Safari, L, Amaro P, Fritzsche S, Santos JP, Tashenov S, Fratini F.
2012.
Relativistic polarization analysis of Rayleigh scattering by atomic hydrogen, Oct. Physical Review A. 86:043405.
AbstractA relativistic analysis of the polarization properties of light elastically scattered by atomic hydrogen is performed, based on the Dirac equation and second-order perturbation theory. The relativistic atomic states used for the calculations are obtained by making use of the finite basis set method and are expressed in terms of B splines and B polynomials. We introduce two experimental scenarios in which the light is circularly and linearly polarized, respectively. For each of these scenarios, the polarization-dependent angular distribution and the degrees of circular and linear polarization of the scattered light are investigated as a function of scattering angle and photon energy. Analytical expressions are derived for the polarization-dependent angular distribution which can be used for scattering by both hydrogenic as well as many-electron systems. Detailed computations are performed for Rayleigh scattering by atomic hydrogen within the incident photon energy range 0.5 to 5 keV. Particular attention is paid to the effects that arise from higher (nondipole) terms in the expansion of the electron-photon interaction.
Sanz, V, Conde J, Ambrosone A, Hernandez Y, Marchesasno V, Estrada {GG }, Ibarra {MR }, Baptista {PV}, Tian F, Tortiglione C, {de la Fuente} {JM }.
2012.
Multifunctional gold nanoparticles for gene silencing, mar. Abstracts Of Papers Of The American Chemical Society. 243: ACS - American Chemical Society
Abstractn/a
Amaro, P, Schlesser S, Guerra M, Le Bigot E-O, Isac J-M, Travers P, Santos JP, Szabo C, Gumberidze A, Indelicato P.
2012.
Absolute Measurement of the Relativistic Magnetic Dipole Transition Energy in Heliumlike Argon, Jul. Physical Review Letters. 109:043005.
AbstractThe 1s2s 3S1 - 1s2 1S0 relativistic magnetic dipole transition in heliumlike argon, emitted by the plasma of an electron-cyclotron resonance ion source, has been measured using a double-flat crystal x-ray spectrometer. Such a spectrometer, used for the first time on a highly charged ion transition, provides absolute (reference-free) measurements in the x-ray domain. We find a transition energy of 3104.1605(77) eV (2.5 ppm accuracy). This value is the most accurate, reference-free measurement done for such a transition and is in good agreement with recent QED predictions.
Trindade, AC, Canejo JP, Patrício P, Brogueira P, Teixeira PI, Godinho MH.
2012.
Hierarchical wrinkling on elastomeric Janus spheres, 2012. Journal of Materials Chemistry. 22(41):22044-22049.: The Royal Society of Chemistry
AbstractHierarchical wrinkling on elastomeric Janus spheres is permanently imprinted by swelling, for different lengths of time, followed by drying the particles in an appropriate solvent. First-order buckling with a spatial periodicity (λ11) of the order of a few microns and hierarchical structures comprising of 2nd order buckling with a spatial periodicity (λ12) of the order of hundreds of nanometers have been obtained. The 2nd order buckling features result from a Grinfeld surface instability due to the diffusion of the solvent and the presence of sol molecules.
Kanudia, A, Boavida D, van den Broek M, Cabal H, Gargiulo M, Gouveia JP, Labriet M, Seixas J, Tosato GC.
2012.
CCS infrastructure development scenarios for the integrated Iberian Peninsula and Morocco energy system, 18-22 November. GHGT_11, Conference session #9 on “CCS technology assessment and system integration”. , Kyoto International Conference Center, Japan
van den Broek, M, Mesquita P, Carneiro J, Silva J, Berghout N, Ramirez A, Gouveia JP, Seixas J, Cabal H, Martinez R, Rimi A, Boavida D, Tosato GC.
2012.
Region specific challenges of a CO2 pipeline infrastructure in the West Mediterranean area - Model results versus stakeholder views., 18-22 November. GHGT_11, on “CCS technology assessment and system integration”. , Kyoto International Conference Center, Japan.
Bahubalindruni, Ganga, Tavares, Vitor Grade, Barquinha, Duarte, Candido, Martins, Fortunato, de Oliveira PG.
2012.
Basic analog circuits with a-GIZO thin-film transistors: Modeling and simulation. 2012 International Conference on Synthesis, Modeling, Analysis and Simulation Methods and Applications to Circuit Design (SMACD).
Kuz, S, Heinicke A, Schwichtenhövel D, Mayer MP, Schlick C.
2012.
The Effect of Anthropomorphic Movements of Assembly Robots on Human Prediction. Advances in Ergonomics in Manufacturing. (
Karwowski, W., Trzcielinski, S., Eds.).:263-271., Boca Raton, FL: CRC Press
AbstractFrom a user centered point of view an important basic requirement to enable human-robot cooperation is to achieve conformity with operator's expectations of robot behavior. Therefore, this study focuses on the question, whether anthropomorphic robot movement trajectories can lead to an improved anticipation of the robot's behavior. Based on a virtual simulation environment a robotized assembly cell consisting of the assembly robot and the actual workplace was considered. In order to be able to simulate anthropomorphic movements, the human wrist trajectories of defined pick and place movements were obtained using an infrared motion capture system. The captured data were used to navigate the virtual assembly robot. Within the experiment anthropomorphic and robotic trajectories were distinguished. During the experiment, the main task of the participants was to predict the movement's destination as quickly as possible. Thus, the corresponding reaction value was analyzed to investigate the influence of anthropomorphic robot movements on human prediction in industrial environments.
Bahubalindruni, Ganga, Duarte, Candido, Tavares, Vitor Grade, Barquinha, Martins, Fortunato, de Oliveira PG.
2012.
Multipliers with transparent a-GIZO TFTs using a neural model. 20th Telecommunications Forum (TELFOR). , Belgrade
Palma, AS, Liu Y, Zhang Y, Zhang H, Luis AS, Carvalho AL, Gilbert HJ, Boraston A, Fontes CMGA, Chai W, Ten F.
2012.
Designer-oligosaccharide microarrays to decipher ligands in mammalian and prokaryotic glucan-recognition systems. Glycobiology. 22:1612-1613., Number 11
Abstractn/a
Timoteo, CG, Guilherme M, Penas D, Folgosa F, Tavares P, Pereira AS.
2012.
Desulfovibrio vulgaris bacterioferritin uses H2O2 as a co-substrate for iron oxidation and reveals DPS-like DNA protection and binding activities. BIOCHEMICAL JOURNAL. {446}:{125-133}., Number {1}
AbstractA gene encoding Bfr (bacterioferritin) was identified and isolated from the genome of Desulfovibrio vulgaris cells, and overexpressed in Escherichia coli. In vitro, H2O2 oxidizes Fe2+ ions at much higher reaction rates than O-2. The H2O2 oxidation of two Fe2+ ions was proven by Mossbauer spectroscopy of rapid freeze-quenched samples. On the basis of the Mossbauer parameters of the intermediate species we propose that D. vulgaris Bfr follows a mineralization mechanism similar to the one reported for vertebrate H-type ferritins subunits, in which a diferrous centre at the ferroxidase site is oxidized to diferric intermediate species, that are subsequently translocated into the inner nanocavity. D. vulgaris recombinant Bfr oxidizes and stores up to 600 iron atoms per protein. This Bfr is able to bind DNA and protect it against hydroxyl radical and DNase deleterious effects. The use of H2O2 as an oxidant, combined with the DNA binding and protection activities, seems to indicate a DPS (DNA-binding protein from starved cells)-like role for D. vulgaris Bfr.
Coelho, C, Mahro M, Trincao J, Carvalho ATP, Ramos MJ, Terao M, Garattini E, Leimkuehler S, Romao MJ.
2012.
The First Mammalian Aldehyde Oxidase Crystal Structure INSIGHTS INTO SUBSTRATE SPECIFICITY. Journal of Biological Chemistry. 287:40690-40702., Number 48
Abstractn/a
Pereira, AS, Timoteo CG, Guilherme M, Folgosa F, Naik SG, Duarte AG, Huynh BH, Tavares P.
2012.
Spectroscopic Evidence for and Characterization of a Trinuclear Ferroxidase Center in Bacterial Ferritin from Desulfovibrio vulgaris Hildenborough. Journal Of The American Chemical Society. {134}:{10822-10832}., Number {26}
AbstractFerritins are ubiquitous and can be found in practically all organisms that utilize Fe. They are composed of 24 subunits forming a hollow sphere with an inner cavity of similar to 80 angstrom in diameter. The main function of ferritin is to oxidize the cytotoxic Fe2+ ions and store the oxidized Fe in the inner cavity. It has been established that the initial step of rapid oxidation of Fe2+ (ferroxidation) by H-type ferritins, found in vertebrates, occurs at a diiron binding center, termed the ferroxidase center. In bacterial ferritins, however, X-ray crystallographic evidence and amino acid sequence analysis revealed a trinuclear Fe binding center comprising a binuclear Fe binding center (sites A and B), homologous to the ferroxidase center of H-type ferritin, and an adjacent mononuclear Fe binding site (site C). In an effort to obtain further evidence supporting the presence of a trinuclear Fe binding center in bacterial ferritins and to gain information on the states of the iron bound to the trinuclear center, bacterial ferritin from Desulfovibrio vulgaris (DvFtn) and its E130A variant was loaded with substoichiometric amounts of Fe2+, and the products were characterized by Mossbauer and EPR spectroscopy. Four distinct Fe species were identified: a paramagnetic diferrous species, a diamagnetic diferrous species, a mixed valence Fe2+Fe3+ species, and a mononuclear Fe2+ species. The latter three species were detected in the wild-type DvFtn, while the paramagnetic diferrous species was detected in the E130A variant. These observations can be rationally explained by the presence of a trinuclear Fe binding center, and the four Fe species can be properly assigned to the three Fe binding sites. Further, our spectroscopic data suggest that (1) the fully occupied trinuclear center supports an all ferrous state, (2) sites B and C are bridged by a mu-OH group forming a diiron subcenter within the trinuclear center, and (3) this subcenter can afford both a mixed valence Fe2+Fe3+ state and a diferrous state. Mechanistic insights provided by these new findings are discussed and a minimal mechanistic scheme involving O-O bond cleavage is proposed.