1,272 research outputs found

    Liquid crystal phase and waterlike anomalies in a core-softened shoulder-dumbbells system

    Get PDF
    Using molecular dynamics we investigate the thermodynamics, dynamics and structure of 250 diatomic molecules interacting by a core-softened potential. This system exhibits thermodynamics, dynamics and structural anomalies: a maximum in density-temperature plane at constante pressure and maximum and minimum points in the diffusivity and translational order parameter against density at constant temperature. Starting with very dense systems and decreasing density the mobility at low temperatures first increases, reach a maximum, then decreases, reach a minimum and finally increases. In the pressure-temperature phase diagram the line of maximum translational order parameter is located outside the line of diffusivity extrema that is enclosing the temperature of maximum density line. We compare our results with the monomeric system showing that the anisotropy due to the dumbbell leads to a much larger solid phase and to the appearance of a liquid crystal phase. the double ranged thermodynamic and dynamic anomalies.Comment: 14 pages, 5 figure

    Desidratação osmótica de pêssego com calda açucarada e calda à base de mel.

    Get PDF
    Comunicação da qual só está disponível o resumo.A desidratação é um processo que consiste na eliminação de água de um produto por evaporação. Com o aumento da produção e sazonalidade de diversos frutos a produção de fruta desidratada pode ser uma alternativa para escoamento dos excedentes. Os produtos alimentares podem ser desidratados por processos baseados na vaporização, sublimação, remoção de água por solventes ou na adição de agentes osmóticos. Nos últimos anos, a desidratação de alimentos tem sido objeto de vários estudos no sentido de produzir alimentos desidratados, que conservem ou melhorem as características sensoriais e valor nutricional, garantindo um custo adequado. Este trabalho teve como objetivo avaliar os parâmetros de qualidade de rodelas de pêssego submetidas a desidratação osmótica utilizando dois tipos de caldas. Numa fase inicial foram realizados vários ensaios a fim de selecionar um programa de secagem adequado, que não proporcionasse alteração significativa da cor da fruta (determinado por colorímetro no sistema CIELAB), fosse adequado do ponto de vista microbiológico e tivesse a preferência dos provadores na avaliação sensorial. O programa de secagem selecionado tem a duração de 12 horas: 30 min até atingir a temperatura de 520C; 10,5 horas à temperatura de 520C; 1 hora para estabilização. De seguida foram testadas 4 caldas: calda açucarada com três concentrações diferentes de frutose (C1: 365 g/L, C2: 490 g/L e C3: 735 g/L) e uma calda à base de mel (diluição de 1:1 m/v); para desidratação osmótica seguida de secagem. Este programa de secagem teve a duração de 10 horas. Para estas 4 amostras foi efetuada uma prova de ordenação tendo a amostra C3 (735 g/L de frutose) obtido a maior pontuação. Para as amostras selecionadas de secagem simples e secagem com pré-tratamento de desidratação osmótica foram efetuadas as seguintes determinações: humidade (PT.LFQ.0135-Método interno); gordura (AOAC 2003.06); proteína (PT.LFQ.0105-Método interno); cinzas (AOAC 934.03); hidratos de carbono (cálculo); valor energético (cálculo); sódio (ICP-OES); sal (cálculo); glucose; frutose; sacarose; maltose; lactose (PT.LFQ.0129-Método interno). Os resultados demonstraram que o produto com pré-tratamento, embora mais apreciados pelos provadores apresenta um teor de açúcares (frutose) superior, inerente ao tratamento e um teor de humidade, gordura e proteína inferior. É de referir, no entanto, que este trabalho deve ser continuado de modo a aferir as melhores condições para a secagem após a desidratação osmótica (especialmente para a calda de mel) dado que os provadores gostaram do sabor da amostra tratada com mel mas pontuaram pior devido à elevada gomosidade que apresentava.info:eu-repo/semantics/publishedVersio

    Autonomous platform for distributed sensing and actuation over bluetooth

    Get PDF
    This paper presents a short range wireless network platform based on Bluetooth technology and on a Round Robin scheduling algotithm. The main goal is to provide an application independent platform in order to support a distributed data acquisition and control system used to control a model of a greenhouse. This platform enables the advantages of wireless communications while assuring low weight, small energy consumption and reliable communications

    The upper respiratory tract microbiota of healthy adults is affected by Streptococcus pneumoniae carriage, smoking habits, and contact with children.

    Get PDF
    BACKGROUND The microbiota of the upper respiratory tract is increasingly recognized as a gatekeeper of respiratory health. Despite this, the microbiota of healthy adults remains understudied. To address this gap, we investigated the composition of the nasopharyngeal and oropharyngeal microbiota of healthy adults, focusing on the effect of Streptococcus pneumoniae carriage, smoking habits, and contact with children. RESULTS Differential abundance analysis indicated that the microbiota of the oropharynx was significantly different from that of the nasopharynx (P < 0.001) and highly discriminated by a balance between the classes Negativicutes and Bacilli (AUC of 0.979). Moreover, the oropharynx was associated with a more homogeneous microbiota across individuals, with just two vs. five clusters identified in the nasopharynx. We observed a shift in the nasopharyngeal microbiota of carriers vs. noncarriers with an increased relative abundance of Streptococcus, which summed up to 30% vs. 10% in noncarriers and was not mirrored in the oropharynx. The oropharyngeal microbiota of smokers had a lower diversity than the microbiota of nonsmokers, while no differences were observed in the nasopharyngeal microbiota. In particular, the microbiota of smokers, compared with nonsmokers, was enriched (on average 16-fold) in potential pathogenic taxa involved in periodontal diseases of the genera Bacillus and Burkholderia previously identified in metagenomic studies of cigarettes. The microbiota of adults with contact with children resembled the microbiota of children. Specifically, the nasopharyngeal microbiota of these adults had, on average, an eightfold increase in relative abundance in Streptococcus sp., Moraxella catarrhalis, and Haemophilus influenzae, pathobionts known to colonize the children's upper respiratory tract, and a fourfold decrease in Staphylococcus aureus and Staphylococcus lugdunensis. CONCLUSIONS Our study showed that, in adults, the presence of S. pneumoniae in the nasopharynx is associated with a shift in the microbiota and dominance of the Streptococcus genus. Furthermore, we observed that smoking habits are associated with an increase in bacterial genera commonly linked to periodontal diseases. Interestingly, our research also revealed that adults who have regular contact with children have a microbiota enriched in pathobionts frequently carried by children. These findings collectively contribute to a deeper understanding of how various factors influence the upper respiratory tract microbiota in adults. Video Abstract

    Re-evaluation of Streptococcus pneumoniae carriage in Portuguese elderly by qPCR increases carriage estimates and unveils an expanded pool of serotypes

    Get PDF
    Streptococcus pneumoniae (pneumococcus) is a leading cause of infections worldwide. Disease is preceded by asymptomatic colonization of the upper respiratory tract. Classical culture-based methods (CCBM) suggest that colonization in the elderly is <5%. Recently, use of qPCR has challenged these observations. We estimated pneumococcal carriage prevalence and serotypes among Portuguese elderly using qPCR and compared results with those obtained by CCBM. Nasopharyngeal and oropharyngeal paired samples (599 each) of individuals over 60 years living in nursing (n = 299) or family (n = 300) homes were screened for the presence of pneumococci by qPCR targeting lytA and piaB. Positive samples were molecular serotyped. Use of qPCR improved detection of pneumococci in oropharyngeal samples compared to CCBM: from 0.7% to 10.4% (p < 0.001) in the nursing home collection, and from 0.3% to 5.0% (p < 0.001) in the family home collection. No significant differences were observed between both methods in nasopharyngeal samples (5.4% vs. 5.4% in the nursing homes; and 4.3% vs. 4.7% in the family homes). Twenty-one serotypes/serogroups were detected by qPCR compared to 14 by CCBM. In conclusion, use of qPCR suggests that pneumococcal carriage in Portuguese elderly is approximately 10%, and unveiled a large pool of serotypes. These results are important to understand progression to disease and impact of pneumococcal vaccines in the elderly.publishersversionpublishe

    Anticorpos IgG em camundongos coinfectados por Toxocara canis e outros helmintos e por protozoários parasitos

    Get PDF
    The immune response expressed by IgG antibodies in BALB/c mice experimentally infected with Toxocara canis, was studied with the aim of verifying the possible in vivo cross-reactivity between antigens of T. canis and other parasites (Ascaris suum, Taenia crassiceps, Schistosoma mansoni, Strongyloides venezuelensis and Toxoplasma gondii). Experiments included three groups of mice: one infected only by T. canis, another with one of the other species of parasites and a third concomitantly infected with T. canis and the other species in question. Animals were bled by orbital plexus at 23, 38 and 70 days post infection (p.i.). Sera were analyzed for anti-Toxocara antibodies by ELISA and Immunoblotting, using excretion-secretion antigens (ES), obtained from culture of third-stage larvae of T. canis. For all experiments a control group comprised by ten non-infected mice was used. Only in the case of A. suum infection, in these experimental conditions, the occurrence of cross-reactivity with T. canis was observed. However, in the case of co-infection of T. canis - S. mansoni, T. canis - S. venezuelensis and T. canis - T. crassiceps the production of anti-Toxocara antibodies was found at levels significantly lower than those found in mice infected with T. canis only. Co-infection with S. mansoni or S. venezuelensis showed lower mortality rates compared to what occurred in the animals with single infections. Results obtained in mice infected with T. canis and T. gondii showed significant differences between the mean levels of the optical densities of animals infected with T. canis and concomitantly infected with the protozoan only in the 23rd day p.i.Estudou-se a resposta imune humoral expressa por anticorpos da classe IgG em camundongos BALB/c experimentalmente infectados com Toxocara canis em duas situações distintas. Na primeira, com o objetivo de verificar in vivo a possível reatividade cruzada entre Toxocara canis e outros parasitos (Ascaris suum, Taenia crassiceps, Schistosoma mansoni, Strongyloides venezuelensis e Toxoplasma gondii), foram realizados experimentos constituídos por três grupos de camundongos: um infectado apenas por Toxocara canis, outro com uma das demais espécies de parasitos estudados e um terceiro concomitantemente infectado por Toxocara canis e a espécie em questão. Todos os animais foram sangrados, através do plexo orbitário, 23, 38 e 70 dias após infecção. Os soros foram analisados para a presença de anticorpos anti-Toxocara por meio de teste imunoenzimático (ELISA) e por Immunoblotting, empregando-se antígeno de excreção-secreção (ES), obtido a partir da cultura de larvas de terceiro estádio de Toxocara canis. Para todos os experimentos utilizou-se grupo controle negativo constituído por 10 camundongos não infectados. Apenas no caso da infecção por Ascaris suum, nas condições experimentais observadas, logrou-se demonstrar ocorrência de reatividade cruzada com antígenos de Toxocara canis. Verificou-se, entretanto, no caso das coinfecções entre Toxocara canis-Schistosoma mansoni, Toxocara canis-Strongyloides venezuelensis e Toxocara canis-Taenia crassiceps produção de anticorpos anti-Toxocara em níveis significativamente inferiores do que os encontrados nos camundongos infectados somente por Toxocara canis. Nas coinfecções com Schistosoma mansoni ou Strongyloides venezuelensis observou-se, também, menor taxa de letalidade quando comparada à ocorrida nos animais com as respectivas infecções simples

    Phylogeny, biogeography and ecology of azorean termites

    Get PDF
    Three species of termites are currently known in the archipelago (the European dampwood termite, Kalotermes flavicollis, the West Indies drywood termite, Cryptotermes brevis, and the Iberian subterranean termite Reticulitermes grassei). All these three species are "lower termites", that is, primitive species having simple galleries but not well formed nests, tending to be less socially advanced and to occur in more temperate latitudes, generally eating only wood but not other types of cellulose, and all having flagellates in the gut. Kalotermes flavicollis is native to most of the Mediterranean region and was probably introduced in the islands many decades ago through vineyard or orchard stocks. In Terceira Island, K. flavicollis is common in the heartwood of several trees and shrubs along the coast. Its colony members may exceed 1000 but the average colony has 600. This termite has been considered as a minor structural pest in a few houses, but structural infestations by this species only occur in association with moisture due to leaks or condensation. Cryptotermes brevis is the most destructive drywood termite pest in the world. Due to its exceptional ability to withstand wood with low moisture content it is able to attack all kinds of dead and dry wood with a strong preference for sapwood over heartwood. It attacks wood in service including structural timbers, beams, studs, rafters, cladding, flooring, molding, doors, window frames and wooden articles such as carvings, tools, picture frames, musical instruments, looms, bed posts, and almost all forms of wood. Serious infestations of this termite are currently known in São Miguel, Terceira, Faial and Santa Maria Islands. Local research has shown that colony size may range up to about 300 but that average colony size is only 45 individuals. Severe damage results not from individual colonies but from high levels of reinfestation leading to the establishment of large numbers of colonies. Successful colony foundation by this termite is promoted by the widespread occurrence of several anobiid beetles whose exit holes in wood provide ideal entrance holes for termite alates. Reticulitermes grassei, a subterranean termite, has only been found in the Azores Archipelago, in the Horta city (Faial Island) where it has been causing severe damage to a few buildings. Reticulitermes colonies may grow to millions of individuals promoted by numerous nymphoid reproductive’s which develop within colonies. Unlike the other two species, colonies of Reticulitermes may spread by tunnelling through the ground

    Benefits of multivariate statistical process control based on principal component analysis in solder paste printing process where 100% automatic inspection is already installed

    Get PDF
    The process of printing and inspecting solder paste deposits in Printed Circuit Boards (PCB) involves a very large number of variables (more than 30000 can be found in 3D inspection of high density PCBs). State of the art Surface Mount Technology (SMT) production lines rely on 100% inspection of all paste deposits for each PCB produced. Specification limits for Area, Height, Volume, Offset X and Offset Y have been defined based on detailed and consolidated studies. PCBs with paste deposits failing the defined criteria, are proposed to be rejected. The study of the variation of the rejected fraction over time, has shown that the process is not always stable and it would benefit from a statistical process control approach. Statistical process control for 30000 variables is not feasible with a univariate approach. On one side, it is not possible to pay attention to such a high number of Shewhart control charts. On the other side, the very rich information contained in the evolution of the correlation structure would be lost in the case of a univariate approach. The use of Multivariate Statistical Process Control based on Principal Component Analysis (PCA-MSPC) provides an efficient solution for this problem. The examples discussed in this paper show that PCA-MSPC in solder paste printing is able to detect and diagnose disturbances in the underlying factors which govern the variation of the process. The early identification of these disturbances can be used to trigger corrective actions before disturbances start to cause defects. The immediate confirmation of effectiveness of the corrective action is a characteristic offered by this method and can be observed in all the examples presented.INCT-EN - Instituto Nacional de Ciência e Tecnologia para Excitotoxicidade e Neuroproteção(UID/CEC/00319/2013). European Structural and Investment Funds in the FEDER component, through the Operational Competitiveness and Internationalization Programme (COMPETE 2020) Project nº 002814; Funding Reference: POCI-01-0247-FEDER-00281
    corecore