Interactive toxicity effect of combined exposure to hematite and amorphous silicon dioxide nanoparticles in human A549 cell line

The study on the health effects of combined exposure to various contaminants has been recommended by many authors. The objective of the present study was to examine the effects of the co-exposure to hematite and amorphous silicon dioxide (A-SiO2) nanoparticles on the human lung A549 cell line. The A549 cell line was exposed to 10, 50, 100, and 250 µg/ml concentrations of hematite and A-SiO2 nanoparticles both independently and in combination. Their toxicity in both circumstances was investigated by MTT, intracellular reactive oxygen species, cell glutathione content, and mitochondrial membrane potential tests, and the type of interaction was investigated by statistical analysis using Statistical Package for Social Sciences (SPSS, v. 21). Results showed that the independent exposure to either hematite or A-SiO2 compared with the control group produced more toxic effects on the A549 cell line. The toxicity of combined exposure of the nanoparticles was lower compared with independent exposure, and antagonistic interactive effects were detected. The findings of this study could be useful in clarifying the present debate on the health effects of combined exposure of hematite and A-SiO2 nanoparticles. Because of the complexities of combined exposures, further studies of this kind are recommended.

Characterisation of Phytolith Production and Their Taxonomic Use among Five Species of Aristida

Phytoliths are amorphous silicon dioxide depositions in and around the cells of certain plants. Phytoliths of Poaceae are of great importance in the field of taxonomy and Archeology. Present study confirms the use of phytolith characters in the delimitation of Aristida species. Five species of Aristida were included in the study. Various characters like presence or absence of prickle hairs, nature of margins in lobate phytoliths, shank length in relation to the length of lobes etc. proved to be promising characters in the delimitation of the taxa. A taxonomic key to the identification of species is also provided.

High-throughput injection molding of transparent fused silica glass

Glass is one of the most relevant high-performance materials that has the benefit of a favorable environmental footprint compared with that of other commodity materials. Despite the advantageous properties of glasses, polymers are often favored because they can be processed using scalable industrial replication techniques like injection molding (IM). Glasses are generally processed through melting, which is both energy intensive and technologically challenging. We present a process for glassworks using high-throughput IM of an amorphous silicon dioxide nanocomposite that combines established process technologies and low-energy sintering. We produce highly transparent glass using classical IM and sintering, allowing for a potentially substantial reduction in energy consumption. Our strategy merges polymer and glass processing, with substantial implications for glass utilization.

THE ACID-BASE PROPERTIES OF AMORPHOUS SILICA FROM STRAW AND RICE HUSK

The present work shows results of studying acid-base properties of the surface by the methods of pH-metry and Hammett of amorphous silicon dioxide from rice husks and straw obtained by various schemes: oxidative firing; oxidative roasting with preliminary treatment with 0.1 M hydrochloric acid solution; precipitation from alkaline solutions. The samples obtained by the thermal method contain impurities of alkali, alkaline earth metals, aluminum, and aluminum and practically do not contain water. The composition of the deposited samples contains a small fraction of impurities (0.05%) and water - from 8.2 to 10.2%. The pH value of an aqueous suspension of silicon dioxide has a neutral, alkaline or acidic environment depending on the content of impurities of alkali and alkaline earth metals. Distribution of acid-base centers on the surface of the samples is nonmonotonic and heterogeneous, and manifests itself in discreteness with a fairly clear differentiation of sorption bands with maxima of different intensities corresponding to a certain pKa value. Distribution curves of the adsorption centers of the indicators on the surface of the samples of amorphous silicon dioxide are similar to each other. There are four types of active centers on their surface: acidic Lewis (pKa + 16.80), Bransted main (pKa +7.15 and +9.45) and acid (pKa + 2.50). The number of active centers depends on the preparation scheme and is determined by the content of impurity elements and water in the oxide samples.

Control of Ecotoxicants Content in Feed Additives and Veterinary Pharmacological Products

The article is devoted to the control of ecotoxicants content in mineral and organic substances of natural and artificial origin used in the production of feed additives and pharmacological veterinary agents. In the context of the growing technogenic load on the environment, the probability of detecting increased background levels of natural and technogenic ecotoxicants in mineral and organic raw materials for the production of feed additives and veterinary products increases significantly. In this regard, more attention should be paid to the study of substances of artificial origin with a minimum content of toxic and ballast components, as well as substances that have undergone technological processing to reduce their natural level of ecotoxicants. According to modern data, amorphous silicon dioxide is an effective, safe, economically available sorbing agent and it should be considered as a promising sorption-detoxifying agent for application under the influence of xenobiotics that differ in the toxicological action mechanism on the animal organism.

РАЗРАБОТКА ТЕХНОЛОГИИ ПОЛУЧЕНИЯ ФОСФОРНОГО КОМБИНИРОВАННОГО УДОБРЕНИЯ ИЗ БИОГЕННЫХ ДИАТОМИТОВЫХ ПОРОД АРМЕНИИ И ИССЛЕДОВАНИЕ ЕГО ЭФФЕКТИВНОСТИ

There are limited raw material resources (apatites) for manufacturing phosphorus fertilizers. The studies have disclosed that the phosphorus fertilizers can be also produced from the phosphorus-containing biogenic diatomite rocks widely spread in Armenia. A technology of manufacturing a complex phosphorus fertilizer (phosphorus + iron + amorphous silicon dioxide) from the mentioned rocks has been developed. According to the results of trials on maize and spring barley the recommended fertilizer exceeds the superphosphates in its efficiency; anyhow, the technology of fabricating the discussed fertilizer still needs to be improved.