324 research outputs found

    Nanogenerator comprising piezoelectric semiconducting nanostructures and Schottky conductive contacts

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    A semiconducting device includes a substrate, a piezoelectric wire, a structure, a first electrode and a second electrode. The piezoelectric wire has a first end and an opposite second end and is disposed on the substrate. The structure causes the piezoelectric wire to bend in a predetermined manner between the first end and the second end so that the piezoelectric wire enters a first semiconducting state. The first electrode is coupled to the first end and the second electrode is coupled to the second end so that when the piezoelectric wire is in the first semiconducting state, an electrical characteristic will be exhibited between the first electrode and the second electrode

    Piezoelectric and Semiconducting Coupled Nanogenerators

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    An electrical generator includes a substrate, a semiconductor piezoelectric structure having a first end and an opposite second end disposed adjacent to the substrate, a first conductive contact and a second conductive contact. The structure bends when a force is applied adjacent to the first end, thereby causing an electrical potential difference to exist between a first side and a second side of the structure. The first conductive contact is in electrical communication with the first end and includes a material that creates a Schottky barrier between a portion of the first end of the structure and the first conductive contact. The first conductive contact is also disposed relative to the structure in a position so that the Schottky barrier is forward biased when the structure is deformed, thereby allowing current to flow from the first conductive contact into the first end

    Development of a face recognition system and its intelligent lighting compensation method for dark-field application

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    A face recognition system which uses 3D lighting estimation and optimal lighting compensation for dark-field application is proposed. To develop the proposed system, which can realize people identification in a near scene dark-field environment, a light-emitting diode (LED) overhead light, eight LED wall lights, a visible light binocular camera, and a control circuit are used. First, 68 facial landmarks are detected and their coordinates in both image as well as camera coordinate systems are computed. Second, a 3D morphable model (3DMM) is developed after considering facial shadows, and a transformation matrix between the 3DMM and camera coordinate systems is estimated. Third, to assess lighting uniformity, 30 evaluation points are selected from the face. Sequencing computations of LED radiation intensity, ray reflection luminance, camera response, and face lighting uniformity are then carried out. Ray occlusion is processed using a simplified 3D face model. Fourth, an optimal lighting compensation is realized: the overhead light is used for flood lighting, and the wall lights are employed as meticulous lighting. A genetic algorithm then is used to identify the optimal lighting of the wall lights. Finally, an Eigenface method is used for face recognition. The results show that our system and method can improve face recognition accuracy by >10% compared to traditional recognition methods

    A Drosophila protein-interaction map centered on cell-cycle regulators

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    BACKGROUND: Maps depicting binary interactions between proteins can be powerful starting points for understanding biological systems. A proven technology for generating such maps is high-throughput yeast two-hybrid screening. In the most extensive screen to date, a Gal4-based two-hybrid system was used recently to detect over 20,000 interactions among Drosophila proteins. Although these data are a valuable resource for insights into protein networks, they cover only a fraction of the expected number of interactions. RESULTS: To complement the Gal4-based interaction data, we used the same set of Drosophila open reading frames to construct arrays for a LexA-based two-hybrid system. We screened the arrays using a novel pooled mating approach, initially focusing on proteins related to cell-cycle regulators. We detected 1,814 reproducible interactions among 488 proteins. The map includes a large number of novel interactions with potential biological significance. Informative regions of the map could be highlighted by searching for paralogous interactions and by clustering proteins on the basis of their interaction profiles. Surprisingly, only 28 interactions were found in common between the LexA- and Gal4-based screens, even though they had similar rates of true positives. CONCLUSIONS: The substantial number of new interactions discovered here supports the conclusion that previous interaction mapping studies were far from complete and that many more interactions remain to be found. Our results indicate that different two-hybrid systems and screening approaches applied to the same proteome can generate more comprehensive datasets with more cross-validated interactions. The cell-cycle map provides a guide for further defining important regulatory networks in Drosophila and other organisms

    Piezoelectric Nanogenerators for Self-Powered Nanodevices

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    ©2008 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or distribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder.Although nanodevices fabricated using nanomaterials such as nanotubes or nanowires offer low power consumption, powering them can still be challenging. Adding a battery could sufficiently increase their size to inhibit their application. Developing miniature power packages and self-powering methods will be key to their use in a variety of applications, including those for wireless sensing; in-vivo, real-time, and implantable biological devices; environmental monitoring; and personal electronics. Consequently, researchers are developing innovative nanotechnologies to convert various forms of energy (such as solar energy) into electric energy for low-power nanodevices. In our own work, we’ve used piezoelectric zinc-oxide nanowire (ZnO NW) arrays to demonstrate a novel approach for converting nanoscale mechanical energy into electric energy. Here, we review the fundamental principle behind the nanogenerator, present an approach for improving its performance, and discuss some of the challenges we face in pushing this technology to reach its potential

    Structural Diversity of Ultralong CDRH3s in Seven Bovine Antibody Heavy Chains

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    Antigen recognition by mammalian antibodies represents the most diverse setting for protein-protein interactions, because antibody variable regions contain exceptionally diverse variable gene repertoires of DNA sequences containing combinatorial, non-templated junctional mutational diversity. Some animals use additional strategies to achieve structural complexity in the antibody combining site, and one of the most interesting of these is the formation of ultralong heavy chain complementarity determining region 3 loops in cattle. Repertoire sequencing studies of bovine antibody heavy chain variable sequences revealed that bovine antibodies can contain heavy chain complementarity determining region 3 (CDRH3) loops with 60 or more amino acids, with complex structures stabilized by multiple disulfide bonds. It is clear that bovine antibodies can achieve long, peculiarly structured CDR3s, but the range of diversity and complexity of those structures is poorly understood. We determined the atomic resolution structure of seven ultralong bovine CDRH3 loops. The studies, combined with five previous structures, reveal a large diversity of cysteine pairing variations, and highly diverse globular domains

    A reporting tool for practice guidelines in healthcare: the RIGHT Statement

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    The quality of reporting of practice guidelines is often poor and there is no widely accepted guidance or standards for the reporting of practice guidelines in healthcare. An international working group (the RIGHT working group) was therefore established to address this gap. The group followed an existing framework for developing health research reporting guidelines and the EQUATOR (Enhancing the QUAlity and Transparency Of health Research) Network approach. We developed a checklist and an explanation and elaboration document. The RIGHT checklist includes 22 items that we consider essential for good reporting of practice guidelines. These items encompass basic information (items 1-4), background (items 5-9), evidence (items 10-12), recommendations (items 13-15), review and quality assurance (items 16-17), funding and declaration and management of interests (items 18-19), and other information (items 20-22). The RIGHT checklist can assist developers when reporting their guidelines, support journal editors and peer reviewers when considering guideline reports, and help healthcare practitioners understand and implement a guideline

    Morphological and phylogenetic analyzes reveal two new species of Melanconiella from Fujian Province, China

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    IntroductionSpecies of Melanconiella include a diverse array of plant pathogens as well as endophytic fungi. Members of this genus have been frequently collected from the family Betulaceae (birches) in Europe and North America. Little, however, if known concerning the distribution of Melanconiella and/or their potential as pathogens of other plant hosts.MethodsFungi were noted and isolated from diseased leaves of Loropetalum chinense (Chinese fringe flower) and Camellia sinensis (tea) in Fujian Province, China. Genomic DNA was extracted from fungal isolates and the nucleotide sequences of four loci were determined and sued to construct phylogenetic trees. Morphological characteristics of fungal structures were determined via microscopic analyses.ResultsFour strains and two new species of Melanconiella were isolated from infected leaves of L. chinense and C. sinensis in Fujian Province, China. Based on morphology and a multi-gene phylogeny of the internal transcribed spacer regions with the intervening 5.8S nrRNA gene (ITS), the 28S large subunit of nuclear ribosomal RNA (LSU), the second largest subunit of RNA polymerase II (RPB2), and the translation elongation factor 1-α gene (TEF1-α), Melanconiellaloropetali sp. nov. and Melanconiellacamelliae sp. nov. were identified and described herein. Detailed descriptions, illustrations, and a key to the known species of Melanconiella are provided.DiscussionThese data identify new species of Melanconiella, expanding the potential range and distribution of these dark septate fungi. The developed keys provide a reference source for further characterization of these fungi

    Parent-of-origin-specific allelic associations among 106 genomic loci for age at menarche.

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    Age at menarche is a marker of timing of puberty in females. It varies widely between individuals, is a heritable trait and is associated with risks for obesity, type 2 diabetes, cardiovascular disease, breast cancer and all-cause mortality. Studies of rare human disorders of puberty and animal models point to a complex hypothalamic-pituitary-hormonal regulation, but the mechanisms that determine pubertal timing and underlie its links to disease risk remain unclear. Here, using genome-wide and custom-genotyping arrays in up to 182,416 women of European descent from 57 studies, we found robust evidence (P < 5 × 10(-8)) for 123 signals at 106 genomic loci associated with age at menarche. Many loci were associated with other pubertal traits in both sexes, and there was substantial overlap with genes implicated in body mass index and various diseases, including rare disorders of puberty. Menarche signals were enriched in imprinted regions, with three loci (DLK1-WDR25, MKRN3-MAGEL2 and KCNK9) demonstrating parent-of-origin-specific associations concordant with known parental expression patterns. Pathway analyses implicated nuclear hormone receptors, particularly retinoic acid and γ-aminobutyric acid-B2 receptor signalling, among novel mechanisms that regulate pubertal timing in humans. Our findings suggest a genetic architecture involving at least hundreds of common variants in the coordinated timing of the pubertal transition
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