The ice-breaking properties of amphibian aircushion vehicles (AACV), which have recently been discovered, [1] make it necessary to solve a number of new applied problems [2]. One of the promising methods of ice breaking with the aid of AACV is the resonance method [2] which is applied at speeds corresponding to maximum wave resistance. In this connection determination of the wave resistance to AACV under ice conditions becomes very important. In the absence of ice this problem has been theoretically solved for the movement of a vehicle in deep and shallow water [3, 4], in a channel [5], and with acceleration [6]. The present paper is concerned with the stationary problem of the wave resistance to AACV in broken ice.1. Let there be a given system of the AACV surface pressures moving at a constant velocity u over an infinite water field covered by broken ice. In accordance with the principle of inverse motion, we assume that a load q(x, y) is applied to the free liquid surface covered by broken ice and moving with velocity -u as x --~ oo.The coordinate system that is stationary relative to the vehicle is located as follows: the plane xOy coincides with the unperturbed ice-water interface, the x axis points in the direction of the vehicle's motion, and the z axis points vertically upward. The water is assumed to be an ideal incompressible liquid with density p2. Broken ice is represented in the form of floating disconnected masses. Interaction forces between separate ice floes are ignored, and their dimensions are considered sufficiently small compared with the wavelength so that ice-floe bending does not occur [7]. Full-scale tests [2] show this approach to be quite justifiable in solving problems on the propulsive properties of AACV in ice broken by the resonance method.Use is made of the assumption that the field covered by broken ice is continuous [7], and the surface density coinciding with the floating-particle mass per unit area is given by the continuous function m(x,y) = plh --p~where p0 is the ice physical density; s(x, y) is a dimensionless function of ice-floe tightness [7] (0 ~ s ~ 1); and h(x, y) is the ice thickness. To simplify the problem, the quantities h and s are further considered constant.In the adopted coordinate system, the velocity potential ~p(x,y, z) of fluid perturbed motion must satisfy the Laplace equation A T = 0 and the linearized boundary conditions z =0: 02~~ 0~o g Oqa plh 03~o _ 10q 0qo 0.(1.2) Oz 2 tt-~z + ~-g; + p20zOz 2 p2u 0-7' z = -H : 0---~ =Here tt > 0 is the coefficient of scattering forces [3, 8]; H = H1 -a; H1 is the water-body depth; and a = hp~ is the ice immersion depth at static equilibrium. For great depths, when H1 >> h, it can be assumed that H ~ H1.According to [3, 9], the wave resistance to AACV is numerically equal to the horizontal projection of the resultant of pressure forces onto the surface R // Ow(z, = q(x,y) -~xY)dxdy, (1.3)
We made recombinant antigen GE containing fragment of VZV glycoprotein E (Gly48 - Glu135) fused to E. coli beta-galactosidase and confirmed its antigen specificity by Western blotting and competitive-inhibition enzyme immunoassay (EIA) in comparison with commercial analogues and natural viral antigens. We showed interaction of recombinant GE protein with IgG antibodies from rabbits immunized by vaccine viral strain. GE protein also specifically reacted in ELISA with 66% of sera from zoster patients and 35% of sera from control groups including sera containing antibodies to other herpes viruses, sera from healthy donors, and sera from patients with different forms of intestinal disorders. Consequently, we demonstrated possibility of application of our recombinant GE VZV as antigen for diagnostics and research use.
Aim. The development of the hepatitis E virus (HEV) genotype 1 recombinant capsid protein. Materials and methods. Escherichia coli strains, plasmid vectors, serological and clinical samples, ELISA reagent kits, molecular biological, bioinformatic, biotechnological, biochemical and serological methods. Results. Using HEV genotype 1 DNA copy of subgenomic virus RNA we made E.coli strains producing recombinabt capsid protein, containing C-terminal fragment of ORF2 protein fused to E.coli beta-galactosidase. Recombinant protein ORF2 had been isolated from the inclusion bodies of the E.coli biomass and purified by size exclusion chromatography. By Western blotting it had been shown specific interaction of the recombinant polypeptide with anti-HEV IgG from pool of positive sera. Antigenic specificity of the recombinant polypeptide had been confirmed by enzyme-linked immunosorbent assay with sera of hepatitis E patients and reference groups: healthy donors, patients with hepatitis А, В, C, infectious mononucleosis and cytomegalovirus infection, HIV-infected patients. Conclusion. HEV genotype 1 ORF2 recombinant antigen had been developed, and its possible use in diagnostic tests had been experimentally shown.
Aim. Design аис1 construction of the hepatitis E virus (HEV) genotype 3 full-size ORF3 recombimnt polypeptide. Materials and methods. Escherichia coli strains, ptasmid vectors, serologiral and biological amples, molecular biological, bioinformatic, biotechnological, biochemical and serological methods.Results. RNA was isolated from pig fecal extracts collected on Belgorod farms and was used in RT-PCR to obtain the fragment of the orf3 gene of the hepatitis E virus genotype 3. Using A/T-cloning a recombinant plasmid was obtained with insertion of a DNA fragment (230 bp) encoding the N-terminal region of the ORF3 protein. The primary structure of the missing C-terminal region of the ORF3 VGE of the genotype 3 was calculated by bioinformatics methods. Codon optimization of the sequence for biosynthesis in E.coli cells was performed. For constructing the recombinant plasmid a chemically synthesized DNA fragment encoding the fulllength ORF3 protein had been used. E.coli strain producing full-size recombinant protein ORF3 fused to E.coli beta-galactosidase was developed. Recombinant protein ORF3 had been isolated from the inclusion bodies of the E.coli biomass and purified by size exclusion chromatography. Antigenic specificity of recombinant polypeptide had been confirmed in immunochemical reactions (ELISA, Western blot) with sera from patients with hepatitis E and control groups of patients. Conclusion. HEV genotype 3 ORF3 recombinant antigen had been designed, and itfs applicability in diagnostic tests had been experimentally confirmed.
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