5,832 research outputs found

    Integrated circuit flat-pack lead bender

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    Tool bends leads quickly and accurately for mounting on printed circuit boards. It has grooves and bend-angles aligned for particular circuit board applications

    Towards experimental therapies for retinal degenerative diseases

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    This thesis describes part of the preclinical road that is essential in developing experimental therapies for retinal degenerative diseases such as age-related macular degeneration (AMD) and a specific type of retinitis pigmentosa (RPE-RP). The retinal pigment epithelium (RPE) plays a significant role in the pathology of both diseases. Indeed, patients of all ages can be affected by conditions involving (primarily) the RPE. This thesis is focused on RPE disease pathology, illustrated by the complex retinal disease AMD and a specific genetic form of the monogenic disorder RP. Many experimental therapeutic strategies are being developed to treat AMD and RPE-RP; however, gene therapy and cell-replacement therapy can be considered important strategies for these diseases, especially because of the curative nature of these two treatment modalities. In this thesis, we first used a systematic approach to identify and analyze all preclinical studies that have been published regarding RPE cell-replacement strategy to treat retinal degenerative diseases (Chapter 2). We next used a genome-editing technique to create a new animal model for an RPE-RP subtype and characterized the model in-depth (Chapter 3). Additionally, we describe an induced preclinical model for AMD and its in-depth characterization (Chapter 4). As a final step, we describe the generation of a 3D-bio-printed tissue recapitulating the RPE and underlying tissues and its transplantation and integration into rat eyes (Chapter 5)

    Pre-processing for Triangulation of Probabilistic Networks

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    The currently most efficient algorithm for inference with a probabilistic network builds upon a triangulation of a network's graph. In this paper, we show that pre-processing can help in finding good triangulations forprobabilistic networks, that is, triangulations with a minimal maximum clique size. We provide a set of rules for stepwise reducing a graph, without losing optimality. This reduction allows us to solve the triangulation problem on a smaller graph. From the smaller graph's triangulation, a triangulation of the original graph is obtained by reversing the reduction steps. Our experimental results show that the graphs of some well-known real-life probabilistic networks can be triangulated optimally just by preprocessing; for other networks, huge reductions in their graph's size are obtained.Comment: Appears in Proceedings of the Seventeenth Conference on Uncertainty in Artificial Intelligence (UAI2001

    Nanomechanical optical devices fabricated with aligned wafer bonding

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    This paper reports on a new method for making some types of integrated optical nanomechanical devices. Intensity modulators as well as phase modulators were fabricated using several silicon micromachining techniques, including chemical mechanical polishing and aligned wafer bonding. This new method enables batch fabrication of the nanomechanical optical devices, and enhances their performance

    Confined coherence and analytic properties of Green's functions

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    A simple model of noninteracting electrons with a separable one-body potential is used to discuss the possible pole structure of single particle Green's functions for fermions on unphysical sheets in the complex frequency plane as a function of the system parameters. The poles in the exact Green's function can cross the imaginary axis, in contrast to recent claims that such a behaviour is unphysical. As the Green's function of the model has the same functional form as an approximate Green's function of coupled Luttinger liquids no definite conclusions concerning the concept of "confined coherence" can be drawn from the locations of the poles of this Green's function.Comment: 3 pages, 3 figure

    A Backtracking-Based Algorithm for Computing Hypertree-Decompositions

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    Hypertree decompositions of hypergraphs are a generalization of tree decompositions of graphs. The corresponding hypertree-width is a measure for the cyclicity and therefore tractability of the encoded computation problem. Many NP-hard decision and computation problems are known to be tractable on instances whose structure corresponds to hypergraphs of bounded hypertree-width. Intuitively, the smaller the hypertree-width, the faster the computation problem can be solved. In this paper, we present the new backtracking-based algorithm det-k-decomp for computing hypertree decompositions of small width. Our benchmark evaluations have shown that det-k-decomp significantly outperforms opt-k-decomp, the only exact hypertree decomposition algorithm so far. Even compared to the best heuristic algorithm, we obtained competitive results as long as the hypergraphs are not too large.Comment: 19 pages, 6 figures, 3 table

    Electronic coupling between Bi nanolines and the Si(001) substrate: An experimental and theoretical study

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    Atomic nanolines are one dimensional systems realized by assembling many atoms on a substrate into long arrays. The electronic properties of the nanolines depend on those of the substrate. Here, we demonstrate that to fully understand the electronic properties of Bi nanolines on clean Si(001) several different contributions must be accounted for. Scanning tunneling microscopy reveals a variety of different patterns along the nanolines as the imaging bias is varied. We observe an electronic phase shift of the Bi dimers, associated with imaging atomic p-orbitals, and an electronic coupling between the Bi nanoline and neighbouring Si dimers, which influences the appearance of both. Understanding the interplay between the Bi nanolines and Si substrate could open a novel route to modifying the electronic properties of the nanolines.Comment: 6 pages (main), 2 pages (SI), accepted by Phys. Rev.
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