MASS CONSERVATION ENHANCEMENT OF FREE BOUNDARY FLOWS IN COMPOSITES MANUFACTURING

Undesirable void formation during the injection phase of the liquid composite molding process can be understood as a consequence of the non-uniformity of the flow front progression, caused by the dual porosity of the fiber perform. Therefore the best examination of the void formation physics can be provided by a mesolevel analysis, where the characteristic dimension is given by the fiber tow diameter. In mesolevel analysis, liquid impregnation along two different scales; inside fiber tows and within the spaces between them; must be considered and the coupling between these flow regimes must be addressed. In such case, it is extremely important to account correctly for the surface tension effects, which can be modeled as capillary pressure applied at the flow front. When continues Galerkin method is used, exploiting elements with velocity components and pressure as nodal variables, strong numerical implementation of such boundary conditions leads to ill-posing of the problem, in terms of the weak classical as well as stabilized formulation. As a consequence, there is an error in mass conservation accumulated especially along the free flow front. This article presents a numerical procedure, which was formulated and implemented in the existing Free Boundary Program in order to significantly reduce this error.

Mass Conservation Enhancement of Free Boundary Mesolevel Flows during LCM Processes of Composites Manufacturing

Undesirable void formation during the injection phase of the liquid composite moulding process can be understood as a consequence of the non-uniformity of the flow front progression, caused by the dual porosity of the fibre perform. Therefore the best examination of the void formation physics can be provided by a mesolevel analysis, where the characteristic dimension is given by the fibre tow diameter. In mesolevel analysis, liquid impregnation along two different scales; inside fibre tows and within the open spaces between them; must be considered and the coupling between these flow regimes must be addressed. In such case, it is extremely important to account correctly for the surface tension effects, which can be modelled as capillary pressure applied at the flow front. Numerical implementation of such boundary conditions leads to ill-posing of the problem, in terms of the weak classical as well as stabilized formulation. As a consequence, there is an error in mass conservation accumulated especially along the free flow front. This contribution presents a numerical procedure, which was formulated and implemented in the existing Free Boundary Program in order to significantly reduce this error.

Numerical Method to Predict Void Formation during The Liquid Composite Molding Process

Void formation during the injection phase of the liquid composite molding process can be explained as a consequence of the non-uniformity of the flow front progression. This is due to the dual porosity within the fiber perform (spacing between the fiber tows is much larger than between the fibers within in a tow) and therefore the best explanation can be provided by a mesolevel analysis, where the characteristic dimension is given by the fiber tow diameter of the order of millimeters. In mesolevel analysis, liquid impregnation along two different scales; inside fiber tows and within the open spaces between the fiber tows must be considered and the coupling between the flow regimes must be addressed. In such cases, it is extremely important to account correctly for the surface tension effects, which can be modeled as capillary pressure applied at the flow front. Numerical implementation of such boundary conditions leads to illposing of the problem, in terms of the weak classical as well as stabilized formulation. As a consequence, there is an error in mass conservation accumulated especially along the free flow front. A numerical procedure was formulated and is implemented in an existing Free Boundary Program to reduce this error significantly.

The role of ribonuclease R in bacterial adaptation to cold shock

RESUMO:Os microrganismos reagem à súbita descida de temperatura através de uma resposta adaptativa específica que assegura a sua sobrevivência em condições desfavoráveis. Esta adaptação inclui alterações na composição da membrana, na maquinaria de tradução e transcrição. A resposta ao choque térmico pelo frio induz uma repressão da transcrição. No entanto, a descida de temperatura induz a produção de um grupo de proteínas específicas que ajudam a ajustar/re-ajustar o metabolismo celular às novas condições ambientais. Em E. coli o processo de adaptação demora apenas quatro horas, no qual um grupo de proteínas específicas são induzidas. Depois desde período recomeça lentamente a produção de proteínas.A ribonuclease R, uma das proteínas induzidas durante o choque térmico pelo frio, é uma das principais ribonucleases em E. coli envolvidas na degradação do RNA. É uma exoribonuclease que degrada RNA de cadeia dupla, possui funções importantes na maturação e “turnover” do RNA, libertação de ribossomas e controlo de qualidade de proteínas e RNAs. O nível celular desta enzima aumenta até dez vezes após exposição ao frio e estabiliza em células na fase estacionária. A capacidade de degradar RNA de dupla cadeia é importante a baixas temperaturas quando as estruturas de RNA estão mais estáveis. No entanto, este mecanismo é desconhecido. Embora a resposta específica ao “cold shock” tenha sido descoberta há mais de duas décadas e o número de proteínas envolvidas sugerirem que esta adaptação é rápida e simples, continuamos longe de compreender este processo. No nosso trabalho pretendemos descobrir proteínas que interactuem com a RNase R em condições ambientais diferentes através do método “TAP-tag” e espectrometria de massa. A informação obtida pode ser utilizada para deduzir algumas das novas funções da RNase R durante a adaptação bacteriana ao frio e durante a fase estacionária. Mais importante ainda, RNase R poderá ser recrutada para um complexo de proteínas de elevado peso molecular durante o “cold-shock”.------------ABSTRACT:Microorganisms react to the rapid temperature downshift with a specific adaptative response that ensures their survival in unfavorable conditions. Adaptation includes changes in membrane composition, in translation and transcription machinery. Cold shock response leads to overall repression of translation. However, temperature downshift induces production of a set of specific proteins that help to tune cell metabolism and readjust it to the new environmental conditions. For Escherichia coli the adaptation process takes only about four hours with a relatively small set of specifically induced proteins involved. After this time, protein production resumes, although at a slower rate. One of the cold inducible proteins is RNase R, one of the main E. coli ribonucleases involved in RNA degradation. RNase R is an exoribonuclease that digest double stranded RNA, serves important functions in RNA maturation and turnover, release of stalled ribosomes by trans-translation, and RNA and protein quality control. The level of this enzyme increases about ten-fold after cold induction, and it is also stabilised in cells growing in stationary phase. The RNase R ability to digest structured RNA is important at low temperatures where RNA structures are stabilized but the exact role of this mechanism remains unclear. Although specific bacterial cold shock response was discovered over two decades ago and the number of proteins involved suggests that this adaptation is fast and simple, we are still far from understanding this process. In our work we aimed to discover the proteins interacting with RNase R in different environmental conditions using TAP tag method and mass spectrometry analysis. The information obtained can be used to deduce some of the new functions of RNase R during adaptation of bacteria to cold and in stationary growth phase. Most importantly RNase R can be recruited into a high molecular mass complex of protein in cold shock.

Análise da estrutura e da função da proteína morfogenética RodZ de Bacillus subtilis

Resumo: RodZ é um componente do sistema morfogenético das células bacterianas. É uma proteína transmembranar que localiza em bandas ao longo do eixo longitudinal da célula. Em Bacillus subtilis, RodZ consiste numa porção citoplasmática, RodZn, e em uma parte extra-citoplasmática, RodZc. RodZn contém um domínio em helixturn- helix (HTH), enquanto que RodZc pode ser dividido num domínio coiled-coil e num domínio terminal C, de função desconhecida. Um segmento transmembranar (TM) único separa RodZn de RodZc. A eliminação de rodZ causa alongamento do nucleóide e leva à produção de células polares nucleadas. Aqui, mostramos que RodZn é estruturado, estável e em hélice α. Descobrimos que as substituições Y32A e L33A na suposta hélice de reconhecimento (3) do motivo HTH, bem como as substituições Y49A e F53A, fora do motivo HTH (4), causam divisão assimétrica, mas apenas as últimas levam à deslocalização sub-celular de RodZ. Sugerimos que as hélices 3 e 4 são utilizadas para uma interacção proteína-proteína ou proteína- DNA essencial para divisão celular enquanto que 4 deve contactar um componente do citosqueleto, possivelmente MreB, uma vez que a correcta localização sub-celular de RodZ depende desta proteína. Em todos os mutantes as células polares são anucleadas, pelo que concluímos que o alongamento do nucleóide não é um prérequisito para divisão assimétrica. RodZc é largamente não estruturado mas com conteúdo de folha , sendo estabilizado pelo domínio coiled-coil. Mostramos uma relação homóloga entre RodZc e a bomba de transporte Na+/Ca2+ NCX1 e identificámos dois resíduos no domínio C, G265 e N275, essenciais para a manutenção da forma celular. Estes resíduos fazem parte de um motivo em gancho que pode actuar como um local de interacção com um ligando desconhecido. RodZn e RodZc são monoméricos em solução. Contudo, na membrana, RodZ interage consigo própria num sistema de dois híbridos (Split-Ubiquitin) em levedura, sugerindo que possa formar multímeros in vivo.-----------ABSTRACT: RodZ is a transmembrane component of the bacterial core morphogenic apparatus. RodZ localizes in bands long the longitudinal axis of the cell, and it is though to functionally link the cell wall to the actin cytoskeleton. In Bacillus subtilis, RodZ consists of a cytoplasmic moiety, RodZn, and an extracytoplasmic moiety, RodZc. RodZn contains a predicted helix-turn-helix domain, whereas RodZc is thought to contain a coiled-coil region and a terminal C domain of unknown function. A single transmembrane domain separates RodZn from RodZc. Deletion of rodZ causes elongation of the nucleoid and leads to the production of polar minicells containing DNA. Here, we have studied the structure and function of RodZn and RodZc. We show that RodZn is a stable, folded, -helical domain. We discovered that the Y32A and L33A substitutions within the presumptive recognition helix (3) of the HTH motif, as well as the Y49A and F53A substitutions outside of the HTH motif (in 4) cause asymmetric cell division. However, only the substitutions in 4 cause sub-celular delocalization of RodZ. We suggest that 3 and 4 are used for a protein-protein or protein-DNA interaction important for cell division, whereas 4 is likely to contact a cytoskeletal component, presumably MreB. The polar cells formed by all the mutants are anucleate. We conclude that nucleoid elongation is not a prerequisite for asymmetric division. RodZc appears to be a largely unstructured domain, with some -sheet content, and is stabilized by the coiled-coil region. We show a homology relationship between RodZc and the NCX1 Na+/Ca2+ transporter and we found two residues within the C domain, G265 and N275, that are important for cell shape determination. These residues are predicted to be essential determinants of a claw-like motif, which may act as a binding site for an unknown ligand. Both the isolated RodZn and RodZc proteins are monomeric in solution. However, because full-length RodZ interacts with itself in a split-ubiquitin yeast two-hybrid assay, we suggest that it may dimerize or form higher order multimers in vivo.

The monitoring of rammed earth experimental walls and characterization of rammed earth samples

RESTAPIA 2012 - Int. Conf. on Rammed Earth Conservation, Valencia, 21-23 June 2012

Study on the valorization routes of ashes from thermoelectric power plants working under mono-and co-combustion regimes

Thesis submitted to obtain the Doctoral degree in Energy and Bioenergy

Earth-based mortars for masonry plastering

9th International Masonry Conference 2014, 7-9 July, Universidade do Minho, Guimarães

Undrestanding postoperative cognitive dysfunction: novel insights

ABSTRACT: Background: Sleep is integral to biological function and sleep disruption can result in both physiological and psychological dysfunction. The acute cognitive consequences of sleep loss has been an active field of recent investigation, evidence suggests that sleep disruption in critically ill older adults can result in acute decrements in cognitive functioning. Surgery activates the innate immune system, inducing neuroinflammatory changes that interfere with cognition. The fact that patients with sleep disorders have an increased likelihood of exhibiting postoperative delirium encourages us to investigate the contribution of perioperative SF to the neuroinflammatory and cognitive responses of surgery. Methods: The effects of 24h sleep fragmentation (SF) and surgery were explored on adult C57BL/6J male mice. SF procedure started at 7 am with the home-cages being placed on a large platform orbital shaker cycled every 120 seconds (30 sec on/90 sec off). This procedure lasted for 24h. Stabilized tibia fracture was performed either before or after the 24h SF procedure. Separate cohorts of mice were tested for systemic and hippocampal inflammation and cognition. Results: Twenty-four hours of SF induced non-hippocampal memory dysfunction and increase in systemic IL-6. SF and surgery caused hippocampal-dependent memory impairment, although memory impairment was not exacerbated by combining SF with surgery. One day after either SF or surgery there was a significant increase in IL6 mRNA and TNF-alpha mRNA. These increments were more pronounced when either pre or post operative SF was combined with surgery. Conclusions: We show that while SF and surgery can independently produce significant memory impairment, perioperative SF significantly increased hippocampal inflammation without further cognitive impairment. The dissociation between neuroinflammation and cognitive decline may relate to our use of a sole memory paradigm that does not capture other aspects of cognition, especially learning.

PRACTICING ANTHROPOLOGY IN PORTUGAL

The rise of anthropology in Portugal is examined within the framework of several cycles of development. The chapter discusses how the consolidation of anthropology at university level was the main focus until the 90’s. Applied anthropology, as distinctive from academic anthropology received very little attention. Consequently, there was an absence of an institutionalization of applied anthropology in the country. Nowadays, however, two main trends converge that supports the growth of applied anthropology and is providing work for anthropologists outside academia. First, anthropology departments in Portugal have stabilized their staff quotas resulting in very few positions open for anthropologists at the university level. Second, global changes are impacting the social framework of the country and, consequently, opening up new horizons of research and practice for social scientists. Several examples of these opportunities are discussed which is creating an optimism about the various niches for new and relevant anthropological practices.

On an organizational level: How can the emergency department at Rouge Valley Centenary hospital improve their wait times?

The prolonged wait times may arguably put into question the Canadian Health Act of 1984. Statistics show throughput wait times are 5.5 hours and output wait times for admitted patients are 32.4 hours. After probing and analyzing best practices through a qualitative/quantitative Value Stream Mapping and a qualitative SWOT Analysis; Team Triage and an Overcapacity Protocol is suggested to improve non-admitted patients wait times by 1.89 hours and admitted patients wait times by 16 hours by eliminating wasteful steps in the patient process and upon overcapacity, effectively sharing already stabilized and admitted patients with all wards in the hospital.

Engineered MRI nanoprobes based on superparamagnetic iron oxide nanoparticles

This project aimed to engineer new T2 MRI contrast agents for cell labeling based on formulations containing monodisperse iron oxide magnetic nanoparticles (MNP) coated with natural and synthetic polymers. Monodisperse MNP capped with hydrophobic ligands were synthesized by a thermal decomposition method, and further stabilized in aqueous media with citric acid or meso-2,3-dimercaptosuccinic acid (DMSA) through a ligand exchange reaction. Hydrophilic MNP-DMSA, with optimal hydrodynamic size distribution, colloidal stability and magnetic properties, were used for further functionalization with different coating materials. A covalent coupling strategy was devised to bind the biopolymer gum Arabic (GA) onto MNPDMSA and produce an efficient contrast agent, which enhanced cellular uptake in human colorectal carcinoma cells (HCT116 cell line) compared to uncoated MNP-DMSA. A similar protocol was employed to coat MNP-DMSA with a novel biopolymer produced by a biotechnological process, the exopolysaccharide (EPS) Fucopol. Similar to MNP-DMSA-GA, MNP-DMSA-EPS improved cellular uptake in HCT116 cells compared to MNP-DMSA. However, MNP-DMSA-EPS were particularly efficient towards the neural stem/progenitor cell line ReNcell VM, for which a better iron dose-dependent MRI contrast enhancement was obtained at low iron concentrations and short incubation times. A combination of synthetic and biological coating materials was also explored in this project, to design a dynamic tumortargeting nanoprobe activated by the acidic pH of tumors. The pH-dependent affinity pair neutravidin/iminobiotin, was combined in a multilayer architecture with the synthetic polymers poy-L-lysine and poly(ethylene glycol) and yielded an efficient MRI nanoprobe with ability to distinguish cells cultured in acidic pH conditions form cells cultured in physiological pH conditions.