141 research outputs found

    Luminescence and radiation defects in irradiated ruby

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    The excitations of luminescence in irradiated and non-irradiated ruby crystals are investigated by means of highly polarized synchrotron radiation. In the VUV luminescence spectra the existence of quick and slow emission was observed in irradiated and nonirradiated crystals. The luminescence bands with maximum at 3.8 eV are produced by F+ centers. A new type of quick luminescence was established for the band at 4.6 eV. It is called cross-luminescence and is connected with the recombination of valence band electrons with holes in low-lying core levels. It is shown that the band at 3.0 eV is not due to anionic centers (F-centers), but is determined by a short lifetime emission center

    Ultrasound examination with contrast in the diagnosis of inflammatory bowel disease. The results of the pilot study

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    Aim. Assessment of diagnostic significance of informativeness and security of ultrasonography with contrast enhancement drug SonoVue in the diagnosis of Crohn's disease (CD) and ulcerative colitis (UC). Materials and methods. The pilot conducted a prospective study which involved 15 patients with inflammatory bowel disease (IBD). All patients gave written consent to participate in the study and processing of personal data. The study included adult patients with an established diagnosis of UC and CD, with proven clinical activity of the disease. Activity was evaluated based on clinical and laboratory data on the scale of best (CDAI >150) for patients with CD and on a scale of Trulove-Witts (2-3 stage) and the Mayo index (DAI) for patients with UC. All the patients underwent colonoscopy with biopsy, ultrasound examination of abdominal cavity organs with the study of the vascularization of the intestinal wall (color Doppler, power Doppler, contrast study). Results. The use of contrast showed additional features in the instrumental evaluation of activity of inflammatory process, identification of complications and assessment of prognosis. Conclusion. The results of ultrasound of the bowel with contrast can be used to assess the activity and stage of disease in patients with UC or CD

    Roadmap on dynamics of molecules and clusters in the gas phase

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    This roadmap article highlights recent advances, challenges and future prospects in studies of the dynamics of molecules and clusters in the gas phase. It comprises nineteen contributions by scientists with leading expertise in complementary experimental and theoretical techniques to probe the dynamics on timescales spanning twenty order of magnitudes, from attoseconds to minutes and beyond, and for systems ranging in complexity from the smallest (diatomic) molecules to clusters and nanoparticles. Combining some of these techniques opens up new avenues to unravel hitherto unexplored reaction pathways and mechanisms, and to establish their significance in, e.g. radiotherapy and radiation damage on the nanoscale, astrophysics, astrochemistry and atmospheric science

    Listeria pathogenesis and molecular virulence determinants

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    The gram-positive bacterium Listeria monocytogenes is the causative agent of listeriosis, a highly fatal opportunistic foodborne infection. Pregnant women, neonates, the elderly, and debilitated or immunocompromised patients in general are predominantly affected, although the disease can also develop in normal individuals. Clinical manifestations of invasive listeriosis are usually severe and include abortion, sepsis, and meningoencephalitis. Listeriosis can also manifest as a febrile gastroenteritis syndrome. In addition to humans, L. monocytogenes affects many vertebrate species, including birds. Listeria ivanovii, a second pathogenic species of the genus, is specific for ruminants. Our current view of the pathophysiology of listeriosis derives largely from studies with the mouse infection model. Pathogenic listeriae enter the host primarily through the intestine. The liver is thought to be their first target organ after intestinal translocation. In the liver, listeriae actively multiply until the infection is controlled by a cell-mediated immune response. This initial, subclinical step of listeriosis is thought to be common due to the frequent presence of pathogenic L. monocytogenes in food. In normal indivuals, the continual exposure to listerial antigens probably contributes to the maintenance of anti-Listeria memory T cells. However, in debilitated and immunocompromised patients, the unrestricted proliferation of listeriae in the liver may result in prolonged low-level bacteremia, leading to invasion of the preferred secondary target organs (the brain and the gravid uterus) and to overt clinical disease. L. monocytogenes and L. ivanovii are facultative intracellular parasites able to survive in macrophages and to invade a variety of normally nonphagocytic cells, such as epithelial cells, hepatocytes, and endothelial cells. In all these cell types, pathogenic listeriae go through an intracellular life cycle involving early escape from the phagocytic vacuole, rapid intracytoplasmic multiplication, bacterially induced actin-based motility, and direct spread to neighboring cells, in which they reinitiate the cycle. In this way, listeriae disseminate in host tissues sheltered from the humoral arm of the immune system. Over the last 15 years, a number of virulence factors involved in key steps of this intracellular life cycle have been identified. This review describes in detail the molecular determinants of Listeria virulence and their mechanism of action and summarizes the current knowledge on the pathophysiology of listeriosis and the cell biology and host cell responses to Listeria infection. This article provides an updated perspective of the development of our understanding of Listeria pathogenesis from the first molecular genetic analyses of virulence mechanisms reported in 1985 until the start of the genomic era of Listeria research

    Vacuum ultraviolet luminescence of wide band-gap solids studied using time-resolved spectroscopy with synchrotron radiation

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    Some highlights of the time-resolved vacuum ultraviolet (VUV) luminescence spectroscopy of solids using synchrotron radiation (SR) are outlined, including studies of the unique phenomenon crossluminescence (CL) and the contribution of time-resolved VUV spectroscopy to the understanding of 5d–4f transitions of rare earth ions in solids. The main properties of CL studied at different SR sources are described and some unclear aspects of CL are pointed out. The results of recent studies of some CL-active nanosize materials are presented. We describe the time-resolved experiments which led to the discovery of 5d–4f luminescence in the deep VUV region (near 10 eV) of Gd3+ and Lu3+ ions incorporated into some wide band-gap fluoride hosts. The results of high-resolution (~ 0.5 Å) studies of 5d–4f emission and 4f–5d excitation spectra of Gd3+ and Lu3+, which allowed the detailed analysis of electron–lattice coupling in these systems, are presented. Possible newdevelopments in the femtosecond time-resolved spectroscopy of solids with a free electron laser are discussed

    Development of functions of specialist in criminal procedure of the Russian Federation

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    In the article the content of the expert in the criminal proceedings of the Russian Federation, it differs from a court expert, his rights and duties, an analysis of the new activities of the expert: study of the case with the use of technical means, the conclusion and the testimony of the expert

    Preliminary investigation in criminal procedure of Russian Federation

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    The article deals with the analysis of two exclusive institutes in preliminary investigation in criminal procedure of the Russian Federation, a stage of initiation of legal proceedings and the investigator

    Vacuum Ultraviolet Luminescence of Wide Band-Gap Solids Studied Using Time-Resolved Spectroscopy with Synchrotron Radiation

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    Some highlights of the time-resolved vacuum ultraviolet (VUV) luminescence spectroscopy of solids using synchrotron radiation (SR) are outlined, including studies of the unique phenomenon crossluminescence (CL) and the contribution of time-resolved VUV spectroscopy to the understanding of 5d–4f transitions of rare earth ions in solids. The main properties of CL studied at different SR sources are described and some unclear aspects of CL are pointed out. The results of recent studies of some CL-active nanosize materials are presented. We describe the time-resolved experiments which led to the discovery of 5d–4f luminescence in the deep VUV region (near 10 eV) of Gd3+ and Lu3+ ions incorporated into some wide band-gap fluoride hosts. The results of high-resolution (~ 0.5 Å) studies of 5d–4f emission and 4f–5d excitation spectra of Gd3+ and Lu3+, which allowed the detailed analysis of electron–lattice coupling in these systems, are presented. Possible newdevelopments in the femtosecond time-resolved spectroscopy of solids with a free electron laser are discussed
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