Application of the chemiluminescence systems to evaluate the role of Fcgamma and complement receptors in stimulating the oxidative burst in neutrophils

We have established a luminol- and a lucigenin-dependent CL methods to investigate the role of the receptors for Fc portion of IgG (FcgammaR) and/or complement receptors (CR) in mediating the oxidative burst in neutrophils from systemic lupus erythematosus (SLE) patients compared with healthy controls. In the luminol-CL system, all the reactive oxygen species (ROS) are responsible for light production, whereas in the lucigenin-CL system, only the first ROS generated, converts the lucigenin into an unstable intermediate molecule, which also emits light. First, neutrophils from healthy controls and SLE patients were stimulated with different IC opsonized or not with complement from normal human serum (NHS) or SLE serum, in presence of 10(-4) M luminol. This method was able to differentiate the role of the FcgammaR, CR and FcgammaR/CR co-operation in mediating the oxidative burst, as well as show that the oxidative burst mediated by these receptors was reduced in neutrophils from SLE patients. Second, neutrophils from healthy controls and SLE patients were stimulated with different IC, opsonized or not with NHS, in presence of 10(-3) M lucigenin. In this case, the lucigenin-CL system was also able to differentiate the role of FcgammaR and FcgammaR/CR co-operation, as well as show differences among healthy controls and two different groups of SLE patients according to their clinical manifestations. In conclusion, we have established two sensitive CL systems to study the role of FcgammaR and/or CR in stimulating the oxidative burst of neutrophils, which can be applied in monitoring the involvement of these receptors in the immunopathogenesis of SLE.     

On a class of singular biharmonic problems involving critical exponents

This paper deals with the following class of singular biharmonic problems

     

Direction of magnetization and domain wall mobility in (Dy,Y)Fe2

Magnetization measurements in the (Dy _x Y_1−x )Fe₂ intermetallic compounds show evidence of blocking of domain wall motion. This effect is a function of concentrationx. The direction of magnetization is also dependent on the Dy concentration. We have used the Mossbauer spectroscopy of⁵⁷Fe to verify the direction of magnetization in the series as a function ofx and temperature. The results show that this change in easy direction occurs at higher temperatures than those where the blocking is detected through DC magnetization measurements. supported by RHAE/SCT.     

Magnetic nanoscale aggregates of cobalt and nickel in MgO single crystals

The magnetic properties of Co and Ni nanosized aggregates formed after implantation of nickel and cobalt ions in magnesium oxide single crystals were investigated. The influence of the implantation energy and annealing treatments was characterized. The particle size distribution was determined from the combined analysis of the magnetic moment dependence on both magnetic field and temperature, and used to determine the magnetic anisotropy constant of the aggregates. The results for nickel aggregates indicate the presence of an antiferromagnetic layer after the annealing treatments.     

Structural and spectroscopic properties of the diazocarbene radical (CNN) and its ions CNN+ and CNN−: a high-level theoretical investigation

The diazocarbene radical, CNN, and the ions CNN⁺ and CNN^? were investigated at a high level of theory. Very accurate structural parameters for the states X ³Σ^? and A ³Π of CNN, and X ²Π of both CNN⁺ and CNN^? were obtained with the UCCSD(T) method using correlated-consistent basis functions with extrapolations to the complete basis set limit, with valence only and also with all electrons correlated. Harmonic and anharmonic frequencies were obtained for all species and the Renner parameter and average frequencies evaluated for the Π states. At the UCCSD(T)/CBS_T-5 level of theory, Δ_f H(0 K) = 138.89 kcal/mol and Δ_f H(298 K) = 139.65 kcal/mol were obtained for diazocarbene; for the ionization potential and the electron affinity of CNN, 10.969 eV (252.95 kcal/mol), and 1.743 eV (40.19 kcal/mol), respectively, are predicted. Geometry optimization was also carried out with the CASSCF/MRCI/CBS_T-5 approach for the states X ³Σ^?, A ³Π, and a ¹Δ of CNN, and with the CASSCF/MRSDCI/aug-cc-pVTZ approach for the states b ¹Σ⁺, c ¹Π, d ¹Σ^?, and B ³Σ^?, and excitation energies (T_e) evaluated. Vertical energies were calculated for 15 electronic states, thus improving on the accuracy of the five transitions already described, and allowing for a reliable overview of a manifold of other states, which is expected to guide future spectroscopic experiments. This study corroborates the experimental assignment for the vertical transition X ³Σ^? ← E ³Π.     

Analysis of Methods of Performance Evaluation of Direct-Detection Orthogonal Frequency Division Multiplexing Communication Systems

Abstract

The performance assessment of orthogonal frequency division multiplexing signals in direct-detection transmission systems by using the error vector magnitude and several bit error ratio approaches is analyzed and compared through numerical simulation. It is shown that excellent accuracy of the bit error ratio estimates is obtained by a semi-analytical Gaussian approach for all the orthogonal frequency division multiplexing system configurations analyzed and that the error vector magnitude only provides reliable estimates of the system performance when the system is dominantly impaired by noise. Additionally, a novel Q-factor approach for orthogonal frequency division multiplexing optical signals showing improved bit error ratio estimates is also presented.