2,052 research outputs found

    Chemical potential as a source of stability for gravitating Skyrmions

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    A discussion of the stability of self gravitating Skyrmions, with a large winding number N, in a Schwarzschild type of metric, is presented for the case where an isospin chemical potential is introduced. It turns out that the chemical potential stabilizes the behavior of the Skyrmion discussed previously in the literature. This analysis is carried on in the framework of a variational approach using different ansaetze for the radial profile of the Skyrmion. We found a divergent behavior for the size of the Skyrmion, associated to a certain critical value μc\mu_c of the chemical potential. At this point, the mass of the Skyrmion vanishes. μc\mu_c is essentialy independent of gravitating effects. The stability of a large N skyrmion against decays into single particles is also discussed.Comment: 10 pages, 4 figures Small changes to the previous version and a new referenc

    Cellularity Description of Adipose Depots in Domesticated Animals

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    Cellularity of adipose tissue in domesticated animals varies not only with species, sex, age and management conditions but also with depot. Differences in depots are important in animal production because of the economic and welfare implications and in humans in relation to obesity. The final amount of fat and its composition depends on the differentiation of mesenchymal multipotent precursor cells into mature adipocytes (adipogenesis) capable of fatty acid and triglyceride synthesis (lipogenesis), both processes being regulated by different key adipogenic and lipogenic genes, some of are well known and have been described. Histologically, differences can be classified as hyperplasia (an increase in adipocyte number) and hypertrophy (an increase in adipocyte size), processes that can produce adipocyte size distributions that are not necessarily Gaussian. A detailed description of the type of adipocyte size distribution can help distinguish the different adipocyte populations within depots and characterise each not only in terms of the size but also the number of the constituting cells. This description can help better understand the development and role of the different depots. It can also help when analysing causal relationships with adipogenic drivers and lipogenic enzymes involved in lipid metabolism

    Obtaining preforms by additive fused deposition modelling (FDM) extrusion technology for the manufacture of high-performance composites

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    The composites industry is present in practically all industrial sectors with an annual growth rate of 5%. Its contribution to the priority "light-weighting" driver in the transport sector is key. The efficiency of the industry is made possible by the evolution of manufacturing processes that also improve the performance of the products obtained. For example, out-of-autoclave (OOA) processes can obtain high-performance composites such as those obtained by the autoclave process at lower costs. A key aspect in the development of this type of process is the preforming of continuous fibre reinforcements, which can achieve high fibre percentages while facilitating processing. Manufacturing these preforms currently requires multiple steps, equipment and tooling. TECNALIA's work developing the ADDICOMP technology, an alternative preform manufacturing method using an additive process based on Fused Deposition Modelling (FDM) is detailed in this article. This development is patented by Tecnalia and was conducted in 2 phases: (a) development of continuous fibre filaments coated with polymeric material and printable by FDM and (b) fine-tuning of FDM technology to print filaments with a very high content of continuous fibre

    Effect of fish and oil nature on frying process and nutritional product quality

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    The modifications on a lean fish (cod-Gadus morhua) and a fatty fish (farmed salmon-Salmo salar) after the application of pan-frying using 2 types of oil with different lipid profile (extra virgin olive oil and sunflower oil) was the aim of this study. Fat content and total energetic value increased significantly after the frying process only in the lean fish, without relevant changes in the fatty fish. Extra virgin olive oil led to a higher fat absorption rate than sunflower oil in both fish. Frying hardly affected the lipid profile of farmed salmon regardless the oil used, however it drastically changed in fried cod compared to raw cod. Omega-6/omega-3 ratio increased from 0.08 in raw cod to 1.01 and 6.63 in fried cod with olive oil and sunflower oil, respectively. In farmed salmon, the omega-6/omega-3 ratio was 0.38 (raw), and 0.39 to 0.58 in fried salmon. The amount of EPA + DHA slightly decreased with frying in salmon, and increased in cod. The type of oil has more influence in the nutritional fish quality for the lean fish compared to that of the fatty fish. The use of extra virgin olive oil was efficient to avoid a significant increase of the lipid oxidation intensity during frying in cod but not in salmon. PRACTICAL APPLICATION: Food modifies its composition and nutritional value with the application of cooking technologies. As most food table composition tables are based on raw food products, this article contributes with interesting data on pan-fried fish composition, which may improve the approach to achieve a real intake of healthy nutrients as omega 3 fatty acids

    Nitric oxide synthase-independent release of nitric oxide induced by KCl in the perfused mesenteric bed of the rat

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    The aim of the present study was to test whether the contractile responses elicited by KCl in the rat mesenteric bed are coupled to the release of nitric oxide (NO). Contractions induced by 70 mM KCl were coincident with the release of NO to the perfusate. The in vitro exposure to the nitric oxide synthase (NOS) inhibitor L-N(ω)-nitro-L-arginine methyl ester, L-NAME (1-100 μM) potentiated the vascular responses to 70 mM KCl and, unexpectedly, increased the KCl-stimulated release of NO. Moreover, even after the chronic treatment with L-NAME (70 mg/kg/day during 4 weeks), the KCl-induced release of NO was not reduced, whereas the potentiation of contractile responses was indeed achieved. The possibility that NOS had not been completely inhibited under our experimental conditions can be precluded because NOS activity was significantly inhibited after both L-NAME treatments. After the in vitro treatment with 1 to 100 μM L-NAME, the inhibition of NOS was concentration-dependent (from 50% to 90%). With regard to the basal release of NO, the inhibition caused by L-NAME was not concentration-dependent and reached a maximum of 40%, suggesting that basal NO outflow is only partially dependent on NOS activity. An eventual enhancement of NOS activity caused by KCl was disregarded because the activity of this enzyme measured in homogenates from mesenteric beds perfused with 70 mM KCl was significantly reduced. On the other hand, endothelium removal, employed as a negative control, almost abolished NOS activity, whereas the incubation with the Ca2+ ionophore A23187, employed as a positive control, induced an increase in NOS activity. It is concluded that in the mesenteric arterial bed of the rat, the contractile responses elicited by depolarization through KCl are coincident with a NOS-independent release of NO. This observation, which differs from the results obtained with noradrenaline, do not support the use of KCl as an alternative contractile agent whenever the participation of NO is under study. (C) 2000 Elsevier Science B.V.Fil: Mendizabal, Victoria Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Farmacológicas. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Investigaciones Farmacológicas; ArgentinaFil: Poblete, I.. Pontificia Universidad Católica de Chile; ChileFil: Lomniczi, A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; ArgentinaFil: Besuhli, Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; ArgentinaFil: Huidobro Toro, J. P.. Pontificia Universidad Católica de Chile; ChileFil: Adler, Edda. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Farmacológicas. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Investigaciones Farmacológicas; Argentin

    Probabilistic segmentation of the lumen from intravascular ultrasound radio frequency data

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    Abstract. Intravascular ultrasound (IVUS) is a catheter-based medical imaging technique that produces cross-sectional images of blood vessels. In this paper, we present a method for the segmentation of the luminal border using IVUS radio frequency (RF) data. Specifically, we parameterize the lumen contour using Fourier series. This contour is deformed by minimizing a cost function that is formulated using a probabilistic approach in which the a priori term is obtained using the prediction confidence of a Support Vector Machine classifier using features extracted from the RF signal. We evaluated the performance of our method by comparing our results with manual segmentations from two expert observers on 280 frames from eight 40 MHz IVUS sequences from rabbits and pigs. The performance was evaluated using the Dice similarity coefficient, coefficient of determination, and linear regressions of the lumen area for each frame. Our results indicate the feasibility of our method for the segmentation of the lumen from IVUS RF data
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