具有绿色降解自修复特性的苯氧树脂及其复合材料的制备

以苯硼酸(PBA)作为苯氧树脂(PO)的固化剂,采用一步法合成了一种含有可逆硼酸酯键(B—O—C)的新型苯氧树脂(POPBA30),并制备了碳纤维增强复合材料(CFRPs)。探讨了POPBA30树脂的固化过程和热性能,以及CFRPs的力学性能、热力学性能、降解性能、自修复性能及耐溶剂性能。利用红外光谱对PO、POPBA30、再生苯氧树脂(R-PO)和再生苯硼酸(R-PBA)进行了结构表征。通过差示扫描量热分析测得POPBA30的T_(g)高达206℃,热重分析测得POPBA30在空气和氮气气氛中的T_(d5)分别为411℃和399℃,800℃的质量保留率均高于38%;POPBA30还具有良好的耐化学性,可以在常见的溶剂中稳定存在21 d。以POPBA30为基体制备复合材料(CF/POPBA30),通过万能试验机测得其弯曲强度、层间剪切强度和抗张强度分别为975 MPa,55MPa和734 MPa。CF/POPBA30还具有优异的自修复性能,自修复效率约为85.6%。此外,CF/POPBA30可在室温下99%的乙醇水溶液中发生绿色降解,并实现对碳纤维和苯氧树脂的回收。

Mitochondrial sensitive probe with aggregation-induced emission characteristics for early brain diagnosis of Parkinson’s disease

The early diagnosis of Parkinson’s disease(PD)provides opportunities for early intervention to slow the progression of neurological degeneration in patients,particularly as the aging population increases in our society.Among a series of pathological features of PD,mitochondria abnormalities have been identified as central event that occurs at the early stage of PD.However,the method for detecting mitochondrial abnormalities-associated early PD has not been fully developed.We herein report a specifically mitochondrial targeting probe(named TPA-BT-SCP)that is able to characterize mitochondria abnormalities for early diagnosis of PD and monitor PD neurodegenerative progress.The probe is an aggregation-induced emission(AIE)probe with a strong positive charge,a 3D distorted molecular structure,and a separated HOMO-LUMO distribution,designed with unique molecular design guidelines.Our research demonstrated that TPA-BT-SCP could emit stable and strong fluorescence,and rapidly accumulate in mitochondria due to the negative charge.After intranasal administration of 1-methy-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)-induced PD mice,TPA-BT-SCP successfully bypassed the blood−brain barrier to light up the brain,allowing the grading of PD severity based on its high sensitivity.Taken together,this work develops a novel AIE probe that exhibits dramatically high sensitivity to mitochondrial changes and enables noninvasive diagnosis of early PD in the brain.

Application of Human Adenovirus Genotyping by Phylogenetic Analysis in an Outbreak to Identify Nosocomial Infection

Nosocomial infections are common in pediatric patients and can be fatal in infants and immunocompromised patients. In September 2018, a high positive rate of human adenovirus HAdV was occurred among hospitalized children in the Children's Hospital Affiliated to the Capital Institute of Paediatrics in Beijing. To investigate whether this outbreak of HAdV was related to nosocomial infections or the result of community infections, we collected respiratory specimens from patients with acute respiratory infections in a respiratory ward during June to December 2018, and screened for respiratory viruses. Among 1,840 cases included, 95(5.2%, 95/1840) were positive for HAdV and 81 were genotyped based on phylogenetic analysis, including seven as HAdV-1(8.6%), 30 HAdV-3(37.0%), two HAdV-6(2.5%), and 42 HAdV-7(51.9%). More HAdV-positive samples were collected in August(4.7%, 12/255), September(15.0%, 41/274) and October(6.9%, 17/247), with a peak in September 2018. By combining the results of HAdV phylogenetic analysis with clinical data of patients, there were 77 cases(4.2%, 77/1840;81.1%, 77/95) excluded from nosocomial infections, eight cases representing possible infections transmitted by visitors or attending parents, three cases without sequences that might have been due to infection transmitted by roommates positive for HAdV, one case of a roommate without an HAdV sequence, and six cases that shared highly homologous sequences with those of their roommates, for which nosocomial infections might be considered. In conclusion, genotyping of HAdVs based on phylogenetic analysis combined with clinical information provides a powerful method to distinguish nosocomial infections from community acquired infection, especially when tracing the origins of nosocomial infections.

Taxifolin attenuates inflammation via suppressing MAPK signal pathway in vitro and in silico analysis

Objective:Taxifolin is a natural flavonoid compound that can be isolated from onions,grapes,oranges and grapefruit.It also acts as a medicine food homology with extraordinary antioxidant and antiinflammatory activity.This study aims to explain the protective effects and potential mechanisms of taxifolin against inflammatory reaction.Methods:Levels of interleukin(IL)-6,IL-1βand intracellular reactive oxygen species(ROS)were assessed in different time after the treatment of taxifolin in RAW264.7 cells induced by lipopolysaccharide(LPS).Subsequently,the m RNA and protein levels of inducible nitric oxide synthase(i NOS),vascular endothelial growth factor(VEGF),cyclooxygenase(COX)-2,tumor necrosis factor(TNF)-a and the phosphorylation expression levels of the MAPK signal pathway were also evaluated.A silico analysis was used to explain the binding situation for the investigation of taxifolin and MAPK signal pathway.And then MAPK inhibitors were used to reveal the expression level of i NOS,VEGF,COX-2 and TNF-a in RAW264.7 cells.Results:It was demonstrated that cell inflammatory damage induced by LPS was significantly alleviated after the treatment of taxifolin.Then,the m RNA and protein levels of i NOS,VEGF,COX-2 and TNF-a were reduced and the phosphorylation expression levels of the MAPK signal pathway were down-regulated remarkably as well.In silico analysis,taxifolin could form a relatively stable combination with MAPK signal pathway.MAPK inhibitors showed increasing or decreasing effect in the m RNA levels of i NOS,VEGF,COX-2 and TNF-a,which suggesting that taxifolin down-regulated i NOS,VEGF,COX-2 and TNF-a expressions were not entirely through the MAPK pathway.Conclusion:This finding demonstrated that taxifolin improved the inflammatory responses that partly involved in the phosphorylation expression level of MAPK signal pathway in RAW264.7 cells exposed to acute stress.