Synthesis of NiO Crystals Exposing Stable High-Index Facets

Metal oxides exposing high-index facets are potentially impactful in catalysis and adsorption processes owing to under-coordinated ions and polarities that alter their interfacial properties compared to low-index facets. Here, we report molten-salt syntheses of NiO particles exposing a variety of crystal facets. We show that for a given anion (nitrate or chloride), the alkali cation has a notable impact on the formation of crystals exposing {311}, {611}, {100}, and {111} faces. Based on a parametric analysis of synthesis conditions, we postulate that the crystallization mechanism is governed by the formation of growth units consisting of Ni^II complexes whose coordination numbers are determined by temperature and the selection of anion (associated to the coordination sphere) and alkali cation (associated with the outer coordination sphere). Notably, our findings reveal that high-index facets are particularly favored in chloride media and are stable under prolonged periods of catalysis and steaming.     

Density functional theory study on mechanisms of epoxy‐phenol curing reaction

A comprehensive picture on the mechanism of the epoxy‐phenol curing reactions is presented using the density functional theory B3LYP/ 6‐31G(d,p) and simplified physical molecular models to examine all possible reaction pathways. Phenol can act as its own promoter by using an addition phenol molecule to stabilize the transition states, and thus lower the rate‐limiting barriers by 27.0–48.9 kJ/mol. In the uncatalyzed reaction, an epoxy ring is opened by a phenol with an apparent barrier of about 129.6 kJ/mol. In catalyzed reaction, catalysts facilitate the epoxy ring opening prior to curing that lowers the apparent barriers by 48.9–50.6 kJ/mol. However, this can be competed in highly basic catalysts such as amine‐based catalysts, where catalysts are trapped in forms of hydrogen‐bonded complex with phenol. Our theoretical results predict the activation energy in the range of 79.0–80.7 kJ/mol in phosphine‐based catalyzed reactions, which agrees well with the reported experimental range of 54–86 kJ/mol. © 2014 Wiley Periodicals, Inc.     

Measurement of isomeric yield ratios for the natHo(γ,xn)164m,g;162m,gHo reactions in the bremsstrahlung energy region from 45 to 65 MeV

We have measured the isomeric yield ratios for the ^164m,gHo and the ^162m,gHo isomeric pairs formed via photonuclear reactions ¹⁶⁵Ho(γ,n)^164m,gHo and ¹⁶⁵Ho(γ,3n)^162m,gHo in the bremsstrahlung energy region from 45 to 65 MeV in steps of ?E = 5 MeV by the activation method. The induced γ-activities of the irradiated holmium foils were measured by a coaxial high-purity germanium detector coupled to a PC-based multichannel analyzer. In order to improve the accuracy of the experimental results the necessary corrections were made. The experimental results at bremsstrahlung energies of 45, 50, 55, 60, and 65 MeV are 0.408 ± 0.027, 0.413 ± 0.027, 0.427 ± 0.029, 0.452 ± 0.032, and 0.448 ± 0.031 for the ^164m,gHo isomeric pair, and 0.587 ± 0.041, 0.624 ± 0.044, 0.652 ± 0.045, 0.637 ± 0.045, and 0.668 ± 0.046 for the ^162m,gHo isomeric pair, respectively. The present results are the first measurements at bremsstrahlung energies just above the giant dipole resonance region. The obtained results confirm the dependence of isomeric ratios on the incident photon energy as observed in some earlier experiments.     

p47phox, the phagocyte NADPH oxidase/NOX2 organizer: structure, phosphorylation and implication in diseases

Phagocytes such as neutrophils play a vital role in host defense against microbial pathogens. The anti-microbial function of neutrophils is based on the production of superoxide anion (O₂^•-), which generates other microbicidal reactive oxygen species (ROS) and release of antimicrobial peptides and proteins. The enzyme responsible for O₂^•- production is called the NADPH oxidase or respiratory burst oxidase. This multicomponent enzyme system is composed of two transmembrane proteins (p22phox and gp91phox, also called NOX2, which together form the cytochrome b₅₅₈) and four cytosolic proteins (p47phox, p67phox, p40phox and a GTPase Rac1 or Rac2), which assemble at membrane sites upon cell activation. NADPH oxidase activation in phagocytes can be induced by a large number of soluble and particulate agents. This process is dependent on the phosphorylation of the cytosolic protein p47phox. p47phox is a 390 amino acids protein with several functional domains: one phox homology (PX) domain, two src homology 3 (SH3) domains, an auto-inhibitory region (AIR), a proline rich domain (PRR) and has several phosphorylated sites located between Ser303 and Ser379. In this review, we will describe the structure of p47phox, its phosphorylation and discuss how these events regulate NADPH oxidase activation.     

Surgical case scheduling as a generalized job shop scheduling problem

Surgical case scheduling allocates hospital resources to individual surgical cases and decides on the time to perform the surgeries. This task plays a decisive role in utilizing hospital resources efficiently while ensuring quality of care for patients. This paper proposes a new surgical case scheduling approach which uses a novel extension of the Job Shop scheduling problem called multi-mode blocking job shop (MMBJS). It formulates the MMBJS as a mixed integer linear programming (MILP) problem and discusses the use of the MMBJS model for scheduling elective and add-on cases. The model is illustrated by a detailed example, and preliminary computational experiments with the CPLEX solver on practical-sized instances are reported.     

Bounds for the Effective Elastic Properties of Completely Random Planar Polycrystals

Bounds have been developed for the elastic moduli of completely random planar polycrystals, the shape and crystalline orientations of the constituent grains of which are supposed to be uncorrelated. Explicit results for the aggregates of orthotropic crystals are demonstrated. This revised version was published online in August 2006 with corrections to the Cover Date.