Identification of transgenic foods using NIR spectroscopy: A review

The utilization of chemometric methods in the quantitative and qualitative analysis of feeds, foods, medicine and so on has been accompanied with the great evolution in the progress and in the near infrared spectroscopy (NIRS). Hence, recently the application of NIR spectroscopy has extended on the context of genetics and transgenic products. The aim of this review was to investigate the application of NIR spectroscopy to identificate transgenic products and to compare it with the traditional methods. The results of copious researches showed that the application of NIRS technology was successful to distinguish transgenic foods and it has advantages such as fast, avoiding time-consuming, non-destructive and low cost in relation to the antecedent methods such as PCR and ELISA.     

Electrical and structural properties of Ce0.9CoFe3Sb12 thermoelectric thin films

In this work, we show experimental results for growth conditions of thermoelectric Ce_0.9CoFe₃Sb₁₂ thin films. An rf-magnetron sputtering system has been used to grow the films on single crystal substrates of sapphire (Al₂O₃), silicon (Si), and magnesium oxide (MgO) at different substrate temperatures between 250 and 450 °C. The films were thermoelectrically characterized with resistivity and thermopower measurements as functions of temperature. The results show linear behavior of resistivity with temperature, and thermopower growth with the temperature increase. Such behavior is typical for metallic materials. The structure and surface morphology of the samples were analyzed by X-ray diffraction pattern and atomic force microscopy (AFM), respectively.     

Euclidean submanifolds with Jacobi mean curvature vector field

We study submanifolds in the Euclidean space whose mean curvature vector field is a Jacobi field. First, we characterize them and produce non-trivial (non-minimal) examples and then, we look for additional conditions which imply minimality.Research partially supported by a DGICYT grant No PB94-0705-C02-01 and by a grant of Gobierno Vasco PI95/95     

Cyclic voltammetry study of the peptide Lys-Cys-Thr-Cys-Cys-Ala [56-61] MT i in the presence of cadmium

The electrochemical study of the peptidic fragment Lys-Cys-Thr-Cys-Cys-Ala [56–61] MT I (FT) alone and in the presence of cadmium was performed, by cyclic voltammetry using a hanging mercury drop electrode, in order to enable comparisons between the behavior of Cd, Zn metallothioneins and that of this less complex molecule, intrinsic to the metallothionein structure. The influence of the equilibration time, of the scan rate, and of the solution pH was investigated. The influence of the addition of cadmium with different Cd–FT ratios was also studied. Samples containing both Cd and FT give complex voltammograms showing different peaks. Several electrochemical systems were distinguished: the mercury electrode itself is involved in the charge transfer step in the presence of thiol groups coming from the FT structure; another system can be attributed to the oxido-reduction of cadmium either as free ion or complexed by the peptide. The adsorption phenomena play an important role in the electrochemical process. Both dissolved and adsorbed species are electroactive.     

Weighted Weak-type Estimates for Multilinear Commutators of Fractional Integrals on Spaces of Homogeneous Type

We obtain weighted distributional inequalities for multilinear commutators of the fractional integral on spaces of homogeneous type, The techniques developed in this work involve the behavior of some fractional maximal functions. In relation to these operators, as a main tool, we prove a weighted weak type boundedness result, which is interesting in itself.     

A Self-Averaging “Order Parameter” for the Sherrington-Kirkpatrick Spin Glass Model

Following an idea of van Enter and Griffiths, we define a self-averaging parameter for the Sherrington-Kirkpatrick (SK) spin glass which is a self-averaging version of the order parameter introduced by Aizenman, Lebowitz and Ruelle. It is strictly positive at low temperature and zero at sufficiently high temperature. The proof is based on the recent construction of the thermodynamic limit of the free energy by Guerra and Toninelli. We also discuss how our definition compares with various existing definitions of order-parameter like quantities.     

General Results on the Convergence of Multipoint Hermite-Pade Approximants of Nikishin Systems

We consider simultaneous approximation of Nikishin systems of functions by means of rational vector functions which are constructed interpolating along a prescribed table of points. We give general conditions for the uniform convergence of such approximants with a geometric rate under very weak assumptions.     

Kinetics of styrene emulsion polymerization above the critical micelle concentration: Effect of the initial monomer concentration on the molecular weight

The emulsion polymerization of styrene above the critical micelle concentration has been experimentally studied from a low final polymer content up to a high polymer content (～50%). A maximum in the molecular weight (M) evolution has been observed in all cases. The presence or absence of such a maximum depends on the relative values of the rate of free‐radical entry (ρ) and the rate of chain transfer to the monomer (K_trC_Mp, where K_tr is the chain transfer to monomer rate coefficient and C_Mp is the monomer concentration in particles). If ρ ? K_trC_Mp, M is constant and equal to K_p/K_tr (where K_p is the propagation rate coefficient), except at very low particles sizes typical of the early stages of the reaction, in which the chain length is limited by the particle size. On the other hand, if ρ ? K_trC_Mp, M is determined by both C_Mp and ρ. It is proposed that ρ is determined by the sum of the entry of the oligomeric radicals formed in the aqueous phase and those contained in particles that undergo limited coagulation. This coagulative entry can become very significant; therefore, reactor hydrodynamics can play a major role in the kinetic behavior observed. Disagreement between Clay and Gilbert's model and molecular weight distribution data can be ascribed, to a lesser or greater extent, to the degree of correctness of the quasi‐steady‐state and instantaneous‐termination approaches. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1963–1972, 2005     

Variational formulation of Chern–Simons theory for arbitrary Lie groups

We show that the Chern–Simons theory for a principal G-bundle P over a three-dimensional manifold, with G an arbitrary Lie group, can be formulated as a variational problem defined by local data on the bundle of connections C(P) of P. By means of the theory of variational problems defined by local data we prove that the Euler–Lagrange operator and the differential of the Poincaré–Cartan form can be intrinsically expressed in terms of the symplectic form and the curvature morphism of C(P). These facts and the theory of the global inverse problem of the Calculus of Variations allow us to prove that there is indeed a global Lagrangian density for these theories. We also prove that every infinitesimal automorphism of P produces in a natural way an infinitesimal symmetry of the variational problem defined by the Chern–Simons theory. We therefore conclude that the algebra of infinitesimal symmetries of these theories is infinite dimensional.