γ-聚谷氨酸水凝胶的性质、制备及其应用

系统介绍了γ-聚谷氨酸水凝胶的制备方法及其生物可降解性、高吸水性及保湿性、pH敏感性、生物相容性和可修饰性等性能,同时综合介绍了其在组织工程、药物控释和创面修复等方面的应用,结合本研究组工作对其未来的发展进行了展望。     

嵌段共聚物和星型均聚物共混体系相行为的自洽场理论研究

用自洽场理论方法(Self-consistent field theory, SCFT)计算了嵌段共聚物AB和三等臂星型均聚物A共混体系的微相形态. 为了简化计算, 着重讨论了固定嵌段共聚物本体的相形态(如层状相)时, 所加入的均聚物的体积分数及均聚物与嵌段共聚物链长之比对体系相形态的影响; 并结合体系的熵和相互作用能的变化, 讨论了星型均聚物在体系微相结构中的分布.     

Synthesis of a pH-independent bifurcated amphiphile

An efficient synthetic method for preparing bifurcated amphiphiles has been developed such that the functionality for attachment is located at the interface between the lipophilic and hydrophilic side chains. Attachment of the amphiphile to the repeat units of polymeric substrates enables the rapid preparation of amphiphilic homopolymers.     

Dynamical relaxations in mixtures of different polymers and nonsymmetrical copolymers in solution

Dynamical relaxation properties of nonsymmetrical mixtures of homopolymers and of copolymers in solution are examined. In particular, examples of bimodal mixtures in solution, ternary mixtures of two different homopolymers and a solvent, and nonsymmetrical diblock copolymers in solution are examined. The frequencies of the eigenmodes Γ and Γ′, those of the cooperative mode Γ_T and the interdiffuse mode Γ_I are calculated for these systems. It is found that the variations of T_T and T_I, with the scattering wave number q are practically identical to those of Γ_T and Γ_I, respectively. This identity is rigorous only for mixtures or copolymers where the two polymer components are identical except for their contrast factors (i.e., indices of refraction or scattering lengths). Here, it is argued that the identification of the eigenmodes with the cooperative and interdiffuse modes can be extended qualitatively to mixtures of different polymers and to nonsymmetrical copolymers in solution.     

TheMichaelis-Menten equation in the case of enzyme-catalyzed hydrolysis of linear homopolymer substrates with different degrees of polymerization

A novel theory has been proposed allowing the derivation of the equation ofMichaelis-Menten valid in the case of enzyme-catalyzed hydrolysis of linear homopolymer substrates with varying degrees of polymerization. This equation permits the definition of the maximal rate (V) of the enzyme reaction increasing with the molecular mass of the substrate and theMichaelis-Menten constant (Km) decreasing with the increase of the number of bonds in the substrate molecule. Two new methods have been developed permitting: 1. Determination of theMichaelis-Menten constant (Km') for a single substrate bond; and 2. Calculation of the free energy ( G) required for the formation and degradation of a single enzyme-substrate complex. The theory explains a number of experimental results published by other authors.

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Über die Gültigkeit derMichaelis-Menten-Gleichung bei der enzymkatalysierten Hydrolyse von linearen homopolymeren Verbindungen unterschiedlichen Polymerisationsgrades

Zusammenfassung Aufgrund neuer Überlegungen ist es möglich, die Gleichung nachMichaelis-Menten auf die enzymkatalysierte Hydrolyse von homopolymeren Körpern linearer Struktur mit verschiedenem Polymerisationgrad anzuwenden. Die Gleichung erlaubt die Erfassung der maximalen Enzym-Reaktionsgeschwindigkeit (V), die sich mit dem Molekulargewicht des Substrates erhöht, sowie derMichaelis-Menten-Konstante (Km), die sich mit zunehmender Anzahl von Verknüpfungen vermindert. Es wurden zwei neue Verfahren entwickelt: Erstens die Bestimmung derMichaelis-Menten-Konstante (Km') für eine Substratbindung, zweitens die Berechnung der freien Energie ( G) für die Bildung bzw. für die Zerlegung eines Enzym-Substrat-Komplexes. Die Theorie erklärt eine Reihe von Versuchsergebnissen, die von anderer Seite bereits veröffentlicht worden sind.