Thermodynamic study of the interaction of Co(II)-Schiff base complexes with phosphines

The equilibrium constants and the thermodynamic parameters for the interaction of CoL^x (L¹ = 5-OMe-salabza, L² = salabza, L³ = 5-Br-salabza and L⁴ = 5-NO₂-salabza) as acceptors, with phosphines (PBu₃, PPh₂Me) as donors in dichloromethane were studied. This was performed by using UV-Vis spectrophotometry titration for 1:1 adduct formation of the selected complexes at various temperatures (T = 283–298 K). The trend of the adduct formation of the Co(II) complexes with a given phosphine donor decreases as CoL¹ > CoL² > CoL³ > CoL⁴. The stability of the resulting adducts with different Co(II)-schiff base complexes found to decrease in the order PBu₃ > PPh₂Me.     

Local Part of Two Neutron Separation Energies: Signature of Ground State Phase Transition

Physics of Particles and Nuclei Letters - In this paper, we have considered the evolution of the local part of two neutron separation energies in the Zr, Gd, Sm, Ba, Xe, Os and Pt isotopic chain....     

Analysis of multiple axisymmetric annular cracks in a piezoelectric medium

An axisymmetric annular electric dislocation is defined. The solution of axisymmetric electric and Volterra climb and glide dislocations in an infinite transversely isotropic piezoelectric domain is obtained by means of Hankel transforms. The distributed dislocation technique is used to construct integral equations for a system of co-axial annular cracks with so-called permeable and impermeable electric boundary conditions on the crack faces where the domain is under axisymmetric electromechanical loading. These equations are solved numerically to obtain dislocation densities on the crack surfaces. The dislocation densities are employed to determine field intensity factors for a system of interacting annular and/or penny-shaped cracks.     

A full Nesterov–Todd step infeasible-interior-point algorithm for Cartesian P*(κ) horizontal linear complementarity problems over symmetric cones

Euclidean Jordan algebra is a commonly used tool in designing interior-point algorithms for symmetric cone programs. In this paper, we present a full Nesterov–Todd (NT) step infeasible interior-point algorithm for horizontal linear complementarity problems over Cartesian product of symmetric cones. Since the algorithm uses only full-NT feasibility and centring steps, it has the advantage that no line searches are needed. The complexity result obtained here for symmetric cones using NT directions coincides with the best bound obtained for horizontal linear complementarity problems.     

Some new Schiff base ligands giving a NNOS coordination sphere and their nickel(II) complexes: Synthesis,characterization and complex formation

Some new tetradentate ligands with a NNOS coordination sphere were prepared and their corresponding nickel(II) complexes were synthesized and characterized by elemental analysis, IR, ¹H NMR, UV–Vis and mass spectrophotometry. The thermodynamic formation constants of the complexes were measured spectrophotometrically, at a constant ionic strength of 0.1 M (NaClO₄) at 25 °C in DMF solvent. The trend of the complex formation for nickel is as follows:     

Magnetic molecularly imprinted polymer nanoparticles for the solid-phase extraction of paracetamol from plasma samples,followed its determination by HPLC

We are presenting magnetic molecularly imprinted polymer nanoparticles (m-MIPs) for solid-phase extraction and sample clean-up of paracetamol. The m-MIPs were prepared from magnetite (Fe₃O₄) as the magnetic component, paracetamol as the template, methacrylic acid as a functional monomer, and 2-(methacrylamido) ethyl methacrylate as a cross-linker. The m-MIPs were then characterized by transmission electron microscopy, FT-IR spectroscopy, X-ray diffraction and vibrating sample magnetometry. The m-MIPs were applied to the extraction of paracetamol from human blood plasma samples. Following its elution from the column loaded with the m-MIPs with an acetonitrile-buffer (9:1) mixture, it was submitted to HPLC analysis. Paracetamol can be quantified by this method in the 1 μg L^?1 to 300 μg L^?1 concentration range. The limit of detection and limit of quantification in plasma samples are 0.17 and 0.4 μg L^?1. The preconcentration factor of the m-MIPs is 40. The HPLC method shows good precision (4.5 % at 50 μg L^?1 levels) and recoveries (between 83 and 91 %) from spiked plasma samples. Figure

We are presenting magnetic molecularly imprinted polymer nanoparticles (m-MIPs) for solid-phase extraction and sample clean-up of paracetamol. The m-MIPs were applied to the extraction of paracetamol from human blood plasma samples     

Magnetic molecularly imprinted polymer nanoparticles for the solid-phase extraction of paracetamol from plasma samples,followed its determination by HPLC

We are presenting magnetic molecularly imprinted polymer nanoparticles (m-MIPs) for solid-phase extraction and sample clean-up of paracetamol. The m-MIPs were prepared from magnetite (Fe₃O₄) as the magnetic component, paracetamol as the template, methacrylic acid as a functional monomer, and 2-(methacrylamido) ethyl methacrylate as a cross-linker. The m-MIPs were then characterized by transmission electron microscopy, FT-IR spectroscopy, X-ray diffraction and vibrating sample magnetometry. The m-MIPs were applied to the extraction of paracetamol from human blood plasma samples. Following its elution from the column loaded with the m-MIPs with an acetonitrile-buffer (9:1) mixture, it was submitted to HPLC analysis. Paracetamol can be quantified by this method in the 1 μg L⁻¹ to 300 μg L⁻¹ concentration range. The limit of detection and limit of quantification in plasma samples are 0.17 and 0.4 μg L⁻¹. The preconcentration factor of the m-MIPs is 40. The HPLC method shows good precision (4.5 % at 50 μg L⁻¹ levels) and recoveries (between 83 and 91 %) from spiked plasma samples.

We are presenting magnetic molecularly imprinted polymer nanoparticles (m-MIPs) for solid-phase extraction and sample clean-up of paracetamol. The m-MIPs were applied to the extraction of paracetamol from human blood plasma samples

     

Chip-Firing and Riemann-Roch Theory for Directed Graphs

Baker and Norine developed a graph theoretic analogue of the classical Riemann-Roch theorem. Amini and Manjunath extended their criteria to all full-dimensional lattices orthogonal to the all ones vector. We show that Amini and Manjunath?s criteria holds for all full-dimensional lattices orthogonal to some positive vector and study some combinatorial examples of such lattices. Two distinct generalizations of the chip-firing game of Baker and Norine to directed graphs are provided. We describe how the “row” chip-firing game is related to the sandpile model and the “column” chip-firing game is related to directed G-parking functions. We finish with a discussion of arithmetical graphs, introduced by Lorenzini, viewing them as a class of vertex weighted graphs whose Laplacian is orthogonal to a positive vector and describe how they may be viewed as a special class of unweighted strongly connected directed graphs.     

Study of corrosion protection of mild steel by eco-friendly silane sol–gel coating

The effects of dipping duration in the silane solution and the sol pH on the protective performance of an eco-friendly silane sol–gel coating consisting a mixture of tetraethoxysilane, methyltriethoxysilane and glycidyloxypropyltrimethoxysilane applied on mild steel substrate were studied in this paper using electrochemical techniques and surface analysis. In consistency with the data obtained from electrochemical impedance spectroscopy and polarization curves, electrochemical current noise fluctuation analysis, appearance of the power spectral density plots and noise resistance indicated the most efficient sol pH and immersion time in the silane solution. In this regard, field emission type scanning electron microscopy images and water contact angle values revealed impact of the sol pH on the film structure. The enhancement in protective performance of the hybrid coating resulting from optimum immersion in the silane solution with appropriate pH was connected to the film homogeneity and higher cross linking and thickness as well. Moreover, a good trend correlation was observed between the noise resistance and low-frequency impedance modulus data.