3,138 research outputs found

    Photorealistic Audio-driven Video Portraits

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    Video portraits are common in a variety of applications, such as videoconferencing, news broadcasting, and virtual education and training. We present a novel method to synthesize photorealistic video portraits for an input portrait video, automatically driven by a person’s voice. The main challenge in this task is the hallucination of plausible, photorealistic facial expressions from input speech audio. To address this challenge, we employ a parametric 3D face model represented by geometry, facial expression, illumination, etc., and learn a mapping from audio features to model parameters. The input source audio is first represented as a high-dimensional feature, which is used to predict facial expression parameters of the 3D face model. We then replace the expression parameters computed from the original target video with the predicted one, and rerender the reenacted face. Finally, we generate a photorealistic video portrait from the reenacted synthetic face sequence via a neural face renderer. One appealing feature of our approach is the generalization capability for various input speech audio, including synthetic speech audio from text-to-speech software. Extensive experimental results show that our approach outperforms previous general-purpose audio-driven video portrait methods. This includes a user study demonstrating that our results are rated as more realistic than previous methods

    Example-Guided Style-Consistent Image Synthesis from Semantic Labeling

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    Example-guided image synthesis aims to synthesize an image from a semantic label map and an exemplary image indicating style. We use the term “style” in this problem to refer to implicit characteristics of images, for example: in portraits “style” includes gender, racial identity, age, hairstyle; in full body pictures it includes clothing; in street scenes it refers to weather and time of day and such like. A semantic label map in these cases indicates facial expres- sion, full body pose, or scene segmentation. We propose a solution to the example-guided image synthesis problem us- ing conditional generative adversarial networks with style consistency. Our key contributions are (i) a novel style consistency discriminator to determine whether a pair of im- ages are consistent in style; (ii) an adaptive semantic con- sistency loss; and (iii) a training data sampling strategy, for synthesizing style-consistent results to the exemplar. We demonstrate the efficiency of our method on face, dance and street view synthesis tasks

    New chemolysis for urological calcium phosphate calculi – a study in vitro

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    BACKGROUND: Advances in techniques have left very few indications for open surgical extraction of urinary stones currently. These advances notwithstanding, the search continues for medical approaches to urinary stone management. In this study, we perform an in vitro study analyzing the efficiency and prospect of two new complex solutions in urological calcium phosphate calculi dissolution. METHODS: Eighteen stones composed mainly of calcium phosphates were taken from patients who underwent kidney stone surgery. These stones were large enough (weight range 0.514–0.928 g) to be fragmented and matched equally into six groups. Chemolysis of phosphate stones was done with six different solvents and was repeated 3 times with 6 stones for each solution. At 24, 48 and 72 h, reduction in weight, percentage weight change, and dissolution rate; the dissolution rates at pH 5.0, 7.0 and 8.5 for each solution, using different cations (Na(+), K(+ )or Ca(2+)), according to different dilutions (1:1, 1:2, 1:3, 1:4) of S1 and S2 were simultaneously determined. RESULTS: Calcium phosphate calculi were poorly dissolved by Phys and Art, and they had a low dissolution rate in pH 8.5 EDTA. The most effective solutions were S1, S2 and R, with 72 h mean dissolution rates: 5.75 ± 0.44 mg/hr (S1), 5.2 ± 0.63 mg/hr (S2), 4.55 ± 0.46 mg/hr (R) ([Image: see text] ± s, p < 0.01 R, S1 and S2 vs Phys, Art and EDTA; p < 0.05, S1 vs R, LSD-test). The mean percentage weight loss at 72 h was: 52.1 ± 15.75 % (S1), 44.4 ± 7.37 % (S2) and 40.5 ± 3.67 % (R) ([Image: see text] ± s, p < 0.01 R, S1 and S2 vs Phys, Art and EDTA, LSD-test). Diluted twice, S1 and S2 had even better effectiveness than their initial solution. The additive of Na(+), K(+ )or Ca(2+ )greatly reduced the dissolution rates of S1, S2. CONCLUSION: Our data indicate that test solutions S1 and S2 are effective solvents in the chemolysis of calcium phosphate stones. At twice dilutions, these solutions are even more useful in the treatment of stone disease

    MEASUREMENT OF SOLID SLURRY FLOW VIA CORRELATION OF ELECTROMAGNETIC FLOW METER, ELECTRICAL RESISTANCE TOMOGRAPHY AND MECHANISTIC MODELLING

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    The study presented here was carried out to obtain the actual solids flow rate by the combination of electrical resistance tomography and electromagnetic flow meter. A new in-situ measurement method based on measurements of the Electromagnetic Flow Meters (EFM) and Electrical Resistance Tomography (ERT) to study the flow rates of individual phases in a vertical flow was proposed. The study was based on laboratory experiments that were carried out with a 50 mm vertical flow rig for a number of sand concentrations and different mixture velocities. A range of sand slurries with median particle size from 212 mu m to 355 mu m was tested. The solid concentration by volume covered was 5% and 15%, and the corresponding density of 5% was 1078 kg/m(3) and of 15% was 1238 kg/m(3). The flow velocity was between 1.5 m/s and 3.0 m/s. A total of 6 experimental tests were conducted. The equivalent liquid model was adopted to validate in-situ volumetric solids fraction and calculate the slip velocity. The results show that the ERT technique can be used in conjunction with an electromagnetic flow meter as a way of measurement of slurry flow rate in a vertical pipe flow. However it should be emphasized that the EFM results must be treated with reservation when the flow pattern at the EFM mounting position is a non-homogenous flow. The flow rate obtained by the EFM should be corrected considering the slip velocity and the flow pattern

    The ultrafast dynamics and conductivity of photoexcited graphene at different Fermi energies

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    This is the final version. A vailable from the American Association for the Advancement of Science via the DOI in this record.For many of the envisioned optoelectronic applications of graphene it is crucial to understand the sub-picosecond carrier dynamics immediately following photoexcitation, as well as the effect on the electrical conductivity - the photoconductivity. Whereas these topics have been studied using various ultrafast experiments and theoretical approaches, controversial and incomplete explanations have been put forward concerning the sign of the photoconductivity, the occurrence and significance of the creation of additional electron-hole pairs, and, in particular, how the relevant processes depend on Fermi energy. Here, we present a unified and intuitive physical picture of the ultrafast carrier dynamics and the photoconductivity, combining optical pump - terahertz probe measurements on a gate-tunable graphene device, with numerical calculations using the Boltzmann equation. We distinguish two types of ultrafast photo-induced carrier heating processes: At low (equilibrium) Fermi energy (EF≲E_{\rm F} \lesssim 0.1 eV for our experiments) broadening of the carrier distribution involves interband transitions - interband heating. At higher Fermi energy (EF≳E_{\rm F} \gtrsim 0.15 eV) broadening of the carrier distribution involves intraband transitions - intraband heating. Under certain conditions, additional electron-hole pairs can be created (carrier multiplication) for low EFE_{\rm F}, and hot carriers (hot-carrier multiplication) for higher EFE_{\rm F}. The resultant photoconductivity is positive (negative) for low (high) EFE_{\rm F}, which originates from the effect of the heated carrier distributions on the screening of impurities, consistent with the DC conductivity being mostly due to impurity scattering. The importance of these insights is highlighted by a discussion of the implications for graphene photodetector applications.European Union Horizon 2020Severo Ochoa Programme for Centres of Excellence in R&DMineco grants Ramon y CajalSpanish Ministry of Economy and CompetitivenessGovernment of CataloniaEuropean Research Council StG CarbonLightGerman Research FoundationState Research Centre for Innovative and Emerging Materials and the Graduate School of Excellence Materials Science in Mainz (MAINZ)Engineering and Physical Sciences Research Council (EPSRC)Minec

    Deep generative modeling for single-cell transcriptomics.

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    Single-cell transcriptome measurements can reveal unexplored biological diversity, but they suffer from technical noise and bias that must be modeled to account for the resulting uncertainty in downstream analyses. Here we introduce single-cell variational inference (scVI), a ready-to-use scalable framework for the probabilistic representation and analysis of gene expression in single cells ( https://github.com/YosefLab/scVI ). scVI uses stochastic optimization and deep neural networks to aggregate information across similar cells and genes and to approximate the distributions that underlie observed expression values, while accounting for batch effects and limited sensitivity. We used scVI for a range of fundamental analysis tasks including batch correction, visualization, clustering, and differential expression, and achieved high accuracy for each task

    Mechanisms of Epithelial-Mesenchymal Transition of Peritoneal Mesothelial Cells During Peritoneal Dialysis

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    A growing body of evidence indicates that epithelial-mesenchymal transition (EMT) of human peritoneal mesothelial cells (HPMC) may play an important role in the development and progression of peritoneal fibrosis during long-term peritoneal dialysis (PD) leading to failure of peritoneal membrane function. Here, we review our own observations and those of others on the mechanisms of EMT of HPMC and suggest potential therapeutic strategies to prevent EMT and peritoneal fibrosis during long-term PD. We found that high glucose and H2O2 as well as transforming growth factor-β1 (TGF-β1) induced EMT in HPMC and that high glucose-induced EMT was blocked not only by inhibition of TGF-β1 but also by antioxidants or inhibitors of mitogen-activated protein kinases (MAPK). Since MAPKs are downstream target molecules of reactive oxygen species (ROS), these data suggest that high glucose-induced generation of ROS and subsequent MAPK activation mediate high glucose-induced EMT in HPMC. We and others also observed that bone morphogenetic protein-7 (BMP-7) prevented EMT in HPMC. Glucose degradation products (GDP) were shown to play a role in inducing EMT. Involvement of a mammalian target of rapamycin (mTOR) in TGF-β1-induced EMT has also been proposed in cultured HPMC. A better understanding of the precise mechanisms involved in EMT of HPMC may provide new therapeutic strategies for inhibiting peritoneal fibrosis in long-term PD patients

    Turo (Qi Dance) Training Attenuates Psychological Symptoms and Sympathetic Activation Induced by Mental Stress in Healthy Women

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    Vagal withdrawal and sympathetic overactivity accompany various types of stress. Qi training is reported to reduce sympathetic hyper-reactivity in a stressful situation. Turo, which is a type of dance that uses the Meridian Qi System, may reduce the psychological symptoms induced by an imbalance of the autonomic nervous system (ANS). We observed whether Turo training alters psychopathological and psychological symptoms using the Symptom Checklist 90-Revision (SCL-90-R) and examined whether it attenuates the stress response to mental stress in healthy adolescent females using the power spectrum analysis of heart rate variability (HRV). Twenty-one subjects received Turo training and 27 subjects were trained with mimicking movements. The SCL-90-R was measured before and after the 2-month training period. Heart rate (HR), total power (TP) and the LF/HF ratio of HRV were compared between the Turo and control groups during and after mental stress. The somatization and hostility subscales of the SCL-90-R of the Turo group were significantly lower than those of the control group after 2 months. The increases in HR and the LF/HF ratio of HRV induced by the stress test were significantly lower in the Turo group than in the control group. The TP of the Turo group was significantly higher than that of the control group. The psychological symptoms and sympathetic activation induced by the artificial stress were significantly reduced by the Turo training. These findings suggest that Turo training can play a critical role in attenuating psychological symptoms and stress-induced sympathetic activation

    METHODS - A randomised controlled trial of METhotrexate to treat Hand Osteoarthritis with Synovitis: study protocol for a randomised controlled trial

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    Background: Hand osteoarthritis is a common and disabling problem without effective therapies. Accumulating evidence suggests the role of local inflammation in causing pain and structural progression in hand osteoarthritis, and hand osteoarthritis with synovitis is a commonly encountered clinical phenotype. Methotrexate is a well-established, low-cost, and effective treatment for inflammatory arthritis with a well-described safety profile. The aim of this multicentre, randomised, double-blind, placebo-controlled trial is to determine whether methotrexate reduces pain over 6 months in patients with hand osteoarthritis and synovitis.Methods: Ninety-six participants with hand osteoarthritis and synovitis will be recruited through the Osteoarthritis Clinical Trial Network (Melbourne, Hobart, Adelaide, and Perth), and randomly allocated in a 1:1 ratio to receive either methotrexate 20 mg or identical placebo once weekly for 6 months. The primary outcome is pain reduction (assessed by 100 mm visual analogue scale) at 6 months. The secondary outcomes include changes in physical function and quality of life assessed using Functional Index for Hand Osteoarthritis, Australian Canadian Osteoarthritis Hand Index, Health Assessment Questionnaire, Michigan Hand Outcomes Questionnaire, Short-Form-36, tender and swollen joint count, and grip strength, and structural progression assessed using progression of synovitis and bone marrow lesions from magnetic resonance imaging and radiographic progression at 6 months. Adverse events will be recorded. The primary analysis will be by intention to treat, including all participants in their randomised groups.Discussion: This study will provide high-quality evidence to address whether methotrexate has an effect on reducing pain over 6 months in patients with hand osteoarthritis and synovitis, with major clinical and public health importance. While a positive trial will inform international clinical practice guidelines for the management of hand osteoarthritis, a negative trial would be highly topical and change current trends in clinical practice

    Investigation of heat transfer enhancement in a triple tube latent heat storage system using circular fins with inline and staggered arrangements

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    Copyright: © 2021 by the authors. Inherent fluctuations in the availability of energy from renewables, particularly solar, remain a substantial impediment to their widespread deployment worldwide. Employing phasechange materials (PCMs) as media, saving energy for later consumption, offers a promising solution for overcoming the problem. However, the heat conductivities of most PCMs are limited, which severely limits the energy storage potential of these materials. This study suggests employing circular fins with staggered distribution to achieve improved thermal response rates of PCM in a vertical triple-tube heat exchanger involving two opposite flow streams of the heat-transfer fluid (HTF). Since heat diffusion is not the same at various portions of the PCM unit, different fin configurations, fin dimensions and HTF flow boundary conditions were explored using computational studies of melting in the PCM triple-tube system. Staggered configuration of fin distribution resulted in significant increases in the rates of PCM melting. The results indicate that the melting rate and heat charging rate could be increased by 37.2 and 59.1%, respectively, in the case of staggered distribution. Furthermore, the use of lengthy fins with smaller thickness in the vertical direction of the storage unit resulted in a better positive role of natural convection; thus, faster melting rates were achieved. With fin dimensions of 0.666 mm × 15 mm, the melting rate was found to be increased by 23.6%, when compared to the base case of 2 mm × 5 mm. Finally, it was confirmed that the values of the Reynolds number and inlet temperatures of the HTF had a significant impact on melting time savings when circular fins of staggered distribution were included
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