The Exploitation of Host Iron Sources by Candida albicans during Oral Infection

Tight binding of iron by host proteins provides a natural resistance to microbial infections described as “nutritional immunity”. Inside oral epithelial cells, iron is stored in ferritin. The aim of this study was to determine the natural iron sources for the human pathogenic fungus Candida albicans during oral infection. In vitro, C. albicans can grow at physiological pH with ferritin as the sole source of iron while the baker’s yeast Saccharomyces cerevisiae cannot. Moreover, C. albicans is only able to use ferritin as an iron source under conditions which permit acid production and acidification of the surrounding environment. A screen of mutants lacking components of each of the three iron acquisition systems of C. albicans revealed that only the reductive pathway is involved in ferritin iron utilisation. Additionally, hyphae but not yeast cells of this fungus can bind ferritin and this binding is essential for iron acquisition from ferritin. Transcriptional analysis of C. albicans cells binding ferritin suggested a role for the hyphal-associated protein Als3p in binding of ferritin. Indeed, hyphae of a mutant lacking Als3p were unable to bind ferritin. Furthermore, heterologous expression of Als3p allowed S. cerevisiae to bind ferritin, suggesting that Als3p is a ferritin receptor. Immunofluorescence localisation of ferritin in epithelial cells infected with C. albicans showed ferritin surrounding hyphae from wild type but not Dals3 mutant cells. In summary, this study suggests that C. albicans can use ferritin as an iron source via direct binding by Als3 on the surface of hyphae; iron release is then mediated by acidification and uptake is facilitated by the reductive pathway. This is the first study which demonstrates that a pathogenic microbe can directly use ferritin as an iron source

Design of a real-time hidden markov model state decoding system

Hidden Markov Models are used in different kinds of sequence recognition problems. Specially, Hidden Markov Models are suited for speech/speaker recognition systems. Due to the complexity of the algorithms involved, general-purpose computing solutions are typically significantly slower than real time. For many applications, however, real-time is essential and thus a system based in specific purpose hardware becomes necessary. For the probability computation in pattern recognition systems using Hidden Markov Models, a state decoding system is necessary. The state decoding system must be able to decide, based on the input sequence, which is the most probable state sequence that produces the input sequence and therefore the reference pattern which best matches with the input pattern. In this work, the implementation of a real-time Hidden Markov Model state decoding system is described. The prototype was implemented for left-right Markov Models.Eje: Agentes inteligentesRed de Universidades con Carreras en Informática (RedUNCI

Design of a real-time hidden markov model state decoding system

Hidden Markov Models are used in different kinds of sequence recognition problems. Specially, Hidden Markov Models are suited for speech/speaker recognition systems. Due to the complexity of the algorithms involved, general-purpose computing solutions are typically significantly slower than real time. For many applications, however, real-time is essential and thus a system based in specific purpose hardware becomes necessary. For the probability computation in pattern recognition systems using Hidden Markov Models, a state decoding system is necessary. The state decoding system must be able to decide, based on the input sequence, which is the most probable state sequence that produces the input sequence and therefore the reference pattern which best matches with the input pattern. In this work, the implementation of a real-time Hidden Markov Model state decoding system is described. The prototype was implemented for left-right Markov Models.Eje: Agentes inteligentesRed de Universidades con Carreras en Informática (RedUNCI

Microalgae-bacterial biomass outperforms PN-anammox biomass for oxygen saving in continuous-flow granular reactors facing extremely low-strength freshwater aquaculture streams

The dissolved oxygen (DO) concentration in water streams is one of the most important and critical quality parameters in aquaculture farms. The main objective of this study was to evaluate the potential of two Continuous Flow Granular Reactors, one based on Partial Nitrification-Anammox biomass (Aquammox CFGR) and the other on Microalgae-Bacteria biomass (AquaMab CFGR), for improving dissolved oxygen availability in the recirculation aquaculture systems (RAS). Both reactors treated the extremely low-strength effluents from a freshwater trout farm (1.39 mg NH4 +-N/L and 7.7 mg TOC/L). The Aquammox CFGR, removed up to 68% and 100% of ammonium and nitrite, respectively, but the DO concentration in the effluent was below 1 mg O2/L while the anammox activity was not maintained. In the AquaMab CFGR, bioaugmentation of aerobic granules with microalgae was attained, producing an effluent with DO concentrations up to 9 mg O2/L and removed up to 77% and 80% of ammonium and nitrite, respectively, which is expected to reduce the aeration costs in fish farms.info:eu-repo/semantics/publishedVersio

A unified power converter for solar PV and energy storage in dc microgrids

This paper deals with the development and experimental validation of a unified power converter for application in dc microgrids, contemplating the inclusion of solar photovoltaic (PV) panels and energy storage systems (ESS), namely batteries. Considering the limitations presented by the current structure of the power grid, mostly highlighted by the accentuated integration of emerging technologies (ESS, renewables, electric vehicles, and electrical appliances that natively operate in dc), it is extremely pertinent to adopt new topologies, architectures, and paradigms. In particular, decentralized power systems, unified topologies, and correspondent control algorithms are representative of a new trend towards a reduction in the number of power converters. Thus, the developed solution is designed to operaSAVE-15te at a nominal power of 3.6 kW, with a switching frequency of 100 kHz, and in four operation modes concerning power flow: (i) solar PV panels to batteries (PV2B); (ii) solar PV panels to dc grid (PV2G); (iii) batteries to dc grid (B2G); (iv) dc grid to batteries (G2B). Moreover, a dual active bridge converter guarantees galvanic isolation, while two back-end dc–dc converters are responsible for interfacing solar PV panels and batteries. The experimental validation of the proposed unified power converter proves its application value to self-consumption production units.This work has been supported by FCT—Fundação para a Ciência e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020. This work has been supported by the MEGASOLAR Project POCI-01-0247-FEDER-047220

Educação ambiental e teoria crítica da educação: algumas considerações pertinentes

Apresenta algumas reflexões a respeito da teoria e prática, sobre a atuação de atores sociais que, em diferentes contextos engajaram-se na construção de uma identidade interdisciplinar, e incentivar a inserção da educação ambiental (EA) na educação escolar. Em relação à educação básica, e na perspectiva da inserção da EA na sala de aula, entende-se que todas as áreas do conhecimento assim como todos os seus componentes curriculares apresentam-se ricas em temas ambientais e em espaços ociosos entre os componentes curriculares. Considera-se a possibilidade de utilização desses espaços para a inserção de temas ambientais capazes de proporcionar condições de aprofundamento, contextualização, diversificação de oportunidades de estudos e novas aprendizagens em EA. Sugere-se como ponto de partida, o trabalho interdisciplinar, que envolvam a sala de aula, a escola e a comunidade. No ensino superior a EA ainda não é postulada como componente obrigatório nos currículos dos cursos

Nitrogen removal from freshwater aquaculture effluents: sequencing versus continuous granular sludge reactors

info:eu-repo/semantics/publishedVersio

Granular sludge technology for valorization of water use: from high to low strength effluents in aquaculture

info:eu-repo/semantics/publishedVersio