Both poly(lactic acid) (PLA) and poly(ethylene glycol) (PEG) are biodegradable polymers, blending PLA with PEG is expected to toughen PLA matrix while maintaining its biodegradability. In this study, PLA/PEG blends in different ratios were prepared through triple-screw extruder, and the foaming behavior was investigated using supercritical carbon dioxide as physical blowing agent. The mechanical, thermal, rheological properties, and crystallization behavior were also studied. By the incorporation of PEG, the impact strength of the PLA/PEG blends improved by 98% with the specimens fractured in a ductile mode. The crystallization process of the blends was accelerated, and the crystallinity was significantly increased to 45.1%. The viscoelasticity of the PLA/PEG matrix was weakened, and the cells tended to break at the cell wall during cell expansion; thus, a highly interconnected structure with a maximum porosity of 82.3% was obtained. Moreover, the PLA/PEG blends exhibited higher cell densities and smaller cell size, compared to their neat counterparts.
The green tea polyphenol (-)-epigallocatechin-3-gallate (EGCG) was investigated for its enhancement effect of huperzine A on inhibiting acetylcholinesterase (AChE). The inhibitory effect of huperzine A on acetylcholinesterase is quite weak in the whole phase. EGCG hardly inhibits the AChE activity within the range 10-300 mg/kg. However, upon addition of EGCG to the huperzine A groups, a remarkably enhanced inhibitory effect was observed. The EGCG also can largely prolong the inhibitory time. These results indicate that addition of EGCG to huperzine A can reduce the dose of huperzine A required compared with huperzine A alone. The enhancement and complementary effect of EGCG on huperzine A activity may partly be due to the antioxidant property of EGCG. One of the beneficial effects of green tea is to induce a feeling of relief. It is conceivable that this function may be regulated by EGCG in the central nervous system since EGCG is distributed in the brain after oral administration. EGCG can be used as an enhanced supplement for huperzine A to treat Alzheimer's disease.
Liquid menisci at millimeter length scales and smaller exhibit large Laplace pressures. To utilise these effects, liquid ring bearings have recently been developed, which consist of liquid rings confined between alternate superhydrophobic and hydrophilic patterns. We present a detailed experimental and theoretical performance analysis of such bearings. For a single, 100 μm thickness, liquid ring, the maximum supporting force is 0.13 N, which decreases with increasing the ring misalignment. The frictional torque increases linearly with rotational speed until a critical Reynolds number is reached. Above this, an instability occurs due the concave liquid ring meniscus, which further increases friction. These results show how liquid ring bearings can be optimised. Nomenclature radius of the bearing height of the gap width of the hydrophilic strip upper limit of
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