Single π 0 production off neutrons bound in deuteron with linearly polarized photons

The quasifree γ → d → π 0 n ( p ) photon beam asymmetry, Σ , has been measured at photon energies, E γ , from 390 to 610 MeV, corresponding to center of mass energy from 1.271 to 1.424 GeV, for the first time. The data were collected in the A2 hall of the MAMI electron beam facility with the Crystal Ball and TAPS calorimeters covering pion center-of-mass angles from 49 ∘ to 148 ∘ . In this kinematic region, polarization observables are sensitive to contributions from the Δ ( 1232 ) and N(1440) resonances. The extracted values of Σ have been compared to predictions based on partial-wave analyses (PWAs) of the existing pion photoproduction database. Our comparison includes the SAID, MAID and Bonn-Gatchina analyses; while a revised SAID fit, including the new Σ measurements, has also been performed. In addition, isospin symmetry is examined as a way to predict π 0 n photoproduction observables, based on fits to published data in the channels π 0 p , π + n and π - p .

Non-steady-state photo-EMF interferometer for detection of mechanical oscillations in transparent scattering objects

The operation of an adaptive non-steady-state photo-electromagnetic field (EMF) sensor is studied in an interferometric arrangement including a diffuse scattering object-fiber optic plate. The mechanical oscillations of this plate induce the strains and stresses of the medium, which modulates the phase of the propagating light wave across the plate. The resonant frequencies of the mechanical system and the distribution of the phase modulation amplitude across the plate's surface are measured. The minimal detectable stress amplitude is estimated.

Search for the Θ+ pentaquark via the π(-)p→K(-)X reaction at 1.92 GeV/c

The Θ(+) pentaquark baryon was searched for via the π(-)p→K(-)X reaction with a missing mass resolution of 1.4 MeV/c(2) (FWHM) at the Japan Proton Accelerator Research Complex (J-PARC). π(-) meson beams were incident on the liquid hydrogen target with a beam momentum of 1.92 GeV/c. No peak structure corresponding to the Θ(+) mass was observed. The upper limit of the production cross section averaged over the scattering angle of 2° to 15° in the laboratory frame is obtained to be 0.26 μb/sr in the mass region of 1.51-1.55 GeV/c(2). The upper limit of the Θ(+) decay width is obtained to be 0.72 and 3.1 MeV for J(Θ)(P)=1/2(+) and J(Θ)(P)=1/2(-), respectively, using the effective Lagrangian approach.

[Pre-morbid borderline state in teenagers]

There was effectuated a clinical-epidemiological, follow-up research of frequency, phenomenological peculiarities and dynamics of pre-existing disease borderline disorders among teenagers-schoolers. There were defined several factors, eintraechtigening on forming stable neurotic and personal disorders.

[Results and prospects of activities of military medical examination units in the Armed Forces of Russian Federation]

The role and place of military medical examination as one of the factors of national security in the system of medical support of the Armed Forces personnel is evaluated. National significance of military medical examination organs, legal and social character of medical expert conclusions which they draw is discussed. Characteristic of structure and dynamics of disease main indices causing difficulties in troop recruitment and servicemen discharge is given. Measures necessary for improvement of medical examination quality under modern conditions are mentioned.

[Military medical examination and social security of servicemen and members of their families]

In the article the main social privileges and guarantees stipulated by the laws of Russian Federation as well as the role and significance of military medical examination organs in the problems of social security of servicemen and persons underwent military service (military training) and members of their families are discussed. The authors emphasize legal significance of conclusions drawn by military medical commissions in examined persons for registration of invalidity, insurance payments, single-payment grants, compensation and privilege rights.

Mutagenic specificity of the base analog 6-N-hydroxylaminopurine in the LYS2 gene of yeast Saccharomyces cerevisiae

We used the LYS2 gene mutational system to study mutation specificity of the base analog 6-N-hydroxylaminopurine (HAP) in yeast. We characterized phenotypes of mutations using codon-specific nonsense suppressors and the test employing inactivation of the release factor Sup35 due to overexpression and formation of prion-like derivative [PSI]. We have shown that HAP induces predominantly nonsense mutations. While the tests using codon-specific nonsense-suppressors allowed to identify only about 50% of nonsense-mutations, all the nonsense-mutations were identified in the test with defective Sup35. We determined and analyzed the spectrum of HAP-induced nucleotide changes in two regions of the gene. HAP induces predominantly GC-->AT transitions in a hotspots of a central position of trinucleotide GGA or AGG. Directionality of these transitions is consistent with the idea that initial dHAPMP incorporation in the leading strand is more genetically dangerous than in lagging DNA strand. We revealed a specific context inhibitory for HAP mutagenesis, a "T" in -1 position to mutation site.

[Classification of myocardial dystrophies in aviation medical certification]

Myocardial dystrophy is one of the most common noncoronary lesions of the myocardium in pilots. However, the abundance of proposed classifications of myocardial dystrophies poses certain problems to medical experts. The authors attempt to consider the existing classifications from the standpoint of aviation medical certification and advocate the most acceptable, to their thinking, systematics by N.P. Paleev and L.I.Levitina (1991). Examples of establishing diagnoses of myocardial dystrophy are included. The best suited program for the aviation medical certification board to work out the final statement regarding the occupational fitness of pilots with myocardial dystrophy is proposed.

[The role of military medical expertise in preserving the mental health of servicemen]

The authors examine factors of mental dysadaptation, neurotic disorders' formation and psychopathy criminal reactions in draftees. An emphasis has been made on the clinical and psychological stages of dysadaptation and psycho-dysadaptation cases of pre-nosolologic levels. Some measures of improvement for military-medical panels have been offered.

[The clinico-epidemiological and medical expertise characteristics of neuropsychic morbidity in draftee contingents]

Official statistics show unfavourable growth tendencies of psychoneurological morbidity in younger generation in Russia, which creates recruitment problems for its Armed Forces. The authors offer a number of measures for preliminary checking-up of the drafted personnel to prevent potential patients from joining the Army.

[Criteria for determining the category of readiness for military service]

In connection with professionalization of the Armed Forces of Russian Federation there was the necessity of deep study of laws and theoretical bases of the estimation criterion of readiness to the military service of various quota of military personnel. In this article the approaches to the given problem decision are reflected. The authors consider, that the military-medical examination represents complex process of study and estimation of the biomedical and social status of the person, definition of his conformity to conditions of the military service, the correlation of diseases and injuries with military service, but also sanction of other questions with removal of the written conclusion. The scientific development of the methodical approaches to definition of estimation of criteria of readiness category to the military service on the basis of priority of medical criteria over social in peace time becomes now one of the major problem of the military-medical examination. The authors discussed the methodological and theory questions of military-medical examination. These disputable questions require further discussion and scientific substantiation.

[The organizational and methodological aspects of medical expertise work in the new Regulations on military medical expertise]

In Regulations about military medical examination the medical essence of fitness categories for the military service in peace and wartime, which were determined by Russian Federation law, have been worked out. The Regulations determine the most important legal norms of organization and conducting of military medical examination. List of diseases--the main functional part of Regulations--contains 89 articles (in previous--116) and 4 columns, which envisage the requirements to health state of the different categories of citizens. The article' names in List of diseases and there sequence are been adapted at most to International Disease Classification.

[In vitro immunization of human lymphocytes with Epstein-Barr virus capsid antigen]

Conditions for in vitro immunization of human lymphocytes from adult peripheral blood, tonsils and cord blood with Epstein-Barr Virus (EBV) capsid antigens have been studied. Pokeweed mitogen and B cell growth factor from Namalva cell line were shown to induce a significant production of specific antibodies by human lymphocytes stimulated with EBV. This effect made it possible to generate primary immune response in vitro using lymphocytes from EBV seronegative donors.

[Relation between DNA replication and neutral Mn 2+-dependent DNAse activity in chromatin]

In cultures of primary murine fibroblasts the 10% serum stimulates the replicative synthesis of DNA inhibited by aphidicolin and araC (cytosine arabinoside). Using direct immunofluorescence analysis, it was shown that antibodies penetrate inside the cells and after 4 hours are pooled in the nuclei, where they remain for another 20 hours. The substitution of antibodies against chromatin DNAase by bovine serum albumin of normal serum gamma-globulins does not interfere with the DNA synthesis induction.

[Results and prospects for the study of the morphologic basis of microcirculation of the blood]

The survey of the works, performed during the 11th five-year period in studying general biological regularities of microcirculation, demonstrates certain success in investigations developed in the following directions: functional geometry of the hemo-microcirculatory bed; elaboration of quantitative and qualitative analysis methods of the microcirculatory system elements; functional morphology of the vascular endothelium; experimental analysis of adaptive mechanisms of the microcirculatory bed; clinical-morphological investigations of microcirculation. Formation of structural-functional units, ensuring specialization of microcirculation in organs, forms the base of the functional geometry of the microcirculatory bed. This makes necessary conditions for compartmentalization of some micro-region in an organ and spatial distribution of various liquid media in dependence of certain topology of microvessels. The most perspective ways in development of morphological investigations, concerning the general biological regularities of microcirculation, are discussed.

[Comparative characteristics of human interleukin-2 preparations isolated from various sources]

Interleukin-2 (IL-2) was isolated from donor peripheral blood lymphocytes and from JURKAT T-lymphoma cells. The purification procedure including gel filtration on DEAE and CM-Sephadex resulted in a 400-fold increase of the enzyme specific activity. It was shown that optimal proliferation of T-lymphocytes occurs upon consecutive treatment of cells with phytohaemagglutinin and IL-2 as well as in the presence of a serum. The properties and procedure of isolation of the long proliferating line of IL-2-dependent T-cells B-5 were described. Proliferation of B-5 cells completely depended on the presence of IL-2 in the medium, although long-term proliferation occurred upon periodic stimulation of cells with the antigen (allogenic lymphocytes). In the absence of IL-2 B-5 cells decay within 36 hours. The perspective uses of IL-2 prepared from the cultural fluid of human peripheral blood lymphocytes for adoptive immunotherapy of tumours and the applicability of IL-2-dependent B-5 cells for testing the activity of IL-2 preparations from various sources are discussed.

[Ability of virus SV40 T-antigen to simulate the effect of specific T lymphocyte growth factor--interleukin-2]

The entering of T-lymphocytes into the DNA-synthesizing phase was marked by three consecutive signals, i.e., antigenic influence, interleukin-2, a specific T-lymphocyte cell growth factor, and non-specific serum growth-promoting factors, in the first place, transferrin. This system was used for the study of effects of virus SV40 T-antigen on cell mitotic cycle. Purified T-antigen was injected consecutively into T-lymphocytes, using erythrocyte ghost vesicles instead of one of control signals. It was shown that T-antigen cannot simulate the antigenic response but simulates the effect of interleukin-2, a specific growth-promoting factor. However, both normally proliferating T-lymphocytes and T-antigen-induced lymphocytes showed an absolute requirement for transferrin and, apparently, for other nonspecific growth-promoting factors. It was assumed that the polymorphism of tumours induced by papovaviruses is determined by the ability of their "early" proteins to imitate the effects of their specific growth-promoting factors on the cells.

[Induction of chromosome aberrations by the T antigen of the SV40 virus introduced into the cells using liposomes]

A purified SV40 T antigen introduced into hamster cells by means of liposomes accumulated in the nuclei within 10 h and persisted there further as long as 10 to 12 h. Within the first day after cell treatment with T antigen numerous chromosome aberrations including breaks, translocations and gaps were observed in the cells. The number of aberrations slightly reduced by the 2nd day followed by restoration of the normal cell karyotype by the 5th day. Removal of T antigen incorporated into liposomes by a specific immunosorbent or heat inactivation of T antigen abolished the clastogenic effect. It is suggested that induction of chromosome aberrations might activate sell protooncogenes and thus serve a genetic basis of tumor progression.

[Induction of the replicative synthesis of DNA by SV40 virus T antigen introduced into cells using liposomes]

The role of virus SV40 T-antigen in the induction of cell DNA synthesis during its incorporation into cell liposomes was studied, using monolamellar liposomes obtained by phase reversal with incorporated highly purified T-antigen. Immunofluorescence studies revealed that T-antigen effectively penetrates inside the cells and after 10 hours is accumulated in the nuclei, where its level remains unchanged for 24 hours. Injections of purified T-antigen into the renal cells of serum-starved CV1 monkeys resulted in an almost 10-fold increase in the number of DNA-synthesizing cells 18 hours after the exposure. The same effect was observed during stimulation of a 10% serum culture. Removal of T-antigen from the preparation by specific immunoadsorption eliminated this effect. Centrifugation of cells grown in the presence of bromodeoxyuridine in a CsCl gradient was used to demonstrate the replicative type of cell DNA synthesis during T-antigen induction.