Polymer blends of polybenzoxazine (PBA-a) and polycaprolactone (PCL) of different molecular weights (M n 5 10,000, 45,000, and 80,000 Da) were prepared at various PBA-a/PCL mass ratios and their properties were characterized. The results from dynamic mechanical analyzer (DMA) revealed two glass transition temperatures implying phase separation of the two polymers in the studied range of the PCL contents. Moreover, a synergistic behavior in glass transition temperature (T g ) was evidently observed in these blends with a maximum T g value of 281 C compared with the T g value of 169 C of the PBA-a and about 250 C of the PCL used. The blends with higher M n of PCL tended to provide greater T g value than those with lower M n of PCL. The modulus and hardness values of PBA-a were decreased while the elongation at break and area under the stress2strain curve were increased with an increase of the content and M n of PCL, suggesting an enhancement of toughness of the PBA-a. Scanning electron micrographs (SEM) of the sample fracture surface are also used to confirm the improvement in toughness of the blends. V C 2015 Wiley Periodicals, Inc. J.Appl. Polym. Sci. 2015, 132, 41915.
Gray oyster mushroom, a common edible mushroom in Thailand, has been used as a source for polysaccharide extraction and purification. In this study, we extracted polysaccharides from the gray oyster mushroom through hot water, ammonium oxalate, and alkaline extraction methods. The extracts were further purified using enzymatic digestion, solvent extraction, and column chromatography. Fourier‐transform infrared spectroscopy reveals that the selected fractions contain β‐(1→3) glucan and mannan. Monosaccharide composition analysis suggests that glucose and mannose are the major constituents of all analyzed fractions. Interestingly, only the gel‐like fraction, namely SG1‐1 could enhance neutrophils’ killing activity on Candida albicans. In addition, the purified fractions stimulated glucose uptake activity in the L6 myotubes in a dose‐dependent manner.
Practical applications
The ability of those polysaccharides to stimulate glucose uptake in the muscle cells and enhance a neutrophil’s killing activity implicates the antidiabetic and immunostimulatory activities, respectively. Thus, these polysaccharides could be potentially developed into an immunostimulating agent and an alternative medicine for treating diabetes mellitus.
Functional mushroom polysaccharides have been known to the Asian traditional medicine for many years. The antiobesity activity of mushroom polysaccharides has been illustrated both in vivo and in vitro. However, the effect of pure polysaccharides on isolated fat cells has not been demonstrated. In this study, we used hot water and ammonium oxalate to extract polysaccharides from gray oyster mushroom [Pleurotus sajor-caju (Fr.) Sing.] and subsequently purified with enzymatic digestion, solvent extraction and ion-exchange chromatography. One of the fractions, 7S1-1, has the highest yield and purity and contains polysaccharides with the molecular weight around 500 kDa. In addition, Fourier transformed infrared spectroscopy (FTIR) and monosaccharide composition analyses showed that this 7S1-1 sample contains mostly β-glucan and some mannan. We find that the 7S1-1 fraction does not affect the total amount of triglycerides in the 3T3-L1 adipocytes but promotes a release of glycerol of the fat cells, suggesting that the fraction does not inhibit adipogenesis but stimulates lipolysis. Laminarin, a small β-glucan, confers similar results to the 7S1-1 sample, but it could not stimulate lipolysis as well as the 7S1-1 sample. Therefore, these results suggest a potential antiobesity activity of the mushroom polysaccharides.
We present the fabrication of graphene oxide (GO) and manganese dioxide (MnO 2 ) composite fibers via wet spinning processes, which entails the effects of MnO 2 micromorphology and mass loading on the extrudability of GO/MnO 2 spinning dope and on the properties of resulted composite fibers. Various sizes of rod and sea-urchin shaped MnO 2 microparticles have been synthesized via hydrothermal reactions with different oxidants and hydrothermal conditions. Both the microparticle morphology and mass loading significantly affect the extrudability of the GO/MnO 2 mixture. In addition, the orientation of MnO 2 microparticles within the fibers is largely affected by their microscopic surface areas. The composite fibers have been made electrically conductive via chemical or thermal treatments and then applied as fiber cathodes in Zn-ion battery prototypes. Thermal annealing under an argon atmosphere turns out to be an appropriate method to avoid MnO 2 dissolution and leaching, which have been observed in the chemical treatments. These rGO/MnO 2 fiber cathodes have been assembled into prototype Zn-ion batteries with Zn wire as the anode and xanthan-gum gel containing ZnSO 4 and MnSO 4 salts as the electrolyte. The resulted electrochemical output depends on the annealing temperature and MnO 2 distribution within the fiber cathodes, while the best performer shows stable cycling stability at a maximum capacity of ca. 80 mA h/g.
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