Pyridine solvated dioxouranium complex with salen ligand: Synthesis,characterization and luminescence properties

A new derivative of dioxouranium(VI) salen complex, [UO2(L)(pyridine)], where [L = N,N′-Bis(2-hydroxybenzylidene)-2,2-dimethyl-1,3-propanediamine] is synthesized and characterized by elemental analysis (C, H, N), FT-IR, ESI-MS spectrometry, UV/Vis, fluorescence, ¹H and ¹³C NMR spectroscopy and thermal gravimetric (TG) study. Furthermore, the single crystal X-ray diffraction measurements of the complex were carried out at 100 and 273 K. The crystal structure measurements revealed that the complex has distorted pentagonal bipyramidal geometry with uranium atom located at the centre and bonded to two phenoxy oxygen and two azomethine nitrogen in tetradenate fashion and one nitrogen from pyridine making it seven coordinated. In addition, the photoluminescence property of the complex was also recorded.     

Local mean field models of uniform to nonuniform density fluid-crystal transitions

We investigate the existence of nontranslation invariant (periodic) density profiles, for systems interacting via translation invariant long-range potentials, as minimizers of local mean field free energy functionals. The existence of a second-order transition from a uniform to a nonuniform density at a specified temperature is proven for a class of model systems.     

Polarographic reduction of some guanylpyrazoline nitrates and the effect of double layer structure on E1/2 values

Polarographic reduction of 4-arylhydrazono-1-guanylnitrate-3-methyl-2-pyrazoline-5-ones takes place in a single 4-electron transfer, giving a diffusion controlled irreversible wave in B.R. buffers of pH range 2.0–10.0. The reduction in these compounds takes place at the ?NH?N=C-bond. Effect of various cations, anions and solvent percentage on the reduction has been discussed. The effect of substituents and its correlation with the Hammett substituent constant (δ) have also been studied.     

Diode or tunnel-diode characteristics? Resolving the catalytic consequences of proton coupled electron transfer in a multi-centered oxidoreductase

Protein film voltammetry has been employed to define multiple catalytic consequences of proton coupled electron transfer (PCET) in a cytochrome c nitrite reductase. Current-potential profiles reflecting the steady-state rate of nitrite-limited reduction have been defined from pH 4 to 8. Lowering the electrode potential at pH 8 causes the catalytic current to increase and then decrease before it takes a value independent of any further lowering of electrode potential. By comparison, at pH 4, catalysis is initiated at more positive electrode potentials in an approximately sigmoidal fashion with no attenuation of the catalytic rate evident at more negative electrode potentials. The results show that activity is turned on by the coupled transfer of two electrons and one proton to the enzyme. The decreased rate of catalysis at lower electrode potentials under more alkaline conditions shows that this rate attenuation occurs only when reduction is not coupled to compensating protonation(s) of the enzyme. Sites within the enzyme whose reduction and/or protonation may contribute to the definition of these activities are discussed.     

Reaction of Cα,O-dilithiooximes with functionalized carbonyl compounds. Part 2 . Reaction with α-chloroketones and α,β-unsaturated aldehydes and ketones

The reaction of Cα,O-Dilithiooximes 2 and α-chloroketones afforded 5-(hydroxymethyl)-Δ²-soxazolines 4 . α,β-Unsaturated aldehydes and ketones reacted with 2 to give the corresponding acyclic 1,2-addition products 5 . The latter were cyclized with phosphorus pentoxide to 5-vinyl-Δ²-isoxazolines 6 .     

Affinity adsorption of recombinant human interferon-α on a porous dye-affinity adsorbent

Interferons are potent biologically active proteins synthesized and secreted by somatic cells of all mammalian species. Dye-affinity adsorption is increasingly used for protein separation. Hollow fibers have several advantages as adsorbents in comparison to conventional bead supports because they are not compressible and they eliminate internal diffusion limitations. The aim of this study was to explore in detail the performance of polyamide hollow fibers to which Cibacron Blue F3GA was attached for adsorption of recombinant interferon-α (rHuIFN-α). The hollow fiber was characterized by scanning electron microscopy. These dye-carrying hollow fibers (35.8 μmol/g) were used in the rHuIFN-α adsorption-elution studies. The effects of initial concentration of rHuIFN-α, medium pH, ionic strength and temperature on the adsorption efficiency of dye-attached hollow fibers were studied in a batch system. The non-specific adsorption of rHuIFN-α on the hollow fibers was 1.2 mg/g. Cibacron Blue F3GA attachment significantly increased the rHuIFN-α adsorption up to 99.8 mg/g. Significant amount of the adsorbed rHuIFN-α (up to 94.8%) was eluted in 1 h in the elution medium containing 1.0 M NaCl. In order to determine the effects of adsorption conditions on possible conformational changes of rHuIFN-α structure, fluorescence spectrophotometry was employed. We resulted that dye-affinity hollow fibers can be applied for rHuIFN-α adsorption without causing any significant conformational changes. Repeated adsorption/elution processes showed that these dye-attached hollow fibers are suitable for rHuIFN-α adsorption.     

Ternary and tetrahedral symmetry in hybrid fluorides, fluoride carbonates and carbonates

Tren amine cations and carbonate anions adopt a ternary symmetry while tetra amine cations are tetrahedral. The symmetry of these constitutive ions influences strongly the nature of the solids which crystallise from solutions. Large fluorinated aluminate polyanions with tetrahedral symmetry appear in the presence of tren amine, while infinite chains of AlF₆ octahedra are observed with tetra amine and that noncentrosymmetric structures are frequently encountered in rare earth fluoride carbonates.     

Cyphostemmins A-B, two new antifungal oligostilbenes from Cyphostemma crotalarioides (Vitaceae)

Two new antifungal resveratrol dimers, cyphostemmins A-B (1–2), have isolated from the roots of Cyphostemma crotalarioides planch (Vitaceae) together with resveratrol 3 and previously known reseveratrol dimers (4–7). Structures of these new compounds have been established on the basis of their MS and ¹H and ¹³C NMR spectroscopic data.     

A new approach for the derivation of bounds for the Jensen difference

There are many useful applications of Jensen's inequality in several fields of science, and due to this reason, a lot of results are devoted to this inequality in the literature. The main theme of this article is to present a new method of finding estimates of the Jensen difference for differentiable functions. By applying definition of convex function, and integral Jensen's inequality for concave function in the identity pertaining the Jensen difference, we derive bounds for the Jensen difference. We present integral version of the bounds in Riemann sense as well. The sharpness of the proposed bounds through examples are discussed, and we conclude that the proposed bounds are better than some existing bounds even with weaker conditions. Also, we present some new variants of the Hermite–Hadamard and Hölder inequalities and some new inequalities for geometric, quasi-arithmetic, and power means. Finally, we give some applications in information theory.