An amplitude analysis of the process e+e-→ 4π in the center-of-mass energy range 900–2000 MeV with the CMD3 detector at the VEPP-2000 e+e- collider

A large data sample of e+e-→ 4π collected by the CMD-3 experiment at the VEPP-2000 e+ e− collider allowed for an amplitude analysis of the process e+e−→ 4π in the center-of-mass energy range 900–2000 MeV. Various intermediate components were distinguished and dominance of the ωπ0 and a1π amplitudes has been proved.

Study of the process e+e-→π+π-γ with the CMD-3 detector at the e+e- collider VEPP-2000

Existing Monte-Carlo generators with radiative corrections to the e+e-→π+π- process are usually developed under the assumption that pions can be treated as pointlike particles. We study the e+e-→π+π-γ process with final-state radiation and test this assumption using simulated events from the MCGPJ generator based on the scalar QED hypothesis. In order to increase a fraction of events with FSR, the analysis was performed in the energy region to the left from the ρ-meson peak (660÷785 MeV) that is based on the integrated luminosity of about 8.4 pb-1. The experimental data for the photon energy spectrum agree with the simulation results at 1% level.

Search for the process e+e−→D*(2007) with the CMD-3 detector

A search for the process e+e−→ D*0(2007) has been performed with the CMD-3 detector at the VEPP-2000 e+e−-collider. Two main decay modes of the D*0(2007) decay, D0π0 and D0γ, followed by D0 → K+π−π+π−are used in this analysis. With an integrated luminosity of 3.7 pb−1 collected at the center-of-mass energy Ec.m. =2006.62 MeV our preliminary upper limit is BD*0→e+ e− <1.6× 10−6 at 90%C.L.

Study of π+π−π+π− production with CMD-3 detector at the VEPP-2000 collider

The cross section of the process e+e−→ π+π−π+π− has been measured using an integrated luminosity of 17 pb−1 collected with the CMD-3 detector in the center-of-mass energy range 650-1000 MeV. High-precision measurements of various hadronic cross sections are of great interest in relation with the problem of the muon anomalous magnetic moment g-2. This measurement can be also used to test the relation between the cross section of e+e−→ π+ π−π+ π− and the spectral function for the τ−→ π−π0π0π0 decay predicted by the conservation of vector current (CVC).

Nanocrystalline SiC film thermistors for cryogenic applications

We developed a heat-sensitive material based on nanocrystalline SiC films obtained by direct deposition of carbon and silicon ions onto sapphire substrates. These SiC films can be used for resistance thermometers operating in the 2 K-300 K temperature range. Having high heat sensitivity, they are relatively low sensitive to the magnetic field. The designs of the sensors are presented together with a discussion of their thermometric characteristics and sensitivity to magnetic fields.

[THE IDENTIFICATION OF STENOTPHOMONAS MALTOPHILIA USING THE TECHNIQUES OF DIRECT SEQUENATION 16S P RNA AND MALDI-TOF MASS-SPECTROMETRY]

The in-hospital infections are one of the most serious problems of medicine, especially if patients have a background immunosuppression of various genesis conditioned by both disease itself and corresponding therapy. The detection of presence of infection and identification of agent and detection of its resistance are needed for choosing adequate therapy. At that, high heterogeneity of strains and multiple resistance of nosocomial infections to antibiotics and antimicrobial pharmaceuticals and standardization of antibacterial prevention and number of other causes becomes an obstacle for both determination of medicinal sensitivity of bacterium and for identification of pathogen itself in patient. One of the most complicated in antibacterial therapy pathogens causing pyo-septic diseases, are bacteria Stenotrophomonas spp., the only significant species out of them - Stenotrophomonas maltophilia has primary multiple antibiotic resistance. The significance of early identification of S.maltophilia is obvious. The application of MALDI-ToF mass-spectrometry requires shortage of of time of species identification of primary bacterial culture up to 1-2 hours including sampling preparation and analysis of obtained specters. The sequencing of 16S rRNA requires shortage of of total time od species identification of pathogen from clinical sample (blood) up to 1-12 hours, including sampling preparation ans comparison with successions presented in international data base. The given technique permits to exclude out of analysis prolonged period of obtaining a pure hemoculture of agent. The application of sequencing of 16S rRNA and MALDI-ToF mass-spectrometry as an alternative high-precision techniques shorten time of identification of bacteria, including detection of agent directly in blood of patient. Hence, occurs optimization of complex treatment and shortage of time of selection of adequate therapy that is especially important in case of oncological patients because sensitivity of cultural methods can be diminished due to preventive antibiotics' therapy.

[ZIKA FEVER: CLINICAL, EPIDEMIOLOGICAL, LABORATORY, AND DIAGNOSTIC ASPECTS]

The authors overview data on the prevalence of Zika fever with reference to biological properties of the causative agent, epidemiological process, pathogenesis, and clinical symptoms of the disease. Special attention is given to the identification of the virus in pregnant women, microcephaly in the babies born by Zika-infected women, algorithm of laboratory diagnostics, and measures needed to prevent and control mosquitoes that spread viruses.

[The possibilities for diagnostics of prescription of death coming based on the changes in the lumbar intervertebral disks (the comparison of the morphological, immunohistochemical and topographical findings)]

The objective of the present study was the comprehensive analysis of the postmortem changes in the lumbar intervertebral disks within different periods after death. A total of seven vertebromotor segments were distinguished in the lumbosacral region of the vertebral column based on the examination of 7 corpses. All these segments were divided into three groups in accordance with the prescription of death coming as follows: up to 12 hours (group 1), between 12 and 24 hours (group 2), and between 24 and 36 hours (group 3) after death. The models of the segments thus obtained were subjected to the study by means of diffusion weighted MRI. The removed intervertebral disks were used for morphological and immunohistochemical investigations. The comparison of the diffusion coefficients (DI) revealed the significant difference between the intervertebral disks assigned to groups 1 and 2 (p<0.01). The number of the cells in the pulpal core, the vertebral end plate, and the fibrous ring in all the above groups of the intervertebral disks was significantly reduced (p<0.01). The analysis of the correlation dependence between cell density and diffusion coefficients has demonstrated the well apparent relationship between these characteristics of the intervertebral disks comprising groups 1 and 2. It is concluded that diffusion weighted MRI in the combination with the calculation of diffusion coefficients for the intervertebral disks provides a tool for diagnostics of prescription of death coming as confirmed by the results of the morphometric studies and immunohistochemical analysis.

Superconductivity in highly disordered NbN nanowires

The topic of superconductivity in strongly disordered materials has attracted significant attention. These materials appear to be rather promising for fabrication of various nanoscale devices such as bolometers and transition edge sensors of electromagnetic radiation. The vividly debated subject of intrinsic spatial inhomogeneity responsible for the non-Bardeen-Cooper-Schrieffer relation between the superconducting gap and the pairing potential is crucial both for understanding the fundamental issues of superconductivity in highly disordered superconductors, and for the operation of corresponding nanoelectronic devices. Here we report an experimental study of the electron transport properties of narrow NbN nanowires with effective cross sections of the order of the debated inhomogeneity scales. The temperature dependence of the critical current follows the textbook Ginzburg-Landau prediction for the quasi-one-dimensional superconducting channel I _c ∼ (1-T/T _c)^3/2. We find that conventional models based on the the phase slip mechanism provide reasonable fits for the shape of R(T) transitions. Better agreement with R(T) data can be achieved assuming the existence of short 'weak links' with slightly reduced local critical temperature T _c. Hence, one may conclude that an 'exotic' intrinsic electronic inhomogeneity either does not exist in our structures, or, if it does exist, it does not affect their resistive state properties, or does not provide any specific impact distinguishable from conventional weak links.

HBV COVALENTLY CLOSED CIRCULAR DNA AS A MARKER OF PREVALENCE OF OCCULT HEPATITIS В IN PATIENTS WITH HBV, HDV AND HCV INFECTION IN UZBEKISTAN

Aim. Evaluate significance of covalently closed circular DNA of hepatitis В virus as a marker for detection of occult viral hepatitis В in Uzbekistan population with hepatitis of various genesis. Materials and methods. Blood plasma and liver biopsy from 39 patients with different severity levels of liver fibrosis and cirrhosis served as study material. HBV covalently closed circular DNA detection was carried out according to Pollicino T. et al. (2004). Results. Covalently closed circular DNA of hepatitis В virus was detected in 82% of samples, including in 54.5% of patients with chronic viral hepatitis C (CVHC) and in 100% of patients with hepatitis of unknown etiology. Quantitative evaluation of content of covalently closed circular DNA of hepatitis В virus in liver tissue in patients with CVHB has shown an average of 2.5 copies of HBV genome as ccc DNA per cell, in patients with CVHB + D an average of 0.7 copies/cell, in patients with co-infection by HCV and HBV - 0.5 copies/cell, in patients with CVHC an average of 0.12 copies/cell, and in patients with cryptogenic hepatitis - 0.2 copies/cell. Conclusion. Detection of HBV DNA is a complex problem for effective laboratory diagnostics of hepatitis. Detection of H BV ccc DNA as a marker of occult hepatitis В in patients with CVHC and patients with hepatitis of unclear etiology is an important factor for diagnostics, selection of adequate therapy, prognosis of disease outcome and prevention of development of severe liver diseases.

MOLECULAR-BIOLOGICAL MARKERS OF HEPATITIS В IN PATIENTS WITH LIVER FIBROSIS/CIRRHOSIS IN UZBEKISTAN

Aim. Evaluate prevalence of genetic variants of hepatitis В viruses in population of various regions of Uzbekistan with hepatitis of various genesis and different severity levels of liver fibrosis and cirrhosis. Materials and methods. Blood plasma and liver biopsy from 39 patients with different severity levels of liver fibrosis and cirrhosis served as study material. Genotyping based on direct sequencing of Pre-Sl/Pre-S2/S HBV DNA region was applied. Results. Hepatitis В virus was detected in 32 samples ofthe 39 provided, frequency of occurrence - 82%, respectively. Phylogenetic analysis has shown, that only genotype D was detected among the examined patients, hepatitis В virus subtype D1 predominated (84.38%) compared with D2 (3.12%) and D3 (12.5%) subtypes. Conclusion. Large-scale sequencing of HBV in Central Asia will allow to evaluate routes of transmission and time of evolutionary separation of virus isolates. Understanding the epidemiology of the infectious process is important for development of programs for prophylaxis and therapy of the infection.

Dose-Response of Micronuclei in Binucleated and Mononucleated Lymphocytes from Cytochalasin Culture (Irradiation in vivo and in vitro)

The dose-responses of micronuclei (MN) in binucleated (BN) and mononucleated (MONO) lymphocytes cultivated with cytochalasin B (CBMN-assay) were studied. Irradiation of lymphocytes was performed in vitro (donor A) at the single dose of 1 and 2 Gy of (60)Co y-rays, or in vivo, during whole-body exposure of a cancer patient (donor B) to (60)Co γ-rays each day at a single dose of 0.115 Gy up to a total dose of 1.15 Gy. The linear dose-response for MN was determined in both BN and MONO lymphocytes of donor B. It means that when CBMN assay is applied, the MN in MONO cells represent those preexisted in vivo before each exposure. On the contrary, in lymphocytes of donor A irradiated in vitro an essential elevated MN yield with an - increased dose was observed only in BN lymphocytes. A slight dose dependent elevation of MN in MONO cells seems to be due to either their division before cytochalasin was introduced in the culture medium or their insensitivity to the CB block of cytokinesis.

[MOLECULAR-BIOLOGICAL MARKERS OF HEPATITIS B IN PATIENTS WITH LIVER FIBROSIS/CIRRHOSIS IN UZBEKISTAN]

AIM

Evaluate prevalence of genetic variants of hepatitis B, viruses in population of various regions of Uzbekistan with hepatitis of various genesis and different severity levels of liver fibrosis and cirrhosis.

MATERIALS AND METHODS

Blood plasma and liverbiopsy from 39 patients with different severity levels of liver fibrosis and cirrhosis served as study material. Genotyping based on direct sequencing of Pre-S1/Pre-S2/S HBV DNAregion was applied.

RESULTS

Hepatitis B virus was detected in 32 samples ofthe 39 provided, frequency of occurrence - 82%, respectively. Phylogenetic analysis has shown, that only genotype D was detected among the examined,patients, hepatitis B virus subtype D1 predominated (84.38%) compared with D2 (3.12%) and.D3 (12.5%) subtypes.

CONCLUSION

Large-scale sequencing of HBV in, Central Asia will allow to evaluate routes of transmission and time of evolutionary separation or virus isolates. Understanding the epidemiology of the infectious process is important for development of programs for prophylaxis and therapy of the infection.

[HBV COVALENTLY CLOSED CIRCULAR DNA AS A MARKER OF PREVALENCE OF OCCULT HEPATITIS B IN PATIENTS WITH HBV, HDVAND HCV INFECTION IN UZBEKISTAN]

AIM

Evaluate significance of covalently closed circular DNA of hepatitis B virus as a marker for detection of occult viral hepatitis B in Uzbekistan population with hepatitis of various genesis.

MATERIALS AND METHODS

Blood plasma and liver biopsy from 39 patients with different severity levels of liver fibrosis and cirrhosis served as study material. HBV covalently closed circular DNA detection was carried out according to Pollicino T et al. (2004).

RESULTS

Covalently closed circu- lar DNA of hepatitis B virus was detected in 82% of samples, including in 54.5% of patients with chronic viral hepatitis C (CVHC) and in 100% of patients with hepatitis of unknown etiology. Quantitative evaluation of content of covalently closed circular DNA of hepatitis B virus in liver tissue in patients with CVHB has shown an average of 2.5 copies of HBV genome as ccc DNA per cell, in patients with CVHB + D an average of 0.7 copies/cell, in patients with co-infection by HCV and HBV - 0.5 copies/cell, in patients with CVHC an average of 0.12 copies/cell, and in patients with cryptogenic hepatitis - 0.2 copies/cell.

CONCLUSION

Detection of HBV DNA is a complex problem for effective laboratory diagnostics of hepatitis. Detection of HBV ccc DNA as a marker of occult hepatitis B in patients with CVHC and patients with hepatitis of unclear etiol- ogy is an. important factor for diagnostics, selection of adequate therapy, prognosis of disease outcome and prevention of development of severe liver diseases.

Coherent Excited States in Superconductors due to a Microwave Field

We describe theoretically the depairing effect of a microwave field on diffusive s-wave superconductors. The ground state of the superconductor is altered qualitatively in analogy to the depairing due to a dc current. In contrast to dc depairing, the density of states acquires, for microwaves with frequency ω_{0}, steps at multiples of the photon energy Δ±nℏω_{0} and shows an exponential-like tail in the subgap regime. We show that this ac depairing explains the measured frequency shift of a superconducting resonator with microwave power at low temperatures.

[Zika virus infection: clinical and diagnostic aspects and organization of preventive measures]

The article presents modem data about Zika virus outbreak, the biological characteristics of the pathogen, vectors, the nature of the epidemic process, pathogenesis and diagnosis of infection. This infection has a high potential for epidemic spread because vectors are widely represented in the fauna of many climatic and geographic zones. It presents information on the main clinical manifestations of the disease. Particular attention is paid to the problem of congenital maiformations of the nervous system (microcephaly and others) detected in infants born to women infected with Zika virus. The basis of therapy in this disease constitute a pathogenic agent. The'package of, measures for the prevention of disease caused by Zika virus, including early identification and treatment of patients, as well as measures for the destruction of the virus vectors.

[TYPING OF LEPTOSPIRA SPP. STRAINS BASED ON 16S rRNA]

AIM

Comparative typing of Leptospira spp. strain collection based on analysis of 16S RNA fragment.

MATERIALS AND METHODS

2 pairs of primers were used for PCR, that jointly flank 1423b.p. sized fragment. Sequences of Leptospira spp. strain 16S rRNA, presented in the international database, were used for phylogenetic analysis.

RESULTS

A high similarity, including interspecies, of the 16S fragment in Leptospira spp. strains was shown independently of the source, serovar and serogroup. Heterogeneity of the primary matrix, spontaneous mutations of hotspots and erroneous nucleotide couplings, characteristic for 16S sequence of pathogenic Leptospira spp. strains, are discussed. Molecular-genetic characteristic of certain reference Leptospira spp. strains by 16S sequence is obtained.

CONCLUSION

Results of the studies give evidence on expedience of introduction into clinical practice of identification of Leptospira spp. by 16S sequence directly from the clinical material, that would allow to significantly reduce identification time, dismiss complex type-specific sera and other labor-intensive methods.

[Frequency of chromosomal aberrations in lymphocytes of peripheral blood in patients with solid tumors]

There was carried out a study to compare the frequency of spontaneous chromosomal aberrations (CA) in lymphocytes of peripheral blood between the group of cancer patients with different types of solid tumors and the group of healthy people of the same age. There was established a significant increase in the average frequency of CA in cancer patients. Analysis of the group of patients has revealed its heterogeneity: in the majority of patients the individual frequency of CA significantly exceeded the average frequency of CA in the control group, in some - did not differ from that. The first patients were described as the group with "generalized" genomic instability. Also this group differed by increased radiosensitivity of lymphocyte chromosomes during their irradiation in vivo.

Analysis of Populations of Memory T-Helper Cells Expressing CXCR3 and CCR6 Chemokine Receptors in Peripheral Blood of Patients with Chronic Viral Hepatitis C

Flow cytometry was employed to examine the content of major populations of memory T helper cells and expression of chemokine receptors CXCR3 and CCR6 on their surface in peripheral blood drawn from virtually healthy people and the patients with chronic viral hepatitis C. The following combination of monoclonal antibodies had been used: CD62LFITC/CD45RA-PE/CD3-ECD/CCR6-PC7/CXCR3-APC/CD4-APC-Cy7. In comparison with control group, the patients with chronic hepatitis C had a smaller number of populations of naïve CD4(+) T cells and central memory CD4(+) T cells but a greater number of terminally differentiated effector memory CD4(+) T cells and effector memory CD4(+) T cells. No differences were revealed between CD4(+) T cell populations of both groups in expression of CXCR3 and CCR6 receptors.

[PRODUCTION OF CERTAIN PRO- AND ANTI-INFLAMMATORY CYTOKINES DURING STIMULATION BY LIVE AND INACTIVATED LEPTOSPIRA PATHOGENS IN THE MODEL OF HUMAN WHOLE BLOOD]

AIM

Study of the ability of clinical isolates of leptospira to cause production of certain pro- and antiinflammatory cytokines in the model of human whole blood.

MATERIALS AND METHODS

Leptospira interrogans strain was taken for the experiment. Cytokine content was determined by a method based on xMAP technology using a standard panel, composed of 9 analytes: TNF-α, MCP-1, IL-8, IL-4, IL-6, IL-10, IL-IRa, IL- 12 (p70), IFN-γ.

RESULTS

An optimal concentration of L. interrogans was selected for stimulation of human whole blood--1 x 10(6) leptospirae/ml. For the first time in the model of human whole blood it was determined, that at early stages of incubation IFN-γ, IL-12(p70), IL-4 and IL-1Ra are more actively produced; at later stages (6 hour incubation)--IL-8 and TNF-α.

CONCLUSION

A differential pattern of cytokine production stimulation was shown in the model of human whole blood by live and inactivated leptospirae.