Giant optical anisotropy in transition metal dichalcogenides for next-generation photonics.

Large optical anisotropy observed in a broad spectral range is of paramount importance for efficient light manipulation in countless devices. Although a giant anisotropy has been recently observed in the mid-infrared wavelength range, for visible and near-infrared spectral intervals, the problem remains acute with the highest reported birefringence values of 0.8 in BaTiS3 and h-BN crystals. This issue inspired an intensive search for giant optical anisotropy among natural and artificial materials. Here, we demonstrate that layered transition metal dichalcogenides (TMDCs) provide an answer to this quest owing to their fundamental differences between intralayer strong covalent bonding and weak interlayer van der Waals interaction. To do this, we made correlative far- and near-field characterizations validated by first-principle calculations that reveal a huge birefringence of 1.5 in the infrared and 3 in the visible light for MoS2. Our findings demonstrate that this remarkable anisotropy allows for tackling the diffraction limit enabling an avenue for on-chip next-generation photonics.

Direct and inverse problems in x-ray three-crystal triple Laue case interferometry.

We study the mechanisms of forming x-ray moiré images arising under the action of one-dimensional rows of local concentrated forces at the output surface of a triple-crystalline triple Laue case interferometer for the cases of their orientation parallel and perpendicular to the vector of diffraction. The presence of constant phase shift of one of the interfering waves in the interferometer's analyzer results in the diminishing of period, contrast, and area of deformation moiré fringes. It is shown that the area of efficient interaction of phase and deformation moirés depends on both the magnitude of the constant phase shift and the magnitude and character of arrangement of local concentrated forces in rows.

[Actual problem of methodology and development of evidence-based health risk assessment associated with chemical exposure].

Paramount problems of the development of the assessment of population health risks associated with the chemical exposure in Russia are considered on the ground of critical analysis of reports devoted to methodological issues of the risk assessment and guidelines published since 2010. Causes of the lack in progress of risk assessment are discussed. The information of executed research revealed the significant retardation number of Russian publications devoted to the evidence-based health risk assessment compare to worldwide trend. The analysis of publications according to evidence-based health risk assessment in Russia in 1998 - 2012 demonstrated methodical problems to be leading to the underestimation of the real risk to population's health. There are demonstrated directions in the renewal of methodology and practice of hygienic standardization on the basis of the risk assessment. The comparative analysis of values of uncertainty factors (modifying factors, conversion factors) used for extrapolation and accepted in different countries and organizations was made. The system of extrapolation coefficients of DNEL (Derive No-Effect Level) is presented. The leading principles of modern toxicology and risk assessment based on strict scientific proofs are showed. Criteria of evidence-based toxicology and risk assessment are presented.Among actual problems which demand their decision there are considered: the assessment of combined action in regulatory toxicology; expansion of spheres of the application of health risk assessment methodology; the improvement ofpreparation and certification of experts in the field of health risk assessment; need of check of dispersion models and their replacement by more modern models; the improvement of exposure assessment with taking into account the international requirements; the assessment of regional exposure factors; expansion of atmospheric air monitoring in all the large cities of Russia.

[COMPARATIVE ASSESSMENT OF THE MULTIMEDIA CANCER HEALTH RISKS CAUSED BY CONTAMINATION OF THE KRASNOIARSK KRAI REGIONS' ENVIRONMENT].

Krasnoyarsk Krai is a region with developed mining and processing industries, notoriously known industries, as sources of carcinogenic emission. For 55 administrative units of the Krai 303 large enterprises' industrial emissions were preliminary prioritized and their location was designated. Only 52% out of the carcinogens emitted into the ambient air by industries were controlled, in other environments the figures ranged from 20% (soil, food) to 48% (drinking water), 10 carcinogens were not controlled in the environment at all. Based on the results of ranking carcinogenic emission and analysis of the carcinogens monitoring in the environment in 2007-2011 31 substances were selected. A comparative analysis of multiple environmental carcinogenic risks showed that 78% of the areas, based on the receipt ofcarcinogensfrom two media, and 80% ofthe areas taking into account the receipt ofcarcinogens from three media attributed to the alarming level of risk for population, that requires continuous monitoring and routine health interventions for its mitigation. The maximal multiple environmental risk values that took into account inputs from all sources were close to the upper boundary alarming level of risk, in Divnogorsk (7,80E-04), Norilsk (7,97 E-04), Krasnoyarsk (8,84E-04) and Achinsk (9,4 E-04). The greatest inputs to total individual cancer risk from polluted ambient air were made by benzene, chromium VI, formaldehyde and nickel, from drinking water--by arsenic, aldrin and heptachlor from soil--by arsenic and lead. The ambient air input into total multiple environmental carcinogenic risk ranged from 31.5 to 99.5%, drinking water input--from 0.5 to 68.5%, soil--up to 0.1%. Areas with maximum levels of total carcinogenic risk are characterized by the highest levels of average long-term indices of cancer development. The study discussed in this article has screening nature. Further in-depth researches for carcinogenic and toxic multimedia risks are required.

[Results of health risk assessment due to exposure to contaminants in drinking water in Russia population (review of literature)].

With the purpose of the analysis of general trends in the development of risk assessment methodology in Russia the results obtained with the her help, as well as existing methodological problems, there was performed a review of 68 published works concerning the assessment of the health risk for population under the exposure to chemicals in drinking water carried out in 42 cities and regions of the country. There was made the grouping of Russian cities on individual carcinogenic risk level and ranking on the values for the population carcinogenic risk. A list of prioritized carcinogens in tap water has been made. By the values of the risk indices to adverse effects of chemicals tap water there are exposed central nervous system, kidneys, liver, skin and mucous membranes, blood, bone, immune system, hormone homeostasis, blood circulation and digestion organs. There are identified methodological problems leading to an underestimation of the actual risk to public health under exposure of chemicals in drinking water: there are no used regional and age differences in exposure factors, virtually there is no assessed health risk for children population; there is ignored age sensitivity to carcinogens, there is rarely estimated exposure for all the real exposing routes of income and there are no carried out risk calculations at the upper limit (90- 95th percentile) of the exposure.

[The urgent problems of the improvement of the environment management system based on the analysis of health risk assessment].

The lack of adequate legislative and regulatory framework for ensuring minimization of the health risks in the field of environmental protection is the obstacle for the application of the risk analysis methodology as a leading tool for administrative activity in Russia. "Principles of the state policy in the sphere of ensuring chemical and biological safety of the Russian Federation for the period up to 2025 and beyond", approved by the President of the Russian Federation on 01 November 2013, No PR-25 73, are aimed at the legal support for the health risk analysis methodology. In the article there have been supposed the main stages of the operative control of the environmental quality, which lead to the reduction of the health risk to the acceptable level. The further improvement of the health risk analysis methodology in Russia should contribute to the implementation of the state policy in the sphere of chemical and biological safety through the introduction of complex measures on neutralization of chemical and biological threats to the human health and the environment, as well as evaluation of the economic effectiveness of these measures. The primary step should be the legislative securing of the quantitative value for the term: "acceptable risk".

[Assessment of the effect of environmental chemicals on the working population in mono-cities].

There was made the characterization of the health risk for workers' of pulp and paper industry, under the simultaneous effects of chemicals in the residential and working area. The main adverse effect of chemicals that pollute the air and work environment is related with the impact on the respiratory system. Under the successive exposure (ambient air--air in the workplace) in the adult population working at the Arkhangelsk Pulp and Paper Mill, the risk of occurrence of respiratory diseases (HI = 18.5) and individual carcinogenic risk (CR = 9.7 x 10(-3)) have been rated as high and constitute 86-99% of the total risk.

[Problems in the system of state regulation of chemical safety].

In the paper the analysis of the problems of chemical safety abroad and in Russian Federation is presented, possible ways for their solutions, including the need for legal and scientific-methodical support for population health risk assessment are considered.

[Problems of improving the assessment of health risk for assurance of the sanitary and epidemiological well-being].

There are considered the current problems of improving population health risk assessment for assurance of the sanitary and epidemiological well-being. Their solution permit to improve the risk assessment methodology in Russia and overcome unnecessary barriers in the way of a practical application of the criteria of acceptable risk and damage to health to support management decisions.

[Results of analysis of ratios of indices of toxic and sensory effect of chemicals].

In the article there are presented results of the analysis of the quantitative relations between the parameters of toxicometry and indices of sensory effect of chemicals permitting to improve the accuracy of prediction of reference concentrations.

[Testing of the system of biochemical and immunological indices of the state of population health in the survey of residents of Moscow, exposed to ambient air pollution].

New biomarkers of effect of some controlled ambient air pollutants (formaldehyde, carbon monoxide and TSP) were found in two surveys of Moscow residents (apparently healthy and outpatients with allergic diseases) with a help of screening system of biochemical and immunological parameters. Possible mechanisms of the effects, including interference of atmospheric carbon monoxide and sulfur dioxide with corresponding endogenous second messengers, are discussed.

[Problems and ways of solutions to harmonize standards for air pollution].

In the article the basic problems of harmonization of domestic regulatory framework of air pollution with the WHO recommendations and normative values adopted in the EU, U.S. and other countries are considered. The important role of health risk analysis methodology in the process of harmonization of regulation and control of air quality has been pointed out. The necessity of radical changes in the structure and content of the basic normative document GN 2.1.6.1338-03 "maximum permissible concentration (MPC) of pollutants in the air of populated areas" has been shown. The algorithm of the procedure that justifies the new list of normative values in the air harmonized with international recommendations and standards of developed countries has been proposed.

[Approaches to assessing the health risk under exposure to chemicals with account of age peculiarities].

PURPOSE: To study the factors of exposure and to assess health risk in different age groups under exposure to chemical contaminants in drinking water in Novodvinsk. TECHNIQUES: Local exposure factors were studied by questionnaire in 1628 men in three age groups: 1-6 years, 7-17 years, 18 years and older. In the risk model three ways of exposure: inhalation, oral, and skin have been included. To assess the noncarcinogenic risk cumulative risk indices (CRI) were calculated, to evaluate a carcinogenic risk--the total carcinogenic risk (TCR), taking into account the correction for the age-specific cancer-causing potential was calculated. RESULTS: Quantity of water used for drinking for 1 kg of body weight in children of 1-6 years was 109 ml/kg-day, 7-17 years--55 ml/kg-day, and adults--34 ml/kg-day. At concentrations of contaminants of drinking water at 90th and 98th percentile the risk to the blood system exceeds the allowable level only for children in the group of 1-6 years (CRI = 1,8 and 3,7, respectively), taking into account age-specific for the total population TCR amounted to 4.3 x 10(-5) and 9.3 x 10(-5) correspondingly.

[Characteristics of quantitative values of regional factors of exposure in the studied areas].

In the paper the results of a comparative evaluation of the Russian and the standard, recommended by US EPA, factors of population exposure in seven areas of different federal districts of Russia are presented. Concerning the adult population differences reach 3.5 times, for children (1-6 years) - 4.2 times. An example of the effect of regional differences and standard factors on levels of exposure and risk is considered. Promising areas for further research on regional factors to improve the accuracy and reliability of the forecast assessments of the risks to public health have been identified.

[Population health risk from chemical air pollutants in a city with developed pulp and paper industry].

OBJECTIVE: to assess an effect of chemical contaminants contained in emissions of pulp and paper mill on prevalence respiratory and cardiovascular diseases in population of Novodvinsk. The average annual concentrations of chemicals of concern were calculated by modeling. A prevalence of population was studied by using of the primary medical documentation in sex among children from 0 to 17 and adults from 65 and older Hazard index (HIi) was used to assess the non-cancer health effects. Unit risk was used to calculate individual cancer risk (CR). Testing of null hypothesis was conducted by one-way analysis of variance (ANOVA) and ?2. The hazard index for respiratory tract (HIi = 3,54; 95% CI: 3.34-3.70) and cardiovascular system (HIi = 0.78; 95% /DE: 0.74-0.82) in the district close to the Arkhangelsk pulp and paper mill (APPM) were higher than in remote districts. In this district the prevalence of bronchial asthma in boys (30.7+13.8%), women (47.0+9.8%) and men (127.4+45.2%) was the highest. Also in this district the prevalence of hypertension among women (139.1+14.4%) and men (311.5+56.1%), diseases of veins among women (48.2+10.8%) and diseases of upper respiratory tract among men (177.0+36.4%) was higher than in remote districts from the APPM. The level of CR in the district located close by the APPM was acceptable (1.0 (10-5; 95% CI: 9.0 (10-6-1, 18(10-5).

[Demographic and socioeconomic determinants of health risk perception].

The aim of the investigation was to study the specific features of health risk perception in Novodvinsk dwellers in relation to gender, age, education, occupation, and income. A cross-sectional study was performed. The authors conducted a questionnaire survey of 695 subjects aged 18 years or older, who lived in Novodvinsk. Risk factors were ranked to define their hazard priorities. The chi2 test of the hypothesis that there are no differences in risk perception between different population groups was carried out. No statistically significant gender differences were found in high risk perception. Respondents less than 30 years of age are inclined to exaggerate the risk of chemical pollution of the environment as compared to 45 year olds (chi2 = 4.97; p = 0.025). It is more characteristic for subjects with a higher education and employees to refer lifestyle to as a high risk factor than for those who have lower education levels and workers (chi2 = 6.34; p = 0.010 and chi2 = 28.58; p < 0.001; respectively). Respondents with a specialized secondary education and workers more frequently regard radioactive pollution of the environment as a high risk (chi2 = 5.43; p = 0.019 and chi2 = 3.39; p = 0.050 and chi2 = 5.43; p = 0.019, respectively). Mean- and low-income subjects consider a low quality of life to be a high risk than those who have higher income (chi2 = 12.35; p < 0.01).

[Assessment of Moscow population health risk from exposure to ambient air suspended matter].

Ambient air pollution by suspended matter is an environmental factor that has the greatest influence on the health status of the majority of the Russian Federation's population. There is extensive epidemiological and clinical evidence suggesting that ambient air pollution by suspended matter and its fine-dispersed fractions PM10 and PM2.5 in particular, poses a serious threat to human health. The existing Russian single and average daily maximum permissible concentrations of suspended matter are not a high risk from this type of ambient air pollution and fail to assess human health damage in full measure. To reduce the concentrations of suspended matter and their action on man is currently the worldwide priority task whose performance will save much money. There is a need to change an air pollution monitoring system (continuous monitoring of fine suspended matter of PM10 and PM2.5), as well as to substantiate and introduce Russian hygienic standards for fine suspended matter (PM10 and PM2.5).

[Assessment of a risk from aviation noise exposure to the population's health].

The paper gives an algorithm, a procedure for calculation of aircraft noise, and its spread modeling. The performed investigations have provided guidelines that will become the first Russian official guiding document for assessing a risk from aviation noise to human health.

[Effect of weak static magnetic fields on the excitability of a neuron].

Changes in the excitability of the neuron (amplitude, excitability threshold, rate of action potential transduction), as well as changes in the viscosity of the plasma membrane of the nerve and membranes of subcellular organelles, induced by the action of a weak magnetic field, have been studied by the methods of extracellular registration of membrane potential and combination scattering. It was found that only the threshold of excitability in intact nervous fibers increases by the action of this field. It was proven that the conformation of C40 carotenoids localized not only in plasma membranes but also in subcellular membranes of the neuron changes in a weak magnetic field. It is assumed that the changes in the excitability of the neuron by the action of weak magnetic field are due to changes in the orderliness of membrane lipids and the content of oxygen in the cytoplasm.

[Prediction of acute inhalational effects in the assessment of a risk to human health].

The paper deals with a problem in choosing the criteria for a risk of acute inhalational exposures. It analyzes Russian, foreign, and international criteria for ambient air quality, by using the most authoritative sources (Agency of Toxic Compounds and Diseases Registration; Office of Environmental Health Hazard Assessment of US Environmental Protection Agency, etc.). The priority indices of the severity of acute toxic effects upon acute (within one hour) inhalational exposure to the most common ambient air pollutions (nitric dioxide, sulfur dioxide, carbon dioxide, and ozone) are determined. The issues of prediction of the regulated indices of evaluation of varying toxic effects on the population's health are considered. Valid models have been developed to predict the reference concentrations upon acute inhalational exposure to chemical substances, which allow the uncertainty in the assessment of the risk caused by acute exposure to ambient air pollutions to be reduced.