Preparation and characterization of MgB2 superconductor

The MgB₂ superconductor, synthesized using solid-state and liquid-phase sintering methods, have been characterized for various properties. The upper critical field, irreversibility line and critical current density have been determined using magnetization data. The current-voltage characteristics recorded under an applied magnetic field revealed the existence of vortex glass transition. The surface analysis using X-ray photoelectron spectroscopy shows that MgB₂ is sensitive to atmospheric degradation.     

Fixed point theorems in partially ordered Banach spaces with applications to nonlinear fractional evolution equations

In this paper, a notion of partially Hausdorff measure of noncompactness in partially ordered Banach spaces is introduced, and some Krasnoselskii-type fixed point theorems under certain mixed conditions are proved. Some applications of the obtained fixed point theorems are given to a class of fractional hybrid evolution equations for proving the existence of mild solutions under certain monotonicity conditions. At the end, an example of the fractional parabolic equation is given to illustrate the abstract results.     

Spectrophotometric determination of thorium in standard samples and monazite sands based on the floated complex of thorium with N-hydroxy-N,N'-diphenylbenzamidine and thorin

A selective and sensitive spectrophotometric method for the determination of Th(IV) has been based on the reaction with thorin and subsequent extraction of the red-orange coloured complex with N-hydroxy-N,N-diphenylbenzamidine (HDPBA) in benzene as floated complex at pH 2.2. The complex in ethanol exhibits a maximum absorbance at 495 nm, with a molar absorptivity of 6.0×10⁴ lmol^-1cm^-1, with a Sandells sensitivity of 3.9×10^-3 gcm^-2. The method follows Beers law up to 3.0 g Th(IV) ml^-1. None of the common cations and anions tested interfere. The detection limit of the method is 0.04 g Th(IV) ml^-1, the RSD (n=10) is 1.4%. The method has been successfully employed for the determination of thorium in various standard and monazite samples.     

Adaptive silver films for detection of antibody-antigen binding

Antibody-antigen binding events at a monolayer protein concentration have been demonstrated on nanostructured adaptive silver films (ASFs) using surface-enhanced Raman scattering (SERS) and luminescence-based assays. It is shown that proteins stabilize and restructure the ASF to increase the SERS signal while preserving antigen-binding activity. Evidence for antibody-antigen binding on the ASF substrates is the distinct SERS spectral changes of the surface-bound antibody or antigen without special tags. The activity of the surface-bound proteins and their practical application are validated by independent immunochemical assays. Results are presented to demonstrate that these surfaces can be extended to protein arrays with detection applications distinct from current SERS, fluorescence, or luminescence methods.     

Common fixed point theorems for four mappings through generalized altering distances in ordered metric spaces

Using the concepts introduced by Abbas et?al. (Appl Math Lett 24:1520?C1526, 2011), the purpose of this paper is to establish coincidence point and common fixed point results for four maps satisfying generalized weak contractions under generalized altering distance functions in ordered complete metric spaces.