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The use of LaNi5intermetallic for hydrogen storage is drastically limited due to its degradation during cycling. Despite extensive efforts in the literature to address this issue, a fundamental challenge remains - no one has been able to pinpoint the exact origin of this degradation. In this work, we elucidate the fundamental mechanisms behind this degradation using DFT calculations, a feat that couldn't be achieved through experimental methods alone. Particularly, our findings underscore the stability of the (2b) site in comparison to (6c1) and (6c2) sites. Hydrogen migration in the (x,y)-plane from (6c1)-site to (2b)-site is confirmed to be fast within the crystal structure, owing to a low barrier of 0.24 eV, which is much lower than that of MgH2. On the other hand, hydrogen diffusion from the (2b)-site to the (6c1)-site exhibits the highest energy barrier of 0.45 eV. These results emphasize the stability of the (2b)-site and provide a fundamental explanation for the degradation of LaNi5. Indeed, the occupation of the (2b)-site serves as the primary driving force behind the formation of stable hydrides that cannot be desorbed under ambient conditions.

The role of informatics in radiotherapy planning concerns dose calculation, dose distribution and quality assurance. Software research has recently developed to obtain 3-dimensional planning of treated volume and to reach more homogeneous dose distribution within radiation target volume. To increase therapeutic effectiveness, lower local relapses and reduce treatment sequelae, several quality assurance systems are being used, such as portal image analysis which allows an immediate comparison with the simulation film. Such procedures are carried out through informatics and need state-of-the-art computed systems, dedicated radiological devices and highly qualified teams as well.

Drug plasma levels, metabolism data and clinical results were evaluated after the daily administration of either 500 or 1,000 mg aminoglutethimide (AG, Orimeten, Ciba-Geigy) plus hydrocortisone acetate (20 mg b. i. d.). A total of 34 patients with advanced breast cancer entered the study: 17 were given 1,000 mg/day and 17 received 500 mg/day for at least 3 months. A novel HPLC method was developed to determine the levels of AG and its known metabolites [N-acetyl-AG (NAG), formyl-AG, nitroglutethimide, hydroxy-AG] in the biological samples. AG plasma concentration was significantly higher during the 1,000-mg/day regimen. NAG was the only metabolite observed in plasma, always occurring at concentrations lower than those of the parent drug. The ratios between NAG and AG levels distinguish two statistically different groups of patients. Irrespective of the dose, a partial response was observed in 44% of the patients; no change in 32% of cases; and progressive disease had an incidence of 24%. The probability of response was not dependent on the drug AUC or on the NAG/AG ratio and did not significantly depend on previous hormone treatment. Neither the plasmatic level of the AG or metabolite concentrations nor the NAG/AG ratio seemed to affect the incidence of side effects.

In this paper we report on the structural, magnetic and transport properties of La0.7(CaSr)0.3Mn1[?]xGaxO3 (x = 0, 0.025, 0.05, 0.075 and 0.1) manganites elaborated by sol-gel method. The substitution of Mn by Ga affects slightly the structural parameters. A decrease of both magnetization M and Curie temperature Tc has been observed with increasing Ga content. The temperature dependence of the resistance shows a metal-insulator transition around TC.