18,733 research outputs found

    Tissue absence initiates regeneration through Follistatin-mediated inhibition of Activin signaling

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    Regeneration is widespread, but mechanisms that activate regeneration remain mysterious. Planarians are capable of whole-body regeneration and mount distinct molecular responses to wounds that result in tissue absence and those that do not. A major question is how these distinct responses are activated. We describe a follistatin homolog (Smed-follistatin) required for planarian regeneration. Smed-follistatin inhibition blocks responses to tissue absence but does not prevent normal tissue turnover. Two activin homologs (Smed-activin-1 and Smed-activin-2) are required for the Smed-follistatin phenotype. Finally, Smed-follistatin is wound-induced and expressed at higher levels following injuries that cause tissue absence. These data suggest that Smed-follistatin inhibits Smed-Activin proteins to trigger regeneration specifically following injuries involving tissue absence and identify a mechanism critical for regeneration initiation, a process important across the animal kingdom.National Institutes of Health (U.S.) (NIH (R01GM080639))W. M. Keck FoundationHoward Hughes Medical Institute (Early career scientist

    Tissue absence initiates regeneration through Follistatin-mediated inhibition of Activin signaling

    Get PDF
    Regeneration is widespread, but mechanisms that activate regeneration remain mysterious. Planarians are capable of whole-body regeneration and mount distinct molecular responses to wounds that result in tissue absence and those that do not. A major question is how these distinct responses are activated. We describe a follistatin homolog (Smed-follistatin) required for planarian regeneration. Smed-follistatin inhibition blocks responses to tissue absence but does not prevent normal tissue turnover. Two activin homologs (Smed-activin-1 and Smed-activin-2) are required for the Smed-follistatin phenotype. Finally, Smed-follistatin is wound-induced and expressed at higher levels following injuries that cause tissue absence. These data suggest that Smed-follistatin inhibits Smed-Activin proteins to trigger regeneration specifically following injuries involving tissue absence and identify a mechanism critical for regeneration initiation, a process important across the animal kingdom.National Institutes of Health (U.S.) (NIH (R01GM080639))W. M. Keck FoundationHoward Hughes Medical Institute (Early career scientist

    Usulan Perbaikan Operation Point Sheet Pada Mesin Feeder Aida 1100 PT. Xxx Dengan Menggunakan Metode Smed

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    Single Minute Exchange of Die (SMED) merupakan salah satu alat lean yang penting untuk mengurangi waste dan meningkatkan fleksibilitas dalam proses manufaktur yang memungkinkan dalam pengurangan ukuran lot dan perbaikan aliran manufaktur. SMED mengurangi waktu non-produktif dengan mempersatukan dan standardisasi operasi dalam pergantian alat, dengan menggunakan teknik sederhana dan aplikasi yang mudah. Namun proses tersebut tidak dapat memberikan hasil yang spesifik dalam pelaksanaannya, dimana masih dapat dilakukan suatu perbaikan. Untuk mengatasi hal ini, data statistik dan alat-alat teknik industri dapat diintegrasikan dalam pendekatan SMED untuk meningkatkan hasil penerapan SMED. Penerapan pendekatan SMED yang diusulkan diuji untuk mesin feeder didalam industri otomotif PT. XXX. Implementasi ini memungkinkan adanya pengurangan waktu setup, melalui reorganisasi sumber daya internal Perusahaan tanpa membutuhkan investasi yang signifikan. Kata kunci: Lean manufacturing systems, Single Minute Exchange of Die, Quick ChangeOver. Single Minute Exchange of Die (SMED) is one of the essential lean tools to reduce waste and increase flexibility in manufacturing processes that enable the reduction of lot size and improving manufacturing flow. SMED reduces non-productive time by streamlining and standardizing operations in the turn of the tool, using simple techniques and easy application. But the process can not provide a specific result in the implementation, which can still be an improvement. To overcome this, statistical data and tools can be integrated in industrial engineering approaches to improve outcomes SMED SMED implementation. The proposed application of SMED approach was tested for the automotive industry in the feeder machine PT. XXX. This implementation allows for the reduction of setup time, through the reorganization of the company's internal resources without requiring significant investment

    Stem cells and fluid flow drive cyst formation in an invertebrate excretory organ.

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    Cystic kidney diseases (CKDs) affect millions of people worldwide. The defining pathological features are fluid-filled cysts developing from nephric tubules due to defective flow sensing, cell proliferation and differentiation. The underlying molecular mechanisms, however, remain poorly understood, and the derived excretory systems of established invertebrate models (Caenorhabditis elegans and Drosophila melanogaster) are unsuitable to model CKDs. Systematic structure/function comparisons revealed that the combination of ultrafiltration and flow-associated filtrate modification that is central to CKD etiology is remarkably conserved between the planarian excretory system and the vertebrate nephron. Consistently, both RNA-mediated genetic interference (RNAi) of planarian orthologues of human CKD genes and inhibition of tubule flow led to tubular cystogenesis that share many features with vertebrate CKDs, suggesting deep mechanistic conservation. Our results demonstrate a common evolutionary origin of animal excretory systems and establish planarians as a novel and experimentally accessible invertebrate model for the study of human kidney pathologies

    Food Safety Information and Food Demand Effects of Temporary and Permanent News

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    This paper examines the cross-impacts of food safety news concerning one product on the demand for another product, using the Danish demand for pasteurized eggs versus shell eggs as an illustrative case. The study identifies news with a temporary impact and news with a permanent impact on consumers' food demand behavior. The techniques used to identify the permanent versus temporary news are recursive estimation and parameter stability. Whereas "permanent" news is identified to be represented by a specific individual event, "temporary" news concerning salmonella in eggs is aggregated into a news-index variable. Both temporary and permanent news concerning salmonella in shell eggs appear to have significant positive impacts on the demand for pasteurized eggs. The model is estimated as an Error Correction Model. Consumers are found to adjust quite rapidly to both temporary and permanent news. Both the composition of egg consumption accounted as mean budget shares varies across socio-demographic household groups as well as the impact of the considered permanent news.salmonella, news, egg demand, error correction model, socio-economic groups, Food Consumption/Nutrition/Food Safety,

    Towards an understanding of the means-ends relationship in citizenship education

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    While it is clear that all educational undertakings consist of ends and means, the relationship between the two is far from straightforward. This article proposes a framework for understanding the relationship in the context of citizenship education. Qualitative research was undertaken of three educational initiatives in Brazil: the schools of the Landless Movement, the Plural School framework in the city of Belo Horizonte, and the Voter of the Future programme, run by the Electoral Tribunals. Case studies were carried out of each, involving documentary analysis, interviews and observations. Analysis of the relationship between ends and means in each case gave rise to two key frames: the first, ‘proximity’, refers to the extent to which ends and means are separate or unified; the second, ‘rationale’, refers to the grounds on which means are chosen. Finally, the implications of this framework for understanding curriculum are drawn out

    Variation Modeling of Lean Manufacturing Performance Using Fuzzy Logic Based Quantitative Lean Index

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    The lean index is the sum of weighted scores of performance variables that describe the lean manufacturing characteristics of a system. Various quantitative lean index models have been advanced for assessing lean manufacturing performance. These models are represented by deterministic variables and do not consider variation in manufacturing systems. In this article variation is modeled in a quantitative fuzzy logic based lean index and compared with traditional deterministic modeling. By simulating the lean index model for a manufacturing case it is found that the latter tend to under or overestimate performance and the former provides a more robust lean assessment

    Conservation of epigenetic regulation by the MLL3/4 tumour suppressor in planarian pluripotent stem cells

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    Currently, little is known about the evolution of epigenetic regulation in animal stem cells. Here we demonstrate, using the planarian stem cell system to investigate the role of the COMPASS family of MLL3/4 histone methyltransferases that their function as tumor suppressors in mammalian stem cells is conserved over a long evolutionary distance. To investigate the potential conservation of a genome-wide epigenetic regulatory program in animal stem cells, we assess the effects of Mll3/4 loss of function by performing RNA-seq and ChIP-seq on the G2/M planarian stem cell population, part of which contributes to the formation of outgrowths. We find many oncogenes and tumor suppressors among the affected genes that are likely candidates for mediating MLL3/4 tumor suppression function. Our work demonstrates conservation of an important epigenetic regulatory program in animals and highlights the utility of the planarian model system for studying epigenetic regulation
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