Mechanical characterization of sol–gel epoxy-silylatedhyperbranched poly(ethyleneimine) coatings by meansof Depth Sensing Indentation methods

A series of hybrid epoxy-silica coatings were prepared from a synthesized hyperbranched poly(ethyleneimine) with ethoxysilyl groups at the chain ends and diglycidylether of bisphenol A in different proportions. The curing procedure was based in a first sol-gel reaction performed at 80 °C in a humid chamber followed by the anionic homopolymerization of epoxides initiated by 1-methylimidazole in an oven at 180 °C. The prepared coatings were characterized mechanically by means of Depth Sensing Indentation technique. The influence of physical ageing on indentation hardness has been evaluated. The kinetic of the delayed depth recovery has been analyzed using the phenomenological so-called Kohlrausch-Williams-Watts relaxation function. It has been found that silylated hyperbranched poly(ethyleneimine) improves simultaneously the mechanical coating performance and the elastic recovery.Postprint (author's final draft

Genome-wide analysis of the emigrant family of MITEs: amplification dynamics and evolution of genes in Arabidopsis thaliana

MITEs are structurally similar to defective class II elements but their high copy number and the size and sequence conservation of most MITE families suggest that they can be amplified by a replicative mechanism. Here we present a genome-wide analysis of the Emigrant family of MITEs from Arabidopsis thaliana. In order to be able to detect divergent ancient copies and low copy number subfamilies with a different internal sequence we have developed a computer program (http://www.lsi.upc.es/~alggen) that allows looking for Emigrant elements based solely on its TIR sequence. Our results show that different bursts of amplification of one or very few active, or master, elements have occurred at different times during Arabidopsis evolution, with an insertion dynamics similar to that of some SINEs. The analysis of the insertion sites of the Emigrant elements show that, although Emigrant elements tend to integrate far from ORFs, the elements inserted within or close to genes are preferentially maintained during evolution.Postprint (published version

Robust regression models for predicting the lean meat proportion of lambs carcasses

The aim of this study was to develop and evaluate robust regression models for predicting the carcass composition of lambs. One hundred and twenty lambs (34 females and 86 males) were slaughtered and their carcasses were cooled for 24 hours. The subcutaneous fat thickness (C12) was measured between the 12th and 13th rib, and the left side of carcasses was dissected and the proportions of lean meat (LMP) was calculated. A multiple regression model was fitted using robust regression (RR) methods, and the results were compared to ordinary least squares (OLS) estimates. For RR methods, the Bisquare and Welsch weighting functions were used, and model fitting quality was evaluated by the following statistics: the root mean square error (RMSE), the median absolute deviation (MAD), the mean absolute error (MAE), and the coefficient of determination (R2). The parameters obtained by RR presented lower standard error for C12 measurement (decreases by 12% when compared with OLS estimates). The RR methods or weighted least squares methods represents a good alternative to OLS approach for modelling the LMP of lambs carcass. In this study, the Bisquare weighting method presented the best results, however other weighting functions are available and should be tested and compared in the near future.info:eu-repo/semantics/publishedVersio

Thermal curing of an epoxy-anhydride system modified with hyperbranched poly(ethylene imine)s with different terminal groups

New hyperbranched polymers (HBP) have been synthesized by reaction of a poly(ethylene imine) with phenyl and t-butyl isocyanates. These HBPs have been characterized by 1H-NMR (nuclear magnetic resonance of hydrogen) and Fourier transform infrared spectroscopy. Their influence on the curing and properties of epoxy-anhydride thermosets has been studied by different techniques: differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and thermogravimetry (TG). The curing kinetics has been studied with DSC. Integral isoconversional method and the S ¿ esta´k–Berggren model have been used to determine the activation energy and the frequency factor. The kinetic parameters are very similar for all the studied systems at the middle stage of the process, but changes are observed at the beginning and at the end of the process when these modifiers are used. The HBPs reduce the glass transition temperature of the cured materials. In addition, from the DMA analysis it can be seen that the HBP modifier obtained from phenyl isocyanate hardly changes the storage modulus, but the obtained ones from t-butyl isocyanate decrease it. TG analysis reveals a decrease in the onset temperature of the degradation process upon addition of the HBPs.Postprint (author's final draft

Synthesis of 1,2,3-triazole functionalized hyperbranched poly(ethyleneimine) and its use as multifunctional anionic macroinitiator for diglycidyl ether of bisphenol A curing

Hyperbranched poly(ethyleneimine) (PEI) has been modified by the addition of propargyl acrylate following a Michael addition reaction. On this polymer (PEI-yne) a copper (I)-catalyzed azide alkyne cycloaddition (CuAAC) has been performed to obtain a multifunctional triazole initiator (PEI-TA). After structural and thermal characterization, this polymer has been used in different proportions as anionic multifunctional macroinitiator in diglycidyl ether of bisphenol A (DGEBA) homopolymerization. The curing process has been studied by calorimetry and the thermosets obtained have been thermally characterized and compared with thermosets prepared by using 1-methylimidazole (1-MI) as standard initiator. The electron microscopy inspection of the fracture surfaces of the new materials prepared shows the formation of submicrometer particles that should enhance toughness characteristics, changing smooth fracture surfaces in 1-MI initiated materials to multi-planar surface with tortuous and thicker cracks.Postprint (author's final draft

Microbiology and biochemistry of cheeses with appélation d’origine protegée and manufactured in the Iberian Peninsula from ovine and caprine milks

To support legal protection with objective technical data and to promote enforcement of high quality standards a few European countries have created Appe´lation d’Origine Protege´es. This paper reviews and updates fundamental and applied aspects encompassing microbiological and biochemical characteristics of traditional cheeses with Appe´lation d’Origine Protege´emanufactured in the Iberian Peninsula from ovine, caprine, or both milks. Ovine and caprine cheeses with Appe´lation d’Origine Protege´e from Portugal and Spain can be divided into four distinct groups based on milk source and rennet type: 1) Azeita˜ o, Castelo Branco, E´ vora, Nisa, Serpa, Serra da Estrela, and La Serena cheeses are manufactured with raw ovine milk and coagulated via plant rennet; 2) Terrincho, Idiaza´ bal, Manchego, Roncal, and Zamorano cheeses are manufactured with raw ovine milk and coagulated via animal rennet; 3) Cabra Transmontano and Majorero are manufactured with raw caprine milk and coagulated via animal rennet; and 4) Amarelo da Beira Baixa, Picante da Beira Baixa, and Rabac˛al are manufactured with mixtures of raw ovine and caprine milks and coagulated via animal rennet. (Key words: dairy foods, enzyme, microflora, Mediterranean) Abbreviation key:AOP = Appe´lation d’Origine Protege ´e, FA = fat acidity, LAB = lactic acid bacteria, TN = total nitrogen, WSN = water-soluble nitrogen, WSP = water-soluble peptides

Large critical current density improvement in Bi-2212 wires through groove-rolling process

Recently the interest about Bi-2212 round wire superconductor for high magnetic field use has been enhancing despite the fact that an increase of the critical current is still needed to boost its successful use in such applications. Recent studies have demonstrated that the main obstacle to current flow, especially in long wires, is the residual porosity inside these Powder-In-Tube processed conductors which develops in bubbles-agglomeration when the Bi-2212 melts. Through this work we tried to overcome this issue acting on the wire densification by changing the deformation process. Here we show the effects of groove-rolling versus drawing process on the critical current density JC and on the microstructure. In particular, groove-rolled multifilamentary wires show a JC increased by a factor of about 3 with respect to drawn wires prepared with the same Bi-2212 powder and architecture. We think that this approach in the deformation process is able to produce the required improvements both because the superconducting properties are enhanced and because it makes the fabrication process faster and cheaper