Oxygen surface exchange kinetics of Ba0.5Sr0.5Co0.8Fe0.2O3-δ.

The mechanism of oxygen exchange between the gas phase and Ba0.5Sr0.5Co0.8Fe0.2O3-δ oxide was evaluated by considering the inhomogeneity of the oxide surface. The applicability of existing models for the analysis of the oxygen exchange mechanism was considered. A new model with a dissociation step was suggested. The rate-determining steps of the oxygen exchange process were revealed under different experimental conditions. The change in the rate-determining step occurred at 600-650 °C. The probable cause was considered taking into account the parameter of nonequivalency of adsorption centers. A relationship between the oxygen isotope redistribution rates and the rates of the elementary steps in a "gas phase-solid oxide" system was revealed.

[Impact of waste landfills in the Saratov region on the sanitary condition of the soil].

Monitoring of environment in regions of the location of waste landfills includes the implementation of the control over a sanitary condition of soils. The main origins of the spread ofpollutants into soils are the solid particles from aerosol emissions from the functioning of landfills transmitted to surrounding territories. Within zones of the impact of three largest waste landfills in the Saratov region (Aleksandrovsky, Guselsky in the city of Saratov and Balakovsky in the city of Balakovo) there were taken 152 soil samples. According to results of the estimation in soil concentration of gross and motile forms of heavy metals of the first (Zn, Cd, Ni) and the second danger classes (Cu, Cr, Pb) there was performed the analysis of coefficients of danger- K0 and total coefficients ofpollution - Zc. There was executed the assessment of both a sanitary and hygienic condition of soils and degree of danger ofpollution. The most contrast areal features of the distribution of the danger coefficient - Ko in soils are characteristic for motile forms of heavy metals. For all three studied objects persistently there is stood out the dangerous and areal pollution of soils by association of Ni and Cu . The danger ofpollution of soils by gross forms of heavy metals is minimum. The coefficient of total pollution of Zc exceeds admissible level on motile forms of heavy metals only for the soils surrounding the Balakovo landfill. In zones of the impact of waste landfills there are located the processed lands with an adverse sanitary and hygienic condition of soils. In the region of the Guselsky object soils of the processed agricultural grounds are dangerously polluted by motile forms of Ni and Cu. In vicinities of the Balakovo waste landfill considerable areas of private gardening enterprises are dangerously polluted by the motile forms of Ni, Cu and Zn.

Oxygen isotope exchange in La2NiO(4±Î´).

Oxygen surface exchange kinetics and diffusion have been studied by the isotope exchange method with gas phase equilibration using a static circulation experimental rig in the temperature range of 600-800 °C and oxygen pressure range of 0.13-2.5 kPa. A novel model which takes into account distributions of the dissociative adsorption and incorporation rates has been developed. The rates of the elementary stages have been calculated. The rate-determining stages for a La2NiO(4±Î´) polycrystalline specimen have been discussed. The diffusion activation energies calculated using the gas phase equilibration method (1.4 eV) differ significantly from those calculated using isotope exchange depth profiling (0.5-0.8 eV), which was attributed to the influence of different oxygen diffusion pathways.

Luminosity-independent measurement of the proton-proton total cross section at √s=8 TeV.

The TOTEM collaboration has measured the proton-proton total cross section at √s=8 TeV using a luminosity-independent method. In LHC fills with dedicated beam optics, the Roman pots have been inserted very close to the beam allowing the detection of ~90% of the nuclear elastic scattering events. Simultaneously the inelastic scattering rate has been measured by the T1 and T2 telescopes. By applying the optical theorem, the total proton-proton cross section of (101.7±2.9) mb has been determined, well in agreement with the extrapolation from lower energies. This method also allows one to derive the luminosity-independent elastic and inelastic cross sections: σ(el)=(27.1±1.4) mb; σ(inel)=(74.7±1.7) mb.

Double diffractive cross-section measurement in the forward region at the LHC.

The first double diffractive cross-section measurement in the very forward region has been carried out by the TOTEM experiment at the LHC with a center-of-mass energy of sqrt[s]=7 TeV. By utilizing the very forward TOTEM tracking detectors T1 and T2, which extend up to |η|=6.5, a clean sample of double diffractive pp events was extracted. From these events, we determined the cross section σDD=(116±25) µb for events where both diffractive systems have 4.7<|η|min<6.5.

[Synthesis and biological activity of 2,3-secotriterpene acid mono- and diamides].

Four types of amide (C3; C28; C3-C28) conjugates based on 2,3-seco-18alphaH-oleanane and 2,3-secolupane mono- and dicarboxylic acids were synthesized. The range of diamide derivatives was supplemented with C3-C3' and C28-C28' dicondensed amides with two A-secotriterpene backbones educed by reacting monocarboxylic A-secoacids with biogenic amino acid lysine. Compounds with inhibitory action against herpes virus reproduction (EC50 8.7 and 4.1 McM) were found among the synthesized mono- and diamide derivatives containing an ethyl-beta-alaninate fragment. It has been ascertained that diamide with ethyl-beta-alaninate fragment combines anti-herpes virus properties and anti-HIV activity (EC50 5.1 McM). For active compounds, the maximum non-toxic concentration (MNTC)/EC50 ratios ranges from 9.7 to 40.8. The synthesized amide conjugates do not exhibit any marked cytotoxic effects against human tumor cell lines rabdomiosarcoma RD TE32, A549 lung carcinoma and melanoma MS.

[New method for calculating the dissipation parameters in ultrafast biochemical reactions from protein crystal structure data].

A new method of calculating the spectral function of system-bath interaction during elementary biochemical reaction is proposed. This method was applied to the primary electron transfer in the photosynthetic reaction center of purple bacteria Rh. Sphaeroides. The calculated spectral functions differ significantly from the commonly used ohmic function. It is shown that the unidirectionality of the electron transfer along the A-branch in the reaction center of Rh. Sphaeroides can be caused by the asymmetry or reaction system interaction with the protein environment.

[A new unique HIV-1 recombinant form detected in Belarus].

Republican Research-and-Practical Center for Epidemiology and Microbiology, Ministry of Health of Belarus, Minsk The paper presents data on the molecular genetic characteristics of a new HIV-1 recombinant form. The study has shown that the virus is referred to as HIV-1 subtype B in terms of the gag gene and HIV-1 subtype A in terms of the pol and env genes. At the same time the new isolate is closer, in terms of the gag gene, to the HIV-1 DQ207943 strain isolated in Georgia, in terms of the pol gene, to the HIV-1 AF413987.1 strain isolated in Ukraine and, in terms of the env gene to the HIV-1 AY500393 strain isolated in Russia. Thus, the described new HIV-1 recombinant form has the following structure: BgagApolAenv. The gag, pol, and env gene sequences from the new unique HIV-1 recombinant form have been registered in the international database EMBL/Genbank/DDBJ under accession numbers FR775442.1, FN995656.1, and FR775443.1.

[Molecular epidemiology of genital papillomavirus infection in the Republic of Belarus].

AIM: Determination of epidemiologic features of genital HPV infection in women living in the Republic of Belarus, and detection of phylogenetic features of HPV-16. MATERIALS AND METHODS: 1035 samples of epithelial cervix smears from patients with benign pathology, pre-cancer and cervix cancer were included into the study. 35 samples containing HPV-16 type DNAwere selected for sequencing. HPV L1 gene sequencing (300 n.p.) was performed by using 3100-Avant (Applied Biosystems). Sequencing results analysis was performed by using ClustalX (1.8) and BioEdit. MEGA 4.1 was used for phylogenetic analysis of the fragments obtained and tree construction. RESULTS: HPV-16 type is a dominant genotype that is responsible for the development of cervix cancer, its frequency of occurrence is 56.7% among patients with the specified pathology living in the Republic of Belarus. Predominance of East-Asian and European HPV-16 subtypes that can be attributed to a single evolutionary branch are the territorial features. At the same time detection of HPV-16 subtypes that have 0.003 - 0.007 p-distance between probes may indicate the presence of the several progenitors circulating in the country. A unique HPV-16 subtype was sequenced in the Gomel Region that could be one of the progenitors of HPV-16 circulating on the European continent. CONCLUSION: Further studies performed in the field of molecular epidemiology will allow to give a qualitative characteristic of the epidemic process, determine the direction and time of introduction of the virus into the country, control the circulation of the virus in the population.

[Prevalence of high- and low-risk oncogenic human papillomaviruses in patients with external genital pathology].

The paper presents the results of examining 49 patients with genital papillomas, vulvar and vaginal leukoplakia, dysplasia, and cancer. The findings may suggest that human papillomavirus plays an important role in the development of vulvar and vaginal lesions and reconsider the importance of high- and low-risk oncogenic genotypes in the development of benign neoplasms, precancerous conditions, and malignant tumors of the vulva and vagina.

[The molecular epidemiology of HIV-1 in Belarus in (1996-2004): a predominance of subtype A variants and circulation of subtype B variants].

To study the molecular epidemiology of HIV-1 in Belarus, the genetic sequences of HIV-1 variants were obtained from 50 infected persons, which represented the main stages, risk groups, and geographic areas of the epidemic. The env and gag sequences were studied for HIV-1 variants from 31 persons, the env sequences were for HIV-1 variants from 18 persons, and the gag sequence was for HIV-1 variant from 1 person. Phylogenetic analysis indicated that the sequences of HIV-1 variants from 46 persons were homogenic and evolutionally closely related to IDU-A strains specific for other epidemics in the former Soviet Union are dominating in the epidemic in Belarus. Circulation of epidemiologically unrelated subtype B viruses was also established.

Accumulation of transcripts coding for prion protein in human astrocytes during infection with human immunodeficiency virus.

The abnormal isoforms of the normal cellular prion protein (PrP), also termed Scrapie-associated fibril protein, are assumed to be one causative factor of spongiform encephalopathies. The mRNA of PrP contains stem-loop structures which are very similar to the human immunodeficiency virus-1 (HIV-1) cis-acting sequence TAR within the LTR; both structures contain the pentanucleotide CUGGG in the loop, and the uridine- and adenine-bulge in the stem. In this study, using purified HIV-encoded trans-activator, Tat, and HIV-1 TAR-RNA or PrP-mRNA containing the stem-loop structure, we demonstrate by use of gel-retardation and filter binding assays that Tat binds to TAR- and PrP-RNA with the dissociation constants of 2.9 or 37.0 nM, respectively, at a molar ratio of 0.7 mol of Tat to 1 mol of RNA fragment. The Tat-RNA (TAR or PrP) complexes bind to protein(s) in the nuclear matrix, isolated from human astrocytes (glial fibrillary acidic protein positive brain cells). Infection of astrocytes with HIV-1 resulted in an increased level of PrP mRNA. The data presented led us to assume that certain sequences in the PrP mRNA might be targets for proteins acting in trans.

[Somatotype of women of the Stavropol region with mammary gland pathology].

The aim of this study was to determine the somatotypic characteristics of women living in Stavropol region, both healthy persons and patients with mammary cancer. 105 women of second period of mature age and of eldery age were examined. For somatotype assessment the scheme of V.P. Chtetzov et al. (1979) was used. Age peculiarities of morphological typing were demonstrated that revealed the dominance of athletic type in mature age and mesoplastic type in the elderly one. The analysis of anthropometric parameters of women with oncological pathology in the indicated periods of ontogenesis has demonstrated a predominance of a mesomorphic vector in shaping their somatotype. The marker signs possessing the greatest informative value in mammary cancer patients of a second period of mature age were the low values of thickness of brachial and breast adipose folds. These signs are suggested as criteria for the formation of groups of risk.

Susceptibility of primary human glial fibrillary acidic protein-positive brain cells to human immunodeficiency virus infection in vitro: anti-HIV activity of memantine.

Primary human glial fibrillary acidic protein-positive (GFAP+) brain cells (enriched population) have successfully been infected with human immunodeficiency virus type 1 (HIV-1) in vitro, when cocultivated with HIV-1-producing H9 cells. Direct incubation of brain cells with HIV-1 resulted only in a limited infection. The percentage of HIV+ cells increased from 5% in passage 1 to 40% in passage 8. Simultaneously with the increase of infected cells, the reverse transcriptase activity in the culture medium increased and reached maximal values in passage 8. The infected cells also produced intact viral particles. In the early phase of cultivation the HIV-infected cells displayed a significantly higher proliferation rate than the uninfected controls. At passage number 8 the HIV-infected GFAP+ cells had almost totally lost the ability to grow, while the controls proliferated at a rate almost unimpaired from the beginning of the cultivation. Up to 10 to 15% of the HIV-infected GFAP+ cells contained at passage number 5 more than 3 nuclei. Memantine (1-amino-3,5-dimethyladamantane), a blocker of the N-methyl-D-aspartate receptor channels, was found to display a significant anti-HIV effect (at a concentration of 1 microgram/ml) on enriched cultures of GFAP+ cells in vitro.

[Structural organization and intravirion interactions of proteins of the bovine leukemia virus]. / Strukturnaia organizatsiia i vnutrivirionnye vzaimodeistviia belkov virusa leikoza krupnogo rogatogo skota.

Data on structural organization and interactions inside the virion of bovine leukemia virus (BLV) proteins are presented. Uniqueness of the structural organization of BLV proteins having no antigenic relationship between the corresponding animal retrovirus proteins is emphasized. Certain connection is also observed in the structural organization of surface glycoprotein gp69, major internal protein p24 and internal protein p12 with the corresponding polypeptides of human T-cell leukemia virus (HTLV). It is shown that BLV proteins form various complexes inside the virion which are not found in other known retroviruses. A structural model of BLV is presented.

[Synthesis and antiviral activity of amides and conjugates of betulonic acid with amino acids]. / Sintez i protivovirusnaia aktivnost' amidov i kon''iugatov betulonovoi kisloty s aminokislotami.

Betulonic acid amides with aliphatic and heterocyclic amines and with L-amino acids were synthesized by the acid chloride method. Betulonic acid amide and L-methionine derivatives of betulonic acid and its 3-oxime effectively inhibit the influenza A virus. Betulonic acid octadecylamide is active against the herpes simplex type 1 virus. The conjugate of betulonic acid 3-oxime with L-methionine is also active toward HIV-1. The tested compounds mainly show no activity toward the ECHO6 virus, which is devoid of a coat. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 1; see also http://www.maik.ru.

[Synthesis and antiviral activity of hydrazides and substituted benzalhydrazides of betulinic acid and its derivatives]. / Sintez i protivovirusnaia aktivnost' gidrazidov i zameshchennykh benzal'gidrazidov betulinovoi kisloty i ee proizvodnykh.

New nitrogen-containing derivatives of betulinic and betulonic acids, hydrazides and N'-benzalhydrazides, were synthesized. Their antiviral activities toward of influenza A virus, herpes simplex type I virus, enterovirus ECHO6, and HIV-1 were studied in vitro. Betulinic acid 3-oxime was found to have the highest activity against the influenza virus. Betulonic acid, betulinic acid 4-chlorobenzalhydrazide, betulonic acid 3-oxime benzalhydrazide, and betulinic acid hydrazide inhibited the replication of herpes simplex type I virus. Betulinic acid hydrazide also showed antiviral activity toward HIV-1. All the derivatives of betulinic acid under study displayed a low antiviral activity toward enterovirus ECHO6.

Viral water contamination as the cause of aseptic meningitis outbreak in Belarus.

In the recent years Echovirus-30 associated outbreaks have taken place in different European countries. Aseptic meningitis caused by Echovirus-30 was the main diagnosis of a large outbreak in Belarus in Summer-Autumn, 1997, involving 460 patients. Echovirus-30 was detected in cerebrospinal fluid of the patients with aseptic meningitis. This serotype played the dominant role in the outbreak. Minor serotypes and mixtures of enteroviruses were detected in faeces and nasopharyngeal lavages. Investigation of environmental samples gave evidence of expressed viral contamination of drinking water and water sources (river and ground sources). River water sources were considerably contaminated with viruses. The incidence of virus isolation was 50%. After cleaning procedures, the incidence became two times lower, proving imperfect water purification and disinfection procedures. Sequence analysis of isolates from Belarus (isolates from water and patient's cerebrospinal fluid) showed the difference of 0.2%. The outbreak peculiarities such as high attack rate and wide-spread of the disease incidences, clinical form variability, isolation of outbreak strain from water and a good agreement between minor serotypes isolated from faeces and water samples as well as correlation in the dynamics of acute intestine infections, aseptic meningitis morbidity and bacterial water contamination can be considered as evidence of its water-borne. Echovirus-30 isolates from Belarus were very closely related to each other and to several European isolates. Sequence difference between isolates of 1994-1998 from European countries was found to be 4.3%. The data can point to the common primary source of enterovirus infection, connected to water and to the possibility of epidemic strain transmission from neighbouring states to the Republic of Belarus.

[Phenotypic characteristics of HIV isolates, isolated in the Belarus Republic]. / Fenotipicheskaia kharakteristika izoliatov VICh, vyiavlennykh na territorii respubliki Belarus'.

Biological characteristics of 26 HIV strains circulating in the Republic of Belarus were studied in cell cultures. By the replicative activity, infectivity, and tropism to certain cell lines, all the strains can be divided into 2 groups: rapid/high and slow/low. Slow/low HIV strains were isolated from asymptomatic patients with lymphadenopathy and from AIDS patients. On the other hand, two rapid/high strains were isolated from patients without clinical signs of AIDS 6-8 months after probable infection.