群体感应系统及其在乳酸菌生物膜形成中的作用

以黑果枸杞花青素微胶囊在水相体系中花青素的保留率为指标,采用控制变量法研究了环境因素温度、循环冻融、自然光照、紫外光照对花青素稳定性的影响,进一步研究了花青素的氧化降解规律;采用体外模拟胃肠液的方法对花青素微胶囊的稳定性和靶向释放特性进行了研究。结果表明:花青素微胶囊的热降解符合一级降解动力学模型;微胶囊化花青素在低温和低 pH条件下较稳定,光照能够降低花青素的稳定性。在体外模拟胃肠液稳定性实验中,花青素微胶囊在胃液中比肠液中稳定,与未包埋花青素溶液相比,花青素微胶囊溶液在模拟胃液中其花青素的保留率提高了14.8%,在模拟肠液中提高了17.3%;在体外模拟胃肠液靶向释放实验中,在胃液中,90 min 后,花青素微胶囊溶液和花青素未包埋溶液中花青素的释放率分别为7.5%、20.7%;在肠液中花青素缓慢释放,240 min 后,二者花青素的释放率分别为21.9%、27.2%;并且花青素微胶囊后能够显著提高其在水相体系中的稳定性,起到在胃肠液中缓释的效果。     

Theoretical model of a drying system including turbulence aspects

Biological products contain high moisture content in the harvest period. Such moisture could cause their deterioration in storage. Drying is an interesting solution to keep the quality of these products. Generally, drying process is based on contact of a dry air phase with a wet solid. A theoretical model was developed to describe the dynamic behavior of a forced convection drying process. This model takes into account the entire dynamic phenomenon including turbulence, diffusivity and tortuosity effects. Only the mass transfer of water molecules during vaporization was referred to as an empirical expression. The model thus strongly build, was compared to Thompson’s empirical model. Corn grain was used in the validating process. Transient temperature and water content results are presented.     

两亲性梳型丙烯酸接枝苯乙烯共聚物的制备与溶胀性质初探

以丙烯酸（AA）和对氯甲基苯乙烯（P—CMS）为原料,制备了带有功能性基团苄基氯的大分子引发剂P（AA-co—CMS）,当投料量为AA：p—CMS为95：5时,P—CMS主要以单个单元均匀的分布在AA主链中。再以苄基氯为引发点,在FeCl2／PPh,催化体系下,引发了苯乙烯（st）的ATRP聚合,制得了结构明确的主链亲水、支链疏水的两亲性梳型共聚物P（AA—co—CMS）-g—PS。采用IR和^1H—NMR表征了共聚物的结构,表明使用此法具有接枝引发效率非常高的特点。初步研究了不同接枝率下P（AA-co—CMS）-g—PS的溶胀性质。     

纳米载体两亲性接枝共聚物及其在农药中的应用

两亲性接枝共聚物是纳米胶囊的主要组成部分, 在药物领域得到了广泛的关注。本文综述了两亲性接枝共聚物的研究现状, 重点阐述了两亲性接枝共聚物的制备、性质及其应用, 展望了两亲性接枝共聚物在农药领域中的应用前景。     

重组人促红素等电点异构体分子体内活性强度分析

目的分析重组人促红素(recombinant human erythropoietin,rhEPO)各等电点异构体分子体内活性强度(单位时间单位摩尔量下产生体内活性量),找出最适作用分子。方法根据rhEPO等电点异构体体内比活性数据变化,构建等电点异构体分子与其体内活性之间关系的数学模型,并进行解析。结果得到rhEPO等电点异构体分子体内活性与唾液酸数量关系:S_i=0. 628·e⁽(i-10))·(|i-10|+1)^-2+0. 492,R²> 0. 988 0(i为正整数且16> i> 8,表示rhEPO分子上唾液酸数量;Si表示某等电点异构体体内比活性,体内比活性单位10⁵ IU/mg),在此基础上,进而提出rhEPO与其受体相互作用模型假说(电荷识别-分子内氢键重排-构象变化-排斥解离假说)。结论通过对rhEPO等电点异质性与体内比活性关系的进一步分析,阐述了rhEPO与其受体相互作用存在最适作用分子,并依据上述实验和数据分析提出了rhEPO与其受体相互...     

Blends Containing Amphiphilic Polymers VI. Compatibilization of N-alkylitaconamic acid-co-Styrene Copolymers with Poly(hydroxypropyl methacrylate) and Poly(4-vinylphenol)

Blends containing copolymers of N-alkylitaconamic acid (NAIA) with styrene (NAIA-co-S) of two copolymer compositions, that is, 80% and 50% styrene, with poly(hydoxypropyl methacrylate (PHPM) and poly(vinyl phenol) (PVPh) were studied by differential scanning calorimetry (DSC) and Fourier Transform Infrared spectroscopy (FT-IR). The phase diagrams of Tg against blend composition show one single Tg value, which are intermediate to those of the pure components. This is interpreted as miscibility over the whole range of compositions in both systems. The Calorimetric Analysis using Gordon Taylor, Couchman, and Kwei treatments allows one to conclude that interactions between the components is favorable to the miscibility. FT-IR spectra show important displacements in the wavenumber corresponding to the carbonyl groups of the itaconamic acid moiety. This behavior is atributed to strong interaction by hydrogen bonds formation, taking into account that PHPM and PVPh are interacting polymers. FTIR analysis of the blends suggests that the driving force for miscibility is hydrogen bonds formation. The variation of the absorptions of the carbonyl groups of PNAIA and the hydroxyl groups of P4VPh allows to attribute the miscibility to weak acid-base like interactions.     

Enantioselective Organocatalytic Michael Addition of Cyclobutanones to Nitroalkenes

Synthetic applications of cyclobutanones other than ring expansion and fragmentation reactions are rare. Herein, highly efficient diastereo‐ and enantioselective organocatalytic Michael additions of 2‐substituted cyclobutanone derivatives to nitroalkenes are reported allowing the stereocontrolled creation of ‘all‐carbon’ quaternary centers. The approach relies on both the use of Brønsted base/hydrogen‐bond donor bifunctional organocatalysts, and importantly, the specific stabilization and activation of cyclobutanone with a secondary amide moiety. The reaction was found to nicely accommodate a broad scope of substrates, allowing the control of up to three contiguous stereogenic centers. This work has opened new synthetic opportunities.