Loewner chain and quasiconformal extension of some classes of univalent functions

ABSTRACT

In this article, we obtain quasiconformal extensions of some classes of conformal maps defined either on the unit disc or on the exterior of it onto the extended complex plane. Some of these extensions have been obtained by constructing suitable Loewner chains and others have been found by applying a well-known result.     

Preparation of triazolobenzodiazepine derivatives as Vasopressin V1a antagonists

This Letter describes the synthesis of a number of fused tricyclic and bicyclic triazolobenzodiazepines for the Vasopressin V1a antagonist programme.     

Mechanisms investigation of the WGSR catalyzed by single noble metal atoms supported on vanadium oxide clusters

The redox and carbonyl mechanisms of the water gas shift reaction (WGSR) catalyzed by the single noble metal (NM) atoms of Ru, Rh, Pd, Ag (from the 4d row) and Os, Ir, Pt, Au (from the 5d row) supported on vanadium oxide cluster ion V₂O₆⁺ have been firstly investigated through the density functional theory (DFT) calculations. Natural population analysis (NPA) shows NMs possess positive charges in the model systems and usually act as reactant molecule trapper and an effective electron store to accept or release electrons. The carbonyl mechanism avoiding the oxygen vacancy (O_v) formation and directing NM‐H bond cleavage is strongly preferred over the redox mechanism. Our computations identified single‐atom catalysts (SAC), especially RhV₂O₆⁺ and PdV₂O₆⁺ exhibit improved overall catalytic performance because of the lower rate‐control step activation barriers via the associate carbonyl mechanism. This work aims to provide some detailed insights into the effects of NM in bimetallic oxide clusters for WGSR at a molecular level, and serves as a starting point for further theoretical studies on the mechanisms of related SAC catalytic reactions.     

Laser field dependence of intersubband transition in inverse V‐shaped quantum wells

The electron energy levels and the envelope wave functions in inverse GaAs/AlGaAs V‐shaped quantum wells (QWs) are calculated using the transfer matrix method. The influence of applied electric and laser fields on the electronic distribution is investigated. In studied systems, a laser‐induced attenuation for anomalous electric polarization of the excited state is found. Also, an oscillator strength increasing under high‐frequency laser radiation is obtained. The results presented in this article can be useful for novel device applications based on the intersubband transitions of electrons. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011     

Fe2V4O13 Nanoparticles Based Electrochemical Sensor for the Simultaneous Determination of Guanine and Adenine at Nanomolar Concentration

A simple strategy has been proposed for the simultaneous quantification of guanine (GU) and adenine (AD) using Fe₂V₄O₁₃ nanoparticles (Fe₂V₄O₁₃ NPs) modified carbon paste electrode (Fe₂V₄O₁₃NPs/CPE) in phosphate buffer solution (PBS). The Fe₂V₄O₁₃ NPs were prepared by a simple solution combustion method where sucrose was used as a fuel. The electrochemical behavior of GU and AD at the electrochemical interface has been studied by using cyclic voltammetry (CV) and differential pulse stripping voltammetry (DPSV). The results illustrate that the Fe₂V₄O₁₃ NPs shows enhanced electrocatalytic activity and voltammetric response towards GU and AD. The proposed sensor showed linearity between the concentration 0.5 and 60 μM with limit of detection (LOD) 32 and 37 nM for GU and AD respectively. The sensitivity towards GU and AD were respectively found to be 1.393 and 1.851 μA/μM. Further, the proposed electrochemical sensor has been successfully employed to determine GU and AD contents in milk powder and calf thymus DNA samples.     

Enzymatic Formation of Indolactam Scaffold by C−N Bond-Forming Cytochrome P450 Oxidases in Teleocidin Biosynthesis

Teleocidins are potent protein kinase C activators, and possess a unique indole-fused nine-membered lactam structure. Teleocidin biosynthesis starts from the formation of a dipeptide by non-ribosomal peptide synthetase (NRPS), followed by oxidative C−N bond formation by a cytochrome P450 oxidase, reverse-prenylation by a prenyltransferase, and methylation-initiated terpene cyclization by a C-methyltransferase. This minireview focuses on recent research progress toward the elucidation of the molecular basis for the remarkable P450-catalyzed intramolecular C−N bond-forming reaction, which is challenging in synthetic chemistry, to generate the indolactam scaffold. In addition, precursor-directed biosynthesis with the promiscuous P450 enzymes led to the formation of a series of unnatural and novel molecular scaffolds, including a sulfur-substituted indolactam with a different conformation from that of indolactam V.     

Construction of Hierarchical Nanotubes Assembled from Ultrathin V3S4@C Nanosheets towards Alkali‐Ion Batteries with Ion‐Dependent Electrochemical Mechanisms

Ultrathin core–shell V₃S₄@C nanosheets assembled into hierarchical nanotubes (V₃S₄@C NS‐HNTs) are synthesized by a self‐template strategy and evaluated as general anodes for alkali‐ion batteries. Structural/physicochemical characterizations and DFT calculations bring insights into the intrinsic relationship between crystal structures and electrochemical mechanisms of the V₃S₄@C NS‐HNTs electrode. The V₃S₄@C NS‐HNTs are endowed with strong structural rigidness owing to the layered VS₂ subunits and interlayer occupied V atoms, and efficient alkali‐ion adsorption/diffusion thanks to the electroactive V₃S₄‐C interfaces. The resulting V₃S₄@C NS‐HNTs anode exhibit distinct alkali‐ion‐dependent charge storage mechanisms and exceptional long‐durability cyclic performance in storage of K⁺, benefiting from synergistic contributions of pseudocapacitive and reversible intercalation/de‐intercalation behaviors superior to those of the conversion‐reaction‐based Li⁺‐/Na⁺‐storage counterparts.