Mosaic loss of the Y chromosome in human neurodegenerative and oncological diseases.

The development of new biomarkers for prediction and early detection of human diseases, as well as for monitoring the response to therapy is one of the most relevant areas of modern human genetics and genomics. Until recently, it was believed that the function of human Y chromosome genes was limited to determining sex and controlling spermatogenesis. Thanks to occurance of large databases of the genome-wide association study (GWAS), there has been a transition to the use of large samples for analyzing genetic changes in both normal and pathological conditions. This has made it possible to assess the association of mosaic aneuploidy of the Y chromosome in somatic cells with a shorter lifespan in men compared to women. Based on data from the UK Biobank, an association was found between mosaic loss of the Y chromosome (mLOY) in peripheral blood leukocytes and the age of men over 70, as well as a number of oncological, cardiac, metabolic, neurodegenerative, and psychiatric diseases. As a result, mLOY in peripheral blood cells has been considered a potential marker of biological age in men and as a marker of certain age-related diseases. Currently, numerous associations have been identified between mLOY and genes based on GWAS and transcriptomes in affected tissues. However, the exact cause of mLOY and the impact and consequences of this phenomenon at the whole organism level have not been established. In particular, it is unclear whether aneuploidy of the Y chromosome in blood cells may affect the development of pathologies that manifest in other organs, such as the brain in Alzheimer's disease, or whether it is a neutral biomarker of general genomic instability. This review examines the main pathologies and genetic factors associated with mLOY, as well as the hypotheses regarding their interplay. Special attention is given to recent studies on mLOY in brain cells in Alzheimer's disease.

Cross-Polarization Optical Coherence Tomography for Clinical Evaluation of Dermal Lesion Degrees in Vulvar Lichen Sclerosus.

The aim of the study was to identify different degrees of dermal lesions in vulvar lichen sclerosus (VLS) using cross-polarization optical coherence tomography (CP OCT) based on attenuation coefficient to detect disease early manifestations and to monitor the effectiveness of treatment. Materials and Methods: The study included 10 patients without pathology and 39 patients with VLS diagnosed histologically. CP OCT was performed in vivo on the inner surface of the labia minora, in the main lesion area. From each scanning point, a 3.4×3.4×1.25-mm3 3D data array was obtained in 26 s. CP OCT examination results were compared with histological examination of specimens stained with Van Gieson's picrofuchsin.Quantitative analysis of OCT images was performed by measuring the attenuation coefficient in co-polarization and cross-polarization. For visual analysis, color-coded charts were developed based on OCT attenuation coefficients. Results: According to histological examination, all patients with VLS were divided into 4 groups as per dermal lesion degree: initial (8 patients); mild (7 patients); moderate (9 patients); severe (15 patients). Typical features of different degrees were interfibrillary edema up to 250 µm deep for initial degree, thickened collagen bundles without edema up to 350 µm deep for mild degree, dermis homogenization up to 700 µm deep for moderate degree, dermis homogenization and total edema up to 1200 µm deep for severe degree.Pathological processes in dermis during VLS like interfibrillary edema and collagen bundles homogenization were visualized using CP OCT method based on values of attenuation coefficient in co- and cross-polarization channels. However, CP OCT method appeared to be less sensitive to changes of collagen bundles thickness not allowing to distinguish thickened collagen bundles from normal ones with enough statistical significance. The CP OCT method was able to differentiate all degrees of dermal lesions among themselves. OCT attenuation coefficients differed from normal condition with statistical significance for all degrees of lesions, except for mild. Conclusion: For the first time, quantitative parameters for each degrees of dermis lesion in VLS, including initial degree, were determined by CP OCT method allowing to detect the disease at an early stage and to monitor the applied clinical treatment effectiveness.

[Possibilities of multiphoton microscopy for the diagnosis of the vulvar lichen sclerosus]. / Vozmozhnosti mul'tifotonnoi mikroskopii dlya diagnostiki skleroticheskogo likhena vul'vy.

BACKGROUND: Vulvar lichen sclerosus (VLS) is a chronic and recurrent dermatosis of an inflammatory nature with severe focal atrophy of the skin. Connective tissue changes are polymorphic and are still not taken into account in histological diagnostics due to the difficulty of interpreting routine histological methods. In this work, we use multiphoton microscopy (MPM) as a new imaging technique that provides detailed information about the organization of collagen fibers in the dermis based on a non-linear second harmonic generation (SHG) process. OBJECTIVE: To determine the degree of connective tissue damage in lichen sclerosus using standard histological techniques and to reveal the diagnostic capabilities of multiphoton microscopy. MATERIAL AND METHODS: We studied 42 biopsies with a histopathological diagnosis of VLS and 10 biopsies of normal vulvar skin. Histological, histochemical and immunohistochemical evaluation was used in comparison with MPM data. Quantitative analysis included the determination of the thickness, length of collagen fibers and the average intensity of the SHG signal. RESULTS: A comprehensive study of the skin showed 4 groups of changes that can be regarded as the degree of the dermis damage: initial, mild, moderate, severe. The affected area at the initial and mild degree has subtle changes, however, it is reliably identified by quantitative analysis of the SHG signal. So, the initial degree is characterized by thin (1.3-1.8 µm) long (56-69 µm) collagen fibers, with a moderate degree, the fibers are thickened (3.4-4.3 µm) and fragmented (22-37 µm). The affected area in moderate and severe cases undergoes homogenization, which is associated with the deposition of extremely thin (0.6-0.9 µm) short (16-28 µm) collagen fibers and the expression of type V collagen. CONCLUSION: Multiphoton microscopy in the second harmonic generation mode is a reliable method for identifying collagen fibers in tissues. The study made it possible to identify 4 degrees of the dermis damage in vulvar lichen sclerosus.

Microfluidic Chip as a Tool for Effective In Vitro Evaluation of Cyclophosphamide Prodrug Toxicity.

Most drugs are metabolized in the liver, which can lead to their activation or inactivation with a change in the parent compound pharmacology, as well as liver damage by active metabolites. Preclinical animal studies of drug safety do not always predict its effect on humans due to species specificity. Thus, for the rapid drug screening, and especially prodrugs, an in vitro system is required that allows predicting xenobiotic cytotoxicity with consideration of their metabolism in liver cells. The use of a microfluidic chip (BioClinicum) made it possible to cultivate a 2D culture of human HaCaT keratinocytes with spheroids of human hepatoma HepaRG cells. After incubation in a specially selected universal serum-free medium containing 3.8 mM cyclophosphamide, pronounced death of HaCaT cells was observed in comparison with culturing in the absence of liver cells.

Current Trends and Approaches to the Search for Genetic Determinants of Aging and Longevity.

Aging is a natural process of extinction of the body and the main aspect that determines the life expectancy for individuals who have survived to the post-reproductive period. The process of aging is accompanied by certain physiological, immune, and metabolic changes in the body, as well as the development of age-related diseases. The contribution of genetic factors to human life expectancy is estimated at about 25-30%. Despite the success in identifying genes and metabolic pathways that may be involved in the life extension process in model organisms, the key question remains to what extent these data can be extrapolated to humans, for example, because of the complexity of its biological and sociocultural systems, as well as possible species differences in life expectancy and causes of mortality. New molecular genetic methods have significantly expanded the possibilities for searching for genetic factors of human life expectancy and identifying metabolic pathways of aging, the interaction of genes and transcription factors, the regulation of gene expression at the level of transcription, and epigenetic modifications. The review presents the latest research and current strategies for studying the genetic basis of human aging and longevity: the study of individual candidate genes in genetic population studies, variations identified by the GWAS method, immunogenetic differences in aging, and genomic studies to identify factors of "healthy aging." Understanding the mechanisms of the interaction between factors affecting the life expectancy and the possibility of their regulation can become the basis for developing comprehensive measures to achieve healthy longevity. Supplementary Information: The online version contains supplementary material available at 10.1134/S1022795422120067.

[Heart damage in the combined types of systemic amyloidosis]. / Porazhenie serdtsa pri sochetannykh formakh sistemnogo amiloidoza.

The cardiovascular system is a common target of systemic amyloidosis (SA); amyloid light chain (AL) cardiac amyloidosis (AL-CA), the wild-type transthyretin (ATTRwt-CA), and mutant-type transthyretin (ATTRmt-CA) are the most studied types of SA. The literature describes only single cases of two types of SA in the same patient. OBJECTIVE: To identify and determine the clinical and morphological characteristics of combined types of SA in patients with biventricular chronic heart failure (CHF). MATERIAL AND METHODS: Eighty autopsy protocols for biventricular CHF deaths were retrospectively analyzed. Immunohistochemistry and confocal laser scanning microscopy (CLCM) with antibodies to amyloid A (AA), serum amyloid-P (SAP), prealbumin, and immunoglobulin kappa (κ) and lambda (λ) light chains were performed. RESULTS: The myocardium showed a combination of different types of SA in 6 (7.5%) cases, including Alλ-CA+ATTR-CA, ALκ-CA+ATTR-CA, and AA-CA+ATTR-CA in 4, 1, and 1 cases, respectively. Macroscopically, the heart mass averaged 470±20 g; the thickness of the left and right ventricular myocardium was 1.5±0.2 and 0.4±0.1 cm, respectively; the interventricular septum averaged 1.2±0.2 cm; and the cardiac index was 0.008. The myocardium was dense, dark red with diffuse layers of whitish dense fibrous connective tissue; the heart cavities were enlarged. Microscopically, in 25% of cases, all heart parts had ALλ-CA that was characterized by massive amyloid deposits localized predominantly in the intramyocardial vessel wall, intermuscular connective tissue, and perivascularly. The myocardium also displayed small amyloid deposits of ALλ-CA and ATTR-CA in the intermuscular connective tissue and intramyocardial vessel wall. Amyloid deposits were located in different parts of the myocardium; there were also areas of co-localization of ALλ-CA+ATTR-CA. CONCLUSION: The combined types of SA occurred under the guise of coronary heart disease and the dilated cardiomyopathy phenotype. The combined amyloid AL-CA and ATTR-CA was generally localized in the interstitium and myocardial vessels. There were also small areas of co-localization of amyloid deposits, which were found mainly in the intramyocardial vessels.

Alpha-B-Crystallin Effect on Mature Amyloid Fibrils: Different Degradation Mechanisms and Changes in Cytotoxicity.

Given the ability of molecular chaperones and chaperone-like proteins to inhibit the formation of pathological amyloid fibrils, the chaperone-based therapy of amyloidosis has recently been proposed. However, since these diseases are often diagnosed at the stages when a large amount of amyloids is already accumulated in the patient's body, in this work we pay attention to the undeservedly poorly studied problem of chaperone and chaperone-like proteins' effect on mature amyloid fibrils. We showed that a heat shock protein alpha-B-crystallin, which is capable of inhibiting fibrillogenesis and is found in large quantities as a part of amyloid plaques, can induce degradation of mature amyloids by two different mechanisms. Under physiological conditions, alpha-B-crystallin induces fluffing and unweaving of amyloid fibrils, which leads to a partial decrease in their structural ordering without lowering their stability and can increase their cytotoxicity. We found a higher correlation between the rate and effectiveness of amyloids degradation with the size of fibrils clusters rather than with amino acid sequence of amyloidogenic protein. Some external effects (such as an increase in medium acidity) can lead to a change in the mechanism of fibrils degradation induced by alpha-B-crystallin: amyloid fibers are fragmented without changing their secondary structure and properties. According to recent data, fibrils cutting can lead to the generation of seeds for new bona fide amyloid fibrils and accelerate the accumulation of amyloids, as well as enhance the ability of fibrils to disrupt membranes and to reduce cell viability. Our results emphasize the need to test the chaperone effect not only on fibrillogenesis, but also on the mature amyloid fibrils, including stress conditions, in order to avoid undesirable disease progression during chaperone-based therapy.

[Anatomical pathology of novel coronavirus (COVID-19) infection. First impressions]. / Patologicheskaya anatomiya novoi koronavirusnoi infektsii COVID-19. Pervye vpechatleniya.

To date, descriptive results of a clinical and morphological study of novel coronavirus COVID-19 infection, mainly of the lungs, have appeared. However, in other organs, primarily in the cardiovascular system, there are substantial structural changes that lead to multiple organ dysfunction and contribute to death. OBJECTIVE: To analyze the thanatogenetic significance of novel coronavirus COVID-19 infection in different age and gender groups and to describe the main morphopathological manifestations in various organs. MATERIAL AND METHODS: The investigators carried out a comprehensive analysis of 700 autopsies of people disease from the novel coronavirus COVID-19 infection, which included an examination of gross changes reflected in the autopsy protocols and forensic medical examination reports, as well as that of microscopic changes detected during histological examination of organs. Immunohistochemistry (IHC) using mouse or rabbit antibodies to CD34, CD68, EMA, Ki67, caspase-3, and VEGF was employed in some observations. RESULTS: The novel coronavirus COVID-19 infection was the primary cause of death. Acute respiratory and pulmonary heart failure and multiple organ dysfunction became the leading thanatogenetic mechanisms in COVID-19. Cardiovascular disease, diabetes mellitus, and obesity were the most common diseases in patients with COVID-19. The most pronounced lung changes in COVID-19 were determined with a predominance of multiple total bilateral lesions of the lower lobes of the lungs, which was manifested by virus-induced changes in the parenchyma and stroma, as well as by microcirculation disorders. Acute dyscirculatory and ischemic changes in the parenchymal organs dominated in tissue damage caused by the virus. CONCLUSION: The changes in different organs of those who have died from the new coronavirus COVID-19 infection are stereotyped and include the manifestations of virus-induced action and a systemic inflammatory response with mainly microvasculature alteration, which leads to the development of coagulopathies and, accordingly, to total hypoxia.

Denaturant effect on amyloid fibrils: Declasterization, depolymerization, denaturation and reassembly.

Accumulation of amyloid fibrils in organism accompanies many serious diseases, such as Alzheimer's and Parkinson's diseases, diabetes, prion diseases, etc. It is generally accepted that amyloids are highly resistant to degradation, which complicates their elimination in vivo and is one of the reasons for their pathogenicity. However, using a wide range of physicochemical approaches and specially elaborated method for the tested samples preparation by equilibrium microdialysis technique, it is proved that the stability of amyloids is greatly exaggerated. It turned out that amyloid fibrils formed from at least two amyloidogenic proteins, one of which is a model object for fibrils studying and the second is the cause of hemodialysis amyloidosis in an acute renal failure, are less stable than monomeric proteins. A mechanism of the degradation/reassembly of amyloid fibrils was proposed. It was shown that amyloid «seed¼ is a factor affecting not only the rate of the fibrils formation, but also their structure. Obtained results are a step towards identifying effects that can lead to degradation of amyloids and their clearance without adverse influence on the functionally active state of the protein or to change the structure and, as a result, the pathogenicity of these protein aggregates.

Effect of the fluorescent probes ThT and ANS on the mature amyloid fibrils.

Fluorescent probes thioflavin T (ThT) and 1-anilino-8-naphthalene sulfonate (ANS) are widely used to study amyloid fibrils that accumulate in the body of patients with serious diseases, such as Alzheimer's, Parkinson's, prion diseases, etc. However, the possible effect of these probes on amyloid fibrils is not well understood. In this work, we investigated the photophysical characteristics, structure, and morphology of mature amyloid fibrils formed from two model proteins, insulin and lysozyme, in the presence of ThT and ANS. It turned out that ANS affects the secondary structure of amyloids (shown for fibrils formed from insulin and lysozyme) and their fibers clusterization (valid for lysozyme fibrils), while ThT has no such effects. These results confirm the differences in the mechanisms of these dyes interaction with amyloid fibrils. Observed effect of ANS was explained by the electrostatic interactions between the dye molecule and cationic groups of amyloid-forming proteins (unlike hydrophobic binding of ThT) that induce amyloids conformational changes. This interaction leads to weakening repulsion between positive charges of amyloid fibrils and can promote their clusterization. It was shown that when fibrillogenesis conditions and, consequently, fibrils structure is changing, as well as during defragmentation of amyloids by ultrasonication, the influence of ANS to amyloids does not change, which indicates the universality of the detected effects. Based on the obtained results, it was concluded that ANS should be used cautiously for the study of amyloid fibrils, since this fluorescence probe have a direct effect on the object of study.

Plutonium production and particles incorporation into the human body.

Plutonium is one of the most toxic radioactive substances known. The isotope 239Pu gained attention when it had become known as a potential explosive material for atomic bombs. This paper describes the main problems encountered during the early years of operation of the first plutonium production plant in the former Soviet Union, the Mayak Production Association (Mayak PA). Mayak PA caused severe radioactive contamination of the environment and exposure personnel and population living in the vicinity areas to high radiation doses. The authors focus on key findings of large-scale studies on the internal dosimetry of workers for use in assessment of radiological risks from exposure to plutonium. This work presents an overview of the important issues for inhalation dose assessments such as generation of plutonium particles, plutonium intake, dissolution of plutonium particles, distribution of plutonium in humans, related exposures and health effects. Understanding the relationship between health effects, radiation dose and route of exposure helps quantify the health risks associated with occupational exposure in the nuclear industry and validate the radiation protection standards used in the Russian Federation and worldwide.

Brown bear attacks on humans: a worldwide perspective.

The increasing trend of large carnivore attacks on humans not only raises human safety concerns but may also undermine large carnivore conservation efforts. Although rare, attacks by brown bears Ursus arctos are also on the rise and, although several studies have addressed this issue at local scales, information is lacking on a worldwide scale. Here, we investigated brown bear attacks (n = 664) on humans between 2000 and 2015 across most of the range inhabited by the species: North America (n = 183), Europe (n = 291), and East (n = 190). When the attacks occurred, half of the people were engaged in leisure activities and the main scenario was an encounter with a female with cubs. Attacks have increased significantly over time and were more frequent at high bear and low human population densities. There was no significant difference in the number of attacks between continents or between countries with different hunting practices. Understanding global patterns of bear attacks can help reduce dangerous encounters and, consequently, is crucial for informing wildlife managers and the public about appropriate measures to reduce this kind of conflicts in bear country.

Structural Analogue of Thioflavin T, DMASEBT, as a Tool for Amyloid Fibrils Study.

Fluorescent dye trans-2-[4-(dimethylamino)styryl]-3-ethyl-1,3-benzothiazolium perchlorate (DMASEBT) is a relatively recently synthesized probe for detection of amyloid fibrils accumulating in the organs and tissues of patients with a wide range of serious incurable diseases. DMASEBT was developed as an alternative of its widely used analogue thioflavin T (ThT), which is the "gold standard" for the amyloid fibrils study. Our results show the similarity of both dyes binding to amyloid fibrils and allow one to propose a mechanism of such probes interaction with some types of the fibrils. At the same time, DMASEBT has a significant advantage, namely, improved photophysical properties compared with ThT, which allows for the detection of DMASEBT-stained amyloid fibrils in the spectral region of the "transparency window of biological tissues". The ability of the dye to penetrate into the cells was shown to open the prospect of this dye's use for amyloid fibrils bioimaging and biosensing in vivo. Furthermore, it was proven that DMASEBT can be used not only as a test for amyloid fibrils formation but also for the comparative study of the fibrils structure (both their fibers and bunches), which in turn may underlie the variability of amyloidosis and affect the cytotoxicity of these protein aggregates.

Enhancement of Declarative Memory: From Genetic Regulation to Non-invasive Stimulation.

The problem of memory enhancement is extremely important in intellectual activity areas and therapy of different types of dementia, including Alzheimer's disease (AD). The attempts to solve this problem have come from different research fields. In the first part of our review, we describe the results of targeting certain genes involved in memory-associated molecular pathways. The second part of the review is focused on the deep stimulation of brain structures that can slow down memory loss in AD. The third part describes the results of the use of non-invasive brain stimulation techniques for memory modulation, consolidation, and retrieval in healthy people and animal models. Integration of data from different research fields is essential for the development of efficient strategies for memory enhancement.

Thioflavin T Interaction with Acetylcholinesterase: New Evidence of 1:1 Binding Stoichiometry Obtained with Samples Prepared by Equilibrium Microdialysis.

The aim of the present work was investigation of the fluorescent dye thioflavin T (ThT) binding to acetylcholinesterase (AChE). ThT is an effective test for protease activity, as well as a probe for amyloid fibril formation. Despite the extended and active investigation of ThT-AChE binding, there is still no common view on the stoichiometry of this interaction. In particular, there is a hypothesis explaining the spectral properties of bound to AChE dye and high quantum yield of its fluorescence by formation of dimers or excimers of ThT. In order to confirm or deny this hypothesis, we proposed a new experimental approach for examination of ThT-AChE interaction based on spectroscopic investigation of samples prepared by equilibrium microdialysis. This approach allowed us to prove 1/1 ThT/AChE binding stoichiometry. The increase of ThT fluorescence quantum yield and lifetime accompanying its binding to AChE can be explained by the molecular rotor nature of this dye. Together with the coincidence of the positions of free and AChE-bound ThT fluorescence spectra, the obtained results prove the groundlessness of the hypotheses about ThT aggregation while binding to AChE. The model of ThT localization in the active site of AChE was proposed by using molecular docking simulations. These results also allowed us to suggest the key role of aromatic residues in ThT-AChE interaction, as observed for some amyloid fibrils.

Influence of electrical boundary conditions on profiles of acoustic field and electric potential of shear-horizontal acoustic waves in potassium niobate plates.

The profiles of an acoustic field and electric potential of the forward and backward shear-horizontal (SH) acoustic waves of a higher order propagating in X-Y potassium niobate plate have been theoretically investigated. It has been shown that by changing electrical boundary conditions on a surface of piezoelectric plates, it is possible to change the distributions of an acoustic field and electric potential of the forward and backward acoustic waves. The dependencies of the distribution of a mechanical displacement and electrical potential over the plate thickness for electrically open and electrically shorted plates have been plotted. The influence of a layer with arbitrary conductivity placed on a one or on the both plate surfaces on the profiles under study, phase and group velocities of the forward and backward acoustic waves in X-Y potassium niobate has been also investigated. The obtained results can be useful for development of the method for control of a particle or electrical charge movement inside the piezoelectric plates, as well a sensor for definition of the thin film conductivity.

Quantitative Analysis of L1-Retrotransposons in Alzheimer's Disease and Aging.

LINE1 retrotransposons are members of a class of mobile genetic elements capable of retrotransposition in the genome via a process of reverse transcription. LINE1 repeats, integrating into different chromosomal loci, affect the activity of genes and cause different genomic mutations. Somatic variability of the human genome is linked to the activity of some subfamilies of LINE1, in particular, a high level of LINE1 retrotranspositions has been observed in brain tissues. However, the contribution of LINE1 to genomic variability during normal aging and in age-related neurodegenerative diseases is poorly understood. We conducted quantitative real-time PCR analysis of active subfamilies of LINE1 repeats (aL1) using genomic DNA extracted from brain specimens of Alzheimer's disease (AD) patients and individuals without neuropsychiatric pathologies, as well as DNA extracted from blood specimens of individuals of different ages (healthy and AD subjects). Inter-individual quantitative variations of active families of aL1 repeats in the genome were observed. No significant age-dependent differences were identified. Likewise, no difference of aL1 copy number in brain and blood were indicated between AD patients and the aged-matched control group without dementia. These data imply that aging and the AD-associated neurodegenerative process are not the major factors contributing to the retrotransposition processes of active LINE1 repeats.

Gasoline sensor based on piezoelectric lateral electric field excited resonator.

It has been shown that by using piezoelectric lateral electric field excited resonators based on X - cut LiNbO3, one can determine the octane number of gasoline. The measured dependence of gasoline permittivity on its octane number has shown that there is an ambiguous connection between pointed parameters. We have demonstrated both theoretically and experimentally that the value of the real part of the electrical impedance on the frequency of parallel resonance uniquely associates with the octane number of gasoline contacting the free side of the resonator. At that the frequency of parallel resonance does not depend on permittivity/octane number of gasoline. An example of determination of the octane number of a mixture of two different samples of gasoline is given.

Unusual energy properties of leaky backward Lamb waves in a submerged plate.

It is found that leaky backward Lamb waves, i.e. waves with negative energy-flux velocity, propagating in a plate submerged in a liquid possess extraordinary energy properties distinguishing them from any other type of waves in isotropic media. Namely, the total time-averaged energy flux along the waveguide axis is equal to zero for these waves due to opposite directions of the longitudinal energy fluxes in the adjacent media. This property gives rise to the fundamental question of how to define and calculate correctly the energy velocity in such an unusual case. The procedure of calculation based on incomplete integration of the energy flux density over the plate thickness alone is applied. The derivative of the angular frequency with respect to the wave vector, usually referred to as the group velocity, happens to be close to the energy velocity defined by this mean in that part of the frequency range where the backward mode exists in the free plate. The existence region of the backward mode is formally increased for the submerged plate in comparison to the free plate as a result of the liquid-induced hybridization of propagating and nonpropagating (evanescent) Lamb modes. It is shown that the Rayleigh's principle (i.e. equipartition of total time-averaged kinetic and potential energies for time-harmonic acoustic fields) is violated due to the leakage of Lamb waves, in spite of considering nondissipative media.

[DEFINITION OF THE OPTIMUM MODES OF OPERATION OF AIR-MO- NITORING INSTRUMENTATION FOR DETECTION OF PATHOGENIC BIOLOGI- CAL AGENTS IN MODEL EXPERIMENTS].

AIM: To experimentally define the optimum modes ofoperation ofthe nonspecific detector IBAC integrated with C100 sampler and BioCapture sampler in model experiments during the work in various environmental conditions and at dispersion of the biological aerosol. MATERIALS AND METHODS: The nonspecific detector IBAC with the C100 sampler and the BioCapture sampler were used for air-monitoring test on existence of pathogenic biological agents (PBA). For preparation of the bioaerosols the strain of Salmonella typhimurium 9640 and a bull seralbumin were used. RESULTS: It is experimentally established that programming of IBAC on turning on the bioalarm system when maintaining concentration of bioaerosol in air above threshold level during 10 sec. is optimum. Its sensitivity makes 1x10³ m.c./ml of aerosol at this mode. The possibility of operation of air-monitoring instrumentation in various environmental conditions inside and outside is shown. CONCLUSION: As a result of the experi- ment the effectiveness of usage of the nonspecific detector IBAC with the C100 sampler and BioCapture sampler for air-monitoring on existence of PBA is proved. IBAC with C100 can be used as an inventory ofthe station ofair-monitoring during the public events, and BioCapture is suitable for equipment of the groups of epidemiological investigation.