Bose-Einstein correlations at the Z0Z^{0} peak

Presented here is an overview of studies of the manifestations of the Bose-Einstein correlations in the hadronic decays of Z/sup 0/ boson, performed by the LEP experiments. The scope of the overview is confined to studies of two and three particle correlation functions for charged pions, with emphasis on analyses of transverse mass m/sub T/ and directional dependence of the two particle correlation function parameters. (17 refs)

On the T-Odd Quark Fragmentation Function and on Transversal Handedness

The first probe of the correlation of the T-odd one-particle fragmentation function responsible for the left--right asymmetry of fragmentation of a transversely polarized quark is done by using the 1991-95 DELPHI data for $Z\to 2$-jet decay. Integrated over the fraction of longitudinal and transversal momenta, this correlation is of 1.5% order, which means order of 13% for the analyzing power. A rather large ($\approx 10$) handedness transversal to the production plane was observed in the diffractive production of ($\pi^-\pi^+\pi^-$) triples from nuclei by the $40 GeV/c \pi^-$--beam. It was shown that the phenomenon has a clear dynamic origin and resembles the single spin asymmetry behavior. All this makes us hope to use this effects in polarized DIS experiments for transversity measurement.Comment: 10 pp, 5 epsfig, Latex 2e, szjp.cls, epsfig.sty, wrapfig.sty included. Talk in "Spin and Symmetry - Praha98". To be published in Czechoslovak Journal of Physics, Supp

Роль цитокинов в патогенезе инфекционных осложнений при хирургическом лечении механической желтухи желчнокаменного генеза

Aim. To study the content of cytokines in the blood serum of patients with obstructive jaundice of gallstone origin before and after surgical treatment, depending on the development of postoperative complications.Materials and methods. The treatment group consisted of 70 patients with the diagnosis of obstructive jaundice of gallstone origin, verified following a comprehensive clinical and instrumental examination. In 54 patients, the postoperative period was uncomplicated, and in 16 patients, various infectious complications in the postoperative period were revealed. The control group consisted of 125 healthy volunteers. The concentration of six cytokines (interleukin (IL)-2, IL-4, IL-18, IL-10, tumor necrosis factor alpha (TNFα), and interferon gamma (INF γ)) was determined using reagent kits manufactured by Vector-Best LLC (Novosibirsk, Russian Federation) by enzyme-linked immunosorbent assay on the Thermo Scientific analyzer (BioMerieux, France).Results. We identified significantly high concentrations of proinflammatory cytokines in the blood serum of patients with obstructive jaundice of gallstone origin upon admission, compared with the data obtained in the study of blood serum in the control group and in patients with obstructive jaundice after surgery. In the postoperative period in patients with obstructive jaundice without complications, the proinflammatory cytokines are significantly reduced and IL-4 is increased, whereas with the development of infectious complications, the level of proinflammatory cytokines is significantly elevated.Conclusion. In the pathogenesis of obstructive jaundice, a local inflammatory process plays an essential role. This is confirmed by statistically significant changes in the studied cytokines. The established increase in the concentration of IL-4, which has anti-inflammatory activity, indicates its importance in the mechanisms underlying the absence of infectious complications in the postoperative period of obstructive jaundice of gallstone origin. The revealed increase in the levels of IL-18, TNFα, and INFγ in the blood serum of patients suggests their role in the pathogenesis of infectious complications in the postoperative period of obstructive jaundice of gallstone origin. Цель. Изучить содержание цитокинов в сыворотке крови пациентов с механической желтухой желчнокаменного генеза до и после хирургического лечения в зависимости от развития послеоперационных осложнений.Материалы и методы. Основная группа состояла из 70 пациентов с верифицированным на основании комплексного клинико-инструментального обследования диагнозом «механическая желтуха желчнокаменного генеза». У 54 больных послеоперационный период был без осложнений и у 16 больных выявлялись различные инфекционные осложнения в послеоперационном периоде. Контрольную группу составили 125 практически здоровых добровольцев. Концентрацию шести цитокинов (интерлейкина (IL) 2, IL-4, IL-18, IL-10, фактора некроза опухоли α (TNFα), интерферона γ (INFγ)) определяли с использованием набора реагентов производства ЗАО «Вектор-Бест» (г. Новосибирск) методом иммуноферментного анализа на иммуноферментном анализаторе Thermo Scientific (BioMerieux, Франция).Результаты. Установлено наличие статистически значимо высоких концентраций провоспалительных цитокинов в сыворотке крови пациентов с механической желтухой желчнокаменного генеза при поступлении относительно данных, полученных при исследовании сыворотки крови контрольной группы и больных с механической желтухой после операции. В послеоперационном периоде у пациентов с механической желтухой без осложнений статистически значимо снижаются показатели провоспалительных цитокинов и увеличивается IL-4, а при развитии инфекционных осложнений – статистически значимо увеличивается уровень провоспалительных цитокинов.Заключение. В патогенезе механической желтухи важную роль играет локальный воспалительный процесс. Это подтверждается статистически значимыми изменениями изучаемых цитокинов. Установленное нарастание концентрации IL-4, обладающего противовоспалительной активностью, свидетельствует о его значимости в механизмах отсутствия развития инфекционных осложнений в послеоперационном периоде механической желтухи желчнокаменного генеза. Выявленное повышение в сыворотке крови уровня IL-18, TNFα, INFγ позволяет предположить их участие в патогенезе инфекционных осложнений в послеоперационном периоде у пациентов с механической желтухой желчнокаменного генеза

Plant cell wall and the mechanisms of resistance to pathogens

A huge variety of phytopathogens (viruses, bacteria, fungi) are potentially able to infect plant tissues and cause diseases. Numerous plant genes control a complex network of defense mechanisms based on both constitutive and inducible processes. The cell wall is a primary barrier the pathogens have to penetrate to start the infection process. However,it is able to block invasion by most non-specific potential pathogens. The cell wall structure may differ in various plant species. It is based on the net of cellulose microfibrils linked by hemicellulose molecules. Pectin and lignin are the other important cell wall constituents. Dozens of proteins inside the cell wall are involved in structural and metabolic processes as well as in signal transduction and regulatory circuits (more information is available in W allProtDB database). Each of these components contributes to resistance to pathogens. At the points of contact with potential pathogens cell wall structural changes and accumulation of metabolites with antimicrobial, antifungal or antiviral activities occur. Some pathogens could produce hydrolytic enzymes able to degrade cellulose and pectin to counteract these non-specific plant resistance mechanisms. In turn, plants developed the inhibitors of pathogen-related enzymes and this “arms race” is an important part of plant evolution and host-pathogen interaction mechanisms. Plants also can evaluate the cell wall state to compensate for imbalances and deficiencies. For instance, mutants with cellulose deficiency may have a higher lignification rate and a stronger stress response. The cell wall is also a source of signal molecules triggering the initiation of response mechanisms. In total, the plan cell wall is a complex dynamic structure able to prevent infection by most potential (non-specific) pathogens and switch on the mechanisms of plant immune response. The reconstruction of gene networks controlling the cell wall structural and functional organization during the growth, and under normal and stressful conditions is vitally important for understanding the basic molecular mechanisms of development and stress resistance. The mechanisms of specific and non- specific plant resistance to various phytopathogens connected to the cell wall structure are reviewed. The roles of the cell wall constituents in pathogen detection and the induction of defense mechanism are discusse

GENE NETWORK RECONSTRUCTION AND MATHEMATICAL MODELING OF SALVAGE PATHWAYS: REGULATION OF ADENINE PHOSPHORIBOSYLTRANSFERASE ACTIVITY BY STRUCTURALLY SIMILAR SUBSTRATES

SUMMARY Motivation: Development of an in silico cell, a computer resource for modeling and analysis of physiological processes is an urgent task of systems biology and computational biology. Mathematical modeling of the genetic regulation of cell metabolism pathways, in particular, salvage pathways, is an important problem to be solved as part of this line of work. Results: By using the GeneNet technology, we reproduced the gene network of the regulation of salvage pathways in the E. coli cell. Mathematical models were constructed by the method of generalized Hill functions to describe the efficiency of enzyme systems and regulation of expression of genes coding for these enzymes. Availability: The diagram of the gene network is available through the GeneNet viewer at http://wwwmgs.bionet.nsc.ru/mgs/gnw/genenet/viewer/index.shtml. Models are available on request

A database on genes increasing resistance of wheat and relative species against pathogenic fungi

Fungi belong to the major plant pathogens and investigation of plant resistance genes is a quite important task. During the last years many wheat resistance genes were identified. However, the sequencing of the Triticum aestivum L. genome is still going on and the nucleotide sequences of most resistance genes are not yet known. In addition, the study of allelic variants of resistance genes is important for better understanding of the molecular mechanisms of their action. In this paper we present an information resource for accumulation of data on sequenced genes of wheat and its relatives providing resistance against diseases caused by fungal pathogens. The database (Pathogenesis-Related Genes, PRG) contains information on gene chromosomal localizations and functional activities, nucleotide sequences and single nucleotide polymorphisms associated with their effects. PRG provides data on the proteins encoded, pathogens and diseases, as well as on the resistance gene expression patterns in response to pathogen inoculations, exposure to hormones and various external stimuli. It also has cross-references with related entries from the databases on nucleotide sequences (GenBank) and proteins (UniProt). Information entered into the database is a result of the annotation of scientific publications and manual curation. Currently PRG compiles data on 75 allelic variants of 66 resistance genes. The PRG database was developed on the basis of the SRS (Sequence Retrieval System) platform. This system allows the use of complex queries and visualization tools and automatically generates www-interface with the information in table or text formats. PRG may be useful for researchers studying plant biology or breeding new plant cultivars resistant to fungal diseases. It is available at the address: http://srs6.bionet.nsc.ru/srs6bin/cgi-bin/wgetz?-page+top+-newId

The relationship between the genetic status of the Vrn-1 locus and the size of the root system in bread wheat (Triticum aestivum L.)

One of the main ways to fine-tune the adaptive potential of wheat cultivars is to regulate the timing of flowering using the genes of the Vrn-1 locus, which determines the type and rate of development. Recently, with the use of introgression and isogenic lines of bread wheat, it was shown that this locus is involved in the genetic control of root length and weight both under irrigation and drought conditions. It turned out that the VrnA1 gene is associated with a significant decrease in the size of the root system in a winter genotype. The Vrn-A1 gene had the strongest effect on the reduction of the root system in comparison with the homoeoallelic genes Vrn-B1 and Vrn-D1. The aim of this work was to determine whether the allelic composition of the genes at the Vrn-1 locus affects the root size in seven spring cultivars and in two lines of bread wheat differing in flowering time under conditions of normal watering and drought. The research was carried out in a hydroponic greenhouse; drought was created at the tillering stage. In this work, we have shown that early flowering wheat cultivars with the dominant Vrn-A1а allele have more lightweight and shorter roots under normal watering conditions compared to the late flowering carriers of the dominant homoeoalleles Vrn-B1 and Vrn-D1. In drought conditions, the root length decreased insignificantly, but the weight of the roots significantly decreased in all genotypes, with the exception of Diamant 2. It has been hypothesized that the level of the transcription factor VRN-1 at the onset of drought may affect the size of the root system. The large variability in root weight may indicate the participation, in addition to the Vrn-1 locus, of other gene networks in the formation of this trait. Breeders working to develop early maturing varieties should consider the possibility of reducing the root size, especially in arid conditions. A significant increase in the root size of line 821 with introgressions into chromosomes 2A, 2B, and 5A from T. timopheevii indicates the possibility of using congeners as a source of increasing the trait in wheat

CEP-stable Tunable THz-Emission Originating from Laser-Waveform-Controlled Sub-Cycle Plasma-Electron Bursts

We study THz-emission from a plasma driven by an incommensurate-frequency two-colour laser field. A semi-classical transient electron current model is derived from a fully quantum-mechanical description of the emission process in terms of sub-cycle field-ionization followed by continuum-continuum electron transitions. For the experiment, a CEP-locked laser and a near-degenerate optical parametric amplifier are used to produce two-colour pulses that consist of the fundamental and its near-half frequency. By choosing two incommensurate frequencies, the frequency of the CEP-stable THz-emission can be continuously tuned into the mid-IR range. This measured frequency dependence of the THz-emission is found to be consistent with the semi-classical transient electron current model, similar to the Brunel mechanism of harmonic generation

The High A(V) Quasar Survey: Reddened quasi-stellar objects selected from optical/near-infrared photometry - II

Quasi-stellar objects (QSOs) whose spectral energy distributions (SEDs) are reddened by dust either in their host galaxies or in intervening absorber galaxies are to a large degree missed by optical color selection criteria like the one used by the Sloan Digital Sky Survey (SDSS). To overcome this bias against red QSOs, we employ a combined optical and near-infrared color selection. In this paper, we present a spectroscopic follow-up campaign of a sample of red candidate QSOs which were selected from the SDSS and the UKIRT Infrared Deep Sky Survey (UKIDSS). The spectroscopic data and SDSS/UKIDSS photometry are supplemented by mid-infrared photometry from the Wide-field Infrared Survey Explorer. In our sample of 159 candidates, 154 (97%) are confirmed to be QSOs. We use a statistical algorithm to identify sightlines with plausible intervening absorption systems and identify nine such cases assuming dust in the absorber similar to Large Magellanic Cloud sightlines. We find absorption systems toward 30 QSOs, 2 of which are consistent with the best-fit absorber redshift from the statistical modeling. Furthermore, we observe a broad range in SED properties of the QSOs as probed by the rest-frame 2 {\mu}m flux. We find QSOs with a strong excess as well as QSOs with a large deficit at rest-frame 2 {\mu}m relative to a QSO template. Potential solutions to these discrepancies are discussed. Overall, our study demonstrates the high efficiency of the optical/near-infrared selection of red QSOs.Comment: 64 pages, 18 figures, 16 pages of tables. Accepted to ApJ