Surface modifications of molecularly imprinted polymers for improved template recognition in water media

New Restricted Access Materials—Molecularly Imprinted Polymers (RAM-MIP) were synthesized by using caffeine (CAFF), methacrylic acid (MAA), divinyl benzene (DVB) and glycidil methacrylate (GMA) as model template, functional monomer, crosslinking agent and pro-hydrophilic co-monomer, respectively. Furthermore, a screening of the ratio of functional monomer to template was performed. After the preliminary characterizations of conventional MIP prepared in absence of GMA, different GMA amounts were inserted in the pre-polymerization feeds and different reactions conditions were tested for GMA epoxide ring opening. In particular, perchloric acid, ammonia, lactic acid, glycine and triethylene glycol were chosen for this purpose. In perchloric acid and ammonia cases, a further modification was performed by phosphorylation and methylation procedures, respectively. Imprinting efficiency of all the obtained materials was evaluated by binding experiments using caffeine and its analogue theophylline both in organic and in water media. The increased hydrophilic characteristics of RAM polymers by water absorption measurement and protein binding experiments were performed.     

Local Bond-Slip Relationship for FRP Reinforcement in Concrete

The objective of this paper is to define a rigorous numerical method to calibrate parameters of a given local bond-slip relationship using experimental results of pullout tests, taking into account the distribution of the slip and bond shear stress throughout the bar. The proposed method involves finding parameters of a given bond-slip relationship, such that results of pullout tests can be predicted in terms of applied pullout force and consequent slip at the loaded end and slip at the free end. The method is applied to some experimental data, and the results are discussed. For the application of the proposed method, two analytical expressions of the bond-slip relationship are selected, even though it could be applied to any analytical expression. An example of determination of anchorage length starting from the knowledge of the local bond-slip relationship is given.     

A method for acceptability region representation in analogue linear networks

A new simple approach to acceptability region representation in analogue linear circuit design is presented. The proposed method is also able to characterize non‐convex and disjoint acceptability regions with low computational effort. In fact, the developed procedure is based on the use of symbolic analysis techniques, which permit one to perform only one simulation of the circuit under consideration, thus reducing the computational efforts. The theoretical basis and the algorithm implementing the technique are presented. A circuital example is also included. Copyright © 2008 John Wiley & Sons, Ltd.     

Polypyrrole grafting onto the surface of pyrrole-modified silica nanoparticles prepared by one-step synthesis

The grafting of polypyrrole onto the surface of modified silica nanoparticles has been investigated. These silica nanoparticles were modified with pyrrole moieties prepared by the well-known Stober method in one-step starting from TEOS and a pyrrole-bearing trialkoxysilane compound. The effects of various reaction conditions, including reaction time, solvent, and molar ratio of water to alkoxy groups, have been investigated in order to obtain pyrrole-modified silica nanoparticles with the optimal core–shell structure and the smallest possible particle size. The grafting was carried out in aqueous FeCl₃ solution containing the modified silica nanoparticles, with pyrrole monomers already adsorbed on the surface of the particles by soaking. Several analytical tools have been employed to characterize the particles and to assess the degree of grafting, namely TEM, SEM, TGA, FTIR, and XPS. The final polypyrrole-grafted silica nanoparticles obtained had a mean diameter of about 220 nm and 50 wt.% of grafted polypyrrole with respect to the total weight of polypyrrole formed around the surface of the cores.     

The effect of phosphatidylserine on golf performance

Background  

A randomized, double-blind, placebo-controlled study was performed to evaluate the effect of oral phosphatidylserine (PS) supplementation on golf performance in healthy young golfers with handicaps of 15–40.