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A platinum(II) complex of 3-amino-1,2,4-triazole is synthesized and characterized by using 1H, 13C NMR and FT-IR spectroscopies. The molecular geometry and the chemical reactivity of the complex are studied using the Density Functional Theory at B3LYP/6-311++G(d,p) basis set of H, C, N, Cl and LANL2DZ for Pt. The molecular electrostatic potential surface, the natural bond orbital and the natural charge population are estimated. The frontier molecular orbital analyses are conducted. The intramolecular interactions in [Pt(3-amino-1,2,4-triazole)2Cl2] are investigated using the quantum theory Atoms in Molecules. It is observed that the complex is stabilized via two hydrogen bonds, N–H···Cl, which are weak and electrostatic in nature. They determine the different energy and bond length of Pt–Cl and Pt–N. The compound cytotoxicity is evaluated using 2 type eukaryotic cells: MDCK II kidney epithelial cell line and A549 cancer alveolar cell line. The results of this investigation demonstrate the high cytotoxic effect of [Pt(3-amino-1,2,4-triazole)2Cl2] especially to cancer cells. This Pt(II) complex is a promising nanomaterial for a variety of biomedical applications, including cancer therapy [ABSTRACT FROM AUTHOR]

Bioactive glass was first synthesized by L. Hench in 1971. There are many studies on the properties of several metals and metal ions dopants used in the SiO2‐CaO‐P2O5 system of bioglasses, such as Ag, Cu, Zn, and Fe. A number of authors have carried out research related to the influence of silver oxide on the properties of bioglasses. However, publications on the properties of elastomer‐based composites containing bioactive glasses are relatively scarce. We have not found in the literature studies discussing how silver oxide concentration in bioglasses of the CaO‐SiO2‐P2O5‐Ag2O system affects the significant properties of a natural rubber biocomposite. In this regard, the purpose of the present work is to investigate the aforementioned influence on the properties of this type of composites, namely, vulcanization, physicomechanical, thermal, dynamic, dielectric, electric, and thermoconductive characteristics. We have established those parameters of the composites to be impacted considerably by both degree of filling with bioglass and the silver oxide content in the latter. The improvement in the composites thermostability and some of their physicomechanical performance is the most significant. The volume resistance decreases, and the thermal conductivity coefficients increase. Results from scanning electron microscopy and energy‐dispersive X‐ray (EDX) analyses have confirmed the influence of silver oxide initially on the phase composition of the bioglass, hence on the properties of the biocomposites through changes in the bioglass used as filler. The dielectric characteristics of some of the biocomposites suggest that they can be used as substrates and insulating layers in flexible antennas for short‐range wireless communications. [ABSTRACT FROM AUTHOR]

The study examines the phase composition and structure of fayalite waste (FW), as well as the changes that occur during heat treatment applied in the temperature range of 500 - 1000 °C. Differential thermal analysis, X-Ray diffraction analysis, Fourier transform infrared spectroscopy, Optical microscopy, Scanning electron microscopy and Energy dispersive spectroscopy have been used. The main crystalline phase in waste was fayalite, accompanied by magnetite, amorphous silicate phase and a small amount of copper-iron sulfides. Phase-structural changes were found in all heat treated samples. Their extent was temperature dependent. Fayalite transformed to hematite, magnetite and silica. Magnetite transformed to hematite through oxidation. Glass phase underwent oxidation too. In oxidation at 1000°C FW baseline phases were fully replaced by hematite, magnetite, cristobalite and amorphous silicate phase. At this heat treatment temperature the sample exhibited the highest catalytic activity towards the oxidation of CO. [ABSTRACT FROM AUTHOR]

Several types of glass-ceramics in the CaO - MgO - SiO2 system are shown to be bioactive, biocompatible and exhibiting various advantages for bone regeneration. A polyphase calcium-magnesium-silicate glass-ceramics is prepared by the sol-gel method including a two-step thermal treatment procedure aiming to investigate the effect of its phase composition on the in-vitro bioactivity observed. The dried gels of a chemical composition 3CaO.MgO.2SiO2 corresponding to merwinite are thermally treated at 700°C and 1100°C. The structural behavior of the synthesized samples is examined by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). Larnite as the main crystalline phase, accompanied by merwinite, akermanite and periclase are detected after heat treatment at 1100°C. The in-vitro bioactivity of the glass-ceramics is detected by investigating the apatite formation ability in Simulated Body Fluid (SBF) for different times of soaking. The changes on the surface of the immersed samples and the formation of Mg- and Si-substituted carbonated apatites are verified by FTIR, SEM and Energy Dispersive Spectroscopy (EDS) techniques. The dissolution behavior of the glass-ceramics in SBF is also carried out by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The results indicate fast degradation in SBF and high reactivity of the polyphase glass-ceramics. The latter might be used as a bioactive implant material. [ABSTRACT FROM AUTHOR]

In the present work Polyurethane (PU)/Bioglass (BG) composite materials were synthesized with different content of BG (10 and 20 mol.%) as filler. The 85S Bioglass was synthesized via polystep sol-gel method. The chemical composition of BG is 85SiO-10CaO-5PO (wt.%). The synthesis of PU was carried out by a two-step polyaddition reaction. The 85S BG was added in situ during the polymerization reaction. In vitro bioactivity of the prepared composites was examined in the presence of 1.5 SBF for 7 days in static conditions. The structure of synthesized PU/BG composites before and after in vitro test was determined by XRD, FTIR and SEM. XRD of the samples before in vitro test proved that the phase of γCaPO in the PU/20BG is visible. FTIR revealed the presence of urethane bond between OH-(from BG) and NCO groups (from PU). Based on FTIR results after in vitro test in 1.5 SBF solutions, A/B-carbonate containing hydroxyapatite (COHA) was formed. XRD proved that HA was formed on the surface of the samples, but CaPO does not undergo any changes in the 1.5 SBF solution. SEM depicted the nano-HA agglomerated in spherical particles after immersion in 1.5 SBF for 7 days. [ABSTRACT FROM AUTHOR]

The present work investigates surface biocompatibility of silicon-substituted calcium phosphate ceramics. Different silicon-substituted calcium phosphate ceramic bodies were prepared from co-precipitated powders by sintering at 1300°C. The in vitro bioactivity of the ceramics was assessed in simulated body fluid (SBF) at 37°C for periods up to 4 weeks. The changes in the surface morphology and composition were determined by scanning electron microscopy (SEM) coupled with electron probe microanalysis and energy dispersive spectrometer (EDX). Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to observe the change in ionic concentration of SBF after removal of the samples. The bioactivity of the ceramics increased with an increasing silicate ion substitution in a systematic way. The surface of ceramics with 2.23% silicon substitution was partially covered with apatite layer after one week, while ceramics with 8.1% silicon substitution were completely covered with apatite in the first week. The porous microstructure of high-concentration Si-substituted ceramics helps the dissolution of surface ions and the leaching process. This allows SBF to reach supersaturation in a short time and accelerate the deposition of apatite layer. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Methylcellulose (MC) / SiO organic / inorganic hybrid materials have been prepared from MC and methyltriethoxysilane or ethyltrimethoxysilane, and characterized by XRD, FTIR and AFM. XRD showed peak shifts. FTIR shows intermolecular hydrogen bonding between MC and SiO. AFM depicts surface roughness which depends on the silica precursor and MC content. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Mono – (Ag/SiO2, Pd/SiO2) and bimetallic (Ag+Pd/SiO2) catalysts have been obtained via sol-gel method from tetra-ethoxy-silane (TEOS) and their activity in reduction of Nitric oxide (NO) with carbon monoxide (CO) has been investigated. The highest activity in the process of reduction of NO with CO possesses the sample Ag + Pd/SiO2. It has been found that the sol-gel method for preparation of bimetallic catalysts allows the formation of various catalytic active centers (CAC) which leads to high activity in reaction of NO reduction. The presence of Ag2O and PdO in these CAC allows the elimination of NO. The process of this elimination includes reduction of NO with CO at temperatures up to 200 оC as well as direct decomposition of NO at higher temperatures. [ABSTRACT FROM AUTHOR]

Lately silver has become extremely important among alloying additives used to produce glassy materials with specific tailored properties. The aim of the study is to characterize bioactive glasses belonging to the CaO–SiO2–P2O5–Ag2O system by SEM and EDX methods, as well as biocomposites based on natural rubber containing those fillers. The focus is on the influence that silver oxide and the mechanism of its effect have upon the properties of glasses and biocomposites. The results show that silver particles serve as crystallization centers for apatite formation in sol–gel glasses what leads to a serious change in the morphology and size of crystals and consequently in glass microstructure. Particles in the form of plates have been identified. This is an indication of silver-stimulated crystalline structure. A relation between the hydroxylapatite plaque and the concentration of silver particles has been found. The influence of silver oxide is expressed in noticeable changes in the adsorption texture properties of the glasses. In the composites, the aggregation of the filler particles has been observed and their size increases in the presence of silver oxide. The hydroxylapatite formed as a stand-alone phase in the sol–gel glass and acting as a filler has the most important role in tailoring the composite characteristics. [ABSTRACT FROM AUTHOR]