294 research outputs found

    ActiveStereoNet: End-to-End Self-Supervised Learning for Active Stereo Systems

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    In this paper we present ActiveStereoNet, the first deep learning solution for active stereo systems. Due to the lack of ground truth, our method is fully self-supervised, yet it produces precise depth with a subpixel precision of 1/30th1/30th of a pixel; it does not suffer from the common over-smoothing issues; it preserves the edges; and it explicitly handles occlusions. We introduce a novel reconstruction loss that is more robust to noise and texture-less patches, and is invariant to illumination changes. The proposed loss is optimized using a window-based cost aggregation with an adaptive support weight scheme. This cost aggregation is edge-preserving and smooths the loss function, which is key to allow the network to reach compelling results. Finally we show how the task of predicting invalid regions, such as occlusions, can be trained end-to-end without ground-truth. This component is crucial to reduce blur and particularly improves predictions along depth discontinuities. Extensive quantitatively and qualitatively evaluations on real and synthetic data demonstrate state of the art results in many challenging scenes.Comment: Accepted by ECCV2018, Oral Presentation, Main paper + Supplementary Material

    Synthesis of Silver Nanoparticles Using Curcumin-Cyclodextrins Loaded into Bacterial Cellulose-Based Hydrogels for Wound Dressing Applications.

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    Chronic wounds are often recalcitrant to treatment because of high microbial bioburden and the problem of microbial resistance. Silver is a broad-spectrum natural antimicrobial agent with wide applications extending to proprietary wound dressings. Recently, silver nanoparticles have attracted attention in wound management. In the current study, the green synthesis of nanoparticles was accomplished using a natural reducing agent, curcumin, which is a natural polyphenolic compound that is well-known as a wound-healing agent. The hydrophobicity of curcumin was overcome by its microencapsulation in cyclodextrins. This study demonstrates the production, characterization of silver nanoparticles using aqueous curcumin:hydroxypropyl-β-cyclodextrin complex and loading them into bacterial cellulose hydrogel with moist wound-healing properties. These silver nanoparticle-loaded bacterial cellulose hydrogels were characterized for wound-management applications. In addition to high cytocompatibility, these novel dressings exhibited antimicrobial activity against three common wound-infecting pathogenic microbes , , and

    Meaningful time for professional growth or a waste of time? A study in five countries on teachers’ experiences within master’s dissertation/thesis work

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    The relationship between master’s thesis work and teachers’ professional development has rarely been explored empirically, yet. Drawing upon a larger study, this paper investigates how teachers who were studying for or who have recently graduated from Master of Education programmes offered in five countries – Poland, Portugal, England, Latvia, Romania – perceive the usefulness of dissertation/thesis work for their professional development and how they attempt to use their MA research results in their (future) teaching practice. Results suggest that although most respondents recognized their MA dissertation/thesis work as having a positive impact on their professional development by enhancing their professionalism, personal development and growth, and understanding the relationship between research and practice, they were less confident about the use of MA research findings in their (future) workplaces. These results are discussed in the context of current challenges regarding master’s level education for teachers, national governments’ educational policies, and the relationship between research, teachers’ practices and professional development

    Diversity of hard-bottom fauna relative to environmental gradients in Kongsfjorden, Svalbard

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    A baseline study of hard-bottom zoobenthos in relation to environmental gradients in Kongsfjorden, a glacial fjord in Svalbard, is presented, based on collections from 1996 to 1998. The total species richness in 62 samples from 0 to 30 m depth along five transects was 403 species. Because 32 taxa could not be identified to species level and because 11 species are probably new to science, the total number of identified species was 360. Of these, 47 species are new for Svalbard waters. Bryozoa was the most diverse group. Biogeographic composition revealed features of both Arctic and sub-Arctic properties of the fauna. Species richness, frequency of species occurrence, mean abundance and biomass generally decreased towards the tidal glaciers in inner Kongsfjorden. Among eight environmental factors, depth was most important for explaining variance in the composition of the zoobenthos. The diversity was consistently low at shallow depths, whereas the non-linear patterns of species composition of deeper samples indicated a transitional zone between surface and deeper water masses at 15–20 m depth. Groups of “colonial” and “non-colonial” species differed in diversity, biogeographic composition and distribution by location and depth as well as in relation to other environmental factors. “Non-colonial” species made a greater contribution than “colonial” species to total species richness, total occurrence and biomass in samples, and were more influenced by the depth gradient. Biogeographic composition was sensitive to variation of zoobenthic characteristics over the studied depth range. A list of recorded species and a description of sampling sites are presented

    Production and Characterisation of Bacterial Cellulose Hydrogels Loaded with Curcumin Encapsulated in Cyclodextrins as Wound Dressings

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    Natural bioactive materials with wound healing properties such as curcumin are attracting interest due to the emergence of resistant bacterial strains. The hydrophobicity of curcumin has been counteracted by using solubility enhancing cyclodextrins. Hydrogels facilitate wound healing due to unique properties and 3D network structures which allows encapsulation of healing agents. In this study, biosynthetic cellulose produced by Gluconacetobacter xylinus (ATCC 23770) was loaded with water soluble curcumin:hydroxypropyl-β-cyclodextrin supramolecular inclusion complex produced by a solvent evaporation method to synthesise hydrogel dressings. The ratios of solvents to solubilise curcumin and hydroxypropyl-β-cyclodextrin were tested for the production of the inclusion complex with optimum encapsulation efficacy. The results confirmed that hydroxypropyl-β-cyclodextrin enhanced the aqueous solubility of curcumin and allowed loading into bacterial cellulose hydrogels. These hydrogels were characterised for wound management applications and exhibited haemocompatability, cytocompatability, anti-staphylococcal and antioxidant abilities and therefore support the potential use of the curcumin:hydroxypropyl-β-cyclodextrin-loaded-bacterial cellulose as hydrogel dressings

    Forensic Engineering of Advanced Polymeric Materials. Part 1 –Degradation Studies of Polylactide Blends with Atactic Poly[(R,S)-3-hydroxybutyrate] in Paraffin

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    The degradation of the advanced polymeric materials: blends of polylactide with poly[(R,S)-3-hydroxybutyrate] was studied in paraffin (an ingredient used in cosmetics) and compared with the degradation of pure poly[(R,S)-3-hydroxybutyrate]. The interaction between the polymeric materials studied and the paraffin was monitored during the degradation experiments, and the effects of this interaction were reported. Gel permeation chromatography, atomic force microscopy, electrospray mass spectrometry, nuclear magnetic resonance, differential scanning calorimetry and thermal gravimetric analysis revealed that degradation of the investigated materials occurs in the presence of paraffin. In the blends, poly[(R,S)-3-hydroxybutyrate] content was found to extend the disintegration time, and for the blends with good miscibility, reduced the degradation rate in the first step of degradation

    Optical techniques for 3D surface reconstruction in computer-assisted laparoscopic surgery

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    One of the main challenges for computer-assisted surgery (CAS) is to determine the intra-opera- tive morphology and motion of soft-tissues. This information is prerequisite to the registration of multi-modal patient-specific data for enhancing the surgeon’s navigation capabilites by observ- ing beyond exposed tissue surfaces and for providing intelligent control of robotic-assisted in- struments. In minimally invasive surgery (MIS), optical techniques are an increasingly attractive approach for in vivo 3D reconstruction of the soft-tissue surface geometry. This paper reviews the state-of-the-art methods for optical intra-operative 3D reconstruction in laparoscopic surgery and discusses the technical challenges and future perspectives towards clinical translation. With the recent paradigm shift of surgical practice towards MIS and new developments in 3D opti- cal imaging, this is a timely discussion about technologies that could facilitate complex CAS procedures in dynamic and deformable anatomical regions

    Placental Growth Factor Contributes to Micro-Vascular Abnormalization and Blood-Retinal Barrier Breakdown in Diabetic Retinopathy

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    OBJECTIVE: There are controversies regarding the pro-angiogenic activity of placental growth factor (PGF) in diabetic retinopathy (DR). For a better understanding of its role on the retina, we have evaluated the effect of a sustained PGF over-expression in rat ocular media, using ciliary muscle electrotransfer (ET) of a plasmid encoding rat PGF-1 (pVAX2-rPGF-1). MATERIALS AND METHODS: pVAX2-rPGF-1 ET in the ciliary muscle (200 V/cm) was achieved in non diabetic and diabetic rat eyes. Control eyes received saline or naked plasmid ET. Clinical follow up was carried out over three months using slit lamp examination and fluorescein angiography. After the control of rPGF-1 expression, PGF-induced effects on retinal vasculature and on the blood-external barrier were evaluated respectively by lectin and occludin staining on flat-mounts. Ocular structures were visualized through histological analysis. RESULTS: After fifteen days of rPGF-1 over-expression in normal eyes, tortuous and dilated capillaries were observed. At one month, microaneurysms and moderate vascular sprouts were detected in mid retinal periphery in vivo and on retinal flat-mounts. At later stages, retinal pigmented epithelial cells demonstrated morphological abnormalities and junction ruptures. In diabetic retinas, PGF expression rose between 2 and 5 months, and, one month after ET, rPGF-1 over-expression induced glial activation and proliferation. CONCLUSION: This is the first demonstration that sustained intraocular PGF production induces vascular and retinal changes similar to those observed in the early stages of diabetic retinopathy. PGF and its receptor Flt-1 may therefore be looked upon as a potential regulatory target at this stage of the disease

    Degradability of cross-linked polyurethanes based on synthetic polyhydroxybutyrate and modified with polylactide

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    In many areas of application of conventional non-degradable cross-linked polyurethanes (PUR), there is a need for their degradation under the influence of specific environmental factors. It is practiced by incorporation of sensitive to degradation compounds (usually of natural origin) into the polyurethane structure, or by mixing them with polyurethanes. Cross-linked polyurethanes (with 10 and 30%wt amount of synthetic poly([R,S]-3-hydroxybutyrate) (R,S-PHB) in soft segments) and their physical blends with poly([d,l]-lactide) (PDLLA) were investigated and then degraded under hydrolytic (phosphate buffer solution) and oxidative (CoCl2/H2O2) conditions. The rate of degradation was monitored by changes of samples mass, morphology of surface and their thermal properties. Despite the small weight losses of samples, the changes of thermal properties of polymers and topography of their surface indicated that they were susceptible to gradual degradation under oxidative and hydrolytic conditions. Blends of PDLLA and polyurethane with 30 wt% of R,S-PHB in soft segments and PUR/PDLLA blends absorbed more water and degraded faster than polyurethane with low amount of R,S-PHB
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