Dihydropyridazine-appended dibenzosuberenones as a new class of fluorophores: Application to fluoride sensing

Highly fluorescent, novel dihydropyridazine-appended dibenzosuberenone type dye molecules were obtained in a single step from simple compounds using Diels-Alder chemistry. This new fluorophore structure can be used for the construction of fluorescent chemosensors, as exemplified by selective and sensitive fluoride ion sensing. The –N–H protons in these structures are acidic enough to allow for fluoride-induced deprotonation, leading to a significant color change as well as a concomitant fluorescence quenching. These fluorophores possess large Stokes shifts, high quantum yields, and long fluorescence lifetimes; therefore, this study potentially paves the way for the construction of novel dye molecules for use in fluorescent dye applications.     

Synthesis of Mesoporous Lithium Titanate Thin Films and Monoliths as an Anode Material for High‐Rate Lithium‐Ion Batteries

Mesoporous Li₄Ti₅O₁₂ (LTO) thin film is an important anode material for lithium‐ion batteries (LIBs). Mesoporous films could be prepared by self‐assembly processes. A molten‐salt‐assisted self‐assembly (MASA) process is used to prepare mesoporous thin films of LTOs. Clear solutions of CTAB, P123, LiNO₃, HNO₃, and Ti(OC₄H₉)₄ in ethanol form gel‐like meso‐ordered films upon either spin or spray coating. In the assembly process, the CTAB/P123 molar ratio of 14 is required to accommodate enough salt species in the mesophase, in which the Li^I/P123 ratio can be varied between molar ratios of 28 and 72. Calcination of the meso‐ordered films produces transparent mesoporous spinel LTO films that are abbreviated as Cxx‐yyy‐zzz or CAxx‐yyy‐zzz (C=calcined, CA=calcined–annealed, xx=Li^I/P123 molar ratio, and yyy=calcination and zzz=annealing temperatures in Celsius) herein. All samples were characterized by using XRD, TEM, N₂‐sorption, and Raman techniques and it was found that, at all compositions, the LTO spinel phase formed with or without an anatase phase as an impurity. Electrochemical characterization of the films shows excellent performance at different current rates. The CA40‐350‐450 sample performs best among all samples tested, yielding an average discharge capacity of (176±1) mA h g^?1 at C/2 and (139±4) mA h g^?1 at 50 C and keeping 92 % of its initial discharge capacity upon 50 cycles at C/2.     

Cyclodextrin inclusion of four phenylurea herbicides: determination of complex stoichiometries and stability constants using solution 1H NMR spectroscopy

An inclusion complex formation between α- and β-cyclodextrin and four phenylurea analogues, namely metobromuron, monolinuron, monuron and fenuron, is reported. Complex formation was established using solution ¹H NMR spectroscopy. Complex stoichiometries were determined by the method of continuous variation using the chemically induced shifts of both the host and guest protons. An analysis of the spectroscopic data revealed the stoichiometry as 1:1 in all cases while a further analysis of the same data yielded values for the association constant K ranging from 208 to 2749 M^? 1. From the observed chemical shifts it was deduced that in all cases, only the guest aromatic ring enters the host cavities, the substituted urea moiety protruding from the secondary rim in the case of α-cyclodextrin, but from the primary rim in the case of β-cyclodextrin.     

Synthesis and Characterization of Magnesium Pyroborate by Solution Combustion and Conventional Ceramic Methods: A Comparative Study

Solution Combustion Synthesis (SCS) and ConventionalCeramic Process (CCP) were applied for the preparation of magnesium pyroborate (Mg₂B₂O₅) from Mg(NO₃)₂ · 6H₂O and H₃BO₃. Structural and morphological properties of the products were comparatively examined by XRD and FT‐IR spectroscopic measurements as well as SEM and BET techniques. The effects of synthesis conditions on the properties of products were investigated throughly by optimizing the B/Mg molar ratio and reaction duration in CCP and by optimizing the fuel (carbohydrazide) quantity in SCS. Pure Mg₂B₂O₅ (triclinicsuanite) was obtained by thermal treatment in CCP employing a B/Mg molar ratio of 3:1. It was found that the fuel must be in close proximity to the stoichiometric requirements in order to obtain the desired product in highly crystalline form from SCS. The Mg₂B₂O₅ samples obtained by both methods exhibited similar structural properties but different morphologies.     

The Generalized <Emphasis Type="Italic">PT</Emphasis>-Symmetric Sinh-Gordon Potential Solvable within Quantum Hamilton–Jacobi Formalism

The generalized Sinh-Gordon potential is solved within quantum Hamiltonian Jacobi approach in the framework of PT symmetry. The quasi exact solutions of energy eigenvalues and eigenfunctions of the generalized Sinh-Gordon potential are found for n=0,1 states.     

Čebyšev-Grüss-type inequalities revisited

We generalize and improve several inequalities of the ?eby?ev-Grüss-type using least concave majorants of the moduli of continuity of the functions involved. Our focus is on normalized positive linear functionals. We discuss a problem posed by the two Gavreas and also give the solution of a stronger one. In a section about the non-multiplicativity of positive linear operators it is demonstrated that the previous use of second moments is not quite the right choice. This is documented in the case of the classical Hermite-Fejér and de La Vallée Poussin convolution operators.     

Eigenvalue problems in anisotropic Orlicz–Sobolev spaces

We establish sufficient conditions for the existence of solutions to a class of nonlinear eigenvalue problems involving nonhomogeneous differential operators in Orlicz–Sobolev spaces. To cite this article: M. Mih?ilescu et al., C. R. Acad. Sci. Paris, Ser. I 347 (2009).     

Oriented immobilized anti‐hIgG via Fc fragment‐imprinted PHEMA cryogel for IgG purification

Antibodies are used in many applications, especially as diagnostic and therapeutic agents. Among the various techniques used for the purification of antibodies, immunoaffinity chromatography is by far the most common. For this purpose, oriented immobilization of antibodies is an important step for the efficiency of purification step. In this study, F_c fragment‐imprinted poly(hydroxyethyl methacrylate) cryogel (MIP) was prepared for the oriented immobilization of anti‐hIgG for IgG purification from human plasma. Non‐imprinted poly(hydroxyethyl methacrylate) cryogel (NIP) was also prepared for random immobilization of anti‐hIgG to compare the adsorption capacities of oriented (MIP/anti‐hIgG) and random (NIP/anti‐hIgG) cryogel columns. The amount of immobilized anti‐hIgG was 19.8 mg/g for the NIP column and 23.7 mg/g for the MIP column. Although the amount of immobilized anti‐hIgG was almost the same for the NIP and MIP columns, IgG adsorption capacity was found to be three times higher than the NIP/anti‐hIgG column (29.7 mg/g) for the MIP/anti‐hIgG column (86.9 mg/g). Higher IgG adsorption capacity was observed from human plasma (up to 106.4 mg/g) with the MIP/anti‐hIgG cryogel column. Adsorbed IgG was eluted using 1.0 m NaCl with a purity of 96.7%. The results obtained here are very encouraging and showed the usability of MIP/anti‐hIgG cryogel prepared via imprinting of Fc fragments as an alternative to conventional immunoaffinity techniques for IgG purification. Copyright © 2012 John Wiley & Sons, Ltd.