Switching of transmission resonances in a two-channels coupler: A Boundary Wall Method scattering study

In this work, we study the transmission characteristics of a two-channels coupler model system using the Boundary Wall Method (BWM) to determine the solution of the corresponding scattering problem of an incident plane wave. We show that the BWM provides detailed information regarding the transmission resonances. In particular, we focus on the case of single channel input aiming to explore the energy switching performance of the coupler. We show that the coupler geometry can be tailored to allow for the first transmission resonances to be predominantly transmitted on specific output channels, an important characteristic for the realization of logical operations.     

Charged silsesquioxane used as a vehicle for gold nanoparticles to perform the synthesis of catalyst xerogels

The water soluble charged silsesquioxane that contains the bridged 1,4-diazoniabicyclo[2.2.2]octane chloride group, was used as stabilizing agent and size controller in the synthesis of gold nanoparticles smaller than 15?nm in aqueous medium. The gold nanoparticle dispersion was converted in solid powder form by evaporation. This powder presented organized structure imposed by the presence of charged organic group, similar to organized structure already observed for pure silsesquioxane. The gold nanoparticles in solid powder form presented high storage stability for several months, at ambient conditions, and can be completely redispersed in water again. After redispersion, the optical properties of gold nanoparticles, observed by ultra-violet and visible spectroscopy, and their morphological characteristics, investigated by transmission electron microscopy, are preserved. The gold nanoparticle aqueous dispersion was used as a vehicle of nanoparticles in the synthesis of sol?Cgel silica based hybrid material. This xerogel was characterized by N₂ adsorption?Cdesorption isotherms, showing 260?m²g^?1, and it was applied in a satisfactory way as catalyst for p-nitrophenol reduction to p-aminephenol.     

Synthesis,characterization and assessment of the cytotoxic activity of Cu(II), Fe(III) and Mn(III) complexes of camphoric acid‐derived salen ligands

Novel Cu(II), Fe(III) and Mn(III) salen‐type metal complexes from (1R,3S)‐N,N′‐bis[salicylidene]‐1,3‐diamino‐1,2,2‐trimethylcyclopentane were synthesized and screened for their in vitro cytotoxic activity against three human cancer cell lines: melanoma, colorectal and breast. In vitro experiments carried out with the three metal complexes show that the copper complex exhibits the highest cytotoxic activity towards all cell lines studied, presenting IC₅₀ values of 3.32–6.71 μM. A significant improvement in the anti‐proliferative effect, by 20‐fold, is observed with this complex when compared with conventional chemotherapy. The relationship between structure, redox characteristics and biological activity in human cancer cell lines was evaluated for the most efficient Cu(II) complex and associated with theoretical calculations. Copyright © 2015 John Wiley & Sons, Ltd.     

Improvement in the predictivity of squeal simulations: Uncertainty and robustness

The objective of this paper is to improve the predictivity of squeal simulations by introducing uncertainty and robustness concepts during simulations. Complex eigenvalue analysis is a traditional way to detect numerically the unstable modes that can be associated with extensive vibration and noise pollution. This simulation, for which associated computational times are compatible with the design phase, is known to be insufficiently predictive. We first propose a complete strategy that relies on the integration of random fields into the contact interface, complex eigenvalue calculations, probabilistic analysis and a robustness criterion. Next, this strategy is applied to study the instabilities of a complete industrial brake system. Experimental comparisons highlight the efficiency of the improved squeal detection methodology.     

The cognitive demands of understanding the sample space

According to our analysis of cognitive demands, the concepts of classification, logical multiplication and ratio provide a basis for understanding sample space. These basic concepts develop during the elementary school years, which suggest that it is possible to teach elementary school children effectively about sample space. This hypothesis was tested in an intervention study, in which Grade 6 children (aged 10–11 years) were randomly assigned to one of three groups: a sample space group (SSG), a problem-solving group, and an unseen comparison group. The SSG showed significantly more progress than both comparison groups in three post-tests, including one given 2 months after the teaching had ended. We conclude that our analysis of the cognitive demands of sample space was supported and discuss the implications for mathematics education.     

A Facile Synthesis of α-Phenylchalcogeno(S,Se) α,β-Unsaturated Esters from Ethyl α-Bromo-α-phenylchalcogeno Acetates

Ethyl α-bromo-α-phenylseleno acetate 1 and ethyl α-bromo-α-phenylthio acetate 2 react with aldehydes in the presence of dibutyltelluride to give α-phenylchalcogeno-α,β-unsaturated esters, with Z preferential stereochemistry.     

REACTIONS OF N-(p-CHLOROSULFONYLPHENYL)MALEIMIDE

Abstract

N-Phenylmaltimide reacted with chlorosulfonic acid to give an excellent yield of the sulfonyl chloride (1), which with dimethylamine or aniline (2 equivs.) afforded the corresponding sulfonamides (2,3). However, use of more dimethylamine (4 equivs.) caused opening of the imido ring and addition to the double bond to yield the dimethylamide (12). Similar reaction with diethylamine in methanol resulted in nucleophilic ring-opening by the solvent leading to the methyl ester (13). Analogous reactions with morpholine, pyrrolidine and piperidine (3 equivs.) proceeded with addition and substitution to give 7–9. N-(p-chlorosulfonylphenyl)-3,4-dichloromaleimide (15) reacted with amines with substitution of both the 3- and sulfonyl chlorine atoms to give the sulfonamides (16–21).

3-Chloro-4-phenoxy-N-phenylmaleimide reacted with chlorosulfonic acid to give the bis-sultonyl chloride (22); condensation with dimethylamine caused displacement of the 4-(p-chlorosulfonyl-phenoxy) group to give 16. The various reactions are discussed and the structures of the products confirmed by microanalytical and spectroscopic data. The results of preliminary biological screening against 4 fungi and 2 enzymes are included.     

Fractionation of Protein Hydrolysates of Fish and Chicken Using Membrane Ultrafiltration: Investigation of Antioxidant Activity

In this work, chicken and fish peptides were obtained using the proteolytic enzymes α-Chymotrypsin and Flavourzyme. The muscle was hydrolyzed for 4 h, and the resulting peptides were evaluated. Hydrolysates were produced from Argentine croaker (Umbrina canosai) with a degree of hydrolysis (DH) of 25.9 and 27.6 % and from chicken (Gallus domesticus) with DH of 17.8 and 20.6 % for Flavourzyme and α-Chymotrypsin, respectively. Membrane ultrafiltration was used to separate fish and chicken hydrolysates from Flavourzyme and α-Chymotrypsin based on molecular weight cutoff of >1,000, <1,000 and >500, and <500 Da, to produce fractions (F1,000, F1,000–500, and F500) with antioxidant activity. Fish hydrolysates produced with Flavourzyme (FHF) and α-Chymotrypsin showed 60.8 and 50.9 % of peptides with a molecular weight of <3 kDa in its composition, respectively. To chicken hydrolysates produced with Flavourzyme and α-Chymotrypsin (CHC) was observed 83 and 92.4 % of peptides with a molecular weight of <3 kDa. The fraction that showed, in general, higher antioxidant potential was F1,000 from FHF. When added 40 mg/mL of FHF and CHC, 93 and 80 % of lipid oxidation in ground beef homogenates was inhibited, respectively. The composition of amino acids indicated higher amino acids hydrophobic content and amino acids containing sulfuric residues for FHF, which showed antioxidant potential.