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431.
Alexander Gribanov Andriy Grytsiv Peter Rogl Gerald Giester 《Journal of solid state chemistry》2008,181(11):2964-2975
Phase relations in the ternary system Ce-Pt-Si have been established for the isothermal section at 800 °C based on X-ray powder diffraction, metallography, scanning electron microscopy (SEM) and electron probe microanalysis (EPMA) techniques on about 120 alloys, which were prepared by various methods employing arc-melting under argon or powder reaction sintering. Nineteen ternary compounds were observed. Atom order in the crystal structures of τ18-Ce5(Pt,Si)4 (Pnma; a=0.77223(3) nm, b=1.53279(8) nm c=0.80054(5) nm), τ3-Ce2Pt7Si4 (Pnma; a=1.96335(8) nm, b=0.40361(4) nm, c=1.12240(6) nm) and τ10-CePtSi2 (Cmcm; a=0.42943(2) nm, b=1.67357(5) nm, c=0.42372(2) nm) was determined by direct methods from X-ray single-crystal CCD data and found to be isotypic with the Sm5Ge4-type, the Ce2Pt7Ge4-type and the CeNiSi2-type, respectively. Rietveld refinements established the atom arrangement in the structures of Pt3Si (Pt3Ge-type, C2/m, a=0.7724(2) nm, b=0.7767(2) nm, c=0.5390(2) nm, β=133.86(2)°), τ16-Ce3Pt5Si (Ce3Pd5Si-type, Imma, a=0.74025(8) nm, b=1.2951(2) nm, c=0.7508(1) nm) and τ17-Ce3PtSi3 (Ba3Al2Ge2-type, Immm, a=0.41065(5) nm, b=0.43221(5) nm, c=1.8375(3) nm). Phase equilibria in Ce-Pt-Si are characterised by the absence of cerium solubility in platinum silicides. Cerium silicides and cerium platinides, however, dissolve significant amounts of the third component, whereby random substitution of the almost equally sized atom species platinum and silicon is reflected in extended homogeneous regions at constant Ce content such as for τ13-Ce(PtxSi1−x)2, τ6-Ce2Pt3+xSi5−x or τ7-CePt2−xSi2+x. 相似文献
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Perihan ünak F. Zümrüt Biber Müftüler ?i?dem ??hedef E. ?lker Medine Kübra ?zmen Turan ünak Ayfer Yurt Kil?ar F. Gül Gümü?er Yasemin Parlak Elvan Say?t Bilgin 《Journal of Radioanalytical and Nuclear Chemistry》2012,293(1):57-66
Diethylstilbestrol (DES) is a well known, nonsteroidal estrogen with high affinity for the estrogen receptor (ER). Today DES is used to treat breast and prostate cancers. A phosphate derivative of DES [Diethylstilbestrol diphosphate (DES-P)] which is specific to tumor cells consisting alkaline phosphatase enzyme was synthesized and labeled with 99mTc using tin chloride as reducing agent. In vivo biological activity of 99mTc labeled diethylstilbestrol phosphate compound (99mTc-DES-P) was examined by biodistribution studies on Wistar Albino rats. Statistical evaluation was performed using SPSS 13 program. The percentage (%) radiolabeling yield of 99mTc-DES-P and quality control studies were done by Thin Layer Radio Chromatography (TLRC). Results showed that, 99mTc-DES-P may be proposed as an imaging agent for ER enriched tumors such as uterus and prostate and their metastases in bones. 相似文献
435.
Say Song Goh Zhi Yuan Lim Zuowei Shen 《Applied and Computational Harmonic Analysis》2006,20(3):411-421
For a given set of wavelets Ψ, we provide a general, and yet simple, method to derive a new set of wavelets such that each wavelet in is either symmetric or antisymmetric. The affine system generated by is a tight frame for the space whenever the affine system generated by Ψ is so. Further, when Ψ is constructed via a multiresolution analysis, can also be derived from a, but possibly different, multiresolution analysis. If moreover the multiresolution analysis for constructing Ψ is generated by a symmetric refinable function, then is obtained from the same multiresolution analysis. 相似文献
436.
Andriy V. Tkachuk 《Journal of solid state chemistry》2006,179(5):1506-1512
The ternary rare-earth cadmium antimonides RECd1−xSb2 (RE=La, Ce, Pr, Nd, Sm) were prepared by reaction of the elements at 1000 °C. The presence of Cd defects, previously found for LaCd0.700(5)Sb2 and CeCd0.660(4)Sb2, has been confirmed by single-crystal X-ray diffraction studies for the isotypic compounds PrCd0.665(3)Sb2, ), NdCd0.659(3)Sb2, ), and SmCd0.648(3)Sb2, ). These compounds adopt the HfCuSi2-type structure (Pearson symbol tP8, space group P4/nmm, Z=2). The electrical and magnetic properties of samples with nominal composition RECd0.7Sb2 were investigated. All exhibit metallic behaviour, but CeCd0.7Sb2 undergoes an abrupt drop in its electrical resistivity below 3 K. LaCd0.7Sb2 exhibits temperature-independent Pauli paramagnetism and SmCd0.7Sb2 displays van Vleck paramagnetism. The remaining compounds obey the modified Curie-Weiss law at high temperatures. CeCd0.7Sb2 undergoes ferromagnetic ordering below 3 K, reaching a saturation magnetization of ∼1.0 μB, whereas PrCd0.7Sb2 and NdCd0.7Sb2 remain paramagnetic down to 2 K. 相似文献
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Imai T Isogai H Seto T Kovalenko A Hirata F 《The journal of physical chemistry. B》2006,110(24):12149-12154
The change in partial molar volume (PMV) accompanying the xenon-lysozyme binding was investigated for elucidating the molecular mechanism of the pressure reversal of general anesthesia, using the three-dimensional reference interaction site model theory of molecular solvation. An increase of the PMV from xenon binding to the substrate binding site of lysozyme was found, and the binding is suppressed by pressure, while the internal site binding did not change the PMV. The PMV change was analyzed by decomposing it into several contributions from geometry and hydration. We also analyzed the hydration change due to the binding. From the results, we draw a molecular picture of the PMV change accompanying xenon-lysozyme binding, which gives a possible mechanism of pressure reversal of anesthesia. 相似文献
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Fiona M. Fennessy Andriy Fedorov Sandeep N. Gupta Ehud J. Schmidt Clare M. Tempany Robert V. Mulkern 《Magnetic resonance imaging》2012
There are many challenges in developing robust imaging biomarkers that can be reliably applied in a clinical trial setting. In the case of dynamic contrast-enhanced (DCE) MRI, one such challenge is to obtain accurate precontrast T1 maps for subsequent use in two-compartment pharmacokinetic models commonly used to fit the MR enhancement time courses. In the prostate, a convenient and common approach for this task has been to use the same 3D spoiled gradient-echo sequence used to collect the DCE data, but with variable flip angles (VFAs) to collect data suitable for T1 mapping prior to contrast injection. However, inhomogeneous radiofrequency conditions within the prostate have been found to adversely affect the accuracy of this technique. Herein we demonstrate the sensitivity of DCE pharmacokinetic parameters to precontrast T1 values and examine methods to improve the accuracy of T1 mapping with flip angle-corrected VFA SPGR methods, comparing T1 maps from such methods with “gold standard” reference T1 maps generated with saturation recovery experiments performed with fast spin-echo (FSE) sequences. 相似文献