• Journal of the Korean Wood Science and Technology
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• v.15 no.3
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• pp.24-33
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• 1987

This study was executed to investigate scanning electron microscopic characteristics of Korean Rhus lacquer coats. With the unrefined coat, distilled water, sodium hydroxide, acetic acid, ethyl alcohol, cold-check test, and accelerated weathering were performed after refining treatment. These treated lacquer coats were discussed through observation by scanning electron microscope and the obtained results were summarized as follows: 1. Compared with unrefined coat, the refined coat of Korean Rhus lacquer showed more even surface with regular distribution of dispression. 2. Korean Rhus lacquer coat heated at $120^{\circ}C$ for 3 hours revealed no observable difference irrespective of refining and unrefining. 3. Korean Rhus lacquer coat treated by distilled water, sodium hydroxide, acetic acid. ethyl alcohol, cold-check test. and ultraviolet radiation showed significant characteristics compared with untreated coat. Especially. large deformation and checkings were observed by cold-check test and ultraviolet radiation respectively. 4. The Korean Rhus lacquer coat radiated by ultraviolet ray showed 0.11 duller and 1.41 brighter than non-radiated coat through color difference calculator.

• Journal of the Korean Wood Science and Technology
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• v.31 no.4
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• pp.81-90
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• 2003

In this study, we investigated the weathering properties of Korean Rhus lacquers containing tung oil and their potential use as exterior coatings. The finished lacquers were prepared with a raw Korean Rhus lacquer or refined Korean Rhus lacquer content of 10, 20, 30 and 40 wt.% (corresponding to ratios of 10/90, 20/80, 30/70 and 40/60 by weight of Korean Rhus lacquer/tung oil, respectively). The curing temperature of the prepared lacquer increased with increasing the content of the raw Korean Rhus lacquer. This increased curing temperature is related to higher proportion of hydroxyl groups in the prepared lacquer, due to the content of the raw Korean Rhus lacquer. In accelerated weathering testing, the changes in the gloss and contact angle of the prepared lacquers showed a similar trend to that of traditional exterior oil stain. In addition, the prepared lacquers containing tung oil showed greater discoloration than traditional exterior oil stain. However, the discoloration of the prepared lacquer with a raw Korean Rhus lacquer content of 40 wt.%, and that of the prepared lacquer with refined Korean Rhus lacquer contents of 30 wt.% and 40 wt.%, showed a similar trend to that of traditional exterior oil stain. Consequentially, these prepared lacquers showed a potential for being used as exterior coatings.

• Korean Journal of Plant Resources
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• v.18 no.2
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• pp.279-284
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• 2005

The study was conducted to investigate the correlation and regression analysis between the factors - diameter, hight and crown width - and collection amount of Rhus lacquer by the sex of Rhus verniciflua. The relationship between the diameter and the collection amount of the lacquer by the sex of the lacquer tree indicated that, for both of the male and the female, the lacquer amount was likely to increase as the diameter got larger. In general, the male trees tended towards the higher amount of the lacquer than the female. The relationship between the crown width and the collection amount of the lacquer by the sex showed little difference. As the crown became wider, however, the lacquer amount showed the increasing trend. The regression analysis by the sex of the tree indicated that the major factors of the female had larger influence on the lacquer amount than those of the male. The no differences of statistical significance were found among the diameter, the height, the crown width, and the lacquer amount.

• Korean Journal of Plant Resources
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• v.21 no.1
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• pp.87-90
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• 2008

The purpose of this experiment is to understand a possibility for the techniques of collecting the Korean Rhus lacquer by the traditional method(Hwachil) against the diminishing lacquer industry. Hwachil method, making use of fire to collect lacquer, is practiced at only some areas, but the lacquer is very efficacious for foods and oriental medicine. A comparative experiment between traditional method and new machine method by processing unit 5 kg of lacquer tree was made to improve Hwachil method technically. The results showed that the machine method produced more about 45% of lacquer than the traditional one. The traditional method, moreover, needed intense labour quality and high leveled techniques, which caused to bring physical sufferings. In comparison with the traditional method for the collecting time required, the machine one showed to take more than minutes per a unit. But the machine method was easy and convenient to handle the machine without special techniques.

• Journal of Pharmacopuncture
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• v.5 no.1 s.8
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• pp.159-169
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• 2002

Objective: It will be examined in this research whether Lacquer poison can be used as an distinguished treatment to cure incurable diseases by considering literature existing and various papers. Method: I studies origin, alias, species, toxicity, effect, treatment, component, medical action and contraindication of Rhus vemiciflua stokes through various kinds literatures. Results: Sap of Rhus vemiciflua stokes that is used for medical purposes, has an effect on anti-tumor, anti-oxidation, hangover cure, and gastritis suppression. Even though urushiol and fIavonoids, the main ingredient of lacquer, has medical cure effects. but urushiol results in a dermatropic allergy. Sincc xylem of a Rhus vemiciflua stokes, however. does not induce the allergy but has medical efficacy, research on this topic is needed.

• Food Science of Animal Resources
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• v.30 no.4
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• pp.597-602
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• 2010

In this study, pigs [n=117; (Landrace ${\times}$ Yorkshire) ${\times}$ Duroc; $64{\pm}0.5$ Kg initial body weight] were used to investigate the effect of feeding different levels of lacquer (Rhus verniciflua Stokes) meal on performance, carcass traits and quality of meat kept under refrigeration at $3{\pm}1^{\circ}C$. The pigs were randomly allotted to 3 treatments on the basis of body weight and sex and each treatment was replicated 3 times (13 pigs in each replicate). Lacquer meal in sawdust form obtained from the stem bark and heartwood of sun-dried lacquer trees was added to the grower and finisher diets at 0, 20 and 40 g/kg diet. The experimental diets were fed for 8 wk. Inclusion of lacquer meal had no influence (p>0.05) on growth performance of pigs. Improvement in carcass traits and decreased back fat thickness were noticed in pigs fed diets added with 20 and 40 g/kg lacquer meal. Longissimus muscle obtained from pigs fed lacquer meal had higher moisture and lower fat content, thiobarbituric acid reactive substances and water holding capacity. Meat from lacquer fed pigs was also darker and redder. The data indicates that lacquer meal can be incorporated up to 40 g/kg in the diet of fattening pigs without affecting growth performance. Also, lacquer meal increases carcass lean content and improves the oxidative stability of the meat.

• Journal of Korean Society of Forest Science
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• v.82 no.2
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• pp.122-127
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• 1993

This study was conducted to investigate characteristics related to lacquer yield and to evaluate possibility of indirect selection of Rhus verniciflua Stokes. Twenty-four lacquer trees were randomly selected for measuring growth, urushiol content and bark thickness. Urushiol content showed a significant positive correlation with outer bark thickness and secretory canal density at 1% level, and with inner bark thickness at 5% level. Bark thickness and secretory canal density could be used as indicators for high urushiol content within bark and thus for high lacquer yield. Mass selection for high lacquer yield was made based on urushiol content within bark. Sixteen individuals with the highest urushiol content value were selected for breeding. As expected, the selected trees had thicker bark, higher density of secretory canal, better developed secretory canals compare to the non-selected lacquer trees.

• Korean Journal of Plant Resources
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• v.10 no.3
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• pp.231-234
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• 1997

Four urushiol components isolated from the sap of Korean lacquer tree(Rhus vernicifera Stokes) showed a strong antifungal activity, but they have no or low activity the bacteria and yeasts. Among them, 3-pentadecylcatechol marked the highest activity on the spore germination of Cladosporium herbarum ($MIC:4{\mu}g/ml$).

• The Korean Journal of Food And Nutrition
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• v.19 no.3
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• pp.267-270
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• 2006

In Korea, for a long time Rhus verniciflua has traditionally been used as an herbal medicines plants. A stem of Rhus verniciflua has been used to treat gastrointestinal trouble with in form of boiled chicken as a folk medicine. But it has been recognized as an extremely active allergen causing skin reactions. The chief allergenic component, urushiol, is found within the oleoresinous sap of Rhus verniciflua. Most components of urushiol have unsaturated side chains. These unsaturated side chains of urushiol are important to polymerization of these natural products. The urushiol components in Korean lacquer were isolated by reversed phase HPLC. The molecular weight of purified urushiol was determined as 340 from mass analysis. This compound was identified as Heptadecatetraenyl catechol (MW 340).

• Korean Journal of Plant Resources
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• v.11 no.1
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• pp.40-46
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• 1998

For the comparison of the urushiol composition and biological acitivity between the fresh sap and fire distilled sap of lacquer tree(Rhus vernicifera), we analysed the urushiol composition by HPLC and EI-MS, and investigated the antioxidative , antimicrobial and anticancer acitivities according to solvent fractionations. There was no difference in the urushiol composition between fresh and fire distilled saps of lacquer tree. The hexane frqctionsof two saps showed a strong DPPH radical scaverging activity (RC50 : 7.0-7.5$\mu\textrm{g}$). They also showed a strong antifungal activity onthe spore germination of Cladosporium herbarum(MIC : 8$\mu\textrm{g}$/ml), whereas they have no or low activity against the bacteria(BAcillus subtilis , Escherichia coli). In addition , hexane and butanol fractions of two saps showed a strong inhibitory activity against cultured tumour cell lines (GI50 : 0.35, 12.29$\mu\textrm{g}$/ml) in vitro. These results confirm that the fresh sap and fire distilled sap might have the similar urushiol compositions and biological activities.