Syntheses, crystal structures, and quadratic nonlinear optical properties in four “push-pull” diorganotin derivatives

Four “push-pull” diorganotin compounds obtained by reaction of methoxysalicylaldehyde or 4-diethylaminosalicylaldehyde, 2-amino-5-nitrophenol and dibutyltin or diphenyltin oxide are reported. The molecular structures for the diphenyl derivatives, in the solid state, show a tin in a distorted trigonal bipyramid geometry with the oxygen atoms in axial positions and the organic moieties and iminic nitrogen in equatorial ones. For the dibutyl derivative, a dimeric structure was favored due to intermolecular interactions between the tin and oxygen atoms, in this case, the tin atom shows a distorted octahedral geometry. A computational study of the diethyl derivatives constructed from the available dibutyl structure, at DFT level, revealed that the main differences between the solid and gas phases are the geometry around the tin atom and the π-conjugated organic backbone which is nearly planar in the solid state and distorted in the gas phase. The electric field induced second-harmonic (EFISH) of the nonlinear optical (NLO) response for the dibutyl derivatives revealed that the change from boron to tin increases 1.5 times the hyperpolarizabilities (β).     

Photochromism of silver(I) and mercury(II) dithizonates : Effect of excess of free ligand on the return to ground state and effect of silver(I) dithizonate on the return of mercury(II) dithizonate

The energy of photons producing highest yield in the photochromic excitation of both silver(I) and mercury(II) dithizonate is shown to be centered around 520 nm. The effect of silver(I) dithizonate on the return of the excited form of mercury(II) dithizonate to the ground state is described. The accelerating effect of the silver complex is interpreted by an empirical kinetic model that takes into consideration the concurrent excitation and relaxation of both complexes. As observed in the photochromism of mercury(II) dithizonate, the presence of excess of ligand proportionally hastens the relaxation of silver(I) dithizonate to the ground state.     

Excess Molar Volume,Viscosity, and Molar Refraction Deviations,and Liquid–Vapor Equilibrium at 303.15 K for Chloroform + Acetonitrile Binary Mixture. An Infrared Study

Excess molar volume, viscosity deviation, and molar refraction deviation for the chloroform #x002B; acetonitrile system at 303.15 K were calculated from binary experimental results of density, viscosity, and refractive index over the whole mole fraction range, respectively. Isothermal vapor–liquid equilibrium data at the same temperature were also obtained and the excess molar Gibbs energy was calculated from these data. Each one of the properties was fitted to a Redlich–Kister type equation using least squares in order to obtain their dependencies on concentration. The presence of intermolecular association complexes was inferred from the viscosity deviations, leading to a 1:1 stoichiometric relationship. The recorded FTIR spectra confirm the existence of this type of hydrogen-bonded complex, making it possible, furthermore, to calculate the heteroassociation constant and enthalpy of formation of the hydrogen bond.     

A novel, compact disk-like centrifugal microfluidics system for cell lysis and sample homogenization

In this paper, we present the design and characterization of a novel platform for mechanical cell lysis of even the most difficult to lyse cell types on a micro or nanoscale (maximum 70 microL total volume). The system incorporates a machined plastic circular disk assembly, magnetic field actuated microfluidics, centrifugal cells and tissue homogenizer and centrifugation system. The mechanism of tissue disruption of this novel cell homogenization apparatus derives from the relative motion of ferromagnetic metal disks and grinding matrices in a liquid medium within individual chambers of the disk in the presence of an oscillating magnetic field. The oscillation of the ferromagnetic disks or blades produces mechanical impaction and shear forces capable of disrupting cells within the chamber both by direct action of the blade and by the motion of the surrounding lysis matrix, and by motion induced vortexing of buffer fluid. Glass beads or other grinding media are integrated into each lysis chamber within the disk to enhance the transfer of energy from the oscillating metal blade to the cells. The system also achieves the centrifugal elimination of solids from each liquid sample and allows the elution of clarified supernatants via siphoning into a collection chamber fabricated into the plastic disk assembly. This article describes system design, implementation and validation of proof of concept on two samples--Escherichia coli and Saccharomyces cerevisiae representing model systems for cells that are easy and difficult to lyse, respectively.     

Interaction of a two‐level cyclic XY n‐spin model with a two‐mode cavity field in off‐resonant states

The interaction of the XY n‐spin cyclic model with a two‐mode cavity field in the rotating‐wave approximation is investigated in the framework of a generalized Jaynes–Cummings two‐level system consisting of the vacuum state and a thermally averaged manifold of excited sates. Computation of the energy of this manifold allows this interaction to be examined in off‐resonant states. Time evolution of the population inversion, photon distribution, and temperature distribution for an excited initial state are computed via second‐ and third‐order perturbation expansion of the time evolution operator matrix elements for the excited and ground states, respectively and for an ideal squeezed initial coherent state of the cavity field. It was assumed that the two modes have initially the same photon distribution. The pattern of the spin population inversion appears as a manifestation of multiple and complicated inerferences, which is mathematically reflected in a double discrete summation that appears in the calculation of the dynamics. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008     

Transition metal coordination compounds of an antiobesity serotoninergic ligand: spectroscopic characterization and adipogenesis activity

Coordination compounds of cobalt(II), nickel(II), copper(II) and zinc(II) with L-5-hydroxytryptophan (L-5-HTP) were synthesized and characterized by elemental analysis, IR and UV–Vis-NIR spectroscopy, mass spectrometry and thermogravimetric analysis. The X-ray structure of the pure enantiomer ligand (L-5-HTP) was obtained. The ligand coordinates to the metal ions in an unidentate mode, where the donor atom is the oxygen from the carboxylic group. The intramolecular H-bond, N1H···O2, observed in the X-ray crystal structure of the free L-5-HTP, remains as a stabilization factor in all of the coordination compounds. Two types of geometries were adopted by the metal centers: tetrahedral and octahedral. In vitro antiadipogenic studies of the coordination compounds showed that the tetrahedral cobalt(II) and copper(II) complexes presented potential antiobesity properties.     

On the evolution equations for reduced density operators in quantum open systems

Evolution equations for transition probabilities of reduced density operators in quantum open systems are derived. Information contained in such equations is obtained from spectral resolutions and the role of memory kernels is elucidated within the scenario of many body theory as a function of the self-energy fields. As an analytical example of this formulation relaxation times for dissipative systems are evaluated in terms of the interaction between subsystems.     

Computational Study of Asian Propolis Compounds as Potential Anti-Type 2 Diabetes Mellitus Agents by Using Inverse Virtual Screening with the DIA-DB Web Server,Tanimoto Similarity Analysis,and Molecular Dynamic Simulation

Propolis contains a wide range of pharmacological activities because of their various bioactive compounds. The beneficial effect of propolis is interesting for treating type-2 diabetes mellitus (T2DM) owing to dysregulation of multiple metabolic processes. In this study, 275 of 658 Asian propolis compounds were evaluated as potential anti-T2DM agents using the DIA-DB web server towards 18 known anti-diabetes protein targets. More than 20% of all compounds could bind to more than five diabetes targets with high binding affinity (<−9.0 kcal/mol). Filtering with physicochemical and pharmacokinetic properties, including ADMET parameters, 12 compounds were identified as potential anti-T2DM with favorable ADMET properties. Six of those compounds, (2R)-7,4′-dihydroxy-5-methoxy-8-methylflavone; (RR)-(+)-3′-senecioylkhellactone; 2′,4′,6′-trihydroxy chalcone; alpinetin; pinobanksin-3-O-butyrate; and pinocembrin-5-methyl ether were first reported as anti-T2DM agents. We identified the significant T2DM targets of Asian propolis, namely retinol-binding protein-4 (RBP4) and aldose reductase (AKR1B1) that have important roles in insulin sensitivity and diabetes complication, respectively. Molecular dynamic simulations showed stable interaction of selected propolis compounds in the active site of RBP4 and AKR1B1. These findings suggest that Asian propolis compound may be effective for treatment of T2DM by targeting RBP4 and AKR1B1.     

Photolithographic Patterning of a Conductive Polymer Using a Polymeric Photoacid Generator and a Traceless Removable Group

Summary: In the present communication we describe a photolithographic method to produce polyaniline (PANI) patterns using PANI modified with a traceless removable functional group (nitrosated polyaniline, PANI‐NO) and external inexpensive polymeric photoacid generators (poly(vinyl chloride), PVC). Therefore, residual sub‐products created by irradiation of the plate do not remain occluded in the polymeric films. The borders of the patterns are better defined than in the case of chemical lithography using inorganic acids as the hydrolyzing agent.

     

Evaluation of Traumatic Spinal Cord Injury in a Rat Model Using 99mTc-GA-5 as a Potential In Vivo Tracer

Spinal cord injury (SCI) refers to the damage suffered in the spinal cord by any trauma or pathology. The purpose of this work was to determine whether ^99mTc-GA-5, a radiotracer targeting Glial Fibrillary Acidic Protein (GFAP), can reveal in vivo the reactivation of astrocytes in a murine model with SCI. A method for the ^99mTc radiolabeling of the mouse anti-GFAP monoclonal antibody GA-5 was implemented. Radiochemical characterization was performed, and radioimmunohistochemistry assays were used to evaluate the integrity of ^99mTc-GA-5. MicroSPECT/CT was used for in vivo imaging to trace SCI in the rats. No alterations in the GA-5’s recognition/specificity ability were observed after the radiolabeling. The GA-5’s radiolabeling procedure implemented in this work offers a practical method to allow the in vivo following of this monoclonal antibody to evaluate its biodistribution and specificity for GFAP receptors using SPECT/CT molecular imaging.