41 research outputs found

    Semi-supervised segmentation of ultrasound images based on patch representation and continuous min cut.

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    Ultrasound segmentation is a challenging problem due to the inherent speckle and some artifacts like shadows, attenuation and signal dropout. Existing methods need to include strong priors like shape priors or analytical intensity models to succeed in the segmentation. However, such priors tend to limit these methods to a specific target or imaging settings, and they are not always applicable to pathological cases. This work introduces a semi-supervised segmentation framework for ultrasound imaging that alleviates the limitation of fully automatic segmentation, that is, it is applicable to any kind of target and imaging settings. Our methodology uses a graph of image patches to represent the ultrasound image and user-assisted initialization with labels, which acts as soft priors. The segmentation problem is formulated as a continuous minimum cut problem and solved with an efficient optimization algorithm. We validate our segmentation framework on clinical ultrasound imaging (prostate, fetus, and tumors of the liver and eye). We obtain high similarity agreement with the ground truth provided by medical expert delineations in all applications (94% DICE values in average) and the proposed algorithm performs favorably with the literature

    Desmoglein 3, via an Interaction with E-cadherin, Is Associated with Activation of Src

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    Desmoglein 3 (Dsg3), a desmosomal adhesion protein, is expressed in basal and immediate suprabasal layers of skin and across the entire stratified squamous epithelium of oral mucosa. However, increasing evidence suggests that the role of Dsg3 may involve more than just cell-cell adhesion.To determine possible additional roles of Dsg3 during epithelial cell adhesion we used overexpression of full-length human Dsg3 cDNA, and RNAi-mediated knockdown of this molecule in various epithelial cell types. Overexpression of Dsg3 resulted in a reduced level of E-cadherin but a colocalisation with the E-cadherin-catenin complex of the adherens junctions. Concomitantly these transfected cells exhibited marked migratory capacity and the formation of filopodial protrusions. These latter events are consistent with Src activation and, indeed, Src-specific inhibition reversed these phenotypes. Moreover Dsg3 knockdown, which also reversed the decreased level of E-cadherin, partially blocked Src phosphorylation.Our data are consistent with the possibility that Dsg3, as an up-stream regulator of Src activity, helps regulate adherens junction formation

    Cancer Biomarker Discovery: The Entropic Hallmark

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    Background: It is a commonly accepted belief that cancer cells modify their transcriptional state during the progression of the disease. We propose that the progression of cancer cells towards malignant phenotypes can be efficiently tracked using high-throughput technologies that follow the gradual changes observed in the gene expression profiles by employing Shannon's mathematical theory of communication. Methods based on Information Theory can then quantify the divergence of cancer cells' transcriptional profiles from those of normally appearing cells of the originating tissues. The relevance of the proposed methods can be evaluated using microarray datasets available in the public domain but the method is in principle applicable to other high-throughput methods. Methodology/Principal Findings: Using melanoma and prostate cancer datasets we illustrate how it is possible to employ Shannon Entropy and the Jensen-Shannon divergence to trace the transcriptional changes progression of the disease. We establish how the variations of these two measures correlate with established biomarkers of cancer progression. The Information Theory measures allow us to identify novel biomarkers for both progressive and relatively more sudden transcriptional changes leading to malignant phenotypes. At the same time, the methodology was able to validate a large number of genes and processes that seem to be implicated in the progression of melanoma and prostate cancer. Conclusions/Significance: We thus present a quantitative guiding rule, a new unifying hallmark of cancer: the cancer cell's transcriptome changes lead to measurable observed transitions of Normalized Shannon Entropy values (as measured by high-throughput technologies). At the same time, tumor cells increment their divergence from the normal tissue profile increasing their disorder via creation of states that we might not directly measure. This unifying hallmark allows, via the the Jensen-Shannon divergence, to identify the arrow of time of the processes from the gene expression profiles, and helps to map the phenotypical and molecular hallmarks of specific cancer subtypes. The deep mathematical basis of the approach allows us to suggest that this principle is, hopefully, of general applicability for other diseases

    EVIDENCE FROM A FORTUNE 500 FIRM By

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    With telecommuting becoming so popular and the technology that enables it becoming more advanced, is geography still important to innovation of the firm? Geography, along with satisfaction and telecommuting as a lifestyle choice, will be examined in this study. Telecommuters often report both positive and negative effects of telecommuting. When the two are weighed together, are telecommuters more satisfied than dissatisfied? Primary data from a survey administered to 500 telecommuters and 500 traditional employees of a Fortune 500 firm are used to answer these questions. With construct validity, using cross tabulation with a chi-square value as an indicator, this study finds that telecommuters are satisfied despite negative effects of telecommuting and having physical ties to the office is not dependent on satisfaction. It is also determined through executive interviews and chi-square values of certain constructs that telecommuting is indeed a lifestyle choice. Although geography is still deemed important, this will likely change in the future as more people entering the workplace are accustomed to less face-to-face interaction. TELECOMMUTING SATISFACTION, LIFESTYLE CHOICE AND GEOGRAPHY

    A sequence downstream of AAUAAA is required for rabbit beta-globin mRNA 3'-end formation.

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    The sequence AAUAAA, found 11-30 base pairs (bp) upstream of the poly(A) site of most non-histone eukaryotic messenger RNAs (mRNAs) forms an essential part of the recognition site for 3'-end processing of the primary transcript. However, the sequence AATAAA is found in transcribed regions of genes and is differentially utilized in genes containing multiple copies of the sequence within the 3'-noncoding region, suggesting that the hexanucleotide alone does not comprise a complete recognition site. Therefore, it seems likely that additional sequences are required to form a complete recognition site for 3'-end formation. We have investigated the sequence requirements for mRNA 3'-end formation using the rabbit beta-globin gene as a model system. Here we demonstrate that an additional sequence 3' to AAUAAA is required for the correct 3'-end formation of rabbit beta-globin mRNA
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