6,928 research outputs found
Prophylactic oral antibiotics in prevention of recurrent cholangitis after the Kasai portoenterostomy.
No full text
Systematic and material independent variation of electrical, optical, and chemical properties of Ln-materials over the Ln-series (Ln=La,Ce,Pr,..,Lu)
No full textA model is presented that successfully predicts electro-optical properties of Lanthanide materials, irrespective whether these materials are inorganic or organic, diluted or concentrated, metallic, semi-conducting or insulating. The model is firmly based on recent experimental data revealing that the variation in 4f and 5d energies relative to the valence band over the Ln series (La, Ce, Pr,.. ,Lu) is universal. Application to LnS and the oxides LnO, Ln2O3 and LnO2 demonstrates its potential by correctly predicting the ground state electron configuration, metallic, insulating or semi-conducting behavior, Ln ion valence state and band-gap of these model Ln systems.Radiation, Radionuclides and ReactorsApplied Science
Lanthanide complexes of disulfoxide ligands with varied configurations: Influence of lanthanide contraction on the structures of the complexes
No full textFour new disulfoxide-Ln(III). complexes, [Ln(L)(2)(NO3)(3)](n) {Ln = La (1), n = n; Ln = Gd (2), Dy (3) and Yb (4), n = 2}, have been prepared by the reaction of Ln(NO3)(3)center dot nH(2)O with meso-1, 3-bis(ethylsulfinyl) propane (meso-L) in methanol/triethylorthoformate, and their solid-state structures were characterized by IR spectroscopy, elemental analyses and X-ray diffraction. Complex 1 is a 1D double-bridged chain in which the La-III ions are ten-coordinate and the L ligands adopt both meso and rac configurations, and a bis-monodentate bridging coordination mode. While complexes 2-4 have isostructural dinuclear structures, in which the Ln(III) ions are nine-coordinate and the ligands show two types of coordination fashions and configurations: bis-monodentate bridging with a meso-configuration, and monodentate coordination with a rac-configuration. The structural differences between 1 and 2-4 indicate the influence of lanthanide contraction on the complex structures. In addition, a change in configuration of the ligand occurs when it reacts with metal ions. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000229457900012&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Chemistry, Inorganic & NuclearSCI(E)6ARTICLE101913-191
Aspects of the social geography of the province of Sistan/Baluchestan, Iran
Full text linkThe Kordi (Kurd) tribe now living in Iranian Baluchestan would appear to be an offshoot of the far more numerous Kurdish peoples of the north-western Zagros Mountains of Iran-Iraq. The Kordi were settled in their present location possibly in the l6th Century AD, but much more likely in the l8th Century, originally to act as tax-gatherers on behalf of the Shah-in-Shah. For many years they lived as pastoralists (often nomadic), tax gatherers, guardians of the frontier, and by raiding and plunder. Their habitat, round the Kuh-e-Taftan massif (one of the more fertile areas in the extremely arid and topographically difficult region of Baluchestan) allows some agriculture; and since the 1940's especially, the Kordi people have turned increasingly to a settled way of life based on mixed farming - mostly cultivation, with some animal herding. The thesis examines the origins of the Kordi, their geographical environment, social organisation and demography; and considers present and future evolution of this people in a changed and changing Iranian State
Heteronuclear bipyrimidine-bridged Ru-Ln and Os-Ln dyads: low-energy 3MLCT states as energy-donors to Yb(III) and Nd(III).
No full textThe complexes [Ru((t)Bu(2)bipy)(bpym)X(2)] (X = Cl, NCS) and [M((t)Bu(2)bipy)(2)(bpym)][PF(6)](2) (M = Ru, Os) all have a low-energy LUMO arising from the presence of a 2,2'-bipyrimidine ligand, and consequently have lower-energy (1)MLCT and (3)MLCT states than analogous complexes of bipyridine. The vacant site of the bpym ligand provides a site at which [Ln(diketonate)(3)] units can bind to afford bipyrimidine-bridged dinuclear Ru-Ln and Os-Ln dyads; four such complexes have been structurally characterised. UV/Vis and luminescence spectroscopic studies show that binding of the Ln(III) fragment at the second site of the bpym ligand reduces the (3)MLCT energy of the Ru or Os fragment still further. The result is that in the dyads [Ru((t)Bu(2)bipy)X(2)(mu-bpym)Ln(diketonate)(3)] (X = Cl, NCS) and [Os((t)Bu(2)bipy)(2)(mu-bpym)Ln(diketonate)(3)][PF(6)](2) the (3)MLCT is too low to sensitise the luminescent f-f states of Nd(III) and Yb(III), but in [Ru((t)Bu(2)bipy)(2)(mu-bpym)Ln(diketonate)(3)][PF(6)](2) the (3)MLCT energy of 13,500 cm(-1) permits energy transfer to Yb(III) and Nd(III) resulting in sensitised near-infrared luminescence on the microsecond timescale
Copper Lanthanide Phosphonate Cages: Highly Symmetric {Cu(3)Ln(9)P(6)} and {Cu(6)Ln(6)P(6)} Clusters with C-3v and D-3h Symmetry
No full textPineda EM, Heesing C, Tuna F, et al. Copper Lanthanide Phosphonate Cages: Highly Symmetric {Cu(3)Ln(9)P(6)} and {Cu(6)Ln(6)P(6)} Clusters with C-3v and D-3h Symmetry. Inorganic Chemistry. 2015;54(13):6331-6337.Two families of copper lanthanide phosphonate clusters have been obtained through reaction of [Cu-2((O2CBu)-Bu-t)(4)((HO2CBu)-Bu-t)(2)] and either Ln(NO3)(3)center dot nH(2)O or [Ln(2)(O(2)C(t)nu)(6)((HO2CBu)-Bu-t)(6)} and tert-butylphosphonic acid or an amino-functionalized phosphonic acid. The clusters, with general formula [Cu(MeCN)(4)][Cu(3)Ln(9)(mu(3)-OH)(7)((O3PBu)-Bu-t)(6)((O2CBu)-Bu-t)(15)} and [Cu(6)Ln(6)(mu(3)-OH)(6)(O3PC(NH2)Me-2)(6)((O2CBu)-Bu-t)(12)}, were structurally characterized through single crystal X-ray diffraction and possess highly symmetric metal cores with approximately C-3v and D-3h point symmetry, respectively. We have investigated the possible application of the isotropic analogues in magnetic cooling, where we were able to observe that up to around 70% of the theoretical magnetic entropy change is obtained. Simulation of the magnetic data shows antiferromagnetic coupling between the spin centers, which explains the magnetic entropy value observed
High-temperature X-ray diffraction measurements of fluorite-related rare earth antimonates Ln(3)SbO(7) (Ln = Nd, Tb) and their magnetic properties
Full text linkTernary rare-earth antimonates Ln(3)SbO(7) (Ln=rare earths) were prepared, and their structures were determined by X-ray diffraction measurements. They crystallize in an orthorhombic superstructure of cubic fluorite (space group Cmcm for Ln=La, Pr; Ccmm for Ln=Sm-Dy), in which Ln(3+) ions occupy two different crystallographic sites (the 8-coordinated and 7-coordinated). For Ln=Nd, two phases with the Cmcm and Cam space groups coexist at room temperature. When the temperature was increased, the Nd3SbO7 compound transformed into a single phase with the space group Cmcm. Through magnetic susceptibility measurements, an antiferromagnetic transition was observed at 3.0 K (Ln=Nd) and 7.8 K (Ln=Tb). Analysis of the magnetic specific heat for Tb3SbO7 indicates that the 8-coordinated Tb ions magnetically orders at 7.8 K, and with furthermore decreasing temperature, the 7-coordinated Tb ions shows antiferromagnetic ordering at 3.0 K
Synthesis and magnetic properties of 12L-perovskites Ba4LnIr3O12 (Ln = lanthanides)
Full text linkNew quadruple perovskite oxides Ba4LnIr3O12 (Ln = lanthanides) were prepared and their magnetic properties were investigated. They crystallize in the monoclinic 12L-perovskite-type structure with space group C2/m. The Ir3O12 trimers and LnO6 octahedra are alternately linked by corner-sharing and form the perovskite-type structure with 12 layers. The Ln and Ir ions are both in the tetravalent state for Ln = Ce, Pr, and Tb compounds (Ba4Ln^[4+]Ir^[4+]3O12), and for other compounds (Ln = La, Nd, Sm-Gd, Dy-Lu), Ln ions are in the trivalent state and the mean oxidation state of Ir ions is +4.33(Ba4Ln^[3+]Ir^[4.33+]3O12). An antiferromagnetic transition has been observed for Ln = Ce, Pr, and Tb compounds at 10.5, 35, and 16 K, respectively, while the other compounds are paramagnetic down to 1.8 K
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