141 research outputs found
Luminescence and radiation defects in irradiated ruby
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
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
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Neutrino factory
The properties of the neutrino provide a unique window on physics beyond that described by the standard model. The study of subleading effects in neutrino oscillations, and the race to discover CP-invariance violation in the lepton sector, has begun with the recent discovery that Ξ13>0. The measured value of Ξ13 is large, emphasizing the need for a facility at which the systematic uncertainties can be reduced to the percent level. The neutrino factory, in which intense neutrino beams are produced from the decay of muons, has been shown to outperform all realistic alternatives and to be capable of making measurements of the requisite precision. Its unique discovery potential arises from the fact that only at the neutrino factory is it practical to produce high-energy electron (anti)neutrino beams of the required intensity. This paper presents the conceptual design of the neutrino factory accelerator facility developed by the European Commission Framework Programme 7 EUROÎœ Design Study consortium. EUROÎœ coordinated the European contributions to the International Design Study for the Neutrino Factory (the IDS-NF) collaboration. The EUROÎœ baseline accelerator facility will provide 10^21 muon decays per year from 12.6 GeV stored muon beams serving a single neutrino detector situated at a source-detector distance of between 1â500 km and 2â500 km. A suite of near detectors will allow definitive neutrino-scattering experiments to be performed
Roadmap on dynamics of molecules and clusters in the gas phase
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
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
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 5dâ4f 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 5dâ4f 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 Ă
) studies of 5dâ4f emission and 4fâ5d excitation spectra of Gd3+ and Lu3+, which allowed the detailed analysis of electronâlattice 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
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
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
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 5dâ4f 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 5dâ4f 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 Ă
) studies of 5dâ4f emission and 4fâ5d excitation spectra of Gd3+ and Lu3+, which allowed the detailed analysis of electronâlattice 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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