Making of the clinicophysiological diagnosis within the system of medical flight certification

Adaptation responses were evaluated in flying personnel during medical examination with the use of simulators of the main dynamic factors of flight. Utility of assessing the adaptive reactions of the cardiovascular system by their physiological "cost" has been demonstrated. Parameters of the normal cardiovascular response to moderate hypoxia in altitude chamber have been established. On the basis of accumulated data, more sensitive and informative criteria for assessment of the functional state of the human organism are proposed for clinicophysiological diagnostics within the system of medical certification of flying personnel.     

Investigation of the Load-Carrying Capacity of Barretes for a 56-Storey Residential Building

Soil Mechanics and Foundation Engineering - We present the results of full-scale tests of barretes in the area of future building of a 56-storey residential building in Moscow. These tests were...     

Controlling the microporosity of SBA-15 silicate material by background salt solution

The structure of silicate material of the SBA-15 type has been studied under variable composition of a salt solution in synthesis. Ammonium and sodium chlorides, as well as ammonium fluoride, introduced into the composition of the reaction mixture both at the first stage of precipitation and at the second stage of the thermal treatment (TT), have been used as the salt additives. The mesostructure was controlled by X-ray diffraction, gas adsorption and transmission electron microscopy. It was found that the multiple increase of the ionic strength of the solutions in the presence of chloride salts disrupt the stoichiometry of the silicate-surfactant interaction at the first stage of formation of mesostructure and leads to the formation of an impurity of irregular structure. The ions of ammonium promote an increase in the microporosity of the silicate wall. The presence of sodium ions reduces microporosity. Small quantities of fluoride ions (F^?: Si = 0.032) improve the ordering of the product at the stage of primary precipitation. At the ratio F^?: Si = 0.16, the hexagonal mesostructure is not formed. The introduction of fluorides at the TT stage leads to a decrease of the silicate pore wall thickness, microporosity and hexagonality of the pore.     

Changes in the mesostructure and properties of MCM-41 depending on the formation medium

Changes in the mesostructure and hydrothermal stability of the MCM-41 silicate material, depending on the synthesis conditions have been investigated. The mesostructure was characterized by the X-ray structural analysis, adsorption surface measurements, and hydrothermal stability. Changes in the synthesis conditions consisted in changing the reaction solution basicity using ammonia and alkali and replacing the mother liquor used in hydrothermal treatment by water, as well as salt and alcohol-ammonia solutions. The increase of the pore diameter is caused, as a rule, by the water osmotic pressure. Moreover, if the silica polycondensation is slowed or sterically hindered, the pores acquire a hexagonal shape or, under conditions promoting polycondensation, a cylindrical one. Predominance of the hexagonal shape over the cylindrical one points to the reduced hydrothermal stability of the material. Pore wall consists of two-layer silica pack with thickness of 0.08–0.10 nm. Ammonia applying, as reaction medium basicity factor, provides maximal silica polymerisation rate and hight hydrothermal stability of the material.     

Surface topography of phytochrome A deduced from specific chemical modification with iodoacetamide

Phytochromes are a photoreversible photochromic light switch for photomorphogenesis in plants. The molecular structure and functional mechanism of phytochromes are not fully understood. On the basis of complete mapping of total tryptic digest of the iodoacetamide-modified oat phytochrome A (phyA), the molecular surface topography of phyA was probed by specific chemical modification of cysteine residues with [14C]iodoacetamide. Under native conditions, only two cysteines (Cys-158 and Cys-311) of eleven half-cystines of the N-terminal chromophore binding domain were modified to a significant extent. In the C-terminal domain, six cysteine residues (Cys-715, Cys-774, Cys-809, Cys-869, Cys-961, Cys-995) were readily accessible to iodoacetamide. Among the reactive cysteine residues, only cysteine-311 displayed reactivity that was dependent on the photochromic form (Pr left arrow over right arrow Pfr) of the photoreceptor. Surprisingly, the modification of Cys-311 in the vicinity of the chromophore attachment site (Cys-321) did not have any detectable effect on spectral properties of phyA. Most of the cysteines of the N-terminal domain (Cys-83, Cys-175, Cys-291, Cys-370, Cys-386, Cys-445, Cys-506) are deeply buried in the core of the chromophore binding domain, as they can be modified only after denaturation of the chromoprotein. In the C-terminal domain, modification of only one cysteine residue (Cys-939) required protein denaturation. Since all 22 half-cystines can be modified with iodoacetamide without reduction of the chromoprotein, it follows that oat phyA does not have any disulfide bonds. We found that Cys-311, Cys-774, Cys-961, and Cys-995 could be easily partially oxidized under the conditions used for phytochrome isolation. The surface topography/conformation of oat phyA and its role in protein-protein recognition in phytochrome-mediated signal transduction are discussed in terms of the relative reactivity of cysteine residues.     

Polyclonal antibodies from blood and cerebrospinal fluid of patients with multiple sclerosis effectively hydrolyze DNA and RNA

It is known that in the blood of patients with some autoimmune diseases catalytically active antibodies hydrolyzing proteins, DNA, and RNA may be detected. In the present work homogeneous preparations of IgG antibodies (Ab) possessing high affinity for nucleic acids (NA) were obtained for the first time from blood and cerebrospinal fluid of patients with multiple sclerosis (MS). The fraction of IgG Ab as well as its Fab fragments and isolated light chains of both kappa- and lambda-types were shown to catalyze effectively the hydrolysis of DNA and RNA. It is shown by different methods that the capability for nucleic acid hydrolysis is an intrinsic property of the polyclonal Ab. NA-hydrolyzing Ab were detected in the blood of 69 of 72 and in the cerebrospinal fluid of 5 of 5 examined MS patients, while they were not detected in the blood of any of 50 healthy donors examined. Comparison of relative rates of RNA hydrolysis and of the substrate specificity in hydrolysis of various model RNAs--cCMP, poly(U), poly(A), and poly(C)--revealed pronounced differences of MS antibodies from ribonucleases of human blood, ribonuclease A, and all earlier described abzymes. The abzymes are usually characterized by relatively low specific activities in comparison with that of normal enzymes catalyzing analogous reactions. Ab from the blood of MS patients are the first example of autoabzymes whose specific activity in RNA hydrolysis is comparable or even higher than that of pancreatic ribonuclease A--one of the most active RNA-hydrolyzing enzymes.