| 1. |
- Meech, K. J., et al.
(författare)
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EPOXI: Comet 103P/Hartley 2 Observations from a Worldwide Campaign
- 2011
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Ingår i: Astrophysical Journal Letters. - London : IOP. - 2041-8213 .- 2041-8205. ; 734:L1, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- Earth- and space-based observations provide synergistic information for space mission encounters by providing data over longer timescales, at different wavelengths and using techniques that are impossible with an in situ flyby. We report here such observations in support of the EPOXI spacecraft flyby of comet 103P/Hartley 2. The nucleus is small and dark, and exhibited a very rapidly changing rotation period. Prior to the onset of activity, the period was ~16.4?hr. Starting in 2010 August the period changed from 16.6?hr to near 19?hr in December. With respect to dust composition, most volatiles and carbon and nitrogen isotope ratios, the comet is similar to other Jupiter-family comets. What is unusual is the dominance of CO 2 -driven activity near perihelion, which likely persists out to aphelion. Near perihelion the comet nucleus was surrounded by a large halo of water-ice grains that contributed significantly to the total water production.
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| 2. |
- Meijer, A., et al.
(författare)
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Adjusted prognostic association of depression following myocardial infarction with mortality and cardiovascular events: individual patient data meta-analysis
- 2013
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Ingår i: British Journal of Psychiatry. - : Royal College of Psychiatrists. - 0007-1250 .- 1472-1465. ; 203:2, s. 90-102
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Tidskriftsartikel (refereegranskat)abstract
- Background The association between depression after myocardial infarction and increased risk of mortality and cardiac morbidity may be due to cardiac disease severity. To combine original data from studies on the association between post-infarction depression and prognosis into one database, and to investigate to what extent such depression predicts prognosis independently of disease severity. An individual patient data meta-analysis of studies was conducted using multilevel, multivariable Cox regression analyses. Sixteen studies participated, creating a database of 10 175 post-infarction cases. Hazard ratios for post-infarction depression were 1.32 (95% CI 1.26-1.38, P<0.001) for all-cause mortality and 1.19 (95% CI 1.14-1.24, P<0.001) for cardiovascular events. Hazard ratios adjusted for disease severity were attenuated by 28% and 25% respectively. The association between depression following myocardial infarction and prognosis is attenuated after adjustment for cardiac disease severity. Still, depression remains independently associated with prognosis, with a 22% increased risk of all-cause mortality and a 13% increased risk of cardiovascular events per standard deviation in depression z-score.
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| 3. |
- Nazemi, L., et al.
(författare)
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Depression, Prevalence and Some Risk Factors in Elderly Nursing Homes in Tehran, Iran
- 2013
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Ingår i: Iranian Journal of Public Health. - 2251-6085. ; 42:6, s. 559-569
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Tidskriftsartikel (refereegranskat)abstract
- Background: The most common geriatric psychiatric disorder is depression, known to be a multi factorial disorder. However, the influence of common preventable factors is yet to be discovered. This study was designed to evaluate the prevalence of depression and some possible risk factors in elderly residents of nursing homes in Iran. Methods: Data on demographic characteristics, nutritional and health status of 244 residents aged 60 years or older were collected from seventeen nursing homes in Tehran, Iran, during 2010 to 2012. Depression was assessed and classified according to the 15-item GDS. Univariate and then multivariate complex sample survey ordinal regression analysis was performed to investigate the association between depression and the risk factors. Results: The average age of the 244 cases studied was 75.8 (+/- 8.7) years, 53.3% were female (of whom 74.2% were housewives), 43.4% illiterate, and 32.0% were divorced or were living separately. The percentages of non-depressed, mild, moderate and severe depression were 9.8%, 50.0%, 29.5% and 10.7%, respectively. Multivariate analysis showed that dissatisfaction with personnel of nursing homes and food quality had odds ratios of 2.91 (1.33-6.36) and 2.64 (1.44-4.87), corresponding to greater odds of having a higher grade depression. Moreover, those who rested or walked had significantly higher risk of a more severe depression in comparison with those who did not (OR of 2.25 (1.50-3.38) and 1.98 (1.24-3.18), respectively), however, studying had a protective odds ratio of 0.17 (0.13-0.22). Conclusion: Depression was very common in our sample and their lifestyle influenced its prevalence.
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| 4. |
- Ramon-Azcon, J., et al.
(författare)
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Gelatin methacrylate as a promising hydrogel for 3D microscale organization and proliferation of dielectrophoretically patterned cells
- 2012
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Ingår i: Lab on a Chip - Miniaturisation for Chemistry and Biology. - : Royal Society of Chemistry (RSC). - 1473-0189 .- 1473-0197. ; 12:16, s. 2959-2969
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Tidskriftsartikel (refereegranskat)abstract
- Establishing the 3D microscale organization of cells has numerous practical applications, such as in determining cell fate (e. g., proliferation, migration, differentiation, and apoptosis) and in making functional tissue constructs. One approach to spatially pattern cells is by dielectrophoresis (DEP). DEP has characteristics that are important for cell manipulation, such as high accuracy, speed, scalability, and the ability to handle both adherent and non-adherent cells. However, widespread application of this method is largely restricted because there is a limited number of suitable hydrogels for cell encapsulation. To date, polyethylene glycol-diacrylate (PEG-DA) and agarose have been used extensively for dielectric patterning of cells. In this study, we propose gelatin methacrylate (GelMA) as a promising hydrogel for use in cell dielectropatterning because of its biocompatibility and low viscosity. Compared to PEG hydrogels, GelMA hydrogels showed superior performance when making cell patterns for myoblast (C2C12) and endothelial (HUVEC) cells as well as in maintaining cell viability and growth. We also developed a simple and robust protocol for co-culture of these cells. Combined application of the GelMA hydrogels and the DEP technique is suitable for creating highly complex microscale tissues with important applications in fundamental cell biology and regenerative medicine in a rapid, accurate, and scalable manner.
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| 5. |
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| 6. |
- Baudoin, Eric, et al.
(författare)
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Effect of partial premixing on stabilization and local extinction of turbulent methane/air flames
- 2013
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Ingår i: Flow, Turbulence and Combustion. - : Springer Science and Business Media LLC. - 1573-1987 .- 1386-6184. ; 90:2, s. 269-284
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Tidskriftsartikel (refereegranskat)abstract
- Abstract in UndeterminedThe stabilization characteristics and local extinction structures of partially premixed methane/air flames were studied using simultaneous OH-PLIF/PIV techniques, and large eddy simulations employing a two-scalar flamelet model. Partial premixing was made in a mixing chamber comprised of two concentric tubes, where the degree of partial premixing of fuel and air was controlled by varying the mixing length of the chamber. At the exit of the mixing chamber a cone was mounted to stabilize the flames at high turbulence intensities. The stability regime of flames was determined for different degree of partial premixing and Reynolds numbers. It was found that in general partially premixed flames at low Reynolds numbers become more stable when the level of partial premixing of air to the fuel stream decreases. At high Reynolds numbers, for the presently studied burner configuration there is an optimal partial premixing level of air to the fuel stream at which the flame is most stable. OH-PLIF images revealed that for the stable flames not very close to the blowout regime, significant local extinction holes appear already. By increasing premixing air to fuel stream successively, local extinction holes grow in size leading to eventual flame blowout. Local flame extinction was found to frequently attain to locations where locally high velocity flows impinging to the flame. The local flame extinction poses a future challenge for model simulations and the present flames provide a possible test case for such study.
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| 7. |
- Hosseini-Hashemi, S., et al.
(författare)
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On the exact in-plane and out-of-plane free vibration analysis of thick functionally graded rectangular plates: Explicit 3-D elasticity solutions
- 2013
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Ingår i: Composites Part B: Engineering. - : Elsevier BV. - 1359-8368 .- 1879-1069. ; 46, s. 108-115
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Tidskriftsartikel (refereegranskat)abstract
- In this paper exact closed-form solutions of 3-D elasticity theory are presented to study both in-plane and out-of-plane free vibrations for thick functionally graded simply supported rectangular plates. The solution procedure of the transverse vibration utilizes Levinson's representation form to describe the displacement; in this way, the 3-D elasto-dynamic equations are written in terms of some suitable independent functions satisfying ordinary differential equations. A similar procedure is presented for in-plane vibration by introducing an appropriate displacement field. In each case, the obtained ordinary differential equations are analytically solved and boundary conditions are satisfied. The proposed solutions are validated by comparing some of the present results with corresponding results known in the literature as well as with 3-D Finite Element Method. Finally, the influence of inhomogeneity on the natural frequencies for a thick functionally graded rectangular plate is discussed.
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| 8. |
- Sburlati, R., et al.
(författare)
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Study on the effect of functionally graded coating layers on elastic deformation of thick circular plates: A closed-form elasticity solution
- 2013
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Ingår i: Composite Structures. - : Elsevier BV. - 0263-8223 .- 1879-1085. ; 99, s. 131-140
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, a closed-form solution is presented for displacements and stresses in a thick homogeneous circular plate coated by functionally grade (FG) layers subjected to transverse loading. The solution procedure is in the framework of infinitesimal theory of elasticity. The elasticity modulus of the FG coating layers is assumed to vary exponentially through the thickness, whereas Poisson's ratio remains constant. The solution procedure is on the basis of a Plevako's representation, which reformulates the elasticity equations into some uncoupled fourth-order partial differential equations with respect to some potential functions. We explicitly obtain the analytical solution by writing the potential functions as Fourier-Bessel series expansions with respect to the radial coordinate. The solution is validated by comparing the numerical results with their counterparts reported in literature for the conventional system of thick plates coated by homogeneous layers, as well as the 3-D finite element analysis. A comparative study is presented between a thick circular plate coated by functionally graded layers and the one with homogeneous coating layers.
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