Browsing by Issue Date, starting with "2016-08"
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- Netativismo e indignação na esfera públicaPublication . Correia, João CarlosUma das consequências da aparição da sociedade em rede foi a diferenciação estrutural introduzida na noção de espaço público,verificada peloimpacto das redes sociais num ambiente comunicativo caracterizado pela aceleração significativa das trocas simbólicas, induzidas pelos meios digitais, nomeadamente redes sociais e comunicações móveis.Uma das características centrais desta diferenciação é a apropriação de modelos de comunicação alargada, desenvolvidos pelas redes sociais. Estes modelos de comunicação por um lado são potenciadores da construção, partilha e vivência alargada de experiências colaborativas. Por outro lado, refletem redes informais de comunicação que convergem num novo modelo de configuração hegemónica. Assim traduzem modelos contraditórios de globalização. Qual é a qualidade do discurso público e em que medida traduz um ganho epistêmico resultante do exercício dos modelos de comunicação colaborativa em rede? Que efeitos na comunicação pública são suscetíveis de serem identificados nos novíssimos movimentos sociais? Qual o significado do diálogo público nas novas condições de interação geradas por novos dispositivos e plataforma? De que forma as trocas simbólicas na rede expressam na sua materialidade a reconfiguração das estruturas do espaço público e da ação política? Qual o papel da literacia digital napossível reconfiguração destes modelos comunicativos?Tendo em conta as manifestações portuguesas de indignados contra a austeridade, questionamos o impacto dos media digitais no mundo da vida e na esfera publica onlineem tempos marcados por umacomunicação cada vez mais móvel. Segundo o ponto de vista adotado, a comunicação onlinee o desmpenho do utilizador num ambiente móvel produziram uma vasta quantidade de possibilidades relacionadas com a configuração da ação coletiva no espaço público que reflectem as vicissitudes induzidas pela nova ecologia mediática.
- O Rex PacificusPublication . Rosa, José Maria SilvaNão se sabe exatamente quem, no princípio de 1302, escreveu a Questão intitulada Acerca do Poder do Papa [Quaestio de Potestate Papae], mais conhecido pelo seu incipit: Rex Pacificus. A ideia de uma autoria a várias mãos, alvitrada por alguns especialistas, apesar de tentadora, parece-nos ser de descartar por razões que decorrem do próprio estilo da escrita, na qual a presença de um autor é amiúde marcada pela primeira pessoa do singular: dico, et hoc dico, dico quod non, dico quod falsum est, etc.. Poderíamos admitir que o autor fosse o dominicano João Quidort de Paris,...
- Nano‐in‐Micro POxylated Polyurea Dendrimers and Chitosan Dry Powder Formulations for Pulmonary DeliveryPublication . Restani, Rita; Silva, A. Sofia; Pires, Rita; Cabral, Renato; Correia, Ilídio Joaquim Sobreira; Casimiro, Teresa; Bonifácio, Vasco; Ricardo, Ana AguiarPulmonary administration offers excellent advantages over conventional drug delivery routes, including increasing therapeutics bioavailability, and avoiding long‐term safety issues. Formulations of nano‐in‐micro dry powders for lung delivery are engineered using (S)‐ibuprofen as a model drug. These biodegradable formulations comprise nanoparticles of drug‐loaded POxylated polyurea dendrimers coated with chitosan using supercritical‐fluid‐assisted spray drying. The formulations are characterized in terms of morphology, particle‐size distribution, in vitro aerodynamic particle pulmonary distribution, and glutathione‐S‐transferase assay. It is demonstrated that ibuprofen‐loaded nanoparticles can be successfully incorporated into microspheres with adequate aerodynamic properties, mass median aerodynamic diameter (1.86–3.83 μm), and fine particle fraction (28%–45%), for deposition into the deep lung. The (S)‐ibuprofen dry powder formulations show enhanced solubility, high swelling behavior and a sustained drug release at physiologic pH. Also, POxylated polyureas decrease the (S)‐ibuprofen toxic effect on cancer cellular growth. The 3‐(4,5‐dimethylthiazol‐2‐yl)‐5‐(3‐carboxymethoxyphenyl)‐2‐(4‐sulfophenyl)‐2H‐tetrazolium (MTS) assays show no significant cytotoxicity on the metabolic activity of human lung adenocarcinoma ephithelial (A549) cell line for the lowest concentration (1 × 10−3 m), even for longer periods of contact with the cells (up to 120 h), and in the normal human dermal fibroblasts cell line the toxic effect is also reduced.
- Trends in diabetes incidence from 1992 to 2015 and projections for 2024: A Portuguese General Practitioner's Network studyPublication . Sousa-Uva, Mafalda de; Antunes, Liliana; Nunes, Baltazar; Rodrigues, Ana Paula; Simões, José Augusto Rodrigues; Ribeiro, R. T.; Boavida, José; Dias, CarlosBackground: Diabetes is known as a major cause of morbidity and mortality worldwide.Portugal is known as the European country with the highest prevalence of this disease.While diabetes prevalence data is updated annually in Portugal, the General Practitioner’s(GP) Sentinel Network represents the only data source on diabetes incidence. This studydescribes the trends in Diabetes incidence, between 1992 and 2015, and estimate projectionsfor the future incidence rates in Portugal until 2024.Methods: An ecological time-series study was conducted using data from GP Sentinel Net-work between 1992 and 2015. Family doctors reported all new cases of Diabetes in theirpatients’ lists. Annual trends were estimated through Poisson regression models as well asthe future incidence rates (until 2024), sex and age group stratified. Incidence rate projec-tions were adjusted to the distribution of the resident Portuguese population given StatisticsPortugal projections.Results: The average increase in Diabetes incidence rate was in total 4.29% (CI95% 3.80–4.80)per year under study. Until 1998–2000, the annual incidence rate was higher in women, andfrom 1998–2000 to 2013–2015 turn out to be higher in men. The incidence rate projected for2022–2024 was 972.77/105inhabitants in total, and 846.74/105and 1114.42/105, respectively,in women and men.Conclusions: This is the first study in Portugal to estimate diabetes incidence rate projections.The disturbing reported projections seem realistic if things continue as in the past. Actually,effective public health policies will need to be undertaken to minimize this alarming futurescenario.
- Uniqueness of the Fock quantization of Dirac fields in 2+1 dimensionsPublication . Cortez, Jerónimo; Elizaga Navascués, Beatriz; Martín-Benito, Mercedes; Mena Marugan, Guillermo A.; Velhinho, JoséWe study the Fock quantization of a free Dirac field in 2+1-dimensional backgrounds which are conformally ultrastatic, with a time-dependent conformal factor. As it is typical for field theories, there is an infinite ambiguity in the Fock representation of the canonical anticommutation relations. Different choices may lead to unitarily inequivalent theories that describe different physics. To remove this ambiguity one usually requires that the vacuum be invariant under the unitary transformations that implement the symmetries of the equations of motion. However, in non-stationary backgrounds, where time translation is not a symmetry transformation, the requirement of vacuum invariance is in general not enough to fix completely the Fock representation. We show that this problem is overcome in the considered scenario by demanding, in addition, a unitarily implementable quantum dynamics. The combined imposition of these conditions selects a unique family of equivalent Fock representations. Moreover, one also obtains an essentially unique splitting of the time variation of the Dirac field into an explicit dependence on the background scale factor and a quantum evolution of the corresponding creation and annihilation operators.
- Quantum cosmology of scalar-tensor theories and self-adjointnessPublication . Almeida, Carla; Batista, António B.; Fabris, Júlio C.; Moniz, PauloIn this paper, the problem of the self-adjointness for the case of a quantum minisuperspace Hamiltonian retrieved from a Brans-Dicke (BD) action is investigated. Our matter content is presented in terms of a perfect fluid, onto which the Schutz's formalism will be applied. We use the von Neumann theorem and the similarity with the Laplacian operator in one of the variables to determine the cases where the Hamiltonian is self-adjoint and if it admits self-adjoint extensions. For the latter, we study which extension is physically more suitable.
- Stimuli-responsive mesoporous silica nanoparticles for cancer therapy: A reviewPublication . Moreira, André; Dias, Diana Rodrigues; Correia, Ilídio Joaquim SobreiraThe application of nanocarriers as selective drug delivery platforms, as imaging or as diagnostic agents has been evaluated in several studies in the area of biomedicine, namely for cancer therapy. Such systems have the potential to perform a controlled and site-specific delivery of therapeutic agents leading to a reduction of side effects and, ultimately, to an improved therapeutic outcome. Among the different nanocarriers developed so far, mesoporous silica nanoparticles have attracted the attention of the scientific community for being applied as drug delivery systems that are capable of controlling, both in space and time, the drug release. In this review, the modifications performed, so far, on mesoporous silica nanoparticles to imprint them a stimulus responsive behavior (namely, pH, redox potential, adenosine triphosphate, enzyme or temperature) in order to allow their application in cancer therapy are highlighted.