Using Conveniently Designed α‐Amino Ketones in Michael Reactions under Iminium Catalysis: Enantioselective Synthesis of γ‐Lactams and γ‐Amino‐δ‐keto Esters

The behaviour of aminoacetophenones as Michael donors in catalytic enantioselective Michael reactions with α,β‐unsaturated aldehydes under iminium activation has been studied. These compounds react with each other in the presence of catalytic amounts of a chiral secondary amine through a Michael/hemiaminal formation cascade process which proceeds with high yields and enantiocontrol. Elaboration of these adducts by oxidation allows the easy access to chiral disubstituted γ‐lactams and other synthetically useful chiral building blocks such as γ‐amino‐δ‐keto esters or β‐substituted δ‐oxoamides are accessible from the obtained adducts by simple transformations.     

Aspects for untangling cross‐layer design and policy support

Programming language concepts have inspired some networking design decisions. For example, concepts such as object encapsulation and interface invocation have been borrowed, at the time of their adoption, from an already well established object oriented programming paradigm. The authors suggest in this paper that it may be time again to revisit emerging software engineering programming paradigms to learn from them. More specifically, this paper discusses the practical tangling problem, embedded in conventional layer‐coupling (linking) network software design and highlighted by recent research proposals for cross layer design. The adopted solution is based on the aspect‐oriented programming paradigm. We show its programming efficiency, limitations and role in the seamless enforcement of multiple policy scenarios while emphasizing little design changes. Copyright © 2012 John Wiley & Sons, Ltd.     

Structures and morphologies of in situ polymerized blends of PMMA and ASA

Blends of poly(methyl methacrylate), PMMA, and the elastomer ASA, a graft copolymer based on poly(acrylonitrile‐co‐styrene) (SAN) and acrylic rubber, were prepared by in situ polymerization and characterized according to structural, mechanical, thermal, and morphological properties. The polymerization conditions, such the presence or absence of a chain transfer agent, stirring and an inert atmosphere, influence the morphological and structural properties of the blends. In spite of the evidences of the partial miscibility between PMMA and SAN phase of the ASA, the blends are heterogeneous and present a complex morphology. The morphology of some PMMA‐ASA blends is made up of an elastomeric dispersed phase in a glassy matrix, with a possible inclusion of the matrix in the elastomeric domains. The selective extraction of the blend components and infrared spectroscopy showed that crosslinking and/or grafting reactions occur on ASA chains during MMA polymerization. The syndiotacticity of PMMA obtained in the presence of ASA increases with the amount of ASA, due to possible interactions between the carbonyl groups of PMMA and the nitrile or phenyl groups of the SAN copolymer. The mechanical properties of the blends were influenced by the compositions of the blends and mainly by the conditions of polymerization. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Drying of Turnip Seeds with Microwaves in Fixed and Pulsed Fluidized Beds

This article presents experimental and modeled drying kinetics of turnip seeds as a function of the type of air-particle contact (fixed bed, pulsed fluidized bed), humidity of the air, and three levels of microwave irradiation. The effects of those factors on the drying time required to reach a moisture content of 0.1 kg/kg d.b. were determined with an experimental design of 12 experiments by using the software Statgraphics. It was found that in drying, a significant factor was the application of microwaves to a pulsed fluidized bed. The effect of the humidity of the air only became noticed when the moisture contents of the seeds was below 0.2 kg/kg d.b. The simplified variable diffusivity model (SVDM) gave the least deviations for the experimental data. The effective diffusivity values determined in this work are similar to those informed in the literature for experiments without microwave application. The application of microwaves in combination with pulsed fluidization of the turnip seeds resulted in a fourfold increase of the effective diffusivity.     

Paste Residence Time in a Spouted Bed Dryer. I: The Stimulus-Response Methodology

The stimulus response methodology was evaluated in an experimental study conducted to measure NaCl solution residence time distributions in a spouted bed dryer of inert particles. The influence of tracer volume, concentration, and injection mode upon the measured mean residence time and residence time distribution was determined following experimental design techniques. The injection mode showed no significant effect on residence times, whereas tracer volume and concentration had significant effects at the levels of 1 and 5%, respectively, under the conditions chosen initially. The steepest ascent and factorial design methods were applied to determine the range in parameters for optimum stimulus response. The procedure repeated for a polymeric paste showed similar results. However, the results also showed that care must be exercised when using the stimulus response technique and the optimum injection conditions must be determined. The procedure presented in this study may be adopted in future investigations of paste residence time distributions in spouted bed dryers of inert bodies.     

Brightness Improvement Of Douglas Fir Thermomechanical Pulp By Edta And Ascorbic Acid Treatments On Chips

This investigation studies the use of Douglas fir wood as feedstock for thermomechanical pulp (THP). Douglas fir wood extractives include flavonoids and other polyphenolic compounds, which make the pulp susceptible to discolouration. Pulp darkening is promoted by the formation of metal-chelates and phenolic oxidation products. The effectiveness of various wood pretreat- ments to prevent the discoloration of polyphenolic extractives in Douglas fir wood was investigated in lab-scale experiments. Iron- mediated brightness losses (up to 5.1% ISO) could be prevented by wood pretreatment with 0.2% EDTA. Treatment of wood meal slurries at temperature levels comparable to those applied in thermo- mechanical pulping caused wood discoloration due to polyphenol oxidation. The brightness losses could be reduced by the addition of 0.5% ascorbic acid. The anti-oxidizing agent was more effective with sapwood compared to heartwood. EDTA pretreatment allowed an increase in the proportion of heartwood from 12% to 39% (w/w) that could be tolerated as feedstock for the production of dithionite bleached TMP with a brightness of 60% ISO. Wood chip impregnation with both EDTA and ascorbic acid only proved advantageous over EDTA alone in Douglas fir samples consisting almost exclusively of sapwood.     

The electrical properties of Ba1-x SrxTiO3 thin films grown by sputter deposition

Abstract

Ba_1-x Sr_xTiO₃ (BST) thin films were deposited by reactive rf-magnetron sputtering onto Si substrates. The influence of the deposition parameters such as temperature and oxygen ambient on the dielectric constant of the films is presented. BST films deposited at 450°C and optimum conditions exhibited a dielectric constant of approximately 200 at frequencies as high as 1GHz. In addition, the films were found to have leakage current densities of <0.1μAmp/cm² at fields of 5×10⁵V/cm. An extrapolated lifetime greater than 10 years was obtained from stress tests at elevated temperatures and fields. These films compared favorably with published data.     

Domain Wall Dynamics Near the Phase Transition in PZN-9%PT

To investigate the paraelectric–ferroelectric phase transition in relaxor Pb(Zn_1/3Nb_2/3)O₃-9% PbTiO₃, correlations and scaling relations were measured from the domain structure of single crystals near the Curie temperature using a multifractal analysis. The dynamics of the domain walls were observed in (100) platelets using polarized light microscopy. The complexity of the domain wall distribution was evaluated by means of its fractal dimension and singularity spectrum. The changes in the energy state of the samples are assessed by measuring changes of the spatial distribution of the walls as a function of temperature; this can be used to estimate the specific heat.     

Effects of Probiotic Lactobacillus gasseri Strains of Breast-Fed Infant in a Murine Model

The ingestion of probiotic lactic acid bacteria has been evaluated and noted that it has an effect on the balance of desirable microbiota in the gastrointestinal tract. Lactobacillus gasseri demonstrates good survival in the gastrointestinal tract, and it has been associated with a variety of probiotic activities and roles, including the reduction of fecal mutagenic enzymes, the production of bacteriocins and the stimulation of macrophages immunomodulation. The aim of the study was to evaluate the effects of a pool of L. gasseri strains isolated from the feces of breastfed infants added in the human milk of healthy women. The milk was both pasteurized and unpasteurized, to verify the cell cytotoxicity of macrophages and to quantify the production of immunologic mediators such as IL-4, IL-6, IFN-γ, TNF-α, NO and oxygen intermediary compounds （H2O2）. The administration of raw human milk and pasteurized human milk to infants is a regular, encouraged practice in units of intensive therapy （UITs） and our present investigation verified the beneficial effect of addition of a pool of L. gasseri to pasteurized human milk （PHML）. Our results show that probiotic supplementation helped to maintain cell viability, reduced IL-6 and IFN-γ production and stimulated TNF-α, NO, H2O2, IL-4 production. Nevertheless, the results indicate that the addition of lactobacillus to human milk was not a determinant in the production of TNF-α. L. gasseri added to breast milk did not present a cytotoxic risk, and the addition ofL. gasseri to pasteurized milk of human milk bank would benefit newborns that depend on milk banks for the colonization of more desirable microbiota.     

Polyether ionophores residues in Minas Frescal cheese by UHPLC-MS/MS

ABSTRACT

An analytical method was developed and validated for the determination of three polyether ionophores (monensin, lasalocid, and salinomycin) in 60 samples of Brazilian Minas Frescal cheese by UHPLC-MS/MS. Linearity ranged from 1 to 8 μg kg^?1 for monensin and salinomycin, and from 0.50 to 4 μg kg^?1 for lasalocid. Limits of detection and quantitation were 0.50 μg kg^?1 and 1 μg kg^?1, respectively, for both monensin and salinomycin, and 0.25 μg kg^?1 and 0.50 μg kg^?1, respectively, for lasalocid. Recoveries were between 69% and 84% with coefficients of variation up to 16.28% for repeatability and 13.79% for intermediate precision. A total of 60 samples of Minas Frescal cheese were analysed and only monensin residues were found. Monensin was detected in 55% of the samples and quantified in 5 of them at mean levels varying from 1.00 to 1.73 μg kg^?1. The proposed method demonstrated the suitability for monitoring these substances in cheese.