PROPERTIES AND MORPHOLOGY OF UNSATURATED POLYESTER/ACRYLATE-TERMINATED POLYURETHANE/ORGANO-MONTMORILLONITE NANOCOMPOSITES

Unsaturated polyester resin （UPR）/acrylate-terminated polyurethane （ATPU）/organo-modified montmorillonite （OMMT） nanocomposites were prepared by the in situ intercalative polymerization method. Samples were prepared by the sequential mixing, i.e. mixture of the ATPU and styrene （S） and OMMT were prepared in the first step; UPR was then added to the pre-intercalates of ATPU/S/OMMT. Results indicate that the mechanical properties and thermal properties of UPR/ATPU/OMMT nanocomposites greatly depend on the amount of ATPU and OMMT. Results show that the addition of ATPU could increase the impact strength of UPR/ATPU composites, but the tensile strength, flexural strength and heat resistance of the materials are obviously decreased. When the weight ratio between UPR, ATPU and OMMT were 82：15：3, the impact strength and heat distortion-temperature of nanocomposite were greatly improved, meanwhile there was little change for other properties of the nanocomposites. The synergistic enhancement effects of ATPU and OMMT on the composites were observed. The structures and morphology of the composites were investigated by X-ray diffraction, scanning electron microscopy and transmission electron microscopy.

MiR-214-3p Prevents the Development of Perioperative Neurocognitive Disorders in Elderly Rats

Objective:This study aimed to identify microRNAs(miRNAs)involved in the development of perioperative neurocognitive disorders(PND).Methods:Plasma exosomal miRNA expression was examined in patients before and after cardiopulmonary bypass(CPB)using microarray and qRT-PCR and these patients were diagnosed as PND later.Elderly rats were subjected to CPB,and the cognitive functions were examined.Bioinformatics analysis was conducted to predict the targets of miR-214-3p.Rats were administered rno-miR-214-3p agomir before or after CPB to investigate the role of miR-214-3p in PND development.Results:We identified 76 differentially expressed plasma exosomal miRNAs in PND patients after surgery(P<0.05,|log2FC|>0.58),including the upregulated hsa-miR-214-3p(P=0.002399392).Prostaglandin-endoperoxide synthase 2(PTGS2)was predicted as a miR-214-3p target.In rats,CPB reduced the platform crossing numbers and target quadrant stay time,accompanied with hippocampal neuronal necrosis.The rno-miR-214-3p level was significantly increased in plasma exosomes but decreased in rat hippocampus after surgery,exhibiting a negative correlation(P<0.001,r=-0.762).A negative correlation between miR-214-3p and PTGS2 protein expression was also observed in the hippocampus after surgery.Importantly,rno-miR-214-3p agomir treatment,before or after surgery,significantly increased the platform crossing numbers(P=0.035)and target quadrant stay time(P=0.029)compared with negative control.Hippocampal PTGS2 protein level was increased in the untreated surgery group and decreased in response to rno-miR-214-3p agomir treatment before or after surgery(both P<0.05 vs.negative control).Conclusion:These data suggest that miR-214-3p/PTGS2 signaling contributes to the development of PND,serving as a potential therapeutic target for PND.