1,908 research outputs found

    EBF1-deficient bone marrow stroma elicits persistent changes in HSC potential

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    Crosstalk between mesenchymal stromal cells (MSCs) and hematopoietic stem cells (HSCs) is essential for hematopoietic homeostasis and lineage output. Here, we investigate how transcriptional changes in bone marrow (BM) MSCs result in long-lasting effects on HSCs. Single-cell analysis of Cxcl12-abundant reticular (CAR) cells and PDGFRα+Sca1+ (PαS) cells revealed an extensive cellular heterogeneity but uniform expression of the transcription factor gene Ebf1. Conditional deletion of Ebf1 in these MSCs altered their cellular composition, chromatin structure and gene expression profiles, including the reduced expression of adhesion-related genes. Functionally, the stromal-specific Ebf1 inactivation results in impaired adhesion of HSCs, leading to reduced quiescence and diminished myeloid output. Most notably, HSCs residing in the Ebf1-deficient niche underwent changes in their cellular composition and chromatin structure that persist in serial transplantations. Thus, genetic alterations in the BM niche lead to long-term functional changes of HSCs

    Action Sequencing Using Visual Permutations

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    Humans can easily reason about the sequence of high level actions needed to complete tasks, but it is particularly difficult to instil this ability in robots trained from relatively few examples. This work considers the task of neural action sequencing conditioned on a single reference visual state. This task is extremely challenging as it is not only subject to the significant combinatorial complexity that arises from large action sets, but also requires a model that can perform some form of symbol grounding, mapping high dimensional input data to actions, while reasoning about action relationships. This paper takes a permutation perspective and argues that action sequencing benefits from the ability to reason about both permutations and ordering concepts. Empirical analysis shows that neural models trained with latent permutations outperform standard neural architectures in constrained action sequencing tasks. Results also show that action sequencing using visual permutations is an effective mechanism to initialise and speed up traditional planning techniques and successfully scales to far greater action set sizes than models considered previously.Comment: This paper has been accepted for publication at IEEE RA-

    Coupled-barrier diffusion: the case of oxygen in silicon

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    Oxygen migration in silicon corresponds to an apparently simple jump between neighboring bridge sites. Yet, extensive theoretical calculations have so far produced conflicting results and have failed to provide a satisfactory account of the observed 2.52.5 eV activation energy. We report a comprehensive set of first-principles calculations that demonstrate that the seemingly simple oxygen jump is actually a complex process involving coupled barriers and can be properly described quantitatively in terms of an energy hypersurface with a ``saddle ridge'' and an activation energy of 2.5\sim 2.5 eV. Earlier calculations correspond to different points or lines on this hypersurface.Comment: 4 Figures available upon request. Accepted for publication in Phys. Rev. Let

    Detection of Multiple Human Papillomavirus Genotypes in Anal Carcinoma

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    Infection with human papillomavirus (HPV) is a major risk factor for development of anal squamous cell carcinoma. Despite over 100 genotypes of the virus, HPV 16 and 18 are considered pathogenic as they are seen in the majority of cervical and anal cancers. We have employed a custom microarray to examine DNA for several HPV genotypes. We aimed to determine the accuracy of our microarray in anal cancer DNA for HPV genotypes compared to the DNA sequencing gold standard

    AN OBSERVATIONAL STUDY TO VALIDATE THE SYMPTOMATOLOGY AND TO EVOLVE THE DIAGNOSTIC METHODOLOGY OF SIRAKKAMBA VATHAM THROUGH SIDDHA DIAGNOSTIC TOOLS

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    Sirakamba vatham is a clinical entity described by Sage Yugi in his treatise Yugi Vaithiya Chinthamani- 800, as one among the 80 types of Vatha diseases described in Siddha system of medicine. The study was aimed at in depth analysis of the clinical features mentioned under Sirakamba vatham of Siddha literature and to evolve standard Siddha diagnostic methods for management for Sirakamba vatham. This study was an observational, single center study with the sample size of 26, divided into Group I (control group) having normal individuals and group II (cases with Sirakkamba vatham). At the end of the study, it was concluded, that the symptoms of Sirakkamba vatham closely resembled the symptoms of Cerebro Vascular Accident especially of posterior circulation stroke

    VALIDATION OF SIDDHA PATHOLOGICAL CONCEPTS OF SIRAKAMBAVATHAM AND ITS PARALLEL ANALYSIS WITH CEREBRO VASCULAR ACCIDENTS (STROKE)

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    The Siddha system of medicine is widely practiced in South India and consists of an enormous classical literature that emphasize on pathological basis of disease. Contrary to conventional pathological basis of diseases, the Siddha pathology is solely based on the humoral makeup of individuals and rests on the conceptual framework formed by 96 Thathuvams (philosophies). These concepts connect the physical and inert energies of human body facilitating its existence at subtle and gross levels. Sirakkambavatham is one among the 80 Vatha diseases mentioned in the Siddha literature Yugivaithiyasinthaamani. The present literature survey has been conducted to provide an updated integrative framework of information about the pathological concepts of Sirakkambavatham from Siddha literature and its parallel analysis with Cerebrovascular accidents (Stroke).Validating the traditional text in the limelight of modern literature unveils the traditional wisdom of ancient saints of South India and provides a better approach for disease diagnosis, prevention and its management

    Seasonal landings of oil sardine, Sardinella longiceps at Rameswaram, Pamban and Mandapam areas

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    Unusual and unprecedented landings of oil sardine, Sardinella langiceps were noticed at Rameswaram and Pamban during January and February 1992. The estimated catch of oil sardine at Rameswaram for January- February 1992 was 4,561 t. The pair trawlers contributed 4,244 t and fish trawlers 317 t. The C/E varied from 1.5 to 8 t. At Pamban the pair trawling during the period realised 741 t
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