Impact of wetting and drying cycle treatment of intumescent coatings on the fire performance of thin painted red lauan (Parashorea sp.) plywood

Emulsion resins are widely used in wood-based materials for indoor furnishings. Previous studies have demonstrated that the ability of a material to retard flame arises from the interactions between four major components: i.e., binder resin (BR); carbonizing substrate (CS); foam-producing substance (FPS); and dehydrating agent (DA). Fire performance as influenced by wetting and drying cycle (WDC) treatment has not yet been reported. This study aimed to compare the fire performance of materials coated with EVAc (ethylene vinyl acetate copolymer) and PVAc (polyvinyl acetate copolymer) emulsion resins of differing BR/CS ratios, subjected to investigation by cone calorimeter. Intumescent formulation significantly enhanced the fire retardancy of painted plywood by exhibiting lower peak heat release rates (PHRR) and longer time to reach peak release rates. Additionally, lower BR content in the fire retardant systems further enhanced flame retardancy. The fire retardancy decreases with increasing the WDC treatment, caused by the weight loss of the coating materials. Infrared (FT-IR) analysis demonstrated that lower BR content extends the survival duration of the phosphorcarbonaceous structure of chars. The findings in this study enhance the state-of-the-art understanding of the effect of the intumescent.     

Schisandrin B co-treatment ameliorates the impairment on mitochondrial antioxidant status in various tissues of long-term ethanol treated rats

The effect of schisandrin B (Sch B) on long-term ethanol-induced oxidative stress in various rat tissues was investigated. Long-term ethanol treatment increased reactive oxygen metabolites (ROM) level in plasma. The ethanol-induced oxidative stress was assessed by mitochondrial glutathione and α-tocopherol levels, antioxidant enzyme activities, malondialdehyde (mtMDA) production and heat shock protein (Hsp) 25/70 levels. Liver was most susceptible to oxidative stress with a significant increase in mtMDA production. Long-term Sch B treatment enhanced mitochondrial antioxidant status in a tissue non-specific manner. Sch B co-treatment ameliorated the alterations in plasma ROM levels, mtMDA production and Hsp 25/70 expression in rat tissues.     

Isolation, structure characterization, and immunomodulating activity of a hyperbranched polysaccharide from the fruiting bodies of Ganoderma sinense

A polysaccharide (GSP-6B) with a molecular mass of 1.86 × 10? Da was isolated from the fruiting bodies of Ganoderma sinense . Chemical composition analysis, methylation analysis, infrared spectroscopy, and nuclear magnetic resonance spectroscopy were conducted to elucidate its structure. GSP-6B contains a backbone of (1→6)-linked-β-D-glucopyranosyl residues, bearing branches at the O-3 position of every two sugar residues along the backbone. The side chains contain (1→4)-linked-β-D-glucopyranosyl residues, (1→3)-linked-β-D-glucopyranosyl residues, and nonreducing end β-D-glucopyranosyl residues. An in vitro immunomodulating activity assay revealed that GSP-6B could significantly induce the release of IL-1β and TNF-α in human peripheral blood mononuclear cell (PBMC) and showed no toxicity to either PBMC or a human macrophage cell line THP-1. GSP-6B could also activate dendritic cells (DC) by stimulating the secretion of IL-12 and IL-10 from DC.     

A molecular dynamics simulation on the self-assembly of ABC triblock copolymers. 3. Effects of block composition in asymmetric triblock copolymers

The self-assembly of asymmetric ABC triblock copolymers in the ordered structure is investigated using an isothermal-isobaric molecular dynamics simulation. Unlike symmetric ABC triblock copolymers, more fascinating morphologies are observed in asymmetric ones because of a larger difference of incompatibility between the components. Various modes of self-assembly in assymmetric ABC triblock copolymers are also observed depending on the block composition. When the composition of block A is changed from 0.125 to 0.25 at the samef _B =0.25, the morphological transition from the “cylinder in cylinder” to “cylinders at cylinder” structure is observed in the simulation. In the case of ABC triblocks withf _B =0.5, a lamellar-type structure is changed to a cylinder-type structure with increasing the length of block A. When the mid-block length increases further tof _B =0.625, the “spheres on cylinder” structure is observed in both the A₁₀B₅₀C₂₀ and A₂₀B₅₀C₁₀ triblocks. From these results, the phase diagram of ABC triblock copolymers can be constructed. Dedicated to Professor Won-Jei Cho on the occasion of his retirement.     

Phytochemical composition of onion during long-term storage

Onion cultivar “Sunpower” has growing popularity in Korea due to high storability. The present study considers changes in flavonols, sugars, and two amino acids in onion bulbs during a long-term storage in the ambient dark storage room and in glasshouse equipped with a climate control system. Flavonol and sugar contents were found to fluctuate noticeably during the storage period. Amino acid content remained relatively unchanged till the onset of inner sprouting, increasing afterward. Visible sprouts appeared at week 22 in the dark storage room and for four weeks later in the glasshouse. The bulbs lost 20–30% of their weight depending on storage conditions at the end of the storage trials. At the same time, the content of nutraceutics in study expressed on the dry weight basis remained of the same order of magnitude. The nature of observed variations in chemical composition of onions as well as relation of this phenomenon to physiological development of stored onion bulbs is discussed. A conclusion is made that the “Sunpower” onion cannot sustain overwinter storage.     

Durable press finish of cotton via dual curing using UV light and heat

Continuous photografting/crosslinking of polyethyleneglycol dimethacrylate oligomers onto cotton using a water-soluble benzophenone photoinitiator was investigated. Photografting increased with increasing irradiation dose, oligomer concentration and photoinitiator concentration. Maximum grafting efficiency of DM 400 and 600 were 83% and 79%, respectively. The photografting increased the wrinkle resistance of cotton implying surface crosslinking of cotton. Both surface crosslinking and bulk crosslinking of cotton were accomplished via dual curing of a mixed formulation containing both a thermally curable component (BTCA/SHP) and a UV-curable component. The wrinkle resistance of the crosslinked cotton was found to be higher when cured by thermal curing after UV curing rather than by UV curing after thermal curing due to the facile post-polymerization of the UV active component. The presence of crosslinks in the dually crosslinked cotton was verified with FT-IR and thermogravimetric analysis.     

New Benzoxazine Secondary Metabolites from an Arctic Actinomycete

Two new secondary metabolites, arcticoside (1) and C-1027 chromophore-V (2), were isolated along with C-1027 chromophore-III and fijiolides A and B (3–5) from a culture of an Arctic marine actinomycete Streptomyces strain. The chemical structures of 1 and 2 were elucidated through NMR, mass, UV, and IR spectroscopy. The hexose moieties in 1 were determined to be d-glucose from a combination of acid hydrolysis, derivatization, and gas chromatographic analyses. Arcticoside (1) and C-1027 chromophore-V (2), which have a benzoxazine ring, inhibited Candida albicans isocitrate lyase. Chromophore-V (2) exhibited significant cytotoxicity against breast carcinoma MDA-MB231 cells and colorectal carcinoma cells (line HCT-116), with IC₅₀ values of 0.9 and 2.7 μM, respectively.