2,391 research outputs found

    Epigenetic reprogramming of the zygote in mice and men: on your marks, get set, go!

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    Gametogenesis (spermatogenesis and oogenesis) is accompanied by the acquisition of gender-specific epigenetic marks, such as DNA methylation, histone modifications and regulation by small RNAs, to form highly differentiated, but transcriptionally silent cell-types in preparation for fertilisation. Upon fertilisation, extensive global epigenetic reprogramming takes place to remove the previously acquired epigenetic marks and produce totipotent zygotic states. It is the aim of this review to delineate the cellular and molecular events involved in maternal, paternal and zygotic epigenetic reprogramming from the time of gametogenesis, through fertilisation, to the initiation of zygotic genome activation for preimplantation embryonic development. Recent studies have begun to uncover the indispensable functions of epigenetic players during gametogenesis, fertilisation and preimplantation embryo development, and a more comprehensive understanding of these early events will be informative for increasing pregnancy success rates, adding particular value to assisted fertility programmes

    Simulation of Meshes in a Faulty Supercube with Unbounded Expansion

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    [[abstract]]Reconfiguring meshes in a faulty Supercube is investigated in the paper. The result can readily be used in the optimal embedding of a mesh (or a torus) of processors in a faulty Supercube with unbounded expansion. There are embedding algorithms proposed in this paper. These embedding algorithms show a mesh with any number of nodes can be embedded into a faulty Supercube with load 1, congestion 1, and dilation 3 such that O(n2-w2) faults can be tolerated, where n is the dimension of the Supercube and 2w is the number of nodes of the mesh. The meshes and hypercubes are widely used interconnection architectures in parallel computing, grid computing, sensor network, and cloud computing. In addition, the Supercubes are superior to hypercube in terms of embedding a mesh and torus under faults. Therefore, we can easily port the parallel or distributed algorithms developed for these structuring of mesh and torus to the Supercube.[[notice]]補正完畢[[journaltype]]國外[[incitationindex]]EI[[ispeerreviewed]]Y[[booktype]]紙本[[countrycodes]]KO

    An Incomplete Cholesky Factorization for Dense Symmetric Positive Definite Matrices

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    In this paper, we study the use of an incomplete Cholesky factorization (ICF) as a preconditioner for solving dense symmetric positive definite linear systems. This method is suitable for situations where matrices cannot be explicitly stored but each column can be easily computed. Analysis and implementation of this preconditioner are discussed. We test the proposed ICF on randomly generated systems and large matrices from two practical applications: semidefinite programming and support vector machines. Numerical comparison with the diagonal preconditioner is also presented.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47957/1/10543_2004_Article_331278.pd

    Laparoscopic management of a giant adrenal cyst

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    AbstractAdrenal cysts, a rare entity, are usually nonfunctional and asymptomatic. Here, we report a 32-year-old woman who presented with mild breathlessness and vague abdominal fullness and discomfort that had lasted 6 months. Chest radiography showed elevation of the left side of the diaphragm. Abdominal sonography showed an anechoic lesion of >15cm, without a septum, that was situated over the left abdominal area. Abdominal computed tomography (CT) showed a 20cm suprarenal cyst located between the pancreas, spleen, and left kidney, causing anterior displacement of the pancreas and inferior displacement of the left kidney. Magnetic resonance imaging confirmed the CT and sonographic findings, and revealed that the cystic mass was originating from the left adrenal gland. Fluid analysis of the cystic lesion showed no evidence of infection or malignancy. A laparoscopic adrenalectomy was performed. Histopathologically, the adrenal tissue showed no evidence of adenoma or malignancy, and the cystic component showed a flattened endothelial lining with fibrotic tissue, consistent with an endothelial cyst. The postoperative course was uneventful and the patient had no evidence of recurrence during a 6-year follow-up. We discuss the diagnosis and management of adrenal cysts

    The collaboration of noise reduction and human vision system models for a visible watermarking algorithm

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    ABSTRACT A novel visible watermarking algorithm based on noise reduction and Human Visible System (HVS) model approach is presented in this study. In order to get the best tradeoff between the embedding energy of watermark and the perceptual translucence for visible watermark, the composite coefficients using global and local characteristics of the host image in the discrete wavelet transform (DWT) domain is considered. The application of the perceptual model of contrast-sensitive function (CSF) with the noise reduction of the visibility thresholds for HVS in DWT domain achieves the goal of fine tuning of the perceptual weights according to the basis function amplitudes for the best quality of perceptual translucence. Instead of three types of block classification-textures, edges and smooth areas, the computation of Noise Visibility Function (NVF) characterizes the local image properties to determine the optimal watermark locations and strength at the watermark embedding stage. The experimental results demonstrate that the proposed technique improves the PSNR values and visual quality than the CSF only based algorithms

    Use of an open-source CAD software program and additive manufacturing technology to design and fabricate a definitive cast for retrofitting a crown to an existing removable partial denture

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    This technical report describes a digital process for designing and fabricating a stackable definitive cast and die system to facilitate the fabrication of a new surveyed crown to retrofit to a removable partial denture (RPD). By using an open-source computer-aided design (CAD) software program, this technique provides an economical option for dental clinicians and laboratory technicians to use intraoral scans and design a stackable definitive cast and die system with minimal financial investment in the CAD software. In addition, this technique provides the advantage of a conventional indirect technique in that it can create a definitive cast with an RPD clasp assembly ready for the dental technician to properly contour the new surveyed crown, but without the need for the patient to be without the RPD during the process
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