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Liquid mixtures involving fluorinated alcohols: The equation of state (p, r, T, x) of (Ethanol + Trifluoroethanol) Experimental and Simulation

Liquid mixtures involving fluorinated alcohols: The equation of state (p, r, T, x) of (Ethanol + Trifluoroethanol) Experimental and Simulation Pedro Duartea, Djêide Rodriguesa, Marcelo Silvaa, Pedro Morgadoa, Luís Martinsa,b and Eduardo J. M. Filipea* aCentro de Química Estrutural, Instituto Superior Técnico, 1049-001 Lisboa, Portugal bCentro de Química de Évora, Universidade de Évora, 7000-671 Évora, Portugal Fluorinated alcohols are substances with unique properties and high technological value in the pharmaceutical and chemical industries. Trifluoroethanol (TFE), in particular, displays a number of unusual properties as a solvent. For example, it dissolves nylon at room temperature and is effectively used as solvent in bioengineering. The presence of the three fluorines atoms gives the alcohol a high ionization constant, strong hydrogen bonding capability and stability at high temperatures. In the pharmaceutical industry, TFE finds use as the major raw material for the production of inhalation anesthetics. Mixtures of TFE and water (known as Fluorinols®) are used as working fluids for Rankine cycle heat engines for terrestrial and space applications, as a result of a unique combination of physical and thermodynamic properties such as high thermal efficiency and excellent turbine expansion characteristics. Environmentally, TFE is a CFC substitute with an acceptable short lifetime and with small ozone depletion potential. Additionally, TFE is known to induce conformational changes in proteins and it is used as a co-solvent to analyze structural features of partially folded states. The (ethanol + TFE) system displays an interesting and peculiar behaviour, combining a negative azeotrope with high positive excess volumes. In this work, liquid mixtures of (ethanol + TFE) were investigated. The densities of the mixtures were measured as a function of composition between 278K and 338K and at pressures up to 700 bar. The corresponding excess volumes as a function of temperature and pressure, the isothermal compressibilities and thermal expansivities were calculated from the experimental results. The mixtures are highly non-ideal with excess volumes ranging from 0.8 - 1.0 cm3mol-1. Finally, molecular dynamic simulations were performed to model and interpret the experimental results. The Trappe force field was used to simulate the (TFE + ethanol) mixtures and calculate the corresponding excess volumes. The simulation results are able to reproduce the correct sign and order of magnitude of the experimental VE without fitting to the experimental data. Furthermore, the simulations suggest the presence of a particular type of hydrogen bridge between ethanol and TFE, that can help to rationalize the experimental results

Healthrisk assessment from exposure to trihalomethanes in drinking water

A aplicação de compostos clorados na desinfeção da água pode induzir à formação de subprodutos da desinfeção (SPD) com efeitos carcinogénicos e mutagénicos comprovados. Neste trabalho, apresenta-se uma síntese de um estudo sobre a ocorrência de trihalometanos (THM) na água de abastecimento, realizado nos catorze municípios do distrito de Braga (Portugal), visando a avaliação do risco de cancro (RC) e de efeitos não carcinogénicos (HI) com base na metodologia desenvolvida pela USEPA e IRIS. Num cenário gravoso, correspondente à prevalência da maior concentração de THM detetada no período monitorizado, o indicador RC daria valores superiores ao limite máximo definido como negligenciável, verificando-se ser a ingestão a via de exposição mais relevante. Os resultados obtidos para o indicador HI foram quase sempre inferiores à unidade, indicando um nível de risco aceitável, de acordo com os pressupostos do método utilizado. O uso de indicadores do risco para a saúde constitui uma ferramenta útil quer no apoio à decisão das entidades gestoras de sistemas de abastecimento de água, quer na definição de estratégias e políticas de saúde pública que visem a mitigação deste risco.Chlorination havebroughtenormous benefits to the preservation of public health as a low-cost disinfection method, but it cangenerate severalhalogenated organic compounds,as disinfection by-products (DBP), with potentialand proven carcinogenic and mutagenic effects. This workpresents a synthesis of the study performed in watersupply systems ofthe fourteen municipalities of Braga district (Portugal), aiming at the evaluation of lifetime cancer risk (CRindex),and the risk of non-carcinogenic effects (HI-Hazard Index) fromexposure to THMs, usingamethod proposed by USEPA and IRIS.In a severescenario, corresponding to the prevalence of maximum THMconcentrationoccurred duringthe monitored period, the CR index would achieve valueshigher than the maximum limit defined asnegligible forall these municipalities. The HI indexresultswereoftenlower than one,which is consideredas an acceptable risk level. The use of health risk indicators can be a useful tool both in supporting the decision-making of water supplyutilitiesandin the definition of public health strategies/policies forrisk mitigation in order to increasethe life quality and the wellnessof populations

Chemostratigraphy (TOC, 13C, 18O) around the Pliensbachian/Toarcian boundary in the reference section of Peniche (Lusitanian Basin, Portugal)

This work presents the chemostratigraphy analysis based on total organic carbon (TOC) and the evolution of the carbon and oxygen stable isotopes in the whole rock samples around the Pliensbachian/Toarcian boundary in the Peniche section (uppermost part of Lemede Formation and lowermost part of Cabo Carvoeiro Formation). These are partial results which form part of a group of studies, being processed, that include isotope analyses of 87Sr/86Sr, 18O, 13C and major, minor and trace elements in whole rock and belemnites

Remoção de arsénio em águas para consumo humano

A presença de arsénio nas origens de água para consumo humano é um problema que tem suscitado uma preocupação crescente em termos de saúde pública. A poluição por arsénio das águas naturais, designada por hidroarsenismo, converteu-se num problema sanitário internacional afectando, actualmente, mais de 40 milhões de pessoas e manifesta-se pelo aparecimento de lesões cutâneas graves e pela ocorrência de perturbações neurológicas. As conclusões de vários estudos epidemiológicos vieram confirmar a potencial acção cancerígena de algumas espécies de arsénio, quando presentes em concentrações elevadas, levando a OMS, em 1993, a recomendar um valor guia muito restritivo (0,01 mg/L) como norma de qualidade das águas destinadas a consumo humano, Esta recomendação foi adoptada na legislação portuguesa em vigor (Decreto-Lei n.º 306/2007, de 27 de Agosto), tendo a sua aplicação originado alguns constrangimentos operacionais e de sustentabilidade às entidades gestoras de sistemas de abastecimento público de água com origens de água (geralmente subterrâneas) em que os valores da concentração de arsénio excedem, ainda que sazonalmente, este limite paramétrico mais restritivo. Efectivamente, em algumas regiões afectadas pela presença de arsénio nas águas naturais a substituição dessas fontes de abastecimento, em certas épocas do ano, por outra mais segura pode ser impossível ou demasiado dispendiosa, mesmo numa perspectiva de complementaridade, visando uma diluição dos volumes de água provenientes das captações afectadas. Assim sendo, a remoção do arsénio na água bruta coloca-se como a única opção viável para se obter uma água segura para consumo humano, tornando pertinente o incremento, a nível europeu, de investigação aplicada visando o desenvolvimento de tecnologias inovadoras de remoção de arsénio, mais eficientes e sustentáveis, nomeadamente para sistemas de abastecimento a pequenos e médios aglomerados populacionais Este trabalho inicia-se com uma referência às causas do aparecimento de arsénio em diversas massas de água e à presença de arsénio em alguns dos mananciais hídricos da Península Ibérica, tendo-se efectuado uma pesquisa sobre os principais impactos do hidroarsenismo na saúde humana. Procedeu-se também a uma revisão dos principais processos de tratamento para remoção de arsénio, não só os convencionais, como também alternativos (oxidação avançada e fotocatálise heterogénea) e a uma análise das respectivas eficiências, de modo a estabelecer critérios de selecção dessas tecnologias em função das características da água bruta a tratar e/ou dos esquemas de tratamento, no caso de ETA já existentes. Por fim, apresenta-se uma metodologia inovadora de remoção de arsénio, baseada numa conjugação dos processos convencionais com técnicas de oxidação solar, visando a sustentabilidade dos sistemas de tratamento, através duma redução significativa dos custos de exploração e de um aproveitamento racional de energias renováveis

Automated image analysis of lung branching morphogenesis from microscopic images of fetal rat explants

Article ID 820214Background. Regulating mechanisms of branching morphogenesis of fetal lung rat explants have been an essential tool for molecular research. This work presents a new methodology to accurately quantify the epithelial, outer contour, and peripheral airway buds of lung explants during cellular development from microscopic images. Methods. The outer contour was defined using an adaptive and multiscale threshold algorithm whose level was automatically calculated based on an entropy maximization criterion. The inner lung epithelium was defined by a clustering procedure that groups small image regions according to the minimum description length principle and local statistical properties. Finally, the number of peripheral buds was counted as the skeleton branched ends from a skeletonized image of the lung inner epithelia. Results. The time for lung branching morphometric analysis was reduced in 98% in contrast to the manual method. Best results were obtained in the first two days of cellular development, with lesser standard deviations. Nonsignificant differences were found between the automatic and manual results in all culture days. Conclusions. The proposed method introduces a series of advantages related to its intuitive use and accuracy, making the technique suitable to images with different lighting characteristics and allowing a reliable comparison between different researchers.The authors acknowledge Foundation for Science and Technology (FCT), Portugal, for the fellowship with the references: SFRH/BD/74276/2010 and SFRH/BPD/46851/2008

The effect of bovine milk lactoferrin on human breast cancer cell lines

The evidence that biologically active food components are key environmental factors affecting the incidence of many chronic diseases is overwhelming. However, the full extent of such components in our diet is unknown, as well as our understanding of their mechanisms of action. Beyond their interaction with the gut and intestinal immune functions, more benefits are being tested for whey proteins such as lactoferrin, namely as anti-cancer agents. Lactoferrin is an iron-binding protein that has been reported to inhibit several types of cancer. In the present work, the effects of bovine milk lactoferrin on human breast cancer HS578T and T47D cells were studied. The cells were either untreated or submitted to lactoferrin concentrations ranging from 0. 125 to 125 μM. Lactoferrin decreased 47% and 54% the cell viability of HS578T and T47D, respectively, and increased apoptosis about twofold for both cell lines. Proliferation rates decreased between 40.3 and 63.9% for HS578T and T47D, respectively. T47D cell migration decreased in the presence of the protein. Although the mechanisms of action have still not been unrevealed, the results gathered in this work suggest that lactoferrin interferes with some of the most important steps involved in cancer development.(undefined

Technical and economical evaluation of modular multilevel converters for the electrical power grid interface

Over the past few years, it has been verified a raise in the demand, as well as the price of electricity, urging the need for the development of more efficient power converting systems. Two of the most used power converters are the AC-DC, commonly known as rectifier, and the DC-AC, commonly known as power inverter. There are many different topologies for both the referred converters, but one of the most common is the H-Bridge, which can operate as a bidirectional converter that enables the possibility of a single power converter working either as an active rectifier or a grid-tied power inverter, according to the application in use. In this paper, a Modular Multilevel Converter topology is presented and compared to the most conventional bidirectional power converter, discussing both technical and economical details recurring to simulations and a critic analysis of the results, which allows the understanding of the tied relation between economics and engineering, optimizing the functionality of the converter, as well as the costs associated with R&D and production in short term, and the efficiency in the long term.This work has been supported by FCT -Fundacao para a Ciencia 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

Design and development of an inexpensive aquatic swarm robotics system

Swarm robotics is a promising approach characterized by large numbers of relatively small and inexpensive robots. Since such systems typically rely on decentralized control and local communication, they exhibit a number of interesting and useful properties, namely scalability, robustness to individual faults, and flexibility. In this paper, we detail the design and development process of a swarm robotics platform composed of autonomous surface robots, which was designed in order to study the use of robotic swarms in real-world environments. Our aquatic surface robots where manufactured using digital fabrication techniques, such as 3D printing and CNC milling, and all hardware and software has been made available as open-source, thus allowing third-parties to customize and further improve our platform.info:eu-repo/semantics/acceptedVersio