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Tb[sup 3+]-doped Lu[sub 2]O[sub 3] sintered ceramics were prepared in vacuum and in air. It was shown that the vacuum-sintered disks are able to store energy when irradiated with 300-nm or shorter photons. A small part of the stored energy could be recovered with 980-nm light. A much more significant amount of the stored energy could be released with red 647-nm photons. However, recovering the total stored energy could be accomplished only upon heating up to about 300 °C. Changes in absorption of the raw materials upon ultraviolet irradiation and subsequent IR (980 and 647 nm) treatments or upon heating at 300 °C are presented and discussed. A model for energy storing and recovering through the various IR irradiations or through heating is presented. At least two distinct ways of hole trapping as Tb[sup 4+] or V[sub k]-center as well as creation off and F[sup +] is suggested. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this report is to assess the safety of endovascular treatment for chronic cerebrospinal venous insufficiency (CCSVI). Although balloon angioplasty and stenting seem to be safe procedures, there are currently no data on the treatment of a large group of patients with this vascular pathology. Methods: A total of 564 endovascular procedures (balloon angioplasty or, if this procedure failed, stenting) were performed during 344 interventions in 331 CCSVI patients with associated multiple sclerosis. Results: Balloon angioplasty alone was performed in 192 cases (55.8%), whereas the stenting of at least one vein was required in the remaining 152 cases (44.2%). There were no major complications (severe bleeding, venous thrombosis, stent migration or injury to the nerves) related to the procedure, except for thrombotic occlusion of the stent in two cases (1.2% of stenting procedures) and surgical opening of femoral vein to remove angioplastic balloon in one case (0.3% of procedures). Minor complications included occasional technical problems (2.4% of procedures): difficulty removing the angioplastic balloon or problems with proper placement of stent, and other medical events (2.1% of procedures): local bleeding from the groin, minor gastrointestinal bleeding or cardiac arrhythmia. Conclusions: The procedures appeared to be safe and well tolerated by the patients, regardless of the actual impact of the endovascular treatments for venous pathology on the clinical course of multiple sclerosis, which warrants long-term follow-up. [ABSTRACT FROM AUTHOR]

Decay kinetics and X-ray diffraction patterns of Lu 2 O 3 :Eu with concentration of the dopant spanning 0-20% were measured for two series of materials with crystallites sized of 13 nm and 35 nm. For the series of smaller crystallites a very significant concentration quenching was observed, while for the larger crystallites the effect was minor only. Detailed structural analysis made it possible to postulate that this effect is related to an inhomogeneous distribution of Eu 3+ ions within the smaller crystallites. [ABSTRACT FROM AUTHOR]