Voltammetry of the phase transfer of polypeptide protamines across polarized liquid/liquid interfaces

Using natural polypeptide protamines as the illustrating example, we observed the phase transfer of biological polyions at polarized interfaces between two immiscible electrolyte solutions (ITIES) for the first time by micropipet voltammetry. Analysis of the limiting currents indicates that each protamine carries 20 positive charges as expected from the number of arginine residues in the molecule. Also, it was shown that the shape of the voltammograms is limited by the interfacial transfer of protamines. Coupling of the transfer reactions with interfacial adsorption/desorption of protamines was also observed. ITIES will serve as a basis of amperometric sensors for biological macromolecules and also as a model for understanding potential-driven membrane transport of these molecules.     

A Global Review on Short Peptides: Frontiers and Perspectives

Peptides are fragments of proteins that carry out biological functions. They act as signaling entities via all domains of life and interfere with protein-protein interactions, which are indispensable in bio-processes. Short peptides include fundamental molecular information for a prelude to the symphony of life. They have aroused considerable interest due to their unique features and great promise in innovative bio-therapies. This work focusing on the current state-of-the-art short peptide-based therapeutical developments is the first global review written by researchers from all continents, as a celebration of 100 years of peptide therapeutics since the commencement of insulin therapy in the 1920s. Peptide “drugs” initially played only the role of hormone analogs to balance disorders. Nowadays, they achieve numerous biomedical tasks, can cross membranes, or reach intracellular targets. The role of peptides in bio-processes can hardly be mimicked by other chemical substances. The article is divided into independent sections, which are related to either the progress in short peptide-based theranostics or the problems posing challenge to bio-medicine. In particular, the SWOT analysis of short peptides, their relevance in therapies of diverse diseases, improvements in (bio)synthesis platforms, advanced nano-supramolecular technologies, aptamers, altered peptide ligands and in silico methodologies to overcome peptide limitations, modern smart bio-functional materials, vaccines, and drug/gene-targeted delivery systems are discussed.     

A chelation-assisted transformation: synthesis of maleimides by the Rh-catalyzed carbonylation of alkynes with pyridin-2-ylmethylamine

The reaction of alkynes 1 with CO and pyridin-2-ylmethylamine (2) in the presence of Rh4(CO)12/P(OEt)3 results in the incorporation of two molecules of CO leading to maleimide derivatives 3. The coordination of the pyridine nitrogen in 2 to a rhodium center is essential for the reaction to proceed.     

Quark confinement physics from quantum chromodynamics

We show the construction of the dual superconducting theory for the confinement mechanism from QCD in the maximally abelian (MA) gauge using the lattice QCD Monte Carlo simulation. We find that essence of infrared abelian dominance is naturally understood with the off-diagonal gluon mass m_off ≈- 1.2GeV induced by the MA gauge fixing. In the MA gauge, the off-diagonal gluon amplitude is forced to be small, and the off-diagonal gluon phase tends to be random. As the mathematical origin of abelian dominance for confinement, we demonstrate that the strong randomness of the off-diagonal gluon phase leads to abelian dominance for the string tension. In the MA gauge, there appears the macroscopic network of the monopole world-line covering the whole system. We investigate the monopole-current system in the MA gauge by analyzing the dual gluon field B_μ. We evaluate the dual gluon mas as m_B = 0.4 0.5GeV in the infrared region, which is the lattice-QCD evidence of the dual Higgs mechanism by monopole condensation. Owing to infrared abelian dominance and infrared monopole condensation, QCD in the MA gauge is describable with the dual Ginzburg-Landau theory.     

Mechanistic studies of the photocatalytic oxidation of trichloroethylene with visible-light-driven N-doped TiO2 photocatalysts

Visible-light-driven TiO2 photocatalysts doped with nitrogen have been prepared as powders and thin films in a cylindrical tubular furnace under a stream of ammonia gas. The photocatalysts thus obtained were found to have a band-gap energy of 2.95 eV. Electron spin resonance (ESR) under irradiation with visible light (lambda > or = 430 nm) afforded the increase in intensity in the visible-light region. The concentration of trapped holes was about fourfold higher than that of trapped electrons. Nitrogen-doped TiO2 has been used to investigate mechanistically the photocatalytic oxidation of trichloroethylene (TCE) under irradiation with visible light (lambda > or = 420 nm). Cl and O radicals, which contribute significantly to the generation of dichloroacetyl chloride (DCAC) in the photocatalytic oxidation of TCE under UV irradiation, were found to be deactivated under irradiation with visible light. As the main by-product, only phosgene was detected in the photocatalytic oxidation of TCE under irradiation with visible light. Thus, the reaction mechanism of TCE photooxidation under irradiation with visible light clearly differs markedly from that under UV irradiation. Based on the results of the present study, we propose a new reaction mechanism and adsorbed species for the photocatalytic oxidation of TCE under irradiation with visible light. The energy band for TiO2 by doping with nitrogen may involve an isolated band above the valence band.     

H2O2 Oxidation by Ce(IV) Contained Weakley-Type Heteropolyoxometalate for Various Alcohols

Catalytic activity of Ce(IV) contained Weakley-type heteropoly-oxometalate for the H₂O₂ oxidation of primary and secondary alcohols was evaluated for the first time. It was found that this catalyst exhibited a mild and thus quite selective activity, especially for benzylalcohols.     

Product selectivity control induced by using liquid-liquid parallel laminar flow in a microreactor

Product selectivity control based on a liquid-liquid parallel laminar flow has been successfully demonstrated by using a microreactor. Our electrochemical microreactor system enables regioselective cross-coupling reaction of aldehyde with allylic chloride via chemoselective cathodic reduction of substrate by the combined use of suitable flow mode and corresponding cathode material. The formation of liquid-liquid parallel laminar flow in the microreactor was supported by the estimation of benzaldehyde diffusion coefficient and computational fluid dynamics simulation. The diffusion coefficient for benzaldehyde in Bu(4)NClO(4)-HMPA medium was determined to be 1.32 × 10(-7) cm(2) s(-1) by electrochemical measurements, and the flow simulation using this value revealed the formation of clear concentration gradient of benzaldehyde in the microreactor channel over a specific channel length. In addition, the necessity of the liquid-liquid parallel laminar flow was confirmed by flow mode experiments.