Selective laser melting of low-alloyed titanium based alloy with a large solidification range.

In this work, thermodynamic calculations for α + ß Type Ti-Fe-Cu-Sn alloy were carried out by the Thermo-Calc software. Powders from this alloy were obtained by plasma sputtering and used for subsequent 3D printing of experimental samples. The effect of various selective laser melting (SLM) parameters on porosity and hot cracking susceptibility as well as the electrochemical characteristics of the alloy have been studied. The optimal technological regime for the manufacture of samples by the SLM method was determined. It has been established that to obtain relatively dense samples without cracks, regimes with volumetric energy density Ev = 250-300 J/mm3 are required. It has been established that a change in the electrochemical behavior of the Ti94Fe1Cu1Sn4 alloy is related to the formation of a nonequilibrium Ti2Cu phase. Based on the findings we recomended directions for further research.

X-Ray Diffraction and Multifrequency EPR Study of Radiation-Induced Room Temperature Stable Radicals in Octacalcium Phosphate.

Octacalcium phosphate (OCP) {Ca8H2(PO4)6×5H2O] has attracted increasing attention over the last decade as a transient intermediate to the biogenic apatite for bone engineering and in studies involving the processes of pathological calcification. In this work, OCP powders obtained by hydrolysis of dicalcium phosphate dehydrate were subjected to X- and γ-ray irradiation and studied by means of stationary and pulsed electron paramagnetic resonance at 9, 36 and 94 GHz microwave frequencies. Several types of paramagnetic centers were observed in the investigated samples. Their spectroscopic parameters (components of the g and hyperfine tensors) were determined. Based on the extracted parameters, the induced centers were ascribed to H0, CO33-, CO2- and nitrogen-centered (presumably NO32-) radicals. The spectroscopic parameters of the nitrogen-centered stable radical in OCP powders were found to be markedly different from those in hydroxyapatite. According to X-ray diffraction data, γ-ray irradiation allowed the phase composition of calcium phosphates to change; all minor phases with the exception of OCP and hydroxyapatite disappeared, while the OCP crystal lattice parameters changed after irradiation. The obtained results could be used for the tracing of mineralization processes from their initiation to completion of the final product, identification of the OCP phase, and to follow the influence of radiation processes on phase composition of calcium phosphates.

[Immunogenicity and safety of vaccine preparations based on circulating Bordetella pertussis strains].

AIM: Study specific activity and safety ofvaccine preparations based on circulating B. pertussis strains with currently predominating allele variants of pertussis toxin (ptxA1) and pertactin (prn2) genes. MATERIALS AND METHODS: B. pertussis strains isolated from pertussis patients in Moscow in 2001-2010 were grown in dense and liquid media. The content of separate antigens in B. pertussis strains was determined by EIA. Immunogenicity and safety of the preparations was determined in F1(CBAxC57B16) line mice. RESULTS: All the studied circulating B. pertussis strains expressed pertussis toxin (PT), filamentous hemagglutinin (FHA) and agglutinogens corresponding to the serovar. Whole-cell and acellular pertussis vaccines were prepared based on the circulating strains, and a highly productive recently isolated toxigenic B.pertussis strain that could be used for production ofpertussis vaccines was selected as a result of studies ofimmunogenic, toxic and sensibilizing properties. CONCLUSION: Vaccine preparations based on a B. pertussis strain adapted to growth in liquid media with pertussis toxin and pertactin ptxAl1 - prn2 gene allele variation characteristic for contemporary population are specifically active and safe.

[Production of pertussis toxin by Bordetella pertussis strains isolated from patients with whooping cough].

AIM: To assess level of pertussin toxin (PT) production by vaccine strains of Bordetella pertussis and strains isolated from patients with whooping cough. MATERIALS AND METHODS: Concentration of PT in supernatants of microbial cultures of 3 vaccine strains and 25 strains of B. pertussis isolated from patients with pertussis in 2001 - 2005 was measured with enzyme immunoassay using gamma-globulin fractions of rabbit antiserum to PT as immunosorbent or included in peroxidase conjugates. RESULTS: Level of PT production by strains isolated from infected persons varied from 3 +/- 0.5 to 64.8 +/- 12.2 ng/MFU/ml: in 9 strains--from 3 +/- 0.5 to 9.4 +/- 2.1 ng/MFU/ml, in 7--10.5 +/- 1.8 to 18.4 +/- 2.6 ng/MFU/ml, and in 9--23.6 +/- 4.5 to 64.8 +/- 12.2 ng/MFU/ml. CONCLUSION: B. pertussis strains isolated from patients were heterogeneous on level of PT production. Difference in expression of PT between strains were as high as 20-fold. Conditionally low, moderate and high levels of PT production had 9 (36%), 7 (28%), and 9 (36%) of 25 studied strains. Three vaccine strains had levels of toxin production similar to recently isolated strains with moderate level of its production.

[Dynamics of changes in pathogenic characteristics of Bordetella pertussis strains].

AIM: To study pathogenic characteristics of B. pertussis strains isolated from patients during different periods of pertussis infection epidemic process. MATERIALS AND METHODS: Strains of B. pertussis isolated in Moscow during 1967 - 1971, 1980 - 1985, and 2001 - 2005 were studied. Nutrient media: Bordet-Gengou blood agar, casein-charcoal agar. ANIMALS: mice - F1 hybrids (CBA x C57BL6). Pathogenic characteristics of strains were studied by assessment of virulence (LD50), leukocytosis-stimulating (LS units) and histamine-sensitizing (HSD50) activities of cultures. Genotyping was performed using standard equipment and reagents for DNA isolation, amplification, sequencing and detection of results. RESULTS: On the sample of 164 strains, pathogenic and genotypic characteristics of B. pertussis populations circulated during 1967 - 1971, 1980 - 1985, and 2001 - 2005. Majority of B. pertussis strains isolated in 1967 - 1971 and strains circulated during current phase of epidemic process were virulent (80.75% and 81.8% respectively) and had significant leukocytosis-stimulating and histamine-sensitizing activity, whereas strains isolated from patients with pertussis in 1980 - 1985 characterized by lower virulence and toxicity. Genotyping showed strains carrying "non-vaccine" allele ptxA1, which emerged in the middle of 1970s, totally displaced strains with "vaccine" alleles ptxA2 and ptxA4. CONCLUSION: Adaptive changes of B. pertussis driven by increased vaccination coverage involve both ptxA gene and pathogenic characteristics of infectious agent in the range of genotypically homogenous population with domination of strains, which have high levels of virulence and toxicity.

[Modern strains of Bordetella pertussis: immunobiological properties and vaccine improvement].

Strains of B. pertussis isolated from patients in Moscow in 2001-2005 as well as strains included in locally produced diphtheria-tetanus-whole cell pertussis (DTP) vaccine were studied. Nucleotide sequences in genes of pertactin and S1-subunit of pertussis toxin of isolated strains, their immunobiological properties and opportunity to use for producing of the acellular pertussis vaccine were determined. Genes of pertactin and S1-subunit of pertussis toxin in the isolated wild strains differed from the same genes in strains included in the local DTP vaccine. Majority of the isolated strains belonged to serotype 1.0.3 and were markedly virulent.

[Natural autoantibodies against MP65 and ACBP14/18 and ontogenic formation of rat nervous system]. / Estestvennye autoantitela k belkam MP65 i ACBP14/18 i ontogeneticheskoe formirovanie nervnoi sistemy krys.

It was demonstrated that passive immunization of pregnant female rats against MP65 and ACBP14/18 proteins leads to stable changes in offspring behavior (deviations in acquisition of active avoidance in a shuttle-box and changes in the open-field behavior). Immunomorphological data about localization of MP65 and ACBP14/18 proteins in brain slices of adult rats and rat embryos are presented. The obtained results are discussed in terms of the influence of maternal humoral immunity on the formation of fetal nervous system during intrauterine development.