Optical Rotatory Dispersion of Poly(propylene oxide) in Benzene Solution Determined from Channeled Spectra

The proposed method of channeled spectrum employs the recorded channeled spectrum of an optical active polymer solution placed between two crossed polarizers. The approach allows the evaluation of the optical rotatory dispersion of poly(propylene oxide) in benzene. The specific rotation, circular birefringence, and dispersion parameter depend on the wavelengths of the maxima and minima from the channeled spectrum.     

Novel fluorescence nanostructured materials obtained by entrapment of an ornamental bush extract in hybrid silica glass

Synthesis of some novel fluorescence nanomaterials loaded with photoactive polyphenols originated from plants with a high spectrum of biological activity, by replacing synthetic chemicals, may open new opportunities for optical and bio-medical applications. This paper presents the synthesis, characterization and fluorescence properties of a new class of materials based on host hybrid matrices obtained through templated sol–gel route, by hydrolysis and co-condensation of tetraorthoethylsilicate with octaisobutyltetracyclo [7.3.3.1^5,11] octasiloxane-endo-3,7-diol. The aim of paper is focused on the evaluation of the behavior of the fluorescence properties of ornamental bush extract at immobilization in a templated silica matrix and in a silica-silsesquioxane network, using as templates a neutral, non-toxic and biodegradable surfactant from poly(ethyleneglycol) class and a high biocompatible non-surfactant from glucidic class. The proofs of ornamental bush extract entrapment by physical interactions in silica based networks were provided by FT-IR and UV–VIS spectroscopy. The changes of polymer network due to the hydrogen bond interactions between residual Si–OH groups and functional groups of organic molecules from extract were evidenced by shifts of specific vibrations. In UV–VIS-NIR domain, the chromophore groups from ornamental bush extract were also evidenced by similar small shifts. As a result of ornamental bush extract entrapment, in all the immobilized samples the fluorescence intensity was more than 10 times amplified in samples templated with poly(ethylenglycol) surfactant) and of about 5 times in samples with glucidic template due to the physical adsorption of polyphenolic molecules from extract, excellent synergistic optical properties of SiO₂ and silsesquioxane compound and also due to a favorable conformational arrangement. The size of synthesized polymeric materials, estimated by dynamic light scattering technique showed main diameters less then 1.4 μm, namely 1,060 and 211 nm—for samples with d-glucose template and 1,330 and 531 nm—for samples with poly(ethyleneglycol) template, respectively, with a narrow size distribution and a polidispersity varying between 0.022 and 0.426. These results are in good accordance with TEM images that evidenced the presence of some polymeric aggregates which contain the vegetal extract immobilized inside hybrid SiO₂-Sq polymeric network of about hundred nanometers size. This study bring new contributions to the development of the sol–gel procedure by entrapment of a complex vegetable mixture in polymeric matrices as integral component of silica and hybrid silica-silsesquioxane networks which leads to a significant enhancement of the functional properties of the final material, thus diversifying the potential applications of organic doped sol–gel glasses.     

BEM-Fading regularization algorithm for Cauchy problems in 2D anisotropic heat conduction

Numerical Algorithms - We investigate the numerical reconstruction of the missing thermal boundary data on a part of the boundary for the steady-state heat conduction equation in anisotropic solids...     

Reactivity of N-cyanoalkyl-substituted imidazolium halide salts by simple elution through an azide anion exchange resin

Certain N-cyanoalkyl-functionalized imidazolium halide salts unexpectedly undergo nitrile hydrolysis to amides, as well as dipolar cycloaddition to tetrazoles when eluted on azide anion exchanged resin.     

Enzyme-catalyzed synthesis of (R)- and (S)-3-hydroxy-3-(10-alkyl-10H-phenothiazin-3-yl)propanoic acids

Starting from the racemic ethyl 3-hydroxy-3-(10-alkyl-10H-phenothiazin-3-yl)propanoates as substrates, a multienzymatic procedure was developed for the efficient synthesis of the corresponding highly enantiomerically enriched (R)- and (S)-3-heteroaryl-3-hydroxypropanoic acids.     

Triazene UV-triggered photogeneration of silver/gold nanoparticles in block copolymer templates

Journal of Nanoparticle Research - Synthesis of yttrium oxide nanoparticles in a specially designed radio frequency thermal plasma reactor is reported. Good crystallinity, narrow size distribution,...     

Cocycles on a finite dimensional quotient of uq (sl(2))

We prove that certain algebra quotients of Hopf algebras are twisted Hopf algebras. On the other handu_q (sl(2)) is a crossed product of a central subalgebra with a quotient [Ubar], when q is a root of 1. Using the cocycle involved in this crossed product we construct non-trivial complex cocycles τ and we find the isomorphism classes of the corresponding twisted Hopf algebras _τ [Ubar]. These provide complex projective representations of [Ubar] which are not ordinary representations.     

Transition and post-transition metal ion chemistry of dibenzo-substituted,mixed-donor macrocycles incorporating five donor atoms

The transition and post-transition metal ion chemistry of a wide range of potentially pentadentate dibenzo-substituted macrocyclic ligands incorporating nitrogen, oxygen and/or sulfur donors is reviewed and shown to result in a diverse range of structural types. Aspects of metal ion recognition, bulk membrane transport, systems incorporating appended chromophores, a sulfate binding system, induced Cu(I)/Cu(II) redox switching, coordination polymers, and unsymmetric macrocyclic ligand systems are all discussed.     

N,N′‐Methylenediimidazolium Salts: From Self‐Assembly to an Efficient DNAse Protection System

We have developed N,N′‐dialkylmethylenediimidazolium salts ([C_nC_nDIM][X]₂) that self‐organize into multilayered cationic vesicles and can interact with DNA. These preorganized systems form complexes with linear DNA and protect it from DNase I cleavage.