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- Autio, Erkko, et al.
(författare)
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Entrepreneurial intent among students in Scandinavia and in the USA
- 2001
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Ingår i: Enterprise and Innovation Management Studies. - : Carfax Publishing. - 1463-2446. ; 2:2, s. 145-160
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Tidskriftsartikel (refereegranskat)abstract
- An application of the theory of planned behaviour is developed here to analyse factors in. uencing entrepreneurial intent among university students. The study provides a test of the robustness of the intent approach using international comparisons. The samples are from Finland (Helsinki University of Technology), Sweden (Linko¨ping University), USA (Stanford University and University of Colorado, Colorado Springs), and the UK (London Business School). The international comparisons indicate a good robustness of the model. Perceived behavioural control emerges as the most important determinant of entrepreneurial intent.
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| 3. |
- Gherman, Bogdan, George, et al.
(författare)
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LES of swirling flows in gas turbine combustion chambers
- 2004
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Ingår i: Proceedings of the ASME Turbo Expo 2004. ; 1, s. 465-473
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Konferensbidrag (refereegranskat)abstract
- The flow and mixing in a swirl-stabilized gas-turbine burner is studied by Large Eddy Simulations (LES). Each swirler has a different mass flux and swirl angle. The interaction between neighbouring jets is studied, co-rotating and counter rotating jets are considered. Another issue of importance is related to the jet inlet conditions (e.g. axial distribution and levels of turbulence). In addition to the flow field (using LES) we present results related to fuel/air mixing under different conditions. We show that the LES results can resolve several issues related to the burner that cannot be accounted for by the standard RANS computations.
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| 6. |
- Hua, Jianyi, et al.
(författare)
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Oxi4503, a novel vascular targeting agent: effects on blood flow and antitumor activity in comparison to combretastatin A-4 phosphate.
- 2003
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Ingår i: Anticancer research. - 1791-7530. ; 23:2B, s. 1433-1440
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Tidskriftsartikel (refereegranskat)abstract
- Oxi4503, which is the diphosphate prodrug of combretastatin A1, is a novel vascular targeting agent from the combretastatin family. Another member of this family, Combretastatin A-4 phosphate (CA4P), is a well-characterized vascular targeting agent already being evaluated in clinical trials. The potential for tumor vascular targeting by Oxi4503 was assessed in a mouse system. This approach aims to shut down the established tumor vasculature, leading to the development of extensive tumor cell necrosis. The vascular effects of Oxi4503 were assessed in the s.c. implanted MDA-MB-231 adenocarcinoma and the MHEC5-T hemangio-endothelioma in SCID mice and in a range of normal tissues. Blood flow was measured by i.v. injection of fluorescence beads, while quantitative fluorescence microscopy was used to measure the spatial heterogeneity of blood flow in tumor sections. Oxi4503 induced the shutdown of tumor blood vessels in a dose-dependent pattern with an ED50 at 3 mg/kg in contrast to 43 mg/kg of CA4P. Quantitative fluorescence microscopy showed that Oxi4503 increased the spatial heterogeneity in tumor blood flow. Oxi4503 affected peripheral tumor regions less than central regions, although this was not as pronounced as seen with CA4P, where only central regions were affected. The vascular shutdown induced by administration of Oxi4503 at a dose of 6 mg/kg resulted in extensive cell loss 24 hours following treatment, which translated into a significant effect on tumor growth. Tumor growth was completely repressed at doses above 12.5 mg/kg of Oxi4503, while doses above 25 mg/kg showed tumor regression and even complete regression in some animals. These results are promising for the use of Oxi4503 as a tumor vascular targeting agent. Moreover the potent antitumor effect when administered as a single agent suggests a different activity profile than CA4P.
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| 7. |
- Michael, Eli, et al.
(författare)
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Hubble Space Telescope Observations of High-Velocity Lyα and Hα Emission from Supernova Remnant 1987A : The Structure and Development of the Reverse Shock
- 2003
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 593, s. 809-830
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Tidskriftsartikel (refereegranskat)abstract
- We present two-dimensional line profiles of high-velocity (~+/-12,000 km s-1) Lyα and Hα emission from supernova remnant 1987A obtained with the Space Telescope Imaging Spectrograph between 1997 September and 2001 September (days 3869-5327 after the explosion). This emission comes from hydrogen in the debris that is excited and ionized as it passes through the remnant's reverse shock. We use these profiles to measure the geometry and development of the reverse-shock surface. The observed emission is confined within ~+/-30° about the remnant's equatorial plane. At the equator, the reverse shock has a radius of ~75% of the distance to the equatorial ring. We detect marginal differences (6%+/-3%) between the location of the reverse-shock front in the northeast and southwest parts of the remnant. The radius of the reverse shock surface increases for latitudes above the equator, a geometry consistent with a model in which the supernova debris expands into a bipolar nebula. Assuming that the outer supernova debris has a power-law density distribution, we can infer from the reverse-shock emission light curve an expansion rate (in the northeast part of the remnant) of 3700+/-900kms-1, consistent with the expansion velocities determined from observations in radio (Manchester et al.) and X-ray (Park et al.; Michael et al.) wavelengths. However, our most recent observation (at day 5327) suggests that the rate of increase of mass flux across the northeast sector of the reverse shock has accelerated, perhaps because of deceleration of the reverse shock caused by the arrival of a reflected shock created when the blast wave struck the inner ring. Resonant scattering within the supernova debris causes Lyα photons created at the reverse shock to be directed preferentially outward, resulting in a factor of ~5 difference in the observed brightness of the reverse shock in Lyα between the near and far sides of the remnant. Accounting for this effect, we compare the observed reverse-shock Lyα and Hα fluxes to infer the amount of interstellar extinction by dust as E(B-V)=0.17+/-0.01 mag. We also notice extinction by dust in the equatorial ring with E(B-V)~0.02-0.08 mag, which implies dust-to-gas ratios similar to that of the LMC. Since Hα photons are optically thin to scattering, the observed asymmetry in brightness of Hα from the near and far sides of the remnant represents a real asymmetry in the mass flux through the reverse shock of ~30%. We discuss future observational strategies that will permit us to further investigate the reverse-shock dynamics and resonant scattering of the Lyα line and to constrain better the extinction by dust within and in front of the remnant.
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