Effective preparation of 5, 5'-(arylmethylene)bis(4-hydroxythiazole-2(3H)-one) in an aqueous fluoroalcohol solvent system under ultrasound irradiation at room temperature

A green and convenient approach for the synthesis of a series of 5,5'-(arylmethylene)bis(4-hydroxythiazole-2(3H)-one) by the reaction of aryl aldehydes, monochloroacetic acid and ammonium thiocyanate in water/trifluoroethanol(TFE) (1:1) under ultrasound irradiation at room temperature is described. This method provides several advantages such as environmental friendliness, shorter time, excellent yields, and simple work-up procedure.     

SBA‐15‐functionalized melamine–pyridine group‐supported palladium(0) as an efficient heterogeneous and recyclable nanocatalyst for N‐arylation of indoles through Ullmann‐type coupling reactions

SBA‐15‐functionalized melamine–pyridine group‐supported palladium(0) was found to serve as a heterogeneous and recyclable nanocatalyst for N‐arylation of indoles with aryl iodides under a low catalyst loading (0.3 mol% of Pd) through Ullmann‐type C? N coupling reactions. A variety of aryl iodides could be aminated to provide the N‐arylated products in good to excellent yields without the need of an inert atmosphere. Also, this catalyst was found to be an efficient system for the N‐arylation of other nitrogen‐containing heterocycles with aryl iodides. The heterogeneous palladium catalyst could be recovered by simple filtration of the reaction solution and reused for six cycles without significant loss in its activity. Copyright © 2015 John Wiley & Sons, Ltd.     

A convenient and chemoselective one-pot oxidation/Wittig reaction for the C2-homologation of carbohydrate-derived glycols

[reaction: see text] A simple and convenient one-pot protocol for the chemoselective C2-homologation of carbohydrate-derived glycols is described. The method comprises the chemoselective oxidation of the glycol to the corresponding hydroxyaldehyde and the subsequent Wittig alkenylation. In addition, the method does not need selective protective group manipulation, and it is safe, economical, fast (5 to 6 h), and bench-friendly. Its general utility is discussed.     

Arrowroot starch-based films incorporated with a carnauba wax nanoemulsion,cellulose nanocrystals,and essential oils: a new functional material for food packaging applications

Arrowroot starch (AA)-based films incorporated with a carnauba wax nanoemulsion (CWN), cellulose nanocrystals (CNCs), and essential oils (EOs) from Mentha spicata (MEO) and Cymbopogon martinii (CEO) were produced using the casting technique and then characterized in terms of their water barrier, tensile, thermal, optical, and microstructural properties and in vitro antifungal activity against Rhizopus stolonifer and Botrytis cinerea. Whereas the incorporation of CNCs decreased the moisture content and water vapor permeability of the AA/CWN/CNC film, the additional incorporation of either EO decreased the transparency and affected the microstructure of the AA/CWN/CNC/EO nanocomposites. MEO and CEO incorporation improved the thermal stability of the films and provided excellent protection against fruit-spoiling fungi. Because of their excellent barrier properties against fungal growth, water vapor permeability, and ultraviolet and visible light, these AA/CWN/CNC/EO films have promising potential for application as active food packaging or coating materials.

Graphic abstract

     

Arbitrary side observations in bandit problems

A bandit problem with side observations is an extension of the traditional two-armed bandit problem, in which the decision maker has access to side information before deciding which arm to pull. In this paper, essential properties of the side observations that allow achievability results with respect to optimal regret are extracted and formalized. The sufficient conditions for good side information obtained here admit various types of random processes as special cases, including i.i.d. sequences, Markov chains, deterministic periodic sequences, etc. A simple necessary condition for optimal regret is given, providing further insight into the nature of bandit problems with side observations. A game-theoretic approach simplifies the analysis and justifies the viewpoint that the side observation serves as an index specifying different sub-bandit machines.     

Filtering method in backlash phenomena analysis

The behavior of robotic manipulators with backlash is analyzed. Based on the pseudo-phase plane two indices are proposed to evaluate the backlash effect upon the robotic system: the root mean square error and the fractal dimension. For the dynamical analysis the noisy signals captured from the system are filtered through wavelets. Several tests are developed that demonstrate the coherence of the results.     

Optimal time to change premiums

The claim arrival process to an insurance company is modeled by a compound Poisson process whose intensity and/or jump size distribution changes at an unobservable time with a known distribution. It is in the insurance company’s interest to detect the change time as soon as possible in order to re-evaluate a new fair value for premiums to keep its profit level the same. This is equivalent to a problem in which the intensity and the jump size change at the same time but the intensity changes to a random variable with a know distribution. This problem becomes an optimal stopping problem for a Markovian sufficient statistic. Here, a special case of this problem is solved, in which the rate of the arrivals moves up to one of two possible values, and the Markovian sufficient statistic is two-dimensional. This work was partially supported by the US Army Pantheon Project and National Science Foundation under grant DMS-0604491.     

A note about teleparallel supergravity

The supersymmetric extension of teleparallel gravity is discussed. It is found that teleparallel supergravity is equivalent to the usual supergravity when the vierbein, the gravitino field and the connection are not identified with the component of the gauge potential, but are obtained taking the limit in (81), (83) and (84) of P. Salgado, S. del Campo, M. Cataldo, Phys. Rev. D 68, 024021 (2003). It is also shown that the successful formalism of Grignani-Nardelli permits one to obtain teleparallel-supergravity in (2 + 1) dimensions from (3 + 1)-dimensional teleparallel supergravity. Received: 11 May 2005, Published online: 6 October 2005 PACS: 04.65. + e     

Analysis of peptides and proteins affinity-bound to iron oxide nanoparticles by MALDI MS

Iron oxide nanoparticles modified with oleate have been employed for the extraction of peptides and proteins from aqueous solution before matrix-assisted laser desorption/ionization (MALDI) mass spectrometric (MS) analysis. Adsorption of peptides and proteins onto the nanoparticles were mainly through electrostatic attraction and hydrophobic interaction. The analyte-adsorbed iron oxide nanoparticles could be efficiently collected from solution using a magnet. No elution step was needed. With this preconcentration strategy, the lowest detectable concentration of angiotensin I, insulin, and myoglobin in 500 microL of aqueous solution were 0.1 nM, 0.1 nM, and 10.0 nM, respectively. In addition, the nanoparticles could extract the analytes from solution with a high content of salt and surfactant, thus eliminating suppression effect during MALDI MS analysis. This method was successfully applied to concentrate the tryptic digest products of cytochrome c. In addition, the tryptic digestion of cytochrome c can be directly conducted on the iron oxide nanoparticles.     

The fast multipole method on parallel clusters,multicore processors,and graphics processing units

In this article, we discuss how the fast multipole method (FMM) can be implemented on modern parallel computers, ranging from computer clusters to multicore processors and graphics cards (GPU). The FMM is a somewhat difficult application for parallel computing because of its tree structure and the fact that it requires many complex operations which are not regularly structured. Computational linear algebra with dense matrices for example allows many optimizations that leverage the regular computation pattern. FMM can be similarly optimized but we will see that the complexity of the optimization steps is greater. The discussion will start with a general presentation of FMMs. We briefly discuss parallel methods for the FMM, such as building the FMM tree in parallel, and reducing communication during the FMM procedure. Finally, we will focus on porting and optimizing the FMM on GPUs.