Oxybromination of Ethynylbenzene Catalysed by Molybdenum Complexes in Organic Solvent and in Ionic Liquids

The molybdenum(VI)‐catalysed oxybromination of ethynylbenzene was performed with hydrogen peroxide as oxidant and potassium bromide as source of bromine, in a two‐phase water/solvent system, where solvent was either dichloromethane or an ionic liquid. The selectivity was toward 1,2‐dibromostyrene when performed in water/dichloromethane. In ionic liquids better yields and shorter reaction times were obtained that, together with the complete ethynylbenzene conversion and the preferred formation of α,α‐dibromoacetophenone, make the reaction synthetically useful.     

The Anisotropy of Young's Modulus in Bones

In this paper, yet another method for evaluating the elastic modulus for human bones is introduced and investigated. This method adopts the Jankowski and Tsakalakos strain energy function in which, the Born-Mayer energy term is the predominant term for calculations the elastic constants. By taking accounts the directional aspects of the spatial structure of bones, we obtain different values for the Young's modulus depending on the direction of the applied force with respect to the material's structure. The inverse problem analyzed in this paper is solved by inversion of the experimental data. An efficient stopping criterion is adopted to cease the iterative process in order to retrieve stable numerical solutions. The numerical implementation of the aforementioned method is realized by employing a genetic algorithm.     

Highly Enantioselective Copper‐Phosphoramidite‐Catalyzed Conjugate Addition of Dialkylzinc Reagents to Acyclic α,β‐Unsaturated Imides

A new and practical way to introduce an alkyl fragment in the β‐position of aliphatic carboxylic acid derivatives with high enantioselectivities by the use of a commercially available chiral ligand is reported. N‐Acylpyrrolidinones, as simple derivatives of an α,β‐unsaturated carboxylic acid, were found to be the substrates of choice featuring good reactivity and high enantioselectivities (up to >99% ee).     

Modern perspectives in supercomputer-aided microwave circuit design

The computer-aided simulation and design of microwave integrated circuits often leads to large-size numerical jobs, especially for modern multiple-device MMIC subsystems such as distributed mixers and amplifiers. When this is the case, the use of large computer systems such as vector processors may become very attractive, because of the dramatic reduction of wall-clock time and of the related improvement of cost-to-performance ratio. This paper discusses the application of supercomputers to the solution of a number of such advanced microwave circuit CAD problems. An overview of the performance of general-purpose vectorized algorithms such as system solvers and Fast Fourier Transforms is first presented, in order to give a feeling of the potential of this class of machines in microwave CAD applications. Then a few typical microwave engineering problems are specifically addressed, including the statistical design (yield optimization) of linear circuits, the analysis of nonlinear circuits under multitone excitation, and the optimization of ultrabroadband nonlinear subsystems. In each case, a possible vectorization strategy is studied in depth, and the structure and performance of a specific highly vectorized algorithm are described in detail.     

Modulation of the hepatic CYP1A1 system in the marine fish Gobius niger, exposed to xenobiotic compounds

Anthropogenic chemicals in the aquatic environment are known to cause reproductive disturbances in vertebrate and invertebrate organisms by interfering with the endocrine systems. Large efforts have recently been devoted to dissect the mechanisms of action of xenobiotics in aquatic species, with the ultimate aim of detecting and controlling the effects of chemical exposure on the aquatic ecosystem and humans. In the present paper, males of a marine species, the black goby (Gobius niger), were treated with estrogenic and dioxin-like compounds commonly discharged into the environment from industry, agriculture, and urban waste such as nonylphenol (NP) and beta-naphthoflavone (beta-NF). Their effects were compared with those induced by estradiol (E2), analyzing the expression of biomarkers commonly used in ecotoxicological studies such as vitellogenin (VTG) and cytochrome P4501A1. The treatment with NP induced the synthesis of the female specific protein VTG in males, showing its estrogenic activity. NP and E2 lowered cytochrome P4501A1 basal levels while beta-NF determined a significant rise of its expression. The detoxification pathway was investigated, and the most relevant finding of this paper was the evidence that cytochrome P4501A1 inhibition by estrogen and estrogen-like compounds is mediated through the activation of the aryl hydrocarbon receptor repressor.     

Quantitative detection of Secale cereale by real-time PCR amplification

Wheat, barley, rye free diet is required to control coeliac disease and therefore adequate analytical tools are necessary to check gluten-free products. At the moment, official analytical methods are based on immunochemical assays for gliadin detection. However, DNA-based methods for detection of specific sequences have been extensively proposed as alternative to the protein-based ones, e.g. for transgenic contamination analysis. The aim of this work has been to develop an alternative quantification method for rye-content evaluation in raw materials and processed food based on real-time PCR approach using both SYBR green detection system and TaqMan fluorogenic probe.     

A stochastic model of damage accumulation in complex microstructures

A statistical approach for modeling fracture in brittle materials is presented. In particular, a microstructural-based finite element code called OOF is used in conjunction with a stochastic representation of failure that relies on the Weibull law. The OOF code, which maps materials microstructures onto finite element meshes, enables to calculate the local stress states; these stresses are used along with the statistical criterion for brittle fracture in order to determine microcrack formation and propagation. Computer simulations are performed on several microstructures of different materials types, e.g., laminates, particulate composites and polycrystals. The damage accumulation due to microcracking is characterized by the stereological measure of failed material and is investigated in order to assess the effect of microstructural features on the failure mechanism. Moreover, the approach allows to analyze the influence of the characteristic parameters for brittle materials on damage evolution.     

Stoichiometry of recombinant heteromeric glycine receptors revealed by a pore-lining region point mutation

Heteromeric glycine receptors mediate synaptic inhibition in the caudal areas of the adult mammalian central nervous system (CNS). These channels resemble other receptors in the nicotinic superfamily in that they are pentamers, but may differ in that they contain alpha and beta subunits in a 3:2 rather than a 2:3 ratio. Evidence in favor of a 3alpha:2beta stoichiometry of heteromeric glycine receptors comes from biochemical data and from the expression of chimeric subunits. We investigated this question using a potentially more direct approach and mutated the highly conserved hydrophobic residues in the middle (position 9') of the pore-lining domain. This mutation increases agonist potency in all channels in the nicotinic superfamily and its effects are in first approximation proportional to the number of mutant subunit incorporated into the receptor. We expressed in HEK 293 cells wild-type glycine alpha1beta receptors or receptors bearing the 9' mutation on either the alpha or the beta subunit, using an alpha:beta plasmid ratio of 1:40 in the transfection. This resulted in negligible levels of contamination by homomeric alpha1 receptors, as proven by low picrotoxin potency and by the extreme rarity of high conductances in single channel recording. Our data show that the effects of the 9' mutation on the receptor sensitivity to glycine were more marked when the alpha subunit bore the mutation. The magnitude of the leftward shift in the agonist dose-response curve for the two mutant combinations was in agreement with a subunit stoichiometry of 3alpha:2beta.     

Characterization of pulsed laser deposited zinc oxide

The pulsed laser deposition of zinc oxide films (ZnO) has been studied as a function of laser wavelength, and substrate temperature. Optical emission spectroscopy of the laser produced plume was used to characterize the deposition process. The deposited films were characterized by X-ray diffractometry, Auger electron spectroscopy, and scanning electron microscopy. Highly textured (002) ZnO films deposited at substrate temperatures of 300 °C with laser wavelengths of 532 nm and 248 nm. However, the energy fluence of 248 nm radiation controls the degree of texturing, allowing highly textured films to be deposited at room temperature.