v.30 no.3
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• pp.269-273
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• 2003

In order to develop an efficient micropropagation protocal for Eucalyptus pellita, on in vitro culture system has been was established by inducing axillary buds from greenhouse stock materials. Among 6different media tested, DKW medium was the best ot induce bast induce both shoot proliferation and growth. Average number of proliferated shoots of 403per explant was obtained at the concentration of 0.1mg/LBA. Most of the stem materials excreted phenolic compounds at the proximal part of the explant and caused darking of the media. Therefore, it was necessary to transfer frequently to a fresh medium and/or to add activated charcoal at the concentration of 0.02％(w/v). Generally on vitro roots were formed easily on 1/2DKW medium with NAA treatment. All the explants rooted at the medium containing 0.2mg/L NAA and displayed vigorous root growth in vitro culture conditions. After transferred to an artificial soil mixture (peatmoss: vermiculrite: perlite, 1:1:1, v/v/v) in the greenhouse, most rooted plantlets survived well without any morphological abnormalities. The results show that the species can be micropropagated effectively by the application of axillary bud culture system.

• Journal of the Korean Wood Science and Technology
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• v.39 no.2
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• pp.148-155
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• 2011

Thermal treatment techniques are used for modifying wood and wood-based materials to improve dimensional stability and hygroscopicity. This study investigated the effects of press pressure and temperature on density, vertical density profile, thickness swelling and surface hardness of eucalyptus wood boards. The experimental wood boards were prepared from Turkish River Gum ($Eucalyptus$ $camaldulensis$ Dehn.). The surface hardness value increased with increasing press pressure in the treated groups. The application of a higher pressure at the same temperature level increased the amount of swelling of wood. It means that it is not needed for application of higher pressure to enhance the dimensional stability of wood. It is expected that it is possible to produce increased hardness, dimensional stability and durability by application of hot pressing treatment. This research showed that different press pressure and temperature values should be used to improve the performance properties of eucalyptus wood so that the end-use of the wood materials could be expanded.

• Journal of the Korea Convergence Society
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• v.9 no.7
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• pp.149-154
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• 2018

This article intended to examine the anti-plaque activity of 4 essential oils of Lavender, Tea tree, Eucalyptus, Lemongrass against Streptococcus mutans. In the results of measuring the anti-plaque effect against Streptococcus mutans, Minimum anti-adhesive concentration of Lavender oil was 1.0% and that of Tea tree, Eucalyptus, lemongrass essential oils was 0.5 %. Also, it was confirmed that the essential oils have the effect of inhibiting acid generation by Streptococcus mutans. It was confirmed that pH of the concentration was lowered by the acid generation under the MAC by measuring pH of the solution after incubating Streptococcus mutans and the essential oils in the thermostatic bath varying their concentration. From these results, the essential oils, particularly, Tea tree, Eucalyptus, Lemongrass essential oils are the natural material inhibiting the plaque generation and the potential that they can be used to develop the oral care products was confirmed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.5C
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• pp.420-428
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• 2012

One of the most important means in modern NQ emphasized smart society is the communication skill. Especially, effects on improving pronunciation accuracy, it is mostly necessary to accurately express his or her own idea due to the personal relation influence 38% of voice. For this, this paper proposed the voice influence analysis of carbonate drink and eucalyptus fragrance. In particular, in the case of carbonate drink, the amounts of drinking accumulation is verified for analysing the drinking accumulation influence. Also, eucalyptus fragrance is reported for influencing the pronunciation accuracy. For this, jitter, shimmer, pitch and intensity of voice is analyzed. Finally, we accomplish an voice analysis of quantization, objective and visualization for such carbonate drink and eucalyptus fragrance.

• Journal of Life Science
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• v.16 no.1
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• pp.162-167
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• 2006

Aromatherpy is the controlled use of essential oils to promote health and well-being. In this work we have investigated the effect of eucalyptus and geranium on the production of interleukin-2 (IL-2) and interleukin4 (IL-4). Mouse splenocytes were incubated with essential oils. The culture supernatants of mouse splenocytes exposed with these oils were harvested to assay IL-2 and IL-4 production. The quantitative changes of IL-2 in splenocytes culture supernatants after exposure with these oils were decreased at high doses, but increased at low doses. But its of IL-4 were increased generally at high doses of eucalyptus. In case of the exposure of geranium, its of IL-4 were dose-dependently increased. These kinds of essential oils showed the probability to improve IL-2- and IL-4-related immune responses at the optimum exposure.

• Microbiology and Biotechnology Letters
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• v.48 no.2
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• pp.148-157
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• 2020

Eucalyptus oil is a rich source of bioactive compounds with a variety of biological activities and is widely used in traditional medicine. Eucalyptus citriodora is cultivated for the production of essential oils. However, the mode of antibacterial action of essential oils from E. citriodora is not well-known. This study aimed to determine the chemical components, microbial inhibitory effect, and mechanism of action of the essential oil from E. citriodora. The oil was extracted from E. citriodora leaves by hydro-distillation and the chemical components were analyzed using gas chromatography-mass spectrometry. The antibacterial activities of eucalyptus oil against gram-positive bacteria (Bacillus subtilis, Staphylococcus aureus, and Staphylococcus intermedius) and gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) were screened by disc diffusion method and quantitative analysis was conducted by the microdilution method. The mechanism of action of the extracted essential oil was observed using SEM and analyzed by SDS-PAGE. The major components of E. citriodora oil were citronellal (60.55 ± 0.07%), followed by dl-isopulegol (10.57 ± 0.02%) and citronellol (9.04 ± 0.03%). The antibacterial screening indicated that E. citriodora oil exhibited prominent activity against all tested strains. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against B. subtilis were 0.5% and 1.0%, respectively. The MIC and MBC concentrations against S. aureus, S. intermedius, E. coli, and P. aeruginosa were 1% and 2%, respectively. As observed by SEM, the antibacterial mechanism of E. citriodora oil involved cell wall damage; SDS-PAGE revealed decrease in protein bands compared to untreated bacteria. Thus, E. citriodora oil showed significant antimicrobial properties and caused cellular damage.

• Journal of the Korean Wood Science and Technology
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• v.41 no.6
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• pp.497-506
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• 2013

The optimal condition for the torrefaction of eucalyptus (Eucalyptus globulus) was investigated by response surface methodology. The carbon content in the torrefied biomass increased with the severity factor (SF), while hydrogen and oxygen contents decreased. The calorific value of torrefied biomass ranged from 20.23 to 21.29 MJ/kg, depending on the torrefaction conditions. This implied that the energy contained in the torrefied biomass increased by 1.6 to 6.9%, when compared with that of the untreated biomass. The weight loss of biomass increased as the SF increased. The Code level of reaction temperature had the highest impact on the energy yield of torrefied biomass, while the effect of Code level of reaction time was considerably low. The highest energy yield was obtained at low SF.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06a
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• pp.37-42
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• 2006

The paper discusses the combined use of softwood and eucalyptus kraft pulps in the production of printing and writing papers. Looking for process and paper quality optimization, refining pilot plant trails were carried to identify the effects of refining type (mixed or separate) and intensities (specific edge load), and also furnish composition (amount of each pulp in mixture) on final paper quality and process costs. The basic effects on pulp fibers were evaluated against paper quality properties, such as physical strengths, bulk, vessel picking, opacity and porosity, as well as the interactions with papermaking process, such as estimates of paper machine runnability, paper breaks and industrial refining control. The results show that the furnish composition and the type of refining has a significant effect on properties related with both final paper quality and total costs. The best alternative for printing and writing papers was identified for mixed refining, under the lowest refining intensity, and with the highest dosage of eucalyptus pulp.