Gd3(SeO3)4F: Ein Fluoridselenit mit μ3‐SeO32–und μ3‐F–‐überkappten Gd3‐Ringen

Gd₃(SeO₃)₄F: A Fluoride Selenite with μ₃‐SeO₃^2– and μ₃‐F^– Capped Gd₃ Rings The decomposition of Gd₂(SeO₄)₃ in the presence of LiF in sealed gold ampoules yields single crystals of Gd₃(SeO₃)₄F (hexagonal, P6₃mc, Z = 2, a = 1044.3(1), b = 694.32(7) pm, R_all = 0.0286). In the crystal structure one SeO₃^2– group and one F^– ion cap a ring of three Gd atoms. Furthermore, the crystal structure is strongly influenced by the lone pairs of the SeO₃^2– ions.     

Synthesis and crystal structure of d–f heteronuclear Gd(III)–Co(II) system

A carboxylate-bridged Co(II)–Gd(III) complex, [(bipy)CoL₃Gd(NO₃)L₃Co(bipy)] (HL =?α-methylacrylic acid, bipy =?2,2′-bipyridine), was prepared and characterized. Single crystal X-ray analysis reveals that the complex assumes a carboxylate-bridged CoGdCo unit. Magnetic measurements showed χ_m T decreases when the temperature is lowered.     

Structural comparison of gadolinium and lanthanum silicate films on Si(1 0 0) by HRTEM, EELS and SAED

High-resolution transmission electron microscopy (HRTEM), electron energy loss spectroscopy (EELS) and selected area electron diffraction (SAED) were used to study gadolinium and lanthanum silicate films deposited on Si(1 0 0) substrates using electron-beam evaporation from pressed-powder targets. As-deposited films consist of an amorphous silicate layer without an interfacial layer. After annealing at 900 °C in oxygen for 2 min, an interfacial SiO₂ layer is formed in the gadolinium silicate film, while this interfacial layer is a SiO₂-rich lanthanum silicate layer in the lanthanum silicate film. The formation of interfacial silicate layers is thermodynamically more favorable for the lanthanum films than for the gadolinium films. The gadolinium silicate films crystallize at a temperature between 1000 and 1050 °C, while the crystallization temperature for the lanthanum silicate films is between 900 and 950 °C.     

Hydrothermal synthesis and magnetic properties of gadolinium-doped CoFe2O4 nanoparticles

CoFe_2−xGd_xO₄ (x=0-0.25) nanoparticles were synthesized via a simple hydrothermal process at 200 °C for 16 h without the assistance of surfactant. The as-synthesized powders were characterized by X-ray diffraction, transmission electron microscopy, and a vibrating sample magnetometer. The X-ray diffraction results showed that the as-synthesized powders were in the pure phase with a doping amount of ≤0.25, and the peaks could be readily indexed to the cubic spinel cobalt ferrite. Transmission electron microscopy and high resolution transmission electron microscopy observations revealed that the gadolinium-doped cobalt ferrite nanoparticles were single crystal, roughly spherical, uniformly distributed, and not highly agglomerated. The room temperature magnetic field versus magnetization measurements confirmed a strong influence of gadolinium doping on the saturation magnetization and coercivity due to large lattice distortion and grain growth of small particles.     

DTPA双芳酰胺钆配合物作为肝胆磁共振成象造影剂

对三种DTPA双芳酰胺钆配合物用作肝胆磁共振成象造影剂进行了研究.配合物的亲脂性通过正辛醇-水分配比进行表征,结果表明实验值与理论值有很好的线性关系.蛋白结合实验表明亲脂性较强的配合物具有较强的蛋白结合能力.家兔的活体磁共振成象表明,将芳香环引入配合物中可以实现肝细胞对配合物的特异性摄取.     

A method for the making and utility of gadolinium-labeled albumin microbubbles

Objective

Perfluorocarbon-exposed sonicated dextrose albumin microbubbles (PESDA) binds scavenger receptors and can be noninvasively imaged. To enhance imaging, gadolinium (Gd)-labeled PESDA was developed and tested in a model of vascular inflammation by magnetic resonance imaging (MRI).

Methods and Results

Purified human serum albumin (HSA) (5%) was labeled with Gd via the covalent binding of diethylenetriaminepentacetic acid. Abdominal aortic tissues in Sprague-Dawley rats (n=5 per group) were analyzed by 7-T MRI and scanning electron microscopy to evaluate PESDA binding. Labeling-purified 5% human albumin resulted in an average of 16.1 Gd atoms per albumin molecule as determined by atomic absorption. Forty-eight hours after balloon angioplasty, aortic tissue was enhanced with Gd-PESDA as compared to control tissue. 7-T MRI of explanted tissues was sensitive to the detection of retained PESDA. Enhancement of aortic tissue in vivo was present albeit to a lesser extent than explanted tissue from the same animals.

Conclusions

HSA was successfully labeled, and an albumin-based microbubble with Gd was synthesized. This contrast agent, Gd-PESDA, may serve as an additional agent for the MRI evaluation of innate inflammation and used to noninvasively image early vascular pathophysiologic processes.

Condensed Abstract

In this study, Gd-PESDA microbubbles and were synthesized and shown to detect the binding of these microbubbles using MRI in injured aortic tissue. The method for synthesizing Gd-PESDA is detailed, and the proposed utility of this new contrast agent is discussed.     

Effects of charge storage dielectric thickness on hybrid gadolinium oxide nanocrystal and charge trapping nonvolatile memory

The characteristics of hybrid gadolinium oxide nanocrystal (Gd₂O₃-NC) and gadolinium oxide charge trapping (Gd₂O₃-CT) memories were investigated with different Gd₂O₃ film thickness. By performing the rapid thermal annealing on Gd₂O₃ films with different thickness, the Gd₂O₃-NCs with the diameter of 6–9 nm for charge storage, surrounded by the amorphous Gd₂O₃ (α-Gd₂O₃) layer, were formed. The α-Gd₂O₃ layer was considered to be the charge trapping layer, resulting in the large memory window of Gd₂O₃-NC/CT memories with thick Gd₂O₃ film. The charge trapping energy level of the Gd₂O₃-NCs and α-Gd₂O₃ layer was extracted to be 0.16 and 0.45 eV respectively by using the temperature-dependent retention measurement. Further, after a 10⁶ program/erase cycling operation, the memory with thin Gd₂O₃ film can be predicted to sustain a 94% memory window of the first cycling one while the memory with thick Gd₂O₃ film suffered from a 30% charge loss because of the traps within the α-Gd₂O₃ layer. The Gd₂O₃ film thickness of 10 nm was optimized to exhibit superior performances of the Gd₂O₃-NC/CT memory, which can be applied into the nonvolatile memory.