Hydrogel Nanocomposites with Silver Nanoparticles

Copolymer hydrogels based on acrylic monomers (primarily acrylamide and acrylonitrile) are synthesized and their physicochemical properties are investigated. Methods of incorporation of nanoparticles of gold and silver into hydrogel pores and methods of their stabilization using reagents of different nature are developed. Our studies showed pronounced bactericidal properties of the nanocomposites regarding gram-positive and gram-negative bacteria and, at the same time, their biocompatibility to stem cells

Thermal effects of carbonated hydroxyapatite modified by glycine and albumin

In this work calcium phosphate powders were obtained by precipitation method from simulated solutions of synovial fluid containing glycine and albumin. X-ray diffraction and IR spectroscopy determined that all samples are single-phase and are presented by carbonate containing hydroxyapatite (CHA). The thermograms of solid phases of CHA were obtained and analyzed; five stages of transformation in the temperature range of 25-1000°C were marked. It is shown that in this temperature range dehydration, decarboxylation and thermal degradation of amino acid and protein connected to the surface of solid phase occur. The tendency of temperature lowering of the decomposition of powders synthesized from a medium containing organic substances was determined. Results demonstrate a direct dependence between the concentration of the amino acid in a model solution and its content in the solid phase

Проепілептогенний ефект наночастинок срібла на моделі пентиленететразол-індукованого кіндлінгу

On the model of pentylenetetrazol (PTZ)-induced kindling in Wistar rats the net reduction of ED50 dosage of PTZ, which was able to induce clonic seizures in 50% of experimental animals caused by silver nanoparticles was established. This effect was more pronounced in postponed period of kindling and was followed by intensification of electrographic epileptiform manifestations. Silver argentum nanoparticles influence on chronic seizure activity was determined in conditions of chronic experiment. Authors concluded that argentum nanoparticles are responsible for seizure activity enhancening.На моделі пентиленететразол (ПТЗ)-індукованого кіндлінгу у щурів лінії Вістар показано зниження середньоефективної дози ПТЗ, що викликає клонічні судоми у 50 % щурів під впливом системного застосування наночастинок срібла. Даний ефект був більш вираженим у віддаленому періоді кіндлінгу й супроводжувався посиленням електрографічних епілептиформних проявів. За умов хронічного експерименту проводили досліди із визначення впливу наночастинок срібла на вираженість хронічної судомної активності. Автори висловлюють думку, що підсилення інтенсивності судомної активності відбувається завдяки придатності наночастинок срібла

Electrospinning of hydrogels for biomedical applications

The field of biomedical applications for hydrogels requires the development of nanostructures with specific controlled diameter and mechanical properties. Nanofibers are ideally candidates for these advanced requirements, and one of the easiest techniques that can produce one-dimensional nanostructured materials in fibrous form is the electrospinning. This technique provides extremely thin fibres with controlled diameter, highly porous microstructure with interconnected pores; extremely versatile allowing the use of various polymers for tailoring various applications requirements and it is a simple cost-effective method on preparation of scaffolds. In this section, we will discuss recent and specific applications with a focus on their mechanisms. As such, we conclude this section with a discussion on perspectives and future possibilities on this field.ye

Composite Binders for Fastening High Temperature Wells

Abstract The article deals with the hydration of oil-well cement, intended for cementing high-temperature wells. At high temperatures and pressures (150°C, P = 30 MPa) Portland cement stone does not have the necessary density and resistance to high temperatures due to the formation of hydrated calcium silicates rich in lime during the hydration of Portland cement, therefore, the work was carried out primarily to find appropriate additives to Portland cement, providing the necessary properties of oil-well cement. From a number of additives to ensure the durability of service were selected reprocessing waste of titanium ores (titanomagnetite concentrate) and blast furnace slag. In addition, to improve the crack resistance of cement stone, the possibility of using expansive additives to oil-well cement was investigated. For these purposes, sulfoaluminate, sulfoferrite clinkers and alumina slag were used. It has been established that during hydration of calcium sulfoferrite ferrous ettringite is formed, which is more stable at elevated temperatures than ettringite formed at hydration of sulfoaluminate clinker and alumina slag. In the presence of sulfated phases and silica, at elevated temperatures and pressures, low-base calcium silicates hydrates and iron contained garnet hydrates are formed.</jats:p

Improving crack resistance of concrete when using expanding cements

Abstract The possibility of enhancing the basic properties of concrete products by using a mixture of Portland cement and sulfoalumoferrite clinker as a binder is considered. It was established that upon hydration of the binder, aluminate and ferruginous ettringite are formed, which increase the strength properties of concrete during normal hardening and thermal and wet processing by increasing the strengthening structure. The main sign of hydration of sulfoalumoferrite clinker is the stability of ferrous ettringite, which ensures the compaction of the concrete structure. The dense structure of the structure of concrete, especially the contact zone, when using sulfated clinker, ensures the non-shrinkage of concrete and eliminates shrinkage deformations and, thereby, increases the crack resistance of concrete samples.</jats:p

Synthesis of high alumina cement based on metallurgy wastes

Abstract In this paper efficient types of binders – high alumina cements are considered. The shortage of industrial alumina and its high cost constrain the development of high-aluminate cements production. Waste from a number of metallurgical industries can be used as raw materials for their production. The aim of the investigation was to study the influence of metallurgical waste on the mineral formation of aluminate clinker and the properties of cement based on it. As a replacement of industrial alumina, dust of gas cleaning plants of aluminum electrolysis and slag of ferroalloys production were used. Aluminate clinkers were obtained in a laboratory furnace at a temperature of 1200-14000 °C. Mineral composition of clinkers was studied using chemical analysis, XRD and optical microscopy. The cements were obtained by grinding clinkers in a laboratory mill, then they tested for strength at the age of 28 days. It was established that the chemical and phase composition of dust allows to use it as a raw component in the production of high alumina cement. The investigations showed that the properties of alumina cement based on slag ferrovanadium production improved. Hydration activity of cement increases especially in the early period of its hydration.</jats:p