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- Bauer, M., et al.
(författare)
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Variations in seasonal solar insolation are associated with a history of suicide attempts in bipolar I disorder
- 2021
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Ingår i: International Journal of Bipolar Disorders. - : Springer Science and Business Media LLC. - 2194-7511. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Background Bipolar disorder is associated with circadian disruption and a high risk of suicidal behavior. In a previous exploratory study of patients with bipolar I disorder, we found that a history of suicide attempts was associated with differences between winter and summer levels of solar insolation. The purpose of this study was to confirm this finding using international data from 42% more collection sites and 25% more countries. Methods Data analyzed were from 71 prior and new collection sites in 40 countries at a wide range of latitudes. The analysis included 4876 patients with bipolar I disorder, 45% more data than previously analyzed. Of the patients, 1496 (30.7%) had a history of suicide attempt. Solar insolation data, the amount of the sun's electromagnetic energy striking the surface of the earth, was obtained for each onset location (479 locations in 64 countries). Results This analysis confirmed the results of the exploratory study with the same best model and slightly better statistical significance. There was a significant inverse association between a history of suicide attempts and the ratio of mean winter insolation to mean summer insolation (mean winter insolation/mean summer insolation). This ratio is largest near the equator which has little change in solar insolation over the year, and smallest near the poles where the winter insolation is very small compared to the summer insolation. Other variables in the model associated with an increased risk of suicide attempts were a history of alcohol or substance abuse, female gender, and younger birth cohort. The winter/summer insolation ratio was also replaced with the ratio of minimum mean monthly insolation to the maximum mean monthly insolation to accommodate insolation patterns in the tropics, and nearly identical results were found. All estimated coefficients were significant at p < 0.01. Conclusion A large change in solar insolation, both between winter and summer and between the minimum and maximum monthly values, may increase the risk of suicide attempts in bipolar I disorder. With frequent circadian rhythm dysfunction and suicidal behavior in bipolar disorder, greater understanding of the optimal roles of daylight and electric lighting in circadian entrainment is needed.
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| 2. |
- Villamayor, Michelle Marie S., et al.
(författare)
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Growth of two-dimensional WS2 thin films by reactive sputtering
- 2021
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Ingår i: Vacuum. - : Elsevier. - 0042-207X .- 1879-2715. ; 188
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Tidskriftsartikel (refereegranskat)abstract
- We have deposited WS2 thin films on Si, SiO2/Si, and sapphire substrates by reactive sputtering from a WS2 target in an Ar/H2S atmosphere. We demonstrate that it is possible to deposit (001)-textured tungsten sulfide films that are thicker than 100 nm. However, the sputtered films are slightly substoichiometric with a composition of WS1.94. Films were deposited at different processing pressures (0.67 Pa?6.67 Pa), substrate temperatures (up to 700 ?C) and relative amounts of H2S (0%?100%) in the gas mixture. Structure, morphology, composition, and resistivity of the films were investigated for the different processing conditions. Results from X-ray diffraction show that best crystallization was achieved for the highest substrate temperatures and processing pressures. We show that the addition of H2S may help obtaining fully stoichiometric films and reduce the risk of losing the (001) texture for thicker films. The challenges of obtaining an epitaxial and fully stoichiometric film are pointed out and suggestions on how to modify the process parameters in order to obtain films with even higher quality are presented.
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