Browsing by Issue Date, starting with "2016-04"
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- Suppressed glycolytic metabolism in the prostate of transgenic rats overexpressing calcium-binding protein regucalcin underpins reduced cell proliferationPublication . Vaz, CV; Marques, Ricardo; Cardoso, HJ; Baptista, Cláudio; Socorro, SílviaRegucalcin (RGN) is a calcium-binding protein underexpressed in human prostate cancer cases, and it has been associated with the suppression of cell proliferation and the regulation of several metabolic pathways. On the other hand, it is known that the metabolic reprogramming with augmented glycolytic metabolism and enhanced proliferative capability is a characteristic of prostate cancer cells. The present study investigated the influence of RGN on the glycolytic metabolism of rat prostate by comparing transgenic adult animals overexpressing RGN (Tg-RGN) with their wild-type counterparts. Glucose consumption was significantly decreased in the prostate of Tg-RGN animals relatively to wild-type, and accompanied by the diminished expression of glucose transporter 3 and glycolytic enzyme phosphofructokinase. Also, prostates of Tg-RGN animals displayed lower lactate levels, which resulted from the diminished expression/activity of lactate dehydrogenase. The expression of the monocarboxylate transporter 4 responsible for the export of lactate to the extracellular space was also diminished with RGN overexpression. These results showed the effect of RGN in inhibiting the glycolytic metabolism in rat prostate, which was underpinned by a reduced cell proliferation index. The present findings also suggest that the loss of RGN may predispose to a hyper glycolytic profile and fostered proliferation of prostate cells.
- Effects of a swimming program on infants' heart rate responsePublication . Costa, Mário J.; Barbosa, Tiago M.; Ramos, Alberto Manuel Sousa; Marinho, DanielThe physiological response has been used to characterize or estimate physical demands while exercising. The aim of this study was to analyze the infant's physiological adaptations over an intervention water program. Fourteen infants (36±5.08 months old) were tested before (M1) and 4 months after (M2) a well-designed swimming program aiming to develop aquatic readiness, cognitive behavior and social interaction. The physiological response was assessed based on heart rate measurements (HR, bpm) at a sampling rate of 1 Hz during several basic aquatic motor skills: 1) individual displacement in ventral position (HR@InD); 2) Individual displacement in vertical position (HR@VD); 3) immersion (HR@Im); 4) voluntary underwater displacement (HR@UnD); 5) jump from the deck (HR@JD); 6) jump from the swimming mat (HR@JM); 7) from a swimming slider (HR@Sli). The HR@Im showed the lowest values (~119 bpm) at the end of the program. Main trend was for a HR decreased over time (HR@Im: -14.17±17.76%; HR@InD: -8.16±9.16%; HR@JD: -10.36±12.70%; HR@Sli: -3.48±6.40%. In all other skills, HR remained unchanged. Our findings suggest that infants experience significant hear rate adaptations while participating on a swimming program. The HR decreases suggests a higher capability to perform the basic aquatic motor skills and a less stressful behavior through the lessons.
- Advances in time course extracellular production of human pre-miR-29b from Rhodovulum sulfidophilumPublication . Pereira, Patrícia; Pedro, Augusto; Tomás, Joana; Baptista, Cláudio; Queiroz, João; Figueiras, Ana; Sousa, FaniThe present study reports the successful production of human pre-miR-29b both intra- and extracellularly in the marine phototrophic bacterium Rhodovulum sulfidophilum using recombinant RNA technology. In a first stage, the optimal transformation conditions (0.025 μg of plasmid DNA, with a heat-shock of 2 min at 35 °C) were established, in order to transfer the pre-miR-29b encoding plasmid to R. sulfidophilum host. Furthermore, the extracellular recovery of this RNA product from the culture medium was greatly improved, achieving quantities that are compatible with the majority of applications, namely for in vitro or in vivo studies. Using this system, the extracellular human pre-miR-29b concentration was approximately 182 μg/L, after 40 h of bacterial growth, and the total intracellular pre-miR-29b was of about 358 μg/L, at 32 h. At the end of the fermentation, it was verified that almost 87 % of cells were viable, indicating that cell lysis is minimized and that the extracellular medium is not highly contaminated with the host intracellular ribonucleases (RNases) and endotoxins, which is a critical parameter to guarantee the microRNA (miRNA) integrity. These findings demonstrate that pre-miRNAs can be produced by recombinant RNA technology, offering novel clues for the production of natural pre-miRNA agents for functional studies and RNA interference (RNAi)-based therapeutics.
- Atividades de inovação em curso ou abandonadas: fatores determinantes nas empresas portuguesasPublication . Duarte, Filipe Alexandre Pereira; Madeira, Maria José AguilarCada vez mais, os mercados, quer a nível nacional, quer a nível internacional, são mais exigentes. A concorrência agressiva e a elevada exigência por parte dos consumidores, fruto de uma globalização e de um fácil acesso à informação, despoletam desafios cada vez maiores às empresas, obrigando-as a uma inovação constante dos seus produtos e serviços para poderem fazer face às necessidades que a atual competitividade empresarial obriga, numa constante busca pela diferenciação com as empresas concorrentes. A presente investigação tem como objetivo analisar os principais determinantes que levam as empresas portuguesas a manterem em curso ou a abandonarem as suas atividades de inovação. Desta forma, a presente investigação foi desenvolvida com base num quadro teórico de diversas abordagens sobre inovação, relacionadas com o Investimento em atividades de I&D, as Barreiras e a Cooperação no âmbito da inovação, corroborado por um suporte empírico, que permitiu identificar e analisar as atividades de inovação, os fatores e as fontes de informação provenientes de várias formas de cooperação, que levam ao abandono ou à manutenção das atividades de inovação em curso. Testaram-se as hipóteses formuladas com os dados secundários obtidos através do Inquérito Comunitário à Inovação – Community Innovation Survey (CIS 2010), que é disponibilizado através do GPEARI/MCTES – Gabinete de Planeamento, Estratégia, Avaliação e Relações Internacionais/Ministério da ciência, Tecnologia e Ensino Superior, referente ao período compreendido entre os anos de 2008 e 2010. A nível estatístico, o método de teste utilizado foi o modelo de regressão logística, onde foi possível analisar as relações existentes entre as diversas variáveis que se apresentaram. De uma forma genérica, os resultados obtidos demonstram que existe uma relação forte entre os determinantes em estudo, com as atividades de inovação que as empresas desenvolvem e que levam à tomada de decisão por parte das mesmas em manterem em curso os seus projetos ou de os abandonarem. Observou-se, assim, que as empresas que apostam num forte investimento em atividades de I&D realizadas dentro das empresas; que identificam e superam barreiras como custos com a inovação demasiado elevados; bem como recorrem a fatores de cooperação como as fontes de informação dentro da própria empresa ou do grupo a que esta pertence; conseguem manter em curso as suas atividades de inovação, não necessitando de as abandonar, tornando-se assim empresas mais competitivas e dessa forma possibilitando o crescimento das mesmas e responder cabalmente às exigências dos mercados.
- Freitas, Manuel Barbosa da CostaPublication . Rosa, José Maria SilvaA visão franciscana da vida, nos seus rasgos de pobreza e amor à verdade, bem assim de uma generosa atenção à existência encarnada, é, porventura, o traço de continuidade mais profundo entre o pensamento e a ação de M. B. C. F. Entrando ainda jovem na Ordem Franciscana, essa visão aprofundou-se em liberdade e razões, marcando decisivamente o seu modo de relação com a realidade.
- Effective models of inflation from a non-local frameworkPublication . Koshelev, Alexey; Kumar, K. Sravan; Moniz, PauloThe dilaton is a possible inflaton candidate following recent CMB data allowing a non-minimal coupling to the Ricci curvature scalar in the early Universe. In this paper, we introduce an approach that has seldom been used in the literature, namely dilaton inflation with non-local features. More concretely, employing non-local features expressed in J. High Energy Phys. 04 (2007) 029, we study quadratic variations around a de Sitter geometry of an effective action with a non-local dilaton. The non-locality refers to an infinite derivative kinetic term involving the operator $\mathcal{F}\left(\Box\right)$. Algebraic roots of the characteristic equation $\mathcal{F}(z)=0$ play a crucial role in determining the properties of the theory. We subsequently study the cases when $\mathcal{F}\left(\Box\right)$ has one real root and one complex root, from which we retrieve two concrete effective models of inflation. In the first case we retrieve a class of single field inflations with universal prediction of $n_{s}\sim0.967$ with any value of the tensor to scalar ratio $r<0.1$ intrinsically controlled by the root of the characteristic equation. The second case involves a new class of two field conformally invariant models with a peculiar quadratic cross-product of scalar fields. In this latter case, we obtain Starobinsky like inflation through a spontaneously broken conformal invariance. Furthermore, an uplifted minimum of the potential, which accounts for the vacuum energy after inflation is produced naturally through this mechanism intrinsically within our approach.
- Functionalization and photocuring of an L-lactic acid macromer for biomedical applicationsPublication . Marques, Dina; Santos, João; Ferreira, Paula; Correia, Tiago R.; Correia, Ilídio Joaquim Sobreira; Gil, Maria; Baptista, Cristina Maria dos Santos GaudêncioL-lactic acid was the starting material for obtaining bioahesives. Reaction with 1,4-butanediol provided a telechelic lactic acid prepolymer with hydroxyl end groups further functionalized with 2-isocyanatoethyl methacrylate. Films were produced upon UV irradiation, 2 min, after addition of Irgacure 2959. This was a solvent and catalyst free process. Thermal characterization of films confirmed stability at physiological temperature, enabling photocuring. Adhesion properties were assessed with good results. In vitro degradation tests showed moderate hydrolytic instability dependent on thickness. SEM images revealed a uniform and compact structure. Thrombosis tests confirmed the materials’ thrombogenicity while biocompatibility experiments showed fibroblast viability and antimicrobial behavior.
- Classical and quantum cosmology of the little rip abrupt eventPublication . Albarran, Imanol; Bouhmadi Lopez, Mariam; Kiefer, Claus; Marto, João; Moniz, PauloWe analyze from a classical and quantum point of view the behavior of the universe close to a little rip, which can be interpreted as a big rip sent towards the infinite future. Like a big rip singularity, a little rip implies the destruction of all bounded structure in the Universe and is thus an event where quantum effects could be important. We present here a new phantom scalar field model for the little rip. The quantum analysis is performed in quantum geometrodynamics, with the Wheeler-DeWitt equation as its central equation. We find that the little rip can be avoided in the sense of the DeWitt criterion, that is, by having a vanishing wave function at the place of the little rip. Therefore our analysis completes the answer to the question: can quantum cosmology smoothen or avoid the divergent behavior genuinely caused by phantom matter? We show that this can indeed happen for the little rip, similar to the avoidance of a big rip and a little sibling of the big rip.