On fractional integro-differential inclusions with state-dependent delay in Banach spaces

In this article we investigate the existence of solutions on a compact interval for the fractional integro-differential inclusions with state-dependent delay in Banach spaces when the delay is infinite. We consider the cases when the multivalued nonlinear term takes convex values as well as nonconvex values.     

Information theoretical study of chirality: enantiomers with one and two asymmetric centra

In this work, the Kullback-Leibler information deficiency is probed as a chirality measure. It is argued that the information deficiency, calculated using the shape functions of the R and S enantiomers, considering one as reference for the other, gives an information theory based expression useful for quantifying chirality. The measure is evaluated for five chiral halomethanes possessing one asymmetric carbon atom with hydrogen, fluorine, chlorine, bromine, and iodine as substituents. To demonstrate the general applicability, a study of two halogen-substituted ethanes possessing two asymmetric carbon atoms has been included as well. The basic expression of the sum of the local information deficiency over all atoms can be decomposed into separate summations over coinciding and noncoinciding atoms, or into a global and a mixing entropy term, or into a local entropy contribution for each atom individually based on the Hirshfeld partitioning. Avnir's continuous chirality measure (CCM) has been computed and confronted with the information deficiency. Finally, the relationship between chirality and optical rotation is used to study the proposed measure. The results illustrate Mezey's holographic electron density theorem with an intuitively appealing division of the strength of propagation of the atomic chirality from an asymmetric carbon atom throughout the molecule. The local information deficiency of the carbon atom is proposed as a measure of chirality; more precisely, the difference in information between the R and the S enantiomer turns out to be a quantitative measure of the chirality of the system. It may be evaluated as the arithmetic mean of the different alignments, or considering only the alignment resulting in the highest similarity value, or using the QSSA alignment.     

Cholesterylbutyrate solid lipid nanoparticles as a butyric acid prodrug

Cholesterylbutyrate (Chol-but) was chosen as a prodrug of butyric acid. Butyrate is not often used in vivo because its half-life is very short and therefore too large amounts of the drug would be necessary for its efficacy. In the last few years butyric acid's anti-inflammatory properties and its inhibitory activity towards histone deacetylases have been widely studied, mainly in vitro. Solid Lipid Nanoparticles (SLNs), whose lipid matrix is Chol-but, were prepared to evaluate the delivery system of Chol-but as a prodrug and to test its efficacy in vitro and in vivo. Chol-but SLNs were prepared using the microemulsion method; their average diameter is on the order of 100-150 nm and their shape is spherical. The antineoplastic effects of Chol-but SLNs were assessed in vitro on different cancer cell lines and in vivo on a rat intracerebral glioma model. The anti-inflammatory activity was evaluated on adhesion of polymorphonuclear cells to vascular endothelial cells. In the review we will present data on Chol-but SLNs in vitro and in vivo experiments, discussing the possible utilisation of nanoparticles for the delivery of prodrugs for neoplastic and chronic inflammatory diseases.     

Stereoselective synthesis of N-aryl proline amides by biotransformation-Ugi-Smiles sequence

An efficient combination of MAO-N-catalyzed desymmetrization of cyclic meso-amines with Ugi-Smiles multicomponent chemistry produced optically pure N-aryl proline amides. This method represents the first report of a fully asymmetric Ugi-Smiles process.     

Residue-specific pKa determination of lysine and arginine side chains by indirect 15N and 13C NMR spectroscopy: application to apo calmodulin

Electrostatic interactions in proteins can be probed experimentally through determination of residue-specific acidity constants. We describe here triple-resonance NMR techniques for direct determination of lysine and arginine side-chain protonation states in proteins. The experiments are based on detection of nonexchangeable protons over the full range of pH and temperature and therefore are well suited for pKa determination of individual amino acid side chains. The experiments follow the side-chain 15Nzeta (lysine) and 15Nepsilon or 13Czeta (arginine) chemical shift, which changes due to sizable changes in the heteronuclear electron distribution upon (de)protonation. Since heteronuclear chemical shifts are overwhelmed by the charge state of the amino acid side chain itself, these methods supersede 1H-based NMR in terms of accuracy, sensitivity, and selectivity. Moreover, the 15Nzeta and 15Nepsilon nuclei may be used to probe changes in the local electrostatic environment. Applications to three proteins are described: apo calmodulin, calbindin D9k, and FKBP12. For apo calmodulin, residue-specific pKa values of lysine side chains were determined to fall between 10.7 and 11.2 as a result of the high net negative charge on the protein surface. Ideal two-state titration behavior observed for all lysines indicates the absence of significant direct charge interactions between the basic residues. These results are compared with earlier studies based on chemical modification.     

A DFT study on the complexation of La3+ ion with malonamide and diglycolamide ligands

The main goal of this research is to investigate the structural and thermochemical aspects of complexation between La³⁺ with tetrapropyl malonamide (TPMA) and tetrapropyl diglycolamide (TPDGA) ligands via density functional theory (DFT) methods. In this respect, the structural parameters of [La-TPMA]³⁺ and [La-TPDGA]³⁺ complexes have been calculated and compared with the available X-ray crystallographic data. These comparisons revealed that both calculated structural values using B3LYP and M06 are in a reliable agreement with X-ray crystal structure with a near accuracy. In the next step, the more efficiency of diglycolamides in comparison with malonamides in the extraction of La³⁺ have been analyzed by calculating thermochemical properties of the complexation. It should be stated that this issue has been observed in many experimental elucidations. In the next step, the inclusion of solvent effects on thermodynamical properties of complexation has been evaluated via polarized continuum model (PCM) calculations. In this context, enthalpy and Gibbs free energy changes have been determined in the presence of three solvents, chloroform, toluene and n-hexane. Our obtained results demonstrate that using n-hexane as solvent is more favorable thermodynamically than chloroform and toluene that confirms the previously observed experiments. Finally, the bond orders of some selected key bonds in TPMA and TPDGA ligands and their corresponded La³⁺ complexes have been evaluated comparatively to analyze the electronic features of coordination in [La-TPMA]³⁺ and [La-TPDGA]³⁺ complexes.     

Mechanistic studies on the formation of glycosidase-substrate and glycosidase-inhibitor covalent intermediates

Glycoside hydrolases catalyze the breaking of the glycosidic bond. This type of bond fashioned between two monosaccharides is very stable, and the polymers created are involved in multiple cellular processes, being crucial to life. In this article, computational methods were used to study the first step of the mechanism of reaction of retaining glycoside hydrolases in atomic detail. The systems modeled included a simplified reaction center and a small substrate/inhibitor. Using DFT calculations we were able to corroborate and provide molecular-level detail to the dissociative mechanism proposed in the literature. The role of the hydrogen bridge between the nucleophile and the C(2)--OH group of the ring was also investigated. Therefore, we concluded that this bridge is responsible for lowering the activation barrier by 5.1 kcal mol(-1) with functional BB1K/6-311+G(2d,2p), and the absence of the bridge explains, at least in part, the inhibitory effect of fluoro-substituted glycosides in the -2 position. The hydrogen bridge could also be involved in favoring the ring distortion verified in the transition state, and the dissociative character of the reaction mechanism. Using the NBO method, point atomic charges were calculated. In the transition state, the positive charge generated in the sugar ring is distributed nearly equally between the anomeric carbon and the ring oxygen, through a partial double bond involving the two atoms.     

A Systematic Study of ZnO/CuO Core/Shell Nanostructures Pegylated by Microwave Assistant Reverse Micelles (RM) Method

In this work we synthesized ZnO/CuO nanostructures pegylated by simple and fast microwave method assistant reverse micelles, Reverse micelles protocol creates many advantages in stability, particle size control, morphology, density, loading level, distribution, uniformity, charge and purification. Based on the statistical results ZnO/CuO nanostructures placed in the hydrophilic substrate. The effect of microwave and concentration of surfactant on the surface area, pore diameter and pore volume of the final product was systematically studied using Taguchi technique. ZnO/CuO core/shell pegylated nanostructures, indicating a ZnO as core and CuO as shell and continuous micelles chains around this structures. Products were characterized by UV–Vis spectra, X-ray diffraction, scanning electron microscopy, Dynamic light scattering, Energy-dispersive X-ray spectroscopy, transmission electron microscopy and nitrogen adsorption (i.e. Brunauer–Emmett–Teller surface area analysis).     

Dual catalysis with an Ir(III)-Au(I) heterodimetallic complex: reduction of nitroarenes by transfer hydrogenation using primary alcohols

A triazolyl-di-ylidene ligand has been used for the preparation of a homodimetallic complex of gold, and a heterodimetallic compound of gold and iridium. Both complexes have been fully characterized and their molecular structures have been determined by means of X-ray diffraction. The catalytic properties of these two complexes have been evaluated in the reduction of nitroarenes by transfer hydrogenation using primary alcohols. The two complexes afford different reaction products; whereas the Au(I)-Au(I) catalyst yields a hydroxylamine, the Ir(III)-Au(I) complex facilitates the formation of an imine.     

Characterization of lead and lead leaching properties of lead glazed ceramics from the Solis Valley, Mexico, using inductively coupled plasma-mass spectrometry (ICP-MS) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFT)

Ingestion of relatively small amounts of lead is now recognized to cause significant neurological and cognitive effects in humans. Large quantities may be fatal, yet lead poisoning, especially of children, is still a major public health concern in many parts of the world. In rural Mexican communities lead oxide (PbO) is added to ceramic glaze as a fluxing agent, lowering starting firing temperatures to 500 °C. The purpose of this study is to characterize the lead chemical forms in ceramic glazes from the Solis Valley, Mexico, to investigate lead leaching properties of these ceramics, and to demonstrate the applicability of lead isotope signatures as a means of tracing lead source origins. Ceramics were collected from the rural village of Santa Maria de Canchesda, State of Mexico, Mexico. Dried liquid glazes, post-fired glaze material, and pure PbO were analyzed by diffuse reflectance infrared Fourier transform spectroscopy (DRIFT). Results from DRIFT analysis indicate that PbO (1429 cm⁻¹ band) is the active form of lead found in liquid glazes and ceramics. Some shifting of 1429 cm⁻¹ PbO peak to lower wavenumbers occurs in post-fired ceramics, and this may be due to the formation of lead bisilicate during firing. Ceramics samples were leached in 0.02 M citric acid solution for 1 min, and leached lead concentrations were measured using inductively coupled plasma-mass spectrometry (ICP-MS). Lead concentrations in these leachates varied from 0.4-80.4 μg ml⁻¹, while the control pottery from the US leached only 0.1 μg ml⁻¹ lead. Elemental distributions on glaze surfaces were identified by laser ablation (LA)-ICP-MS. Nitric acid extracts of soils, teeth, and ceramic glazes were analyzed for lead isotope ratios (²⁰⁷Pb/²⁰⁶Pb vs. ²⁰⁸Pb/²⁰⁶Pb) using ICP-MS. Similarities of tooth and ceramic lead isotope ratios indicate that ceramics may be a substantial source of body lead burden in the Solis Valley. This study demonstrates the applicability of lead isotope ratios for lead source identification, and it identifies potential health risks from ceramic use induced lead toxicity within the Solis Valley.