Binding of caffeic acid to human serum albumin by the retention data and frontal analysis

A new mathematical model and frontal analysis were used to characterize the binding behavior of caffeic acid to human serum albumin (HSA) based on high‐performance affinity chromatography. The experiments were carried out by injecting various mole amounts of the drug onto an immobilized HSA column. They indicated that caffeic acid has only one type of binding site to HSA on which the association constant was 2.75 × 10⁴/m . The number of the binding site involving the interaction between caffeic acid and HSA was 69 nm . The data obtained by the frontal analysis appeared to present the same results for both the association constant and the number of binding sites. This new model based on the relationship between the mole amounts of injection and capacity factors assists understanding of drug–protein interaction. The proposed model also has the advantages of ligand saving and rapid operation. Copyright © 2014 John Wiley & Sons, Ltd.     

Glutaraldehyde crosslinking of arabinoxylan produced from corn ethanol residuals

This study investigated the possibility of substituting petroleum-based polymers with biopolymers for films and paper coatings. Arabinoxylan (AX) was extracted from distillers’ grains, a low-value corn ethanol byproduct, and modified through crosslinking with glutaraldehyde (GA) which was made into films and paper coatings. The effects of degree of substitution (DS) on film and coating properties of GA cross-linked AX, referred to as GAX, were investigated. The GAX films had markedly higher tensile strength, approximately 3 times higher than the unmodified AX films at low DS, with higher DS causing a negative effect on the film tensile strength. Compared to unmodified AX coating, paper coated with GAX also had significantly higher tensile index, presumably due to high adhesion between the coating and paper interface. When used as a coating binder with calcium carbonate pigments, GAX showed comparable performance to polyvinyl alcohol, a common industrial binder, demonstrating the potential to be substituted for the petroleum-based paper coating binder.     

Global Pathway Analysis: a hierarchical framework to understand complex chemical kinetics

An automated hierarchical framework, Global Pathway Analysis (GPA), is presented to understand complex chemical kinetics. The behaviour of the reacting system at macro level is bridged to the elementary reaction level by Global Pathways, which are the chemical pathways from an initial reactant species to a final product species. For each Global Pathway, its dominancy and effect on the system, such as those on the production or consumption of radicals, are quantified to understand its contribution to the system. Four examples are presented as demonstration: First, the classical second explosion limit of hydrogen is found to be resulted from the change of dominancy of a pressure-dependent Global Pathway, which consumes radical via H?+?O₂?+?M?=?HO₂?+?M reaction. Next, it is found that the negative temperature coefficient (NTC) regime of n-heptane is resulted from the competition between a low-temperature Global Pathway and a high-temperature Global Pathway. Third, a non-monotonic relation between autoignition delays and toluene ratio in toluene/n-decane mixture is analysed. This automated framework has been placed in public domain. Reduced kinetic models can be generated based on Global Pathways too. Finally, this methodology is demonstrated using DNS simulation results of the extinction and re-ignition of a turbulent non-premixed flame. The differences between simulation results are investigated using two different kinetics models via the analysis of global pathways.