Search results for "INTERACTION"
showing 10 items of 5710 documents
Orbitally dependent kinetic exchange in cobalt(II) pairs: origin of the magnetic anisotropy
2003
Abstract A comprehensive theoretical study of the magnetic exchange between Co 2+ ions is reported. Using the microscopic background we deduce the general Hamiltonian for a corner-shared bioctahedral system involving kinetic exchange, spin–orbit coupling and low-symmetry local crystal field. This Hamiltonian acting within orbitally degenerate ground manifold 4 ( T 1g ) A ⊗ 4 ( T 1g ) B of the cobalt pair is expressed in terms of orbital and spin operators. We elucidate the major electronic factors controlling the exchange anisotropy in the Co(II) pairs. The degree of the magnetic anisotropy is shown to depend on the strength of the cubic crystal field and on the relative efficiency of two k…
Magnetic properties of six-coordinated high-spin cobalt(II) complexes: Theoretical background and its application
2008
Abstract In this contribution we study and analyse the influence of the different parameters involved in the magnetic susceptibility of six-coordinated high-spin Co(II) complexes. We propose an empirical expression to fit the magnetic susceptibility of polycrystalline samples of mononuclear Co(II) complexes with an axial distortion, the variable parameters being Δ (axial distortion), α (orbital reduction factor) and λ (spin–orbit coupling). This expression avoids solving the 12 × 12 matrix associated to the distortion of the 4 T 1g term. In order to take into account the magnetic coupling ( J ) in the polynuclear Co(II) complexes, a perturbational approach is proposed to describe their magn…
Magnetic exchange between metal ions with unquenched orbital angular momenta: basic concepts and relevance to molecular magnetism
2010
This review article is a first attempt to give a systematic and comprehensive description (in the framework of the unified theoretical approach) of the exchange interactions in polynuclear systems based on orbitally degenerate metal ions in the context of their relevance to the modern molecular magnetism. Interest in these systems is related to the fundamental problems of magnetism and at the same time steered by a number of impressive potential applications of molecular magnets, like high-density memory storage units, nanoscale qubits, spintronics and photoswitchable devices. In the presence of orbital degeneracy, the conventional spin Hamiltonian (Heisenberg–Dirac–van Vleck model) becomes…
Functional consequences of prey acclimation to ocean acidification for the prey and its predator
2016
Ocean acidification is the suite of chemical changes to the carbonate system of seawater as a consequence of anthropogenic carbon dioxide (CO2) emissions. Despite a growing body of evidences demonstrating the negative effects of ocean acidification on marine species, the consequences at the ecosystem level are still unclear. One factor limiting our ability to upscale from species to ecosystem is the poor mechanistic understanding of the functional consequences of the observed effects on organisms. This is particularly true in the context of species interactions. The aim of this work was to investigate the functional consequence of the exposure of a prey (the mussel Brachidontes pharaonis) t…
Information dynamics of brain-heart physiological networks during sleep
2014
This study proposes an integrated approach, framed in the emerging fields of network physiology and information dynamics, for the quantitative analysis of brain-heart interaction networks during sleep. With this approach, the time series of cardiac vagal autonomic activity and brain wave activities measured respectively as the normalized high frequency component of heart rate variability and the EEG power in the δ, θ, Ï, and β bands, are considered as realizations of the stochastic processes describing the dynamics of the heart system and of different brain sub-systems. Entropy-based measures are exploited to quantify the predictive information carried by each (sub)system, and to dissec…
Dental CBCT equipment and performance issues
2012
Dental cone beam computed tomography (CBCT), also known as digital volumetric tomography was developed in the late 1990s and is now increasingly available in clinical practice. It can provide high resolution cross-sectional images of teeth and the maxillofacial region with applications in all branches of dentistry. As a new imaging modality, there were no established suspension levels at a European level. A literature review, encompassing scientific, professional publications and existing national guidelines was performed in an attempt to develop a set of suspension levels for dental CBCT, using additional expert opinion from the members of the European Academy of dento-maxillo-facial radio…
Subcellular localization of bacteriophage PRD1 proteins in Escherichia coli
2014
Bacteria possess an intricate internal organization resembling that of the eukaryotes. The complexity is especially prominent at the bacterial cell poles, which are also known to be the preferable sites for some bacteriophages to infect. Bacteriophage PRD1 is a well-known model serving as an ideal system to study structures and functions of icosahedral internal membrane-containing viruses. Our aim was to analyze the localization and interactions of individual PRD1 proteins in its native host Escherichia coli. This was accomplished by constructing a vector library for production of fluorescent fusion proteins. Analysis of solubility and multimericity of the fusion proteins, as well as their …
A Straightforward Electroactive π-Extended Tetrathiafulvalene (exTTF) Building Block
2012
The synthesis and X-ray structure of a new and readily available exTTF derivative (6) bearing a methyltriphenylphosphonium bromide moiety as a new building block for the construction of electroactive molecules is reported. The phosphonium salt 6, which was prepared in one step from 2-hydroxymethyl-exTTF as a stable yellow solid in 84 % yield, efficiently undergoes Wittig olefination reactions with a variety of aldehydes to predominantly form the E isomer. Electronic spectra and cyclic voltammetry of the novel compounds reveal the electronic communication between the electroactive units.
Le radici del futuro. Il Micromuseo Immateriale del Grano e del Pane. Un progetto design-driven per il patrimonio culturale rurale
2023
Realizzato nel 2016 nel borgo rurale Santa Rita nei pressi di Caltanissetta, il Micromuseo Immateriale del Grano e del Pane è un piccolo ecomuseo di identità e territorio, che coniuga la dimensione storico-antropologica della memoria con la dimensione scientifico-didattica legata ai saperi del grano e del pane. Nel palazzetto baronale, ex scuola del borgo, trovano posto installazioni interattive/sensoriali e artefatti di comunicazione immateriali (infografiche, animazioni, documentari) che costituiscono il focus dell’esperienza di visita al museo. Un progetto design-driven di “riuso” del patrimonio culturale come motore di sviluppo, sostenibile e condiviso, concepito e realizzato (con tecno…
Kinematic splitting algorithm for fluid–structure interaction in hemodynamics
2013
Abstract In this paper we study a kinematic splitting algorithm for fluid–structure interaction problems. This algorithm belongs to the class of loosely-coupled fluid–structure interaction schemes. We will present stability analysis for a coupled problem of non-Newtonian shear-dependent fluids in moving domains with viscoelastic boundaries. Fluid flow is described by the conservation laws with nonlinearities in convective and diffusive terms. For simplicity of presentation the structure is modelled by the generalized string equation, but the results presented in the paper may be generalized to more complex structure models. The arbitrary Lagrangian–Eulerian approach is used in order to take…