Guest host interaction in the compensated cholesteric mixture of cholesteryl chloride and cholesteryl laurate 74:26% molar

The colour effect appearing in a compensated binary cholesteric mixture is described in the presence of two dyes — Rhodamine 6G and a cumilphenol azo dye derivative     

Thyroid cancers

We have analysed factors that influenced on the patient survival in 195 cases of thyroid cancer. The survival is essentially influenced by the histology, the papillary forms (survival after 15 years: 83.1-93%) and follicular cancers (survival after 15 years: 84-94%) having an excellent evolution. The non-differentiated and mixed cancers have a very severe prognosis that is independent of the complex therapy that have been used (survival after 5 years: 17.1% in non-differentiated forms and 32.5% in mixed ones). The prognosis is better in subjects under the age of 45 and in female subjects. The cancers in the 1-st and 2-nd stage of tumor extension have a better evolution that those in the 3-rd stage. In differentiated cancers, the total or subtotal thyroidectomy followed by radioiodine administration determine the best survival.     

The compatibility of the polystyrene/acrylonitrile-butadiene-styrene grafted copolymer system

Summary The study of polystyrene (PS)/acrylonitrile-butadiene-styrene (ABS) grafted copolymer/cyclohexanone or methylene chloride system compatibility both in concentrated solutions and solid state has been carried out by phase separation, viscosimetrical measurements and thermal behaviour.Having in view the obtained data it has been ascertained that the systems present different degrees of compatibility depending on the mixtures composition. At higher temperatures, the compatibility of the components is changed.     

Highly Crosslinked Polysilane–Schiff Base

Summary N,N-Bis(4-hydroxysalicylidene)ethylendiamine (salen) was attached to a poly[iodopropyl(methyl)-co-diphenylsilane)chain. Due to intermolecular crosslinking reactions, a high molecular weight polymer formation was observed. The resulted material was doped with metal cations through complexation reactions. The chemical structure of the polysilane-Schiff base metal complex was investigated by spectral analysis (IR, ¹H-NMR, ¹³C-NMR, UV), thermogravimetric analysis (TGA) and gel permeation chromatography (GPC).     

A Michael-type reaction between acrylato ions and ethylenediamine coordinated to Ni(II). Synthesis,crystal structure and magnetic properties of [Ni2(EDDP)2(H2O)2] · 2H2O (H2EDDP = ethylenediamine-N,N-dipropionic acid)

The reaction between NiCO₃ · Ni(OH)₂, acrylic acid and ethylenediamine in a 2:4:1 molar ratio affords the binuclear complex, [Ni₂(EDDP)₂(H₂O)₂] · 2H₂O 1. The organic ligand, EDDP^2? (the dianion of the ethylenediamine-N,N-dipropionic acid ligand), results from the addition of one amine group to the carbon–carbon double bonds of two acrylato ions. The crystal structure of 1 consists of neutral centrosymmetric entities, with the nickel ions connected by two carboxylato groups, each one acting as a monoatomic bridge. The intramolecular Ni?Ni distance is 3.212 Å. The metal ions exhibit an octahedral geometry. The cryomagnetic investigation of 1 reveals an antiferromagnetic coupling of the nickel(II) ions (J = ?21.8 cm^?1, H = ?JS_Ni1S_Ni2).     

Effect of hydrolyzed collagen on thermal,mechanical and biological properties of poly(lactic acid) bionanocomposites

Iranian Polymer Journal - Bionanocomposites based on poly(lactic acid) (PLA), plasticized with commercial tributyl o-acetyl citrate (ATBC) and containing hydrolyzed collagen (HC) up to...     

Anticorrosive coating based on poly(vinyl acetate) formed by electropolymerization on the copper surface

The poly(vinyl acetate) (PVAC) film was obtained by electropolymerization on the copper electrode using cyclic voltammetry performed in mixed electrolyte based on water/ethyl alcohol/acetic acid containing vinyl acetate (VAc) and benzoyl peroxide as polymerization initiator. The coatings were characterized by optical microscopy, scanning electron microscopy (SEM) and infrared (IR) spectroscopy. The corrosion was induced in hydrochloric acid solution using potentiodynamic measurements and electrochemical impedance spectroscopy (EIS). The microscopic and SEM images revealed the PVAC coating formation and IR spectroscopy confirmed that it exhibits the same characteristic bands as a standard PVAC sample. From the potentiodynamic polarization, the PVAC protective performance of 78% was computed. The EIS measurements showed the occurrence of the surface adsorbed layer with a higher impedance response to the frequency and a phase angle maximum shifted to lower values than those of uncoated samples. In addition, the VAc electropolymerization mechanism was discussed and the PVAC adsorption mechanism on the copper surface was proposed. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47320.     

The Effect of the Ionizing Radiation on Hydroxyapatite–Polydimethylsiloxane Layers

The bio hydroxyapatite (HAp) was used from a long time in different medical and environmental applications. The HAp layers with a uniform surface were used for various medical applications such as orthopedic and dental metal implants. In this work, we reported on the influence of X‐ray radiation on the structural and morphological properties of composite layers based on HAp and polydimethylsiloxane (PDMS) deposited on titanium substrates. The HAp:PDMS layers were investigated by different complementary methods such as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and glow discharge optical emission spectrometry (GDOES). FTIR spectral analysis showed that the molecular structure of the coatings was not changed after their irradiation even though, the depth profile analysis performed by GDOES indicated a depletion of Ca and P elements from the HAp:PDMS irradiated samples. By SEM, we showed that the morphological features of the coatings were also changed, as the irradiated layers are delaminated. The biological assays confirmed that the antibacterial activity of HAp:PDMS composite layers increased after irradiation. The results obtained in this study highlighted that the biological properties of HAp:PDMS layers could be influenced by irradiation. POLYM. ENG. SCI., 59:2406–2412, 2019. © 2019 Society of Plastics Engineers     

3D multi-material and multi-joint topology optimization with tooling accessibility constraints

Structural and Multidisciplinary Optimization - This paper proposes a method for performing both multi-material topology optimization and multi-joint topology optimization. The algorithm can...     

Biosynthesis of silver nanoparticles in collagen gel improves their medical use in periodontitis treatment

Silver nanoparticles (AgNP) suspensions were biosynthesized by silver ions reduction in the presence of collagen, a nontoxic, organic polymer, intending to improve their medical use in periodontitis treatment. Spectrophotometric measurements showed a time- and concentration-dependent increase of AgNP formation in each suspension variant. Transmission electron microscopy revealed spherical morphology of AgNP in collagen and their mean diameter size was around 30?nm. The particle size distribution and zeta potential values of AgNP in collagen were determined by dynamic light scattering measurements. The surface charge of AgNP in collagen was positive, while commercial AgNP stabilized in citrate had negative surface charge. In vitro cytotoxicity testing of AgNP in collagen showed that they were biocompatible with human gingival fibroblasts in a wider range of concentrations than commercial nanoparticles. The antibacterial activity of AgNP in collagen against two pathogenic strains present in the periodontal pocket was dose-dependent and higher than that of AgNP in citrate. All these results demonstrated that AgNP prepared in collagen gel had improved properties, like small diameter, positive surface charge, high biocompatibility in human gingival fibroblasts, efficiency against bacterial growth and, thus, better therapeutic potential in periodontal disease treatment.