25,044 research outputs found
Testing nitrogen fertilizer sources to increase N-Use efficiency of common beans in the Brazilian savanna.
Improving the Knowledge on Seismogenic Sources in the Lower Tagus Valley for Seismic Hazard Purposes
The Lower Tagus Valley, that includes the metropolitan area of Lisbon, has been struck by several earthquakes which produced significant material damage and loss of lives. Their exact location remains unknown. Our goal is to shed some light into the seismogenic sources in the area using seismic reflection and geological data. In areas with no seismic coverage, potential-field data interpretation was carried out. Seismicity was overlaid to the potential seismogenic structures and high-resolution data was acquired in order to confirm which structures have been active into the Quaternary. Three major fault-zones affecting the Neogene were identified: V. F. Xira, Samora-Alcochete and Pinhal Novo. For the first fault, strong evidences suggest it is active. The other two fault-zones and other structures previously unknown can be correlated with several epicentres. Empirical relationships between maximum moment magnitude and fault area indicate that MW > 6.5 earthquakes can be expected for the larger structures
Dinâmica das populações de abius em uma área sob manejo na Floresta Nacional do Tapajós, PA.
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Mechanical properties of flexible film based on starch and passion fruit mesocarp flour added of nanoparticles.
Challenges and opportunities for livestock production in natural pastures: the case of Brazilian Pampa Biome.
Development and characterization of flexible film based on starch and passion fruit mesocarp flour with nanoparticles.
QM/MM MD studies of polyester synthesis/hydrolysis
The world is suffering the consequences of plastic pollution, however modern societies remain heavily reliant on plastics. More sustainable alternatives are actively being sought-after. Enzymatic synthesis can offer a more sustainable route for polyester synthesis. Nevertheless, there are still limitations, such as limited activity and selectivity for some monomers, unfavorable compatibility in chemoenzymatic reactions and low stability under harsh reactions conditions. We have studied the catalytic mechanisms for polycaprolactone hydrolysis/synthesis by the wildtype enzymes Archaeoglobus fulgidus carboxylesterase (AfEST) and Candida antarctica lipase B (CaLB) and respective enzyme variants by performing Quantum Mechanics/Molecular Mechanics Molecular Dynamics simulations [1-3]. Our results give important insights towards the design of new enzyme variants combining good activity with high thermostability.
[1] Almeida, B., Figueiredo, P., Carvalho, A. PCL enzymatic hydrolysis: a mechanistic study. ACS Omega. Doi: 10.1021/acsomega.9b00345.
[2] Carvalho, A. T. P., Dourado, D. F. A. R., Skvortsov, T., de Abreu M., Ferguson, L. J., Quinn, D. J., Moody, T. S. Huang, M. Spatial requirement for PAMO for transformation of non-native linear substrates. Phys. Chem. Chem. Phys. 2018.
[3] Dourado D. F. A. R., Swart M., Carvalho A. T. P. Why the flavin dinucleotide cofactor needs to be covalently linked to Complex II of the electron transport chain for conversion of FADH2 to FAD. Chem. – Eur J. 2018
Bleaching of sol-gel glass film with embedded gold nanoparticles by thermal poling
Gold clusters embedded in glass are expected to be hard to dissolve in the form of ions since gold is essentially a nonreactive metal. In spite of that, bleaching of Au-doped nanocomposite sol-gel glass film on a soda-lime glass substrate is demonstrated in which electric-field thermal poling is employed to effectively dissolve randomly distributed gold nanoparticles (15 nm in diameter) embedded in a low conductivity sol-gel glass film with a volume filling factor as small as 2.3%. The surface plasmon absorption band at 520 nm is suppressed in the region covered by the anodic electrode. The phenomenon is explained by the ionization of the gold nanoparticles and the redistribution of gold ions in the glass matrix due to the action of the extremely high electrostatic field locally developed during poling
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