10,150 research outputs found

    Ab initio study of the elastic behavior of MgSiO3 ilmenite at high pressure

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    We investigate the athermal high pressure behavior of the elastic properties of MgSiO3 ilmenite up to 30 GPa using the ab initio pseudopotential method. Our results at zero pressure are in good agreement with single-crystal elasticity measurements. The elastic anisotropy is shown to decrease slightly under compression and hence to remain substantial (25 to 20% shear wave anisotropy and 16 to 10% longitudinal wave anisotropy) over the pressure regime studied. The directions of fastest and slowest wave propagation are found to change slightly with pressure as determined by the pressure dependence of c(14) and c(25). Comparisons with the elastic behavior of other deep transition zone phases such as ringwoodite and garnet show that ilmenite is likely to be the fastest and most anisotropic mineral in this region. Large contrasts (approximate to 10%) in velocities and densities between ilmenite and garnet are suggested to be significant for the interpretation of lateral structure in the transition zone

    Law as Counterspeech

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    A growing body of work in free speech theory is interested in the nature of counterspeech, i.e. speech that aims to counteract the effects of harmful speech. Counterspeech is usually defined in opposition to legal responses to harmful speech, which try to prevent such speech from occurring in the first place. In this paper we challenge this way of carving up the conceptual terrain. Instead, we argue that our main classificatory division, in theorising responses to harmful speech, should be between pro-discursive and anti-discursive responses. Some legal responses to harmful speech, so we argue, make a positive discursive contribution in their own right. That is, legal restrictions on harmful speech can have a function that is importantly similar to speech that aims at countering the effects of harmful speech

    Effects of microalgal exudates and intact cells on subtropical marine zooplankton

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    Harmful algal blooms (HABs) affect coastal waters worldwide and very often lead to the disruption of seafood harvesting and commercial activities, because of potential hazards to human health associated with the consumption of contaminated mussels, crustaceans and fish. HAB events are frequently caused by outbreaks of toxin-producing dinoflagellates, which are subject to top-down control by zooplankton. The aim of this study was to analyze the effects of dinoflagellate exudates and intact cells on the survivorship and mobility of zooplankton taxa from a subtropical location (Ubatuba, Brazil). Lethal effects were observed in five out of six taxa investigated, three of which (copepod nauplii, tintinnids and gastropod larvae) when exposed to dinoflagellate exudates and two (rotifers and brachyuran zoeae) when exposed to intact cells. In addition, gastropod larvae displayed mobility impairment during exposure to dinoflagellate exudates. Only polychaete larvae were not apparently affected during the course of the experiments. Zooplankton responses usually varied according to the dinoflagellate species tested. For instance, exudates from Alexandrium tamiyavanichii, Gonyaulax sp. and Gymnodinium sp. decreased survivorship of planktonic copepod nauplii but did not affect bottom-dwelling harpacticoid nauplii, which were in turn killed by exudates from Prorocentrum lima, a epibenthic dinoflagellate. These results suggest that HAB events do not cause indiscriminate zooplankton mortality, but may instead generate community shifts and complex cascading effects through the pelagic and benthic food web. Species-specific monitoring of zooplankton responses to HABs is therefore an important step to understand the ecological implications of dinoflagellate outbreaks in coastal waters, and their impact on marine farming activities

    Quantification of respiratory parameters in patients with temporal lobe epilepsy

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    Dysfunction affecting cardiac or pulmonary systems has been postulated as a major factor in sudden death in epilepsy (SUDEP). Whilst the majority of studies of cardiorespiratory function have focused on changes during seizures, here we investigate whether epilepsy influences basal respiratory parameters in patients with temporal lobe epilepsy (TLE) during the interictal period. Spirometry was performed in 10 females and 10 males. Measurements of Vital Capacity (VC), Forced Vital Capacity (FVC), Forced Expiratory Volume in the first second (FEV1) and ratios of FEV1 to FVC (FEV1/FVC) were obtained, and these values were analyzed as percentages of predicted values. None of the patients had chronic obstructive pulmonary disease and no significant alterations in respiratory function tests were found among these patients. No association between seizure frequency, antiepileptic drugs and SUDEP could be found in this study. Although the study did not identify any specific respiratory abnormality in TLE patients during the interictal period, re-evaluation of clinical data on pulmonary disorders in people with epilepsy should be better investigated

    Use of pectin in the storage of mangaba fruits (Hancorniaspeciosa Gomes) associated with refrigeration

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    The objective of this study was to evaluate the storage potential of mangaba fruits coated with pectin biofilm stored in biochemical oxygen demand (BOD) (22 ± 1°C) under modified atmosphere. Scanning electron microscopy (SEM) was used to analyze the physical and chemical changes, vitamin C content, soluble solid, titratable acidity and turgor pressure, and colour and physical structure of the fruits during storage. The physico-chemical and colour analyses of the fruit were done with four treatment groups: control and pectin solutions of 4, 6 and 8% (w / v) at three day intervals for two weeks. The pectin solution and BOD were effective for the conservation of soluble solids of mangaba. However, the levels of acidity, vitamin C and turgor pressure showed that the fruits got ripe during the study and were kept until the sixth day of the test compared to control fruits. The best results were determined for the mangaba coated with 6 to 8% pectin.Key words: Conservation, film solution, post-harvest, firmness

    Potential application of Saccharomyces cerevisiae strains for the fermentation of banana pulp

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    This paper aimed at evaluating the fermentation behavior of selected Saccharomyces cerevisiae strains in banana pulp and they were compared with commercial yeast (baker’s yeast) for subsequent production of distilled spirits. Five types of microorganisms were used: Four yeast strains obtained from accredited microbiology laboratories were isolated from domestic cachaça distilleries (UNICAMPV1, UFMG-A905, UFMG-A1007 and UFMG-A1240) and commercial pressed yeast (COMMERCIAL-yeast). The fermentation parameters of the studied S. cerevisiae strains were significantly different. COMMERCIAL-yeast and UNICAMP-V1 strain presented higher ethanol yield and better yeast efficiency in converting total reducing sugars (TRS) into alcohol, with ethanol yields of 83.07 and 94.06%, and yeast efficiency of 90.75 and 96.41%, respectively for UNICAMP V1 and COMMERCIAL-yeast. The higher alcohol contents of 82.26 and 78.05 mg/100 ml anhydrous alcohol were obtained by the UNICAMP-V1 and COMMERCIAL-yeast, respectively. No significant differences in fermentative parameters were observed between COMMERCIAL-yeast and UNICAMP-V1 strain. The UFMG-A1240 strain showed the lowest ethanol yield and therefore not suitable for the production of distilled spirits made of bananas, despite being useful for the production of cachaça. Methanol contents did not significantly vary among the five strains tested, except for UFMG-A1007, which produced significantly higher quantities of 0.19 ml/100 ml anhydrous alcohol. However, higher alcohols contents varied significantly between the five strains tests, with the UFMG-A1007 and UFMG-A1240 strains producing the lowest quantities of higher alcohols (30.04 and 48.69 mg/100 ml anhydrous alcohol, respectively). In conclusion, the S. cerevisiae strains UNICAMP-V1 and the COMMERCIAL-yeast showed better fermentation behavior, did not produce high methanol and higher alcohols amounts, and therefore were recommended for the production of distilled spirits made of banana in pilot-scale plants.Key words: Yeast, Saccharomyces cerevisiae, alcoholic fermentation, banana spirits

    Chemical characterization of passion fruit (Passiflora edulis f. flavicarpa) seeds

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    The aim of this study was to determine the chemical characteristics of passion fruit seeds and their oil for possible use in human food and reduction of organic waste from fruit industrialization. Passion fruit seeds were analyzed for moisture, lipids, proteins, ash, fibers, titratable acidity, pH, soluble solids and antioxidant activity. The oil was characterized for parameters such as acid value, saponification, iodine and peroxide. The content of oil extracted demonstrates that it has good potential for  industrial utilization. According to analyses, the oil has characteristics similar to conventional edible oils such as soybean, and may be a new source of human consumption. Passion fruit seeds have high nutritional value, proving to be a promising product, mainly because it contains  significant amounts of proteinase. Therefore, passion fruit seeds and their oil should be used as raw material in the food, chemical and pharmaceutical industry, as they have beneficial features.Key words: Industrial utilization, characterization, by-products

    Application of biofilms in the post-harvest conservation of pequi (Caryocar brasiliense Camb.)

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    Pequi (Caryocar brasiliense Camb.), fruit characteristic of the Brazilian cerrado, has sensory and nutritional characteristics, pleasant flavor and aroma and considerable presence of lipids and fiber, essential for human consumption. The aim of this study was to assess the post-harvest conservation of this fruit by using different sources of biofilms as a means to ensure the maintenance of fruit physical and chemical characteristics in order to increase its shelf life. Fruits were submitted to four treatments: control (no coating) (T1); 0.5% w/w carnauba wax (T2); 1% w/w cassava starch (T3) and 1.5% w/w xanthan gum (T4) stored during 15 days at BOD at 22 ± 0.1°C and submitted every three days to analyses of titratable acidity, soluble solid, pH, turgor pressure, vitamin C, weight loss and physical structure by scanning electron microscopy. The pH levels and turgor pressure showed expected values for control and coated pequi fruits. The vitamin C, titratable acidity, soluble solids contents and weight loss showed that coatings did not achieve satisfactory results. However, fruits coated with cassava starch showed the best conservation results during the experimental period.Key words: Coatings, shelf life, storage

    Extending the applicability of the dose addition model to the assessment of chemical mixtures of partial agonists by using a novel toxic unit extrapolation method

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    This article has been made available through the Brunel Open Access Publishing Fund.Dose addition, a commonly used concept in toxicology for the prediction of chemical mixture effects, cannot readily be applied to mixtures of partial agonists with differing maximal effects. Due to its mathematical features, effect levels that exceed the maximal effect of the least efficacious compound present in the mixture, cannot be calculated. This poses problems when dealing with mixtures likely to be encountered in realistic assessment situations where chemicals often show differing maximal effects. To overcome this limitation, we developed a pragmatic solution that extrapolates the toxic units of partial agonists to effect levels beyond their maximal efficacy. We extrapolated different additivity expectations that reflect theoretically possible extremes and validated this approach with a mixture of 21 estrogenic chemicals in the E-Screen. This assay measures the proliferation of human epithelial breast cancers. We found that the dose-response curves of the estrogenic agents exhibited widely varying shapes, slopes and maximal effects, which made it necessary to extrapolate mixture responses above 14% proliferation. Our toxic unit extrapolation approach predicted all mixture responses accurately. It extends the applicability of dose addition to combinations of agents with differing saturating effects and removes an important bottleneck that has severely hampered the use of dose addition in the past. © 2014 Scholze et al
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