基于透明质酸生物活性自组装胶体粒子制备及乳化性能

用透明质酸(HA)和溶菌酶(Lys)静电自组装制备胶体粒子.研究了溶菌酶和透明质酸的质量比(WR)对胶体粒子性质的影响,得到最佳质量比下的胶体粒子.用纳米粒度仪和透射电镜对胶体粒子的尺寸和形貌进行表征.结果显示,形成的胶体粒子为球形结构,粒径约250 nm.此胶体粒子可二次组装在油水界面稳定水包油型类凝胶Pickeri...     

光敏共聚物P(St/VM-co-MA)自组装胶体粒子及其性能

以苯乙烯类光敏单体7-(4-乙烯基苄氧基)-4-甲基香豆素(VM)、苯乙烯(St)、马来酸酐(MA)为共聚单体,采用自由基聚合法制备了光敏性双亲共聚物P(St/VM-co-MA).在选择性溶剂(N,N-二甲基甲酰胺(DMF)/H2O)中对P(St/VM-co-MA)进行自组装,用透射电镜(TEM)和动态激光光散射(DLS)表征了自组装胶体粒子的形态、粒径大小及其分布.利用紫外光照使胶体粒子中香豆素基元发生光二聚反应,形成交联胶体粒子,并用紫外-可见光分光光度计(UV-Vis)跟踪其交联过程.用DLS研究了交联和未经交联胶体粒子的粒径和结构稳定性,用激光扫描共聚焦显微镜(LSCM)和光学显微镜考察了胶体粒子的乳化、包覆性能.结果表明:交联和未经交联胶体粒子均具有乳化性,且在乳化过程中可实现对油溶性染料的包覆.胶体粒子交联后,粒径有所减小,结构稳定性、乳化性能、包覆性能均有所提高.     

胶体粒子的机械性能调控及其在药物递送中的应用

胶体粒子是肿瘤治疗中最常用的载体, 尽管在过去的研究中不同的胶体粒子已经被广泛报道, 但如何进一步提高胶体粒子的药物递送效率仍然存在着一些挑战. 大量的研究表明胶体粒子的尺寸、形状、结构和表面化学等物理化学性质在药物递送过程中具有重要的作用, 但胶体粒子的机械性能对药物递送过程的影响研究和综述相对较少. 本综述从不同机械性能胶体粒子的制备与表征出发, 概述了胶体粒子的机械性能对血液循环、肿瘤富集、渗透以及细胞内化过程的影响, 并对该领域存在的问题以及发展的趋势进行了展望. 该综述有助于帮助科学工作者更好地理解胶体粒子的机械性能对药物递送的影响规律, 从而优化胶体粒子的设计并提高纳米药物的递送效率和生物利用率.     

Lennard-Jones流体中胶体粒子间耗尽势的密度泛函理论研究

基于Roth, Evans和Dietrich有关耗尽势的密度泛函理论研究了Lennard-Jones (L-J)流体中胶体粒子间的耗尽势. 通过计算胶体稀溶液中两个胶体粒子在不同条件下的耗尽势, 进一步分析了L-J流体的相关因素对耗尽势的影响. 结果表明, L-J流体分子的体积分数、胶体粒子与溶剂分子的尺寸比率、L-J流体分子间的相互作用以及胶体粒子与流体分子之间的弱相互作用等因素均可对胶体粒子间耗尽势产生显著影响. 研究结果可为实验上调控胶体粒子间的相互作用提供可能的线索.     

胶体晶体剪切模量的影响因素

利用自行搭建的扭转共振谱仪,研究了不同粒子体系胶体晶体在不同体积分数下的剪切模量,利用反射光谱测量了相应的晶体结构及内部孔洞等参数.结果表明,同一粒子体系的剪切模量均随体积分数的增加而增大;而对于同样的粒子数密度,不同粒子体系的剪切模量随体系内部孔洞所占比例增加呈增大趋势.对实验结果的分析及与理论分析的对比表明,决定胶体晶体剪切模量大小的主要因素是胶体晶体中粒子的最近邻间距,从而统一解释了体积分数和内部孔洞对胶体晶体剪切模量的影响.     

AaDd型氢键流体的统计理论（Ⅳ）：胶体粒子间的耗尽势

基于耗尽势的密度泛函理论研究了AaDd型氢键流体中胶体粒子间的耗尽势.针对胶体稀溶液,通过计算在不同条件下两个胶体粒子间的耗尽势和耗尽力,进一步分析了氢键流体中相关因素对二者的影响.结果表明,胶体粒子与流体分子的尺寸比率、氢键流体的体相密度、氢键键能、质子给体和受体数目以及胶体粒子与流体之间的弱相互作用等因素均可对胶体粒子间耗尽势产生显著影响.     

硬核Yukawa流体中胶体粒子间的耗尽势

基于Roth、Evans和Dietrich有关耗尽势的密度泛函理论研究了硬核Yukawa(HCY)流体中胶体粒子间的耗尽势.在极稀溶液条件下,通过计算两个胶体粒子在不同条件下的耗尽势,分析了HCY流体的相关因素对耗尽势的影响.结果表明,胶体粒子与溶剂分子的尺寸比率、HCY流体分子间的相互作用、HCY流体分子的体相密度以及胶体粒子与流体分子之间的相互作用等因素均可对胶体粒子间耗尽势产生显著影响.研究结果可为实验上调控胶体粒子间的相互作用提供可能的线索.     

微凝胶胶体晶体研究进展

Poly(N-isopropylacrylamide)(PNIPAM)微凝胶粒子是一种软的胶体粒子.和单分散的SiO_2、PS、PMMA等硬的胶体粒子一样,单分散的PNIPAM微凝胶粒子也可以自组装成为高度有序的胶体晶体.微凝胶粒子软物质的特性及其对外部刺激的响应性赋予其不同于硬球的组装行为.微凝胶胶体晶体的高度有序结构及其刺激响应性使其在诸多领域有重要用途.本文分别介绍了三维及二维微凝胶胶体晶体组装的研究进展,并对已开发的基于微凝胶胶体晶体的应用进行了总结.     

缔合流体中胶体粒子间耗尽势的密度泛函理论研究

本文基于Roth、Evans和Dietrich有关耗尽势的密度泛函理论研究了缔合流体中胶体粒子间的耗尽势. 通过计算在不同条件下两个胶体粒子间的耗尽势, 进一步分析了缔合流体中相关因素对耗尽势的影响. 结果表明, 溶剂分子的体相密度、胶体粒子与溶剂分子的尺寸比率、溶剂分子的官能度和缔合强度以及胶体粒子与溶剂分子之间的弱相互作用等因素均可对胶体粒子间耗尽势产生显著影响.     

多核核壳结构银胶粒的制备及其抑菌特性

银纳米粒子具有广谱抗菌性,但自身由于具有较高的表面能容易发生团聚.本文以聚醚胺为还原剂和稳定剂,利用光化学还原法,合成了聚乙二醇包覆的银纳米粒子.通过透射电子显微镜分析表明该胶体粒子具有多核核壳结构,聚乙二醇包裹的银纳米颗粒粒径在14 nm左右,整个胶体粒子粒径在45 nm左右.抑菌实验结果表明这种银纳米胶体对大肠杆菌和金黄色葡萄球菌有明显的抑菌效果.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.