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The Zung Self-Rating Depression Scale (SDS) is generally used to screen for the presence of depression. The purpose of this study was to investigate scores on the SDS, Japanese version, in undergraduates at Tsurumi University School of Dental Medicine in Yokohama, Japan. A total of 2,197 dental students completed the SDS from 2006 through 2008. The investigation took place each year over a 3-week period from June to July. When investigating, the Institutional Review Board at Tsurumi University approved the study. Students could voluntarily agree or decline to participate in the study, and all responses were provided anonymously. SDS scores by sex, class year, and change over time were analyzed. The mean SDS score ranged from 43.7 ± 8.5 to 44.8 ± 9.0 between 2006 and 2008. Women were significantly more depressed than men in 2007 and 2008. The SDS scores of the same students were high continuously for 2 years. "Diurnal variation," "personal devaluation," and "confusion" had the highest scores of the 20 individual items of the SDS. Of the participating students, 31.4-37.2% were classified as being moderately to severely depressed. Logistic regression analysis was used to compute the odds ratio for SDS scores of ≤47 versus ≥48. The item "suicidal rumination" had the highest chance of being associated with depressive symptoms in all 3 years. Although this research was limited to a single department of dentistry, it appears that dental students experience various levels of depression. Providing mental healthcare options to these students may be helpful.

International audienceA purification procedure for single-wall carbon nanotubes prepared by the arc-discharge method is described that employs a new step of potassium intercalation. Thermogravimetric analysis, Raman spectroscopy, X-ray diffraction, and transmission electron microscopy were used to characterize the results of each purification step. This potassium intercalation step is particularly useful for exfoliating the graphitic shell structure that typically surrounds the metal catalyst particles that remain from the nanotube synthesis. By exfoliating the shell structure, subsequent treatments are more efficacious for removing the metal catalyst particles. By testing full purification procedures, it is demonstrated that with potassium intercalation the number of purification steps can be reduced

Purpose The aim of this research was to obtain an objective grasp of the surface properties of titanium castings which are polished using a titanium polishing method developed by our university. Methods The specimens were cast conventionally using commercially pure (CP) titanium (Grade 3, T-alloy H, GC). The cast surfaces were polished using two methods ; a conventional procedure for mirror surfaces and a modified procedure consisting of minimal grinding foracceptable fit of the inner surface. The center line average roughness (Ra) wasmeasured, and then qualitative analysis and map analysis were performed using Electron Probe X-ray Microanalysis. In addition, map and line analysis on sections of the as-cast titanium specimens was performed, and the Vickers hardness of the surface was measured. As controls, Au-Pt alloy and Co-Cr alloy specimens were analyzed. Results The Ra on the titanium inner surface was 1.52 ,um, which was approximately four times higher than that on the mirror surface, and approximately two times higher than that for the Au-Pt alloy and Co-Cr alloy. The qualitative analysis of the titanium mirror surface detected elements such as C, Si, and Al as well as the ingot element. In addition, P was also detected on the titanium inner surface. The Vickers hardness was highest on the outermost surface layer, which decreased remarkably until a depth of 100-150 gm. Conclusions It was considered that the mirror surface formed by the titanium polishing method in our university obtained a level equivalent to that of precious metals. However, a reaction layer and elements derived from the investment material remained in the titanium inner surface.

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