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Sample records for gd tb er

  1. Preparation and characterization of ZnS:Tb,Gd and ZnS:Er,Yb,Gd nanoparticles for bimodal magnetic-fluorescent imaging.

    Science.gov (United States)

    Wei, Xiaojun; Wang, Wei; Chen, Kezheng

    2013-02-07

    As bimodal magnetic-fluorescent imaging agents, the preparation of ZnS:Tb,Gd and ZnS:Er,Yb,Gd nanoparticles via a facile homogeneous precipitation method is reported. The results show that these nanoparticles are almost spherical in shape with a diameter of 100-200 nm approximately and a major phase of wurtzite-structured ZnS. The products can successfully label the human hepatocellular carcinoma (HepG2) cells and present low toxicity even at concentrations up to 5 mg mL(-1). Additionally, for the ZnS:Er,Yb,Gd nanoparticles calcinated above 950 °C, NIR-to-visible up-conversion fluorescence were obtained, which is believed to be superior to traditional ZnS-based bioimaging agents with down conversion. In MRI studies, they reveal a longitudinal relaxivity rate (r(1)) of 39.46 mM(-1) s(-1) and 57.8 mM(-1) s(-1), respectively, which are much larger than the conventional Gd-DTPA and currently reported Gd-base nanoparticles, suggesting great potential as MRI agents.

  2. Strong paramagnetic crystalline LnVO{sub 4} (Ln: Gd, Tb, Dy, Ho, Er) nanoparticles synthesized by a fabricating method

    Energy Technology Data Exchange (ETDEWEB)

    Bulbul, Berna; Beyaz, Seda, E-mail: sedacan@balikesir.edu.tr

    2016-04-15

    Strong paramagnetic lanthanide orthovanadate (LnVO{sub 4}, Ln: Gd, Tb, Dy, Ho, Er) nanoparticles were synthesized under ambient conditions by a novel precipitation method that is economical and fabricating. To the X-ray diffraction patterns, all samples are well-crystallized zircon type orthovanadate and have pure tetragonal phase. Their crystal sizes increased from 12.58 to 15.12 nm with increasing the ionic radii of lanthanide. As confirmed with the surface observation by a transmission electron microscope, it was identified that their two-dimensional projection is an ellipse with the two major axes. It was seen that the sizes of nanoparticles (14.40nm-70.69 nm) were bigger than the crystal sizes because of their polycrystalline structures. Besides, the particle sizes increased with reduction of ionic radii of lanthanide. The magnetic properties obtained from a vibrating sample magnetometer revealed that all nanoparticles are strong paramagnetic at room temperature showing an increase in molar susceptibility up to 4.79 × 10{sup −1} cm{sup 3} mol{sup −1}. Such highly crystalline, small and paramagnetic nanoparticles could be thought to be convenient for biomedical applications. - Highlights: • A general fabricating method for lanthanide orthovanadate nanoparticles is proposed. • The method generates highly small and crystalline nanoparticles. • The reduction in ionic radius of lanthanide (Ln{sup 3+}) causes to increase particle size.

  3. Síntesis hidrotermal de monocristales LnMn2O5 (Ln= Y, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho y Er

    Directory of Open Access Journals (Sweden)

    Señarís Rodríguez, M. A.

    2008-08-01

    Full Text Available Ten single crystals of the series LnMn2O5 (Ln= Y, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho and Er were synthesized by hydrothermal synthesis in a single step and without subsequent thermal treatments from aqueous solutions of metals salts at 240 ºC. The obtained single crystals have a size of various micrometers and their morphology changes throughout the serie: they are polygonal in the case of the compounds with Ln= Pr, Nd, Sm, Eu and Gd and needle-like in the case of the compounds with Ln= Y, Tb, Dy, Ho and Er. After the analysis of the obtained products employing different conditions of synthesis we attributed the different morphology to a greater growth rate along the c axis when the smaller ions (Y, Tb, Dy, Ho y Er are involved, due to their better adaptation to the compound’s crystal structure.Se han conseguido preparar monocristales de 10 óxidos mixtos de la serie LnMn2O5 (Ln= Y, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho y Er mediante síntesis hidrotermal optimizada, en un único paso y sin tratamientos térmicos posteriores partiendo de las correspondientes sales metálicas en disolución acuosa a 240 ºC. Los monocristales obtenidos son relativamente grandes, de varias micras y su morfología varía a lo largo de la serie: es poligonal en el caso de los compuestos de los lantánidos del inicio de la serie (Ln= Pr, Nd, Sm, Eu y Gd y acicular en el caso de los compuestos de Y y de los lantánidos del final de la serie (Ln= Tb, Dy, Ho y Er. Tras el análisis de los productos obtenidos empleando distintas condiciones de síntesis atribuimos la diferente morfología a una mayor velocidad de crecimiento cristalino a lo largo del eje c cuando intervienen los iones más pequeños (Y, Tb, Dy, Ho y Er debido a la mejor adaptación de éstos últimos a la estructura cristalina del compuesto.

  4. Synthesis and magnetism of μ-oxamido-bridged Cu2IILnIII - type heterotrinuclear complexes (Ln = Ce, Nd, Sm, Eu, Gd, Tb, Dy, Er)

    International Nuclear Information System (INIS)

    Li, Y.T.; Yan, C.W.

    2001-01-01

    Eight new Cu 2 II Ln III - type (Ln = Ce, Nd, Sm, Eu, Gd, Tb, Dy, Er) heterotrinuclear complexes bridged by N,N'-bis (2-aminopropyl)oxamidocopper(II) [Cu(oxdn)], namely Cu 2 (oxdn)Ln(NO 3 ) 3 , have been synthesized and characterized by elemental analyses, molar conductivity measurements and spectroscopic (IR, UV, ESR) studies. Magnetic susceptibility measurements (4.2 ∼300 K) and studies of Cu 2 (oxdn)Gd(NO 3 ) 3 complex have revealed that the central gadolinium(III) and terminal copper(II) ions are ferromagnetically coupled with the exchange integral J (Cu-Gd) = +2.98 cm -1 , while an antiferromagnetic coupling is detected between the terminal copper(II) metal ions with the exchange integral J' (Cu-Gd) = -0.75 cm -1 , on the basis of the spin Hamiltonian operator [H -2J(S Cu1 -S Gd +S Cu2 +S Gd )-2J'(S Cu1 S Cu2 )]. (author)

  5. Critical evaluation and thermodynamic optimisation of the Si-RE systems: Part II. Si-RE system (RE = Gd, Tb, Dy, Ho, Er, Tm, Lu and Y)

    International Nuclear Information System (INIS)

    Kim, Junghwan; Jung, In-Ho

    2015-01-01

    Highlights: • The (Si-RE) (RE = Gd, Tb, Dy, Ho, Er, Tm, Lu and Y) systems have been reviewed. • The thermodynamic optimization of the (Si-RE) systems have been performed. • Systematic changes and similarities in the (Si-RE) systems were found. • The systematic approach resolved inconsistencies in the experimental data. • The systematic approach was used to assess the unexplored phase diagrams. - Abstract: A critical evaluation and optimisation of all available phase diagrams and thermodynamic data of the (Si-RE) (RE = Gd, Tb, Dy, Ho, Er, Tm, Lu and Y) systems was conducted to obtain reliable thermodynamic functions of all the phases in the system. In the thermodynamic modelling, a systematic analysis involving the similarity and periodicity observed in the lanthanide series was applied to resolve inconsistencies in the experimental data and to estimate the unknown thermodynamic properties and phase equilibria data. In particular, the phase diagrams and thermodynamic properties of (Si-Tm) and (Si-Lu) systems which are rarely investigated can be predicted from this approach. Systematic trends in thermodynamic properties of solid and liquid phases and phase diagram of the entire (Si-RE) systems were summarized

  6. Crystal structure of RCoIn5 (R - Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Y) and R2CoIn8 (R - Ce, Pr, Nd, Sm, Gd, Dy, Ho, Er, Tm, Y) compounds

    International Nuclear Information System (INIS)

    Kalychak, Ya.M.; Zaremba, V.I.; Baranyak, V.M.; Bruskov, V.A.; Zavalij, P.Yu.

    1989-01-01

    Usng X-ray diffraction method of monocrystal, crystal structure of HoCoIn 5 compound belonging to the HoCoGa 5 structural type is determined. Using the method of powder belonging of CeCoIn 5 structure to the HoCoGa 5 structural type is confirmed. Isostructural compounds with Y, Pr, Nd, Sm, Gd, Tb, Dy are detected. Their lattice periods are determined. Using the method of powder belonging of Ce 2 CoIn 8 compound structure to Ho 2 CoGa 8 structural type is determined. Isostructural compounds with Y, Pr, Nd, Sm, Gd, Dy, Ho, Er, Tm are detected and their lattice periods are determined

  7. The isothermal section at 500 deg. C of the Gd-Tb-Ga ternary system

    International Nuclear Information System (INIS)

    Li, J.Q.; Jian, Y.X.; Ao, W.Q.; Zhuang, Y.H.; He, W.

    2006-01-01

    Phase equilibria in the Gd-Tb-Ga ternary system at 500 deg. C were investigated by X-ray powder diffraction and differential scanning calorimetry. The binary compounds, Gd 5 Ga 3 , Gd 3 Ga 2 , GdGa, GdGa 2 , Tb 5 Ga 3 , TbGa, TbGa 2 and TbGa 3 have been confirmed at 500 deg. C. No ternary compound was found in this system. The isothermal section of this system at 500 deg. C was constructed. It is composed of 7 single-phase regions, 8 two-phase regions and 2 three-phase regions. Four ternary continuous solid solutions (Gd, Tb), (Gd, Tb) 5 Ga 3 , (Gd, Tb)Ga, (Gd, Tb)Ga 2 were formed in this isothermal section. The maximum solid solubilities of Ga in (Gd, Tb) at 500 deg. C is 5.0 at.%. The homogeneity range of (Gd, Tb)Ga 2 is from 20 to 33.3 at.% Ga in Gd-Ga side but limited in Tb-Ga side. The solid solubilities of Ga in the other phases cannot be detected. The Curie temperatures of the Gd 0.6 Tb 0.4-x Ga x alloys increase from 270 to 298 K as x increases from 0 to 0.03

  8. Enhance the Er3+ Upconversion Luminescence by Constructing NaGdF4:Er3+@NaGdF4:Er3+ Active-Core/Active-Shell Nanocrystals.

    Science.gov (United States)

    Du, Xiaoyu; Wang, Xiangfu; Meng, Lan; Bu, Yanyan; Yan, Xiaohong

    2017-12-01

    NaGdF 4 :12%Er 3+ @NaGdF 4 :x%Er 3+ (x = 0, 6, 8, 10, and 12) active-core/active-shell nanoparticles (NPs) were peculiarly synthesized via a delayed nucleation pathway with procedures. The phase, shape, and size of the resulting core-shell NPs are confirmed by transmission electron microscopy and X-ray diffraction. Coated with a NaGdF 4 :10%Er 3+ active shell around the NaGdF 4 :12%Er 3+ core NPs, a maximum luminescent enhancement of about 336 times higher than the NaGdF 4 :12%Er 3+ core-only NPs was observed under the 1540 nm excitation. The intensity ratio of green to red was adjusted through the construction of the core-shell structure and the change of Er 3+ concentration in the shell. By analyzing the lifetimes of emission bands and exploring the energy transition mechanism, the giant luminescence enhancement is mainly attributed to the significant increase in the near-infrared absorption at 1540 nm and efficient energy migration from the shell to core.

  9. Cross sections of proton-induced reactions on {sup 152}Gd, {sup 155}Gd and {sup 159}Tb with emphasis on the production of selected Tb radionuclides

    Energy Technology Data Exchange (ETDEWEB)

    Steyn, G.F., E-mail: deon@tlabs.ac.za [iThemba Laboratory for Accelerator Based Sciences, P.O. Box 722, Somerset West 7129 (South Africa); Vermeulen, C. [iThemba Laboratory for Accelerator Based Sciences, P.O. Box 722, Somerset West 7129 (South Africa); Szelecsényi, F.; Kovács, Z. [Cyclotron Application Department, ATOMKI, P.O. Box 51, H-4001 Debrecen (Hungary); Hohn, A. [Department of Nuclear Medicine, University Medical Centre Rostock, Rostock (Germany); Meulen, N.P. van der [Laboratory of Radiochemistry and Environmental Chemistry, Paul Scherrer Institute, 5232 Villigen-PSI (Switzerland); Center of Radiopharmaceutical Science, Paul Scherrer Institute, 5232 Villigen-PSI (Switzerland); Schibli, R. [Center of Radiopharmaceutical Science, Paul Scherrer Institute, 5232 Villigen-PSI (Switzerland); Walt, T.N. van der [Faculty of Applied Sciences, Cape Peninsula University of Technology, P.O. Box 1906, Bellville 7535 (South Africa)

    2014-01-15

    Cross sections are presented for various Dy, Tb and Gd radionuclides produced in the proton bombardment of {sup 159}Tb as well as for the reactions {sup 152}Gd(p,4n){sup 149}Tb and {sup 155}Gd(p,4n){sup 152}Tb up to 66 MeV. The experimental excitation functions are compared with theoretical predictions by means of the geometry-dependent hybrid (GDH) model as implemented in the code ALICE/ASH, as well as with values from the TENDL-2012 library and previous literature experimental data, where available. Physical yields have been derived for the production of some of the medically important radioterbiums, namely {sup 149}Tb (radionuclide therapy), {sup 152}Tb (PET) and {sup 155}Tb (SPECT). The indirect production of high-purity {sup 155}Tb via the decay of its precursor {sup 155}Dy is reported. The possibility of a large-scale production facility based on a commercial 70 MeV cyclotron is also discussed.

  10. Synthesis, structural characterization and Mössbauer study of LnV{sub 0.5}Fe{sub 0.5}O{sub 3} perovskites (Ln = Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho and Er)

    Energy Technology Data Exchange (ETDEWEB)

    Ivashita, Flávio F.; Biondo, Valdecir; Bellini, Jusmar V.; Paesano, Andrea [Departamento de Física, Universidade Estadual de Maringá, Av. Colombo 5790, 87.020-900 Maringá, PR (Brazil); Blanco, M. Cecilia; Fuertes, Valeria C.; Pannunzio-Miner, Elisa V. [INFIQC-CONICET, Departamento de Fisicoquímica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA Córdoba (Argentina); Carbonio, Raúl E., E-mail: carbonio@fcq.unc.edu.ar [INFIQC-CONICET, Departamento de Fisicoquímica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA Córdoba (Argentina)

    2012-09-15

    Graphical abstract: Mössbauer spectra taken at 200 K for the Y(V{sub 0.5}Fe{sub 0.5})O{sub 3} orthoferrivanadate synthesized by arc-melting. Highlights: ► LnFe{sub 0.5}V{sub 0.5}O{sub 3} were synthesized by the first time for most of the rare-earth elements. ► These orthoferrivanadates crystallize metastably with the perovskite structure. ► Iron and vanadium are trivalent stabilized in these solid solutions. ► The Mössbauer quadrupolar splitting is correlated with the tolerance factor. ► Below 100 K, these perovskites undergo a crystallographic phase transformation. -- Abstract: Perovskites LnV{sub 0.5}Fe{sub 0.5}O{sub 3} (Ln = Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho and Er) were synthesized by rapid solidification from arc-melted samples and characterized by the study of their crystal structure and hyperfine properties. These metastable solid solutions crystallized in the Pbnm symmetry, with the iron and vanadium cations randomly distributed in the transition metal octahedral sites. Depending on the lanthanide present at the A site of the perovskite, iron is present with two valences (i.e., Fe{sup 3+} and Fe{sup 2+}). The volume of the unit cell for these perovskites increases linearly with the lanthanide ionic radius, as the perovskite approaches its ideal structure. At room temperature, the quadrupolar splitting of the trivalent paramagnetic Mössbauer component works as an indirect measurement for the Goldshmidt tolerance factor. Close to or below 100 K, these perovskites undergo a crystallographic phase transformation, probably due to orbital ordering of the V{sup 3+} cations, originating two different magnetic iron sites.

  11. Magnetocaloric effects of binary rare earth mononitrides, Gd {sub x}Tb{sub 1-x}N and Tb {sub x}Ho{sub 1-x}N

    Energy Technology Data Exchange (ETDEWEB)

    Nakagawa, Takashi [Department of Nuclear Engineering, Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka 565-0871 (Japan)]. E-mail: nakagawa@mit.eng.osaka-u.ac.jp; Sako, Kengo [Department of Nuclear Engineering, Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka 565-0871 (Japan); Arakawa, Takayuki [Department of Nuclear Engineering, Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka 565-0871 (Japan); Tomioka, Naoto [Department of Nuclear Engineering, Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka 565-0871 (Japan); Yamamoto, Takao A. [Department of Nuclear Engineering, Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka 565-0871 (Japan); Kamiya, Koji [Tsukuba Magnet Laboratory, National Institute for Materials Science, Tsukuba, Ibaraki 305-0003 (Japan); Numazawa, Takenori [Tsukuba Magnet Laboratory, National Institute for Materials Science, Tsukuba, Ibaraki 305-0003 (Japan)

    2006-02-09

    We have synthesized Gd {sub x}Tb{sub 1-x}N and Tb {sub x}Ho{sub 1-x}N (x = 0, 0.25, 0.5, 0.75 and 1) by the carbothermic reduction performed in a nitrogen gas stream. GdN and TbN have been completely miscible with each other as well as TbN and HoN. As x was changed from 0 to 1, the Curie temperature increased monotonously from 18.5 to 43.8 K for Tb {sub x}Ho{sub 1-x}N and from 43.8 to 61.2 K for Gd {sub x}Tb{sub 1-x}N. The magnetocaloric effects have been evaluated by calculating the magnetic entropy changes from the magnetization data sets measured at different applied fields and temperatures. In any composition x, the magnetocaloric effects of Gd {sub x}Tb{sub 1-x}N and Tb {sub x}Ho{sub 1-x}N are larger than those of Gd {sub x}Dy{sub 1-x}N. Therefore, Gd {sub x}Tb{sub 1-x}N and Tb {sub x}Ho{sub 1-x}N are promising magnetic refrigerant materials for hydrogen liquefying system working below liquid nitrogen temperature.

  12. Magnetic behaviour of Tb impurities in Gd andY single crystals: a nuclear orientation study

    Science.gov (United States)

    Trhlík, M.; Brewer, W. D.; Kuriplach, J.; Sedlák, B.; Dupák, J.

    1993-03-01

    The low temperature nuclear orientation of160Tb impurities in Gd andY single crystals has been studied in the temperature range 7 40 mK andin the external magnetic field range 0 7.3 T applied along a-, b- and c-crystal axes. In the case of Tb in Gd we found a considerable noncollinearity of the Tb magnetic moment with respect to the magnetic external field direction even for high B ext. In the case of Tb in Y the results cannot be described by a simple model, taking into account the simultaneous influence of the crystal andexternal magnetic fields. Some new proposals for interpretation of the experimental dat are given.

  13. Magnetocaloric effect of Gd-Tb alloys: influence of the sample shape anisotropy

    Czech Academy of Sciences Publication Activity Database

    Kaštil, J.; Javorský, J.; Kamarád, Jiří; Šantavá, Eva

    2011-01-01

    Roč. 104, č. 1 (2011), s. 205-209 ISSN 0947-8396 R&D Projects: GA ČR GA202/09/0030 Institutional research plan: CEZ:AV0Z10100521 Keywords : magnetic refrigeration * magnetization * specific heat * magnetocaloric effect * Gd-Tb alloy * shape anisotropy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.630, year: 2011

  14. Electrical characteristics of hybrid detector based Gd2O2S:Tb-Selenium for digital radiation imaging

    International Nuclear Information System (INIS)

    Kang, Sang-Sik; Park, Ji-Koon; Choi, Jang-Yong; Cha, Byung-Yul; Cho, Sung-Ho; Nam, Sang-Hee

    2005-01-01

    Fine Gd 2 O 2 S:Tb powders were synthesized by using a solution-combustion method for a high-resolution digital X-ray imaging detector. The PL spectrum showed that the phosphor was fully crystallized and that the Tb 3+ ions substituted well for the Gd 3+ sites. To investigate the X-ray response of the phosphor, a uniform Gd 2 O 2 S:Tb film was grown using a screen-printing method. The X-ray sensitivities of the 100 μm-Gd 2 O 2 S:Tb/30 μm -Se and 200 μm -Se detector were 470 and 420 pC/cm 2 /mR, respectively, at an electric field of 10 V/μm. The results of the study suggest that the hybrid detector has a significant potential in the application of digital radiography and fluoroscopy systems

  15. Perpendicular exchange coupling effects in ferrimagnetic TbFeCo/GdFeCo hard/soft structures

    Science.gov (United States)

    Wang, Ke; Wang, Yahong; Ling, Fujin; Xu, Zhan

    2018-04-01

    Bilayers consisting of magnetically hard TbFeCo and soft GdFeCo alloy were fabricated. Exchange-spring and sharp switching in a step-by-step fashion were observed in the TbFeCo/GdFeCo hard/soft bilayers with increasing GdFeCo thickness. A perpendicular exchange bias field of several hundred Oersteds is observed from the shift of minor loops pinned by TbFeCo layer. The perpendicular exchange energy is derived to be in the range of 0.18-0.30 erg/cm2. The exchange energy is shown to increase with the thickness of GdFeCo layer in the bilayers, which can be attributed to the enhanced perpendicular anisotropy of GdFeCo layer in our experimental range.

  16. Cooperative upconversion luminescence of Er3 + in Gd2O3 - xSx phosphor

    Science.gov (United States)

    Wang, Fei; Yang, Bin; Yu, Qingchun; Liu, Dachun; Ma, Wenhui

    2018-02-01

    Gd2O3 - xSx:Er crystals were prepared through high-temperature solid-state reaction method in vacuum, with the vacuum synthesis mechanism determined by thermal analysis. The crystal structure and upconversion luminescence properties were investigated respectively by XRD, TEM and spectrophotometer. Well crystallized Gd2O2S:Er phosphors were prepared under 1000 °C in vacuum with a certain excessive amount of sulfur content than stoichiometric. It is confirmed that with the increasing sulfur content the green emission was enhanced and red emission was weakened. The cooperative upconversion luminescence of Er3 + in non-stoichiometric Gd2O3 - xSx crystals was interpreted as a result of two photon absorption and the photon avalanche process.

  17. Magnetic behavior of metallic kagome lattices, Tb3Ru4Al12 and Er3Ru4Al12

    Science.gov (United States)

    Upadhyay, Sanjay Kumar; Iyer, Kartik K.; Sampathkumaran, E. V.

    2017-08-01

    We report the magnetic behavior of two intermetallic-based kagome lattices, Tb3Ru4Al12 and Er3Ru4Al12, crystallizing in the Gd3Ru4Al2-type hexagonal crystal structure, by measurements in the range 1.8-300 K with bulk experimental techniques (ac and dc magnetization, heat capacity, and magnetoresistance). The main finding is that the Tb compound, known to order antiferromagnetically below (T N =) 22 K, shows glassy characteristics at lower temperatures (\\ll 15 K), thus characterizing this compound as a re-entrant spin-glass. The data reveal that the glassy phase is quite complex and is of a cluster type. Since glassy behavior was not seen for the Gd analog in the past literature, this finding on the Tb compound emphasizes that this kagome family could provide an opportunity to explore the role of higher-order interactions (such as quadrupole) in bringing out magnetic frustration. Additional findings reported here for this compound are: (i) The plots of temperature dependence of magnetic susceptibility and electrical resistivity data in the range 12-20 K, just below T N , are found to be hysteretic leading to a magnetic phase in this intermediate temperature range, mimicking disorder-broadened first-order magnetic phase transitions; (ii) features attributable to an interesting magnetic phase co-existence phenomenon in the isothermal magnetoresistance in zero field, after travelling across metamagnetic transition fields, are observed. With respect to the Er compound, we do not find any evidence for long-range magnetic ordering down to 2 K, but this compound appears to be on the verge of magnetic order at 2 K.

  18. The normal and inverse magnetocaloric effect in RCu2 (R=Tb, Dy, Ho, Er) compounds

    International Nuclear Information System (INIS)

    Zheng, X.Q.; Xu, Z.Y.; Zhang, B.; Hu, F.X.; Shen, B.G.

    2017-01-01

    Orthorhombic polycrystalline RCu 2 (R=Tb, Dy, Ho and Er) compounds were synthesized and the magnetic properties and magnetocaloric effect (MCE) were investigated in detail. All of the RCu 2 compounds are antiferromagnetic (AFM) ordered. As temperature increases, RCu 2 compounds undergo an AFM to AFM transition at T t and an AFM to paramagnetic (PM) transition at T N . Besides of the normal MCE around T N , large inverse MCE around T t was found in TbCu 2 compound. Under a field change of 0–7 T, the maximal value of inverse MCE is even larger than the value of normal MCE around T N for TbCu 2 compound. Considering of the normal and inverse MCE, TbCu 2 shows the largest refrigerant capacity among the RCu 2 (R=Tb, Dy, Ho and Er) compounds indicating its potential applications in low temperature multistage refrigeration. - Highlights: • Large inverse magnetocaloric effect is observed in TbCu 2 compound. • The AFM to AFM transition is observed in RCu 2 (R=Tb, Dy, Ho, Er) compounds. • The MCE performance of TbCu 2 compound is evaluated in a more comprehensively way.

  19. Magnetic structures in RNi₄B (R=Nd, Tb, Ho, Er)

    Energy Technology Data Exchange (ETDEWEB)

    Alleno, E., E-mail: eric.alleno@icmpe.cnrs.fr [ICMPE, UMR 7182 CNRS-UPEC, 2 rue Henri Dunant, 94320 Thiais (France); Mazumdar, C. [Saha Institute of Nuclear Physics, Sector-1, Block-AF, 700064 Kolkata (India)

    2013-06-01

    Neutron diffraction has been performed on RNi₄B (R=Nd, Tb, Ho, Er) polycrystals. The orthorhombic structure for NdNi₄B and the CeCo₄B structure type (hexagonal) for TbNi₄B and HoNi₄B are confirmed. Our data also show that this last structure is currently the best approximant for ErNi₄B. The RNi₄B (R=Nd, Tb, Ho, Er) order ferromagnetically at respectively 11.0, 18.1, 6.2 and 10.0 K. The crystal electric field (CEF) interaction controls the magnetic anisotropy in this series leading to an easy axis ~30 deg above the basal plane in RNi₄B (R=Nd, Tb, Ho) and parallel to the c-axis in ErNi₄B at 1.6 K. The RNi₄B (R=Nd, Tb, Ho) display a spin re-orientation below Tc which arises from a competition between the second order term and the higher order terms of the CEF hamiltonian. - Graphical abstract: Simplified magnetic structure in NdNi₄B and full magnetic structure in RNi₄B (R=Tb, Ho). Variation with temperature of the easy magnetization axis direction (angle with c-axis) showing a spin re-orientation. Highlights: • RNi₄B (R=Nd, Tb, Ho, Er) polycrystals were inductively melted. • Neutron diffraction confirms they all order ferromagnetically. • The magnetization easy axis is parallel to the c-axis in ErNi₄B. • The RNi₄B (R=Nd, Tb, Ho) display a spin re-orientation below Tc. • Their easy axis tilts from the c-axis at Tc to ~30 deg above the basal plane at 1.5 K.

  20. Electronic and Spectral Properties of RRhSn (R = Gd, Tb) Intermetallic Compounds

    Science.gov (United States)

    Knyazev, Yu. V.; Lukoyanov, A. V.; Kuz'min, Yu. I.; Gupta, S.; Suresh, K. G.

    2018-02-01

    The investigations of electronic structure and optical properties of GdRhSn and TbRhSn were carried out. The calculations of band spectrum, taking into account the spin polarization, were performed in a local electron density approximation with a correction for strong correlation effects in 4f shell of rare earth metal (LSDA + U method). The optical studies were done by ellipsometry in a wide range of wavelengths, and the set of spectral and electronic characteristics was determined. It was shown that optical absorption in a region of interband transitions has a satisfactory explanation within a scope of calculations of density of electronic states carried out.

  1. Magnetic properties of the filled skutterudite-type structure compounds GdRu4P12 and TbRu4P12 synthesized under high pressure

    OpenAIRE

    Sekine, C; Uchiumi, T; Shirotani, I; Matsuhira, kazuyuki; Sakakibara, T; Goto, T; Yagi, T

    2000-01-01

    We have succeeded in synthesizing filled skutterudite-type structure compounds GdRu4P12 and TbRu4P12 under high pressure. The magnetic properties of GdRu4P12 and TbRu4P12 have been studied by means of electrical resistivity, magnetic susceptibility, and magnetization measurements. Magnetic experiments suggest that the Gd and Tb ions in the compounds have trivalent state. The compound GdRu4P12 displays features that suggest the occurrence of antiferromagnetic ordering below TN=22 K. In TbRu4P1...

  2. Bimodal Fluorescence and Magnetic Resonance Imaging Using Water-Soluble Hexagonal NaYF4:Ce,Tb,Gd Nanocrystals

    Directory of Open Access Journals (Sweden)

    Wen Ting Ren

    2011-01-01

    Full Text Available The present study explored the feasibility of using hexagonal-phase NaYF4:Ce,Tb,Gd nanocrystals as bimodal probes for fluorescence and magnetic resonance (MR imaging. Using a facile and user-friendly strategy, the NaYF4:Ce,Tb,Gd nanocrystals were synthesized with good water dispensability, high quantum yield (26%, and decent MR T1 relaxivity (r1=2.87 mM−1 s−1. The NaYF4:Ce,Tb,Gd NCs conjugated by folic acid presented great efficiency in fluorescence imaging of C6 glioma cells in vitro. Meanwhile, in in vivo MR experiments on rats, the NaYF4:Ce,Tb,Gd NCs also significantly increased T1 signal in the liver, spleen, and kidney even with a low probe dose. The proposed NaYF4:Ce,Tb,Gd nanoprobes hold promise for simultaneous bimodal fluorescence and MR bioimaging.

  3. Phase transformations and indications for acoustic mode softening in Tb-Gd orthophosphate.

    Science.gov (United States)

    Tschauner, O; Ushakov, S V; Navrotsky, A; Boatner, L A

    2016-01-27

    At ambient conditions the anhydrous rare earth orthophosphates assume either the xenotime (zircon) or the monazite structure, with the latter favored for the heavier rare earths and by increasing pressure. Tb0.5Gd0.5PO4 assumes the xenotime structure at ambient conditions but is at the border between the xenotime and monazite structures. Here we show that, at high pressure, Tb0.5Gd0.5PO4 does not transform directly to monazite but through an intermediate anhydrite-type structure. Axial deformation of the unit cell near the anhydrite- to monazite-type transition indicates softening of the (c1133  +  c1313) combined elastic moduli. Stress response of rare-earth orthophosphate ceramics can be affected by both formation of the anhydrite-type phase and the elastic softening in the vicinity of the monazite-phase. We report the first structural data for an anhydrite-type rare earth orthophosphate.

  4. X-ray excited photoluminescence near the giant resonance in solid-solution Gd(1-x)Tb(x)OCl nanocrystals and their retention upon solvothermal topotactic transformation to Gd(1-x)Tb(x)F3.

    Science.gov (United States)

    Waetzig, Gregory R; Horrocks, Gregory A; Jude, Joshua W; Zuin, Lucia; Banerjee, Sarbajit

    2016-01-14

    Design rules for X-ray phosphors are much less established as compared to their optically stimulated counterparts owing to the absence of a detailed understanding of sensitization mechanisms, activation pathways and recombination channels upon high-energy excitation. Here, we demonstrate a pronounced modulation of the X-ray excited photoluminescence of Tb(3+) centers upon excitation in proximity to the giant resonance of the host Gd(3+) ions in solid-solution Gd1-xTbxOCl nanocrystals prepared by a non-hydrolytic cross-coupling method. The strong suppression of X-ray excited optical luminescence at the giant resonance suggests a change in mechanism from multiple exciton generation to single thermal exciton formation and Auger decay processes. The solid-solution Gd1-xTbxOCl nanocrystals are further topotactically transformed with retention of a nine-coordinated cation environment to solid-solution Gd1-xTbxF3 nanocrystals upon solvothermal treatment with XeF2. The metastable hexagonal phase of GdF3 can be stabilized at room temperature through this topotactic approach and is transformed subsequently to the orthorhombic phase. The fluoride nanocrystals indicate an analogous but blue-shifted modulation of the X-ray excited optical luminescence of the Tb(3+) centers upon X-ray excitation near the giant resonance of the host Gd(3+) ions.

  5. Crystal fields of dilute Tb, Dy, or Er in Sc obtained by magnetization measurements

    DEFF Research Database (Denmark)

    Høg, J.; Touborg, P.

    1976-01-01

    Crystal-field parameters for dilute Sc-Tb, Sc-Dy, and Sc-Er alloys have been obtained by fitting theoretical expressions to the experimentally measured paramagnetic susceptibility. The initial susceptibility was measured and corrected for the effects of ordering at the lowest temperatures...

  6. Spectroscopic properties of transparent Er-doped oxyfluoride glass-ceramics with GdF₃.

    Science.gov (United States)

    Środa, Marcin; Szlósarczyk, Krzysztof; Różański, Marek; Sitarz, Maciej; Jeleń, Piotr

    2015-01-05

    Optically active glass-ceramics (GC) with the low-phonon phases of fluorides, doped with Er(3+) was studied. Glass based on SiO₂-Al₂O₃-Na₂F₂-Na₂O-GdF₃-BaO system was obtained. Dopant were introduced to the glass in an amount of 0.01 mol Er₂O₃ per 1 mol of glass. DTA/DSC study shows multi-stage crystallization. XRD identification of obtained phases did not confirm the presence of pure GdF₃ phase. Instead of that ceramization process led to formation of NaGdF₄ and BaGdF₅. The structural changes were studied using FT-IR spectroscopic method. The study of luminescence of the samples confirmed that optical properties of the obtained GC depend on crystallizing phases during ceramization. Time resolved spectroscopy of Er-doped glass showed the 3 and 8 times increase of lifetime of emission from (4)S₃/₂ and (4)F₉/₂ states, respectively. It confirms the erbium ions have ability to locate in the low phonon gadolinium-based crystallites. The results give possibility to obtain a new material for optoelectronic application. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Luminescence, Energy Transfer and Tunable Color of Ce3+- and Tb3+-Activated Na3Gd(BO3)2 Phosphors

    Science.gov (United States)

    Zhang, Xinguo; Pan, Jialiang; Mo, Fuwang

    2017-07-01

    A series of blue Na3Gd(BO3)2:Ce3+ and blue-to-green color-tunable Na3Gd (BO3)2:Ce3+,Tb3+ phosphors were synthesized by the solid-state method. The luminescence, concentration quenching and energy transfer (ET) process of Na3Gd(BO3)2:Ce3+,Tb3+ were investigated. Both Ce3+ and Tb3+ occupy the Gd3+ site in the Na3Gd(BO3)2 host. Na3Gd(BO3)2:Ce3+ exhibits strong ultraviolet absorption and broadband blue emission. The Ce3+ sensitization effect on Tb3+ has been verified by the variation of PL/PLE spectra, the Ce3+ decay lifetimes and the energy transfer efficiency of Na3Gd(BO3)2:Ce3+,Tb3+ phosphors. The maximum Ce3+-Tb3+ ET efficiency has been calculated to be 95%. The emitting color of the obtained phosphors can be modulated from blue (0.179, 0.204) through bluish-green (0.271, 0.391) to green (0.349, 0.551) by properly changing the ratio of Ce3+/Tb3+.

  8. Efficient three-photon luminescence with strong polarization dependence from a scintillating silicate glass co-doped with Gd3+ and Tb3+.

    Science.gov (United States)

    Li, Guang-Can; Zhang, Cheng-Yun; Deng, Hai-Dong; Liu, Guang-Yin; Lan, Sheng; Qian, Qi-; Yang, Zhong-Min; Gopal, Achanta Venu

    2013-03-11

    Efficient three-photon luminescence (3PL) from a scintillating silicate glass co-doped with Gd(3+) and Tb(3+) was generated by using a focused femtosecond laser beam at 800 nm. Four emission bands centered at 496, 541, 583, and 620 nm were identified as the electronic transitions between the energy levels of Tb(3+) followed by three-photon absorption (3PA) in Gd(3+) and Tb(3+) and the resonant energy transfer from Gd(3+) to Tb(3+). More interestingly, a strong polarization dependence of the 3PL was observed and it is ascribed to the polarization dependent 3PA in Gd(3+) and Tb(3+) and/or the angular distribution of photogenerated electrons in the glass.

  9. The development of new phosphors of Tb3+/Eu3+ co-doped Gd3Al5O12 with tunable emission

    Science.gov (United States)

    Teng, Xin; Wang, Wenzhi; Cao, Zhentao; Li, Jinkai; Duan, Guangbin; Liu, Zongming

    2017-07-01

    The gadolinium aluminum garnets Gd3Al5O12 (GdAG) activated with Tb3+/Eu3+ were successfully prepared via co-precipitation method at 1500 °C in this work. The crystal structure stabilization, elements analysis, microphotograph, PL/PLE spectra, decay behavior and quantum efficiency were discussed in detail. The metastable GdAG compounds been effectively stabilized by doping with smaller 10 at.% Tb3+, which then allows the development of new phosphors of (Gd0.9-xTb0.1Eux)3Al5O12 (GdAG:Tb3+/Eu3+, x = 0-0.03) for opto-functionality explorations. The PLE/PL spectra displays that the strongest PLE peak was located at ∼276 nm, which overlaps the 8S7/2 → 6IJ transition of Gd3+. Under 276 nm excitation, the phosphors exhibited both Tb3+ and Eu3+ emissions at 548 nm (green, 5D4 → 7F5 transition of Tb3+) and 592 nm (orange-red, 5D0 → 7F1 transition of Eu3+), respectively. The emission intensities of Tb3+ and Eu3+ remarkably varied with the Eu3+ incorporation. As a consequence, the emission color can be readily tuned from approximately green to orange-red. Fluorescence decay analysis found that the lifetime for the Tb3+ emission rapidly decreased conforming to the Tb3+ → Eu3+ energy transfer, and the energy transfer efficiency was calculated. Owing to the Gd3+ → Eu3+ and Gd3+ → Tb3+ energy transfer, the emission intensities of Tb3+ and Eu3+ in (Gd0.9-xTb0.1Eux)AG phosphor were higher than (Y0.87Tb0.1Eu0.03)AG and (Lu0.87Tb0.1Eu0.03)AG system. The (Gd0.9-xTb0.1Eux)AG garnet phosphors developed in this work may serve as a new type of phosphor which hopefully meets the requirements of various lighting and optical display applications.

  10. Electron-hole recombination luminescence in LiYF4:U4+; Eu3+;Tb3+; Gd3+

    International Nuclear Information System (INIS)

    Page, A.G.; Godbole, S.V.; Sastry, M.D.; Sabharwal, S.C.

    2001-01-01

    Photoluminescence, photostimulated luminescence and electron paramagnetic resonance studies were carried out on LiYF 4 and LiYF 4 :U 4+ doped crystals. These investigations have identified presence of Eu 3+ , Tb 3+ and Gd 3+ ions being present in both the crystals arising due to their presence in starting material. On gamma irradiation, U 4+ ions were acting as electron trapping centre, and are responsible in introducing shallow traps in the material. In electron-hole recombination process, Tb 3+ ions were observed to be acting as luminescent centres. (author)

  11. High pressure neutron diffraction studies of the magnetic structures of Tb, Ho and Er

    International Nuclear Information System (INIS)

    Kawano, Shinji; Achiwa, Norio; Onodera, Akifumi; Nakai, Yutaka; Lebech, Bente.

    1993-01-01

    Pressure effects of the magnetic structures of Tb, Ho and Er have been studied by neutron diffraction using a newly-developed clamp type pressure cell. For Tb the pressure dependence of the turn angle in a helical phase shows an enhancement of its value, particularly in low temperatures with increasing pressure but no lock-in feature. Linear coefficients of the magnetic transition temperatures to pressure are obtained. For Ho the turn angle is increased by pressure and shows an almost linear temperature dependence at high temperatures and lock-in features at low temperatures. For Er the high pressure results reveal that the transition to a conical structure at low temperatures is suppressed and that a cycloidal structure with a modulation vector Q = 2/7(2π/c) persists down to 4.5 K, similar to a three up four down structure in Tm. (author)

  12. Polarized spectroscopic properties of Er3+:Gd2SiO5 crystal and evaluation of Er3+:Yb3+:Gd2SiO5 crystal as a 1.55 μm laser medium

    International Nuclear Information System (INIS)

    Wang, H.; Huang, J.H.; Gong, X.H.; Chen, Y.J.; Lin, Y.F.; Luo, Z.D.; Huang, Y.D.

    2016-01-01

    An Er 3+ -doped Gd 2 SiO 5 single crystal with high optical quality has been grown by the Czochralski method. Polarized absorption and fluorescence spectra and fluorescence lifetime of the crystal were measured at room temperature. Intensity parameters, spontaneous emission probabilities, fluorescence branching ratios, and radiative lifetimes were estimated on the basis of the Judd–Ofelt theory. Besides, potentiality of 1.55 μm laser emission in an Er 3+ –Yb 3+ co-doped Gd 2 SiO 5 crystal was evaluated.

  13. A2TiO5 (A = Dy, Gd, Er, and Yb) at high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sulgiye; Rittman, Dylan; Tracy, Cameron L.; Chapman, Karena W.; Zhang, Fuxiang; Park, Changyong; Tkachev, Sergey N.; O' Quinn, Eric; Shamblin, Jacob; Lang, Maik; Mao, Wendy L.; Ewing, Rodney C.

    2018-02-01

    The structural evolution of lanthanide A2TiO5 (A = Dy, Gd, Yb, and Er) at high pressure is investigated using synchrotron X-ray diffraction. The effects of A-site cation size and of the initial structure are systematically examined by varying the composition of the isostructural lanthanide titanates, and the structure of dysprosium titanate polymorphs (orthorhombic, hexagonal and cubic), respectively. All samples undergo irreversible high pressure phase transformations, but with different onset pressures depending on the initial structure. While individual phase exhibits different phase transformation histories, all samples commonly experience a sluggish transformation to a defect cotunnite-like (Pnma) phase for a certain pressure range. Orthorhombic Dy2TiO5 and Gd2TiO5 form P21am at pressures below 9 GPa and Pnma above 13 GPa. Pyrochlore-type Dy2TiO5 and Er2TiO5 as well as defect-fluorite-type Yb2TiO5 form Pnma at ~ 21 GPa, followed by Im-3m. Hexagonal Dy2TiO5 forms Pnma directly, although a small amount of remnants of hexagonal Dy2TiO5 is observed even at the highest pressure (~ 55 GPa) reached, indicating a kinetic limitations in the hexagonal Dy2TiO5 phase transformations at high pressure. Decompression of these materials leads to different metastable phases. Most interestingly, a high pressure cubic X-type phase (Im-3m) is confirmed using highresolution transmission electron microscopy on recovered pyrochlore-type Er2TiO5. The kinetic constraints on this metastable phase yield a mixture of both the X-type phase and amorphous domains upon pressure release. This is the first observation of an X-type phase for an A2BO5 composition at high pressure.

  14. Magnetism of manganese in RMn sub 2 and RMn sub 4 Al sub 8 (R=Y, Gd, Er) intermetallics

    CERN Document Server

    Talik, E; Winiarski, A; Neumann, M; Mydlarz, T; Gilewski, A; Böhm, H

    1998-01-01

    The XPS electronic structure was measured for YMn sub 2 , GdMn sub 2 , ErMn sub 2 , YMn sub 4 Al sub 8 and GdMn sub 4 Al sub 8 single crystals and pure Mn. Exchange splitting of Mn 3d and 3s states was found for the compounds with magnetic manganese. The electrical resistivity of the GdMn sub 2 single crystal shows an antiferromagnetic transition at 108 K and the second transition at 32 K. The lattice parameter against temperature of GdMn sub 2 exhibits a large spontaneous magnetostriction at T sub N. The anisotropic character of the GdMn sub 2 magnetization was found. The results were discussed using the Yamada and Shimizu model. (author)

  15. Luminescent properties of (Y,Gd)BO3:Bi3+,RE3+ (RE=Eu, Tb) phosphor under VUV/UV excitation

    International Nuclear Information System (INIS)

    Zeng Xiaoqing; Im, Seoung-Jae; Jang, Sang-Hun; Kim, Young-Mo; Park, Hyoung-Bin; Son, Seung-Hyun; Hatanaka, Hidekazu; Kim, Gi-Young; Kim, Seul-Gi

    2006-01-01

    Bi 3+ - and RE 3+ -co-doped (Y,Gd)BO 3 phosphors were prepared and their luminescent properties under vacuum ultraviolet (VUV)/UV excitation were investigated. Strong red emission for (Y,Gd)BO 3 :Bi 3+ ,Eu 3+ and strong green emission for (Y,Gd)BO 3 :Bi 3+ ,Tb 3+ are observed under VUV excitation from 147 to 200 nm with a much broader excitation region than that of single Eu 3+ -doped or Tb 3+ -doped (Y,Gd)BO 3 phosphor. Strong emissions are also observed under UV excitation around 265 nm where as nearly no luminescence is observed for single Eu 3+ -doped or Tb 3+ -doped (Y,Gd)BO 3 . The luminescence enhancement of Bi 3+ - and RE 3+ -co-doped (Y,Gd)BO 3 phosphors is due to energy transfer from Bi 3+ ion to Eu 3+ or Tb 3+ ion not only in the VUV region but also in the UV region. Besides, host sensitization competition between Bi 3+ and Eu 3+ or Tb 3+ is also observed. The investigated phosphors may be preferable for devices with a VUV light 147-200 nm as an excitation source such as PDP or mercury-free fluorescent lamp

  16. Theoretical investigations on the magnetocaloric and barocaloric effects in Tb{sub y}Gd{sub (1−y)}Al{sub 2} series

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, P.O.; Alho, B.P.; Alvarenga, T.S.T.; Nóbrega, E.P. [Instituto de Física, Universidade do Estado do Rio de Janeiro – UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil); Carvalho, A.Magnus G. [Instituto de Ciência e Tecnologia, Universidade Federal de São Paulo – UNIFESP, 12231-280 São José dos Campos, SP (Brazil); Instituto Nacional de Metrologia, Qualidade e Tecnologia – INMETRO, 25250-020 Duque de Caxias, RJ (Brazil); Sousa, V.S.R. de; Caldas, A.; Oliveira, N.A. de [Instituto de Física, Universidade do Estado do Rio de Janeiro – UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil); Ranke, P.J. von, E-mail: von.ranke@uol.com.br [Instituto de Física, Universidade do Estado do Rio de Janeiro – UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil)

    2013-06-25

    Highlights: ► Anisotropic magnetocaloric effect in in Tb{sub 0.4}Gd{sub 0.6}Al{sub 2}. ► Prediction of barocaloric effect in Tb{sub 0.4}Gd{sub 0.6}Al{sub 2}. ►An optimal hybrid magnetocaloric material using Tb{sub y}Gd{sub (1-y)}Al{sub 2} compounds. -- Abstract: We report the calculations on the magnetocaloric and barocaloric effects in ferromagnetic series Tb{sub y}Gd{sub (1−y)}Al{sub 2}. Our model includes the crystalline electrical field interaction, exchange interactions among Tb–Tb, Gd–Gd and Tb–Gd magnetic ions and the Zeeman effect for an anisotropic system. The lattice and electronic entropies were included in adiabatic processes. The magnetocaloric effect calculated for magnetic field changes along the easy magnetic direction 〈1 1 1〉 is in good agreement with the experimental data. Calculation along the hard magnetization direction 〈0 0 1〉 predicts anomalous magnetocaloric effect, which was ascribed to the spin reorientation processes. From the available experimental data of Curie temperature dependence on pressure, the exchange model parameters were scaled and the barocaloric effect was calculated.

  17. The normal and inverse magnetocaloric effect in RCu{sub 2} (R=Tb, Dy, Ho, Er) compounds

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, X.Q., E-mail: zhengxq@ustb.edu.cn [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Xu, Z.Y. [National Institute of Metrology, Beijing 100029 (China); Zhang, B.; Hu, F.X. [State Key Laboratory for Magnetism, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Shen, B.G., E-mail: shenbg@aphy.iphy.ac.cn [State Key Laboratory for Magnetism, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

    2017-01-01

    Orthorhombic polycrystalline RCu{sub 2} (R=Tb, Dy, Ho and Er) compounds were synthesized and the magnetic properties and magnetocaloric effect (MCE) were investigated in detail. All of the RCu{sub 2} compounds are antiferromagnetic (AFM) ordered. As temperature increases, RCu{sub 2} compounds undergo an AFM to AFM transition at T{sub t} and an AFM to paramagnetic (PM) transition at T{sub N}. Besides of the normal MCE around T{sub N}, large inverse MCE around T{sub t} was found in TbCu{sub 2} compound. Under a field change of 0–7 T, the maximal value of inverse MCE is even larger than the value of normal MCE around T{sub N} for TbCu{sub 2} compound. Considering of the normal and inverse MCE, TbCu{sub 2} shows the largest refrigerant capacity among the RCu{sub 2} (R=Tb, Dy, Ho and Er) compounds indicating its potential applications in low temperature multistage refrigeration. - Highlights: • Large inverse magnetocaloric effect is observed in TbCu{sub 2} compound. • The AFM to AFM transition is observed in RCu{sub 2} (R=Tb, Dy, Ho, Er) compounds. • The MCE performance of TbCu{sub 2} compound is evaluated in a more comprehensively way.

  18. Enhanced luminescence of rare-earth Tb (III obtained by mixing of Gd (III in a fumarate complex and intra-molecular energy transfer

    Directory of Open Access Journals (Sweden)

    Shah M.D.

    2015-12-01

    Full Text Available Trivalent lanthanide ions display fascinating optical properties. Therefore, the rare-earth complexes of terbium fumarate heptahydrate and GdTb fumarate heptahydrate were grown by using a single gel diffusion technique. The crystals were characterized by different physicochemical techniques of characterization. UV-Vis and photoluminescence spectrophotometric experiments were carried out to study the optical properties of the grown crystals. Under various excitations (339 nm, 350 nm or 368 nm the terbium fumarate complex emitted characteristic (4f-4f green emission of Tb3+ (5D4-7FJ, J = 6, 5, 4 and 3, respectively. Luminescence spectra showed that Gd3+ ions in the mixed complex have not affected the luminescence emission peak positions, but remarkably increased the luminescent intensities of the terbium complex. The energy-transfer mechanism between the ligand and the central Tb3+ ions and from the Gd3+ to the Tb3+ was discussed.

  19. Influence of Er(3+) concentration on the photoluminescence characteristics and excitation mechanism of Gd2O3:Er(3+) phosphor synthesized via a solid-state reaction method.

    Science.gov (United States)

    Tamrakar, R K; Bisen, D P; Bramhe, N

    2015-08-01

    An Er(3+) -doped phosphor of Gd2O3(Gd2O3:Er(3+)) was prepared using a conventional solid-state reaction method. The structure and particle size were determined from X-ray powder diffraction measurements. The average particle size of the phosphor was in between 20 and 50 nm. The particle size and structure of the phosphor were further confirmed by transmission electron microscopy (TEM) analysis. Luminescence spectra were recorded under excitation wavelengths of 275, 380, 515 and 980 nm. The visible upconversion and downconversion luminescence spectra of the Gd2O3:Er(3+) phosphor were investigated as a function of Er(3+) ion concentration. The upconverted emission at 980 nm excitation shows enhanced red emission with respect to green emission as the dopant concentration increased. Similar results were observed for downconversion emission under 275 and 380 nm excitation wavelengths. The mechanisms responsible for populating the (4)S3/2 and (4)F9/2 levels, for green and red emissions, respectively, are different for different excitations and for different concentrations of Er(3+). Copyright © 2014 John Wiley & Sons, Ltd.

  20. Hyperfine interaction studies of the perovskite oxides of the type RCrO3 (R = Gd, Tb e Dy)

    International Nuclear Information System (INIS)

    Silva, Renilson Adriano da

    2009-01-01

    ABO 3 perovskite oxides have ideal cubic structure, however, some distortions in this type of structure may induce changes from cubic to orthorhombic or rhombroedric symmetry. The larger atoms A are located at the center of a cube, the B atoms are on 8 vertices and oxygen atoms occupy 12 positions in the middle of each side of the cube. Distortions in this structure may lead to new magnetic and electrical properties, with great scientific and technological interest. In this work RCrO 3 (R = Gd, Tb, Dγ) compounds (also known as orthocromites) were studied. The samples were produced by means of sol-gel chemical procedure and analyzed by X-Ray Diffraction. The results showed a single phase with Pbnm space group. The perturbed gamma-gamma angular correlation (PAC) measurements were carried out using 181 Hf( 181 Ta) and 111 In( 111 Cd) nuclear probes, which substitute 'A' and 'B' positions respectively. The probe nuclei were introduced in the samples during the chemical procedures for preparation. One of the objectives of this work's was to study the hyperfine magnetic field and its variation as a function of temperature, crystallographic structure as well as the antiferromagnetic transition temperature (T N ). The PAC Measurements were carried out in the temperature range of 20 to 300 K for R = Gd, Tb and 20 to 800 K in the case of R = Dγ from. Electric field gradient was also measured as a function of temperature. It was possible to observe the expected transition as well as the alignment of Cr spins, as found in literature. The Neel temperatures (TN) for investigated samples are ∼170 K, ∼164 K and ∼148 K for GdCrO 3 , TbCrO 3 and DyCrO 3 respectively. (author)

  1. Thermodynamic studies on LnCoO{sub 3} (Ln = Eu, Gd, Tb) by solid-state electrochemical cells

    Energy Technology Data Exchange (ETDEWEB)

    Patil, Abhay; Dash, Smruti; Parida, S.C.; Venugopal, V

    2004-12-14

    Ternary oxides in the systems Ln-Co-O (where Ln = Eu, Gd, Tb) have been prepared by citrate-nitrate gel combustion method and characterized by X-ray powder diffraction method. Appropriate equilibrium phase mixtures were prepared, sintered in high purity argon gas and used for e.m.f. measurement using solid oxide galvanic cell with yttria-stabilized zirconia (YSZ) electrolyte. The e.m.f. values were measured as a function of temperature in the range of 1000-1200 K. The standard molar Gibbs energy of formation of the ternary oxides were calculated from the e.m.f. data.

  2. Investigation of local magnetism in RZn (R = Ce, Gd, Tb, Dy) and GdCu intermetallic compounds using perturbed angular correlation gamma-gamma spectroscopy

    International Nuclear Information System (INIS)

    Santos, Brianna Bosch dos

    2010-01-01

    This work presents, from a microscopic point of view, a systematic study of the local magnetism in RZn (R = Ce, Gd, Tb, Dy) and GdCu intermetallic compounds through measurements of hyperfine interactions using the Perturbed Angular Correlation Gamma- Gamma Spectroscopy technique with 111 In → 111 Cd and 140 La → 140 Ce as probe nuclei. As the magnetism in these compounds originates from the 4f electrons of the rare-earth elements it is interesting to observe in a systematic study of RZn compounds the behavior of the magnetic hyperfine field with the variation of the number of 4f electrons in the R element. The use of probe nuclei 140 La → 140 Ce is interesting because Ce +3 ion posses one 4f electron which may contribute to the total hyperfine field, and the results showed anomalous behavior. The results for 111 Cd probe showed that the temperature dependence of the magnetic hyperfine field follows the Brillouin function, and the magnetic hyperfine field decreases linearly with increase of the atomic number of rare earth when plotted as a function of the rare-earth J spin projection, showing that the main contribution to the magnetic hyperfine field in RZn compounds comes from the polarization of the conduction electrons. The results for the electric field gradient measured with 111 Cd for all compounds showed a strong decrease with the atomic number of the rare-earth element. We have therefore assumed that the major contribution to the electric field gradient originates from the 4f electrons of the rare-earths. The measurements of the electric field gradient for GdCu with 111 Cd, after temperature decreases and increases again showed that two different structures, CsCl-type cubic and FeB-type orthorhombic structures co-exist. Finally, it is the first time that measurements of hyperfine parameters have been carried out with theses two probe nuclei in the studied RZn. (author)

  3. Optical thermometry based on green upconversion emission in Er3+/Yb3+ codoped BaGdF5 glass ceramics

    Science.gov (United States)

    Wu, Ting; Zhao, Shilong; Lei, Ruoshan; Huang, Lihui; Xu, Shiqing

    2018-02-01

    Er3+/Yb3+ codoped BaGdF5 glass ceramics have been prepared and used to develop a portable all-fiber temperature sensor based on fluorescence intensity ratio technique. XRD and TEM results affirm the generation of BaGdF5 nanocrystals in the borosilicate glass. Eu3+ ions are used as spectral probe to investigate external environment around rare earth (RE) ions. Intense green upconversion emissions from Er3+ ions are detected in the BaGdF5 glass ceramics and their intensity are enhanced about three orders of magnitude after heat treatment, which is attributed to the enrichment of RE ions in the BaGdF5 phase. Based on green upconversion emission from Er3+ ions, the temperature sensing property of the portable all-fiber temperature sensor is studied. The maximum absolute sensitivity is 15.5 × 10‑4 K‑1 at 567 K and the relative sensitivity is 1.28% K‑1 at 298 K, respectively.

  4. Spin transfer torque switching in exchange-coupled amorphous GdFeCo/TbFe bilayers for thermally assisted MRAM application

    Science.gov (United States)

    Dai, Bing; Guo, Yong; Zhu, Jiaqi; Kato, Takeshi; Iwata, Satoshi; Tsunashima, Shigeru; Yang, Lei; Han, Jiecai

    2017-04-01

    Exchange-coupled amorphous GdFeCo/TbFe memory layers in giant magneto-resistance (GMR) devices for spin transfer torque (STT) switching have been studied, and temperature dependence of the critical current density of the GMR devices was measured to discuss the effect of exchange-coupled bilayers as a memory layer of the thermally assisted magnetic random access memory (MRAM). The GMR devices having amorphous GdFeCo and TbFe memory bilayers with various thicknesses were prepared by magnetron sputtering and subsequent micro-fabrication processes. A pulsed current was applied to the GMR devices in order to investigate the spin transfer torque (STT) switching. The maximum magneto-resistance (MR) ratio was around 0.15%, and the coercivity of the memory bilayer increased with the TbFe thickness and decreased with elevating temperature. The critical current densities J c to switch the memory bilayer with structure of Gd21.4 (Fe90Co10)78.6(9 nm)/Tb16Fe84 (1 nm) as low as 2.2  ×  107 A cm-2 was obtained. The J c reduced with increasing the temperature and was found to scale with the effective anisotropy K eff of GdFeCo/TbFe bilayer, which is believed to be suitable for the application of thermally assisted STT-MRAM.

  5. Lanthanide stannate pyrochlores (Ln2Sn2O7; Ln = Nd, Gd, Er) at high pressure.

    Science.gov (United States)

    Turner, Katlyn M; Tracy, Cameron L; Mao, Wendy L; Ewing, Rodney C

    2017-11-09

    Lanthanide stannate pyrochlores (Ln2Sn2O7; Ln=Nd, Gd, and Er) were investigated in situ to 50 GPa in order to determine their structural response to compression and compare it to that of lanthanide titanate, zirconate, and hafnate pyrochlores. The cation radius ratio of A3+/B4+ in pyrochlore oxides (A2B2O7) is thought to be the dominant property that influences their compression response. The ionic radius of Sn4+ is intermediate to that of Ti4+, Zr4+, and Hf4+, but the bond in stannate pyrochlore is more covalent than the bonds in titanates, zirconate, and hafnates. In stannates, the pyrochlore cation and anion sublattices begin to disorder at 0.3 GPa. The extent of sublattice disorder vs. pressure is greater in stannates with a smaller Ln3+ cation. Stannate pyrochlores (Fd-3m) begin a sluggish transformation to a cotunnite-like structure (Pnma) at ~28 GPa; similar transitions have been observed in titanate, zirconate, and hafnate pyrochlore at varying pressures with cation radius ratio. The extent of the phase transition vs. pressure varies directly with the size of the Ln3+ cation. Post-decompression from ~50 GPa, Er2Sn2O7 and Gd2Sn2O7 adopt a pyrochlore structure, rather than the multiscale defect-fluorite + weberite structure adopted by Nd2Sn2O7 that is characteristic of titanate, zirconate, and hafnate pyrochlore treated to similar conditions. Like pyrochlore titanates, zirconates, and hafnates, the bulk modulus, B0, of stannates varies linearly and inversely with cation radius ratio. The trends of bulk moduli in stannates in this study are in excellent agreement with previous experimental studies on stannates, and suggest that the size of the Ln3+ cation is a primary determining factor of B0. Additionally, when normalized to rA/rB, the bulk moduli of stannates are comparable to those of zirconates and hafnates, which vary from titanates. Our results suggest that the cation radius ratio strongly influences the bulk moduli of stannates as well as

  6. Near ultraviolet to near infrared luminescence spectroscopy of Er3+ doped K2GdF5 crystal

    International Nuclear Information System (INIS)

    Qin, Yanguang; Wei, Xiantao; Li, Xinyue; Chen, Yonghu; Yin, Min

    2014-01-01

    The detailed luminescent properties of K 2 GdF 5 crystal doped with Er 3+ was investigated using excitation spectra, emission spectra and emission decay curve measurements. The excitation bands corresponding to the characteristic Gd 3+ 4f–4f transitions in the excitation spectra of Er 3+ emission indicate an efficient energy transfer from host Gd 3+ to doping Er 3+ ions. Meanwhile, the distinct features observed only in the emission spectra excited with shorter wavelengths (≤312 nm) are assigned to the transitions from 2 P 3/2 levels of Er 3+ . This assignment is further supported by the decay curves measurements and the obtained lifetime of 2 P 3/2 emission (460 μs) is longer than that of 4 S 3/2 emission (248 μs). The luminescence in near infrared (NIR) range from 750 to 1650 nm consists of several well-distinguished bands dominated by the emission around 1540 nm corresponding to the transition of 4 I 13/2 → 4 I 15/2 . NIR quantum cutting processes are observed and discussed with reference to the NIR emission spectra. - Highlights: • Energy transfer from host Gd 3+ to doping Er 3+ ions is efficient. • The transitions from 2 P 3/2 dominate the emissions when excited with shorter wavelengths (≤312 nm). • The lifetime of 2 P 3/2 emissions (460 μs) is longer than that of 4 S 3/2 (248 μs). • The NIR luminescence in the range from 750 to 1650 nm consists of six bands. • NIR quantum cutting processes are observed

  7. Synthesis, structure and photoluminescence of novel lanthanide (Tb(III), Gd(III)) complexes with 6-diphenylamine carbonyl 2-pyridine carboxylate

    International Nuclear Information System (INIS)

    An Baoli; Gong Menglian; Cheah, Kok-Wai; Wong, Wai-Kwok; Zhang Jiming

    2004-01-01

    A novel organic ligand, 6-diphenylamine carbonyl 2-pyridine carboxylic acid (HDPAP), and the corresponding lanthanide complexes, tris(6-diphenylamine carbonyl 2-pyridine carboxylato) terbium(III) (Tb-DPAP) and tris(6-diphenylamine carbonyl 2-pyridine carboxylato) gadolinium(III) (Gd-DPAP) have been designed and synthesized. The crystal structure and photoluminescence of Tb-DPAP and Gd-DPAP have been studied. The results showed that the lanthanide complexes have electroneutral structures, and the solid terbium complex emits characteristic green fluorescence of Tb(III) ions at room temperature while the gadolinium complex emits the DPAP ligand phosphorescence. The lowest triplet level of DPAP ligand was calculated from the phosphorescence spectrum of Gd-DPAP in N,N-dimethyl formamide (DMF) dilute solution determined at 77 K, and the energy transfer mechanisms in the lanthanide complexes were discussed. The lifetimes of the 5 D 4 levels of Tb 3+ ions in the terbium complex were examined using time-resolved spectroscopy, and the values are 0.0153±0.0001 ms for solid Tb(DPAP) 3 ·11.5H 2 O and 0.074±0.007 ms for 2.5x10 -5 mol/l Tb-DPAP ethanol solution

  8. Rare Earth Dopant (Nd, Gd, Dy, and Er Hybridization in Lithium Tetraborate

    Directory of Open Access Journals (Sweden)

    Tony D. Kelly

    2014-05-01

    Full Text Available The four dopants (Nd, Gd, Dy, and Er substitutionally occupy the Li+ sites in lithium tetraborate (Li2B4O7: RE glasses as determined by analysis of the extended X-ray absorption fine structure. The dopants are coordinated by 6-8 oxygen at a distance of 2.3 to 2.5 Å, depending on the rare earth. The inverse relationship between the RE¬ O coordination distance and rare earth (RE atomic number is consistent with the expected lanthanide atomic radial contraction with increased atomic number. Through analysis of the X-ray absorption near edge structure, the rare earth dopants adopt the RE3+ valence state. There are indications of strong rare earth 5d hybridization with the trigonal and tetrahedral formations of BO3 and BO4 based on the determination of the rare earth substitutional Li+ site occupancy from the X-ray absorption near edge structure data. The local oxygen disorder around the RE3+ luminescence centers evident in the structural determination of the various glasses, and the hybridization of the RE3+ dopants with the host may contribute to the asymmetry evident in the luminescence emission spectral lines. The luminescence emission spectra are indeed characteristic of the expected f-to-f transitions; however, there is an observed asymmetry in some emission lines.

  9. Levels in Gd156 excited in the decay of 5.6 d Tb156

    DEFF Research Database (Denmark)

    Hansen, P.Gregers; Nielsen, O.B.; Sheline, R.K.

    1959-01-01

    The decay of 5.6 day Tb156 has been studied by means of a six gap β-ray spectrometer, scintillation spectrometers, and coincidence techniques. Conversion electron and γ-ray coincidence measurements have been used extensively for obtaining quantitative estimates of γ-ray intensities. A description...... of the electronic equipment is given, including a scaler and gate unit, which improves the performance of a relatively slow (τ = 700 μsec) multichannel analyzer. 24 transitions are assigned to Tb156. Multipole orders are given in most cases. The following levels are proposed and their quantum numbers (K, I, π...

  10. Electrical characteristics of hybrid detector based Gd{sub 2}O{sub 2}S:Tb-Selenium for digital radiation imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Sang-Sik [Department of Biomedical Engineering, College of Biomedical Science and Engineering, Inje University, Kimhae, Kyungnam 621-749 (Korea, Republic of); Park, Ji-Koon [Department of Biomedical Engineering, College of Biomedical Science and Engineering, Inje University, Kimhae, Kyungnam 621-749 (Korea, Republic of); Choi, Jang-Yong [Department of Biomedical Engineering, College of Biomedical Science and Engineering, Inje University, Kimhae, Kyungnam 621-749 (Korea, Republic of); Cha, Byung-Yul [Department of Biomedical Engineering, College of Biomedical Science and Engineering, Inje University, Kimhae, Kyungnam 621-749 (Korea, Republic of); Cho, Sung-Ho [Department of Biomedical Engineering, College of Biomedical Science and Engineering, Inje University, Kimhae, Kyungnam 621-749 (Korea, Republic of); Nam, Sang-Hee [Medical Imaging Research Center, Inje University, Kimhae, Kyungnam 621-749 (Korea, Republic of)

    2005-07-01

    Fine Gd{sub 2}O{sub 2}S:Tb powders were synthesized by using a solution-combustion method for a high-resolution digital X-ray imaging detector. The PL spectrum showed that the phosphor was fully crystallized and that the Tb{sup 3+} ions substituted well for the Gd{sup 3+} sites. To investigate the X-ray response of the phosphor, a uniform Gd{sub 2}O{sub 2}S:Tb film was grown using a screen-printing method. The X-ray sensitivities of the 100 {mu}m-Gd{sub 2}O{sub 2}S:Tb/30 {mu}m -Se and 200 {mu}m -Se detector were 470 and 420 pC/cm{sup 2}/mR, respectively, at an electric field of 10 V/{mu}m. The results of the study suggest that the hybrid detector has a significant potential in the application of digital radiography and fluoroscopy systems.

  11. Host sensitization of Tb3+ ions in tribarium lanthanide borates Ba3Ln (BO3)3 (Ln = Lu and Gd).

    Science.gov (United States)

    Wang, De-Yin; Chen, Teng-Ming; Cheng, Bing-Ming

    2012-03-05

    The vacuum-ultraviolet (VUV) spectroscopic properties of undoped and Tb(3+)-doped borates Ba(3)Ln(BO(3))(3) (Ln = Lu and Gd) with different crystal structures were investigated by using synchrotron radiation. Ba(3)Lu(BO(3))(3) (BLB) crystallizes in a hexagonal structure, whereas Ba(3)Gd(BO(3))(3) (BGB) crystallizes in a trigonal structure. The maximum host absorption for BLB and BGB was found to locate at ~179 and ~195 nm, respectively. Upon host excitation, BLB exhibits an intrinsic broad UV emission centered at 339 nm, which is attributed to the recombination of self-trapped excitons that may presumably be associated with band-gap excitations or molecular transitions within the BO(3)(3-) group. In contrast to BLB, no broad emission but line emission ascribed to a Gd(3+)(6)P(J)-(8)S(7/2) transition was observed in the emission spectrum of BGB. Upon doping of Tb(3+) ions into the hosts of BLB and BGB, an efficient energy transfer from the host excitations to Tb(3+) via host/Gd(3+) emission was observed, showing that host sensitization of Tb(3+) occurs in these rare-earth borates.

  12. Study of the influence of the codopant over the photoluminescent properties of PAA doped with Eu3+, Gd3+, and Tb3+

    International Nuclear Information System (INIS)

    Flores, M.; Arroyo, R.

    2003-01-01

    The results are presented obtained about the synthesis of acrylic poly acid characterization (PAA) doped with Eu 3+ , Gd 3+ and Tb 3+ . They got ready materials with even of these ions and it was studied the influence of the co dopant in the processes of emission of Eu 3+ (λ em = 618 nm), Gd 3+ (λ em = 624 nm) and Tb 3+ (λ em = 546 nm), as well as their effect in the phosphorescence (λ em = 450 nm) of the polymeric matrix. It was found that the intensity of the emission of Eu 3+ diminishes substantially due to the presence of the ions Gd 3+ , contrary to what happens when the co dopant is Tb 3+ , which causes an increase. In the one case of the emission of Tb 3+ , this it increases with the presence of Gd 3+ but it diminishes when Eu 3+ is present. These results are consequence of the homogeneous distribution of those dopants and of the phenomena of energy transfer that happen in the materials synthesized. (Author)

  13. Theoretical investigations on magnetocaloric effect in Er{sub 1−y}Tb{sub y}Al{sub 2} series

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, P.O., E-mail: paula.ribeiro@gmail.com [Instituto de Física, Universidade do Estado do Rio de Janeiro – UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil); Alho, B.P.; Alvarenga, T.S.T.; Nóbrega, E.P.; Sousa, V.S.R. de [Instituto de Física, Universidade do Estado do Rio de Janeiro – UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil); Carvalho, A. Magnus G. [Laboratório Nacional de Luz Síncrotron, CNPEM, 13083-970 Campinas, SP (Brazil); Caldas, A. [Sociedade Unificada de Ensino Superior e Cultura, SUESC, 20211-351 Rio de Janeiro, RJ (Brazil); Oliveira, N.A. de; Ranke, P.J. von [Instituto de Física, Universidade do Estado do Rio de Janeiro – UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil)

    2015-04-01

    We report on the magnetic and magnetocaloric effect calculations in rare earth Er{sub 1−y}Tb{sub y}Al{sub 2} compounds (y=0.00, 0.25, 0.5, 0.75 and 1.00). Our model Hamiltonian has contributions of the crystalline electrical field anisotropy in both Er and Tb magnetic sublattices, disorder in exchange interactions among Er–Er, Tb–Tb and Er–Tb magnetic ions and the Zeeman effect. The magnetization, the isothermal entropy change (ΔS{sub T}) and the adiabatic temperature change (ΔT{sub ad}) dependence on temperature were simulated and, compared with the experimental data available. - Highlights: • Modeling Er{sub (1−y)}Tb{sub y}Al{sub 2} intermetallic compounds. • Magnetic entropy changes in Er{sub (1−y)}Tb{sub y}Al{sub 2}. • Adiabatic temperature changes in Er{sub 0.75}Tb{sub 0.25}Al{sub 2} and Er{sub 0.65}Tb{sub 0.35}Al{sub 2} compounds.

  14. RNi{sub 8}Si{sub 3} (R=Gd,Tb): Novel ternary ordered derivatives of the BaCd{sub 11} type

    Energy Technology Data Exchange (ETDEWEB)

    Pani, M., E-mail: marcella@chimica.unige.it [Department of Chemistry, University of Genova, Via Dodecaneso 31, 16146 Genova (Italy); Institute SPIN-CNR, Corso Perrone 24, 16152 Genova (Italy); Morozkin, A.V. [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, Moscow, GSP-2 119992 (Russian Federation); Yapaskurt, V.O. [Department of Petrology, Geological Faculty, Moscow State University, Leninskie Gory, Moscow 119992 (Russian Federation); Provino, A.; Manfrinetti, P. [Department of Chemistry, University of Genova, Via Dodecaneso 31, 16146 Genova (Italy); Institute SPIN-CNR, Corso Perrone 24, 16152 Genova (Italy); Nirmala, R. [Indian Institute of Technology Madras, Chennai 600036 (India); Malik, S.K. [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, Natal 59082-970 (Brazil)

    2016-01-15

    The title compounds have been synthesized and characterized both from the structural and magnetic point of view. Both crystallize in a new monoclinic structure strictly related to the tetragonal BaCd{sub 11} type. The structure was solved by means of X-ray single-crystal techniques for GdNi{sub 8}Si{sub 3} and confirmed for TbNi{sub 8}Si{sub 3} on powder data; the corresponding lattice parameters (obtained from Guinier powder patterns) are a=6.3259(2), b=13.7245(5), c=7.4949(3) Å, β=113.522(3)°, V{sub cell}=596.64(3) Å{sup 3} and a=6.3200(2), b=13.6987(4), c=7.4923(2) Å, β=113.494(2)°, V{sub cell}=594.88(2) Å{sup 3}. The symmetry relationship between the tI48-I4{sub 1}/amd BaCd{sub 11} aristotype and the new ordered mS48-C2/c GdNi{sub 8}Si{sub 3} derivative is described via the Bärnighausen formalism within the group theory. The large Gd–Gd (Tb–Tb) distances, mediated via Ni–Si network, likely lead to weak magnetic interactions. Low-field magnetization vs temperature measurements indicate weak and field-sensitive antiferromagnetic ground state, with ordering temperatures of 3 K in GdNi{sub 8}Si{sub 3} and about 2–3 K in TbNi{sub 8}Si{sub 3}. On the other hand, the isothermal field-dependent magnetization data show the presence of competing interactions in both compounds, with a field-induced ferromagnetic behavior for GdNi{sub 8}Si{sub 3} and a ferrimagnetic-like behavior in TbNi{sub 8}Si{sub 3} at the ordering temperature T{sub C/N} of about (or slightly higher than) 3K. The magnetocaloric effect, quantified in terms of isothermal magnetic entropy change ΔS{sub m}, has the maximum values of –19.8 J(kg K){sup −1} (at 4 K for 140 kOe field change) and −12.1 J(kg K){sup −1} (at 12 K for 140 kOe field change) in GdNi{sub 8}Si{sub 3} and TbNi{sub 8}Si{sub 3}, respectively. - Graphical abstract: GdNi{sub 8}Si{sub 3} and TbNi{sub 8}Si{sub 3} compounds are isostructural, and crystallize in a new monoclinic type strictly related to the tetragonal

  15. Theoretical investigations on magnetic entropy change in amorphous and crystalline systems: Applications to RAg (R=Tb, Dy, Ho) and GdCuAl

    Energy Technology Data Exchange (ETDEWEB)

    Ranke, P.J. von, E-mail: von.ranke@uol.com.br [Instituto de Física, Universidade do Estado do Rio de Janeiro – UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil); Nóbrega, E.P. [Instituto de Física, Universidade do Estado do Rio de Janeiro – UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil); Caldas, A. [Sociedade Unificada de Ensino Superior e Cultura, SUESC, 20211-351 Rio de Janeiro, RJ (Brazil); Alho, B.P. [Instituto de Aplicação Fernando Rodrigues da Silveira, Universidade do Estado do Rio de Janeiro, Rua Santa Alexandrina, 288, 20260-232 RJ (Brazil); Ribeiro, P.O.; Alvarenga, T.S.T.; Lopes, P.H.O.; Sousa, V.S.R. de [Instituto de Física, Universidade do Estado do Rio de Janeiro – UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil); Carvalho, A. Magnus G. [Laboratório Nacional de Luz Síncrotron, CNPEM, 13083-970 Campinas, SP (Brazil); Oliveira, N.A. de [Instituto de Física, Universidade do Estado do Rio de Janeiro – UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil)

    2014-11-15

    We report theoretical investigations on the magnetic entropy changes in amorphous systems through two different assumptions. In the first assumption, the HPZ-anisotropic model is considered to deal with the random direction of magnetic moments, where the amorphous RAg (R=Tb, Dy and Ho) were used as prototypes systems. In the second assumption, the amorphisation is parameterized through the exchange interaction distribution and GdCuAl, in amorphous and crystalline structures, were considered as prototypes systems. Comparisons between the magnetic entropy changes under amorphisation and under the usual magnetic field variation were performed. The model reveals the dependence of refrigerant capacity on the amorphisation parameter, and an optimum amorphisation parameter was calculated. - Highlights: • Theoretical investigation on RAg (R=Tb, Dy and Ho) and GdCuAl amorphous alloys. • Magnetic entropy changes in GdCuAl in both amorphous and crystalline structures. • The refrigerant capacity was compared in both amorphous and crystalline phases.

  16. Rare Earth Chalcogels NaLnSnS4 (Ln = Y, Gd, Tb) for Selective Adsorption of Volatile Hydrocarbons and Gases

    KAUST Repository

    Edhaim, Fatimah

    2017-06-28

    The synthesis and characterization of the rare earth chalcogenide aerogels NaYSnS4, NaGdSnS4, and NaTbSnS4 is reported. Rare earth metal ions like Y3+, Gd3+, and Tb3+ react with the chalcogenide clusters [SnS4]4– in aqueous formamide solution forming extended polymeric networks by gelation. Aerogels obtained after supercritical drying have BET surface areas of 649 m2·g–1 (NaYSnS4), 479 m2·g–1 (NaGdSnS4), and 354 m2·g–1 (NaTbSnS4). Electron microscopy and physisorption studies reveal that the new materials have pores in the macro (above 50 nm) and meso (2–50 nm) regions. These aerogels show higher adsorption of toluene vapor over cyclohexane vapor and CO2 over CH4 or H2. The notable adsorption capacity for toluene (NaYSnS4: 1108 mg·g–1; NaGdSnS4: 921 mg·g–1; and NaTbSnS4: 645 mg·g–1) and high selectivity for gases (CO2/H2: 172 and CO2/CH4: 50 for NaYSnS4, CO2/H2: 155 and CO2/CH4: 37 for NaGdSnS4, and CO2/H2: 75 and CO2/CH4: 28 for NaTbSnS4) indicate potential future use of chalcogels in adsorption-based gas or hydrocarbon separation processes.

  17. Multifunctional hydroxyapatite/Na(Y/Gd)F4:Yb3+,Er3+ composite fibers for drug delivery and dual modal imaging.

    Science.gov (United States)

    Liu, Min; Liu, Hui; Sun, Shufen; Li, Xuejiao; Zhou, Yanmin; Hou, Zhiyao; Lin, Jun

    2014-02-04

    Porous hydroxyapatite (HAp) composite fibers functionalized with up-conversion (UC) luminescent and magnetic Na(Y/Gd)F4:Yb(3+),Er(3+) nanocrystals (NCs) have been fabricated via electrospinning. After transferring hydrophobic oleic acid-capped Na(Y/Gd)F4:Yb(3+),Er(3+) NCs into aqueous solution, these water-dispersible NCs were dispersed into precursor electrospun solution containing CTAB. Na(Y/Gd)F4:Yb(3+),Er(3+)@HAp composite fibers were fabricated by the high temperature treatment of the electrospun Na(Y/Gd)F4:Yb(3+),Er(3+) NCs decorated precursor fibers. The biocompatibility test on MC 3T3-E1 cells using MTT assay shows that the HAp composite fibers have negligible cytotoxity, which reveals the HAp composite fibers could be a drug carrier for drug delivery. Because the contrast brightening is enhanced at increased concentrations of Gd(3+), the HAp composite fibers can serve as T1 magnetic resonance imaging contrast agents. In addition, the composites uptaken by MC 3T3-E1 cells present the UC luminescent emission of Er(3+) under the excitation of a 980 nm near-infrared laser. The above findings reveal Na(Y/Gd)F4:Yb(3+),Er(3+)@HAp composite fibers have potential applications in drug storage/release and magnetic resonance/UC luminescence imaging.

  18. Magnetic properties of CaCu{sub 5}-type RNi{sub 3}TSi (R=Gd and Tb, T=Mn, Fe, Co and Cu) compounds

    Energy Technology Data Exchange (ETDEWEB)

    Morozkin, A.V., E-mail: morozkin@tech.chem.msu.ru [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, GSP-2, Moscow 119992 (Russian Federation); Knotko, A.V. [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, GSP-2, Moscow 119992 (Russian Federation); Yapaskurt, V.O. [Department of Petrology, Geological Faculty, Moscow State University, Leninskie Gory, Moscow 119992 (Russian Federation); Yao, Jinlei [Research Center for Solid State Physics and Materials, School of Mathematics and Physics, Suzhou University of Science and Technology, Suzhou 215009 (China); Yuan, Fang; Mozharivskyj, Y. [Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4M1 (Canada); Nirmala, R. [Indian Institute of Technology Madras, Chennai 600036 (India); Quezado, S.; Malik, S.K. [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, Natal 59082-970 (Brazil)

    2015-12-15

    Magnetic properties and magnetocaloric effect of CaCu{sub 5}-type RNi{sub 3}TSi (R=Gd and Tb, T=Mn, Fe, Co and Cu) compounds have been investigated. Magnetic measurements of RNi{sub 3}TSi display the increasing of Curie temperature and the decreasing of magnetocaloric effect and saturated magnetic moment in the row of ‘RNi{sub 3}CuSi–RNi{sub 3}NiSi–RNi{sub 3}CoSi–RNi{sub 3}MnSi–RNi{sub 3}FeSi’. In contrast to GdNi{sub 3}{Mn, Fe, Co}Si, TbNi{sub 3}{Mn, Fe, Co}Si exhibit significant magnetic hysteresis. The coercive field increases from TbNi{sub 4}Si (~0.5 kOe) to TbNi{sub 3}CoSi (4 kOe), TbNi{sub 3}MnSi (13 kOe) and TbNi{sub 3}FeSi (16 kOe) in field of 50 kOe at 5 K, whereas TbNi{sub 3}CuSi exhibits a negligible coercive field. - Graphical abstract: Magnetic measurements of RNi{sub 3}TSi show the increasing of Curie temperature and the decreasing of magnetocaloric effect and saturated magnetic moment in the row of 'RNi{sub 3}CuSi–RNi{sub 3}NiSi–RNi{sub 3}CoSi–RNi{sub 3}MnSi–RNi{sub 3}FeSi'. In contrast to GdNi{sub 3}{Mn, Fe, Co}Si, TbNi{sub 3}{Mn, Fe, Co}Si exhibit significant magnetic hysteresis. The coercive field increases from TbNi{sub 4}Si (~0.5 kOe) to TbNi{sub 3}CoSi (4 kOe), TbNi{sub 3}MnSi (13 kOe) and TbNi{sub 3}FeSi (16 kOe) in field of 50 kOe at 5 K, whereas TbNi{sub 3}CuSi exhibits a negligible coercive field. - Highlights: • CaCu{sub 5}-type RNi{sub 3}TSi show ferromagnetic ordering (R=Gd, Tb, T=Mn–Co, Cu). • Curie point increases in ‘RNi{sub 3}CuSi–RNi{sub 3}NiSi–RNi{sub 3}CoSi–RNi{sub 3}MnSi–RNi{sub 3}FeSi’ row. • MCE decreases in ‘RNi{sub 3}CuSi–RNi{sub 3}NiSi–RNi{sub 3}CoSi–RNi{sub 3}MnSi–RNi{sub 3}FeSi’ row. • TbNi{sub 3}{Mn, Fe, Co}Si exhibit significant magnetic hysteresis. • The coercive field of TbNi{sub 3}MnSi and TbNi{sub 3}FeSi reach 13 kOe and 16 kOe at 5 K.

  19. Polynuclear coordination precursor compounds for M3Fe5O12 garnets (M = Y, Eu, Gd and Er.

    Directory of Open Access Journals (Sweden)

    LUMINITA PATRON

    2005-09-01

    Full Text Available A new type of complexes compounds (NH46[M3Fe5(C4O5H46(C4O5H36]·16H2O (where M(III = Y, Eu, Gd, Er, (NH46[M3Fe5(C4O6H46(C4O6H36]·16H2O (where M(III = Gd, Er and (NH46[M3Fe5(C6O7H106(C6O7H96]·xH2O (where M(III = Y; x = 8; M(III = Eu, Er; x = 22 [C4O5H42– = malate anion; C4O6H42– = tartarate anion, C6O7H11– = gluconate anion] have been synthesized and characterised by elemental chemical analysis and physico-chemical measurements (IR, UV-Vis spectroscopy and magnetic determinations. The synthetic possibilities offered by the use of these new compounds as potential precursors for garnets have been suggested.

  20. Effect of rapid quenching on the magnetism and magnetocaloric effect of equiatomic rare earth intermetallic compounds RNi (R = Gd, Tb and Ho)

    Energy Technology Data Exchange (ETDEWEB)

    Rajivgandhi, R. [Department of Physics, Indian Institute of Technology Madras, Chennai 600 036 (India); Arout Chelvane, J. [Defence Metallurgical Research Laboratory, Hyderabad 500 058 (India); Quezado, S.; Malik, S.K. [Departamento de F’ısica Teorica e Experimental, Universidade Federal do Rio Grande do Norte, Natal 59072-970 (Brazil); Nirmala, R., E-mail: nirmala@physics.iitm.ac.in [Department of Physics, Indian Institute of Technology Madras, Chennai 600 036 (India)

    2017-07-01

    Highlights: • Melt-spinning yields microcrystalline RNi (R = Gd, Tb and Ho) samples with texture. • The texture-induced anisotropy affects magnetic and magnetocaloric properties. • Melt-spinning helps one engineer magnetocaloric effect in rare-earth compounds. - Abstract: Magnetocaloric effect (MCE) in RNi (where R = Gd, Tb and Ho) compounds has been studied in their arc-melted and melt-spun forms. The compound GdNi has the orthorhombic CrB-type structure (Space group Cmcm, No. 63) and the compound HoNi has the orthorhombic FeB-type structure (Space group Pnma, No. 62) at room temperature regardless of their synthesis condition. However, arc-melted TbNi orders in a monoclinic structure (Space group P2{sub 1}/m, No. 11) and when it is rapidly quenched to a melt-spun form, it crystallizes in an orthorhombic structure (Space group Pnma, No. 62). The arc-melted GdNi, TbNi and HoNi compounds order ferromagnetically at ∼69 K, ∼67 K and ∼36 K (T{sub C}) respectively. While the melt-spun GdNi shows about 6 K increase in T{sub C}, the ordering temperature of TbNi remains nearly the same in both arc-melted and melt-spun forms. In contrast, a reduction in T{sub C} by about 8 K is observed in melt-spun HoNi, when compared to its arc-melted counterpart. Isothermal magnetic entropy change, ∆S{sub m}, calculated from the field dependent magnetization data indicates an enhanced relative cooling power (RCP) for melt-spun GdNi for field changes of 20 kOe and 50 kOe. A lowered RCP value is observed in melt-spun TbNi and HoNi. These changes could have resulted from the competing shape anisotropy and the granular microstructure induced by the melt-spinning process. Tailoring the MCE of rare earth intermetallic compounds by suitably controlled synthesis techniques is certainly one of the directions to go forward in the search of giant magnetocaloric materials.

  1. Syntheses, structure determination, magnetic and thermoelectric properties of quasicrystal approximants in RE-Au-SM systems (RE = Gd, Tb and Yb and SM = Si, Ge)

    OpenAIRE

    Gebresenbut, Girma Hailu

    2014-01-01

    In this study, new compositions of Tsai-type 1/1 quasicrystal approximants Gd(14)Au(70)Si(16), Gd(14)Au(67)Ge(19), Tb(14)Au(70)Si(16) and Yb(16)Au(65)Ge(19)are synthesized using both self-flux and arc-melting-annealing techniques. Both syntheses routes resulted single phase samples. The crystal structures of the compounds are determined by collecting single crystal X-ray and/or powder X-ray and powder neutron diffraction intensities.  The atomic structure refinements indicated that the compou...

  2. Evaluating x-ray detectors for radiographic applications: A comparison of nSCdS:Ag with Gd sub 2 O sub 2 S:Tb and Y sub 2 O sub 2 S:Tb screens

    CERN Document Server

    Kandarakis, I; Panayiotakis, G S; Nomicos, C D

    1997-01-01

    ZnSCdS:Ag was evaluated as a radiographic image receptor and was compared with Gd sub 2 O sub 2 S:Tb and Y sub 2 O sub 2 S:Tb phosphors often used in radiography. The valuation of a radiographic receptor was modelled as a three-step process: i) determination of light output intensity as related to the input radiation dose, (ii) determination of visible light characteristics with respect to radiographic optical detectors, and (iii) determination of image information transfer efficiency. The light intensity emitted per unit of x-ray exposure rate was measured and theoretically calculated for laboratory prepared screens with coating thicknesses from 20 to 220 mg cm sup - sup 2 and tube voltages rom 50 to 250 kVp. ZnSCdS:Ag light intensity was higher than that of d sub 2 O sub 2 S:Tb or Y sub 2 O sub 2 S:Tb for tube voltages less than 70 and 80 kVp respectively. ZnSCdS:Ag displayed the highest x-ray to light conversion efficiency (0.207) and had optical properties close to those of Gd sub 2 O sub 2 S:Tb nd Y sub ...

  3. Synthesis and functionalization of NaGdF4:Yb,Er@NaGdF4 core–shell nanoparticles for possible application as multimodal contrast agents

    Directory of Open Access Journals (Sweden)

    Dovile Baziulyte-Paulaviciene

    2017-09-01

    Full Text Available Upconverting nanoparticles (UCNPs are promising, new imaging probes capable of serving as multimodal contrast agents. In this study, monodisperse and ultrasmall core and core–shell UCNPs were synthesized via a thermal decomposition method. Furthermore, it was shown that the epitaxial growth of a NaGdF4 optical inert layer covering the NaGdF4:Yb,Er core effectively minimizes surface quenching due to the spatial isolation of the core from the surroundings. The mean diameter of the synthesized core and core–shell nanoparticles was ≈8 and ≈16 nm, respectively. Hydrophobic UCNPs were converted into hydrophilic ones using a nonionic surfactant Tween 80. The successful coating of the UCNPs by Tween 80 has been confirmed by Fourier transform infrared (FTIR spectroscopy. Scanning electron microscopy (SEM, powder X-ray diffraction (XRD, photoluminescence (PL spectra and magnetic resonance (MR T1 relaxation measurements were used to characterize the size, crystal structure, optical and magnetic properties of the core and core–shell nanoparticles. Moreover, Tween 80-coated core–shell nanoparticles presented enhanced optical and MR signal intensity, good colloidal stability, low cytotoxicity and nonspecific internalization into two different breast cancer cell lines, which indicates that these nanoparticles could be applied as an efficient, dual-modal contrast probe for in vivo bioimaging.

  4. Study of X-ray L2 absorption edges of Gd, Dy, Ho and Er in metals and compounds

    International Nuclear Information System (INIS)

    Agarwal, B.K.; Agarwal, B.R.K.

    1978-01-01

    The positions and shapes of L2 X-ray absorption edges of Gd, Dy, Ho and Er have been studied in metals and in oxides and chlorides, using a forty centimetre bent mica crystal spectrograph. It has been found that the L2 edge shifts towards the high energy side in the compounds and that the chemical shift ΔE depends on the degree of covalency involved. The white line structure at the edge has been analysed in terms of transitions of L2 shell electron to optical nd (n >= 5) states. (author)

  5. Predictions of thermomagnetic properties of Laves phase compounds: TbAl2, GdAl2 and SmAl2 performed with ATOMIC MATTERS MFA computation system

    Science.gov (United States)

    Michalski, Rafał; Zygadło, Jakub

    2018-04-01

    Recent calculations of properties of TbAl2 GdAl2 and SmAl2 single crystals, performed with our new computation system called ATOMIC MATTERS MFA are presented. We applied localized electron approach to describe the thermal evolution of Fine Electronic Structure of Tb3+, Gd3+ and Sm3+ ions over a wide temperature range and estimate Magnetocaloric Effect (MCE). Thermomagnetic properties of TbAl2, GdAl2 and SmAl2 were calculated based on the fine electronic structure of the 4f8, 4f7 and 4f5 electronic configuration of the Tb3+ and Gd3+ and Sm3+ ions, respectively. Our calculations yielded: magnetic moment value and direction; single-crystalline magnetization curves in zero field and in external magnetic field applied in various directions m(T,Bext); the 4f-electronic components of specific heat c4f(T,Bext); and temperature dependence of the magnetic entropy and isothermal entropy change with external magnetic field - ΔS(T,Bext). The cubic universal CEF parameters values used for all CEF calculations was taken from literature and recalculated for universal cubic parameters set for the RAl2 series: A4 = +7.164 Ka04 and A6 = -1.038 Ka06. Magnetic properties were found to be anisotropic due to cubic Laves phase C15 crystal structure symmetry. These studies reveal the importance of multipolar charge interactions when describing thermomagnetic properties of real 4f electronic systems and the effectiveness of an applied self-consistent molecular field in calculations for magnetic phase transition simulation.

  6. Study of the influence of the codopant over the photoluminescent properties of PAA doped with Eu{sup 3+}, Gd{sup 3+}, and Tb{sup 3+}; Estudio de la influencia del codopante sobre las propiedades fotoluminiscentes de PAA dopado con Eu{sup 3+}, Gd{sup 3+} y Tb{sup 3+}

    Energy Technology Data Exchange (ETDEWEB)

    Flores, M.; Arroyo, R. [Departamento de Fisica, UAM-I, A.P. 55-534, 09820 Mexico D.F. (Mexico)

    2003-07-01

    The results are presented obtained about the synthesis of acrylic poly acid characterization (PAA) doped with Eu{sup 3+}, Gd{sup 3+} and Tb{sup 3+}. They got ready materials with even of these ions and it was studied the influence of the co dopant in the processes of emission of Eu{sup 3+} ({lambda}{sub em} = 618 nm), Gd{sup 3+} ({lambda}{sub em} = 624 nm) and Tb{sup 3+} ({lambda}{sub em} = 546 nm), as well as their effect in the phosphorescence ({lambda}{sub em} = 450 nm) of the polymeric matrix. It was found that the intensity of the emission of Eu{sup 3+} diminishes substantially due to the presence of the ions Gd{sup 3+}, contrary to what happens when the co dopant is Tb{sup 3+} , which causes an increase. In the one case of the emission of Tb{sup 3+}, this it increases with the presence of Gd{sup 3+} but it diminishes when Eu{sup 3+} is present. These results are consequence of the homogeneous distribution of those dopants and of the phenomena of energy transfer that happen in the materials synthesized. (Author)

  7. The effect of pressure on the magnetic susceptibility of RInCu4 (R = Gd, Er and Yb)

    Science.gov (United States)

    Svechkarev, I. V.; Panfilov, A. S.; Dolja, S. N.; Nakamura, H.; Shiga, M.

    1999-06-01

    The magnetic susceptibility of the intermetallic compounds RInCu4 (R = Gd, Er and Yb) was measured under helium gas pressure up to 2 kbar at the fixed temperatures 78, 150 and 300 K. For YbInCu4, which exhibits a first-order valence phase transition at TVicons/Journals/Common/simeq" ALT="simeq" ALIGN="TOP"/>40 K, the Grüneisen parameter for the Kondo energy, icons/Journals/Common/Omega" ALT="Omega" ALIGN="TOP"/>Kicons/Journals/Common/equiv" ALT="equiv" ALIGN="TOP"/>-dlnTK/dlnV = -32, is large and typical for Ce-based heavy-fermion systems in magnitude but opposite in sign. The effect of atomic disorder is discussed on the basis of the data for a chemically disordered sample; the pressure effect at T = 78 K is strongly enhanced due to the spatial dispersion of pressure-sensitive TV, and hence dTV/dP = -2.0 K kbar-1 is obtained by assuming a Gaussian distribution of TV. On the basis of an extrapolation of the experimental pressure dependence, a (P,T) phase diagram is proposed for YbInCu4. Reference compounds with stable f moments, GdInCu4 and ErInCu4, show negligible pressure dependences of the susceptibility.

  8. Spectral management and morphology evolution of β-NaGdF4:Yb3+,Er3+ by tuning the concentration of citric acid

    Science.gov (United States)

    Yao, Lu; Xu, Dekang; Lin, Hao; Yang, Shenghong; Zhang, Yueli

    2018-05-01

    β-NaGdF4:Yb3+,Er3+ upconversion (UC) particles were prepared by a facile hydrothermal process with assistance of citric acid (CA). The morphologies of β-NaGdF4 UC particles were controlled by changing the doses of CA in precursor. With an increase CA concentration in precursor, increase sizes of crystals were observed, resulting in the increasing of luminescence intensity. The energy transfer ET mechanism was analyzed in detail.

  9. Investigation of local magnetism in RZn (R = Ce, Gd, Tb, Dy) and GdCu intermetallic compounds using perturbed angular correlation gamma-gamma spectroscopy; Investigacao do magnetismo local em compostos intermetalicos do tipo RZn (R = Ce, Gd, Tb, Dy) e GdCu pela espectroscopia de correlacao angular gama-gama perturbada

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Brianna Bosch dos

    2010-07-01

    This work presents, from a microscopic point of view, a systematic study of the local magnetism in RZn (R = Ce, Gd, Tb, Dy) and GdCu intermetallic compounds through measurements of hyperfine interactions using the Perturbed Angular Correlation Gamma- Gamma Spectroscopy technique with {sup 111}In {yields} {sup 111}Cd and {sup 140}La {yields} {sup 140}Ce as probe nuclei. As the magnetism in these compounds originates from the 4f electrons of the rare-earth elements it is interesting to observe in a systematic study of RZn compounds the behavior of the magnetic hyperfine field with the variation of the number of 4f electrons in the R element. The use of probe nuclei {sup 140}La {yields} {sup 140}Ce is interesting because Ce{sup +3} ion posses one 4f electron which may contribute to the total hyperfine field, and the results showed anomalous behavior. The results for {sup 111}Cd probe showed that the temperature dependence of the magnetic hyperfine field follows the Brillouin function, and the magnetic hyperfine field decreases linearly with increase of the atomic number of rare earth when plotted as a function of the rare-earth J spin projection, showing that the main contribution to the magnetic hyperfine field in RZn compounds comes from the polarization of the conduction electrons. The results for the electric field gradient measured with {sup 111}Cd for all compounds showed a strong decrease with the atomic number of the rare-earth element. We have therefore assumed that the major contribution to the electric field gradient originates from the 4f electrons of the rare-earths. The measurements of the electric field gradient for GdCu with {sup 111}Cd, after temperature decreases and increases again showed that two different structures, CsCl-type cubic and FeB-type orthorhombic structures co-exist. Finally, it is the first time that measurements of hyperfine parameters have been carried out with theses two probe nuclei in the studied RZn. (author)

  10. Optical temperature sensing of Er3+/Yb3+ doped LaGdO3 based on fluorescence intensity ratio and lifetime thermometry

    Science.gov (United States)

    Siaï, A.; Haro-González, P.; Horchani Naifer, K.; Férid, M.

    2018-02-01

    The investigation of the fluorescence intensity ratio and the lifetime thermometry techniques for two rare earth perovskites-type oxide (LaGdO3:Er3+ and LaGdO3:Er3+/Yb3+) has been carried out. We have demonstrated that the intensity ratio of thermally coupled levels of erbium (2H11/2 and 4S3/2) is temperature dependant in the range from 283 to 393 K. The sensitivity parameter was found to reach a maximum value of 31 × 10-4 K-1 and 34 × 10-4 K-1 at 393 K and the temperature resolution to be equivalent to 1.61 and 3.1 K, for Er3+ and Er3+/Yb3+ doped oxide, respectively. By studying the temperature dependence of the normalized lifetimes in the range from 293 to 348 K, we proved that the sensitivity of the green emission (4S3/2) is higher than the red one (4F9/2) for both samples, and that it increases from 144 × 10-4 K-1 for LaGdO3:Er3+ to 179 × 10-4 K-1 for LaGdO3:Er3+/Yb3+. The thermal coefficients were quite large in comparison to those calculated for different luminescent materials and reported in literature. The repeatability of measurements was tested by performing heating and cooling cycles for both methods and the results show that these optical techniques have a good repeatability performance. Hence, the LaGdO3: Er3+, Yb3+ oxide has a precise and a satisfying sensitivity associated to a good thermal and chemical stability, suggesting that it can be a potential candidate in temperature sensing.

  11. Anisotropy in the paramagnetic phase of RAl/sub 2/ cubic intermetallic compounds (R = Tb, Dy, and Er)

    Energy Technology Data Exchange (ETDEWEB)

    del Moral, A.; Ibarra, M.R.; Abell, J.S.; Montenegro, J.F.D.

    1987-05-01

    In this paper it is shown that the anisotropy in the paramagnetic phase is a useful characteristic when used to single out high-rank susceptibility tensor components in the paramagnetic regime of cubic crystals. Application of this technique to RAl/sub 2/ compounds (R = Tb,Dy,Er) allows the determination of longitudinal and transverse (in the form of linear combinations) fourth- and sixth-rank paramagnetic susceptibilities. The use of the fourth-rank longitudinal susceptibility allows quadrupolar pair interactions in these compounds to be probed.

  12. Facile synthesis of intense green light emitting LiGdF4:Yb,Er-based upconversion bipyramidal nanocrystals and their polymer composites.

    Science.gov (United States)

    Na, Hyejin; Jeong, Jong Seok; Chang, Hye Jung; Kim, Hyun You; Woo, Kyoungja; Lim, Kipil; Mkhoyan, K Andre; Jang, Ho Seong

    2014-07-07

    A pathway for achieving intense green light emitting LiGdF4:Yb,Er upconversion nanophosphors (UCNPs) via Y(3+) doping is demonstrated. It was revealed that Y(3+) doping initiated the formation of a tetragonal phase and affected the particle size. Single tetragonal-phase LiGd0.4Y0.4F4:Yb(18%),Er(2%) (LGY0.4F:Yb,Er) UCNPs exhibited strong upconversion (UC) green luminescence and tetragonal bipyramidal morphologies. They showed 1325 and 325-fold higher photoluminescence intensity than the 0 and 80 mol% Y(3+)-doped LiGdF4:Yb,Er UCNPs, respectively. Additionally the particle size (edge length) of LiGdF4:Yb,Er-based upconversion tetragonal bipyramids (UCTBs) was controlled from 60.5 nm to an ultrasmall size of 9.3 nm with varying Y(3+) doping concentration. In an LGY0.4F:Yb,Er UCTB, uniform distribution of all constituent elements was directly confirmed by using high-angle annular dark-field scanning transmission electron microscopy and energy-filtered transmission electron microscopy (EFTEM) image analyses. In particular, existence of activator Er(3+) ions with extremely small quantity was clearly seen over a particle on the EFTEM image. Moreover, the LGY0.4F:Yb,Er UCTBs were successfully incorporated into the polydimethylsiloxane (PDMS) polymer and the highly transparent UCTB-PDMS composites showed bright green light under the excitation of 980 nm infrared light.

  13. Multifunctional MWCNTs-NaGdF4:Yb(3+),Er(3+),Eu(3+) hybrid nanocomposites with potential dual-mode luminescence, magnetism and photothermal properties.

    Science.gov (United States)

    Liu, Wenjia; Liu, Guixia; Dong, Xiangting; Wang, Jinxian; Yu, Wensheng

    2015-09-21

    A novel dual-mode luminescence multifunctional hybrid nanomaterial has been successfully prepared by coating the NaGdF4:Yb(3+),Er(3+),Eu(3+) nanoparticles (NPs) on the surface of MWCNTs. The as-synthesized MWCNTs-NaGdF4:Yb(3+),Er(3+),Eu(3+) nanocomposites (NCs) can simultaneously take advantage of both magnetic and optical properties of NaGdF4:Yb(3+),Er(3+),Eu(3+) NPs and the photothermal conversion property of MWCNTs. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDS), vibrating sample magnetometry (VSM), UV-Vis absorption, luminescence spectroscopy and fluorescence lifetime measurements. Meanwhile, the photothermal conversion was examined under irradiation with a 980 nm laser. The results show that the MWCNTs-NaGdF4:Yb(3+),Er(3+),Eu(3+) NCs have preferably magnetic, dual-mode (up- and down-conversion) luminescence and photothermal properties. And the NCs have good biocompatibility, low toxicity and up-conversion luminescence for cell imaging. As a consequence, the dual-mode luminescence multifunctional nanomaterials have potential applications in environmental science fields and clinical fields for magnetic resonance imaging, fluorescence imaging, photothermal therapy, bioseparation and targeted drug delivery.

  14. The risk assessment of Gd2O3:Yb3+/Er3+ nanocomposites as dual-modal nanoprobes for magnetic and fluorescence imaging

    Science.gov (United States)

    Huang, Long; Tian, Xiumei; Liu, Jun; Zheng, Cunjing; Xie, Fukang; Li, Li

    2017-02-01

    Our group has synthesized Gd2O3:Yb3+/Er3+ nanocomposites as magnetic/fluorescence imaging successfully in the previous study, which exhibit good uniformity and monodispersibility with a mean size of 7.4 nm. However, their systematic risk assessment remains unknown. In this article, the in vitro biocompatibility of the Gd2O3:Yb3+/Er3+ was assessed on the basis of cell viability and apoptosis. In vivo immunotoxicity was evaluated by monitoring the product of reactive oxygen species (ROS), clusters of differentiation (CD) markers, and superoxide dismutase (SOD) in Balb/c mice. No significant differences were found in cell viability, apoptosis, and immunotoxicity between our Gd2O3:Yb3+/Er3+ and gadodiamide which are used commonly in clinical. Few nanoprobes were localized in the phagosomes of the liver, heart, lung, spleen, kidney, brain, and tumor under the transmission electron microscopy (TEM) images. In addition, our products reveal good T1-weighted contrast enhancement of xenografted murine tumor. Therefore, the above results may contribute to the effective application of Gd2O3:Yb3+/Er3+ as molecular imaging contrast agents and dual-modal nanoprobes for cancer detection.

  15. The risk assessment of Gd2O3:Yb3+/Er3+ nanocomposites as dual-modal nanoprobes for magnetic and fluorescence imaging

    International Nuclear Information System (INIS)

    Huang, Long; Tian, Xiumei; Liu, Jun; Zheng, Cunjing; Xie, Fukang; Li, Li

    2017-01-01

    Our group has synthesized Gd 2 O 3 :Yb 3+ /Er 3+ nanocomposites as magnetic/fluorescence imaging successfully in the previous study, which exhibit good uniformity and monodispersibility with a mean size of 7.4 nm. However, their systematic risk assessment remains unknown. In this article, the in vitro biocompatibility of the Gd 2 O 3 :Yb 3+ /Er 3+ was assessed on the basis of cell viability and apoptosis. In vivo immunotoxicity was evaluated by monitoring the product of reactive oxygen species (ROS), clusters of differentiation (CD) markers, and superoxide dismutase (SOD) in Balb/c mice. No significant differences were found in cell viability, apoptosis, and immunotoxicity between our Gd 2 O 3 :Yb 3+ /Er 3+ and gadodiamide which are used commonly in clinical. Few nanoprobes were localized in the phagosomes of the liver, heart, lung, spleen, kidney, brain, and tumor under the transmission electron microscopy (TEM) images. In addition, our products reveal good T 1 -weighted contrast enhancement of xenografted murine tumor. Therefore, the above results may contribute to the effective application of Gd 2 O 3 :Yb 3+ /Er 3+ as molecular imaging contrast agents and dual-modal nanoprobes for cancer detection.

  16. Neutron spectroscopy studies of the crystal-field interaction in RET{sub 4}Al{sub 8} compounds (RE=Tb, Ho or Er; T=Mn, Fe or Cu)

    Energy Technology Data Exchange (ETDEWEB)

    Caciuffo, R.; Amoretti, G.; Buschow, K.H.J.; Moze, O.; Murani, A.P.; Paci, B. [Dipartimento di Sci. dei Mater. e della Terra, Ancona Univ. (Italy)

    1995-10-09

    Inelastic neutron scattering experiments have been performed on some members of the tetragonal RET{sub 4}Al{sub 8} series of compounds (RE=Tb, Ho or Er; T=Mn, Fe or Cu) in order to determine the crystal-field potential at the RE site. A consistent set of the crystal-field parameters has been obtained from the experimental data by a least-squares fit procedure, using information on the second-order term deduced from Moessbauer spectroscopy measurements in {sup 155}GdT{sub 4}Al{sub 8}. The results obtained have been used to estimate the rare-earth contribution to the magnetic anisotropy constants and to discuss the characteristics of possible spin reorientation processes. (authors)

  17. Tune color of single-phase LiGd(MoO4)2-X(WO4)X: Sm3+, Tb3+ via adjusting the proportion of matrix and energy transfer to create white-light phosphor

    Science.gov (United States)

    Wu, Hongyue; Yang, Junfeng; Wang, Xiaoxue; Gan, Shucai; Li, Linlin

    2018-03-01

    A series of LiGd(MO4)2: Sm3+, Tb3+ (M = Mo, W) phosphors was prepared by a conventional solid state reaction method. Powder X-Ray diffraction (XRD) analysis reveals that the compounds are of the same structure type. Their luminescent properties have been studied. The optimal doping concentrations are 8% for Sm3+ and 18% for Tb3+ in the LiGd(MoO4)2 host. Sm3+ and Tb3+ have different sensitivity to the Mo/W ratio. For LiGd(MoO4)2-X(WO4)X: Sm3+ (X = 0, 0.4, 0.8, 1.2, 1.6, 2.0), the strongest emission intensity is 1.766 times than that of the weakest, while 171 times for LiGd(MoO4)2-X(WO4)X: Tb3+. The experimental results show that Mo/W ratio strong influences on the properties of LiGd(MoO4)2-X(WO4)X: Tb3+. With the increasing of WO42- groups concentration, the shape of characteristic excitation peaks of Tb3+ is almost the same and the excitation intensity gradually increase. Moreover, the energy transfer from Tb3+ to Sm3+ has been realized in the co-doped phosphors. The experimental analysis and theoretical calculations reveal that the quadrupole-quadrupole interaction is the dominant mechanism for the Tb3+→Sm3+ energy transfer. Therefore, luminous intensity can be adjusted by different sensitivities to matrix composition and energy transfer from Tb3+→Sm3+. By this tuning color method, white-light-emitting phosphor has been prepared. The excitation wavelength is 378 nm, and this indicates that the white-light-emitting phosphor could be pumped by near-UV light.

  18. Transport properties in amorphous U/sub x/-T1/sub -//sub x/ films (T = Fe, Ni, Gd, Tb, and Yb) (invited)

    International Nuclear Information System (INIS)

    Freitas, P.P.; Plaskett, T.S.; Moreira, J.M.; Amaral, V.S.

    1988-01-01

    We describe the competing magnetic, localization, and phonon effects on the transport properties of amorphous magnetic U/sub x/T/sub 1-//sub x/ films, with T = Fe, Ni, Gd, Tb, and Yb. Amorphous U/sub x/Fe/sub 1-//sub x/ films change from collinear to random ferromagnetism as x increases, and the temperature dependence of the resistivity denotes the competing effects of spin-flip and non-spin-flip exchange scattering processes. The resistivity has a minimum at T/sub f/ rising sharply below this temperature. The sign of the magnetic resistivity and the magnetoresistance indicates >0, while the anisotropic magnetoresistance indicates a local exchange gap. Amorphous U/sub x/Gd/sub 1-//sub x/ and a-U/sub x/Tb/sub 1-//sub x/ are, respectively, spin glasses and random anisotropy dominated systems. The resistivity increases smoothly through T/sub f/ and has a slight upturn at low temperatures that we associate with weak localization. The magnetoresistance is negative in both systems and the anisotropic magnetoresistance is null, although the applied field induces anisotropic behavior in the Tb containing films (asperomagnets). All samples show quadratic and positive field dependence of magnetoresistance well inside the paramagnetic regime, and a linear regime below T/sub f/. At low temperatures and in the a-U/sub x/Gd/sub 1-//sub x/ films, negative (H)/sup 1/2/ and H 2 regimes occur and are associated with weak localization processes dominated by the inelastic mean free path

  19. Quasicrystal Approximants in the RE-Au-SM systems (RE = Gd, Tb, Ho, Yb; SM = Si, Ge) : Syntheses, structures and properties

    OpenAIRE

    Gebresenbut, Girma Hailu

    2016-01-01

    In this study, new Tsai-type 1/1 quasicrystal approximants (ACs) in the RE-Au-SM systems (RE = Gd, Tb, Ho, Yb; SM = Si, Ge) were synthesized using high temperature synthesis techniques such as self-flux, arc-melting-annealing and novel arc-melting-self-flux methods. The syntheses not only provided appropriate samples for the intended structural and physical property measurements but could also be adapted to other systems, especially where crystal growth is a challenge. The newly developed arc...

  20. Production, characterization and application of Gd2O3 and Er2O3 nanoparticles as radiosensitizers in radiotherapy beams

    International Nuclear Information System (INIS)

    Corrêa, Eduardo de Lima

    2017-01-01

    In this study Gd 2 O 3 and Er 2 O 3 nanoparticles were produced for application as radiosensitizers in radiotherapy beams. They were synthesized at the Hyperfine Interactions Laboratory, IPEN, using thermal decomposition method and characterized by X-ray diffraction, to verify crystalline structure, transmission electron microscopy, to obtain information about shape, size and size distribution, neutron activation analysis, whereby it was possible to determine samples purity and gadolinium and erbium concentration. Magnetization and perturbed γ-γ angular correlation (PAC) measurements were performed in order to study particles magnetic behavior and quadrupole interactions, respectively. Characterization results showed a bixbyite structure, 5 nm diameter post-synthesis particles with narrow size distribution. Rare-earth mass determination in each sample was important to perform normalization in magnetic susceptibility measurements, making possible the view of a high magnetization under 30 K for post-synthesis samples, what was not observed in larger particles, together with an effective magnetic moment enhancement for nanoparticles, not seen in bulk samples, and a change in the antiferromagnetic ordering temperature for Er 2 O 3 . PAC spectroscopy results show possible surface effects. The absence of a well-defined frequency in 5 nm samples indicates the amount of 111 In( 111 Cd) at particle surface is bigger than in the core, resulting in a non-evident hyperfine interaction between the probe nuclei and the host. The X-ray diffraction and PAC spectroscopy joint was vital to understand the particles structural damage caused by 60 Co irradiation. About radiosensitizer measurements a dose enhancement factor (DEF) of up to 1,67 and 1,09 for Gd 2 O 3 nanoparticles under 60 Co and 6MV irradiation, respectively, were observed. Under same conditions DEF values of up to 1,37 and 1,06 were found for Er 2 O 3 samples. Results reached in this study provide not only important

  1. Lanthanide stannate pyrochlores (Ln2Sn2O7; Ln  =  Nd, Gd, Er) at high pressure

    Science.gov (United States)

    Turner, Katlyn M.; Tracy, Cameron L.; Mao, Wendy L.; Ewing, Rodney C.

    2017-12-01

    Lanthanide stannate pyrochlores (Ln2Sn2O7; Ln  =  Nd, Gd, and Er) were investigated in situ to 50 GPa in order to determine their structural response to compression and compare their response to that of lanthanide titanate, zirconate, and hafnate pyrochlores. The cation radius ratio of A3+/B4+ in pyrochlore oxides (A2B2O7) is thought to be the dominant feature that influences their response on compression. The ionic radius of Sn4+ is intermediate to that of Ti4+, Zr4+, and Hf4+, but the 〈Sn-O〉 bond in stannate pyrochlore is more covalent than the 〈B-O〉 bonds in titanates, zirconate, and hafnates. In stannates, based on in situ Raman spectroscopy, pyrochlore cation and anion sublattices begin to disorder with the onset of compression, first measured at 0.3 GPa. The extent of sublattice disorder versus pressure is greater in stannates with a smaller Ln3+ cation. Stannate pyrochlores (Fd-3m) begin a sluggish transformation to an orthorhombic, cotunnite-like structure at ~28 GPa similar transitions have been observed in titanate, zirconate, and hafnate pyrochlores at varying pressures (18-40 GPa) with cation radius ratio. The extent of the phase transition versus pressure varies directly with the size of the Ln3+ cation. Post-decompression from ~50 GPa, Er2Sn2O7 and Gd2Sn2O7 adopt a pyrochlore structure, rather than the multi-scale defect-fluorite  +  weberite-type structure adopted by Nd2Sn2O7 that is characteristic of titanate, zirconate, and hafnate pyrochlores under similar conditions. Like pyrochlore titanates, zirconates, and hafnates, the bulk modulus, B 0, of stannates varies linearly and inversely with cation radius ratio from 1 1 1 GPa (Nd2Sn2O7) to 251 GPa (Er2Sn2O7). The trends of bulk moduli in stannates in this study are in excellent agreement with previous experimental studies on stannates and suggest that the size of the Ln3+ cation is the primary determining factor of B 0. Additionally, when normalized to r A

  2. Synthesis and Luminescence Properties of Water Soluble α-NaGdF4/β-NaYF4:Yb,Er Core-Shell Nanoparticles

    Science.gov (United States)

    Chen, Huan; Zhang, Peipei; Cui, Haining; Qin, Weiping; Zhao, Dan

    2017-09-01

    Hexagonal phase (β) sodium rare earth tetrafluorides (NaREF4, RE = Y, Gd, Lu, et al.) are considered the ideal matrices for lanthanide (Ln) ions doped upconversion (UC) luminescence materials, because they can provide favorable crystal lattice structures for the doped luminescent Ln ions to make intensive emissions. However, the cubic phase (α) NaREF4 always preferentially forms at low reaction temperature in short time as it is dynamically stable. Therefore, it is hard to obtain small sized β-NaREF4 via the traditional solvothermal method. In this paper, small sized β-NaYF4:Yb,Er nanoparticles were synthesized by a heterogeneous-core-induced method via the solvothermal reaction. The heterogeneous α-NaGdF4/β-NaYF4: Yb, Er core-shell structure was confirmed by the local elemental mapping. The formation mechanism of β-NaYF4:Yb,Er shell on the surface of α-NaGdF4 core was explained in detail. We reasoned that a hetero interface with a lower lattice symmetric structure was produced by cation exchanges between the core and shell, which caused the preferential growth of anisotropic hexagonal phase shell. The existence of this hetero interface has also been proven by observation of Gd3+ UC emission.

  3. Study of a new magnetic dipole mode in the heavy deformed nuclei 154Sm, 156Gd, 158Gd, 164Dy, 168Er, and 174Yb by high-resolution electron spectroscopy

    International Nuclear Information System (INIS)

    Bohle, D.

    1985-01-01

    By inelastic electron scattering with high energy resolution a new magnetic dipole mode in heavy, deformed nuclei could be detected. For this the nuclei 154 Sm, 156 Gd, 158 Gd, 164 Dy, 168 Er, and 174 Yb were studied at the Darmstadt electron linear accelerator (DALINAC) at small momentum transfer q ≤ 0.6 fm -1 and low excitation energies. A collective magnetic dipole excitation could be discovered in all nuclei at an excitation energy of E x ≅ 66 δA -1/3 MeV whereby δ means the mass deformation. The transition strength extends in the mean to B(M1)↑ ≅ 1.3 μ N 2 . A systematic study of the nucleus 156 Gd yielded hints to a strong fragmentation of the magnetic dipole strength. A comparison of electron scattering, proton scattering, and nuclear resonance fluorescence experiments shows that the new mode is a pure orbital mode. (orig./HSI) [de

  4. Magnetism and Raman spectroscopy of the dimeric lanthanide iodates Ln(IO3)3 (Ln=Gd, Er) and magnetism of Yb(IO3)3

    International Nuclear Information System (INIS)

    Sykora, Richard E.; Khalifah, Peter; Assefa, Zerihun; Albrecht-Schmitt, Thomas E.; Haire, Richard G.

    2008-01-01

    Colorless single crystals of Gd(IO 3 ) 3 or pale pink single crystals of Er(IO 3 ) 3 have been formed from the reaction of Gd metal with H 5 IO 6 or Er metal with H 5 IO 6 under hydrothermal reaction conditions at 180 deg. C. The structures of both materials adopt the Bi(IO 3 ) 3 structure type. Crystallographic data are (MoKα, λ=0.71073 A): Gd(IO 3 ) 3 , monoclinic, space group P2 1 /n, a=8.7615(3) A, b=5.9081(2) A, c=15.1232(6) A, β=96.980(1) o , V=777.03(5) Z=4, R(F)=1.68% for 119 parameters with 1930 reflections with I>2σ(I); Er(IO 3 ) 3 , monoclinic, space group P2 1 /n, a=8.6885(7) A, b=5.9538(5) A, c=14.9664(12) A, β=97.054(1) o , V=768.4(1) Z=4, R(F)=2.26% for 119 parameters with 1894 reflections with I>2σ(I). In addition to structural studies, Gd(IO 3 ) 3 , Er(IO 3 ) 3 , and the isostructural Yb(IO 3 ) 3 were also characterized by Raman spectroscopy and magnetic property measurements. The results of the Raman studies indicated that the vibrational profiles are adequately sensitive to distinguish between the structures of the iodates reported here and other lanthanide iodate systems. The magnetic measurements indicate that only in Gd(IO 3 ) 3 did the 3+ lanthanide ion exhibit its full 7.9 μ B Hund's rule moment; Er 3+ and Yb 3+ exhibited ground state moments and gap energy scales of 8.3 μ B /70 K and 3.8 μ B /160 K, respectively. Er(IO 3 ) 3 exhibited extremely weak ferromagnetic correlations (+0.4 K), while the magnetic ions in Gd(IO 3 ) 3 and Yb(IO 3 ) 3 were fully non-interacting within the resolution of our measurements (∼0.2 K). - Graphical abstract: Three f-element iodates Ln(IO 3 ) 3 (Ln=Gd, Er, Yb), all containing the Bi(IO 3 ) 3 structure type, were characterized by Raman spectroscopy and magnetic property measurements. The results of the Raman studies indicated that the vibrational profiles are adequately sensitive to distinguish between the structures of the iodates reported here and other lanthanide iodate systems. The magnetic

  5. Magnetic and electrical properties of the stannides RE sub 3 Co sub 6 Sn sub 5 (RE Sm, Gd, Tb and Dy)

    CERN Document Server

    Kaczorowski, D; Rogl, P; Romaka, L; Gorelenko, Y

    2003-01-01

    Polycrystalline samples of the ternary intermetallics RE sub 3 Co sub 6 Sn sub 5 (RE Sm, Gd, Tb and Dy) were studied by means of magnetization, dc magnetic susceptibility and electrical resistivity measurements. All these stannides were found to order magnetically at low temperatures. Sm sub 3 Co sub 6 Sn sub 5 is antiferromagnetic below T sub N = 8 K, while Tb sub 3 Co sub 6 Sn sub 5 exhibits ferromagnetic ordering below T sub C = 16 K. The other two compounds show more complex magnetic behaviour with subsequent phase transitions in the ordered regions. For Gd sub 3 Co sub 6 Sn sub 5 one observes the onset of ferromagnetism at T sub C = 25 K, which is followed by a change in the magnetic structure at T sub 1 = 12 K. In the case of Dy sub 3 Co sub 6 Sn sub 5 an antiferromagnetic type of order sets in at T sub N = 7 K, and then a spin structure rearrangement occurs at T sub 1 = 3 K that yields a ferromagnetic component at lower temperatures. All the ternaries studied exhibit metallic-like conductivity with pro...

  6. Structural and optical properties of Tb-doped Na-Gd metaphosphate glasses and glass-ceramics

    Czech Academy of Sciences Publication Activity Database

    Moretti, F.; Vedda, A.; Nikl, Martin; Nitsch, Karel

    2009-01-01

    Roč. 21, č. 15 (2009), 155103/1-155103/7 ISSN 0953-8984 R&D Projects: GA AV ČR IAA200100626 Institutional research plan: CEZ:AV0Z10100521 Keywords : Na-Gd metaphosphate glass * glass -ceramics * NaGd(PO 3 ) 4 * optical properties * structural properties * Raman spectroscopy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.964, year: 2009

  7. Luminescence characteristic of RE (RE = Pr, Sm, Eu, Tb, Dy) and energy levels of lanthanide ions in Gd5Si3O12N

    Science.gov (United States)

    Zhang, Zhi-Jun; Yang, Woochul

    2017-10-01

    Polycrystalline Gd5Si3O12N: RE (RE = Pr, Sm, Eu, Tb and Dy) phosphors have been synthesized via a solid-state reaction method at high temperature, and their photoluminescence properties were studied. The absorption peak at about 230 nm is attributed to the host absorption. For the Pr3+-doped sample, the typical excitation lines located at 273 nm originating from the 8S7/2 → 6IJ (J = 5/2, 7/2) transitions of the Gd3+ ions were observed in the excitation spectra. Upon excitation at 227 nm UV light, the 4f15d → 4f2 emission band (350-450 nm) and typical 4f2 → 4f2 emission lines (450-700 nm) assigned to Pr3+ were observed. The Sm3+-doped sample exhibits a bright red emission owing to the 4G5/2 → 6HJ (J = 5/2, 7/2 and 9/2) transitions. However, the charge transfer band of Sm3+ was not observed in the excitation spectrum. There is a broad band from 200 to 350 nm originating from the charge transfer transition (CT) of the Eu3+ (O2-/N3- → Eu3+) in the excitation spectra, and the strongest peak in the emission spectra located at 615 nm is due to the electric-dipole 5D0 → 7F2 transition of Eu3+. For the Tb3+-doped sample, it shows 5D3 →7FJ (J = 5, 4, 3, 2) blue line emissions and 5D4 → 7FJ (J = 6, 5, 4, 3) green line emissions under the excitation of Tb3+. The Dy3+-activated sample upon excitation at 349 and 386 nm UV light shows blue-green and orange-red emission lines originating from 4F9/2 → 6HJ (J = 15/2, 13/2) transitions. In addition, the energy transfer from the host lattice to the luminescence activators (i.e. Pr3+, Sm3+, Eu3+, Tb3+, Dy3+) has been confirmed. In addition, the energy level diagram including the 4f and 5d energy levels of all Ln2+ and Ln3+ ions relative to the valence and conduction band of Gd5Si3O12N were constructed and discussed.

  8. Determination of Tb, Dy, Ho, Er and Yb in ores and concentrates by ICP-OES method

    International Nuclear Information System (INIS)

    Kanicky, V.; Toman, J.; Malecek, M.

    1988-01-01

    Optical emission spectroscopy was used (OES) to analyse apatite from the Kola peninsula with a total content of 0.9% oxides of heavy rare earth elements, the hydroxide concentrate of apatite, the oxide concentrate of rare earth elements, bastnaesite minerals and raw materials containing monasite. Measurements were made with a PV 8210/8280 spectrometer (width of spectral interval in the 1st order of the spectrum 0.028 mm) and an ICP PV 8490 generator. The spectra were measured of 19 most sensitive analytical lines of heavy rare earth elements (8 Tb, 3 Dy, 1 Ho, 3 Er, 4 Yb). The mutual interferences of the different elements, detection limits and resolution limits were determined. The results of the determination of rare earth elements and of certain general elements in the analysed raw materials are tabulated. (E.S.). 2 figs., 11 tabs., 10 refs

  9. Optical emission, vibrational feature, and shear-thinning aspect of Tb3+-doped Gd2O3 nanoparticle-based novel ferrofluids irradiated by gamma photons

    Science.gov (United States)

    Paul, Nibedita; Hazarika, Samiran; Saha, Abhijit; Mohanta, Dambarudhar

    2013-10-01

    The present work reports on the spectroscopic and rheological properties of un-exposed and gamma (γ-) irradiated rare earth (RE) oxide nanoparticle-based ferrofluids (FFs). The FFs were produced by dispersing surfactant coated terbium (Tb3+)-doped gadolinium oxide (Gd2O3) nanoparticles in the ethanol medium and later on they were subjected to energetic γ-irradiation (1.25 MeV) at select doses (97 Gy and 2.635 kGy). The synthesized RE oxide nanoparticles were of ˜7 nm size and having a cubic crystal structure, as predicted from transmission electron microscopy and x-ray diffraction studies. Fourier transformed infra-red (FT-IR) spectra showed an adequate blue shift of the Gd-O vibrational stretching mode from a wavenumber value of ˜558 cm-1, for the un-irradiated sample to a value of ˜540 cm-1 corresponding to the irradiated sample (2.635 kGy). In contrast, photoluminescence spectra have revealed modification of defect states along with Tb3+ assisted radiative transitions. The rheology measurements have illustrated unusual shear thinning behavior of the FFs, with an apparently improved power index (s) value from 0.34 to 0.50, obtained for increasing γ-dose cases. The variation of the decay parameter with irradiation dose, as predicted from the nature of apparent viscosity curves, is attributed to the defect formation, role of impurity ions (Tb3+), and weakening of inter nanoparticle bonding. The unusual properties of the novel RE oxide based FFs may find scope in sealing and shielding elements in the radiation environment including accelerator and other related zones.

  10. A novel tunable blue-green-emitting CaGdGaAl2O7:Ce(3+),Tb(3+) phosphor via energy transfer for UV-excited white LEDs.

    Science.gov (United States)

    Liang, Chao; You, Hongpeng; Fu, Yibing; Teng, Xiaoming; Liu, Kai; He, Jinhua

    2015-05-07

    CaGdGaAl2O7 and CaGdGaAl2O7:Ce(3+),Tb(3+) have been synthesized by a traditional solid state reaction for the first time. The Rietveld refinement confirmed that CaGdGaAl2O7 has a tetragonal crystal system with the space group P4[combining macron]21m. The photoluminescence properties show that the obtained phosphors can be efficiently excited in the range from 330 to 400 nm, which matches perfectly with commercial UV LED chips. A tunable blue-green emitting CaGdGaAl2O7:Ce(3+),Tb(3+) phosphor has been obtained, by codoping Ce(3+) and Tb(3+) ions into the host and varying their relative ratios, and may be a good candidate for blue-green components in UV white LEDs. The luminescence properties and lifetimes reveal an efficient energy transfer from the Ce(3+) to Tb(3+) ions. The energy transfer is demonstrated to be a dipole-quadrupole mechanism, and the critical distance for Ce(3+) to Tb(3+) calculated by the concentration quenching is 12.25 Å.

  11. Crystal structure and superconductivity of LnBa2Cu4O8(Ln = Ho, Er, Y, Dy and Gd) superconductors

    International Nuclear Information System (INIS)

    Ishigaki, Toru; Mori, Kazuya; Kawaguchi, Yasuhiro; Hamaguchi, Yoshikazu; Katano, Susumu; Funahashi, Satoru.

    1993-01-01

    Bulk Superconductors of LnBa 2 Cu 4 O 8 (Ln =Er, Ho, Y, Dy and Gd) which share the 124 structure of YBa 2 Cu 4 O 8 were synthesized by using hot isostatic pressing (HIP) treatment. The crystal structure at room temperature was refined from the neutron and X-ray powder diffraction data by Rietveld analysis. T c of our samples are showed monotonous decreasing from highest 84.1 K (Ln = Er) to 77.3 K (Ln = Gd) following the ionic radius. Madelung energy calculation from refined structural parameters show the hole concentration on CuO 2 plane. These results show that the substitution of lanthanoide elements to Y site of YBa 2 Cu 4 O 8 induce 'chemical pressure' effect. (author)

  12. Synthesis, structure and properties of bimetallic sodium rare-earth (RE) borohydrides, NaRE(BH4)4, RE = Ce, Pr, Er or Gd

    DEFF Research Database (Denmark)

    Payandeh Gharibdoust, Seyedhosein; Ravnsbæk, Dorthe B.; Černý, Radovan

    2017-01-01

    Formation, stability and properties of new metal borohydrides within RE(BH4)3-NaBH4, RE = Ce, Pr, Er or Gd is investigated. Three new bimetallic sodium rare-earth borohydrides, NaCe(BH4)4, NaPr(BH4)4 and NaEr(BH4)4 are formed based on an addition reaction between NaBH4 and halide free rare-earth...... to formation of metal hydrides and possibly slower formation of sodium borohydride. The dehydrogenated state clearly contains rare-earth metal borides, which stabilize boron in the dehydrogenated state....

  13. Influence of Er3+/Yb3+ concentration ratio on the down-conversion and up-conversion luminescence and lifetime in GdVO4:Er3+/Yb3+ microcrystals

    Directory of Open Access Journals (Sweden)

    Gavrilović T.V.

    2015-01-01

    Full Text Available In this paper, we studied the effects of Er3+/Yb3+ concentration ratio on structural, morphological and luminescence properties of GdVO4:Er3+/Yb3+ green phosphors prepared by a high-temperature solid state method. The samples with different concentrations (between 0.5 to 2 mol% of dopant Er3+ emitting ions and different concentrations (between 5 to 20 mol% of sensitizer ions (Yb3+ were studied. The phosphors were characterized by the X-ray diffraction (XRD, scanning electron microscopy (SEM and photoluminescence spectroscopy. For all samples, XRD diffraction patterns confirmed a formation of a pure GdVO4 phase, while the SEM showed that the materials are comprised of chunks of deformed particles with an average diameter ranging from approximately 2 μm to 8 μm. Both, down-conversion and up-conversion emission spectra of GdVO4:Er3+/Yb3+ samples, under near UV and IR excitations, exhibit two strong emission bands in the green spectral region at 525 nm and 552 nm wavelengths corresponding to 2H11/2 →4I15/2 and 4S3/2 → 4I15/2 electronic transitions of Er3+ ions. The intensity of the green emission was changed by changing the Er3+/Yb3+ concentration ratio. This dual-mode luminescence makes these materials ideal as green phosphors for a wide variety of applications in the fields of bioanalysis and biomedical. [Projekat Ministarstva nauke Republike Srbije, br. 45020 i br. 172056

  14. Structural characterization of Er(3+),Yb(3+)-doped Gd2O3 phosphor, synthesized using the solid-state reaction method, and its luminescence behavior.

    Science.gov (United States)

    Tamrakar, Raunak Kumar; Bisen, D P; Brahme, Nameeta

    2016-02-01

    We report the synthesis and structural characterization of Er(3+),Yb(3+)-doped Gd2O3 phosphor. The sample was prepared using the conventional solid-state reaction method, which is the most suitable method for large-scale production. The prepared phosphor sample was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), thermoluminescence (TL), photoluminescence (PL) and CIE techniques. For PL studies, the excitation and emission spectra of Gd2O3 phosphor doped with Er(3+) and Yb(3+) were recorded. The excitation spectrum was recorded at a wavelength of 551 nm and showed an intense peak at 276 nm. The emission spectrum was recorded at 276 nm excitation and showed peaks in all blue, green and red regions, which indicate that the prepared phosphor may act as a single host for white light-emitting diode (WLED) applications, as verified by International de I'Eclairage (CIE) techniques. From the XRD data, the calculated average crystallite size of Er(3+) and Yb(3+) -doped Gd2O3 phosphor is ~ 38 nm. A TL study was carried out for the phosphor using UV irradiation. The TL glow curve was recorded for UV, beta and gamma irradiations, and the kinetic parameters were also calculated. In addition, the trap parameters of the prepared phosphor were also studied using computerized glow curve deconvolution (CGCD). Copyright © 2015 John Wiley & Sons, Ltd.

  15. Ternary rhombohedral Laves phases RE{sub 2}Rh{sub 3}Ga (RE = Y, La-Nd, Sm, Gd-Er)

    Energy Technology Data Exchange (ETDEWEB)

    Seidel, Stefan; Benndorf, Christopher; Heletta, Lukas; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Janka, Oliver [Oldenburg Univ. (Germany). Inst. fuer Chemie; Mausolf, Bernhard [RWTH Aachen (Germany). Inst. fuer Anorganische Chemie; Haarmann, Frank [RWTH Aachen (Germany). Inst. fuer Anorganische Chemie; Max-Planck-Institut fuer Chemische Physik fester Stoffe, Dresden (Germany); Eckert, Hellmut [Muenster Univ. (Germany). Inst. fuer Physikalische Chemie; Sao Paulo Univ., Sao Carlos (Brazil). Inst. of Physics

    2017-06-01

    The ordered Laves phases RE{sub 2}Rh{sub 3}Ga (RE=Y, La-Nd, Sm, Gd-Er) were synthesized by arc-melting of the elements and subsequent annealing. The samples were characterized by powder X-ray diffraction (XRD). They crystallize with the rhombohedral Mg{sub 2}Ni{sub 3}Si type structure, space group R3m. Three structures were refined from single crystal X-ray diffractometer data: a=557.1(1), c=1183.1(2), wR2=0.0591, 159 F{sup 2} values, 10 variables for Y{sub 2}Rh{sub 3}Ga, a=562.5(2), c=1194.4(2) pm, wR2=0.0519, 206 F{sup 2} values, 11 variables for Ce{sub 2}Rh{sub 3}Ga and a=556.7(2), c=1184.1(3) pm, wR2=0.0396, 176 F{sup 2} values, 11 variables for Tb{sub 2}Rh{sub 3}Ga. The Rh{sub 3}Ga tetrahedra are condensed via common corners and the large cavities left by the network are filled by the rare earth atoms. The RE{sub 2}Rh{sub 3}Ga Laves phases crystallize with a translationengleiche subgroup of the cubic RERh{sub 2} Laves phases with MgCu{sub 2} type. Magnetic susceptibility measurements reveal Pauli paramagnetism for Y{sub 2}Rh{sub 3}Ga and La{sub 2}Rh{sub 3}Ga. Ce{sub 2}Rh{sub 3}Ga shows intermediate cerium valence while all other RE{sub 2}Rh{sub 3}Ga phases are Curie-Weiss paramagnets which order magnetically at low temperatures. The {sup 89}Y and {sup 71}Ga solid state nuclear magnetic resonance (NMR) spectra of the diamagnetic representative Y{sub 2}Rh{sub 3}Ga show well-defined single resonances in agreement with an ordered bulk phase. In comparison to the binary Laves phase YRh{sub 2} a strongly increased {sup 89}Y resonance frequency is observed owing to a higher s-electron spin density at the {sup 89}Y nuclei as proven by density of states (DOS) calculations.

  16. A single crystal study of RE{sub 14}Co{sub 3}In{sub 3} (RE = Y, Tb, Dy, Ho, Er)

    Energy Technology Data Exchange (ETDEWEB)

    Zaremba, V.I.; Kalychak, Y.M.; Dzevenko, M.V. [Inorganic Chemistry Dept., Ivan Franko National Univ. of Lviv (Ukraine); Rodewald, U.Ch.; Heying, B.; Poettgen, R. [Inst. fuer Anorganische und Analytische Chemie, Westfaelische Wilhelms-Univ. Muenster (Germany)

    2006-01-01

    The rare earth-cobalt-indides RE{sub 14}Co{sub 3}In{sub 3} (RE = Y, Tb, Dy, Ho, Er) were prepared in polycrystalline form from the elements by arc-melting. Small single crystals were grown through a special annealing sequence. The compounds were investigated on the basis of X-ray powder and single crystal data: Lu{sub 14}Co{sub 2}In{sub 3} (Gd{sub 14}Co{sub 3}In{sub 2.7}) type, P4{sub 2}/nmc, Z = 4, a = 959.0(1), c = 2319.1(5) pm, wR2 = 0.055, 2289 F{sup 2} values, 65 variables for Y{sub 13.90}Co{sub 2.99}In{sub 3.02}, a = 953.8(1), c = 2315.8(5) pm, wR2 = 0.108, 2357 F{sup 2} values, 65 variables for Tb{sub 13.92}Co{sub 3.01}In{sub 2.92}, a = 949.24(3), c = 2296.5(1) pm, wR2 = 0.129, 2518 F{sup 2} values, 65 variables for Dy{sub 13.90}Co{sub 2.97}In{sub 2.95}, a = 946.3(1), c = 2289.0(5) pm, wR2 = 0.099, 2297 F{sup 2} values, 64 variables for Ho{sub 14}Co{sub 2.80}In{sub 2.89}, and a = 941.0(1), c = 2274.2(5) pm, wR2 = 0.140, 2450 F{sup 2} values, 65 variables for Er{sub 13.83}Co{sub 2.88}In{sub 3.10}. All RE{sub 14}Co{sub 3}In{sub 3} indides show a small degree of In/Co mixing (between 7 and 16% Co) on the 4c In1 site and defects on the 8g Co1 positions (between 84 and 95% Co). Except for the holmium compound, the RE{sub 14}Co{sub 3}In{sub 3} intermetallics also reveal RE/In mixing on the 4c RE1 sites, leading to the refined compositions. The seven crystallographically independent RE sites have between 9 and 10 nearest RE neighbors. The RE{sub 14}Co{sub 3}In{sub 3} structures consist of a complex intergrowth of rare earth based polyhedra. Both cobalt sites have a distorted trigonal-prismatic rare earth coordination. An interesting feature is the In2-In2 dumb-bell with an In2-In2 distance of 300 pm (for Ho{sub 14}Co{sub 2.80}In{sub 2.89}). The crystal chemistry of the RE{sub 14}Co{sub 3}In{sub 3} indides is discussed. (orig.)

  17. Preparation and characterization of electroluminescent devices based on complexes of β-diketonates of Tb3+, Eu3+, Gd3+ ions with macrocyclic ligands and UO22+ films

    International Nuclear Information System (INIS)

    Gibelli, Edison Bessa

    2010-01-01

    Complexes containing Rare Earth ions are of great interest in the manufacture of electro luminescent devices as organic light emitting devices (OLED). These devices, using rare earth trivalent ions (TR 3+ ) as emitting centers, show high luminescence with extremely fine spectral bands due to the structure of their energy levels, long life time and high quantum efficiency. This work reports the preparation of Rare Earth β-diketonate complexes (Tb 3+ , Eu 3+ and Gd 3+ ) and (tta - thenoyltrifluoroacetonate and acac - acetylacetonate) containing a ligand macrocyclic crown ether (DB18C6 - dibenzo18coroa6) and polymer films of UO 2 2+ . The materials were characterized by complexometric titration with EDTA, CH elemental analysis, near infrared absorption spectroscopy, thermal analysis, X-ray diffraction (powder method) and luminescence spectroscopy. For manufacturing the OLED it was used the technique of deposition of thin films by physical vapor (PVD, Physical Vapor Deposition). (author)

  18. Thermal decomposition of RE(C2H5CO2)3·H2O (RE = Dy, Tb, Gd, Eu and Sm)

    DEFF Research Database (Denmark)

    Grivel, Jean-Claude

    2014-01-01

    The thermal decomposition of Dy(III), Tb(III), Gd(III), Eu(III), and Sm(III) propionate monohydrates was studied in argon by means of simultaneous differential thermal analysis and thermogravimetry, infrared-spectroscopy, X-ray diffraction, and optical microscopy. After dehydration, which takes p...

  19. Platinum triangles in the Pt/Al framework of the intermetallic REPt{sub 6}Al{sub 3} (RE = Ce-Nd, Sm, Gd, Tb) series

    Energy Technology Data Exchange (ETDEWEB)

    Eustermann, Fabian; Stegemann, Frank; Renner, Konstantin [Institut fuer Anorganische und Analytische Chemie, Westfaelische Wilhelms-Universitaet Muenster (Germany); Janka, Oliver [Institut fuer Anorganische und Analytische Chemie, Westfaelische Wilhelms-Universitaet Muenster (Germany); Institut fuer Chemie, Carl von Ossietzky Universitaet Oldenburg (Germany)

    2017-12-13

    The compounds of the REPt{sub 6}Al{sub 3} series (RE = Ce-Nd, Sm, Gd, Tb) were obtained by reaction of the elements via arc-melting. They were characterized by powder and single-crystal X-ray diffraction (NdPt{sub 6}Al{sub 3}: wR = 0.0432, 759 F{sup 2} values, 33 variables) as well as by magnetic susceptibility measurements. The isostructural compounds crystallize with a new structure type in the trigonal crystal system with space group R anti 3c, twelve formula units in the unit cell, and lattice parameters of a = 752-755 and c = 3882-3945 pm. The crystal structure can be described by different slabs stacked along [001]. One layer features Pt{sub 3} triangles, centering the cavities of a flat honeycomb RE layer that are arranged in a..ABCA{sup '}B{sup '}C{sup '}.. sequence. The other layer consists of condensed hexagonal [Pt{sub 6}Al{sub 6}] prisms, centered by Pt atoms, separating the before mentioned slabs. Magnetic measurements revealed that all rare-earth atoms are in the trivalent oxidation state, however, due to the low lanthanoide content magnetic ordering phenomena were observed only at low temperatures [SmPt{sub 6}Al{sub 3}: T{sub C} = 5.0(1) K; GdPt{sub 6}Al{sub 3}: T{sub C} = 7.3(1) K; TbPt{sub 6}Al{sub 3}: T{sub N} = 3.6(1) K]. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Crystal fields in Sc, Y, and the heavy-rare-earth metals Tb, Dy, Ho, Er, Tm, and Lu

    International Nuclear Information System (INIS)

    Touborg, P.

    1977-01-01

    Experimental investigations of the magnetic poperties of dilute alloys of the rare-earth solutes Tb, Dy, Ho, Er, and Tm in the nonmagnetic hosts Lu, Y, and Sc have been performed. These measurements, which include and supplement earlier published results, have been analyzed and crystal-field parameters for all these 15 alloy systems deduced. The consistency of the parameters was confirmed by a variety of magnetic measurements, including neutron spectroscopy. Crystal-field parameters have also been derived for the ions in pure magnetic rare-earth metals and their alloys using the results for the dilute alloys supplemented with paramagnetic measurements up to high temperatures on the concentrated systems. Mean values and standard deviations of the higher-order crystal-field parameters for all Y and Lu alloys are B 40 /β = 6.8 +- 0.9 K, B 60 /γ = 13.6 +- 0.7 K, and B 66 /γ = (9.7 +- 1.1) B 60 /γ. These values: with the inaccuracies somewhat increased: are expected to be representative also for the magnetic rare-earth metals. For rare-earth ions in the Sc host the values B 40 /β = 9.9 +- 1.9 K, B 60 /γ = 19.8 +- 1.5 K, and B 66 /γ = (9.4 +- 0.9) B 60 /γ were deduced. B 20 /α is a host-sensitive parameter which has the average values of -102.7, -53.4, and 29.5 K for rare-earth ions in Y, Lu, and Sc, respectively. There is also evidence that this parameter varies with the solute. B 20 /α for ions in the pure magnetic rare-earth metals and their alloys shows a linear variation with c/a ratio characteristic of each ion. The results indicate a contribution from anisotropic exchange to the high-temperature paramagnetic anisotropy of approximately 20% for Tb, Dy, Ho, and Er, and approximately 10% for Tm

  1. Folic acid-conjugated GdPO{sub 4}:Tb{sup 3+}@SiO{sub 2} Nanoprobe for folate receptor-targeted optical and magnetic resonance bi-modal imaging

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Xianzhu [Jiangxi Normal University, College of Life Science, Jiangxi Provincial Key Laboratory of Protection and Utilization of Subtropical Plant Resources of Jiangxi Province (China); Zhang, Xiaoying; Wu, Yanli, E-mail: Wanny118@126.com [Jiangxi Science and Technology Normal University, Jiangxi Key Laboratory of Organic Chemistry (China)

    2016-11-15

    Both fluorescent and magnetic nanoprobes have great potential applications for diagnostics and therapy. In the present work, a folic acid-conjugated and silica-modified GdPO{sub 4}:Tb{sup 3+} (GdPO{sub 4}:Tb{sup 3+}@SiO{sub 2}-FA) dual nanoprobe was strategically designed and synthesized for the targeted dual-modality optical and magnetic resonance (MR) imaging via a facile aqueous method. Their structural, optical, and magnetic properties were determined using transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR), ultraviolet-visible spectra (UV-Vis), photoluminescence (PL), and superconducting quantum interference device (SQUID). These results indicated that GdPO{sub 4}:Tb{sup 3+}@SiO{sub 2}-FA were uniform monodisperse core-shell structured nanorods (NRs) with an average length of ~200 nm and an average width of ~25 nm. The paramagnetic property of the synthesized GdPO{sub 4}:Tb{sup 3+}@SiO{sub 2}-FA NRs was confirmed with its linear hysteresis plot (M-H). In addition, the NRs displayed an obvious T{sub 1}-weighted effect and thus it could potentially serve as a T{sub 1}-positive contrast agent. The NRs emitted green lights due to the {sup 5}D{sub 4} → {sup 7}F{sub 5} transition of the Tb{sup 3+}. The in vitro assays with NCI-H460 lung cancer cells and human embryonic kidney cell line 293T cells indicated that the GdPO{sub 4}:Tb{sup 3+}@SiO{sub 2}-FA nanoprobe could specifically bind the cells bearing folate receptors (FR). The MTT assay of the NRs revealed that its cytotoxicity was very low. Further in vivo MRI experiments distinctively depict enhanced anatomical features in a xenograft tumor. These results suggest that the GdPO{sub 4}:Tb{sup 3+}@SiO{sub 2}-FA NPs have excellent imaging and cell-targeting abilities for the folate receptor-targeted dual-modality optical and MR imaging and can be potentially used as the nanoprobe for bioimaging.

  2. Nuclear and magnetic medium range order in amorphous Tb65Cu35 and Er69.5Cu30.5 alloys

    International Nuclear Information System (INIS)

    Boucher, B.; Sanquer, M.; Tourbot, R.

    1989-01-01

    Small angle neutron scattering on amorphous and mechanical polished Tb 65 Cu 35 and Er 69.5 Cu 30.5 alloys has been measured at different temperatures between 4 and 300K on samples cooled in zero or in applied magnetic fields. The isotropic scattering is analyzed quantitatively in terms of spatial variations of chemical concentration or magnetization. The influence of the magnetic field is discussed

  3. Subsolidus Phase Relations of the CaO-REOx-CuO Systems (RE = Eu, Tb, Dy, Ho, Er, Lu and Sc) at 900 °C in Air

    DEFF Research Database (Denmark)

    Grivel, Jean-Claude

    2016-01-01

    The subsolidus phase relations of the CaO-REOx-CuO systems (RE = Eu, Tb, Dy, Ho, Er, Lu and Sc) were investigated in air at 900 °C. The pseudo-ternary sections with RE = Tb, Dy, Ho, Er and Lu have a similar structure. They have in common with the RE = Eu system a solid solution of Ca0.833−xRExCuO2......+y composition but the system with RE = Eu differs by the presence of an Eu2CuO4 phase instead of RE2Cu2O5 for RE = Tb, Dy, Ho, Er and Lu. In contrast, the CaO-ScO1.5-CuO section does not contain a Ca0.833−xScxCuO2+y solid solution and is dominated by the CaSc2O4 phase, which has no equivalent...... in the other systems at 900 °C in air....

  4. Magnetic properties and magnetocaloric effect in the R{sub 2}PdSi{sub 3} (R = Gd, Dy and Er) compounds

    Energy Technology Data Exchange (ETDEWEB)

    Mo, Zhao Jun, E-mail: mozhaojun@iphy.ac.cn [School of Material Science and Engineering, Tianjin University of Technology, Tianjin (China); Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing (China); Shen, Jun, E-mail: jshen@mail.ipc.ac.cn [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing (China); Gao, Xin Qiang [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing (China); Liu, Yao [State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter, Physics and Institute of Physics, Chinese Academy of Sciences, Beijing (China); Tang, Cheng Chun [School of Material Science and Engineering, Hebei University of Technology, Tianjin (China); Wu, Jian Feng [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing (China); Hu, Feng Xia; Sun, Ji Rong; Shen, Bao Gen [State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter, Physics and Institute of Physics, Chinese Academy of Sciences, Beijing (China)

    2015-03-25

    Highlights: • Er{sub 2}PdSi{sub 3} compound exhibits a giant reversible MCE. • Er{sub 2}PdSi{sub 3} compound’s MCEs show no thermal and magnetic hysteresis. • Under field changes of 2 T, the value of -ΔS{sub M}{sup max} is 14.5 J/kg K and the RC is 111 J/kg, respectively. - Abstract: The magnetic properties and magnetocaloric effect in R{sub 2}PdSi{sub 3} (R = Dy, Dy and Er) compounds have been investigated. All these compounds possess an antiferromagnetic (AFM)-paramagnetic (PM) transition around their respective Néel temperatures. And, it is found that the Dy{sub 2}PdSi{sub 3} and Er{sub 2}PdSi{sub 3} compounds undergo a spin-glass behavior below Néel temperature. Under the magnetic field change of 5 T, the values of -ΔS{sub M}{sup max} reach 11.8 J/kg K for Gd{sub 2}PdSi{sub 3}, 16.6 J/kg K for Dy{sub 2}PdSi{sub 3} and 22 J/kg K for Er{sub 2}PdSi{sub 3}, respectively. Especially, the values of -ΔS{sub M}{sup max} in the Er{sub 2}PdSi{sub 3} compound are 8 and 14.5 J/kg K for field change of 1 and 2 T, which is attributed to a field-induced metamagnetic transition from AFM to FM states. The large reversible -ΔS{sub M} and large RC together with the absence of thermal and field hysteresis indicate that Er{sub 2}PdSi{sub 3} compound could be a promising candidate for magnetic refrigeration at low temperatures.

  5. Rhodium-rich silicides RERh{sub 6}Si{sub 4} (RE=La, Nd, Tb, Dy, Er, Yb)

    Energy Technology Data Exchange (ETDEWEB)

    Vosswinkel, Daniel; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie

    2017-07-01

    Polycrystalline RERh{sub 6}Si{sub 4} (RE=La, Nd, Tb, Dy, Er, Yb) samples can be synthesized by arc-melting of the elements. Single crystals of LaRh{sub 6}Si{sub 4}, NdRh{sub 6}Si{sub 4} and YbRh{sub 6}Si{sub 4} were synthesized from the elements in bismuth fluxes (non-reactive flux medium). The structures were refined on the basis of single-crystal X-ray diffractometer data: LiCo{sub 6}P{sub 4} type, P anti 6m2, a=700.56(3), c=380.55(1) pm, wR2=0.0257, 317 F{sup 2} values, 19 variables for LaRh{sub 6}Si{sub 4}, a=698.4(5), c=377.7(2) pm, wR2=0.0578, 219 F{sup 2} values, 19 variables for NdRh{sub 6}Si{sub 4} and a=696.00(3), c=371.97(1) pm, wR2=0.0440, 309 F{sup 2} values, 19 variables for YbRh{sub 6}Si{sub 4}. The rhodium and silicon atoms build up three-dimensional, covalently bonded [Rh{sub 6}Si{sub 4}]{sup δ-} polyanionic networks with Rh-Si distances ranging from 239 to 249 pm. The rare earth atoms fill larger cavities within channels of these networks and they are coordinated by six silicon and twelve rhodium atoms in the form of hexa-capped hexagonal prisms.

  6. Structural elucidation and magnetic behavior evaluation of rare earth (La, Nd, Gd, Tb, Dy) doped BaCoNi-X hexagonal nano-sized ferrites

    Energy Technology Data Exchange (ETDEWEB)

    Majeed, Abdul, E-mail: abdulmajeed2276@gmail.com [Department of Physics, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Khan, Muhammad Azhar, E-mail: azhar.khan@iub.edu.pk [Department of Physics, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Raheem, Faseeh ur; Hussain, Altaf; Iqbal, F. [Department of Physics, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Murtaza, Ghulam [Centre for Advanced Studies in Physics, Government College University, Lahore 54000 (Pakistan); Akhtar, Majid Niaz [Department of Physics, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan); Shakir, Imran [Deanship of Scientific Research, College of Engineering, King Saud University, PO Box 800, Riyadh 11421 (Saudi Arabia); Warsi, Muhammad Farooq [Department of Chemistry, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan)

    2016-06-15

    Rare-earth (RE=La{sup 3+}, Nd{sup 3+}, Gd{sup 3+}, Tb{sup 3+}, Dy{sup 3+}) doped Ba{sub 2}NiCoRE{sub x}Fe{sub 28−x}O{sub 46} (x=0.25) hexagonal ferrites were synthesized for the first time via micro-emulsion route, which is a fast chemistry route for obtaining nano-sized ferrite powders. These nanomaterials were investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), as well as vibrating sample magnetometer (VSM). The XRD analysis exhibited that all the samples crystallized into single X-type hexagonal phase. The crystalline size calculated by Scherrer's formula was found in the range 7–19 nm. The variations in lattice parameters elucidated the incorporation of rare-earth cations in these nanomaterials. FTIR absorption spectra of these X-type ferrites were investigated in the wave number range 500–2400 cm{sup −1.} Each spectrum exhibited absorption bands in the low wave number range, thereby confirming the X-type hexagonal structure. The enhancement in the coercivity was observed with the doping of rare-earth cations. The saturation magnetization was lowered owing to the redistribution of rare-earth cations on the octahedral site (3b{sub VI}). The higher values of coercivity (664–926 Oe) of these nanomaterials suggest their use in longitudinal recording media. - Graphical abstract: Nano-sized rare-earth (RE=La{sup 3+}, Nd{sup 3+}, Gd{sup 3+}, Tb{sup 3+}, Dy{sup 3+}) doped Ba{sub 2}NiCoRE{sub x}Fe{sub 28−x}O{sub 46} (x=0.25) hexagonal ferrites were synthesized for the first time via micro-emulsion route and the crystallite size was found in the range 7–19 nm. The enhancement in the coercivity was observed with the doping of rare-earth cations. The higher values of coercivity (664–926 Oe) of these nanomaterials suggest their use in longitudinal recording media. - Highlights: • Micro-emulsion route was used to synthesize Ba{sub 2}NiCoRE{sub x}Fe{sub 28−x}O{sub 46} ferrites. • The crystallite size was found

  7. Positron annihilation studies in high-Tc superconductors RBa2Cu3Oy, R: La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Er

    International Nuclear Information System (INIS)

    Lagouri, T.; Dedoussis, S.; Chardalas, M.; Liolios, A.

    1997-01-01

    Positron lifetime and Doppler broadening of the annihilation line measurements have been performed at room temperature in high-T c superconductors RBa 2 Cu 3 O y , where R: La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Er and 6.9 c superconducting samples RBa 2 Cu 3 O y , where R: Nd, Sm, Eu, Ho, Y, Er as a function of temperature between 14 K and 293 K. It was observed that the positron lifetime and the S parameter values at room temperature have no obvious trend in their variation from the yttrium substitution by a rare-earth element. It was also observed that the temperature dependence of the positron annihilation parameters is similar in the high-T c superconducting samples. (orig.)

  8. First-principles calculation of structural and energetic properties for A2Ti2O7 (A = Lu, Er, Y, Gd, Sm, Nd, La)

    International Nuclear Information System (INIS)

    Zhang, Z.L.; Xiao, H.Y.; Zu, Xiaotao T.; Gao, Fei; Weber, William J.

    2009-01-01

    A first-principles method has been employed to investigate the structural and energetic properties for A2Ti2O7 (A = Lu, Er, Y, Gd, Sm, Nd, La), including the formation energies of the cation antisite-pair, the anion Frenkel pair that defines anion-disorder, and the coupled cation antisite-pair/anion-Frenkel. It is proposed that the interaction may have more significant influence on the radiation resistance behavior of titanate pyrochlores, although the interactions are relatively much stronger than the interactions. It is found that the defect formation energies are not simple functions of the A-site cation radii. The formation energy of the cation antisite-pair increases continuously as the A-site cation varies from Lu to Gd, and then decreases continuously with the variation of the A-site cation from Gd to La, in excellent agreement with the radiation-resistance trend of the titanate pyrochlores. The band gaps in these pyrochlores were also measured, and the band gap widths changed continuously with cation radius.

  9. Synthesis under ambient pressure and tri-axial magnetic orientation in REBa2Cu4O8 (RE = Y, Sm, Eu, Gd, Dy, Ho, Er)

    International Nuclear Information System (INIS)

    Yamaki, M.; Horii, S.; Haruta, M.; Maeda, T.; Shimoyama, J.

    2011-01-01

    REBa 2 Cu 4 O 8 (RE124) was synthesized by a flux method in ambient pressure for RE = Y, Sm, Eu, Gd, Dy, Ho and Er. Tri-axial orientation of RE124 was achieved in a modulated rotating magnetic field of 10 T. Orientation axes in RE124 depended on the type of RE. Magnetization axes were determined from magnetic anisotropies of Cu and RE ions. We report the rare-earth (RE)-dependent magnetization axes of REBa 2 Cu 4 O 8 , which was synthesized by a flux method under ambient pressure, using powder samples tri-axially oriented in a modulated rotating magnetic field of 10 T. By optimizing the growth temperature and cooling rate, RE124 crystals were successfully grown for RE = Y, Sm, Eu, Gd, Dy, Ho, and Er. From the X-ray diffraction measurement, the magnetically oriented directions were largely dependent on the type of RE ions of RE124. However, the tri-axial magnetic anisotropies of RE124 could be qualitatively understood in terms of the magnitude relation between the single-ion magnetic anisotropy of RE 3+ ions and the magnetic anisotropy generated by the CuO 2 plane and Cu-O chain. For the practical use of this magneto-scientific process, the control of magnetization axes and tri-axial magnetic anisotropies through crystallochemical control is indispensable.

  10. A co-precipitation preparation, crystal structure and photoluminescent properties of Er5%:Gd{sub 2}O{sub 3} nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Boopathi, G., E-mail: psixboopathi@gmail.com; Mohan, R. [Department of Physics, Presidency College, Chennai - 600 005 (India); Raj, S. Gokul [Department of Physics, VEL TECH UNIVERSITY, Avadi, Chennai - 600 062 (India); Kumar, G. Ramesh [Department of Physics, University College of Engineering Arni, Anna University Chennai, Arni - 632 317 (India)

    2015-06-24

    An inexpensive preparation method is being reported for obtaining erbium doped gadolinium oxide (Er5%:Gd{sub 2}O{sub 3}) nanoscale rods. The elongated nanoscale systems, as-formed through a co-precipitation process, are characterized by using X-ray powder diffraction (XRD) patterns, scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) mapping, Ultra Violet-visible (UV-vis.) absorption spectroscopy and photoluminescence (PL) spectroscopy. In addition, the Williamson–Hall (W–H) plot is also performed to distinguish the effect of crystalline size-induced broadening and strain-induced broadening at full-width at half-maximum (FWHM) of the XRD profile. The XRD patterns of as-formed and calcined products show that the phase confirmation. As revealed from the SEM micrographs, the morphology of the products show that the rod-like nanoparticles. The EDX micrographs show that the presence of elements in our samples. The band gap values in calcined samples are found to be in the range of 3.569 eV. Upon 230 nm excitation on calcined samples, three broad emission peaks are observed from PL studies. The possible mechanism for the formation of Er5%:Gd{sub 2}O{sub 3} nanorods is briefly discussed.

  11. Thermal, Spectral and Laser Properties of Er3+:Yb3+:GdMgB₅O10: A New Crystal for 1.5 μm Lasers.

    Science.gov (United States)

    Huang, Yisheng; Yuan, Feifei; Sun, Shijia; Lin, Zhoubin; Zhang, Lizhen

    2017-12-25

    A novel laser crystal of Er 3+ :Yb 3+ :GdMgB₅O 10 with dimension of 26 × 16 × 12 mm³ was grown successfully from K₂Mo₃O 10 flux by the top seeded solution growth method. The thermal diffusivity and specific heat capacity were measured to calculate the thermal conductivity of the crystal. The absorption and fluorescence properties of the crystal at room temperature were investigated in detail. The Judd-Ofelt method was used to analyze the polarized absorption spectra. The emission cross-section of the ⁴I 13/2 →⁴I 15/2 transition was calculated by the Füchtbauer-Ladenburg formula and the relevant gain cross-sections were estimated. Continuous-wave laser output of 140 mW at 1569 nm with the slope efficiency of 17.8% was demonstrated in a plano-concave resonator. The results reveal that Er 3+ :Yb 3+ :GdMgB₅O 10 crystal is a promising material for 1.5 μm lasers.

  12. Thermal, Spectral and Laser Properties of Er3+:Yb3+:GdMgB5O10: A New Crystal for 1.5 μm Lasers

    Directory of Open Access Journals (Sweden)

    Yisheng Huang

    2017-12-01

    Full Text Available A novel laser crystal of Er3+:Yb3+:GdMgB5O10 with dimension of 26 × 16 × 12 mm3 was grown successfully from K2Mo3O10 flux by the top seeded solution growth method. The thermal diffusivity and specific heat capacity were measured to calculate the thermal conductivity of the crystal. The absorption and fluorescence properties of the crystal at room temperature were investigated in detail. The Judd-Ofelt method was used to analyze the polarized absorption spectra. The emission cross-section of the 4I13/2→4I15/2 transition was calculated by the Füchtbauer-Ladenburg formula and the relevant gain cross-sections were estimated. Continuous-wave laser output of 140 mW at 1569 nm with the slope efficiency of 17.8% was demonstrated in a plano-concave resonator. The results reveal that Er3+:Yb3+:GdMgB5O10 crystal is a promising material for 1.5 μm lasers.

  13. Hyperfine interaction study in RCoO3 (R = Gd and Tb) and HfO2 thin film oxides by perturbed angular correlation technique

    International Nuclear Information System (INIS)

    Cavalcante, Fabio Henrique de Moraes

    2009-01-01

    In the present work, the Perturbed Angular Gamma-Gamma Correlation technique (PAC) was used to measure the Electric Field Gradient (EFG) in two oxide systems: RCoO 3 (R = Gd, Tb) perovskite oxide and HfO 2 in order to study the behavior of the EFG as a function of temperature. Electric quadrupole hyperfine interaction measurements were carried out using 111 In → 111 Cd and 181 Hf → 181 Ta radioactive probe nuclei. The samples were prepared through a chemical route known as Sol-Gel technique and analyzed with x-ray diffraction. Both nuclei were introduced in to the perovskite samples during the chemical procedure. The thin films were provided by the Laboratory of Hyperfine Interactions at the University of 181 Hf Lisbon and the probe nuclei was activated by the irradiation of the thin film in the reactor of IPEN IEA-R1 at an appropriate time regarding the thickness of the film. The measurements were taken in the temperature range from 4 K to 1560 K. The results for the perovskite oxides measurements show a site-dependence of the EFG with probe-nuclei occupation and a temperature dependence of EFG that can be explained if spins transitions in Co are considered. The results of EFG measurements in the 25 nm thin film of HfO 2 show a second fraction besides that corresponding to bulk. (author)

  14. Luminescent and laser properties of Yb Er:GdCa4O(BO3)3: a new crystal for eye-safe 1.5-μm lasers

    Science.gov (United States)

    Denker, B.; Galagan, B.; Ivleva, L.; Osiko, V.; Sverchkov, S.; Voronina, I.; Hellstrom, J. E.; Karlsson, G.; Laurell, F.

    2004-09-01

    We present for the first time 1.5-μm laser emission in Yb Er:GdCa4O(BO3)3 (GdCOB). The crystals were grown by the Czochralski method from platinum crucibles. Spectroscopic and laser tests of the crystals are described. A continuous-wave output power of 80 mW was achieved in a monolithic microchip cavity under laser-diode pumping.

  15. Single-step synthesis of Er3+ and Yb3+ ions doped molybdate/Gd2O3 core–shell nanoparticles for biomedical imaging

    Science.gov (United States)

    Kamińska, Izabela; Elbaum, Danek; Sikora, Bożena; Kowalik, Przemysław; Mikulski, Jakub; Felcyn, Zofia; Samol, Piotr; Wojciechowski, Tomasz; Minikayev, Roman; Paszkowicz, Wojciech; Zaleszczyk, Wojciech; Szewczyk, Maciej; Konopka, Anna; Gruzeł, Grzegorz; Pawlyta, Mirosława; Donten, Mikołaj; Ciszak, Kamil; Zajdel, Karolina; Frontczak-Baniewicz, Małgorzata; Stępień, Piotr; Łapiński, Mariusz; Wilczyński, Grzegorz; Fronc, Krzysztof

    2018-01-01

    Nanostructures as color-tunable luminescent markers have become major, promising tools for bioimaging and biosensing. In this paper separated molybdate/Gd2O3 doped rare earth ions (erbium, Er3+ and ytterbium, Yb3+) core–shell nanoparticles (NPs), were fabricated by a one-step homogeneous precipitation process. Emission properties were studied by cathodo- and photoluminescence. Scanning electron and transmission electron microscopes were used to visualize and determine the size and shape of the NPs. Spherical NPs were obtained. Their core–shell structures were confirmed by x-ray diffraction and energy-dispersive x-ray spectroscopy measurements. We postulated that the molybdate rich core is formed due to high segregation coefficient of the Mo ion during the precipitation. The calcination process resulted in crystallization of δ/ξ (core/shell) NP doped Er and Yb ions, where δ—gadolinium molybdates and ξ—molybdates or gadolinium oxide. We confirmed two different upconversion mechanisms. In the presence of molybdenum ions, in the core of the NPs, Yb3+–{{{{MoO}}}4}2- (∣2F7/2, 3T2〉) dimers were formed. As a result of a two 980 nm photon absorption by the dimer, we observed enhanced green luminescence in the upconversion process. However, for the shell formed by the Gd2O3:Er, Yb NPs (without the Mo ions), the typical energy transfer upconversion takes place, which results in red luminescence. We demonstrated that the NPs were transported into cytosol of the HeLa and astrocytes cells by endocytosis. The core–shell NPs are sensitive sensors for the environment prevailing inside (shorter luminescence decay) and outside (longer luminescence decay) of the tested cells. The toxicity of the NPs was examined using MTT assay.

  16. Single-step synthesis of Er3+and Yb3+ions doped molybdate/Gd2O3core-shell nanoparticles for biomedical imaging.

    Science.gov (United States)

    Kamińska, Izabela; Elbaum, Danek; Sikora, Bożena; Kowalik, Przemysław; Mikulski, Jakub; Felcyn, Zofia; Samol, Piotr; Wojciechowski, Tomasz; Minikayev, Roman; Paszkowicz, Wojciech; Zaleszczyk, Wojciech; Szewczyk, Maciej; Konopka, Anna; Gruzeł, Grzegorz; Pawlyta, Mirosława; Donten, Mikołaj; Ciszak, Kamil; Zajdel, Karolina; Frontczak-Baniewicz, Małgorzata; Stępień, Piotr; Łapiński, Mariusz; Wilczyński, Grzegorz; Fronc, Krzysztof

    2018-01-12

    Nanostructures as color-tunable luminescent markers have become major, promising tools for bioimaging and biosensing. In this paper separated molybdate/Gd 2 O 3 doped rare earth ions (erbium, Er 3+ and ytterbium, Yb 3+ ) core-shell nanoparticles (NPs), were fabricated by a one-step homogeneous precipitation process. Emission properties were studied by cathodo- and photoluminescence. Scanning electron and transmission electron microscopes were used to visualize and determine the size and shape of the NPs. Spherical NPs were obtained. Their core-shell structures were confirmed by x-ray diffraction and energy-dispersive x-ray spectroscopy measurements. We postulated that the molybdate rich core is formed due to high segregation coefficient of the Mo ion during the precipitation. The calcination process resulted in crystallization of δ/ξ (core/shell) NP doped Er and Yb ions, where δ-gadolinium molybdates and ξ-molybdates or gadolinium oxide. We confirmed two different upconversion mechanisms. In the presence of molybdenum ions, in the core of the NPs, Yb 3+ -[Formula: see text] (∣ 2 F 7/2 , 3 T 2 〉) dimers were formed. As a result of a two 980 nm photon absorption by the dimer, we observed enhanced green luminescence in the upconversion process. However, for the shell formed by the Gd 2 O 3 :Er, Yb NPs (without the Mo ions), the typical energy transfer upconversion takes place, which results in red luminescence. We demonstrated that the NPs were transported into cytosol of the HeLa and astrocytes cells by endocytosis. The core-shell NPs are sensitive sensors for the environment prevailing inside (shorter luminescence decay) and outside (longer luminescence decay) of the tested cells. The toxicity of the NPs was examined using MTT assay.

  17. Preparation and studies of Eu{sup 3+} and Tb{sup 3+} co-doped Gd{sub 2}O{sub 3} and Y{sub 2}O{sub 3} sol-gel scintillating films

    Energy Technology Data Exchange (ETDEWEB)

    Morales Ramirez, A. de J, E-mail: amoralesra@ipn.m [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada (CICATA) Unidad Altamira Instituto Politecnico Nacional Km. 14.5 Carr. Tampico-Puerto Industrial, C.P. 89600, Altamira, Tamaulipas (Mexico); Depto. de Ingenieria Metalurgica, ESIQIE-Instituto Politecnico Nacional UPALM C.P. 07738, Mexico D.F. (Mexico); Garcia Murillo, A.; Carrillo Romo, F. de J [Depto. de Ingenieria Metalurgica, ESIQIE-Instituto Politecnico Nacional UPALM C.P. 07738, Mexico D.F. (Mexico); Ramirez Salgado, J. [Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Lazaro Cardenas No. 152, CP 07730, Mexico D.F. (Mexico); Le Luyer, C. [LPCML, CNRS-UMR 5620/Universite Claude Bernard Lyon 1/69622 Villeurbanne Cedex (France); Chadeyron, G.; Boyer, D. [Laboratoire des Materiaux Inorganiques, CNRS-UMR 6002, Universite Blaise Pascal, 24 Ave des Landais F 63177 Aubiere Cedex (France); Moreno Palmerin, J. [Depto. de Ingenieria Metalurgica, ESIQIE-Instituto Politecnico Nacional UPALM C.P. 07738, Mexico D.F. (Mexico)

    2009-10-30

    Eu{sup 3+} (2.5 at.%) and Tb{sup 3+} (0.005-0.01 at.%) co-doped gadolinium and yttrium oxide (Gd{sub 2}O{sub 3} and Y{sub 2}O{sub 3}) powders and films have been prepared using the sol-gel process. High density and optical quality thin films were prepared with the dip-coating technique. Gadolinium (III) 2,4-pentadionate and yttrium (III) 2,4-pentadionate were used as precursors, and europium and terbium in their nitrate forms were used as doping agents. Chemical and structural analyses (infrared spectroscopy, X-ray diffraction and high-resolution transmission electron microscopy) were conducted on both sol-gel precursor powders and dip-coated films. The morphology of thin films heat-treated at 700 {sup o}C was studied by means of atomic force microscopy. It was shown that the highly dense and very smooth films had a root mean roughness (RMS) of 2 nm {+-} 0.2 (A = 0.0075 Tb{sup 3+}) and 24 nm {+-} 3.0 (B = 0.01 Tb{sup 3+}). After treatment at 700 {sup o}C, the crystallized films were in the cubic phase and presented a polycrystalline structure made up of randomly oriented crystallites with grain sizes varying from 20 to 60 nm. The X-ray induced emission spectra of Eu{sup 3+}- and Tb{sup 3+}-doped Gd{sub 2}O{sub 3} and Y{sub 2}O{sub 3} powders showed that Tb{sup 3+} contents of 0.005, 0.0075 and 0.01 at.% affected their optical properties. Lower Tb{sup 3+} concentrations (down to 0.005 at.%) in both systems enhanced the light yield.

  18. Ion-irradiation resistance of the orthorhombic Ln2TiO5 (Ln = La, Pr, Nd, Sm, Eu, Gd, Tb and Dy) series

    International Nuclear Information System (INIS)

    Aughterson, Robert D.; Lumpkin, Gregory R.; Ionescu, Mihail; Reyes, Massey de los; Gault, Baptiste; Whittle, Karl R.; Smith, Katherine L.; Cairney, Julie M.

    2015-01-01

    The response of Ln 2 TiO 5 (where Ln is a lanthanide) compounds exposed to high-energy ions was used to test their suitability for nuclear-based applications, under two different but complementary conditions. Eight samples with nominal stoichiometry Ln 2 TiO 5 (Ln = La, Pr, Nd, Sm, Eu, Gd, Tb and Dy), of orthorhombic (Pnma) structure were irradiated, at various temperatures, with 1 MeV Kr 2+ ions in-situ within a transmission electron microscope. In each case, the fluence was increased until a phase transition from crystalline to amorphous was observed, termed critical dose D c . At certain elevated temperatures, the crystallinity was maintained irrespective of fluence. The critical temperature for maintaining crystallinity, T c , varied non-uniformly across the series. The T c was consistently high for La, Pr, Nd and Sm 2 TiO 5 before sequential improvement from Eu to Dy 2 TiO 5 with T c 's dropping from 974 K to 712 K. In addition, bulk Dy 2 TiO 5 was irradiated with 12 MeV Au + ions at 300 K, 723 K and 823 K and monitored via grazing-incidence X-ray diffraction (GIXRD). At 300 K, only amorphisation is observed, with no transition to other structures, whilst at higher temperatures, specimens retained their original structure. The improved radiation tolerance of compounds containing smaller lanthanides has previously been attributed to their ability to form radiation-induced phase transitions. No such transitions were observed here. - Highlights: • First ion-irradiation studies on a number of novel compounds including Pr 2 TiO 5 , Eu 2 TiO 5 and Tb 2 TiO 5 . • Systematic in-situ ion-irradiation study of almost complete Ln 2 TiO 5 series (Ln = lanthanides) with orthorhombic crystal structure type. • The first grazing incidence study of bulk irradiated Dy 2 TiO 5 looking for irradiation induced phase transition.

  19. Study of hyperfine interactions in intermetallic compounds Gd(Ni,Pd,Cu)In, Tb(Ni,Pd)In, Dy(Ni,Pd)In and Ho(Ni,Pd)In; Estudo de interacoes hiperfinas em compostos intermetalicos Gd(Ni,Pd,Cu)In, Tb(Ni,Pd)In, Dy(Ni,Pd)In e Ho(Ni,Pd)In

    Energy Technology Data Exchange (ETDEWEB)

    Lapolli, Andre Luis

    2006-07-01

    Systematic behavior of magnetic hyperfine field (B{sub hf}) in the intermetallic compounds Gd(Ni,Pd,Cu)In Tb(Ni,Pd)In, Dy(Ni,Pd)In and Ho(Ni,Pd)In was studied by Perturbed Gamma-Gamma Angular Correlation spectroscopy. The measurements of B{sub hf} were carried out at the rare earth atom and in sites using the nuclear probes {sup 140}Ce and {sup 11}'1Cd respectively. The variation of hyperfine field with temperature, in most cases, follows the Brillouin function predicted from the molecular field theory. The hyperfine field values at rare earth atom sites obtained from {sup 140}Ce probe as well as at in sites obtained from {sup 111}Cd probe for each series of compounds were extrapolated to zero Kelvin B{sub hf}(T=0) from these curves. These values were compared with the values of the literature for other compounds containing the same rare earth element and all of them show a linear relationship with the ordering temperature. This indicates that the main contribution to B{sub hf} comes from the conduction electron polarization (CEP) through Fermi contact interaction and the principal mechanism of magnetic interaction in these compounds can be described by the RKKY type interaction. The values of B{sub hf}(T=0) for each family of intermetallic compounds RNiIn and RPdIn when plotted as a function of 4f spin projection of rare earth element also shows a linear relationship. Exceptions are the results for the compounds RNiIn obtained with {sup 111}Cd probe where a small deviation from linearity is observed. The results of the measurements carried out with the {sup 111}Cd probe were also analyzed to obtain the hyperfine parameters of the quadrupole interaction as a function of temperature for RPdln and GdNiIn compounds. The results show that for the compound GdPdIn there might be some Gd-In disorder at high temperature. (author)

  20. Core/shell structured NaYF4:Yb3+/Er3+/Gd+3 nanorods with Au nanoparticles or shells for flexible amorphous silicon solar cells

    International Nuclear Information System (INIS)

    Li, Z Q; Li, X D; Liu, Q Q; Chen, X H; Sun, Z; Huang, S M; Liu, C; Ye, X J

    2012-01-01

    A simple approach for preparing near-infrared (NIR) to visible upconversion (UC) NaYF 4 :Yb/Er/Gd nanorods in combination with gold nanostructures has been reported. The grown UC nanomaterials with Au nanostructures have been applied to flexible amorphous silicon solar cells on the steel substrates to investigate their responses to sub-bandgap infrared irradiation. Photocurrent–voltage measurements were performed on the solar cells. It was demonstrated that UC of NIR light led to a 16-fold to 72-fold improvement of the short-circuit current under 980 nm illumination compared to a cell without upconverters. A maximum current of 1.16 mA was obtained for the cell using UC nanorods coated with Au nanoparticles under 980 nm laser illumination. This result corresponds to an external quantum efficiency of 0.14% of the solar cell. Mechanisms of erbium luminescence in the grown UC nanorods were analyzed and discussed. (paper)

  1. Heat capacities, magnetic properties, and resistivities of ternary RPdBi alloys where R = La, Nd, Gd, Dy, Er, and Lu

    International Nuclear Information System (INIS)

    Riedemann, T.M.

    1996-01-01

    Over the past four and a half decades research on the rare earths, their compounds, and their alloys has yielded significant insights into the nature of materials. The rare earths can be used to systematically study a series of alloys or compounds. Magnetic ordering, crystalline fields, spin fluctuations, the magnetocaloric effect, and magnetostriction are a small sample of phenomena studied that are exhibited by the rare earth family. A significant portion of research has been conducted on the abundant RM 2 and RM phases, where R is the rare earth and M is a transition metal. The natural progression of science has led to the study of related RMX ternary phases, where X is either another transition metal or semimetal. There are now over 1,000 known RMX phases. The focus of this study is on RPdBi where R = La, Nd, Gd, Dy, Er, and Lu. Their heat capacities, magnetic properties, and resistivities are studied

  2. Benefits of Silica Core-Shell Structures on the Temperature Sensing Properties of Er,Yb:GdVO4 Up-Conversion Nanoparticles.

    Science.gov (United States)

    Savchuk, Oleksandr A; Carvajal, Joan J; Cascales, C; Aguiló, M; Díaz, F

    2016-03-23

    We studied the temperature-dependent luminescence of GdVO4 nanoparticles co-doped with Er(3+) (1 mol %) and Yb(3+) (20 mol %) and determined their thermal sensing properties through the fluorescence intensity ratio (FIR) technique. We also analyzed how a silica coating, in a core-shell structure, affects the temperature sensing properties of this material. Spectra were recorded in the range of biological temperatures (298-343 K). The absolute sensitivity for temperature determination calculated for the core-shell nanoparticles is double the one calculated for bare nanoparticles, achieving a thermal resolution of 0.4 K. Moreover, silica-coated nanoparticles show good dispersibility in different solvents, such as water, DMSO, and methanol. Also, they show good luminescence stability without interactions with solvent molecules. Furthermore, we also observed that the silica coating shell prevents progressive heating of the nanoparticles during prolonged excitation periods with the 980 nm laser, preventing effects on their thermometric applications.

  3. Crystal Chemistry and Photocatalytic Properties of RE4S4Te3 (RE = Gd, Ho, Er, Tm): Experimental and Theoretical Investigations.

    Science.gov (United States)

    Chi, Yang; Rong, Liang-Zhen; Suen, Nian-Tzu; Xue, Huai-Guo; Guo, Sheng-Ping

    2018-04-25

    Reported are the synthesis and structural characterization of a new series of ternary rare-earth mix-chalcogenides RE 4 S 4 Te 3 (RE = Gd, Ho, Er, Tm) that have been obtained from high-temperature solid state reactions. These compounds crystallize in Ho 4 S 4 Te 2.68 structure types with monoclinic C2/ m and/or orthorhombic Immm space groups. The space group variation within this series is due to the position disorder along the Te plane (Te to TeA and TeB). The structural relationship and change between these two space groups are analyzed. It is realized that these compounds are all photocatalytic active under simulated sunlight. The trend of their photocatalytic activities and photocurrent responses is well-explained by using theoretical calculation as well as dipole moment analysis.

  4. Seed-mediated synthesis of NaY F4:Y b, Er/NaGdF4 nanocrystals with improved upconversion fluorescence and MR relaxivity

    International Nuclear Information System (INIS)

    Guo Hai; Li Zhengquan; Qian Haisheng; Hu Yong; Muhammad, Idris Niagara

    2010-01-01

    Rational combination of different functional lanthanide materials within a single nanocrystal presents a feasible way to develop a multifunctional nanoplatform for various biomedical applications. The conventional methods of synthesizing and integrating two kinds of material together generally involve laborious procedures, whilst codoping different functional ions inside a single lanthanide nanocrystal usually results in a decrease in both its fluorescence and its magnetic resonance relaxivity. Here, we present a seed-mediated synthetic route to prepare core-shell structured NaY F 4 :Y b, Er/NaGdF 4 nanocrystals. Epitaxial growth of a gadolinium layer on an upconversion lanthanide seed not only improves its upconversion fluorescence, but also creates a paramagnetic shell with high magnetic resonance relaxivity. The prepared nanocrystals are uniform in size, stable in water and easy for conjugation after modification, which may have the potential to serve as a versatile imaging tool for smart detection or diagnosis in future biomedical engineering.

  5. The risk assessment of Gd{sub 2}O{sub 3}:Yb{sup 3+}/Er{sup 3+} nanocomposites as dual-modal nanoprobes for magnetic and fluorescence imaging

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Long [Sun Yat-sen University, Department of Histology and Embryology, Zhongshan School of Medicine (China); Tian, Xiumei [Guangzhou Medical University, Department of Biomedical Engineering (China); Liu, Jun [Guangdong Ocean University, School of Electronics and Information Technology (China); Zheng, Cunjing; Xie, Fukang, E-mail: frankxie2000@yahoo.com [Sun Yat-sen University, Department of Histology and Embryology, Zhongshan School of Medicine (China); Li, Li, E-mail: li2@mail.sysu.edu.cn [Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Imaging Diagnosis and Interventional Center (China)

    2017-02-15

    Our group has synthesized Gd{sub 2}O{sub 3}:Yb{sup 3+}/Er{sup 3+} nanocomposites as magnetic/fluorescence imaging successfully in the previous study, which exhibit good uniformity and monodispersibility with a mean size of 7.4 nm. However, their systematic risk assessment remains unknown. In this article, the in vitro biocompatibility of the Gd{sub 2}O{sub 3}:Yb{sup 3+}/Er{sup 3+} was assessed on the basis of cell viability and apoptosis. In vivo immunotoxicity was evaluated by monitoring the product of reactive oxygen species (ROS), clusters of differentiation (CD) markers, and superoxide dismutase (SOD) in Balb/c mice. No significant differences were found in cell viability, apoptosis, and immunotoxicity between our Gd{sub 2}O{sub 3}:Yb{sup 3+}/Er{sup 3+} and gadodiamide which are used commonly in clinical. Few nanoprobes were localized in the phagosomes of the liver, heart, lung, spleen, kidney, brain, and tumor under the transmission electron microscopy (TEM) images. In addition, our products reveal good T{sub 1}-weighted contrast enhancement of xenografted murine tumor. Therefore, the above results may contribute to the effective application of Gd{sub 2}O{sub 3}:Yb{sup 3+}/Er{sup 3+} as molecular imaging contrast agents and dual-modal nanoprobes for cancer detection.

  6. Hydrothermal synthesis and photoluminescent properties of hierarchical GdPO4·H2O:Ln3+ (Ln3+ = Eu3+, Ce3+, Tb3+) flower-like clusters

    Science.gov (United States)

    Amurisana, Bao.; Zhiqiang, Song.; Haschaolu, O.; Yi, Chen; Tegus, O.

    2018-02-01

    3D hierarchical GdPO4·H2O:Ln3+ (Ln3+ = Eu3+, Ce3+, Tb3+) flower clusters were successfully prepared on glass slide substrate by a simple, economical hydrothermal process with the assistance of disodium ethylenediaminetetraacetic acid (Na2H2L, where L4- = (CH2COO)2N(CH2)2N(CH2COO)24-). In this process, Na2H2L was used as both a chelating agent and a structure-director. The hierarchical flower clusters have an average diameter of 7-12 μm and are composed of well-aligned microrods. The influence of the molar ratio of Na2H2L/Gd3+ and reaction time on the morphology was systematically studied. A possible crystal growth and formation mechanism of hierarchical flower clusters is proposed based on the evolution of morphology as a function of reaction time. The self-assembled GdPO4·H2O:Ln3+ superstructures exhibit strong orange-red (Eu3+, 5D0 → 7F1), green (Tb3+, 5D4 → 7F5) and near ultraviolet emissions (Ce3+, 5d → 7F5/2) under ultraviolet excitation, respectively. This study may provide a new channel for building hierarchically superstructued oxide micro/nanomaterials with optical and new properties.

  7. Slow magnetic relaxation and single-molecule toroidal behaviour in a family of heptanuclear {Cr"I"I"ILn"I"I"I_6} (Ln=Tb, Ho, Er) complexes

    Energy Technology Data Exchange (ETDEWEB)

    Vignesh, Kuduva R. [IITB-Monash Research Academy, IIT Bombay, Powai, Mumbai (India); Langley, Stuart K. [School of Science and the Environment, Division of Chemistry, Manchester Metropolitan University, Manchester (United Kingdom); Swain, Abinash; Rajaraman, Gopalan [Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai (India); Moubaraki, Boujemaa; Murray, Keith S. [School of Chemistry, Monash University, Clayton, VIC (Australia); Damjanovic, Marko; Wernsdorfer, Wolfgang [Institute Neel, CNRS, Universite Grenoble Alpes, Grenoble (France); Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen (Germany)

    2018-01-15

    The synthesis, magnetic properties, and theoretical studies of three heterometallic {Cr"I"I"ILn"I"I"I_6} (Ln=Tb, Ho, Er) complexes, each containing a metal topology consisting of two Ln{sub 3} triangles connected via a Cr{sup III} linker, are reported. The {CrTb_6} and {CrEr_6} analogues display slow relaxation of magnetization in a 3000 Oe static magnetic field. Single-crystal measurements reveal opening up of the hysteresis loop for {CrTb_6} and {CrHo_6} molecules at low temperatures. Ab initio calculations predict toroidal magnetic moments in the two Ln{sub 3} triangles, which are found to couple, stabilizing a con-rotating ferrotoroidal ground state in Tb and Ho examples and extend the possibility of observing toroidal behaviour in non Dy{sup III} complexes for the first time. (copyright 2018 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Preparation, Characterization, and Ionic Transport Properties of Nanoscale Ln2Zr2O7 (Ln = Ce, Pr, Nd, Sm, Gd, Dy, Er, and Yb) Energy Materials

    Science.gov (United States)

    Solomon, Sam; George, Aneesh; Thomas, Jijimon Kumpakkattu; John, Annamma

    2015-01-01

    Nanoparticles of lanthanide (Ln)-based zirconates have been prepared through the autoignited combustion technique. The structure of the system was analyzed by powder x-ray diffraction and vibrational spectroscopic tools. The compounds with Ln = Ce, Pr, Nd, Sm, and Gd have pyrochlore cubic structure, whereas those with Ln = Dy, Er, and Yb possess anion-deficient disordered cubic fluorite structure. The optical properties of the powder were analyzed using ultraviolet-visible spectroscopy. Pellets of the compounds were sintered in the range from 1325°C to 1530°C for 2 h. The surface morphology of sintered Nd2Zr2O7 was analyzed by scanning electron microscopy. Impedance spectroscopic studies of the samples were carried out at different temperatures. The conductivity increased to the order of 10-2 S/m at 750°C, and the highest conductivity of 13.21 × 10-2 S/m was obtained for Er2Zr2O7. All samples of this system are suitable candidates for fabrication of electrolytes for use in solid oxide fuel cells, particularly at moderate temperatures.

  9. Complexes of o-Vanillin oxime with La(III), Ce(III), Nd(III), Sm(III), Gd(III), Tb(III), Dy(III), Ho(III) and Yb(III)

    International Nuclear Information System (INIS)

    Dhar, M.L.; Gupta, V.K.; Singh, Onkar

    1988-01-01

    Ten complexes of lanthanides with o-vanillin oxime have been swynthesised and characterised. The composition of the complexes as determined by elemental and thermal analyses, infrared electronic spectral and magnetic moment studies is [Ln(C 8 H 8 NO 3 ) 3 .XH 2 O], where X=2 when Ln=La, Ce, Pr, Nd, Sm and X=3 when Ln=Gd, Dy, Tb, Ho, Yb; C 8 H 8 NO 3 - represents the anion of the ligand. (author). 16 refs., 2 figs., 2 tables

  10. Syntheses, structures, and properties of a series of novel high-nuclear 3d-4f clusters with mixed amino acids as ligands: {Ln6Cu24}(Ln = Gd, Tb, Pr and Sm).

    Science.gov (United States)

    Shen, Chao-Jun; Hu, Sheng-Min; Sheng, Tian-Lu; Xue, Zhen-Zhen; Wu, Xin-Tao

    2015-04-14

    The first examples of high-nuclear 3d-4f heterometallic clusters with mixed amino acid ligands are reported. Four 30-nuclear clusters {Ln6Cu24}(Ln = Gd, Tb, Pr and Sm) were obtained through the self-assembly of Ln(III), Cu(II) and mixed amino acid ligands of glycine (HGly) and β-alanine (HAla). The metal skeleton of clusters may be described as a huge {Ln6Cu12} octahedron connected with 12 additional Cu(II) ions. The temperature dependence of magnetic susceptibilities of compounds were also studied.

  11. A facile synthesis approach and impact of shell formation on morphological structure and luminescent properties of aqueous dispersible NaGdF{sub 4}:Yb/Er upconversion nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Ansari, Anees A., E-mail: aneesaansari@gmail.com [King Saud University, King Abdullah Institute for Nanotechnology (Saudi Arabia); Yadav, Ranvijay; Rai, S. B. [Banaras Hindu University, Department of Physics (India)

    2016-12-15

    A general facile synthesis approach was used for fabrication of highly emissive aqueous dispersible hexagonal phase upconversion luminescent NaGdF{sub 4}:Yb/Er nanorods (core NRs) through metal complex decomposition process. An inert NaGdF{sub 4} and porous silica layers were grafted surrounding the surface of each and every NRs to enhance their luminescence efficiency and colloidal dispersibility in aqueous environment. Optical properties in terms of band gap energy of core, core/shell, and silica-coated core/shell/SiO{sub 2} nanorods were observed to investigate the influence of surface coating, which was gradually decreased after surface coating because of increase crystalline size after growth of inert and silica shells. The inert shell formation before silica surface grafting, upconversion luminescence intensity was greatly improved by about 20 times, owing to the effective surface passivation of the seed core and, therefore, protection of Er{sup 3+} ion in the core from the nonradiative decay caused by surface defects. Moreover, after silica coating, core/shell nanorods shows strong upconversion luminescence property similar to the hexagonal upconversion core NRs. It is expected that these NaGdF{sub 4}:Yb/Er@NaGdF{sub 4}@SiO{sub 2} (core/shell/SiO{sub 2}) NRs including highly upconversion emissive and aqueous dispersible properties make them an ideal materials for various photonic-based potential applications such as in upconversion luminescent bioimaging, magnetic resonance imaging, and photodynamic therapy.

  12. Spectroscopic Properties and Laser Performance of Resonantly-Pumped Cryo-Cooled Er3+:GdVO4

    Science.gov (United States)

    2012-03-12

    Romanowski , 2 T. Lukasiewicz, 3 and M. Dubinskii 1 1 US Army Research Laboratory, 2800 Powder Mill Rd., Adelphi, MD 20783, USA 2Institute of Low...Ryba- Romanowski , and M. Dubinskii, “High power resonantly diode-pumped σ-configuration Er3+:YVO4 laser at 1593.5 nm,” Laser Phys. Lett. 8(7), 529...534 (2011). 5. N. Ter-Gabrielyan, V. Fromzel, T. Lukasiewicz, W. Ryba- Romanowski , and M. Dubinskii, “Nearly quantum- defect-limited efficiency

  13. Symmetry-Breaking Transitions in RECuAs2-xPx (RE=Sm, Gd, Ho, and Er)

    Energy Technology Data Exchange (ETDEWEB)

    Mozharivskyj, Yurij [Iowa State Univ., Ames, IA (United States)

    2002-01-01

    Structural changes resulting in lower symmetries can be understood in terms of electronic instabilities and Coulomb interactions. The interplay of these two interrelated factors is complicated and difficult to analyze. The RECuAs2-xP x phases, because of the variation in the chemical content (As/P substitution), allow, with the aid of band structures, Madelung energies and Landau theory, a partial unraveling of the forces important in the symmetry-breaking transitions in RECuAs2-xP x (RE = Sm, Gd, Ho and Er). Distortions of the P layers in SmCu1.15P2, GdCuP2.20 and ErCuP2 are usefully thought of as generalized Peierls distortions, i.e., they lower the electronic (and total) energy and lead to more stable structures. On the other hand, the P4/nmm → Pmmn transitions, which are observed in all studied arsenophosphide series and occur upon substitution of P for As, originate from the B1g vibrational mode and are structural adaptations to smaller P atoms. These transitions provide tighter atomic packing and better Coulomb interactions. Configurational contribution to the entropy becomes important in stabilizing the mixed occupancy in the RECuAs 2-xP x arsenophosphides. While geometric and electronic factors favor separation of the As and P atoms over two different crystallographic sites, configurational entropy stabilizes the As/P mixing on these two sites.;Progress in the research on RECuAs2-xP x was dependent upon the ability of Landau theory to predict, explain and dismiss structural models and transitions. The space group Pmmn (arising from the B 1g vibrational mode) in all mixed arsenophosphides and the existence of these mixed arsenophosphides followed from the analysis of GdCuAs 2 and GdCuP2, using Landau theory. The impossibility of obtaining the high-symmetry structure (P4/nmm) and the low symmetry structure

  14. Ultrasmall, water dispersible, TWEEN80 modified Yb:Er:NaGd(WO4)2 nanoparticles with record upconversion ratiometric thermal sensitivity and their internalization by mesenchymal stem cells

    Science.gov (United States)

    Cascales, Concepción; Paíno, Carlos L.; Bazán, Eulalia; Zaldo, Carlos

    2017-05-01

    This work presents the synthesis by coprecipitation of diamond shaped Yb:Er:NaGd(WO4)2 crystalline nanoparticles (NPs) with diagonal dimensions in the 5-7 nm × 10-12 nm range which have been modified with TWEEN80 for their dispersion in water, and their interaction with mesenchymal stem cells (MSCs) proposed as cellular NP vehicles. These NPs belong to a large family of tetragonal Yb:Er:NaT(XO4)2 (T = Y, La, Gd, Lu; X = Mo, W) compounds with green (2H11/2 + 4S3/2 → 4I15/2) Er-related upconversion (UC) efficiency comparable to that of Yb:Er:β-NaYF4 reference compound, but with a ratiometric thermal sensitivity (S) 2.5-3.5 times larger than that of the fluoride. At the temperature range of interest for biomedical applications (˜293-317 K/20-44 °C) S = 108-118 × 10-4 K-1 for 20 at%Yb:5 at%Er:NaGd(WO4)2 NPs, being the largest values so far reported using the 2H11/2/4S3/2 Er intensity ratiometric method. Cultured MSCs, incubated with these water NP emulsions, internalize and accumulate the NPs enclosed in endosomes/lysosomes. Incubations with up to 10 μg of NPs per ml of culture medium maintain cellular metabolism at 72 h. A thermal assisted excitation path is discussed as responsible for the UC behavior of Yb:Er:NaT(XO4)2 compounds.

  15. Judd–Ofelt analysis and transition probabilities of Er{sup 3+} doped KY{sub 1−x−y}Gd{sub x}Lu{sub y}(WO{sub 4}){sub 2} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Martínez de Mendívil, Jon, E-mail: jon.martinez@uam.es [Departamento de Física de Materiales, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Lifante, Ginés [Departamento de Física de Materiales, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Pujol, Maria Cinta; Aguiló, Magdalena; Díaz, Francesc [Física i Cristalografia de Materials i Nanomaterials (FiCMA-FiCNA), Universitat Rovira i Virgili, Tarragona (Spain); Cantelar, Eugenio [Departamento de Física de Materiales, Universidad Autónoma de Madrid, 28049 Madrid (Spain)

    2015-09-15

    In this work the transition probabilities, radiative lifetimes and branching ratios of Er{sup 3+} ions in KY{sub 1−x−y}Gd{sub x}Lu{sub y}(WO{sub 4}){sub 2} crystals have been determined. With this aim, Er{sup 3+} doped KY{sub 1−x−y}Gd{sub x}Lu{sub y}(WO{sub 4}){sub 2} crystals have been grown by means of the high temperature Top-Seeded Solution Growth. A spectroscopic analysis of Er{sup 3+} ions in this crystal has been performed following anisotropic Judd–Ofelt analysis to obtain basic spectroscopic properties. A quantum efficiency over 97% has been determined for the {sup 4}I{sub 13/2}→{sup 4}I{sub 15/2} transition, indicating that this material is adequate for the development of lasers and amplifiers working in the third telecommunication window. - Highlights: • Er{sub 0.01}:KY{sub 1−x−y}Gd{sub x}Lu{sub y}(WO{sub 4}){sub 2} crystals have been grown. • Anisotropic Judd Ofelt analysis has been carried out. • Optical transition probabilities and branching ratios have been calculated. • Radiative and non-radiative lifetimes have been obtained.

  16. Fabrication and evaluation of a Gd{sub 2}O{sub 2}S:Tb phosphor screen film for development of a CMOS-based X-ray imaging detector

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ji Koon; Choi, Su Rim; Noh, Si Cheol; Jung, Bong Jae; Choi, Il Hong; Kang, Sang Sik [International University of Korea, Jinju (Korea, Republic of)

    2014-08-15

    In this study, Gd{sub 2}O{sub 2}S:Tb phosphor screen films were fabricated by using a special particle-inbinder sedimentation method. The phosphor particles used in this study were manufactured in two sizes, 2.5-μm and 5-μm. To evaluate luminescence efficiency and the spatial resolution according to the thickness, we fabricated screen films with thicknesses of 120, 150, 170, and 210-μm. The spatial resolution of the fabricated films was assessed by using an edge method to measure the modulation transfer function (MTF). From the experimental results, the spatial resolution of the mammography exposures (low-energy X-ray quality) was better than that of dental radiography (high-energy X-ray quality). Also, with the same film thickness, the screen with 2.5-μm particles had better resolution than the screen with 5.0-μm particles, but it showed about 20% lower resolution than a commercial Gd{sub 2}O{sub 2}S:Tb screen. In the evaluation of the results for the dependence of the spatial resolution on the film's thickness, the 120-μm-thick screen showed the highest resolution, which was similar to that of a commercial screen.

  17. Investigation on the magnetocaloric effect in DyNi{sub 2}, DyAl{sub 2} and Tb{sub 1-n}Gd{sub n}Al{sub 2} (n=0, 0.4, 0.6) compounds

    Energy Technology Data Exchange (ETDEWEB)

    Sousa, V.S.R. de [Instituto de Fisica Armando Dias Tavares, Universidade do Estado do Rio de Janeiro, Rua Sao Francisco Xavier 524, 20550-900 Rio de Janeiro (Brazil)], E-mail: vinidesousa@gmail.com; Plaza, E.J.R. [Instituto de Fisica Armando Dias Tavares, Universidade do Estado do Rio de Janeiro, Rua Sao Francisco Xavier 524, 20550-900 Rio de Janeiro (Brazil); Reis, M.S. [CICECO, Universidade de Aveiro, 3810-193 Aveiro (Portugal); Alho, B.P. [Instituto de Fisica Armando Dias Tavares, Universidade do Estado do Rio de Janeiro, Rua Sao Francisco Xavier 524, 20550-900 Rio de Janeiro (Brazil); Carvalho, A. Magnus G. [Divisao de Metrologia de Materiais, Inmetro, Duque de Caxias (Brazil); Gama, S. [Departamento de Ciencias Exatas e da Terra, Unifesp, Diadema (Brazil); Oliveira, N.A. de; Ranke, P.J. von [Instituto de Fisica Armando Dias Tavares, Universidade do Estado do Rio de Janeiro, Rua Sao Francisco Xavier 524, 20550-900 Rio de Janeiro (Brazil)

    2009-10-15

    The magnetocaloric effect (MCE) in the DyNi{sub 2}, DyAl{sub 2} and Tb{sub 1-n}Gd{sub n}Al{sub 2} (n=0, 0.4, 0.6) was theoretically investigated in this work. The DyNi{sub 2} and DyAl{sub 2} compounds are described considering a model Hamiltonian which includes the crystalline electrical field anisotropy. The anisotropic MCE was calculated changing the magnetic field direction from <1 1 1> to <0 0 1> in DyNi{sub 2} and from <1 0 0> to <0 1 1> in DyAl{sub 2}. The influence of the second- and first-order spin-reorientation phase transitions on the MCE that occurs in these systems is discussed. For the calculations of the MCE thermodynamic quantities in the Tb{sub 1-n}Gd{sub n}Al{sub 2} systems we take into account a two sites magnetic model, and good agreement with the available experimental data was obtained.

  18. Effect of Er, Gd, and Nd Co-Dopants on the Properties of Sm-Doped Ceria Electrolyte for IT-SOFC

    Science.gov (United States)

    Arabacı, Aliye

    2017-05-01

    Doped ceria electrolytes of Ce0.8Sm0.20O1.90 (SDC), Ce0.8Er0.08Sm0.12O1.90 (ESDC), Ce0.8Gd0.08Sm0.12O1.90 (GSDC), and Ce0.8Nd0.08Sm0.12O1.90 (NSDC) were prepared by a citric-nitrate combustion process. The thermal decomposition of the precursor was investigated by simultaneous thermogravimetric analysis and differential thermal analysis experiments. The phase structure of the calcined and sintered powders was characterized by X-ray diffraction analysis. All of the samples were fluorite-type ceria-based solid solutions. The calcined and sintered powders were also characterized by Fourier transform infrared spectroscopy. Scanning electron microscopy was used to characterize the samples after calcination and sintering. A relative density over 95 percent of the theoretical density was achieved after the sintering process. Electrical conductivities of the sintered samples were measured using the impedance spectra method. The highest ionic conductivity value was found to be 5.28 × 10-2 S cm-1 at 1023 K (750 °C) for GSDC sintered at 1673 K (1400 °C) for 6 hours.

  19. Study of amorphous semiconductors doped with rare earths (Gd and Er) and conducting polymers by EPR techniques and magnetic susceptibility

    International Nuclear Information System (INIS)

    Sercheli, Mauricio da Silva

    1999-01-01

    This thesis involves the study of amorphous semiconductors and conducting polymers, which have been characterized by EPR and magnetic susceptibility measurements, and to a lesser extent by Raman spectroscopy and RBS. The semiconductors were studied using thin films of silicon doped with rare earth metals, e.g. erbium and gadolinium, which had their magnetic properties studied. Using these studies we could determine the state of valence of the rare earths as well as their concentrations in the silicon matrix. According to our results, the valence of the rare earth metal ions is 3+, and we were able to conclude that 4f electronic shells could not be used for the calculation of the conducting band in this system. Furthermore, the analysis of the data on the magnetic susceptibility of the Er 3+ ion with cubic crystalline acting field, gave us the opportunity to estimate the overall splitting of their electronic states for the first time. The conducting polymers were studied using samples of poly(3-methylthiophene) doped with ClO 4 - , which show a phase transition in the range of 230 K to 130 K. The electron paramagnetic resonance also gives important information on the crystallization, doping level and the presence of polarons or bipolarons in conducting polymers. (author)

  20. Use of the ion exchange method for the determination of stability constants of trivalent metal complexes with humic and fulvic acids II. Tb3+, Yb3+ and Gd3+ complexes in weakly alkaline conditions

    International Nuclear Information System (INIS)

    Dong Wenming; Li Weijuan; Tao Zuyi

    2002-01-01

    The conditional stability constants for tracer concentrations of Tb(III), Yb(III), and Gd(III) with three soil humic acids, three soil fulvic acids and a fulvic acid from weathered coal were determined at pH 9.0-9.1 (these values are similar to those in calcareous soils) in the presence of NaHCO 3 by using the anion exchange method. It was found that 1 : 1 and 1 : 2 complexes were simultaneously formed in the weakly alkaline conditions. The conditional stability constants of these 1 : 1 and 1 : 2 complexes were calculated from the distribution coefficients of rare earth elements at various concentrations of humate or fulvate. The stability constants indicate the very high stability of trivalent Tb 3+ , Yb 3+ and Gd 3+ complexes with humic substances in weakly alkaline conditions. The key parameters necessary for the experimental determination of the conditional stability constants of metal ions with humic substances in the presence of NaHCO 3 by using an anion exchange method were discussed. The conditional stability constants of these 1 : 1 and 1 : 2 complexes were compared in this paper. It was found that stabilities of Tb 3+ 1 : 1 and 1 : 2 complexes with humic acid are greater than the corresponding ones with fulvic acid from the same soil. In addition, the effect of the presence of Ca 2+ as a competitor on the stabilities of 1 : 1 and 1 : 2 complexes of Yb was examined and no pronounced change of stabilities of 1 : 1 complex was found, even though Ca 2+ is in a 10 3 excess to Yb 3+

  1. Flux Crystal Growth of the RE2Ru3Ge5 (RE = La, Ce, Nd, Gd, Tb) Series and Their Magnetic and Metamagnetic Transitions

    Energy Technology Data Exchange (ETDEWEB)

    Bugaris, Daniel E. [Materials Science; Malliakas, Christos D. [Materials Science; Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States; Bud’ko, Sergey L. [Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, United States; Division of Materials Science & amp, Engineering, Ames Laboratory, Ames, Iowa 50011, United States; Calta, Nicholas P. [Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States; Chung, Duck Young [Materials Science; Kanatzidis, Mercouri G. [Materials Science; Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States

    2017-11-16

    Previously synthesized only as powders, single crystals of the RE2Ru3Ge5 (RE = La, Ce, Nd, Gd, Tb) series of compounds have been now been obtained from molten In. These materials crystallize with the U2Co3Si5-type structure in orthorhombic space group Ibam with lattice parameters a ~ 10.00-9.77 Å (La-Tb), b ~ 12.51-12.35 Å, and c ~ 5.92-5.72 Å. The structure is a three-dimensional framework consisting of RuGe5 and RuGe6 units, as well as Ge-Ge zigzag chains. This structure type, along with the other five (Sc2Fe3Si5, Lu2Co3Si5, Y2Rh3Sn5, Yb2Ir3Ge5, and Yb2Pt3Sn5) to compose the RE2T3X5 phase space, are discussed in depth. For the three compounds with RE = Nd, Gd, and Tb, multiple magnetic transitions and metamagnetic behavior are observed. Electronic band structure calculations performed on La2Ru3Ge5 indicate that these materials have a negative band gap and are semimetallic in nature.

  2. Structural Characterization and Absolute Luminescence Efficiency Evaluation of Gd2O2S High Packing Density Ceramic Screens Doped with Tb3+ and Eu3+ for further Applications in Radiology

    Science.gov (United States)

    Dezi, Anna; Monachesi, Elenasophie; D'Ignazio, Michela; Scalise, Lorenzo; Montalto, Luigi; Paone, Nicola; Rinaldi, Daniele; Mengucci, Paolo; Loudos, George; Bakas, Athanasios; Michail, Christos; Valais, Ioannis; Fountzoula, Christine; Fountos, George; David, Stratos

    2017-11-01

    Rare earth activators are impurities added in the phosphor material to enhance probability of visible photon emission during the luminescence process. The main activators employed are rare earth trivalent ions such as Ce+3, Tb+3, Pr3+ and Eu+3. In this work, four terbium-activated Gd2O2S (GOS) powder screens with different thicknesses (1049 mg/cm2, 425.41 mg/cm2, 313 mg/cm2 and 187.36 mg/cm2) and one europium-activated GOS powder screen (232.18 mg/cm2) were studied to investigate possible applications for general radiology detectors. Results presented relevant differences in crystallinity between the GOS:Tb doped screens and GOS:Eu screens in respect to the dopant agent present. The AE (Absolute efficiency) was found to rise (i) with the increase of the X-ray tube voltage with the highest peaking at 110kVp and (ii) with the decrease of the thickness among the four GOS:Tb. Comparing similar thickness values, the europium-activated powder screen showed lower AE than the corresponding terbium-activated.

  3. Synthesis and characterization of heterobinuclear (La-Zn, Pr-Zn, Nd-Zn, Sm-Zn, Eu-Zn, Gd-Zn, Tb-Zn, Dy-Zn) azine-bridged complexes

    International Nuclear Information System (INIS)

    Singh, Bachcha; Srivastav, A.K.; Singh, P.K.

    1997-01-01

    Zinc(II) complex of 2-acetylpyridine salicyl aldazine (Haps) of the type Zn(aps) 2 (H 2 O) 2 has been synthesised. The reaction of Zn(aps) 2 (H 2 O) 2 with lanthanide chlorides, LnCl 3 (where Ln=La, Pr, Nd, Sm, Eu, Gd, Tb and Dy) yields azine-bridged heterobinuclear complexes of the formulae LnCl 3 Zn(aps) 2 (H 2 O) 2 . These complexes have been characterized by elemental analyses, molecular weight, conductance (solid and solution) and magnetic susceptibility measurements, mass, IR and electronic spectral data. X-ray powder diffraction data indicate the tetragonal unit lattice for Zn(aps) 2 (H 2 O) 2 and PrCl 3 Zn(aps) 2 (H 2 O) 2 . (author)

  4. Magnetic Interactions in the Double Perovskites R2NiMnO6 (R = Tb, Ho, Er, Tm) Investigated by Neutron Diffraction.

    Science.gov (United States)

    Retuerto, María; Muñoz, Ángel; Martínez-Lope, María Jesús; Alonso, José Antonio; Mompeán, Federico J; Fernández-Díaz, María Teresa; Sánchez-Benítez, Javier

    2015-11-16

    R2NiMnO6 (R = Tb, Ho, Er, Tm) perovskites have been prepared by soft-chemistry techniques followed by high oxygen-pressure treatments; they have been investigated by X-ray diffraction, neutron powder diffraction (NPD), and magnetic measurements. In all cases the crystal structure is defined in the monoclinic P21/n space group, with an almost complete order between Ni(2+) and Mn(4+) cations in the octahedral perovskite sublattice. The low temperature NPD data and the macroscopic magnetic measurements indicate that all the compounds are ferrimagnetic, with a net magnetic moment different from zero and a distinct alignment of Ni and Mn spins depending on the nature of the rare-earth cation. The magnetic structures are different from the one previously reported for La2NiMnO6, with a ferromagnetic structure involving Mn(4+) and Ni(2+) moments. This spin alignment can be rationalized taking into account the Goodenough-Kanamori rules. The magnetic ordering temperature (TCM) decreases abruptly as the size of the rare earth decreases, since TCM is mainly influenced by the superexchange interaction between Ni(2+) and Mn(4+) (Ni(2+)-O-Mn(4+) angle) and this angle decreases with the rare-earth size. The rare-earth magnetic moments participate in the magnetic structures immediately below TCM.

  5. Theoretical and experimental spectroscopic studies of the first highly luminescent binuclear hydrocinnamate of Eu(III), Tb(III) and Gd(III) with bidentate 2,2'-bipyridine ligand

    Energy Technology Data Exchange (ETDEWEB)

    Marques, Lippy F.; Correa, Charlane C.; Garcia, Humberto C. [Departamento de Química-ICE, Universidade Federal de Juiz de Fora, Juiz de Fora-MG 36036-330 (Brazil); Martins Francisco, Thiago [Departamento de Física-ICEx, Universidade Federal de Minas Gerais, Pampulha, Belo Horizonte-MG 30123-970 (Brazil); Ribeiro, Sidney J.L. [Instituto de Química, Universidade Estadual Paulista Júlio de Mesquita Filho-UNESP, CP 355, Araraquara-SP 14801-970 (Brazil); Dutra, José Diogo L.; Freire, Ricardo O. [Pople Computational Chemistry Laboratory, Departamento de Química, Universidade Federal de Sergipe, São Cristóvão-SE 49100-000 (Brazil); Machado, Flávia C., E-mail: flavia.machado@ufjf.edu.br [Departamento de Química-ICE, Universidade Federal de Juiz de Fora, Juiz de Fora-MG 36036-330 (Brazil)

    2014-04-15

    In this paper, the synthesis of three new binuclear lanthanide (III) complexes [Ln{sub 2}(cin){sub 6}(bpy){sub 2}] (Ln=Eu (1), Tb (2), Gd (3), cin=hydrocinnamate anion; bpy=2,2'-bipyridine), and their complete characterization, including single crystal X-ray diffraction, FTIR spectroscopy and thermal analysis (TGA/DTA) are reported. In especial, photophysical properties of Eu(III) complex have been studied in detail via both theoretical and experimental approaches. Crystal structures of 1–3 reveal that all compounds are isostructural and that each lanthanide ion is nine-coordinated by oxygen and nitrogen atoms in an overall distorted tricapped trigonal-prismatic geometry. Eu(III) complex structure was also calculated using the Sparkle model for lanthanide complexes and the intensity parameters (Ω{sub 2}, Ω{sub 4}, and Ω{sub 6}), calculated from the experimental data and from Sparkle/PM3 model. The theoretical emission quantum efficiencies obtained for Sparkle/PM3 structures are in excellent agreement with the experimental values, clearly attesting to the efficacy of the theoretical models. The theoretical procedure applied here shows that the europium binuclear compound displays a quantum yield about 65% suggesting that the system can be excellent for the development of efficient luminescent devices. Highlights: • First binuclear Ln{sup 3+}-hydrocinnamate have been synthesized and characterized. • Eu{sup 3+}, Tb{sup 3+} and Gd{sup 3+} complexes photoluminescence properties were investigated. • Theoretical approaches for Eu{sup 3+} complex luminescence has been performed. • An energy level diagram is used to establish the ligand-to-metal energy transfer. • 65% Quantum yield suggests an excellent system for luminescent devices.

  6. Structural and magnetic properties of Fe2P-type R6TTe2 compounds (R = Tb, Dy, Ho, Er, T = Fe, Co, Ru): Magnetic properties and specific features of magnetic entropy change

    Science.gov (United States)

    Morozkin, A. V.; Genchel, V. K.; Knotko, A. V.; Yapaskurt, V. O.; Yao, Jinlei; Quezado, S.; Malik, S. K.

    2018-02-01

    The magnetic properties and magnetic entropy changes of the Fe2P-type Ho6FeTe2, Ho6CoTe2, Er6CoTe2, Tb6RuTe2, Dy6RuTe2 and Ho6RuTe2 (space group P-62m, N 189, hP9) have been studied by means of bulk magnetization and heat capacity measurements. Also, the tentative magnetic entropy change ΔSm* = (∂M / ∂T) × H was used for characterization of magnetic ordering. Ho6FeTe2, Ho6CoTe2, Er6CoTe2, Tb6RuTe2, Dy6RuTe2 and Ho6RuTe2 exhibit complex field sensitive ferro-antiferromagnetic ordering. The correlation between the isothermal magnetic entropy change and the magnetic ordering of these compounds have been studied.

  7. Preparation and characterization of electroluminescent devices based on complexes of {beta}-diketonates of Tb{sup 3+}, Eu{sup 3+}, Gd{sup 3+} ions with macrocyclic ligands and UO{sub 2}{sup 2+} films; Preparacao e caracterizacao de dispositivos eletroluminescentes de complexos de {beta}-dicetonados de ions Tb{sup 3+}, Eu{sup 3+}, Gd{sup 3+} com ligantes macrociclicos e filmes de UO{sub 2}{sup 2+}

    Energy Technology Data Exchange (ETDEWEB)

    Gibelli, Edison Bessa

    2010-07-01

    Complexes containing Rare Earth ions are of great interest in the manufacture of electro luminescent devices as organic light emitting devices (OLED). These devices, using rare earth trivalent ions (TR{sup 3+}) as emitting centers, show high luminescence with extremely fine spectral bands due to the structure of their energy levels, long life time and high quantum efficiency. This work reports the preparation of Rare Earth {beta}-diketonate complexes (Tb{sup 3+}, Eu{sup 3+} and Gd{sup 3+}) and (tta - thenoyltrifluoroacetonate and acac - acetylacetonate) containing a ligand macrocyclic crown ether (DB18C6 - dibenzo18coroa6) and polymer films of UO{sub 2}{sup 2+}. The materials were characterized by complexometric titration with EDTA, CH elemental analysis, near infrared absorption spectroscopy, thermal analysis, X-ray diffraction (powder method) and luminescence spectroscopy. For manufacturing the OLED it was used the technique of deposition of thin films by physical vapor (PVD, Physical Vapor Deposition). (author)

  8. Magnetism of cyano-bridged Ln3+-M3+ complexes. Part II: one-dimensional complexes (Ln3+ = Eu, Tb, Dy, Ho, Er, Tm; M3+ = Fe or Co) with bpy as blocking ligand.

    Science.gov (United States)

    Figuerola, Albert; Ribas, Joan; Casanova, David; Maestro, Miguel; Alvarez, Santiago; Diaz, Carmen

    2005-10-03

    The reaction of Ln(NO3)3(aq) with K3[Fe(CN)6] or K3[Co(CN)6] and 2,2'-bipyridine in water/ethanol led to 13 one-dimensional complexes: trans-[M(CN)4(mu-CN)2Ln(H2O)4(bpy)]n.4nH2O.1.5nbpy (Ln = Eu3+, Tb3+, Dy3+, Ho3+, Er3+, Tm3+, Lu3+; M = Fe3+, Co3+). The structures for [EuFe]n (1), [TbFe]n (2), [DyFe]n (3), [HoFe]n (4), [ErFe]n (5), [TmFe]n (6), [LuFe]n (7), [EuCo]n (8), [TbCo]n (9), [DyCo]n (10), [HoCo]n (11), [ErCo]n (12), and [TmCo]n (13) have been solved: they crystallize in the triclinic space group P and are isomorphous. They exhibit a supramolecular architecture created by the interplay of coordinative, hydrogen bonding, and pi-pi interactions. A stereochemical study of the eight-vertex polyhedra of the lanthanide ions, based on continuous shape measures, is presented. The Ln3+-Fe3+ interaction is antiferromagnetic in [DyFe]n and [TbFe]n. For [EuFe]n, [HoFe]n, [ErFe]n, and [TmFe]n, there is no sign of any significant interaction. The magnetic behavior of [DyFe]n suggests the onset of weak long-range ferromagnetic ordering at 2.5 K.

  9. Thermometry properties of Er, Yb–Gd2O2S microparticles: dependence on the excitation mode (cw versus pulsed excitation) and excitation wavelength (980 nm versus 1500 nm)

    Science.gov (United States)

    Avram, Daniel; Tiseanu, Carmen

    2018-04-01

    Herein, we present a first report on the luminescence thermometry properties of Er, Yb doped Gd2O2S microparticles under near infrared up-conversion excitation at 980 and 1500 nm measured in the 280–800 K interval. The thermometry properties are assessed using both cw and ns pulsed excitation as well as tuning the excitation wavelength across Yb and Er absorption profiles. For low cw (300 mW cm‑1) and pulsed ns (400 ÷ 550 mW cm‑1) excitation modes, no thermal load is observed. At room-temperature (280 K), the maximum relative sensitivity values are comparable under pulsed excitation at 980 and 1500 nm, around ∼0.01 and ∼0.008% K‑1, respectively. In addition, a relative intense up-conversion emission at 980 nm under excitation at 1500 nm is measured. Our findings evidence attractive up-conversion and thermometry properties Er, Yb doped Gd2O2S under near-infrared excitation and highlight the need to explore further these properties in the nanoparticulate regime.

  10. Magnetic properties of the charge density wave compounds RTe3, R=Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er & Tm

    Energy Technology Data Exchange (ETDEWEB)

    Ru, N.; Chu, J.-H.; Fisher, I.R.; /Stanford U., Geballe Lab.

    2009-12-14

    The antiferromagnetic transition is investigated in the rare-earth (R) tritelluride RTe{sub 3} family of charge density wave (CDW) compounds via specific heat, magnetization and resistivity measurements. Observation of the opening of a superzone gap in the resistivity of DyTe{sub 3} indicates that additional nesting of the reconstructed Fermi surface in the CDW state plays an important role in determining the magnetic structure.

  11. Magnetic and structural features of RNi2B2C and RNiBC (R=Er, Ho, Dy, Tb, Gd) superconducting compounds

    OpenAIRE

    Baggio-Saitovitch, E. M.; Sánchez, D. R.; Micklitz, H.

    2002-01-01

    Temperature dependent Mössbauer spectroscopy on 57Fe doped (1 at % of Ni) RNi2B2C and RNiBC provided clear evidence of a pair-breaking field at the Ni site for non-superconducting compounds. This field is not present in the superconducting collinear AF DyNi2B2C, however it appears when this compound is diluted with non-magnetic Lu (Dy1-xLu xNi2B2C). Important local information on the spin structure of the R magnetic moments is obtained for both systems. The local symmetries of RNi2B2C and RNi...

  12. Angle-resolved photoemission study of the evolution of band structure and charge density wave properties in RTe3 (R= Y, La, Ce, Sm, Gd, Tb and Dy)

    Energy Technology Data Exchange (ETDEWEB)

    Brouet, V.; Yang, W.L.; Zhou, X.J.; Hussain, Z.; Moore, R.G.; He, R.; Lu, D.H.; Shen, Z.X.; Laverock, J.; Dugdale, S.; Ru, N.; Fisher, I.R.

    2010-02-15

    We present a detailed ARPES investigation of the RTe{sub 3} family, which sets this system as an ideal 'textbook' example for the formation of a nesting driven Charge Density Wave (CDW). This family indeed exhibits the full range of phenomena that can be associated to CDW instabilities, from the opening of large gaps on the best nested parts of Fermi Surface (FS) (up to 0.4eV), to the existence of residual metallic pockets. ARPES is the best suited technique to characterize these features, thanks to its unique ability to resolve the electronic structure in k-space. An additional advantage of RTe{sub 3} is that the band structure can be very accurately described by a simple 2D tight-binding (TB) model, which allows one to understand and easily reproduce many characteristics of the CDW. In this paper, we first establish the main features of the electronic structure, by comparing our ARPES measurements with Linear Muffin-Tin Orbital band calculations. We use this to define the validity and limits of the TB model. We then present a complete description of the CDW properties and, for the first time, of their strong evolution as a function of R. Using simple models, we are able to reproduce perfectly the evolution of gaps in k-space, the evolution of the CDW wave vector with R and the shape of the residual metallic pockets. Finally, we give an estimation of the CDW interaction parameters and find that the change in the electronic density of states n(Ef), due to lattice expansion when different R ions are inserted, has the correct order of magnitude to explain the evolution of the CDW properties.

  13. ARPES study of the evolution of band structure and charge density wave properties in RTe3 ( R=Y , La, Ce, Sm, Gd, Tb, and Dy)

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, Zahid; Brouet, Veronique; Yang, Wanli; Zhou, Xingjiang; Hussain, Zahid; Moore, R.G.; He, R.; Lu, D. H.; Shen, Z.X.; Laverock, J.; Dugdale, S.B.; Ru, N.; Fisher, R.

    2008-01-16

    We present a detailed angle-resolved photoemission spectroscopy (ARPES) investigation of the RTe3 family, which sets this system as an ideal"textbook" example for the formation of a nesting driven charge density wave (CDW). This family indeed exhibits the full range of phenomena that can be associated to CDWinstabilities, from the opening of large gaps on the best nested parts of Fermi surface (up to 0.4 eV), to the existence of residual metallic pockets. ARPES is the best suited technique to characterize these features, thanks to its unique ability to resolve the electronic structure in k space. An additional advantage of RTe3 is that theband structure can be very accurately described by a simple two dimensional tight-binding (TB) model, which allows one to understand and easily reproduce many characteristics of the CDW. In this paper, we first establish the main features of the electronic structure by comparing our ARPES measurements with the linear muffin-tinorbital band calculations. We use this to define the validity and limits of the TB model. We then present a complete description of the CDW properties and of their strong evolution as a function of R. Using simple models, we are able to reproduce perfectly the evolution of gaps in k space, the evolution of the CDW wave vector with R, and the shape of the residual metallic pockets. Finally, we give an estimation of the CDWinteraction parameters and find that the change in the electronic density of states n (EF), due to lattice expansion when different R ions are inserted, has the correct order of magnitude to explain the evolution of the CDW properties.

  14. Synthesis, magnetism and Mössbauer studies of tetranuclear heterometallic {Fe(III)2Ln2}(Ln = Gd, Dy, Tb) complexes: evidence of slow relaxation of magnetization in the terbium analogue.

    Science.gov (United States)

    Bag, Prasenjit; Goura, Joydeb; Mereacre, Valeriu; Novitchi, Ghenadie; Powell, Annie K; Chandrasekhar, Vadapalli

    2014-11-21

    A new family of tetranuclear heterometallic assemblies, [Fe(III)2Gd2(H2L)4(η(2)-NO3)2]·2ClO4·2CH3OH·2H2O (1), [Fe(III)2Dy2(H2L)4(η(2)-NO3)2]·2ClO4·2CH3OH·2H2O (2), [Fe(III)2Tb2(H2L)4(η(2)-NO3)2]·2ClO4·2CH3OH·2H2O (3), have been synthesized employing a multi-dentate Schiff-base ligand, (E)-2,2'-(2-hydroxy-3-((2-hydroxyphenylimino)methyl)-5-methylbenzylazanediyl)-diethanol (H4L), Fe(ClO4)2·6H2O, and Ln(III) nitrate salts. These compounds have been structurally characterized by various analytical and spectroscopic techniques. The molecular structures of 1-3 have been confirmed by single crystal X-ray crystallography. All the three complexes contain two Fe(III) ions at the periphery and two Ln(III) ions in the centre. The entire assembly is held together by four doubly deprotonated [LH2](2-) ligands. All the three complexes (1-3) are dicationic in nature and possess an overall Z-type topology. Magnetic measurements reveal the presence of predominant ferromagnetic coupling for all the three compounds at low temperature. The presence of a frequency-dependent out-of-phase signal in the imaginary part of the ac susceptibility plot suggests a slow relaxation of magnetization for 3 (Fe(III)2Tb2). Furthermore, the magnetization dynamics of all the three complexes have been corroborated by Mössbauer spectroscopy.

  15. Raman and Fluorescence Spectroscopy of CeO2, Er2O3, Nd2O3, Tm2O3, Yb2O3, La2O3, and Tb4O7

    Directory of Open Access Journals (Sweden)

    Jianlan Cui

    2015-01-01

    Full Text Available To better understand and ascertain the mechanisms of flotation reagent interaction with rare earth (RE minerals, it is necessary to determine the physical and chemical properties of the constituent components. Seven rare earth oxides (CeO2, Er2O3, Nd2O3, Tm2O3, Yb2O3, La2O3, and Tb4O7 that cover the rare earth elements (REEs from light to heavy REEs have been investigated using Raman spectroscopy. Multiple laser sources (wavelengths of 325 nm, 442 nm, 514 nm, and 632.8 nm for the Raman shift ranges from 100 cm−1 to 5000 cm−1 of these excitations were used for each individual rare earth oxide. Raman shifts and fluorescence emission have been identified. Theoretical energy levels for Er, Nd, and Yb were used for the interpretation of fluorescence emission. The experimental results showed good agreement with the theoretical calculation for Er2O3 and Nd2O3. Additional fluorescence emission was observed with Yb2O3 that did not fit the reported energy level diagram. Tb4O7 was observed undergoing laser induced changes during examination.

  16. Impact of firing temperature on multi-wavelength selective Stokes and anti-Stokes luminescent behavior by Gd2O2S:Er,Yb phosphor and its application in solar energy harvesting

    Science.gov (United States)

    Kataria, V.; Mehta, D. S.

    2018-04-01

    Erbium (Er3+)-ytterbium (Yb3+) doped gadolinium oxysulphide (Gd2O2S) phosphor has been developed via a facile method of solid-state flux fusion, and offers two-fold spectrum modification with highly intense Stokes and anti-Stokes shift. The effect of the firing cycle on the photoluminescent response and morphology of Gd2O2S:Er,Yb is scrutinized, wherein the firing temperature was varied (1000 °C-1250 °C), keeping firing time and all other parameters constant. Interestingly, the nanostructures fired below 1150 °C showed nanorods of diameter ~200 nm and length ~1-2 µm, whereas firing at 1150 °C and above rendered nanospheres with small diameter, ~350 nm. Highly bright upconversion (UC) emission was achieved even under an extremely low excitation power density of 800 µW cm-2 from a 980 nm laser, and was comfortably visible to the naked eye. The incident power dependent studies disclosed increase in UC-emission intensity with increasing excitation power and a quasi-linear dependence on excitation power density. Intense characteristic UC-emission of Er3+ excited states at 525 nm, 556 nm and 668 nm were observed, and the green emission band was found to be dominant over the red band in intensity. Concurrently, downconversion (DC) emission at 556 nm and 669 nm was also exhibited under ultraviolet excitation (285 nm and 380 nm), with the red band being more powerful than the green, unlike UC-emission. Firing temperature dependent studies divulged the dependence of luminescence intensity on the firing cycle of the luminophore and formation of the respective luminescent phase. The UC-emission intensity was found to be maximum for samples fired at 1150 °C, whereas samples fired at 1000 °C showed the highest DC-emission intensity. The excitation and emission profile of single Gd2O2S:Er,Yb phosphor lying in the desired spectral region and as a dual spectral converter marks its possible application for enhanced harvesting of sunlight.

  17. Spontaneous polarization and pyroelectric effect in improper ferroelectrics-ferroelastics Gd2(MoO4)3 and Tb2(MoO4)3 at low temperature

    International Nuclear Information System (INIS)

    Matyjasik, S; Shaldin, Yu.V.

    2013-01-01

    Experimental dependencies for spontaneous polarization ΔP s (T) and pyroelectric coefficient γ s (T)for Gd 2 (MoO 4 ) 3 (GMO) and Tb 2 (MoO 4 ) 3 (TMO) reported here differs from those for intrinsic ferroelectrics. We found fundamental distinction in GMO and TMO samples behavior at their repolarization at the fixed temperatures 300 and 4.2 K. In TMO monodomainization temperature does not affect experimental data, while in GMO monodomainization at 4.2 K results in increase of ΔP s (T) by order of magnitude at 85 K and γ s (T) dependence shows well-defined anomalies, reaching a record magnitude of 3 centre dot 10 -4 C/(m 2 centre dot K) at T = 25 K. At T = 200 K the pyroelectric coefficients values are -1.45 centre dot 10 -6 C/(m 2 centre dot K) and-1.8 centre dot 10 -6 C/(m 2 centre dot K). Taking into account our data, results related to transformation of structure in (001) plane and symmetry reasons we suggested crystallographic model of GMO type improper ferroelectric. It is formed by four meso-tetrahedrons constructed of three coordination tetrahedrons MO 4 (a, b and c types). In the framework of this model we discuss the physical meaning of pseudodeviator Q 12 *, coefficient, that initiate the phase transition at T > 433 K from noncentrosymmetric phase (mm2) to another one (4-bar2m).

  18. Crystallographic and magnetic properties of R sub 3 Fe sub 2 sub 9 sub - sub x V sub x N sub 4 (R=Y, Ce, Nd, Sm, Gd, Tb, and Dy)

    CERN Document Server

    Han Xiu Feng; Li Qi; Zhang Mao Cai; Zhou Shou Zeng

    1998-01-01

    A systematic investigation of crystallographic and magnetic properties of nitride R sub 3 Fe sub 2 sub 9 sub - sub x V sub x N sub 4 (R = Y, Ce, Nd, Sm, Gd, Tb, and Dy) has been performed. Nitrogenation leads to a relative volume expansion of about 6%. The lattice constants and unit cell volume decrease with increasing rare-earth atomic number from Nd to Dy, reflecting the lanthanide contraction. On average, the Curie temperature increases due to the nitrogenation to about 200 K compared with its parent compound. Generally speaking, nitrogenation also results in a remarkable improvement of the saturation magnetization and anisotropy fields at 4.2 K and room temperature for R sub 3 Fe sub 2 sub 9 sub - sub x V sub x N sub 4 compared with their parent compounds. The transition temperature indicates the spin reorientations of R sub 3 Fe sub 2 sub 9 sub - sub x V sub x N sub 4 for R Nd and Sm are at around 375 and 370 K which are higher than that of R sub 3 Fe sub 2 sub 9 sub - sub x V sub x for R = Nd and Sm 145...

  19. TB Terms

    Science.gov (United States)

    ... Studies Consortium Research Projects Publications TB Trials Consortium Study Descriptions Background Behavioral & Social Science Research Infection Control TB in Specific Populations African-American Community Stop TB in the African-American ...

  20. Magnetic phase transitions in TbFe sub 2 Al sub 1 sub 0 , HoFe sub 2 Al sub 1 sub 0 and ErFe sub 2 Al sub 1 sub 0

    CERN Document Server

    Reehuis, M; Krimmel, A; Scheidt, E W; Stüsser, N; Loidl, A; Jeitschko, W

    2003-01-01

    The magnetic order of the orthorhombic aluminides TbFe sub 2 Al sub 1 sub 0 , HoFe sub 2 Al sub 1 sub 0 and ErFe sub 2 Al sub 1 sub 0 (space group Cmcm) has been studied by specific heat and magnetic measurements, as well as by neutron powder diffraction down to 100 mK and in external fields up to 5 T. Only the rare-earth ions carry a magnetic moment. At T = 1.5 K the terbium moments in TbFe sub 2 Al sub 1 sub 0 show a square-wave modulated magnetic order with wavevector k = (0, 0.7977, 0) and a moment direction parallel to the a-axis. At a critical field of H sub c sub 1 = 0.9 T one of ten spins is forced to flip, going into an intermediate ferrimagnetic phase that is stable up to the critical field H sub c sub 2 = 1.8 T. Above this field finally all the rest of the spins flip, resulting in a ferromagnetic order of the terbium moments. ErFe sub 2 Al sub 1 sub 0 orders antiferromagnetically below T sub N 1.77(7) K with a similar magnetic structure characterized by a wavevector k (0, approx 0.8, 0). In contras...

  1. Magnetic characterization of microcrystalline Na3Ln0.99–xEr0.01Crx(PO42 orthophosphates synthesized by Pechini method (Ln = La, Gd

    Directory of Open Access Journals (Sweden)

    Kaczmarek S.M.

    2018-03-01

    Full Text Available Na3Ln(PO42 orthophosphates (Ln = La, Gd doped with Er3+ and co-doped with Cr3+ ions were synthesized by Pechini method and characterized by electron paramagnetic resonance (EPR and magnetic susceptibility measurements. Low temperature EPR spectra were detected and analyzed in terms of temperature dependence and the structure of the obtained materials. They show that erbium and chromium ions substitute Ln3+ and also Na+ ions or Na+ channels forming complex EPR spectra. Both kinds of ions reveal ferromagnetic type of interaction which shows some anomaly at the temperature between 10 K and 15 K. Magnetic susceptibility reveals a weak antiferromagnetic kind of interaction dominating in the whole temperature range, from 3.5 to 300 K.

  2. (Gd1−xErx)5Si2Ge2 compounds

    Indian Academy of Sciences (India)

    (RE = Ce, Pr, Sm, Tb, Dy, Er, Ho, Y) compounds (Tegus and Dagula 2002; Yang et al 2003; ..... 161K. 164K. 167K. 170K. 173K. 176K. 179K. 182K. 185K. 188K. 191K. 194K. 197K. 200K. Figure 5. Magnetization isotherm curves of (Gd1−x Erx )5Si2Ge2 compounds measured under field of 0–2 T: (a) x = 0, (b) x = 0·05, (c) x ...

  3. Spontaneous polarization and pyroelectric effect in the improper ferroelectrics-ferroelastics Gd2(MoO4)3 and Tb2(MoO4)3 at low temperatures

    Science.gov (United States)

    Matyjasik, S.; Shaldin, Yu. V.

    2013-11-01

    The experimental variations in the spontaneous polarization ΔPs(T) and pyroelectric coefficient γs(T) for Gd2(MoO4)3 (GMO) and Tb2(MoO4)3 (TMO) at low temperatures reported here differ from those for intrinsic ferroelectrics. A fundamental difference is found in the repolarization behavior of samples of GMO and TMO at fixed temperatures of 300 and 4.2 K. While the single domain formation temperature essentially has no effect on the measurements for TMO, a fundamental difference is observed in the case of GMO: single domain formation in the latter at 4.2 K leads to an order of magnitude increase in ΔPs at T > 85 K and distinct anomalies are observed in γs(T), at one of which the pyroelectric coefficient reaches a record peak of 3 × 10-4 C/(m2.K) at T = 25 K. At T = 200 K the pyroelectric coefficients equal -1.45 and -1.8 in units of 10-6 C/(m2.K). Based on these results and taking published data on the rotational structural transformation in the (001) plane and symmetry considerations into account, we propose a crystal physical model for GMO-type improper ferroelectrics consisting of four mesotetrahedra, each of which is made up of three different types (a, b, c) of MoO4 coordination tetrahedra. The physical significance of the pseudodeviator coefficient Q12*, which initiates the phase transition at T > 433 K from one non-centrally symmetric phase (mm2) into another (4¯2m), is discussed in terms of this model.

  4. Facile synthesis and luminescence properties of Y2O3:Ln(3+) (Ln(3+) = Eu(3+), Tb(3+), Dy(3+), Sm(3+), Er(3+), Ho(3+), Tm(3+), Yb(3+)/Er(3+), Yb(3+)/Tm(3+), Yb(3+)/Ho(3+)) microspheres.

    Science.gov (United States)

    Xu, Zhenhe; Zhao, Qian; Ren, Baoyi; You, Lixin; Sun, Yaguang

    2014-08-01

    Multicolor and monodisperse Y2O3:Ln(3+) (Ln(3+) = Eu(3+), Tb(3+), Dy(3+), Sm(3+), Er(3+), Ho(3+), Tm(3+), Yb(3+)/Er(3+), Yb(3+)/Ho(3+)) microspheres were prepared through a facile urea-assisted homogeneous precipitation method followed by a subsequent calcination process. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectrum (EDS), Fourier transformed infrared (FT-IR), thermogravimetric analysis (TGA), photoluminescence (PL) and cathodoluminescence (CL) spectra were employed to characterize the samples. The XRD results reveal that the as-prepared spheres can be well indexed to cubic Y2O3 phase with high purity. The SEM and TEM images show the obtained Y2O3:Ln(3+) samples consist of regular nanospheres with the mean diameter of 350 nm. And the possible formation mechanism is also proposed. Upon ultraviolet and low-voltage electron beams excitation, Y2O3:Ln(3+) (Ln(3+) = Eu(3+), Tb(3+), Dy(3+), Sm(3+), Er(3+), Ho(3+), Tm(3+)) samples exhibit respective bright red (Eu(3+), (5)D0 --> (7)F2), green (Tb(3+), (5)D4 --> (7)F5), blue (Dy(3+), (4)F9/2 --> (6)H13/2), yellow (Sm(3+), (4)G5/2 --> (6)H7/2), green (Er(3+), (4)S3/2 --> (4)I15/2), green (Ho(3+), (5)S2 --> (5)I8), blue (Tm(3+), (1)D2 --> (3)F4) down-conversion (DC) emissions. Under 980 nm NIR irradiation, Y2O3:Ln(3+) (Ln(3+) = Yb(3+)/Er(3+), Yb(3+)/Tm(3+) and Yb(3+)/Ho(3+)) exhibit characteristic up-conversion (UC) emissions of green (Er(3+), (2)H11/2, (4)S3/2, (2)H11/2 --> (4)I5/2), blue (Tm(3+), (1)G4 --> (3)H6) and green (Ho(3+), (5)F4, (5)S2 --> (5)I8), respectively. These merits of multicolor emissions in the visible region endow this kind of material with potential applications in the field of light display systems, lasers, and optoelectronic devices.

  5. Production, characterization and application of Gd{sub 2}O{sub 3} and Er{sub 2}O{sub 3} nanoparticles as radiosensitizers in radiotherapy beams; Produção, caracterização e aplicação de nanopartículas de Gd{sub 2}O{sub 3} e Er{sub 2}O{sub 3} como radiossensibilizadores em feixes de radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Corrêa, Eduardo de Lima

    2017-07-01

    In this study Gd{sub 2}O{sub 3} and Er{sub 2}O{sub 3} nanoparticles were produced for application as radiosensitizers in radiotherapy beams. They were synthesized at the Hyperfine Interactions Laboratory, IPEN, using thermal decomposition method and characterized by X-ray diffraction, to verify crystalline structure, transmission electron microscopy, to obtain information about shape, size and size distribution, neutron activation analysis, whereby it was possible to determine samples purity and gadolinium and erbium concentration. Magnetization and perturbed γ-γ angular correlation (PAC) measurements were performed in order to study particles magnetic behavior and quadrupole interactions, respectively. Characterization results showed a bixbyite structure, 5 nm diameter post-synthesis particles with narrow size distribution. Rare-earth mass determination in each sample was important to perform normalization in magnetic susceptibility measurements, making possible the view of a high magnetization under 30 K for post-synthesis samples, what was not observed in larger particles, together with an effective magnetic moment enhancement for nanoparticles, not seen in bulk samples, and a change in the antiferromagnetic ordering temperature for Er{sub 2}O{sub 3}. PAC spectroscopy results show possible surface effects. The absence of a well-defined frequency in 5 nm samples indicates the amount of {sup 111}In({sup 111}Cd) at particle surface is bigger than in the core, resulting in a non-evident hyperfine interaction between the probe nuclei and the host. The X-ray diffraction and PAC spectroscopy joint was vital to understand the particles structural damage caused by {sup 60}Co irradiation. About radiosensitizer measurements a dose enhancement factor (DEF) of up to 1,67 and 1,09 for Gd{sub 2}O{sub 3} nanoparticles under {sup 60}Co and 6MV irradiation, respectively, were observed. Under same conditions DEF values of up to 1,37 and 1,06 were found for Er{sub 2}O{sub 3

  6. Ternary rare earth metal boride carbides containing two-dimensional boron carbon network: The crystal and electronic structure of R2B4C (R=Tb, Dy, Ho, Er)

    Science.gov (United States)

    Babizhetskyy, Volodymyr; Zheng, Chong; Mattausch, Hansjürgen; Simon, Arndt

    2007-12-01

    The ternary rare earth boride carbides R2B4C (R=Tb, Dy, Ho, Er) have been synthesized by reacting the elements at temperatures between 1800 and 2000K. The crystal structure of Dy2B4C has been determined from single-crystal X-ray diffraction data. It crystallizes in a new structure type in the orthorhombic space group Immm (a=3.2772(6) Å, b=6.567(2) Å, c=7.542(1) Å, Z=2, R1=0.035 (wR2=0.10) for 224 reflections with Io>2σ(Io)). Boron atoms form infinite chains of fused B6 rings in [100] joined with carbon atoms into planar, two-dimensional networks which alternate with planar sheets of rare earth metal atoms. The electronic structure of Dy2B4C was also analyzed using the tight-binding extended Hückel method.

  7. Comparative thermometric properties of bi-functional Er3+–Yb3+ doped rare earth (RE = Y, Gd and La) molybdates

    Science.gov (United States)

    Sinha, Shriya; Mahata, Manoj Kumar; Kumar, Kaushal

    2018-02-01

    The molybdate compounds as luminescent medium have received great attention of recent research due to their excellent intrinsic optical properties. Therefore, the investigation on the optical thermometry and nanoheating effect in Er3+–Yb3+ doped molybdates of yttrium (EYYMO), gadolinium (EYGMO) and lanthanum (EYLMO) nanophosphors is reported herein. The temperature dependent fluorescence intensity ratio of green (525 and 548 nm) emission bands of Er3+ ions were analyzed within 300–500 K temperature range to determine the thermal behavior. The comparative temperature sensitivity of the materials has been found to depend on the phonon energy of their own. The thermal sensitivity is higher in the materials with low phonon energy. The intensity ratio of the green emission bands has been found to alter with the laser excitation density, which can be used to estimate the induced temperature in the materials. Furthermore, the photothermal conversion efficiency is calculated in the water dispersed samples and the maximum photothermal conversion efficiency of 49.6% is achieved for EYGMO nanophosphor. Comparative experimental results explore unequal thermal sensing and induced optical heating in the three rare earth molybdates. The optical properties of the green emitting molybdates are interesting for temperature sensing and optical heating applications.

  8. Ternary gallides RE{sub 4}Rh{sub 9}Ga{sub 5}, RE{sub 5}Rh{sub 12}Ga{sub 7} and RE{sub 7}Rh{sub 18}Ga{sub 11} (RE=Y, La-Nd, Sm, Gd, Tb). Intergrowth structures with MgCu{sub 2} and CaCu{sub 5} related slabs

    Energy Technology Data Exchange (ETDEWEB)

    Seidel, Stefan; Rodewald, Ute C.; Poettgen, Rainer [Univ. Muenster (Germany). Inst. fuer Anorganische und Analytische Chemie; Janka, Oliver [Univ. Oldenburg (Germany). Inst. fuer Chemie

    2017-07-01

    Fourteen ternary gallides RE{sub 4}Rh{sub 9}Ga{sub 5}, RE{sub 5}Rh{sub 12}Ga{sub 7} and RE{sub 7}Rh{sub 18}Ga{sub 11} (RE=Y, La-Nd, Sm, Gd, Tb) were synthesized from the elements by arc-melting, followed by different annealing sequences either in muffle or induction furnaces. The samples were characterized through Guinier powder patterns and the crystal structures of Ce{sub 4}Rh{sub 9}Ga{sub 5}, Ce{sub 5}Rh{sub 12}Ga{sub 7}, Ce{sub 7}Rh{sub 18}Ga{sub 11}, Nd{sub 5}Rh{sub 10.44(4)}Ga{sub 8.56(4)}, Nd{sub 4}Rh{sub 9}Ga{sub 5} and Gd{sub 4}Rh{sub 9}Ga{sub 5} were refined from single crystal X-ray diffractometer data. The new gallides are the n=2, 3 and 5 members of the RE{sub 2+n} Rh{sub 3+3n} Ga{sub 1+2n} structure series in the Parthe intergrowth concept. The slabs of these intergrowth structures derive from the cubic Laves phase MgCu{sub 2} (Mg{sub 2}Ni{sub 3}Si as ternary variant) and CaCu{sub 5} (CeCo{sub 3}B{sub 2} as ternary variant). Only the Nd{sub 5}Rh{sub 10.44(4)}Ga{sub 8.56(4)} crystal shows Rh/Ga mixing within the Laves type slabs. Magnetic susceptibility measurements reveal Pauli paramagnetism for Y{sub 4}Rh{sub 9}Ga{sub 5} and Curie-Weiss paramagnetism for Gd{sub 4}Rh{sub 9}Ga{sub 5} and Tb{sub 4}Rh{sub 9}Ga{sub 5}. Low-temperature data show ferromagnetic ordering at T{sub C}=78.1 (Gd{sub 4}Rh{sub 9}Ga{sub 5}) and 55.8 K (Tb{sub 4}Rh{sub 9}Ga{sub 5}).

  9. Local Bi-O bonds correlated with infrared emission properties in triply doped Gd2.95Yb0.02Bi0.02Er0.01Ga5O12 via temperature-dependent Raman spectra and x-ray absorption fine structure analysis.

    Science.gov (United States)

    Tong, Liping; Saito, Katsuhiko; Guo, Qixin; Zhou, Han; Guo, Xingmei; Fan, Tongxiang; Zhang, Di

    2018-03-28

    A correlation function between the Raman intensities and the nearest-neighbor mean-square relative displacement (MSRD) [Formula: see text] of local Bi-O bonds is successfully established based on x-ray absorption fine structure (XAFS) and temperature-dependent Raman spectra in the temperature range 77-300 K in amorphous and crystalline Gd 2.95 Yb 0.02 Bi 0.02 Er 0.01 Ga 5 O 12 . The structural symmetries of Gd 2.95 Yb 0.02 Bi 0.02 Er 0.01 Ga 5 O 12 are described by using [Formula: see text] of local Bi-O bonds. More importantly, Gd 2.95 Yb 0.02 Bi 0.02 Er 0.01 Ga 5 O 12 is found to show excellent infrared (IR) emission properties due to changes in Bi-O bonds, and the IR emission intensities are found to depend on [Formula: see text], by using temperature-dependent photoluminescence spectroscopy. The maximum emission intensity at 1533 nm is obtained when [Formula: see text] [Formula: see text] at the lowest symmetry. This work shows that temperature-dependent Raman intensities can be used effectively to analyze the local covalent bonds around absorbing atoms as well as to study the emission properties of this visible-light-activated IR luminophor.

  10. Local Bi–O bonds correlated with infrared emission properties in triply doped Gd2.95Yb0.02Bi0.02Er0.01Ga5O12 via temperature-dependent Raman spectra and x-ray absorption fine structure analysis

    Science.gov (United States)

    Tong, Liping; Saito, Katsuhiko; Guo, Qixin; Zhou, Han; Guo, Xingmei; Fan, Tongxiang; Zhang, Di

    2018-03-01

    A correlation function between the Raman intensities and the nearest-neighbor mean-square relative displacement (MSRD) σ2 of local Bi–O bonds is successfully established based on x-ray absorption fine structure (XAFS) and temperature-dependent Raman spectra in the temperature range 77–300 K in amorphous and crystalline Gd2.95Yb0.02Bi0.02Er0.01Ga5O12. The structural symmetries of Gd2.95Yb0.02Bi0.02Er0.01Ga5O12 are described by using σ2 of local Bi–O bonds. More importantly, Gd2.95Yb0.02Bi0.02Er0.01Ga5O12 is found to show excellent infrared (IR) emission properties due to changes in Bi–O bonds, and the IR emission intensities are found to depend on σ2 , by using temperature-dependent photoluminescence spectroscopy. The maximum emission intensity at 1533 nm is obtained when σ^2∼0.003 {\\mathringA} at the lowest symmetry. This work shows that temperature-dependent Raman intensities can be used effectively to analyze the local covalent bonds around absorbing atoms as well as to study the emission properties of this visible-light-activated IR luminophor.

  11. Diode-pumped Er3+:Yb3+:NaCe0.43Gd0.57(WO4)2 pulse laser passively Q -switched with a Co2+:Mg0.4Al2.4O4 saturable absorber at 1.53 μ m

    International Nuclear Information System (INIS)

    Chen, Y J; Huang, J H; Lin, Y F; Luo, Z D; Huang, Y D; Zou, Y Q

    2014-01-01

    Based on the long fluorescence lifetime of upper laser level 4 I 13/2 of Er 3+ ions and high 1.5−1.6 μm laser operation efficiency, an Er 3+ :Y b 3+ :NaCe 0.43 Gd 0.57 (WO 4 ) 2 crystal was used to generate a Q-switched pulse laser with high energy and low threshold. End-pumped by a 970 nm diode laser, a passively Q-switched 1.5−1.6 μm pulse laser was first realized in an Er 3+ and Y b 3+ co-doped tungstate crystal, when a Co 2+ :Mg 0.4 Al 2.4 O 4 spinel crystal was used as saturable absorber. A 1.53 μm pulse laser with about 22 μJ energy, 76 ns duration and 21 kHz repetition rate was obtained at an absorbed pump power of 12 W in a c-cut 1.7-mm-thick Er 3+ :Y b 3+ :NaCe 0.43 Gd 0.57 (WO 4 ) 2 crystal. (paper)

  12. Tuberculosis (TB)

    Science.gov (United States)

    ... with facebook share with twitter share with linkedin Tuberculosis Go to Information for Researchers ► Tuberculosis (TB) is ... are drug resistant. Why Is the Study of Tuberculosis a Priority for NIAID? Tuberculosis is one of ...

  13. Study of amorphous semiconductors doped with rare earths (Gd and Er) and conducting polymers by EPR techniques and magnetic susceptibility; Estudo de semicondutores amorfos dopados com terras raras (Gd e Er) e de polimeros condutores atraves das tecnicas de RPE e susceptibilidade magnetica

    Energy Technology Data Exchange (ETDEWEB)

    Sercheli, Mauricio da Silva

    1999-07-01

    This thesis involves the study of amorphous semiconductors and conducting polymers, which have been characterized by EPR and magnetic susceptibility measurements, and to a lesser extent by Raman spectroscopy and RBS. The semiconductors were studied using thin films of silicon doped with rare earth metals, e.g. erbium and gadolinium, which had their magnetic properties studied. Using these studies we could determine the state of valence of the rare earths as well as their concentrations in the silicon matrix. According to our results, the valence of the rare earth metal ions is 3+, and we were able to conclude that 4f electronic shells could not be used for the calculation of the conducting band in this system. Furthermore, the analysis of the data on the magnetic susceptibility of the Er{sup 3+} ion with cubic crystalline acting field, gave us the opportunity to estimate the overall splitting of their electronic states for the first time. The conducting polymers were studied using samples of poly(3-methylthiophene) doped with ClO{sub 4}{sup -}, which show a phase transition in the range of 230 K to 130 K. The electron paramagnetic resonance also gives important information on the crystallization, doping level and the presence of polarons or bipolarons in conducting polymers. (author)

  14. Tunable magneto-caloric effect in Gd1-xTbx heterostructures thin film

    Science.gov (United States)

    Lambert, C. H.; El Hadri, M. S.; Hamedoun, M.; Benyoussef, A.; Mounkachi, O.; Mangin, S.

    2017-12-01

    The magnetic and magneto-caloric properties of (Gd1-xTbx) alloy thin films and [Gd/Tb] multilayers have been investigated. All the samples had a total thickness of 100 nm and were deposited by DC sputtering. By changing the composition of the system, the ordering temperature (Tc) and the magnetic entropy changes of the compounds could be tuned. The results show that the Tc of the alloy thin films is close to 270 K for x = 0.2. Moreover, creating [Gd/Tb] multilayers with the same thickness and concentration of the studied Gd80Tb20 alloy film enables to strongly increase the relative cooling power, and reach values twice as big as from the corresponding alloys. These results suggest that nanostructuring of [Gd/Tb] multilayers may be a promising route to tailor the magnetocaloric response of materials.

  15. resistant TB

    African Journals Online (AJOL)

    2014-01-24

    Jan 24, 2014 ... Background. Symptomatic symmetrical peripheral neuropathy (SSPN) is common in patients with HIV infection. It is also a common adverse event associated with both tuberculosis (TB) treatment and antiretroviral therapy (ART), particularly stavudine. While tenofovir is the one of recommended first-line ...

  16. R = Y, Tb, Dy, Ho and Er

    Indian Academy of Sciences (India)

    also found with rare-earth elements, silver and lead (Gulay and Wolcyrz 2001) and in R–Ag–Sn systems, ... forms DFT calculations using the local density approxima- tion with wavefunctions as a basis. Kohn–Sham ... core electrons are described by atomic wavefunctions which are solved relativistically using the current ...

  17. Upconversion luminescence in BaYF{sub 5}, BaGdF{sub 5} and BaLuF{sub 5} nanocrystals doped with Yb{sup 3+}/Ho{sup 3+}, Yb{sup 3+}/Er{sup 3+} or Yb{sup 3+}/Tm{sup 3+} ions

    Energy Technology Data Exchange (ETDEWEB)

    Grzyb, Tomasz, E-mail: tgrzyb@amu.edu.pl [Department of Rare Earths, Faculty of Chemistry, Adam Mickiewicz University, Umultowska 89b, 61-614 Poznań (Poland); Balabhadra, Sangeetha [Department of Physics, University of Aveiro, Campus Universitario de Santiago, 3810-193, Aveiro (Portugal); Przybylska, Dominika; Węcławiak, Mariusz [Department of Rare Earths, Faculty of Chemistry, Adam Mickiewicz University, Umultowska 89b, 61-614 Poznań (Poland)

    2015-11-15

    Nanomaterials based on BaREF{sub 5} fluorides (where RE = Y, Gd and Lu), doped with lanthanide ions Yb{sup 3+}/Ln{sup 3+} (Ln{sup 3+} = Er, Ho or Tm) were synthesized by microwave assisted hydrothermal method. The method of synthesis, structural and morphological properties are reported and discussed. The products obtained showed visible upconversion luminescence excited by the laser light of wavelength of 975 nm as a consequence of energy transfer between Yb{sup 3+} and remaining Ln{sup 3+} dopant ions. Their spectroscopic properties were characterized on the basis of excitation and emission spectra. Also luminescence decays and emission power dependences are presented and analysed. The materials compared revealed differences in their structural properties, reflected in their spectroscopic characteristics. The most intense luminescence was recorded for BaLuF{sub 5} based materials which exhibited upconversion also as water colloids. - Highlights: • BaREF{sub 5} nanomaterials (RE = Y, Gd or Lu) were synthesized by hydrothermal method. • Upconversion in BaREF{sub 5}:Yb{sup 3+}, Ln{sup 3+} (Ln = Ho, Er, Tm) nanocrystals was compared. • Mechanism of upconversion was analysed.

  18. Half Life Measurements in {sup 155}Gd

    Energy Technology Data Exchange (ETDEWEB)

    Malmskog, S.G.

    1966-08-15

    In the literature there exists a definite difference for the half life of the 86.5 keV level in Gd depending on whether {sup 155}Eu or {sup 155}Tb sources have been used. Using a good energy resolution electron-electron coincidence spectrometer and a {sup 155}Eu source, a half life of 6.48 {+-} 0.26 nsec was obtained for the 86.5 keV level. This is in agreement with the values previously measured with {sup 155}Tb sources. The half life of the 105.4 keV level was measured to be 1.12 {+-} 0.05 nsec.

  19. Half Life Measurements in 155Gd

    International Nuclear Information System (INIS)

    Malmskog, S.G.

    1966-08-01

    In the literature there exists a definite difference for the half life of the 86.5 keV level in Gd depending on whether 155 Eu or 155 Tb sources have been used. Using a good energy resolution electron-electron coincidence spectrometer and a 155 Eu source, a half life of 6.48 ± 0.26 nsec was obtained for the 86.5 keV level. This is in agreement with the values previously measured with 155 Tb sources. The half life of the 105.4 keV level was measured to be 1.12 ± 0.05 nsec

  20. Angle-Resolved Photoemission Study of the Evolution of Band Structure And Charge Density Wave Properties in Rte (3) (R=Y, La, Ce, Sm, Gd, Tb, And Dy)

    Energy Technology Data Exchange (ETDEWEB)

    Brouet, V.; Yang, W.L.; Zhou, X.J.; Hussain, Z.; Moore, R.G.; He, R.; Lu, D.H.; Shen, Z.X.; Laverock, J.; Dugdale, S.B.; Ru, N.; Fisher, I.R.

    2009-05-12

    We present a detailed angle-resolved photoemission spectroscopy (ARPES) investigation of the RTe{sub 3} family, which sets this system as an ideal 'textbook' example for the formation of a nesting driven charge density wave (CDW). This family indeed exhibits the full range of phenomena that can be associated to CDW instabilities, from the opening of large gaps on the best nested parts of Fermi surface (up to 0.4 eV), to the existence of residual metallic pockets. ARPES is the best suited technique to characterize these features, thanks to its unique ability to resolve the electronic structure in k space. An additional advantage of RTe{sub 3} is that the band structure can be very accurately described by a simple two dimensional tight-binding (TB) model, which allows one to understand and easily reproduce many characteristics of the CDW. In this paper, we first establish the main features of the electronic structure by comparing our ARPES measurements with the linear muffin-tin orbital band calculations. We use this to define the validity and limits of the TB model. We then present a complete description of the CDW properties and of their strong evolution as a function of R. Using simple models, we are able to reproduce perfectly the evolution of gaps in k space, the evolution of the CDW wave vector with R, and the shape of the residual metallic pockets. Finally, we give an estimation of the CDW interaction parameters and find that the change in the electronic density of states n(E{sub F}), due to lattice expansion when different R ions are inserted, has the correct order of magnitude to explain the evolution of the CDW properties.

  1. Study of quantitative analysis of rare earth elements (Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) in soil samples by inductively couple plasma mass spectrometry

    International Nuclear Information System (INIS)

    Truong Duc Toan; Nguyen Giang; Vo Tran Quang Thai; Do Tam Nhan; Nguyen Le Anh; Nguyen Viet Duc; Luong Thi Tham; Truong Thi Phuong Mai

    2015-01-01

    Method for the determination of 16 rare earth elements (REEs) in soil samples without separating by inductively coupled plasma mass spectrometry (ICP-MS) has been studied at Dalat Nuclear Research Institute. The optimal conditions for ICP-MS NexION 300X with three modes: Standard, Collision (KED), and Reaction (DRC) have been studied on the Montana II soil reference material. The result analysis shows that: DRC mode only gives good analysis result for Sc, Y, La, Ce, Pr, Nd, Tm, Yb, and Lu; Standard mode exhibits good analysis results for all elements with error from 1.2 - 29.0% and KED mode is the best one with error less than 15%. The concentrations of elements in the soil samples of Cau Dat, Bao Loc, and Da Lat were determined, which concentrations of REEs in soil samples of Cau Dat are higher than that of the other areas in Lam Dong Province. (author)

  2. Testing for TB Infection

    Science.gov (United States)

    ... Studies Consortium Research Projects Publications TB Trials Consortium Study Descriptions Background Behavioral & Social Science Research Infection Control TB in Specific Populations African-American Community Stop TB in the African-American ...

  3. Studies of the energy transfer processes from Er3+ and Ho3+ to Nd3+, Tb3+ or Eu3+ in LiYF4 crystal and ZBLAN glass for the laser media optimization operating near 3μm region

    International Nuclear Information System (INIS)

    Jagosich, Fabio Henrique

    2006-01-01

    The energy transfer processes (ET) from the 4 I 13/2 ; 4 I 11/2 levels of Er 3+ and 5 I 6 levels of Ho 3+ ions in LiYF 4 (YLF) crystal and ZBLAN glass to Nd 3+ , Tb 3+ or Eu 3+ deactivators ions were studied. The micro parameters of these energy transfer processes were determined using the overlap integral method, and showed that Eu 3+ ion is the best deactivator of the first excited state of the Ho 3+ in YLF, and Nd 3+ is the best deactivator of the Er 3+ in YLF and ZBLAN materials. The 1.5 and 2.7μm emissions of Er 3+ and 2.1 and 2.9μm fluorescence of Ho 3+ were measured using short laser pulses excitations from a tunable OPO pumped 2w-Nd:YAG laser system. We proposed a criterion for discriminating the energy transfer processes assisted by excitation migration (diffusion or hopping) among donors. It was observed that diffusion model describes the ET process from the second excited state of the donor (Er 3+ or Ho 3+ ) independently of the C D-D /C D-A ratio, while the hopping model can describe the ET process involving the first excited state of donor. We proposed a modification of the hopping model in order to describe the experimental results for systems having C D-D /C D-A ≥ 10. Using the ET parameters, we determined that the best systems for laser action at 3μm are the Ho:Eu:YLF, Ho:Nd:YLF and Er:Nd:YLF systems. On the other hand, we found that Er 3+ doped (1.5 mol%) ZBLAN glasses, single and co-doped with Nd 3+ , Tb 3+ or Eu 3+ , do not show potential for laser action at 2.8μm. The up-conversion processes were studied in Er:YLF systems as a function of the Er 3+ concentration, and the excited state absorption (ESA) and up conversion by energy transfer (ETU) processes were discriminated using a time resolved fluorescence decays. It was observed that 980 nm is the most convenient wavelength for pumping the Er:YLF system for quasi cw laser operation at 2.8μm. The pump-probe technique was used to investigate the lifetime effects in Er:YLF system showing

  4. Tuberculosis Facts - Exposure to TB

    Science.gov (United States)

    Tuberculosis (TB) Facts Exposure to TB What is TB? “TB” is short for a disease called tuberculosis. TB is spread through the air from one ... Viral Hepatitis, STD, and TB Prevention Division of Tuberculosis Elimination

  5. Tuberculosis Facts - Testing for TB

    Science.gov (United States)

    Tuberculosis (TB) Facts Testing for TB What is TB? “TB” is short for a disease called tuberculosis. TB is spread through the air from one ... Viral Hepatitis, STD, and TB Prevention Division of Tuberculosis Elimination

  6. Multi-quasiparticle excitations in 145Tb

    International Nuclear Information System (INIS)

    Zheng Yong; Zhou Xiaohong; Zhang Yuhu; Liu Minliang; Guo Yingxiang; Lei Xiangguo; Kusakari, H.; Sugawara, M.

    2004-01-01

    High-spin states in 145 Tb have been populated using the 118 Sn( 32 S, 1p4n) reaction at a beam energy of 165 MeV. The level scheme of 145 Tb has been established for the first time. The level scheme shows characteristics of spherical or slightly oblate nucleus. Based on the systematic trends of the level structure in the neighboring N=80 isotones, the level structure in 145 Tb below 2 MeV excitation is well explained by coupling an h 11/2 valence proton to the even-even 144 Gd core. Above 2 MeV excitation, most of the yrast levels are interpreted with multi-quasiparticle shell-model configurations. (authors)

  7. Synthesis, structures, and luminescent properties of sodium rare-earth metal(III) chloride oxotellurates(IV), Na{sub 2}Ln{sub 3}Cl{sub 3}[TeO{sub 3}]{sub 4} (Ln = Sm, Eu, Gd, Tb, Dy, and Ho)

    Energy Technology Data Exchange (ETDEWEB)

    Charkin, Dmitri O.; Dorofeev, Sergey G.; Berdonosov, Peter S.; Dolgikh, Valery A. [Department of Chemistry, Lomonosov Moscow State University (Russian Federation); Zitzer, Sabine; Greiner, Stefan; Schleid, Thomas [Institut fuer Anorganische Chemie, Universitaet Stuttgart (Germany); Olenev, Andrei V. [Department of Chemistry, Lomonosov Moscow State University (Russian Federation); Sine Theta Ltd., Moscow (Russian Federation)

    2017-11-17

    Six sodium rare-earth metal(III) chloride oxotellurates(IV), Na{sub 2}Ln{sub 3}Cl{sub 3}[TeO{sub 3}]{sub 4}, isostructural to Na{sub 2}Y{sub 3}Cl{sub 3}[TeO{sub 3}]{sub 4}, were synthesized by flux techniques and characterized by single-crystal XRD. The compounds crystallize in the monoclinic space group C2/c with lattice constants a = 23.967(1), b = 5.6342(3), c = 16.952(1) Aa, β = 134.456(5) for Ln = Sm, a = 23.932(2), b = 5.6044(5), c = 17.134(1) Aa, β = 135.151(6) for Ln = Eu, a = 23.928(1), b = 5.5928(1), c = 17.1133(8) Aa, β = 135.366(3) for Ln = Gd, a = 23.907(1), b = 5.569(3), c = 16.745(1) Aa, β = 134.205(3) for Ln = Tb, a = 23.870(1), b = 5.547(3), c = 16.665(1) Aa, β = 134.102(3) for Ln = Dy, and a = 23.814(1), b = 5.526(3), c = 16.626(1) Aa, β = 134.016(3) for Ln = Ho and Z = 4. Their crystal structure can be considered as a framework built of intergrowing Ln-O and Na-(O,Cl) slabs with channel walls decorated by tellurium atoms of [TeO{sub 3}]{sup 2-} groups. The luminescent properties of the new compounds due to the Ln{sup 3+} cations are described and discussed. We also discuss the crystal chemistry of various alkali-metal rare-earth metal(III) halide oxochalcogenates(IV). (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Find TB. Treat TB. Working together to eliminate TB.

    Centers for Disease Control (CDC) Podcasts

    2014-02-26

    In this podcast, Dr. Sundari Mase, Medical Team Lead in the Field Services and Evaluation Branch in the Division of Tuberculosis Elimination, discusses World TB Day and the 2014 theme.  Created: 2/26/2014 by National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention (NCHHSTP).   Date Released: 2/26/2014.

  9. The low-energy β(-) and electron emitter (161)Tb as an alternative to (177)Lu for targeted radionuclide therapy.

    Science.gov (United States)

    Lehenberger, Silvia; Barkhausen, Christoph; Cohrs, Susan; Fischer, Eliane; Grünberg, Jürgen; Hohn, Alexander; Köster, Ulli; Schibli, Roger; Türler, Andreas; Zhernosekov, Konstantin

    2011-08-01

    The low-energy β(-) emitter (161)Tb is very similar to (177)Lu with respect to half-life, beta energy and chemical properties. However, (161)Tb also emits a significant amount of conversion and Auger electrons. Greater therapeutic effect can therefore be expected in comparison to (177)Lu. It also emits low-energy photons that are useful for gamma camera imaging. The (160)Gd(n,γ)(161)Gd→(161)Tb production route was used to produce (161)Tb by neutron irradiation of massive (160)Gd targets (up to 40 mg) in nuclear reactors. A semiautomated procedure based on cation exchange chromatography was developed and applied to isolate no carrier added (n.c.a.) (161)Tb from the bulk of the (160)Gd target and from its stable decay product (161)Dy. (161)Tb was used for radiolabeling DOTA-Tyr3-octreotate; the radiolabeling profile was compared to the commercially available n.c.a. (177)Lu. A (161)Tb Derenzo phantom was imaged using a small-animal single-photon emission computed tomography camera. Up to 15 GBq of (161)Tb was produced by long-term irradiation of Gd targets. Using a cation exchange resin, we obtained 80%-90% of the available (161)Tb with high specific activity, radionuclide and chemical purity and in quantities sufficient for therapeutic applications. The (161)Tb obtained was of the quality required to prepare (161)Tb-DOTA-Tyr3-octreotate. We were able to produce (161)Tb in n.c.a. form by irradiating highly enriched (160)Gd targets; it can be obtained in the quantity and quality required for the preparation of (161)Tb-labeled therapeutic agents. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. Mycobacteria and TB

    National Research Council Canada - National Science Library

    Kaufmann, S. H. E. (Stephan H. E.); Hahn, Helmut

    2003-01-01

    .... Scientists investigating the epidemiology, immunology and molecular biology of TB or engaged in vaccine and drug development as well as physicians and social workers treating TB patients will benefit...

  11. 155Gd Moessbauer spectroscopic investigation of 3d-4f and 4f-4f' dinuclear complexes containing Gd (III)

    International Nuclear Information System (INIS)

    Ayabe, T.; Takahashi, M.; Takeda, M.; Costes, J.P.

    2006-01-01

    155 Gd Moessbauer spectra for dinuclear complexes of Gd 3+ and lanthanide (III) ion having a Schiff base ligand (L) derived from tren and 3-ethoxysalicylaldehyde were measured at 12 K. Moessbauer spectra of these complexes showed quadrupole split spectra. Two kinds of isomer shift values are observed; i.e, δ=0.57 - 0.60 mm s -1 for LGdLn' (Ln' = Ce, Nd, Eu, Gd) and δ=0.64-0.66 mm s -1 for LLnGd (Ln=Dy, Er, Yb). The former values are very close to those of nitrogen-containing Gd (III) complexes (δ=0.59-0.62 mm s -1 ) such as edta and cyano-bridged complexes. The latter values are on the other hand, in the range of oxygen-coordinating Gd (III) complexes (δ=0.64-0.65 mm s -1 ) such as polyethylene glycol Gd (III) complexes. 155 Gd Moessbauer spectra for LLnLn' complexes indicate that the smaller lanthanide ion Ln is in the N 4 O 3 site and the larger ion Ln' in the O 10 site. (author)

  12. Treatment: Latent TB Infection (LTBI) and TB Disease

    Science.gov (United States)

    ... Studies Consortium Research Projects Publications TB Trials Consortium Study Descriptions Background Behavioral & Social Science Research Infection Control TB in Specific Populations African-American Community Stop TB in the African-American ...

  13. TB in Captive Elephants

    Centers for Disease Control (CDC) Podcasts

    2017-04-27

    Dr. Barry Kreiswirth, founding director of the Public Health Research Institute, TB Center, at Rutgers University, discusses TB in three captive elephants.  Created: 4/27/2017 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 4/27/2017.

  14. Questions and Answers about TB

    Science.gov (United States)

    ... Studies Consortium Research Projects Publications TB Trials Consortium Study Descriptions Background Behavioral & Social Science Research Infection Control TB in Specific Populations African-American Community Stop TB in the African-American ...

  15. Studies of the energy transfer processes from Er{sup 3+} and Ho{sup 3+} to Nd{sup 3+}, Tb{sup 3+} or Eu{sup 3+} in LiYF{sub 4} crystal and ZBLAN glass for the laser media optimization operating near 3{mu}m region; Estudos dos processos de transferencia de energia dos ions de Er{sup 3+} e Ho{sup 3+} para os ions de Nd{sup 3+}, Tb{sup 3+} e Eu{sup 3+} no cristal de LiYF{sub 4} e no vidro ZBLAN para a otimizacao de meios laser ativos que operam na regiao de 3{mu}m

    Energy Technology Data Exchange (ETDEWEB)

    Jagosich, Fabio Henrique

    2006-07-01

    The energy transfer processes (ET) from the {sup 4}I{sub 13/2}; {sup 4}I{sub 11/2} levels of Er{sup 3+} and {sup 5}I{sub 6} levels of Ho{sup 3+} ions in LiYF{sub 4} (YLF) crystal and ZBLAN glass to Nd{sup 3+}, Tb{sup 3+} or Eu{sup 3+} deactivators ions were studied. The micro parameters of these energy transfer processes were determined using the overlap integral method, and showed that Eu{sup 3+} ion is the best deactivator of the first excited state of the Ho{sup 3+} in YLF, and Nd{sup 3+} is the best deactivator of the Er{sup 3+} in YLF and ZBLAN materials. The 1.5 and 2.7{mu}m emissions of Er{sup 3+} and 2.1 and 2.9{mu}m fluorescence of Ho{sup 3+} were measured using short laser pulses excitations from a tunable OPO pumped 2w-Nd:YAG laser system. We proposed a criterion for discriminating the energy transfer processes assisted by excitation migration (diffusion or hopping) among donors. It was observed that diffusion model describes the ET process from the second excited state of the donor (Er{sup 3+} or Ho{sup 3+}) independently of the C{sub D-D}/C{sub D-A} ratio, while the hopping model can describe the ET process involving the first excited state of donor. We proposed a modification of the hopping model in order to describe the experimental results for systems having C{sub D-D}/C{sub D-A} {>=} 10. Using the ET parameters, we determined that the best systems for laser action at 3{mu}m are the Ho:Eu:YLF, Ho:Nd:YLF and Er:Nd:YLF systems. On the other hand, we found that Er{sup 3+} doped (1.5 mol%) ZBLAN glasses, single and co-doped with Nd{sup 3+}, Tb{sup 3+} or Eu{sup 3+}, do not show potential for laser action at 2.8{mu}m. The up-conversion processes were studied in Er:YLF systems as a function of the Er{sup 3+} concentration, and the excited state absorption (ESA) and up conversion by energy transfer (ETU) processes were discriminated using a time resolved fluorescence decays. It was observed that 980 nm is the most convenient wavelength for pumping the Er

  16. Tuberculosis Facts - TB and HIV/AIDS

    Science.gov (United States)

    Tuberculosis (TB) Facts TB and HIV/AIDS What is TB? “TB” is short for a disease called tuberculosis. TB is spread through the air from one ... Viral Hepatitis, STD, and TB Prevention Division of Tuberculosis Elimination

  17. Tuberculosis (TB): Treatment

    Science.gov (United States)

    ... Education & Training Home Conditions Tuberculosis (TB) Tuberculosis: Treatment Tuberculosis: Treatment Make an Appointment Refer a Patient Ask ... or bones is treated longer. NEXT: Preventive Treatment Tuberculosis: Diagnosis Tuberculosis: History Clinical Trials For more than ...

  18. HIV and Tuberculosis (TB)

    Science.gov (United States)

    ... AIDS Drugs Clinical Trials Apps skip to content HIV and Opportunistic Infections, Coinfections, and Conditions Home Understanding ... 4 p.m. ET) Send us an email HIV and Tuberculosis (TB) Last Reviewed: July 26, 2017 ...

  19. Synthesis and luminescence properties of BaTiO3: RE (RE= Gd 3 ...

    Indian Academy of Sciences (India)

    Gd3+, Dy3+, Tb3+ and Lu3+ doped BaTiO3-based phosphors were synthesized with modified solidstate technique at 1000 °C. The optimization of reaction conditions were carried out by thermogravimetry and differential thermal analysis methods (DTA/TG). The reaction products obtained in an air atmosphere were ...

  20. Near infrared emission of TbAG:Ce{sup 3+},Yb{sup 3+} phosphor for solar cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Meshram, N. D., E-mail: meshramnileshsd@gmail.com [Shri. Mathuradas Mohota College of Science, Sakkardara Square, Nagpur-440009 (India); Yadav, P. J., E-mail: yadav.pooja75@yahoo.in [Department of Electronics, Nagpur University campus, Nagpur-440010 (India); Pathak, A. A., E-mail: aapathak@yahoo.com [National power Training Institute, South ambazari road, Nagpur-440022 (India); Joshi, C. P., E-mail: charusheela-4253@yahoo.co.in [Ramdeobaba College of Engineering and Management, Katol road, Gittikhadan Nagpur-440012 (India); Moharil, S. V., E-mail: svmoharil@yahoo.com [Department of Physics, Nagpur University campus, Nagpur-440010 (India)

    2016-05-06

    Luminescent materials doped with rare earth ions are used for many devices such as optical amplifiers in telecommunication, phosphors for white light emitting diodes (LEDs), displays, and so on. Recently, they also have attracted a great interest for photovoltaic applications to improve solar cell efficiency by modifying solar spectrum. Crystal silicon (c-Si) solar cells most effectively convert photons of energy close to the semiconductor band gap. The mis-match between the incident solar spectrum and the spectral response of solar cells is one of the main reasons to limit the cell efficiency. The efficiency limit of the c-Si has been estimated to be 29% by Shockley and Queisser. However, this limit is estimated to be improved up to 38.4% by modifying the solar spectrum by a quantum cutting (down converting) phosphor which converts one photon of high energy into two photons of lower energy. The phenomenon such as the quantum cutting or the down conversion of rare earth ions have been investigated since Dexter reported the possibility of a luminescent quantum yield greater than unity in 1957. In the past, the quantum cutting from a vacuum ultraviolet photon to visible photons for Pr{sup 3+}, Gd{sup 3+},Gd{sup 3+}–Eu{sup 3+}, and Er{sup 3+}–Tb{sup 3+} had been studied. Recently, a new quantum cutting phenomenon from visible photon shorter than 500 nm to two infrared photons for Tb{sup 3+}–Yb{sup 3+}, Pr{sup 3+}–Yb{sup 3+}, and Tm{sup 3+}–Yb{sup 3+} has been reported. The Yb{sup 3+} ion is suitable as an acceptor and emitter because luminescent quantum efficiency of Yb{sup 3+} is close to 100% and the energy of the only excited level of Yb{sup 3+} (1.2 eV) is roughly in accordance with the band gap of Si (1.1 eV). In addition, the Ce{sup 3+}-doped Tb{sub 3}Al{sub 5}O{sub 12} (TbAG), used as a phosphor for white LED, has broad absorption bands in the range of 300–500 nm due to strong ligand field and high luminescent quantum efficiency. Therefore, the

  1. Luminescence properties of barium--gadolinium-titanate ceramics doped with rare-earth ions (Eu3+ and Tb3+).

    Science.gov (United States)

    Hemasundara Raju, S; Muni Sudhakar, B; Sudhakar Reddy, B; Dhoble, S J; Thyagarajan, K; Nageswara Raju, C

    2014-11-01

    Barium-gadolinium-titanate (BaGd2 Ti4 O12) powder ceramics doped with rare-earth ions (Eu(3+) and Tb(3+)) were synthesized by a solid-state reaction method. From the X-ray diffraction spectrum, it was observed that Eu(3+) and Tb(3+):BaGd2 Ti4 O12 powder ceramics are crystallized in the form of an orthorhombic structure. Scanning electron microscopy image shows that the particles are agglomerated and the particle size is about 200 nm. Eu(3+) - and Tb(3+) -doped BaGd2 Ti4 O12 powder ceramics were examined by energy dispersive X-ray analysis, Fourier transform infrared spectroscopy, photoluminescence and thermoluminescence (TL) spectra. Emission spectra of Eu(3+)-doped BaGd2 Ti4 O12 powder ceramics showed bright red emission at 613 nm ((5)D0 →(7)F2) with an excitation wavelength λ(exci)  = 408 nm ((7)F0 → (5)D3) and Tb(3+):BaGd2 Ti4 O12 ceramic powder has shown green emission at 534 nm ((5)D4 → (7)F5) with an excitation wavelength λ(exci)  = 331 nm (((7)F6 → (5)D1). TL spectra show that Eu(3+) and Tb(3+) ions affect TL sensitivity. Copyright © 2014 John Wiley & Sons, Ltd.

  2. Luminescence of Sm, Eu and Tb in compounds with heptafluoroheptanedione and possibility to use in analysis

    International Nuclear Information System (INIS)

    Kononenko, L.I.; Kravchenko, T.B.; Bel'tyukova, S.V.; Kuz'min, V.E.; Suprinovich, E.S.

    1980-01-01

    Proposed is heptafluoroheptanedione - 2.4 (HFHD) as a luminescent reagent on Eu 3+ , Sm 3+ , Tb 3+ . Complex formation of rare earths with HFHD approaches maximum at 7.5-8.5 pH. The formed complex compounds of rare earths with HFHD are well extracted from aqueous solutions by a number of organic solvents, Isub(lum) of the extracts is the same as that of the complex in aqueous-ethanol solution. The given method permits to determine Eu, Sm, Tb microquantities in Y, La, Sm, Gd, Tb, Yb and Lu oxides. Variation coefficient does not exceed 6.5 %

  3. Study of Gd lattices

    International Nuclear Information System (INIS)

    Vidovsky, I.; Kereszturi, A.

    1991-11-01

    The results of experiments and calculations on Gd lattices are presented, and a comparison of experimental and calculational data is given. This latter can be divided into four groups. The first belongs to the comparison of criticality parameters, the second group is related with the comparison of 2D distributions, the third one relates the comparison of intra-macrocell distributions, whereas the fourth group is devoted for the comparison of spectral parameters. For comparison, the computer code RFIT based on strict statistical criteria has been used. The calculated and measured results agree, in most cases, sufficiently. (R.P.) 11 refs.; 13 figs.; 9 tabs

  4. Tuberculosis Facts - You Can Prevent TB

    Science.gov (United States)

    Tuberculosis (TB) Facts You Can Prevent TB What is TB? “TB” is short for a disease called tuberculosis. TB is spread through the air from one ... Viral Hepatitis, STD, and TB Prevention Division of Tuberculosis Elimination TB Facts: You Can Prevent TB What ...

  5. Tuberculosis Facts - TB Can Be Treated

    Science.gov (United States)

    Tuberculosis (TB) Facts TB Can Be Treated What is TB? “TB” is short for a disease called tuberculosis. TB is spread through the air from one ... Viral Hepatitis, STD, and TB Prevention Division of Tuberculosis Elimination Page 1 of 2 TB Facts: TB ...

  6. The temperature dependence studies of rare-earth (Dy.sup.3+./sup., Sm.sup.3+./sup., Eu.sup.3+./sup. and Tb.sup.3+./sup.) activated Gd.sub.3./sub.Ga.sub.3./sub.Al.sub.2./sub.O.sub.12./sub. garnet single crystals

    Czech Academy of Sciences Publication Activity Database

    Bartosiewicz, Karol; Babin, Vladimir; Beitlerová, Alena; Boháček, Pavel; Jurek, Karel; Nikl, Martin

    2017-01-01

    Roč. 189, Sep (2017), s. 126-139 ISSN 0022-2313 R&D Projects: GA ČR GA16-15569S EU Projects: European Commission(XE) 316906 - LUMINET Institutional support: RVO:68378271 Keywords : Gd3Ga3Al2O12 * rare earth dopants * energy transfer * thermal quenching * single crystal Subject RIV: BH - Optics, Masers, Lasers OBOR OECD: Optics (including laser optics and quantum optics) Impact factor: 2.686, year: 2016

  7. Multicolor Tunable Luminescence Based on Tb3+/Eu3+ Doping through a Facile Hydrothermal Route.

    Science.gov (United States)

    Wang, Chao; Zhou, Ting; Jiang, Jing; Geng, Huiyuan; Ning, Zhanglei; Lai, Xin; Bi, Jian; Gao, Daojiang

    2017-08-09

    Ln 3+ -doped fluoride is a far efficient material for realizing multicolor emission, which plays an important part in full-color displays, biolabeling, and MRI. However, studies on the multicolor tuning properties of Ln 3+ -doped fluoride are mainly concentrated on a complicated process using three or more dopants, and the principle of energy transfer mechanism is still unclear. Herein, multicolor tunable emission is successfully obtained only by codoping with Tb 3+ and Eu 3+ ions in β-NaGdF 4 submicrocrystals via a facile hydrothermal route. Our work reveals that various emission colors can be obtained and tuned from red, orange-red, pink, and blue-green to green under single excitation energy via codoping Tb 3+ and Eu 3+ with rationally changed Eu 3+ /Tb 3+ molar ratio due to the energy transfer between Tb 3+ and Eu 3+ ions in the β-NaGdF 4 host matrix. Meanwhile, the energy transfer mechanism in β-NaGdF 4 : x Eu 3+ /y Tb 3+ (x + y = 5 mol %) submicrocrystals is investigated. Our results evidence the potential of the dopants' distribution density as an effective way for analyzing energy transfer and multicolor-controlled mechanism in other rare earth fluoride luminescence materials. Discussions on the multicolor luminescence under a certain dopant concentration based on single host and wavelength excitation are essential toward the goal of the practical applications in the field of light display systems and optoelectronic devices.

  8. Crystal structure and magnetic properties of Tb-doped Ru-1222 ruthenocuprates

    International Nuclear Information System (INIS)

    Lee, H.K.; Kim, K.W.; Lee, M.S.; Kim, Y.I.

    2014-01-01

    The effects of Tb doping on the structural, superconducting, and magnetic properties of (Ru 0.9 Nb 0.1 )Sr 2 (Gd 1.34−x Tb x Ce 0.66 )Cu 2 O z and RuSr 2 (Eu 1.34−x Tb x Ce 0.66 )Cu 2 O z (x=0, 0.34) systems were investigated. It was found that Tb doping in both systems results in a significant suppression of superconductivity and an enhancement of the magnetic ordering temperature, as well as an enhancement of the weak-ferromagnetic component of field-cooled magnetization. The Rietveld refinements of the X-ray diffraction data at room temperature showed that both a and c lattice parameters decrease and the rotation angle of the RuO 6 octahedron around the crystallographic c-axis decreases by Tb doping in both systems. The superconducting and magnetic behaviors induced by the Tb doping are discussed in conjunction with the change in hole concentration and the local structural changes in the Ru sublattice induced by Tb doping. - Highlights: • Study on (Ru 0.9 Nb 0.1 )Sr 2 (Gd 1.34−x Tb x Ce 0.66 )Cu 2 O z and RuSr 2 (Eu 1.34−x Tb x Ce 0.66 )Cu 2 O z . • Tb doping enhances weak-ferromagnetic ordering and suppresses superconductivity. • We report correlations between magnetic properties and structural changes

  9. 111Cd PAC Study of Gd-Ni Intermetallic Compounds

    International Nuclear Information System (INIS)

    Presa, P. de la; Forker, M.

    2004-01-01

    This paper presents a perturbed angular correlation study of the magnetic and electric hyperfine interactions of 111 Cd on Gd sites of the Gd-Ni intermetallic compounds GdNi, GdNi 2 , GdNi 3 , Gd 2 Ni 7 , GdNi 5 and Gd 2 Ni 17 .

  10. TB or not TB?: a case of isolated testicular TB with scrotal involvement.

    LENUS (Irish Health Repository)

    Bhargava, A

    2009-06-01

    Despite the genitourinary tract being the most common site affected by extrapulmonary TB, isolated testicular TB remains a rare clinical entity. In patients with co-morbidities such as hepatic impairment, treatment proves a challenge, as first-line hepatotoxic pharmaceuticals are contraindicated. Here, we report a case of isolated testicular TB with scrotal involvement, on a background of hepatic dysfunction.

  11. Compensation scheme for online neutron detection using a Gd-covered CdZnTe sensor

    Energy Technology Data Exchange (ETDEWEB)

    Dumazert, Jonathan, E-mail: jonathan.dumazert@cea.fr; Coulon, Romain; Kondrasovs, Vladimir; Boudergui, Karim

    2017-06-11

    The development of portable and personal neutron dosimeters requires compact and efficient radiation sensors. Gd-157, Gd-155 and Cd-113 nuclei present the highest cross-sections for thermal neutron capture among natural isotopes. In order to allow for the exploitation of the low and medium-energy radiative signature of the said captures, the contribution of gamma background radiation, falling into the same energy range, needs to be cancelled out. This paper introduces a thermal neutron detector based on a twin-dense semiconductor scheme. The neutron-sensitive channel takes the form of a Gd-covered CdZnTe crystal, a high density and effective atomic number detection medium. The background compensation will be carried out by means of an identical CdZnTe sensor with a Tb cover. The setting of a hypothesis test aims at discriminating the signal generated by the signature of thermal neutron captures in Gd from statistical fluctuations over the compensation of both independent channels. The measurement campaign conducted with an integrated single-channel chain and two metal Gd and Tb covers, under Cs-137 and Cf-252 irradiations, provides first quantitative results on gamma-rejection and neutron sensitivity. The described study of concept gives grounds for a portable, online-compatible device, operable in conventional to controlled environments.

  12. Neutron scattering study on R2PdSi3 (R=Ho,Er,Tm) compounds

    International Nuclear Information System (INIS)

    Tang, Fei

    2010-01-01

    Previous studies on the family of inter-metallic rare-earth compounds R 2 PdSi 3 revealed multifaceted magnetic properties, for instance, spin-glass like behavior. Experimental observations include: Signs of a crystallographic superstructure, complicated magnetic structures both in zero field and in applied magnetic fields as well as a generic phase in applied fields for compounds in the series with the heavy rare-earths R=Gd, Tb, Dy, Ho, Er and Tm. This thesis expands the studies on the magnetic properties of R 2 PdSi 3 employing mainly neutron scattering on single crystals with the focus on the compounds with R=Ho, Er and Tm. A detailed analysis of the crystallographic superstructure using modulation wave approach and group theory is presented. The resulting structure implies the existence of two different rare-earth sites with reduced symmetry and an arrangement of the different sites according to sequences as determined by the superstructure. It is shown that the reduced symmetry of the rare-earth sites is explicitly observed in the energy spectra of inelastic neutron scattering. The results on the magnetic structures and excitations are shown and discussed in the framework of the superstructure model. Specifically the generic phase in applied fields is interpreted as a direct consequence of the crystallographic superstructure. It is rather unusual that a crystallographic superstructure is playing such a decisive, and through the field dependence also tunable role in determining the magnetic properties as observed in R 2 PdSi 3 . The mediating interactions between the crystallographic part and the magnetic part of the system are discussed. (orig.)

  13. Induction of ER stress in macrophages of tuberculosis granulomas.

    Directory of Open Access Journals (Sweden)

    Tracie A Seimon

    2010-09-01

    Full Text Available The endoplasmic reticulum (ER stress pathway known as the Unfolded Protein Response (UPR is an adaptive survival pathway that protects cells from the buildup of misfolded proteins, but under certain circumstances it can lead to apoptosis. ER stress has been causally associated with macrophage apoptosis in advanced atherosclerosis of mice and humans. Because atherosclerosis shares certain features with tuberculosis (TB with regard to lesional macrophage accumulation, foam cell formation, and apoptosis, we investigated if the ER stress pathway is activated during TB infection.Here we show that ER stress markers such as C/EBP homologous protein (CHOP; also known as GADD153, phosphorylated inositol-requiring enzyme 1 alpha (Ire1α and eukaryotic initiation factor 2 alpha (eIF2α, and activating transcription factor 3 (ATF3 are expressed in macrophage-rich areas of granulomas in lungs of mice infected with virulent Mycobacterium tuberculosis (Mtb. These areas were also positive for numerous apoptotic cells as assayed by TUNEL. Microarray analysis of human caseous TB granulomas isolated by laser capture microdissection reveal that 73% of genes involved in the UPR are upregulated at the mRNA transcript level. The expression of two ER stress markers, ATF3 and CHOP, were also increased in macrophages of human TB granulomas when assayed by immunohistochemistry. CHOP has been causally associated with ER stress-induced macrophage apoptosis. We found that apoptosis was more abundant in granulomas as compared to non-granulomatous tissue isolated from patients with pulmonary TB, and apoptosis correlated with CHOP expression in areas surrounding the centralized areas of caseation.In summary, ER stress is induced in macrophages of TB granulomas in areas where apoptotic cells accumulate in mice and humans. Although macrophage apoptosis is generally thought to be beneficial in initially protecting the host from Mtb infection, death of infected macrophages in

  14. Digital health for the End TB Strategy: developing priority products and making them work.

    Science.gov (United States)

    Falzon, Dennis; Timimi, Hazim; Kurosinski, Pascal; Migliori, Giovanni Battista; Van Gemert, Wayne; Denkinger, Claudia; Isaacs, Chris; Story, Alistair; Garfein, Richard S; do Valle Bastos, Luis Gustavo; Yassin, Mohammed A; Rusovich, Valiantsin; Skrahina, Alena; Van Hoi, Le; Broger, Tobias; Abubakar, Ibrahim; Hayward, Andrew; Thomas, Bruce V; Temesgen, Zelalem; Quraishi, Subhi; von Delft, Dalene; Jaramillo, Ernesto; Weyer, Karin; Raviglione, Mario C

    2016-07-01

    In 2014, the World Health Organization (WHO) developed the End TB Strategy in response to a World Health Assembly Resolution requesting Member States to end the worldwide epidemic of tuberculosis (TB) by 2035. For the strategy's objectives to be realised, the next 20 years will need novel solutions to address the challenges posed by TB to health professionals, and to affected people and communities. Information and communication technology presents opportunities for innovative approaches to support TB efforts in patient care, surveillance, programme management and electronic learning. The effective application of digital health products at a large scale and their continued development need the engagement of TB patients and their caregivers, innovators, funders, policy-makers, advocacy groups, and affected communities.In April 2015, WHO established its Global Task Force on Digital Health for TB to advocate and support the development of digital health innovations in global efforts to improve TB care and prevention. We outline the group's approach to stewarding this process in alignment with the three pillars of the End TB Strategy. The supplementary material of this article includes target product profiles, as developed by early 2016, defining nine priority digital health concepts and products that are strategically positioned to enhance TB action at the country level. The content of this work is ©the authors or their employers. Design and branding are ©ERS 2016.

  15. Triple energy transfer and color tuning in Tb3+ and Eu3+-coactivated apatite-type gadolinium-containing phosphors

    Science.gov (United States)

    Guo, Ning; Liang, Qimeng; Li, Shuo; Ouyang, Ruizhuo; Lü, Wei

    2017-11-01

    A family of apatite-type fluorophosphate phosphors with general formula Sr3Gd(1-m-n)Na(PO4)3F:mTb3+,nEu3+ (SGN:mTb3+,nEu3+) have been synthesized via the high-temperature solid-state reaction method. Triple energy transfer processes from Gd3+ in the host to both Tb3+ and Eu3+, as well as from Tb3+ to Eu3+ have been verified by the photoluminescence spectra. Under the excitation of UV light, both green line from the transitions of Tb3+ and red line origin from the transitions of Eu3+ have been simultaneously observed in a single phase phosphor, which makes a promise for tunable color emissions from yellowish-green through yellow and ultimately to reddish-orange by simply adjusting the Eu3+ content (n) in SGN:0.20Tb3+,nEu3+ phosphors. Additionally, the energy transfer from the Tb3+ to the Eu3+ ions has been demonstrated to be a resonant type via a quadrupole-quadrupole mechanism based on the Dexter's theoretical model, and the energy transfer efficiency increases with an increase in Eu3+ concentration.

  16. Difference Between Latent TB Infection and Active TB Disease

    Science.gov (United States)

    ... ATS) and CDC. Diagnostic standards and classification of tuberculosis in adults and children. (PDF) Am J Respir Crit Care Med 2000 ; 161. http: / / ajrccm. atsjournals. org/ cgi/ content/ full/ 161/ 4/ 1376 2. ... Tuberculosis (MDR TB) . http: / / www. cdc. gov/ tb/ publications/ ...

  17. Hvem er vi? Hvem er de?

    DEFF Research Database (Denmark)

    Kryger, Niels

    2016-01-01

    Kommentaren tager afsæt i initiativer i de pædagogiske faglige foreninger i Europa EERA) og i Norden (NERA) og argumenterer for at det er forpligtelse for os som nordiske og europæiske pædagogiske forskere at gå op imod de stadigt mere ekskluderende vi-konstruktioner, som er blevet formuleret i f...

  18. Synthesis and luminescence properties of BaTiO3:RE (RE = Gd3+, Dy3+, Th3+, Lu3+) phosphors

    International Nuclear Information System (INIS)

    Korkmaz, Esra; Kalaycioglu, Nilgun Ozpozan

    2012-01-01

    Gd 3+ , Dy 3+ , Tb 3+ and Lu 3+ doped BaTiO 3 -based phosphors were synthesized with modified solid-state technique at 1000 deg C. The optimization of reaction conditions were carried out by thermogravimetry and differential thermal analysis methods (DTA/TG). The reaction products obtained in an air atmosphere were characterized by X-ray powder diffraction (XRD). Surface and elemental analyses were performed by using an SEM instrument. The excitation and emission spectra were recorded by photoluminescence spectrophotometer (PL). The thermoluminescence (TL) properties of BaTiO 3 samples doped with Gd 3+ , Dy 3+ , Tb 3+ , Lu 3+ were investigated. (author)

  19. X-ray excited photoluminescence near the giant resonance in solid-solution Gd1-xTbxOCl nanocrystals and their retention upon solvothermal topotactic transformation to Gd1-xTbxF3

    Science.gov (United States)

    Waetzig, Gregory R.; Horrocks, Gregory A.; Jude, Joshua W.; Zuin, Lucia; Banerjee, Sarbajit

    2015-12-01

    Design rules for X-ray phosphors are much less established as compared to their optically stimulated counterparts owing to the absence of a detailed understanding of sensitization mechanisms, activation pathways and recombination channels upon high-energy excitation. Here, we demonstrate a pronounced modulation of the X-ray excited photoluminescence of Tb3+ centers upon excitation in proximity to the giant resonance of the host Gd3+ ions in solid-solution Gd1-xTbxOCl nanocrystals prepared by a non-hydrolytic cross-coupling method. The strong suppression of X-ray excited optical luminescence at the giant resonance suggests a change in mechanism from multiple exciton generation to single thermal exciton formation and Auger decay processes. The solid-solution Gd1-xTbxOCl nanocrystals are further topotactically transformed with retention of a nine-coordinated cation environment to solid-solution Gd1-xTbxF3 nanocrystals upon solvothermal treatment with XeF2. The metastable hexagonal phase of GdF3 can be stabilized at room temperature through this topotactic approach and is transformed subsequently to the orthorhombic phase. The fluoride nanocrystals indicate an analogous but blue-shifted modulation of the X-ray excited optical luminescence of the Tb3+ centers upon X-ray excitation near the giant resonance of the host Gd3+ ions.Design rules for X-ray phosphors are much less established as compared to their optically stimulated counterparts owing to the absence of a detailed understanding of sensitization mechanisms, activation pathways and recombination channels upon high-energy excitation. Here, we demonstrate a pronounced modulation of the X-ray excited photoluminescence of Tb3+ centers upon excitation in proximity to the giant resonance of the host Gd3+ ions in solid-solution Gd1-xTbxOCl nanocrystals prepared by a non-hydrolytic cross-coupling method. The strong suppression of X-ray excited optical luminescence at the giant resonance suggests a change in mechanism

  20. Magnetic properties of Gd intermetallics

    Science.gov (United States)

    Petit, L.; Szotek, Z.; Jackson, J.; Lüders, M.; Paudyal, D.; Mudryk, Y.; Pecharsky, V.; Gschneidner, K. A.; Staunton, J. B.

    2018-02-01

    Using first-principles calculations, based on disordered local moment theory, combined with the self-interaction corrected local spin density approximation, we study magnetic interactions in GdX intermetallics for X = Cu, Zn, Ga, Cd, and Mg. Our predicted magnetic orders and ordering temperatures both at zero and other pressures agree well with experiments including the large increase in the Curie temperature of GdCd under pressure that is shown by our own experimental measurements. From our results it emerges that the Ruderman-Kittel-Kasuya-Yosida interaction on its own can not explain the observed behaviour under pressure, and that the magnetic ordering mechanism is strongly influenced by the occupations of both Gd and anion d-bands.

  1. Ideologi er noget bras

    DEFF Research Database (Denmark)

    Hansen, Brian Benjamin; Jøker Bjerre, Henrik

    medieområdet kan dette skifte betragtes som den endelige sejr for den post-ideologiske konsensus, der går ud fra, at der ikke mere er behov for politisk diskussion, og at vi aldrig mere skal indlade os på farlige politiske eksperimenter. Ideologi er noget bras, sagde jo allerede Poul Schlüter. Med inspiration......, ideologiske ramme for vore liv. Ideologi er noget bras, men bras er også ideologi....

  2. Puf er plat

    DEFF Research Database (Denmark)

    Hansen, Pelle Guldborg; Zeller, Clara

    2015-01-01

    Der er stort set ingen, der har fattet, hvad nudging egentlig er. Et nudge er nemlig hverken ”et lille blidt skub”, eller ”en helt ny videnskabelig metode [der] kan ændre vores adfærd, uden vi opdager det - og uden det koster os noget”, ligesom det heller ikke er ”en måde at friste kunder til at ...

  3. Cybermagt er spoilermagt

    DEFF Research Database (Denmark)

    Nyemann, Dorthe Bach

    Cybermagt er spoilermagt. Det er overskriften på denne rapport, hvis hovedformål er at indkredse, hvilken rolle magt i cyberspace spiller for forholdet mellem stater. Rapporten undersøger cybermagtens centrale betydning for den øgede destabilisering af internationale relationer, mens den samtidig...... cyberspace via fælles initiativer....

  4. Man er aldrig alene

    DEFF Research Database (Denmark)

    Hoffmeyer, Jesper

    2013-01-01

    Nu ved vi, at der er mange slags DNA i vores krop, og at samarbejdet mellem de organismer, som bærer alt dette DNA, er essentielt for vores overlevelse" … "Kroppen er en slags økosystem, hvor alle slags samarbejde hen ad vejen bliver afprøvet"...

  5. Er alt design?

    DEFF Research Database (Denmark)

    Michelsen, Anders Ib; Engholm, Ida

    2016-01-01

    Design er et ord med mange betydninger. Hvad enten design er det, der kommer ud af en shoppingtur, om det indgår i et dannelsesbegreb, hvor den kultiverede og ”gode stol” har sin plads, er en uddannelse med forskning underneden eller en strategisk indsats for velfærdssamfundets forvandling til et...

  6. TB in Children in the United States

    Science.gov (United States)

    ... Studies Consortium Research Projects Publications TB Trials Consortium Study Descriptions Background Behavioral & Social Science Research Infection Control TB in Specific Populations African-American Community Stop TB in the African-American ...

  7. Extensively Drug-Resistant Tuberculosis (XDR TB)

    Science.gov (United States)

    ... Studies Consortium Research Projects Publications TB Trials Consortium Study Descriptions Background Behavioral & Social Science Research Infection Control TB in Specific Populations African-American Community Stop TB in the African-American ...

  8. Investigation of 155Gd, 157Gd and 159Gd nuclear deformation

    International Nuclear Information System (INIS)

    Araujo, J.M.R. de.

    1979-01-01

    Theoretical calculations of Transition Probabilities, Quadrupole Moments and Differential Inelastic Electron Cross-Sections for 155 Gd, 157 Gd and 159 Gd, for the first and second energy levels of the fundamental rotational band are presented. Electrons are described as distorted waves and the even-odd nuclei by means of the rotational model, with one particle strongly coupled to the even-even core. The intrinsic charge distribution of the core is deacribed by the Deformed Fermi Distribution and the extra particle by a single particle in a deformed harmonic potential produced by the core (Nilsson model). The inelastic electron cross-sections results show the possibility of a precise determination of deformation of the even-odd nuclei if measurements are carried. (author) [pt

  9. Growth of multiferroic Gd1-xYxMnO3 single crystals by optical floating zone technique

    International Nuclear Information System (INIS)

    Sarguna, R.M.; Ganesamoorthy, S.; Sridharan, V.; Subramanian, N.

    2014-01-01

    Rare earth manganites RMnO 3 with distorted perovskite structure are excellent multiferroic materials. The discovery of magnetic spin driven ferroelectricity in orthorhombic manganites (TbMnO 3 ) has sparked a surge in research into understanding the fundamental mechanism of multiferroic behavior. These systems fall under the category of type-2 multiferroics, the change of spatially modulated magnetic moment from sinusoidal to cycloidal gives rise to electric polarization. The magnetic structure depends upon the Mn-O-Mn bond angle. GdMnO 3 shows multiferroic properties only in the presence of applied magnetic field. When a magnetic field is applied along the b-axis, GdMnO 3 enters a ferroelectric state with an electric polarisation along the c-axis. By altering the Mn-O-Mn angle it is expected that GdMnO 3 will show multiferroic property even in the absence of magnetic field like TbMnO 3 . To alter the Mn-O-Mn bond angle GdMnO 3 was substituted with Y having lower ionic radius at Gd site. The effect of Y doping at the rare-earth site in GdMnO 3 investigated on polycrystalline samples of Gd 1-x Y x MnO 3 demonstrated a magneto-electric coupling in x=0.1-0.4. Single crystals are expected to give much amplified signal in respect of ferroelectric and magnetic properties. In this work we have grown Y substituted Gd 1-x Y x MnO 3 (x = 0.2, 0.3 and 0.4) by optical floating zone technique under different gas atmosphere. Growth rate of 1-2 mm/h yielded crack free crystals. Quality of the crystals was checked using Laue diffraction. Effect of growth rate and atmosphere pressure will be presented in this talk. (author)

  10. The regulation of ER export and Golgi retention of ST3Gal5 (GM3/GM4 synthase) and B4GalNAcT1 (GM2/GD2/GA2 synthase) by arginine/lysine-based motif adjacent to the transmembrane domain.

    Science.gov (United States)

    Uemura, Satoshi; Shishido, Fumi; Kashimura, Madoka; Inokuchi, Jin-ichi

    2015-12-01

    In the Golgi maturation model, the Golgi cisternae dynamically mature along a secretory pathway. In this dynamic process, glycosyltransferases are transported from the endoplasmic reticulum (ER) to the Golgi apparatus where they remain and function. The precise mechanism behind this maturation process remains unclear. We investigated two glycosyltransferases, ST3Gal5 (ST3G5) and B4GalNAcT1 (B4GN1), involved in ganglioside synthesis and examined their signal sequences for ER export and Golgi retention. Reports have suggested that the [R/K](X)[R/K] motif functions as an ER exporting signal; however, this signal sequence is insufficient in stably expressed, full-length ST3G5. Through further analysis, we have clarified that the (2)R(3)R(X)(5) (9)K(X)(3) (13)K sequence in ST3G5 is essential for ER export. We have named the sequence the R/K-based motif. On the other hand, for ER export of B4GN1, the homodimer formation in addition to the R/K-based motif is required for ER export suggesting the importance of unidentified lumenal side interaction. We found that ST3G5 R2A/R3A and K9A/K13A mutants localized not only in Golgi apparatus but also in endosomes. Furthermore, the amounts of mature type asparagine-linked (N)-glycans in ST3G5 R2A/R3A and K9A/K13A mutants were decreased compared with those in wild-type proteins, and the stability of the mutants was lower. These results suggest that the R/K-based motif is necessary for the Golgi retention of ST3G5 and that the retention is involved in the maturation of N-glycans and in stability. Thus, several basic amino acids located on the cytoplasmic tail of ST3G5 play important roles in both ER export and Golgi retention. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. Materials for ER Fluids

    Science.gov (United States)

    Bloodworth, Robert; Wendt, Eckhard

    Recent improvements in the physical understanding of ER fluids have led to the rational design of new ER materials with improved properties. This paper gives an overview of several recent developments in the formulation of ER fluids, concentrating on new particulate phases for ER dispersions. Examples of homogeneous ER fluids are also discussed. The trend leading to designed ER dispersions is demonstrated by a new class of electrorheological fluids based on non-aqueous polyurethane dispersions. The fluids exhibit an attractive combination of properties: low viscosity, high ER effect, and low conductivity. The dispersed phase consists of a specially developed polyurethane elastomer which solvates and stabilizes metal salts. The polymer network density influences the mobility of the dissolved ions, allowing a surprising degree of control over the ER effect. Properties such as the field strength dependence of the ER-effect, switching response, and conductivity of these fluids correlate directly with changes in the polymer structure. Electrorheological measurements in a couette viscometer (shear-mode) and in a model shock absorber (flow-mode) using a commercial polyurethane-based fluid show that the ER effect is also dependent upon the shearing geometry.

  12. Detectemos la TB. Tratemos la TB. Trabajemos juntos para eliminar la TB. (Find TB. Treat TB. Working together to eliminate TB.)

    Centers for Disease Control (CDC) Podcasts

    2014-02-26

    Este podcast trata sobre el Día Mundial de la Tuberculosis y el tema de los CDC para el año 2014.  Created: 2/26/2014 by National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention (NCHHSTP).   Date Released: 2/26/2014.

  13. Tuberculosis care among refugees arriving in Europe: a ERS/WHO Europe Region survey of current practices.

    Science.gov (United States)

    Dara, Masoud; Solovic, Ivan; Sotgiu, Giovanni; D'Ambrosio, Lia; Centis, Rosella; Tran, Richard; Goletti, Delia; Duarte, Raquel; Aliberti, Stefano; de Benedictis, Fernando Maria; Bothamley, Graham; Schaberg, Tom; Abubakar, Ibrahim; Teixeira, Vitor; Ward, Brian; Gratziou, Christina; Migliori, Giovanni Battista

    2016-09-01

    No evidence exists on tuberculosis (TB) and latent TB infection (LTBI) management policies among refugees in European countries.A questionnaire investigating screening and management practices among refugees was sent to 38 national TB programme representatives of low and intermediate TB incidence European countries/territories of the WHO European Region.Out of 36 responding countries, 31 (86.1%) reported screening for active TB, 19 for LTBI, and eight (22.2%) reporting outcomes of LTBI treatment. Screening for TB is based on algorithms including different combinations of symptom-based questionnaires, bacteriology and chest radiography and LTBI screening on different combinations of tuberculin skin test and interferon-γ release assays. In 22 (61.1%) countries, TB and LTBI screening are performed in refugee centres. In 22 (61.1%) countries, TB services are organised in collaboration with the private sector. 27 (75%) countries answered that screening for TB is performed as per national and international guidelines, while 19 (52.7%) gave the same answer with regards to LTBI screening. Infection control measures are inadequate in several of the countries surveyed.There is need for improved coordination of TB screening in Europe to implement the End TB Strategy and achieve TB elimination. Copyright ©ERS 2016.

  14. Deuteron induced Tb-155 production, a theranostic isotope for SPECT imaging and auger therapy.

    Science.gov (United States)

    Duchemin, C; Guertin, A; Haddad, F; Michel, N; Métivier, V

    2016-12-01

    Several terbium isotopes are suited for diagnosis or therapy in nuclear medicine. Tb-155 is of interest for SPECT imaging and/or Auger therapy. High radionuclide purity is mandatory for many applications in medicine. The quantification of the activity of the produced contaminants is therefore as important as that of the radionuclide of interest. The experiments performed at the ARRONAX cyclotron (Nantes, France), using the deuteron beam delivered up to 34MeV, provide an additional measurement of the excitation function of the Gd-nat(d,x)Tb-155 reaction and of the produced terbium and gadolinium contaminants. In this study, we investigate the achievable yield for each radionuclide produced in natural gadolinium as a function of the deuteron energy. Other reactions are discussed in order to define the production route that could provide Tb-155 with a high yield and a high radionuclide purity. This article aims to improve data for the Gd-nat(d,x) reaction and to optimize the irradiation conditions required to produce Tb-155. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Dopant-mediated structural and magnetic properties of TbMnO3

    Science.gov (United States)

    Sharma, Vinit; McDannald, A.; Staruch, M.; Ramprasad, R.; Jain, M.

    2015-07-01

    Structural and magnetic properties of the doped terbium manganites (Tb,A)MnO3 (A = Gd, Dy, and Ho) have been investigated using first-principles calculations and further confirmed by subsequent experimental studies. Both computational and experimental studies suggest that compared to the parent material, namely, TbMnO3 (with a magnetic moment of 9.7 μ B for Tb3+) Dy- and Ho-ion substituted TbMnO3 results in an increase in the magnetic susceptibility at low fields ( ≤ 10.6 μ B for Dy3+ and Ho3+). The observed spiral-spin AFM order in TbMnO3 is stable with respect to the dopant substitutions, which modify the Mn-O-Mn bond angles and lead to stronger the ferromagnetic component of the magnetic moment. Given the fact that magnetic ordering in TbMnO3 causes the ferroelectricity, this is an important step in the field of the magnetically driven ferroelectricity in the class of magnetoelectric multiferroics, which traditionally have low magnetic moments due to the predominantly antiferromagnetic order. In addition, the present study reveals important insights on the phenomenological coupling mechanism in detail, which is essential in order to design new materials with enhanced magneto-electric effects at higher temperatures.

  16. Neutron scattering study on R{sub 2}PdSi{sub 3} (R=Ho,Er,Tm) compounds

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Fei

    2010-12-14

    Previous studies on the family of inter-metallic rare-earth compounds R{sub 2}PdSi{sub 3} revealed multifaceted magnetic properties, for instance, spin-glass like behavior. Experimental observations include: Signs of a crystallographic superstructure, complicated magnetic structures both in zero field and in applied magnetic fields as well as a generic phase in applied fields for compounds in the series with the heavy rare-earths R=Gd, Tb, Dy, Ho, Er and Tm. This thesis expands the studies on the magnetic properties of R{sub 2}PdSi{sub 3} employing mainly neutron scattering on single crystals with the focus on the compounds with R=Ho, Er and Tm. A detailed analysis of the crystallographic superstructure using modulation wave approach and group theory is presented. The resulting structure implies the existence of two different rare-earth sites with reduced symmetry and an arrangement of the different sites according to sequences as determined by the superstructure. It is shown that the reduced symmetry of the rare-earth sites is explicitly observed in the energy spectra of inelastic neutron scattering. The results on the magnetic structures and excitations are shown and discussed in the framework of the superstructure model. Specifically the generic phase in applied fields is interpreted as a direct consequence of the crystallographic superstructure. It is rather unusual that a crystallographic superstructure is playing such a decisive, and through the field dependence also tunable role in determining the magnetic properties as observed in R{sub 2}PdSi{sub 3}. The mediating interactions between the crystallographic part and the magnetic part of the system are discussed. (orig.)

  17. Implantation sites of Ce and Gd in diamond

    CERN Document Server

    Bharuth-Ram, K; Hofsäss, H C; Ronning, C; Dietrich, M

    2002-01-01

    The implantation sites of rare earth (RE) probes /sup 141/Ce (t/sub 1 /2/=32 d) and /sup 149/Gd (t/sub 1/2/=9.28 d) in diamond have been investigated using the emission channeling (EC) technique. Parent isotopes /sup 141/Cs and /sup 149/Dy were implanted into type IIa, diamond samples at an energy of 60 keV at the online isotope separator ISOLDE at CERN. /sup 141/Cs decays through the chain /sup 141/Cs-/sup 141/Ba-/sup 141/La-/sup 141/Ce-/sup 141/ Pr. EC measurements were made on the 102 keV conversion electrons emitted in the decay of /sup 141/Pr to its ground state. The decay of /sup 149 /Dy follows the chain /sup 149/Dy-/sup 149/Tb-/sup 149/Gd-/sup 149 /Eu-/sup 149/Sm. EC measurements were made on the 101 keV electrons emitted in the decay of /sup 149/Eu. Two-dimensional channeling patterns of the conversion electrons were obtained along and axial directions by raster scans with a Si surface barrier detector. Comparison of the observed patterns with simulated spectra show that in diamond 45-50% of the RE...

  18. Suppression of superconductivity in GdPr-123 system

    International Nuclear Information System (INIS)

    Akhavan, M.; Yamani, Z.

    1997-01-01

    Fourteen single phase polycrystalline ceramic Gd/sub 1-x/ Pr/sub x/ Ba/sub 2/, Cu/sub 3/ O/sub 7-y/ (Gd Pr-123) samples with different Pr doping concentration, x, have been prepared by the standard sintering technique and characterized by FXRD, SEM, TGA, and DT. The electrical resistivity measurements show that at X/sub cr/ = 0.45 superconductivity disappears. These data show that the T/sub c/(x) curve has two plate aux which appear at a 0-0.05 and x = 0.15-0.25. hence T/sub c/ (x) in this system does not follow the prediction of the Abrijkosov- Gorkov (AG) magnetic pair breaking theory. Based on the qualitative similarities among the physical properties of this system and the oxygen depleted RBa/sub 2/Cu/sub 3/O/sub 7-y/ (R-123) (R:Y or rare earth except Ce, Pr, Tb, Pm) system, such as T/sub c/(x) to T/sub c/(y) rho (T,x) to rho (T,y), we suggest that the increasing band filling and localization of states due to the disorder effects, together with Pr doping, could cause an 'effective' increasing of the oxygen deficiency in this system. This implies that a chain-plain correlation (CPC) effect is responsible for the high-T/sub c/ superconductivity. (author)

  19. Vreden er over os

    DEFF Research Database (Denmark)

    Mehlsen, Camilla

    2006-01-01

    Urolige elever, cyklister - der giver fuck-finger, aggressive demonstranter. Samtiden er på vej ind i en æra domineret af vrede, siger rektor Lars-Henrik Schmidt, der er aktuel med bogen 'Om vreden'. Udgivelsesdato: Juni...

  20. MIT HJEM ER HVOR MIT HJERTE ER

    DEFF Research Database (Denmark)

    Høst, Jeppe Engset

    2014-01-01

    Ideen om at arbejde med det man kalder de stedbundne ressourcer på en ny måde, er relevant på Bornholm hvor events som blandt andet festivalen ’Wonderfestiwall’, strandfesten ’Vang Pier Beach Party’, karnevallet ’Svaneke Beach Party, kokkekonkurrencen ’Sol over Gudhjem’ og filmfestivalen ’Bornsho...

  1. Gd3+-ESR and magnetic susceptibility of GdCu4Al8 and GdMn4Al8

    International Nuclear Information System (INIS)

    Coldea, R.; Coldea, M.; Pop, I.

    1994-01-01

    Gd ESR of GdCu 4 Al 8 and GdMn 4 Al 8 and magnetic susceptibility of GdCu 4 Al 8 , GdMn 4 Al 8 , and YMn 4 Al 8 were measured in the temperature range of 290K--460K and 90K--1050K, respectively. The occurrence of the Mn moment in YMn 4 Al 8 and GdMn 4 Al 8 is strongly correlated with the critical value of d∼2.6 angstrom of the Mn-Mn distance below which the Mn moment is not stable. The experimental data for GdMn 4 Al 8 , compared with the data for the isostructural compounds GdCu 4 Al 8 and YMn 4 Al 8 , show that near the critical value of d, the existence of Mn moment depends not only on the value of d, but also on the local magnetic surroundings. It has been revealed that the magnetic character of Mn moment in YMn 4 Al 8 and GdMn 4 Al 8 changes from an itinerant electron type to a local-moment type with increasing temperature

  2. Litigation as TB Rights Advocacy

    Science.gov (United States)

    2016-01-01

    Abstract One thousand people die every day in India as a result of TB, a preventable and treatable disease, even though the Constitution of India, government schemes, and international law guarantee available, accessible, acceptable, quality health care. Failure to address the spread of TB and to provide quality treatment to all affected populations constitutes a public health and human rights emergency that demands action and accountability. As part of a broader strategy, health activists in India employ Public Interest Litigation (PIL) to hold the state accountable for rights violations and to demand new legislation, standards for patient care, accountability for under-spending, improvements in services at individual facilities, and access to government entitlements in marginalized communities. Taking inspiration from right to health PIL cases (PILs), lawyers in a New Delhi-based rights organization used desk research, fact-findings, and the Right To Information Act to build a TB PIL for the Delhi High Court, Sanjai Sharma v. NCT of Delhi and Others (2015). The case argues that inadequate implementation of government TB schemes violates the Constitutional rights to life, health, food, and equality. Although PILs face substantial challenges, this paper concludes that litigation can be a crucial advocacy and accountability tool for people living with TB and their allies. PMID:27781000

  3. TB deaths reach historic levels. International (global).

    Science.gov (United States)

    More tuberculosis (TB)-related deaths occurred in 1995 than in any other year in history (almost 3 million, vs. 2.1 million for the TB epidemic around 1990). In the next 50 years, as many as 500 million people may develop TB if current rates continue. More and more of these people will develop multidrug resistant TB. TB affects all social groups. It is the leading fatal infection in youth and adults. HIV positive people are more likely to die from TB than any other condition. More women die from TB than all causes of maternal mortality combined. Almost 50% of the world's refugees may have TB. All people are at risk of TB since TB bacteria, which enter the air via coughing or sneezing, can be suspended in the air for hours. Increased air travel and migration have brought TB back to industrialized countries. Multi-drug resistant TB has emerged in New York City, London, Milan, Paris, Atlanta, Chicago, and cities in developing countries. Governments of industrialized and developing countries have been slow to understand the effects of multi-drug resistant TB for public health. During the 1970s and 1980s, TB was greatly neglected resulting in the current multi-drug resistant TB epidemic. Policy makers have not applied the tools discovered by scientists to help eliminate TB. The World Health Organization recommends directly observed treatment, short-course (DOTS) to fight TB. DOTS can increase the number of cured TB patients two-fold. It can cure almost 95% of TB patients with medicines costing less than $11 in some areas of the world. Yet DOTS is being used to cure only 10% of all TB patients in the world. If it were used in Bangladesh, Brazil, China, Ethiopia, India, Indonesia, Mexico, Nigeria, Pakistan, Russian Federation, South Africa, and Zaire, about 75% of all TB cases would be cured. In DOTS, health workers, not the TB patient, are responsible for curing the TB patient. Poor patient compliance is responsible for the current TB epidemic because TB patients remain

  4. Synthesis and up-conversion emissions of Yb3+/Er3+, Yb3+/Tm3+ ...

    Indian Academy of Sciences (India)

    42

    microscopy (FE-SEM) results suggested the additive adding had effects on the size and the morphology of the material, which affected the UC emissions further. Green/Red UC emissions of Er3+, UV/blue/IR UC emissions of Tm3+, and UV UC emissions of Gd3+ were observed in the orthorhombic phase of KLu2F7 ...

  5. The correlation of the magnetic properties and the magnetocaloric effect in (Gd1-xErx)NiAl alloys

    International Nuclear Information System (INIS)

    Korte, B.J.; Pecharsky, V.K.; Gschneidner, K.A. Jr.

    1998-01-01

    A study of the magnetic properties of several (Gd 1-x Er x )NiAl alloys (where x=0, 0.30, 0.40, 0.46, 0.50, 0.55, 0.60, 0.80, and 1.00) was undertaken using both ac and dc magnetic and heat capacity measurements in an attempt to understand the table-like magnetocaloric effect previously observed in (Gd 0.54 Er 0.46 )NiAl. Results indicate the presence of both antiferromagnetic and ferromagnetic ordering processes in all alloys containing Gd. For ErNiAl, a metamagnetic transition from an antiferromagnetic ground state was observed. Within each alloy, several magnetic transitions occur over a temperature range from 10 K [in (Gd 0.20 Er 0.80 )NiAl] up to 35 K (in GdNiAl), with all but the lowest temperature transition shifting to higher temperatures with increasing Gd content. The change in magnetic entropy (ΔS mag ) induced by a change in field is observed to peak around the Nacute eel temperature for ErNiAl while gradually broadening and shifting toward the Curie temperature as the Gd content is increased. For Gd-rich alloys, a significant contribution to ΔS mag is observed at both the low and high temperature transitions, resulting in a rounded, skewed caret-like temperature profile of the magnetocaloric effect. Factors, which are believed to contribute to this effect, include the presence and temperature spacing of multiple zero-field transitions, which most likely result from competing anisotropy and exchange interactions within a frustrated hexagonal spin lattice. This leads to broad peaks in the magnetic heat capacity that span several transition temperatures, providing for a substantial ΔS mag over an extended temperature range. This characteristic is desired for application to magnetic refrigeration, where certain thermodynamic cycles (e.g., Ericsson cycle) require specific temperature profiles of the magnetocaloric effect in refrigerant materials (e.g., a constant change in magnetic entropy as a function of temperature within the region of cooling). In

  6. Biomarkers of latent TB infection

    DEFF Research Database (Denmark)

    Ruhwald, Morten; Ravn, Pernille

    2009-01-01

    For the last 100 years, the tuberculin skin test (TST) has been the only diagnostic tool available for latent TB infection (LTBI) and no biomarker per se is available to diagnose the presence of LTBI. With the introduction of M. tuberculosis-specific IFN-gamma release assays (IGRAs), a new area...... of in vitro immunodiagnostic tests for LTBI based on biomarker readout has become a reality. In this review, we discuss existing evidence on the clinical usefulness of IGRAs and the indefinite number of potential new biomarkers that can be used to improve diagnosis of latent TB infection. We also present...... early data suggesting that the monocyte-derived chemokine inducible protein-10 may be useful as a novel biomarker for the immunodiagnosis of latent TB infection....

  7. Radiation characteristics of GD-2 fuel

    International Nuclear Information System (INIS)

    Chrapciak, V.

    2008-01-01

    The assembly WWER-440 type Gd-2 has radial profile of enrichment and has 6 pins with Gd 2 O 3 . The maximal enrichment is 4.4%. Some analyses are done for assembly with flat enrichment (4.4%) and without Gd 2 O 3 . In this article are compared some characteristics (decay heat, some nuclide concentration, photon and gamma sources) for real Gd-2 assembly and for flat 4.4% assembly. The TRITON module (in SCALE 5.1) was used. (Author)

  8. Screening contacts of patients with extrapulmonary TB for latent TB infection.

    Science.gov (United States)

    Humphreys, Anna; Abbara, Aula; Williams, Sion; John, Laurence; Corrah, Tumena; McGregor, Alastair; Davidson, Robert N

    2018-03-01

    2016 TB National Institute for Health and Care Excellence (NICE) guidelines imply that contacts of extrapulmonary TB do not require screening for latent TB infection. At our high TB prevalence site, we identified 189 active cases of TB for whom there were 698 close contacts. 29.1% of the contacts of pulmonary TB and 10.7% of the contacts of extrapulmonary TB had active or latent TB infection. This supports screening contacts of extrapulmonary TB at our site and presents a way to access high-risk individuals. We propose to continue to screen the contacts of our patients with extrapulmonary TB and recommend other TB units audit their local results. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  9. er 2000

    DEFF Research Database (Denmark)

    Jensen, J. P.; Søndergaard, M.; Jeppesen, E.

    -kommunale data og rapporter af over-vågningen af de ferske vande. Rapporten Marine områder - Status over miljøtilstanden i 2000 er ba-seret på amtskommunale data og rapporter af overvågningen af kystvande og fjorde samt Dan-marks Miljøundersøgel-sers og vore nabolandes over-vågning af de åbne havområder....... Rapporten Landover-vågningsoplande er baseret på data indbe-rettet af amtskommuner-ne fra 7 overvågnings-oplande og er ud-arbejdet i samarbejde med Danmarks Geologi-ske Un-dersøgel-ser. Endelig er rapporten Atmosfærisk deposition 2000 baseret på Danmarks Miljø-undersø-gelsers overvågning af luftkvaliteten i...

  10. TB in Wild Asian Elephants

    Centers for Disease Control (CDC) Podcasts

    2017-05-10

    Dr. Susan Mikota, co-founder of Elephant Care International, discusses TB in wild Asian elephants.  Created: 5/10/2017 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 5/10/2017.

  11. Community Involvement in TB Research

    NARCIS (Netherlands)

    M. van der Werf (Marloes); S.G. Heumann (Silke); E.M.H. Mitchell

    2011-01-01

    textabstractWhile communities at risk have been both drivers and partners in HIV research, their important role in TB research is yet to be fully realized. Involvement of communities in tuberculosis care and prevention is currently on the international agenda. This creates opportunities and

  12. Extensively Drug-Resistant TB

    Centers for Disease Control (CDC) Podcasts

    2016-12-16

    Dr. Charlotte Kvasnovsky, a surgery resident and Ph.D. candidate in biostatistics, discusses various types of drug resistance in TB patients in South Africa.  Created: 12/16/2016 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 12/16/2016.

  13. Jeg Er blevet FRANKofil

    DEFF Research Database (Denmark)

    Andersson, Lasse

    2014-01-01

    forhold til Frank, så har jeg holdt mig i skindet og har 5 timer tilbage med iPad og Frank Underwood….og hvilke timer! Hvorfor bruger jeg nu min klumme på Frank og Netflix? For det første så er House of Cards i mine øjne kunst og kultur. For det andet så er det sikkert, at streaming-tjenesterne kommer til...

  14. er 1999

    DEFF Research Database (Denmark)

    Jensen, J. P.; Søndergaard, M.; Jeppesen, E.

    små cladoceer og hjuldyr, og især er maksimumsforekom-sterne af calanoide vandlopper og de små og store cladoceer og daf-nier gået tilbage. Den gennemsnitlige biomasse af dafnier er derimod øget især p.g.a. stigning i de 25 % af søerne med størst forekomster. Dyreplanktons græsning Betragtet under et...

  15. TB control: challenges and opportunities for India.

    Science.gov (United States)

    Pai, Madhukar; Daftary, Amrita; Satyanarayana, Srinath

    2016-03-01

    India's TB control programme has treated over 19 million patients, but the incidence of TB continues to be high. TB is a major killer and drug-resistant TB is a growing threat. There are several likely reasons, including social conditions and co-morbidities that fuel the TB epidemic: under-investment by the government, weak programme implementation and management, suboptimal quality of care in the private sector, and insufficient advocacy around TB. Fortunately, India possesses the technical know-how, competence and resources to address these challenges. The End TB Strategy by WHO offers India an excellent blueprint to advance the agenda of TB control. © The Author 2016. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  16. The Gd{sub 14}Ag{sub 51} structure type and its relation to some complex amalgam structures

    Energy Technology Data Exchange (ETDEWEB)

    Tambornino, Frank; Sappl, Jonathan; Hoch, Constantin, E-mail: constantin.hoch@cup.uni-muenchen.de

    2015-01-05

    Highlights: • The Gd{sub 14}Ag{sub 51} structure type has been revisited on the basis of single crystal diffraction data. • Symmetry analysis from electron density and TEM shows the space group P6/m to be true. • Gd{sub 14}Ag{sub 51} shows good metallic behaviour. • Structure relations to alkali, alkaline-earth and rare-earth metal amalgams can be established. • Complexity values for the RE{sub 14}Ag{sub 51} structure family were calculated. - Abstract: A plethora of binary and ternary intermetallic compounds has been assigned to the Gd{sub 14}Ag{sub 51} structure type, crystallising in the hexagonal system (space group P6/m, a = 1264.30(18) pm, c = 933.58(11) pm for Gd{sub 14}Ag{sub 51}). Starting in the late 1960s, much work has been invested in the structural elucidation of these crystal structures. However, reliable single crystal data are scarce, and most structure type assignments have been performed merely on the basis of powder data. We have redetermined four representatives of the binary RE{sub 14}Ag{sub 51} structure type (RE = Y, Ce, Gd, Tb) with modern high-precision single crystal X-ray methods. The assignment of the Gd{sub 14}Ag{sub 51} structure type to space group P6/m was additionally verified by careful analysis of high resolution transmission electron micrographs. We emphasise the close relation of the Gd{sub 14}Ag{sub 51} structure type to the structures of some recently described amalgams of similar composition focussing on disorder phenomena and structural complexity. Furthermore, we provide detailed information on synthesis as well as electrical and magnetic properties for Gd{sub 14}Ag{sub 51}, the parent compound of this structure family.

  17. Investigation of Gd compounds using synchrotron radiation

    International Nuclear Information System (INIS)

    Tyszka, B.; Szade, J.; Burian, W.; Skorek, G.; Deniszczyk, J.; Sikora, M.; Zajac, D.; Kapusta, Cz.; Matteucci, M.; Bondino, F.; Zacchigna, M.; Zangrando, M.

    2005-01-01

    The electronic structure of ferromagnetic compound GdTiGe has been investigated using element sensitive methods-X-ray absorption spectroscopy (XAS), X-ray magnetic circular dichroism (XMCD) and resonant inelastic X-ray scattering (RIXS). Additionally, another ferromagnet GdTiSi has been studied using XMCD. XMCD revealed a strong dichroic signal at Gd L 2 and L 3 edges, which can be related to polarisation of Gd 5d band. XAS at Ti L 2,3 edges has exhibited a structure which appeared to be in general agreement with the LAPW calculations. RIXS spectra have shown some resonance features for photon energies close to Ti L 2 and Gd M 5 edges

  18. Magnetism at the V/Gd interface

    International Nuclear Information System (INIS)

    Mouketo, L; M'Passi-Mabiala, B; Binggeli, N

    2010-01-01

    Recent experimental investigations into the magnetic properties of V/Gd bilayers have shown that vanadium, which is nonmagnetic in the bulk, can acquire a magnetic moment in such systems. We have performed ab initio pseudopotential calculations to examine the magnetic behavior of V(110)/Gd(0001) bilayers for V layers with thicknesses up to 4 monolayers (ML). We considered both abrupt and atomic intermixed V/Gd interfaces. In both cases, the magnetic moment of the V layer is found to align antiparallel to the moment of the Gd layer, consistent with the experimental observation. However, the magnitude of the V moment at the abrupt interface is considerably smaller than the moments reported experimentally. In the presence of atomic intermixing, instead, substantially larger V moments are found, closer to the experimentally reported moments. On the basis of the calculated atomic and spin resolved density of states, we discuss the possible mechanism responsible for the observed Gd-V antiferromagnetic coupling.

  19. The elastic and magnetic properties of a single-crystal Gd-40%Y alloy

    International Nuclear Information System (INIS)

    Palmer, S.B.; Isci, C.; Hukin, D.

    1977-01-01

    The five independent single-crystal elastic constants of hexagonal Gd-40%Y have been measured in the temperature range 4.2 to 300 K and in magnetic fields of up to 7 T. This temperature and magnetic field range covers the different magnetic states of the material and has allowed the magnetic phase diagram to be constructed from the anomalies present in the elastic constants and associated ultrasonic attenuation. At low temperatures and low fields the material does not follow Dy and Tb-50%Ho in transforming from an antiferromagnetic to a ferromagnetic phase, but exhibits a variety of more complicated magnetic structures. (author)

  20. Staying on Track with TB Medicine

    Science.gov (United States)

    ... will help show if your TB medicines are working the right way and how your body is handling the medicine. If you are being treated for TB disease, you may also get additional chest x-rays. • If you have TB disease along with other ...

  1. Measurement of 160Tb and 161Tb in nuclear forensics samples

    International Nuclear Information System (INIS)

    Jiang, J.; Davies, A.V.; Britton, R.E.

    2017-01-01

    160 Tb and 161 Tb are important radionuclides to measure when analysing a Nuclear Forensics sample. An analytical method for the measurement of both 160 Tb and 161 Tb was developed in this study. Terbium was separated and purified using exchange resin and TrisKem LN Resin. The purified fraction containing 160 Tb and 161 Tb was measured by gamma spectrometry and liquid scintillation counting. The counting efficiencies of 160 Tb and 161 Tb were determined using the CIEMAT/NIST efficiency tracing method. The LSC count rate ratio, R160 Tb /R161 Tb , on the reference date was determined by sequential counting and calculated using a custom script based on their half-lives. (author)

  2. Relationship between National TB program and prevalence of TB drug resistance in Algeria, 1965 to 2013

    OpenAIRE

    Fadila Boulahbal

    2015-01-01

    The Algerian National TB program was first implemented in Algeria in 1965. Since 1965, the Ministry of Health has endorsed many instructions which have given important improvements in the fight against tuberculosis (TB) in the country. The government has actively participated in the fight against TB as expressed in its endorsement of many decisions to this end, such as the withdrawal of TB medications from the private pharmacies, the free-of-charge diagnostics and the treatment for TB pati...

  3. Magnetic and magnetocaloric properties of partially disordered RFeAl (R = Gd, Tb) intermetallic

    Czech Academy of Sciences Publication Activity Database

    Kaštil, Jiří; Javorský, P.; Kamarád, Jiří; Diop, L.V.B.; Isnard, O.; Arnold, Zdeněk

    2014-01-01

    Roč. 54, Nov (2014), s. 15-19 ISSN 0966-9795 Institutional support: RVO:68378271 Keywords : magnetic properties * thermodynamic properties * energy systems Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.131, year: 2014

  4. Thermophysical properties of Gd{sub 2}Zr{sub 2}O{sub 7} powders prepared by mechanical milling: Effect of homovalent Gd{sup 3+} substitution

    Energy Technology Data Exchange (ETDEWEB)

    Díaz-Guillén, J.A., E-mail: jadiaz@itsaltillo.edu.mx [División de Estudios de Posgrado e Investigación, Instituto Tecnológico de Saltillo, 25280 Saltillo, Coahuila (Mexico); Durá, O.J. [GFMA, Departamento de Física Aplicada, Escuela Técnica Superior de Ingenieros Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain); Díaz-Guillén, M.R. [Instituto de Investigaciones Eléctricas, 62490 Cuernavaca, Morelos (Mexico); Bauer, E. [Institute of Solid State Physics, Vienna University of Technology, Wien A-1040 (Austria); López de la Torre, M.A. [GFMA, Departamento de Física Aplicada, Escuela Técnica Superior de Ingenieros Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain); Fuentes, A.F. [Cinvestav Unidad Saltillo, Apartado Postal 663, 25000 Saltillo, Coahuila (Mexico)

    2015-11-15

    This contribution analyzes the thermophysical properties of Gd{sub 1.6}Ln{sub 0.4}Zr{sub 2}O{sub 7} (Ln = La{sup 3+}, Nd{sup 3+}, Sm{sup 3+}, Dy{sup 3+} and Er{sup 3+}) ceramics synthesized at room temperature, by mechanically milling stoichiometric mixtures of high purity oxides. Regardless of chemical composition, powders milled for 27 h show XRD patterns similar to fluorite-type materials. Post-milling thermal treatments at 1500 °C, facilitates the evolution to the ordered pyrochlore derivative for Gd{sub 2}Zr{sub 2}O{sub 7}, and the La{sup 3+}-, Nd{sup 3+}-, and Sm{sup 3+}-containing materials. By contrast, samples containing the smaller lanthanides (Dy{sup 3+} or Er{sup 3+}), maintain the fluorite structure. Thermal conductivity of the as-prepared samples was obtained as a function of temperature, from thermal diffusivity, heat capacity and density values, using sintered pellets. We found that doping has an important effect in lowering Gd{sub 2}Zr{sub 2}O{sub 7} thermal conductivity, with final values ranging from 1.22 to 1.94 W m{sup −1} K{sup −1}; Nd{sup 3+}- and Er{sup 3+}-containing samples represent an optimum combination of defects and disordering of oxygen vacancies that generate the lowest conductivity values of all samples tested. - Highlights: • Gd{sub 2}Zr{sub 2}O{sub 7} doped with different lanthanides was synthesized by mechanical milling. • Smaller Ln{sup 3+} yield fluorites whereas larger lanthanides produce pyrochlores. • Thermophysical properties of the samples were measured as a function of temperature. • All samples show low thermal conductivities, and might find application as TBCs. • Doping is a valid strategy to increase Gd{sub 2}Zr{sub 2}O{sub 7} thermal resistance.

  5. NMR measurements in milled GdCo2 and GdFe2 intermetallic compounds

    International Nuclear Information System (INIS)

    Tribuzy, C.V.B.; Guimaraes, A.P.; Biondo, A.; Larica, C.; Alves, K.M.B.

    1998-12-01

    We have used the nuclear magnetic resonance technique to study the magnetic and structural properties of the Gd-Co and Gd-Fe metallic systems, starting with the C15 laves phase intermetallic compounds, and submitting them to a high energy milling process. This leads to the amorphization of the samples, as determined by the X-ray diffraction spectra. For the Gd-Co system the NMR study used the 59 Co nucleus; in the Gd-Fe system, 155,157 Gd and 57 Fe were used. Both systems showed segregation of the pure elements, after a few hours of milling. In the Gd-Co system, a single line, of increasing width, was observed in the 59 Co spectrum. In the Gd-Fe system, the 155 Gd and 157 Gd resonances show three lines, arising from electrical quadrupole interaction. With increasing milling time, the lines broaden, and extra lines appear attributed to a cubic phase of Gd; this interpretation is supported by the X-ray analysis of the samples. The 57 Fe NMR spectrum of this system also informs on the direction of magnetization of the samples in the early stages of milling. From 1 h to 7 h of milling, a spectrum of α-Fe was observed. The study of the NMR line intensity as a function of radio frequency (r.f.) power in Gd Co 2 suggests the existence of regions of the samples with different degrees of disorder. We have observed the persistence of NMR signals from the original intermetallic compounds in the samples with up to 10 h and 7 h of milling, respectively, for Gd Co 2 and Gd Fe 2 . (author)

  6. Ondskaben er fortryllende

    DEFF Research Database (Denmark)

    Schubart, Rikke

    2013-01-01

    Indlæg om tv-serien Once Upon a Time (2011-), der hører til genren fairytale fantasy, der blander eventyr og fantasy. Her bliver alle eventyr brugt i en fortælling om alle beboere i en lille by, der ikke ved, at de i virkeligheden er eventyr-karakterer.......Indlæg om tv-serien Once Upon a Time (2011-), der hører til genren fairytale fantasy, der blander eventyr og fantasy. Her bliver alle eventyr brugt i en fortælling om alle beboere i en lille by, der ikke ved, at de i virkeligheden er eventyr-karakterer....

  7. Determination of the excitation energy of high spin isomers

    International Nuclear Information System (INIS)

    Bjoernholm, S.; Borggreen, J.; Christensen, O.; Del Zoppo, A.; Herskind, B.; Pedersen, J.; Sletten, G.

    1979-01-01

    The sum spectrometer technique to study delayed radiation is discussed. Results on half-lives and isomer excitation energies are presented for 144 Gd, 147 Gd, 148 Tb, 151 Dy, 152 Dy, 149-153 Ho, 151 Er, 152 Er, 153 Er, and 154 Er. 2 figures, 1 table

  8. Physico-chemical characterization of terbium-161-chloride (161TbCl3) radioisotope from irradiated natural gadolinium oxide target

    International Nuclear Information System (INIS)

    Azmairit Aziz; Nana Suherman

    2015-01-01

    Currently cancer patients are increasing every year in Indonesia and become the third leading cause of death after heart disease and high blood pressure. Terbium-161 ( 161 Tb) is a low β- emitter (E β - = 0.155 MeV, T 1/2 = 6.9 d) and very similar to 177 Lu in terms of half-life, E β - energy and chemical properties.However, 161 Tb also ejects internal conversion electrons and Auger electrons which can provide a greater therapeutic effect than 177 Lu. Radioisotope of 161 Tb can be produced as a carrier-free for use in labeling of biomolecules as a targeted radiopharmaceutical for cancer therapy. 161 Tb was obtained through 160 Gd(n,γ) 161 Tb nuclear reaction by thermal neutron bombardment on 100 mg of natural gadolinium oxide target in RSG-G.A. Siwabessy at a thermal neutron flux of ~10 14 n.cm -2 .s -1 and followed by radiochemical separation of 161 Tb from Gd isotopes using extraction chromatography method. The physico-chemical characterization of 161 TbCl 3 solution was studied by determination of its radionuclide purity by means of a γ-rays spectrometry with HP-Ge detector coupled to a multichannel analyzer (MCA). Radiochemical purity was determined using paper chromatography and paper electrophoresis methods. The results showed that 161 TbCl 3 radioisotope has a pH of 2, radiochemical purity of 99.64 ± 0.34%, radionuclide purity of 99.69 ± 0.20%, specific activity and radioactive concentration at the end of irradiation (EOI) of 2.26 – 5.31 Ci/mg and 3.84 – 9.03 mCi/mL, respectively. 161 TbCl 3 solution stable for 3 weeks at room temperature with a radiochemical purity of 98.41 ± 0.42%. 161 TbCl 3 solution from irradiated natural gadolinium oxide target has the physico-chemical characteristic that meets the requirements for use as a precursor in preparation of radiopharmaceuticals. (author)

  9. Preparation and spectral analysis of a new Tb3+-doped CaO-MgO-SiO2 glass ceramics

    International Nuclear Information System (INIS)

    Cheng Jinshu; Tian Peijing; Zheng Weihong; Xie Jun; Chen Zhenxia

    2009-01-01

    Tb 3+ -doped CaO-MgO-SiO 2 glass ceramics have been prepared and characterized. The structure and optical properties of the glass ceramics were studied by XRD, SEM, Raman, and fluorescence spectra. The precipitated crystalline phase in the glass ceramics was columnar CaMgSi 2 O 6 . Raman spectra showed the introduction of rare earth nearly had no influence on the sample structure. Fluorescence measurements showed that Tb 3+ ions entered into the diopside crystalline phase and induced a much stronger emission in the glass ceramics than that in the corresponding glass. With increase of Tb 3+ content and the introduction of Gd 3+ , the fluorescence intensity of the luminescent glass ceramic increased

  10. Isothermal section of the Er-Fe-Al ternary system at 800 oC

    International Nuclear Information System (INIS)

    Jemmali, M.; Walha, S.; Pasturel, M.; Tougait, O.; Ben Hassen, R.; Noel, H.

    2010-01-01

    Physico-chemical analysis techniques, including X-ray diffraction and Scanning Electron Microscope-Energy Dispersive X-ray Spectroscopy, were employed to construct the isothermal section of the Er-Fe-Al system at 800 o C. At this temperature, the phase diagram is characterized by the formation of five intermediate phases, ErFe 12-x Al x with 5 ≤ x ≤ 8 (ThMn 12 -type), ErFe 1+x Al 1-x with -0.2 ≤ x ≤ 0.75 (MgZn 2 -type), ErFe 3-x Al x with 0.5 2 Al-type), Er 2 Fe 17-x Al x with 4.74 ≤ x ≤ 5.7 (TbCu 7 -type) and Er 2 Fe 17-x Al x with 5.7 2 Zn 17 -type), seven extensions of binaries into the ternary system; ErFe x Al 3-x with x 3 Cu-type), ErFe x Al 2-x with x ≤ 0.68 (MgCu 2 -type), Er 2 Fe x Al 1-x with x ≤ 0.25 (Co 2 Si-type), ErFe 2-x Al x with x ≤ 0.5 (MgCu 2 -type), ErFe 3-x Al x with x ≤ 0.5 (Be 3 Nb-type), Er 6 Fe 23-x Al x with x ≤ 8 (Th 6 Mn 23 -type), and Er 2 Fe 17-x Al x with x ≤ 4.75 (Th 2 Ni 17 -type) and one intermetallic compound; the ErFe 2 Al 10 (YbFe 2 Al 10 -type).

  11. TB Anywhere Is TB Everywhere: The Intersection of U.S. Immigration Enforcement Policy and TB

    Science.gov (United States)

    2016-09-01

    is not the primary goal (e.g., in high turnover jails or in some homeless shelters ).316 The ACET does not define a “high turnover jail,” but the...conflicts with religious practices, a stigma associated with TB infection, lack of financial resources, poor access to healthcare, frequently changing...residences, and an inability to attend DOT sessions due to lack of transportation or work schedule.125 D. TUBERCULOSIS IN SELECTED COUNTRIES OF INTEREST

  12. Time domain simulation of Gd3+-Gd3+ distance measurements by EPR

    Science.gov (United States)

    Manukovsky, Nurit; Feintuch, Akiva; Kuprov, Ilya; Goldfarb, Daniella

    2017-07-01

    Gd3+-based spin labels are useful as an alternative to nitroxides for intramolecular distance measurements at high fields in biological systems. However, double electron-electron resonance (DEER) measurements using model Gd3+ complexes featured a low modulation depth and an unexpected broadening of the distance distribution for short Gd3+-Gd3+ distances, when analysed using the software designed for S = 1/2 pairs. It appears that these effects result from the different spectroscopic characteristics of Gd3+—the high spin, the zero field splitting (ZFS), and the flip-flop terms in the dipolar Hamiltonian that are often ignored for spin-1/2 systems. An understanding of the factors affecting the modulation frequency and amplitude is essential for the correct analysis of Gd3+-Gd3+ DEER data and for the educated choice of experimental settings, such as Gd3+ spin label type and the pulse parameters. This work uses time-domain simulations of Gd3+-Gd3+ DEER by explicit density matrix propagation to elucidate the factors shaping Gd3+ DEER traces. The simulations show that mixing between the |+½, -½> and |-½, +½> states of the two spins, caused by the flip-flop term in the dipolar Hamiltonian, leads to dampening of the dipolar modulation. This effect may be mitigated by a large ZFS or by pulse frequency settings allowing for a decreased contribution of the central transition and the one adjacent to it. The simulations reproduce both the experimental line shapes of the Fourier-transforms of the DEER time domain traces and the trends in the behaviour of the modulation depth, thus enabling a more systematic design and analysis of Gd3+ DEER experiments.

  13. Energies, Wavelengths, and Transition Rates for Ga-Like Ions (Nd XXX-Tb XXXV)

    Science.gov (United States)

    El-Sayed, Fatma; Attia, S. M.

    2016-03-01

    Energies, wavelengths, transition probabilities, oscillator strengths, and line strengths have been calculated for 4s24p-4s4p2 and 4s24p-4s24d transitions in gallium-like ions from Z = 60 to 65, for Nd XXX, Pm XXXI, Sm XXXII, Eu XXXIII, Gd XXXIV, and Tb XXXV using the fully relativistic multiconfi guration Dirac-Fock method. The correlation with the n = 4 complex and the quantum electrodynamic effects have been considered in the calculations. The obtained results have been compared with the available experimental and other theoretical results.

  14. Er Isak bare paranoid?

    DEFF Research Database (Denmark)

    Raun, Tobias

    2017-01-01

    Med afsæt i hovedpersonen fra tredje sæson, Isak, ser artiklen nærmere på homoseksualitet og maskulinitet. I artiklen introduceres og anvendes centrale queer teoretiske begreber som ’homosocialitet’ og ’heteronormtivitet’. Der vises hvordan fællesskaberne i serien er bygget op omkring stærke homo...

  15. Scenen er blevet din

    DEFF Research Database (Denmark)

    Helms, Niels Henrik

    2008-01-01

    Verden kan betragtes som en skueplads med mange forskellige scener. I bidrgaet vil læseren kunne stifte bekendtskab med forskellige refleksioner over netop denne metaforik som analyseoptik i forhold til begrebet innovation. Afsættet er ønsket om at finde en måde at analysere og begrebsliggøre inn...

  16. Er tang fremtidens superfood?

    DEFF Research Database (Denmark)

    Holdt, Susan Løvstad

    seneste år fået øjnene op for tang indenfor områderne: biokemikalier og bioaktive stoffer, ekstraktion, gastronomi, produktudvikling, foder, bioraffinaderier, dyrkning osv. Men hvad er det tang kan? Dette foredrag vil vise at vi med tangdyrkning kan rykke mere bæredygtig fødevareproduktion ud på havet...

  17. Er praksis prima?

    DEFF Research Database (Denmark)

    Holm, Claus

    2006-01-01

    Tiltroen til praktisk sans er i vækst, mens den teoretiske fornuft møder skepsis. Paradoksalt nok rammer den antiteoretiske bevægelse også universiteterne. To forskere advarer mod, at samfundet forlader sig på praksis....

  18. Riget - alt er tilladt

    DEFF Research Database (Denmark)

    Agger, Gunhild

    2017-01-01

    Riget indtager en nøglestilling, når overgangen mellem faser i Triers produktion skal karakteriseres. Riget danner bro mellem den billedfascination og de radikale stileksperimenter, der præger Triers tidlige produktion, og den genre- og plotbevidsthed, der er typisk for film som Breaking the Waves...

  19. Hvad er tidligt sprog

    DEFF Research Database (Denmark)

    Skriver Jensen, Anders

    2009-01-01

    Forfatteren argumenterer for at "early literacy" kan oversættes til "tidligt sprog"; særligt når der er tale om en helhedsorienteret tilgang med vægt på sprog som et alsidigt medie for kommunikation- og betydningsskabelse. Med inspiration fra Jerome Bruners kulturpsykologi diskuteres mulige...

  20. Er danskerne racister

    DEFF Research Database (Denmark)

    Bech, Henning; Necef, Mehmet Ümit

    Igennem de seneste årtier er det blevet almindeligt at tale om, at der er en udbredt racisme i Danmark. Påstande om danskernes racisme, fremmedhad og diskrimination optræder dagligt i offentligheden og i medierne, og der henvises ofte til, hvad ’forskerne’ og de ’videnskabelige undersøgelser’ siger...... om emnet. Der kan da næppe heller være tvivl om, at der forekommer racistiske holdninger hos nogle danskere. Men er problemet så stort, som det gøres til i den offentlige debat? Bogen ønsker at afklare, hvorvidt der er videnskabelig dokumentation for påstandene om danskernes racisme. Den går i dybden...... med en række forskeres og eksperters udtalelser på området og præsenterer en grundig analyse af deres fremstilling af dansk racisme i forhold til emner som kultur, seksualitet, kriminalitet og arbejdsmarked....

  1. Litteratur er nyttig

    DEFF Research Database (Denmark)

    Kaspersen, Peter

    2012-01-01

    Den anmeldte bog er en forskningsbaseret debatbog om hvilken nytteværdi litteratur har. Bogen placeres i sammenhæng med en række bøger på nordiske sprog og engelsk om litteraturens, litteraturundervisningens og -forskningens legitimitet. Argumentatioen i bogen bygger på Bakhtins litteratursyn, og...

  2. Strongly coupled band in 140Gd

    International Nuclear Information System (INIS)

    Falla-Sotelo, F.; Oliveira, J.R.B.; Rao, M.N.

    2005-01-01

    Several high-K states are known to exist in the mass 130-140 region. For the N=74 even-even isotopes, Kπ = 8 - isomers, with lifetimes ranging from ns to ms, are known in 128 Xe, 130 Ba, 132 Ce, 134 Nd, 136 Sm, and 138 Gd[. In 140 Gd, we have observed for the first time a band also based on an Iπ = 8 - state. This could be the first case of a Kπ = 8 - state observed in an N=76 even-even isotope. The systematics of the Kπ = 8 - isomeric states in N=74 isotopes has been studied by A.M. Bruce et al. These states decay towards the K = 0 ground state band, and the transitions are K-forbidden. The 140 Gd case presents strong similarities but also some significant differences with relation to the N=74 isotopes. We propose the same configuration but with larger deformation in 140 Gd

  3. Energy transfer processes in Tb(III)-dibenzoylmethanate complexes with phosphine oxide ligands

    Energy Technology Data Exchange (ETDEWEB)

    Silva Junior, Francisco A.; Nascimento, Helenise A.; Pereira, Dariston K.S.; Teotonio, Ercules E.S.; Espinola, Jose Geraldo P.; Faustino, Wagner M., E-mail: teotonioees@quimica.ufpb.br [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil). Departamento de Quimica; Brito, Hermi F. [Universidade de Sao Paulo (USP), SP (Brazil). Instituto de Quimica. Departamento de Quimica Fundamental; Felinto, Maria Claudia F.C. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), SP (Brazil); Sa, Gilberto F. [Universidade Federal de Pernambuco (UFPE/CCEN), Recife, PE (Brazil). Centro de Ciencias Exatas e da Natureza. Departamento de Quimica Fundamental

    2013-04-15

    The Tb{sup 3+}-{beta}-diketonate complexes [Tb(DBM){sub 3}L], [Tb(DBM){sub 2}(NO{sub 3})L{sub 2}] and [Tb(DBM)(NO{sub 3}){sub 2} (HMPA){sub 2}] (DBM = dibenzoylmethanate; L: TPPO triphenylphosphine oxide or HMPA=hexamethylphosphine oxide) were prepared and characterized by elemental analysis (CHN), complexometric titration with EDTA and Fourier transform infrared (FTIR) spectroscopy, and the photoluminescence properties evaluated. The triplet state energies of the coordinated DBM ligands were determined using time-resolved phosphorescence spectra of analogous Gd{sup 3+} complexes. The results show that the energies increase along with the number of coordinated nitrate anions replacing the DBM ligand in the complexes. The luminescence spectra and emission lifetime measurements revealed that the ligand-to-metal energy transfer efficiency follows the same tendency. Unlike the tris-DBM complexes, bis- and mono-DBM presented high luminescence, and may act as promising candidates for preparation of the emitting layer of light converting molecular devices (LCMDs). (author)

  4. TB

    African Journals Online (AJOL)

    Tuberculous spondylitis/spondylodiscitis is caused by the Mycobacterium tuberculosis bacillus. The features of the disease were first described by. Percival Pott. The disease has potentially serious morbidity with severe neurological impairment and disfiguring deformity. Also known as Pott's disease, spinal infection follows ...

  5. Evaluation of Gd and Gd{sup 159} as new approaches for cancer treatment

    Energy Technology Data Exchange (ETDEWEB)

    Galvao, I.; Neves, M.J., E-mail: nevesmj@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Grupo de Desenvolvimento de Radiofarmacos; Santos, R.G., E-mail: santosr@cdtn.br [Instituto Nacional de Ciencia e Tecnologia em Medicina Molecular (INCT-MM), Belo Horizonte, MG (Brazil)

    2011-07-01

    Metal compounds have shown many biological activities and have been successfully used as anticancer agents such cisplatin. Actually gadolinium (Gd) complexed with a porphyrin Motexafin (MGd) has been investigated as redox-active compound for treatment of cancer. 1{sup 59G}d decays by beta emission with an energy of 970 keV and half-life of 18.59 hours. The de-excitation can be via gamma ray and internal conversion electron emission followed by auger electrons and x rays. Considering all of this 1{sup 59G}d could be a interesting radionuclide to be as a radio therapeutical agent. The aims of this works were to evaluate the cytotoxicity of Gd and 1{sup 59G}d on malignant brain tumors such as glioblastoma multiform, the most frequent brain tumors which has a very poor prognosis. For this purpose, it was used human glioblastoma cell lines T98 (mutant p53) and U87 (wild-type p53) to investigate the cytotoxicity of gadolinium on cell metabolism by MTT assay and also morphological changes, chromatin condensation by DAPI assay and ROS generation. Gadolinium was able to decrease cell viability, the cells presented morphological changes like round shapes and blebs formation after cell treatment with 5x10{sup -6}M of Gd. Nuclear changing and ROS generation occurred in a dose dependent way indicating the cytotoxic effect of Gd. Treatment with 1{sup 59G}d increased all of changes observed with treatment with Gd. These results state for an additive effect of metal toxicity and radioactivity inducing ROS generation as the main mechanism of anti tumoral action of 1{sup 59G}d. The results obtained indicated that the radioactive analogues of Gd have increased cytotoxic effects and gadolinium can be a metal of choice for development of new drugs for cancer treatment. (author)

  6. Why healthcare workers are sick of TB

    Directory of Open Access Journals (Sweden)

    Arne von Delft

    2015-03-01

    Full Text Available Dr Thato Mosidi never expected to be diagnosed with tuberculosis (TB, despite widely prevalent exposure and very limited infection control measures. The life-threatening diagnosis of primary extensively drug-resistant TB (XDR-TB came as an even greater shock. The inconvenient truth is that, rather than being protected, Dr Mosidi and thousands of her healthcare colleagues are at an increased risk of TB and especially drug-resistant TB. In this viewpoint paper we debunk the widely held false belief that healthcare workers are somehow immune to TB disease (TB-proof and explore some of the key factors contributing to the pervasive stigmatization and subsequent non-disclosure of occupational TB. Our front-line workers are some of the first to suffer the consequences of a progressively more resistant and fatal TB epidemic, and urgent interventions are needed to ensure the safety and continued availability of these precious healthcare resources. These include the rapid development and scale-up of improved diagnostic and treatment options, strengthened infection control measures, and focused interventions to tackle stigma and discrimination in all its forms. We call our colleagues to action to protect themselves and those they care for.

  7. Hvid er et usynligt ideal

    DEFF Research Database (Denmark)

    Mehlsen, Camilla

    2010-01-01

    Salget af hudblegecremer er eksploderet. Hvorfor drømmer så mange om at få lys hud? Hvorfor vil børn hellere lege med hvide dukker end brune? Svaret er, at hvid er et globalt ideal. Interview med Dorthe Staunæs og Les Back....

  8. Er HR ude i tovene?

    DEFF Research Database (Denmark)

    Poulfelt, Flemming

    2015-01-01

    HR: Er der behov for nytænkning i HR-land? Artikler i Harvard Business Review - bakket op af en dansk undersøgelse - konkluderer, at HR stadig mangler gennemslagskraft i virksomhederne. Er HR ude i tovene? ... For i undersøgelsen "Ny Dansk Ledelse" (maj 2015), som er baseret på danske lederes...

  9. Macrocyclic Gd(3+) complexes with pendant crown ethers designed for binding zwitterionic neurotransmitters.

    Science.gov (United States)

    Oukhatar, Fatima; Meudal, Hervé; Landon, Céline; Logothetis, Nikos K; Platas-Iglesias, Carlos; Angelovski, Goran; Tóth, Éva

    2015-07-27

    A series of Gd(3+) complexes exhibiting a relaxometric response to zwitterionic amino acid neurotransmitters was synthesized. The design concept involves ditopic interactions 1) between a positively charged and coordinatively unsaturated Gd(3+) chelate and the carboxylate group of the neurotransmitters and 2) between an azacrown ether appended to the chelate and the amino group of the neurotransmitters. The chelates differ in the nature and length of the linker connecting the cyclen-type macrocycle that binds the Ln(3+) ion and the crown ether. The complexes are monohydrated, but they exhibit high proton relaxivities (up to 7.7 mM(-1)  s(-1) at 60 MHz, 310 K) due to slow molecular tumbling. The formation of ternary complexes with neurotransmitters was monitored by (1) H relaxometric titrations of the Gd(3+) complexes and by luminescence measurements on the Eu(3+) and Tb(3+) analogues at pH 7.4. The remarkable relaxivity decrease (≈80 %) observed on neurotransmitter binding is related to the decrease in the hydration number, as evidenced by luminescence lifetime measurements on the Eu(3+) complexes. These complexes show affinity for amino acid neurotransmitters in the millimolar range, which can be suited to imaging concentrations of synaptically released neurotransmitters. They display good selectivity over non-amino acid neurotransmitters (acetylcholine, serotonin, and noradrenaline) and hydrogenphosphate, but selectivity over hydrogencarbonate was not achieved. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Facebook er internettet nu

    DEFF Research Database (Denmark)

    Tække, Jesper

    2014-01-01

    Den store vision for world wide web var, at alle kunne få ubegrænset adgang til alverdens information. www var mangfoldigt og anarkistisk. I dag er der rigtig mange, der kun bruger nettet til at være på Facebook. Hvad bruger Facebook det til? Og hvad gør det ved vores udsyn?......Den store vision for world wide web var, at alle kunne få ubegrænset adgang til alverdens information. www var mangfoldigt og anarkistisk. I dag er der rigtig mange, der kun bruger nettet til at være på Facebook. Hvad bruger Facebook det til? Og hvad gør det ved vores udsyn?...

  11. Two-step gamma cascades following thermal neutron capture in Gd-155,Gd-157

    Czech Academy of Sciences Publication Activity Database

    Valenta, S.; Bečvář, F.; Kroll, J.; Krtička, M.; Tomandl, Ivo

    2015-01-01

    Roč. 92, č. 6 (2015), s. 064321 ISSN 0556-2813 R&D Projects: GA ČR GA13-07117S; GA MŠk(CZ) LM2011019 Institutional support: RVO:61389005 Keywords : Ge detector * scattering * Gd-158 * Gd-157 Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 3.146, year: 2015

  12. Hvis er lovene?

    DEFF Research Database (Denmark)

    Holm, Isak Winkel

    2015-01-01

    Hvem konstituerer det politiske fællesskab, som laver lovene? Hvad sker der, når folket ikke kender lovene, eller ikke findes værdige til dem? Hvis folket udfordrede adelens love før i tiden, er det måske migranterne, der udfordrer europæernes love og konventioner i dag. Man kan med fordel gå til...... Franz Kafka for at forstå hvordan....

  13. Er havets iltminimumszoner iltfrie?

    DEFF Research Database (Denmark)

    Revsbech, Niels Peter; Larsen, Lars; Gundersen, Jens

    Den centrale del af havets ilt-minimumszoner kan være totalt iltfrie! Ved brug af STOX iltsensoren er det muligt at måle ilt med en detektionsgrænse nær 1 nM (dvs. en faktor 1000 bedre end hidtil muligt) og dermed at opnå en bedre forståelse af omsætningerne i oceanernes ilt-minimumszoner, der bl...

  14. Hvad er en by?

    DEFF Research Database (Denmark)

    Parby, Jakob; Thelle, Mikkel

    2011-01-01

    Nytænkning. Med de moderne megabyer er det slut med at forestille sig byen som noget, man planlægger og giver form. Vi skal lære at se dem som vildtvoksende urbane landskaber. Artikel om megabyer, byudvikling og forestillingen om byen gennem tiderne. Skrevet delvist i anledning af åbningen af uds...... udstillingen Citambulos på Københavns Museum, der handlede om Mexico City....

  15. Hvis er Himmeriget?

    DEFF Research Database (Denmark)

    Holst, Søren

    2007-01-01

    Udtrykket "de fattige i ånden", som kendes fra Bjergprædikenen i Matthæusevangeliet, forekommer også i to af Dødehavsrullerne. Artiklen undersøger disse tekster og argumenterer for, at udtrykket ikke betegner en særligt "åndelig" fattigdom, men derimod de konkret økonomisk fattige, som er "af ånd...

  16. Electronic and ionic transport in Ce0.8PrxTb0.2-xO2-δ and evaluation of performance as oxygen permeation membranes

    DEFF Research Database (Denmark)

    Chatzichristodoulou, Christodoulos; Hendriksen, Peter Vang

    2012-01-01

    is significantly enhanced relative to that of a Ce0.9Gd0.1O1.95-δ membrane at high oxygen activities of the permeate gas (aO2 an > 10-15) due to the enhanced electronic conductivity of the Ce0.8PrxTb0.2-xO2-δ compounds. Interference between the ionic and electronic flows has a significant positive effect......The electronic conductivity of Ce0.8PrxTb0.2-xO2-δ (x = 0, 0.05, 0.10, 0.15, 0.20) was determined in the oxygen activity range aO2 ≈ 103 to aO2 ≈ 10-17 at 700- 900 °C by means of Hebb-Wagner polarisation. The electronic conductivity of all the Ce0.8PrxTb0.2-xO2-δ compositions was significantly...... enhanced as compared to that of Ce0.9Gd0.1O1.95-δ, and its value was found to increase with increasing Pr/Tb ratio. The ionic mobility of Ce0.8PrxTb0.2-xO2-δ is similar to that of Ce1- 2δGd2δO2-δ at the same oxygen vacancy concentration. The calculated oxygen flux of a Ce0.8PrxTb0.2-xO2-δ membrane...

  17. Relationship between National TB program and prevalence of TB drug resistance in Algeria, 1965 to 2013

    Directory of Open Access Journals (Sweden)

    Fadila Boulahbal

    2015-01-01

    The different steps will be presented of the development of the National TB program in Algeria between 1964 and 2014, and in the same way the variations of the prevalence rate of TB drug resistance to demonstrate that the drug resistance surveillance is an acceptable indicator of the performance of TB control program in the country.

  18. TB incidence in an adolescent cohort in South Africa

    NARCIS (Netherlands)

    Mahomed, Hassan; Ehrlich, Rodney; Hawkridge, Tony; Hatherill, Mark; Geiter, Lawrence; Kafaar, Fazlin; Abrahams, Deborah Ann; Mulenga, Humphrey; Tameris, Michele; Geldenhuys, Hennie; Hanekom, Willem Albert; Verver, Suzanne; Hussey, Gregory Dudley

    2013-01-01

    Tuberculosis (TB) is a major public health problem globally. Little is known about TB incidence in adolescents who are a proposed target group for new TB vaccines. We conducted a study to determine the TB incidence rates and risk factors for TB disease in a cohort of school-going adolescents in a

  19. Detection of Multidrug Resistant Tuberculosis (MDR-TB) among ...

    African Journals Online (AJOL)

    A.I. Aminu, A.D. Tukur. Abstract. The Emergence of drug-resistant Mycobacterium tuberculosis strains especially multidrug resistant-TB (MDR-TB) and indeed extensively drug resistant TB (XDR-TB) is considered a real threat to achieving TB control. Thus, the WHO identified the need for accelerated access to rapid testing ...

  20. Stop TB in My Lifetime: A Call for a World Free of TB - World TB Day 2013

    Centers for Disease Control (CDC) Podcasts

    2012-03-12

    In this podcast Dr. Kenneth Castro, Director of the Division of Tuberculosis Elimination, discusses World TB Day, the 2013 slogan and theme.  Created: 3/12/2012 by National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention (NCHHSTP).   Date Released: 3/13/2012.

  1. Giant magnetocaloric effect in Gd5(Si2Ge2 alloy with low purity Gd

    Directory of Open Access Journals (Sweden)

    Cleber Santiago Alves

    2004-12-01

    Full Text Available Gd5(Ge1-xSi x, x < 4 based alloys are potential candidates for magnetic refrigeration in the range ~20 - ~290 K. However, one of the greatest obstacles for the use of that technology in large scale is the utilization of high pure Gd metal (99.99 wt. (% to produce the GdGeSi alloys, since the impurity elements decrease the intensity of the magnetocaloric effect (EMC¹. In this work, we prove that annealing of the Gd5Ge2Si2 can promote remarkable values for the EMC in comparison to those obtained for the alloy with high pure Gd. Also, the as cast alloy and the annealed alloy are not monophasic, but have at least two crystalline phases in their microstructure. Results for X-ray analysis, optical and electronic microscopy and magnetization measurements are reported.

  2. Comprehensive study of Pr-doped GdBa2Cu3O7-y system

    International Nuclear Information System (INIS)

    Yamani, Z.; Akhavan, M.

    1997-01-01

    An extensive study of the magnetic, electrical transport, and structural properties of the normal and superconducting states of Gd 1-x Pr x Ba 2 Cu 3 O 7-y (GdPr-123) is presented. Ceramic compounds have been synthesized by the solid state reaction technique, and characterized by XRD, SEM, TGA, and DT techniques. The parent compound GdBa 2 Cu 3 O 7-y (Gd-123) is a high-T c superconductor and the endpoint compound, PrBa 2 Cu 3 O 7-y (Pr-123) is a magnetic insulator, both having the crystal structures isomorphic to the 123 phase structure. The superconducting transition temperature is reduced with increasing Pr content in a non-linear manner, in contrast to the Abrikosov-Gorkov pair breaking theory. A metal-insulator transition is observed at the critical Pr content, x er ∼0.45, at which superconductivity completely disappears. Magnetic susceptibility measurements show that the nominal Pr valence is 3.86+, independent of the Pr content. The metal-insulator transition in this system is similar to that in the oxygen-deficient RBa 2 Cu 3 O 7-y (R-123) system. Based on this resemblance, we suggest that Pr doping reduces the carrier concentration (either by hole filling/localization or changes in the band structure) similar to the deoxygenated case. Hence, the environment surrounding the Cu-O layers is important to high-T c superconductivity (HTSC). In this sense, HTSC cannot completely be two dimensional feature. A chain-plane correlation (CPC) effect is plausible. The normal state conduction mechanism has been interpreted by the quantum percolation theory based on localized states. Localization is probably caused by the Pr valence fluctuations in the GdPr-123 system. (orig.)

  3. Magnetic ordering of GdMn2

    International Nuclear Information System (INIS)

    Ouladdiaf, B.; Ritter, C.; Ballou, R.; Deportes, J.

    1999-01-01

    Complete text of publication follows. GdMn 2 crystallizes in the C15 cubic Laves phase structure. Within this structure Mn atoms lie at the vertices of regular tetrahedra stacked in the diamond arrangement connected by sharing vertices, leading to a strong geometric frustration. An antiferromagnetic magnetic order sets in below T N ∼ 105 K. It gives rise to a large magnetovolume effect (ΔV/V ∼ 1%). Thermal expansion data show two anomalies at 105 K and 35 K. The second anomaly was often interpreted as the ferromagnetic ordering of Gd sublattice. Moessbauer data indicate however, that Gd sublattice orders at T N ∼ 105 K as the Mn moments. Elastic neutron scattering measurements were performed using short wavelength neutron beam (λ = 0.5 A) on D9 at ILL. No magnetic contribution to the nuclear peaks was found excluding thereby any K = [0 0 0] component. However antiferromagnetic peaks indexed by a propagation vector [2/3 2/3 0] were observed leading to a non collinear magnetic arrangement of both Mn and Gd sublattices. The results are discussed by invoking the geometric frustration associated with the Mn atomic packing and the singlet state of the Gd ions. (author)

  4. TB Testing for People Living with HIV

    Centers for Disease Control (CDC) Podcasts

    2012-07-23

    Dr. Kenneth Castro, Director of the Division of Tuberculosis Elimination, explains why it is important for people living with HIV to be tested for TB.  Created: 7/23/2012 by National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention (NCHHSTP).   Date Released: 7/23/2012.

  5. Luminescence of YAG:Tm, Tb

    International Nuclear Information System (INIS)

    Scholl, M.S.; Trimmier, J.R.

    1986-01-01

    Two rare earth cations, thulium (Tm) and terbium (Tb) have been incorporated into a yttrium aluminum garnet (YAG) host material to obtain a blue phosphor. Thulium concentrations of up to 5% yield a saturated dark blue phosphor which exhibits a low efficiency. The highest efficiency for YAG:Tm occurs at a Tm concentration of 2%. A 0.5% concentration of terbium yields an unsaturated blue phosphor with an efficiency of approximately a factor of 15 times greater than that of Tm. The cathodoluminescence spectrum of YAG:Tm, Tb depicts features identifiable with YAG:Tb even at low Tb concentrations (0.5%). The light emitted by a Tb, Tm coactivated phosphor exhibits a clear shift toward the green region of the spectrum. There appears to be a resonant energy transfer from the 1 D 2 Tm 3+ state to the 5 D 4 Tb 3+ state. In the case of small concentrations of Tb in YAG, thulium behaves as a sensitizer for Tb cathodoluminescence

  6. Diagnosis of active TB using aptamers

    CSIR Research Space (South Africa)

    Khati, M

    2013-08-01

    Full Text Available ) and the 6-kDa early secreted antigen target (ESAT-6), which are potent T-cell antigens that are recognised by over 70% of TB patients. We then used these aptamers to develop a TB diagnostic tool that can be used at point-of-care for early and rapid detection...

  7. Thermal properties of UO2 - Gd2O3 fuel

    International Nuclear Information System (INIS)

    Kim, G. S.; Yang, J. H.; Kang, K. W.; Kim, Y. M.; Song, G. W.

    2000-01-01

    The thermal properties (thermal conductivity, oxygen potential and thermal expansion) of UO 2 -Gd 2 O 3 fuels were measured by the laser-flash, TGA and dilatometry method. The thermal conductivity decreased with Gd content, but the oxygen potential and thermal expansion increased with Gd content. Substitution of Gd +3 ion in UO 2 structure increases the scattering site for thermal phonon propagation and thereby decreases the thermal conductivity. The oxygen potential of Gd-doped UO 2 increase mainly because the Gd +3 ions, which are inert to oxidation, make it difficult for oxygen interstitials to access just near them

  8. Gd(III)-nanodiamond conjugates for MRI contrast enhancement

    Science.gov (United States)

    Manus, Lisa M.; Mastarone, Daniel J.; Waters, Emily A.; Zhang, Xue-Qing; Schultz-Sikma, Elise A.; MacRenaris, Keith W.; Ho, Dean

    2010-01-01

    A Gd(III)-nanodiamond conjugate [Gd(III)-ND] was prepared and characterized, enabling detection of nanodiamonds by MR imaging. The Gd(III)-ND particles significantly reduced the T1 of water protons with a per-Gd(III) relaxivity of 58.82 ± 1.18 mM−1s−1 at 1.5 Tesla (60 MHz). This represents a tenfold increase compared to the monomer Gd(III) complex (r1 = 5.42 ± 0.20 mM−1s−1) and is among the highest per-Gd(III) relaxivities reported. PMID:20038088

  9. Tuberculosis: The Connection between TB and HIV (the AIDS Virus)

    Science.gov (United States)

    ... Studies Consortium Research Projects Publications TB Trials Consortium Study Descriptions Background Behavioral & Social Science Research Infection Control TB in Specific Populations African-American Community Stop TB in the African-American ...

  10. High-pressure structural behavior of GdAlO3 and GdFeO3 perovskites

    International Nuclear Information System (INIS)

    Ross, N.L.; Zhao, J.; Angel, R.J.

    2004-01-01

    The orthorhombic perovskites, GdAlO 3 and GdFeO 3 , have been studied using single-crystal X-ray diffraction up to 8.52 and 8.13GPa, respectively, in a diamond anvil cell at 298K. The evolution of the structures of GdAlO 3 and GdFeO 3 involves compression of both the GdO 12 and the octahedral (AlO 6 and FeO 6 ) sites. The compression of the GdO 12 site is anisotropic in both perovskites, with the four longest Gd-O distances compressing more than the eight shorter Gd-O bond lengths, resulting in a decrease in the distortion of GdO 12 with pressure. In GdAlO 3 , the GdO 12 site is less compressible than the AlO 6 site, resulting in an increase of both the interoctahedral Al-O1-Al and Al-O2-Al angles with increasing pressure. Thus GdAlO 3 perovskite becomes less distorted with increasing pressure. In GdFeO 3 , the GdO 12 site displays a similar compressibility as the FeO 6 site, with little change in the Fe-O2-Fe angle with pressure but an increase of the Fe-O1-Fe tilting angle. Thus GdFeO 3 perovskite becomes less distorted with increasing pressure, but the change is not as pronounced as GdAlO 3 . The high-pressure behavior of GdAlO 3 and GdFeO 3 is similar to orthorhombic YAlO 3 perovskite but contrasts with orthorhombic CaSnO 3 , which becomes more distorted with increasing pressure

  11. Hvad er tekstfiktion?

    DEFF Research Database (Denmark)

    Widell, Peter

    2012-01-01

    artiklen er et bidrag til belysningen af genteori og bygger på ideen om at karakterisere skønlitteratur som et restringeret sæt af universelle tekstparametre. Artiklen fokuserer især på parametren tekstfiktion, hvor jeg forsvarer den position, at en fiktiv tekst hverken kan karakteriseres som en ...... intentioner. Det betyder dog ikke, at sandhed og mening ikke spiller noget rolle ved identifikationen af fiktion, sådan som det hævdes af Walsh og andre....

  12. Unoccupied surface electronic structure of Gd(0001)

    International Nuclear Information System (INIS)

    Li, D.; Dowben, P.A.; Ortega, J.E.; Himpsel, F.J.

    1994-01-01

    The unoccupied surface electronic structure of Gd(0001) was investigated with high-resolution inverse-photoemission spectroscopy. An empty surface state near E F is observed at bar Γ. Two other surface-sensitive features are also revealed at 1.2 and 3.1 eV above the Fermi level. Hydrogen adsorption on Gd surfaces was used to distinguish the surface-sensitive features from the bulk features. The unoccupied bulk-band critical points are determined to be Γ 3 + at 1.9 eV and A 1 at 0.8 eV

  13. Experimental MR imaging with Gd-DOTA: Preliminary results

    International Nuclear Information System (INIS)

    Schouman-Claeys, E.; Kien, P.; Caille, J.M.; Bonnemain, B.; Frija, G.

    1986-01-01

    To evaluate the paramagnetic properties of a new gadolinium chelate, Gd-DOTA, in vitro and in vivo MR imaging was performed with a 0.5-T supraconductive magnet. The in vitro study consisted in measuring the MR signal obtained with various concentrations of Gd-DOTA and Gd-DTPA in different solutions. Potentialization of the paramagnetic properties of both DOTA and DTPA can be achieved by deuterium, glycerol, and protein solutions. The in vivo study was performed in rabbits with various experimental lesions. Enhancement of anatomic details was obtained with both Gd-DOTA and Gd-DTPA. There was no significant difference between Gd-DOTA and Gd-DTPA, both for in vitro and in vivo experiments. Gd-DOTA appears to be a potential paramagnetic agent for MR imaging

  14. Progress and challenges in TB vaccine development.

    Science.gov (United States)

    Voss, Gerald; Casimiro, Danilo; Neyrolles, Olivier; Williams, Ann; Kaufmann, Stefan H E; McShane, Helen; Hatherill, Mark; Fletcher, Helen A

    2018-01-01

    The Bacille Calmette Guerin (BCG) vaccine can provide decades of protection against tuberculosis (TB) disease, and although imperfect, BCG is proof that vaccine mediated protection against TB is a possibility. A new TB vaccine is, therefore, an inevitability; the question is how long will it take us to get there? We have made substantial progress in the development of vaccine platforms, in the identification of antigens and of immune correlates of risk of TB disease. We have also standardized animal models to enable head-to-head comparison and selection of candidate TB vaccines for further development.  To extend our understanding of the safety and immunogenicity of TB vaccines we have performed experimental medicine studies to explore route of administration and have begun to develop controlled human infection models. Driven by a desire to reduce the length and cost of human efficacy trials we have applied novel approaches to later stage clinical development, exploring alternative clinical endpoints to prevention of disease outcomes. Here, global leaders in TB vaccine development discuss the progress made and the challenges that remain. What emerges is that, despite scientific progress, few vaccine candidates have entered clinical trials in the last 5 years and few vaccines in clinical trials have progressed to efficacy trials. Crucially, we have undervalued the knowledge gained from our "failed" trials and fostered a culture of risk aversion that has limited new funding for clinical TB vaccine development. The unintended consequence of this abundance of caution is lack of diversity of new TB vaccine candidates and stagnation of the clinical pipeline. We have a variety of new vaccine platform technologies, mycobacterial antigens and animal and human models.  However, we will not encourage progression of vaccine candidates into clinical trials unless we evaluate and embrace risk in pursuit of vaccine development.

  15. The TB epidemic from 1992 to 2002.

    Science.gov (United States)

    Raviglione, Mario C

    2003-01-01

    In 1992, less than 20 countries were implementing a sound TB control strategy. At the same time, TB was being resurrected as a major public health problem world-wide after two decades of neglect. Awareness of upward trends in the industrialized countries and MDR-TB outbreaks in large cities were driving forces behind the re-emergence of TB in the international health agenda. New evidence, and consequent estimates, suggested that the situation in developing countries, especially in sub-Saharan Africa, was deteriorating rapidly. Similarly, major increases were observed in the former USSR. It was estimated that some 7-8 million new cases and 2-3 million deaths were occurring annually in the world. The global targets of reaching 85% cure rates and 70% case detection among infectious cases were established by the World Health Assembly in 1991. Both the WHO declaration of TB as a global emergency in 1993 and the launch of the five-element DOTS strategy in 1994-1995 resulted in countries adopting DOTS in encouraging numbers. In fact, in 2000, 148 countries including all 22 highest burden countries (HBC) responsible for 80% of cases world-wide, had adopted the new DOTS strategy. Nevertheless, progress in case detection remained slow due to incomplete geographical coverage or need to widen detection and notification capacity with innovative schemes. The major constraints to TB control became increasingly clear, and a global Stop TB Partnership was eventually established to address such constraints. A Global DOTS Expansion Plan revealed the needs and the gaps to achieve the global targets in 2005. Today, in 2002, the top priority remains that of expanding DOTS, as rapidly as possible, using a number of new approaches to increase case detection and notification while maintaining high cure rates. These must involve collaboration with the private sector and communities, as well as strengthening of primary care services. Similarly, crucial is the rapid identification of

  16. Strongly coupled band in {sup 140}Gd

    Energy Technology Data Exchange (ETDEWEB)

    Falla-Sotelo, F.; Oliveira, J.R.B.; Rao, M.N. [Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo (Brazil)] (and others)

    2005-07-01

    Several high-K states are known to exist in the mass 130-140 region. For the N=74 even-even isotopes, K{pi} = 8{sup -} isomers, with lifetimes ranging from ns to ms, are known in {sup 128}Xe, {sup 130}Ba, {sup 132}Ce, {sup 134}Nd, {sup 136}Sm, and {sup 138}Gd[. In {sup 140}Gd, we have observed for the first time a band also based on an I{pi} = 8{sup -} state. This could be the first case of a K{pi} = 8{sup -} state observed in an N=76 even-even isotope. The systematics of the K{pi} = 8{sup -} isomeric states in N=74 isotopes has been studied by A.M. Bruce et al. These states decay towards the K = 0 ground state band, and the transitions are K-forbidden. The {sup 140}Gd case presents strong similarities but also some significant differences with relation to the N=74 isotopes. We propose the same configuration but with larger deformation in {sup 140}Gd.

  17. GdNCT of spontaneous canine melanoma

    International Nuclear Information System (INIS)

    Mitin, V.N.; Kulakov, V.N.; Khokhlov, V.F.

    2006-01-01

    The effectiveness of GdNCT has been studied in dogs with spontaneous melanoma of the mucousmembrane of the oral cavity patients on the NCT base at the IRT MEPhI reactor. The control group with melanomas was treated with neutrons. Fourteen canine patients were selected in the Clinic of Experimental Therapy affiliated with the RCRC RAMS. The calculation of doses has shown that the total dose of energy release depending on Gd concentration in the target can be several times higher than the dose produced by the reactor neutron beam. The calculations were carried out using the diffusion pharmacokinetic model. The gadolinium drug dipentast was administered intratumorally immediately prior to irradiation. The tumor size was estimated by measuring it in three projections. The tumor was irradiated for 60-90 minutes with a thermal neutron flux of 0.7x10 9 n/cm 2 s. The dose on tumor was 80-120 Gy, on surrounding tissues - 12-15 Gy. The treatment plan included immunotherapy with Roncoleikin in a dose of (15-10)x10 3 IE/kg. The results of GdNCT are still under observation. The results conform to those obtained by us earlier in cell cultures and inoculated experimental tumors. GdNCT is also effective in combination with immunotherapy. (author)

  18. Theoretical Magnon Dispersion Curves for Gd

    DEFF Research Database (Denmark)

    Lindgård, Per-Anker; Harmon, B. N.; Freeman, A. J.

    1975-01-01

    The magnon dispersion curve of Gd metal has been determined from first principles by use of augmented-plane-wave energy bands and wave functions. The exchange matrix elements I(k⃗, k⃗′) between the 4f electrons and the conduction electrons from the first six energy bands were calculated under...

  19. Magnetic short range order in Gd

    International Nuclear Information System (INIS)

    Child, H.R.

    1976-01-01

    Quasielastic neutron scattering has been used to investigate magnetic short range order in Gd for 80 0 K 0 K. Short range order exists throughout this range from well below T/sub C/ = 291 0 K to well above it and can be reasonably well described by an anisotropic Orstein-Zernike form for chi

  20. Gd-substituted Bi-2223 superconductor

    Indian Academy of Sciences (India)

    The effects of gadolinium doping at calcium site on the normal and super- conducting properties of Bi-2223 system were ... quantities of the metal oxides and the carbonates were taken and thoroughly mixed. The calcination of the mixture after .... Therefore, Gd has higher solubility in (BiPb)-2223 as compared to Pr, and is, ...

  1. Sensitisation of Eu(III)- and Tb(III)-based luminescence by Ir(III) units in Ir/lanthanide dyads: evidence for parallel energy-transfer and electron-transfer based mechanisms.

    Science.gov (United States)

    Sykes, Daniel; Cankut, Ahmet J; Ali, Noorshida Mohd; Stephenson, Andrew; Spall, Steven J P; Parker, Simon C; Weinstein, Julia A; Ward, Michael D

    2014-05-07

    A series of blue-luminescent Ir(III) complexes with a pendant binding site for lanthanide(III) ions has been synthesized and used to prepare Ir(III)/Ln(III) dyads (Ln = Eu, Tb, Gd). Photophysical studies were used to establish mechanisms of Ir→Ln (Ln = Tb, Eu) energy-transfer. In the Ir/Gd dyads, where direct Ir→Gd energy-transfer is not possible, significant quenching of Ir-based luminescence nonetheless occurred; this can be ascribed to photoinduced electron-transfer from the photo-excited Ir unit (*Ir, (3)MLCT/(3)LC excited state) to the pendant pyrazolyl-pyridine site which becomes a good electron-acceptor when coordinated to an electropositive Gd(III) centre. This electron transfer quenches the Ir-based luminescence, leading to formation of a charge-separated {Ir(4+)}˙-(pyrazolyl-pyridine)˙(-) state, which is short-lived possibly due to fast back electron-transfer (transfer pathway is again operative and leads to sensitisation of Eu-based and Tb-based emission using the energy liberated from the back electron-transfer process. In addition direct Dexter-type Ir→Ln (Ln = Tb, Eu) energy-transfer occurs on a similar timescale, meaning that there are two parallel mechanisms by which excitation energy can be transferred from *Ir to the Eu/Tb centre. Time-resolved luminescence measurements on the sensitised Eu-based emission showed both fast and slow rise-time components, associated with the PET-based and Dexter-based energy-transfer mechanisms respectively. In the Ir/Tb dyads, the Ir→Tb energy-transfer is only just thermodynamically favourable, leading to rapid Tb→Ir thermally-activated back energy-transfer and non-radiative deactivation to an extent that depends on the precise energy gap between the *Ir and Tb-based (5)D4 states. Thus, the sensitised Tb(iii)-based emission is weak and unusually short-lived due to back energy transfer, but nonetheless represents rare examples of Tb(III) sensitisation by a energy donor that could be excited using visible

  2. World TB Day 2018: The Challenge of Drug Resistant Tuberculosis.

    Science.gov (United States)

    Gupta-Wright, Ankur; Tomlinson, Gillian S; Rangaka, Molebogeng X; Fletcher, Helen A

    2018-01-01

    On 24th March, the world commemorates the day in 1882 when Dr Robert Koch announced his discovery of Mycobacterium tuberculosis (MTB). Over 130 years later, tuberculosis (TB) continues to affect individuals, communities, and entire health systems and economies. Koch unsuccessfully tried to 'cure' TB, and despite major advances in other areas of medicine, control of TB remains elusive- in 2016 TB was the leading infectious cause of death. The STOP TB partnership and World Health Organization (WHO) have announced their theme for World TB Day 2018 "Wanted: Leaders for a TB-Free World. You can make history. End TB." This theme recognizes that TB is much larger than any one person, institute or discipline of research, and provides an opportunity for us to reflect on the major challenges and consider how we, as a scientific community, can work together and take the lead to address the global crisis of drug-resistant TB (DR-TB).

  3. Rouw mag er zijn

    Directory of Open Access Journals (Sweden)

    Marlieke Moors

    2015-12-01

    Full Text Available ABSTRACTGrieving is allowedGrief is a human experience. Every form of loss shapes you into the human being you are today. Contrary to what earlier, unproven grief models postulate, grief does not have an end point. That is, bereavement does not have to be completely processed, but it should be integrated into someone’s life. The outdated grief models were often interpreted and used in a normative way, which led to a normative standard model. This portraits the belief that every mourner would experience similar symptoms and would go through a fixed pattern of phases. However, the updated vision emphasizes the individual and unique process of coping with loss: norms concerning grief should be banned. By means of literature research, interviews with professionals and personal experiences, it became clear that finding an equilibrium between restoration-orientated and loss-orientated coping styles is most beneficial. An important aspect in finding this balance is meaningfulness. Furthermore, the ability to bear a loss and to adapt accordingly are important components. Lastly, attaching significance to a loss is a constructive way of integrating the loss into one’s life. The death of a loved one should therefore not be forgotten or tucked away. After all, grief is the price we pay for love. SAMENVATTINGRouw mag er zijnRouw is een menselijke ervaring en elk verlies vormt je als mens. Rouw heeft, in tegenstelling tot wat de verouderde, niet bewezen rouwmodellen beweren, geen eindpunt. Verlies hoeft namelijk niet verwerkt te worden, maar moet juist geïntegreerd worden in iemands leven. De verouderde rouwmodellen zijn vaak normatief opgevat en toegepast, waaruit een normatief standaardmodel is ontstaan. Daarbij werd gedacht dat elke rouwende dezelfde symptomen zou vertonen en het rouwproces volgens vaste fasen zou verlopen. Binnen de vernieuwde visie wordt er juist van uitgegaan dat elk individu een unieke manier van reageren op rouw heeft. Er zou

  4. Alt er ændret. Intet er afklaret

    DEFF Research Database (Denmark)

    Helmersen, Ole

    2017-01-01

    Brexit kan redefinere landets internationale rolle lige så meget som Suezkrisen. Men 15 måneder efter afstemningen er der stadig ingen svar.......Brexit kan redefinere landets internationale rolle lige så meget som Suezkrisen. Men 15 måneder efter afstemningen er der stadig ingen svar....

  5. Luminescent properties of Tb doped gadolinium aluminate nanophosphors for display and forensic applications

    Directory of Open Access Journals (Sweden)

    P.K. Jisha

    2017-12-01

    Full Text Available A novel green light emitting GdAlO3:Tb3+ (1–11 mol% nanophosphor has been synthesized by the solution combustion method and the final products were characterized. The energy band gap of the samples was estimated in the range of 5.13–5.88 eV from diffuse reflectance spectra. The effect of the added Tb3+ ions on the electronic structure was considered based on the absolute electronegativity. The characteristic photoluminescence emission corresponding to the transition 5D4→7Fj (j = 6, 5, 4, 3 of the Tb3+ ions was observed in the wavelength range of 500–650 nm, and assigned due to the f–f transitions upon the 378 nm excitation. The optimized nanophosphor was found suitable for applications in the latent fingerprint detection. The photometric characterization has revealed the excellent color chromaticity coordinates and the correlated color temperature levels. They are on the same level of commercial phosphors and quite useful for green WLEDs, solid state displays and forensic applications as well.

  6. Er talesprog en medieteknologi?

    DEFF Research Database (Denmark)

    Tække, Jesper

    2013-01-01

    for den menneskelige udfoldelse. Til at løse denne opgave vil jeg trække på den tyske sociolog og systemteoretiker Niklas Luhmann der også udmærker sig som medieteoretiker (Tække 2006a). Luhmann har ikke selv direkte redegjort for sprog som teknologi, men da han både har udviklet et brugbart...... motiver og viden, må give mening til hvad, der meddeles og selektere en forståelse (Luhmann 2000a). Formålet med og berettigelsen for medieteori er ud fra Marshall McLuhans (1967) devise, om at the medium is the message, at sammenligne, hvad det betyder for menneske og samfund, at der kommunikeres i ét...

  7. Direct measurement of the magnetocaloric effect of microstructured Gd eutectic compounds using a new fast automatic device

    Science.gov (United States)

    Canepa, Fabio; Cirafici, Salvino; Napoletano, Myrta; Ciccarelli, Carlo; Belfortini, Claudio

    2005-01-01

    A newly designed experimental device for direct measurement of the magnetocaloric effect has been assembled and tested. Details about calibration and preliminary measurements performed on Gd as a standard reference material are reported together with results concerning the magnetocaloric effect of three different Gd eutectic compositions (Gd-Gd 7Pd 3, Gd-GdZn, Gd-GdCd).

  8. Host markers in Quantiferon supernatants differentiate active TB from latent TB infection: preliminary report

    Directory of Open Access Journals (Sweden)

    Walzl Gerhard

    2009-05-01

    Full Text Available Abstract Background Interferon gamma release assays, including the QuantiFERON® TB Gold In Tube (QFT have been shown to be accurate in diagnosing Mycobacterium tuberculosis infection. These assays however, do not discriminate between latent TB infection (LTBI and active TB disease. Methods We recruited twenty-three pulmonary TB patients and 34 household contacts from Cape Town, South Africa and performed the QFT test. To investigate the ability of new host markers to differentiate between LTBI and active TB, levels of 29 biomarkers in QFT supernatants were evaluated using a Luminex multiplex cytokine assay. Results Eight out of 29 biomarkers distinguished active TB from LTBI in a pilot study. Baseline levels of epidermal growth factor (EGF soluble CD40 ligand (sCD40L, antigen stimulated levels of EGF, and the background corrected antigen stimulated levels of EGF and macrophage inflammatory protein (MIP-1β were the most informative single markers for differentiation between TB disease and LTBI, with AUCs of 0.88, 0.84, 0.87, 0.90 and 0.79 respectively. The combination of EGF and MIP-1β predicted 96% of active TB cases and 92% of LTBIs. Combinations between EGF, sCD40L, VEGF, TGF-α and IL-1α also showed potential to differentiate between TB infection states. EGF, VEGF, TGF-α and sCD40L levels were higher in TB patients. Conclusion These preliminary data suggest that active TB may be accurately differentiated from LTBI utilizing adaptations of the commercial QFT test that includes measurement of EGF, sCD40L, MIP-1β, VEGF, TGF-α or IL-1α in supernatants from QFT assays. This approach holds promise for development as a rapid diagnostic test for active TB.

  9. HIV-Associated TB: Facts 2013

    Science.gov (United States)

    ... 2012 . Around 75% of these people live in sub-Saharan Africa.  TB is the leading cause of death among ... adopted by policy makers and implemented by all health facilities offering HIV care services.  The number of ...

  10. De 9 P’er

    DEFF Research Database (Denmark)

    Rennison, Betina Wolfgang

    2017-01-01

    Ledere skal i dag selv skabe deres eget rum til ledelse, men hvad er med til at sætte det, hvilke betingelser og udfordringer er der, og hvordan kan lederne skabe sig selv i et hav af forventninger? Dette katalog inviterer til refleksion herom....

  11. Fremtidens undervisningsmiljøer

    DEFF Research Database (Denmark)

    2013-01-01

    Som oplægget til dette temanummer af LOM også indikerede, så sætter vi fokus på fremtidens undervisningsmiljøer på universiteter og UCer. Fremtidens undervisningsmiljøer har mange facetter, hvilket samlingen af artikler også illustrerer. “Fremtidens Undervisningsmiljø” handler om eksisterende erf...

  12. RNA er jo bare matematik!

    DEFF Research Database (Denmark)

    Blaavand, Jakob Lindblad

    2011-01-01

    Hvordan kan man kurere sygdomme med matematiske geometriske strukturer? Det kan man i princippet, hvis de geometriske figurer er RNA-molekyler, og sygdommen skyldes syge gener.......Hvordan kan man kurere sygdomme med matematiske geometriske strukturer? Det kan man i princippet, hvis de geometriske figurer er RNA-molekyler, og sygdommen skyldes syge gener....

  13. Kollegaerne er den nye chef

    DEFF Research Database (Denmark)

    Fugl, Marie

    2008-01-01

    Den tid, hvor chefen var den, der delte skideballer ud, er slut. Rollen som 'bad cop' er overtaget af kollegateamet, der med hård hånd sørger for, at den enkelte yder sin del. Udgivelsesdato: November...

  14. Den rige personlighed er livsduelig

    DEFF Research Database (Denmark)

    Holm, Claus

    2015-01-01

    For omtrent 160 år siden formulerede Karl Marx forestillingen om en rig individualitet som det kommunistiske samfunds individideal. I dag får forestillingen relevans. Lyder det lidt besynderligt, er det ikke mærkeligt. For de fleste af os går næppe rundt og tror, at vi er lige på trapperne til...

  15. Fraflytning er ikke en naturlov

    DEFF Research Database (Denmark)

    Nørgaard, Helle

    2015-01-01

    DEBAT: Der er brug for en erkendelse af, at det ikke er en naturlov, at folk vil flytte til byerne. Forskning viser, at børnefamilier finder tryghed og ideelle rammer for familielivet på landet. Det skriver Helle Nørgaard, seniorforsker, ph.d., Statens Byggeforskningsinstitut, Aalborg Universitet....

  16. Følelsen er alt

    DEFF Research Database (Denmark)

    Bonde, Lisbeth

    forrige sekelskifte. Det gælder især de ofte mennesketomme landskabsmalerier med ensomme kastanjetræer, som sukker i efterårslyset, og parkerne med de undertiden flygtige menneskeskikkelser, der som partikler kan forsvinde i vinden. Det er alt sammen skildret med vibrerende, næsten ’sfumatiske’ konturer...

  17. Humor er en alvorlig sag

    DEFF Research Database (Denmark)

    Søltoft, Pia

    2016-01-01

    I modsætning til ironi er humor for Kierkegaard fællesskabsgivende – ironikeren hævder sig selv, men humoristen har sympati med den, man ler med. Humor er hos Kierkegaard udtryk for, at humoristen forliger sig med tilværelsen og dens luner, og dermed grænser humoren hos Kierkegaard op til det...

  18. Standards for TB care in India: A tool for universal access to TB care.

    Science.gov (United States)

    Nair, Sreenivas Achuthan; Sachdeva, K S; Malik, Parmar; Chandra, S; Ramachandran, R; Kulshrestha, N; Chopra, K K; Khaparde, S D

    2015-10-01

    In 2014, Government of India in collaboration with World Health Organization Country Office for India released the policy document on Standards for tuberculosis (TB) care in India after in-depth deliberation with national and international experts. The standards for TB care represent what is expected for quality TB care from the Indian healthcare system including both public and private systems. The details of each standard have been compiled in this review article. It is envisioned that the standards detailed in the manuscript are adapted by all TB care providers across the country. Copyright © 2015 Tuberculosis Association of India. Published by Elsevier B.V. All rights reserved.

  19. The effects of Tb 3+ doping concentration on luminescence ...

    Indian Academy of Sciences (India)

    Engineering Research Center of Optoelectronic Functional Materials of the Ministry of Education,. Changchun University of Science and Technology, Changchun 130022, PR China .... which are dependent on the distance among Tb3+ ions. The interaction of Tb3+–Tb3+ is dependent on the dis- tance among Tb3+ ions.

  20. Migration, TB control and elimination: Whom to screen and treat.

    Science.gov (United States)

    Rendon, A; Centis, R; Zellweger, J-P; Solovic, I; Torres-Duque, C A; Robalo Cordeiro, C; de Queiroz Mello, F C; Manissero, D; Sotgiu, G

    Tuberculosis (TB) in migrants represents an important clinical and public health threat, particularly in low TB incidence countries. The current review is aimed to assess issues related to screening and treatment of migrants with latent TB infection or TB disease. Copyright © 2017 Sociedade Portuguesa de Pneumologia. Published by Elsevier España, S.L.U. All rights reserved.

  1. The effects of Tb 3 doping concentration on luminescence properties ...

    Indian Academy of Sciences (India)

    This paper is aimed at explaining the effects of Tb3+ concentration on structure and luminescence properties and clarifying the concentration quenching mechanism of Tb3+. The lattice of BaF2 decreases with the increase of Tb3+ ions concentration. The emission spectrum of BaF2:Tb3+ consists of blue emission band and ...

  2. Calculation of the band structure of GdCo2, GdRh2 e GdIr2 by the APW method

    International Nuclear Information System (INIS)

    Carvalho, J.A.B. de.

    1974-03-01

    The band structure of GdCo 2 , GdRh 2 , GdIr 2 has been calculated by the APW method. A histogram of the density of states is presented for each compound. The bands are transition-metal-like, with s-d hybridization near the Fermi level. The 5d character near the Fermi level increases as one goes from Co to Ir

  3. Structural and electronic properties of Er-monopnictides under high pressure

    International Nuclear Information System (INIS)

    Pandit, Premlata; Srivastava, Vipul; Rajagopalan, M.; Sanyal, Sankar P.

    2010-01-01

    We present the results of theoretical calculations on the structural, magnetic and electronic properties of Er-monopnictides using self-consistent first principles tight-binding linear-muffin-tin-orbital (TB-LMTO) method within the atomic-sphere approximation (ASA). Both spin-polarized and non-spin-polarized calculations are performed to check the magnetic stability of these compounds. We find that ErN, ErP and ErAs are metallic in ferromagnetic (FM) phase in both the spin channels and stable in NaCl-type (B 1 ) structure at ambient pressure. We predict NaCl-type (B 1 ) to CsCl-type (B 2 ) structural phase transition in ErN, ErP and ErAs at pressures of 146.1, 60.2 and 53.2 GPa, respectively and remain metallic ferromagnetic at high pressure. We calculate equilibrium lattice constants (a), bulk modulus (B), magnetic moments (μ B ) and electronic properties of these compounds in B 1 and B 2 phases and compare with available experimental and theoretical results.

  4. CW laser properties of Nd:GdYAG, Nd:LuYAG, and Nd:GdLuAG mixed crystals

    Science.gov (United States)

    Di, J. Q.; Xu, X. D.; Li, D. Z.; Zhou, D. H.; Wu, F.; Zhao, Z. W.; Xu, J.; Tang, D. Y.

    2011-10-01

    Three mixed crystals, Nd:GdYAG, Nd:LuYAG, and Nd:GdLuAG, were grown by Czochralski method. We report the continuous-wave (CW) Nd:GdYAG, Nd:LuYAG, and Nd:GdLuAG laser operation under laser diode pumping. The maximum output powers are 4.11, 5.31, and 7.47 W, with slope efficiency of 73.0, 55.3, and 57.1%, respectively. With replacing Lu3+ or Y3+ ions with large Gd3+ ions, the pump efficiency increases.

  5. A multiplexed and miniaturized serological tuberculosis assay identifies antigens that discriminate maximally between TB and non-TB sera

    NARCIS (Netherlands)

    Tong, Miao; Jacobi, Catharina E.; van de Rijke, Frans M.; Kuijper, Sjoukje; van de Werken, Sjaak; Lowary, Todd L.; Hokke, Cornelis H.; Appelmelk, Ben J.; Nagelkerke, Nico J. D.; Tanke, Hans J.; van Gijlswijk, Rob P. M.; Veuskens, Jacques; Kolk, Arend H. J.; Raap, Anton K.

    2005-01-01

    We have developed a multiplexed and miniaturized TB serological assay with the aim of identifying (combinations of) antigens that maximally discriminate between TB and non-TB patients. It features a microarray accommodating 54 TB antigens, less than 1 microl serum consumption and an indirect

  6. Gd-substituted Bi-2223 superconductor

    Indian Academy of Sciences (India)

    resistivity with a view to study metal-to-insulator transition, (2) the XRD patterns of the specimens with a view to study the .... values [4] of the transition temperatures for Gd-substituted (BiPb)-2212 specimens. The specimens of Batches I and II with x > 0.4 .... (retd) P N Dheer and Dr R G Sharma. 540. Pramana – J. Phys., Vol.

  7. TB incidence in an adolescent cohort in South Africa.

    Directory of Open Access Journals (Sweden)

    Hassan Mahomed

    Full Text Available BACKGROUND: Tuberculosis (TB is a major public health problem globally. Little is known about TB incidence in adolescents who are a proposed target group for new TB vaccines. We conducted a study to determine the TB incidence rates and risk factors for TB disease in a cohort of school-going adolescents in a high TB burden area in South Africa. METHODS: We recruited adolescents aged 12 to 18 years from high schools in Worcester, South Africa. Demographic and clinical information was collected, a tuberculin skin test (TST performed and blood drawn for a QuantiFERON TB Gold assay at baseline. Screening for TB cases occurred at follow up visits and by surveillance of registers at public sector TB clinics over a period of up to 3.8 years after enrolment. RESULTS: A total of 6,363 adolescents were enrolled (58% of the school population targeted. During follow up, 67 cases of bacteriologically confirmed TB were detected giving an overall incidence rate of 0.45 per 100 person years (95% confidence interval 0.29-0.72. Black or mixed race, maternal education of primary school or less or unknown, a positive baseline QuantiFERON assay and a positive baseline TST were significant predictors of TB disease on adjusted analysis. CONCLUSION: The adolescent TB incidence found in a high burden setting will help TB vaccine developers plan clinical trials in this population. Latent TB infection and low socio-economic status were predictors of TB disease.

  8. GD SDR Automatic Gain Control Characterization Testing

    Science.gov (United States)

    Nappier, Jennifer M.; Briones, Janette C.

    2013-01-01

    The General Dynamics (GD) S-Band software defined radio (SDR) in the Space Communications and Navigation (SCAN) Testbed on the International Space Station (ISS) will provide experimenters an opportunity to develop and demonstrate experimental waveforms in space. The GD SDR platform and initial waveform were characterized on the ground before launch and the data will be compared to the data that will be collected during on-orbit operations. A desired function of the SDR is to estimate the received signal to noise ratio (SNR), which would enable experimenters to better determine on-orbit link conditions. The GD SDR does not have an SNR estimator, but it does have an analog and a digital automatic gain control (AGC). The AGCs can be used to estimate the SDR input power which can be converted into a SNR. Tests were conducted to characterize the AGC response to changes in SDR input power and temperature. This purpose of this paper is to describe the tests that were conducted, discuss the results showi ng how the AGCs relate to the SDR input power, and provide recommendations for AGC testing and characterization.

  9. Luminescence Properties of Self-Aggregating TbIII-DOTA-Functionalized Calix[4]arenes

    Directory of Open Access Journals (Sweden)

    Florian Mayer

    2018-01-01

    Full Text Available Self-aggregating calix[4]arenes carrying four DOTA ligands on the upper rim for stable complexation of paramagnetic GdIII-ions have already been proposed as MRI probes. In this work, we investigate the luminescence properties of TbIII-DOTA-calix[4]arene-4OPr containing four propyl-groups and compare them with those of the analog substituted with a phthalimide chromophore (TbIII-DOTA-calix[4]arene-3OPr-OPhth. We show that, given its four aromatic rings, the calix[4]arene core acts as an effective sensitizer of Tb-centered luminescence. Substituents on the lower rim can modulate the aggregation behavior, which in turn determines the luminescence properties of the compounds. In solid state, the quantum yield of the phthalimide derivative is almost three times as high as that of the propyl-functionalized analog demonstrating a beneficial role of the chromophore on Tb-luminescence. In solution, however, the effect of the phthalimide group vanishes, which we attribute to the large distance between the chromophore and the lanthanide, situated on the opposite rims of the calix[4]arene. Both quantum yields and luminescence lifetimes show clear concentration dependence in solution, related to the strong impact of aggregation on the luminescence behavior. We also evidence the variability in the values of the critical micelle concentration depending on the experimental technique. Such luminescent calix[4]arene platforms accommodating stable lanthanide complexes can be considered valuable building blocks for the design of dual MR/optical imaging probes.

  10. Luminescence Properties of Self-Aggregating TbIII-DOTA-Functionalized Calix[4]arenes

    Science.gov (United States)

    Mayer, Florian; Tiruvadi Krishnan, Sriram; Schühle, Daniel T.; Eliseeva, Svetlana V.; Petoud, Stéphane; Tóth, Éva; Djanashvili, Kristina

    2018-01-01

    Self-aggregating calix[4]arenes carrying four DOTA ligands on the upper rim for stable complexation of paramagnetic GdIII-ions have already been proposed as MRI probes. In this work, we investigate the luminescence properties of TbIII-DOTA-calix[4]arene-4OPr containing four propyl-groups and compare them with those of the analog substituted with a phthalimide chromophore (TbIII-DOTA-calix[4]arene-3OPr-OPhth). We show that, given its four aromatic rings, the calix[4]arene core acts as an effective sensitizer of Tb-centered luminescence. Substituents on the lower rim can modulate the aggregation behavior, which in turn determines the luminescence properties of the compounds. In solid state, the quantum yield of the phthalimide derivative is almost three times as high as that of the propyl-functionalized analog demonstrating a beneficial role of the chromophore on Tb-luminescence. In solution, however, the effect of the phthalimide group vanishes, which we attribute to the large distance between the chromophore and the lanthanide, situated on the opposite rims of the calix[4]arene. Both quantum yields and luminescence lifetimes show clear concentration dependence in solution, related to the strong impact of aggregation on the luminescence behavior. We also evidence the variability in the values of the critical micelle concentration depending on the experimental technique. Such luminescent calix[4]arene platforms accommodating stable lanthanide complexes can be considered valuable building blocks for the design of dual MR/optical imaging probes. PMID:29441345

  11. Double dimethylammonium sulphates of Tb, Dy, Ho, Er, Tm, Yb, Lu and Y

    International Nuclear Information System (INIS)

    Jordanovska, V.B.; Siftar, J.

    1986-01-01

    Double sulfates of rare earths with dimethylammonium were studied by means of thermogravimetry, derivative thermogravimetry and differential thermal analysis from 20 to 700 deg C. Quantitative gravimetric analysis was used for the determination of rare earths and sulfate. The mechanism of thermal decomposition is also suggested. (author)

  12. tb diagnostics challenges of tb diagnosis and treatment in south africa

    African Journals Online (AJOL)

    2007-06-01

    Jun 1, 2007 ... resultant 8 - 9 million cases of active tuberculosis (TB) and 1.6 million deaths annually.1 The tools used for diagnosis of TB have .... memory. We have shown that the 3-day INF- secretion from. PBMCs co-incubated with Mtb antigens is similar in both HIV- negative and HIV-positive controls, but the secretion ...

  13. Integration of TB and ART services fails to improve TB treatment ...

    African Journals Online (AJOL)

    The median CD4+ count of HIV-positive patients was 152 cells/μl (interquartile range (IQR) 71 - 277) for integrated facilities and 148 cells/μl (IQR 67 - 260) for single-service facilities. There was no statistical difference in the TB treatment outcome profile between integrated and single-service facilities for all TB patients (p=0.

  14. The performance and limitation of T-SPOT.TB for the diagnosis of TB in a high prevalence setting.

    Science.gov (United States)

    Zhu, Changtai; Liu, Zhonghua; Li, Zhiqiang; Mei, Shencong; Hu, Zhongyi

    2014-06-01

    Tuberculosis (TB) diagnosis remains difficulty. The previous reports have shown that the T-SPOT.TB assay may be a more promising diagnostic tool for TB, however, it needs a further study to evaluate the diagnostic value of T-SPOT.TB for the specific populations in a high prevalence setting. In this present study, we conducted stratified and comparable analyses to explore the clinical value and the limitation of T-SPOT.TB assay in TB diagnosis in a high TB prevalence setting, Southern China. A total of 413 subjects including 163 pulmonary TB (PTB), 39 extrapulmonary TB (EPTB), 106 non-TB pulmonary diseases (NTBPDs), 20 medical staff and 85 healthy controls were included in the study. According to T-SPOT.TB, there had a high incidence of latent TB infection (LTBI) in general population in Southern China, especially in the NTBPDS and medical staff. The T-SPOT.TB had a high performance in the diagnosis of active TB (ATB) in a lower risk of TB infection population such as the general population, however, the T-SPOT.TB for the diagnosis of ATB in the high risk of TB infection populations involving close contacts such as the patients with pulmonary diseases (PD) or medical staff isn't reliable due to the interference by LTBI. Under this condition, the value of rule-out of the assay was seemed to be better than that of rule-in. We believed that the T-SPOT.TB is suitable for screening both the EPTB and the ATB combined with diabetes mellitus (DM). However, we found that the sensitivity of T-SPOT.TB in sputum smear-negative population wasn't as high as that in smear-positive population. The T-SPOT.TB testing results should be interpreted with caution combined with subject's characteristics in a high prevalence setting.

  15. Synthesis and characterization of Gd-doped magnetite nanoparticles

    International Nuclear Information System (INIS)

    Zhang, Honghu; Malik, Vikash; Mallapragada, Surya; Akinc, Mufit

    2017-01-01

    Synthesis of magnetite nanoparticles has attracted increasing interest due to their importance in biomedical and technological applications. Tunable magnetic properties of magnetite nanoparticles to meet specific requirements will greatly expand the spectrum of applications. Tremendous efforts have been devoted to studying and controlling the size, shape and magnetic properties of magnetite nanoparticles. Here we investigate gadolinium (Gd) doping to influence the growth process as well as magnetic properties of magnetite nanocrystals via a simple co-precipitation method under mild conditions in aqueous media. Gd doping was found to affect the growth process leading to synthesis of controllable particle sizes under the conditions tested (0–10 at% Gd 3+ ). Typically, undoped and 5 at% Gd-doped magnetite nanoparticles were found to have crystal sizes of about 18 and 44 nm, respectively, supported by X-ray diffraction and transmission electron microscopy. Our results showed that Gd-doped nanoparticles retained the magnetite crystal structure, with Gd 3+ randomly incorporated in the crystal lattice, probably in the octahedral sites. The composition of 5 at% Gd-doped magnetite was Fe (3−x) Gd x O 4 (x=0.085±0.002), as determined by inductively coupled plasma mass spectrometry. 5 at% Gd-doped nanoparticles exhibited ferrimagnetic properties with small coercivity (~65 Oe) and slightly decreased magnetization at 260 K in contrast to the undoped, superparamagnetic magnetite nanoparticles. Templation by the bacterial biomineralization protein Mms6 did not appear to affect the growth of the Gd-doped magnetite particles synthesized by this method. - Highlights: • Gd-doped magnetite nanoparticles are synthesized via aqueous co-precipitation method under mild conditions. • Gd doping affects growth of magnetite nanoparticles leading to tunable particle size. • Gd-doped magnetite nanoparticles exhibit ferrimagnetic properties.

  16. Magnetocaloric properties and solid solution strengthening of Gd-C and Gd-Dy-C alloys

    International Nuclear Information System (INIS)

    Chen Yungui; Wu Jinping; Xiao Sufen; Zhang Tiebang; Tang Yongbai; Tu Mingjing

    2006-01-01

    In this paper, the near room temperature magnetic refrigerating solid solution alloys, Gd 1-x -C x (x ≤ 5 at.%) and Gd 0.98-x Dy x C 0.02 (x ≤ 20 at.%), were investigated together with a consideration of mechanical properties required by the container of the refrigerant material in a magnetic refrigerator. The results show that the micro-hardness of pure gadolinium metal can be much improved by adding carbon. The Curie temperature and adiabatic temperature changes of the Gd 1-x C x (x 0.98-x Dy x C 0.02 alloys can be tuned by adding dysprosium and their adiabatic temperature changes do not change much in a magnetic field change of 0-1 T

  17. Synthesis of Uniform Rare Earth Doped Gd2O2S Sub-micron Sized Spheres Using Gas-Aided Sulfurization and their Optical Characteristics.

    Science.gov (United States)

    He, Shuqing; Zhao, Xinyu; Tan, Mei Chee

    2017-01-01

    In this work, we report a detailed study of the synthesis of sub-micron sized Gd 2 O 2 S spheres using a two-step process: (1) amorphous precursor synthesis using the solvothermal method where a surfactant was used to control particle morphology, followed by (2) crystallization to form Gd 2 O 2 S polycrystalline spheres in a sulfur-rich environment. The crystallization and sulfurization processes are investigated by monitoring the crystal growth at different temperatures and under different environments using mainly x-ray diffraction and analysis of the precursor's thermal decomposition profile. The optical emissions of the Er and Yb-Er doped Gd 2 O 2 S upon excitation at 975 nm were investigated to identify the optimal dopant concentrations, optimal heat treatment temperature as well as to further elucidate any fine structure changes. Our results also show that the maximum emission intensities were obtained for a heat treatment temperature of 800 °C, where increased dopant diffusion coupled with non-uniform surface segregation at much higher temperatures led to non-uniform dopant distribution and reduced emission intensities. Our findings from these studies would be useful towards the synthesis of brightly-emitting Gd 2 O 2 S based luminescent materials as well as for the controlled gas-aided sulfurization of other metal oxysulfides.

  18. Evaluation of Gd and Gd159 as new approaches for cancer treatment

    International Nuclear Information System (INIS)

    Galvao, I.; Neves, M.J.

    2011-01-01

    Metal compounds have shown many biological activities and have been successfully used as anticancer agents such cisplatin. Actually gadolinium (Gd) complexed with a porphyrin Motexafin (MGd) has been investigated as redox-active compound for treatment of cancer. 1 59G d decays by beta emission with an energy of 970 keV and half-life of 18.59 hours. The de-excitation can be via gamma ray and internal conversion electron emission followed by auger electrons and x rays. Considering all of this 1 59G d could be a interesting radionuclide to be as a radio therapeutical agent. The aims of this works were to evaluate the cytotoxicity of Gd and 1 59G d on malignant brain tumors such as glioblastoma multiform, the most frequent brain tumors which has a very poor prognosis. For this purpose, it was used human glioblastoma cell lines T98 (mutant p53) and U87 (wild-type p53) to investigate the cytotoxicity of gadolinium on cell metabolism by MTT assay and also morphological changes, chromatin condensation by DAPI assay and ROS generation. Gadolinium was able to decrease cell viability, the cells presented morphological changes like round shapes and blebs formation after cell treatment with 5x10 -6 M of Gd. Nuclear changing and ROS generation occurred in a dose dependent way indicating the cytotoxic effect of Gd. Treatment with 1 59G d increased all of changes observed with treatment with Gd. These results state for an additive effect of metal toxicity and radioactivity inducing ROS generation as the main mechanism of anti tumoral action of 1 59G d. The results obtained indicated that the radioactive analogues of Gd have increased cytotoxic effects and gadolinium can be a metal of choice for development of new drugs for cancer treatment. (author)

  19. Min mentor er min voksenven

    DEFF Research Database (Denmark)

    Kaiser, Birte

    2009-01-01

    En artikel i bogen: 6 belysninger af vejledning, brydninger, forståelser & praksis. Artiklen er et sammendrag af en diskursanalyse fra 2008 fra projetrapporten: Ind under huden, www.vejledning.net...

  20. Forenklingens fire F'er

    DEFF Research Database (Denmark)

    Bentzen, Tina Øllgaard

    2017-01-01

    At fjerne styring er det, man ofte forbinder med afbureaukratisering, men det er ikke tilstrækkeligt, når man vil gå fra flotte ambitioner til en styring, som reelt opleves enklere. For at forenkle må man også forandre, forankre og fastholde styring, og det må ske i et samspil mellem de aktører...

  1. Er selvmord en synd? Nej

    DEFF Research Database (Denmark)

    Andersen, Svend

    2013-01-01

    Interview med den tese at selvmord ikke kan kaldes 'synd', dels fordi dette begreb er misvisende, dels fordi der findes forskellige former for selvmord: patologisk eller velovervejet. Det sidste må respekteres som udtryk for et myndigt menneskes selvbestemmelse.......Interview med den tese at selvmord ikke kan kaldes 'synd', dels fordi dette begreb er misvisende, dels fordi der findes forskellige former for selvmord: patologisk eller velovervejet. Det sidste må respekteres som udtryk for et myndigt menneskes selvbestemmelse....

  2. Ab initio study of the structural, electronic, elastic and magnetic properties of Cu2GdIn, Ag2GdIn and Au2GdIn

    International Nuclear Information System (INIS)

    Berri, Saadi; Maouche, Djamel; Zerarga, Fares; Medkour, Youcef

    2012-01-01

    We preformed first-principle calculations for the structural, electronic, elastic and magnetic properties of Cu 2 GdIn, Ag 2 GdIn and Au 2 GdIn using the full-potential linearized augmented plane wave (FP-LAPW) scheme within the generalized gradient approximation by Wu and Cohen (GGA-WC), GGA+U, the local spin density approximation (LSDA) and LSDA+U. The lattice parameters, the bulk modulus and its pressure derivative and the elastic constants were determined. Also, we present the band structures and the densities of states. The electronic structures of the ferromagnetic configuration for Heusler compounds (X 2 GdIn) have a metallic character. The magnetic moments were mostly contributed by the rare-earth Gd 4f ion.

  3. Electronic and Ionic Transport in Ce0.8PrxTb0.2−xO2−δ and Evaluation of Performance as Oxygen Permeation Membranes

    DEFF Research Database (Denmark)

    Chatzichristodoulou, Christodoulos; Hendriksen, Peter Vang

    2012-01-01

    to that of Ce0.9Gd0.1O1.95−δ, and was found to increase with increasing Pr/Tb ratio. The oxide ion mobility in Ce0.8PrxTb0.2−xO2−δ is similar to that in Ce1−2δGd2δO2−δ at the same oxygen vacancy concentration. Based on the measured ionic and electronic conductivities, fluxes through thin film Ce0.8PrxTb0.2−xO2......The electronic conductivity of Ce0.8PrxTb0.2−xO2−δ (x = 0, 0.05, 0.10, 0.15, 0.20) was determined in the oxygen activity range aO2 ≈ 103 – 10−17 at 700–900°C by Hebb-Wagner polarization. The electronic conductivity of all the Ce0.8PrxTb0.2−xO2−δ compositions was significantly enhanced as compared......−δ membranes were calculated. Calculated fluxes exceed 10 Nml min−1 cm−2 under oxyfuel relevant conditions (T = 800°C, aO2,permeate side = 10−3). Hence, in terms of transport properties, these materials are promising for this application. Interference between the ionic and electronic flows has...

  4. Particle-phonon excitations in valence-neutron and valence-proton nuclei around 146Gd

    International Nuclear Information System (INIS)

    Collatz, R.D.

    1994-07-01

    The present thesis deals with the one-valence-particle nuclei 147 Tb and 151 Er. The main purpose of the study was, to study characteristic properties of the particle-phonon excitations of these nuclei. In the one-valence-proton nucleus 147 Tb from the πh 11/2 x3 - septet only the 15/2 + and 17/2 + Yrast states were known, which underly a strong diagonal exchange interaction. At mass separators in β decay experiments of the 1/2 + and the 11/2 -147 Dy activities and in in-beam experiments layed out on excitation of states above the Yrast line with 6 Li beams the nucleus 147 Tb was spectroscoped. The combination of these three data sets made the nearly complete covering of the spin range from 1/2 to 27/2 of the low-lying states in 147 Tb possible. At the whole in this nucleus more than 100 hitherto unknown states could be placed and farly characterized. The unusually manifold data allowed to identify beside the complete πh 11/2 x3 - septet also very much further particlexphonon states. Furthermore in the excitation range between 2.5 and 4 MeV numerous three-quasiparticle excitations were observed and in very sufficient way described by parameter-free shell-model calculations. A further important result is the manifestation of a neutron-one-particle-one-hole state with I=27/2, which lies with 3.7 MeV excitation close to the Yrast line. (orig./HSI)

  5. The role of antiretroviral therapy in reducing TB incidence and mortality in high HIV-TB burden countries

    Directory of Open Access Journals (Sweden)

    Anthony D Harries

    2016-03-01

    Full Text Available With the adoption of the new Sustainable Development Goals in 2016, all countries have committed to end the tuberculosis (TB epidemic by 2030, defined as dramatic reductions in TB incidence and mortality combined with zero TB-induced catastrophic costs for families. This paper explores how antiretroviral therapy (ART in high HIV-TB burden countries may help in reducing TB incidence and mortality and thus contribute to the ambitious goal of ending TB. ART in people living with HIV has a potent TB preventive effect, with this being most apparent in those with the most advanced immunodeficiency. Early ART also significantly reduces the risk of TB, and with new World Health Organization guidance released in 2015 about initiating ART in all persons living with HIV irrespective of CD4 count, there is the potential for enormous benefit at the population level. Already, several countries with high HIVTB burdens have seen dramatic declines in TB case notification rates since ART scale up started in 2004. In patients already diagnosed with HIV-associated TB, mortality can be significantly decreased by ART, especially if started within 2–8 weeks of anti-TB treatment. The benefits of ART on TB incidence and TB mortality can be further augmented respectively by the addition of isoniazid preventive therapy and cotrimoxazole preventive therapy. These interventions must be effectively implemented and scaled up in order to end the TB epidemic by 2030.

  6. Combination of Cytokine Responses Indicative of Latent TB and Active TB in Malawian Adults

    Science.gov (United States)

    Hur, Yun-Gyoung; Gorak-Stolinska, Patricia; Ben-Smith, Anne; Lalor, Maeve K.; Chaguluka, Steven; Dacombe, Russell; Doherty, T. Mark; Ottenhoff, Tom H.; Dockrell, Hazel M.; Crampin, Amelia C.

    2013-01-01

    Background An IFN-γ response to M. tuberculosis-specific antigens is an effective biomarker for M. tuberculosis infection but it cannot discriminate between latent TB infection and active TB disease. Combining a number of cytokine/chemokine responses to M. tuberculosis antigens may enable differentiation of latent TB from active disease. Methods Asymptomatic recently-exposed individuals (spouses of TB patients) were recruited and tuberculin skin tested, bled and followed-up for two years. Culture supernatants, from a six-day culture of diluted whole blood samples stimulated with M. tuberculosis-derived PPD or ESAT-6, were measured for IFN-γ, IL-10, IL-13, IL-17, TNF-α and CXCL10 using cytokine ELISAs. In addition, 15 patients with sputum smear-positive pulmonary TB were recruited and tested. Results Spouses with positive IFN-γ responses to M. tuberculosis ESAT-6 (>62.5 pg/mL) and TB patients showed high production of IL-17, CXCL10 and TNF-α. Higher production of IL-10 and IL-17 in response to ESAT-6 was observed in the spouses compared with TB patients while the ratios of IFN-γ/IL-10 and IFN-γ/IL-17 in response to M. tuberculosis-derived PPD were significantly higher in TB patients compared with the spouses. Tuberculin skin test results did not correlate with cytokine responses. Conclusions CXCL10 and TNF-α may be used as adjunct markers alongside an IFN-γ release assay to diagnose M. tuberculosis infection, and IL-17 and IL-10 production may differentiate individuals with LTBI from active TB. PMID:24260295

  7. Combination of cytokine responses indicative of latent TB and active TB in Malawian adults.

    Directory of Open Access Journals (Sweden)

    Yun-Gyoung Hur

    Full Text Available An IFN-γ response to M. tuberculosis-specific antigens is an effective biomarker for M. tuberculosis infection but it cannot discriminate between latent TB infection and active TB disease. Combining a number of cytokine/chemokine responses to M. tuberculosis antigens may enable differentiation of latent TB from active disease.Asymptomatic recently-exposed individuals (spouses of TB patients were recruited and tuberculin skin tested, bled and followed-up for two years. Culture supernatants, from a six-day culture of diluted whole blood samples stimulated with M. tuberculosis-derived PPD or ESAT-6, were measured for IFN-γ, IL-10, IL-13, IL-17, TNF-α and CXCL10 using cytokine ELISAs. In addition, 15 patients with sputum smear-positive pulmonary TB were recruited and tested.Spouses with positive IFN-γ responses to M. tuberculosis ESAT-6 (>62.5 pg/mL and TB patients showed high production of IL-17, CXCL10 and TNF-α. Higher production of IL-10 and IL-17 in response to ESAT-6 was observed in the spouses compared with TB patients while the ratios of IFN-γ/IL-10 and IFN-γ/IL-17 in response to M. tuberculosis-derived PPD were significantly higher in TB patients compared with the spouses. Tuberculin skin test results did not correlate with cytokine responses.CXCL10 and TNF-α may be used as adjunct markers alongside an IFN-γ release assay to diagnose M. tuberculosis infection, and IL-17 and IL-10 production may differentiate individuals with LTBI from active TB.

  8. Gd3Fe5O12 near the compensation temperature

    DEFF Research Database (Denmark)

    Hansen, Britt Rosendahl; Kuhn, Luise Theil; Bahl, Christian Robert Haffenden

    2010-01-01

    Applying a magnetic eld to a magnetic material will usually cause a change in the magnetic entropy of the material. If done adiabatically, the temperature of the material will change - this is the magnetocaloric eect. Gadolinium Iron Garnet (GdIG, Gd3Fe5O12) is a complex magnetic system with three...... magnetic sublattices, one Gd and two Fe. The Fe sites are strongly coupled antiferromagnetically, i.e. the magnetic moments are anti-parallel, while the Gd magnetic moment is weakly coupled antiferromagnetically to the resulting Fe moment. This results in a compensation temperature, where the total...

  9. Anomalous Hall effect in Fe/Gd bilayers

    KAUST Repository

    Xu, W. J.

    2010-04-01

    Non-monotonic dependence of anomalous Hall resistivity on temperature and magnetization, including a sign change, was observed in Fe/Gd bilayers. To understand the intriguing observations, we fabricated the Fe/Gd bilayers and single layers of Fe and Gd simultaneously. The temperature and field dependences of longitudinal resistivity, Hall resistivity and magnetization in these films have also been carefully measured. The analysis of these data reveals that these intriguing features are due to the opposite signs of Hall resistivity/or spin polarization and different Curie temperatures of Fe and Gd single-layer films. Copyright (C) EPLA, 2010

  10. Irradiation response of radio-frequency sputtered Al/Gd2O3/p-Si MOS capacitors

    Science.gov (United States)

    Kahraman, A.; Yilmaz, E.

    2017-10-01

    The usage of the Gadolinium oxide (Gd2O3) as sensitive region in the MOS (Metal-Oxide-Semiconductor)-based dosimeters was investigated in the presented study. The Gd2O3 films grown on p-type Si (100) by RF magnetron sputtering were annealed at 800 °C under N2 ambient. The back and front metal contacts were establishes to produce MOS capacitors. The fabricated Gd2O3 MOS capacitors were irradiated in the dose range 0.5-50 Gy by 60Co gamma source. The performed Capacitance-Voltage (C-V) curves of the Gd2O3 MOS capacitors shifted to right side relative to pre-irradiation one. While continuous increments in the oxide trapped charges with increasing in gamma dose were observed, interface trapped charges fluctuated in the studied dose range. However, the variation of the interface trapped charge densities was found in the order of 1011 cm-2 and no significant variation was observed with applied dose. These results confirm that a significant deterioration does not occur in the capacitance during the irradiation. The higher oxide trapped charges compared to interface trapped charges showed that these traps were more responsible for the shift of the C-V curves. The sensitivity and percentage fading after 105 min of the Gd2O3 MOS capacitor were found as 39.7±1.4 mV/Gy and 14.5%, respectively. The devices sensitivity was found to be higher than that of capacitors composed of Er2O3, Sm2O3, La2O3, Al2O3, and SiO2, but, the high fading values is seen as a major problem for these capacitors. Finally, the barrier height was investigated with gamma exposure and the results showed that its value increased with increasing in radiation dose due to possible presence of the acceptor-like interface states.

  11. Screening af kulturmiljøer

    DEFF Research Database (Denmark)

    2017-01-01

    Arkitektskolen Aarhus sætter fokus på kulturmiljøer i Danmarks yderområder. Screening af Kulturmiljøer (SAK) er et redskab til at vurdere kulturmiljøer ud fra aflæselige parametre, så kulturarvens værdier, egenskaber og udviklingspotentialer bliver synlige. Formålet er at skabe nye muligheder og...

  12. High Field Magnetization of Tb Single Crystals

    DEFF Research Database (Denmark)

    Roeland, L. W.; Cock, G. J.; Lindgård, Per-Anker

    1975-01-01

    The magnetization of Tb single crystals was measured in magnetic fields to 34T along the hard direction at temperature of 1.8, 4.2, 65.5 and 77K, and along with easy direction at 4.2 and 77K. The data are compared with the results of a self-consistent spin wave calculation using a phenomenological...

  13. Tuberculosis: Learn the Signs and Symptoms of TB Disease

    Science.gov (United States)

    ... this? Submit What's this? Submit Button Past Emails Tuberculosis (TB) Disease: Symptoms and Risk Factors Language: English ( ... Español (Spanish) Recommend on Facebook Tweet Share Compartir Tuberculosis (TB) is a disease caused by bacteria that ...

  14. Combination of TB lymphadenitis and metastatic LAP in breast cancer

    Directory of Open Access Journals (Sweden)

    Abdolhassan Talaiezadeh

    2015-06-01

    Full Text Available Tuberculosis (TB may present as pulmonary and extra-pulmonary. TB lymphadenitis is the most common presentation of extra-pulmonary TB. TB lymphadenitis should be taken into account in the differential diagnosis of different disorders such as metastatic lymphadenopathy. The reported patient was a 65-year-old lady with breast cancer and conglomerated and matted axillary lymphadenopathy who received chemotherapy. She presented with more extensive axillary LAP contrary to our expectation. Modified radical mastectomy was done and pathology analysis reported TB lymphadenitis associated with metastatic LAP. Under cover of anti-TB therapy adjuvant chemoradiation therapy was started. Accordingly, we recommend TB be ruled out in every patient who needs chemotherapy in the endemic region because chemotherapy may cause the extension of TB in the body.

  15. Synthesis and Characterization of Hollow Magnetic Alloy (GdNi2, Co5Gd Nanospheres Coated with Gd2O3

    Directory of Open Access Journals (Sweden)

    Wang Li

    2014-01-01

    Full Text Available Uniform magnetic hollow nanospheres (GdNi2, Co5Gd coated with Gd2O3 have been successfully prepared on a large scale via a urea-based homogeneous precipitation method using silica (SiO2 spheres as sacrificed templates, followed by subsequent heat treatment. Nitrogen sorption measurements and scanning electron microscope reveal that these hollow-structured magnetic nanospheres have the mesoporous shells that are composed of a large amount of uniform nanoparticles. After reduction treatment, these nanoparticles exhibit superparamagnetism that might have potential applications in medicine. Furthermore, the developed synthesis route may provide an important guidance for the preparation of other multifunctional hollow spherical materials.

  16. Chest Radiographs for Pediatric TB Diagnosis: Interrater Agreement and Utility

    NARCIS (Netherlands)

    Kaguthi, G.; Nduba, V.; Nyokabi, J.; Onchiri, F.; Gie, R.; Borgdorff, M.

    2014-01-01

    The chest radiograph (CXR) is considered a key diagnostic tool for pediatric tuberculosis (TB) in clinical management and endpoint determination in TB vaccine trials. We set out to compare interrater agreement for TB diagnosis in western Kenya. A pediatric pulmonologist and radiologist (experts), a

  17. Assessment of the Diagnostic Potential of Clinotech TB Screen Test ...

    African Journals Online (AJOL)

    The Clinotech TB Screen test, a 3rd generation multi-antigen rapid chromatographic immunoassay for detection of IgG antibodies in serum against recombinant protein antigens 38kDa, 16kDa and 6kDa, was assessed for its diagnostic potential for diagnosis of active pulmonary TB in routine TB control programme in Abia ...

  18. Antiretroviral treatment uptake in patients with HIV- associated TB ...

    African Journals Online (AJOL)

    ART results in a 64 - 95% reduction in mortality risk 5 and is an essential component of care. How soon to start. ART after TB treatment initiation has become clearer from randomised controlled trials. These show that integration of ART and TB treatment in all HIV-associated TB patients regardless of CD4 count significantly.

  19. Antiretroviral treatment uptake in patients with HIV associated TB ...

    African Journals Online (AJOL)

    Background. Delivery of integrated care for patients with HIV-associated TB is challenging. We assessed the uptake and timing of antiretroviral treatment (ART) among eligible patients attending a primary care service with co-located ART and TB clinics. Methods. In a retrospective cohort study, all HIV-associated TB patients ...

  20. Comparison of PPD test in household contacts of smear-positive and -negative tuberculosis (TB

    Directory of Open Access Journals (Sweden)

    Zohreh Azarkar

    2015-01-01

    Conclusions: The most important way to prevent TB is omission of the disease transmission sources (TB patients by anti-TB treatment. Extensive studies are needed to ensure that contacts of patients with pulmonary TB are identified and appropriately screened.

  1. Prism inside. Spectroscopic and magnetic properties of the lanthanide(III) chloride oxidotungstates(VI) Ln{sub 3}Cl{sub 3}[WO{sub 6}] (Ln = La - Nd, Sm - Tb)

    Energy Technology Data Exchange (ETDEWEB)

    Dorn, Katharina V.; Blaschkowski, Bjoern; Hartenbach, Ingo [Institute for Inorganic Chemistry, University of Stuttgart (Germany); Foerg, Katharina; Netzsch, Philip; Hoeppe, Henning A. [Institute for Physics, University of Augsburg (Germany)

    2017-11-17

    The lanthanide(III) chloride oxidotungstates(VI) with the formula Ln{sub 3}Cl{sub 3}[WO{sub 6}] for Ln = La - Nd, Sm - Tb were synthesized by solid-state reactions utilizing the respective lanthanide trichloride, lanthanide sesquioxide (where available), and tungsten trioxide together with lithium chloride as flux. The title compounds crystallize hexagonally in space group P6{sub 3}/m (no. 176, a = 941-909, c = 543-525 pm, Z = 2). The structures comprise crystallographically unique Ln{sup 3+} cations surrounded by six O{sup 2-} and four Cl{sup -} anions (C.N. = 10) forming distorted tetracapped trigonal prisms as well as rather uncommon trigonal prismatic [WO{sub 6}]{sup 6-} units, whose edges are coordinated by nine Ln{sup 3+} cations. Thus, a {sup 3}{sub ∞}{([WO_6]Ln"e_9_/_3)"3"+} framework (e = edge-sharing) is created, which contains tube-shaped channels along [001] lined with chloride anions. To elucidate the spectroscopic and magnetic properties of the obtained pure phase samples, single-crystal Raman (for Ln = La - Nd, Sm-Tb), diffuse reflectance (for Ln = La, Pr, Nd, Gd), and luminescence spectroscopy (for bulk Ln{sub 3}Cl{sub 3}[WO{sub 6}] (Ln = La, Eu, Gd, Tb) and Eu{sup 3+}- or Tb{sup 3+}-doped derivatives of La{sub 3}Cl{sub 3}[WO{sub 6}] and Gd{sub 3}Cl{sub 3}[WO{sub 6}], respectively) were performed and their temperature-dependent magnetic moments (for Ln = Pr, Nd, Gd) were determined. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Co-operative energy transfer in Yb3+-Er3+ co-doped SrGdxOy upconverting phosphor

    Science.gov (United States)

    Kumar, Ashwini; Pathak, Trilok K.; Dhoble, S. J.; . Terblans, J. J.; Swart, H. C.

    2018-04-01

    Upconversion nanoparticles (UCNPs) have shown considerable interest in many fields; however, low upconversion efficiency of UCNPs is still the most severe limitation of their applications. Yb3+ and Er3+ co-doped SrGd4O7/Gd2O3(SGO) upconversion (UC) phosphors were synthesized by a modified co-precipitation process. The UC properties were investigated by direct excitation with a 980 nm laser. It was observed that the as prepared materials showed relatively strong green emission, while upon the incorporation of the Er3+ ion, there was an increase in the upconversion luminescence intensity for the red component. The effect of different doping concentration of Er3+on the emission spectra and X-ray diffraction patterns of the UC materials have also been studied. The luminescence lifetimes and Commission Internationale de L'Eclairage coordinates for these as prepared samples were determined to understand the energy transfer (ET) mechanisms occurring between Yb3+ and Er3+ in the SGO host matrix. The UC luminescence intensity as a function of laser pump power was monitored and it was confirmed that the UC process in SGO:Yb3+/Er3+is a two-photon absorption process. The findings reported here are expected to provide a better approach for understanding of the ET mechanisms in the oxide based Yb3+/Er3+ co-doped UC phosphors. This study might be helpful in precisely defined applications where optical transitions are essential criterion and this can be easily achieved by smart tuning of the emission properties of Yb3+/Er3+ co-doped UC phosphors.

  3. TB diagnostic process management of patients in a referral hospital in Mozambique in comparison with the 2007 WHO recommendations for the diagnosis of smear-negative pulmonary TB and extrapulmonary TB

    NARCIS (Netherlands)

    Bos, Jeannet C.; Smalbraak, Lisette; Macome, Augusto C.; Gomes, Ermelinda; van Leth, Frank; Prins, Jan M.

    2013-01-01

    In sub-Saharan African countries, the high proportion of smear-negative pulmonary TB (SNTB) and extrapulmonary TB (EPTB) contributes to a delay in TB diagnosis and treatment. We evaluated the TB diagnostic process of adult patients with presumptive TB in a referral hospital in Mozambique according

  4. Enhanced room temperature multiferroicity in Gd doped BFO

    CSIR Research Space (South Africa)

    Pradhan, SK

    2009-01-01

    Full Text Available deficient Gd doped multiferroic BFO system. At particular doping level of Gd, this bulk ceramics showed spectacular M~H behavior at room temperature which is likely to open a new avenue for the potential applications in information storing technology as well...

  5. The magnetic anisotropy of Gd-Y alloys

    Science.gov (United States)

    Phu Thuy, Nguyen; Verdonk, H. J.; Menovsky, A.; Franse, J. J. M.; Gersdorf, R.

    1983-02-01

    Magnetic torque curves on single crystals of Gd 1- xY x ( x ⩽ 0.1) show a reduction of the anomalous contribution that was observed in pure Gd, with increasing Y-content. Several explanations of this phenomenon are indicated in this paper.

  6. Propiedades estructurales y magnéticas de aleaciones Gd0.257 -xTbxFe0.743 obtenidas por aleamiento mecánico

    Directory of Open Access Journals (Sweden)

    Mauricio Galvis-Patiño

    2017-01-01

    Full Text Available En el presente trabajo se reporta el estudio de las propiedades estructurales y magnéticas de la composición en forma de polvo de Gd0.257-xTbxFe0.743 con x=0,  0.1285,  0.257,preparados por Aleamiento Mecánico (AM en atmosfera de argón durante 72 horas mediante un molino planetario de alta energía ;la caracterización estructural se realizó por medio de Difractometría de rayos X(DRX, para la caracterización magnética se utilizó la espectroscopía Mössbauer, los ciclos de histéresis se llevaron a cabo a través de  PPMS (Physical Property Measurement System, Sistema de Medidas de Propiedades Físicas. La fase de α-Fe se presenta en los tres difractogramas mediante un pico característico cuya  intensidad disminuye al reemplazar el Tb por el Gd, presentándose la menor en x= 0 así mismo se observa un aumento de su ancho atribuible a la presencia de átomos de Gd en lugares propios del Fe. Los espectros Mössbauer (EM fueron ajustados con sextetos, dobletes, singletes y distribuciones de campo hiperfino lo que señala que el orden magnético se ve alterado al sustituir el Tb por el Gd en la composición. Las propiedades magnéticas extrínsecas de la composición en estudio, la caracterizan como materiales magnéticamente semiduros.

  7. Inverse effect of morphotropic phase boundary on the magnetostriction of ferromagnetic Tb1-xGdxCo2

    Science.gov (United States)

    Zhou, Chao; Ren, Shuai; Bao, Huixin; Yang, Sen; Yao, Yonggang; Ji, Yuanchao; Ren, Xiaobing; Matsushita, Yoshitaka; Katsuya, Yoshio; Tanaka, Masahiko; Kobayashi, Keisuke

    2014-03-01

    The morphotropic phase boundary (MPB) has been utilized extensively in ferroelectrics and recently has attracted interest in ferromagnets [S. Yang, H. Bao, C. Zhou, Y. Wang, X. Ren, Y. Matsushita, Y. Katsuya, M. Tanaka, K. Kobayashi, X. Song, and J. Gao, Phys. Rev. Lett. 104, 197201 (2010), 10.1103/PhysRevLett.104.197201; R. Bergstrom, M. Wuttig, J. Cullen, P. Zavalij, R. Briber, C. Dennis, V. O. Garlea, and M. Laver, Phys. Rev. Lett. 111, 017203 (2013), 10.1103/PhysRevLett.111.017203] for obtaining enhanced large field-induced strain. Here we report that the MPB can also lead to weakening (the inverse effect as compared to the known MPB materials) of field-induced strain, as exhibited in the Tb1-xGdxCo2 system. With synchrotron x-ray diffractometry, the structure symmetry of TbCo2-rich compositions is detected to be rhombohedral below TC and that of GdCo2-rich compositions is tetragonal. The MPB composition Tb0.1Gd0.9Co2, corresponding to the two phases (rhombohedral and tetragonal) of coexistence, shows the exotic minimum (near zero) magnetostriction as well as the largest magnetic susceptibility among all samples. Further analysis suggests that whether MPB can enhance or weaken magnetostriction is determined by the degree of magnetic ordering of two end members that form ferromagnetic MPBs, which was not considered previously. Our work not only reveals a new type of ferromagnetic MPB, but also provides a new recipe for designing functional high-susceptibility and low-strain magnetic materials.

  8. Gd-DTPA-enhanced dynamic MR imaging of the kidney

    International Nuclear Information System (INIS)

    Choyke, P.L.; Frank, J.A.; Carvlin, M.J.; Austin, H.; Girton, M.J.; Inscoe, S.; Black, J.

    1988-01-01

    Dynamic Gd-DTPA-enhanced MR imaging potentially can provide both anatomic and physiologic information about the kidneys. The authors performed 42 animal imaging studies with 1.5-T MR imaging after a bolus of Gd-DTPA (0.1 mmol/kg) was given. A reproducible pattern of enhancement was observed that could be divided into three phases. In phase I a cortical blush was seen, representing intravascular contrast. Phase II represented the tubular concentration of Gd-DTPA and was depicted as a centrally migrating band that reversed direction in the inner medulla. Phase III was a gradual darkening of the inner medulla caused by concentration in the collecting ducts. This pattern was predictably altered by hydration status. The patterns observed reflected alterations in concentration of Gd-DTPA occurring in the renal tubules and collecting ducts. Gd-DTPA-enhanced renal MR imaging is promising as a renal imaging technique

  9. Ferrimagnetic properties of Co/(Gd-Co) multilayers

    International Nuclear Information System (INIS)

    Svalov, A.V.; Fernandez, A.; Vas'kovskiy, V.O.; Tejedor, M.; Barandiaran, J.M.; Orue, I.; Kurlyandskaya, G.V.

    2006-01-01

    Co/(Gd-Co) multilayers have been prepared by rf-sputtering and investigated by means of Transverse Magnetooptic Kerr Effect (TMOKE), SQUID and VSM magnetometry. The composition of amorphous Gd 0.36 Co 0.64 layers was chosen so that their saturation magnetization was dominated by Gd moments in all the temperature range. Co and Gd-Co layers formed a macroscopic ferrimagnetically coupled system displaying a compensation temperature. Complete magnetic moment compensation was found at such point. An inversion of TMOKE hysteresis loops and a divergent behaviour of coercivity were also observed. By changing the layers thickness it has been possible to control the magnetic characteristics of the Co/(Gd-Co) structures, in particular the compensation takes place at different temperatures

  10. Fabrication of (U,Gd)O{sub 2} pellets and development of method for Gd content measurement

    Energy Technology Data Exchange (ETDEWEB)

    Kim, K. S.; Song, K. W.; Kang, K. W.; Yang, J. H.; Kim, J. H.; Lee, C. B. [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2002-05-01

    The goals of the investigation reported herein are to develope the recycling process of defective (U,Gd)O{sub 2} pellets and quality analysis method of sintered (U,Gd)O{sub 2} pellet. (U,Gd){sub 3}O{sub 8} powder is produced by oxidizing defective pellet then mixed with UO{sub 2} and Gd{sub 2}O{sub 3} powder. The mixed powder is milled, pressed and sintered to fabricate (U,Gd)O{sub 2} pellet. In above recycling process, (U,Gd){sub 3}O{sub 8} powder properties and milling condition are greatly affect the final sintered pellet quality of (U,Gd)O{sub 2}. The effects of oxidation temperature and time on powder property of recycled (U,Gd){sub 3}O{sub 8}, and milling method and time of powder mixture on sintered pellet property were investigated. The mixture had Gd{sub 2}O{sub 3} contents of 6 and 10wt% and also had recycled (U,Gd){sub 3}O{sub 8} contents of between 0 to 20wt%, respectively. The properties of sintered pellet such as density, grain size, fraction of cluster, Gd homogeneity are analysed and compared with those of pellets produced by foreign companies. The result shows that our pellet quality is compatible with or better than imported pellets. The more simple and effective way to measure the Gd contents in (U,Gd)O{sub 2} sintered pellet was invented. In first, we oxidized a certain amount of (U{sub 1-x}Gd{sub x})O{sub 2+z} pellet to (U{sub 1-x}Gd{sub x}){sub 3}O{sub 8} powder by annealing between 400{approx}950 .deg. C in air and measured the weight of it(W{sub 1}). And then annealing temperature raised to higher than 950 .deg. C and measured the weight of specimen(W{sub 2}). We found that (U{sub 1-x}Gd{sub x}){sub 3}O{sub 8} phase separated into (U{sub 1-y}Gd{sub y}){sub 4}O{sub 9} and U{sub 3}O{sub 8} in this annealing stage. In addition, the Gd atomic fraction in (U{sub 1-y}Gd{sub y}){sub 4}O{sub 9}, that is y, is independent of initial Gd contents x and has a fixed value. Using above described relations, we can finally found that {chi} in (U{sub 1-x}Gd

  11. Ro på: Solen er stille

    DEFF Research Database (Denmark)

    Pedersen, Jens Olaf Pepke

    2008-01-01

    Efter at Solen har øget sin aktivitet gennem 100 år, er der nu tydelige tegn på, at den er ved at falde til ro. Er den ved at gå i dvale? Og vil det i så fald udløse en global kuldeperiode?......Efter at Solen har øget sin aktivitet gennem 100 år, er der nu tydelige tegn på, at den er ved at falde til ro. Er den ved at gå i dvale? Og vil det i så fald udløse en global kuldeperiode?...

  12. Den sproglige leg er super fly

    DEFF Research Database (Denmark)

    Just, Sine Nørholm

    2013-01-01

    Man kan rappe om alt. I hvert fald hvis man er Marvelous Mosell. I spændingsfeltet mellem fiktion og virkelighed skaber Mosell sin persona i et forjættende 80' er-univers der på en og samme tid er vildt overdrevet og helt autentisk.......Man kan rappe om alt. I hvert fald hvis man er Marvelous Mosell. I spændingsfeltet mellem fiktion og virkelighed skaber Mosell sin persona i et forjættende 80' er-univers der på en og samme tid er vildt overdrevet og helt autentisk....

  13. N-ov-emb-er

    Indian Academy of Sciences (India)

    " to. Andrew Z Fire - Stanford University School of Medicine Stanford, CA, USA. Craig C Mello - University of Massachusetts Medical School Worcester, MA, USA. -96----------------------------~~--------R-ES-O-N-A-N-C-E--1 -N-ov-e-m-b-er--2-oo-6.

  14. Benefits of Gd for High Energy Neutrinos in SuperK-Gd

    Science.gov (United States)

    Fernández, Pablo; Super-Kamiokande Collaboration

    2017-09-01

    The SuperK-Gd project is the approved upgrade of the Super-Kamiokande (SK) detector in order to enable it to efficiently (> 80%) detect thermal neutrons by dissolving 0.2% of gadolinium sulphate (Gd2(SO4)3) into its water. This ability has also significant advantages in the analysis of high energy (> 102 MeV) neutrinos in SK, namely atmospheric and long baseline neutrinos from T2K. Here we present the improvements due to the use of the tagged final state neutrons in the separation of the interacting neutrinos and antineutrinos, the distinction between Neutral Current and Charged Current neutrino interactions, and the neutrino energy reconstruction. We study the impact of those features on both, atmospheric and long baseline neutrino oscillation analyses.

  15. Yellow phosphors doping with Gd 3, Tb 3 and Lu 3 in MTiO3 (M= Mg ...

    Indian Academy of Sciences (India)

    Esra Korkmaz1 Nilgun Ozpozan Kalaycioglu2 V Emir Kafadar3. Faculty of Science and Arts, Department of Chemistry, Bozok University, Yozgat 66900, Turkey; Faculty of Science, Department of Chemistry, Erciyes University, Kayseri 38039, Turkey; Department of Engineering Physics, Gaziantep University, Gaziantep ...

  16. Search for superdeformation in 144Gd

    International Nuclear Information System (INIS)

    Vivien, J.P.; Nourreddine, A.; Beck, F.A.; Byrski, T.; Gehringer, C.; Haas, B.; Merdinger, J.C.; Dudek, J.; Nazarewicz, W.

    1986-01-01

    Quasi-continuum γ-decay studies of 144 Gd have been performed using the 120 Sn( 28 Si,4n)reaction at 125, 135, 145 and 155 MeV bombarding energies. Angular distribution and multiplicity measurements have been done at the above energies. At 145 MeV bombarding energy a lifetime measurement has also been performed. Although a collective behaviour has been observed, the present data do not give evidence for population of superdeformed rotational bands. Theoretical interpretation using the cranking model with the Woods-Saxon field is given. The effects of temperature and pairing on the superdeformed configuration are discussed; superdeformation effects are predicted to disappear below I ∼ 60-70 ℎ when temperature exceeds ∼ 500 KeV

  17. New perspective for GdNCT. Gd-DTPA reaches the nucleus of glioblastoma cells in culture and in vivo

    International Nuclear Information System (INIS)

    Stasio, G. de; Gilbert, B.; Frazer, B.H.

    2000-01-01

    We investigated the prospects of gadolinium as a neutron capture therapy agent by combining three independent techniques to study the uptake of Gd-DTPA in vitro, in cultured glioblastoma cells, and in vivo, in the glioblastoma tissue sections after injection of Gd-DTPA and tumor extraction. We show that gadolinium not only penetrates the plasma membrane of glioblastoma cells grown in culture, but we also observe a statistically significant higher concentration of Gd in the nucleus relative to the cytoplasm. For the in vivo experiments, Gd-DTPA was administered to 6 glioblastoma patients before neurosurgery. The extracted bioptic tissue was then analyzed with spectromictroscopy, showing Gd localized in the nuclei of glioblastoma cells in 5 patients out of the 6 analyzed. (author)

  18. Synthesis, characterization and thermal behavior: Gd(NO3)3.6H2O to Gd2O3

    International Nuclear Information System (INIS)

    Ghonge, Darshana K.; Sheelvantra, Smita S.; Kalekar, Bhupesh B.; Raje, Naina

    2015-01-01

    Gadolinium oxide finds its application in nuclear as well as medical industry. It has been prepared from the thermal decomposition of gadolinium nitrate hexahydrate. Surface area of the synthesized compound was measured as 19 m 2 /g. EDS data shows only the presence of gadolinium and oxygen in the synthesized compound with the Gd to O ratio as calculated for Gd 2 O 3 , suggests the formation of pure Gd 2 O 3 . XRD analysis confirms the formation of pure cubic phase Gd 2 O 3 . In the absence of any report on the thermal behavior of GdNH, present studies have been carried out to understand the decomposition mechanism using simultaneous TG - DTA - EGA measurements

  19. Test of E1-radiative strength function and level density models by 155 Gd (n,2γ) 156 Gd reaction

    International Nuclear Information System (INIS)

    Voinov, A.V.

    1996-01-01

    The information about the level density of 156 Gd nucleus and strength functions of γ transitions extracted from two γ-cascade spectra of the 155 Gd (n,2γ) 156 Gd reaction is analyzed. The method of statistical simulation of γ-cascade intensity is applied for calculation of the main parameters of experimental spectra. The method is used to extract the information on the E1-radiative strength function of γ transitions and level density in the 156 Gd nucleus. It is shown that at an excitation energy above 3 MeV the level density of 156 Gd nucleus must decrease in comparison with that calculated within the Fermi gas model. Its is concluded that possible explanation of the observed effect is connected with the influence of pairing correlations on the level density in nuclei

  20. New TB treatments hiding in plain sight

    OpenAIRE

    Olive, Andrew J; Sassetti, Christopher M

    2014-01-01

    As tuberculosis (TB) toll is revised upward according to the WHO's last estimates, the lack of vaccine strategy and the lengthy antibiotic treatments that unfortunately promote the emergence of drug resistance are a major set back in the fight against this pathogen. In this issue of EMBO Molecular Medicine, Schiebler et?al (Mtb) propose a novel and compelling new approach to target Mycobacterium tuberculosis (Mtb) by pharmacologically stimulating intracellular mycobacteria clearance through a...

  1. Incidence of TB and HIV in Prospectively Followed Household Contacts of TB Index Patients in South Africa

    OpenAIRE

    van Schalkwyk, Cari; Variava, Ebrahim; Shapiro, Adrienne E.; Rakgokong, Modiehi; Masonoke, Katlego; Lebina, Limakatso; Welte, Alex; Martinson, Neil

    2014-01-01

    OBJECTIVE: To report the incidence rates of TB and HIV in household contacts of index patients diagnosed with TB. DESIGN: A prospective cohort study in the Matlosana sub-district of North West Province, South Africa. METHODS: Contacts of index TB patients received TB and HIV testing after counseling at their first household visit and were then followed up a year later, in 2010. TB or HIV diagnoses that occurred during the period were determined. RESULTS: For 2,377 household contacts, the over...

  2. Need for more TB vaccine field sites.

    Science.gov (United States)

    McShane, Helen

    2009-06-01

    Efforts to control the tuberculosis (TB) epidemic have been challenged by both the geographical overlap with the HIV pandemic, and the emergence of multi - and extensively - drug-resistant strains of Mycobacterium tuberculosis. There is, therefore, an urgent global need for an improved vaccine. However, the development of an improved vaccine is scientifically and logistically challenging. Immunological correlates or biomarkers of protection are not known and there is no perfect preclinical animal model with which to predict success in humans. Indeed, vaccine development in general is time-consuming and costly. One of the many road-blocks to the development of new TB vaccines is the availability of field sites that are suitable for large scale Phase IIb/III efficacy testing. Because disease incidence is low, even though prevalence is high, Phase IIb efficacy trials involve several thousand subjects, and require lengthy follow-up. Phase III licensure trials will need to be even larger, and are likely to require the involvement of multiple field sites. There is currently inadequate capacity within high-burden TB countries to conduct these essential trials. We need to invest now to expand current capacity if we are to reduce the time taken to develop new vaccines.

  3. ER2OWL: Generating OWL Ontology from ER Diagram

    Science.gov (United States)

    Fahad, Muhammad

    Ontology is the fundamental part of Semantic Web. The goal of W3C is to bring the web into (its full potential) a semantic web with reusing previous systems and artifacts. Most legacy systems have been documented in structural analysis and structured design (SASD), especially in simple or Extended ER Diagram (ERD). Such systems need up-gradation to become the part of semantic web. In this paper, we present ERD to OWL-DL ontology transformation rules at concrete level. These rules facilitate an easy and understandable transformation from ERD to OWL. The set of rules for transformation is tested on a structured analysis and design example. The framework provides OWL ontology for semantic web fundamental. This framework helps software engineers in upgrading the structured analysis and design artifact ERD, to components of semantic web. Moreover our transformation tool, ER2OWL, reduces the cost and time for building OWL ontologies with the reuse of existing entity relationship models.

  4. PODAAC-ERS13-IMWF0

    Data.gov (United States)

    National Aeronautics and Space Administration — The European Remote Sensing Satellite generation 2 (ERS-2) Level 3 Mean Wind Fields dataset is derived from the ERS-2 scatterometer data and is produced and...

  5. Endoplasmic Reticulum (ER Stress and Endocrine Disorders

    Directory of Open Access Journals (Sweden)

    Daisuke Ariyasu

    2017-02-01

    Full Text Available The endoplasmic reticulum (ER is the organelle where secretory and membrane proteins are synthesized and folded. Unfolded proteins that are retained within the ER can cause ER stress. Eukaryotic cells have a defense system called the “unfolded protein response” (UPR, which protects cells from ER stress. Cells undergo apoptosis when ER stress exceeds the capacity of the UPR, which has been revealed to cause human diseases. Although neurodegenerative diseases are well-known ER stress-related diseases, it has been discovered that endocrine diseases are also related to ER stress. In this review, we focus on ER stress-related human endocrine disorders. In addition to diabetes mellitus, which is well characterized, several relatively rare genetic disorders such as familial neurohypophyseal diabetes insipidus (FNDI, Wolfram syndrome, and isolated growth hormone deficiency type II (IGHD2 are discussed in this article.

  6. Extensively Drug-resistant Tuberculosis (XDR-TB): A daunting challenge to the current End TB Strategy and policy recommendations.

    Science.gov (United States)

    Rahman, Md Arifur; Sarkar, Atanu

    2017-07-01

    Extensively Drug-resistant Tuberculosis (XDR-TB) has emerged as one of the most formidable challenges to the End TB Strategy that has targeted a 95% reduction in TB deaths and 90% reduction in cases by 2035. Globally, there were an estimated 55,100 new XDR-TB cases in 2015 in 117 countries. However, only one in 30 XDR-TB cases had been reported so far. Drug susceptibility test (DST) is the mainstay for diagnosing XDR-TB, but the lack of laboratory facilities in the resource-limited endemic countries limit its uses. A few new drugs including bedaquiline and delamanid, have the potential to improve the efficiency of XDR-TB treatment, but the drugs have been included in 39 countries only. The costs of XDR-TB treatment are several folds higher than that of the MDR-TB. Despite the financing from the donors, there is an urgent need to fill the current funding gap of US$ 2 billion to ensure effective treatment and robust surveillance. In the review article we have addressed current update on XDR-TB, including surveillance, diagnosis and the interventions needed to treat and limit its spread, emphasis on extensive financial support for implementing of current recommendations to meet the goals of End TB Strategy. Copyright © 2017 Tuberculosis Association of India. Published by Elsevier B.V. All rights reserved.

  7. The study on the interaction between Tb(III) and ligand in Tb-acetylsalicylic acid complex and fluorescence mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Wu Wenru; Rong Yuzhi; Zhao Bo [Jiangsu Key Laboratory of Biofunctional Materials, College of Chemistry and Environmental Science, Nanjing Normal University, Nanjing, 210097 (China); Sun Peipei, E-mail: sunpeipei@njnu.edu.c [Jiangsu Key Laboratory of Biofunctional Materials, College of Chemistry and Environmental Science, Nanjing Normal University, Nanjing, 210097 (China); Huang Xiaohua, E-mail: huangxiaohua@njnu.edu.c [Jiangsu Key Laboratory of Biofunctional Materials, College of Chemistry and Environmental Science, Nanjing Normal University, Nanjing, 210097 (China)

    2010-01-15

    In this paper, a luminescent complex of terbium-acetylsalicylic acid (Tb-ASA) was studied for the first time using combination of the quantum chemical calculation, fluorescence spectroscopic method and X-ray photoelectron spectroscopy (XPS). The results from the quantum chemical calculation indicated that it is possible for the energy-transfer from ASA to Tb (III); Fluorescence spectroscopy demonstrated that there is an intramolecular energy-transfer from ASA to Tb with the efficiency (III) of about 87.9% under an excitation at 308 nm. The XPS indicated that the coordinate covalent bond between Tb and O existed in the complex of Tb-ASA leads to the effective energy transfer from ASA to Tb (III) because the energy transfer rate may be improved with reducing the distance between the ligand and Tb (III). The results will have important values for the studies of this type of complexes.

  8. Hvornår er man ung?

    DEFF Research Database (Denmark)

    Gundelach, Peter; Nørregård-Nielsen, Esther C.

    2002-01-01

    Hvornår er man ung, og hvornår er man voksen? Er der forskelle i befolkningens værdier i forhold til arbejde og politik, når det undersøges ud fra henholdsvis et alders- eller generationsperspektiv? Baseret på data fra den danske del af den internationale værdiundersøgelse vises at der er så store...

  9. Outcomes of TB treatment in HIV co-infected TB patients in Ethiopia: a cross-sectional analytic study

    Directory of Open Access Journals (Sweden)

    Solomon Ahmed Ali

    2016-11-01

    Full Text Available Abstract Background TB and HIV are the most prevalent communicable diseases of major public health importance in the populations of sub-Saharan African countries, and an estimated 30 % of HIV infected persons have dual infection with TB. TB is the leading cause of death in HIV infected individuals, and HIV co-infected TB patients have multiple individual, disease specific and treatment related factors that can adversely affect their treatment outcomes. There is lack of evidence on the individual patient outcomes of HIV co-infected TB patients who receive anti-TB treatment. It is relevant to understand the differential patient outcomes of HIV co-infected TB patients and identify the factors that are associated with these outcomes. Methods A comparative analysis was done on the data from a random sample of 575 TB patients who were enrolled for TB treatment from January 2013 to December 2013 at eight health facilities in Ethiopia. A descriptive analysis was done on the data, and chi-square test and logistic regression analysis was conducted to compare TB treatment outcomes based on HIV status and to identify factors associated with these outcomes. Results Out of a total of 575 TB patients enrolled into the study, 360 (62.6 % were non-HIV infected, 169 (29.4 % were HIV co-infected, and 46 (8 % had no documented HIV status. The overall treatment success rate was 91.5 % for all the study participants. HIV co-infected TB patients have a treatment success rate of 88.2 % compared with 93.6 % for non-HIV infected study participants (P = 0.03. HIV co-infected TB patients had a significantly higher rate (11.8 % versus 6.4 %, P = 0.03 of unfavourable outcomes. The cure rate was significantly lower (10.1 % versus 24.2 %, P = 0.001 and the death rate higher in HIV co-infected TB patients (8.3 % versus 2.5 %, P = 0.014. Age and TB classification were significantly associated with treatment outcome. No association was found with starting ART

  10. Role of Pr substitution as deoxygenation in suppression of superconductivity in GdPr-123 system

    Science.gov (United States)

    Yamani, Z.; Akhavan, M.

    1996-02-01

    Predominantly single phase polycrystalline Gd 1- xPr xBa 2Cu 3O 7- y (GdPr-123) samples with 0 ≤ x ≤ 1.0 have been prepared by standard solid state reaction technique and characterized by XRD. The electrical resistivity measurements show the suppression of superconductivity with increasing x. Two plateaus appear in the Tc versus x curve at x ≈ 0-0.05 and at x ≈ 0.15-0.25 followed by a decrease to zero at xcr ≈ 0.45, similar to the plateaus of Tc versus 7 - y curve at 7 - y ≈ 6.8 -7 and at 7 - y ≈ 6.55-6.75 in RBa 2Cu 3O 7 - y ( R-123) ( R: Y or rare earth except Ce, Pr, Pm, Tb) systems. The valency of Pr was determined by magnetization measurements in the temperature range 100 K to 250 K. This data indicates a mixed valence state for Pr ions with an effective magnetic moment μ ≈ 2.69 μB per Pr ion, which yields a valency for Pr of ≈ 3.86 +. For these systems, Tc( x) does not follow the Abrikosov-Gor'kov pair breaking theory. We suggest that the suppression of superconductivity by Pr-substitution can be explained by means of an effective increasing of the oxygen deficiency in the structure, in a similar way to what happens in an R-123 system, when 7 - y is decreased in a controlled manner. This implies that CuO 2 planes are responsible for superconductivity through the effect of chains.

  11. Magnetoelastic behaviour of Gd sub 5 Ge sub 4

    CERN Document Server

    Magen, C; Algarabel, P A; Marquina, C; Ibarra, M R

    2003-01-01

    A complete investigation of the complex magnetic behaviour of Gd sub 5 Ge sub 4 by means of linear thermal expansion and magnetostriction measurements (5-300 K, 0-120 kOe) has been carried out. Our results support the suggested existence in this system of a coupled crystallographic-magnetic transition from a Gd sub 5 Ge sub 4 -type Pnma (antiferromagnetic) to a Gd sub 5 Si sub 4 -type Pnma (ferromagnetic) state. Strong magnetoelastic effects are observed at the field-induced first-order magnetic-martensitic transformation. A revised magnetic and crystallographic H- T phase diagram is proposed.

  12. Magnetic transitions and thermomagnetic properties of GdCu6

    International Nuclear Information System (INIS)

    Chattopadhyay, M.K.; Arora, P.; Mondal, P.; Roy, S.B.

    2010-01-01

    We report results of dc magnetization and specific heat studies focusing on the paramagnetic to antiferromagnetic transition in GdCu 6 . These results clearly reveal the evidences of multiple magnetic transitions in GdCu 6 . In addition, a marked thermomagnetic irreversibility is observed in the temperature dependence of magnetization in low ( 6 is quite large in the temperature regime below 20 K, which indicates to the potential of GdCu 6 as a magnetic regenerator material for cryocooler related applications. Isothermal magnetic entropy change estimated from the results of magnetization and specific heat measurements shows a change in sign at the antiferromagnetic ordering temperature.

  13. Hvor automatiseret er den danske fremstillingsindustri?

    DEFF Research Database (Denmark)

    Kromann, Lene; Sørensen, Anders

    Denne første rapport i AIM-projektet viser at der er mulighed for yderligere automation i en stor del af de danske fremstillingsvirksomheder. Gennemsnitlig er kun 30% af produktionsprocessen i virksomhederne automatiseret. Det er især inspektion og eksekvering, som mange virksomheder mangler at a...

  14. En sang der er et overlevelsesudstyr

    DEFF Research Database (Denmark)

    Kock, Christian Erik J

    2015-01-01

    Fredmans Epistel N:o 81 er en af de Bellman-sange der oftest er blevet fortolket af sangere og grupper, og som synes at være blandt hans mest virkningsfulde. Hvad er dens virkning, og hvad beror den på? Læsningen her inddrager både ord og musik, lyd og tanke....

  15. Hvorfor er sygeplejersker usynlige i offentlige medier?

    DEFF Research Database (Denmark)

    Joensen, Annemi Lund; Hall, Elisabeth

    2015-01-01

    Når der er sygeplejerelevante emner til debat i de offentlige medier på Færøerne, bærer debatten præg af sygeplejerskers manglende deltagelse. Sygeplejerskerne er usynlige. Et eksempel på dette er en debat om besparelser inden for ældreomsorgen. Til trods for at besparelsen fik omfattende konsekv...

  16. Phantom and animal studies of a new hepatobiliary agent for MR imaging: comparison of Gd-DTPA-DeA with Gd-EOB-DTPA.

    Science.gov (United States)

    Yoshikawa, Kohki; Inoue, Yusuke; Akahane, Masaaki; Shimada, Morio; Itoh, Sayaka; Seno, Atsushi; Hayashi, Sanshin

    2003-08-01

    To investigate the characteristics of Gd-DTPA-DeA as a hepatobiliary contrast agent for MR imaging in comparison with those of Gd-EOB-DTPA. We undertook phantom experiments to assess T1 relaxivity for Gd-DTPA-DeA, Gd-EOB-DTPA, and Gd-DTPA in human plasma. For Gd-DTPA-DeA and Gd-EOB-DTPA, we evaluated the contrast effect in rats using an SPGR sequence. The contrast ratios of liver and abdominal aorta were measured up to 21 minutes after intravenous administration of the agents. Visualization of the bile duct and renal pelvis was also assessed. In human plasma, T1 relaxivity was similar for Gd-DTPA-DeA and Gd-EOB-DTPA, and higher than those for Gd-DTPA. Whereas the contrast ratio of liver peaked about five minutes after the injection of Gd-EOB-DTPA and was followed by a subsequent decline, a continuous rise was shown for Gd-DTPA-DeA, resulting in a larger maximal contrast effect. Contrast ratios of the abdominal aorta were larger for Gd-DTPA-DeA. Biliary excretion was observed for both agents but occurred earlier with Gd-EOB-DTPA. While renal excretion was shown for all rats three minutes after the injection of Gd-EOB-DTPA, it was not observed for Gd-DTPA-DeA. Gd-DTPA-DeA may be used as a hepatobiliary contrast agent and shows different pharmacokinetics from Gd-EOB-DTPA. Copyright 2003 Wiley-Liss, Inc.

  17. Thermodynamic calculation of Al-Gd and Al-Gd-Mg phase equilibria checked by key experiments

    International Nuclear Information System (INIS)

    Groebner, J.; Kevorkov, D.; Schmid-Fetzer, R.

    2001-01-01

    The binary Al-Gd and the ternary Al-Gd-Mg systems were calculated using the Calphad method. It is demonstrated that previous interpretation of ternary liquidus temperatures below 700 C must be related to other phase equilibria. The actual ternary liquidus temperatures are much higher, up to some 600 C above the previous interpretation in literature. They are widely governed by the high-melting compounds Al 2 Gd and Al 3 Gd with liquidus surfaces stretching far into the ternary system. A small number of key experiments in this work confirmed the calculated liquidus temperature and the phase relations. The available experimental data in literature fit excellently with the calculation in the binary Al-Gd system. In the ternary Al-Gd-Mg system, which is shown in several sections of the phase diagram, a good agreement can be observed too, considering the necessary reinterpretation of the liquidus temperatures suggested by Rokhlin et al. Ternary solubilities were not found experimentally. The ternary compound Al 4 GdMg (τ) forms in a ternary peritectic reaction at 761 C. (orig.)

  18. Lanthanide-activated Na5Gd9F32 nanocrystals precipitated from a borosilicate glass: Phase-separation-controlled crystallization and optical property

    International Nuclear Information System (INIS)

    Chen, Daqin; Wan, Zhongyi; Zhou, Yang; Chen, Yan; Yu, Hua; Lu, Hongwei; Ji, Zhenguo; Huang, Ping

    2015-01-01

    Highlights: • Na 5 Gd 9 F 32 nanocrystals embedded glass ceramics were fabricated for the first time. • Such glass ceramics were achieved by phase-separation-controlled crystallization. • Elemental mapping evidenced the segregation of activators into the Na 5 Gd 9 F 32 lattice. • Luminescent color could be tuned by controlling glass crystallization temperature. - Abstract: Lanthanide-activated cubic Na 5 Gd 9 F 32 nanocrystals were precipitated from a borosilicate glass with a specifically designed composition. The precursor glass is already phase-separated after melt-quenching, which is beneficial to the realization of the controllable glass crystallization for affording desirable size, morphology and activator partition. Elemental mapping in the scanning transmission electron microscopy evidenced that the segregation of lanthanide ions into the Na 5 Gd 9 F 32 lattice was in situ formed without the requirement of long-range ionic diffusion. Impressively, such fabricated glass ceramic co-doped with Yb 3+ /Er 3+ ions exhibited intense upconversion luminescence, which was about 500 times higher than that of the precursor glass, and its luminescent color could be easily tuned from red to green by controlling glass crystallization temperature. It is anticipated that such phase-separation synthesis strategy with precise control over nanostructure of glass ceramics offer a great opportunity to design other highly transparent nanocomposites with a wide range of tunable optical properties

  19. Tank 241-ER-311, grab samples, ER311-98-1, ER311-98-2, ER311-98-3 analytical results for the final report

    International Nuclear Information System (INIS)

    FULLER, R.K.

    1999-01-01

    This document is the final report for catch tank 241-ER-311 grab samples. Three grab samples ER311-98-1, ER311-98-2 and ER311-98-3 were taken from East riser of tank 241-ER-311 on August 4, 1998 and received by the 222-S Laboratory on August 4, 1998. Analyses were performed in accordance with the Compatibility Grab Sampling and Analysis Plan (TSAP) (Sasaki, 1998)and the Data Quality Objectives for Tank Farms Waste Compatibility Program (DQO) (Mulkey and Miller, 1997). The analytical results are presented in the data summary report (Table 1). No notification limits were exceeded

  20. Optimization of TB/HIV co-treatment in Ethiopian patients

    OpenAIRE

    Degu, Wondwossen Amogne

    2015-01-01

    Tuberculosis (TB) and HIV infection act with deadly synergy. HIV is the most important risk factor for latent TB reactivation and active TB progression following exposure or reinfection while TB accelerates HIV progression. TB is the most frequent cause of morbidity and mortality in HIV infection. Anti-TB therapy (ATT) must precede initiation of combination Antiretroviral Therapy (cART), TB being the most immediate threat. Undoubtedly cART benefits; however, important clinical ...

  1. Molecular detection of multi drug resistant tuberculosis (mdr-tb) in mdr-tb patients' attendant in north western pakistan

    International Nuclear Information System (INIS)

    Shah, T.; Hayat, A.; Shah, Z.; Hayat, A.; Khan, S.B.

    2017-01-01

    Objective: To determine the drugs susceptibility pattern of mycobacterium tuberculosis (M.TB) in multi-drug resistant tuberculosis (MDR-TB) patients' attendants in North Western, Pakistan. Study Design: Cross sectional study. Place and Duration of Study: This study was conducted at Peshawar Tuberculosis Research Laboratory (PTRL), Provincial TB Control Program Hayatabad Medical Complex Peshawar, (KP) from August 2013 to March 2014. Material and Methods: A cross sectional study in which four hundred and eighty sputum samples from MDR-TB patients' attendants were processed for the detection of M.TB through Ziehl-Neelsen staining, Lowenstein-Jensen, BACTEC MGIT-960 culture and line probe assay. Results: Out of 480 samples, 06 (2.1%) were found positive for M.TB through Ziehl-Neelsen staining while 10 (2.8%) were positive through LJ and BACTEC MGIT-960 culture. The 10 positive samples were further subjected to drugs susceptibility testing and line probes assay test to find out rifampicin, isoniazid, streptomycin and ethambutol resistant and it was found that 6 M.TB isolates were resistant while 4 were sensitive to rifampicin and isoniazid. Among the 6 resistant M.TB strains, 4 showed mutation in rpoB gene at 531, 516 and 526 codons. Conclusion: Majority of MDR-TB patients' attendants had drug-resistant tuberculosis and the rate of drug susceptible TB was low. (author)

  2. Incidence of TB and HIV in prospectively followed household contacts of TB index patients in South Africa.

    Directory of Open Access Journals (Sweden)

    Cari van Schalkwyk

    Full Text Available OBJECTIVE: To report the incidence rates of TB and HIV in household contacts of index patients diagnosed with TB. DESIGN: A prospective cohort study in the Matlosana sub-district of North West Province, South Africa. METHODS: Contacts of index TB patients received TB and HIV testing after counseling at their first household visit and were then followed up a year later, in 2010. TB or HIV diagnoses that occurred during the period were determined. RESULTS: For 2,377 household contacts, the overall observed TB incidence rate was 1.3 per 100 person years (95% CI 0.9-1.9/100py and TB incidence for individuals who were HIV-infected and HIV seronegative at baseline was 5.4/100py (95% CI 2.9-9.0/100py and 0.7/100py (95% CI 0.3-1.4/100py, respectively. The overall HIV incidence rate was 2.2/100py (95% CI 1.3-8.4/100py. CONCLUSIONS: In the year following a household case finding visit when household contacts were tested for TB and HIV, the incidence rate of both active TB and HIV infection was found to be extremely high. Clearly, implementing proven strategies to prevent HIV acquisition and preventing TB transmission and progression to disease remains a priority in settings such as South Africa.

  3. Neutronic analysis of Gd2O3 as burnable poison

    International Nuclear Information System (INIS)

    Lecot, C.A.

    1990-01-01

    For the reactors core design, the use of burnable poisons is one of the options for the control of in excess reactivity and the power form factor. As alternative procedures, the absorbing material may be included in pellets of an inert material or in fuel pellets. Besides, a cladding material and the locations of the fuel elements must be chosen for the first case. The CAREM reactor core design foresees the use of gadolinium oxide (Gd 2 O 3 ) as burnable poison. In this work, a comparative study was made, from the neutronic point of view, among the following alternatives for the poisons location: a) Gd 2 O 3 bars supports in alumina (Al 2 O 3 ), sheathed in steel; b) Gd 2 O 3 bars supports in alumina sheathed in Zry-4; c) Gd 2 O 3 in uranium dioxide (UO 2 ) fuel pellets. (Author) [es

  4. Electronic Structure of GdCuGe Intermetallic Compound

    Science.gov (United States)

    Lukoyanov, A. V.; Knyazev, Yu. V.; Kuz'min, Yu. I.

    2018-04-01

    The electronic structure of GdCuGe intermetallic compound has been studied. Spin-polarized energy spectrum calculations have been performed by the band method with allowance for strong electron correlations in the 4 f-shell of gadolinium ions. Antiferromagnetic ordering of GdCuGe at low temperatures has been obtained in a theoretical calculation, with the value of the effective magnetic moment of gadolinium ions reproduced in fair agreement with experimental data. The electronic density of states has been analyzed. An optical conductivity spectrum has been calculated for GdCuGe; it reveals specific features that are analogous to the ones discovered previously in the GdCuSi compound with a similar hexagonal structure.

  5. Treatment Outcomes of Patients with Multidrug-Resistant Tuberculosis (MDR- TB) Compared with Non-MDR-TB Infections in Peninsular Malaysia.

    Science.gov (United States)

    Elmi, Omar Salad; Hasan, Habsah; Abdullah, Sarimah; Mat Jeab, Mat Zuki; Ba, Zilfalil; Naing, Nyi Nyi

    2016-07-01

    Treating patients with multidrug-resistant tuberculosis (MDR-TB) strains is more complicated, complex, toxic, expensive, than treating patients with susceptible TB strains. This study aims to compare the treatment outcomes and potential factors associated between patients with MDR-TB and non MDR TB infections in peninsular Malaysia. This study was a retrospective cohort study. Data were collected from the medical records of all registered MDR-TB patients and Non-MDR-TB patients at five TB hospitals in peninsular Malaysia from January 2010 to January 2014. A total of 314 subjects were studied, including 105 MDR-TB cases and 209 non-MDR-TB. After TB treatment, 24.8% of the MDR-TB patients and 17.7% of non MDR TB relapsed; 17.1% of the MDR-TB patients and 16.3% of non MDR TB defaulted from TB treatment. A significant difference seen in treatment success rate 17.1% for MDR-TB; 63.1% for non MDR TB (P history of TB treatment, and presence of HIV infection.

  6. Linkage to care and treatment for TB and HIV among people newly diagnosed with TB or HIV-associated TB at a large, inner city South African hospital.

    Directory of Open Access Journals (Sweden)

    Yara Voss De Lima

    Full Text Available To assess the outcomes of linkage to TB and HIV care and identify risk factors for poor referral outcomes.Cohort study of TB patients diagnosed at an urban hospital.Linkage to care was determined by review of clinic files, national death register, and telephone contact, and classified as linked to care, delayed linkage to care (>7 days for TB treatment, >30 days for HIV care, or failed linkage to care. We performed log-binomial regression to identify patient and referral characteristics associated with poor referral outcomes.Among 593 TB patients, 23% failed linkage to TB treatment and 30.3% of the 77.0% who linked to care arrived late. Among 486 (86.9% HIV-infected TB patients, 38.3% failed linkage to HIV care, and 32% of the 61.7% who linked to care presented late. One in six HIV-infected patients failed linkage to both TB and HIV care. Only 20.2% of HIV-infected patients were referred to a single clinic for integrated care. A referral letter was present in 90.3%, but only 23.7% included HIV status and 18.8% CD4 cell count. Lack of education (RR 1.85 and low CD4 count (CD4≤50 vs. >250cells/mm(3; RR 1.66 were associated with failed linkage to TB care. Risk factors for failed linkage to HIV care were antiretroviral-naïve status (RR 1.29, and absence of referral letter with HIV or CD4 cell count (RR1.23.Linkage to TB/HIV care should be strengthened by communication of HIV and CD4 results, ART initiation during hospitalization and TB/HIV integration at primary care.

  7. Electron impact excitation of Gd XXXVII

    Energy Technology Data Exchange (ETDEWEB)

    Aggarwal, K.M.; Keenan, F.P. [Dept. of Pure and Applied Physics, Queen' s Univ., Belfast (United Kingdom); Norrington, P.H.; Bell, K.L. [Dept of Applied Maths. and Theoretical Physics, Queen' s Univ., Belfast (United Kingdom); Pert, G.J. [Dept. of Physics, York Univ., York (United Kingdom); Rose, S.J. [Plasma Physics Group, Rutherford Appleton Lab., Oxon (United Kingdom)

    2000-01-01

    Energy levels and radiative rates for transitions among the 107 fine-structure levels belonging to the (1s{sup 2}2s{sup 2}2p{sup 6}) 3s{sup 2}3p{sup 6}3d{sup 10}, 3s{sup 2}3p{sup 6}3d{sup 9}4l, 3s{sup 2}3p{sup 5}3d{sup 10}4l, and 3s3p{sup 6}3d{sup 10}4l configurations of Ni-like Gd XXXVII have been calculated using the GRASP code. The collision strengths have also been computed but among the lowest 59 levels only, at 4 representative energies of 200, 400, 600 and 800 Ryd, using the Dirac Atomic R-matrix code. Detailed calculations for collision strengths and rate coefficients are in progress. (author)

  8. Trial of MR cholangiopancreatography combined with Gd-DTPA

    Energy Technology Data Exchange (ETDEWEB)

    Ikeda, Koshi; Ha-Kawa, S.K.; Kurokawa, Hiroaki; Nakano, Yoshihisa; Tanaka, Yoshimasa [Kansai Medical Univ., Moriguchi, Osaka (Japan); Asakura, Tamaki; Maeda, Toshihiko; Ohshima, Taichi

    1997-08-01

    Gd-DTPA can be used as a negative contrast agent on T2-weighted images because of T2 shortening effect. Fast asymmetric spin echo (FASE) sequences were used on magnetic resonance cholangiopancreatography (MRCP). Precontrast images showed high signal intensity in choledochalpancreatic venous plexus, which aggravated visualization of the bile duct and pancreatic duct. Intravenous administration of Gd-DTPA reduced signal intensity in pericholedochal or peripancreatic small veins, and improved image quality of MRCP. (author)

  9. GdF in Hungary: the East in progress

    International Nuclear Information System (INIS)

    Anon.

    1996-01-01

    After Germany and the Czech Republic, Gaz de France (GdF) has decided to export its know-how and technologies about natural gas into Hungary. Thanks to the Hungarian privatization program started in 1995, GdF could obtain the major participation in the Degaz and Egaz companies, two out of the five local distribution companies, and controls 22% of the natural gas distribution in Hungary. (J.S.)

  10. Evaluation of hypothetical (153)Gd source for use in brachytherapy.

    Science.gov (United States)

    Ghorbani, Mahdi; Behmadi, Marziyeh

    2016-01-01

    The purpose of this work is to evaluate the dosimetric parameters of a hypothetical (153)Gd source for use in brachytherapy and comparison of the dosimetric parameters with those of (192)Ir and (125)I sources. Dose rate constant, the radial dose function and the two dimensional (2D) anisotropy function data for the hypothetical (153)Gd source were obtained by simulation of the source using MCNPX code and then were compared with the corresponding data reported by Enger et al. A comprehensive comparison between this hypothetical source and a (192)Ir source with similar geometry and a (125)I source was performed as well. Excellent agreement was shown between the results of the two studies. Dose rate constant values for the hypothetical (153)Gd, (192)Ir, (125)I sources are 1.173 cGyh(-1) U(-1), 1.044 cGyh(-1) U(-1), 0.925 cGyh(-1) U(-1), respectively. Radial dose function for the hypothetical (153)Gd source has an increasing trend, while (192)Ir has more uniform and (125)I has more rapidly falling off radial dose functions. 2D anisotropy functions for these three sources indicate that, except at 0.5 cm distance, (192)Ir and (125)I have more isotropic trends as compared to the (153)Gd source. A more uniform radial dose function, and 2D anisotropy functions with more isotropy, a much higher specific activity are advantages of (192)Ir source over (153)Gd. However, a longer half-life of (153)Gd source compared to the other two sources, and lower energy of the source with respect to (192)Ir are advantages of using (153)Gd in brachytherapy versus (192)Ir source.

  11. Fixed Dose Combination for TB treatment

    Directory of Open Access Journals (Sweden)

    Tjandra Y. Aditama

    2003-06-01

    Full Text Available According to the World Health Organization, a third of the world’s population is infected with tuberculosis. The disease is responsible for nearly 2 million deaths each year and over 8 million were developing active diseases. Moreover, according to WHO (2000, tuberculosis deaths are estimated to increase to 35 million between 2000-2020. The majority of tuberculosis patients worldwide are still treated with single drugs, or with 2-drug fixed-dose combinations (FDCs. To improve tuberculosis treatment, 2- and 3-drug FDCs were recommended by the World Health Organization (WHO as part of the DOTS strategy. Since 1999 a 4-drug FDC was included on the WHO Model List of Essential Drugs. Today, FDCs are important tools to further improve the quality of care for people with TB, and accelerate DOTS expansion to reach the global TB control targets. Fixed dose combination TB drugs could simplifies both treatment and management of drug supply, and may prevent the emergence of drug resistance .Prevention of drug resistance is just one of the potential benefits of the use of FDCs. FDCs simplify administration of drugs by reducing the number of pills a patient takes each day and decreasing the risk of incorrect prescriptions. Most tuberculosis patients need only take 3–4 FDCs tablets per day during the intensive phase of treatment, instead of the 15–16 tablets per day that is common with single-drug formulations It is much simpler to explain to patients that they need to take four tablets of the same type and colour, rather than a mixture of tablets of different shapes, colours and sizes. Also, the chance of taking an incomplete combination of drugs is eliminated, since the four essential drugs are combined into one tablet. FDCs are also simpler for care-givers as they minimize the risk of confusion. Finally, drug procurement, in all its components (stock management, shipping, distribution, is simplified by FDCs. Adverse reactions to drugs are not more

  12. Photodarkening in Tb(3+)-doped phosphosilicate and germanosilicate optical fibers.

    Science.gov (United States)

    Atkins, G R; Carter, A L

    1994-06-15

    The presence of Tb(3+) is found to sensitize greatly phosphosilicate and germanosilicate optical fibers to photodarkening when they are exposed to 488-nm light. The darkening is a three-photon process and may involve the photoionization of Tb(3+) to Tb(4+). This sensitivity raises the possibility of side writing refractive-index gratings into silica-based optical fibers with 488-nm light.

  13. Radiation damage in CaF2: Gd

    International Nuclear Information System (INIS)

    Prado, L.

    1979-01-01

    Calcium fluoride crystals doped with Gd 3+ at four different concentrations were irradiated at room temperature. The damage produced by radiation and the primary and secondary effects as well were studied by optical spectroscopy. The increase in optical absorption (with loss of transparency) varied from sample as a function of concentration and dose. The coloration curves showed an evolution from two to three radiation damage steps when going from a pure to the most Gd 3+ concentrated sample. The obtained spectra were analysed at characteristic wave lenghts of electronic defects (photochromic centers, F and its aggregates) and of Gd 3+ and Gd 2+ defects. As a result of the radiation damage the valence change (Gd 3+ →Gd 2+ ) and its reversible character under thermal activation were directly observed. These effects were correlated with other observed effects such as the room temperature luminescence after the irradiation ceased. The non radiative F centers formation from the interaction of holes and photochromic centers was also observed and analysed. A thermal activation study of the several defects responsible for the different absorption bands was made. Values of activation energies were obtained as expected for the kind of defects involved in these processes [pt

  14. Investigation of nanocrystalline Gd films loaded with hydrogen

    KAUST Repository

    Hruška, Petr

    2015-01-01

    The present work reports on microstructure studies of hydrogen-loaded nanocrystalline Gd films prepared by cold cathode beam sputtering on sapphire (112¯0) substrates. The Gd films were electrochemically step-by-step charged with hydrogen and the structural development with increasing concentration of absorbed hydrogen was studied by transmission electron microscopy and in-situ   X-ray diffraction using synchrotron radiation. The relaxation of hydrogen-induced stresses was examined by acoustic emission measurements. In the low concentration range absorbed hydrogen occupies preferentially vacancy-like defects at GBs typical for nanocrystalline films. With increasing hydrogen concentration hydrogen starts to occupy interstitial sites. At the solid solution limit the grains gradually transform into the ββ-phase (GdH2). Finally at high hydrogen concentrations xH>2.0xH>2.0 H/Gd, the film structure becomes almost completely amorphous. Contrary to bulk Gd specimens, the formation of the γγ-phase (GdH3) was not observed in this work.

  15. A new entry in GdNCT. The nanodosimetry

    International Nuclear Information System (INIS)

    Cerullo, Nicola; Bufalino, Domenico; Esposito, Juan

    2006-01-01

    The GdNCT is a recently proposed therapy, mainly based on the action of Auger and IC electrons, generated by 157 Gd after neutron activation. The energy carried out by these electrons is limited to about 1% of total energy of the reaction, but due to high electron LET, if the emitter is bound to DNA, their action is very effective. Some Gd compounds have the property to be bound to DNA. Therefore the evaluation of the DNA damage caused by the Gd-emitted electrons is a key issue. The DNA damage is due to almost double strand breaks (DSB) in the DNA double helix chain. The dimensions concerned are of the order of 2 to 3 nm. Therefore, in the study of GdNCT, besides macro and micro, we must use the new 'nanodosimetry', based on particle interactions in the nanometric sites. A general review on GdNCT state of the art and on the nanometric Monte Carlo computing techniques, applied to a DNA model, is here presented. (author)

  16. ALnS2:RE (A=K, Rb; Ln=La, Gd, Lu, Y): New optical materials family

    International Nuclear Information System (INIS)

    Jarý, V.; Havlák, L.; Bárta, J.; Mihóková, E.; Buryi, M.; Nikl, M.

    2016-01-01

    In the presented review paper, new potentially interesting material family, RE-doped ternary sulfides ALnS 2 (RE=Ce, Pr, Sm, Eu, Tb, Tm; A=Rb, K; Ln=La, Gd, Lu, Y) is discussed. Their synthesis is described and the structural and optical properties, characterized by methods of X-ray diffraction, time-resolved luminescence spectroscopy and electron paramagnetic resonance, are summarized and reviewed especially with respect to the influence of their composition. All samples discussed were synthesized in the form of transparent crystalline hexagonal platelets by chemical reaction under the flow of hydrogen sulfide. Their luminescence characteristics, including absorption, radioluminescence, photoluminescence excitation and emission spectra and decay kinetics, were measured and evaluated in a broad temperature (8–800 K) and concentration (0.002–20% of dopants) range. The application potential of mentioned compounds in the field of white LED solid state lightings or X-ray phosphors is thoroughly discussed. - Highlights: • RE-doped ALnS 2 (A=K, Rb; Ln=La, Gd, Lu, Y) were synthesized. • Their optical characteristics are summarized. • Concentration and temperature dependences of luminescence features investigated. • EPR technique is employed to explain Eu 2+ incorporation into KLuS 2 host. • The application potential in white LED and X-ray phosphors is discussed.

  17. Non-adherence to anti-TB drugs among TB/HIV co-infected patients ...

    African Journals Online (AJOL)

    Background: Non-adherence to treatment remains a major obstacle to efficient tuberculosis control in developing countries. The dual infection of Tuberculosis and HIV presents further adherence problems because of high pill burden and adverse effects. This poses a risk of increased multi-drug resistant TB. However, the ...

  18. Delay in commencing treatment for MDR TB at a specialised TB ...

    African Journals Online (AJOL)

    Culture and drug sensitivity testing (DST) takes 8 weeks or longer to obtain results while line probe assays (LPAs) can give a result in hours. LPAs and the GeneXpert MTB/Rif (GX) are ground-breaking discoveries for TB diagnosis. However, they are not easily accessible or available to those needing it, so culture and ...

  19. Magnetic Interactions in Tb and Tb-10% Ho from Inelastic Neutron Scattering

    DEFF Research Database (Denmark)

    Bjerrum Møller, Hans; Houmann, Jens Christian Gylden; Mackintosh, A.R.

    1968-01-01

    The magnon dispersion relations and lifetimes have been measured in Tb and a Tb‐10% Ho alloy by inelastic neutron scattering, in regions of both ferromagnetic and spiral ordering. In the ferromagnetic phase, the magnon energy is generally finite at zero wavevector and rises quadratically at low q...

  20. Extensively drug-resistant tuberculosis (XDR-TB) in Morocco.

    Science.gov (United States)

    Ennassiri, Wifak; Jaouhari, Sanae; Cherki, Wafa; Charof, Reda; Filali-Maltouf, Abdelkarim; Lahlou, Ouafae

    2017-12-01

    Extensively drug-resistant tuberculosis (XDR-TB) has recently been identified as a major global health threat. The aim of this study was to evaluate the presence of XDR-TB among Mycobacterium tuberculosis isolates in Morocco and its association with demographic, clinical and epidemiological features. A total of 524 patients from the Moroccan National Tuberculosis Reference Laboratory, representative of all of the geographic regions, were subject to first-line drug susceptibility testing (DST). Subsequently, 155 isolates found to be multidrug-resistant tuberculosis (MDR-TB) underwent second-line DST. Moreover, to enhance our understanding of the genetic basis of these drug-resistant strains, drug resistance-associated mutations were investigated in isolates either identified as pre-XDR- and XDR-TB or suspected resistant using the GenoType ® MTBDRsl V1.0 assay. In this study, 4 (2.6%) XDR-TB and 18 (11.6%) pre-XDR-TB isolates were identified. Agreement between the MTBDRsl assay results and phenotypic DST was 95.2% for ofloxacin, 81.0% for kanamycin and 95.2% for amikacin. To the best of our knowledge, this is the first study to evaluate the frequency of XDR-TB in Morocco. These results highlight the need to reinforce the TB management policy in Morocco with regard to control and detection strategies in order to prevent further spread of XDR-TB isolates. Copyright © 2017. Published by Elsevier Ltd.

  1. Chest Radiographs for Pediatric TB Diagnosis: Interrater Agreement and Utility

    Directory of Open Access Journals (Sweden)

    G. Kaguthi

    2014-01-01

    Full Text Available The chest radiograph (CXR is considered a key diagnostic tool for pediatric tuberculosis (TB in clinical management and endpoint determination in TB vaccine trials. We set out to compare interrater agreement for TB diagnosis in western Kenya. A pediatric pulmonologist and radiologist (experts, a medical officer (M.O, and four clinical officers (C.Os with basic training in pediatric CXR reading blindly assessed CXRs of infants who were TB suspects in a cohort study. C.Os had access to clinical findings for patient management. Weighted kappa scores summarized interrater agreement on lymphadenopathy and abnormalities consistent with TB. Sensitivity and specificity of raters were determined using microbiologically confirmed TB as the gold standard (n=8. A total of 691 radiographs were reviewed. Agreement on abnormalities consistent with TB was poor; k=0.14 (95% CI: 0.10–0.18 and on lymphadenopathy moderate k=0.26 (95% CI: 0.18–0.36. M.O [75% (95% CI: 34.9%–96.8%] and C.Os [63% (95% CI: 24.5%–91.5%] had high sensitivity for culture confirmed TB. TB vaccine trials utilizing expert agreement on CXR as a nonmicrobiologically confirmed endpoint will have reduced specificity and will underestimate vaccine efficacy. C.Os detected many of the bacteriologically confirmed cases; however, this must be interpreted cautiously as they were unblinded to clinical features.

  2. Rotating disk atomization of Gd and Gd-Y for hydrogen liquefaction via magnetocaloric cooling

    Energy Technology Data Exchange (ETDEWEB)

    Slinger, Tyler [Iowa State Univ., Ames, IA (United States)

    2016-12-17

    In order to enable liquid hydrogen fuel cell technologies for vehicles the cost of hydrogen liquefaction should be lowered. The current method of hydrogen liquefaction is the Claude cycle that has a figure of merit (FOM) of 0.3-0.35. New magnetocaloric hydrogen liquefaction devices have been proposed with a FOM>0.5, which is a significant improvement. A significant hurdle to realizing these devices is the synthesis of spherical rare earth based alloy powders of 200μm in diameter. In this study a centrifugal atomization method that used a rotating disk with a rotating oil quench bath was developed to make gadolinium and gadolinium-yttrium spheres. The composition of the spherical powders included pure Gd and Gd0.91Y0.09. The effect of atomization parameters, such as superheat, melt properties, disk shape, disk speed, and melt system materials and design, were investigated on the size distribution and morphology of the resulting spheres. The carbon, nitrogen, and oxygen impurity levels also were analyzed and compared with the magnetic performance of the alloys. The magnetic properties of the charge material as well as the resulting powders were measured using a vibrating sample magnetometer. The saturation magnetization and Curie temperature were the target properties for the resulting spheres. These values were compared with measurements taken on the charge material in order to investigate the effect of atomization processing on the alloys.

  3. The isothermal section (500 C) of the Gd-Cu-Ni ternary phase diagram

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Huaiying [Guangxi Univ., Nanning (China). Mater. Sci. Inst.; Zhuang Yinghong [Guangxi Univ., Nanning (China). Mater. Sci. Inst.; Gu Zhengfei [Guilin Electrical Equipment Scientific Research Institute, Guilin (China)

    1995-04-15

    The isothermal section (500 C) of the Gd-Cu-Ni ([Gd]{<=}33.3 at.%) ternary phase diagram was determined using differential thermal analysis, optical microscopy, X-ray diffraction and electron microprobe techniques. This partial isothermal section consists of 12 single-phase regions, 24 two-phase regions and 12 three-phase regions. The 12 single-phase regions include one ternary compound (Gd(Cu{sub 1-x}Ni{sub x}){sub 3}, x=0.2-0.46), four Gd-Cu compounds (GdCu{sub 2}, Gd{sub 2}Cu{sub 9}, GdCu{sub 5}, GdCu{sub 6}), six Gd-Ni compounds (GdNi{sub 2}, GdNi{sub 3}, Gd{sub 2}Ni{sub 7}, GdNi{sub 4}, GdNi{sub 5}, Gd{sub 2}Ni{sub 17}) and the {alpha}-(Cu,Ni) solid solution. ((orig.))

  4. Patients direct costs to undergo TB diagnosis.

    Science.gov (United States)

    de Cuevas, Rachel M Anderson; Lawson, Lovett; Al-Sonboli, Najla; Al-Aghbari, Nasher; Arbide, Isabel; Sherchand, Jeevan B; Nnamdi, Emenyonu E; Aseffa, Abraham; Yassin, Mohammed A; Abdurrahman, Saddiq T; Obasanya, Joshua; Olanrewaju, Oladimeji; Datiko, Daniel; Theobald, Sally J; Ramsay, Andrew; Squire, S Bertel; Cuevas, Luis E

    2016-03-24

    A major impediment to the treatment of TB is a diagnostic process that requires multiple visits. Descriptions of patient costs associated with diagnosis use different protocols and are not comparable. We aimed to describe the direct costs incurred by adults attending TB diagnostic centres in four countries and factors associated with expenditure for diagnosis. Surveys of 2225 adults attending smear-microscopy centres in Nigeria, Nepal, Ethiopia and Yemen. Adults >18 years with cough >2 weeks were enrolled prospectively. Direct costs were quantified using structured questionnaires. Patients with costs >75(th) quartile were considered to have high expenditure (cases) and compared with patients with costs <75(th) quartile to identify factors associated with high expenditure. The most significant expenses were due to clinic fees and transport. Most participants attended the centres with companions. High expenditure was associated with attending with company, residing in rural areas/other towns and illiteracy. The costs incurred by patients are substantial and share common patterns across countries. Removing user fees, transparent charging policies and reimbursing clinic expenses would reduce the poverty-inducing effects of direct diagnostic costs. In locations with limited resources, support could be prioritised for those most at risk of high expenditure; those who are illiterate, attend the service with company and rural residents.

  5. Characteristics and programme-defined treatment outcomes among childhood tuberculosis (TB patients under the national TB programme in Delhi.

    Directory of Open Access Journals (Sweden)

    Srinath Satyanarayana

    Full Text Available BACKGROUND: Childhood tuberculosis (TB patients under India's Revised National TB Control Programme (RNTCP are managed using diagnostic algorithms and directly observed treatment with intermittent thrice-weekly short-course treatment regimens for 6-8 months. The assignment into pre-treatment weight bands leads to drug doses (milligram per kilogram that are lower than current World Health Organization (WHO guidelines for some patients. OBJECTIVES: The main aim of our study was to describe the baseline characteristics and treatment outcomes reported under RNTCP for registered childhood (age <15 years TB patients in Delhi. Additionally, we compared the reported programmatic treatment completion rates between children treated as per WHO recommended anti-TB drug doses with those children treated with anti-TB drug doses below that recommended in WHO guidelines. METHODS: For this cross-sectional retrospective study, we reviewed programme records of all 1089 TB patients aged <15 years registered for TB treatment from January to June, 2008 in 6 randomly selected districts of Delhi. WHO disease classification and treatment outcome definitions are used by RNTCP, and these were extracted as reported in programme records. RESULTS AND CONCLUSIONS: Among 1074 patients with records available, 651 (61% were females, 122 (11% were <5 years of age, 1000 (93% were new cases, and 680 (63% had extra-pulmonary TB (EP-TB--most commonly peripheral lymph node disease [310 (46%]. Among 394 pulmonary TB (PTB cases, 165 (42% were sputum smear-positive. The overall reported treatment completion rate was 95%. Similar reported treatment completion rates were found in all subgroups assessed, including those patients whose drug dosages were lower than that currently recommended by WHO. Further studies are needed to assess the reasons for the low proportion of under-5 years of age TB case notifications, address challenges in reaching all childhood TB patients by RNTCP, the

  6. Coupling of frustrated ising spins to the magnetic cycloid in multiferroic TbMnO3

    NARCIS (Netherlands)

    Prokhnenko, O.; Feyerherm, R.; Mostovoy, M.; Aliouane, N.; Dudzik, E.; Maljuk, A.; Argyriou, D. N.

    2007-01-01

    We report on diffraction measurements on multiferroic TbMnO3 which demonstrate that the Tb- and Mn-magnetic orders are coupled below the ferroelectric transition T-FE = 28 K. For T Tb and Mn are locked so that tau(Tb) = tau(Mn), while below T-N(Tb) =

  7. ER Stress and Lipid Metabolism in Adipocytes

    Directory of Open Access Journals (Sweden)

    Beth S. Zha

    2012-01-01

    Full Text Available The role of endoplasmic reticulum (ER stress is a rapidly emerging field of interest in the pathogenesis of metabolic diseases. Recent studies have shown that chronic activation of ER stress is closely linked to dysregulation of lipid metabolism in several metabolically important cells including hepatocytes, macrophages, β-cells, and adipocytes. Adipocytes are one of the major cell types involved in the pathogenesis of the metabolic syndrome. Recent advances in dissecting the cellular and molecular mechanisms involved in the regulation of adipogenesis and lipid metabolism indicate that activation of ER stress plays a central role in regulating adipocyte function. In this paper, we discuss the current understanding of the potential role of ER stress in lipid metabolism in adipocytes. In addition, we touch upon the interaction of ER stress and autophagy as well as inflammation. Inhibition of ER stress has the potential of decreasing the pathology in adipose tissue that is seen with energy overbalance.

  8. Endoplasmic reticulum: ER stress regulates mitochondrial bioenergetics

    Science.gov (United States)

    Bravo, Roberto; Gutierrez, Tomás; Paredes, Felipe; Gatica, Damián; Rodriguez, Andrea E.; Pedrozo, Zully; Chiong, Mario; Parra, Valentina; Quest, Andrew F.G.; Rothermel, Beverly A.; Lavandero, Sergio

    2014-01-01

    Endoplasmic reticulum (ER) stress activates an adaptive unfolded protein response (UPR) that facilitates cellular repair, however, under prolonged ER stress, the UPR can ultimately trigger apoptosis thereby terminating damaged cells. The molecular mechanisms responsible for execution of the cell death program are relatively well characterized, but the metabolic events taking place during the adaptive phase of ER stress remain largely undefined. Here we discuss emerging evidence regarding the metabolic changes that occur during the onset of ER stress and how ER influences mitochondrial function through mechanisms involving calcium transfer, thereby facilitating cellular adaptation. Finally, we highlight how dysregulation of ER–mitochondrial calcium homeostasis during prolonged ER stress is emerging as a novel mechanism implicated in the onset of metabolic disorders. PMID:22064245

  9. Management of MDR-TB in HIV co-infected patients in Eastern Europe: Results from the TB:HIV study.

    Science.gov (United States)

    Efsen, A M W; Schultze, A; Miller, R F; Panteleev, A; Skrahin, A; Podlekareva, D N; Miro, J M; Girardi, E; Furrer, H; Losso, M H; Toibaro, J; Caylà, J A; Mocroft, A; Lundgren, J D; Post, F A; Kirk, O

    2018-01-01

    Mortality among HIV patients with tuberculosis (TB) remains high in Eastern Europe (EE), but details of TB and HIV management remain scarce. In this prospective study, we describe the TB treatment regimens of patients with multi-drug resistant (MDR) TB and use of antiretroviral therapy (ART). A total of 105 HIV-positive patients had MDR-TB (including 33 with extensive drug resistance) and 130 pan-susceptible TB. Adequate initial TB treatment was provided for 8% of patients with MDR-TB compared with 80% of those with pan-susceptible TB. By twelve months, an estimated 57.3% (95%CI 41.5-74.1) of MDR-TB patients had started adequate treatment. While 67% received ART, HIV-RNA suppression was demonstrated in only 23%. Our results show that internationally recommended MDR-TB treatment regimens were infrequently used and that ART use and viral suppression was well below the target of 90%, reflecting the challenging patient population and the environment in which health care is provided. Urgent improvement of management of patients with TB/HIV in EE, in particular for those with MDR-TB, is needed and includes widespread access to rapid TB diagnostics, better access to and use of second-line TB drugs, timely ART initiation with viral load monitoring, and integration of TB/HIV care. Copyright © 2017 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

  10. HIV screening among TB patients and level of antiretroviral therapy ...

    African Journals Online (AJOL)

    The aim of this study was to assess the prevalence of HIV among TB patients and initiation of ART and provision of CPT for TB/HIV co-infected patients in Hawassa university referral hospital. Methods: A five year document ... Data analysis was done by using SPSS version 20 software. Bivariate and multivariate logistic ...

  11. The effects of Tb 3+ doping concentration on luminescence ...

    Indian Academy of Sciences (India)

    reported that the particle size, shape, crystallinity, etc., sig- nificantly affect the luminescence properties of Tb3+ ion.16. In 2014, the authors present ab initio theoretical study of the 4f8 and 4f75d manifolds of Tb3+-doped BaF2 cubic sites, gives the calculated electronic structure and spectro- scopic parameters.12 On the ...

  12. 46 CFR 30.10-11 - Coastwise-TB/C.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Coastwise-TB/C. 30.10-11 Section 30.10-11 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS GENERAL PROVISIONS Definitions § 30.10-11 Coastwise—TB/C. Under this designation shall be included all tank vessels normally navigating the waters of any...

  13. 46 CFR 30.10-61 - Rivers-TB/R.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Rivers-TB/R. 30.10-61 Section 30.10-61 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS GENERAL PROVISIONS Definitions § 30.10-61 Rivers—TB/R. Under this designation shall be included all tank vessels whose navigation is restricted to...

  14. When students become patients: TB disease among medical ...

    African Journals Online (AJOL)

    Background. Medical students acquire latent tuberculosis (TB) infection at a rate of 23 cases/100 person-years. The frequency and impact of occupational TB disease in this population are unknown. Methods. A self-administered questionnaire was distributed via email and social media to current medical students and ...

  15. EDITORIAL South Africa and national TB control: Are we making ...

    African Journals Online (AJOL)

    The analysis of the ten leading underlying natural causes of death showed that six of the top ten ... A systematic review on TB and poverty identified the contribution of patient costs in sub-Saharan Africa. The authors reported that. TB patients in sub-Saharan Africa incur both substantial direct and indirect costs before, during ...

  16. Prevalence and management out comes of anti TB drugs induced ...

    African Journals Online (AJOL)

    Patients and Methods: All TB patients admitted in the Hospital during the study period are the source of population, the study groups were been selected by detecting the possible confounding factors for jaundice. Base line LFT before anti TB initiation was determined before developed jaundice. Those patients, whom the ...

  17. 46 CFR 31.20-1 - Waters-TB/ALL.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Waters-TB/ALL. 31.20-1 Section 31.20-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS INSPECTION AND CERTIFICATION Waters Operated Over § 31.20-1 Waters—TB/ALL. The certificate of inspection shall show the waters over which the tank vessel...

  18. When students become patients: TB disease among medical ...

    African Journals Online (AJOL)

    access article is distributed under. Creative Commons licence CC-BY-NC 4.0. Background. Medical students acquire latent tuberculosis (TB) infection at a rate of 23 cases/100 person-years. The frequency and impact of occupational TB disease ...

  19. The social determinants of tuberculosis and their association with TB ...

    African Journals Online (AJOL)

    Progress made in TB control through the implementation of the DOTS strategy, has been retarded by factors such as poverty, the HIV pandemic and the advent of multidrug resistant tuberculosis. There is currently an increasing shift in TB control ...

  20. 8__Aisha_Detection ofMDR-TB

    African Journals Online (AJOL)

    User

    Among the MDR-TB cases rifampicin resistance was associated with rpoB WT gene and rpoB MUT gene in 100% and 62% of the ... diagnosis of TB patients, and proper treatment and management of the infected cases to minimize the spread and ..... in an amino acid change and concluded that this is one of the reasons ...

  1. 46 CFR 30.10-45 - Ocean-TB/O.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Ocean-TB/O. 30.10-45 Section 30.10-45 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS GENERAL PROVISIONS Definitions § 30.10-45 Ocean—TB/O. Under this designation shall be included all tank vessels normally navigating the waters of any ocean or...

  2. Rapid assessment of a National Tuberculosis (TB) Control ...

    African Journals Online (AJOL)

    infectious activities. Such activities include smoking, large alcohol intake which weakens immunity, spraying of cars and handling various chemicals. The incidence of TB amongst children and teenagers from 1 to 20 years are low: TB cases was 2.2% in age group 0-10 years and 9.9% in 11-20 years. This may suggest that.

  3. Antiferromagnetism in a 20% Ho-80% Tb alloy single crystal

    DEFF Research Database (Denmark)

    Lebech, Bente

    1968-01-01

    20% Ho-80% Tb exhibits two magnetic phases, similar to those of Tb. The spiral turn angle varies from 31.1° to 21.4°. A minimum effective spin for the occurrence of stable simple ferromagnetic structure at low temperatures is predicted....

  4. Not just pretty pictures: Geographical Information Systems in TB ...

    African Journals Online (AJOL)

    Geographical Information Systems (GIS) is becoming a useful tool in disease control by health planners. However little is known about its potential in tuberculosis (TB) control. In 2000 the National TB Programme (NTP) in Malawi assessed its usefulness. Routinely collected case-finding data from the 3 previous years (1997 ...

  5. Confinement in the management of drug-resistant TB: The ...

    African Journals Online (AJOL)

    In the context of expanding TB and HIV epidemics in South Africa, the decision to enforce non-voluntary admission for XDR TB raises many ethical and human rights dilemmas, principally because it trades off the human rights of individuals against the public good. However, the dichotomy may also involve competing rights ...

  6. Synergistic effect of Al and Gd on enhancement of mechanical properties of magnesium alloys

    Directory of Open Access Journals (Sweden)

    Bita Pourbahari

    2017-04-01

    Full Text Available The effect of Gd/Al ratio on the properties of as-cast Mg-Gd-Al-Zn alloys was investigated by changing the chemical composition from that of AZ61 to GZ61. At the ratio of 1, the Al2Gd phase becomes predominant and Mg17Al12 is hardly seen in the microstructure. As a potent inoculant, the Al2Gd phase resulted in intense grain refinement and enhancement of strength, ductility and toughness. For instance, the tensile strength and elongation to failure of Mg-3Gd-3Al-1Zn alloy were enhanced by ~4% and 180% compared with those of AZ61 alloy, respectively. However, at high Gd/Al ratios, the Al2Gd phase was replaced by (Mg,Al3Gd and Mg5Gd phases and very large grain sizes were achieved, which led to poor tensile properties and the appearance of cleavage facets on the fracture surfaces. Therefore, it can be deduced that the presence of Gd and Al, in appropriate amounts to reach Gd/Al ratio of ~ 1, is required for the achievement of grain refinement, good ductility, high strength, and the appearance of ductile fracture surfaces in the Mg-Gd-Al-Zn system. Conclusively, the Mg-Gd-Al-Zn alloys can be considered as a new class of structural magnesium alloy and it is superior to both AZ (Mg-Al-Zn and GZ (Mg-Gd-Zn series of alloys.

  7. Photoluminescent layered Y/Er silicates

    International Nuclear Information System (INIS)

    Kostova, Mariya H.; Ananias, Duarte; Carlos, Luis D.; Rocha, Joao

    2008-01-01

    The synthesis of new layered rare-earth silicates K 3 [Y 1-a Er a Si 3 O 8 (OH) 2 ] (AV-22 materials) has been reported. The photoluminescence properties of Y/Er-AV-22 and the material resulting from its thermal degradation, K 3 [Y 1-a Er a Si 3 O 9 ] (Y/Er-AV-23), have been studied and compared. Both materials have a similar chemical makeup and structures sharing analogous building blocks, hence providing a unique opportunity for rationalising the evolution of the photoluminescence properties of lanthanide silicates across dimensionality

  8. Er moral bare noget vi leger?

    DEFF Research Database (Denmark)

    Thomsen, Frej Klem

    2014-01-01

    Hvis man er skeptiker, så er moral nemlig altid kun et udtryk for psykologi og kultur, også når det handler om for eksempel misbrug af børn i Tønder-sagen eller terror-angreb i Madrid, London og Mumbai .......Hvis man er skeptiker, så er moral nemlig altid kun et udtryk for psykologi og kultur, også når det handler om for eksempel misbrug af børn i Tønder-sagen eller terror-angreb i Madrid, London og Mumbai ....

  9. Er virksomheder deres sociale ansvar voksent?

    DEFF Research Database (Denmark)

    Øhrgaard, Per

    2018-01-01

    Eftertanken. Virksomheder er i dag ramt af en CSR-bølge. Men hvis definitionen af, hvad et samfundsmæssigt ansvar er, glider over på virksomhedernes hænder, glider det væk fra alle os andre.......Eftertanken. Virksomheder er i dag ramt af en CSR-bølge. Men hvis definitionen af, hvad et samfundsmæssigt ansvar er, glider over på virksomhedernes hænder, glider det væk fra alle os andre....

  10. Der er ingen gode mennesker i Hundestad

    DEFF Research Database (Denmark)

    Nord, Johan Christian

    2015-01-01

    Lars von Trier sig selv, at han er kulturradikal. Men hans film fortæller en anden historie. I dem flænses alle illusioner - også kulturradikalismen. Netop derfor er han stor - meget større end ham de kaldte Store Klaus......Lars von Trier sig selv, at han er kulturradikal. Men hans film fortæller en anden historie. I dem flænses alle illusioner - også kulturradikalismen. Netop derfor er han stor - meget større end ham de kaldte Store Klaus...

  11. The Characteristics of TB Epidemic and TB/HIV Co-Infection Epidemic: A 2007-2013 Retrospective Study in Urumqi, Xinjiang Province, China.

    Directory of Open Access Journals (Sweden)

    Wang Wei

    Full Text Available This study was aimed to find out epidemiologic characteristic of tuberculosis (TB cases, and Human Immunodeficiency Virus (HIV positive cases among TB patients (TB/HIV co-infection through demographic, temporal, and spatial study in Urumqi.Descriptive statistics and multivariate logistic regression were applied to identify the epidemiologic characteristics and risk factors of TB epidemic and TB/HIV co-infection epidemic. All addresses of each TB case, TB/HIV co-infection case, and administrative street were transformed into geographical coordinate. Subsequently, the geocoded address for 82 streets was transformed into a dot map used as the basis of spatial datasets. In addition, the paper also used quantile map and the spatial scan statistic in order to identify the spatial distribution and spatial clusters of TB epidemic and TB/HIV co-infection epidemic.There was a declining trend of the notification rates of TB epidemic from 2007 to 2009, as well as a rising trend from 2010 to 2013. However, the notification rates of TB/HIV co-infection epidemic showed a rising trend from 2007 to 2010, and a declining trend from 2011 to 2013. Moreover, a significant share of TB epidemic and TB/HIV co-infection epidemic happened between the age of 15 to 45 years old, indicating an increase in risk of TB and TB/HIV infection. It is worth noting that the risk of HIV infection for male TB patients was 2.947 times (95% CI [2.178, 3.988] than that of female patients. Han ethnicity and Uygur ethnicity in urban region accounted for a large proportion of total TB and TB/HIV co-infection cases. Most of the TB cases of minorities in Urumqi showed a statistically significant increase in risk of HIV infection than Han ethnicity in Urumqi. In addition, the spatial distribution of TB epidemic and TB/HIV co-infection epidemic was highly skewed. Most of the local clusters were located in urban area and rural-urban continuum where showed an increase in risk of TB and TB

  12. Investigation on the magnetocaloric effect in TbN compound

    Energy Technology Data Exchange (ETDEWEB)

    Ranke, P.J. von, E-mail: von.ranke@uol.com.br [Instituto de Física, Universidade do Estado do Rio de Janeiro—UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil); Alvarenga, T.S.T.; Nóbrega, E.P.; Alho, B.P.; Ribeiro, P.O. [Instituto de Física, Universidade do Estado do Rio de Janeiro—UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil); Carvalho, A. Magnus G. [Divisão de Metrologia de Materiais (DIMAT), Instituto Nacional de Metrologia, Normalização e Qualidade Industrial (INMETRO), Duque de Caxias, RJ 25250-020 (Brazil); Sousa, V.S.R. de; Caldas, A.; Oliveira, N.A. de [Instituto de Física, Universidade do Estado do Rio de Janeiro—UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil)

    2013-09-15

    One of the biggest challenges in materials science is to understand the microscopic mechanisms responsible in storage and release material entropy. TbN compound, which presents non-degeneracy in ground state, was studied and the calculated magnetocaloric effect is in good agreement with the recent experimental data. Also inverse magnetocaloric effect and spin reorientation transition were predicted in TbN. The theoretical investigations were carried out using a Hamiltonian, which includes the crystalline electrical field, Zeeman and exchange interactions. - Highlights: • Theoretical description of the magnetocaloric effect in TbN. • Influence of the crystalline electrical field anisotropy on TbN. • Predictions of inverse and anomalous magnetocaloric effect in TbN.

  13. A world of cities and the end of TB.

    Science.gov (United States)

    Prasad, Amit; Ross, Alex; Rosenberg, Paul; Dye, Christopher

    2016-03-01

    The WHO's End TB Strategy aims to reduce TB deaths by 95% and incidence by 90% between 2015 and 2035. As the world rapidly urbanizes, more people could have access to better infrastructure and services to help combat poverty and infectious diseases, including TB. And yet large numbers of people now live in overcrowded slums, with poor access to urban health services, amplifying the burden of TB. An alignment of the Sustainable Development Goals (SDGs) for health and for urban development provides an opportunity to accelerate the overall decline in infection and disease, and to create cities free of TB. © The Author 2016. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene.

  14. Gd-HOPO Based High Relaxivity MRI Contrast Agents

    Energy Technology Data Exchange (ETDEWEB)

    Datta, Ankona; Raymond, Kenneth

    2008-11-06

    Tris-bidentate HOPO-based ligands developed in our laboratory were designed to complement the coordination preferences of Gd{sup 3+}, especially its oxophilicity. The HOPO ligands provide a hexadentate coordination environment for Gd{sup 3+} in which all he donor atoms are oxygen. Because Gd{sup 3+} favors eight or nine coordination, this design provides two to three open sites for inner-sphere water molecules. These water molecules rapidly exchange with bulk solution, hence affecting the relaxation rates of bulk water olecules. The parameters affecting the efficiency of these contrast agents have been tuned to improve contrast while still maintaining a high thermodynamic stability for Gd{sup 3+} binding. The Gd- HOPO-based contrast agents surpass current commercially available agents ecause of a higher number of inner-sphere water molecules, rapid exchange of inner-sphere water molecules via an associative mechanism, and a long electronic relaxation time. The contrast enhancement provided by these agents is at least twice that of commercial contrast gents, which are based on polyaminocarboxylate ligands.

  15. Epi-thermal neutron diffraction of Gd alloy, (3)

    International Nuclear Information System (INIS)

    Watanabe, Noboru; Ishikawa, Yoshikazu; Sekine, Hisashi; Suzuki, Michio; Fujii, Hironobu.

    1975-01-01

    Epi-thermal neutron diffraction of Gd alloy was studied. A single crystal of GdZn was made by the Bridgman's method, and the degree of order was 1.00. One of the epi-thermal neutron diffraction patterns from the GdZn single crystal is shown. The nuclear scattering amplitude of Gd was obtained as bsub(Gd)=(1.15 +- 0.15) x 10 -12 cm, which is in good agreement with the value obtained from the comparison with the magnetic diffraction of Gdsub(0.9)Ysub(0.1). The epi-thermal neutron diffraction of Gdsub(0.85)Thsub(0.15) was also studied. The magnetic satellite line was clearly seen at low temperature. Higher order satellite line could not be observed. The magnetic structures in which the satellite is observed at are proper screw, cycloid, transverse sine wave and conical structures. The possibility of the conical structure was eliminated by the observed diffraction patterns at room temperature and at 80 0 K. The magnetic structure factors for the other three structures were obtained. At present, it is unable to determine the magnetic structure for Gdsub(0.85)Thsub(0.15). (Kato, T.)

  16. Large magnetocaloric effect of GdNiAl2 compound

    International Nuclear Information System (INIS)

    Dembele, S.N.; Ma, Z.; Shang, Y.F.; Fu, H.; Balfour, E.A.; Hadimani, R.L.; Jiles, D.C.; Teng, B.H.; Luo, Y.

    2015-01-01

    This paper presents the structure, magnetic properties, and magnetocaloric effect of the polycrystalline compound GdNiAl 2 . Powder X-ray diffraction (XRD) measurement and Rietveld refinement revealed that GdNiAl 2 alloy is CuMgAl 2 -type phase structure with about 1 wt% GdNi 2 Al 3 secondary phase. Magnetic measurements suggest that the compound is ferromagnetic and undergoes a second-order phase transition near 28 K. The maximum value of magnetic entropy change reaches 16.0 J/kg K for an applied magnetic field change of 0–50 kOe and the relative cooling power was 6.4×10 2 J/kg. It is a promising candidate as a magnetocaloric material working near liquid hydrogen temperature (~20 K) exhibiting large relative cooling power. - Highlights: • Preferred orientation with axis of [010] was found in the GdNiAl 2 compound. • The ΔS Mmax and the RCP are 16.0 J/kg K and 640 J/kg, respectively, for ΔH=50 kOe. • Relative low rare earth content in GdNiAl 2 comparing with other candidates

  17. Remanent magnetization of amorphous La--Gd--Au alloys with high Gd content

    Energy Technology Data Exchange (ETDEWEB)

    Poon, S.J.; Durand, J.

    1977-04-01

    Results of bulk magnetic measurements are reported for splat-cooled amorphous alloys (La/sub 100-x/Gd/sub x/)/sub 80/Au/sub 20/ over the concentrated region between the dilute (x less than or equal to 1 at.%) and the ferromagnetic range (x > 70 at.%). For x less than or equal to 40 at.% alloys, low field susceptibility maxima occur at temperatures proportional to x, and the reduced remanent magnetization M/sub rs/(T)/x depends only on the reduced temperature T/x. Our results are analyzed in the spirit of a phenomenological model of uncompensated magnetic clouds. The interplay of the RKKY interaction and of the anisotropic dipolar forces is sufficient to account for the order of magnitude of the remanent magnetization for x less than or equal to 40 alloys.

  18. Electron paramagnetic resonance of Gd3+ in TlGdSe2

    International Nuclear Information System (INIS)

    Duczmal, M.; Mosiniewicz-Szablewska, E.; Pokrzywnicki, S.

    2003-01-01

    Electron paramagnetic resonance has been studied on the polycrystalline sample of the layer compound TlGdSe 2 . When the temperature is lowered from room temperature the linewidth reaches a shallow minimum near 60 K and then decreases rapidly below 15 K. From the two-dimensional molecular field model two exchange constants J 1 and J 2 with the nearest and next nearest neighbors were estimated. The calculated high-temperature limit of the linewidth (341 mT) is in fair agreement with the experimental value (314 mT). It may be slightly improved after taking into account the preferred orientation of the sample. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  19. Hva er det med Irma?

    Directory of Open Access Journals (Sweden)

    Anne Beate Reinertsen

    2016-10-01

    Full Text Available Abstract: This article is about formative quality assessment in a posthuman or newmaterial perspective; embodied knowledges.  Theory and method are written together in immanence to envision complexity.  The aim and scope of the article is to follow the flow of events Irma produces opening up for affirmative poetical critique praxis. Quality is forwarded as an intensity and force in a moment only.  The moment is therefore the only structure of the text, as moving quality. The intention and inner logic of the text is therefore designed to work against fixed definitions and conceptualizations of what quality and quality assessment is.  This way I hope to show what posthuman and newmaterial approaches can contribute with to build cultures of innovation in which quality is assessed and produces again and again. They put differences to work and open up for creating moments of educational justice. Sammendrag: Artikkelen handler om kvalitetsvurdering i et nymaterielt perspektiv: Kroppslig kunnskap og viten. Teori og metode skrives sammen i immanent samtidighet for å gi et bilde på kompleksitet. Både hensikt og mål med artikkelen er å følge den flyten som Irma som hendelse eller event produserer, for å åpne opp potensialitet for en bekreftende eller affirmativ poetiserende kritikkpraksis og en ny forståelse av- og vurdering for kvalitet. Kvalitet skrives fram som en hendelse, intensitet eller kraft i et øyeblikk. Øyeblikket er derfor tekstens eneste og bærende struktur, som kvalitet i bevegelse. Tekstens indre logikk har slik til hensikt å motvirke forsøk på å skape definerte, faste eller bestemte oppfatninger av hva kvalitet er og hvordan kvalitet kan vurderes. På denne måten håper jeg å vise hva nymaterielle perspektiver kan gjøre for å bygge kulturer for innovasjon hvor kvalitet vurderes og produseres igjen og igjen. De setter forskjellighet i bevegelse og åpner opp for å skape rettferdige utdanningsøyeblikk.

  20. Risk factors for poor treatment outcomes in patients with MDR-TB and XDR-TB in China: retrospective multi-center investigation.

    Science.gov (United States)

    Tang, Shenjie; Tan, Shouyong; Yao, Lan; Li, Fujian; Li, Li; Guo, Xinzhi; Liu, Yidian; Hao, Xiaohui; Li, Yanqiong; Ding, Xiuxiu; Zhang, Zhanjun; Tong, Li; Huang, Jianan

    2013-01-01

    The treatment of patients with MDR- and XDR-TB is usually more complex, toxic and costly and less effective than treatment of other forms of TB. However, there is little information available on risk factors for poor outcomes in patients with MDR- and XDR-TB in China. We retrospectively analyzed the clinical records of HIV-negative TB Patients with culture-proven MDR- or XDR-TB who were registered from July 2006 to June 2011 at five large-scale Tuberculosis Specialized Hospitals in China. Among 1662 HIV-seronegative TB cases which were culture-positive for M. tuberculosis complex and had positive sputum-smear microscopy results, 965 cases (58.1%) were DR-TB, and 586 cases (35.3%) were classified as having MDR-TB, accounting for 60.7% of DR-TB. 169 cases (10.2%) were XDR-TB, accounting for 17.5% of DR-TB, 28.8% of MDR-TB. The MDR-TB patients were divided into XDR-TB group (n=169) and other MDR-TB group (non-XDR MDR-TB) (n=417). In total, 240 patients (40.95%) had treatment success, and 346 (59.05%) had poor treatment outcomes. The treatment success rate in other MDR-TB group was 52.2%, significantly higher than that in the XDR-TB group (13%, PChina.The presence of extensive drug resistance, low BMI, hypoalbuminemia, comorbidity, cavitary disease and previous anti-TB treatment are independent prognostic factors for poor outcome in patients with MDR-TB.

  1. Ungdomslitteratur former(er) sig

    DEFF Research Database (Denmark)

    Henkel, Ayoe Qvist

    2016-01-01

    Igennem en 'mediesensitiv' analyse af romanen "Akavet" af Ronnie Andersen (2014) og perspektivering til andre aktuelle romaner for og med unge undersøger artiklen, hvordan ungdomslitteratur udvikler sig i dialog med digitale og mediebaserede impulser, og hvilke konsekvenser for udsigelserne om...... ungdomsliv og ungdomslitteraturens æstetik og mulige egenart, denne udvikling har. Artiklen baserer sig på en materialitetstilgang særligt inspireret af N. Katherine Hayles, som ikke tidligere har fået opmærksomhed i læsninger af ungdomslitteratur eller i diskussioner af ungdomslitteraturens mulige egenart......, at ungdomslitteratur drejer sig om unges udviklingsproces fra barndom og til voksenhed og dermed skildrer en overgang præget af linearitet, modning og vækst. Artiklen konkluderer, at der er ungdomslitteratur, der realiseres på andre præmisser, og Akavet kan ses som eksponent for en bevægelse fra ungdomslitteratur som...

  2. Vidensamfundet - det er sund fornuft

    DEFF Research Database (Denmark)

    Pedersen, Esther Oluffa

    2008-01-01

      Artiklen analyserer ophavet til det meget ombruste slogan 'fra tanke til faktura' i Danmarks Erhvervsråds rapport Vidensamfundet - en begrebsafklaring fra 2003 og i skyggerapporten udformet af CO-industri og Dansk Industri (DI) i notatet Fra forskning til faktura fra sommeren 2001. Med baggrund i...... disse rapporter og i regeringens efterfølgende udspil til en omstrukturering af de danske universiteter belyses, hvorledes strategiske udspil fra erhvervsinteressenter bliver konkret politik. Nærværende eksempel viser, hvordan CO-industris og DIs agenda på universitetsområdet meget direkte og i løbet af...... meget kort tid har opnået at blive udmøntet som dansk lov. Sigtet med artiklen er (1) at give en kritisk kommentar til den definition af viden, som ligger til grund for sloganet 'fra tanke til faktura'. Rapporterne analyseres for at belyse den ideologiske baggrund, der ligger bag de strategisk...

  3. Antiferromagnetic ordering in GdRhIn{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Latka, K.; Rams, M. [Marian Smoluchowski Inst. of Physics, Jagiellonian Univ., Krakow (Poland); Kmiec, R.; Pacyna, A.W. [Henryk Niewodniczanski Inst. of Nuclear Physics, Polish Academy of Sciences, Krakow (Poland); Zaremba, V.I. [Inorganic Chemistry Dept., Ivan Franko National Univ. of Lviv, Lviv (Ukraine); Inst. fuer Anorganische und Analytische Chemie, Westfaelische Wilhelms-Univ. Muenster (Germany); Poettgen, R. [Inst. fuer Anorganische und Analytische Chemie, Westfaelische Wilhelms-Univ. Muenster (Germany)

    2004-09-01

    A polycrystalline sample of tetragonal GdRhIn{sub 5} (HoCoGa{sub 5} type, space group P4/mmm) was obtained by induction melting of the elements in a glassy carbon crucible in a water-cooled sample chamber and subsequent annealing at 670 K. X-ray powder data yielded the cell parameters a = 460.65(7), c = 743.52(12) pm. The magnetic and electronic properties of GdRhIn{sub 5} have been studied by magnetic susceptibility, electrical resistivity, and {sup 155}Gd Moessbauer spectroscopic measurements. Antiferromagnetic ordering is detected at 41.0(2) K. The results are discussed using a simple molecular field approximation. (orig.)

  4. Diagnostic value of Gd-DTPA in mediastinal masses

    International Nuclear Information System (INIS)

    Hahn, D.; Naegele, M.; Seelos, K.; Lissner, J.A.

    1987-01-01

    Thirty-three patients with different mediastinal masses were examined with a 1.0-T Magnetom using Gd-DTPA. In all patients short spin echo sequences without and with Gd-DTPA as well as fast imaging sequences with reduced echo delay times or different flip angles in gradient echoes were compared. The relative enhancement rate in tumor tissue, fat, muscle and bone marrow was evaluate by signal-intensity measurement before and after application of contrast medium. The uptake of contrast medium in benign masses and inflammatory diseases was significantly lower than in malignant masses. The good enhancement of mediastinal tumors allowed a better differentiation of the inner structure of the tumor. A better differential diagnosis of malignant tumors could not be done by measuring the signal intensity enhancement rate because of overlapping values. Gd-DTPA-enhanced MR imaging may, however, be helpful in follow-up studies in patients with malignant lymphomas

  5. Measurement of internal conversion electrons from Gd neutron capture

    Energy Technology Data Exchange (ETDEWEB)

    Kandlakunta, P. [Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH 43210 (United States); Cao, L.R., E-mail: cao.152@osu.edu [Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH 43210 (United States); Mulligan, P. [Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH 43210 (United States)

    2013-03-21

    Gadolinium (Gd) is a suitable material for neutron conversion because of its superior neutron absorption cross-section. However, the principal secondary particles that generate electron-hole pairs in a semiconductor detector after Gd neutron capture are low-energy internal conversion (IC) electrons. We measured the IC electron spectrum due to Gd neutron capture by using a thermal neutron beam and a digitizer-based multidetector spectroscopy. We also discussed the effective use of the IC electrons in the context of a twin-detector design and the associated gamma-ray rejection issues. Extensive simulations of the spectra of IC electrons and gamma rays agreed well with the experimental results; both types of results support the feasibility of the proposed n–γ separation method.

  6. Magnetic transition in Co/(Gd-Co) multilayers

    International Nuclear Information System (INIS)

    Svalov, A.V.; Fernandez, A.; Barandiaran, J.M.; Vas'kovskiy, V.O.; Orue, I.; Tejedor, M.; Kurlyandskaya, G.V.

    2008-01-01

    [Co/Gd 0.36 Co 0.64 ] 4 /Co multilayers with Co termination layer have been prepared by rf sputtering. They form macroscopic ferrimagnets with a compensation temperature (T comp ) determined by the thickness ratio of the layers. In low fields the magnetization of Co and Gd-Co layers are along the axis of the applied field. Increasing field makes the moments of both the Co and Gd-Co layers deviate from the axis of the field giving rise to a transition into a twisted state. These magnetic transitions were studied by vibrating sample magnetometer (VSM), magneto-optic Kerr effect and magnetoresistance measurements at various temperatures. The nucleation and evolution of surface- and bulk-twisted magnetic states were also observed in these multilayers

  7. Effect of Gd substitution on structure and spectroscopic properties of (Lu,Gd)2O3:Eu ceramic scintillator

    Science.gov (United States)

    Cao, Maoqing; Hu, Zewang; Ivanov, Maxim; Dai, Jiawei; Li, Chaoyu; Kou, Huamin; Shi, Yun; Chen, Haohong; Xu, Jiayue; Pan, Yubai; Li, Jiang

    2018-02-01

    In this paper, (Lu1-xGdx)2O3:Eu (x = 0, 0.1, 0.3, 0.5, 0.7, 0.9) ceramics were consolidated by the solid-state reaction method combined with vacuum sintering without sintering aids. We investigated the effect of the varying contents of Gd2O3 on the structure and spectroscopic properties of (Lu1-xGdx)2O3:Eu ceramics. X-ray diffraction (XRD) patterns indicate that proper amount of Gd2O3 can incorporate well with Lu2O3 and form Lu2O3-Gd2O3 solid solution. However, excessive Gd3+-doping in Lu2O3 will lead to the cubic phase transforming into monoclinic even hexagonal phase. The Gd3+ substitution no more than 50% of Lu2O3 enhances the radioluminescence, and reduces the fluorescence lifetime. Transmittance, photoluminescence, and radiation damage of the (Lu1-xGdx)2O3:Eu scintillation ceramics were also studied.

  8. Trend of childhood TB case notification in Lagos, Nigeria, 2011–2014

    OpenAIRE

    Daniel, Olusoji James; Adejumo, Olusola Adedeji; Abdur-Razzaq, Husseine A.; Ebunoluwa, Jaiyesimi O.

    2015-01-01

    Background: Childhood tuberculosis (TB) has been neglected by national TB programs in sub-Saharan Africa because of the emphasis on adult smear-positive TB cases. About 80,000 HIV children die from TB, and over 550,000 childhood TB cases occur annually, representing 6% of the global TB burden, making TB an important cause of morbidity and mortality in children. Thus, this study assessed the trend of childhood TB cases notified in Lagos, Nigeria from 2011 to 2014. Methods: Retrospective da...

  9. Application Values of T-SPOT.TB in Clinical Rapid Diagnosis of Tuberculosis.

    Science.gov (United States)

    Zhu, Feng; Ou, Qinfang; Zheng, Jian

    2018-01-01

    This paper aims to explore the application value of tuberculosis-specific enzyme-linked immunospot assay (T-SPOT.TB) in the diagnosis of tuberculosis. Fifty one patients with tuberculosis (TB) admitted to Wuxi No.5 People's Hospital, Wuxi, China from June 2015 to June 2017 were selected as the TB group, and 40 patients without tuberculosis admitted in the same period were randomly selected as the non-TB group. Patients in the two groups received T-SPOT.TB, TB antibody (TB-Ab) test and mycobacterium TB deoxyribonucleic acid (TB-DNA) test, and the results were compared. Comparisons of the sensitivity of the three methods showed that the sensitivity of T-SPOT.TB was the highest, followed by TB-DNA from sputum samples, and that of TB-Ab was the lowest. The specificity of TB-Ab was the highest, followed by T-SPOT.TB, and that of TB-DNA from sputum samples was the lowest. In the receiver operating characteristic (ROC) curve analysis, the area under curve (AUC) of T-SPOT.TB (0.896) was the highest, followed by TB-DNA from sputum samples (0.772), and that of sputum smears (0.698) was the lowest. T-SPOT.TB can quickly and accurately determine the presence of tuberculosis infection, and it is a non-invasive examination, which can further assist in the diagnosis and guide the treatment.

  10. Behavior of Gd-DTPA in simulated bank filtration

    Energy Technology Data Exchange (ETDEWEB)

    Moeller, Peter, E-mail: pemoe@gfz-potsdam.de [Freie Universitaet Berlin, Malteserstr. 74-100, AB Hydrogeologie, 12249 Berlin (Germany)] [Helmholtz Zentrum Potsdam, Deutsches GeoForschungsZentrum, Telegrafenberg, 14473 Potsdam (Germany); Knappe, Andrea [Freie Universitaet Berlin, Malteserstr. 74-100, AB Hydrogeologie, 12249 Berlin (Germany); Dulski, Peter [Helmholtz Zentrum Potsdam, Deutsches GeoForschungsZentrum, Telegrafenberg, 14473 Potsdam (Germany); Pekdeger, Asaf [Freie Universitaet Berlin, Malteserstr. 74-100, AB Hydrogeologie, 12249 Berlin (Germany)

    2011-01-15

    Research highlights: {yields} Gd-DTPA and similar products are common pollutants in surface and groundwater and prove to be a reliable monitor for mixing of groundwater with surface water loaded with effluents from sewage treatment plants. {yields} Within a 30 m column filled with Pleistocene sand Gd-DTPA is reduced by 16% only within one month time by transmetallation. {yields} Artificial bank filtration is not very effective in reducing Gd-DTPA in infiltrating water. - Abstract: The behavior of Gd-DTPA during bank filtration was simulated in a 30 m column filled with Pleistocene sand and flushed by surface water from a lakeside in Berlin, Germany. The surface water is about a 1:1 mixture of river water and effluents from a sewage treatment plant. Throughout 34 days this water was continuously spiked with Gd-DTPA at a level of 60 {mu}g/L. The broad plateau of the Gd-DTPA pulse declined by 15.4% within 34 days by transmetallation. Nine percentage of the total decline is caused by Y and rare earth elements; the remaining part is attributed to Cu{sup 2+} which is the most influential metal in surface water. All other metals also contributing to transmetallation are combined with Cu to Cu equivalents because only the rate constant of transmetallation of Cu{sup 2+} is known. The analytical results of the column effluents prove the pseudo-first-order kinetics of transmetallation based on reversible sorption of metals by pools in the column sediment and disprove biodegradation at noticeable levels. The mass ratio of water to tracer is <10{sup 10}.

  11. "Det man siger er man selv..."

    DEFF Research Database (Denmark)

    Næsby, Torben; Nørgaard, Britta; Uddholm, Mats

    forhold, der er hermeneutisk, strukturelt og relationelt bestemt. Praksisviden kan ikke være objektiv i gængs forstand, men det behøver ikke at diskvalificere denne viden. Forståelse er altid knyttet til den sag og bundet til den situation man står overfor og i som professionel og som menneske....

  12. Er der en underviser til stede?

    DEFF Research Database (Denmark)

    Christiansen, René Boyer; Nortvig, Anne-Mette; Rosenlund, Lea Tilde

    2015-01-01

    I de senere år er MOOC (Massive Open Online Courses) blevet en faktor på uddannelsesområdet. MOOC-forskning er et forholdsvist nyt felt, men har inden for de seneste 2-3 år udviklet sig med hastige skridt (Liyanagunawardena et al. 2013, Bayne & Ross 2014). En stor del af denne forskning har haft...

  13. Coronavirus infection, ER stress and Apoptosis

    Directory of Open Access Journals (Sweden)

    TO SING eFUNG

    2014-06-01

    Full Text Available The replication of coronavirus, a family of important animal and human pathogens, is closely associated with the cellular membrane compartments, especially the endoplasmic reticulum (ER. Coronavirus infection of cultured cells was previously shown to cause ER stress and induce the unfolded protein response (UPR, a process that aims to restore the ER homeostasis by global translation shutdown and increasing the ER folding capacity. However under prolonged ER stress, UPR can also induce apoptotic cell death. Accumulating evidence from recent studies has shown that induction of ER stress and UPR may constitute a major aspect of coronavirus-host interaction. Activation of the three branches of UPR modulates a wide variety of signaling pathways, such as mitogen-activated protein (MAP kinases activation, autophagy, apoptosis and innate immune response. ER stress and UPR activation may therefore contribute significantly to the viral replication and pathogenesis during coronavirus infection. In this review, we summarize current knowledge on coronavirus-induced ER stress and UPR activation, with emphasis on their cross-talking to apoptotic signaling.

  14. Er formen blevet vigtigst i politik?

    DEFF Research Database (Denmark)

    Etemadi, Maziar Haghpaidar

    2005-01-01

    RETORIK: Retorikken er kunsten at tage ordet - skriftligt eller mundtligt - og udtrykke sig smukt og velformuleret. Gorgias (ca. 490-ca. 390 f. Kr.) fra Leontinoi på Sicilien betragtes som ophavsmanden til den første endelige formulering af retorikkens virke og muligheder: "Talen er en mægtig...

  15. Multikulturalisme er en ny slags Apartheid

    DEFF Research Database (Denmark)

    Dyrberg, Torben Bech

    2016-01-01

    I en ny antologi retter forfatterne et kritisk lys mod forsvarerne af multikulturalisme. Og det er der god grund til, mener en af bogens redaktører. For den store gruppe, der hylder multikulturen, glemmer i al dens godhed, at de samtidig er med til at undergrave demokratiet og styrke uheldige mag...

  16. First-principles study of rare-earth (RE) cobaltites (RE=Nd,Sm,Gd,Dy,Er,Lu)

    Science.gov (United States)

    Topsakal, M.; Wentzcovitch, R. M.

    2014-12-01

    The lanthanide series of the periodic table comprises 15 members ranging from Lanthanum (La) to Lutetium (Lu). Although they are more abundant than silver, and some of them are more abundant than lead, they are known as rare-earth (RE) elements. The "rare" in their name refers to the difficulty of obtaining the pure elements, not to their abundances in nature. They are never found as free metals in the Earth's crust and do not exist as pure minerals. Using first-principles plane-wave calculations, we investigate the structural and electronic properties of rare-earth cobaltites (RECoO3). Structurally consistent Hubbard U treatment was shown to essential for proper description of strongly correlated cobalt-d electrons. We successfully capture the experimentally observed structural trends and give first-principles insights on interesting phenomena related with the cobalt spin state change. It was demonstrated that increase of crystal-field splitting energy between eg-t2g orbitals and shrinking of unoccupied σ*-bonding eg bands are responsible for the increase of onset spin-state transition temperature along the series.

  17. Defect induced visible-light-activated near-infrared emissions in Gd3-x-y-zYbxBiyErzGa5O12

    Science.gov (United States)

    Tong, Liping; Saito, Katsuhiko; Guo, Qixin; Zhou, Han; Fan, Tongxiang; Zhang, Di

    2017-11-01

    Visible-light-activated near-infrared luminescent materials are promising photoluminescent materials due to their convenience and low cost. Crystal defects can seriously affect the performance of luminescent materials, and better understanding of the complexity of the structural disorder and electronic structures of such materials opens up new possibilities in luminescent material development. In this work, we successfully design a novel, effective, visible-light-activated near-infrared luminescent Gd3Ga5O12: 4.2%Yb3+, 8.4%Er3+, and 4.2%Bi3+ system based on first principles. This exhibits strong emission intensity and high luminous efficiency (0.993) and also has a lifetime (7.002 ms) that is at least twice as long as the longest lifetime reported in published papers. We utilize density functional theory with an effective LSDA + U method to study the structural properties of Gd3-x-y-zGa5O12: xYb3+, yBi3+, zEr3+ (GGG: Yb3+, Bi3+, Er3+). The d and f electron orbits of rare-earth ions are considered for an effective Hund exchange. Detailed analysis reveals that GGG: 4.2%Yb3+, 8.4%Er3+, 4.2%Bi3+ has the smallest cell volume because of the strong covalent bonds of Bi-O, Er-O, and Yb-O. Bi 3d is a hybridized state that acts as sensitizing ions during the process of luminescence in GGG: Yb3+, Bi3+, Er3+. Together with experimental and theoretical results, we analyze the influence of defects on emission intensity. The locations of Yb3+, Er3+, and Bi3+ are determined by X-ray absorption fine structure measurements, which are in agreement with the model constructed using first principles. This work may provide innovative guidance for the design of high-performance visible-light-activated near-infrared luminophores based on calculations and a new methodology for application of coherent laser radar and optical communication.

  18. Immigrants and health system challenges to TB control in Oman

    Directory of Open Access Journals (Sweden)

    Fochsen Grethe

    2010-07-01

    Full Text Available Abstract Background During the past three decades, Oman has made significant progress in controlling TB within it's borders. However, the national TB control program elimination target has yet to be reached. This study aims to explore the perceived roles played by the immigrant population and the private health sector in relation to TB control in Oman. Methods We conducted seventeen interviews with different health care providers. The verbatim transcripts were processed using content analysis. Results Three main themes emerged. Firstly the threat of repatriation faced by underprivileged expatriates, secondly the criticized and forgotten private health sector as a key player and thirdly the user and provider barriers faced by Omani patients in the Omani public health system. Conclusions The study has identified some of the challenges and barriers to TB control in Oman. These challenges are mainly related to unintended negative consequences arising from the current repatriation policy of immigrants and to and the lack of involvement of the private sector in TB control. TB control strategies designed to address these challenges are needed, for Oman to reach its TB elimination targets.

  19. Obtaining strong ferromagnetism in diluted Gd-doped ZnO thin films through controlled Gd-defect complexes

    KAUST Repository

    Roqan, Iman S.

    2015-02-21

    We demonstrate the fabrication of reproducible long-range ferromagnetism (FM) in highly crystalline GdxZn1-xO thin films by controlling the defects. Films are grown on lattice-matched substrates by pulsed laser deposition at low oxygen pressures (≤25 mTorr) and low Gd concentrations (x ≤ 0.009). These films feature strong FM (10 μB per Gd atom) at room temperature. While films deposited at higher oxygen pressure do not exhibit FM, FM is recovered by post-annealing these films under vacuum. These findings reveal the contribution of oxygen deficiency defects to the long-range FM. We demonstrate the possible FM mechanisms, which are confirmed by density functional theory study, and show that Gd dopants are essential for establishing FM that is induced by intrinsic defects in these films.

  20. TB tracer teams in South Africa: knowledge, practices and challenges of tracing TB patients to improve adherence.

    Science.gov (United States)

    Bristow, Claire C; Podewils, Laura Jean; Bronner, Liza Ellen; Bantubani, Nonkqubela; Walt, Martie van der; Peters, Annatjie; Mametja, David

    2013-09-04

    In 2008-2009 the South African National Tuberculosis (TB) Program (NTP) implemented a national pilot project, the TB Tracer Project, aiming to decrease default rates and improve patient outcomes. The current study aimed to inform the NTP by describing the knowledge, attitudes, and practices of TB program personnel involved with tracing activities. A self-administered written questionnaire was sent to TB staff, managers and tracer team leaders to assess basic TB knowledge, attitudes and practices. Descriptive statistics were used to summarize results and the chi-squared statistic was used to compare responses of staff at facilities that participated in the TB Tracer Project (tracer) and those that followed standard NTP care (non-tracer). Of 560 total questionnaires distributed, 270 were completed and returned (response rate 48%). Total TB knowledge ranged from 70.8-86.3% correct across all response groups. However, just over half (range 50-59.3%) of each respondent group was able to correctly identify the four components of a DOT encounter. A patient no longer feeling sick was cited by 72.1% of respondents as the reason patients fail to adhere to treatment. Tracer teams were viewed as an effective means to get patients to return to treatment by 96.3% of health facility level respondents. Tracer team leaders reported concerns including lack of logistical support (41.7%), insufficient physical safety precautions (41.7%), and inadequate protection from contracting TB (39.1%). Upon patients returning to treatment at the clinic, facilities included in the TB Tracer Project were significantly more likely to discuss alternate DOTS arrangements than non-tracer facilities (79.2 vs. 66.4%, p = 0.03). This study identified key components of knowledge, attitudes, and practices regarding TB patient tracing activities in South Africa. Educating patients on the essential need to complete treatment irrespective of clinical symptoms may help improve treatment adherence. Future