Sergey B. Venig

GLOBULAR GRAPHITE: STRUCTURE, COMPOSITION

The structure and elemental composition of graphite inclusions uncovered on high-strength cast iron by etching are studied. The chemical composition at various points and regions of graphite inclusions is determined. It is shown that the globular graphite is a unique lamellar-spiral system of micro- and nanoformations.

A new x-ray adhesive system with embedded nanoparticulate silver markers for dental applications

In the present study a new adhesive system with embedded PVP-stabilized nano-particulate silver markers has been designed. Nanosized silver was used as a radio-opaque contrast material in SEM examination of adhesive system in dentine. It was studied the impact of nano-particulate silver fillers on rheological properties of adhesive system and its penetration in dentine volume. A SEM comparative evaluation of resin replicas produced using adhesive system with embedded silver nanoparticles and that without ones was carried out. It was shown that embedding of silver nanoparticles into adhesive system did not make its penetration worse. It was established that embedding of nanosized silver changed adhesive system morphology. The methodology that allows visualizing interfaces and intermediate layers between dentine, adhesive system and restorative material using silver nano-particulate markers was developed and approved. Silver nanoparticles were used to compare the objective depth of penetration of adhesive systems of different generations in root dentine with differently oriented dentinal tubules, bonding resin delivery and gravity.

Antibacterial Composites Based on a Natural Sorbent

The paper presents an investigation of the antibacterial activity of composites that are obtained based on a natural sorbent with immobilized antibiotics, tetracycline, and doxycycline. Both the investigated composites effectively inhibited Staphylococcus aureus, but were not effective against Escherichia coli. The paper also presents the results of an investigation of the elemental composition and some characteristics of the porous surface of the glauconite sorbent of the Beloozero field in Saratov oblast.

Determination of the sorption characteristics of glauconite during extraction of a pharmaceutical from an aqueous medium

A technique for preparing enriched glauconite on the basis of a natural mineral from the Beloozyorskoe field of Saratov oblast has been developed. The results of a study of the chemical composition, surface structure, and certain physicochemical properties of the samples of the sorbent are presented. The sorption of ambroxol hydrochloride ions from aqueous solutions has been studied using natural and enriched glauconite. The sorption isotherms, are approximated by the Langmuir equation, have been obtained, and the values of the maximum sorptive capacities have been calculated. Based on the obtained data, conclusions have been drawn on using the studied natural mineral sorbents to extract the above-mentioned substance from aqueous solutions.

Synthesis of glauconite composites and study of their antibacterial activity

The elemental composition, the surface morphology and the sorption properties of glauconite from the Beloozerskoye deposit in Saratov Region were investigated. The nanocomposites based on glauconite as a matrix with doxycycline and tetracycline were synthesised. The antibacterial activity of the obtained composites against Staphylococcus aureus was studies.

Effect of thermal shock loadings on stability of dentin-composite polymer material adhesive interfaces

In the past several decades the problem of longevity and durability of adhesive interfaces between hard tooth tissues and composite resin-based materials are of great interest among dental researchers and clinicians. These parameters are partially determined by adhesive system mechanical properties. In the present research project nanoindentation has been examined to test hardness of dental adhesive systems. A series of laboratory experiments was performed to study the effect of light curing time and oxygen inhibition phenomenon on light-cured adhesive material hardness. An adhesive system AdperTM Single Bond (3M ESPE) was selected as a material for testing. The analysis of experimental data revealed that the maximum values of hardness were observed after the material had been light-cured for 20 seconds, as outlined in guidelines for polymerization time of the adhesive system. The experimental studies of oxygen inhibition influence on adhesive system hardness pointed out to the fact that the dispersive layer removal led to increase in adhesive system hardness. A long – time exposure of polymerized material of adhesive system at open air at room temperature resulted in no changes in its hardness, which was likely to be determined by the mutual effect of rival processes of air oxygen inhibition and directed light curing.

Application of color image processing and low-coherent optical computer tomography in evaluation of adhesive interfaces of dental restorations

Durability of bonded interfaces between dentin and a polymer material in resin-based composite restorations remains a clinical dentistry challenge. In the present study the evolution of bonded interfaces in biological active environment is estimated in vivo. A novel in vivo method of visual diagnostics that involves digital processing of color images of composite restorations and allows the evaluation of adhesive interface quality over time, has been developed and tested on a group of volunteers. However, the application of the method is limited to the analysis of superficial adhesive interfaces. Low-coherent optical computer tomography (OCT) has been tested as a powerful non-invasive tool for in vivo, in situ clinical diagnostics of adhesive interfaces over time. In the long-term perspective adhesive interface monitoring using standard methods of clinical diagnostics along with colour image analysis and OCT could make it possible to objectivise and prognosticate the clinical longevity of composite resin-based restorations with adhesive interfaces.

Mechanical properties of adhesive system with a silver nanoparticulate filler: an experimental study

In the present study nanoparticulate silver filler influence on adhesive system mechanical properties has been researched. In the course of laboratory experiments it has been shown that adhesive system mechanical properties are changing in a different manner as soon as silver percentage in adhesive system is increasing. It has been established that 0,5 –1% silver nanoparticle embedding into adhesive system that is enough to make the material X-Ray-sensitive holds its mechanical properties close to the optimum. Thus, the mechanical properties are enhancing in comparison with those of adhesive system without silver nanoparticles. Research findings point to the opportunity to use nanoparticulate silver as a filler while producing X-ray adhesive systems.

SEM Evaluation of Nanoparticulate Silver Penetration into Dentine Collagen Matrix

In the present study a novel approach to caries management based on the application of nanoparticles of different nature to increase the mineral phase of demineralized dentin has been developed. Silver nanoparticles have been tested as a material for dentine matrix infiltration. Research findings clearly show that collagen fibers of demineralized dentine could be considered as a scaffold for mineral component delivery and the place where mineral growth can occur.

The formation of quality management competences in engineering education

The last decade there is discussion about methods and means of improving quality of engineering education and about ways to implement them in a high school practice. The authors focus on the question of forming competences in the field of quality management on the example of educational direction “Materials Science and Technology of Materials”. As shown the producing departments often include in the engineering curriculum core subjects for this department. At the same time some of the professional competences (e.g. quality management competences) are given in a summary and general form. By considering a great importance of quality management skills for engineering graduate nowadays, it is stressed necessity of including practice-oriented disciplines, partition of disciplines and practices, that form related competences, in the curriculum of bachelors and masters of engineering. The authors also give some examples for acquisition the quality management competence within special sections of professional disciplines and practices.