934 research outputs found

    The kindest cut: Enhancing the user experience of mobile tv through adequate zooming

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    The growing market of Mobile TV requires automated adaptation of standard TV footage to small size displays. Especially extreme long shots (XLS) depicting distant objects can spoil the user experience, e.g. in soccer content. Automated zooming schemes can improve the visual experience if the resulting footage meets user expectations in terms of the visual detail and quality but does not omit valuable context information. Current zooming schemes are ignorant of beneficial zoom ranges for a given target size when applied to standard definition TV footage. In two experiments 84 participants were able to switch between original and zoom enhanced soccer footage at three sizes - from 320x240 (QVGA) down to 176x144 (QCIF). Eye tracking and subjective ratings showed that zoom factors between 1.14 and 1.33 were preferred for all sizes. Interviews revealed that a zoom factor of 1.6 was too high for QVGA content due to low perceived video quality, but beneficial for QCIF size. The optimal zoom depended on the target display size. We include a function to compute the optimal zoom for XLS depending on the target device size. It can be applied in automatic content adaptation schemes and should stimulate further research on the requirements of different shot types in video coding

    Computational approaches to shed light on molecular mechanisms in biological processes

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    Computational approaches based on Molecular Dynamics simulations, Quantum Mechanical methods and 3D Quantitative Structure-Activity Relationships were employed by computational chemistry groups at the University of Milano-Bicocca to study biological processes at the molecular level. The paper reports the methodologies adopted and the results obtained on Aryl hydrocarbon Receptor and homologous PAS proteins mechanisms, the properties of prion protein peptides, the reaction pathway of hydrogenase and peroxidase enzymes and the defibrillogenic activity of tetracyclines. © Springer-Verlag 2007

    Uterine artery Doppler pulsatility index at 11-38 weeks in ICSI pregnancies with egg donation

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    BACKGROUND: Uterine artery Doppler pulsatility index (UtA-PI) may be different in pregnancies with egg donation (ICSI-ED) as compared to conceptions with autologous intra-cytoplasmatic sperm injection (autologous ICSI) and to spontaneous conceptions (SC). METHODS: One hundred and ninety-four pregnant women with different modes of conception (MC) were prospectively evaluated: 53 ICSI-ED, 36 autologous ICSI and 105 SC. To evaluate the effects of different MC on PI, multivariable linear regression (MLR) models predicting UtA-PI were fitted after adjustment for maternal age, body mass index, race, parity, smoking status and gestational age. RESULTS: In the first trimester, at MLR, autologous ICSI was not associated with a significantly different UtA-PI [estimate (EST) 0.01; 95% confidence interval (CI) -0.19, 0.2; P=0.9] when compared to SC. Conversely, MC by ICSI-ED was associated with lower first trimester UtA-PI (EST -0.32; CI -0.55, -0.08; P=0.01) when compared to SC. At MLR, MC by autologous ICSI and by ICSI-ED were not associated with significant differences in the second and third trimester UtA-PI when compared to SC. CONCLUSION: ICSI-ED conception presented lower UtA-PI when compared to SC at 11+0-13+6 weeks but not at later assessments. Correction of UtA-PI measurement specifying the origin of oocyte may be useful in first trimester screening

    Overpressurized bubbles versus voids formed in helium implanted annealed silicon

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    The formation of helium induced cavities in silicon is studied as a function of implant energy (10 and 40 keV) and dose (131015, 131016, and 531016 cm22). Specimens are analyzed after annealing (800 °C, 10 min) by transmission electron microscopy (TEM) and elastic recoil detection (ERD). Cavity nucleation and growth phenomena are discussed in terms of three different regimes depending on the implanted He content. For the low (131015 cm22) and high (531016 cm22) doses our results are consistent with the information in the literature. However, at the medium dose (131016 cm22), contrary to the gas release calculations which predict the formation of empty cavities, ERD analysis shows that a measurable fraction of the implanted He is still present in the annealed samples. In this case TEM analyses reveal that the cavities are surrounded by a strong strain field contrast and dislocation loops are generated. The results obtained are discussed on the basis of an alternative nucleation and growth behavior that allows the formation of bubbles in an overpressurized state irrespective of the competition with the gas release process

    Vitamin D deficiency and infertility : insights from in vitro fertilization cycles

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    Context: Vitamin D deficiency has been proven to affect fertility in mammals, but data in human is less convincing. In particular, data on in vitro fertilization (IVF), an attractive model to draw information on this topic, are sparse and conflicting.Objective: Our objective was to investigate IVF outcome in women with deficient 25-hydroxyvitamin D [25 (OH)D] serum levels (30 ng/mL) had the highest chances of pregnancy.Conclusions: VitaminDis an emerging factor influencing female fertility and IVF outcome. Additional studies are pressingly needed to confirm a causal relationship and to investigate the potential therapeutic benefits of vitamin D supplementation

    Effect of vitamin D supplementation on assisted reproduction technology (ART) outcomes and underlying biological mechanisms: protocol of a randomized clinical controlled trial. The "supplementation of vitamin D and reproductive outcome" (SUNDRO) study

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    Background Vitamin D plays an important role in human physiology and pathology. The receptor for vitamin D regulates 0.5-5% of the human genome. Accordingly, vitamin D insufficiency has been shown to increase the risk of several diseases. In recent years, based on growing evidence, on a role of vitamin D has been also postulated in reproductive health both in animals and humans, especially in female fertility female fertility. In vitro fertilization success was shown to be higher in women with appropriate reserves of vitamin D. However a causal relation has not been demonstrated and randomized controlled trials testing the effectiveness of vitamin D supplementation in IVF are warranted. Methods This is a multicenter randomized double blinded placebo controlled study aimed at determining the benefits of vitamin D [25(OH)D] supplementation in improving clinical pregnancy rate in women undergoing IVF. Eligible women with a serum level of 25-hydroxyvitamin D [25(OH)D] < 30 ng/ml will be randomized. Recruited women will be given the drug (either 600,000 IU of 25(OH) D or placebo in a single oral administration) at the time of randomization. Two centres will participate and the sample size (700 women) is foreseen to be equally distributed between the two. Patients will be treated according to standard IVF protocols. Discussion The primary aim of the study is the cumulative clinical pregnancy rate per oocyte retrieval. Clinical pregnancy is defined as the presence of at least one intrauterine gestational sac with viable foetus at first ultrasound assessment (3 weeks after a positive human chorionic gonadotropin [hCG] assessment). Secondary outcomes include: 1) clinical and embryological variables; 2) oocyte and endometrium quality at a molecular level. To investigate this latter aspect, samples of cumulus cells, follicular and endometrial fluids will be obtained from a subgroup of 50 age-matched good-prognosis cases and controls

    Molecular-dynamics-simulation-guided membrane engineering allows the increase of membrane fatty acid chain length in Saccharomyces cerevisiae

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    The use of lignocellulosic-based fermentation media will be a necessary part of the transition to a circular bio-economy. These media contain many inhibitors to microbial growth, including acetic acid. Under industrially relevant conditions, acetic acid enters the cell predominantly through passive diffusion across the plasma membrane. The lipid composition of the membrane determines the rate of uptake of acetic acid, and thicker, more rigid membranes impede passive diffusion. We hypothesized that the elongation of glycerophospholipid fatty acids would lead to thicker and more rigid membranes, reducing the influx of acetic acid. Molecular dynamics simulations were used to predict the changes in membrane properties. Heterologous expression of Arabidopsis thaliana genes fatty acid elongase 1 (FAE1) and glycerol-3-phosphate acyltransferase 5 (GPAT5) increased the average fatty acid chain length. However, this did not lead to a reduction in the net uptake rate of acetic acid. Despite successful strain engineering, the net uptake rate of acetic acid did not decrease. We suggest that changes in the relative abundance of certain membrane lipid headgroups could mitigate the effect of longer fatty acid chains, resulting in a higher net uptake rate of acetic acid
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