Angerhausen D.,University of Hamburg |
Angerhausen D.,Rensselaer Polytechnic Institute |
Sapers H.,University of Western Ontario |
Citron R.,University of Colorado at Boulder |
And 5 more authors.
Astrobiology | Year: 2013
Extrasolar Earth and super-Earth planets orbiting within the habitable zone of M dwarf host stars may play a significant role in the discovery of habitable environments beyond Earth. Spectroscopic characterization of these exoplanets with respect to habitability requires the determination of habitability parameters with respect to remote sensing. The habitable zone of dwarf stars is located in close proximity to the host star, such that exoplanets orbiting within this zone will likely be tidally locked. On terrestrial planets with an icy shell, this may produce a liquid water ocean at the substellar point, one particular "Eyeball Earth" state. In this research proposal, HABEBEE: exploring the HABitability of Eyeball-Exo-Earths, we define the parameters necessary to achieve a stable icy Eyeball Earth capable of supporting life. Astronomical and geochemical research will define parameters needed to simulate potentially habitable environments on an icy Eyeball Earth planet. Biological requirements will be based on detailed studies of microbial communities within Earth analog environments. Using the interdisciplinary results of both the physical and biological teams, we will set up a simulation chamber to expose a cold- and UV-tolerant microbial community to the theoretically derived Eyeball Earth climate states, simulating the composition, atmosphere, physical parameters, and stellar irradiation. Combining the results of both studies will enable us to derive observable parameters as well as target decision guidance and feasibility analysis for upcoming astronomical platforms. Copyright © 2013, Mary Ann Liebert, Inc. 2013.
Simioni A.R.,University Do Vale Do Paraba |
Primo F.L.,University of Sao Paulo |
Tedesco A.C.,University of Sao Paulo
Journal of Laser Applications | Year: 2012
The aim of this study was to evaluate the potential application of biodegradable nanoparticles containing a photosensitizer in photodynamic therapy. The poly (D,L lactic-co-glycolic acid) nanoparticles were studied by steady-state techniques, time-resolved fluorescence, and laser flash photolysis. The external morphology of the nanoparticles was established by scanning electron microscopy, and the biological activity was evaluated by in vitro cell culture by 3-(4,5 dimethyl-thiazol-2,5 biphenyl) tetrazolium bromide assay. The particles were spherical in shape exhibiting a 435 nm diameter with a low tendency to aggregate. The loading efficiency was 77. The phthalocyanine-loaded- nanoparticles maintained their photophysical behavior after encapsulation. The cellular viability was determined, obtaining 70 of cellular death. All the performed physical-chemical, photophysical, and photobiological measurements indicated that the phthalocyanine-loaded-nanoparticles are a promising drug delivery system for photodynamic therapy and photoprocesses. © 2012 Laser Institute of America.
Krabbe A.C.,University do Vale do Paraba |
Rosa D.A.,University do Vale do Paraba |
Dors O.L.,University do Vale do Paraba |
Pastoriza M.G.,Federal University of Rio Grande do Sul |
And 6 more authors.
Monthly Notices of the Royal Astronomical Society | Year: 2013
We present an observational study about the impacts of the interactions on the electron density of HII regions located in seven systems of interacting galaxies. The data consist of long-slit spectra in the range 4400-7300 Å, obtained with the Gemini Multi-Object Spectrograph at Gemini South (GMOS-S). The electron density was determined using the ratio of emission lines [S II] Λ6716/Λ6731. Our results indicate that the electron density estimates obtained of HII regions from our sample of interacting galaxies are systematically higher than those derived for isolated galaxies. The mean electron density values of interacting galaxies are in the range of Ne = 24-532 cm-3, while those obtained for isolated galaxies are in the range of Ne =40-137 cm-3.Comparing the observed emission lines with predictions of photoionization models, we verified that almost all the HII regions of the galaxies AM 1054A, AM 2058B and AM 2306B have emission lines excited by shock gas. For the remaining galaxies, only few HII regions have emission lines excited by shocks, such as in AM 2322B (one point) and AM 2322A (four points). No correlation is obtained between the presence of shocks and electron densities. Indeed, the highest electron density values found in our sample do not belong to the objects with gas shock excitation. We emphasize the importance of considering these quantities especially when the metallicity is derived for these types of systems. © 2013 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.