Modular Columnar Supramolecular Polymers as Scaffolds for Biomedical Applications

Self‐assembly of discotic molecules into supramolecular polymers offers a flexible approach for the generation of multicomponent one‐dimensional columnar architectures with tuneable biomedical properties. Decoration with ligands induces specific binding of the self‐assembled scaffold to biological targets. The modular design allows the easy co‐assembly of different discotics for the generation of probes for targeted imaging and cellular targeting with adjustable ligand density and composition.     

Triphosph(III)azanes to diphosph(III)azanes; a cracking transformation

The reversible interconversion between trimeric [ClPNEt]3 and dimeric [ClPNEt]2 reported here is the first observation of such a thermally induced rearrangement between two cyclophosphazane oligomers; the structure of 1.cis is reported along with NMR studies of its conversion into 2.     

Antibiofilm,Anti-Quorum Sensing Activities,and Molecular Docking Studies of Seriphidium quettense Essential Oil

Chemistry of Natural Compounds -     

Determination of ammonium,calcium, magnesium,potassium and sodium in drinking waters by capillary zone electrophoresis on a column-coupling chip

This work deals with simultaneous determination of ammonium, calcium, magnesium, sodium and potassium in drinking waters by capillary zone electrophoresis (CZE) on a column-coupling (CC) chip with suppressed hydrodynamic and electroosmotic transports. CZE separations were carried out in a propionate background electrolyte at a low pH (3.2) containing 18-crown-6-ether (18-crown-6) to reach a complete resolution of the cations. In addition, triethylenetetramine (TETA) coated the inner wall surface of the chip channels. The concentration limits of detection (cLOD) for the studied cations ranged from 4.9 to 11.5 μg/l concentrations using a 900 nl volume of the sample injection channel. 93–106% recoveries of the cations in drinking waters indicate a good predisposition of the present method to provide accurate analytical results.     

Effect of weak rotation on natural convection in a horizontal porous cylinder

Natural convection in a fluid saturated porous medium confined in a horizontal circular cylinder and rotating about its axis, with isothermal boundary conditions and uniform internal heat sink, is studied by both numerical and perturbation methods. No symmetry with respect to the vertical diameter is expected for the flow and temperature fields and the whole region must be involved in the computation. Only the weak rotation regime, for which the centrifugal force is negligible compared to gravity, is considered. Governing equations for the two-dimensional flow field are solved in both rotating and non-rotating coordinate systems. Results indicate that rotation significantly decreases the radial amplitude of fluid particle trajectories in the radial direction and thus reduces the overall heat transfer.     

Application of cylindrical near-field acoustical holography to the visualization of aeroacoustic sources

The purpose of this study was to develop methods for visualizing the sound radiation from aeroacoustic sources in order to identify their source strength distribution, radiation patterns, and to quantify the performance of noise control solutions. Here, cylindrical Near-field Acoustical Holography was used for that purpose. In a practical holographic measurement of sources comprising either partially correlated or uncorrelated subsources, it is necessary to use a number of reference microphones so that the sound field on the hologram surface can be decomposed into mutually incoherent partial fields before holographic projection. In this article, procedures are described for determining the number of reference microphones required when visualizing partially correlated aeroacoustic sources; performing source nonstationarity compensation; and applying regularization. The procedures have been demonstrated by application to a ducted fan. Holographic tests were performed to visualize the sound radiation from that source in its original form. The system was then altered to investigate the effect of two modifications on the fan's sound radiation pattern: first, leaks were created in the fan and duct assembly, and second, sound absorbing material was used to line the downstream duct section. Results in all three cases are shown at the blade passing frequency and for a broadband noise component. In the absence of leakage, both components were found to exhibit a dipole-like radiation pattern. Leakage was found to have a strong influence on the directivity of the blade passing tone. The increase of the flow resistance caused by adding the acoustical lining resulted in a nearly symmetric reduction of sound radiation.     

4,5-Bis(diphenylthiophosphinoyl)-1,2,3-triazolate interaction with gold nanoparticles and flat surfaces to form self-assembled monolayers

The interaction of the 4,5-bis(diphenylthiophosphinoyl)-1,2,3-triazolate (SPTz⁻) with different gold surfaces was investigated (nanoparticles, an electrode, and flat sheets). Studies on binding affinity of this dithiophosphin-triazolate on a gold electrode were performed by cyclic voltammetry (CV). Voltammograms exhibit two reductive desorption and only one oxidative readsorption, indicating that once reabsorbed, the molecule achieves a unique conformation. The morphology and average size of modified gold nanoparticles were studied by transmission electron microscopy (TEM) (av. diameter of 5.9 ± 1.8 nm). Further characterization was made by UV-visible (UV-vis) spectroscopy showing surface plasmon resonance (SPR) at about 580 nm. The bonding configurations of SPTz⁻ on gold have also been investigated by comparing the FT-IR and FT-Raman spectra. The ³¹P{¹H} NMR spectrum of capped nanoparticles exhibited two sharp signals at 30.3 and 29.6 ppm and a very broad signal at 72.7 ppm. X-ray photoelectron spectroscopy (XPS) showed SPTz⁻ can accomplish a strong interaction with gold nanoparticles through bonds involving a sulfur atom and a nitrogen from the triazole ring with a free terminal PS group, forming self-assembled monolayers (SAM). This may allow subsequent functionalization through free S/N atoms of the formed SAMs. The SPTz⁻ packing led to a reduction in packing density that permits large spaces between adsorbed headgroups and the inclusion of carbon and oxygen impurities from small molecules; nevertheless, oxidized sulfur or nitrogen species were not detected, indicating the chemical stability of the obtained SAMs.     

Evaluation of the enantioselective binding of imazalil to human serum albumin by capillary electrophoresis

In this work, a methodology for the evaluation of enantioselective binding of imazalil (IMA) enantiomers to human serum albumin (HSA) that does not require the separation of free and bound to HSA fractions is developed. This methodology comprises the incubation of IMA–HSA designed mixtures for 30 min directly in the capillary electrophoresis system and the subsequent direct injection and chiral separation of IMA employing highly sulfated β‐cyclodextrin as chiral selector and the complete filling technique. Two mathematical approaches were used to estimate apparent affinity constants (K₁), protein binding and enantioselectivity (ES) for both enantiomers of IMA. Moderate enantioselective binding of IMA enantiomers to HSA (ES = 2.0) was shown by the 1:1 stoichiometry and log K₁ values of 3.4 ± 0.4 and 3.1 ± 0.3 for the first and second eluted enantiomers, respectively. Copyright © 2015 John Wiley & Sons, Ltd.