Starch determination in Chlorella vulgaris-a comparison between acid and enzymatic methods

Different methods for estimating starch in Chlorella vulgaris were compared with the view of establishing a procedure suitable for rapid and accurate determination of starch content in this microalgal species. A close agreement was observed between methods that use perchloric acid and enzymatic methods that use α-amylase and amyloglucosidase to hydrolyze the starch of microalgae grown under different nitrogen culture conditions. Starch values obtained by these methods were significantly higher than those estimated by using hydrochloric acid as solubilizing and hydrolyzing agent. The enzymatic method (EM1) proved to be the most rapid and precise method for microalgal starch quantification. Furthermore, the evaluation of resistant starch by enzymatic methods assayed in nitrogen-sufficient and nitrogen-starved cells showed that no formation of this type of starch occurred in microalgae, meaning that this should not interfere with starch content determinations.This research work was supported by the grants SFRH/BD/44724/2008 (Bruno Fernandes) from Fundacao para a Ciencia e a Tecnologia (Portugal) and SFRH/BPD/44935/2008 (Giuliano Dragone). The authors also acknowledge the financial support received through the projects INNOVALGAE (FCT PTDC/AAC-AMB/108511/2008) and ALGANOL

Valorization of toxic cyanobacteria biomass - disruption efficiency assessment and consequent bioproduct availability using different disruption techniques

The worldwide occurrence of hepatotoxic cyanobacterium Microcystis aeruginosa and accumulation of its toxin microcystin-LR, have been responsible for several human deaths and animal intoxication incidents. In recognition to its toxicity, the World Health Organization and several national governments established guideline values for this toxin in water, which gave rise to an increasing demand for microcystin′s analytical standards. These standards might be useful either as laboratory standards to apply in human and environmental risk assessment or as tools for molecular and cell biology studies. However, their availability is still limited due to constraints found in production and purification processes, which inflate the final price to values as high as 28000 €/mg. As an example of the increasing interest observed over the last years, U.S. Environmental Protection Agency has recently announced that cyanotoxins became part of its list of substances to be studied as a precursor to regulatory action between 2018 and 2020. Consequently, the optimization of this cyanobacterium cultivation and toxin purification techniques is needed to decrease the production cost of such high added-value product. In biotechnological industrial scale processes, the costs associated with downstream processing often represent more than 60 % of the overall expenses. The aim of this work is therefore to provide an insight regarding the development of a costeffective process for obtaining high-quality and affordable microcystin-LR by evaluating the efficiency of three different methodologies (microwave, freeze-thaw cycles and bead mill) on the disruption of M. aeruginosa and consequent availability of bioproducts. For that purpose, several parameters including time, power, and temperature were tested. The best conditions determined for each extraction method were the following: i) 1.5 minutes at 800 W (microwave), ii) three 12- hour cycles at -20 ºC (freeze-thaw cycles), and iii) 7 minutes using 20 % (v/v) of glass beads (bead mill). According to cell counting and intracellular organic matter release determining techniques, freeze-thaw cycles have shown to be the best disruption method presenting an overall efficiency around 97 %

Comparison of harvesting methods for the cyanobacteria Microcystis aeruginosa

BioTech 2017 and 7th Czech-Swiss Symposium with ExhibitionMicrocystis aeruginosa is a wellknown cyanobacterium that has been spreading all over the world due to increased temperatures and eutrophication of water bodies caused by intensive anthropogenic activities. This toxin-producing microorganism is frequently responsible for diminishing water quality and causing intoxication of humans and animals. Due to this, its intracellular cyanotoxin – microcystin (MC) – is commonly used as tool for molecular and cell biology studies or as a standard in human and environmental risk assessment assays. Moreover, MC is a promising anticancer/antitumor drug candidate and a possible antimicrobial, antifungal, antialgal and insecticide agent. Despite MC’s potential application in several biotechnological fields, its high production costs significantly contribute for the prohibitive selling prices (28000 e/mg). Thus, improvements in process’ cost-effectiveness is needed, especially in terms of downstream processing techniques which are probably the major bottlenecks of cyanobacteria production at large scale, commonly representing 20-30 % of the total costs. Bearing this in mind, this study aimed at optimizing harvesting of M. aeruginosa induced by pH change and compares the optimal conditions obtained with the use of three different flocculant agents: chitosan, ferric chloride, and aluminium chloride. Harvesting induced by pH was assessed by testing pH values ranging between 2 and 14. Despite the fact that harvesting efficiencies above 90 % were obtained for most pH values, pH 2 was the one where higher sedimentation rate was observed and consequently the chosen method to compare with the three flocculants. Aluminium chloride addition was found to be the most efficient method, reaching 93 % of sedimentation efficiency within the first 2 h. These results are in agreement with zeta potential measurements where cells presented nearly neutral (approx. 0 mV) charge, while positive or negative charges where achieved using the other three methodologies.This research work was supported by the grant SFRH/BPD/98694/2013 (Bruno Fernandes) and SFRH/BD/52335/2013 (Pedro Geada) from Fundação para a Ciência e a Tecnologia (Portugal). Luís Loureiro is recipient of a fellowship supported by a doctoral advanced training (call NORTE-69-2015-15) funded by the European Social Fund under the scope of Norte2020 - Programa Operacional Regional do Norte. This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684), Project UID/Multi/04423/2013, Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462), FCT Strategic Project of UID/BIO/04469/2013 unit, by the project NOVELMAR (reference NORTE-01-0145-FEDER-000035), co-financed by the North Portugal Regional Operational Programme (Norte 2020) under the National Strategic Reference Framework (NSRF), through the ERDF, and by BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio

Aplicação das ferramentas da qualidade na identificação das avarias relacionadas com a queima de transformadores: estudo de caso realizado em uma empresa de distribuição de energia elétrica no estado de Sergipe

O seguinte artigo tem como principal tema abordado, identificar as razões para as queimas dos transformadores elétricos da empresa Energisa-Sergipe, principal empresa distribuidora de energia elétrica do estado de Sergipe. Para que fosse alcançado o objetivo do estudo, foram utilizadas algumas ferramentas fundamentais da qualidade, como brainstorming, diagrama de causa e efeito, gráfico de Pareto, entre outras. Através do uso destas ferramentas, conseguiu-se identificar quais eram os motivos que ocorriam com mais frequência para as queimas dos transformadores e com isso foi possível aumentar a qualidade do serviço prestado pela empresa e reduzindo consideravelmente os custos relacionados com a aquisição dos transformadores.Salvado

Evaluating contacts in opportunistic networks over more realistic simulation models

Opportunistic Networks (ONs) are mobile networks that support intermittent links and long delays. ON nodes exchange data in brief moments called contacts, when another node is within radio range. Contacts are ephemeral and unpredictable, thus they must be implemented as efficiently as possible. However, most previous work rely on simplistic assumptions such as unlimited bandwidth and contentionfree transmissions. This paper presents a more realistic evaluation of ON contacts. Simulations show that, on opposition to the consensus in the literature, routing protocols that forward more copies and those that determine a subset of nodes to receive the Bundles using a certain criteria outperform flooding-based protocols, because the latter generates too much medium contention. Finally, buffer management and forwarding prioritization may influence the performance of the network by up to 30%.Keywords: Opportunistic networks, simulation, Delay-Tolerant Networks

The AutoI approach for the orchestration of autonomic networks

Existing services require assurable end to-end quality of service, security and reliability constraints. Therefore, the networks involved in the transport of the data must cooperate to satisfy those constraints. In a next generation Internet, each of those networks may be managed by different entities. Fur thermore, their policies and service level agreements (SLAs) will differ, as well as the autonomic management systems controlling them. In this context, we in the Autonomic Internet (AutoI) consortium propose the Orchestration Plane (OP), which promotes the interaction among different Autonomic Management Systems (AMSs). The OP mediates the communication and negotiation amongAMSs, ensuring that their SLAs and policies meet the requirement needed for the provisioning of the services. It also simplifies the federation of domains and the distribution of new services in virtualised network environments.Peer ReviewedPostprint (author’s final draft

atualização em 2023 da Sociedade Portuguesa de Neonatologia. Parte I. Necessidades nutricionais e nutrição entérica durante o internamento

Publisher Copyright: © 2023 Portuguese Society of Pediatrics.Recent evidence-based data motivated this update of the Portuguese Neonatal Society guidelines for the enteral nutrition of infants born preterm. The purpose of this document is to support the clinical practice and was mainly oriented by the updated European Society for Pediatric Gastroenterology Hepatology and Nutrition (ESPGHAN) 2022 position paper, the World Health Organization recommendations 2022, and other reference articles, particularly systematic reviews. These guidelines are published in two parts. Part I addresses the nutrient requirements and the enteral feeding approach during the hospital stay, including optimization of the mother’s own milk feeding and methods for enteral feeding. Part II is directed to particularities of enteral feeding in specific clinical conditions, and feeding after discharge, including breastmilk fortification at home and introduction of complementary feeding.publishersversionpublishe

Modelo para la interoperabilidad entre controladores de redes definidas por software

Software Defined Networking (SDN) o las redes definidas por software, se enfocan en la programación por software de las mismas, en el cual el control se desvincula del hardware. El plano de control es separado de la capa de red física y puede controlar flujos por separado dependiendo de las políticas definidas. El Controlador es una parte importante de la red SDN, que actúa como un cerebro virtual. No sólo puede monitorizar el tráfico de una red con facilidad, sino que le ordena a los sistemas por debajo, como switches, routers y otros equipos de la red, de cómo manejar el tráfico, haciendo una gestión inteligente, cumpliendo con las políticas que se programaron en el mismo. Pero si dos dominios SDN se quisieran comunicar entre sí para distribuir sus políticas, como priorizar paquetes en el caso de video conferencia para mejorar la calidad de servicio, o en el caso de paquetes multimediales a los cuales se les quiera dar mayor prioridad. Los controladores SDN podrían establecer relaciones de confianza unidireccional o bidireccional entre esos paquetes de forma dinámica. Para ello se debería contar con un modelo única para que los diferentes controladores para que puedan comunicarse o Interoperar entre sí.Eje: Ingeniería del Software.Red de Universidades con Carreras en Informátic

Qualidade da governação local em Portugal

Coleção "Estudos da Fundação"Quais são os fatores que determinam a qualidade da governação local e como medi-los? Este estudo propõe-se avaliar a qualidade da governação local nos 308 municípios portugueses, através de um índice multidimensional, composto por 22 indicadores identificados e ponderados por um grupo de peritos e perceber quem são e como interagem os principais atores nas redes de governação local em matéria de desenvolvimento económico