多官能度水性光敏聚氨酯丙烯酸酯的合成及性能研究

用异佛尔酮二异氰酸酯(IPDI)、丙三醇、聚四氢呋喃醚二醇(PTMG)、甲基丙烯酸羟乙酯(DMPA)、季戊四醇三丙烯酸酯(PETA)等原料合成了具有高交联度的多官能度紫外光固化聚氨酯丙烯酸酯(PUA)水乳液。采用国标GB12009.4—89,FT-IR,13C NMR,DMA,AFM等方法对PUA预聚体合成过程和聚合物乳液(涂膜)进行了测试和表征,考察了n(IPDI)∶n(HO—OH)∶n(丙三醇)、DMPA质量分数、pH值等对乳液及涂膜性能的影响。结果表明,随着丙三醇质量分数增大,PUA光固化速率、耐溶剂性、膜硬度提高、吸水率降低;随着DMPA质量分数的增加,PUA涂膜硬度、吸水率增强,乳胶粒径越来越小;随着中和度增大,乳液逐渐由云雾状趋向透明,粘度下降。当n(IPDI)∶n(HO—OH)∶n(丙三醇)=9∶6∶1,w(丙三醇)=2%左右,DMPA质量分数为4.6%,中和度为90%时,乳液储存稳定(30 d),涂膜光固化速率达到7 s,附着力为1,硬度为3 H,耐水性、耐化学品性更佳。     

Synthetic lubricants based on sebacic complex esters

This paper presents the results of a study carried out in order to produce synthetic ester oils of a mixed structure based on sebacic acid with beneficial tribological properties. These series of unsymmetrical diesters were synthesized using superior aliphatic alcohols such as 2‐ethyl‐hexanol, isodecanol and isotridecanol, along with special alcohols of a complex alkyl‐aryl structure, namely 2‐phenoxy‐ethanol, 2‐[(o‐sec butyl) phenoxy] ethanol and 2‐[(p‐nonyl) phenoxy] ethanol. Also synthesized were symmetric esters based on the complex aliphatic‐aromatic alcohols with pendant aliphatic chain. The variation in the principal properties as a function of both the length of the aliphatic chain introduced by the aliphatic alcohol, and the length and position of the aliphatic pendant chain on the aromatic nucleus of the complex alkyl‐aryl alcohol was assessed. Based on this, it has been possible to obtain fluid products with variable properties. The introduction of the aromatic function in the structure of these diesters led to interesting features, and the superior values recorded for the main tribological characteristics demonstrated their versatility. Copyright © 2006 John Wiley & Sons, Ltd.     

Patients Recovering from Severe COVID-19 Develop a Polyfunctional Antigen-Specific CD4+ T Cell Response

Specific T cells are crucial to control SARS-CoV-2 infection, avoid reinfection and confer protection after vaccination. We have studied patients with severe or moderate COVID-19 pneumonia, compared to patients who recovered from a severe or moderate infection that had occurred about 4 months before the analyses. In all these subjects, we assessed the polyfunctionality of virus-specific CD4+ and CD8+ T cells by quantifying cytokine production after in vitro stimulation with different SARS-CoV-2 peptide pools covering different proteins (M, N and S). In particular, we quantified the percentage of CD4+ and CD8+ T cells simultaneously producing interferon-γ, tumor necrosis factor, interleukin (IL)-2, IL-17, granzyme B, and expressing CD107a. Recovered patients who experienced a severe disease display high proportions of antigen-specific CD4+ T cells producing Th1 and Th17 cytokines and are characterized by polyfunctional SARS-CoV-2-specific CD4+ T cells. A similar profile was found in patients experiencing a moderate form of COVID-19 pneumonia. No main differences in polyfunctionality were observed among the CD8+ T cell compartments, even if the proportion of responding cells was higher during the infection. The identification of those functional cell subsets that might influence protection can thus help in better understanding the complexity of immune response to SARS-CoV-2.