Hydrolytic degree and antioxidant activity of purified casein characterised by different haplotypes (αs1-, β- and k-casein) after enzymatic hydrolysis with pepsin and enzymatic extract from Pleurotus eryngii

The aim of this study was to estimate the hydrolytic degree and antioxidant activity of purified casein characterised by different haplotypes (α_s1-, β- and k-casein) after in vitro digestion with two different enzymatic systems: pepsin from porcine gastric mucosa (EP) and a crude enzymatic extract from the edible mushroom Pleurotus eryngii. The used enzymes showed a different mode of casein catalysis with a consequent production of peptides of different antioxidant activity. The CN haplotype significantly influenced peptides production; in fact, the amino acid substitutions caused by genetic polymorphisms at the α_s1-, β- and k-CN loci influenced the sites of enzymatic cleavage and therefore the produced peptides. The above is evidenced by the different antioxidant activity found in the hydrolysates depending on the used enzymatic system, the CN haplotype, and the CN haplotype × enzymatic treatment interaction. The findings of this study are a perspective for the production of specific foods that exert a biological effect in addition to the nutritional one.     

Corticosteroids in liver and urine in Sicilian cattle by a LC-MS/MS method

The presence of corticosteroid residues was assessed in urine and liver samples from livestock of Sicily. A total of 630 bovine samples were collected from farms and slaughterhouses. The samples were analysed using solid-phase extraction (SPE) coupled with ultra-performance liquid chromatography tandem mass spectrometry (UHPLC–MS/MS). All the corticosteroids found were under the maximum residue limit imposed by Commission Regulation (EC) 37/2010. About 4% of liver samples showed dexamethasone levels above the limit of detection (LOD), with a mean of 1.5 ± 0.2 µg kg^?1. Betamethasone was found only in seven liver samples, with a mean of 1.6 ± 0.1 µg kg^?1. Furthermore, prednisolone and prednisone were found only in urine and liver samples from slaughterhouse, probably related to the high rate of stress for bovines. These results suggest good control practices adopted by Sicilian farms, able to ensure the quality of food products.     

Determination of contact points between workpiece and fixture elements as a tool for augmented reality in fixture design

Wireless Networks - Fixtures play a significant role in ensuring the quality of products in manufacturing engineering. The paper considers fork-type parts that have a complex spatial configuration...     

Effect of boron addition on the microstructure and mechanical properties of 6.5% V-5% W high speed steel

The effect of adding 0.04% additional boron to 6.5% V-5% W high speed steel was investigated. The microstructure characterization, phase identification, and carbide identification of the materials were performed using SEM/EDS and XRD. The cell size and carbide volume fraction were examined using image analysis software. The boron distribution was observed by PTA Boron Tracking. The addition of 0.04% more boron to a HSS alloy exerted a cell refining effect on the sample. The cell refinement of dendritic structures in the alloy containing boron may be attributed to the constitutional supercooling effect associated with the fairly small distribution coefficient for boron in iron. The addition of boron increases the bending strength of the material by more than 10%, as well as increasing its hardness.     

Importance of a Conserved Lys/Arg Residue for Ligand/PDZ Domain Interactions as Examined by Protein Semisynthesis

PDZ domains are ubiquitous small protein domains that are mediators of numerous protein–protein interactions, and play a pivotal role in protein trafficking, synaptic transmission, and the assembly of signaling‐transduction complexes. In recent years, PDZ domains have emerged as novel and exciting drug targets for diseases (in the brain in particular), so understanding the molecular details of PDZ domain interactions is of fundamental importance. PDZ domains bind to a protein partner at either a C‐terminal peptide or internal peptide motifs. Here, we examined the importance of a conserved Lys/Arg residue in the ligand‐binding site of the second PDZ domain of PSD‐95, by employing a semisynthetic approach. We generated six semisynthetic PDZ domains comprising different proteogenic and nonproteogenic amino acids representing subtle changes of the conserved Lys/Arg residue. These were tested with four peptide interaction partners, representing the two different binding modes. The results highlight the role of a positively charged amino acid in the β1–β2 loop of PDZ domains, and show subtle differences for canonical and noncanonical interaction partners, thus providing additional insight into the mechanism of PDZ/ligand interaction.     

Investigation of the Influence of Pseudoinverse Matrix Calculations on Multibody Dynamics Simulations by Means of the Udwadia-Kalaba Formulation

The formulation of the dynamic equations of motion proposed by Udwadia-Kalaba is discussed from the point of view of numerical efficiency. Since this formulation requires the computation of a pseudoinverse matrix, it has investigated the influence of the method of pseudoinverse computation on the dynamic simulation of an overconstrained linkage. Finally, it has been proposed that a new dynamic equation which explicitly computes accelerations also in the case of mathematical models with rank deficient Jacobian and mass matrices.     

The systematic use of geotechnical data for characterization of transportation routes

An integrated system approach is presented describing the acquisition, organization and development of route geotechnical data/information for use in planning, analysis and design of complex transportation facilities in geo-technically variable terrain. A unified landform-based approach to geotechnical route characterization is conceptually delineated and formalized. Geotechnical functions required to process data are identified, defined, and integrated into a system within the overall facility design process. Probabilistic techniques used within the characterization approach can objectively consider geotechnical variability and uncertainty including limitations in available geotechnical data/ information. Procedures presented here provide geotechnical tools for project planning, analysis and design of transportation routes.     

Mechanical properties of textured ceramics from muscovite–kaolinite alternate layers

An organized network of mullite anisotropic crystals embedded in a silico-aluminate matrix material is obtained at interfaces of sintered alternate layers of muscovite and kaolinite minerals. The nucleation and growth of mullite anisotropic crystals occur preferentially along the muscovite basal planes through topotactic reaction with the high temperature form of muscovite.Simultaneously to structural transformations, dehydroxylation of muscovite induces an exfoliation process, which is temperature and time dependent. The kinetics of this process was controlled using an appropriate thermal cycle and uniaxial load. During sintering, the control of mullite size mainly depends in temperature and the addition of a small quantity of low-temperature liquid phase also favors the growth of mullite. But liquid induces the weakening of the organization degree of the mullite network. Quantitative texture analysis (QTA) and SEM were used to characterize microstructural characteristics.Flexural strength, Young modulus and fracture toughness are closely related to size and organization degree of the mullite network. In general, mullite length favors the increase of strength and fracture toughness. But a high organization degree of the mullite network favors the occurrence of interconnected crystals and increases mechanical properties.     

Isoenzymatic forms of human cytidine deaminase

Cytidine deaminase (CDA) purified from human placenta revealed the presence of five isoenzymatic forms that differ only in their isoelectric point. Since human cytidine deaminase exists in two variants (CDA 1 and CDA 2) with a non-conservative amino acid substitution at codon 27, in this work we demonstrate that these two variants may combine together in vitro, giving five CDA isoforms as observed in vivo from human placenta. For this purpose, each of the two forms of CDA was purified close to homogeneity and dissociated into monomers in the presence of a small amount of sodium dodecyl sulfate as a dissociating agent. The monomers were mixed together and subjected to anion-exchange chromatography and to chromatofocusing analysis in order to visualize the formation of the five isoforms. Furthermore, for both CDA 1 and CDA 2 some substrates and inhibitors of CDA were assayed, with the aim of demonstrating different kinetic behavior between the two natural variants.     

Characterisation of single-mode fibres by near-field measurement

A new technique for the determination of the refractive-index profile of single-mode optical fibres from a simple near-field measurement is proposed. This permits one to deduce accurately all the important parameters of the fibre.