Flame retarding PC/ABS resins having superior thermomechanical properties

Triphenyl phosphate (TPP) is well known to be one of the most effective flame retardants for acrylonitrile-butadiene-styrene copolymer (ABS) and its blending resins, such as polycarbonate (PC)/ABS, among various phosphorous-based compounds. However, TPP can also play a role as a plasticizer, which decreases the mechanical properties of PC/ABS resins at high temperature. Furthermore considerable amount of TPP has to be evaporated during molding process due on its much lower evaporation temperature. To overcome these shortcomings, we tried to immobilize TPP by grafting on butadiene moiety of ABS. FT-IR analysis of prepared TPP-grafted ABS (ABS-g-TPP) comparing with TPP, ABS and their blend confirmed that chemical reactions happened between TPP and ABS resins and it was attributed to the graft reaction of TPP onto butadiene moieties. Prepared ABS-g-TPP resins were blended with PC at various compositions to be prepared as testing specimens by injection molding. The physical characteristics such as mechanical properties, thermal stability, and flame retarding properties of the PC/ABS-TPP graft copolymer were analyzed through Vicat softening temperature, IZOD impact strength, transmission electron microscope, and UL94 flame retardation tests. Results showed that PC/ABS-g-TPP resin takes better thermomechanical properties than the existing PC/ABS resins at relatively low additional TPP amounts.     

Starch properties of native foxtail millet, Setaria italica Beauv.

Properties of foxtail millet (Setaria italica Beauv.) starches have been studied. Amylose content ranged between 3.3 and 11.4%. Starch content was from 67.5 to 68.7%. The onset temperature (To) of all samples ranged from 66.4 to 69.6°C, peak temperature (Tp) ranged 71.0 to 74.2°C, and their gelatinization enthalpy varied from 0.44 to 8.22 J/g, respectively. A highest gelatinization temperature was obtained for Bongseongjaerae (69.6°C). The enthalpy of the gelatinization (Δ H _gel ) was highest in Andongjaerae. The highest peak, highest breakdown, very high final viscosity, and very low setback were noted in Jucheonjaerae. The starch granule sizes ranged 10.1–25.0 in length and 4.7–12.5μm in diameter. X-ray diffraction angles indicated that all starch samples possess a typical A-type crystallinity.     

Effect of silicon on growth and salinity stress of soybean plant grown under hydroponic system

Silicon (Si) is abundant in the soil, yet its role in plant biology has been poorly understood. The role of Si in soybean growth and its effectiveness in salt stress alleviation was investigated. Sodium metasilicate (Na₂SiO₃) was given as Si source to hydroponically grown soybean (Glycine max (L.) Merr.). The plant growth attributes, i.e. plant height, plant fresh and dry biomass, chlorophyll contents and endogenous gibberellins (GAs) level improved with 2.5 mM Si, while endogenous abscisic acid (ABA) and free proline contents were not affected as compared to control. Sodium chloride (NaCl) significantly decreased growth attributes and endogenous gibberellins levels but markedly enhanced ABA and proline contents of soybean leaves. An addition of Si to salt stressed plants substantially alleviated the adverse effects of NaCl on growth, as it enhanced endogenous gibberellins, while reduced the levels of ABA and proline. GAs analysis of soybean leaves also showed that both early C13 hydroxylation and non C13 hydroxylation pathways of gibberellin biosynthesis were operating in soybean. The major GA biosynthesis pathway was identified as non C13 hydroxylation, which led to the formation of bioactive GA₄. Current study suggests that Si application alleviates the detrimental effect of salinity stress on growth and development of soybean.     

Aroma finishing of PET fabrics with PVAc nanoparticles containing lavender oil

A durable aroma finishing for PET fabric was carried out by adopting poly(vinyl acetate) (PVAc) nanoparticles containing lavender oil (LO) in core. Relatively small size of PVAc nanoparticles (ca. 244 nm of mean particle diameter) was expected to resist the frictional destruction of the particles, which is frequently observed in cases of microcapsules. PVAc nanoparticles containing LO in core were prepared by emulsification-diffusion method and their application as an aroma releasing agent for PET fabrics was assessed through the observation of releasing profiles of LO in ethanol for experimental acceleration. Melamine-formaldehyde (MF) microcapsules containing LO were also prepared and treated on fabrics for comparison. PVAc nanoparticles treated on PET fabric showed higher initial releasing amount, which was ascribed to the enhanced surface area. After 2 days of releasing, PET fabric treated with PVAc nanoparticles showed slower and more stable releasing profile and reached about 12 ppm of cumulative release after 16 days, which was under two thirds of that with MF microcapsules. PVAc nanoparticles can be used as an agent for durable aroma finishing of PET fabrics.     

Production of a novel 9,12-dihydroxy-10(E)-eicosenoic acid from eicosenoic acid by Pseudomonas aeruginosa PR3

Microbial conversions of unsaturated fatty acids often generate polyhydroxy fatty acids, giving them new properties such as higher viscosity and reactivity. A bacterial strain Pseudomonas aeruginosa (PR3) has been intensively studied to produce mono-, di-, and trihydroxy fatty acids from different 9-cis-monoenoic fatty acids such as oleic acid, ricinoleic acid, and palmitoleic acid. However, from the results and the postulated similar metabolic pathways involved in these transformations, it was assumed that the enzyme system involved in transformation of the monoenoic fatty acid by strain PR3 could utilize fatty acids with different chain lengths and locations of the double bond. In this study was used as a substrate for bioconversion by strain PR3 eicosenoic acid (C20:1, ω-9) containing a singular cis double bond at different positions from the carboxyl end as oleic acid, and it was confirmed that PR3 could produce a novel 9,12-dihydroxy-10(E)-eicosenoic acid (DED) with 6.2% yield from eicosenoic acid. The structure of DED was confirmed using GC-MS, FTIR, and NMR analyses. DED production was maximized at 72 h after the substrate was added to the 24 h culture. Some other nutritional factors were also studied for optimal production of DED.     

Development of a polymerase chain reaction (PCR) procedure for the detection of baculovirus associated with white spot syndrome (WSBV) in penaeid shrimp

The causative viral agent was purified from diseased shrimp Penaeus japonicus with white spot syndrome (WSBV). Several hundred clones were obtained from libraries of the purified viral genomic DNA. According to the results of nucleotide sequence analysis, none of the WSBV clones showed considerable sequence homology with those of other known viruses, indicating that WSBV is a new virus causing a serious disease in shrimp. Based on the sequence data of WSBV genomic DNA, a pair of polymerase chain reaction (PCR) primers was designed. After 30 cycles of PCR amplification of viral genomic DNA extracted from WSBV, a single product of the expected size was detected. Southern blot hybridization confirmed that the amplified product was specific to the DNA of WSBV. The PCR system was able to detect 1 pg of WSBV DNA after 30 cycles, and efficiently amplify the target region of WSBV gene in the total nucleic acids extracted either from the diseased shrimp or hatchery shrimp with no signs of viral infection.     

Molecular cloning of vitellogenin cDNA in rockfish (Sebastes schlegeli) and effects of estrogenic substances on its gene expression

In this study, we have cloned a partial cDNA of 620 bases encoding a vitellogenin gene of rockfish (rfVTG), Sebastes schlegeli. The expression levels of rfVTG mRNA increased 48 h after the 4-nonylphenol (NP) treatment (10 mg/kg BW) in both sexes. On the other hand, the mRNA levels of rfVTG increased 48 h in males and 12 h in females after injection when higher dose (25 mg/kg BW) of 4-NP was applied. It suggested that 4-NP induced VTG gene expression in both male and female immature rockfish. Therefore, the cloned rfVTG cDNA in this study can be used as a tool for monitoring endocrine disruptors in rockfish.