Romanian Academy

About: Romanian Academy is a archive organization based out in Bucharest, Romania. It is known for research contribution in the topics: Population & Nonlinear system. The organization has 3662 authors who have published 10491 publications receiving 146447 citations. The organization is also known as: Academia Română & Societatea Literară Română.

Quantum control design by Lyapunov trajectory tracking for dipole and polarizability coupling

Abstract: In this paper we analyze the Lyapunov trajectory tracking of the Schrodinger equation for a coupling control operator containing both a linear (dipole) and a quadratic (polarizability) term. We show numerically that the contribution of the quadratic part cannot be exploited by standard trajectory tracking tools and propose two improvements: discontinuous feedback and periodic (time-dependent) feedback. For both cases we present theoretical results and support them by numerical illustrations.

Electrochemical deposition of bioactive coatings on Ti and Ti―6Al―4V surfaces

Abstract: Passivating coatings of brushite (CaHPO 4 ·2H 2 O) were obtained on Ti and Ti–6Al–4V ELI alloy substrates by cathodic polarization. After soaking in Ringer's solution for 48 h brushite was transformed to hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 ) as confirmed by XRD, FT-IR and Raman spectroscopy. Electrochemical cyclic polarization curves of the coated biomaterials obtained in Ringer's solution at pH values of 7.1 and 8.91 as well as in Hank's Balanced Salt Solution (HBSS) at pH value of 7.4 show a nobler behavior than of the uncoated biomaterials. The coated biomaterials had lower corrosion rates than the uncoated biomaterials suggesting a protective character of the hydroxyapatite coating. Electrochemical impedance spectra (EIS) revealed capacitive behavior, owing to the protective, very resistant layer, the thickness of which increased with soaking time. The coated biomaterials presented higher electropositive open circuit potentials compared to the uncoated biomaterials as result of the protective effect of the coating. The morphology of the coatings changed with soaking time as the coatings became denser, smoother and better adhering. Hence such coatings may provide favorable structure for cell adhesion and proliferation.

Genome-wide functional analyses of plant coiled-coil NLR-type pathogen receptors reveal essential roles of their N-terminal domain in oligomerization, networking, and immunity.

Abstract: The ability to induce a defense response after pathogen attack is a critical feature of the immune system of any organism. Nucleotide-binding leucine-rich repeat receptors (NLRs) are key players in this process and perceive the occurrence of nonself-activities or foreign molecules. In plants, coevolution with a variety of pests and pathogens has resulted in repertoires of several hundred diverse NLRs in single individuals and many more in populations as a whole. However, the mechanism by which defense signaling is triggered by these NLRs in plants is poorly understood. Here, we show that upon pathogen perception, NLRs use their N-terminal domains to transactivate other receptors. Their N-terminal domains homo- and heterodimerize, suggesting that plant NLRs oligomerize upon activation, similar to the vertebrate NLRs; however, consistent with their large number in plants, the complexes are highly heterometric. Also, in contrast to metazoan NLRs, the N-terminus, rather than their centrally located nucleotide-binding (NB) domain, can mediate initial partner selection. The highly redundant network of NLR interactions in plants is proposed to provide resilience to perturbation by pathogens.