Fate maps and cell differentiation in the amphibian embryo – an experimental study

Development ◽  
1979 ◽  
Vol 54 (1) ◽  
pp. 113-130
Author(s):  
Ulf Landström ◽  
Søren Løvtrup
Keyword(s):  
Cell Differentiation ◽  
Striated Muscle ◽  
Heparan Sulphate ◽  
Fate Map ◽  
Amphibian Embryo ◽  
Undifferentiated Cells ◽  
Mesenchyme Cells ◽  
The One ◽  
Endodermal Cells ◽  
Insight Into

The aim of this paper is to test two different fate maps for the amphibian blastula with respect to their predictions concerning the process of cell differentiation. The first of these fate maps is the one proposed by Vogt, according to which all three germ layers can be projected on to the surface of the embryo. The second is a revision which claims that only endoderm and ectoderm are located in the surface, while the mesoderm is represented by free cells in the interior of the embryo. The testing has been performed by observing the differentiation of small explants of cells taken from various regions of the embryo. It was found that the spontaneous cell differentiation comprises three patterns: undifferentiated cells (free interior cells and circumpolar endodermal cells), fibroblast-like cells (the remaining endodermal cells) and epidermis (ectodermal cells). Further differentiation occurs only through induction, exerted either by the fibroblast-like endodermal cells or by heparan sulphate. When induced, the equatorial ectodermal cells give rise to swollen, hyaline cells (chordocytes), while the remaining ectodermal cells form a sequence of cell differentiation patterns, mesenchyme cells, nerve cells, melanophores and xanthophores. The free interior cells differentiate into striated muscle cells and elongated collagen-producing fibroblasts. Our results thus confirm the revised fate map, and they also give an insight into the mechanisms of the initial cell differentiations in the amphibian embryo.

Early embryonic expression ofFGF4/6/9gene and its role in the induction of mesenchyme and notochord inCiona savignyiembryos

Development ◽  
2002 ◽  
Vol 129 (7) ◽  
pp. 1729-1738 ◽  
Author(s):  
Kaoru S. Imai ◽  
Nori Satoh ◽  
Yutaka Satou
Keyword(s):  
Cell Differentiation ◽  
Nuclear Localization ◽  
Target Genes ◽  
Muscle Cells ◽  
Cell Stage ◽  
Ciona Savignyi ◽  
Mesenchyme Cell ◽  
Notochord Cells ◽  
Mesenchyme Cells ◽  
Endodermal Cells

In early Ciona savignyi embryos, nuclear localization of β-catenin is the first step of endodermal cell specification, and triggers the activation of various target genes. A cDNA for Cs-FGF4/6/9, a gene activated downstream of β-catenin signaling, was isolated and shown to encode an FGF protein with features of both FGF4/6 and FGF9/20. The early embryonic expression of Cs-FGF4/6/9 was transient and the transcript was seen in endodermal cells at the 16- and 32-cell stages, in notochord and muscle cells at the 64-cell stage, and in nerve cord and muscle cells at the 110-cell stage; the gene was then expressed again in cells of the nervous system after neurulation. When the gene function was suppressed with a specific antisense morpholino oligo, the differentiation of mesenchyme cells was completely blocked, and the fate of presumptive mesenchyme cells appeared to change into that of muscle cells. The inhibition of mesenchyme differentiation was abrogated by coinjection of the morpholino oligo and synthetic Cs-FGF4/6/9 mRNA. Downregulation of β-catenin nuclear localization resulted in the absence of mesenchyme cell differentiation due to failure of the formation of signal-producing endodermal cells. Injection of synthetic Cs-FGF4/6/9 mRNA in β-catenin-downregulated embryos evoked mesenchyme cell differentiation. These results strongly suggest that Cs-FGF4/6/9 produced by endodermal cells acts an inductive signal for the differentiation of mesenchyme cells. On the other hand, the role of Cs-FGF4/6/9 in the induction of notochord cells is partial; the initial process of the induction was inhibited by Cs-FGF4/6/9 morpholino oligo, but notochord-specific genes were expressed later to form a partial notochord.

When Romania met the Cohesion Policy. Regional governance in-between national conventions and European ideals

2018 ◽  
Vol 18 (2) ◽  
pp. 127-148 ◽  
Author(s):  
Alexandru Brad
Keyword(s):  
Regional Policy ◽  
Development Planning ◽  
Regional Governance ◽  
Theoretical Ground ◽  
Cohesion Policy ◽  
Redistributive Policy ◽  
Policy Context ◽  
Core Areas ◽  
The One ◽  
Insight Into

This article is about the practice of territorial governance emerging at the junction of European Union-sanctioned ideals and Romanian development-planning traditions. On the one hand, the European agenda emphasises a smart, inclusive, sustainable model of economic growth. However, the persisting centralised workings of the Romanian state significantly alters the scope of regional interventions. As such, while core cities grew their economies swiftly, peripheral places were left in an unrelenting stagnation. My first aim is to provide a theoretical ground for a practicecentred approach to understanding territorial governance. Second, by drawing on Romania’s regional policy context as an example, I give an insight into how practices of partnership and competition fare in a context of ongoing territorial polarisation. I conclude by emphasising the need for a regional redistributive policy mechanism, one which should enable and assist non-core areas to access capacities for defining and implementing development projects.

Marx, Silk Poems, and the Pretext of Qualities

2020 ◽  
Vol 151 (1) ◽  
pp. 96-126
Author(s):  
Kathryn Crim
Keyword(s):  
The Other ◽  
Use Value ◽  
Working Day ◽  
The One ◽  
Insight Into

Karl Marx’s comments on silk manufacture in “The Working Day” chapter of Capital, volume 1, demonstrate how “quality”—usually associated with “use value”—has been mobilized by capital to naturalize industrialized labor. Putting his insight into conversation with a recent multimedia poetic project, Jen Bervin’s Silk Poems (2016–17), this essay examines the homology between, on the one hand, poetry’s avowed task of fitting form to content and, on the other, the ideology of labor that fits specific bodies to certain materials and tasks.

Relational Chase Procedures Interpreted as Resolution with Paramodulation1

1991 ◽  
Vol 15 (2) ◽  
pp. 123-138
Author(s):  
Joachim Biskup ◽  
Bernhard Convent
Keyword(s):  
Alternative Interpretation ◽  
Order Logic ◽  
First Order Logic ◽  
Inference Problem ◽  
First Order ◽  
Inference Problems ◽  
The One ◽  
The Relationship ◽  
Theoretical Foundations ◽  
Insight Into

In this paper the relationship between dependency theory and first-order logic is explored in order to show how relational chase procedures (i.e., algorithms to decide inference problems for dependencies) can be interpreted as clever implementations of well known refutation procedures of first-order logic with resolution and paramodulation. On the one hand this alternative interpretation provides a deeper insight into the theoretical foundations of chase procedures, whereas on the other hand it makes available an already well established theory with a great amount of known results and techniques to be used for further investigations of the inference problem for dependencies. Our presentation is a detailed and careful elaboration of an idea formerly outlined by Grant and Jacobs which up to now seems to be disregarded by the database community although it definitely deserves more attention.

Recent progress in the freeze-etching technique

1971 ◽  
Vol 261 (837) ◽  
pp. 121-131 ◽  
Keyword(s):  
High Vacuum ◽  
Molecular Size ◽  
Etching Technique ◽  
Structural Distortions ◽  
Shadow Casting ◽  
Structural Details ◽  
Freeze Etching ◽  
The One ◽  
Insight Into ◽  
Made In

The freeze-etching technique must be improved if structures at the molecular size level are to be seen. The limitations of the technique are discussed here together with the progress made in alleviating them. The vitrification of living specimens is limited by the fact that very high freezing rates are needed. The critical freezing rate can be lowered on the one hand by the introduction of antifreeze agents, on the other hand by the application of high hydrostatic pressure. The fracture process may cause structural distortions in the fracture face of the frozen specimen. The ‘double-replica’ method allows one to evaluate such artefacts and provides an insight into the way that membranes split. During etching there exists the danger of contaminating the fracture faces with condensable gases. Because of specimen temperatures below —110 °C, special care has to be taken in eliminating water vapour from the high vacuum. An improvement in coating freeze-etched specimens has resulted from the application of electron guns for evaporation of the highest melting-point metals. If heat transfer from gun to specimen is reduced to a minimum, Pt, Ir, Ta, W and C can be used for shadow casting. Best results are obtained with Pt-C and Ta-W . With the help of decoration effects Pt-C shadow castings give the most information about the fine structural details of the specimen.

Evaluation of changes in mechanical properties of O-ring in one-piece and two-piece ball retained implant-supported overdentures: A three-year retrospective study.

2021 ◽  
Author(s):  
Fathima Banu Raza ◽  
Anand Kumar
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Retrospective Study ◽  
Statistical Analysis ◽  
Wear Rate ◽  
Digital Camera ◽  
Maximum Displacement ◽  
Pin On Disc ◽  
The One ◽  
Insight Into

The o-rings in ball retained overdentures deteriorate with time and need replacement to restore the retentive quality. We evaluated retrospectively the mechanical properties of o-rings after 3 years in function in one and two-piece implant-supported overdentures. The o-rings were retrieved from one-piece (Myriad snap, Equinox-Straumann, 3.3 x 13mm) and two-piece (Neo Biotech, 3.3 x 13mm) implant-supported overdenture patients. A total of 16 pairs of matrices were tested for wear, type of damage and elasticity using Pin on Disc method, USB Digital Camera in 30x zoom and Universal Tensile Machine respectively. The statistical analysis for independent groups were done with the Mann-Whitney U test. Assessment of used O-rings showed 84% more wear in the two-piece system with an abrasive type of damage while 46% wear in the one-piece system with a compressive type of damage. The o-rings in one-piece system showed increase in elongation and maximum displacement to 2% and 7% respectively, while two-piece system showed decrease in elongation and maximum displacement by 13% and 6% respectively. In one-piece system, the loss of retention was more with slow wear rate and in two-piece system, the wear resistance of O-rings decreased due to increased stiffness. Further studies to evaluate the changes in O-ring with increased sample size and at interval 1 year will pave way for insight into the progressive changes in the mechanical properties of an O-ring.

Hegel’s Account of Christianity and Religious Alienation

2021 ◽  
Vol 13 (1) ◽  
pp. 129-152
Author(s):  
Jon Stewart
Keyword(s):  
Philosophy Of Religion ◽  
The Other ◽  
The World ◽  
The One ◽  
Insight Into

In his Lectures on the Philosophy of Religion, Hegel argues that the development of the religions of the world leads up to and culminates in Christianity, which is the one true religion. One key element which separates Christianity from the other religions, according to Hegel, concerns the issue of alienation. He argues that the previous religions all contain some form of alienation, which can be found in their conceptions of the divine. In this paper, I wish to examine Hegel’s view that Christianity alone overcomes religious alienation. What is it that makes Christianity so special in this regard? This is a particularly important issue given that the question of alienation is so central in the post-Hegelian thinkers such as Feuerbach, Bauer, and Marx, who all insist that, far from overcoming alienation, Christianity is guilty of causing it. I wish to argue that this issue provides new insight into the old criticism of Hegel as a thinker of abstraction.

scholarly journals Applying Corpus Data to Define Needs in Web Localization Training

2012 ◽  
Vol 56 (4) ◽  
pp. 998-1021 ◽  
Author(s):  
Miguel ángel Jiménez-Crespo ◽  
Maribel Tercedor
Keyword(s):  
Empirical Research ◽  
Training Programs ◽  
The Other ◽  
Contrastive Study ◽  
Learner Corpus ◽  
Text Types ◽  
Corpus Data ◽  
University Level ◽  
The One ◽  
Insight Into

Localization is increasingly making its way into translation training programs at university level. However, there is still a scarce amount of empirical research addressing issues such as defining localization in relation to translation, what localization competence entails or how to best incorporate intercultural differences between digital genres, text types and conventions, among other aspects. In this paper, we propose a foundation for the study of localization competence based upon previous research on translation competence. This project was developed following an empirical corpus-based contrastive study of student translations (learner corpus), combined with data from a comparable corpus made up of an original Spanish corpus and a Spanish localized corpus. The objective of the study is to identify differences in production between digital texts localized by students and professionals on the one hand, and original texts on the other. This contrastive study allows us to gain insight into how localization competence interrelates with the superordinate concept of translation competence, thus shedding light on which aspects need to be addressed during localization training in university translation programs.

Would You Like Some World Music with your Latte? Starbucks, Putumayo, and Distributed Tourism

2004 ◽  
Vol 1 (2) ◽  
pp. 209-223 ◽  
Author(s):  
ANAHID KASSABIAN
Keyword(s):  
Quantum Mechanics ◽  
Public Spaces ◽  
World Music ◽  
The Other ◽  
Retail Stores ◽  
Theoretical Perspectives ◽  
The One ◽  
Coffee Shops ◽  
Insight Into

Through an examination of the labels Hear Music and Putumayo and their place in coffee shops and retail stores on the one hand, and of world music scholarship on the other, I argue that listening to world music in public spaces demands new theoretical perspectives. The kinds of tourism that take place in listening to world music inattentively suggest a kind of bi-location. Borrowing from quantum mechanics, I suggest that the term ‘entanglement’ might offer some insight into this bi-location and the ‘distributed tourism’ that I argue is taking place.

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