Study of Blood Selenium Level in Thyroid Pathologies by Instrumental Neutron Activation Analysis

Abstract

Selenium deficiency constitutes a risk factor for several pathologies (congestive cardiomyopathie, cancer, etc.). It was shown, recently, that selenium is implied in thyroid metabolism. It constitutes the catalytic site of the enzymes intervening in thyroid hormone synthesis. In the present work, we determined concentrations of selenium in total blood of 39 patients suffering from thyroid pathologies (hyperthyroidism [HEP], hypothyrodism [HOP], simple goiter [SG]), and 29 normal controls using instrumental neutron activation analysis (INAA). The blood selenium concentrations of patients suffering from hyperthyroidism was 142.56±20.25 µg/L of total blood, which is significantly lower than that of normal controls (206.72±17.98 µg/L. p≤0.05). No significant differences were observed in the concentrations of Se in hypothyroidism (184.26±20.77 µg/L) and simple goiter groups (160.47±25.76 µg/L).     

Micromechanical modeling of the rolling of a A1050P aluminum sheet

A micromechanical ductile fracture model, extended to take account thermal heating due to mechanical dissipation within the material, is used to study a 3D-asymmetric rolling operation. The void coalescence mechanism by intervoid material ligament necking is also considered by using an extension of the Thomason’s criteria. This formulation is implemented into ABAQUS/Explicit finite element package and applied to simulate the effects of some rolling parameters on the evolution of the voids volume fraction and voids shape of a A1050P aluminum. The confrontation with available experimental results shows the capability of this constitutive law to predict the rolling force variation for different reductions. The results show, on one hand, that optimum parameters could be found in order to reduce the rolling force and, on the other hand, that rolling parameters exert an influence on the final microstructure of the rolled metal.     

A cyclic binary morphism avoiding Abelian fourth powers

We exhibit a cyclic binary morphism avoiding Abelian fourth powers.     

Encapsulation and Oxidative Stability of PUFA-Rich Oil Microencapsulated by Spray Drying Using Pea Protein and Pectin

This study aimed at evaluating the potential of pectin combination with pea protein isolate (PPI) in the microencapsulation of polyunsaturated fatty acids (PUFA)-rich oil by spray drying, in order to maximize encapsulation efficiency and minimize lipid oxidation. The feed emulsions used for particle production consisted of PUFA-rich oil droplets coated by either PPI (primary emulsion) or PPI–pectin (secondary emulsion). Dry emulsions characteristics and oxidative stability of microencapsulated oil as a function of relative humidity (RH; from 11 % to 75 %) were determined. Scanning electron microscopy (SEM) images revealed considerable structural changes. Oil droplets retained their shape upon drying and reconstitution. However, a shift in oil droplet size upon reconstitution indicated that oil droplet coalescence occurred within the process. Oxidation of microencapsulated oil in secondary emulsion was delayed from that of primary emulsion but followed the same pattern with regards to humidity. A high rate of oxidation was found for intermediate RH conditions (33 % and 57 % RH). The lowest rate of oxidation as followed by hydroperoxide and thiobarbituric acid reactive substances values was found at 75 % RH, a condition that is likely to diverge significantly from the monolayer moisture value. The oxidative stability of encapsulated oil was influenced by both physical state of the emulsions and the different constituents at the oil-in-water interface with PPI–pectin secondary emulsion giving the best protection of the oil.     

Structuration mechanism of β-lactoglobulin – acacia gum assemblies in presence of quercetin

The interactions of β-lactoglobulin (BLG) with total Acacia gum (TAG) in presence of quercetin have been investigated in aqueous solutions at pH 4.2 and 25 °C. Isothermal titration calorimetry (ITC) has been used to determine the type and magnitude of the energies involved in the complexation process. Dynamic light scattering (DLS), electrophoretic mobility (μ_E), turbidity measurements (τ), optical microscopy and Fourier transform infrared spectroscopy in total attenuated reflection mode (ATR-FTIR) were used as complementary methods to better understand the sum of complicated phenomena at the origin of thermodynamic behaviour.     

On computing the stabilizing solution of a class of discrete‐time periodic Riccati equations

This paper addresses the problem of solving a class of periodic discrete‐time Riccati equation with an indefinite sign of its quadratic term. Such an equation is closely related to the so‐called full‐information H _∞ control of discrete‐time periodic systems. A globally convergent iterative algorithm with a local quadratic convergence rate is proposed for this purpose. An application to the problem of H _∞ filtering of discrete‐time periodic systems is also developed and illustrated via a numerical example. Copyright © 2013 John Wiley & Sons, Ltd.     

Co-design of safe networked control systems

Modeling, analysis and control of networked control systems (NCS) have recently emerged as topics of significant interest to the control community. The defining feature of any NCS is that information is exchanged using digital band-limited serial communication channel among systems components and usually shared by other feedback control loops. Conventional control theory with many ideal assumptions, such as synchronized control and non-delayed sensing and actuation must be revisited so that the limitations on communication capabilities within the control design framework can be integrated. Recent achievements showed that it is possible to solve communication problems and control problems simultaneously, thus contributing to a more efficient NCS design. This paper aims at giving an overview of Fault Diagnosis methods dealing with enhancement of robustness against network induced effects and introducing co-design approaches making it possible to solve communication problems and control problems simultaneously, thus contributing to a more efficient design.     

Static and Dynamic Tearing of Thin Steel Sheets

This paper presents the energy analysis of static mode III fracture of thin steel sheets. For dynamic tearing studies we used the Charpy test apparatus. Static tearing tests performed on three types of steel sheets indicate that the linear relationship of Mai and Cotterell is valid for specimens with a leg width W up to 30 mm. In the given range, the specific work of fracture _e is determined according to the Mai–Cotterell model. The _e kinetics is studied as a function of the sheet thickness B, radius of curvature , and loading rate V. The modified model includes a linear dependence of versus W. Moreover, we show that variation of the loading rate V from 1 to 300 mm/min has no effect on the specific work of fracture _e. A slight decrease in the dynamic fracture toughness J_0,d has been found.     

Characterization of high-milk-protein powders upon rehydration under various salt concentrations

Rehydration of native micellar casein and native whey isolate protein powders was followed in different ionic environments. Solutions of NaCl and CaCl₂ in the concentration range of 0 to 12% (wt%) were used as rehydration media. The rehydration profiles obtained were interpreted in terms of wetting, swelling, and dispersion stages by using a turbidity method. Two behaviors were observed depending on the salt concentration. For native micellar casein powder, a significant change was observed between 3 and 6% NaCl and between 0.75 and 1.5% CaCl₂. The first behavior (low salt concentration) presents a typical rehydration profile: quick wetting, swelling, and long dispersion stage. The dispersion stage of the second behavior (high salt concentration) was significantly shortened, indicating a strong modification of the protein backbone. The rehydration of whey protein powder was less influenced by salts. At low salt concentrations, a typical profile for whey powders was observed: wetting with lump formation and no swelling followed by a quick dispersion. At high CaCl₂ concentrations, no turbidity stabilization was observed, indicating a possible protein unfolding and denaturation. Additionally, the changes in secondary structures of the 2 proteins upon salt increase were followed by Fourier transform infrared spectroscopy and confirmed the different profiles observed.