Showing papers by "University of Coimbra published in 2007"
TL;DR: In this paper, the authors investigate the response of epsilon-near-zero metamaterials and plasmonic materials to electromagnetic source excitation and propose the use of these media for tailoring the phase of radiation pattern of arbitrary sources.
Abstract: In this work, we investigate the response of epsilon-near-zero metamaterials and plasmonic materials to electromagnetic source excitation. The use of these media for tailoring the phase of radiation pattern of arbitrary sources is proposed and analyzed numerically and analytically for some canonical geometries. In particular, the possibility of employing planar layers, cylindrical shells, or other more complex shapes made of such materials in order to isolate two regions of space and to tailor the phase pattern in one region, fairly independent of the excitation shape present in the other region, is demonstrated with theoretical arguments and some numerical examples. Physical insights into the phenomenon are also presented and discussed together with potential applications of the phenomenon.
981 citations
TL;DR: The generation of transgenic mice that express a ChR2-YFP fusion protein in the CNS for in vivo activation and mapping of neural circuits is reported, demonstrating a highly reproducible, light-dependent activation of neurons and precise control of firing frequency in vivo.
801 citations
TL;DR: Nine recommendations for the management of fibromyalgia syndrome were developed using a systematic review and expert consensus using a Delphi process.
Abstract: Objective: To develop evidence-based recommendations for the management of fibromyalgia syndrome. Methods: A multidisciplinary task force was formed representing 11 European countries. The design o ...
759 citations
TL;DR: It is shown that mice with genetic deletion of Sapap3 exhibit increased anxiety and compulsive grooming behaviour leading to facial hair loss and skin lesions; both behaviours are alleviated by a selective serotonin reuptake inhibitor.
Abstract: Obsessive-compulsive disorder (OCD) is an anxiety-spectrum disorder characterized by persistent intrusive thoughts (obsessions) and repetitive actions (compulsions). Dysfunction of cortico-striato-thalamo-cortical circuitry is implicated in OCD, although the underlying pathogenic mechanisms are unknown. SAP90/PSD95-associated protein 3 (SAPAP3; also known as DLGAP3) is a postsynaptic scaffolding protein at excitatory synapses that is highly expressed in the striatum. Here we show that mice with genetic deletion of Sapap3 exhibit increased anxiety and compulsive grooming behaviour leading to facial hair loss and skin lesions; both behaviours are alleviated by a selective serotonin reuptake inhibitor. Electrophysiological, structural and biochemical studies of Sapap3-mutant mice reveal defects in cortico-striatal synapses. Furthermore, lentiviral-mediated selective expression of Sapap3 in the striatum rescues the synaptic and behavioural defects of Sapap3-mutant mice. These findings demonstrate a critical role for SAPAP3 at cortico-striatal synapses and emphasize the importance of cortico-striatal circuitry in OCD-like behaviours.
718 citations
TL;DR: In the first part of the essay, the author states that the "abyssal" cartographical lines that used to demarcate the Old and the New World during colonial times are still alive in the structure of modern occidental thought and remain constitutive of the political and cultural relations held by the contemporary world system.
Abstract: In the first part of the essay, the author states that the "abyssal" cartographical lines that used to demarcate the Old and the New World during colonial times are still alive in the structure of modern occidental thought and remain constitutive of the political and cultural relations held by the contemporary world system. Global social iniquity would thus be strictly related to global cognitive iniquity, in such a way that the struggle for a global social justice requires the construction of a "post-abyssal" thought.
587 citations
Centre national de la recherche scientifique1, Joseph Fourier University2, Institut national de la recherche agronomique3, University of Coimbra4, Sewanee: The University of the South5, Stockholm University6, Hebrew University of Jerusalem7, University of Oldenburg8, Macaulay Institute9, Aristotle University of Thessaloniki10, Tel Aviv University11, Université de Sherbrooke12
TL;DR: This work shows the applicability of a set of protocols that can be widely applied to assess the impacts of global change drivers on species, communities and ecosystems.
531 citations
TL;DR: The results indicate that the encapsulation of insulin into mucoadhesive nanoparticles was a key factor in the improvement of its oral absorption and oral bioactivity.
Abstract: To evaluate the pharmacological activity of insulin-loaded alginate/chitosan nanoparticles following oral dosage in diabetic rats. Nanoparticles were prepared by ionotropic pre-gelation of an alginate core followed by chitosan polyelectrolyte complexation. In vivo activity was evaluated by measuring the decrease in blood glucose concentrations in streptozotocin induced, diabetic rats after oral administration and flourescein (FITC)-labelled insulin tracked by confocal microscopy. Nanoparticles were negatively charged and had a mean size of 750 nm, suitable for uptake within the gastrointestinal tract due to their nanosize range and mucoadhesive properties. The insulin association efficiency was over 70% and insulin was released in a pH-dependent manner under simulated gastrointestinal conditions. Orally delivered nanoparticles lowered basal serum glucose levels by more than 40% with 50 and 100 IU/kg doses sustaining hypoglycemia for over 18 h. Pharmacological availability was 6.8 and 3.4% for the 50 and 100 IU/kg doses respectively, a significant increase over 1.6%, determined for oral insulin alone in solution and over other related studies at the same dose levels. Confocal microscopic examinations of FITC-labelled insulin nanoparticles showed clear adhesion to rat intestinal epithelium, and internalization of insulin within the intestinal mucosa. The results indicate that the encapsulation of insulin into mucoadhesive nanoparticles was a key factor in the improvement of its oral absorption and oral bioactivity.
529 citations
TL;DR: In this article, the experimental measurements of the pressure (0.10 < p/MPa < 10.0) and temperature (293.15 < T/K < 393.15) dependence of the density and derived thermodynamic properties, such as the isothermal compressibility, the isobaric expansivity, the thermal pressure coefficient, and the pressure dependence of heat capacity of several imidazolium-based ionic liquids (ILs), were addressed.
Abstract: This work addresses the experimental measurements of the pressure (0.10 < p/MPa < 10.0) and temperature (293.15 < T/K < 393.15) dependence of the density and derived thermodynamic properties, such as the isothermal compressibility, the isobaric expansivity, the thermal pressure coefficient, and the pressure dependence of the heat capacity of several imidazolium-based ionic liquids (ILs), namely, 1-butyl-3-methylimidazolium tetrafluoroborate, [bmim][BF4]; 3-methyl-1-octylimidazolium tetrafluoroborate, [omim][BF4]; 1-hexyl-3-methylimidazolium hexafluorophosphate, [hmim][PF6]; 3-methyl-1-octylimidazolium hexafluorophosphate, [omim][PF6]; 1-butyl2,3-dimethylimidazolium hexafluorophosphate, [bmmim][PF6]; and 1-butyl-3-methylimidazolium trifluoromethansulfonate, [bmim][CF3SO3]. These ILs were chosen to provide an understanding of the influence of the cation alkyl chain length, the number of cation substitutions, and the anion influence on the properties under study. The influence of water content in the density was also studied for the most hydrophobic IL used, [omim][PF6]. A simple ideal-volume model was employed for the prediction of the imidazolium molar volumes at ambient conditions, which proved to agree well with the experimental results.
372 citations
Bryn Mawr College1, University of Vermont2, University of Helsinki3, University of Southern Denmark4, Columbia University5, National Taiwan University6, Babeș-Bolyai University7, University of Cologne8, Ankara University9, McGill University10, University of Coimbra11, Katholieke Universiteit Leuven12, Chuo University13, University of Missouri14, Norwegian University of Science and Technology15, The Chinese University of Hong Kong16, University of Pittsburgh17, Yonsei University18, University of Adelaide19, Harran University20, University of Zurich21, Harvard University22, Medical University of Warsaw23, Chung Shan Medical University24, Centre national de la recherche scientifique25, Mykolas Romeris University26, Erasmus University Rotterdam27
TL;DR: The authors compared parents' ratings of behavioral and emotional problems on the Child Behavior Checklist (Achenbach, 1991; Achenbach & Rescorla, 2001) for general population samples of children age 5.
Abstract: This study compared parents' ratings of behavioral and emotional problems on the Child Behavior Checklist (Achenbach, 1991;Achenbach & Rescorla, 2001) for general population samples of children age...
364 citations
University of Vermont1, Babeș-Bolyai University2, University of Cologne3, Ankara University4, McGill University5, University of Coimbra6, Katholieke Universiteit Leuven7, Chuo University8, University of Missouri9, Norwegian University of Science and Technology10, The Chinese University of Hong Kong11, University of Pittsburgh12, Yonsei University13, University of Adelaide14, Harran University15, University of Zurich16, Medical University of Warsaw17, Chung Shan Medical University18, Mykolas Romeris University19, Erasmus University Rotterdam20, Bryn Mawr College21, University of Helsinki22, University of Southern Denmark23, Columbia University24, National Taiwan University25
TL;DR: Fit indices strongly supported the correlated 8-syndrome structure of the Child Behavior Checklist in each of 30 societies, which support use of the syndromes in diverse societies.
Abstract: There is a growing need for multicultural collaboration in child mental health services, training, and research. To facilitate such collaboration, this study tested the 8-syndrome structure of the Child Behavior Checklist (CBCL) in 30 societies. Parents' CBCL ratings of 58,051 6- to 18-year-olds were subjected to confirmatory factor analyses, which were conducted separately for each society. Societies represented Asia; Africa; Australia; the Caribbean; Eastern, Western, Southern, and Northern Europe; the Middle East; and North America. Fit indices strongly supported the correlated 8-syndrome structure in each of 30 societies. The results support use of the syndromes in diverse societies.
362 citations
TL;DR: A2A receptors play an important fine-tuning role, boosting the efficiency of glutamatergic information flow in the indirect pathway by exerting control, either pre- and/or post-synaptically, over other key modulators of glutatopallidal synapses, including D2 receptors, group I metabotropic mGlu5 glutamate receptors and cannabinoid CB1 receptors, and by triggering the cAMP-protein kinase A signaling cascade.
TL;DR: This paper develops, analyze, and test a new algorithm for the global minimization of a function subject to simple bounds without the use of derivatives, and shows that the resulting algorithm is highly competitive with other global optimization methods also based on function values.
Abstract: In this paper we develop, analyze, and test a new algorithm for the global minimization of a function subject to simple bounds without the use of derivatives. The underlying algorithm is a pattern search method, more specifically a coordinate search method, which guarantees convergence to stationary points from arbitrary starting points. In the optional search phase of pattern search we apply a particle swarm scheme to globally explore the possible nonconvexity of the objective function. Our extensive numerical experiments showed that the resulting algorithm is highly competitive with other global optimization methods also based on function values.
TL;DR: First direct in vivo evidence that caffeine and A(2A) receptor antagonists afford a protection against Abeta-induced amnesia, which prompts their interest for managing Alzheimer's disease is provided.
TL;DR: In this article, the rotational symmetry number for different molecular configurations and how to apply them to transition state theory is discussed. But special care is advised in the evaluation of symmetry numbers in the following situations: (i) reaction is symmetric, (ii) if reactants and/or transition states are chiral, (iii) if the reaction has multiple conformers for reactants or transition states and, (iv) if there is an internal rotation of part of the molecular system.
Abstract: This article shows how to evaluate rotational symmetry numbers for different molecular configurations and how to apply them to transition state theory. In general, the symmetry number is given by the ratio of the reactant and transition state rotational symmetry numbers. However, special care is advised in the evaluation of symmetry numbers in the following situations: (i) if the reaction is symmetric, (ii) if reactants and/or transition states are chiral, (iii) if the reaction has multiple conformers for reactants and/or transition states and, (iv) if there is an internal rotation of part of the molecular system. All these four situations are treated systematically and analyzed in detail in the present article. We also include a large number of examples to clarify some complicated situations, and in the last section we discuss an example involving an achiral diasteroisomer.
TL;DR: In this article, the authors present a tutorial introduction to two important senses for biological and robotic systems -inertial and visual perception, and discuss the complementarity of these sensors, describe some fundamental approaches to fusing their outputs and survey the field.
Abstract: In this paper we present a tutorial introduction to two important senses for biological and robotic systems — inertial and visual perception. We discuss the fundamentals of these two sensing modalities from a biological and an engineering perspective. Digital camera chips and micro-machined accelerometers and gyroscopes are now commodities, and when combined with today's available computing can provide robust estimates of self-motion as well 3D scene structure, without external infrastructure. We discuss the complementarity of these sensors, describe some fundamental approaches to fusing their outputs and survey the field.
TL;DR: In this article, the authors investigated the theory of the supercoupling, anomalous tunneling effect, and field confinement originally identified by Silveirinha and Engheta and demonstrated the possibility of using materials with permittivity near zero to drastically improve the transmission of electromagnetic energy through a narrow irregular channel with very subwavelength transverse cross section.
Abstract: In this work, we investigate the detailed theory of the supercoupling, anomalous tunneling effect, and field confinement originally identified by Silveirinha and Engheta [Phys. Rev. Lett. 97, 157403 (2006)], where we demonstrated the possibility of using materials with permittivity $\ensuremath{\epsilon}$ near zero to drastically improve the transmission of electromagnetic energy through a narrow irregular channel with very subwavelength transverse cross section. Here, we present additional physical insights, describe applications of the tunneling effect in relevant waveguide scenarios (e.g., the ``perfect'' or ``super'' waveguide coupling), and study the effect of metal losses in the metallic walls and the possibility of using near-zero $\ensuremath{\epsilon}$ materials to confine energy in a subwavelength cavity with gigantic field enhancement. In addition, we systematically study the propagation of electromagnetic waves through narrow channels filled with anisotropic near-zero $\ensuremath{\epsilon}$ materials. It is demonstrated that these materials may have interesting potentials, and that for some particular geometries, the reflectivity of the channel is independent of the specific dimensions or parameters of near-zero $\ensuremath{\epsilon}$ transition. We also describe several realistic metamaterial implementations of the studied problems, based on standard metallic waveguides, microstrip line configurations, and wire media.
TL;DR: People over 70 do want to be involved in their care but their definition of involvement is more focussed on the 'caring relationship', 'person-centred approach' and 'receiving information' than on 'active participation in decision making'.
TL;DR: Evaluating the performance of commercial ion exchange resins for removing chromium trivalent from industrial effluents found two resins were tested: a chelating exchange resin (Diaion CR11) and a weak cationic resin (Amberlite IRC86).
TL;DR: In this article, experimental density measurements are reported, and derived thermodynamic properties, such as the isothermal compressibility, the isobaric expansivity, and the thermal pressure coefficient are presented as Supporting Information for several imidazolium-based ionic liquids (ILs), namely, 1-ethyl-3-methyl-imidazolate bis(trifluoromethylsulfonyl)imide [C2mim][NTf2], 1-heptyl-3]-methyl-IMIDazolate [C7mim
Abstract: Experimental density measurements are reported, and the derived thermodynamic properties, such as the isothermal compressibility, the isobaric expansivity, and the thermal pressure coefficient are presented as Supporting Information for several imidazolium-based ionic liquids (ILs), namely, 1-ethyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide [C2mim][NTf2], 1-heptyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide [C7mim][NTf2], 1-octyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide [C8mim][NTf2], 1-ethyl-3-methyl-imidazolium tetrafluoroborate [C2mim][BF4], and 1-butyl-3-methyl-imidazolium tricyanomethane [C4mim][C(CN)3] in the pressure (0.10 < p/MPa < 30.00) and temperature (293.15 < T/K < 393.15) domains. These ILs were chosen to provide an understanding of the influence of the cation alkyl chain length and the anion influence on the properties under study. Experimental densities are correlated with the Tait equation with an average absolute deviation (AAD) less than 0.04 %. Expe...
TL;DR: Efficient methods for performing the computations through Monte Carlo simulation, analyze the complexity, and assess the accuracy of the presented algorithms are presented and the efficiency of these methods empirically are tested.
TL;DR: This paper proposes an approach to calibrate off-the-shelf cameras and inertial sensors to have a useful integrated system to be used in static and dynamic situations.
Abstract: This paper proposes an approach to calibrate off-the-shelf cameras and inertial sensors to have a useful integrated system to be used in static and dynamic situations. When both sensors are integrated in a system their relative pose needs to be determined. The rotation between the camera and the inertial sensor can be estimated, concurrently with camera calibration, by having both sensors observe the vertical direction in several poses. The camera relies on a vertical chequered planar target and the inertial sensor on gravity to obtain a vertical reference. Depending on the setup and system motion, the translation between the two sensors can also be important. Using a simple passive turntable and static images, the translation can be estimated. The system needs to be placed in several poses and adjusted to turn about the inertial sensor centre, so that the lever arm to the camera can be determined. Simulation and real data results are presented to show the validity and simple requirements of the proposed methods.
TL;DR: The results indicate that BDNF increases the abundance of NMDA receptors and their delivery to the plasma membrane, thereby upregulating receptor activity in cultured hippocampal neurons.
TL;DR: It is shown that BDNF acutely up-regulates the protein levels of AMPA receptor subunits in hippocampal neurons and induces the delivery ofAMPA receptors to the synapse.
TL;DR: The results indicate that the iNOS isoform plays a predominant role in leukostasis and BRB breakdown, and the mechanism involves ICAM-1 upregulation and tight junction protein downregulation.
Abstract: PURPOSE. Nitric oxide (NO) is involved in leukostasis and bloodretinal barrier (BRB) breakdown in the early stages of diabetic retinopathy (DR), but it is unclear which NO synthase (NOS) isoforms are primarily involved. In this study, the authors aimed to clarify the involvement of constitutive (eNOS, nNOS) and inducible NOS (iNOS) isoforms and the mechanisms underlying NO-mediated leukostasis and BRB breakdown. METHODS. Diabetes was induced with streptozotocin for 2 weeks. Mice were treated with a NOS inhibitor, N G -nitro-Larginine methyl ester (L-NAME), which shows a preference for constitutive isoforms over iNOS. Vessel leakage was assessed with Evans blue. Leukostasis was quantified in flat-mounted retinas with confocal microscopy, in vivo with a scanning laser ophthalmoscope, and in vitro in a retinal endothelial cell line. ICAM-1, occludin, and ZO-1 levels were assessed by Western blot, flow cytometry, or immunohistochemistry. Nitrotyrosine content was assessed by immunohistochemistry. RESULTS. Diabetes increased leukostasis within retinal vessels and BRB permeability, which were reduced by L-NAME. Similar effects were observed in diabetic iNOS knockout mice. In diabetic mouse retinas, ICAM-1 protein levels increased, whereas the immunoreactivity of tight junction proteins, occludin and ZO-1 decreased, in correlation with increased protein levels of all NOS isoforms. Those effects were prevented by L-NAME and also in diabetic iNOS knockout mice. High glucose and nitrosative/oxidative stress also increased leukostasis caused by ICAM-1 upregulation. CONCLUSIONS. These results indicate that the iNOS isoform plays a predominant role in leukostasis and BRB breakdown. The mechanism involves ICAM-1 upregulation and tight junction protein downregulation. (Invest Ophthalmol Vis Sci. 2007;48: 5257‐5265) DOI:10.1167/iovs.07-0112
TL;DR: In this article, the electrodynamics of metamaterials that consist of resonant non-magnetic inclusions embedded in an epsilon-near-zero (ENZ) host medium are studied and analyzed in detail.
Abstract: In this work, we study the electrodynamics of metamaterials that consist of resonant non-magnetic inclusions embedded in an epsilon-near-zero (ENZ) host medium. It is shown that the inclusions can be designed in such a way that both the effective permittivity and permeability of the composite structure are simultaneously zero. Two different metamaterial configurations are studied and analyzed in detail. For a particular class of problems, it is analytically proven that such matched zero-index metamaterials may help improving the transmission through a waveguide bend, and that the scattering parameters may be completely independent of the specific arrangement of the inclusions and of the granularity of the crystal. The proposed concepts are numerically demonstrated at microwaves with a metamaterial realistic realization based on an artificial plasma.
TL;DR: In this paper, the authors developed a self-consistent approach to homogenize arbitrary nonmagnetic periodic metamaterials, which can fully characterize the effects of frequency dispersion, magnetoelectric coupling, and spatial dispersion even in frequency band gaps or when the materials are lossy.
Abstract: In this work, we develop a systematic and self-consistent approach to homogenize arbitrary nonmagnetic periodic metamaterials. The proposed method does not rely on the solution of an eigenvalue problem and can fully characterize the effects of frequency dispersion, magnetoelectric coupling, and spatial dispersion, even in frequency band gaps or when the materials are lossy. We formulate a homogenization problem to characterize a generic microstructured artificial material, and demonstrate that it is equivalent to an integral-differential system. We prove that this complex system can be reduced to a standard integral equation and solved using standard methods. To illustrate the application of the proposed method, we homogenize several important metamaterial configurations involving split-ring resonators and metallic wires.
TL;DR: In this paper, the authors compared in-person interviews with web-based surveys regarding response rate, information additivity effects and respondents' attitudes towards paying, and concluded in favor of the use of web based surveys.
TL;DR: It is demonstrated, analytically and numerically, that it is possible to design metamaterial cloaks that significantly reduce the total scattering cross section of a given two-dimensional dielectric obstacle in some frequency band.
Abstract: In this work, we assess theoretically the physical response of metamaterial composite structures that emulate the behavior of negative-permittivity materials in certain relevant setups. The metamaterials under analysis consist of metallic parallel-plate implants embedded in a dielectric host in a two-dimensional geometry. Simple design rules and formulas are presented, fully considering the effect and consequences of excitation of higher-order diffraction modes at the metamaterial-dielectric interface. Following the ideas of transparency and cloaking developed by us [Al\`u and Engheta, Phys. Rev. E 72, 016623 (2005)], we demonstrate, analytically and numerically, that it is possible in this way to design metamaterial cloaks that significantly reduce the total scattering cross section of a given two-dimensional dielectric obstacle in some frequency band. This effect, which may be realized in a feasible way, may find interesting applications in electromagnetic cloaking, total scattering cross section reduction, and noninvasive probing.
TL;DR: In this paper, the roughness profile of the substrate surface was obtained with digital image processing and several roughness parameters were assessed based on this profile and were correlated with the corresponding bond strength, both in shear and in tension.