PurposeThe education of surgical trainees should be based on an accurate evaluation of their surgical skill levels. In our hospital, the Objective Structured Assessment of Technical Skills (OSATS) is used for this purpose. We conducted this study to demonstrate the validity and accuracy of the OSATS for assessing surgical skills in the operating room (OR) setting.MethodsBetween January, 2007 and December, 2010, the OSATS global rating scale was used to assess several operations in which surgical trainees participated. We assessed ten surgical trainees who participated as the main surgeon or first assistant, and studied the correlation between their postgraduate year and their OSATS score.ResultsThe median score of the global rating scale for each trainee improved with each year of experience. The median scores of all trainees in postgraduate years 3, 4, and 5 were significantly different (p < 0.001 for both the main surgeon and first assistant roles; Kruskal–Wallis test).ConclusionUsing the OSATS global rating scale to assess the surgical skills of trainees in the OR was feasible and effective.

As a novel scintillation material, the use of Ce-doped Gd 2 Si 2 O 7 was investigated. In fact, (Gd 0.9 Ce 0.1 ) 2 Si 2 O 7 powder showed about five-times greater light output than Gd 2 SiO 5 (GSO) powder samples for alpha-particles from 241 Am. Furthermore, a fast decay constant of 59 ns was obtained for alpha-particles from 241 Am. Relations between the Ce-concentration, crystal structure and luminescence characteristics were also elucidated. Results of these studies show that heavy Ce-doping alters the Gd 2 Si 2 O 7 crystal structure and that the luminescence intensity is dependent not on Ce-concentration but on the triclinic structure formed by heavy Ce-doping.

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The melting and solidification behavior of the (Gd0.9Ce0.1)2Si2O7 (Ce:GPS) which shows attractive scintillation performance was investigated by means of the slow cooling floating zone (SCFZ) method. Although Ce:GPS melts incongruently, the peritectic composition is estimated to be very close to the GPS composition, less than 67.0 mol % of SiO2 in the (Gd,Ce)2O3−SiO2 system. Constitutional supercooling occurred when approximately 70% volume of the melt was solidified, consequently, the lamellar structure consists of Ce:GPS and the amorphous phase was obtained. On the basis of our study, it is estimated that a volume of 70% of the starting material, whose composition is SiO2 = 67 mol % in the (Gd,Ce)2O3−SiO2 system at Ce 10 mol %, can be solidified as the GPS phase using top-seeded solution growth (TSSG) with the self-flux of SiO2.