2,160 research outputs found
Can the mitochondrial malondialdehyde content be an useful tool to distinguish ecological quality of Petromyzon marinus habitat?
The sea lamprey is an anadromous species that migrates twice during its life cycle between freshwater and seawater. Microphagous larvae generally spend 4–5 years burrowed in the substrate of rivers and streams before undergoing metamorphosis that ends with the beginning of the juvenile trophic migration. Once metamorphosis is complete, sea lamprey juvenile downstream migrants are fully tolerant to 35 PSU seawater. Pollution resulting from industrial effluents may disturb the seawater acclimatization causing oxidative damages, and ultimately may lead to a decrease of sea lamprey population. The aim of this study was to compare salt acclimation of sea lamprey juveniles captured in river basins with different levels of aquatic pollution, using mitochondrial glutathione and malondialdehyde of gills and liver as markers of physiological stress and cell damages. The results showed that juveniles from Lima basin exhibited the highest levels of mitochondrial malondialdehyde in gills, even though significant changes in the stress markers of mitochondrial gills of all animals subject to salt acclimation were not detected. In addition, an increase in the oxidative damages of hepatic mitochondria of macrophthalmia from Vouga basin suggests the occurrence of metabolic failures with the potential to disturb the capacity to adaptation to the marine environment
Hepatic mitochondrial content in malondialdehyde may be a marker of sea lamprey contact with atrazine
The atrazine attracts special attention as pollutant because of itspersistence in the aquatic environment. Although this herbicide has been studied in teleost, its toxicity in the sea lamprey, Petromyzon marinus is still poorly understood. Oxidative stress may occur if chemical pollutants contribute to block the capacity of mitochondria to generate ATP with continuous production of reactive oxygen species (ROS), disturbing the success of P. marinus seawater acclimation. So, the aim of this study was to evaluate how atrazine influences the malondialdehyde (MDA), glutathione (GSH) and glutathione disulfide (GSSG) contents of gills and liver mitochondria of juveniles from Lima river basin, Portugal during salt acclimation. Sampling occurred at the beginning of the P. marinus downstream migration. The sampled juveniles were transported alive to the laboratory and maintained in 200 l tanks with LSS 8 life support system. Two groups of 40 specimens were hold in tanks with 50 or 100 lg/l atrazine, during 30 days. The salinity was gradually increased from 0 to 35 psu,following a three step procedure during a 30 days period. The control group was maintained in freshwater without atrazine. Mitochondria obtained by centrifugation at 15000 g, 30 min, 4°C, of tissues homogenates prepared in 50 mM Tris-HCl pH 7.5 buffer were used in determination of ROS, MDA, GSH and GSSG by fluorescence. The statistical analysis were performed by ANOVA I and Duncan (p < 0.05), using SPSS 22 for Windows.The results showed that in P. marinus juveniles, no significant changes in the markers of oxidative stress and cell damages were detected in the mitochondrial gills. Nevertheless, in the animals exposed to 50 lg/l atrazine the content in glutathione and GSSG increased. A similar pattern of stress markers was detected in hepatic mitochondria. However, in the presence of atrazine, the MDA level of the mitochondria of liver increased threefold in the animals during salt acclimation. The high level of mitochondrial damages, detected in the hepatic mitochondria of macrophthalmia treated with atrazine, suggests that herbicide exposure caused metabolic failures which can disturb the adaptation of these specimens to the oceanic feeding phase. The hepatic mitochondrial MDA levels of P. marinus, may eventually detect sea lamprey contact with chlorine herbicides
PREVALÊNCIA DE LESÕES ORAIS E MAXILOFACIAIS EM CRIANÇAS DE 0 A 12 ANOS DE IDADE DE ACORDO COM CARACTERÍSTICAS INDIVIDUAIS E SOCIODEMOGRÁFICAS
Probabilistic failure rate model of a tidal turbine pitch system
This is the final version. Available on open access from Elsevier via the DOI in this recordAccurate reliability prediction for tidal turbines is challenging due to scarce reliability data. To
achieve commercialization, it is widely acknowledged that reductions in maintenance costs are vital and robust
component reliability assessments can help drive this. For established technologies, reliability prediction either
involves a statistical assessment of historical failure data, or a physics of failure approach based on dedicated
accelerated testing. However, for low/mid Technology Readiness Level tidal developers these common
approaches are difficult. Thus, developers require a method of making reliability predictions for components
in the absence of tidal turbine specific failure data and physical testing results. This paper presents a failure
rate model for a tidal turbine pitch system using empirical Physics of Failure equations, with associated
uncertainties. Critical component design parameters are determined and their effects on the failure rate
investigated via a sensitivity analysis. The modelled failure rate is then compared with wind turbine failure
data from a series of turbines. The tidal turbine failure rate is approximately 50% lower, however high
reliability requirements mean this is unlikely to be acceptable. The developed model can assist turbine
developers in estimating failure rates and determining reliability critical design parameters for the failure
critical pitch system.Engineering and Physical Sciences Research Council (EPSRC)European Regional Development Fund (ERDF
O DISCURSO NAS MISSIVAS DE CLARICE LISPECTOR EM ‘MINHAS QUERIDAS’
Pretende-se analisar neste artigo como se revela o discurso nas missivas de Clarice Lispector, a partir dos trechos oriundos das suas correspondências pessoais, mantida com suas irmãs, durante os anos em que viveu em Berna na Suíça. Para tanto, será utilizado como respaldo teórico as contribuições de Michel Foucault, Gilles Deleuze e Felix Guattari. Pretende-se verificar como o poder e o discurso se desdobram na linguagem expressa no conteúdo das missivas. Ao fim, pode-se concluir que o discurso nada mais é do que a expressão do mundo, a verbalização de uma realidade, a interligação da linguagem com a experiência, na qual o sujeito se encontra inserido. Clarice sozinha em seu exílio utilizou-se do poder do discurso para recorrer ao outro, dependia deste discurso, era seu modo de sobrevivência e produção de subjetividade. Ao corresponder com suas irmãs, ela ressignificava seu próprio mundo, e é justamente sob este esta base, que se pode considerar a linguagem como uma prática, tendo em vista que ela pratica uma significação e ressignificação de mundo que está sempre em descontinuidades, constantemente transformando-se
Step down tests are the tasks that most differentiate the kinematics of women with patellofemoral pain compared to asymptomatic controls.
BACKGROUND: Studies evaluating kinematics lead to different conclusions, not all changes appear in all assessed tasks and in all subgroups of patients with patellofemoral pain (PFP). The inconsistencies between studies could be reduced if we knew which task separates patients best from healthy controls. RESEARCH QUESTION: Identify which functional task, between gait, forward step down (FSD), lateral step down (LSD), stair ascent and descent and propulsion and landing phase of the single leg hop test (SLHT), differentiates the three-dimensional kinematics of women with patellofemoral pain from asymptomatic women. METHODS: This cross-sectional study evaluated thirty-five PFP and thirty-five asymptomatic women during the execution of the following tasks: gait, FSD, LSD, stair ascent and descent and the propulsion and landing phase of single leg hop test. Frontal, sagittal and transverse plane angles of the trunk, pelvis and hip, frontal and sagittal plane angles of the knee, ankle dorsiflexion, foot progression angle and hindfoot eversion were analyzed through the Movement Deviation Profile (MDP). To compare the groups, the multivariate analysis with Bonferroni post hoc test were used, with a significance level of p < 0.01. To identify which task presented the most difference between the groups, the Z-score of the mean MDP was calculated. RESULTS: For all tasks, the groups presented significant differences. According to the Z-score, the groups got farther apart considering the MDP for each task in the following order: LSD (7.97), FSD (7.62), landing phase of SLHT (3.43), gait (2.85), propulsion phase of SLHT (1.64), descending stairs (1.63) and ascending stairs (1.00). SIGNIFICANCE: We suggest that step down tests should be included in the assessment of PFP patients, since these tests most differentiate the kinematics of women with and without PFP. Identifying the tasks with the highest sensitivity to detect the kinematic differences is expected to improve clinical decision-making
ANÁLISE DO CONHECIMENTO DOS ACADÊMICOS DA UNIEVANGÉLICA SOBRE O FLÚOR
O flúor é utilizado na prevenção e controle da doença cárie, pois interfere no processo de desmineralização e remineralização dos dentes. O conhecimento sobre os métodos de utilização do flúor e seus efeitos é importante para toda a população para que o flúor seja utilizado de maneira adequada.
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Freshwater transport in the coupled ocean-atmosphere system: a passive ocean
Conservation of water demands that meridional ocean and atmosphere freshwater transports (FWT) are of equal magnitude but opposite in direction. This suggests that the atmospheric FWT and its associated latent heat (LH) transport could be thought of as a \textquotedblleft coupled ocean/atmosphere mode\textquotedblright. But what is the true nature of this coupling? Is the ocean passive or active?
Here we analyze a series of simulations with a coupled ocean-atmosphere-sea ice model employing highly idealized geometries but with markedly different coupled climates and patterns of ocean circulation. Exploiting streamfunctions in specific humidity coordinates for the atmosphere and salt coordinates for the ocean to represent FWT in their respective medium, we find that atmospheric FWT/LH transport is essentially independent of the ocean state. Ocean circulation and salinity distribution adjust to achieve a return freshwater pathway demanded of them by the atmosphere. So, although ocean and atmosphere FWTs are indeed coupled by mass conservation, the ocean is a passive component acting as a reservoir of freshwater
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