Water-resistant Gypsum Compositions with Man-made Modifiers

The work has studied the structure and properties of gypsum compositions modified with the manmade modifier based on metallurgical dust and multi-walled carbon nanotubes. The results show that changing the structure of solid gypsum leads to the increase in bending and compressive strength by 70,5% and 138% correspondingly, the water resistance increasing and the softening factor reaching 0,85. Modifying gypsum composition with complex additive leads to the formation of amorphous structures based on calcium hydrosilicates on the surface of primary gypsum crystallohydrates that bond gypsum crystals and reduce the access of water

Имитационное компьютерное моделирование нестабильности наколенника, которое сопровождается дисплазией отростков бедренной кости

Створено динамічну модель пателофеморального суглоба. Проведено визначення кутових та лінійних переміщень наколінка, а також еквівалентних за Мізесом напружень в хрящі наколінка при згинанні колінного суглоба від 0° до 30° в нормі та при нестабільності наколінка, що супроводжується дисплазією виростків стегнової кістки тип А та В. Встановлено, що при нестабільності наколінка концентратори напружень розташовуються лише на латеральній фасетці незалежно від типу дисплазії. Тип дисплазії впливає на кутові та лінійні переміщення наколінка, а також розподіл еквівалентних за Мізесом напружень в хрящі наколінка в нормі та при нестабільності.Constructed a dynamic model of patelofemoral joint on human-based simulation computer model of a complex system of movement connected elastic and rigid bodies. Options patella biomechanical movement of bodies connected by joints defined by vector given angular velocity of rotation of the tibia. Patella speed depends on patellar spring-equivalents tension forces in connection, providing interaction force between the bodies of the simulation model. In this article, using of information technologies and application software a dynamic simulation model of patellofemoral joint is created. By calculation and theoretical determination of the angular, linear displacements of the patella, and the equivalent of von Mises stress in the patellar cartilage at knee flexion from 0° to 30° in normal and patellar instability, which is accompanied by trochlear dysplasia type A and B established that the concentrators at patellar instability are placed only on the lateral facet, regardless of the type of trochlear dysplasia. Type of dysplasia affects patellar displacement and distribution of von Mises equivalent stress in the patellar cartilage in normal and at instability. The adequacy of the results of the numerical experiment tested by convergence controlled parameters values of stresses in the zones of maximum gradient.В данной работе на современном уровне развития информационных технологий и прикладного программного обеспечения создана динамическая имитационная модель пателофеморального сустава. Проведено расчетно-теоретическое определение угловых, линейных смещений надколенника, а также эквивалентных за Мизесом напряжений в хряще надколенника при сгибании коленного сустава от 0° до 30° в норме и при нестабильности, что сопровождается дисплазией мыщелков бедра тип А и В. Установлено, что при нестабильности надколенника концентраторы напряжений размещаются только на латеральной фасетке независимо от типа дисплазии. Тип дисплазии влияет на смещение надколенника и распределение эквивалентных за Мизесом напряжений в хряще надколенника в норме и при нестабильности

Transgene-induced CCWGG methylation does not alter CG methylation patterning in human kidney cells

Several reports suggest that C(m)CWGG methylation tends not to co-exist with (m)CG methylation in human cells. We have asked whether or not methylation at CCWGG sites can influence CG methylation. DNA from cells expressing an M.EcoRII–GFP fusion was actively methylated at CCWGG sites. CG methylation as measured by R.HpaII/R.MspI ratios was unchanged in cells expressing the transgene. Cloned representatives of C(m)CWGG methylated DNA often contained, or were adjacent to an ALU repeat, suggesting that M.EcoRII-GFP actively methylated gene-rich R-band DNA. The transgenic methyltransferase applied C(m)CWGG methylation to a representative human promoter that was heavily methylated at CG dinucleotides (the SERPINB5 promoter) and to a representative promoter that was essentially unmethylated at CG dinucleotides (the APC promoter). In each case, the CG methylation pattern remained in its original state, unchanged by the presence of neighboring C(m)CWGG sites. Q-PCR measurements showed that RNA expression from the APC gene was not significantly altered by the presence of C(m)CWGG in its promoter. Kinetic studies suggested that an adjacent C(m)CWGG methylation site influences neither the maintenance nor the de novo methylation activities of purified human Dnmt1. We conclude that C(m)CWGG methylation does not exert a significant effect on CG methylation in human kidney cells

A study on mechanical properties and structure of anhydrite binder modified by ultra-dispersed siltstone

This research is devoted to modification of physical and mechanical properties and structure of a binder based on natural anhydrite. A sedimentary rock siltstone was added into the composition as a mineral ultrafine additive. The presence of aluminosilicate minerals proves that finely ground siltstone can be used as a mineral additive in the composition of the anhydrite binder, accelerating crystallization of gypsum new formations and densifying the structure of gypsum stone. For the first time, the effectiveness of using sodium and ammonium phosphates as hardening activators of an anhydrite binder was shown. Siltstone, added to the composition in the amount from 0 to 5%, lead to up to 40% increase in strength, which is due to the action of siltstone particles as “crystallization centers” and formation of crystalline hydrates of calcium sulfate dihydrate on their surface. Combined action of calcined siltstone and lime leads to a 45% increase in strength due to the additional compaction by new hydration products formed in the course of metakaolin and lime interaction. Microstructural analysis showed that samples with calcined siltstone and lime have a more dense and uniform structure with a lower porosity, compared to those with only natural siltstone. First published online 03 February 202

Bactericide, Immunomodulating, and Wound Healing Properties of Transgenic Kalanchoe pinnata Synergize with Antimicrobial Peptide Cecropin P1 In Vivo

Procedure of manufacturing K. pinnata water extracts containing cecropin P1 (CecP1) from the formerly described transgenic plants is established. It included incubation of leaves at +4°C for 7 days, mechanical homogenization of leaves using water as extraction solvent, and heating at +70°C for inactivating plant enzymes. Yield of CecP1 (after heating and sterilizing filtration) was 0.3% of total protein in the extract. The water extract of K. pinnata + CecP1 exhibits favorable effect on healing of wounds infected with S. aureus (equal to Cefazolin) and with a combination of S. aureus with P. aeruginosa (better than Cefazolin). Wild-type K. pinnata extract exhibited evident microbicide activity against S. aureus with P. aeruginosa but it was substantially strengthened in K. pinnata + CecP1 extract. K. pinnata extracts (both wild-type and transgenic) did not exhibit general toxicity and accelerated wound recovery. Due to immunomodulating activity, wild-type K. pinnata extract accelerated granulation of the wound bed and marginal epithelialization even better than K. pinnata + CecP1 extract. Immunomodulating and microbicide activity of K. pinnata synergizes with microbicide activity of CecP1 accelerating elimination of bacteria

Immunomodulating and Revascularizing Activity of Kalanchoe pinnata Synergize with Fungicide Activity of Biogenic Peptide Cecropin P1

© 2017 N. S. Zakharchenko et al. Previously transgenic Kalanchoe pinnata plants producing an antimicrobial peptide cecropin P1 (CecP1) have been reported. Now we report biological testing K. pinnata extracts containing CecP1 as a candidate drug for treatment of wounds infected with Candida albicans. The drug constitutes the whole juice from K. pinnata leaves (not ethanol extract) sterilized with nanofiltration. A microbicide activity of CecP1 against an animal fungal pathogen in vivo was demonstrated for the first time. However, a favorable therapeutic effect of the transgenic K. pinnata extract was attributed to a synergism between the fungicide activity of CecP1 and wound healing (antiscar), revascularizing, and immunomodulating effect of natural biologically active components of K. pinnata. A commercial fungicide preparation clotrimazole eliminated C. albicans cells within infected wounds in rats with efficiency comparable to CecP1-enriched K. pinnata extract. But in contrast to K. pinnata extract, clotrimazole did not exhibit neither wound healing activity nor remodeling of the scar matrix. Taken together, our results allow assumption that CecP1-enriched K. pinnata extracts should be considered as a candidate drug for treatment of dermatomycoses, wounds infected with fungi, and bedsores

Composite building materials based on nanomodified cement systems

ABSTRACT: Introduction. This research work investigates the combined influence of nano-sized silicon dioxide (nano-SiO2 ), carbon nanotubes and surfactants on the structural and technological characteristics of cement compositions. Materials and research methods. The paper reveals the findings of a study on the effects of various dispersion techniques of carbon nanotubes (CNT) in surfactants, such as mechanical dispersion, ultrasonic treatment, and a combined method. It considers the uniformity of CNT distribution within the plasticizer and within the cement system, along with their impacts on the physical and mechanical properties of cement stone and concrete. Differential thermal and electron microscopic analysis of aqueous dispersions of carbon nanotubes and hardened activated nanomodified cement stone was carried out. Results and discussion. It has been experimentally proven that mixing nanotubes in dry cement does not allow them to be evenly distributed throughout the volume of the mixture. When using carbon nanotubes, the maximum effect is achieved when they are introduced into aqueous dispersions of plasticizers. The percentage of plasticizer was 1%, CNT 0,1% per 1 liter of water. The most effective method of dispersing carbon nanotubes in a plasticizer is a combined one. The results obtained were used in the preparation of cement stone and concrete compositions. Conclusion. The results show that complex additives consisting of nano-SiO2 and aqueous dispersions of carbon nanotubes have a positive effect on the physical-mechanical and structural-technological properties of cement stone and concrete. Graphic dependencies are shown indicating the effectiveness of using complex additives in the production of cement composite

Formation of porous structures in production technology of construction materials based on building gypsum plaster

ABSTRACT: Introduction. This article presents the results of the research works on formation of building gypsum plaster porous structure with the use of recovered anhydrite raw materials and chemical additives, and describes a method for production of wall materials. The relevance of this paper is stipulated by the need to expand the range and increase the manufacture of heat-insulating and structural-heat-insulating products based on gypsum binders and local mineral raw materials, as well as the development of technologies to ensure the production of gypsum materials with improved performance. The authors proposed certain methods for forming the porous structure of building gypsum plaster and improving its performance in terms of porosity and thermal conductivity through the use of modified recovered raw materials and chemical additives of calcium chloride and sodium carbonate. Materials and methods. The study of the effect of modifying additives on the properties of the mixture was carried out using gypsum paste of normal consistency (NC = 55%). The preparation of samples and testing were performed according to the methods specified in the national standards with the use of porous additives of calcium carbonate, fluoroanhydrite and chemical additives for the rheological properties of the mixture, average density and strength of the samples, the patterns and mechanism of the processes of gypsum stone structure formation were established. Results. The application of fluoroanhydrite modified in the disintegrator with an equimolar amount of calcium carbonate leads to a decrease in the average density of the samples to 40% with evenly distributed pores. The analysis of the microstructure of heat-insulating material samples with a density of 550 kg/m3 showed that the average diameter of micropores is 0.45 mm, while the thermal conductivity of samples with complex chemical additives has the thermal conductivity coefficient of 0.25 W/m°C, which is 30% lower than the thermal conductivity of samples without complex additives. Conclusions. The results obtained create the basis for using recovery raw materials and domestic modifying additives as a pore-forming agent, which allow regulating the structure of gypsum stone in order to produce effective wall material