Effect of an internal Kelvin wave on sound propagation in a coastal wedgea).

Spatiotemporal variability of the low-frequency sound field in a coastal wedge in the presence of an internal Kelvin wave (IKW) is studied both experimentally and theoretically. The experiments were carried out in Lake Kinneret, Israel (also known as the Sea of Galilee) in August 2021, with a wideband sound source deployed near the shore and receiving vertical line arrays located at the lake's center. Parameters of the IKW were obtained earlier from long-term thermistor string measurements combined with conductivity, temperature, and depth data. The IKW initiated range-dependent vertical displacements of the thermocline with a maximum amplitude near the shore and almost zero amplitude in the center of the lake. It corresponded to a thermocline inclination angle of ±0.08° with respect to the horizontal. Temporal variations in depth-averaged acoustic intensity, reaching almost 8 dB, and remarkable changes in the normal mode composition were registered. These effects are explained based on simulations using a parabolic equation and normal mode models. The role of mode coupling in acoustic intensity variations is assessed.

Changes in the Dose-Response Relationship of One Toxicant Under Simultaneous Exposure to Another Toxicant.

We considered, in general form for a 22 full factorial experiment, linear approximations of the organism's dose-response relationship for some factors operating alone and modification of this relationship by another factor operating in the background. A typological classification of such modifications is suggested. An analysis of the outcomes obtained in a number of subchronic animal experiments on rats in which this response was assessed by changes in a large number of biomedical indices revealed that all theoretically possible variants (types) of the modification under consideration are actually observed depending on a specific index and specific harmful exposure. Statistical significance estimation procedures are formulated for each of them.

On the contribution of the phagocytosis and the solubilization to the iron oxide nanoparticles retention in and elimination from lungs under long-term inhalation exposure.

The aim of our study was to test a hypothesis according to which the pulmonary clearance vs. retention of metal oxide nanoparticles (NPs) is controlled not only by physiological mechanisms but also by their solubilization which in some cases may even prevail. Airborne Fe2O3 NPs with the mean diameter of 14±4nm produced by sparking from 99.99% pure iron rods were fed into a nose-only exposure tower. Rats were exposed to these NPs for 4h a day, 5days a week during 3, 6 or 10 months at the mean concentration of 1.14±0.01mg/m(3). NPs collected from the air exhausted from the exposure tower proved insoluble in water but dissolved markedly in the cell free broncho-alveolar lavage fluid supernatant and in the sterile bovine blood serum. The Fe2O3 content of the lungs and lung-associated lymph nodes was measured by the Electron Paramagnetic Resonance (EPR) spectroscopy. We found a relatively low but significant pulmonary accumulation of Fe2O3, gradually increasing with time. Besides, we obtained TEM-images of nanoparticles within alveolocytes and the myelin sheaths of brain fibers associated with ultrastructural damage. We have developed a multicompartmental system model describing the toxicokinetics of inhaled nanoparticles after their deposition in the lower airways as a process controlled by their (a) high ability to penetrate through the alveolar membrane; (b) active endocytosis; (c) in vivo dissolution. To conclude, both experimental data and the identification of the system model confirmed our initial hypothesis and demonstrated that, as concerns iron oxide NPs of the dimensions used, the dissolution-depending mechanisms proved to be dominant.

Applying theoretical premises of binary toxicity mathematical modeling to combined impacts of chemical plus physical agents (A case study of moderate subchronic exposures to fluoride and static magnetic field).

Sodium fluoride solution was injected i.p. to rats at a dose equivalent to 0.1 LD50 three times a week up to 18 injections. Two thirds of these rats and of the sham-injected ones were exposed to the whole body impact of a 25 mT static magnetic field for 2 or 4 h a day, 5 times a week. For mathematical analysis of the effects they produced in combination, we used a response surface model. This analysis demonstrated that (like in combined toxicity) the combined adverse action of a chemical plus a physical agent was characterized by a diversity of types depending not only on particular effects these types were assessed for but on their level as well. From this point of view, the indices for which at least one statistically significant effect was observed could be classified as identifying (1) single-factor action; (2) additivity; (3) synergism; (4) antagonism (both subadditive unidirectional action and all variants of contradirectional action). Although the classes (2) and (3) taken together encompass a smaller part of the indices, the biological importance of some of them renders the combination of agents studied as posing a higher health risk than that associated with each them acting alone.

[APPROACHES TO ENHANCING THE ORGANISM'S RESISTANCE TO THE ADVERSE EFFECTS OF NANOMATERIALS AS EXAMPLIFIED BY NANOSILVER AND NANOCOPPER OXIDE].

Subchronic intoxications in rats induced by repeated intraperitoneal injections of stable water suspensions of silver or copper oxide nanoparticles in low dosage were manifested by adverse shifts in some functional and biochemical indices, by development of histo-structural changes in different tissues and by poly-organ fragmentation of DNA. All these manifestations of toxicity were substantially attenuated against the background of parallel oral administration of bioprotective complexes comprising vitamins, trace elements, pectin, some amino acids and a fish oil preparation rich in omega-3 fee fatty acids, this composition has been adjusted to mechanisms of action of this or that nanomaterial.

Interaction of iron oxide Fe3O4 nanoparticles and alveolar macrophages in vivo.

Aqueous suspension of magnetite nanoparticles with primary diameter of 10 nm were intratracheally administered into rat lungs. In 24 h, cells were isolated from bronchoalveolar lavage and examined under a transmission electron microscope. Alveolar macrophages demonstrated ability to actively uptake single nanoparticles and small aggregates composed of such particles, which then formed larger conglomerates inside fused phagosomes. Some of these mature phagosomes shed the membrane and free nanoparticles closely interacted with nuclear membrane and with cristae and mitochondrial membranes thereby inflicting pronounced damage to these intracellular structures. The loss of primary lysosomes can be viewed as indirect evidence attesting to the role played by diffusion of lysosomal hydrolytic enzymes in the final destruction of the alveolar macrophages provoked by nanoparticles.

Combined subchronic fluoride-lead intoxication and its attenuation with the help of a complex of bioprotectors.

BACKGROUND: Combined toxicity of lead and fluoride has been studied insufficiently, and there is no known information about attempts to inhibit it with any bioprotectors. METHODS: Lead acetate and sodium fluoride, administered separately or in combination, were injected i.p. to rats at isoeffective sublethal doses 3 times a week for 6 weeks. Some of the rats were exposed to the same combination against the background of oral administration of a bioprotector complex (BPC) comprising pectin, glutamate, and multivitamin/multimineral preparations. Following exposure, functional and biochemical indices and histopathological examinations of the femur of exposed and control rats were evaluated for signs of toxicity. RESULTS: We have shown that with regard to a number of effects on the organism level the combined toxicity of lead and fluoride may be evaluated as additive or even superadditive, but lead reduces fluoride accumulation in the bone, and pathological changes in the bone tissue proved to be less marked for combined exposure compared with separate exposures. The BPC has been demonstrated to attenuate a range of the combined harmful effects of lead and fluoride, including those on the bone tissue. CONCLUSIONS: In spite of the fact that fluoride and lead may reciprocally attenuate their harmful effects on the bone tissue in case of combined exposure, they prove to be more toxic for soft tissues just in combination than when administered separately. The development of combined intoxication may be substantially inhibited by means of the tested set of innocuous biologically active agents.

Toxicity of monazite particulates and its attenuation with a complex of bio-protectors.

BACKGROUND: Workers employed on mining, processing and storage of monazite are at risk of exposure to dust with expected adverse health effects. OBJECTIVES: To study the adverse health effects of monazite particles in experiments on rats and to test the possibility of attenuating these effects. METHODS: Outbred white rats were injected intratracheally with a suspension of ground monazite concentrate (MC) in order to investigate the cellular response of the lower airways 24 hours later and the organism's status 6 months after the injection. The bio-protective complex (BPC) tested in these experiments consisted of glutamate, an iodine preparation, methionine, a polyvitamin-polymineral composition, and/or "Eicosavitol" (fish oil preparation rich in PUFA, predominantly of the omega 3-group). Bio-protectors were administered together with the rat food and drink daily for one month before the MC injection in the short-term experiment, or over 6 months after such injection in the long-term experiment. RESULTS: MC induced manifestations of its cytotoxicity, fibrogenicity and systemic toxicity as well as genotoxicity. The tested BPC attenuated virtually all these effects. Although a similar protective potential of "Eicosavitol" against almost all of them was lower compared with that of BPC, combining BPC with "Eicosavitol" provided, as a rule, the greatest protective effect. CONCLUSION: It may be assumed that the many-sided adverse effects of MC on the organism is due, at least partially, to the presence in its composition of not only rare earth elements but also of natural radioisotopes of the thorium and uranium families. The combination of the bio-protectors tested was highly effective and may be recommended for administering in periodic preventive programmes to exposed workers.

Observation of sound focusing and defocusing due to propagating nonlinear internal waves.

Fluctuations of the low frequency sound field in the presence of an internal solitary wave packet during the Shallow Water '06 experiment are analyzed. Acoustic, environmental, and on-board ship radar image data were collected simultaneously before, during, and after a strong internal solitary wave packet passed through the acoustic track. Preliminary analysis of the acoustic wave temporal intensity fluctuations agrees with previously observed phenomena and the existing theory of the horizontal refraction mechanism, which causes focusing and defocusing when the acoustic track is nearly parallel to the front of the internal waves [J. Acoust. Soc. Am., 122(2), pp. 747-760 (2007)].

Exposure to indoor mould and children's respiratory health in the PATY study.

BACKGROUND: Living in a damp or mouldy home reportedly damages children's respiratory health, yet mould appears not to be a prominent risk factor in the public's perception. Analyses of data on over 58,000 children from the Pollution and the Young (PATY) study are presented. In this collaboration, researchers from 12 cross-sectional studies pooled their data to assess the effects of air quality on a spectrum of children's respiratory disorders. METHOD: Original studies were conducted in Russia, North America and 10 countries in Eastern and Western Europe. Pooled analyses were restricted to children aged 6-12 years. Associations between visible mould reported in the household and a spectrum of eight respiratory and allergic symptoms were estimated within each study. Logistic regressions were used, controlling for individual risk factors and for study area. Heterogeneity between study-specific results and mean effects (allowing for heterogeneity) were estimated using meta-analysis. RESULTS: Visible mould was reported by 13.9% of respondents in Russia, increasing to 39.1% in North America. Positive associations between exposure to mould and children's respiratory health were seen with considerable consistency across studies and across outcomes. Confounder-adjusted combined ORs ranged from 1.30 (95% CI 1.22 to 1.39) for "nocturnal cough" to 1.50 (1.31 to 1.73) for "morning cough". Evidence of stronger effects in more crowded households was statistically significant for only asthma and sensitivity to inhaled allergens. No consistent interactions between mould and age, sex or parental smoking were found. CONCLUSION: Indoor mould exposure was consistently associated with adverse respiratory health outcomes in children living in these diverse countries.

Some considerations concerning multimedia-multipollutant risk assessment methodology: use of epidemiologic data for non-cancer risk assessment in Russia.

The highly industrialized small town of Verkhnyaya Pyshma (in the Urals region of Russia) was chosen as the site of a multimedia-multipollutant risk assessment using the U.S. Environmental Protection Agency methodology. The assessment was based on routine environmental pollution monitoring data for ambient air, soils, drinking water, and food, and the international environmental epidemiology literature. Using an a priori set of the preliminary health-based criteria, we selected nine pollutants for risk assessment: total suspended particles (TSP), sulfur dioxide, nitrogen dioxide, benzo(a)pyrene (BaP), ammonia arsenic, copper, cadmium, and lead. We used dose-response functions derived from epidemiologic studies to assess individual and population risks for TSP, SO2, NO2, As, Cd, and Pb. We assessed both cancer (for BaP, As, and Cd) and non-cancer (for all the chosen pollutants but BaP) responses, but in this paper we discuss only the assessments of noncarcinogenic risks due to TSP, SO2, NO2, Pb, and Cd as examples of how the quantitative estimates of health effects can be produced by using a risk function approach. We also schematically present a modified conceptual model of multimedia-multipollutant risk assessment taking into account the experience gained with this study.

Use of health information systems in the Russian federation in the assessment of environmental health effects.

The Russian Federation has made an intensive effort to compile and use information on the environment and human health. In 1996-1997, we evaluated the information that was collected and analyzed on the local (raion), regional (oblast), and federal levels with reference to its usefulness in the assessment of environmental health effects. The Russian Federation maintains standardized nationwide institutions that routinely collect health data in polyclinics and hospitals and then report to the national offices. The allocations of the workforce and the broad range of surveyed health outcomes are extensive, but a lack of systematic control of information quality limits the ability to take full advantage of these efforts. On the other hand, the hierarchical system of data collection has advantages over more decentralized or commercial health systems. A major weakness in the current reporting is the aggregation and transformation of data. Although this may not disturb the generation of health statistics, it seriously limits the use of regional and federal level data in the assessment of health effects of environmental exposures. In spite of limitations, some revised approaches to the analysis of existing data may be both feasible and fruitful. Combining information from routine data and newly collected data is likely to be the most effective way to assess the relationship between environmental exposures and diseases. Although there is a strong and justifiable desire to rapidly translate information of environmental health effects into policy alternatives, at present, it seems more useful to emphasize data quality, completeness, and plans for the use of data.

On the relationship between activation and breakdown of macrophages in the pathogenesis of silicosis (an overview).

Silica particles cause considerable damage to macrophages resulting in their eventual breakdown. At the same time, the development of silicosis involves a number of mechanisms associated with the activation of macrophages. In suggesting schemes for the pathogenesis of this disease many authors associate the central part with activation, completely neglecting damage to cells. Our experiments have shown, however, that much of the activation phenomena could be reproduced in vitro or in vivo by exposing macrophages to macrophage breakdown products. Alternatively, the secondary character of activation is demonstrated by the fact that it reveals itself only at silica doses which cause part of the cells to lose their viability in the same culture. Our data show that the range of macrophage activation phenomena which could be considered as secondary with respect to the breakdown of cells includes the production of neutrophil attractants, enhanced co-operation with T lymphocytes, increase in phagocytic activity, enhancement of cellular O2 consumption and peroxidation, an increase in the activity of dehydrogenases, reduction in the activity of 5'-nucleotidase, and some other effects. Although not denying that small silica doses may be able to exert a direct activating influence upon the macrophage we do, however, believe that the most important and primary role in the pathogenesis of silicosis is played by the damage to and the breakdown of this cell.

An approach to detecting delayed effects of radioactive contamination on industrial-urban-area dwellers.

Detecting changes in humans that result from radioactive contamination of the area of residence many years after an incident (i.e., when the radiation has substantially decayed) presents a difficult epidemiological problem. Problems of this kind are even more complicated ina areas where the population is continually exposed to other harmful man-made factors. The city of Kamensk-Uralsky (Sverdlovsk region, Russia) is a good case in point. In 1957, part of Kamensk-Uralsky was contaminated as the result of an accident at the Kyshtym nuclear plant. In addition, the population of the contaminated area is being exposed to atmospheric emissions from several industrial enterprises. Two comparable groups of residents were formed: one in the contaminated are and another in a control area within the same city characterized by similar levels of chemical pollution but substantially lower radioactive contamination. The groups were composed of only those people who had been living in these areas continually since time of the accident and who were under 15 years of age at the time of the accident. The groups were matched by sex, age, and socio-occupational characteristics. For each subject, data were gathered on more than 50 parameters including hematological, immunological, and biochemical indices of the health status. All these data were obtained from blood tests taken in the fall of 1992. Data processing was carried out with the help of a computerized mathematical pattern recognition methodology, which ensured reliable discrimination between the generalized health status in the areas under study. We found that the health status of inhabitants of the area more contaminated with radioactive fallouts was adversely affected by radiation.

Prediction of the comparative intensity of pneumoconiotic changes caused by chronic inhalation exposure to dusts of different cytotoxicity by means of a mathematical model.

A multicompartmental mathematical model has been used to simulate variations in the cytotoxicity of dusts in the kinetics of the retention, in the pulmonary region and tracheobronchial lymph nodes, of practically insoluble quartzite and titanium dioxide dust particles deposited on the free surfaces of the acini from alveolar air. Experiments with these dusts were conducted on rats exposed to virtually the same dust concentrations in the air for an experimental period of 20 weeks and a period of 10 weeks after exposure. Satisfactory approximation to the experimental data on the retention of these dusts is obtained by using the model parameters that depend either on damage to lung macrophages by phagocytosed particles or on the response of the host organism to this damage by enhanced recruitment of neutrophilic leucocytes; all the other variables of the model being unchanged. The values of the "action integral" computed from this model and multiplied by the index of comparative cytotoxicity of particles in vitro satisfactorily approximate to quantitative differences in the intensity of pneumoconioses caused by the dusts under study by the end of the experimental period. On the whole, the results of the mathematical model agree with the hypothesis that the cytotoxicity of particles plays a key part in both the process of retention of dust in the lung parenchyma and lung associated lymph nodes, and the pathological process caused by the retained dust. Thus given the factors and conditions on which the deposition of practically insoluble dusts in the pulmonary region depends, it is necessary to take into account the multiplicative nature of these two effects of cytotoxicity when predicting the comparative risk of pneumoconiosis.

[Effectiveness of glutamate in the treatment of early manifestations of occupational fluorosis]. / Otsenka effectivnosti glutaminovoi kisloty kak sredstva korrektsii rannikh proiavlenii professionalnogo fliuoroza.

Efficiency of glutamic acid for therapy of early signs of occupational fluorosis was studied in workers engaged into cryolite production. The study proved that use of glutamic acid in occupational conditions prevents progressing of metabolic disorders. The results encourage recommendations to include glutamate into therapeutic and prophylactic nutrition of workers exposed to fluor compounds, into nutritive additions according to special recipe.

[Experimental study on risk factors of pneumoconiosis caused by dust in the industry of new construction materials containing glass and coal waste]. / Eksperimentalnoe izuchenie pnevmokoniozoopasnosti pylevogo faktora v proizvodstve novogo tipa stroitelnykh materialov iz stekla i ugolnogo shlaka.

The study compared cytotoxicity and fibrogenic ability of quartzitic dust to that appearing at 3 sites of light building filler production based on ground glass or clinker. Obtained results prove possible pneumoconiosis development caused by exposure to such dust types, especially in the production using ground glass. The MAC in this type of production is 2 mg/cu m, for the dust in production using clinker the MAC is 4 mg/cu m.