257 research outputs found

    Single-frame Regularization for Temporally Stable CNNs

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    Convolutional neural networks (CNNs) can model complicated non-linear relations between images. However, they are notoriously sensitive to small changes in the input. Most CNNs trained to describe image-to-image mappings generate temporally unstable results when applied to video sequences, leading to flickering artifacts and other inconsistencies over time. In order to use CNNs for video material, previous methods have relied on estimating dense frame-to-frame motion information (optical flow) in the training and/or the inference phase, or by exploring recurrent learning structures. We take a different approach to the problem, posing temporal stability as a regularization of the cost function. The regularization is formulated to account for different types of motion that can occur between frames, so that temporally stable CNNs can be trained without the need for video material or expensive motion estimation. The training can be performed as a fine-tuning operation, without architectural modifications of the CNN. Our evaluation shows that the training strategy leads to large improvements in temporal smoothness. Moreover, for small datasets the regularization can help in boosting the generalization performance to a much larger extent than what is possible with na\"ive augmentation strategies

    Dietary enrichment of apolipoprotein E-deficient mice with extra virgin olive oil in combination with seal oil inhibits atherogenesis

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    <p>Abstract</p> <p>Background</p> <p>In this study we investigated the antiatherogenic effect of dietary enrichment of a combination of extra virgin olive oil (EVO) and seal oil on apolipoprotein E-deficient (apoE<sup>-/-</sup>).</p> <p>Methods</p> <p>Six-week-old female and male apoE<sup>-/- </sup>mice were for 12 weeks fed a lipid rich diet containing 19.5% fat and 1.25% cholesterol without any supplement, with 1% (wt/wt) mixture of extra virgin olive and seal oil (EVO/n-3), or 1% corn oil, respectively.</p> <p>Results</p> <p>Supplementation with the combination of EVO/n-3 significantly reduced atherosclerotic lesion formation in the aortic arch, thoracoabdominal, and total aorta of female apoE<sup>-/-</sup>mice. The effect was less pronounced in male mice and significant reduction was only observed in the thoracoabdominal region of the aorta. There were no differences or changes in dietary intake or body weight gain. However, compared to the other groups, plasma levels of triglycerides were reduced in both female and male mice fed the EVO/n-3 mixture. Male mice on both treatments showed reduced plasma cholesterol compared to the control mice after 12 weeks on diet.</p> <p>Conclusion</p> <p>Dietary supplementation of a marine/olive oil combination inhibits atherosclerotic lesion formation in the female apoE<sup>-/- </sup>mice by antithrombotic, antihypertriglyceridemic, and antioxidant effects.</p

    Dietary enrichment of apolipoprotein E-deficient mice with extra virgin olive oil in combination with seal oil inhibits atherogenesis

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    Background: In this study we investigated the antiatherogenic effect of dietary enrichment of a combination of extra virgin olive oil (EVO) and seal oil on apolipoprotein E-deficient (apoE(-/-)). Methods: Six-week-old female and male apoE(-/-) mice were for 12 weeks fed a lipid rich diet containing 19.5% fat and 1.25% cholesterol without any supplement, with 1% (wt/wt) mixture of extra virgin olive and seal oil (EVO/n-3), or 1% corn oil, respectively. Results: Supplementation with the combination of EVO/n-3 significantly reduced atherosclerotic lesion formation in the aortic arch, thoracoabdominal, and total aorta of female apoE(-/-) mice. The effect was less pronounced in male mice and significant reduction was only observed in the thoracoabdominal region of the aorta. There were no differences or changes in dietary intake or body weight gain. However, compared to the other groups, plasma levels of triglycerides were reduced in both female and male mice fed the EVO/n-3 mixture. Male mice on both treatments showed reduced plasma cholesterol compared to the control mice after 12 weeks on diet. Conclusion: Dietary supplementation of a marine/olive oil combination inhibits atherosclerotic lesion formation in the female apoE(-/-) mice by antithrombotic, antihypertriglyceridemic, and antioxidant effects

    Structural and functional analyses of Rubisco from arctic diatom species reveal unusual posttranslational modifications

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    The catalytic performance of the major CO2-assimilating enzyme, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), restricts photosynthetic productivity. Natural diversity in the catalytic properties of Rubisco indicates possibilities for improvement. Oceanic phytoplankton contain some of the most efficient Rubisco enzymes, and diatoms in particular are responsible for a significant proportion of total marine primary production as well as being a major source of CO2 sequestration in polar cold waters. Until now, the biochemical properties and three-dimensional structures of Rubisco from diatoms were unknown. Here, diatoms from Arctic waters were collected, cultivated and analyzed for their CO2 fixing capability. We characterized the kinetic properties of five, and determined the crystal structures of four Rubiscos selected for their high CO2-fixing efficiency. The DNA sequences of the rbcL and rbcS genes of the selected diatoms were similar, reflecting their close phylogenetic relationship. The Vmax and KM for the oxygenase and carboxylase activities at 25°C and the specificity factors (Sc /o) at 15, 25 and 35°C, were determined. The Sc/o values were high, approaching those of mono- and dicot plants, thus exhibiting good selectivity for CO2 relative to O2. Structurally, diatom Rubiscos belong to Form I C/D, containing small subunits characterised by a short βA-βB loop and a carboxy-terminal extension that forms a β- hairpin structure (βE-βF loop). Of note, the diatom Rubiscos featured a number of posttranslational modifications of the large subunit, including 4-hydroxy-proline, betahydroxyleucine, hydroxylated, and nitrosylated cysteine, mono-, and di-hydroxylated lysine, and tri-methylated lysine. Our studies suggest adaptation toward achieving efficient CO2-fixation in Arctic diatom Rubiscos
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