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At least 109 records · Page 6Linked to original sources
PubMed2004

High-order harmonic generation up to 250 eV from highly ionized argon.

We demonstrate the generation of very high-order harmonics, up to 250 eV, using argon gas. This extends by 100 eV the highest harmonics previously observed using Ar and exceeds the energies observed using any other medium besides helium. This advance is made possible by using a waveguide geometry to limit plasma-induced laser beam defocusing, making it possible to generate high harmonics from Ar ions. This work shows that high harmonic emission from ions can extend laser-based coherent up-conversion into the soft x-ray region of the spectrum.

Journal Article↗
PubMed2006

Scattering of 64 eV to 3 keV neutrons from polyethylene and graphite and the coherence length problem.

We measured the neutron scattering intensity ratios from polyethylene (CH2) relative to graphite (C) at several discrete final energies, of narrow widths (approximately 3 eV) between 64 eV and 3 keV. The final energies were selected using a 238U filter. This experiment was carried out to search for any anomaly in the n-p scattered intensities from CH2 caused by the neutron coherence length. The scattered intensity ratios were found to conform to conventional expectations and no anomaly was observed.

Journal Article↗
PubMed1979

Characterization of EV-2, a Virus Isolated from European Eels (Anguilla anguilla) with Stomatopapilloma.

A virus designated EV-2 has been isolated from external tumor tissue and internal organs of European eels (Anguilla anguilla) with stomatopapilloma. It contains RNA and is ether, acid, and temperature labile above 4 degrees C, and concentrated preparations agglutinate chicken and sheep erythrocytes. The addition of actinomycin D during the first 2.75 h of infection inhibits viral replication. As determined in sucrose gradients, the buoyant density of the virus is 1.19 g/cm(3). EV-2 has a moderately pleomorphic spherical morphology; its diameter ranges from 80 to 140 nm. The virion has narrow, regularly spaced surface projections about 10 nm long. Replication in FHM cells at 15 degrees C shows new infectivity appearing at 10 h postinfection and reaching a plateau at 20 h. Cytopathic effects consist of cell fusion, syncytia, and irregularly rounded cell masses. Viral antigen was detected in the cytoplasm of infected cells by specific immunofluorescence.

Journal Article↗
PubMed1986

Molecular cloning and characterization of gag-, pol-, and env-related gene sequences in the ev- chicken.

Using less stringent hybridization conditions and cloned viral DNA probes representing the avian sarcoma virus gag, pol, env, and long terminal repeat (LTR) gene sequences, we detected related sequences in two avian species purportedly lacking all endogenous avian leukosis viruses, the ev- chicken and the Japanese quail. The blot hybridization patterns obtained with the various probes suggest the presence of between 40 and 100 copies of retrovirus-related sequences in the genomes of these two species. An ev- chicken genomic DNA library was prepared and screened with gag-specific and pol-specific DNA probes. Several different clones were obtained from this library and characterized. Analysis of these clones revealed that the retrovirus-related gene sequences are linked in the order LTR-gag-pol-env-LTR, a structure indicative of a complete provirus. These data indicate the presence of previously unidentified endogenous retrovirus species in avian cells, suggesting that under the appropriate conditions of hybridization additional, more distantly evolved families of endogenous retrovirus genes may be identified in vertebrate species.

Animals↗
PubMed2000

Damage induced by 1-30 eV electrons on thymine- and bromouracil-substituted oligonucleotides.

The impact of low-energy (1-30 eV) electrons on self-assembled monolayers of heterogeneous oligonucleotides chemisorbed on a gold surface has been investigated by mass spectrometry of desorbed neutral species in an attempt to understand the consequences of secondary electron damage in a short sequence of a DNA single strand. We demonstrate that the most intense observable neutral species (CN, OCN and/or H(2)NCN) desorbed from Cy(6)-Th(3) and Cy(6)-(BrdU)(3) oligos are related to primary fragmentation of the bases induced by electron impact. The dependence of the neutral species desorption on electron energy shows typical signatures of dissociative electron attachment initiated by the formation of shape- and core-excited resonances (i.e. single-electron and two-electron- one-hole transitory anions, respectively). Substitution of dTh by BrdU increases the production of neutral fragments by as much as a factor of about 3 for the entire electron energy range. When the distribution of secondary electrons along radiation tracks in H(2)O is taken into account, we show that the probability for electron damage to heterogeneous oligonucleotides is enhanced by a factor of 2.5-3 for electron energies below 20 eV for both sensitized and unsensitized strands.

Bromouracil↗
PubMed2003

Alteration of protein constituents induced by low-energy (<35 eV) electrons: II. Dissociative electron attachment to amino acids containing cyclic groups.

We report measurements of the desorption of anions from thin condensed films of tryptophan (Trp), histidine (His) and proline (Pro) stimulated by 5-35 eV electron impact. H-, O-, OH- and CN- desorb from Trp, His and Pro, whereas CH2- is observed only from Pro fragmentation. Below 12 eV, the anion yield functions exhibit resonant structures indicative of dissociative electron attachment. For all three amino acids, this process is likely to be initiated by the resonant capture of the incident electron at the NH3(+)-CH-.....-COO- and/or NH2-CH-.....-COOH group of the molecule. Temporary electron attachment to the ring leads to anion desorption only for tryptophan and proline. The energy-averaged yields measured at the detector of the mass spectrometer are (4.9, 0.3 and 54.0) x 10(-8) H-/incident electron and (3.4, 2.9, 1.8) x 10(-11) O-/incident electron, respectively, from Trp, His and Pro dissociation. Fragmentation of amino acids is found to be as intense as that of the nucleic acid bases. These results are discussed within the context of radiobiological damage induced by secondary electrons.

Amino Acids↗
PubMed1995

Characterization of eight endogenous viral (ev) genes of meat chickens in semi-congenic lines.

Restriction fragment length polymorphism analysis was conducted for a set of eight different meat chicken-derived endogenous viral genes (ev genes) of the avian leukosis viral (ALV) family. Each viral element was first isolated into a separate single-element line by selective breeding. Genomic DNA from the founder male for each semi-congenic, single-element line was digested with each of four restriction enzymes, and the resulting Southern blots were each hybridized with up to four probes representing different portions of the ALV retroviral genome. Among the eight elements, there was one that represents the broiler equivalent of locus ev3 of White Leghorn chickens. A second broiler element showed a SacI-specific junction fragment similar to that of ev8. The remainder appeared to be different from any of the 21 ev genes previously described for White Leghorn chickens. Four of the eight elements examined were essentially complete, but the rest have sustained internal deletions.

Alpharetrovirus↗
PubMedDate not supplied

[The properties of the cellular surface of Yersinia pestis strain EV and its achromogenic variants].

The comparative study of the properties of the surface of vaccine strain Y. pestis EV and its achromogenic variants (AV) differing from the initial strain by decreased immunogenicity and by the morphology of colonies, has been made. The achromogenicity of Y. pestis colonies has been shown to correlate with the loss of the outer membrane protein with a molecular weight 22 kD. The synthesis of this protein is determined by chromosomal genes. AV have been found to have different sensitivity to bacteriophages. The analysis of the electrokinetic potential of Y. pestis EV and its AV has revealed that in the latter have surface charge is considerably greater (1.4- to 1.5-fold). As shown in this study, the hemagglutinating activity of AV with respect to red blood cells of humans with blood group I (O) and guinea pigs is decreased by 1-2 orders and these strains do not agglutinate with sheep red blood cells. The low activity of the initial stage of the phagocytosis of AV by mouse macrophages has been shown. The possible role of the 22 kD proteins as an adhesion factor is discussed.

Animals↗
PubMed2002

[Effect of monokines induced by Yersinia pestis EV on the functional activity of neutrophils during development of antiplague immunity].

A study was made of the Yersinia pestis EV induced monokine complex influence on neutrophil (Nph) functional activity in the course of antiplague immunity formation. The obtained monokines essentially enhance Nph killing, chemotactic activities and Fc-receptor expression, and stimulate lysosome membrane labilization of these cells. The helper effect of the Y. pestis EV induced monokines on Nph functional activity is more pronounced during the secondary immune response, than in the course of the primary one.

Animals↗
PubMedDate not supplied

[Lectin of Yersinia pestis vaccine strain EV and its immunological properties].

As the result of the chromatographic separation of Y. pestis EV membrane proteins, a protein fraction with hemagglutinating activity was obtained. The isolated preparation was glycoprotein with a molecular weight of 22 kD, contained 16% of carbohydrates and exhibited thermolabile properties. The determination of the carbohydrate specificity of this glycoprotein revealed that it belonged to the class of lectins. Changes in the content of 11 corticosteroids and the population composition of lymphocytes, as well as the detection of specific antibodies in the blood serum of guinea pigs immunized with lectin, were indicative of the fact that the preparation was sufficiently immunogenic and induced the activation of the processes of proliferation and activation of lymphocytes during immunogenesis. The lectin isolated from Y. pestis EV outer membrane may be regarded as an additional factor ensuring the contact of the pathogen with the cells of the body and as a promising component of combined plague vaccine.

11-beta-Hydroxysteroid Dehydrogenases↗
PubMedDate not supplied

[Electrophoretic mobility and energy charge of the adenyl system of blood lymphocytes in guinea pigs immunized against plague with strain Yersinia pestis ev subcultures with different immunogenicity].

The injection of highly immunogenic vaccine strain Yersinia pestis EV, line NIIEG, into guinea pigs was accompanied, as early as 24 hours after this injection, by a drop in the electrophoretic mobility of the main amount of lymphocytes, significant shifts in the content and quantitative relation of adenine nucleotides in the mixed lymphocyte population, as well as T and B lymphocytes after their preparative electrophoretic sorting. The immunizatiom of guinea pigs with strain EV of the Japanese line, possessing faint immunogenic properties, produced few changes in the electrophoretic mobility of lymphocytes; no significant changes in the energy charge of the adenylate system of lymphocytes and their subpopulations in comparison with intact animals were established. The study of the metabolic processes in lymphocytes and their populations makes it possible to give more precise characterization to evaluate the prospects of various vaccine preparations.

Adenine Nucleotides↗
PubMed1990

[A polarographic method in assessing the cultural properties of the EV vaccinal strain].

The kinetic and regulatory characteristics of the oxidation metabolism of glucose, whose differences in collection cultures correspond to their capacity for growth in fluid culture medium under the conditions of aeration and the periodic addition of glucose, have been proposed on the basis of the polarographic method used for the registration of microbial breath in vaccine strain EV. Pronounced metabolic disturbances resulting from the prolonged storage of the stock culture and working standards of strain EV lead to the deterioration of their working properties.

Bacterial Vaccines↗
PubMed1988

[Grigor'ev-Shiga dysentery: a new epidemic threat. Its global tendencies and features of its spread].

In this article, based on the data contained in literature, the development of the pandemic of Grigor'ev-Shiga dysentery, which began in 1960-ies, is followed. The stages of the formation of three powerful hyperpandemic foci in Central America, South-East Asia and Central Africa are characterized. The characterization of the epidemiological features of the spread of this disease and its clinical distinction are presented. The biological properties of the causative agent, and in particular its multiple medicinal resistance facilitating the spread of the disease throughout the world, is considered. The stable character of the foci of infection in developing countries, which actually present a threat also for this country, is pointed out. For this reason, the epidemiological surveillance on Grigor'ev-Shiga dysentery should be drastically strengthened.

Africa, Central↗
PubMed1979

[Stability of the immunogenic properties of plague vaccine strain EV, Research Institute of Epidemiology and Hygiene line, during long-term storage].

The experiments in guinea pigs showed that the immunogenic properties of plague vaccine strain EV, line NIIEG, freeze-dried in 1947 and stored under vacuum without animalization, remained unchanged for 30 years. The subcultures prepared from this train showed, after three passages in guinea pigs, good immunogenic properties which preserved for 6--10 years (the term of observation). After 30-years storage the stock culture of strain EV, line NIIEG, can be used for the preparation of NIIS live plague vaccine.

Animals↗
PubMed1984

[Comparison of specific recognition sites of adenine and cytosine DNA-methylase of Yersinia Pestis EV 76 C dam and dcm by Escherichia coli methylases].

Using enzymatic modelling of in vitro methylation of chromosome DNAs from Yersinia pestis EV 76, E. coli 834 and E. coli C600 RII by DNA methylases of Eco RII and Eco dam as well as of DNA hydrolysis of plasmid pBR 322 from the cells of Y. pestis EV 76, E. coli C600 and E. coli 834 by restrictases of Eco RII and Cfu I, it was found that cytosine DNA methylase from plague bacteria does not correspond to the type of RII methylases of E. coli. Adenyl DNA methylase is related to E. coli methylases type dam and modifies adenine in the nucleotide sequence of GATC.

Base Sequence↗
PubMed1995

[Multifactor analysis of the effect of pefloxacin on the dynamics of antibody synthesis to EV vaccine fraction 1 and hemagglutinins].

Multifactor analysis of the effect of pefloxacin on the primary immune response to T-independent bacterial antigen (EV vaccine fraction 1) and to T-dependent cellular antigen (sheep erythrocytes) in mice was carried out with the use of a wide variety of the doses and administration times. It was shown that in the doses corresponding to the average therapeutic ones pefloxacin had no affect on the humoral immune response to the EV vaccine fraction 1 antigens while with the use of the subtherapeutic doses the effect was stimulating. When the doses were higher than the therapeutic ones pefloxacin retarded the antibody formation. The pattern of the dose-time dependence of the pefloxacin effect in regard to the immune response to the T-independent and T-dependent antigens was found to be of various types which could be characteristic of the different action of the drug on the populations of the regulatory lymphocytes and antibody-forming cells.

Animals↗
PubMedDate not supplied

[The epidemiological characteristics of the spread of Grigor'ev-Shiga dysentery in the territories of the former USSR in recent years].

On the basis of special data on the registered cases of Grigor'ev-Shiga dysentery on the territory of the former USSR the spread of this nosological form of Shigella infections since 1980 until the present moment has been analyzed. As shown by this analysis, Grigor'ev-Shiga dysentery is not widely spread on the whole territory of the former USSR, the cases of this disease being mostly registered in Namangan (the Uzbek Republic). The study has shown that the area of the circulation of Shigella dysenteriae 1 is not completely determined. This disease is quite widely spread in some areas of Central Asia, penetrating from these areas to other regions. Everyday contacts have shown to play the main role in the transmission of S. dysenteriae 1 due to poor municipal sanitation facilities and pronounced deficiency in the level of general and sanitary education. The withdrawal of Soviet troops from Afghanistan has led to the rapid improvement of the epidemiological situation on the territory of the former USSR as the result of a sharp decline in the "import" of Shigella dysenteriae 1.

Adolescent↗
PubMed1992

[Effect of rifampicin on the synthesis of antibodies to fraction I of vaccine EV].

Multifactorial analysis was used to study the influence of rifampicin on the dynamics of synthesis of antibodies belonging to IgM and IgG classes in mice immunized by fraction I of the vaccinal strain EV. Equations and quadric surfaces describing individual dynamics of antibody formation within a wide range of antibiotic doses and time of antibody content determination were developed by the experimental data. It was shown that within the range of the doses corresponding to the therapeutic ones in man rifampicin stimulated antibody formation. It had an inhibitory effect on antibody genesis only when used in the doses many times higher than the therapeutic ones.

Animals↗