Blazar spectral variability as explained by a twisted inhomogeneous jet.

Blazars are active galactic nuclei, which are powerful sources of radiation whose central engine is located in the core of the host galaxy. Blazar emission is dominated by non-thermal radiation from a jet that moves relativistically towards us, and therefore undergoes Doppler beaming. This beaming causes flux enhancement and contraction of the variability timescales, so that most blazars appear as luminous sources characterized by noticeable and fast changes in brightness at all frequencies. The mechanism that produces this unpredictable variability is under debate, but proposed mechanisms include injection, acceleration and cooling of particles, with possible intervention of shock waves or turbulence. Changes in the viewing angle of the observed emitting knots or jet regions have also been suggested as an explanation of flaring events and can also explain specific properties of blazar emission, such as intra-day variability, quasi-periodicity and the delay of radio flux variations relative to optical changes. Such a geometric interpretation, however, is not universally accepted because alternative explanations based on changes in physical conditions-such as the size and speed of the emitting zone, the magnetic field, the number of emitting particles and their energy distribution-can explain snapshots of the spectral behaviour of blazars in many cases. Here we report the results of optical-to-radio-wavelength monitoring of the blazar CTA 102 and show that the observed long-term trends of the flux and spectral variability are best explained by an inhomogeneous, curved jet that undergoes changes in orientation over time. We propose that magnetohydrodynamic instabilities or rotation of the twisted jet cause different jet regions to change their orientation and hence their relative Doppler factors. In particular, the extreme optical outburst of 2016-2017 (brightness increase of six magnitudes) occurred when the corresponding emitting region had a small viewing angle. The agreement between observations and theoretical predictions can be seen as further validation of the relativistic beaming theory.

[Serologic study of experimental cholera polymer antigen diagnosticums].

AIM: Evaluation of quality indicators of constructed cholera antigen polymer diagnosticums by using a complex of specific anti-cholera sera. MATERIALS AND METHODS. Cell lysates of cholera vibrio strains Vibrio cholerae cholerae 1395, V. eltor Ogawa 2044, V. eltor Inaba 13020, V. cholerae O139 16064 were sensitins for experimental preparations. 3 sera from cholera patients, normal human sera, cholera O1 (Ogawa, Inaba) commercial horse, cholera O139 commercial rabbit and heterologic sera against shigella, salmonella, escherichia and yersinia as well as experimental cholera rabbit sera against O1 and O139 were used as control. RESULTS: The study established that diagnosticums based on V. cholerae cholerae 1395 and V. cholerae O139 16064 strain sensitins by quality indicators may be used in the future for construction of these diagnosticums. CONCLUSION: Antibody containing preparations--commercial horse O1 sera, rabbit experimental and commercial sera and MCA O139 demonstrating titers not lower than 1/5120-1/10240 may serve as a control of experimental diagnosticums in the absence of human sera from cholera patients.

[The development of polymer immunoglobulin preparations to identify different serovars legionella pneumophilia in reaction of slide-agglutination].

The article deals with the results of study targeted to develop polymer diagnostic preparation to identify epidemically significant serogroups Legionella pneumophilia. The preparation combines rate of record (1-5 min) of reaction of paragglutinining preparations with color visualization and demonstrative of reaction of volume agglomeration with polymer diagnosticums. The specially synthesized polymer microspheres were sensibilized with serums enriched with antibodies to lipopolysaccharide of corresponding serovar L. pneumophilia. The derived immunoglobulin diagnostic preparations detect agent of legionellesis in the reaction of slide-agglutination on glass during 1-5 min. The polymer diagnostic preparations provide positive reaction with culture of corresponding serovar and no reaction with other gomologic and geterologic agents of infectious diseases.

[Serologic diagnostics of Legionella infection].

Technical approaches to construction of preparations for serologic diagnostics of Legionella infection were presented in the article; antigenic- and immunoglobulin-based diagnostic kits with known characteristics were developed. Immunogenic properties of protein and lypopolysaccharide antigens, which have diagnostic value, were studied; similarity of protein antigens from 7 serogroups of L. pneumophila was demonstrated. Soluble antigen with known composition was obtained and used for the development of antigen-based polymeric kit for diagnostics of Legionella infection. On the basis of hyperimmune sera, immunoglobulin-based polymeric diagnostic kit and array of coagglutinating diagnostic kits for the mentioned 7 serogroups were developed. Antigen-based polymeric diagnostic kit was recommended for licensure.

[The search for and isolation of an antiphagocytic factor in Francisella tularensis]. / Poisk i vydelenie antifagotsitarnogo faktora Francisella tularensis.

In this study a search for F. tularensis antiphagocytic factor and an attempt for its isolation were made. For this purpose a fraction of F.tularensis water-saline extract saturated 55-60% with ammonium sulfate was split into separate components by preparative methods. One of them, consisting of two antigens of glycoprotein nature, had the capacity of decreasing the digestion of F.tularensis by guinea pig peritoneal macrophages about 10 times. The study revealed that the protein of the preparation obtained in this investigation was capable of suppressing digestion, thus facilitating the active proliferation of F.tularensis inside the cells of the host body.

[The dynamics of antibody formation to a vaccinal strain of Francisella tularensis in different immunization regimens]. / Dinamika obrazovaniia antitel k vaktsinnomu shtammu Francisella tularensis pri razlichnykh skhemakh immunizatsii.

The use of different schemes of albino mice immunization either by living or by killed preparations of the vaccine strain of Francisella tularensis when obtaining monoclonal antibodies to the tularemia microbe made it possible to reveal definite regularities in the dynamics of antibody formation. The highest titres of antibodies in sera of animals-donors of splenocytes were obtained during the daily (for 3 days) intraperitoneal immunization of mice with living vaccine or with its thrice administration to the spleen thrice with the interval of 10 days. Revaccination against a background of high titres of antibodies decreased their quantity in blood serum of mice, while that against a background of low titres increased them.