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Search Results: 1 - 10 of 132033 matches for " Margarida V. Caldeira "
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Role of the Proteasome in Excitotoxicity-Induced Cleavage of Glutamic Acid Decarboxylase in Cultured Hippocampal Neurons
Márcio S. Baptista,Carlos V. Melo,Mário Armel?o,Dennis Herrmann,Diogo O. Pimentel,Graciano Leal,Margarida V. Caldeira,Ben A. Bahr,Mário Bengtson,Ramiro D. Almeida,Carlos B. Duarte
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0010139
Abstract: Glutamic acid decarboxylase is responsible for synthesizing GABA, the major inhibitory neurotransmitter, and exists in two isoforms—GAD65 and GAD67. The enzyme is cleaved under excitotoxic conditions, but the mechanisms involved and the functional consequences are not fully elucidated. We found that excitotoxic stimulation of cultured hippocampal neurons with glutamate leads to a time-dependent cleavage of GAD65 and GAD67 in the N-terminal region of the proteins, and decrease the corresponding mRNAs. The cleavage of GAD67 was sensitive to the proteasome inhibitors MG132, YU102 and lactacystin, and was also abrogated by the E1 ubiquitin ligase inhibitor UBEI-41. In contrast, MG132 and UBEI-41 were the only inhibitors tested that showed an effect on GAD65 cleavage. Excitotoxic stimulation with glutamate also increased the amount of GAD captured in experiments where ubiquitinated proteins and their binding partners were isolated. However, no evidences were found for direct GADs ubiquitination in cultured hippocampal neurons, and recombinant GAD65 was not cleaved by purified 20S or 26S proteasome preparations. Since calpains, a group of calcium activated proteases, play a key role in GAD65/67 cleavage under excitotoxic conditions the results suggest that GADs are cleaved after ubiquitination and degradation of an unknown binding partner by the proteasome. The characteristic punctate distribution of GAD65 along neurites of differentiated cultured hippocampal neurons was significantly reduced after excitotoxic injury, and the total GAD activity measured in extracts from the cerebellum or cerebral cortex at 24h postmortem (when there is a partial cleavage of GADs) was also decreased. The results show a role of the UPS in the cleavage of GAD65/67 and point out the deregulation of GADs under excitotoxic conditions, which is likely to affect GABAergic neurotransmission. This is the first time that the UPS has been implicated in the events triggered during excitotoxicity and the first molecular target of the UPS affected in this cell death process.
A espiritualidade nos cuidados de enfermagem: revis?o da divulga??o científica em Portugal
Caldeira,Sílvia; Castelo Branco,Zita; Vieira,Margarida;
Revista de Enfermagem Referência , 2011,
Abstract: context: research and publication, in the international scientific scene, about spirituality and health have been growing since the 90s, particularly in nursing care. objectives: to identify and analyze portuguese scientific publications in nursing, bioethics and health journals, from 1990 to july 2010. method: manual and electronic searches in portuguese nursing journals, bioethics journal and health journal, a total of 21 titles. results: the sample was constituted by 17 papers retrieved from 1217 issues searched. those were: nine concept analysis papers, four research papers, two personal reflection papers and two systematic reviews. the analysis allowed us to categorize spirituality in two dimensions the human dimension of the healthy or ill person and the caring dimension. conclusions: scientific publication about spirituality in nursing care, released in portugal, is represented mostly by reflection papers and theoretical reviews. the quantity of empirical studies is smaller. besides the development of research in this area, it is important that publication is to be accomplished in national journals in order to achieve effective knowledge dissemination.
A espiritualidade nos cuidados de enfermagem: revis o da divulga o científica em Portugal La espiritualidad en los cuidados de enfermería: revisión de la divulgación científica en Portugal Spirituality in nursing care: a review of scientific publication in Portugal
Sílvia Caldeira,Zita Castelo Branco,Margarida Vieira
Revista de Enfermagem Referência , 2011,
Abstract: Contexto: a investiga o e divulga o no panorama científico internacional acerca da espiritualidade e saúde têm vindo a desenhar um movimento crescente desde a década de 90, em particular, nos cuidados de enfermagem. Objetivos: Identificar e analisar a produ o científica publicada em revistas portuguesas de enfermagem, bioética e saúde, desde 1990 até julho de 2010. Método: optou-se pelo método de pesquisa manual e eletrónica nas revistas portuguesas de enfermagem, nos Cadernos de Bioética e nos Cadernos de Saúde, num total de 21 títulos. Resultados: a amostra é constituída por 17 artigos selecionados de 1217 números pesquisados. Nove artigos de revis o de conceitos, quatro artigos de investiga o, dois artigos de reflex o pessoal e duas revis es sistemáticas de literatura. A análise permitiu categorizar a espiritualidade em duas dimens es - dimens o humana da pessoa s ou doente e dimens o do cuidar. Conclus es: a produ o científica sobre a espiritualidade nos cuidados de enfermagem divulgada em Portugal é representada, na sua maioria, por artigos de reflex o e de revis o teórica. é menor o número de estudos empíricos. é importante que, além do desenvolvimento da investiga o nesta área, a sua divulga o seja feita de preferência nas publica es nacionais, para uma efetiva divulga o do conhecimento produzido. Contexto: la investigación y divulgación en el panorama científico internacional acerca de la espiritualidad y de la salud ha desembocado en un movimiento creciente desde la década de 90, en particular, en los cuidados de enfermería. Objetivos: identificar y analizar la producción científica publicada en revistas portuguesas de enfermería, bioética y salud, de 1990 hasta julio del 2010. Método: se optó por el método de pesquisa manual y electrónica en revistas portuguesas de enfermería, en los Cadernos de Bioética y en los Cadernos da Saúde, sumando un total de 21 títulos. Resultados: la muestra está constituida por 17 artículos seleccionados de los 1217 números pesquisados. Nueve artículos de revisión de conceptos, cuatro artículos de investigación, dos artículos de reflexión personal y dos revisiones sistemáticas de la literatura. El análisis permitió categorizar la espiritualidad en dos dimensiones - la dimensión humana de la persona sana o enferma y la dimensión del cuidar. Conclusiones: la producción científica sobre la espiritualidad en los cuidados de enfermería divulgada en Portugal es representada, en su mayoría, por artículos de reflexión y revisión teórica. En menor número se encuentran los estudios empíricos. Es importante que, adem
Role of apoptosis in erosive and reticular oral lichen planus exhibiting variable epithelial thickness
Brant, Juliana M. Caldeira;Vasconcelos, Anilton C.;Rodrigues, Luciana V.;
Brazilian Dental Journal , 2008, DOI: 10.1590/S0103-64402008000300001
Abstract: oral lichen planus (olp) is a chronic inflammatory disease with different clinical types. reticular and erosive forms are the most common. although the cause of olp remains speculative, many findings suggest auto-immune involvement, mediated by t lymphocytes against the basal keratinocytes. inflammation, mechanical trauma or toxic agents can affect the epithelial homeostasia. increased apoptosis may cause a decrease in epithelial thickness reflecting in the activity of the lesion. the objective of this study was to evaluate the occurrence of apoptosis and epithelial thickness in reticular and erosive forms of olp. 15 samples of olp each type (reticular and erosive) plus 10 of healthy mucosa were collected and processed. after morphometry, the apoptotic index and epitelial thickness were obtained. tunel and m30 cytodeath immunohistochemical assay were used to validate the morphologic criteria used. apoptosis in the erosive olp was significantly more intense than in the reticular type and both forms of olp presented more apoptosis than the healthy oral mucosa. healthy oral mucosa was thicker than both olp forms and thicker in olp reticular form than in the erosive one. the clinical differences between reticular and erosive forms of olp are related to variations in epithelial thickness and in intensity of apoptosis.
Dissipative dynamics of topological defects in frustrated Heisenberg spin systems
V. Juricic,L. Benfatto,A. O. Caldeira,C. Morais Smith
Physics , 2004, DOI: 10.1103/PhysRevB.71.064421
Abstract: We study the dynamics of topological defects of a frustrated spin system displaying spiral order. As a starting point we consider the SO(3) nonlinear sigma model to describe long-wavelength fluctuations around the noncollinear spiral state. Besides the usual spin-wave magnetic excitations, the model allows for topologically non-trivial static solutions of the equations of motion, associated with the change of chirality (clockwise or counterclockwise) of the spiral. We consider two types of these topological defects, single vortices and vortex-antivortex pairs, and quantize the corresponding solutions by generalizing the semiclassical approach to a non-Abelian field theory. The use of the collective coordinates allows us to represent the defect as a particle coupled to a bath of harmonic oscillators, which can be integrated out employing the Feynman-Vernon path-integral formalism. The resulting effective action for the defect indicates that its motion is damped due to the scattering by the magnons. We derive a general expression for the damping coefficient of the defect, and evaluate its temperature dependence in both cases, for a single vortex and for a vortex-antivortex pair. Finally, we consider an application of the model for cuprates, where a spiral state has been argued to be realized in the spin-glass regime. By assuming that the defect motion contributes to the dissipative dynamics of the charges, we can compare our results with the measured inverse mobility in a wide range of temperature. The relatively good agreement between our calculations and the experiments confirms the possible relevance of an incommensurate spiral order for lightly doped cuprates.
Majorana Fermions Signatures in Macroscopic Quantum Tunneling
P. L. S. Lopes,V. Shivamoggi,A. O. Caldeira
Physics , 2014,
Abstract: Thermodynamic measurements of magnetic fluxes and I-V characteristics in SQUIDs offer promising paths to the characterization of topological superconducting phases. We consider the problem of macroscopic quantum tunneling in an rf-SQUID in a topological superconducting phase. We show that the topological order shifts the tunneling rates and quantum levels, both in the parity conserving and fluctuating cases. The latter case is argued to actually enhance the signatures in the slowly fluctuating limit, which is expected to take place in the quantum regime of the circuit. In view of recent advances, we also discuss how our results affect a $\pi$-junction loop.
Dynamics of topological defects in a spiral: a scenario for the spin-glass phase of cuprates
V. Juricic,L. Benfatto,A. O. Caldeira,C. Morais Smith
Physics , 2003, DOI: 10.1103/PhysRevLett.92.137202
Abstract: We propose that the dissipative dynamics of topological defects in a spiral state is responsible for the transport properties in the spin-glass phase of cuprates. Using the collective-coordinate method, we show that topological defects are coupled to a bath of magnetic excitations. By integrating out the bath degrees of freedom, we find that the dynamical properties of the topological defects are dissipative. The calculated damping matrix is related to the in-plane resistivity, which exhibits an anisotropy and linear temperature dependence in agreement with experimental data.
Converging Modalities Ground Abstract Categories: The Case of Politics
Ana Rita Farias, Margarida V. Garrido, Gün R. Semin
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0060971
Abstract: Three studies are reported examining the grounding of abstract concepts across two modalities (visual and auditory) and their symbolic representation. A comparison of the outcomes across these studies reveals that the symbolic representation of political concepts and their visual and auditory modalities is convergent. In other words, the spatial relationships between specific instances of the political categories are highly overlapping across the symbolic, visual and auditory modalities. These findings suggest that abstract categories display redundancy across modal and amodal representations, and are multimodal.
Seguran?a pública e seqüestros no Rio de Janeiro 1995-1996
Caldeira, Cesar;
Tempo Social , 1997, DOI: 10.1590/S0103-20701997000100007
Abstract: abduction and detention of a person for ransom (kidnapping), a crime committed generally by gangs, has become a serious problem and challenge to public safety and police action.the high incidence of kidnappings, their dramatic ocurrence and their repercussions on public opinion and image of the city of rio, have made this offense an outstanding point of reference for social and political debate on organized crime. kidnappings have motivated public protests, including in part, the huge demonstration reage rio (a peace march). this paper strives to be contextual. it discusses the public safety policy of the state of rio de janeiro in view of the project of a business-oriented, international city, desired by the entrepreneurial and political elite. it focuses on the rising"law and order" movement and the anti-kipnapping police efforts. finally, it reveals data collected in a on-going research project that attempts to study criminal conduct commonly associated with "organized crime", such as kidnappings, illegal drug trafficking and bank robberies, in order to, eventually, help formulating more effective and democratic public safety policy.
Boron in Wood Preservation: A Review in its Physico-Chemical Aspects
Caldeira,Fernando;
Silva Lusitana , 2010,
Abstract: a review is presented on the application of boron chemicals for the purpose of wood preservation that covers about the past 20 years and mostly the papers published in the journals of the wood science field. topics developed here include the physical phenomena associated with the impregnation of wood with boron-chemical solutions, the issue of preventing leaching and/or fixing boron in wood to lengthen the effect of treatments and/or enable the application of wood and wood products in biodeterioration hazardous conditions, and the chemical and physical effects on wood of a combination of heat and boron treatments. finally, as an essential condition for research aiming at developing more environment friendly and less risky methods for preserving wood with boron chemicals in a efficient way, a survey is made on boron chemistry pertinent to wood preservation.
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