Interaction of pyrene-end-capped poly(ethylene oxide) with bovine serum albumin and human serum albumin in aqueous buffer medium: a fluorometric study

The photophysical behavior of a hydrophobically tailored water-soluble polymer, pyrene-end-capped poly(ethylene oxide) (PYPY), has been studied in aqueous buffered bovine serum albumin (BSA) and human serum albumin (HSA) media. In buffered aqueous solution the polymer shows dual emission corresponding to the monomer and the excimer of pyrene moiety. The relative intensity of the monomer to the excimer emission shows interesting variation with the addition of BSA and HSA and is indicative of significant interaction of these albumin proteins with the polymer. The binding interaction has been shown to have a prominent role on the steady state fluorescence anisotropy of the two emission bands. Attempt has been made to determine the micropolarities of the protein microenvironments from a comparison of the variation of the monomer to excimer relative fluorescence intensities of the probe in water–dioxane mixtures with varying composition.     

Stereoselective synthesis of 2-epi-jaspine B via base-catalyzed intramolecular oxy-Michael conjugate addition approach

2-epi-Jaspine B has been synthesized starting from (−)-diethyl tartrate in 12 simple steps and 26.6% overall yield. The key intermediate was obtained via stereoselective base-catalyzed intramolecular oxy-Michael conjugate addition followed by tandem hydrogenation/hydrogenolysis.     

Photophysical studies on multichromophoric cyclotriphosphazenes. Trinuclear excimer formation in hexakis(2-naphthyloxy)cyclotriphosphazene

Hexakis(2-naphthyloxy)cyclotriphosphazene showed an interesting emission behavior between its monomer and excimer forms, the latter nearly completely dominating in water. Encapsulation studies with β-cyclodextrin in water partially revived the monomer emission.     

Robustness Screen in Enantioselective Catalysis Enabled Generation of Enantioenriched Heterocyclic Scaffolds in One Pot

Enantioselective catalysis has emerged as a powerful synthetic paradigm and has accelerated the development of new methods to make diverse chiral molecules. Generally, these reactions are very sensitive to the steric and electronic environment present in the catalyst as well as the substrates. With this scenario, the presence of an additional component in the reaction mixture is expected to add complexity in achieving the enantioselective variants. Herein, we report that various enantioenriched molecules could be obtained from multiple starting materials in one pot. The reaction of aminoaromatics A with alkynols B₁, B₂, B₃…?B_n with a Au^I/chiral Brønsted acid catalyst afforded AB₁*, AB₂*, AB₃*…AB_n*; while, the reaction of alkynols B with aminoaromatics A₁, A₂, A₃…A_n under the same reaction conditions gave A₁B*, A₂B*, A₃B*…A_nB * .     

Numerical Solution of Large Scale Sparse Matrix Equations in Python

The M.E.S.S. software suite for solving large scale matrix equations and related problems is the successor of the obsolete LyaPack MATLAB® toolbox. The software suite consists of a new MATLAB toolbox and a separate C library C-M.E.S.S. which works independent from MATLAB. Due to the fact that many scientists use Python with NumPy and SciPy for their computations, we want to provide the key algorithms of M.E.S.S. there as well. In this paper, we describe and compare two possible approaches for the implementation, with special focus on their multicore performance. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

International Guidelines for Bioanalytical Method Validation: A Comparison and Discussion on Current Scenario

US FDA released guidelines for bioanalytical method validation in 2001 and it became the basis for guidelines such as ANVISA and EMA. Even though there is a general agreement between these guidelines in terms of evaluation of validation parameters, significant diversity exists with respect to methodology employed. Present review compares and summarizes the regulatory guidelines issued by US FDA, ANVISA and EMA for bioanalytical method validation. This review also discusses evaluation of certain validation parameters such as matrix effect, incurred sample reanalysis, various stability aspects, effect of anticoagulant counter ions, specificity in the presence of concomitant medications, and identification of pharmacokinetic repeats wherein specific guidance and general consensus amongst scientific community does not exist.