Harm avoidance and depression, anxiety, insomnia, and migraine in fifth-year medical students in Taiwan.

PURPOSE: During medical school training, increased stress, depression, and anxiety are common. Certain personality traits, particularly harm avoidance (HA), may increase the risk of psycho-pathological disorders, insomnia, and migraine among medical students. This study evaluated the role HA may play on levels of stress, depression, anxiety, and insomnia among Taiwanese medical students starting their fifth and final year of medical school. PATIENTS AND METHODS: A series of self-report questionnaires were used to measure the severity of anxiety, depression, and insomnia, as well as somatic symptoms, particularly migraine headache, among 143 Taiwanese fifth-year medical students (94 males and 49 females). Most had normal or mild levels of anxiety, depression, insomnia, and migraine. RESULTS: HA personality trait was significantly associated with depression (all P ≤ 0.001) after adjusting for other factors. HA was not significantly associated with anxiety, insomnia, or migraine headache days. CONCLUSION: HA personality trait was significantly associated with depression among fifth-year medical students in Taiwan.

Effect of Focused Ion Beam Imaging on the Crystallinity of InAs.

We investigated the effect of focused ion beam (FIB) imaging on the crystallinity of InAs using Raman scattering. A spatial correlation model was used to fit the broad band induced by FIB imaging. The fitting gives a correlation length of ~42 Å for the noisiest image condition (with an ion fluence of 7.4×1010 cm-2), implying severe damage in the surface layer of InAs. However, further increasing the fluence by several orders of magnitude only decreases the correlation length from 42 to 35 Å. We attribute the severe damage to the high beam current density and the low scanning speed of the FIB imaging process. These process conditions, along with low InAs thermal conductivity, also leads to a high local temperature in the exposed region that largely annihilated the defects and resulted in the nearly fluence-independent behavior.

Energy band structure tailoring of vertically aligned InAs/GaAsSb quantum dot structure for intermediate-band solar cell application by thermal annealing process.

This study presents an band-alignment tailoring of a vertically aligned InAs/GaAs(Sb) quantum dot (QD) structure and the extension of the carrier lifetime therein by rapid thermal annealing (RTA). Arrhenius analysis indicates a larger activation energy and thermal stability that results from the suppression of In-Ga intermixing and preservation of the QD heterostructure in an annealed vertically aligned InAs/GaAsSb QD structure. Power-dependent and time-resolved photoluminescence were utilized to demonstrate the extended carrier lifetime from 4.7 to 9.4 ns and elucidate the mechanisms of the antimony aggregation resulting in a band-alignment tailoring from straddling to staggered gap after the RTA process. The significant extension in the carrier lifetime of the columnar InAs/GaAsSb dot structure make the great potential in improving QD intermediate-band solar cell application.