Studies of contribution of metals bonded with organic matter of seawater to the fluxes of total dissolved metals across water-sediment interface at Vistula Lagoon of Baltic Sea

© 2004 IEEE. Investigations of fluxes of a dissolved element across the water-sediment interface in Vistula Lagoon (Baltic Sea) were carried out in August 2001 and 2002, using chamber experiments. Oxygen, iron(II), total dissolved iron, manganese, copper and lead fluxes were calculated. For the first time the fluxes of metals bonded with organic matter of sea water were studied. The contribution of metals bonded with organic matter to the total flux was varied depending upon conditions and may reach up to 70 %. It was found that metal fluxes at the coastal zone are larger than at the center of the lagoon by the factor of 2-4

Studies of fluxes of dissolved iron and manganese in the Gulf of Finland

© 2004 IEEE. Metal fluxes (total dissolved iron and manganese) across the water-sediment interface were studied in situ in the Gulf of Finland in June 2002 and 2003 using an autonomous benthic lander. Distribution of these metals in the sediment and the porewater was also investigated. Focus was given to understand the behavior of the studied metals at various redox conditions and the influence when sediment resuspension is occurring. Our data indicate the importance of the redox conditions for the iron fluxes with no fluxes at oxic, intermediate at anoxic and high fluxes at suboxic conditions. The fluxes of manganese do not seem to have any correlation with the oxygen levels. Both metals were significantly affected by resuspension, which led to a rapid release

Эффективность химиотерапии и стойкость клинического излечения у впервые выявленных больных деструктивным туберкулезом легких с позиций доказательной медицины

Summary. A randomized multicenter clinical study of chemotherapy efficacy, clinical cure and early recurrence rate involved 240 newly diagnosed patients with cavitary pulmonary tuberculosis treated in municipal and penitentiary medical facilities. Given the primary multiple drug resistance (MDR) of 22.5–33.3 %, intensive chemotherapy with isoniazid, rifampicin, pyrazinamide, ethambutol, kanamycin (or amikacin) and ofloxacin (or lev ofloxacin) allowed to achieve sputum conversion in 100 % of smearpositive patients using sputum microscopy and in 89.2 % using sputum culture, cavity closure in 71.7 %, and clinical cure in 94.2 % with early recurrence rate of 2.6 % in comparison to 54.2, 45.8, 45.8, 65 and 20.5 % respectively in patients treated with isoniazid, rifampicin, pyrazinamide and ethambutol. Lung fibrocavitary lesions with high level of MDR developed in 55 % of patients and were associated with high cost of treatment due to the need in expensive salvage chemotherapy regimens and hightech surgical inter ventions.Резюме. Было проведено рандомизированное многоцентровое клиническое исследование эффективности химиотерапии, клинического излечения и частоты ранних рецидивов у 240 впервые выявленных больных деструктивным туберкулезом легких в гражданских и пенитенциарных противотуберкулезных учреждениях. Доказано, что при уровне первичной множественной лекарственной устойчивости (МЛУ) 22,5–33,3 % режим химиотерапии изониазидом, рифампицином, пиразинамидом, этамбутолом, канамицином (амикацин) и офлоксацином (левофлоксацин) в интенсивной фазе лечения позволяет добиться прекращения бактериовыделения по результатам микроскопии мокроты у 100 % больных и по посеву – у 89,2 %, закрытия каверн – у 71,7 %, клинического излечения – у 94,2 % и ранних рецидивов – у 2,6 % пациентов. В то время как режим химиотерапии изониазидом, рифампицином, пиразинамидом, этамбутолом – у 54,2; 45,8; 45,8; 65 и 20,5 % больных соответственно. При этом в 55 % случаев констатировано формирование фибрознокавернозного туберкулеза с высоким уровнем вторичной МЛУ, что требует больших экономических затрат на дорогостоящие резервные препараты и высокотехнологичные оперативные вмешательства

The Polarization of Radiation in Single Cristals in the Quasiclassical Approach

The radiation emission spectra of polarized photons emitted from charged particles in single oriented crystals are obtained in Bayer-Katkov quasiclassical approach. The results of numerical calculations are presented in the region of small angles of incidence for which the coherent theory fails but magnetic bremsstrahlung region isn't yet achieved. The spectral distribution of linear polarization degree repeats, in general, the form of the intensity distribution. At sufficiently small angles, in the case of planar orientation of crystal, there is a wide maximum of essential linear polarization at low frequencies.Comment: Latex with 3 figures (.eps files). used epsfig.sty and wrapfig.st

Ce-doped Li6Ln(BO3)3 (Ln = Y, Gd) Single crystals fibers grown by micro-pulling down method and luminescence properties

Ce3+-doped borate crystal fibers of Li6Gd(BO 3)3 (LGBO) and Li6Y(BO3)3 (LYBO) compositions are grown by the micro-pulling down (μ-PD) method for potential application in developing new neutron detectors. The ternary equilibrium diagram of Li2O-Gd2O3-B 2O3 is drawn and the preparations of homogeneous mixed LGBO and LYBO powders and growth conditions for single crystal fibers are discussed. Absorption, excitation and X-ray luminescence spectra are investigated. Absolute light yield derived from energy spectra and kinetic decay curves measured under α- and γ-scintillations of Ce 3+-doped LGBO and LYBO single crystal fibers is provided. © 2012 Elsevier B.V. All rights reserved

Linear to Circular Polarisation Conversion using Birefringent Properties of Aligned Crystals for Multi-GeV Photons

We present the first experimental results on the use of a thick aligned Si crystal acting as a quarter wave plate to induce a degree of circular polarisation in a high energy linearly polarised photon beam. The linearly polarised photon beam is produced from coherent bremsstrahlung radiation by 178 GeV unpolarised electrons incident on an aligned Si crystal, acting as a radiator. The linear polarisation of the photon beam is characterised by measuring the asymmetry in electron-positron pair production in a Ge crystal, for different crystal orientations. The Ge crystal therefore acts as an analyser. The birefringence phenomenon, which converts the linear polarisation to circular polarisation, is observed by letting the linearly polarised photons beam pass through a thick Si quarter wave plate crystal, and then measuring the asymmetry in electron-positron pair production again for a selection of relative angles between the crystallographic planes of the radiator, analyser and quarter wave plate. The systematics of the difference between the measured asymmetries with and without the quarter wave plate are predicted by theory to reveal an evolution in the Stokes parameters from which the appearance of a circularly polarised component in the photon beam can be demonstrated. The measured magnitude of the circularly polarised component was consistent with the theoretical predictions, and therefore is in indication of the existence of the birefringence effect.Comment: 12 pages, 12 figures, 1 table, REVTeX4 two column, Version for publicatio

Coherent Pair Production by Photons in the 20-170 GeV Energy Range Incident on Crystals and Birefringence

The cross section for coherent pair production by linearly polarised photons in the 20-170 GeV energy range was measured for photon aligned incidence on ultra-high quality diamond and germanium crystals. The theoretical description of coherent bremsstrahlung and coherent pair production phenomena is an area of active theoretical debate and development. However, under our experimental conditions, the theory predicted the combined cross section and polarisation experimental observables very well indeed. In macroscopic terms, our experiment measured a birefringence effect in pair production in a crystal. This study of this effect also constituted a measurement of the energy dependent linear polarisation of photons produced by coherent bremsstrahlung in aligned crystals. New technologies for manipulating high energy photon beams can be realised based on an improved understanding of QED phenomena at these energies. In particular, this experiment demonstrates an efficient new polarimetry technique. The pair production measurements were done using two independent methods simultaneously. The more complex method using a magnet spectrometer showed that the simpler method using a multiplicity detector was also viable.Comment: 10 pages, 13 figures, 1 table, REVTeX4 two column, Version for publicatio

Results on the Coherent Interaction of High Energy Electrons and Photons in Oriented Single Crystals

The CERN-NA-59 experiment examined a wide range of electromagnetic processes for multi-GeV electrons and photons interacting with oriented single crystals. The various types of crystals and their orientations were used for producing photon beams and for converting and measuring their polarisation. The radiation emitted by 178 GeV unpolarised electrons incident on a 1.5 cm thick Si crystal oriented in the Coherent Bremsstrahlung (CB) and the String-of-Strings (SOS) modes was used to obtain multi-GeV linearly polarised photon beams. A new crystal polarimetry technique was established for measuring the linear polarisation of the photon beam. The polarimeter is based on the dependence of the Coherent Pair Production (CPP) cross section in oriented single crystals on the direction of the photon polarisation with respect to the crystal plane. Both a 1 mm thick single crystal of Germanium and a 4 mm thick multi-tile set of synthetic Diamond crystals were used as analyzers of the linear polarisation. A birefringence phenomenon, the conversion of the linear polarisation of the photon beam into circular polarisation, was observed. This was achieved by letting the linearly polarised photon beam pass through a 10 cm thick Silicon single crystal that acted as a "quarter wave plate" (QWP) as suggested by N. Cabibbo et al.Comment: Presented at International workshop "Relativistic Channeling and Related Coherent Phenomena", Frascati (Rome) 23-26 March 200

Coherent bremsstrahlung, boherent pair production, birefringence and polarimetry in the 20-170 GeV energy range using aligned crystals

The processes of coherent bremsstrahlung (CB) and coherent pair production (CPP) based on aligned crystal targets have been studied in the energy range 20-170 GeV. The experimental arrangement allowed for measurements of single photon properties of these phenomena including their polarization dependences. This is significant as the theoretical description of CB and CPP is an area of active theoretical debate and development. With the theoretical approach used in this paper both the measured cross sections and polarization observables are predicted very well. This indicates a proper understanding of CB and CPP up to energies of 170 GeV. Birefringence in CPP on aligned crystals is applied to determine the polarization parameters in our measurements. New technologies for high energy photon beam optics including phase plates and polarimeters for linear and circular polarization are demonstrated in this experiment. Coherent bremsstrahlung for the strings-on-strings (SOS) orientation yields a larger enhancement for hard photons than CB for the channeling orientations of the crystal. Our measurements and our calculations indicate low photon polarizations for the high energy SOS photons.Comment: 23 pages, 27 figures, 2 tables, REVTeX4 two column