Reinvestigation of liquid crystalline property of dimesogenic compound consisting of cholesterol and cyanobiphenyl

The dimesogenic compound consisting of cholesterol and cyanobiphenyl mesogens interlinked byω-oxyalkanoyl spacer was synthesized.The mesomorphic properties were investigated by differential scanning calorimetry(DSC),polarizing optical microscopy(POM),and X-ray diffraction(XRD).The experimental results indicated that this compound exhibited mesophase over a much wider temperature range and a new mesophase blue phase(BP).Focal conic domains(FCDs) and droplets texture to the smectic A phase(SA),oily streaks...     

SYNTHESIS OF AMPHIPHILIC COMB-SHAPED COPOLYMERS USED FOR SURFACE MODIFICATION OF PVDF MEMBRANES

The synthesis of a novel amphiphilic comb-shaped copolymer consisting of a main chain of styrene-(N-(4- hydroxyphenyl) maleimide)(SHMI) copolymer and poly(ethylene glycol) methyl ether methacrylate(PEGMA) side groups was achieved by atom transfer radical polymerization(ATRP).The amphiphilic copolymers were characterized by ~1H-NMR, Fourier transform infrared(FTIR) spectroscopy and gel permeation chromatography(GPC).From thermogravimetric analysis (TGA),the decomposition temperature of SHMI-g-PEGMA is low...     

Periodic minimizers of the anisotropic Ginzburg–Landau model

We consider the anisotropic Ginzburg–Landau model in a three-dimensional periodic setting, in the London limit as the Ginzburg–Landau parameter \({\kappa=1/{\epsilon}\to\infty}\) . By means of matching upper and lower bounds on the energy of minimizers, we derive an expression for a limiting energy in the spirit of Γ-convergence. We show that, to highest order as \({\epsilon\to0}\) , the normalized induced magnetic field approaches a constant vector. We obtain a formula for the lower critical field H _c1 as a function of the orientation of the external field \({h^\epsilon_{ex}}\) with respect to the principal axes of the anisotropy, and determine the direction of the limiting induced field as a minimizer of a convex geometrical problem.     

On the structure of fractional degree vortices in a spinor Ginzburg-Landau model

We consider a Ginzburg-Landau functional for a complex vector order parameter Ψ=(ψ₊,ψ₋), whose minimizers exhibit vortices with half-integer degree. By studying the associated system of equations in R² which describes the local structure of these vortices, we show some new and unconventional properties of these vortices. In particular, one component of the solution vanishes, but the other does not. We also prove the existence and uniqueness of equivariant entire solutions, and provide a second proof of uniqueness, valid for a large class of systems with variational structure.     

Separation of Aromatic Carboxylic Acids in IC and the Study on the Relationship Between Retention Behavior and Electrostatic Potential

A method has been developed for separation of 20 kinds of aromatic carboxylic acid using anion-exchange chromatography. A Dionex IonPac AS9-HC guard column (250mm×2mm) was used with a 9mmol/L sodium carbonate solution containing 50% (v/v) acetonitrile as eluent. A set of retention time data has been obtained using a conductivity detector DS6. Furthermore, geometrical optimization and electrostatic potential calculation of 20 kinds of aromatic carboxylic acid have been performed at the HF/6-31G* level of theory. A number of statistically-based parameters derived from molecular surface electrostatic potential have been obtained. Linear relationship between retention time and structural parameters has been established by multiple regression method. The result shows that parameters derived from electrostatic potential Vs +, Vs -, П together with the dipole moment μ can be well used to express the quantitative structure-retention time of this kind of aromatic carboxylic acid. Good predictive capability has also been demonstrated. The result has provided a framework which further proves the general applicability of this electrostatic potential parameter set to a great extent,and with which the ion chromatographic adsorption mechanism can be investigated.     

Self-assembled multilayers of transition-metal-terpyridinyl complexes; formation, and characterization

Layer-by-layer (LBL) growth of terpyridinyl ligands with a range of metal ions is reported. Monolayers of mercaptophenyl terpyridine on gold were used to initiate LBL assembly by complexing the first layer of metal ions. Tetra-2-pyridinylpyrazine was used as a linking ligand between subsequent metal ion layers. The assembly of the terpyridines with 21 different metals was evaluated using UV absorbance spectroscopy, variable-angle spectroscopic ellipsometry, and atomic force microscopy. Successful LBL growth appears to depend on the ionic radius of the metal ion. Metals that formed multilayered LBL structures were primarily limited to a small range of effective ionic radii between 66 and 73 pm. Metal ions with smaller ionic radii usually formed initial layers but seldom exhibited consistent LBL growth, while ions with radii larger than 73 nm generally did not demonstrate any evidence of LBL growth.     

Antibacterial and Photocatalytic Properties of ZnO Nanoparticles Obtained from Chemical versus Saponaria officinalis Extract-Mediated Synthesis

In the present work, the properties of ZnO nanoparticles obtained using an eco-friendly synthesis (biomediated methods in microwave irradiation) were studied. Saponaria officinalis extracts were used as both reducing and capping agents in the green nanochemistry synthesis of ZnO. Inorganic zinc oxide nanopowders were successfully prepared by a modified hydrothermal method and plant extract-mediated method. The influence of microwave irradiation was studied in both cases. The size, composition, crystallinity and morphology of inorganic nanoparticles (NPs) were investigated using dynamic light scattering (DLS), powder X-ray diffraction (XRD), SEM-EDX microscopy. Tunings of the nanochemistry reaction conditions (Zn precursor, structuring agent), ZnO NPs with various shapes were obtained, from quasi-spherical to flower-like. The optical properties and photocatalytic activity (degradation of methylene blue as model compound) were also investigated. ZnO nanopowders’ antibacterial activity was tested against Gram-positive and Gram-negative bacterial strains to evidence the influence of the vegetal extract-mediated synthesis on the biological activity.     

Crystal Structures of Two New Monoprotonated Products of 1,4,7 trimethyl-1,4,7-triazacyclononane: (Me_3〔9〕aneN_3H)(SO_3CF_3) and (Me_3〔9〕aneN_3H)I

１　ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｓａｔｕｒａｔｅｄｍａｃｒｏｃｙｃｌｅｓｔｒｉａｚａｃｙｃｌｏｎｏｎａｎｅ（〔９〕ａｎｅＮ３）ａｎｄ１,４,７－ｔｒｉｍｅｔｈｙｌ－１,４,７－ｔｒｉａｚａｃｙｃｌｏｎｏｎａｎｅ（Ｍｅ３〔９〕ａｎｅＮ３）ａｒｅｍｅｍｂｅｒｓｏｆａｆａｍｉｌｙｏｆｐｏｔｅｎｔｉａｌｌｙｔｒｉ－ｄｅｎｔａｔｅｍａｃｒｏｃｙｃｌｉｃｌｉｇａｎｄｓｗｈｉｃｈｆｏｒｍｔｈｅｒｍｏｄｙｎａｍｉｃａｌｌｙａｎｄｋｉｎｅｔｉｃａｌｌｙｓｔａｂｌｅｃｏｍｐｌｅｘｅｓｗｉｔｈｈｅａｖｉｅｒｍａｉｎ…     

Tuning a Bisphenol A Lateral Flow Assay Using Multiple Gold Nanosystems

Advanced bisphenol A (BPA) lateral flow assays (LFAs) that use multiple nanosystems are reported. The assays use three nanosystems: gold nanostars, gold nanocubes, and gold nanorods, which are rarely applied in LFAs, compared with general gold nanoparticles that are referred to as gold nanospheres in this paper. These various nanosystems are bound to anti‐BPA antibodies and applied in LFAs to develop advanced BPA LFAs; the developed LFAs show differing BPA detection performance, as well as different visible colors, optical intensities, limits of detection, and application ranges. Advanced BPA LFAs that use multiple gold nano‐object shapes are successfully developed, and the geometry effects of diverse gold nanosystems coupled with anti‐BPA antibodies and the potential applications of regular BPA LFAs are explored.     

4,4’-trimethylenedipiperidine as a nitrogen heterocycle solvent and/or catalyst: Liquid phase tandem Knoevenagel–Michael condensation

Liquid phase tandem Knoevenagel–Michael condensation of various aromatic and heteroaromatic aldehydes with barbituric acid or 2-thiobarbituric acid and malononitrile was studied in a one-pot three-component reaction. For the first time, TMDP was employed as a safe and efficient solvent and/or catalyst in the liquid and aqueous ethanol medium, respectively, for the practical and eco-friendly Knoevenagel–Michael condensation. The reactions were carried out by using greener procedures, including a) the use of TMDP as an N-heterocycle organocatalyst in a green medium including water and ethanol (1:1 v/v) at reflux temperature, and b) the use of TMDP as a dual solvent-catalyst at 65 °C in the absence of any solvent. High to excellent yields of the desired pyrano[2,3- d ]pyrimidinones were obtained under the two earlier mentioned conditions. The current methodologies have advantages, including (a) avoiding hazardous, toxic, volatile, and flammable materials and solvents, (b) avoiding tedious processes, harsh conditions, and multiple steps for the preparation of catalysts, (c) using a less toxic and noncorrosive catalyst, (d) minimizing hazardous waste generation and simple workup process, and (e) high recyclability of TMDP. Another important result of this work is that the TMDP can be a promising alternative for toxic, volatile, and flammable base reagents such as piperidine and triethylamine in liquid phase organic syntheses owing to its unique properties such as being less toxic, nonflammable, and nonvolatile, and having a low melting point, broad liquid range temperature, high thermal stability, and safe handling and storage.