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31.
Unsaturated polyester resin synthesized from glycolyzed product of polyethylene terephthalate (PET) waste was used as a matrix to form coconut fiber/polyester composites. PET wastes were recycled through glycolysis and polyesterification reaction to produce a formulation for unsaturated polyester resin (UPR). FTIR spectra of glycolyzed product and prepared resin revealed that cross-links between unsaturated polyester chain and styrene monomer occurred at the saturated sites which resulted in the forming of cross linking network. To improve the adhesion between coconut fiber and polyester resin, various concentrations of alkali, silane and silane on alkalized fiber were applied and the optimum concentration of treatments was determined. The influence of water uptake on the sorption characteristics of composites was studied via immersion in distilled water at room temperature. Surface treatment of coconut fiber caused a significant increase in the tensile properties with the optimum treatment is 0.5 % silane on the 5 % alkalized coconut fiber/polyester composites. It was also observed that the treated fiber composites showed lower water absorption properties in comparison to those of untreated fiber composites. This observation was well supported by the SEM investigations of the fracture surfaces. From the study, it was concluded that polyester reinforced coconut fiber composites derived from recycling polyethylene terephthalate (PET) waste may have the potential application in the fields of construction and automotive interior substrates. 相似文献
32.
Syarifin Firdaus Adriaan W. van Heusden Nurul Hidayati Ence Darmo Jaya Supena Richard G. F. Visser Ben Vosman 《Euphytica》2012,187(1):31-45
Bemisia tabaci is one of the most threatening pests in agriculture, particularly in Solanaceous crops such as tomato and pepper that are cultivated in the open field. Pesticide application is often not effective and hazardous to humans and environment. The exploitation of plant natural defenses that are present in wild relatives of tomato, may offer a solution. To evaluate resistance parameters and to identify plant material with high levels of resistance, we screened a number of accessions of tomato wild relatives using three methods; a free-choice test in a screenhouse in Indonesia, a no-choice test with clip-on cages in a greenhouse and a leaf disc test in a climate-room in the Netherlands. Antibiosis resulting in low adult survival was the major component for resistance in tomato. However, other resistance component(s) may play a role as well. In some accessions there was a change in the resistance level over time. Several resistance parameters used in the different tests were well correlated. The best resistance source was an accession of Solanum galapagense, which had not been identified as being resistant in the past. This is of particular interest as this species is closely related to the cultivated tomato, which may facilitate introgression of the resistance component(s). Whitefly non-preference and resistance were associated with the presence of type IV trichomes. Other mechanisms might be involved since some accessions without type IV trichomes showed low nymphal density. The leaf disc test is a good in vitro alternative for the clip-on cage whitefly resistance screening, as shown by the high correlation between the results obtained with this test and the clip-on cage test. This offers breeders the possibility to carry out tests more efficiently. 相似文献
33.
Hyun Ah Jung Md. Nurul Islam Chan Mee Lee Hyong Oh Jeong Hae Young Chung Hee Chul Woo Jae Sue Choi 《Fisheries Science》2012,78(6):1321-1329
In the present study, we investigated the antidiabetic potential of fucoxanthin via the inhibition of rat lens aldose reductase (RLAR), human recombinant aldose reductase (HRAR), advanced glycation end-product (AGE) formation, protein tyrosine phosphatase 1B (PTP1B), and α-glucosidase. Fucoxanthin displayed potent inhibitory activity against AGE formation and HRAR and RLAR activity. In addition, fucoxanthin showed potent inhibitory activity against PTP1B. However, it did not show α-glucosidase inhibitory activity below 200 μM. In addition, our kinetic study revealed that fucoxanthin competitively inhibited RLAR, while it showed mixed-type inhibition against PTP1B. In order to confirm enzyme inhibition, we predicted the 3D structure of PTP1B using Autodock 4.0 to simulate the binding of fucoxanthin. Docking simulation results demonstrated that three residues of PTP1B (Phe30, Phe52, and Gly183) interact with the two hydroxyl groups of fucoxanthin. In addition, the binding energy was negative (?7.66 kcal/mol), indicating that the three hydrogen bonds may stabilize the open form of the enzyme and potentiate tighter binding to the active site of PTP1B, resulting in more effective PTP1B inhibition. The results of the present study therefore clearly demonstrate the promising potential of fucoxanthin as a therapeutic intervention for the management of diabetes as well as diabetes-associated complications, which could be explored further. 相似文献
34.
Production trials of threatened snakehead fish (Channa striatus) were carried out under different stocking densities in earthen ponds of Bangladesh. The average weight and length of the fingerlings during stocking was 17.63 ± 1.23 g and 13.21 ± 0.52 cm. Fingerlings were stocked at 5000 ha?1 in treatment‐1 (T1), 6250 ha?1 in treatment‐2 (T2) and 7500 ha?1 in treatment‐3 (T3) respectively. Fish in all the experimental ponds were fed with supplementary feed comprising of fish meal (30%) and mustard oilcake (70%) at the rate of 3–6% of estimated body weight two times per day. In addition, trash fish were supplied at the rate of 2–3% of the estimated biomass on each alternate day. In situ water quality parameters of the pond were within the suitable range for fish culture. The growth and survival of fingerlings were significantly higher in T1 than in T2 and T3. The food conversion ratio was significantly lower (P<0.05) in T1 than in T2 and T3. The estimated gross and net production of fish was higher in T1, followed by T2 and T3. Overall, the highest growth, survival and production were obtained from T1. Therefore, it could be concluded that of 5000 fingerlings ha?1 is the most suitable stocking density for culturing C. striatus under a monoculture system in the earthen ponds for better production. 相似文献
35.
A. Nurul Huda M. R. Che Salmah A. Abu Hassan A. Hamdan M. N. Abdul Razak 《Journal of insect science (Online)》2015,15(1)
Measuring wild pollinator services in agricultural production is very important in the context of sustainable management. In this study, we estimated the contribution of native pollinators to mango fruit set production of two mango cultivars Mangifera indica (L). cv. ‘Sala’ and ‘Chok Anan’. Visitation rates of pollinators on mango flowers and number of pollen grains adhering to their bodies determined pollinator efficiency for reproductive success of the crop. Chok Anan failed to produce any fruit set in the absence of pollinators. In natural condition, we found that Sala produced 4.8% fruit set per hermaphrodite flower while Chok Anan produced 3.1% per flower. Hand pollination tremendously increased fruit set of naturally pollinated flower for Sala (>100%), but only 33% for Chok Anan. Pollinator contribution to mango fruit set was estimated at 53% of total fruit set production. Our results highlighted the importance of insect pollinations in mango production. Large size flies Eristalinus spp. and Chrysomya spp. were found to be effective pollen carriers and visited more mango flowers compared with other flower visitors. 相似文献
36.
The endangered tropical tree, Aquilaria malaccensis, produces agarwood for use in fragrance and medicines. Efforts are currently underway to produce valuable agarwood compoundsn tissue culture. The purpose of this study was to develop an optimal growth medium, specifically, the best hormone combination for callus suspension culture. Using nursery-grown A. malaccensis, sterilized leaf explants were first incubated on basic Murashige and Skoog(MS) gel medium containing 15g/L sucrose and at pH 5.7. Different auxin types including 1-naphthaleneacetic acid(NAA), 2,4-dichlorophenoxyacetic acid(2,4-D), and indole-3-butyric acid(IBA), were tested at various concentrations(0.55, 1.1 and 1.65 μM) using the basic medium. Leaf explants were incubated for 30 days in the dark. Callus induced by 1.1 μM NAA had the highest biomass dry weight(DW) of 17.3 mg; however the callus was of a compact type. This auxin concentration was then combined with either 6-benzylaminopurine(BAP) or kinetin at 0.55, 1.1, 2.2 or 3.3 μM to induce growth of friable callus. The 1.1μM NAA + 2.2μM BAP combination produced friable callus with the highest biomass(93.3mg DW). When testing the different carbon sources and pHs, sucrose at 15g/L and pH at 5.7 yielded highest biomasses at 87.7mg and 83 mg DW, respectively. Microscopic observations revealed the arrangement of the friable cells as loosely packed with relatively large cells, while for the compact callus, the cells were small and densely packed. We concluded that MS medium containing 15 g/L sucrose, 1.1 μM NAA + 2.2 μM BAP hormone combination, and a pH of 5.7 was highly effective for inducing friable callus from leaf explants of A. malaccensis for the purpose of establishing cell suspension culture. 相似文献