An efficient synthesis of LY544344·HCl: a prodrug of mGluR2 agonist LY354740

LY544344·HCl was efficiently prepared in two steps from LY354740. The key step highlighted the in situ masking of the carboxylic acid groups as trimethylsilyl esters to facilitate an effective acylation reaction.     

A bifurcation-based decohesion model for simulating the transition from localization to decohesion with the MPM

Based on recent experimental observations on the formation of localization before delamination, a bifurcation-based decohesion approach is proposed in this paper to simulate the transition from localization to decohesion involved in the delamination process of compressed films. The onset and orientation of discontinuous failure are identified from the discontinuous bifurcation analysis. A discrete constitutive model is then formulated based on the bifurcation analysis to predict the evolution of material failure as decohesion or separation of continuum. The Material Point Method, that does not employ fixed mesh-connectivity, is developed as a robust spatial discretization method to accommodate the multi-scale discontinuities involved in the film delamination. To demonstrate the potential of the proposed approach, a parametric study is conducted to explore the effects of aspect ratio and failure mode on the evolution of failure patterns under different boundary conditions, which provides a better understanding on the physics behind the film delamination process.     

Release and uptake of oxygen in mixed-conducting SOFC cathode materials measured by temperature-programmed methods

Oxygen uptake and release in A_1−aA′_aB_1−bB′_bO_3−δ perovskite-type oxides with A=La, Pr; A′=Sr; B=Fe, Mn, B′=Co was examined by means of temperature-programmed oxidation (TPO) and temperature-programmed reduction (TPR). The investigated powders were prepared by spray-drying and were annealed at 900 to 1300 °C. In the TPR profiles, two processes of oxygen release from these materials were observed. The first TPR peak was regarded as surface adsorption, while the second one was considered to result from oxygen bulk diffusion. The oxygen volumes involved and the activation energy for the oxygen diffusion were determined from the TPO and TPR profiles and varied between 0.53 and 2.2 eV for the ferrites and manganites, respectively. Paper presented at the 9th EuroConference on Ionics, Ixia, Rhodes, Greece, Sept. 15–21, 2002.     

Computing non‐Newtonian fluid flow with radial basis function networks

This paper is concerned with the application of radial basis function networks (RBFNs) for solving non‐Newtonian fluid flow problems. Indirect RBFNs, which are based on an integration process, are employed to represent the solution variables; the governing differential equations are discretized by means of point collocation. To enhance numerical stability, stress‐splitting techniques are utilized. The proposed method is verified through the computation of the rectilinear and non‐rectilinear flows in a straight duct and the axisymmetric flow in an undulating tube using Newtonian, power‐law, Criminale–Ericksen–Filbey (CEF) and Oldroyd‐B models. The obtained results are in good agreement with the analytic and benchmark solutions. Copyright © 2005 John Wiley & Sons, Ltd.     

N‐Linked Glycosyl Auxiliary‐Mediated Native Chemical Ligation on Aspartic Acid: Application towards N‐Glycopeptide Synthesis

A practical approach towards N‐glycopeptide synthesis using an auxiliary‐mediated dual native chemical ligation (NCL) has been developed. The first NCL connects an N‐linked glycosyl auxiliary to the thioester side chain of an N‐terminal aspartate oligopeptide. This intermediate undergoes a second NCL with a C‐terminal thioester oligopeptide. Mild cleavage provides the desired N‐glycopeptide.     

Fluorescence chemical sensor based on water‐soluble poly(p‐phenylene ethynylene)–graphene oxide composite for Cu2+

A chemical sensor for metal ions was fabricated based on a water‐soluble conjugated polymer–graphene oxide (GO) composite. Water‐soluble poly(p‐phenylene ethynylene) (PPE) with sulfonic acid side chain groups was used to prepare a very stable water‐soluble PPE–GO composite with strong π–π interactions in water. The relationship between the optical properties and metal ion sensing capability of the PPE–GO composite in aqueous solution was investigated. Addition of metal ions enhanced the fluorescence intensity of the composite, and, in particular, the composite enabled the fluorescence detection of Cu²⁺ in aqueous solutions with high selectivity and sensitivity. Therefore, this conjugated polymer–GO composite sensor system was found to be an effective turn‐on type chemical sensor for metal ions. Copyright © 2015 John Wiley & Sons, Ltd.     

Transient flow rate behaviour in an external natural convection boundary layer

A theoretical approach is proposed to investigate the transient dynamic behaviour of a free convection boundary layer-type flow. The set of continuity, momentum and energy equations are solved with the classical Boussinesq approximation using the Karman–Pohlhausen integral method. Applying a step variation of the uniform heat flux on a vertical wall, the boundary layer thickness and velocity profiles within the viscous layer, streamline patterns and volumetric flow rate are evaluated as a function of time. In addition, corresponding fully analytical asymptotic solutions are derived to be readily used in engineering applications.     

Coupling‐Reagent‐Free Synthesis of Dipeptides and Tripeptides Using Amino Acid Ionic Liquids

A general method for the synthesis of dipeptides has been developed, which does not require any coupling reagents. This method is based on the reaction of readily available HCl salts of amino acid methyl esters with tetrabutylphosphonium amino acid ionic liquids. The isolation procedure of stepwise treatment with AcOH is easy to carry out. The method was extended to the synthesis of tripeptide, tyrosyl‐glycyl‐glycine, present in IMREG‐1, also.     

Uniform Surface Oxidation of an Si Substrate by a Planar Modulated Inductively Coupled Thermal Plasma with Molecular Gas Feed

A planar type of inductively coupled thermal plasma (ICTP) with coil current modulation was adopted for large-area rapid surface oxidation of a substrate. The planar ICTP has been developed by the authors for large-area surface modification processing. In addition, coil current modulation was used to control the temperature and chemical reaction fields in the planar ICTP. Firstly, a fundamental study of the operation of the planar modulated ICTP with a substrate was carried out by measuring its electrical properties and the visible light emission in this work. Secondly, spectroscopic observations were carried out to investigate the effect of the coil current modulation on the radiation intensity distribution of spectral lines from the planar ICTP on the substrate. Thirdly, surface oxidation tests were made for Si substrates by irradiation of the planar modulated ICTP at different modulation frequencies and different duty factors. Oxide layer thickness distribution fabricated on the substrate was measured to study the lateral uniformity of the oxidation processing by the modulated planar ICTP. Finally, it was found that adoption of the coil modulation can improve the uniformity of the oxidation processing by the planar modulated ICTP.     

Adaptive Fourier tester for statistical estimation

Based on Takenaka–Malmquist (TM) system, a new nonparametric estimator for probability density function is proposed. The TM estimation method is completely different from the existent density estimation methods in that the estimator depends on an approximate system with poles in a complex plane. Compared with the classic Fourier estimator, the TM estimator will offer more flexibility and adaptivity for real data due to the poles and nonlinearity of the phase of TM system. We compare the TM estimator with kernel, wavelet, and spline estimators by simulations. It shows that the introduced TM estimator is a more promising method than the existing and commonly used methods. Copyright © 2016 John Wiley & Sons, Ltd.