Amphiphilic block glycopolymers via atom transfer radical polymerization: Synthesis,self‐assembly and biomolecular recognition

In this work the synthesis of poly(butyl acrylate)‐b‐poly(2‐{[(D ‐glucosamin‐2‐N‐yl)carbonyl]oxy}ethyl methacrylate) (PBA‐b‐PHEMAGl) diblock glycopolymer and poly(2‐{[(D ‐glucosamin‐2‐N‐yl)carbonyl]oxy}ethyl methacrylate)‐b‐poly(butyl acrylate)‐b‐poly(2‐{[(D ‐glucosamin‐2‐N‐yl)carbonyl]oxy}ethyl methacrylate) (PHEMAGl‐b‐PBA‐b‐PHEMAGl) was performed via atom transfer radical polymerization. Monofunctional and difunctional poly(butyl acrylate) macroinitiators were used to synthesize the well‐defined diblock and triblock glycopolymers by chain extension reaction with the glycomonomer HEMAGl. The self‐assembly of these glycopolymers in aqueous solution was studied by dynamic light scattering and transmission electron microcopy, showing the coexistence of spherical micelles and polymeric vesicles. In addition, the biomolecular recognition capacity of these micelles and vesicles, containing glucose moieties in their coronas, was investigated using the lectin Concanavalin A, Canavalia Ensiformis, which specifically interacts with glucose groups. The binding capacity of Concanavalin A with glycopolymer is influenced by the copolymer composition, increasing with the length of HEMAGl glycopolymer segment in the block copolymer. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Embedding of Biological Regulatory Networks and Property Preservation

In the course of understanding biological regulatory networks (BRN), scientists usually start by studying small BRNs that they believe to be of particular importance to represent a biological function, and then, embed them in a larger network. Such a reduction can lead to neglect relevant regulations and to study a network whose properties can be very different from the properties of this network viewed as a part of the whole. In this paper we study, from a logical point of view, on which conditions concerning both networks, properties can be inherited by BRNs from sub-BRNs. We give some conditions on the nature of the network embeddings ensuring that dynamic properties on the embedded sub-BRNs are preserved at the level of the whole BRN.     

Associative and segregative phase separations of poly(N-tert-butylacrylamide)/poly(acrylic acid) mixtures. Effect of solvent

Poly(N-tert-butylacrylamide) (PNtBAm) and poly(acrylic acid) (PAA) form interpolymer complexes in 1- and 2-propanol, blend in ethanol, whereas a segregative phase separation is observed when using methanol as solvent as shown by Fourier transform infrared (FTIR) spectrometry and elemental analysis studies. The composition of PNtBAm/PAA complexes has been determined. Thermal studies demonstrated that all complexes show unique glass transition temperatures, higher than those of the polymer components. Complexation of PAA with PNtBAm results in an improvement of its thermal stability. Solvent effects and specific interactions in the system PNtBAm/PAA have been studied by FTIR, revealing that differences in the polymer–solvent interactions are a decisive factor governing complex formation in solution.     

Counterexamples on L_p-maximal regularity

We establish a transference result for -maximal regularity for the abstract Cauchy problem on Banach space. From this result we deduce counterexamples to -maximal regularity In particular we obtain an operator B without any -maximal regularity although it admits bounded imaginary powers with for all . We also derive an operator which satisfies -maximal regularity on bounded intervals [0, T[ but not on the half line Received March 5, 1997; in final form October 10, 1997     

南昌市前湖区春季鸟类群落结构

2007年3～5月我们通过调查南昌市前湖区春季鸟类群落结构,结果表明共记录了959只鸟类个体,隶属于11目、26科、54种,其中雀形目和鹳形目鸟类属于绝对的优势目.鸟类居留型组成不管是个体数量还是种数的分布,留鸟占有的比例都最高,分别为45%和41%.前湖地区鸟类群落多样性指数为2.86,均匀度指数为0.72.在划分的7个生境中,洼地群落具有最高的多样性和均匀度,分别为2.93和0.92.总之,前湖地区生境受到人类活动影响深刻,该区分布的优势种主要为一些与人类关系比较密切的伴生种.     

Synthetic studies towards diazepanone scaffolds

The synthesis of new enantiopure polyfunctionalised diazepanone scaffolds is described. The key steps involve the opening of an azido-epoxide C4 building block derived from l-ascorbic or d-isoascorbic acid by a l-serine derivative followed by a lactonisation–lactamisation two-step sequence.     

Site-specifically Hydrolytic Cleavage of Oxidized Insulin B Chain With Cu(II) Ion

Selectively chemical cleavage of peptides and proteins is one of the most important reactions in both chemical and biochemical processes. Over the past decade, the interaction of palladium(II) complexes with methionine, cysteine and histidine-containing peptides and proteins and the hydrolytic cleavage of the corresponding amide bond by Pd(II) complexes have been extensively studied1-13. However, reports concerning the directly selective hydrolysis of peptides and proteins with other simple …