329 research outputs found
Angular dependence of magnetic properties in Ni nanowire arrays
The angular dependence of the remanence and coercivity of Ni nanowire arrays
produced inside the pores of anodic alumina membranes has been studied. By
comparing our analytical calculations with our measurements, we conclude that
the magnetization reversal in this array is driven by means of the nucleation
and propagation of a transverse wall. A simple model based on an adapted
Stoner-Wohlfarth model is used to explain the angular dependence of the
coercivity
Slow magnetic relaxation mechanisms in erbium SIMs
support by Fundação para a Ciência e a Tecnologia (FCT) under the scholarship SFRH/BD/ 84628/2012 and FRH/BPD/84173/2012. The CEMDRX group is grateful to FEDER (Programa Operacional Factores de Competitividade COMPETE) and from FCT-Fundação para a Ciência e a Tecnologia under the project PEst-C/FIS/UI0036/201
Rinitis crónica en tortugas terrestres mediterráneas
Se describen la sintomatología, alteraciones hematológicas y bioquímicas más importantes, junto con las lesiones histológicas que aparecen en la rinitis crónica de las tortugas terrestres mediterráneas
CaH Rydberg Series, Oscillator Strengths and Photoionization Cross Sections from Molecular Quantum Defect and Dyson Orbital Theories
Producción CientíficaIn this work, electron-propagator methods are applied to the calculation of the ionization potential and vertical excitation energies for several Rydberg series of the CaH molecule. The present calculations cover more highly excited states than those previously reported. In particular, excitation energies for ns (n>5), np (n>5), nd (n>4) and nf Rydberg states are given. Oscillator strengths for electronic transitions involving Rydberg states of CaH, as well as photoionization cross sections for Rydberg channels, also have been determined by using the Molecular Quantum Defect Orbital approach. Good agreement has been found with the scarce comparative data that are available for oscillator strengths. To our knowledge, predictions of photoionization cross sections from the outermost orbital of CaH are made here for the first time. A Cooper minimum and mixed atomic orbital character in some of the Dyson orbitals are among the novel features of these present calculationsJunta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA330U13
Chronic rhinitis associated with herpesviral infection in captive spur-thighed tortoises from Spain
An epidemic of chronic rhinitis in a population of 50 captive spur-thighed tortoises (Testudo graeca graeca) from Palafrugell (Girona, Spain) is described, in which eight animals died and 12 were euthanatized to perform necropsies and post-mortem studies. The main clinical sign was a bilateral, seromucous rhinitis often accompanied by stomatitis and glossitis. Hematology and serum biochemistry were performed in 33 of the 50 ill animals and in 29 healthy tortoises from three disease-free populations. Lymphocyte count, aspartate aminotransferase (AST) activity, and a-globulin levels were significantly higher in the animals from the sick poptulation. The heterophil count was significantly lower in the sick animals. Some of the diseased tortoises also showed a normocytic-normochromic anemia. Lesions were restricted to the respiratory system and oral cavity. Marked epithelial hyperplasia and presence of a severe mixed inflammatory infiltrate in the epithelium of the oral, nasal, and tracheal miucosae were observed. Electron mi- croscopy demonstrated the presence of mntracytoplasmic and intranuclear viral particles of the size, shape, and distribution pattern typical of a herpesvirus. Key words: Chronic rhinitis, epidemic, herpesviral infection, spur-thighed tortoise, Testudo graeca graeca
Excitation energies, photoionization cross sections, and asymmetry parameters of the methyl and silyl radicals
Producción CientíficaVertical excitation energies of the methyl and silyl radicals were inferred from ab initio electron propagator calculations on the electron affinities of CH3 + and SiH3 +. Photoionization cross sections and angular distribution of photoelectrons for the outermost orbitals of both CH3 and SiH3 radicals have been obtained with the Molecular Quantum Defect Orbital method. The individual ionization cross sections corresponding to the Rydberg channels to which the excitation of the ground state’s outermost electron gives rise are reported. Despite the relevance of methyl radical in atmospheric chemistry and combustion processes, only data for the photon energy range of 10–11 eV seem to be available. Good agreement has been found with experiment for photoionization cross section of this radical. To our knowledge, predictions of the above mentioned photoionization parameters on silyl radical are made here for the first time, and we are not aware of any reported experimental measurements. An analysis of our results reveals the presence of a Cooper minimum in the photoionization of the silyl radical. The adequacy of the two theoretical procedures employed in the present work is discussed.Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA330U13
Highly fluorinated erbium(III) complexes for emission in the C-band
Two highly fluorinated Er3+ complexes with three 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionate (fod) groups and either bipyridine (bipy) or bathophenantholine (bath) as the ancillary ligand emitting at the C-band (third communication window for fiber transmission) are presented. These complexes are the result of a design process aimed at decreasing the vibrational quenching from high frequency oscillators. The structure of [Er(fod)3(bipy)] has been elucidated by single-crystal X-ray diffraction, while Sparkle/PM6 and Sparkle/PM7 semi-empirical calculations have been used to model the ground state geometry for [Er(fod)3(bath)]. Photoluminescence studies confirm sensitization of the Er3+ ions by antenna effect, leading to NIR emission at 1.53 μm. This energy transfer proves to be more efficient for [Er(fod)3(bath)] as a result of the bulkier and more rigid structure of bath diimide. The good thermal stability of the materials up to over 200 °C allows envisaging their use in erbium-doped waveguides, NIR-OLEDs or other optoelectronic devices
Perioperative stress response in dogs undergoing elective surgery : variations in behavioural, neuroendocrine, immune and acute phase responses
The aim of this trial was to describe the behavioural, neuroendocrine, immune and acute phase stress responses in dogs undergoing elective surgery in normal, clinical practice conditions. Sixteen dogs were submitted to elective orchiectomy or ovariohysterectomy using a standardised surgical protocol. Each animal was confined to the Intensive Care Unit during pre- and post-surgery and perioperative behavioural, neuroendocrine, immune and acute phase responses were studied. Behavioural categories, cortisol, prolactin, white blood cell, C-reactive protein and haptoglobin variation were evaluated. Values at different times were compared with basal values shown by the dog in its usual environment. Communicative and explorative behaviours showed high occurrence pre-surgery and were inhibited post-surgery. Decreases in post-surgery activity, interactive behaviours and changes in waking/sleeping patterns were observed. The most sensitive marker of psychological stress, cortisol, in comparison with basal values, showed a significant increase both during pre- and post-surgery confinement in the ICU cage. Prolactin values were characterised by a significant decrease early into the post-surgery period. The immune response was characterised by long-term neutrophilia and monocytosis, but by short-term lymphopaenia and eosinopaenia, limited to the early post-operative period. With regard to the acute phase response, both C-reactive protein and haptoglobin showed a long-term increase, post-surgery. Changes in behavioural, haematological and biochemical markers showed that perioperative stress represents a major challenge to dog welfare
Efficient design and optimization of bio-photonic sensing cells (BICELLs) for label free biosensing
In previous works we demonstrated the benefits of using micro–nano patterning materials to be used as bio-photonic sensing cells (BICELLs), referred as micro–nano photonic structures having immobilized bioreceptors on its surface with the capability of recognizing the molecular binding by optical transduction. Gestrinone/anti-gestrinone and BSA/anti-BSA pairs were proven under different optical configurations to experimentally validate the biosensing capability of these bio-sensitive photonic architectures. Moreover, Three-Dimensional Finite Difference Time Domain (FDTD) models were employed for simulating the optical response of these structures. For this article, we have developed an effective analytical simulation methodology capable of simulating complex biophotonic sensing architectures. This simulation method has been tested and compared with previous experimental results and FDTD models. Moreover, this effective simulation methodology can be used for efficiently design and optimize any structure as BICELL. In particular for this article, six different BICELL's types have been optimized. To carry out this optimization we have considered three figures of merit: optical sensitivity, Q-factor and signal amplitude. The final objective of this paper is not only validating a suitable and efficient optical simulation methodology but also demonstrating the capability of this method for analyzing the performance of a given number of BICELLs for label-free biosensing
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