Glycopeptides by Linch-Pin C−H Activations for Peptide-Carbohydrate Conjugation by Manganese(I)-Catalysis

Late-stage C−H glycosylations of structurally complex amino acids and peptides were accomplished by means of racemization-free manganese(I)-catalyzed C−H activation. Thus, glycosylative modifications proved to be viable by a linch-pin approach, featuring chemo- and site-selective C−H transformations. The peptide–saccharide conjugation provided modular access to structurally complex glycopeptides, likewise enabling the assembly of fluorescent-labelled glycopeptides.     

Unravelling the Time Scale of Conformational Plasticity and Allostery in Glycan Recognition by Human Galectin-1

The interaction of human galectin-1 with a variety of oligosaccharides, from di-(N-acetyllactosamine) to tetra-saccharides (blood B type-II antigen) has been scrutinized by using a combined approach of different NMR experiments, molecular dynamics (MD) simulations, and isothermal titration calorimetry. Ligand- and receptor-based NMR experiments assisted by computational methods allowed proposing three-dimensional structures for the different complexes, which explained the lack of enthalpy gain when increasing the chemical complexity of the glycan. Interestingly, and independently of the glycan ligand, the entropy term does not oppose the binding event, a rather unusual feature for protein-sugar interactions. CLEANEX-PM and relaxation dispersion experiments revealed that sugar binding affected residues far from the binding site and described significant changes in the dynamics of the protein. In particular, motions in the microsecond-millisecond timescale in residues at the protein dimer interface were identified in the presence of high affinity ligands. The dynamic process was further explored by extensive MD simulations, which provided additional support for the existence of allostery in glycan recognition by human galectin-1.     

A simple and high‐resolution HPLC‐PDA method for simultaneous quantification of local anesthetics in in vitro buccal permeation enhancement studies

A simple, isocratic, high‐resolution and prompt HPLC‐PDA method was developed and validated for the simultaneous quantification of prilocaine (PCL) and lidocaine (LCL) hydrochlorides in in vitro buccal iontophoresis‐driven permeation studies. A reversed‐phase C₁₈ column (250 mm x 4.6 mm, 3μm, 110Å) was used for the chromatographic separation. The mobile phase contained acetonitrile: 0.1M sodium phosphate buffer, pH 7.0 (1:1, v/v), plus 0.05% (v/v) diethylamine. The isocratic flow rate was set at 1 mL/min and the detection wavelength was 203 nm. PCL and LCL eluted in 8.9 min and 13 min, respectively, and the system suitability parameters varied within an acceptable range. The method was selective, sensitive, precise, accurate and robust, producing a linear plot at the concentration range of 0.25 to 10 µg/mL. The application of this method was demonstrated by a significant enhancement of the permeation of PCL and LCL with the application of iontophoresis (1 mA/cm² per 1 h) through isolated porcine esophageal epithelium. The amount of the drug retained in the epithelium also increased with the application of an electrical current. Copyright © 2015 John Wiley & Sons, Ltd.     

Electrodeposition of nanostructured catalysts for electrochemical energy conversion: Current trends and innovative strategies

This review discusses the latest advances in electrodeposition of nanostructured catalysts for electrochemical energy conversion: fuel cells, water splitting, and carbon dioxide electroreduction. The method excels at preparing efficient and durable nanostructured materials, such as nanoparticles, single atom clusters, hierarchical bifunctional combinations of hydroxides, selenides, phosphides, and so on. Yet, in most cases, chemical composition cannot be decoupled from catalyst morphology. This compromises the rational design of electrodeposition procedures because performance indicators depend on both morphology and surface chemistry. We expect electrodeposition will keep unraveling its potential as the preferred method for electrocatalyst synthesis once a deeper understanding of the electrochemical growth process is combined with complex chemistries to have control of the morphology and the surface composition of complex (bifunctional) electrocatalysts.     

On a nonlinear boundary value problem modeling corneal shape

In this paper we present some results concerning a boundary value problem for a nonlinear ordinary differential equation that was used before in modeling the topography of human cornea. These results generalize previously obtained theorems on existence and uniqueness. We show that our equation has a unique solution for all parameters and conditions that can arise in physical situation. In the second part of the article we derive some new estimates and approximate solutions. Numerical calculations verify that these approximations are very accurate.