Vladimir V. Chaika

Size-segregated emissions and metal content of vehicle-emitted particles as a function of mileage: Implications to population exposure.

The study aims at investigating the characteristics (size distribution, active surface and metal content) of particles emitted by cars as a function of mileage using a novel methodology for characterizing particulate emissions captured by Exhaust Gas Suspension (EGS). EGS was obtained by passing the exhaust gases through a container of deionized water. EGS analysis was performed using laser granulometry, electron scanning microscopy, and high resolution mass spectrometry. Implications of the differences in key features of the emitted particles on population exposure were investigated using numerical simulation for estimating size-segregated PM deposition across human respiratory tract (HRT). It was found that vehicle mileage, age and the respective emissions class have almost no effect on the size distribution of the exhaust gas particulate released into the environment; about half of the examined vehicles with low mileage were found to release particles of aerodynamic diameter above 10 μm. The exhaust gas particulate detected in the EGS of all cars can be classified into three major size classes: (1) 0.1-5 µm - soot and ash particles, metals (Au, Pt, Pd, Ir); (2) 10-30 µm - metal (Cr, Fe, Cu, Zr, Ni) and ash particles; (3) 400-1,000 µm - metal (Fe, Cr, Pb) and ash particles. Newer vehicles with low mileage are substantial sources of soot and metal particles with median diameter of 200 nm with a higher surface area (up to 89,871.16 cm(2)/cm(3)). These tend to deposit in the lower part of the human respiratory tract.

Basophil mediated pro-allergic inflammation in vehicle-emitted particles exposure.

Abstract Despite of the fact that engine manufacturers develop a new technology to reduce exhaust emissions, insufficient attention given to particulate emissions. However, diesel exhaust particles are a major source of air‐borne pollution, contain vast amount of polycyclic aromatic hydrocarbons (PAHs) and may have deleterious effects on the immune system, resulting in the induction and enhancement of pro‐allergic processes. In the current study, vehicle emitted particles (VEP) from 2 different types of cars (diesel ‐ D and gasoline ‐ G) and locomotive (L) were collected. Overall, 129 four‐week‐old, male SPF‐class Kunming mice were subcutaneously instilled with either low dose 100, 250 or high dose, 500 mg/kg VEP and 15 mice were assigned as control group. The systemic toxicity was evaluated and alterations in the percentages of the CD3, CD4, CD8, CD16, CD25 expressing cells, basophils, eosinophils and neutrophils were determined. Basophil percentages were inversely associated with the PAH content of the VEPs, however basophil sensitization was more important than cell count in VEP exposure. Thus, the effects of VEP‐PAHs emerge with the activation of basophils in an allergen independent fashion. Despite the increased percentage of CD4+ T cells, a sharp decrease in basophil counts at 500 mg/kg of VEP indicates a decreased inhibitory effect of CD16+ monocytes on the proliferation of CD4+ T cell and suppressed polarization into a Th2 phenotype. Therefore, although the restrictions for vehicles emissions differ between countries, follow up studies and strict regulations are needed. HighlightsBasophil sensitization is more important than cell count in VEP exposure.CD16+ cells are more effective than basophils on CD4+ T cell proliferation.CD16+ and CD16‐ monocytes respond to VEP exposure in opposite directions.CD8+ T cell proliferation is inhibited by all doses of VEPs.Globally, more stringent standards are needed for vehicle particle emissions.

Influence of multi-walled carbon nanotubes on the cognitive abilities of Wistar rats

Studies of the neurobehavioral effects of carbon nanomaterials, particularly those of multi-walled carbon nanotubes (MWCNTs), have concentrated on cognitive effects, but data are scarce. The aim of this study was to assess the influence of MWCNTs on a number of higher nervous system functions of Wistar rats. For a period of 10 days, two experimental groups were fed with MWCNTs of different diameters (MWCNT-1 group, 8–10 nm; MWCNT-2 group, 18–20 nm) once a day at a dosage of 500 mg/kg. In the open-field test, reductions of integral indications of researching activity were observed for the two MWCNT-treated groups, with a parallel significant (P<0.01) increase in stress levels for these groups compared with the untreated control group. In the elevated plus-maze test, integral indices of researching activity in the MWCNT-1 and MWCNT-2 groups reduced by day 10 by 51 and 62%, respectively, while rat stress levels remained relatively unchanged. In the universal problem solving box test, reductions in motivation and energy indices of researching activity were observed in the two experimental groups. Searching activity in the MWCNT-1 group by day 3 was reduced by 50% (P<0.01) and in the MWCNT-2 group the relevant reduction reached 11.2%. By day 10, the reduction compared with controls, was 64% (P<0.01) and 58% (P<0.01) for the MWCNT-1 and MWCNT-2 groups, respectively. In conclusion, a series of specific tests demonstrated that MWCNT-treated rats experienced a significant reduction of some of their cognitive abilities, a disturbing and worrying finding, taking into consideration the continuing and accelerating use of carbon nanotubes in medicine and science.

Study of the influence of multiwalled carbon nanotubes (12–14 nm) on the main target tissues of the bivalve Modiolus modiolus

The reaction of bivalves Modiolus modiolus to pulse (for 24 and 48 h) exposure with multiwalled carbon nanotubes (MWCNTs) (12–14 nm, MWNT concentration in sea water of 100 mg/L) is manifested in the ingestion of MWCNT aggregates formed in seawater despite their rapid sedimentation from the water column to the bottom of the aquariums. After 24 h, the MWCNT aggregates are observed in the intestinal lumen (size of 10 to 150 μm) and in the tubules of the digestive gland (10 to 50 μm). After 48 h, only large aggregates in contact with mucus and desquamated epithelium fragments are detected in the lumen of the intestine. The smallest aggregates seem to be inside epithelial cells. In the intestine, digestive gland, and gills, MWCNT aggregates induce histopathological changes in the epithelium (erosion, necrosis, trend towards increased vacuolization of the cells) and swelling of the connective tissue. In the gill epithelium after 48 h, patterns morphologically corresponding to apoptosis are observed. Despite significant organ damage, no change in the cellular composition of the hemolymph in mussels exposed to the MWCNTs is found.

Phytoliths in Taxonomy of Phylogenetic Domains of Plants

We discuss, from the aspect of phylogeny, the interrelationships of the phytolith types in plants from the main taxonomical groups (algae, lichens, horsetails, gymnosperms, and floral plants) with homologues of known proteins of biomineralization. Phytolith morphotypes in various phylogenetic plant domains have different shapes. We found that, in ancient types of plants (algae, horsetails, and gymnosperms), there are fewer different phytolith morphotypes compared to more modern plants (floral plants). The phytolith morphotypes in primitive plants are generally larger than the morphotypes in more highly organized plants. We found that the irregular ruminate and irregular smooth morphotypes are the two most frequently encountered phytolith morphotypes in the tested plants (from algae to floral plants). These two morphotypes probably have a universal role. Silacidins, silicon transporters, silicateins, silaffins, and silicase homologues are often found in the major taxonomic groups of plants. Red algae had the smallest number of homologues of the biomineralization proteins (70–80), Monocotyledonous: 142, Coniferous: 166, Mosses: 227, and Dicotyledones: 336.

Short-Time Effect of Multi-Walled Carbon Nanotubes on Some Histological and Biochemical Parameters in Marine Bivalves Crenomytilus grayanus (Dunker, 1853) and Swiftopecten swifti (Bernardi, 1858)

The marine bivalves, mussels Crenomytilus grayanus (Dunker, 1853) and scallops Swiftopecten swifti (Bernardi, 1858), were in vivo exposed to 12-14 nm multi-walled carbon nanotubes (MWNTs) for up to 48 h. Microscopic analysis in combination with the RAMAN spectrophotometry revealed the MWNT aggregates on the gills surface and inside the gut of all exposed individuals. After 48 h exposure, there were no changes in the total cell count, the average cell size and granularity in the hemolymph of mussels, while in the scallops the total hemocyte count was significantly reduced, and the average hemocyte granularity increased. Biochemical markers of oxidative stress (activity of glutathione-S-transferase and catalase, concentration of reduced glutathione, and the degree of lipid peroxidation) did not change significantly in the digestive gland of both mussels and scallops. In hemolymph, catalase activity increased as compared to control in both mussels and scallops. Moreover, concentration of reduced glutathione increased in hemolymph of scallops on the second day of exposure to MWNTs. The data obtained indicate that MWNTs may affect different bivalve mollusks more or less strongly under the same exposure conditions.

Effects of carbon and silicon nanotubes and carbon nanofibers on marine microalgae Heterosigma akashiwo

ABSTRACT The effect of carbon and silicon nanotubes (CNTs and SiNTs) and carbon nanofibers (CNFs) to microscopic marine algae Heterosigma akashiwo was studied, using algal growth inhibition for 3 days (acute effect) and 7 days (chronic effect) as toxicity endpoints. The criterion of the toxic effect was the statistically significant reduction of the number of algal cells in the exposed samples compared to the control. Samples did not demonstrate toxic effects at doses 1 mg/l and 10 mg/l. CNTs and SiNTs samples at 100 mg/l exhibited both acute and chronic toxic effects. We assume that the main cause of cell death in these samples was related to the mechanical damage of cell integrity. CNFs at concentrations of 100 mg/l did not inhibit algal growth, but cells with irregular shapes were observed, which were not observed after exposure to CNTs and SiNTs. Nickel impurities present in CNFs samples are presumably the main cause of observed cell deformations. Graphical abstract: Figure. No caption available. HighlightsCarbon and silicon nanotubes did not inhibit algal growth up to 10 mg/l.Carbon nanofibers did not inhibit algal growth at 100 mg/l.Cell death of marine alga Heterosigma akashiwo was associated with mechanical damage.Nickel impurities in carbon nanofibers caused irregular shape formation.

3D-Modeling of the Distribution of Welding Aerosol Nano- and Microparticles in the Working Area

The first results of the research of the distribution of welding aerosol nano- and microparticles in the working area based on substance and morphological analysis are presented in the paper. A 3D-model of the welding aerosol cloud demonstrating the distribution of nano- and microparticles in the working area of the welder was created using the granulometric data of the samples. The most dangerous area with maximum density of nano- and microparticles of welding fumes was singled out: 1.3 m in height and 5 meters in all directions.Welding aerosol is a disperse system in which the solid component of the welding aerosol (SCWA) acts as the phase, and the mixture of gases (gaseous component of welding aerosol, or GCWA) – as the medium. SCWA stays suspended in the air for a long time spreading far beyond the working area of a welder [1].The aim of this work was to create a 3D-model of a welding aerosol cloud, demonstrating the spread of nano- and microparticles of welding aerosol in the working area of a welder. The 3D model was created using granulometric data of samples collected by the author’s method.

Oral application of carbon nanofibers in rats increases blood concentration of IL6 and IL10 and decreases locomotor activity

Carbon nanofibers (CNF) are versatile nanomaterials that are widely used in various fields of science and technology. As a consequence, animals as well as humans may be exposed to such compounds via different routes. We hypothesized that oral intake of CNF will lead to an inflammatory reaction and consequently induce behavioral impairments. To address this issue, rats were fed with 500mg/kgCNF for 14days and their locomotor activity, emotional status and cognition were quantified by testing the animals in an open field set-up, elevated plus maze and in the universal problem solving box which provides information about motivation and cognition. The behavioral tests were performed 3 times within 10days. At the end of the experiment, blood samples were collected and the plasma concentrations of IL-6, IL-8, IL-1β, IL-10 and IL-18 were measured. Our results demonstrated an inflammatory reaction determined by a significantly elevated IL-6 concentration. This, however, was counteracted by an even more pronounced increase in IL-10. The behavioral effects were restricted mainly to a decrease in locomotor activity which was significant in the open field test, as well as the elevated plus maze. Other parameters indicative of cognitive performance were not influenced and also the emotional status was largely unaffected. In conclusion, our results revealed that oral intake of 500mg/kgCNF induced some adverse effects, which, however, can be still partially compensated by the organism.

Granulometry of atmospheric suspension of Zeysky State Reserve (Amur region, Russian Federation)

The paper presents the results of granulometry studying of particles of atmospheric suspension contained in snow samples collected in Zeya state reserve (seasons winter 2013/2014 years). Snow samples collected at 5 stations were revealed to contain the particles the size of less than 10 μm in ecologically insignificant concentrations (up to 4%). Generally, the particles of 3rd (10-50 μm) and 6th (400-700 μm) size classes prevail at all sampling stations. The particles at all sampling stations have relatively small specific surface area - from 401, 87 to 4720, 22 сm2/сm3. It is possible to draw an inference that from the point of view of micro size pollution of atmosphere Zeya state reserve is considered to be a territory with farourable conditions.