Due to the increase of oil price and the environmental issue such as the emission of volatile organic compounds, the necessity for developing alternative resins of petroleum-based adhesive resins, which have extensively been used for the manufacture of wood-based products, has been speculation since the early 1990. In our study, rapeseed flour (RSF), which is the by-product of bio-diesel produced from rapeseed, were hydrolyzed by enzymes. As a crosslinking agents of the RSF hydrolyzates, phenol-formaldehyde prepolymers (PF) were prepared. The RSF hydrolyzates and PF were mixed to complete the formulation of RSF-based adhesive resins, and the resins were applied to make the laminated veneer lumber (LVL). The physical and mechanical properties of the LVL were measured to examine whether RSF can be used as raw materials of adhesive resins for the fabrication of LVL or not. The average moisture content and soaking delamination rate of the LVL bonded with RSF-based adhesive resins exceeded the minimum requirement of KS standard. Moreover, thermal analysis of the RSF-based resins showed similar tendencies except for the RSF-based adhesive resins formulated with pectinase-hydrolyzed RSF. The bending strengths of the LVL were higher than that of the LVL made with commercial PF resins. These results showed the potential of RSF as a raw material of alternative adhesives for the production of LVL. Further works on the optimal conditions of RSF hydrolysis and spreading characteristics for RSF-based adhesive resins is required to improve the adhesive performance of RSF-based resins.
In this study, based on the antioxidative effects in organic solvent fractions obtained from the main methanolic extract of L. japonica, the protective cellular effects and gene expression patterns of ethyl acetate fractions on H2O2-induced Raw 264.7 cell death (IC50) were analyzed. The antioxidant activity of the fractions measured using DPPH free radical scavenging activity increased in a dose-dependent manner, and the ED50 exhibited the highest 39.56 μg/ml in the ethyl acetate fraction. In addition, the ethyl acetate fractions' cell viability on H2O2-induced Raw 264.7 cell damage increased in a concentration-dependent manner, showed a visible cell survival rate of 82.49% at a concentration of 100 μg/ ml. The gene expression patterns related to the ethyl acetate fractions' cytoprotective effect in H2O2-induced Raw 264.7 cell damage presented similar patterns to those of BHA. In comparative analysis for antioxidant activity-related genes affected by ethyl acetate fractions and BHA in H2O2-induced Raw 264.7 cells, both ethyl acetate fractions and BHA showed very similar gene expression patterns, but the gene expression level of the heme oxygenase 1 (Hmox1) gene making antioxidant enzymes in cells was four times higher in ethyl acetate fractions than BHA. In inflammation-related genes in H2O2induced Raw 264.7 cells, the T-box transcription factor (Tbx21) gene was expressed about two times more frequently in the ethyl acetate fraction treatment group, while it was expressed half as frequently in the BHA treatment group.Key words : Lonicera japonica, antioxidant activity, inflammation, gene expression *Corresponding author *Tel : +82-41-540-9595, Fax : +82-41-548-6231 *E-mail : isbang@hoseo.edu This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
In the present study, rapeseed flour (RSF), which is a by-product from the production of edible oil and biodiesel extracted from rapeseed, was used to develop alternative adhesives for the production of plywood panels. To examine the effects of the enzyme on the adhesive properties and formaldehyde emission of the RSF-based adhesive resins, three enzymes, such as cellulase (CEL), pectinase (PEC) and protease (ALC), were used either separately or together. As a crosslinking agent, PF prepolymers, which were prepared with 1.5, 1.8 and 2.1 mole formaldehyde and 1 mol phenol (1.8-, 2.1-and 2.4-PF), were added into the RSF hydrolyzates. The adhesive resins formulated with CEL-or CEL-PEC-RSF hydrolyzates and 1.8-F/P PF prepolymers exhibited excellent adhesive strengths and formaldehyde emission. The tensile shear strength and formaldehyde emission of the plywood panels bonded with the formulate resins were satisfied with the minimum requirement of the KS standard for ordinary plywood panels (0.6 N/mm 2 ). In addition, formaldehyde emissions of the plywood panels approached to that of E0 specified in the KS standard (0.5 mg/ℓ), and even had much better than those of commercial UF glue mixes. Overall, the use of RSF-based adhesive resins for the production of plywood panels might provide durable adhesive properties and an environmentally friendly substitute for petroleum-based adhesive resins. However, further researches -the increase of solid content of RSF-based adhesives for reducing press time and the microscopic observation of plywood specimen for identifying the relationship between tensile shear strength and the penetration of adhesives into wood structure -are required to commercialize the RSF-based adhesives.
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