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Sample records for paraxial mesoderm development

  1. The chick somitogenesis oscillator is arrested before all paraxial mesoderm is segmented into somites

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    McGrew Michael J

    2010-02-01

    Full Text Available Abstract Background Somitogenesis is the earliest sign of segmentation in the developing vertebrate embryo. This process starts very early, soon after gastrulation has initiated and proceeds in an anterior-to-posterior direction during body axis elongation. It is widely accepted that somitogenesis is controlled by a molecular oscillator with the same periodicity as somite formation. This periodic mechanism is repeated a specific number of times until the embryo acquires a defined specie-specific final number of somites at the end of the process of axis elongation. This final number of somites varies widely between vertebrate species. How termination of the process of somitogenesis is determined is still unknown. Results Here we show that during development there is an imbalance between the speed of somite formation and growth of the presomitic mesoderm (PSM/tail bud. This decrease in the PSM size of the chick embryo is not due to an acceleration of the speed of somite formation because it remains constant until the last stages of somitogenesis, when it slows down. When the chick embryo reaches its final number of somites at stage HH 24-25 there is still some remaining unsegmented PSM in which expression of components of the somitogenesis oscillator is no longer dynamic. Finally, we identify a change in expression of retinoic acid regulating factors in the tail bud at late stages of somitogenesis, such that in the chick embryo there is a pronounced onset of Raldh2 expression while in the mouse embryo the expression of the RA inhibitor Cyp26A1 is downregulated. Conclusions Our results show that the chick somitogenesis oscillator is arrested before all paraxial mesoderm is segmented into somites. In addition, endogenous retinoic acid is probably also involved in the termination of the process of segmentation, and in tail growth in general.

  2. Development of head and trunk mesoderm in the dogfish, Scyliorhinus torazame: I. Embryology and morphology of the head cavities and related structures.

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    Adachi, Noritaka; Kuratani, Shigeru

    2012-01-01

    Vertebrate head segmentation has attracted the attention of comparative and evolutionary morphologists for centuries, given its importance for understanding the developmental body plan of vertebrates and its evolutionary origin. In particular, the segmentation of the mesoderm is central to the problem. The shark embryo has provided a canonical morphological scheme of the head, with its epithelialized coelomic cavities (head cavities), which have often been regarded as head somites. To understand the evolutionary significance of the head cavities, the embryonic development of the mesoderm was investigated at the morphological and histological levels in the shark, Scyliorhinus torazame. Unlike somites and some enterocoelic mesodermal components in other vertebrates, the head cavities in S. torazame appeared as irregular cyst(s) in the originally unsegmented mesenchymal head mesoderm, and not via segmentation of an undivided coelom. The mandibular cavity appeared first in the paraxial part of the mandibular mesoderm, followed by the hyoid cavity, and the premandibular cavity was the last to form. The prechordal plate was recognized as a rhomboid roof of the preoral gut, continuous with the rostral notochord, and was divided anteroposteriorly into two parts by the growth of the hypothalamic primordium. Of those, the posterior part was likely to differentiate into the premandibular cavity, and the anterior part disappeared later. The head cavities and somites in the trunk exhibited significant differences, in terms of histological appearance and timing of differentiation. The mandibular cavity developed a rostral process secondarily; its homology to the anterior cavity reported in some elasmobranch embryos is discussed. © 2012 Wiley Periodicals, Inc.

  3. FoxA4 favours notochord formation by inhibiting contiguous mesodermal fates and restricts anterior neural development in Xenopus embryos.

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    Sabrina Murgan

    Full Text Available In vertebrates, the embryonic dorsal midline is a crucial signalling centre that patterns the surrounding tissues during development. Members of the FoxA subfamily of transcription factors are expressed in the structures that compose this centre. Foxa2 is essential for dorsal midline development in mammals, since knock-out mouse embryos lack a definitive node, notochord and floor plate. The related gene foxA4 is only present in amphibians. Expression begins in the blastula -chordin and -noggin expressing centre (BCNE and is later restricted to the dorsal midline derivatives of the Spemann's organiser. It was suggested that the early functions of mammalian foxa2 are carried out by foxA4 in frogs, but functional experiments were needed to test this hypothesis. Here, we show that some important dorsal midline functions of mammalian foxa2 are exerted by foxA4 in Xenopus. We provide new evidence that the latter prevents the respecification of dorsal midline precursors towards contiguous fates, inhibiting prechordal and paraxial mesoderm development in favour of the notochord. In addition, we show that foxA4 is required for the correct regionalisation and maintenance of the central nervous system. FoxA4 participates in constraining the prospective rostral forebrain territory during neural specification and is necessary for the correct segregation of the most anterior ectodermal derivatives, such as the cement gland and the pituitary anlagen. Moreover, the early expression of foxA4 in the BCNE (which contains precursors of the whole forebrain and most of the midbrain and hindbrain is directly required to restrict anterior neural development.

  4. FoxA4 favours notochord formation by inhibiting contiguous mesodermal fates and restricts anterior neural development in Xenopus embryos.

    Science.gov (United States)

    Murgan, Sabrina; Castro Colabianchi, Aitana Manuela; Monti, Renato José; Boyadjián López, Laura Elena; Aguirre, Cecilia E; Stivala, Ernesto González; Carrasco, Andrés E; López, Silvia L

    2014-01-01

    In vertebrates, the embryonic dorsal midline is a crucial signalling centre that patterns the surrounding tissues during development. Members of the FoxA subfamily of transcription factors are expressed in the structures that compose this centre. Foxa2 is essential for dorsal midline development in mammals, since knock-out mouse embryos lack a definitive node, notochord and floor plate. The related gene foxA4 is only present in amphibians. Expression begins in the blastula -chordin and -noggin expressing centre (BCNE) and is later restricted to the dorsal midline derivatives of the Spemann's organiser. It was suggested that the early functions of mammalian foxa2 are carried out by foxA4 in frogs, but functional experiments were needed to test this hypothesis. Here, we show that some important dorsal midline functions of mammalian foxa2 are exerted by foxA4 in Xenopus. We provide new evidence that the latter prevents the respecification of dorsal midline precursors towards contiguous fates, inhibiting prechordal and paraxial mesoderm development in favour of the notochord. In addition, we show that foxA4 is required for the correct regionalisation and maintenance of the central nervous system. FoxA4 participates in constraining the prospective rostral forebrain territory during neural specification and is necessary for the correct segregation of the most anterior ectodermal derivatives, such as the cement gland and the pituitary anlagen. Moreover, the early expression of foxA4 in the BCNE (which contains precursors of the whole forebrain and most of the midbrain and hindbrain) is directly required to restrict anterior neural development.

  5. Hoxd11 specifies a program of metanephric kidney development within the intermediate mesoderm of the mouse embryo.

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    Mugford, Joshua W; Sipilä, Petra; Kobayashi, Akio; Behringer, Richard R; McMahon, Andrew P

    2008-07-15

    The mammalian kidney consists of an array of tubules connected to a ductal system that collectively function to control water/salt balance and to remove waste from the organisms' circulatory system. During mammalian embryogenesis, three kidney structures form within the intermediate mesoderm. The two most anterior structures, the pronephros and the mesonephros, are transitory and largely non-functional, while the most posterior, the metanephros, persists as the adult kidney. We have explored the mechanisms underlying regional specific differentiation of the kidney forming mesoderm. Previous studies have shown a requirement for Hox11 paralogs (Hoxa11, Hoxc11 and Hoxd11) in metanephric development. Mice lacking all Hox11 activity fail to form metanephric kidney structures. We demonstrate that the Hox11 paralog expression is restricted in the intermediate mesoderm to the posterior, metanephric level. When Hoxd11 is ectopically activated in the anterior mesonephros, we observe a partial transformation to a metanephric program of development. Anterior Hoxd11(+) cells activate Six2, a transcription factor required for the maintenance of metanephric tubule progenitors. Additionally, Hoxd11(+) mesonephric tubules exhibit an altered morphology and activate several metanephric specific markers normally confined to distal portions of the functional nephron. Collectively, our data support a model where Hox11 paralogs specify a metanephric developmental program in responsive intermediate mesoderm. This program maintains tubule forming progenitors and instructs a metanephric specific pattern of nephron differentiation.

  6. A case of mesodermic mixed tumor of the uterus developing after the treatment of myoma with x-ray irradiation

    International Nuclear Information System (INIS)

    Hiura, Masamichi; Mano, Atsuo; Egawa, Kenshi; Katsube, Yasuhiro; Sasaki, Takahiro

    1975-01-01

    A case of mesodermic mixed tumor primarily developing in the endometrium was reported with some discussion. The anamnesis was interesting that the patient had been exposed to the secondary radioactivity of the atomic bomb in Hiroshima and to X-ray for the treatment of myoma. Histological examination revealed adenoma as the epithelial element and fibromyxoma-like tissues, cartilage tissues, vascular tissues, and endometrial interstitium-like tissues as the non-epithelial elements. (Chiba, N.)

  7. Case of mesodermic mixed tumor of the uterus developing after the treatment of myoma with x-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Hiura, M; Mano, A; Egawa, K; Katsube, Y; Sasaki, T [Hiroshima Univ. (Japan). School of Medicine

    1975-06-01

    A case of mesodermic mixed tumor primarily developing in the endometrium was reported with some discussion. The anamnesis was interesting that the patient had been exposed to the secondary radioactivity of the atomic bomb in Hiroshima and to X-ray for the treatment of myoma. Histological examination revealed adenoma as the epithelial element and fibromyxoma-like tissues, cartilage tissues, vascular tissues, and endometrial interstitium-like tissues as the non-epithelial elements.

  8. Cortical Development Requires Mesodermal Expression of Tbx1, a Gene Haploinsufficient in 22q11.2 Deletion Syndrome.

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    Flore, Gemma; Cioffi, Sara; Bilio, Marchesa; Illingworth, Elizabeth

    2017-03-01

    In mammals, proper temporal control of neurogenesis and neural migration during embryonic development ensures correct formation of the cerebral cortex. Changes in the distribution of cortical projection neurons and interneurons are associated with behavioral disorders and psychiatric diseases, including schizophrenia and autism, suggesting that disrupted cortical connectivity contributes to the brain pathology. TBX1 is the major candidate gene for 22q11.2 deletion syndrome (22q11.2DS), a chromosomal deletion disorder characterized by a greatly increased risk for schizophrenia. We have previously shown that Tbx1 heterozygous mice have reduced prepulse inhibition, a behavioral abnormality that is associated with 22q11.2DS and nonsyndromic schizophrenia. Here, we show that loss of Tbx1 disrupts corticogenesis in mice by promoting premature neuronal differentiation in the medio-lateral embryonic cortex, which gives rise to the somatosensory cortex (S1). In addition, we found altered polarity in both radially migrating excitatory neurons and tangentially migrating inhibitory interneurons. Together, these abnormalities lead to altered lamination in the S1 at the terminal stages of corticogenesis in Tbx1 null mice and similar anomalies in Tbx1 heterozygous adult mice. Finally, we show that mesoderm-specific inactivation of Tbx1 is sufficient to recapitulate the brain phenotype indicating that Tbx1 exerts a cell nonautonomous role in cortical development from the mesoderm. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  9. Sirenomelia in Bmp7 and Tsg compound mutant mice: requirement for Bmp signaling in the development of ventral posterior mesoderm.

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    Zakin, Lise; Reversade, Bruno; Kuroda, Hiroki; Lyons, Karen M; De Robertis, Eddy M

    2005-05-01

    Sirenomelia or mermaid-like phenotype is one of the principal human congenital malformations that can be traced back to the stage of gastrulation. Sirenomelia is characterized by the fusion of the two hindlimbs into a single one. In the mouse, sirens have been observed in crosses between specific strains and as the consequence of mutations that increase retinoic acid levels. We report that the loss of bone morphogenetic protein 7 (Bmp7) in combination with a half dose or complete loss of twisted gastrulation (Tsg) causes sirenomelia in the mouse. Tsg is a Bmp- and chordin-binding protein that has multiple effects on Bmp metabolism in the extracellular space; Bmp7 is one of many Bmps and is shown here to bind to Tsg. In Xenopus, co-injection of Tsg and Bmp7 morpholino oligonucleotides (MO) has a synergistic effect, greatly inhibiting formation of ventral mesoderm and ventral fin tissue. In the mouse, molecular marker studies indicate that the sirenomelia phenotype is associated with a defect in the formation of ventroposterior mesoderm. These experiments demonstrate that dorsoventral patterning of the mouse posterior mesoderm is regulated by Bmp signaling, as is the case in other vertebrates. Sirens result from a fusion of the hindlimb buds caused by a defect in the formation of ventral mesoderm.

  10. Effect of ABCD transformations on beam paraxiality.

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    Vaveliuk, Pablo; Martinez-Matos, Oscar

    2011-12-19

    The limits of the paraxial approximation for a laser beam under ABCD transformations is established through the relationship between a parameter concerning the beam paraxiality, the paraxial estimator, and the beam second-order moments. The applicability of such an estimator is extended to an optical system composed by optical elements as mirrors and lenses and sections of free space, what completes the analysis early performed for free-space propagation solely. As an example, the paraxiality of a system composed by free space and a spherical thin lens under the propagation of Hermite-Gauss and Laguerre-Gauss modes is established. The results show that the the paraxial approximation fails for a certain feasible range of values of main parameters. In this sense, the paraxial estimator is an useful tool to monitor the limits of the paraxial optics theory under ABCD transformations.

  11. Analysis of a Caenorhabditis elegans Twist homolog identifies conserved and divergent aspects of mesodermal patterning

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    Harfe, Brian D.; Gomes, Ana Vaz; Kenyon, Cynthia; Liu, Jun; Krause, Michael; Fire, Andrew

    1998-01-01

    Mesodermal development is a multistep process in which cells become increasingly specialized to form specific tissue types. In Drosophila and mammals, proper segregation and patterning of the mesoderm involves the bHLH factor Twist. We investigated the activity of a Twist-related factor, CeTwist, during Caenorhabditis elegans mesoderm development. Embryonic mesoderm in C. elegans derives from a number of distinct founder cells that are specified during the early lineages; in contrast, a singl...

  12. Modeling paraxial wave propagation in free-electron laser oscillators

    NARCIS (Netherlands)

    Karssenberg, J.G.; van der Slot, Petrus J.M.; Volokhine, I.; Verschuur, Jeroen W.J.; Boller, Klaus J.

    2006-01-01

    Modeling free-electron laser (FEL) oscillators requires calculation of both the light-beam interaction within the undulator and the light propagation outside the undulator. We have developed a paraxial optical propagation code that can be combined with various existing models of gain media, for

  13. The Appell transformation for the paraxial wave equation

    International Nuclear Information System (INIS)

    Torre, A

    2011-01-01

    Some issues related to the 1D heat equation are revisited and framed within the context of the free-space paraxial propagation, formally accounted for by the 2D paraxial wave equation. In particular, the Appell transformation, which is well known in the theory of the heat equation, is reformulated in optical terms, and accordingly interpreted in the light of the propagation of given source functions, which are in a definite relation with the source functions of the original wavefunctions. Basic to the discussion is the Lie-algebra-based approach, as developed in a series of seminal papers by Kalnins, Miller and Boyer, to evolutionary-type equations, ruled by Hamiltonian operators underlying a harmonic oscillator-like symmetry algebra. Indeed, both the heat equation and the paraxial wave equation are particular cases of this kind of equation. When interpreting such an approach in terms of the propagation of assigned 'source' functions, the transformations between wavefunctions may be traced back to definite relations between the respective source functions. Thus, the optical Appell transformation is seen to be a manifestation of the correspondence between wavefunctions generated by eigenstates of operators, which are linked through a Fourier-similarity transformation. As a mere consequence, one can introduce the fractional Appell transformation, thus displaying a family of symmetry transformations parameterized by a continuous parameter

  14. On beam models and their paraxial approximation

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    Waters, W. J.; King, B.

    2018-01-01

    We derive focused laser pulse solutions to the electromagnetic wave equation in vacuum. After reproducing beam and pulse expressions for the well-known paraxial Gaussian and axicon cases, we apply the method to analyse a laser beam with Lorentzian transverse momentum distribution. Whilst a paraxial approach has some success close to the focal axis and within a Rayleigh range of the focal spot, we find that it incorrectly predicts the transverse fall-off typical of a Lorentzian. Our vector-potential approach is particularly relevant to calculation of quantum electrodynamical processes in weak laser pulse backgrounds.

  15. Paraxial charge compensator for electron cryomicroscopy

    International Nuclear Information System (INIS)

    Berriman, John A.; Rosenthal, Peter B.

    2012-01-01

    We describe a multi-hole condenser aperture for the production of several electron beams in the transmission electron microscope (TEM) making it possible to simultaneously image and irradiate spatially separated regions of a specimen. When the specimen is a thin film of vitreous ice suspended over a holey carbon film, simultaneous irradiation of the adjacent carbon support with the off-axis beam compensates for some of the effects of charging in the image formed by a beam irradiating only the ice. Because the intervening region is not irradiated, charge-neutralization of frozen-hydrated specimens can occur by a through-space mechanism such as the emission of secondary electrons from a grounded carbon support film. We use paraxial charge compensation (PCC) to control the amount of charge build-up on the specimen and observe the effects of charge on images. The multi-hole aperture thus provides a tool for investigating the mechanism of charging and charge mitigation during the imaging of radiation sensitive biological specimens by cryomicroscopy. -- Highlights: ► A multi-hole condenser aperture produces multiple (paraxial) beams in TEM. ► Paraxial charge compensation is used to study electron-optical effects of charging. ► Emission of secondary electrons controls charging by a through space mechanism. ► Paraxial beams compensate for charging effects in frozen-hydrated specimens.

  16. Paraxial charge compensator for electron cryomicroscopy

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    Berriman, John A. [Division of Physical Biochemistry, MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London, NW7 1AA (United Kingdom); Rosenthal, Peter B., E-mail: peter.rosenthal@nimr.mrc.ac.uk [Division of Physical Biochemistry, MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London, NW7 1AA (United Kingdom)

    2012-05-15

    We describe a multi-hole condenser aperture for the production of several electron beams in the transmission electron microscope (TEM) making it possible to simultaneously image and irradiate spatially separated regions of a specimen. When the specimen is a thin film of vitreous ice suspended over a holey carbon film, simultaneous irradiation of the adjacent carbon support with the off-axis beam compensates for some of the effects of charging in the image formed by a beam irradiating only the ice. Because the intervening region is not irradiated, charge-neutralization of frozen-hydrated specimens can occur by a through-space mechanism such as the emission of secondary electrons from a grounded carbon support film. We use paraxial charge compensation (PCC) to control the amount of charge build-up on the specimen and observe the effects of charge on images. The multi-hole aperture thus provides a tool for investigating the mechanism of charging and charge mitigation during the imaging of radiation sensitive biological specimens by cryomicroscopy. -- Highlights: Black-Right-Pointing-Pointer A multi-hole condenser aperture produces multiple (paraxial) beams in TEM. Black-Right-Pointing-Pointer Paraxial charge compensation is used to study electron-optical effects of charging. Black-Right-Pointing-Pointer Emission of secondary electrons controls charging by a through space mechanism. Black-Right-Pointing-Pointer Paraxial beams compensate for charging effects in frozen-hydrated specimens.

  17. Limitations of the paraxial Debye approximation.

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    Sheppard, Colin J R

    2013-04-01

    In the paraxial form of the Debye integral for focusing, higher order defocus terms are ignored, which can result in errors in dealing with aberrations, even for low numerical aperture. These errors can be avoided by using a different integration variable. The aberrations of a glass slab, such as a coverslip, are expanded in terms of the new variable, and expressed in terms of Zernike polynomials to assist with aberration balancing. Tube length error is also discussed.

  18. Image transmission through a stable paraxial cavity

    International Nuclear Information System (INIS)

    Gigan, Sylvain; Lopez, Laurent; Treps, Nicolas; Maitre, Agnes; Fabre, Claude

    2005-01-01

    We study the transmission of a monochromatic 'image' through a paraxial cavity. Using the formalism of self-transform functions, we show that a transverse degenerate cavity transmits the self-transform part of the image, with respect to the field transformation over one round-trip of the cavity. This formalism gives insight into the understanding of the behavior of a transverse degenerate cavity, complementary to the transverse mode picture. An experiment of image transmission through a hemiconfocal cavity shows the interest of this approach

  19. Paraxial Green's functions in synchrotron radiation theory

    International Nuclear Information System (INIS)

    Geloni, G.; Saldin, E.; Scheidmiller, E.; Yurkov, M.

    2005-02-01

    This work contains a systematic treatment of single particle synchrotron radiation and some application to realistic beams with given cross section area, divergence and energy spread. Standard theory relies on several approximations whose applicability limits and accuracy are often forgotten. We begin remarking that on the one hand, a paraxial approximation can always be applied without loss of generality and with ultra relativistic accuracy. On the other hand, dominance of the acceleration field over the velocity part in the Lienard-Wiechert expressions is not always guaranteed and constitutes a separate assumption, whose applicability is discussed. Treating synchrotron radiation in paraxial approximation we derive the equation for the slow varying envelope function of the Fourier components of the electric field vector. Calculations of Synchrotron Radiation properties performed by others showed that the phase of the Fourier components of the electric field vector differs from the phase of a virtual point source. In this paper we present a systematic, analytical description of this phase shift, calculating amplitude and phase of electric field from bending magnets, short magnets, two bending magnet system separated by a straight section (edge radiation) and undulator devices. We pay particular attention to region of applicability and accuracy of approximations used. Finally, taking advantage of results of analytical calculation presented in reduced form we analyze various features of radiation from a complex insertion device (set of two undulators with a focusing triplet in between) accounting for the influence of energy spread and electron beam emittance. (orig.)

  20. Theory of the paraxial ion trajectory in the spiral inflector

    International Nuclear Information System (INIS)

    Toprek, Dragan

    2000-01-01

    This paper presents the analytical and numerical theory of the paraxial ion trajectory through the spiral inflector. Analytical expressions for the equations which describe the paraxial ion trajectory are derived. The analytical derivations of the electric field expansion around the central ion trajectory has also been studied

  1. Geometrical and wave optics of paraxial beams.

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    Meron, M; Viccaro, P J; Lin, B

    1999-06-01

    Most calculational techniques used to evaluate beam propagation are geared towards either fully coherent or fully incoherent beams. The intermediate partial-coherence regime, while in principle known for a long time, has received comparably little attention so far. The resulting shortage of adequate calculational techniques is currently being felt in the realm of x-ray optics where, with the advent of third generation synchrotron light sources, partially coherent beams become increasingly common. The purpose of this paper is to present a calculational approach which, utilizing a "variance matrix" representation of paraxial beams, allows for a straightforward evaluation of wave propagation through an optical system. Being capable of dealing with an arbitrary degree of coherence, this approach covers the whole range from wave to ray optics, in a seamless fashion.

  2. STRIP1, a core component of STRIPAK complexes, is essential for normal mesoderm migration in the mouse embryo.

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    Bazzi, Hisham; Soroka, Ekaterina; Alcorn, Heather L; Anderson, Kathryn V

    2017-12-19

    Regulated mesoderm migration is necessary for the proper morphogenesis and organ formation during embryonic development. Cell migration and its dependence on the cytoskeleton and signaling machines have been studied extensively in cultured cells; in contrast, remarkably little is known about the mechanisms that regulate mesoderm cell migration in vivo. Here, we report the identification and characterization of a mouse mutation in striatin-interacting protein 1 ( Strip1 ) that disrupts migration of the mesoderm after the gastrulation epithelial-to-mesenchymal transition (EMT). STRIP1 is a core component of the biochemically defined mammalian striatin-interacting phosphatases and kinase (STRIPAK) complexes that appear to act through regulation of protein phosphatase 2A (PP2A), but their functions in mammals in vivo have not been examined. Strip1 -null mutants arrest development at midgestation with profound disruptions in the organization of the mesoderm and its derivatives, including a complete failure of the anterior extension of axial mesoderm. Analysis of cultured mesoderm explants and mouse embryonic fibroblasts from null mutants shows that the mesoderm migration defect is correlated with decreased cell spreading, abnormal focal adhesions, changes in the organization of the actin cytoskeleton, and decreased velocity of cell migration. The results show that STRIPAK complexes are essential for cell migration and tissue morphogenesis in vivo. Copyright © 2017 the Author(s). Published by PNAS.

  3. Accurate expansion of cylindrical paraxial waves for its straightforward implementation in electromagnetic scattering

    International Nuclear Information System (INIS)

    Naserpour, Mahin; Zapata-Rodríguez, Carlos J.

    2018-01-01

    Highlights: • Paraxial beams are represented in a series expansion in terms of Bessel wave functions. • The coefficients of the series expansion can be analytically determined by using the pattern in the focal plane. • In particular, Gaussian beams and apertured wave fields have been critically examined. • This representation of the wave field is adequate for scattering problems with shaped beams. - Abstract: The evaluation of vector wave fields can be accurately performed by means of diffraction integrals, differential equations and also series expansions. In this paper, a Bessel series expansion which basis relies on the exact solution of the Helmholtz equation in cylindrical coordinates is theoretically developed for the straightforward yet accurate description of low-numerical-aperture focal waves. The validity of this approach is confirmed by explicit application to Gaussian beams and apertured focused fields in the paraxial regime. Finally we discuss how our procedure can be favorably implemented in scattering problems.

  4. Entire mesodermal mantle behaves as Spemann's organizer in dorsoanterior enhanced Xenopus laevis embryos

    International Nuclear Information System (INIS)

    Kao, K.R.; Elinson, R.P.

    1988-01-01

    The body plan of Xenopus laevis can be respecified by briefly exposing early cleavage stage embryos to lithium. Such embryos develop exaggerated dorsoanterior structures such as a radial eye and cement gland. In this paper, we demonstrate that the enhanced dorsoanterior phenotype results from an overcommitment of mesoderm to dorsoanterior mesoderm. Histological and immunohistochemical observations reveal that the embryos have a greatly enlarged notochord with very little muscle tissue. In addition, they develop a radial, beating heart, suggesting that lithium also specifies anterior mesoderm and pharyngeal endoderm. Randomly oriented diametrically opposed marginal zone grafts from lithium-treated embryos, when transplanted into ultraviolet (uv)-irradiated axis-deficient hosts, rescue dorsal axial structures. These transplantation experiments demonstrate that the entire marginal zone of the early gastrula consists of presumptive dorsal mesoderm. Vital dye marking experiments also indicate that the entire marginal zone maps to the prominent proboscis that is composed of chordamesoderm and represents the long axis of the embryo. These results suggest that lithium respecifies the mesoderm of Xenopus laevis embryos so that it differentiates into the Spemann organizer. We suggest that the origin of the dorsoanterior enhanced phenotypes generated by lithium and the dorsoanterior deficient phenotypes generated by uv irradiation are due to relative quantities of organizer. Our evidence demonstrates the existence of a continuum of body plan phenotypes based on this premise

  5. Paraxial diffractive elements for space-variant linear transforms

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    Teiwes, Stephan; Schwarzer, Heiko; Gu, Ben-Yuan

    1998-06-01

    Optical linear transform architectures bear good potential for future developments of very powerful hybrid vision systems and neural network classifiers. The optical modules of such systems could be used as pre-processors to solve complex linear operations at very high speed in order to simplify an electronic data post-processing. However, the applicability of linear optical architectures is strongly connected with the fundamental question of how to implement a specific linear transform by optical means and physical imitations. The large majority of publications on this topic focusses on the optical implementation of space-invariant transforms by the well-known 4f-setup. Only few papers deal with approaches to implement selected space-variant transforms. In this paper, we propose a simple algebraic method to design diffractive elements for an optical architecture in order to realize arbitrary space-variant transforms. The design procedure is based on a digital model of scalar, paraxial wave theory and leads to optimal element transmission functions within the model. Its computational and physical limitations are discussed in terms of complexity measures. Finally, the design procedure is demonstrated by some examples. Firstly, diffractive elements for the realization of different rotation operations are computed and, secondly, a Hough transform element is presented. The correct optical functions of the elements are proved in computer simulation experiments.

  6. Churchill regulates cell movement and mesoderm specification by repressing Nodal signaling

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    Mentzer Laura

    2007-11-01

    Full Text Available Abstract Background Cell movements are essential to the determination of cell fates during development. The zinc-finger transcription factor, Churchill (ChCh has been proposed to regulate cell fate by regulating cell movements during gastrulation in the chick. However, the mechanism of action of ChCh is not understood. Results We demonstrate that ChCh acts to repress the response to Nodal-related signals in zebrafish. When ChCh function is abrogated the expression of mesodermal markers is enhanced while ectodermal markers are expressed at decreased levels. In cell transplant assays, we observed that ChCh-deficient cells are more motile than wild-type cells. When placed in wild-type hosts, ChCh-deficient cells often leave the epiblast, migrate to the germ ring and are later found in mesodermal structures. We demonstrate that both movement of ChCh-compromised cells to the germ ring and acquisition of mesodermal character depend on the ability of the donor cells to respond to Nodal signals. Blocking Nodal signaling in the donor cells at the levels of Oep, Alk receptors or Fast1 inhibited migration to the germ ring and mesodermal fate change in the donor cells. We also detect additional unusual movements of transplanted ChCh-deficient cells which suggests that movement and acquisition of mesodermal character can be uncoupled. Finally, we demonstrate that ChCh is required to limit the transcriptional response to Nodal. Conclusion These data establish a broad role for ChCh in regulating both cell movement and Nodal signaling during early zebrafish development. We show that chch is required to limit mesodermal gene expression, inhibit Nodal-dependant movement of presumptive ectodermal cells and repress the transcriptional response to Nodal signaling. These findings reveal a dynamic role for chch in regulating cell movement and fate during early development.

  7. A Wave-Optics Approach to Paraxial Geometrical Laws Based on Continuity at Boundaries

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    Linares, J.; Nistal, M. C.

    2011-01-01

    We present a derivation of the paraxial geometrical laws starting from a wave-optics approach, in particular by using simple continuity conditions of paraxial spherical waves at boundaries (discontinuities) between optical media. Paraxial geometrical imaging and magnification laws, under refraction and reflection at boundaries, are derived for…

  8. Non-paraxial beam to push and pull microparticles

    DEFF Research Database (Denmark)

    Novitsky, Andrey; Qiu, C.-W.

    2011-01-01

    We discuss a feasibility of the pulling (backward) force acting on a spherical microparticle in a non-paraxial Bessel beam. The effect can be explained by the strong interaction of particle's multipoles or by the conservation of momentum in the system “photons-particle.” It is remarkable that the...

  9. Four and a half domain 2 (FHL2) scaffolding protein is a marker of connective tissues of developing digits and regulates fibrogenic differentiation of limb mesodermal progenitors.

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    Lorda-Diez, C I; Montero, J A; Sanchez-Fernandez, C; Garcia-Porrero, J A; Chimal-Monroy, J; Hurle, J M

    2018-04-01

    Four and a half LIM domain 2 (FHL2) is a multifunctional scaffolding protein of well-known function regulating cell signalling cascades and gene transcription in cancer tissues. However, its function in embryonic systems is poorly characterized. Here, we show that Fhl2 is involved in the differentiation of connective tissues of developing limb autopod. We show that Fhl2 exhibits spatially restricted and temporally dynamic expression around the tendons of developing digits, interphalangeal joint capsules, and fibrous peridigital tissue. Immunolabelling analysis of the skeletal progenitors identified a predominant, but not exclusive, cytoplasmic distribution of FHL2 being associated with focal adhesions and actin cytoskeleton. In the course of chondrogenic differentiation of cultures of limb skeletal progenitors, the expression of Fhl2 is down-regulated. Furthermore, cultures of skeletal progenitors overexpressing Fhl2 take on a predominant fibrogenic appearance. Both gain-of-function and loss-of-function experiments in the micromass culture assays revealed a positive transcriptional influence of Fhl2 in the expression of fibrogenic markers including Scleraxis, Tenomodulin, Tenascin C, βig-h3, and Tgif1. We further show that the expression of Fhl2 is positively regulated by profibrogenic signals including Tgfβ2, all-trans-retinoic acid, and canonical Wnt signalling molecules and negatively regulated by prochondrogenic factors of the bone morphogenetic protein family. Expression of Fhl2 is also regulated negatively in immobilized limbs, but this influence appears to be mediated by other connective tissue markers, such as Tgfβs and Scleraxis. Copyright © 2018 John Wiley & Sons, Ltd.

  10. Defective neuronal migration and inhibition of bipolar to multipolar transition of migrating neural cells by Mesoderm-Specific Transcript, Mest, in the developing mouse neocortex.

    Science.gov (United States)

    Ji, Liting; Bishayee, Kausik; Sadra, Ali; Choi, Seunghyuk; Choi, Wooyul; Moon, Sungho; Jho, Eek-Hoon; Huh, Sung-Oh

    2017-07-04

    Brain developmental disorders such as lissencephaly can result from faulty neuronal migration and differentiation during the formation of the mammalian neocortex. The cerebral cortex is a modular structure, where developmentally, newborn neurons are generated as a neuro-epithelial sheet and subsequently differentiate, migrate and organize into their final positions in the cerebral cortical plate via a process involving both tangential and radial migration. The specific role of Mest, an imprinted gene, in neuronal migration has not been previously studied. In this work, we reduced expression of Mest with in utero electroporation of neuronal progenitors in the developing embryonic mouse neocortex. Reduction of Mest levels by shRNA significantly reduced the number of neurons migrating to the cortical plate. Also, Mest-knockdown disrupted the transition of bipolar neurons into multipolar neurons migrating out of the sub-ventricular zone region. The migrating neurons also adopted a more tangential migration pattern upon knockdown of the Mest message, losing their potential to attach to radial glia cells, required for radial migration. The differentiation and migration properties of neurons via Wnt-Akt signaling were affected by Mest changes. In addition, miR-335, encoded in a Mest gene intron, was identified as being responsible for blocking the default tangential migration of the neurons. Our results suggest that Mest and its intron product, miR-335, play important roles in neuronal migration with Mest regulating the morphological transition of primary neurons required in the formation of the mammalian neocortex. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  11. Mesoderm layer formation in Xenopus and Drosophila gastrulation

    International Nuclear Information System (INIS)

    Winklbauer, Rudolf; Müller, H-Arno J

    2011-01-01

    During gastrulation, the mesoderm spreads out between ectoderm and endoderm to form a mesenchymal cell layer. Surprisingly the underlying principles of mesoderm layer formation are very similar in evolutionarily distant species like the fruit fly, Drosophila melanogaster, and the frog, Xenopus laevis, in which the molecular and the cellular basis of mesoderm layer formation have been extensively studied. Complementary expression of growth factors in the ectoderm and their receptors in the mesoderm act to orient cellular protrusive activities and direct cell movement, leading to radial cell intercalation and the spreading of the mesoderm layer. This mechanism is contrasted with generic physical mechanisms of tissue spreading that consider the adhesive and physical properties of the cells and tissues. Both mechanisms need to be integrated to orchestrate mesenchymal morphogenesis

  12. Mapping the Pairwise Choices Leading from Pluripotency to Human Bone, Heart, and Other Mesoderm Cell Types.

    Science.gov (United States)

    Loh, Kyle M; Chen, Angela; Koh, Pang Wei; Deng, Tianda Z; Sinha, Rahul; Tsai, Jonathan M; Barkal, Amira A; Shen, Kimberle Y; Jain, Rajan; Morganti, Rachel M; Shyh-Chang, Ng; Fernhoff, Nathaniel B; George, Benson M; Wernig, Gerlinde; Salomon, Rachel E A; Chen, Zhenghao; Vogel, Hannes; Epstein, Jonathan A; Kundaje, Anshul; Talbot, William S; Beachy, Philip A; Ang, Lay Teng; Weissman, Irving L

    2016-07-14

    Stem-cell differentiation to desired lineages requires navigating alternating developmental paths that often lead to unwanted cell types. Hence, comprehensive developmental roadmaps are crucial to channel stem-cell differentiation toward desired fates. To this end, here, we map bifurcating lineage choices leading from pluripotency to 12 human mesodermal lineages, including bone, muscle, and heart. We defined the extrinsic signals controlling each binary lineage decision, enabling us to logically block differentiation toward unwanted fates and rapidly steer pluripotent stem cells toward 80%-99% pure human mesodermal lineages at most branchpoints. This strategy enabled the generation of human bone and heart progenitors that could engraft in respective in vivo models. Mapping stepwise chromatin and single-cell gene expression changes in mesoderm development uncovered somite segmentation, a previously unobservable human embryonic event transiently marked by HOPX expression. Collectively, this roadmap enables navigation of mesodermal development to produce transplantable human tissue progenitors and uncover developmental processes. VIDEO ABSTRACT. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Accurate expansion of cylindrical paraxial waves for its straightforward implementation in electromagnetic scattering

    Science.gov (United States)

    Naserpour, Mahin; Zapata-Rodríguez, Carlos J.

    2018-01-01

    The evaluation of vector wave fields can be accurately performed by means of diffraction integrals, differential equations and also series expansions. In this paper, a Bessel series expansion which basis relies on the exact solution of the Helmholtz equation in cylindrical coordinates is theoretically developed for the straightforward yet accurate description of low-numerical-aperture focal waves. The validity of this approach is confirmed by explicit application to Gaussian beams and apertured focused fields in the paraxial regime. Finally we discuss how our procedure can be favorably implemented in scattering problems.

  14. Analysis of coelom development in the sea urchin Holopneustes purpurescens yielding a deuterostome body plan

    Directory of Open Access Journals (Sweden)

    Valerie B. Morris

    2016-03-01

    Full Text Available An analysis of early coelom development in the echinoid Holopneustes purpurescens yields a deuterostome body plan that explains the disparity between the pentameral plan of echinoderms and the bilateral plans of chordates and hemichordates, the three major phyla of the monophyletic deuterostomes. The analysis shows an early separation into a medial hydrocoele and lateral coelomic mesoderm with an enteric channel between them before the hydrocoele forms the pentameral plan of five primary podia. The deuterostome body plan thus has a single axial or medial coelom and a pair of lateral coeloms, all surrounding an enteric channel, the gut channel. Applied to the phyla, the medial coelom is the hydrocoele in echinoderms, the notochord in chordates and the proboscis coelom in hemichordates: the lateral coeloms are the coelomic mesoderm in echinoderms, the paraxial mesoderm in chordates and the lateral coeloms in hemichordates. The plan fits frog and chick development and the echinoderm fossil record, and predicts genes involved in coelomogenesis as the source of deuterostome macroevolution.

  15. Mesoderm Lineage 3D Tissue Constructs Are Produced at Large-Scale in a 3D Stem Cell Bioprocess.

    Science.gov (United States)

    Cha, Jae Min; Mantalaris, Athanasios; Jung, Sunyoung; Ji, Yurim; Bang, Oh Young; Bae, Hojae

    2017-09-01

    Various studies have presented different approaches to direct pluripotent stem cell differentiation such as applying defined sets of exogenous biochemical signals and genetic/epigenetic modifications. Although differentiation to target lineages can be successfully regulated, such conventional methods are often complicated, laborious, and not cost-effective to be employed to the large-scale production of 3D stem cell-based tissue constructs. A 3D-culture platform that could realize the large-scale production of mesoderm lineage tissue constructs from embryonic stem cells (ESCs) is developed. ESCs are cultured using our previously established 3D-bioprocess platform which is amenable to mass-production of 3D ESC-based tissue constructs. Hepatocarcinoma cell line conditioned medium is introduced to the large-scale 3D culture to provide a specific biomolecular microenvironment to mimic in vivo mesoderm formation process. After 5 days of spontaneous differentiation period, the resulting 3D tissue constructs are composed of multipotent mesodermal progenitor cells verified by gene and molecular expression profiles. Subsequently the optimal time points to trigger terminal differentiation towards cardiomyogenesis or osteogenesis from the mesodermal tissue constructs is found. A simple and affordable 3D ESC-bioprocess that can reach the scalable production of mesoderm origin tissues with significantly improved correspondent tissue properties is demonstrated. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Nonparaxial and paraxial focusing of azimuthal-variant vector beams.

    Science.gov (United States)

    Gu, Bing; Cui, Yiping

    2012-07-30

    Based on the vectorial Rayleigh-Sommerfeld formulas under the weak nonparaxial approximation, we investigate the propagation behavior of a lowest-order Laguerre-Gaussian beam with azimuthal-variant states of polarization. We present the analytical expressions for the radial, azimuthal, and longitudinal components of the electric field with an arbitrary integer topological charge m focused by a nonaperturing thin lens. We illustrate the three-dimensional optical intensities, energy flux distributions, beam waists, and focal shifts of the focused azimuthal-variant vector beams under the nonparaxial and paraxial approximations.

  17. Knockout of the PKN Family of Rho Effector Kinases Reveals a Non-redundant Role for PKN2 in Developmental Mesoderm Expansion

    Directory of Open Access Journals (Sweden)

    Ivan Quétier

    2016-01-01

    Full Text Available In animals, the protein kinase C (PKC family has expanded into diversely regulated subgroups, including the Rho family-responsive PKN kinases. Here, we describe knockouts of all three mouse PKN isoforms and reveal that PKN2 loss results in lethality at embryonic day 10 (E10, with associated cardiovascular and morphogenetic defects. The cardiovascular phenotype was not recapitulated by conditional deletion of PKN2 in endothelial cells or the developing heart. In contrast, inducible systemic deletion of PKN2 after E7 provoked collapse of the embryonic mesoderm. Furthermore, mouse embryonic fibroblasts, which arise from the embryonic mesoderm, depend on PKN2 for proliferation and motility. These cellular defects are reflected in vivo as dependence on PKN2 for mesoderm proliferation and neural crest migration. We conclude that failure of the mesoderm to expand in the absence of PKN2 compromises cardiovascular integrity and development, resulting in lethality.

  18. A novel serum-free monolayer culture for orderly hematopoietic differentiation of human pluripotent cells via mesodermal progenitors.

    Directory of Open Access Journals (Sweden)

    Akira Niwa

    Full Text Available Elucidating the in vitro differentiation of human embryonic stem (ES and induced pluripotent stem (iPS cells is important for understanding both normal and pathological hematopoietic development in vivo. For this purpose, a robust and simple hematopoietic differentiation system that can faithfully trace in vivo hematopoiesis is necessary. In this study, we established a novel serum-free monolayer culture that can trace the in vivo hematopoietic pathway from ES/iPS cells to functional definitive blood cells via mesodermal progenitors. Stepwise tuning of exogenous cytokine cocktails induced the hematopoietic mesodermal progenitors via primitive streak cells. These progenitors were then differentiated into various cell lineages depending on the hematopoietic cytokines present. Moreover, single cell deposition assay revealed that common bipotential hemoangiogenic progenitors were induced in our culture. Our system provides a new, robust, and simple method for investigating the mechanisms of mesodermal and hematopoietic differentiation.

  19. A fetus with hemifacial microsomia and sirenomelia. The same mesodermal defect spectrum?

    Science.gov (United States)

    López-Valdez, Jaime Asael; Estrada-Juárez, Higinio; Moreno-Verduzco, Elsa Romelia; Aguinaga-Ríos, Mónica

    2013-04-01

    Sirenomelia is the most severe malformation complex affecting the human caudal pole, although its etiology is unclear, a primary defect of blastogenesis has been proposed. Studies consider sirenomelia as the most severe form of caudal dysgenesis, VACTERL association, or axial mesodermal dysplasia, although others still support the idea of a different pathologic entity. We report the prenatal, clinical, and pathologic features of a fetus with cleft lip and palate, microtia, cardiac, renal and intestinal malformations, radial aplasia, and sirenomelia. Karyotype, chromosomal breakage studies, and SHH sequence analysis were normal. The occurrence of cephalic, midline-paramedial, and caudal malformations in the same patient imply the diagnosis of hemifacial microsomia and sirenomelia. These entities are part of the same mesodermal malformation spectrum and the clinical presentation depends on environmental and genetic interactions in embrionic development. Future clinical and genome wide studies will help to better delineate this spectrum.

  20. Specification of Drosophila corpora cardiaca neuroendocrine cells from mesoderm is regulated by Notch signaling.

    Directory of Open Access Journals (Sweden)

    Sangbin Park

    2011-08-01

    Full Text Available Drosophila neuroendocrine cells comprising the corpora cardiaca (CC are essential for systemic glucose regulation and represent functional orthologues of vertebrate pancreatic α-cells. Although Drosophila CC cells have been regarded as developmental orthologues of pituitary gland, the genetic regulation of CC development is poorly understood. From a genetic screen, we identified multiple novel regulators of CC development, including Notch signaling factors. Our studies demonstrate that the disruption of Notch signaling can lead to the expansion of CC cells. Live imaging demonstrates localized emergence of extra precursor cells as the basis of CC expansion in Notch mutants. Contrary to a recent report, we unexpectedly found that CC cells originate from head mesoderm. We show that Tinman expression in head mesoderm is regulated by Notch signaling and that the combination of Daughterless and Tinman is sufficient for ectopic CC specification in mesoderm. Understanding the cellular, genetic, signaling, and transcriptional basis of CC cell specification and expansion should accelerate discovery of molecular mechanisms regulating ontogeny of organs that control metabolism.

  1. The lateral mesodermal divide: an epigenetic model of the origin of paired fins.

    Science.gov (United States)

    Nuño de la Rosa, Laura; Müller, Gerd B; Metscher, Brian D

    2014-01-01

    By examining development at the level of tissues and processes, rather than focusing on gene expression, we have formulated a general hypothesis to explain the dorso-ventral and anterior-posterior placement of paired appendage initiation sites in vertebrates. According to our model, the number and position of paired appendages are due to a commonality of embryonic tissue environments determined by the global interactions involving the two separated layers (somatic and visceral) of lateral plate mesoderm along the dorso-ventral and anterior-posterior axes of the embryo. We identify this distribution of developmental conditions, as modulated by the separation/contact of the two LPM layers and their interactions with somitic mesoderm, ectoderm, and endoderm as a dynamic developmental entity which we have termed the lateral mesodermal divide (LMD). Where the divide results in a certain tissue environment, fin bud initiation can occur. According to our hypothesis, the influence of the developing gut suppresses limb initiation along the midgut region and the ventral body wall owing to an "endodermal predominance." From an evolutionary perspective, the lack of gut regionalization in agnathans reflects the ancestral absence of these conditions, and the elaboration of the gut together with the concomitant changes to the LMD in the gnathostomes could have led to the origin of paired fins. © 2013 Wiley Periodicals, Inc.

  2. Post-hatching development of the porcine and bovine embryo-defining criteria for expected development in vivo and in vitro

    DEFF Research Database (Denmark)

    Vejlsted, Morten; Du, Yutao; Vajta, Gábor

    2006-01-01

    ) Somite stage(s) where paraxial mesoderm gradually condensates to form somites. Post-hatching development of bovine embryos in vitro is compromised and although hatching occurs and elongation can be physically provoked by culture in agarose tunnels, the embryonic disk characterizing the pre-streak stage 1......Particular attention has been paid to the pre-hatching period of embryonic development although blastocyst development is a poor indicator of embryo viability. Post-hatching embryonic dev elopment in vitro would allow for establishment of more accurate tools for evaluating developmental potential...... without the need for transfer to recipient animals. Such a system would require (1) definition of milestones of expected post-hatching embryonic development in vivo; and (2) development of adequate culture systems. We propose a stereomicroscopical staging system for post-hatching embryos defining...

  3. The Validity of a Paraxial Approximation in the Simulation of Laser Plasma Interactions

    International Nuclear Information System (INIS)

    Hyole, E. M.

    2000-01-01

    The design of high-power lasers such as those used for inertial confinement fusion demands accurate modeling of the interaction between lasers and plasmas. In inertial confinement fusion, initial laser pulses ablate material from the hohlraum, which contains the target, creating a plasma. Plasma density variations due to plasma motion, ablating material and the ponderomotive force exerted by the laser on the plasma disrupt smooth laser propagation, undesirably focusing and scattering the light. Accurate and efficient computational simulations aid immensely in developing an understanding of these effects. In this paper, we compare the accuracy of two methods for calculating the propagation of laser light through plasmas. A full laser-plasma simulation typically consists of a fluid model for the plasma motion and a laser propagation model. These two pieces interact with each other as follows. First, given the plasma density, one propagates the laser with a refractive index determined by this density. Then, given the laser intensities, the calculation of one time step of the plasma motion provides a new density for the laser propagation. Because this procedure repeats over many time steps, each piece must be performed accurately and efficiently. In general, calculation of the light intensities necessitates the solution of the Helmholtz equation with a variable index of refraction. The Helmholtz equation becomes extremely difficult and time-consuming to solve as the problem size increases. The size of laser-plasma problems of present interest far exceeds current capabilities. To avoid solving the full Helmholtz equation one may use a partial approximation. Generally speaking the partial approximation applies when one expects negligible backscattering of the light and only mild scattering transverse to the direction of light propagation. This approximation results in a differential equation that is first-order in the propagation direction that can be integrated

  4. Fast modal simulation of paraxial optical systems: the MIST open source toolbox

    International Nuclear Information System (INIS)

    Vajente, Gabriele

    2013-01-01

    This paper presents a new approach to the simulation of optical laser systems in the paraxial approximation, with particular applications to interferometric gravitational wave detectors. The method presented here is based on a standard decomposition of the laser field in terms of Hermite–Gauss transverse modes. The innovative feature consists of a symbolic manipulation of the equations describing the field propagation. This approach allows a huge reduction in the computational time, especially when a large number of higher order modes is needed to properly simulate the system. The new algorithm has been implemented in an open source toolbox, called the MIST, based on the MATLAB® environment. The MIST has been developed and is being used in the framework of the design of advanced gravitational wave detectors. Examples from this field of application will be discussed to illustrate the capabilities and performance of the simulation tool. (paper)

  5. Propagation of the Lissajous singularity dipole emergent from non-paraxial polychromatic beams

    Science.gov (United States)

    Haitao, Chen; Gao, Zenghui; Wang, Wanqing

    2017-06-01

    The propagation of the Lissajous singularity dipole (LSD) emergent from the non-paraxial polychromatic beams is studied. It is found that the handedness reversal of Lissajous singularities, the change in the shape of Lissajous figures, as well as the creation and annihilation of the LSD may take place by varying the propagation distance, off-axis parameter, wavelength, or amplitude factor. Comparing with the LSD emergent from paraxial polychromatic beams, the output field of non-paraxial polychromatic beams is more complicated, which results in some richer dynamic behaviors of Lissajous singularities, such as more Lissajous singularities and no vanishing of a single Lissajous singularity at the plane z>0.

  6. File list: Oth.Emb.10.AllAg.Pre-somitic_mesoderm [Chip-atlas[Archive

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  8. Integral superposition of paraxial Gaussian beams in inhomogeneous anisotropic layered structures in Cartesian coordinates

    Czech Academy of Sciences Publication Activity Database

    Červený, V.; Pšenčík, Ivan

    2015-01-01

    Roč. 25, - (2015), s. 109-155 ISSN 2336-3827 Institutional support: RVO:67985530 Keywords : integral superposition of paraxial Gaussian beams * inhomogeneous anisotropic media * S waves in weakly anisotropic media Subject RIV: DC - Siesmology, Volcanology, Earth Structure

  9. Radiological findings in three cases of paraxial radial hemimelia in goats

    International Nuclear Information System (INIS)

    Corbera, J.A.; Pulido, M.; Morales, M.; Juste, M.C.; Gutierrez, C.

    2002-01-01

    Hemimelia is a congenital abnormality characterized by the absence of a portion of the normal structures in a limb. Hemimelia is classified as transversal and paraxial and is related to genetical and environmental factors. This article shows the radiological findings observed in three different cases of paraxial hemimelia occurred in goats (radial agenesia, absence of the portion of the distal epiphysis of the radius and anomalous radius with ulnar hypoplasia). Possible causes related to these abnormalities are discussed

  10. TET2 deficiency inhibits mesoderm and hematopoietic differentiation in human embryonic stem cells

    DEFF Research Database (Denmark)

    Langlois, Thierry; da Costa Reis Monte Mor, Barbara; Lenglet, Gaëlle

    2014-01-01

    . Here, we show that TET2 expression is low in human embryonic stem (ES) cell lines and increases during hematopoietic differentiation. ShRNA-mediated TET2 knockdown had no effect on the pluripotency of various ES cells. However, it skewed their differentiation into neuroectoderm at the expense...... profile, including abnormal expression of neuronal genes. Intriguingly, when TET2 was knockdown in hematopoietic cells, it increased hematopoietic development. In conclusion, our work suggests that TET2 is involved in different stages of human embryonic development, including induction of the mesoderm...... and hematopoietic differentiation. Stem Cells 2014....

  11. Magnetic effects in the paraxial regime of elastic electron scattering

    Science.gov (United States)

    Edström, Alexander; Lubk, Axel; Rusz, Ján

    2016-11-01

    Motivated by a recent claim [Phys. Rev. Lett. 116, 127203 (2016), 10.1103/PhysRevLett.116.127203] that electron vortex beams can be used to image magnetism at the nanoscale in elastic scattering experiments, using transmission electron microscopy, a comprehensive computational study is performed to study magnetic effects in the paraxial regime of elastic electron scattering in magnetic solids. Magnetic interactions from electron vortex beams, spin polarized electron beams, and beams with phase aberrations are considered, as they pass through ferromagnetic FePt or antiferromagnetic LaMnAsO. The magnetic signals are obtained by comparing the intensity over a disk in the diffraction plane for beams with opposite angular momentum or aberrations. The strongest magnetic signals are obtained from vortex beams with large orbital angular momentum, where relative magnetic signals above 10-3 are indicated for 10 ℏ orbital angular momentum, meaning that relative signals of one percent could be expected with the even larger orbital angular momenta, which have been produced in experimental setups. All results indicate that beams with low acceleration voltage and small convergence angles yield stronger magnetic signals, which is unfortunately problematic for the possibility of high spatial resolution imaging. Nevertheless, under atomic resolution conditions, relative magnetic signals in the order of 10-4 are demonstrated, corresponding to an increase with one order of magnitude compared to previous work.

  12. Determination of the paraxial focal length using Zernike polynomials over different apertures

    Science.gov (United States)

    Binkele, Tobias; Hilbig, David; Henning, Thomas; Fleischmann, Friedrich

    2017-02-01

    The paraxial focal length is still the most important parameter in the design of a lens. As presented at the SPIE Optics + Photonics 2016, the measured focal length is a function of the aperture. The paraxial focal length can be found when the aperture approaches zero. In this work, we investigate the dependency of the Zernike polynomials on the aperture size with respect to 3D space. By this, conventional wavefront measurement systems that apply Zernike polynomial fitting (e.g. Shack-Hartmann-Sensor) can be used to determine the paraxial focal length, too. Since the Zernike polynomials are orthogonal over a unit circle, the aperture used in the measurement has to be normalized. By shrinking the aperture and keeping up with the normalization, the Zernike coefficients change. The relation between these changes and the paraxial focal length are investigated. The dependency of the focal length on the aperture size is derived analytically and evaluated by simulation and measurement of a strong focusing lens. The measurements are performed using experimental ray tracing and a Shack-Hartmann-Sensor. Using experimental ray tracing for the measurements, the aperture can be chosen easily. Regarding the measurements with the Shack-Hartmann- Sensor, the aperture size is fixed. Thus, the Zernike polynomials have to be adapted to use different aperture sizes by the proposed method. By doing this, the paraxial focal length can be determined from the measurements in both cases.

  13. Calculation of coherent synchrotron radiation in toroidal waveguides by paraxial wave equation

    Directory of Open Access Journals (Sweden)

    D. R. Gillingham

    2007-05-01

    Full Text Available A new technique for the simulation of coherent synchrotron radiation (CSR and space-charge fields from a single electron bunch in straight or toroidal rectangular waveguide sections has been developed. It is based on the integration of the paraxial approximation to the wave equations, using the perturbation technique where the bending radius is large compared to the dimension of the waveguide. We have implemented an unconditionally stable integration method in the time domain with transparent boundary conditions that allows the use of a minimally sized computational domain about the bunch. This technique explicitly enforces the causality condition so that no portion of the fields can propagate faster than the speed of light, can be used with arbitrary three-dimensional charge distributions, and contains corrections for finite energy. We have also developed a method for the calculation of the transverse forces within the bunch including space-charge. This method has been developed for incorporation with a particle-in-cell code so that we may self-consistently model CSR and space-charge in combinations of bending sections with a fully dynamic electron bunch in an efficient manner. In this paper we describe the model and methods for calculation of the fields in detail and compare results to theory wherever possible.

  14. Gata4 expression in lateral mesoderm is downstream of BMP4 and isactivated directly by Forkhead and GATA transcription factors through adistal enhancer element

    Energy Technology Data Exchange (ETDEWEB)

    Rojas, Anabel; De Val, Sarah; Heidt, Analeah B.; Xu, Shan-Mei; Bristow, James; Black, Brian L.

    2005-05-20

    The GATA family of zinc-finger transcription factors plays key roles in the specification and differentiation of multiple cell types during development. GATA4 is an early regulator of gene expression during the development of endoderm and mesoderm, and genetic studies in mice have demonstrated that GATA4 is required for embryonic development.Despite the importance of GATA4 in tissue specification and differentiation, the mechanisms by which Gata4 expression is activated and the transcription factor pathways upstream of GATA4 remain largely undefined. To identify transcriptional regulators of Gata4 in the mouse,we screened conserved noncoding sequences from the mouse Gata4 gene for enhancer activity in transgenic embryos. Here, we define the regulation of a distal enhancer element from Gata4 that is sufficient to direct expression throughout the lateral mesoderm, beginning at 7.5 days of mouse embryonic development. The activity of this enhancer is initially broad but eventually becomes restricted to the mesenchyme surrounding the liver. We demonstrate that the function of this enhancer in transgenic embryos is dependent upon highly conserved Forkhead and GATA transcription factor binding sites, which are bound by FOXF1 and GATA4,respectively. Furthermore, the activity of the Gata4 lateral mesoderm enhancer is attenuated by the BMP antagonist Noggin, and the enhancer is not activated in Bmp4-null embryos. Thus, these studies establish that Gata4 is a direct transcriptional target of Forkhead and GATA transcription factors in the lateral mesoderm, and demonstrate that Gata4lateral mesoderm enhancer activation requires BMP4, supporting a model in which GATA4 serves as a downstream effector of BMP signaling in the lateral mesoderm.

  15. In Ovo Electroporation for Targeting the Somitic Mesoderm

    Science.gov (United States)

    Ohata, Emi; Takahashi, Yoshiko

    The somite is a transient structure present in early vertebrate embryos, giving rise to a variety of essential tissues including skeletal muscles, dermis, axial bones and blood vessels. The term “somite” refers to a tissue of spherical structure that forms by pinching off from the continuous tissue called presomitic mesoderm (PSM, also called segmental plate in avian embryos). The PSM is recognized as a pair of longitudinal stripes along the midline of the body. Thus, each somite forms at the anterior end of PSM, and this process recurs periodically in time and space, gener ating the segmented pattern of the body along the antero-posterior axis.

  16. Photonic-Doppler-Velocimetry, Paraxial-Scalar Diffraction Theory and Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Ambrose, W. P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-07-20

    In this report I describe current progress on a paraxial, scalar-field theory suitable for simulating what is measured in Photonic Doppler Velocimetry (PDV) experiments in three dimensions. I have introduced a number of approximations in this work in order to bring the total computation time for one experiment down to around 20 hours. My goals were: to develop an approximate method of calculating the peak frequency in a spectral sideband at an instant of time based on an optical diffraction theory for a moving target, to compare the ‘measured’ velocity to the ‘input’ velocity to gain insights into how and to what precision PDV measures the component of the mass velocity along the optical axis, and to investigate the effects of small amounts of roughness on the measured velocity. This report illustrates the progress I have made in describing how to perform such calculations with a full three dimensional picture including tilted target, tilted mass velocity (not necessarily in the same direction), and small amounts of surface roughness. With the method established for a calculation at one instant of time, measured velocities can be simulated for a sequence of times, similar to the process of sampling velocities in experiments. Improvements in these methods are certainly possible at hugely increased computational cost. I am hopeful that readers appreciate the insights possible at the current level of approximation.

  17. Fusion of the SUMO/Sentrin-specific protease 1 gene SENP1 and the embryonic polarity-related mesoderm development gene MESDC2 in a patient with an infantile teratoma and a constitutional t(12;15)(q13;q25).

    NARCIS (Netherlands)

    Veltman, I.M.; Basten-Vreede, L.A.J.; Cheng, J.; Looijenga, L.H.J.; Janssen, H.A.P.; Schoenmakers, E.F.P.M.; Yeh, E.T.; Geurts van Kessel, A.H.M.

    2005-01-01

    Recently, we identified a patient with an infantile sacrococcygeal teratoma and a constitutional t(12;15)(q13;q25). Here, we show that, as a result of this chromosomal translocation, the SUMO/Sentrin-specific protease 1 gene (SENP1) on chromosome 12 and the embryonic polarity-related mesoderm

  18. Ectopic expression of Msx-2 in posterior limb bud mesoderm impairs limb morphogenesis while inducing BMP-4 expression, inhibiting cell proliferation, and promoting apoptosis.

    Science.gov (United States)

    Ferrari, D; Lichtler, A C; Pan, Z Z; Dealy, C N; Upholt, W B; Kosher, R A

    1998-05-01

    During early stages of chick limb development, the homeobox-containing gene Msx-2 is expressed in the mesoderm at the anterior margin of the limb bud and in a discrete group of mesodermal cells at the midproximal posterior margin. These domains of Msx-2 expression roughly demarcate the anterior and posterior boundaries of the progress zone, the highly proliferating posterior mesodermal cells underneath the apical ectodermal ridge (AER) that give rise to the skeletal elements of the limb and associated structures. Later in development as the AER loses its activity, Msx-2 expression expands into the distal mesoderm and subsequently into the interdigital mesenchyme which demarcates the developing digits. The domains of Msx-2 expression exhibit considerably less proliferation than the cells of the progress zone and also encompass several regions of programmed cell death including the anterior and posterior necrotic zones and interdigital mesenchyme. We have thus suggested that Msx-2 may be in a regulatory network that delimits the progress zone by suppressing the morphogenesis of the regions of the limb mesoderm in which it is highly expressed. In the present study we show that ectopic expression of Msx-2 via a retroviral expression vector in the posterior mesoderm of the progress zone from the time of initial formation of the limb bud severely impairs limb morphogenesis. Msx-2-infected limbs are typically very narrow along the anteroposterior axis, are occasionally truncated, and exhibit alterations in the pattern of formation of skeletal elements, indicating that as a consequence of ectopic Msx-2 expression the morphogenesis of large portions of the posterior mesoderm has been suppressed. We further show that Msx-2 impairs limb morphogenesis by reducing cell proliferation and promoting apoptosis in the regions of the posterior mesoderm in which it is ectopically expressed. The domains of ectopic Msx-2 expression in the posterior mesoderm also exhibit ectopic

  19. Delayed Mesoderm and Erythroid Differentiation of Murine Embryonic Stem Cells in the Absence of the Transcriptional Regulator FUBP1

    Directory of Open Access Journals (Sweden)

    Josephine Wesely

    2017-01-01

    Full Text Available The transcriptional regulator far upstream binding protein 1 (FUBP1 is essential for fetal and adult hematopoietic stem cell (HSC self-renewal, and the constitutive absence of FUBP1 activity during early development leads to embryonic lethality in homozygous mutant mice. To investigate the role of FUBP1 in murine embryonic stem cells (ESCs and in particular during differentiation into hematopoietic lineages, we generated Fubp1 knockout (KO ESC clones using CRISPR/Cas9 technology. Although FUBP1 is expressed in undifferentiated ESCs and during spontaneous differentiation following aggregation into embryoid bodies (EBs, absence of FUBP1 did not affect ESC maintenance. Interestingly, we observed a delayed differentiation of FUBP1-deficient ESCs into the mesoderm germ layer, as indicated by impaired expression of several mesoderm markers including Brachyury at an early time point of ESC differentiation upon aggregation to EBs. Coculture experiments with OP9 cells in the presence of erythropoietin revealed a diminished differentiation capacity of Fubp1 KO ESCs into the erythroid lineage. Our data showed that FUBP1 is important for the onset of mesoderm differentiation and maturation of hematopoietic progenitor cells into the erythroid lineage, a finding that is supported by the phenotype of FUBP1-deficient mice.

  20. Time-dependent field equations for paraxial relativistic electron beams: Beam Research Program

    International Nuclear Information System (INIS)

    Sharp, W.M.; Yu, S.S.; Lee, E.P.

    1987-01-01

    A simplified set of field equations for a paraxial relativistic electron beam is presented. These equations for the beam electrostatic potential phi and pinch potential Phi identical to A/sub z/ - phi retain previously neglected time-dependent terms and for axisymmetric beams reduce exactly to Maxwell's equations

  1. Simultaneous occurrence of a supra- and an infratentorial glioma in a patient with Ollier's disease : more evidence for non-mesodermal tumor predisposition in multiple enchondromatosis

    NARCIS (Netherlands)

    Heeg, M; Klein, JP; Krikke, AP

    1998-01-01

    A case is presented in which two neuro-ectodermal tumors, an infra- and a supratentorial glioma, developed in a young man with multiple enchondromatosis of Ollier's disease. This is the third such case of multifocal low-grade glioma in Ollier's disease, suggesting a predisposition for non-mesodermal

  2. File list: InP.Emb.50.AllAg.Pre-somitic_mesoderm [Chip-atlas[Archive

    Lifescience Database Archive (English)

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    Lifescience Database Archive (English)

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    Lifescience Database Archive (English)

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  8. File list: NoD.Emb.20.AllAg.Pre-somitic_mesoderm [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  9. Fox (forkhead) genes are involved in the dorso-ventral patterning of the Xenopus mesoderm.

    Science.gov (United States)

    El-Hodiri, H; Bhatia-Dey, N; Kenyon, K; Ault, K; Dirksen, M; Jamrich, M

    2001-01-01

    Fox (forkhead/winged helix) genes encode a family of transcription factors that are involved in embryonic pattern formation, regulation of tissue specific gene expression and tumorigenesis. Several of them are transcribed during Xenopus embryogenesis and are important for the patterning of ectoderm, mesoderm and endoderm. We have isolated three forkhead genes that are activated during gastrulation and play an important role in the dorso-ventral patterning of the mesoderm. XFKH1 (FoxA4b), the first vertebrate forkhead gene to be implicated in embryonic pattern formation, is expressed in the Spemann-Mangold organizer region and later in the embryonic notochord. XFKH7, the Xenopus orthologue of the murine Mfh1(Foxc2), is expressed in the presomitic mesoderm, but not in the notochord or lateral plate mesoderm. Finally, XFD-13'(FoxF1b)1 is expressed in the lateral plate mesoderm, but not in the notochord or presomitic mesoderm. Expression pattern and functional experiments indicate that these three forkhead genes are involved in the dorso-ventral patterning of the mesoderm.

  10. Contribution of mesoderm to the developing dental papilla

    Czech Academy of Sciences Publication Activity Database

    Rothová, Michaela; Feng, J.; Sharpe, P. T.; Peterková, Renata; Tucker, A. S.

    2011-01-01

    Roč. 55, č. 1 (2011), s. 59-64 ISSN 0214-6282 R&D Projects: GA ČR GA304/07/0223 Institutional research plan: CEZ:AV0Z50390512; CEZ:AV0Z50390703 Keywords : tooth * dental papilla * Mesp1cre Subject RIV: EA - Cell Biology Impact factor: 2.823, year: 2011

  11. Interference by amplitude division with extended sources by paraxial boundary conditions

    International Nuclear Information System (INIS)

    Liñares, J; Nistal, M C

    2014-01-01

    We present a wave-optics paraxial approach to the interference by amplitude division produced by plane-parallel films (or plates) and non-plane-parallel films, or by equivalent optical devices such as a Michelson interferometer, when they are illuminated with extended (spatially incoherent) quasi-monochromatic sources. To the best of our knowledge, the most common approaches to the study of interference are based, for simplicity, on the combined use of geometrical optics concepts, such as the optical path length along a ray, together with some wave-optics concepts such as optical phases. However, interference phenomena have been the means by which the wave nature of light has been established and therefore geometrical and wave concepts are so far-off that their simultaneous use can give rise to misleading concepts. Therefore, the primary aim of this work is to provide an analytical homogeneous description of interference by amplitude division using only paraxial spherical waves and boundary conditions at smooth interfaces or discontinuities in such a way that the calculation of the total optical field, interference irradiance, fringe visibility, coherence degree, localization of the interference and so on, can be made in a unified way by taking a fully wave-optics approach. The paraxial regime is enough in most cases and, moreover, interference is generally collected by an optical instrument such as a lens or the eye itself, in which a paraxial approximation is required. This work is particularly aimed at university physics teachers and undergraduate and first year postgraduate students. (papers)

  12. Purification and ex vivo expansion of postnatal human marrow mesodermal progenitor cells.

    Science.gov (United States)

    Reyes, M; Lund, T; Lenvik, T; Aguiar, D; Koodie, L; Verfaillie, C M

    2001-11-01

    It is here reported that mesenchymal stem cells known to give rise to limb-bud mesoderm can, at the single-cell level, also differentiate into cells of visceral mesoderm and can be expanded extensively by means of clinically applicable methods. These cells were named mesodermal progenitor cells (MPCs). MPCs were selected by depleting bone marrow mononuclear cells from more than 30 healthy human donors of CD45(+)/glycophorin-A (GlyA)(+) cells. Cells were cultured on fibronectin with epidermal growth factor and platelet-derived growth factor BB and 2% or less fetal calf serum. It was found that 1/5 x 10(3) CD45(-)GlyA(-) cells, or 1/10(6) bone marrow mononuclear cells, gave rise to clusters of small adherent cells. Cell-doubling time was 48 to 72 hours, and cells have been expanded in culture for more than 60 cell doublings. MPCs are CD34(-), CD44(low), CD45(-), CD117 (cKit)(-), class I-HLA(-), and HLA-DR(-). MPCs differentiated into cells of limb-bud mesoderm (osteoblasts, chondrocytes, adipocytes, stroma cells, and skeletal myoblasts) as well as visceral mesoderm (endothelial cells). Retroviral marking was used to definitively prove that single MPCs can differentiate into cells of limb bud and visceral mesoderm. Thus, MPCs that proliferate without obvious senescence under clinically applicable conditions and differentiate at the single-cell level not only into mesenchymal cells but also cells of visceral mesoderm may be an ideal source of stem cells for treatment of genetic or degenerative disorders affecting cells of mesodermal origin.

  13. Behavioural properties of chick somitic mesoderm and lateral plate when explanted in vitro.

    Science.gov (United States)

    Bellairs, R; Sanders, E J; Portch, P A

    1980-04-01

    Tissue culture, time-lapse cinematographic and electron microscopic techniques have been used to study the properties of chick mesoderm at several stages of differentiation. Lateral plate, unsegmented mesoderm (segmental plate), and newly formed somites were dissected from stage-12 embryos, whilst dermo-myotomes and sclerotomes were dissected from stage-18 embryos. Each type of mesoderm was found to exhibit a characteristic pattern of behaviour. The explants from the unsegmented mesoderm from the newly formed somites and from the older embryos could be placed in a developmental sequence; with increasing differentiation they settled and spread on the substrate more readily, whether explanted as pieces of tissue or as individual cells, and it was concluded that this implied an increased adhesion to the substrate. Similarly, with increasing differentiation, the cells segmented at a faster rate. No significant differences could be discerned in the internal structure of the different types of cells, although differences in the general shape were apparent. The lateral plate mesoderm cells, which bear some resemblances to the unsegmented mesoderm cells in the embryo, also show some morphological resemblances to them in vitro. However, the lateral plate cells had a much greater success in attaching to glass or platic substrates. They were also found to have the highest speed of locomotion of all the tissues studied, whereas the unsegmented had the lowest. It is concluded therefore, that although cells may look similar to one another morphologically, their behaviour may differ greatly, probably because they are already partially determined.

  14. Directional migration of leading-edge mesoderm generates physical forces: Implication in Xenopus notochord formation during gastrulation.

    Science.gov (United States)

    Hara, Yusuke; Nagayama, Kazuaki; Yamamoto, Takamasa S; Matsumoto, Takeo; Suzuki, Makoto; Ueno, Naoto

    2013-10-15

    Gastrulation is a dynamic tissue-remodeling process occurring during early development and fundamental to the later organogenesis. It involves both chemical signals and physical factors. Although much is known about the molecular pathways involved, the roles of physical forces in regulating cellular behavior and tissue remodeling during gastrulation have just begun to be explored. Here, we characterized the force generated by the leading edge mesoderm (LEM) that migrates preceding axial mesoderm (AM), and investigated the contribution of LEM during Xenopus gastrulation. First, we constructed an assay system using micro-needle which could measure physical forces generated by the anterior migration of LEM, and estimated the absolute magnitude of the force to be 20-80nN. Second, laser ablation experiments showed that LEM could affect the force distribution in the AM (i.e. LEM adds stretch force on axial mesoderm along anterior-posterior axis). Third, migrating LEM was found to be necessary for the proper gastrulation cell movements and the establishment of organized notochord structure; a reduction of LEM migratory activity resulted in the disruption of mediolateral cell orientation and convergence in AM. Finally, we found that LEM migration cooperates with Wnt/PCP to form proper notochord. These results suggest that the force generated by the directional migration of LEM is transmitted to AM and assists the tissue organization of notochord in vivo independently of the regulation by Wnt/PCP. We propose that the LEM may have a mechanical role in aiding the AM elongation through the rearrangement of force distribution in the dorsal marginal zone. © 2013 Elsevier Inc. All rights reserved.

  15. Molecular Mechanism of Somite Development

    Directory of Open Access Journals (Sweden)

    Gulfidan Coskun

    2013-06-01

    Full Text Available From third week of gestation, notochord and the neural folds begin to gather at the center of the embryo to form the paraxial mesoderm. Paraxial mesoderm separates into blocks of cells called somitomers at the lateral sides of the neural tube of the head region. At the beginning of the third week somitomeres take ring shapes and form blocks of somites from occipital region to caudal region. Although somites are transient structures, they are extremely important in organizing the segmental pattern of vertebrate embryos. Somites give rise to the cells that form the vertebrae and ribs, the dermis of the dorsal skin, the skeletal muscles of the back, and the skeletal muscles of the body wall and limbs. Somitogenesis are formed by a genetic mechanism that is regulated by cyclical expression of genes in the Notch, Wnt and fibroblast growth factor signaling pathways. The prevailing model of the mechanism governing somitogenesis is the “clock and wave front”. Somitogenesis has components of periodicity, separation, epithelialization and axial specification. According to this model, the clock causes cells to undergo repeated oscillations, with a particular phase of each oscillation defining the competency of cells in the presomitic mesoderm to form a somite. Any disruption in this mechanism can be cause of severe segmentation defects of the vertebrae and congenital anomalies. In this review, we discuss the molecular mechanisms underlying the somitogenesis which is an important part of morphogenesis. [Archives Medical Review Journal 2013; 22(3.000: 362-376

  16. Paraxial WKB solution of a scalar wave equation

    International Nuclear Information System (INIS)

    Pereverzev, G.V.

    1993-04-01

    An asymptotic method of solving a scalar wave equation in inhomogeneous media is developed. This method is an extension of the WKB method to the multidimensional case. It reduces a general wave equation to a set of ordinary differential equations similar to that of the eikonal approach and includes the latter as a particular case. However, the WKB method makes use of another kind of asymptotic expansion and, unlike the eikonal approach, describes the wave properties, i.e. diffraction and interference. At the same time, the three-dimensional WKB method is more simple for numerical treatment because the number of equations is less than in the eikonal approach. The method developed may be used for a calculation of wave fields in problems of RF heating, current drive and plasma diagnostics with microwave beams. (orig.)

  17. Paraxial design of an optical element with variable focal length and fixed position of principal planes.

    Science.gov (United States)

    Mikš, Antonín; Novák, Pavel

    2018-05-10

    In this article, we analyze the problem of the paraxial design of an active optical element with variable focal length, which maintains the positions of its principal planes fixed during the change of its optical power. Such optical elements are important in the process of design of complex optical systems (e.g., zoom systems), where the fixed position of principal planes during the change of optical power is essential for the design process. The proposed solution is based on the generalized membrane tunable-focus fluidic lens with several membrane surfaces.

  18. Transcription factor KLF7 regulates differentiation of neuroectodermal and mesodermal cell lineages

    International Nuclear Information System (INIS)

    Caiazzo, Massimiliano; Colucci-D'Amato, Luca; Esposito, Maria T.; Parisi, Silvia; Stifani, Stefano; Ramirez, Francesco; Porzio, Umberto di

    2010-01-01

    Previous gene targeting studies in mice have implicated the nuclear protein Krueppel-like factor 7 (KLF7) in nervous system development while cell culture assays have documented its involvement in cell cycle regulation. By employing short hairpin RNA (shRNA)-mediated gene silencing, here we demonstrate that murine Klf7 gene expression is required for in vitro differentiation of neuroectodermal and mesodermal cells. Specifically, we show a correlation of Klf7 silencing with down-regulation of the neuronal marker microtubule-associated protein 2 (Map2) and the nerve growth factor (NGF) tyrosine kinase receptor A (TrkA) using the PC12 neuronal cell line. Similarly, KLF7 inactivation in Klf7-null mice decreases the expression of the neurogenic marker brain lipid-binding protein/fatty acid-binding protein 7 (BLBP/FABP7) in neural stem cells (NSCs). We also report that Klf7 silencing is detrimental to neuronal and cardiomyocytic differentiation of embryonic stem cells (ESCs), in addition to altering the adipogenic and osteogenic potential of mouse embryonic fibroblasts (MEFs). Finally, our results suggest that genes that are key for self-renewal of undifferentiated ESCs repress Klf7 expression in ESCs. Together with previous findings, these results provide evidence that KLF7 has a broad spectrum of regulatory functions, which reflect the discrete cellular and molecular contexts in which this transcription factor operates.

  19. Transcription factor KLF7 regulates differentiation of neuroectodermal and mesodermal cell lineages

    Energy Technology Data Exchange (ETDEWEB)

    Caiazzo, Massimiliano, E-mail: caiazzo@igb.cnr.it [Institute of Genetics and Biophysics ' A. Buzzati-Traverso,' CNR, 80131 Naples (Italy); Istituto di diagnosi e cura ' Hermitage Capodimonte,' 80131 Naples (Italy); Colucci-D' Amato, Luca, E-mail: luca.colucci@unina2.it [Institute of Genetics and Biophysics ' A. Buzzati-Traverso,' CNR, 80131 Naples (Italy); Dipartimento di Scienze della Vita, Seconda Universita di Napoli, 81100 Caserta (Italy); Esposito, Maria T., E-mail: maria_teresa.esposito@kcl.ac.uk [CEINGE Biotecnologie Avanzate, 80145 Naples (Italy); Parisi, Silvia, E-mail: parisi@ceinge.unina.it [CEINGE Biotecnologie Avanzate, 80145 Naples (Italy); Stifani, Stefano, E-mail: stefano.stifani@mcgill.ca [Centre for Neuronal Survival, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada H3A 2B4 (Canada); Ramirez, Francesco, E-mail: francesco.ramirez@mssm.edu [Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, NY 10029 (United States); Porzio, Umberto di, E-mail: diporzio@igb.cnr.it [Institute of Genetics and Biophysics ' A. Buzzati-Traverso,' CNR, 80131 Naples (Italy)

    2010-08-15

    Previous gene targeting studies in mice have implicated the nuclear protein Krueppel-like factor 7 (KLF7) in nervous system development while cell culture assays have documented its involvement in cell cycle regulation. By employing short hairpin RNA (shRNA)-mediated gene silencing, here we demonstrate that murine Klf7 gene expression is required for in vitro differentiation of neuroectodermal and mesodermal cells. Specifically, we show a correlation of Klf7 silencing with down-regulation of the neuronal marker microtubule-associated protein 2 (Map2) and the nerve growth factor (NGF) tyrosine kinase receptor A (TrkA) using the PC12 neuronal cell line. Similarly, KLF7 inactivation in Klf7-null mice decreases the expression of the neurogenic marker brain lipid-binding protein/fatty acid-binding protein 7 (BLBP/FABP7) in neural stem cells (NSCs). We also report that Klf7 silencing is detrimental to neuronal and cardiomyocytic differentiation of embryonic stem cells (ESCs), in addition to altering the adipogenic and osteogenic potential of mouse embryonic fibroblasts (MEFs). Finally, our results suggest that genes that are key for self-renewal of undifferentiated ESCs repress Klf7 expression in ESCs. Together with previous findings, these results provide evidence that KLF7 has a broad spectrum of regulatory functions, which reflect the discrete cellular and molecular contexts in which this transcription factor operates.

  20. Dataset of TWIST1-regulated genes in the cranial mesoderm and a transcriptome comparison of cranial mesoderm and cranial neural crest

    Directory of Open Access Journals (Sweden)

    Heidi Bildsoe

    2016-12-01

    Full Text Available This article contains data related to the research article entitled “Transcriptional targets of TWIST1 in the cranial mesoderm regulate cell-matrix interactions and mesenchyme maintenance” by Bildsoe et al. (2016 [1]. The data presented here are derived from: (1 a microarray-based comparison of sorted cranial mesoderm (CM and cranial neural crest (CNC cells from E9.5 mouse embryos; (2 comparisons of transcription profiles of head tissues from mouse embryos with a CM-specific loss-of-function of Twist1 and control mouse embryos collected at E8.5 and E9.5; (3 ChIP-seq using a TWIST1-specific monoclonal antibody with chromatin extracts from TWIST1-expressing MDCK cells, a model for a TWIST1-dependent mesenchymal state.

  1. Multiple mesodermal lineage differentiation of Apodemus sylvaticus embryonic stem cells in vitro

    Directory of Open Access Journals (Sweden)

    Yu Weihua

    2010-06-01

    Full Text Available Abstract Background Embryonic stem (ES cells have attracted significant attention from researchers around the world because of their ability to undergo indefinite self-renewal and produce derivatives from the three cell lineages, which has enormous value in research and clinical applications. Until now, many ES cell lines of different mammals have been established and studied. In addition, recently, AS-ES1 cells derived from Apodemus sylvaticus were established and identified by our laboratory as a new mammalian ES cell line. Hence further research, in the application of AS-ES1 cells, is warranted. Results Herein we report the generation of multiple mesodermal AS-ES1 lineages via embryoid body (EB formation by the hanging drop method and the addition of particular reagents and factors for induction at the stage of EB attachment. The AS-ES1 cells generated separately in vitro included: adipocytes, osteoblasts, chondrocytes and cardiomyocytes. Histochemical staining, immunofluorescent staining and RT-PCR were carried out to confirm the formation of multiple mesodermal lineage cells. Conclusions The appropriate reagents and culture milieu used in mesodermal differentiation of mouse ES cells also guide the differentiation of in vitro AS-ES1 cells into distinct mesoderm-derived cells. This study provides a better understanding of the characteristics of AS-ES1 cells, a new species ES cell line and promotes the use of Apodemus ES cells as a complement to mouse ES cells in future studies.

  2. Changes in glycosaminoglycan structure on differentiation of human embryonic stem cells towards mesoderm and endoderm lineages.

    Science.gov (United States)

    Gasimli, Leyla; Hickey, Anne Marie; Yang, Bo; Li, Guoyun; dela Rosa, Mitche; Nairn, Alison V; Kulik, Michael J; Dordick, Jonathan S; Moremen, Kelley W; Dalton, Stephen; Linhardt, Robert J

    2014-06-01

    Proteoglycans are found on the cell surface and in the extracellular matrix, and serve as prime sites for interaction with signaling molecules. Proteoglycans help regulate pathways that control stem cell fate, and therefore represent an excellent tool to manipulate these pathways. Despite their importance, there is a dearth of data linking glycosaminoglycan structure within proteoglycans with stem cell differentiation. Human embryonic stem cell line WA09 (H9) was differentiated into early mesoderm and endoderm lineages, and the glycosaminoglycanomic changes accompanying these transitions were studied using transcript analysis, immunoblotting, immunofluorescence and disaccharide analysis. Pluripotent H9 cell lumican had no glycosaminoglycan chains whereas in splanchnic mesoderm lumican was glycosaminoglycanated. H9 cells have primarily non-sulfated heparan sulfate chains. On differentiation towards splanchnic mesoderm and hepatic lineages N-sulfo group content increases. Differences in transcript expression of NDST1, HS6ST2 and HS6ST3, three heparan sulfate biosynthetic enzymes, within splanchnic mesoderm cells compared to H9 cells correlate to changes in glycosaminoglycan structure. Differentiation of embryonic stem cells markedly changes the proteoglycanome. The glycosaminoglycan biosynthetic pathway is complex and highly regulated, and therefore, understanding the details of this pathway should enable better control with the aim of directing stem cell differentiation. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. MicroRNAs promote skeletal muscle differentiation of mesodermal iPSC-derived progenitors

    NARCIS (Netherlands)

    Giacomazzi, G. (Giorgia); Holvoet, B. (Bryan); Trenson, S. (Sander); Caluwé, E. (Ellen); Kravic, B. (Bojana); Grosemans, H. (Hanne); Cortés-Calabuig, Á. (Álvaro); Deroose, C.M. (Christophe M.); D. Huylebroeck (Danny); Hashemolhosseini, S. (Said); S. Janssens (Stefan); McNally, E. (Elizabeth); Quattrocelli, M. (Mattia); Sampaolesi, M. (Maurilio)

    2017-01-01

    textabstractMuscular dystrophies (MDs) are often characterized by impairment of both skeletal and cardiac muscle. Regenerative strategies for both compartments therefore constitute a therapeutic avenue. Mesodermal iPSC-derived progenitors (MiPs) can regenerate both striated muscle types

  4. Utx Is Required for Proper Induction of Ectoderm and Mesoderm during Differentiation of Embryonic Stem Cells

    DEFF Research Database (Denmark)

    Morales Torres, Cristina; Laugesen, Anne; Helin, Kristian

    2013-01-01

    to the establishment of ectoderm and mesoderm in vitro. Interestingly, this contribution is independent of the catalytic activity of Utx. Furthermore, we provide data showing that the Utx homologue, Uty, which is devoid of detectable demethylase activity, and Jmjd3 partly compensate for the loss of Utx. Taken together...

  5. A data analysis framework for biomedical big data: Application on mesoderm differentiation of human pluripotent stem cells.

    Science.gov (United States)

    Ulfenborg, Benjamin; Karlsson, Alexander; Riveiro, Maria; Améen, Caroline; Åkesson, Karolina; Andersson, Christian X; Sartipy, Peter; Synnergren, Jane

    2017-01-01

    The development of high-throughput biomolecular technologies has resulted in generation of vast omics data at an unprecedented rate. This is transforming biomedical research into a big data discipline, where the main challenges relate to the analysis and interpretation of data into new biological knowledge. The aim of this study was to develop a framework for biomedical big data analytics, and apply it for analyzing transcriptomics time series data from early differentiation of human pluripotent stem cells towards the mesoderm and cardiac lineages. To this end, transcriptome profiling by microarray was performed on differentiating human pluripotent stem cells sampled at eleven consecutive days. The gene expression data was analyzed using the five-stage analysis framework proposed in this study, including data preparation, exploratory data analysis, confirmatory analysis, biological knowledge discovery, and visualization of the results. Clustering analysis revealed several distinct expression profiles during differentiation. Genes with an early transient response were strongly related to embryonic- and mesendoderm development, for example CER1 and NODAL. Pluripotency genes, such as NANOG and SOX2, exhibited substantial downregulation shortly after onset of differentiation. Rapid induction of genes related to metal ion response, cardiac tissue development, and muscle contraction were observed around day five and six. Several transcription factors were identified as potential regulators of these processes, e.g. POU1F1, TCF4 and TBP for muscle contraction genes. Pathway analysis revealed temporal activity of several signaling pathways, for example the inhibition of WNT signaling on day 2 and its reactivation on day 4. This study provides a comprehensive characterization of biological events and key regulators of the early differentiation of human pluripotent stem cells towards the mesoderm and cardiac lineages. The proposed analysis framework can be used to structure

  6. Linear and quadratic exponential modulation of the solutions of the paraxial wave equation

    International Nuclear Information System (INIS)

    Torre, A

    2010-01-01

    A review of well-known transformations, which allow us to pass from one solution of the paraxial wave equation (PWE) (in one transverse space variable) to another, is presented. Such transformations are framed within the unifying context of the Lie algebra formalism, being related indeed to symmetries of the PWE. Due to the closure property of the symmetry group of the PWE we are led to consider as not trivial only the linear and the quadratic exponential modulation (accordingly, accompanied by a suitable shift or scaling of the space variables) of the original solutions of the PWE, which are seen to be just conveyed by a linear and a quadratic exponential modulation of the relevant 'source' functions. We will see that recently introduced solutions of the 1D PWE in both rectangular and polar coordinates can be deduced from already known solutions through the resulting symmetry transformation related schemes

  7. Description of high-power laser radiation in the paraxial approximation

    Energy Technology Data Exchange (ETDEWEB)

    Milant' ev, V P; Karnilovich, S P; Shaar, Ya N [Peoples' Friendship University of Russia, Moscow (Russian Federation)

    2015-11-30

    We consider the feasibility of an adequate description of a laser pulse of arbitrary shape within the framework of the paraxial approximation. In this approximation, using a parabolic equation and an expansion in the small parameter, expressions are obtained for the field of a sufficiently intense laser radiation given in the form of axially symmetric Hermite – Gaussian beams of arbitrary mode and arbitrary polarisation. It is shown that in the case of sufficiently short pulses, corrections to the transverse components of the laser field are the first-order rather than the secondorder quantities in the expansion in the small parameter. The peculiarities of the description of higher-mode Hermite – Gaussian beams are outlined. (light wave transformation)

  8. Stability of a modified Peaceman–Rachford method for the paraxial Helmholtz equation on adaptive grids

    Energy Technology Data Exchange (ETDEWEB)

    Sheng, Qin, E-mail: Qin_Sheng@baylor.edu [Department of Mathematics and Center for Astrophysics, Space Physics and Engineering Research, Baylor University, One Bear Place, Waco, TX 76798-7328 (United States); Sun, Hai-wei, E-mail: hsun@umac.mo [Department of Mathematics, University of Macau (Macao)

    2016-11-15

    This study concerns the asymptotic stability of an eikonal, or ray, transformation based Peaceman–Rachford splitting method for solving the paraxial Helmholtz equation with high wave numbers. Arbitrary nonuniform grids are considered in transverse and beam propagation directions. The differential equation targeted has been used for modeling propagations of high intensity laser pulses over a long distance without diffractions. Self-focusing of high intensity beams may be balanced with the de-focusing effect of created ionized plasma channel in the situation, and applications of grid adaptations are frequently essential. It is shown rigorously that the fully discretized oscillation-free decomposition method on arbitrary adaptive grids is asymptotically stable with a stability index one. Simulation experiments are carried out to illustrate our concern and conclusions.

  9. Ancient connection between NKL genes and the mesoderm? Insights from Tlx expression in a ctenophore.

    Science.gov (United States)

    Derelle, Romain; Manuel, Michaël

    2007-04-01

    In recent years, evo-devo studies on non-bilaterian metazoans have improved our understanding of the early evolution of animal body plans. In particular, works on cnidarians suggested that contrary to classical views, the mesoderm originated far before the emergence of the Bilateria. In this context, a synthesis of genomic and functional data concerning the Antennapedia (Antp) superclass of homeobox genes suggested that early in animal evolution, each of the three germ layers was under the control of one cluster of Antp genes. In particular, the patterning and differentiation of the mesoderm was under the control of the NKL cluster. The ctenophores stand as a key taxon with respect to such issues because unlike other non-bilaterian phyla, their intermediate germ layer satisfies the strict embryological definition of a mesoderm. For that reason, we investigated the only known member of the NKL group in Ctenophora, a gene previously isolated from Pleurobrachia and attributed to the Tlx family. In our analysis of the NKL group, this ctenophore gene branches as the sister-group of bilaterian Tlx genes, but without statistical support. The expression pattern of this gene was revealed by in situ hybridisation in the adult ctenophore. The expression territories of PpiTlx are predominantly ectodermal, in two distinct types of ciliated epidermal cells and in one category of gland cells. We also identified a probable endodermal site of expression. Because we failed to detect any mesodermal expression, the results do not provide support to the hypothesis of an ancient functional association between the NKL group and the mesoderm.

  10. Two-point paraxial traveltime formula for inhomogeneous isotropic and anisotropic media: Tests of accuracy

    KAUST Repository

    Waheed, Umair bin; Psencik, Ivan; Cerveny, Vlastislav; Iversen, Einar; Alkhalifah, Tariq Ali

    2013-01-01

    On several simple models of isotropic and anisotropic media, we have studied the accuracy of the two-point paraxial traveltime formula designed for the approximate calculation of the traveltime between points S' and R' located in the vicinity of points S and R on a reference ray. The reference ray may be situated in a 3D inhomogeneous isotropic or anisotropic medium with or without smooth curved interfaces. The twopoint paraxial traveltime formula has the form of the Taylor expansion of the two-point traveltime with respect to spatial Cartesian coordinates up to quadratic terms at points S and R on the reference ray. The constant term and the coefficients of the linear and quadratic terms are determined from quantities obtained from ray tracing and linear dynamic ray tracing along the reference ray. The use of linear dynamic ray tracing allows the evaluation of the quadratic terms in arbitrarily inhomogeneous media and, as shown by examples, it extends the region of accurate results around the reference ray between S and R (and even outside this interval) obtained with the linear terms only. Although the formula may be used for very general 3D models, we concentrated on simple 2D models of smoothly inhomogeneous isotropic and anisotropic (~8% and ~20% anisotropy) media only. On tests, in which we estimated twopoint traveltimes between a shifted source and a system of shifted receivers, we found that the formula may yield more accurate results than the numerical solution of an eikonal-based differential equation. The tests also indicated that the accuracy of the formula depends primarily on the length and the curvature of the reference ray and only weakly depends on anisotropy. The greater is the curvature of the reference ray, the narrower its vicinity, in which the formula yields accurate results.

  11. Two-point paraxial traveltime formula for inhomogeneous isotropic and anisotropic media: Tests of accuracy

    KAUST Repository

    Waheed, Umair bin

    2013-09-01

    On several simple models of isotropic and anisotropic media, we have studied the accuracy of the two-point paraxial traveltime formula designed for the approximate calculation of the traveltime between points S\\' and R\\' located in the vicinity of points S and R on a reference ray. The reference ray may be situated in a 3D inhomogeneous isotropic or anisotropic medium with or without smooth curved interfaces. The twopoint paraxial traveltime formula has the form of the Taylor expansion of the two-point traveltime with respect to spatial Cartesian coordinates up to quadratic terms at points S and R on the reference ray. The constant term and the coefficients of the linear and quadratic terms are determined from quantities obtained from ray tracing and linear dynamic ray tracing along the reference ray. The use of linear dynamic ray tracing allows the evaluation of the quadratic terms in arbitrarily inhomogeneous media and, as shown by examples, it extends the region of accurate results around the reference ray between S and R (and even outside this interval) obtained with the linear terms only. Although the formula may be used for very general 3D models, we concentrated on simple 2D models of smoothly inhomogeneous isotropic and anisotropic (~8% and ~20% anisotropy) media only. On tests, in which we estimated twopoint traveltimes between a shifted source and a system of shifted receivers, we found that the formula may yield more accurate results than the numerical solution of an eikonal-based differential equation. The tests also indicated that the accuracy of the formula depends primarily on the length and the curvature of the reference ray and only weakly depends on anisotropy. The greater is the curvature of the reference ray, the narrower its vicinity, in which the formula yields accurate results.

  12. Live imaging-based model selection reveals periodic regulation of the stochastic G1/S phase transition in vertebrate axial development.

    Directory of Open Access Journals (Sweden)

    Mayu Sugiyama

    2014-12-01

    Full Text Available In multicellular organism development, a stochastic cellular response is observed, even when a population of cells is exposed to the same environmental conditions. Retrieving the spatiotemporal regulatory mode hidden in the heterogeneous cellular behavior is a challenging task. The G1/S transition observed in cell cycle progression is a highly stochastic process. By taking advantage of a fluorescence cell cycle indicator, Fucci technology, we aimed to unveil a hidden regulatory mode of cell cycle progression in developing zebrafish. Fluorescence live imaging of Cecyil, a zebrafish line genetically expressing Fucci, demonstrated that newly formed notochordal cells from the posterior tip of the embryonic mesoderm exhibited the red (G1 fluorescence signal in the developing notochord. Prior to their initial vacuolation, these cells showed a fluorescence color switch from red to green, indicating G1/S transitions. This G1/S transition did not occur in a synchronous manner, but rather exhibited a stochastic process, since a mixed population of red and green cells was always inserted between newly formed red (G1 notochordal cells and vacuolating green cells. We termed this mixed population of notochordal cells, the G1/S transition window. We first performed quantitative analyses of live imaging data and a numerical estimation of the probability of the G1/S transition, which demonstrated the existence of a posteriorly traveling regulatory wave of the G1/S transition window. To obtain a better understanding of this regulatory mode, we constructed a mathematical model and performed a model selection by comparing the results obtained from the models with those from the experimental data. Our analyses demonstrated that the stochastic G1/S transition window in the notochord travels posteriorly in a periodic fashion, with doubled the periodicity of the neighboring paraxial mesoderm segmentation. This approach may have implications for the characterization of

  13. Magnifications of Single and Dual Element Accommodative Intraocular Lenses: Paraxial Optics Analysis

    Science.gov (United States)

    Ale, Jit B; Manns, Fabrice; Ho, Arthur

    2010-01-01

    Purpose Using an analytical approach of paraxial optics, we evaluated the magnification of a model eye implanted with single-element (1E) and dual-element (2E) translating-optics accommodative intraocular lenses (AIOL) with an objective of understanding key control parameters relevant to their design. Potential clinical implications of the results arising from pseudophakic accommodation were also considered. Methods Lateral and angular magnifications in a pseudophakic model eye were analyzed using the matrix method of paraxial optics. The effects of key control parameters such as direction (forward or backward) and distance (0 to 2 mm) of translation, power combinations of the 2E-AIOL elements (front element power range +20.0 D to +40.0 D), and amplitudes of accommodation (0 to 4 D) were tested. Relative magnification, defined as the ratio of the retinal image size of the accommodated eye to that of unaccommodated phakic (rLM1) or pseudophakic (rLM2) model eyes, was computed to determine how retinal image size changes with pseudophakic accommodation. Results Both lateral and angular magnifications increased with increased power of the front element in 2E-AIOL and amplitude of accommodation. For a 2E-AIOL with front element power of +35 D, rLM1 and rLM2 increased by 17.0% and 16.3%, respectively, per millimetre of forward translation of the element, compared to the magnification at distance focus (unaccommodated). These changes correspond to a change of 9.4% and 6.5% per dioptre of accommodation, respectively. Angular magnification also increased with pseudophakic accommodation. 1E-AIOLs produced consistently less magnification than 2E-AIOLs. Relative retinal image size decreased at a rate of 0.25% with each dioptre of accommodation in the phakic model eye. The position of the image space nodal point shifted away from the retina (towards the cornea) with both phakic and pseudophakic accommodation. Conclusion Power of the mobile element, and amount and direction of

  14. Near-field multiple traps of paraxial acoustic vortices with strengthened gradient force generated by sector transducer array

    Science.gov (United States)

    Wang, Qingdong; Li, Yuzhi; Ma, Qingyu; Guo, Gepu; Tu, Juan; Zhang, Dong

    2018-01-01

    In order to improve the capability of particle trapping close to the source plane, theoretical and experimental studies on near-field multiple traps of paraxial acoustic vortices (AVs) with a strengthened acoustic gradient force (AGF) generated by a sector transducer array were conducted. By applying the integration of point source radiation, numerical simulations for the acoustic fields generated by the sector transducer array were conducted and compared with those produced by the circular transducer array. It was proved that strengthened AGFs of near-field multiple AVs with higher peak pressures and smaller vortex radii could be produced by the sector transducer array with a small topological charge. The axial distributions of the equivalent potential gradient indicated that the AGFs of paraxial AVs in the near field were much higher than those in the far field, and the distances at the near-field vortex antinodes were also proved to be the ideal trapping positions with relatively higher AGFs. With the established 8-channel AV generation system, theoretical studies were also verified by the experimental measurements of pressure and phase for AVs with various topological charges. The formation of near-field multiple paraxial AVs was verified by the cross-sectional circular pressure distributions with perfect phase spirals around central pressure nulls, and was also proved by the vortex nodes and antinodes along the center axis. The favorable results demonstrated the feasibility of generating near-field multiple traps of paraxial AVs with strengthened AGF using the sector transducer array, and suggested the potential applications of close-range particle trapping in biomedical engineering.

  15. Higher-order paraxial theory of the propagation of ring rippled laser beam in plasma: Relativistic ponderomotive regime

    International Nuclear Information System (INIS)

    Purohit, Gunjan; Rawat, Priyanka; Chauhan, Prashant; Mahmoud, Saleh T.

    2015-01-01

    This article presents higher-order paraxial theory (non-paraxial theory) for the ring ripple formation on an intense Gaussian laser beam and its propagation in plasma, taking into account the relativistic-ponderomotive nonlinearity. The intensity dependent dielectric constant of the plasma has been determined for the main laser beam and ring ripple superimposed on the main laser beam. The dielectric constant of the plasma is modified due to the contribution of the electric field vector of ring ripple. Nonlinear differential equations have been formulated to examine the growth of ring ripple in plasma, self focusing of main laser beam, and ring rippled laser beam in plasma using higher-order paraxial theory. These equations have been solved numerically for different laser intensities and plasma frequencies. The well established experimental laser and plasma parameters are used in numerical calculation. It is observed that the focusing of the laser beams (main and ring rippled) becomes fast in the nonparaxial region by expanding the eikonal and other relevant quantities up to the fourth power of r. The splitted profile of laser beam in the plasma is observed due to uneven focusing/defocusing of the axial and off-axial rays. The growths of ring ripple increase when the laser beam intensity increases. Furthermore, the intensity profile of ring rippled laser beam gets modified due to the contribution of growth rate

  16. Distinct spatiotemporal expression of ISM1 during mouse and chick development.

    Science.gov (United States)

    Osório, Liliana; Wu, Xuewei; Zhou, Zhongjun

    2014-01-01

    Isthmin 1 (ISM1) constitutes the founder of a new family of secreted proteins characterized by the presence of 2 functional domains: thrombospondin type 1 repeat (TSR1) and adhesion-associated domain in MUC4 and other proteins (AMOP). ISM1 was identified in the frog embryo as a member of the FGF8 synexpression group due to its expression in the brain midbrain-hindbrain boundary (MHB) or isthmus. In zebrafish, ISM1 was described as a WNT- and NODAL-regulated gene. The function of ISM1 remains largely elusive. So far, ISM1 has been described as an angiogenesis inhibitor that has a dual function in endothelial cell survival and cell death. For a better understanding of ISM1 function, we examined its spatiotemporal distribution in mouse and chick using RT-PCR, ISH, and IHC analyses. In the mouse, ISM1 transcripts are found in tissues such as the anterior mesendoderm, paraxial and lateral plate mesoderm, MHB and trunk neural tube, as well as in the somites and dermomyotome. In the newborn and adult, ISM1 is prominently expressed in the lung and brain. In addition to its putative role during embryonic and postnatal development, ISM1 may also be important for organ homeostasis in the adult. In the chick embryo, ISM1 transcripts are strongly detected in the ear, eye, and spinal cord primordia. Remarkable differences in ISM1 spatiotemporal expression were found during mouse and chick development, despite the high homology of ISM1 orthologs in these species.

  17. Kinetic features and non-stationary electron trapping in paraxial magnetic nozzles

    Science.gov (United States)

    Sánchez-Arriaga, G.; Zhou, J.; Ahedo, E.; Martínez-Sánchez, M.; Ramos, J. J.

    2018-03-01

    The paraxial expansion of a collisionless plasma jet into vacuum, guided by a magnetic nozzle, is studied with an Eulerian and non-stationary Vlasov-Poisson solver. Parametric analyzes varying the magnetic field expansion rate, the size of the simulation box, and the electrostatic potential fall are presented. After choosing the potential fall leading to a zero net current beam, the steady states of the simulations exhibit a quasi-neutral region followed by a downstream sheath. The latter, an unavoidable consequence of the finite size of the computational domain, does not affect the quasi-neutral region if the box size is chosen appropriately. The steady state presents a strong decay of the perpendicular temperature of the electrons, whose profile versus the inverse of the magnetic field does not depend on the expansion rate within the quasi-neutral region. As a consequence, the electron distribution function is highly anisotropic downstream. The simulations revealed that the ions reach a higher velocity during the transient than in the steady state and their distribution functions are not far from mono-energetic. The density percentage of the population of electrons trapped during the transient, which is computed self-consistently by the code, is up to 25% of the total electron density in the quasi-neutral region. It is demonstrated that the exact amount depends on the history of the system and the steady state is not unique. Nevertheless, the amount of trapped electrons is smaller than the one assumed heuristically by kinetic stationary theories.

  18. Essential and Unexpected Role of YY1 to Promote Mesodermal Cardiac Differentiation

    Science.gov (United States)

    Gregoire, Serge; Karra, Ravi; Passer, Derek; Deutsch, Marcus-Andre; Krane, Markus; Feistritzer, Rebecca; Sturzu, Anthony; Domian, Ibrahim; Saga, Yumiko; Wu, Sean M.

    2013-01-01

    Rational Cardiogenesis is regulated by a complex interplay between transcription factors. However, little is known about how these interactions regulate the transition from mesodermal precursors to cardiac progenitor cells (CPCs). Objective To identify novel regulators of mesodermal cardiac lineage commitment. Methods and Results We performed a bioinformatic-based transcription factor binding site analysis on upstream promoter regions of genes that are enriched in embryonic stem cell (ESC)-derived CPCs. From 32 candidate transcription factors screened, we found that YY1, a repressor of sarcomeric gene expression, is present in CPCs in vivo. Interestingly, we uncovered the ability of YY1 to transcriptionally activate Nkx2.5, a key marker of early cardiogenic commitment. YY1 regulates Nkx2.5 expression via a 2.1 kb cardiac-specific enhancer as demonstrated by in vitro luciferase-based assays and in vivo chromatin immunoprecipitation (ChIP) and genome-wide sequencing analysis. Furthermore, the ability of YY1 to activate Nkx2.5 expression depends on its cooperative interaction with Gata4 at a nearby chromatin. Cardiac mesoderm-specific loss-of-function of YY1 resulted in early embryonic lethality. This was corroborated in vitro by ESC-based assays where we show that the overexpression of YY1 enhanced the cardiogenic differentiation of ESCs into CPCs. Conclusion These results demonstrate an essential and unexpected role for YY1 to promote cardiogenesis as a transcriptional activator of Nkx2.5 and other CPC-enriched genes. PMID:23307821

  19. Expression patterns of Xenopus FGF receptor-like 1/nou-darake in early Xenopus development resemble those of planarian nou-darake and Xenopus FGF8.

    Science.gov (United States)

    Hayashi, Shuichi; Itoh, Mari; Taira, Sumiko; Agata, Kiyokazu; Taira, Masanori

    2004-08-01

    Fibroblast growth factors (FGFs) mediate many cell-to-cell signaling events during early development. Nou-darake (ndk), a gene encoding an FGF receptor (FGFR)-like molecule, was found to be highly and specifically expressed in the head region of the planarian Dugesia japonica, and its functional analyses provided strong molecular evidence for the existence of a brain-inducing circuit based on the FGF signaling pathway. To analyze the role of ndk during vertebrate development, we isolated the Xenopus ortholog of ndk, the vertebrate FGFR-like 1 gene (XFGFRL1). Expression of XFGFRL1/Xndk was first detected in the anterior region at the late gastrula stage and dramatically increased at the early neurula stage in an overall anterior mesendodermal region, including the prechordal plate, paraxial mesoderm, anterior endoderm, and archenteron roof. This anterior expression pattern resembles that of ndk in planarians, suggesting that the expression of FGFRL1/ndk is conserved in evolution between these two distantly diverged organisms. During the tail bud stages, XFGFRL1/Xndk expression was detected in multiple regions, including the forebrain, eyes, midbrain-hindbrain boundary, otic vesicles, visceral arches, and somites. In many of these regions, XFGFRL1/Xndk was coexpressed with XFGF8, indicating that XFGFRL1/Xndk is a member of the XFGF8 synexpression group, which includes sprouty, sef, and isthmin. Copyright 2004 Wiley-Liss, Inc.

  20. Intracellular calcium signal at the leading edge regulates mesodermal sheet migration during Xenopus gastrulation.

    Science.gov (United States)

    Hayashi, Kentaro; Yamamoto, Takamasa S; Ueno, Naoto

    2018-02-05

    During the gastrulation stage in animal embryogenesis, the cells leading the axial mesoderm migrate toward the anterior side of the embryo, vigorously extending cell protrusions such as lamellipodia. It is thought that the leading cells sense gradients of chemoattractants emanating from the ectodermal cells and translate them to initiate and maintain the cell movements necessary for gastrulation. However, it is unclear how the extracellular information is converted to the intracellular chemical reactions that lead to motion. Here we demonstrated that intracellular Ca 2+ levels in the protrusion-forming leading cells are markedly higher than those of the following cells and the axial mesoderm cells. We also showed that inhibiting the intracellular Ca 2+ significantly retarded the gastrulation cell movements, while increasing the intracellular Ca 2+ with an ionophore enhanced the migration. We further found that the ionophore treatment increased the active form of the small GTPase Rac1 in these cells. Our results suggest that transient intracellular Ca 2+ signals play an essential role in the active cell migration during gastrulation.

  1. Loss of Apela Peptide in Mice Causes Low Penetrance Embryonic Lethality and Defects in Early Mesodermal Derivatives

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    Laina Freyer

    2017-08-01

    Full Text Available Apela (also known as Elabela, Ende, and Toddler is a small signaling peptide that activates the G-protein-coupled receptor Aplnr to stimulate cell migration during zebrafish gastrulation. Here, using CRISPR/Cas9 to generate a null, reporter-expressing allele, we study the role of Apela in the developing mouse embryo. We found that loss of Apela results in low-penetrance cardiovascular defects that manifest after the onset of circulation. Three-dimensional micro-computed tomography revealed a higher penetrance of vascular remodeling defects, from which some mutants recover, and identified extraembryonic anomalies as the earliest morphological distinction in Apela mutant embryos. Transcriptomics at late gastrulation identified aberrant upregulation of erythroid and myeloid markers in mutant embryos prior to the appearance of physical malformations. Double-mutant analyses showed that loss of Apela signaling impacts early Aplnr-expressing mesodermal populations independently of the alternative ligand Apelin, leading to lethal cardiac defects in some Apela null embryos.

  2. TORBEAM 2.0, a paraxial beam tracing code for electron-cyclotron beams in fusion plasmas for extended physics applications

    Science.gov (United States)

    Poli, E.; Bock, A.; Lochbrunner, M.; Maj, O.; Reich, M.; Snicker, A.; Stegmeir, A.; Volpe, F.; Bertelli, N.; Bilato, R.; Conway, G. D.; Farina, D.; Felici, F.; Figini, L.; Fischer, R.; Galperti, C.; Happel, T.; Lin-Liu, Y. R.; Marushchenko, N. B.; Mszanowski, U.; Poli, F. M.; Stober, J.; Westerhof, E.; Zille, R.; Peeters, A. G.; Pereverzev, G. V.

    2018-04-01

    The paraxial WKB code TORBEAM (Poli, 2001) is widely used for the description of electron-cyclotron waves in fusion plasmas, retaining diffraction effects through the solution of a set of ordinary differential equations. With respect to its original form, the code has undergone significant transformations and extensions, in terms of both the physical model and the spectrum of applications. The code has been rewritten in Fortran 90 and transformed into a library, which can be called from within different (not necessarily Fortran-based) workflows. The models for both absorption and current drive have been extended, including e.g. fully-relativistic calculation of the absorption coefficient, momentum conservation in electron-electron collisions and the contribution of more than one harmonic to current drive. The code can be run also for reflectometry applications, with relativistic corrections for the electron mass. Formulas that provide the coupling between the reflected beam and the receiver have been developed. Accelerated versions of the code are available, with the reduced physics goal of inferring the location of maximum absorption (including or not the total driven current) for a given setting of the launcher mirrors. Optionally, plasma volumes within given flux surfaces and corresponding values of minimum and maximum magnetic field can be provided externally to speed up the calculation of full driven-current profiles. These can be employed in real-time control algorithms or for fast data analysis.

  3. Negative optical spin torque wrench of a non-diffracting non-paraxial fractional Bessel vortex beam

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    Mitri, F. G.

    2016-10-01

    An absorptive Rayleigh dielectric sphere in a non-diffracting non-paraxial fractional Bessel vortex beam experiences a spin torque. The axial and transverse radiation spin torque components are evaluated in the dipole approximation using the radiative correction of the electric field. Particular emphasis is given on the polarization as well as changing the topological charge α and the half-cone angle of the beam. When α is zero, the axial spin torque component vanishes. However, when α becomes a real positive number, the vortex beam induces left-handed (negative) axial spin torque as the sphere shifts off-axially from the center of the beam. The results show that a non-diffracting non-paraxial fractional Bessel vortex beam is capable of inducing a spin reversal of an absorptive Rayleigh sphere placed arbitrarily in its path. Potential applications are yet to be explored in particle manipulation, rotation in optical tweezers, optical tractor beams, and the design of optically-engineered metamaterials to name a few areas.

  4. Negative optical spin torque wrench of a non-diffracting non-paraxial fractional Bessel vortex beam

    International Nuclear Information System (INIS)

    Mitri, F.G.

    2016-01-01

    An absorptive Rayleigh dielectric sphere in a non-diffracting non-paraxial fractional Bessel vortex beam experiences a spin torque. The axial and transverse radiation spin torque components are evaluated in the dipole approximation using the radiative correction of the electric field. Particular emphasis is given on the polarization as well as changing the topological charge α and the half-cone angle of the beam. When α is zero, the axial spin torque component vanishes. However, when α becomes a real positive number, the vortex beam induces left-handed (negative) axial spin torque as the sphere shifts off-axially from the center of the beam. The results show that a non-diffracting non-paraxial fractional Bessel vortex beam is capable of inducing a spin reversal of an absorptive Rayleigh sphere placed arbitrarily in its path. Potential applications are yet to be explored in particle manipulation, rotation in optical tweezers, optical tractor beams, and the design of optically-engineered metamaterials to name a few areas. - Highlights: • Optical nondiffracting nonparaxial fractional Bessel vortex beam is considered. • Negative spin torque on an absorptive dielectric Rayleigh sphere is predicted numerically. • Negative spin torque occurs as the sphere departs from the center of the beam.

  5. Primary Bovine Extra-Embryonic Cultured Cells: A New Resource for the Study of In Vivo Peri-Implanting Phenotypes and Mesoderm Formation.

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    Isabelle Hue

    Full Text Available In addition to nourishing the embryo, extra-embryonic tissues (EETs contribute to early embryonic patterning, primitive hematopoiesis, and fetal health. These tissues are of major importance for human medicine, as well as for efforts to improve livestock efficiency, but they remain incompletely understood. In bovines, EETs are accessible easily, in large amounts, and prior to implantation. We took advantage of this system to describe, in vitro and in vivo, the cell types present in bovine EETs at Day 18 of development. Specifically, we characterized the gene expression patterns and phenotypes of bovine extra-embryonic ectoderm (or trophoblast; bTC, endoderm (bXEC, and mesoderm (bXMC cells in culture and compared them to their respective in vivo micro-dissected cells. After a week of culture, certain characteristics (e.g., gene expression of the in vitro cells were altered with respect to the in vivo cells, but we were able to identify "cores" of cell-type-specific (and substrate-independent genes that were shared between in vitro and in vivo samples. In addition, many cellular phenotypes were cell-type-specific with regard to extracellular adhesion. We evaluated the ability of individual bXMCs to migrate and spread on micro-patterns, and observed that they easily adapted to diverse environments, similar to in vivo EE mesoderm cells, which encounter different EE epithelia to form chorion, yolk sac, and allantois. With these tissue interactions, different functions arose that were detected in silico and corroborated in vivo at D21-D25. Moreover, analysis of bXMCs allowed us to identify the EE cell ring surrounding the embryonic disc (ED at D14-15 as mesoderm cells, which had been hypothesized but not shown prior to this study. We envision these data will serve as a major resource for the future in the analysis of peri-implanting phenotypes in response to the maternal metabolism and contribute to subsequent studies of placental/fetal development in

  6. Xmsx-1 modifies mesodermal tissue pattern along dorsoventral axis in Xenopus laevis embryo.

    Science.gov (United States)

    Maeda, R; Kobayashi, A; Sekine, R; Lin, J J; Kung, H; Maéno, M

    1997-07-01

    This study analyzes the expression and the function of Xenopus msx-1 (Xmsx-1) in embryos, in relation to the ventralizing activity of bone morphogenetic protein-4 (BMP-4). Expression of Xmsx-1 was increased in UV-treated ventralized embryos and decreased in LiCl-treated dorsalized embryos at the neurula stage (stage 14). Whole-mount in situ hybridization analysis showed that Xmsx-1 is expressed in marginal zone and animal pole areas, laterally and ventrally, but not dorsally, at mid-gastrula (stage 11) and late-gastrula (stage 13) stages. Injection of BMP-4 RNA, but not activin RNA, induced Xmsx-1 expression in the dorsal marginal zone at the early gastrula stage (stage 10+), and introduction of a dominant negative form of BMP-4 receptor RNA suppressed Xmsx-1 expression in animal cap and ventral marginal zone explants at stage 14. Thus, Xmsx-1 is a target gene specifically regulated by BMP-4 signaling. Embryos injected with Xmsx-1 RNA in dorsal blastomeres at the 4-cell stage exhibited a ventralized phenotype, with microcephaly and swollen abdomen. Histological observation and immunostaining revealed that these embryos had a large block of muscle tissue in the dorsal mesodermal area instead of notochord. On the basis of molecular marker analysis, however, the injection of Xmsx-1 RNA did not induce the expression of alpha-globin, nor reduce cardiac alpha-actin in dorsal marginal zone explants. Furthermore, a significant amount of alpha-actin was induced and alpha-globin was turned off in the ventral marginal zone explants injected with Xmsx-1. These results indicated that Xmsx-1 is a target gene of BMP-4 signaling, but possesses a distinct activity on dorsal-ventral patterning of mesodermal tissues.

  7. FZD4 Marks Lateral Plate Mesoderm and Signals with NORRIN to Increase Cardiomyocyte Induction from Pluripotent Stem Cell-Derived Cardiac Progenitors

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    Charles Yoon

    2018-01-01

    Full Text Available The identification of cell surface proteins on stem cells or stem cell derivatives is a key strategy for the functional characterization, isolation, and understanding of stem cell population dynamics. Here, using an integrated mass spectrometry- and microarray-based approach, we analyzed the surface proteome and transcriptome of cardiac progenitor cells (CPCs generated from the stage-specific differentiation of mouse and human pluripotent stem cells. Through bioinformatics analysis, we have identified and characterized FZD4 as a marker for lateral plate mesoderm. Additionally, we utilized FZD4, in conjunction with FLK1 and PDGFRA, to further purify CPCs and increase cardiomyocyte (CM enrichment in both mouse and human systems. Moreover, we have shown that NORRIN presented to FZD4 further increases CM output via proliferation through the canonical WNT pathway. Taken together, these findings demonstrate a role for FZD4 in mammalian cardiac development.

  8. Time-dependent patterning of the mesoderm and endoderm by Nodal signals in zebrafish

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    Dougan Scott T

    2007-03-01

    Full Text Available Abstract Background The vertebrate body plan is generated during gastrulation with the formation of the three germ layers. Members of the Nodal-related subclass of the TGF-β superfamily induce and pattern the mesoderm and endoderm in all vertebrates. In zebrafish, two nodal-related genes, called squint and cyclops, are required in a dosage-dependent manner for the formation of all derivatives of the mesoderm and endoderm. These genes are expressed dynamically during the blastula stages and may have different roles at different times. This question has been difficult to address because conditions that alter the timing of nodal-related gene expression also change Nodal levels. We utilized a pharmacological approach to conditionally inactivate the ALK 4, 5 and 7 receptors during the blastula stages without disturbing earlier signaling activity. This permitted us to directly examine when Nodal signals specify cell types independently of dosage effects. Results We show that two drugs, SB-431542 and SB-505124, completely block the response to Nodal signals when added to embryos after the mid-blastula transition. By blocking Nodal receptor activity at later stages, we demonstrate that Nodal signaling is required from the mid-to-late blastula period to specify sequentially, the somites, notochord, blood, Kupffer's vesicle, hatching gland, heart, and endoderm. Blocking Nodal signaling at late times prevents specification of cell types derived from the embryo margin, but not those from more animal regions. This suggests a linkage between cell fate and length of exposure to Nodal signals. Confirming this, cells exposed to a uniform Nodal dose adopt progressively more marginal fates with increasing lengths of exposure. Finally, cell fate specification is delayed in squint mutants and accelerated when Nodal levels are elevated. Conclusion We conclude that (1 Nodal signals are most active during the mid-to-late blastula stages, when nodal-related gene

  9. Constitutive expression of pluripotency-associated genes in mesodermal progenitor cells (MPCs.

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    Simone Pacini

    Full Text Available BACKGROUND: We recently characterized a progenitor of mesodermal lineage (MPCs from the human bone marrow of adults or umbilical cord blood. These cells are progenitors able to differentiate toward mesenchymal, endothelial and cardiomyogenic lineages. Here we present an extensive molecular characterization of MPCs, from bone marrow samples, including 39 genes involved in stem cell machinery, differentiation and cell cycle regulation. METHODOLOGY/PRINCIPAL FINDINGS: MPCs are cytofluorimetrically characterized and quantitative RT-PCR was performed to evaluate the gene expression profile, comparing it with MSCs and hESCs lines. Immunofluorescence and dot-blot analysis confirm qRT-PCR data. MPCs exhibit an increased expression of OCT4, NANOG, SALL4, FBX15, SPP1 and to a lesser extent c-MYC and KLF4, but lack LIN28 and SOX2. MPCs highly express SOX15. CONCLUSIONS/SIGNIFICANCE: MPCs express many pluripotency-associated genes and show a peculiar Oct-4 molecular circuit. Understanding this unique molecular mechanism could lead to identifying MPCs as feasible, long telomeres, target cells for reprogramming with no up-regulation of the p53 pathway. Furthermore MPCs are easily and inexpensively harvested from human bone marrow.

  10. Circulation-Independent Differentiation Pathway from Extraembryonic Mesoderm toward Hematopoietic Stem Cells via Hemogenic Angioblasts

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    Yosuke Tanaka

    2014-07-01

    Full Text Available A large gap exists in our understanding of the course of differentiation from mesoderm to definitive hematopoietic stem cells (HSCs. Previously, we reported that Runx1+ cells in embryonic day 7.5 (E7.5 embryos contribute to the hemogenic endothelium in the E10.5 aorta-gonad-mesonephros (AGM region and HSCs in the adult bone marrow. Here, we show that two Runx1+ populations subdivided by Gata1 expression exist in E7.5 embryos. The hemogenic endothelium and the HSCs are derived only from the Runx1+Gata1− population. A subset of this population moves from the extra- to intraembryonic region during E7.5–E8.0, where it contributes to the hemogenic endothelium of the dorsal aorta (DA. Migration occurs before the heartbeat is initiated, and it is independent of circulation. This suggests a developmental trajectory from Runx1+ cells in the E7.5 extraembryonic region to definitive HSCs via the hemogenic endothelium.

  11. Advanced Mesodermal (Müllerian Adenosarcoma of the Ovary: Metastases to the Lungs, Mouth, and Brain

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    A. Daskalaki

    2015-01-01

    Full Text Available Background. A malignant mixed Müllerian tumor (MMMT is a malignant neoplasm found in the uterus, the ovaries, the fallopian tubes, and other parts of the body that contains both carcinomatous (epithelial tissue and sarcomatous (connective tissue components. Outcome of MMMTs is determined primarily by depth of invasion and stage. The metastatic background of these lesions is controversial and unknown. Case Report. A 75-year-old woman was admitted to the hospital with anorexia, weakness, and persistent coughing. The imaging exams revealed a solid, promiscuous lesion of 16 × 14 cm in dimensions located into the small pelvis, surrounding the uterus and the ovaries. The patient underwent exploratory laparotomy. The mass was removed and the histological examination of the specimen revealed an advanced mesodermal adenocarcinoma of the ovary (MMMT. Nine days after the operation the patient presented with metastatic lesions in the mouth as well as the lungs. Within a month after the discharge from the hospital metastatic lesions of the MMMT were also depicted in the CT brain scan. Conclusion. Despite the fact that sarcomas have a long-term metastatic potential, to our knowledge this is the first case of Müllerian adenosarcoma presenting with such extraperitoneal metastases.

  12. tortuga refines Notch pathway gene expression in the zebrafish presomitic mesoderm at the post-transcriptional level.

    Science.gov (United States)

    Dill, Kariena K; Amacher, Sharon L

    2005-11-15

    We have identified the zebrafish tortuga (tor) gene by an ENU-induced mutation that disrupts the presomitic mesoderm (PSM) expression of Notch pathway genes. In tor mutants, Notch pathway gene expression persists in regions of the PSM where expression is normally off in wild type embryos. The expression of hairy/Enhancer of split-related 1 (her1) is affected first, followed by the delta genes deltaC and deltaD, and finally, by another hairy/Enhancer of split-related gene, her7. In situ hybridization with intron-specific probes for her1 and deltaC indicates that transcriptional bursts of expression are normal in tor mutants, suggesting that tor normally functions to refine her1 and deltaC message levels downstream of transcription. Despite the striking defects in Notch pathway gene expression, somite boundaries form normally in tor mutant embryos, although somitic mesoderm defects are apparent later, when cells mature to form muscle fibers. Thus, while the function of Notch pathway genes is required for proper somite formation, the tor mutant phenotype suggests that precise oscillations of Notch pathway transcripts are not essential for establishing segmental pattern in the presomitic mesoderm.

  13. Behavior of conducting solid or liquid jet moving in magnetic field: (1) paraxial; (2) transverse; (3) oblique

    International Nuclear Information System (INIS)

    Weggel, R.J.

    1998-06-01

    When a conductor moves through a nonuniform magnetic field, eddy currents flow that interact with the field to decelerate the conductor and perhaps change its trajectory, orientation and, if a liquid, shape. A rod of radius a 1 cm and the density and electrical conductivity of melted gallium (γ 6.1 g/cm 3 , ρ = 26 microΩ cm) will decelerate 6.3 m/s in a 0.5 m ramp of paraxial field with a constant gradient g of 40 T/m (ΔB = 20 T). The deceleration is proportional to a 2 gΔB/γρ, independent of the velocity. The bar decelerates about twice as much in a 20 T, 0.5 m ramp of transverse field. A bar traveling at a shallow angle to such a field decelerates about 6.3 m/s. If the bar is 0.25 m long and moves at 20 m/s, it aligns with the field in ∼10 ms, during which time it advances ∼0.2 m

  14. Paraxial propagation dynamics of the radially polarized Airy beams in uniaxial crystals orthogonal to the optical axis.

    Science.gov (United States)

    Xie, Jintao; Zhang, Jianbin; Zheng, Xitao; Ye, Junran; Deng, Dongmei

    2018-04-30

    We study the paraxial propagation of the radially polarized Airy beams (RPAiBs) in uniaxial crystals orthogonal to the optical axis analytically and numerically. The propagation trajectory, the intensity and the radiation forces of the RPAiBs are investigated and the properties are elucidated by numerical examples in this paper. Results show that the RPAiBs evolve into the beams produced by the x-direction electric field (RPAiXBs) and the y-direction electric field (PRAiYBs) which are totally different in uniaxial crystals. During the propagation, the intensity of the RPAiXBs transfers from the side lobe in the x-direction to the main lobe and finally returns to the side lobe in the x-direction again, but that of the RPAiYBs transfers from the side lobe in the y-direction to the main lobe and flows to the side lobe in the x-direction at last. The effect of the intensity focusing for the RPAiXBs can be modulated by the ratio of the extraordinary index (ne) to the ordinary index (no) in anisotropic medium, which contributes to the intensity focusing of the RPAiBs in a short distance a lot. We can adjust the intensity distribution especially the focusing position, the propagation trajectory and the radiation forces distributions of the RPAiXBs through choosing an appropriate value of the ratio of ne to no to meet the actual usage accordingly.

  15. Paraxial light distribution in the focal region of a lens: a comparison of several analytical solutions and a numerical result

    Science.gov (United States)

    Wu, Yang; Kelly, Damien P.

    2014-12-01

    The distribution of the complex field in the focal region of a lens is a classical optical diffraction problem. Today, it remains of significant theoretical importance for understanding the properties of imaging systems. In the paraxial regime, it is possible to find analytical solutions in the neighborhood of the focus, when a plane wave is incident on a focusing lens whose finite extent is limited by a circular aperture. For example, in Born and Wolf's treatment of this problem, two different, but mathematically equivalent analytical solutions, are presented that describe the 3D field distribution using infinite sums of ? and ? type Lommel functions. An alternative solution expresses the distribution in terms of Zernike polynomials, and was presented by Nijboer in 1947. More recently, Cao derived an alternative analytical solution by expanding the Fresnel kernel using a Taylor series expansion. In practical calculations, however, only a finite number of terms from these infinite series expansions is actually used to calculate the distribution in the focal region. In this manuscript, we compare and contrast each of these different solutions to a numerically calculated result, paying particular attention to how quickly each solution converges for a range of different spatial locations behind the focusing lens. We also examine the time taken to calculate each of the analytical solutions. The numerical solution is calculated in a polar coordinate system and is semi-analytic. The integration over the angle is solved analytically, while the radial coordinate is sampled with a sampling interval of ? and then numerically integrated. This produces an infinite set of replicas in the diffraction plane, that are located in circular rings centered at the optical axis and each with radii given by ?, where ? is the replica order. These circular replicas are shown to be fundamentally different from the replicas that arise in a Cartesian coordinate system.

  16. Paraxial light distribution in the focal region of a lens: a comparison of several analytical solutions and a numerical result.

    Science.gov (United States)

    Wu, Yang; Kelly, Damien P

    2014-12-12

    The distribution of the complex field in the focal region of a lens is a classical optical diffraction problem. Today, it remains of significant theoretical importance for understanding the properties of imaging systems. In the paraxial regime, it is possible to find analytical solutions in the neighborhood of the focus, when a plane wave is incident on a focusing lens whose finite extent is limited by a circular aperture. For example, in Born and Wolf's treatment of this problem, two different, but mathematically equivalent analytical solutions, are presented that describe the 3D field distribution using infinite sums of [Formula: see text] and [Formula: see text] type Lommel functions. An alternative solution expresses the distribution in terms of Zernike polynomials, and was presented by Nijboer in 1947. More recently, Cao derived an alternative analytical solution by expanding the Fresnel kernel using a Taylor series expansion. In practical calculations, however, only a finite number of terms from these infinite series expansions is actually used to calculate the distribution in the focal region. In this manuscript, we compare and contrast each of these different solutions to a numerically calculated result, paying particular attention to how quickly each solution converges for a range of different spatial locations behind the focusing lens. We also examine the time taken to calculate each of the analytical solutions. The numerical solution is calculated in a polar coordinate system and is semi-analytic. The integration over the angle is solved analytically, while the radial coordinate is sampled with a sampling interval of [Formula: see text] and then numerically integrated. This produces an infinite set of replicas in the diffraction plane, that are located in circular rings centered at the optical axis and each with radii given by [Formula: see text], where [Formula: see text] is the replica order. These circular replicas are shown to be fundamentally

  17. Hidden in the crowd: primordial germ cells and somatic stem cells in the mesodermal posterior growth zone of the polychaete Platynereis dumerillii are two distinct cell populations

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    Rebscher Nicole

    2012-04-01

    Full Text Available Abstract Background In the polychaete Platynereis, the primordial germ cells (PGCs emerge from the vasa, piwi, and PL10 expressing mesodermal posterior growth zone (MPGZ at the end of larval development, suggesting a post-embryonic formation from stem cells. Methods In order to verify this hypothesis, embryos and larvae were pulse labeled with the proliferation marker 5-ethynyl-2'-deoxyuridine (EdU at different stages of development. Subsequently, the PGCs were visualized in 7-day-old young worms using antibodies against the Vasa protein. Results Surprisingly, the primordial germ cells of Platynereis incorporate EdU only shortly before gastrulation (6-8 hours post fertilization (hpf, which coincides with the emergence of four small blastomeres from the mesoblast lineage. We conclude that these so-called 'secondary mesoblast cells' constitute the definitive PGCs in Platynereis. In contrast, the cells of the MPGZ incorporate EdU only from the pre-trochophore stage onward (14 hpf. Conclusion While PGCs and the cells of the MPGZ in Platynereis are indistinguishable in morphology and both express the germline markers vasa, nanos, and piwi, a distinct cluster of PGCs is detectable anterior of the MPGZ following EdU pulse-labeling. Indeed the PGCs form independently from the stem cells of the MPGZ prior to gastrulation. Our data suggest an early PGC formation in the polychaete by preformation rather than by epigenesis.

  18. The mouse Gtl2 gene is differentially expressed during embryonic development, encodes multiple alternatively spliced transcripts, and may act as an RNA.

    Science.gov (United States)

    Schuster-Gossler, K; Bilinski, P; Sado, T; Ferguson-Smith, A; Gossler, A

    1998-06-01

    We have isolated a novel mouse gene (Gtl2) from the site of a gene trap integration (Gtl2lacZ) that gave rise to developmentally regulated lacZ expression, and a dominant parental-origin-dependent phenotype. Heterozygous Gtl2lacZ mice that inherited the transgene from the father showed a proportionate dwarfism phenotype, whereas the penetrance and expressivity of the phenotype was strongly reduced in Gtl2lacZ mice that inherited the transgene from the mother. Gtl2 expression is highly similar to the beta-galactosidase staining pattern, and is down-regulated but not abolished in mice carrying the Gtl2lacZ insertion. In early postimplantation embryos, Gtl2 is expressed in the visceral yolk sac and embryonic ectoderm. During subsequent development and organogenesis, Gtl2 transcripts are abundant in the paraxial mesoderm closely correlated with myogenic differentiation, in parts of the central nervous system, and in the epithelial ducts of developing excretory organs. The Gtl2 gene gives rise to various differentially spliced transcripts, which contain multiple small open reading frames (ORF). However, none of the ATG codons of these ORFs is in the context of a strong Kozak consensus sequence for initiation of translation, suggesting that Gtl2 might function as an RNA. Nuclear Gtl2 RNA was detected in a temporally and spatially regulated manner, and partially processed Gtl2 transcripts were readily detected in Northern blot hybridizations of polyadenylated RNA, suggesting that primary Gtl2 transcripts are differently processed in various cell types during development. Gtl2 transcript levels are present in parthenogenic embryos but may be reduced, consistent with the pattern of inheritance of the Gtl2lacZ phenotype.

  19. The C. elegans SoxC protein SEM-2 opposes differentiation factors to promote a proliferative blast cell fate in the postembryonic mesoderm

    Science.gov (United States)

    Tian, Chenxi; Shi, Herong; Colledge, Clark; Stern, Michael; Waterston, Robert; Liu, Jun

    2011-01-01

    The proper development of multicellular organisms requires precise regulation and coordination of cell fate specification, cell proliferation and differentiation. Abnormal regulation and coordination of these processes could lead to disease, including cancer. We have examined the function of the sole C. elegans SoxC protein, SEM-2, in the M lineage, which produces the postembryonic mesoderm. We found that SEM-2/SoxC is both necessary and sufficient to promote a proliferating blast cell fate, the sex myoblast fate, over a differentiated striated bodywall muscle fate. A number of factors control the specific expression of sem-2 in the sex myoblast precursors and their descendants. This includes direct control of sem-2 expression by a Hox-PBC complex. The crucial nature of the HOX/PBC factors in directly enhancing expression of this proliferative factor in the C. elegans M lineage suggests a possible more general link between Hox-PBC factors and SoxC proteins in regulating cell proliferation. PMID:21307099

  20. Effect of angiotensin II on proliferation and differentiation of mouse induced pluripotent stem cells into mesodermal progenitor cells

    Energy Technology Data Exchange (ETDEWEB)

    Ishizuka, Toshiaki, E-mail: tishizu@ndmc.ac.jp [Department of Pharmacology, National Defense Medical College, Tokorozawa, Saitama 359-8513 (Japan); Goshima, Hazuki; Ozawa, Ayako; Watanabe, Yasuhiro [Department of Pharmacology, National Defense Medical College, Tokorozawa, Saitama 359-8513 (Japan)

    2012-03-30

    Highlights: Black-Right-Pointing-Pointer Treatment with angiotensin II enhanced LIF-induced DNA synthesis of mouse iPS cells. Black-Right-Pointing-Pointer Angiotensin II may enhance the DNA synthesis via induction of superoxide. Black-Right-Pointing-Pointer Treatment with angiotensin II significantly increased JAK/STAT3 phosphorylation. Black-Right-Pointing-Pointer Angiotensin II enhanced differentiation into mesodermal progenitor cells. Black-Right-Pointing-Pointer Angiotensin II may enhance the differentiation via activation of p38 MAPK. -- Abstract: Previous studies suggest that angiotensin receptor stimulation may enhance not only proliferation but also differentiation of undifferentiated stem/progenitor cells. Therefore, in the present study, we determined the involvement of the angiotensin receptor in the proliferation and differentiation of mouse induced pluripotent stem (iPS) cells. Stimulation with angiotensin II (Ang II) significantly increased DNA synthesis in mouse iPS cells cultured in a medium with leukemia inhibitory factor (LIF). Pretreatment of the cells with either candesartan (a selective Ang II type 1 receptor [AT{sub 1}R] antagonist) or Tempol (a cell-permeable superoxide scavenger) significantly inhibited Ang II-induced DNA synthesis. Treatment with Ang II significantly increased JAK/STAT3 phosphorylation. Pretreatment with candesartan significantly inhibited Ang II- induced JAK/STAT3 phosphorylation. In contrast, induction of mouse iPS cell differentiation into Flk-1-positive mesodermal progenitor cells was performed in type IV collagen (Col IV)- coated dishes in a differentiation medium without LIF. When Col IV-exposed iPS cells were treated with Ang II for 5 days, the expression of Flk-1 was significantly increased compared with that in the cells treated with the vehicle alone. Pretreatment of the cells with both candesartan and SB203580 (a p38 MAPK inhibitor) significantly inhibited the Ang II- induced increase in Flk-1 expression

  1. Effect of angiotensin II on proliferation and differentiation of mouse induced pluripotent stem cells into mesodermal progenitor cells

    International Nuclear Information System (INIS)

    Ishizuka, Toshiaki; Goshima, Hazuki; Ozawa, Ayako; Watanabe, Yasuhiro

    2012-01-01

    Highlights: ► Treatment with angiotensin II enhanced LIF-induced DNA synthesis of mouse iPS cells. ► Angiotensin II may enhance the DNA synthesis via induction of superoxide. ► Treatment with angiotensin II significantly increased JAK/STAT3 phosphorylation. ► Angiotensin II enhanced differentiation into mesodermal progenitor cells. ► Angiotensin II may enhance the differentiation via activation of p38 MAPK. -- Abstract: Previous studies suggest that angiotensin receptor stimulation may enhance not only proliferation but also differentiation of undifferentiated stem/progenitor cells. Therefore, in the present study, we determined the involvement of the angiotensin receptor in the proliferation and differentiation of mouse induced pluripotent stem (iPS) cells. Stimulation with angiotensin II (Ang II) significantly increased DNA synthesis in mouse iPS cells cultured in a medium with leukemia inhibitory factor (LIF). Pretreatment of the cells with either candesartan (a selective Ang II type 1 receptor [AT 1 R] antagonist) or Tempol (a cell-permeable superoxide scavenger) significantly inhibited Ang II-induced DNA synthesis. Treatment with Ang II significantly increased JAK/STAT3 phosphorylation. Pretreatment with candesartan significantly inhibited Ang II- induced JAK/STAT3 phosphorylation. In contrast, induction of mouse iPS cell differentiation into Flk-1-positive mesodermal progenitor cells was performed in type IV collagen (Col IV)- coated dishes in a differentiation medium without LIF. When Col IV-exposed iPS cells were treated with Ang II for 5 days, the expression of Flk-1 was significantly increased compared with that in the cells treated with the vehicle alone. Pretreatment of the cells with both candesartan and SB203580 (a p38 MAPK inhibitor) significantly inhibited the Ang II- induced increase in Flk-1 expression. Treatment with Ang II enhanced the phosphorylation of p38 MAPK in Col IV- exposed iPS cells. These results suggest that the stimulation

  2. Non-paraxial approach

    Indian Academy of Sciences (India)

    region, some alternative methods for self-focusing and self-trapping of beam in plasma had .... For high intensity beam, ε2. εS. |E|2 ^ ..... non-linear dielectric inhomogeneity perceived by the wave cannot be ... The authors are thankful to the Principal, Government College, Ajmer for ... providing Teacher Research Fellowship.

  3. Tbx1 is required autonomously for cell survival and fate in the pharyngeal core mesoderm to form the muscles of mastication

    Science.gov (United States)

    Kong, Ping; Racedo, Silvia E.; Macchiarulo, Stephania; Hu, Zunju; Carpenter, Courtney; Guo, Tingwei; Wang, Tao; Zheng, Deyou; Morrow, Bernice E.

    2014-01-01

    Velo-cardio-facial/DiGeorge syndrome, also known as 22q11.2 deletion syndrome, is a congenital anomaly disorder characterized by craniofacial anomalies including velo-pharyngeal insufficiency, facial muscle hypotonia and feeding difficulties, in part due to hypoplasia of the branchiomeric muscles. Inactivation of both alleles of mouse Tbx1, encoding a T-box transcription factor, deleted on chromosome 22q11.2, results in reduction or loss of branchiomeric muscles. To identify downstream pathways, we performed gene profiling of microdissected pharyngeal arch one (PA1) from Tbx1+/+ and Tbx1−/− embryos at stages E9.5 (somites 20–25) and E10.5 (somites 30–35). Basic helix–loop–helix (bHLH) transcription factors were reduced, while secondary heart field genes were increased in expression early and were replaced by an increase in expression of cellular stress response genes later, suggesting a change in gene expression patterns or cell populations. Lineage tracing studies using Mesp1Cre and T-Cre drivers showed that core mesoderm cells within PA1 were present at E9.5 but were greatly reduced by E10.5 in Tbx1−/− embryos. Using Tbx1Cre knock-in mice, we found that cells are lost due to apoptosis, consistent with increase in expression of cellular stress response genes at E10.5. To determine whether Tbx1 is required autonomously in the core mesoderm, we used Mesp1Cre and T-Cre mesodermal drivers in combination with inactivate Tbx1 and found reduction or loss of branchiomeric muscles from PA1. These mechanistic studies inform us that Tbx1 is required upstream of key myogenic genes needed for core mesoderm cell survival and fate, between E9.5 and E10.5, resulting in formation of the branchiomeric muscles. PMID:24705356

  4. Functional importance of evolutionally conserved Tbx6 binding sites in the presomitic mesoderm-specific enhancer of Mesp2.

    Science.gov (United States)

    Yasuhiko, Yukuto; Kitajima, Satoshi; Takahashi, Yu; Oginuma, Masayuki; Kagiwada, Harumi; Kanno, Jun; Saga, Yumiko

    2008-11-01

    The T-box transcription factor Tbx6 controls the expression of Mesp2, which encodes a basic helix-loop-helix transcription factor that has crucial roles in somitogenesis. In cultured cells, Tbx6 binding to the Mesp2 enhancer region is essential for the activation of Mesp2 by Notch signaling. However, it is not known whether this binding is required in vivo. Here we report that an Mesp2 enhancer knockout mouse bearing mutations in two crucial Tbx6 binding sites does not express Mesp2 in the presomitic mesoderm. This absence leads to impaired skeletal segmentation identical to that reported for Mesp2-null mice, indicating that these Tbx6 binding sites are indispensable for Mesp2 expression. T-box binding to the consensus sequences in the Mesp2 upstream region was confirmed by chromatin immunoprecipitation assays. Further enhancer analyses indicated that the number and spatial organization of the T-box binding sites are critical for initiating Mesp2 transcription via Notch signaling. We also generated a knock-in mouse in which the endogenous Mesp2 enhancer was replaced by the core enhancer of medaka mespb, an ortholog of mouse Mesp2. The homozygous enhancer knock-in mouse was viable and showed normal skeletal segmentation, indicating that the medaka mespb enhancer functionally replaced the mouse Mesp2 enhancer. These results demonstrate that there is significant evolutionary conservation of Mesp regulatory mechanisms between fish and mice.

  5. Small molecule-directed specification of sclerotome-like chondroprogenitors and induction of a somitic chondrogenesis program from embryonic stem cells.

    Science.gov (United States)

    Zhao, Jiangang; Li, Songhui; Trilok, Suprita; Tanaka, Makoto; Jokubaitis-Jameson, Vanta; Wang, Bei; Niwa, Hitoshi; Nakayama, Naoki

    2014-10-01

    Pluripotent embryonic stem cells (ESCs) generate rostral paraxial mesoderm-like progeny in 5-6 days of differentiation induced by Wnt3a and Noggin (Nog). We report that canonical Wnt signaling introduced either by forced expression of activated β-catenin, or the small-molecule inhibitor of Gsk3, CHIR99021, satisfied the need for Wnt3a signaling, and that the small-molecule inhibitor of BMP type I receptors, LDN193189, was able to replace Nog. Mesodermal progeny generated using such small molecules were chondrogenic in vitro, and expressed trunk paraxial mesoderm markers such as Tcf15 and Meox1, and somite markers such as Uncx, but failed to express sclerotome markers such as Pax1. Induction of the osteochondrogenically committed sclerotome from somite requires sonic hedgehog and Nog. Consistently, Pax1 and Bapx1 expression was induced when the isolated paraxial mesodermal progeny were treated with SAG1 (a hedgehog receptor agonist) and LDN193189, then Sox9 expression was induced, leading to cartilaginous nodules and particles in the presence of BMP, indicative of chondrogenesis via sclerotome specification. By contrast, treatment with TGFβ also supported chondrogenesis and stimulated Sox9 expression, but failed to induce the expression of Pax1 and Bapx1. On ectopic transplantation to immunocompromised mice, the cartilage particles developed under either condition became similarly mineralized and formed pieces of bone with marrow. Thus, the use of small molecules led to the effective generation from ESCs of paraxial mesodermal progeny, and to their further differentiation in vitro through sclerotome specification into growth plate-like chondrocytes, a mechanism resembling in vivo somitic chondrogenesis that is not recapitulated with TGFβ. © 2014. Published by The Company of Biologists Ltd.

  6. PRMT8 Controls the Pluripotency and Mesodermal Fate of Human Embryonic Stem Cells By Enhancing the PI3K/AKT/SOX2 Axis.

    Science.gov (United States)

    Jeong, Ho-Chang; Park, Soon-Jung; Choi, Jong-Jin; Go, Young-Hyun; Hong, Soon-Ki; Kwon, Ok-Seon; Shin, Joong-Gon; Kim, Rae-Kwon; Lee, Mi-Ok; Lee, Su-Jae; Shin, Hyoung Doo; Moon, Sung-Hwan; Cha, Hyuk-Jin

    2017-09-01

    Basic fibroblast growth factor (bFGF) supplementation is critical to maintain the pluripotency of human pluripotent stem cells (hPSCs) through activation of PI3K/AKT, rather than MEK/ERK pathway. Thus, elaborate molecular mechanisms that preserve PI3K/AKT signaling upon bFGF stimulation may exist in hPSCs. Protein arginine methyltransferase 8 (PRMT8) was expressed and then its level gradually decreased during spontaneous differentiation of human embryonic stem cells (hESCs). PRMT8 loss- or gain-of-function studies demonstrated that PRMT8 contributed to longer maintenance of hESC pluripotency, even under bFGF-deprived conditions. Direct interaction of membrane-localized PRMT8 with p85, a regulatory subunit of PI3K, was associated with accumulation of phosphoinositol 3-phosphate and consequently high AKT activity. Furthermore, the SOX2 induction, which was controlled by the PRMT8/PI3K/AKT axis, was linked to mesodermal lineage differentiation. Thus, we propose that PRMT8 in hESCs plays an important role not only in maintaining pluripotency but also in controlling mesodermal differentiation through bFGF signaling toward the PI3K/AKT/SOX2 axis. Stem Cells 2017;35:2037-2049. © 2017 AlphaMed Press.

  7. PSA-NCAM-Negative Neural Crest Cells Emerging during Neural Induction of Pluripotent Stem Cells Cause Mesodermal Tumors and Unwanted Grafts

    Science.gov (United States)

    Lee, Dongjin R.; Yoo, Jeong-Eun; Lee, Jae Souk; Park, Sanghyun; Lee, Junwon; Park, Chul-Yong; Ji, Eunhyun; Kim, Han-Soo; Hwang, Dong-Youn; Kim, Dae-Sung; Kim, Dong-Wook

    2015-01-01

    Summary Tumorigenic potential of human pluripotent stem cells (hPSCs) is an important issue in clinical applications. Despite many efforts, PSC-derived neural precursor cells (NPCs) have repeatedly induced tumors in animal models even though pluripotent cells were not detected. We found that polysialic acid-neural cell adhesion molecule (PSA-NCAM)− cells among the early NPCs caused tumors, whereas PSA-NCAM+ cells were nontumorigenic. Molecular profiling, global gene analysis, and multilineage differentiation of PSA-NCAM− cells confirm that they are multipotent neural crest stem cells (NCSCs) that could differentiate into both ectodermal and mesodermal lineages. Transplantation of PSA-NCAM− cells in a gradient manner mixed with PSA-NCAM+ cells proportionally increased mesodermal tumor formation and unwanted grafts such as PERIPHERIN+ cells or pigmented cells in the rat brain. Therefore, we suggest that NCSCs are a critical target for tumor prevention in hPSC-derived NPCs, and removal of PSA-NCAM− cells eliminates the tumorigenic potential originating from NCSCs after transplantation. PMID:25937368

  8. La teoría del rayo paraxial en la sismica de pozo: Aproximación de segundo orden en los tiempos de tránsito

    Directory of Open Access Journals (Sweden)

    Montes Vides Luis Alfredo

    2001-08-01

    Full Text Available

    Using the paraxial ray approximation of the named geometric optics a set of numerical expressions were found, these expressions characterize reflecting events recorded in detectors placed in a borehole. One of them is the characteristic travel time function which estimates the travel times of reflecting events in a vertical seismic profile configuration with sources placed in surface in the vicinity of the boreholes´s top. This characteristic VSP function can be numerically estimated using at least six measurements of appropriated selected travel times.

    Others expressions were deduced to allow the transformation of the VSP travel time function in the equivalent COP travel time function corresponding to reflecting events recorded in surface in a common midpoint array. The use of this result will make possible to solve the inverse problem in the neighborhood of the borehole by the application of downward continuation techniques of the travel time function. The results are valid only in the approximation of the second order of the travel times in models which consist of a pile of homogeneous and isotropic layers of any velocities and densities, separated by smooth interfaces arbitrarily curved.

    Utilizando la aproximación del rayo paraxial de la llamada óptica geométrica se encontró un conjunto de expresiones que caracterizan los eventos de reflexión que han sido registrados en detectores situados dentro de un pozo. Una de ellas es la función característica que estima

  9. The C. elegans Spalt-like protein SEM-4 functions through the SoxC transcription factor SEM-2 to promote a proliferative blast cell fate in the postembryonic mesoderm.

    Science.gov (United States)

    Shen, Qinfang; Shi, Herong; Tian, Chenxi; Ghai, Vikas; Liu, Jun

    2017-09-01

    Proper development of a multicellular organism relies on well-coordinated regulation of cell fate specification, cell proliferation and cell differentiation. The C. elegans postembryonic mesoderm provides a useful system for uncovering factors involved in these processes and for further dissecting their regulatory relationships. The single Spalt-like zinc finger containing protein SEM-4/SALL is known to be involved in specifying the proliferative sex myoblast (SM) fate. We have found that SEM-4/SALL is sufficient to promote the SM fate and that it does so in a cell autonomous manner. We further showed that SEM-4/SALL acts through the SoxC transcription factor SEM-2 to promote the SM fate. SEM-2 is known to promote the SM fate by inhibiting the expression of two BWM-specifying transcription factors. In light of recent findings in mammals showing that Sall4, one of the mammalian homologs of SEM-4, contributes to pluripotency regulation by inhibiting differentiation, our work suggests that the function of SEM-4/SALL proteins in regulating pluripotency versus differentiation appears to be evolutionarily conserved. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Graphical user interface based computer simulation of self-similar modes of a paraxial slow self-focusing laser beam for saturating plasma nonlinearities

    International Nuclear Information System (INIS)

    Batra, Karuna; Mitra, Sugata; Subbarao, D.; Sharma, R.P.; Uma, R.

    2005-01-01

    The task for the present study is to make an investigation of self-similarity in a self-focusing laser beam both theoretically and numerically using graphical user interface based interactive computer simulation model in MATLAB (matrix laboratory) software in the presence of saturating ponderomotive force based and relativistic electron quiver based plasma nonlinearities. The corresponding eigenvalue problem is solved analytically using the standard eikonal formalism and the underlying dynamics of self-focusing is dictated by the corrected paraxial theory for slow self-focusing. The results are also compared with computer simulation of self-focusing by the direct fast Fourier transform based spectral methods. It is found that the self-similar solution obtained analytically oscillates around the true numerical solution equating it at regular intervals. The simulation results are the main ones although a feasible semianalytical theory under many assumptions is given to understand the process. The self-similar profiles are called as self-organized profiles (not in a strict sense), which are found to be close to Laguerre-Gaussian curves for all the modes, the shape being conserved. This terminology is chosen because it has already been shown from a phase space analysis that the width of an initially Gaussian beam undergoes periodic oscillations that are damped when any absorption is added in the model, i.e., the beam width converges to a constant value. The research paper also tabulates the specific values of the normalized phase shift for solutions decaying to zero at large transverse distances for first three modes which can, however, be extended to higher order modes

  11. Metamerism in cephalochordates and the problem of the vertebrate head.

    Science.gov (United States)

    Onai, Takayuki; Adachi, Noritaka; Kuratani, Shigeru

    2017-01-01

    The vertebrate head characteristically exhibits a complex pattern with sense organs, brain, paired eyes and jaw muscles, and the brain case is not found in other chordates. How the extant vertebrate head has evolved remains enigmatic. Historically, there have been two conflicting views on the origin of the vertebrate head, segmental and non-segmental views. According to the segmentalists, the vertebrate head is organized as a metameric structure composed of segments equivalent to those in the trunk; a metamere in the vertebrate head was assumed to consist of a somite, a branchial arch and a set of cranial nerves, considering that the head evolved from rostral segments of amphioxus-like ancestral vertebrates. Non-segmentalists, however, considered that the vertebrate head was not segmental. In that case, the ancestral state of the vertebrate head may be non-segmented, and rostral segments in amphioxus might have been secondarily gained, or extant vertebrates might have evolved through radical modifications of amphioxus-like ancestral vertebrate head. Comparative studies of mesodermal development in amphioxus and vertebrate gastrula embryos have revealed that mesodermal gene expressions become segregated into two domains anteroposteriorly to specify the head mesoderm and trunk mesoderm only in vertebrates; in this segregation, key genes such as delta and hairy, involved in segment formation, are expressed in the trunk mesoderm, but not in the head mesoderm, strongly suggesting that the head mesoderm of extant vertebrates is not segmented. Taken together, the above finding possibly adds a new insight into the origin of the vertebrate head; the vertebrate head mesoderm would have evolved through an anteroposterior polarization of the paraxial mesoderm if the ancestral vertebrate had been amphioxus-like.

  12. Tissue Reactivity of the 14F7 Mab Raised against N-Glycolyl GM3 Ganglioside in Tumors of Neuroectodermal, Mesodermal, and Epithelial Origin

    Science.gov (United States)

    Blanco, Rancés; Quintana, Yisel; Blanco, Damián; Cedeño, Mercedes; Rengifo, Charles E.; Frómeta, Milagros; Ríos, Martha; Rengifo, Enrique; Carr, Adriana

    2013-01-01

    The expression of N-glycolylneuraminic acid forming the structure of gangliosides and/or other glycoconjugates (Hanganutziu-Deicher antigen) in human has been considered as a tumor-associated antigen. Specifically, some reports of 14F7 Mab (a highly specific Mab raised against N-glycolyl GM3 ganglioside) reactivity in human tumors have been recently published. Nevertheless, tumors of epithelial origin have been mostly evaluated. The goal of the present paper was to evaluate the immunohistochemical recognition of 14F7 Mab in different human tumors of neuroectodermal, mesodermal, and epithelial origins using an immunoperoxidase staining method. Samples of fetal, normal, and reactive astrocytosis of the brain were also included in the study. In general, nontumoral tissues, as well as, low-grade brain tumors showed no or a limited immunoreaction with 14F7 Mab. Nevertheless, high-grade astrocytomas (III-IV) and neuroblastomas, as well as, sarcomas and thyroid carcinomas were mostly reactive with 14F7. No reaction was evidenced in medulloblastomas and ependymoblastomas. Our data suggest that the expression of N-glycolyl GM3 ganglioside could be related to the aggressive behavior of malignant cells, without depending on the tumor origin. Our data could also support the possible use of N-glycolyl GM3 as a target for both active and passive immunotherapies of malignancies expressing this molecule. PMID:26317019

  13. Does the mesodermal derangement in Chiari Type I malformation extend to the cervical spine? Evidence from an analytical morphometric study on cervical paraspinal muscles.

    Science.gov (United States)

    Thakar, Sumit; Kurudi Siddappa, Avinash; Aryan, Saritha; Mohan, Dilip; Sai Kiran, Narayanam Anantha; Hegde, Alangar S

    2017-10-01

    OBJECTIVE The mesodermal derangement in Chiari Type I malformation (CMI) has been postulated to encompass the cervical spine. The objectives of this study were to assess the cross-sectional areas (CSAs) of cervical paraspinal muscles (PSMs) in patients with CMI without syringomyelia, compare them with those in non-CMI subjects, and evaluate their correlations with various factors. METHODS In this retrospective study, the CSAs of cervical PSMs in 25 patients were calculated on T2-weighted axial MR images and computed as ratios with respect to the corresponding vertebral body areas. These values and the cervical taper ratios were then compared with those of age- and sex-matched non-CMI subjects and analyzed with respect to demographic data and clinicoradiological factors. RESULTS Compared with the non-CMI group, the mean CSA values for the rectus capitis minor and all of the subaxial PSMs were lower in the study group, and those of the deep extensors were significantly lower (p = 0.004). The cervical taper ratio was found to be significantly higher in the study cohort (p = 0.0003). A longer duration of symptoms and a steeper cervical taper ratio were independently associated with lower CSA values for the deep extensors (p = 0.04 and p = 0.03, respectively). The presence of neck pain was associated with a lower CSA value for the deep flexors (p = 0.03). CONCLUSIONS Patients with CMI demonstrate alterations in their cervical paraspinal musculature even in the absence of coexistent syringomyelia. Their deep extensor muscles undergo significant atrophic changes that worsen with the duration of their symptoms. This could be related to a significantly steeper cervical taper ratio that their cervical cords are exposed to. Neck pain in these patients is related to atrophy of their deep flexor muscles. A steeper cervical taper ratio and alterations in the PSMs could be additional indicators for surgery in patients with CMI without syringomyelia.

  14. Self-focusing and filamentation of a laser beam within the paraxial stationary approximation. Part I: theoretical aspects; Autofocalisation et filamentation d`un faisceau laser dans le cadre de l`approximation paraxiale et stationnaire. Partie I: aspects theoriques

    Energy Technology Data Exchange (ETDEWEB)

    Blain, M A; Bonnaud, G; Chiron, A; Riazuelo, G

    1996-02-01

    This report addresses the propagation of an intense laser beam in a unmagnetized plasma, which is relevant for both the inertial confinement fusion (ICF) and the ultra-high intensity (UHI) pulses. The width and the irradiance of the laser pulses are respectively: (0.1-10) nanosecond and (10{sup 13}-10{sup 16}) W/cm{sup 2} for the ICF context and (0.1-1) picosecond and in excess of 10{sup 18} W/cm{sup 2} for the UHI context. The nonlinear mechanisms for beam self-focusing and filamentation, induced by both the ponderomotive expelling of charged particles and the relativistic increase of the electron mass, are specified studied. Part I deals with the theoretical aspects and part II is concerned with the results of two-dimensional simulations. The results have been obtained within the framework of the paraxial approximation and the stationary response of the plasma. The large set of scenarios that characterize the behavior of Gaussian beam and a modulated beam is presented; a synthetic overview of the previous theoretical works is also provided. The interplay of two crossing beams is discussed. This report will be a help to improve the uniformity of the laser irradiation in the ICF context and to channel a very intense laser beam over large distance in the UHI context. (authors). 53 refs., 11 figs., 3 tabs.

  15. Mitosis-associated repression in development.

    Science.gov (United States)

    Esposito, Emilia; Lim, Bomyi; Guessous, Ghita; Falahati, Hanieh; Levine, Michael

    2016-07-01

    Transcriptional repression is a pervasive feature of animal development. Here, we employ live-imaging methods to visualize the Snail repressor, which establishes the boundary between the presumptive mesoderm and neurogenic ectoderm of early Drosophila embryos. Snail target enhancers were attached to an MS2 reporter gene, permitting detection of nascent transcripts in living embryos. The transgenes exhibit initially broad patterns of transcription but are refined by repression in the mesoderm following mitosis. These observations reveal a correlation between mitotic silencing and Snail repression. We propose that mitosis and other inherent discontinuities in transcription boost the activities of sequence-specific repressors, such as Snail. © 2016 Esposito et al.; Published by Cold Spring Harbor Laboratory Press.

  16. Watch-ing out for chick limb development.

    Science.gov (United States)

    Pascoal, Susana; Palmeirim, Isabel

    2007-09-01

    Time control is a crucial issue during embryonic development. Nevertheless, little is known about how embryonic cells measure time. Until recently, the only molecular clock known to operate during vertebrate embryonic development was the somitogenesis clock, exclusively functioning in coordinating the precise timing of each new pair of somites formed from the presomitic mesoderm. We have recently evidenced that a similar molecular clock also underlies the timing at which autopod chondrogenic precursors are laid down to form a skeletal limb element. In addition, we herein suggest that the molecular clock is not the only parallelism that can be established between somitogenesis and limb-bud development. In an evolutionary perspective, we support the previously proposed idea that the molecular mechanisms involved in the segmentation of the body axis may have been partially reused in the mesoderm of the lateral plate, thereby allowing the emergence of paired appendages.

  17. Development of the annelid axochord: insights into notochord evolution.

    Science.gov (United States)

    Lauri, Antonella; Brunet, Thibaut; Handberg-Thorsager, Mette; Fischer, Antje H L; Simakov, Oleg; Steinmetz, Patrick R H; Tomer, Raju; Keller, Philipp J; Arendt, Detlev

    2014-09-12

    The origin of chordates has been debated for more than a century, with one key issue being the emergence of the notochord. In vertebrates, the notochord develops by convergence and extension of the chordamesoderm, a population of midline cells of unique molecular identity. We identify a population of mesodermal cells in a developing invertebrate, the marine annelid Platynereis dumerilii, that converges and extends toward the midline and expresses a notochord-specific combination of genes. These cells differentiate into a longitudinal muscle, the axochord, that is positioned between central nervous system and axial blood vessel and secretes a strong collagenous extracellular matrix. Ancestral state reconstruction suggests that contractile mesodermal midline cells existed in bilaterian ancestors. We propose that these cells, via vacuolization and stiffening, gave rise to the chordate notochord. Copyright © 2014, American Association for the Advancement of Science.

  18. Bose-Einstein condensation of paraxial light

    OpenAIRE

    Klaers, J.; Schmitt, J.; Damm, T.; Vewinger, F.; Weitz, M.

    2011-01-01

    Photons, due to the virtually vanishing photon-photon interaction, constitute to very good approximation an ideal Bose gas, but owing to the vanishing chemical potential a (free) photon gas does not show Bose-Einstein condensation. However, this is not necessarily true for a lower-dimensional photon gas. By means of a fluorescence induced thermalization process in an optical microcavity one can achieve a thermal photon gas with freely adjustable chemical potential. Experimentally, we have obs...

  19. Bose-Einstein condensation of paraxial light

    Science.gov (United States)

    Klaers, J.; Schmitt, J.; Damm, T.; Vewinger, F.; Weitz, M.

    2011-10-01

    Photons, due to the virtually vanishing photon-photon interaction, constitute to very good approximation an ideal Bose gas, but owing to the vanishing chemical potential a (free) photon gas does not show Bose-Einstein condensation. However, this is not necessarily true for a lower-dimensional photon gas. By means of a fluorescence induced thermalization process in an optical microcavity one can achieve a thermal photon gas with freely adjustable chemical potential. Experimentally, we have observed thermalization and subsequently Bose-Einstein condensation of the photon gas at room temperature. In this paper, we give a detailed description of the experiment, which is based on a dye-filled optical microcavity, acting as a white-wall box for photons. Thermalization is achieved in a photon number-conserving way by photon scattering off the dye molecules, and the cavity mirrors both provide an effective photon mass and a confining potential-key prerequisites for the Bose-Einstein condensation of photons. The experimental results are in good agreement with both a statistical and a simple rate equation model, describing the properties of the thermalized photon gas.

  20. Sall4-Gli3 system in early limb progenitors is essential for the development of limb skeletal elements

    OpenAIRE

    Akiyama, Ryutaro; Kawakami, Hiroko; Wong, Julia; Oishi, Isao; Nishinakamura, Ryuichi; Kawakami, Yasuhiko

    2015-01-01

    The limb skeletal elements that have unique morphology and distinct locations are developed from limb progenitors, derived from the lateral plate mesoderm. These skeletal elements arise during limb development. In this study, we show genetic evidence that function of Sall4 is essential prior to limb outgrowth for development of the anterior-proximal skeletal elements. Furthermore, genetic interaction between Sall4 and Gli3 is upstream of establishing Shh (Sonic hedgehog) expression, and there...

  1. Differentiation defect in neural crest-derived smooth muscle cells in patients with aortopathy associated with bicuspid aortic valves

    Directory of Open Access Journals (Sweden)

    Jiao Jiao

    2016-08-01

    Full Text Available Individuals with bicuspid aortic valves (BAV are at a higher risk of developing thoracic aortic aneurysms (TAA than patients with trileaflet aortic valves (TAV. The aneurysms associated with BAV most commonly involve the ascending aorta and spare the descending aorta. Smooth muscle cells (SMCs in the ascending and descending aorta arise from neural crest (NC and paraxial mesoderm (PM, respectively. We hypothesized defective differentiation of the neural crest stem cells (NCSCs-derived SMCs but not paraxial mesoderm cells (PMCs-derived SMCs contributes to the aortopathy associated with BAV. When induced pluripotent stem cells (iPSCs from BAV/TAA patients were differentiated into NCSC-derived SMCs, these cells demonstrated significantly decreased expression of marker of SMC differentiation (MYH11 and impaired contraction compared to normal control. In contrast, the PMC-derived SMCs were similar to control cells in these aspects. The NCSC-SMCs from the BAV/TAA also showed decreased TGF-β signaling based on phosphorylation of SMAD2, and increased mTOR signaling. Inhibition of mTOR pathway using rapamycin rescued the aberrant differentiation. Our data demonstrates that decreased differentiation and contraction of patient's NCSC-derived SMCs may contribute to that aortopathy associated with BAV.

  2. Development of an embryonic skeletogenic mesenchyme lineage in a sea cucumber reveals the trajectory of change for the evolution of novel structures in echinoderms

    Directory of Open Access Journals (Sweden)

    McCauley Brenna S

    2012-08-01

    Full Text Available Abstract Background The mechanisms by which the conserved genetic “toolkit” for development generates phenotypic disparity across metazoans is poorly understood. Echinoderm larvae provide a great resource for understanding how developmental novelty arises. The sea urchin pluteus larva is dramatically different from basal echinoderm larval types, which include the auricularia-type larva of its sister taxon, the sea cucumbers, and the sea star bipinnaria larva. In particular, the pluteus has a mesodermally-derived larval skeleton that is not present in sea star larvae or any outgroup taxa. To understand the evolutionary origin of this structure, we examined the molecular development of mesoderm in the sea cucumber, Parastichopus parvimensis. Results By comparing gene expression in sea urchins, sea cucumbers and sea stars, we partially reconstructed the mesodermal regulatory state of the echinoderm ancestor. Surprisingly, we also identified expression of the transcription factor alx1 in a cryptic skeletogenic mesenchyme lineage in P. parvimensis. Orthologs of alx1 are expressed exclusively within the sea urchin skeletogenic mesenchyme, but are not expressed in the mesenchyme of the sea star, which suggests that alx1+ mesenchyme is a synapomorphy of at least sea urchins and sea cucumbers. Perturbation of Alx1 demonstrates that this protein is necessary for the formation of the sea cucumber spicule. Overexpression of the sea star alx1 ortholog in sea urchins is sufficient to induce additional skeleton, indicating that the Alx1 protein has not evolved a new function during the evolution of the larval skeleton. Conclusions The proposed echinoderm ancestral mesoderm state is highly conserved between the morphologically similar, but evolutionarily distant, auricularia and bipinnaria larvae. However, the auricularia, but not bipinnaria, also develops a simple skelotogenic cell lineage. Our data indicate that the first step in acquiring these novel

  3. Razvoj skeletno-mišičnega sistema in kože: Embryonic development of the musculoskeletal and integumentary system:

    OpenAIRE

    Legan, Mateja

    2005-01-01

    The author presents embryological development of the musculoskeletal system and the skin. Although they are basically both mesodermal in origin, the article emphasises the ectodermal origin of head bones, certain small smooth muscles and skin epidermis, with accent on the segmental origin of musculoskeletal regions. Development of the dermis and epidermal adnexes is clearly explained. For better understanding, some clinical correlates to developmental problems are shown as well. Avtorica p...

  4. In vivo functional requirement of the mouse Ifitm1 gene for germ cell development, interferon mediated immune response and somitogenesis.

    Directory of Open Access Journals (Sweden)

    Ingeborg Klymiuk

    Full Text Available The mammalian Interferon induced transmembrane protein 1 (Ifitm1 gene was originally identified as a member of a gene family highly inducible by type I and type II interferons. Based on expression analyses, it was suggested to be required for normal primordial germ cell migration. The knockdown of Ifitm1 in mouse embryos provided evidence for a role in somitogenesis. We generated the first targeted knockin allele of the Ifitm1 gene to systematically reassess all inferred functions. Sperm motility and the fertility of male and female mutant mice are as in wild type littermates. Embryonic somites and the adult vertebral column appear normal in homozygous Ifitm1 knockout mice, demonstrating that Ifitm1 is not essential for normal segmentation of the paraxial mesoderm. Proportions of leucocyte subsets, including granulocytes, monocytes, B-cells, T-cells, NK-cells, and NKT-cells, are unchanged in mutant mice. Based on a normal immune response to Listeria monocytogenes infection, there is no evidence for a dysfunction in downstream IFNγ signaling in Ifitm1 mutant mice. Expression from the Ifitm1 locus from E8.5 to E14.5 is highly dynamic. In contrast, in adult mice, Ifitm1 expression is highly restricted and strong in the bronchial epithelium. Intriguingly, IFITM1 is highly overexpressed in tumor epithelia cells of human squamous cell carcinomas and in adenocarcinomas of NSCLC patients. These analyses underline the general importance of targeted in vivo studies for the functional annotation of the mammalian genome. The first comprehensive description of the Ifitm1 expression pattern provides a rational basis for the further examination of Ifitm1 gene functions. Based on our data, the fact that IFITM1 can function as a negative regulator of cell proliferation, and because the gene maps to chromosome band 11p15.5, previously associated with NSCLC, it is likely that IFITM1 in man has a key role in tumor formation.

  5. BMP-Mediated Functional Cooperation between Dlx5;Dlx6 and Msx1;Msx2 during Mammalian Limb Development

    Science.gov (United States)

    Vieux-Rochas, Maxence; Bouhali, Kamal; Mantero, Stefano; Garaffo, Giulia; Provero, Paolo; Astigiano, Simonetta; Barbieri, Ottavia; Caratozzolo, Mariano F.; Tullo, Apollonia; Guerrini, Luisa; Lallemand, Yvan; Robert, Benoît

    2013-01-01

    The Dlx and Msx homeodomain transcription factors play important roles in the control of limb development. The combined disruption of Msx1 and Msx2, as well as that of Dlx5 and Dlx6, lead to limb patterning defects with anomalies in digit number and shape. Msx1;Msx2 double mutants are characterized by the loss of derivatives of the anterior limb mesoderm which is not observed in either of the simple mutants. Dlx5;Dlx6 double mutants exhibit hindlimb ectrodactyly. While the morphogenetic action of Msx genes seems to involve the BMP molecules, the mode of action of Dlx genes still remains elusive. Here, examining the limb phenotypes of combined Dlx and Msx mutants we reveal a new Dlx-Msx regulatory loop directly involving BMPs. In Msx1;Dlx5;Dlx6 triple mutant mice (TKO), beside the expected ectrodactyly, we also observe the hallmark morphological anomalies of Msx1;Msx2 double mutants suggesting an epistatic role of Dlx5 and Dlx6 over Msx2. In Msx2;Dlx5;Dlx6 TKO mice we only observe an aggravation of the ectrodactyly defect without changes in the number of the individual components of the limb. Using a combination of qPCR, ChIP and bioinformatic analyses, we identify two Dlx/Msx regulatory pathways: 1) in the anterior limb mesoderm a non-cell autonomous Msx-Dlx regulatory loop involves BMP molecules through the AER and 2) in AER cells and, at later stages, in the limb mesoderm the regulation of Msx2 by Dlx5 and Dlx6 occurs also cell autonomously. These data bring new elements to decipher the complex AER-mesoderm dialogue that takes place during limb development and provide clues to understanding the etiology of congenital limb malformations. PMID:23382810

  6. BMP-mediated functional cooperation between Dlx5;Dlx6 and Msx1;Msx2 during mammalian limb development.

    Directory of Open Access Journals (Sweden)

    Maxence Vieux-Rochas

    Full Text Available The Dlx and Msx homeodomain transcription factors play important roles in the control of limb development. The combined disruption of Msx1 and Msx2, as well as that of Dlx5 and Dlx6, lead to limb patterning defects with anomalies in digit number and shape. Msx1;Msx2 double mutants are characterized by the loss of derivatives of the anterior limb mesoderm which is not observed in either of the simple mutants. Dlx5;Dlx6 double mutants exhibit hindlimb ectrodactyly. While the morphogenetic action of Msx genes seems to involve the BMP molecules, the mode of action of Dlx genes still remains elusive. Here, examining the limb phenotypes of combined Dlx and Msx mutants we reveal a new Dlx-Msx regulatory loop directly involving BMPs. In Msx1;Dlx5;Dlx6 triple mutant mice (TKO, beside the expected ectrodactyly, we also observe the hallmark morphological anomalies of Msx1;Msx2 double mutants suggesting an epistatic role of Dlx5 and Dlx6 over Msx2. In Msx2;Dlx5;Dlx6 TKO mice we only observe an aggravation of the ectrodactyly defect without changes in the number of the individual components of the limb. Using a combination of qPCR, ChIP and bioinformatic analyses, we identify two Dlx/Msx regulatory pathways: 1 in the anterior limb mesoderm a non-cell autonomous Msx-Dlx regulatory loop involves BMP molecules through the AER and 2 in AER cells and, at later stages, in the limb mesoderm the regulation of Msx2 by Dlx5 and Dlx6 occurs also cell autonomously. These data bring new elements to decipher the complex AER-mesoderm dialogue that takes place during limb development and provide clues to understanding the etiology of congenital limb malformations.

  7. BMP-mediated functional cooperation between Dlx5;Dlx6 and Msx1;Msx2 during mammalian limb development.

    Science.gov (United States)

    Vieux-Rochas, Maxence; Bouhali, Kamal; Mantero, Stefano; Garaffo, Giulia; Provero, Paolo; Astigiano, Simonetta; Barbieri, Ottavia; Caratozzolo, Mariano F; Tullo, Apollonia; Guerrini, Luisa; Lallemand, Yvan; Robert, Benoît; Levi, Giovanni; Merlo, Giorgio R

    2013-01-01

    The Dlx and Msx homeodomain transcription factors play important roles in the control of limb development. The combined disruption of Msx1 and Msx2, as well as that of Dlx5 and Dlx6, lead to limb patterning defects with anomalies in digit number and shape. Msx1;Msx2 double mutants are characterized by the loss of derivatives of the anterior limb mesoderm which is not observed in either of the simple mutants. Dlx5;Dlx6 double mutants exhibit hindlimb ectrodactyly. While the morphogenetic action of Msx genes seems to involve the BMP molecules, the mode of action of Dlx genes still remains elusive. Here, examining the limb phenotypes of combined Dlx and Msx mutants we reveal a new Dlx-Msx regulatory loop directly involving BMPs. In Msx1;Dlx5;Dlx6 triple mutant mice (TKO), beside the expected ectrodactyly, we also observe the hallmark morphological anomalies of Msx1;Msx2 double mutants suggesting an epistatic role of Dlx5 and Dlx6 over Msx2. In Msx2;Dlx5;Dlx6 TKO mice we only observe an aggravation of the ectrodactyly defect without changes in the number of the individual components of the limb. Using a combination of qPCR, ChIP and bioinformatic analyses, we identify two Dlx/Msx regulatory pathways: 1) in the anterior limb mesoderm a non-cell autonomous Msx-Dlx regulatory loop involves BMP molecules through the AER and 2) in AER cells and, at later stages, in the limb mesoderm the regulation of Msx2 by Dlx5 and Dlx6 occurs also cell autonomously. These data bring new elements to decipher the complex AER-mesoderm dialogue that takes place during limb development and provide clues to understanding the etiology of congenital limb malformations.

  8. The Pleural Mesothelium in Development and Disease

    Directory of Open Access Journals (Sweden)

    Hitesh eBatra

    2014-08-01

    Full Text Available The pleural mesothelium, derived from the embryonic mesoderm, is formed by a metabolically active monolayer of cells that blanket the chest wall and lungs on the parietal and visceral surfaces, respectively. The pleura and lungs are formed as a result of an intricate relationship between the mesoderm and the endoderm during development. Pleural Mesothelial Cells (PMCs are known to express Wilms tumor-1 (Wt1 gene and in lineage labeling studies of the developing embryo, PMCs were found to track into the lung parenchyma and undergo mesothelial-mesenchymal transition (MMT to form α-smooth muscle actin (α-SMA-positive cells of the mesenchyme and vasculature. There is definite evidence that mesothelial cells can differentiate and this seems to play an important role in pleural and parenchymal pathologies. Mesothelial cells can differentiate into adipocytes, chondrocytes and osteoblasts; and have been shown to clonally generate fibroblasts and smooth muscle cells in murine models. This supports the possibility that they may also modulate lung injury-repair by re-activation of developmental programs in the adult reflecting an altered recapitulation of development, with implications for regenerative biology of the lung.

  9. Morphological diversity of the avian foot is related with the pattern of msx gene expression in the developing autopod.

    Science.gov (United States)

    Gañan, Y; Macias, D; Basco, R D; Merino, R; Hurle, J M

    1998-04-01

    The formation of the digits in amniota embryos is accompanied by apoptotic cell death of the interdigital mesoderm triggered through BMP signaling. Differences in the intensity of this apoptotic process account for the establishment of the different morphological types of feet observed in amniota (i.e., free-digits, webbed digits, lobulated digits). The molecular basis accounting for the differential pattern of interdigital cell death remains uncertain since the reduction of cell death in species with webbed digits is not accompanied by a parallel reduction in the pattern of expression of bmp genes in the interdigital regions. In this study we show that the duck interdigital web mesoderm exhibits an attenuated response to both BMP-induced apoptosis and TGFbeta-induced chondrogenesis in comparison with species with free digits. The attenuated response to these signals is accompanied by a reduced pattern of expression of msx-1 and msx-2 genes. Local application of FGF in the duck interdigit expands the domain of msx-2 expression but not the domain of msx-1 expression. This change in the expression of msx-2 is followed by a parallel increase in spontaneous and exogenous BMP-induced interdigital cell death, while the chondrogenic response to TGFbetas is unchanged. The regression of AER, as deduced by the pattern of extinction of fgf-8 expression, takes place in a similar fashion in the chick and duck regardless of the differences in interdigital cell death and msx gene expression. Implantation of BMP-beads in the distal limb mesoderm induces AER regression in both the chick and duck. This finding suggests an additional role for BMPs in the physiological regression of the AER. It is proposed that the formation of webbed vs free-digit feet in amniota results from a premature differentiation of the interdigital mesoderm into connective tissue caused by a reduced expression of msx genes in the developing autopod. Copyright 1998 Academic Press.

  10. Development and Tissue Origins of the Mammalian Cranial Base

    Science.gov (United States)

    Iseki, S.; Bamforth, S. D.; Olsen, B. R.; Morriss-Kay, G. M.

    2008-01-01

    The vertebrate cranial base is a complex structure composed of bone, cartilage and other connective tissues underlying the brain; it is intimately connected with development of the face and cranial vault. Despite its central importance in craniofacial development, morphogenesis and tissue origins of the cranial base have not been studied in detail in the mouse, an important model organism. We describe here the location and time of appearance of the cartilages of the chondrocranium. We also examine the tissue origins of the mouse cranial base using a neural crest cell lineage cell marker, Wnt1-Cre/R26R, and a mesoderm lineage cell marker, Mesp1-Cre/R26R. The chondrocranium develops between E11 and E16 in the mouse, beginning with development of the caudal (occipital) chondrocranium, followed by chondrogenesis rostrally to form the nasal capsule, and finally fusion of these two parts via the midline central stem and the lateral struts of the vault cartilages. X-Gal staining of transgenic mice from E8.0 to 10 days post-natal showed that neural crest cells contribute to all of the cartilages that form the ethmoid, presphenoid, and basisphenoid bones with the exception of the hypochiasmatic cartilages. The basioccipital bone and non-squamous parts of the temporal bones are mesoderm derived. Therefore the prechordal head is mostly composed of neural crest-derived tissues, as predicted by the New Head Hypothesis. However, the anterior location of the mesoderm-derived hypochiasmatic cartilages, which are closely linked with the extra-ocular muscles, suggests that some tissues associated with the visual apparatus may have evolved independently of the rest of the “New Head”. PMID:18680740

  11. Expression of the metastasis-associated mts1 gene during mouse development

    DEFF Research Database (Denmark)

    Klingelhöfer, Jörg; Ambartsumian, N S; Lukanidin, E M

    1997-01-01

    motility. In order to understand the function of this gene, we studied the expression of the mts1 mRNA and protein in vivo during mouse development. Both mRNA and protein were present in high concentrations from 12.5 to 18.5 days post coitum (dpc) in a variety of developing embryonic tissue of mesodermal....... In developing bone, Mts1 was expressed in invasive mesenchymal cells and in osteoclasts. The results presented here suggest that Mtsl plays an important role in mouse development during differentiation and function of macrophages and might be involved in different processes associated with mesenchymal...

  12. Identification of a spatially specific enhancer element in the chicken Msx-2 gene that regulates its expression in the apical ectodermal ridge of the developing limb buds of transgenic mice.

    Science.gov (United States)

    Sumoy, L; Wang, C K; Lichtler, A C; Pierro, L J; Kosher, R A; Upholt, W B

    1995-07-01

    Msx-2 is a member of the Msx family of homeobox-containing genes expressed in a variety of embryonic tissues involved in epithelial-mesenchymal interactions and pattern formation. In the developing chick limb bud, Msx-2 is expressed in the apical ectodermal ridge, which plays a crucial role in directing the growth and patterning of limb mesoderm. In addition, Msx-2 is expressed in the anterior nonskeletal-forming mesoderm of the limb bud, in the posterior necrotic zone, and in the interdigital mesenchyme. Studies of the altered expression patterns of Msx-2 in amelic and polydactylous mutant chick limbs have suggested that the apical ectodermal ridge and mesodermal domains of Msx-2 expression are independently regulated and that there might be separate cis-regulatory elements in the Msx-2 gene controlling its spatially distinct domains of expression. To test this hypothesis, we have isolated the chicken Msx-2 gene and have tested the ability of various regions of the gene to target expression of LacZ reporter gene to specific regions of the limbs of transgenic mice. A variety of these constructs are consistently expressed only in the apical ectodermal ridge and the ectoderm of the genital tubercle and are not expressed in the mesoderm of the limb bud or in other regions of the embryo where the endogenous Msx-2 gene is expressed. These results suggest the presence of spatially specific cis-regulatory elements in the Msx-2 gene. We identified a 348-bp region in the 5' flanking region of the Msx-2 gene which can act as an apical ectodermal ridge enhancer element when placed in reverse orientation in front of the reporter gene with transcription initiation directed by the minimal hsp68 promoter.

  13. Enhanced differentiation of human embryonic stem cells to mesenchymal progenitors by inhibition of TGF-beta/Activin/Nodal signaling using SB-431542

    DEFF Research Database (Denmark)

    Mahmood, Amer; Harkness, Linda; Schrøder, Henrik Daa

    2010-01-01

    Directing differentiation of human embryonic stem cells (hESC) into specific cell types using an easy and reproducible protocol is a prerequisite for the clinical use of hESC in regenerative medicine procedures. Here, we report a protocol for directing the differentiation of hESC into mesenchymal...... in vivo. Interestingly, SB-OG cells cultured in 10% fetal bovine serum (FBS) developed into a homogeneous population of mesenchymal progenitors that expressed CD markers characteristic of mesenchymal stem cells (MSC): CD44(+) (100%), CD73(+) (98%), CD146(+) (96%) and CD166(+) (88%) with the ability...... progenitor cells. We demonstrate that inhibition of TGF-beta/Activin/Nodal signaling during embryoid bodies (EB) formation using SB-431542 (SB) in serum free medium, markedly up-regulated paraxial mesodermal markers (TBX6, TBX5), and several myogenic developmental markers including early myogenic...

  14. Immunohistochemical markers for corneal stem cells in the early developing human eye

    DEFF Research Database (Denmark)

    Lyngholm, Mikkel; Høyer, Poul E; Vorum, Henrik

    2008-01-01

    niche (week 14) in human embryos and fetuses. The expression of SOD2 and CK15 was investigated together with other recently identified limbal proteins. Previously suggested LSC and differentiation markers (PAX6, aquaporin-1 and nestin) were also investigated. Both SOD2 and CK15 were present...... markers and potential markers for LSCs and early transient amplifying cells in human adults. In this study, we describe the development of the ectodermally derived LSCs and the mesodermally derived niche cells from the time at which the cornea is defined (week 6) until the formation of the early limbal...

  15. Development of the pulmonary vein and the systemic venous sinus: an interactive 3D overview.

    Directory of Open Access Journals (Sweden)

    Gert van den Berg

    Full Text Available Knowledge of the normal formation of the heart is crucial for the understanding of cardiac pathologies and congenital malformations. The understanding of early cardiac development, however, is complicated because it is inseparably associated with other developmental processes such as embryonic folding, formation of the coelomic cavity, and vascular development. Because of this, it is necessary to integrate morphological and experimental analyses. Morphological insights, however, are limited by the difficulty in communication of complex 3D-processes. Most controversies, in consequence, result from differences in interpretation, rather than observation. An example of such a continuing debate is the development of the pulmonary vein and the systemic venous sinus, or "sinus venosus". To facilitate understanding, we present a 3D study of the developing venous pole in the chicken embryo, showing our results in a novel interactive fashion, which permits the reader to form an independent opinion. We clarify how the pulmonary vein separates from a greater vascular plexus within the splanchnic mesoderm. The systemic venous sinus, in contrast, develops at the junction between the splanchnic and somatic mesoderm. We discuss our model with respect to normal formation of the heart, congenital cardiac malformations, and the phylogeny of the venous tributaries.

  16. Jacob's ladder of approximations to paraxial dynamic electron scattering

    OpenAIRE

    Lubk, A.; Rusz, Jan

    2015-01-01

    Dynamical scattering theory describes the dominant scattering process of beam electrons at targets in the transmission electron microscope (TEM). Hence, practically every quantitative TEM study has to consider its ramifications, typically by some approximate modeling. Here, we elaborate on a hierarchy within the various approximations focusing on the two principal approaches used in practice, Bloch wave and multislice. We reveal characteristic differences in the capability of these methods to...

  17. Development of the carapacial ridge: implications for the evolution of genetic networks in turtle shell development.

    Science.gov (United States)

    Moustakas, Jacqueline E

    2008-01-01

    Paleontologists and neontologists have long looked to development to understand the homologies of the dermal bones that form the "armor" of turtles, crocodiles, armadillos, and other vertebrates. This study shows molecular evidence supporting a dermomyotomal identity for the mesenchyme of the turtle carapacial ridge. The mesenchyme of the carapace primordium expresses Pax3, Twist1, Dermo1, En1, Sim1, and Gremlin at early stages and before overt ossification expresses Pax1. A hypothesis is proposed that this mesenchyme forms dermal bone in the turtle carapace. A comparison of regulatory gene expression in the primordia of the turtle carapace, the vertebrate limb, and the vertebral column implies the exaptation of key genetic networks in the development of the turtle shell. This work establishes a new role for this mesodermal compartment and highlights the importance of changes in genetic regulation in the evolution of morphology.

  18. The developing dorsal ganglion of the salp Thalia democratica, and the nature of the ancestral chordate brain

    Science.gov (United States)

    C.Lacalli, T.

    1998-01-01

    The development of the dorsal ganglion of the salp, Thalia democratica, is described from electron microscope reconstructions up to the stage of central neuropile formation. The central nervous system (CNS) rudiment is initially tubular with an open central canal. Early developmental events include: (i) the formation of a thick dorsal mantle of neuroblasts from which paired dorsal paraxial neuropiles arise; (ii) the differentiation of clusters of primary motor neurons along the ventral margin of the mantle; and (iii) the development from the latter of a series of peripheral nerves. The dorsal paraxial neuropiles ultimately connect to the large central neuropile, which develops later. Direct contact between neuroblasts and muscle appears to be involved in the development of some anterior nerves. The caudal nerves responsible for innervating more distant targets in the posterior part of the body develop without such contacts, which suggests that a different patterning mechanism may be employed in this part of the neuromuscular system. The results are compared with patterns of brain organization in other chordates. Because the salp CNS is symmetrical and generally less reduced than that of ascidian larvae, it is more easily compared with the CNS of amphioxus and vertebrates. The dorsal paraxial centres in the salp resemble the dorsolateral tectal centres in amphioxus in both position and organization; the central neuropile in salps likewise resembles the translumenal system in amphioxus. The neurons themselves are similar in that many of their neurites appear to be derived from the apical surface instead of the basal surface of the cell. Such neurons, with extensively developed apical neurites, may represent a new cell type that evolved in the earliest chordates in conjunction with the formation of translumenal or intralumenal integrative centres. In comparing the salp ganglion with vertebrates, we suggest that the main core of the ganglion is most like the mes

  19. Activation of the Arterial Program Drives Development of Definitive Hemogenic Endothelium with Lymphoid Potential

    Directory of Open Access Journals (Sweden)

    Mi Ae Park

    2018-05-01

    Full Text Available Summary: Understanding the pathways guiding the development of definitive hematopoiesis with lymphoid potential is essential for advancing human pluripotent stem cell (hPSC technologies for the treatment of blood diseases and immunotherapies. In the embryo, lymphoid progenitors and hematopoietic stem cells (HSCs arise from hemogenic endothelium (HE lining arteries but not veins. Here, we show that activation of the arterial program through ETS1 overexpression or by modulating MAPK/ERK signaling pathways at the mesodermal stage of development dramatically enhanced the formation of arterial-type HE expressing DLL4 and CXCR4. Blood cells generated from arterial HE were more than 100-fold enriched in T cell precursor frequency and possessed the capacity to produce B lymphocytes and red blood cells expressing high levels of BCL11a and β-globin. Together, these findings provide an innovative strategy to aid in the generation of definitive lymphomyeloid progenitors and lymphoid cells from hPSCs for immunotherapy through enhancing arterial programming of HE. : Park et al. find that activation of the arterial program through ETS1 overexpression or by modulating MAPK/ERK signaling pathways at the mesodermal stage of development dramatically enhances formation of arterial-type hemogenic endothelium (HE from hPSCs. Blood cells generated from arterial HE are highly enriched in definitive lymphomyeloid progenitors. Keywords: human pluripotent stem cells, hemogenic endothelium, T cells, hematopoietic stem cells, hematopoiesis, ETS1, MAPK/ERK signaling

  20. Clarifying tetrapod embryogenesis by a dorso-ventral analysis of the tissue flows during early stages of chicken development.

    Science.gov (United States)

    Fleury, Vincent

    2012-09-01

    The formation of an animal body remains largely a mystery. It is still not clear whether anything like an organization plan or an "archetype" as coined by Darwin himself, actually exists, or whether animals are organized by a succession of stop-and-go genetic, non-linear, instructions with no global pattern. Nevertheless, it was recognized long ago that the early stages of amniote development consist of large scale rotatory movements over a discoidal blastula (Wetzel, 1924). Such rotatory movements reshuffle a mass inside a finite volume, and thus may have to bear physical conservation laws which contribute to establish the plan of animals in a global fashion. In this article I use dual dorso-ventral imaging of the chicken blastula, to show experimentally that the global movement of early vertebrate embryogenesis is organized with a very simple topology, around and away of a series of hyperbolic points in the vector flow of movement. At the first hyperbolic point, a layer of tissue (the mesoderm) ingresses and moves as a viscous sheet radially. It is found that the sheet flows away with a scaling law for the radius R(t)∼exp(t/τ). Also, the movement of this mesoderm changes the flow on the other layer (the ectoderm) by the principle of action and reaction. By mesoderm wetting the ectoderm, the first hyperbolic point migrates from the anal region, to the umbilical region. The final location of the hyperbolic point defines eventually the central part of the body (the umbilical region). Thus, the formation of the vertebrate body is fixed, as a global movement, by the dynamics of singular points in the visco-elastic flow, governed by mechanical forces within the tissue. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  1. Rac1 modulates cardiomyocyte adhesion during mouse embryonic development

    Energy Technology Data Exchange (ETDEWEB)

    Abu-Issa, Radwan, E-mail: rabuissa@umich.edu

    2015-01-24

    Highlights: • Conditional knockout of Rac1 using Nkx2.5 Cre line is lethal at E13.5. • The myocardium of the mutant is thin and disorganized. • The phenotype is not due to cardiomyocyte low proliferation or apoptosis. • The phenotype is due to specific defect in cardiomyocyte adhesion. - Abstract: Rac1, a member of the Rho subfamily of small GTPases, is involved in morphogenesis and differentiation of many cell types. Here we define a role of Rac1 in cardiac development by specifically deleting Rac1 in the pre-cardiac mesoderm using the Nkx2.5-Cre transgenic driver line. Rac1-conditional knockout embryos initiate heart development normally until embryonic day 11.5 (E11.5); their cardiac mesoderm is specified, and the heart tube is formed and looped. However, by E12.5-E13.5 the mutant hearts start failing and embryos develop edema and hemorrhage which is probably the cause for the lethality observed soon after. The hearts of Rac1-cKO embryos exhibit disorganized and thin myocardial walls and defects in outflow tract alignment. No significant differences of cardiomyocyte death or proliferation were found between developing control and mutant embryos. To uncover the role of Rac1 in the heart, E11.5 primary heart cells were cultured and analyzed in vitro. Rac1-deficient cardiomyocytes were less spread, round and loosely attached to the substrate and to each other implying that Rac1-mediated signaling is required for appropriate cell–cell and/or cellmatrix adhesion during cardiac development.

  2. Rac1 modulates cardiomyocyte adhesion during mouse embryonic development

    International Nuclear Information System (INIS)

    Abu-Issa, Radwan

    2015-01-01

    Highlights: • Conditional knockout of Rac1 using Nkx2.5 Cre line is lethal at E13.5. • The myocardium of the mutant is thin and disorganized. • The phenotype is not due to cardiomyocyte low proliferation or apoptosis. • The phenotype is due to specific defect in cardiomyocyte adhesion. - Abstract: Rac1, a member of the Rho subfamily of small GTPases, is involved in morphogenesis and differentiation of many cell types. Here we define a role of Rac1 in cardiac development by specifically deleting Rac1 in the pre-cardiac mesoderm using the Nkx2.5-Cre transgenic driver line. Rac1-conditional knockout embryos initiate heart development normally until embryonic day 11.5 (E11.5); their cardiac mesoderm is specified, and the heart tube is formed and looped. However, by E12.5-E13.5 the mutant hearts start failing and embryos develop edema and hemorrhage which is probably the cause for the lethality observed soon after. The hearts of Rac1-cKO embryos exhibit disorganized and thin myocardial walls and defects in outflow tract alignment. No significant differences of cardiomyocyte death or proliferation were found between developing control and mutant embryos. To uncover the role of Rac1 in the heart, E11.5 primary heart cells were cultured and analyzed in vitro. Rac1-deficient cardiomyocytes were less spread, round and loosely attached to the substrate and to each other implying that Rac1-mediated signaling is required for appropriate cell–cell and/or cellmatrix adhesion during cardiac development

  3. Development.

    Science.gov (United States)

    Boydell, Tom

    1982-01-01

    Explores the theories and models of self-actualization and human development. Twelve tables illustrate developmental stages, ways of knowing, moral and ethical development, management style, goals of learning, organizational development, and other dimensions. Availability: M.E.A.D. Subscriptions, C.S.M.L., University of Lancaster, Lancaster LA1…

  4. Developer

    OpenAIRE

    Lakew, Lakachew

    2016-01-01

    As companies grow managing the work becomes harder and harder, thus the ad-vantages of technology come into hand for increasing communication and facili-tating work. This thesis documents the design and development of a web and mobile applica-tion for a service company. The web and mobile applications are built using Laravel and Android Studio respectively. These two applications are designed to communicate with one another so that similar data can be used across these two platforms. ...

  5. Indian hedgehog signaling from endothelial cells is required for sclera and retinal pigment epithelium development in the mouse eye.

    Science.gov (United States)

    Dakubo, Gabriel D; Mazerolle, Chantal; Furimsky, Marosh; Yu, Chuan; St-Jacques, Benoit; McMahon, Andrew P; Wallace, Valerie A

    2008-08-01

    The development of extraocular orbital structures, in particular the choroid and sclera, is regulated by a complex series of interactions between neuroectoderm, neural crest and mesoderm derivatives, although in many instances the signals that mediate these interactions are not known. In this study we have investigated the function of Indian hedgehog (Ihh) in the developing mammalian eye. We show that Ihh is expressed in a population of non-pigmented cells located in the developing choroid adjacent to the RPE. The analysis of Hh mutant mice demonstrates that the RPE and developing scleral mesenchyme are direct targets of Ihh signaling and that Ihh is required for the normal pigmentation pattern of the RPE and the condensation of mesenchymal cells to form the sclera. Our findings also indicate that Ihh signals indirectly to promote proliferation and photoreceptor specification in the neural retina. This study identifies Ihh as a novel choroid-derived signal that regulates RPE, sclera and neural retina development.

  6. Assessing the bipotency of in vitro-derived neuromesodermal progenitors [v1; ref status: indexed, http://f1000r.es/58z

    Directory of Open Access Journals (Sweden)

    Anestis Tsakiridis

    2015-04-01

    Full Text Available Retrospective clonal analysis in the mouse has demonstrated that the posterior spinal cord neurectoderm and paraxial mesoderm share a common bipotent progenitor. These neuromesodermal progenitors (NMPs are the source of new axial structures during embryonic rostrocaudal axis elongation and are marked by the simultaneous co-expression of the transcription factors T(Brachyury (T(Bra and Sox2. NMP-like cells have recently been derived from pluripotent stem cells in vitro following combined stimulation of Wnt and fibroblast growth factor (FGF signaling. Under these conditions the majority of cultures consist of T(Bra/Sox2 co-expressing cells after 48-72 hours of differentiation. Although the capacity of these cells to generate posterior neural and paraxial mesoderm derivatives has been demonstrated at the population level, it is unknown whether a single in vitro-derived NMP can give rise to both neural and mesodermal cells. Here we demonstrate that T(Bra positive cells obtained from mouse epiblast stem cells (EpiSCs after culture in NMP-inducing conditions can generate both neural and mesodermal clones. This finding suggests that, similar to their embryonic counterparts, in vitro-derived NMPs are truly bipotent and can thus be exploited as a model for studying the molecular basis of developmental cell fate decisions.

  7. Expression of hLAMP-1-Positive Particles During Early Heart Development in the Chick.

    Science.gov (United States)

    Abd-Elhamid, T H; Conway, M L; Sinning, A R

    2017-10-01

    Heart development requires coordinated activity of various factors, the disturbance of which can lead to congenital heart defects. Heart lectin-associated matrix protein-1 (hLAMP-1) is a matrix protein expressed within Hensen's node at Hamburger-Hamilton (HH) stage 4, in the lateral mesoderm by HH stages 5-6 and enhanced within the left pre-cardiac field at HH stage 7. At HH stages 15-16, hLAMP-1 expression is observed in the atrioventricular canal and the outflow tract. Also, the role of hLAMP-1 in induction of mesenchyme formation in chick heart has been well documented. To further elucidate the role of this molecule in heart development, we examined its expression patterns during HH stages 8-14 in the chick. In this regard, we immunostained sections of the heart during HH stages 8-14 with antibodies specific to hLAMP-1. Our results showed prominent expression of hLAMP-1-positive particles in the extracellular matrix associated with the pre-cardiac mesoderm, the endoderm, ectoderm as well as neuroectoderm at HH stages 8-9. After formation of the linear heart tube at HH stage 10, the expression of hLAMP-1-stained particles disappears in those regions of original contact between the endoderm and heart forming fields due to rupture of the dorsal mesocardium while their expression becomes confined to the arterial and venous poles of the heart tube. This expression pattern is maintained until HH stage 14. This expression pattern suggests that hLAMP-1 may be involved in the formation of the endocardial tube. © 2017 Blackwell Verlag GmbH.

  8. Isl1 expression at the venous pole identifies a novel role for the second heart field in cardiac development.

    Science.gov (United States)

    Snarr, Brian S; O'Neal, Jessica L; Chintalapudi, Mastan R; Wirrig, Elaine E; Phelps, Aimee L; Kubalak, Steven W; Wessels, Andy

    2007-11-09

    The right ventricle and outflow tract of the developing heart are derived from mesodermal progenitor cells from the second heart field (SHF). SHF cells have been characterized by expression of the transcription factor Islet-1 (Isl1). Although Isl1 expression has also been reported in the venous pole, the specific contribution of the SHF to this part of the heart is unknown. Here we show that Isl1 is strongly expressed in the dorsal mesenchymal protrusion (DMP), a non-endocardially-derived mesenchymal structure involved in atrioventricular septation. We further demonstrate that abnormal development of the SHF-derived DMP is associated with the pathogenesis of atrioventricular septal defects. These results identify a novel role for the SHF.

  9. Inactivation of the Huntington's disease gene (Hdh impairs anterior streak formation and early patterning of the mouse embryo

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    Conlon Ronald A

    2005-08-01

    Full Text Available Abstract Background Huntingtin, the HD gene encoded protein mutated by polyglutamine expansion in Huntington's disease, is required in extraembryonic tissues for proper gastrulation, implicating its activities in nutrition or patterning of the developing embryo. To test these possibilities, we have used whole mount in situ hybridization to examine embryonic patterning and morphogenesis in homozygous Hdhex4/5 huntingtin deficient embryos. Results In the absence of huntingtin, expression of nutritive genes appears normal but E7.0–7.5 embryos exhibit a unique combination of patterning defects. Notable are a shortened primitive streak, absence of a proper node and diminished production of anterior streak derivatives. Reduced Wnt3a, Tbx6 and Dll1 expression signify decreased paraxial mesoderm and reduced Otx2 expression and lack of headfolds denote a failure of head development. In addition, genes initially broadly expressed are not properly restricted to the posterior, as evidenced by the ectopic expression of Nodal, Fgf8 and Gsc in the epiblast and T (Brachyury and Evx1 in proximal mesoderm derivatives. Despite impaired posterior restriction and anterior streak deficits, overall anterior/posterior polarity is established. A single primitive streak forms and marker expression shows that the anterior epiblast and anterior visceral endoderm (AVE are specified. Conclusion Huntingtin is essential in the early patterning of the embryo for formation of the anterior region of the primitive streak, and for down-regulation of a subset of dynamic growth and transcription factor genes. These findings provide fundamental starting points for identifying the novel cellular and molecular activities of huntingtin in the extraembryonic tissues that govern normal anterior streak development. This knowledge may prove to be important for understanding the mechanism by which the dominant polyglutamine expansion in huntingtin determines the loss of neurons in

  10. Inactivation of the Huntington's disease gene (Hdh) impairs anterior streak formation and early patterning of the mouse embryo.

    Science.gov (United States)

    Woda, Juliana M; Calzonetti, Teresa; Hilditch-Maguire, Paige; Duyao, Mabel P; Conlon, Ronald A; MacDonald, Marcy E

    2005-08-18

    Huntingtin, the HD gene encoded protein mutated by polyglutamine expansion in Huntington's disease, is required in extraembryonic tissues for proper gastrulation, implicating its activities in nutrition or patterning of the developing embryo. To test these possibilities, we have used whole mount in situ hybridization to examine embryonic patterning and morphogenesis in homozygous Hdh(ex4/5) huntingtin deficient embryos. In the absence of huntingtin, expression of nutritive genes appears normal but E7.0-7.5 embryos exhibit a unique combination of patterning defects. Notable are a shortened primitive streak, absence of a proper node and diminished production of anterior streak derivatives. Reduced Wnt3a, Tbx6 and Dll1 expression signify decreased paraxial mesoderm and reduced Otx2 expression and lack of headfolds denote a failure of head development. In addition, genes initially broadly expressed are not properly restricted to the posterior, as evidenced by the ectopic expression of Nodal, Fgf8 and Gsc in the epiblast and T (Brachyury) and Evx1 in proximal mesoderm derivatives. Despite impaired posterior restriction and anterior streak deficits, overall anterior/posterior polarity is established. A single primitive streak forms and marker expression shows that the anterior epiblast and anterior visceral endoderm (AVE) are specified. Huntingtin is essential in the early patterning of the embryo for formation of the anterior region of the primitive streak, and for down-regulation of a subset of dynamic growth and transcription factor genes. These findings provide fundamental starting points for identifying the novel cellular and molecular activities of huntingtin in the extraembryonic tissues that govern normal anterior streak development. This knowledge may prove to be important for understanding the mechanism by which the dominant polyglutamine expansion in huntingtin determines the loss of neurons in Huntington's disease.

  11. Neural crest stem cell population in craniomaxillofacial development and tissue repair

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    M La Noce

    2014-10-01

    Full Text Available Neural crest cells, delaminating from the neural tube during migration, undergo an epithelial-mesenchymal transition and differentiate into several cell types strongly reinforcing the mesoderm of the craniofacial body area – giving rise to bone, cartilage and other tissues and cells of this human body area. Recent studies on craniomaxillofacial neural crest-derived cells have provided evidence for the tremendous plasticity of these cells. Actually, neural crest cells can respond and adapt to the environment in which they migrate and the cranial mesoderm plays an important role toward patterning the identity of the migrating neural crest cells. In our experience, neural crest-derived stem cells, such as dental pulp stem cells, can actively proliferate, repair bone and give rise to other tissues and cytotypes, including blood vessels, smooth muscle, adipocytes and melanocytes, highlighting that their use in tissue engineering is successful. In this review, we provide an overview of the main pathways involved in neural crest formation, delamination, migration and differentiation; and, in particular, we concentrate our attention on the translatability of the latest scientific progress. Here we try to suggest new ideas and strategies that are needed to fully develop the clinical use of these cells. This effort should involve both researchers/clinicians and improvements in good manufacturing practice procedures. It is important to address studies towards clinical application or take into consideration that studies must have an effective therapeutic prospect for humans. New approaches and ideas must be concentrated also toward stem cell recruitment and activation within the human body, overcoming the classical grafting.

  12. APOPTOSIS DURING HUMAN FETAL KIDNEY DEVELOPMENT

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    Rade Čukuranović

    2005-01-01

    Full Text Available Kidney morphogenesis is a complex and stepwise process. The formation of mature kidney in mammals is preceded by two primitive embryonic kidneys known as pronephros and mesonephros. Metanephros develops as a result of reciprocal inductive interactions between two primordial mesodermal derivates: ureteric bud, an epithelial outgrowth of the Wolffian duct, and metanephric blastema, a group of mesenchymal cells. The ureteric bud induces the metanephric mesenchyme to differentiate and form nephrons, whilst the metanephric mesenchyme induces the ureteric bud to grow and branch to form collecting ducts. The nephron goes through four developmental stages, which are described as: 1 vesicle, 2 comma-shaped and S-shaped stages, 3 developing capillary loop, and finally 4 maturing glomerulus. Apoptosis (programmed cell death is a predominant form of physiological cell death, by which organism eliminate unwanted or damaged cells. It is the major component of normal development and disease. Apoptosis is the result of series of biochemical processes happening in certain order in a dying cell, among which the most important is activation of enzyme families called caspases which influence different cell components. Apoptosis is characterized by membrane blebbing, shrinkage of the cell, nuclear fragmentation and chromatin condensation. Organelles are preserved almost intact. Cell surface molecules change. A variety of physiological and pathological stimuli can initiate apoptosis. They act via receptor mechanisms, through biochemical agents, or cause DNA and cell membrane damage. Apoptosis is an important component of fetal development. It is thought that apoptosis is the one of the main regulatory events involved in kidney morphogenesis, considering that among great number of developed cells, only a few of them are involved in the developing program by escaping apoptosis. In any period during kidney development about 3 to 5%of cells are apoptotic. Thorough

  13. Student project of optical system analysis API-library development

    Science.gov (United States)

    Ivanova, Tatiana; Zhukova, Tatiana; Dantcaranov, Ruslan; Romanova, Maria; Zhadin, Alexander; Ivanov, Vyacheslav; Kalinkina, Olga

    2017-08-01

    In the paper API-library software developed by students of Applied and Computer Optics Department (ITMO University) for optical system design is presented. The library performs paraxial and real ray tracing, calculates 3d order (Seidel) aberration and real ray aberration of axis and non-axis beams (wave, lateral, longitudinal, coma, distortion etc.) and finally, approximate wave aberration by Zernike polynomials. Real aperture can be calculated by considering of real rays tracing failure on each surface. So far we assume optical system is centered, with spherical or 2d order aspherical surfaces. Optical glasses can be set directly by refraction index or by dispersion coefficients. The library can be used for education or research purposes in optical system design area. It provides ready to use software functions for optical system simulation and analysis that developer can simply plug into their software development for different purposes, for example for some specific synthesis tasks or investigation of new optimization modes. In the paper we present an example of using the library for development of cemented doublet synthesis software based on Slusarev's methodology. The library is used in optical system optimization recipes course for deep studying of optimization model and its application for optical system design. Development of such software is an excellent experience for students and help to understanding optical image modeling and quality analysis. This development is organized as student group joint project. We try to organize it as a group in real research and development project, so each student has his own role in the project and then use whole library functionality in his own master or bachelor thesis. Working in such group gives students useful experience and opportunity to work as research and development engineer of scientific software in the future.

  14. AKT signaling displays multifaceted functions in neural crest development.

    Science.gov (United States)

    Sittewelle, Méghane; Monsoro-Burq, Anne H

    2018-05-31

    AKT signaling is an essential intracellular pathway controlling cell homeostasis, cell proliferation and survival, as well as cell migration and differentiation in adults. Alterations impacting the AKT pathway are involved in many pathological conditions in human disease. Similarly, during development, multiple transmembrane molecules, such as FGF receptors, PDGF receptors or integrins, activate AKT to control embryonic cell proliferation, migration, differentiation, and also cell fate decisions. While many studies in mouse embryos have clearly implicated AKT signaling in the differentiation of several neural crest derivatives, information on AKT functions during the earliest steps of neural crest development had remained relatively scarce until recently. However, recent studies on known and novel regulators of AKT signaling demonstrate that this pathway plays critical roles throughout the development of neural crest progenitors. Non-mammalian models such as fish and frog embryos have been instrumental to our understanding of AKT functions in neural crest development, both in neural crest progenitors and in the neighboring tissues. This review combines current knowledge acquired from all these different vertebrate animal models to describe the various roles of AKT signaling related to neural crest development in vivo. We first describe the importance of AKT signaling in patterning the tissues involved in neural crest induction, namely the dorsal mesoderm and the ectoderm. We then focus on AKT signaling functions in neural crest migration and differentiation. Copyright © 2018 Elsevier Inc. All rights reserved.

  15. Nodal-dependent mesendoderm specification requires the combinatorial activities of FoxH1 and Eomesodermin.

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    Christopher E Slagle

    2011-05-01

    Full Text Available Vertebrate mesendoderm specification requires the Nodal signaling pathway and its transcriptional effector FoxH1. However, loss of FoxH1 in several species does not reliably cause the full range of loss-of-Nodal phenotypes, indicating that Nodal signals through additional transcription factors during early development. We investigated the FoxH1-dependent and -independent roles of Nodal signaling during mesendoderm patterning using a novel recessive zebrafish FoxH1 mutation called midway, which produces a C-terminally truncated FoxH1 protein lacking the Smad-interaction domain but retaining DNA-binding capability. Using a combination of gel shift assays, Nodal overexpression experiments, and genetic epistasis analyses, we demonstrate that midway more accurately represents a complete loss of FoxH1-dependent Nodal signaling than the existing zebrafish FoxH1 mutant schmalspur. Maternal-zygotic midway mutants lack notochords, in agreement with FoxH1 loss in other organisms, but retain near wild-type expression of markers of endoderm and various nonaxial mesoderm fates, including paraxial and intermediate mesoderm and blood precursors. We found that the activity of the T-box transcription factor Eomesodermin accounts for specification of these tissues in midway embryos. Inhibition of Eomesodermin in midway mutants severely reduces the specification of these tissues and effectively phenocopies the defects seen upon complete loss of Nodal signaling. Our results indicate that the specific combinations of transcription factors available for signal transduction play critical and separable roles in determining Nodal pathway output during mesendoderm patterning. Our findings also offer novel insights into the co-evolution of the Nodal signaling pathway, the notochord specification program, and the chordate branch of the deuterostome family of animals.

  16. Compartmentalised expression of Delta-like 1 in epithelial somites is required for the formation of intervertebral joints

    Directory of Open Access Journals (Sweden)

    Gossler Achim

    2007-06-01

    Full Text Available Abstract Background Expression of the mouse Delta-like 1 (Dll1 gene in the presomitic mesoderm and in the caudal halves of somites of the developing embryo is required for the formation of epithelial somites and for the maintenance of caudal somite identity, respectively. The rostro-caudal polarity of somites is initiated early on within the presomitic mesoderm in nascent somites. Here we have investigated the requirement of restricted Dll1 expression in caudal somite compartments for the maintenance of rostro-caudal somite polarity and the morphogenesis of the axial skeleton. We did this by overexpressing a functional copy of the Dll1 gene throughout the paraxial mesoderm, in particular in anterior somite compartments, during somitogenesis in transgenic mice. Results Epithelial somites were generated normally and appeared histologically normal in embryos of two independent Dll1 over-expressing transgenic lines. Gene expression analyses of rostro-caudal marker genes suggested that over-expression of Dll1 without restriction to caudal compartments was not sufficient to confer caudal identity to rostral somite halves in transgenic embryos. Nevertheless, Dll1 over-expression caused dysmorphologies of the axial skeleton, in particular, in morphological structures that derive from the articular joint forming compartment of vertebrae. Accordingly, transgenic animals exhibited missing or reduced intervertebral discs, rostral and caudal articular processes as well as costal heads of ribs. In addition, the midline of the vertebral column did not develop normally. Transgenic mice had open neural arches and split vertebral bodies with ectopic pseudo-growth plates. Endochondral bone formation and ossification in the developing vertebrae were delayed. Conclusion The mice overexpressing Dll1 exhibit skeletal dysmorphologies that are also evident in several mutant mice with defects in somite compartmentalisation. The Dll1 transgenic mice demonstrate that

  17. What are Head Cavities? - A History of Studies on Vertebrate Head Segmentation.

    Science.gov (United States)

    Kuratani, Shigeru; Adachi, Noritaka

    2016-06-01

    Motivated by the discovery of segmental epithelial coeloms, or "head cavities," in elasmobranch embryos toward the end of the 19th century, the debate over the presence of mesodermal segments in the vertebrate head became a central problem in comparative embryology. The classical segmental view assumed only one type of metamerism in the vertebrate head, in which each metamere was thought to contain one head somite and one pharyngeal arch, innervated by a set of cranial nerves serially homologous to dorsal and ventral roots of spinal nerves. The non-segmental view, on the other hand, rejected the somite-like properties of head cavities. A series of small mesodermal cysts in early Torpedo embryos, which were thought to represent true somite homologs, provided a third possible view on the nature of the vertebrate head. Recent molecular developmental data have shed new light on the vertebrate head problem, explaining that head mesoderm evolved, not by the modification of rostral somites of an amphioxus-like ancestor, but through the polarization of unspecified paraxial mesoderm into head mesoderm anteriorly and trunk somites posteriorly.

  18. Sonic hedgehog signaling in the development of the mouse hypothalamus

    Directory of Open Access Journals (Sweden)

    Sandra eBlaess

    2015-01-01

    Full Text Available The expression pattern of Sonic Hedgehog (Shh in the developing hypothalamus changes over time. Shh is initially expressed in the prechordal mesoderm and later in the hypothalamic neuroepithelium-- first medially, and then in two off-medial domains. This dynamic expression suggests that Shh might regulate several aspects of hypothalamic development. To gain insight into them, lineage tracing, (conditional gene inactivation in mouse, in ovo loss- and gain-of-function approaches in chick and analysis of Shh expression regulation have been employed. We will focus on mouse studies and refer to chick and fish when appropriate to clarify. These studies show that Shh-expressing neuroepithelial cells serve as a signaling center for neighboring precursors, and give rise to most of the basal hypothalamus (tuberal and mammillary regions. Shh signaling is initially essential for hypothalamic induction. Later, Shh signaling from the neuroepithelium controls specification of the lateral hypothalamic area and growth-patterning coordination in the basal hypothalamus. To further elucidate the role of Shh in hypothalamic development, it will be essential to understand how Shh regulates the downstream Gli transcription factors.

  19. Major regulatory factors in the evolution of development: the roles of goosecoid and Msx in the evolution of the direct-developing sea urchin Heliocidaris erythrogramma.

    Science.gov (United States)

    Wilson, Keen A; Andrews, Mary E; Rudolf Turner, F; Raff, Rudolf A

    2005-01-01

    The transcription factors Gsc and Msx are expressed in the oral ectoderm of the indirect-developing sea urchin Heliocidaris tuberculata. Their patterns of expression are highly modified in the direct developer Heliocidaris erythrogramma, which lacks an oral ectoderm. We here test the hypothesis that they are large effect genes responsible for the loss of the oral ectoderm module in the direct-developing larva of H. erythrogramma as well as for the restoration of an overt oral ectoderm in H.e. xH.t. hybrids. We undertook misexpression/overexpression and knockdown assays in the two species and in hybrids by mRNA injection. The results indicate that dramatic changes of function of these transcription factors has occurred. One of these genes, Gsc, has the ability when misexpressed to partially restore oral ectoderm in H. erythrogramma. On the other hand, Msx has lost any oral function and instead has a role in mesoderm proliferation and patterning. In addition, we found that the H. tuberculataGsc is up regulated in H.e. xH.t. hybrids, showing a preferential use of the indirect developing parental gene in the development of the hybrid. We suggest that Gsc qualifies as a gene of large evolutionary effect and is partially responsible for the evolution of direct development of H. erythrogramma. We discuss these results in light of modularity and genetic networks in development, as well as in their implications for the rapid evolution of large morphological changes in development.

  20. Transcriptional activity of Pax3 is co-activated by TAZ

    International Nuclear Information System (INIS)

    Murakami, Masao; Tominaga, Junji; Makita, Ryosuke; Uchijima, Yasunobu; Kurihara, Yukiko; Nakagawa, Osamu; Asano, Tomoichiro; Kurihara, Hiroki

    2006-01-01

    Pax3 is a transcription factor which functions in embryonic development and human diseases. In a yeast two-hybrid screen with full-length Pax3 as bait, we isolated a clone encoding transcriptional co-activator with PDZ-binding motif (TAZ) from an E10.5 mouse embryo cDNA library. Co-immunoprecipitation and nuclear co-localization of TAZ with Pax3 suggest that their association is functionally relevant. In situ hybridization revealed TAZ and Pax3 expression to partially overlap in the paraxial mesoderm, limb buds, and the neural tube. In C2C12 myoblast cells and NIH3T3 cells, TAZ enhanced the transcriptional activity of Pax3 on artificial and microphthalmia-associated transcription factor promoter-luciferase constructs, suggesting that TAZ can function as a co-activator of Pax3. Functional interaction between Pax3 and TAZ may provide a clue to clarifying the mechanism by which Pax3 serves as a transcriptional activator during embryogenesis

  1. Distinctive Roles of Canonical and Noncanonical Wnt Signaling in Human Embryonic Cardiomyocyte Development

    Directory of Open Access Journals (Sweden)

    Silvia Mazzotta

    2016-10-01

    Full Text Available Wnt signaling is a key regulator of vertebrate heart development; however, specific roles for human cardiomyocyte development remain uncertain. Here we use human embryonic stem cells (hESCs to analyze systematically in human cardiomyocyte development the expression of endogenous Wnt signaling components, monitor pathway activity, and dissect stage-specific requirements for canonical and noncanonical Wnt signaling mechanisms using small-molecule inhibitors. Our analysis suggests that WNT3 and WNT8A, via FZD7 and canonical signaling, regulate BRACHYURY expression and mesoderm induction; that WNT5A/5B, via ROR2 and noncanonical signaling, regulate MESP1 expression and cardiovascular development; and that later in development WNT2, WNT5A/5B, and WNT11, via FZD4 and FZD6, regulate functional cardiomyocyte differentiation via noncanonical Wnt signaling. Our findings confirm in human development previously proposed roles for canonical Wnt signaling in sequential stages of vertebrate cardiomyogenesis, and identify more precise roles for noncanonical signaling and for individual Wnt signal and Wnt receptor genes in human cardiomyocyte development.

  2. Influence and timing of arrival of murine neural crest on pancreatic beta cell development and maturation.

    Science.gov (United States)

    Plank, Jennifer L; Mundell, Nathan A; Frist, Audrey Y; LeGrone, Alison W; Kim, Thomas; Musser, Melissa A; Walter, Teagan J; Labosky, Patricia A

    2011-01-15

    Interactions between cells from the ectoderm and mesoderm influence development of the endodermally-derived pancreas. While much is known about how mesoderm regulates pancreatic development, relatively little is understood about how and when the ectodermally-derived neural crest regulates pancreatic development and specifically, beta cell maturation. A previous study demonstrated that signals from the neural crest regulate beta cell proliferation and ultimately, beta cell mass. Here, we expand on that work to describe timing of neural crest arrival at the developing pancreatic bud and extend our knowledge of the non-cell autonomous role for neural crest derivatives in the process of beta cell maturation. We demonstrated that murine neural crest entered the pancreatic mesenchyme between the 26 and 27 somite stages (approximately 10.0 dpc) and became intermingled with pancreatic progenitors as the epithelium branched into the surrounding mesenchyme. Using a neural crest-specific deletion of the Forkhead transcription factor Foxd3, we ablated neural crest cells that migrate to the pancreatic primordium. Consistent with previous data, in the absence of Foxd3, and therefore the absence of neural crest cells, proliferation of insulin-expressing cells and insulin-positive area are increased. Analysis of endocrine cell gene expression in the absence of neural crest demonstrated that, although the number of insulin-expressing cells was increased, beta cell maturation was significantly impaired. Decreased MafA and Pdx1 expression illustrated the defect in beta cell maturation; we discovered that without neural crest, there was a reduction in the percentage of insulin-positive cells that co-expressed Glut2 and Pdx1 compared to controls. In addition, transmission electron microscopy analyses revealed decreased numbers of characteristic insulin granules and the presence of abnormal granules in insulin-expressing cells from mutant embryos. Together, these data demonstrate that

  3. Gdf11 is a negative regulator of chondrogenesis and myogenesis in the developing chick limb.

    Science.gov (United States)

    Gamer, L W; Cox, K A; Small, C; Rosen, V

    2001-01-15

    GDF11, a new member of the TGF-beta gene superfamily, regulates anterior/posterior patterning in the axial skeleton during mouse embryogenesis. Gdf11 null mice display skeletal abnormalities that appear to represent anterior homeotic transformations of vertebrae consistent with high levels of Gdf11 expression in the primitive streak, presomitic mesoderm, and tail bud. However, despite strong Gdf11 expression in the limb throughout development, this structure does not appear to be affected in the knockout mice. In order to understand this dichotomy of Gdf11 expression versus Gdf11 function, we identified the chicken Gdf11 gene and studied its role during limb formation. In the early limb bud, Gdf11 transcripts are detected in the subectodermal mesoderm at the distal tip, in a region overlapping the progress zone. At these stages, Gdf11 is excluded from the central core mesenchyme where precartilaginous condensations will form. Later in development, Gdf11 continues to be expressed in the distal most mesenchyme and can also be detected more proximally, in between the forming skeletal elements. When beads incubated in GDF11 protein were implanted into the early wing bud, GDF11 caused severe truncations of the limb that affected both the cartilage elements and the muscle. Limb shortening appeared to be the result of an inhibition of chondrogenesis and myogenesis and using an in vitro micromass assay, we confirmed the negative effects of GDF11 on both myogenic and chondrogenic cell differentiation. Analysis of molecular markers of skeletal patterning revealed that GDF11 induced ectopic expression of Hoxd-11 and Hoxd-13, but not of Hoxa-11, Hoxa-13, or the Msx genes. These data suggest that GDF11 may be involved in controlling the late distal expression of the Hoxd genes during limb development and that misregulation of these Hox genes by excess GDF11 may cause some of the observed alterations in skeletal element shape. In addition, GDF11 induced the expression of its own

  4. Paraxial propagation of the first-order chirped Airy vortex beams in a chiral medium.

    Science.gov (United States)

    Xie, Jintao; Zhang, Jianbin; Ye, Junran; Liu, Haowei; Liang, Zhuoying; Long, Shangjie; Zhou, Kangzhu; Deng, Dongmei

    2018-03-05

    We introduce the propagation of the first-order chirped Airy vortex beams (FCAiV) in a chiral medium analytically. Results show that the FCAiV beams split into the left circularly polarized vortex (LCPV) beams and the right circularly polarized vortex (RCPV) beams, which have totally different propagation trajectories in the chiral medium. In this paper, we investigate the effects of the first-order chirped parameter β, the chiral parameter γ and the optical vortex on the propagation process of the FCAiV beams. It is shown that the propagation trajectory of the FCAiV beams declines with the chirped parameter increasing. Besides, the increase of the chiral parameter acting on the LCPV beams makes the relative position between the main lobe and the optical vortex further while the effect on the RCPV beams is the opposite. Furthermore, the relative position between the main lobe and the optical vortex contributes to the position of the intensity focusing. Meanwhile, with the chiral parameter increasing, the maximum gradient and scattering forces of the LCPV beams decrease but those of the RCPV beams will increase during the propagation. It is significant that we can control the propagation trajectory, the intensity focusing position and the radiation forces of the FCAiV beams by varying the chirped parameter and the chiral parameter.

  5. Propagation of high power electromagnetic beam in relativistic magnetoplasma: Higher order paraxial ray theory

    Science.gov (United States)

    Gill, Tarsem Singh; Kaur, Ravinder; Mahajan, Ranju

    2010-09-01

    This paper presents an analysis of self-consistent, steady-state, theoretical model, which explains the ring formation in a Gaussian electromagnetic beam propagating in a magnetoplasma, characterized by relativistic nonlinearity. Higher order terms (up to r4) in the expansion of the dielectric function and the eikonal have been taken into account. The condition for the formation of a dark and bright ring derived earlier by Misra and Mishra [J. Plasma Phys. 75, 769 (2009)] has been used to study focusing/defocusing of the beam. It is seen that inclusion of higher order terms does significantly affect the dependence of the beam width on the distance of propagation. Further, the effect of the magnetic field and the nature of nonlinearity on the ring formation and self-focusing of the beam have been explored.

  6. Propagation of high power electromagnetic beam in relativistic magnetoplasma: Higher order paraxial ray theory

    International Nuclear Information System (INIS)

    Gill, Tarsem Singh; Kaur, Ravinder; Mahajan, Ranju

    2010-01-01

    This paper presents an analysis of self-consistent, steady-state, theoretical model, which explains the ring formation in a Gaussian electromagnetic beam propagating in a magnetoplasma, characterized by relativistic nonlinearity. Higher order terms (up to r 4 ) in the expansion of the dielectric function and the eikonal have been taken into account. The condition for the formation of a dark and bright ring derived earlier by Misra and Mishra [J. Plasma Phys. 75, 769 (2009)] has been used to study focusing/defocusing of the beam. It is seen that inclusion of higher order terms does significantly affect the dependence of the beam width on the distance of propagation. Further, the effect of the magnetic field and the nature of nonlinearity on the ring formation and self-focusing of the beam have been explored.

  7. Lie-optic matrix algorithm for computer simulation of paraxial self ...

    Indian Academy of Sciences (India)

    It gives rise to a matrix method for self-focusing beam propagation that is ... are applicable for other media like linear optical fibers and to more general ..... operators for small slices of the plasma of thickness ¡z each, it is advisable to work.

  8. Polystyrene nanoparticles affect Xenopus laevis development

    Energy Technology Data Exchange (ETDEWEB)

    Tussellino, Margherita; Ronca, Raffaele [University of Naples Federico II, Department of Biology (Italy); Formiggini, Fabio [Italian Institute of Technology, Center for Advanced Biomaterials for Health Care IIT@CRIB (Italy); Marco, Nadia De [University of Naples Federico II, Department of Biology (Italy); Fusco, Sabato; Netti, Paolo Antonio [Italian Institute of Technology, Center for Advanced Biomaterials for Health Care IIT@CRIB (Italy); Carotenuto, Rosa, E-mail: rosa.carotenuto@unina.it [University of Naples Federico II, Department of Biology (Italy)

    2015-02-15

    Exposing living organisms to nanoparticulates is potentially hazardous, in particular when it takes place during embryogenesis. In this investigation, we have studied the effects of 50-nm-uncoated polystyrene nanoparticles (PSNPs) as a model to investigate the suitability of their possible future employments. We have used the standardized Frog Embryo Teratogenesis Assay-Xenopus test during the early stages of larval development of Xenopus laevis, and we have employed either contact exposure or microinjections. We found that the embryos mortality rate is dose dependent and that the survived embryos showed high percentage of malformations. They display disorders in pigmentation distribution, malformations of the head, gut and tail, edema in the anterior ventral region, and a shorter body length compared with sibling untreated embryos. Moreover, these embryos grow more slowly than the untreated embryos. Expressions of the mesoderm markers, bra (T-box Brachyury gene), myod1 (myogenic differentiation1), and of neural crest marker sox9 (sex SRY (determining region Y-box 9) transcription factor sox9), are modified. Confocal microscopy showed that the nanoparticles are localized in the cytoplasm, in the nucleus, and in the periphery of the digestive gut cells. Our data suggest that PSNPs are toxic and show a potential teratogenic effect for Xenopus larvae. We hypothesize that these effects may be due either to the amount of NPs that penetrate into the cells and/or to the “corona” effect caused by the interaction of PSNPs with cytoplasm components. The three endpoints of our study, i.e., mortality, malformations, and growth inhibition, suggest that the tests we used may be a powerful and flexible bioassay in evaluating pollutants in aquatic embryos.

  9. Polystyrene nanoparticles affect Xenopus laevis development

    International Nuclear Information System (INIS)

    Tussellino, Margherita; Ronca, Raffaele; Formiggini, Fabio; Marco, Nadia De; Fusco, Sabato; Netti, Paolo Antonio; Carotenuto, Rosa

    2015-01-01

    Exposing living organisms to nanoparticulates is potentially hazardous, in particular when it takes place during embryogenesis. In this investigation, we have studied the effects of 50-nm-uncoated polystyrene nanoparticles (PSNPs) as a model to investigate the suitability of their possible future employments. We have used the standardized Frog Embryo Teratogenesis Assay-Xenopus test during the early stages of larval development of Xenopus laevis, and we have employed either contact exposure or microinjections. We found that the embryos mortality rate is dose dependent and that the survived embryos showed high percentage of malformations. They display disorders in pigmentation distribution, malformations of the head, gut and tail, edema in the anterior ventral region, and a shorter body length compared with sibling untreated embryos. Moreover, these embryos grow more slowly than the untreated embryos. Expressions of the mesoderm markers, bra (T-box Brachyury gene), myod1 (myogenic differentiation1), and of neural crest marker sox9 (sex SRY (determining region Y-box 9) transcription factor sox9), are modified. Confocal microscopy showed that the nanoparticles are localized in the cytoplasm, in the nucleus, and in the periphery of the digestive gut cells. Our data suggest that PSNPs are toxic and show a potential teratogenic effect for Xenopus larvae. We hypothesize that these effects may be due either to the amount of NPs that penetrate into the cells and/or to the “corona” effect caused by the interaction of PSNPs with cytoplasm components. The three endpoints of our study, i.e., mortality, malformations, and growth inhibition, suggest that the tests we used may be a powerful and flexible bioassay in evaluating pollutants in aquatic embryos

  10. Hand in glove: brain and skull in development and dysmorphogenesis

    Science.gov (United States)

    Flaherty, Kevin

    2013-01-01

    The brain originates relatively early in development from differentiated ectoderm that forms a hollow tube and takes on an exceedingly complex shape with development. The skull is made up of individual bony elements that form from neural crest- and mesoderm-derived mesenchyme that unite to provide support and protection for soft tissues and spaces of the head. The meninges provide a protective and permeable membrane between brain and skull. Across evolutionary and developmental time, dynamic changes in brain and skull shape track one another so that their integration is evidenced in two structures that fit soundly regardless of changes in biomechanical and physiologic functions. Evidence for this tight correspondence is also seen in diseases of the craniofacial complex that are often classified as diseases of the skull (e.g., craniosynostosis) or diseases of the brain (e.g., holoprosencephaly) even when both tissues are affected. Our review suggests a model that links brain and skull morphogenesis through coordinated integration of signaling pathways (e.g., FGF, TGFβ, Wnt) via processes that are not currently understood, perhaps involving the meninges. Differences in the earliest signaling of biological structure establish divergent designs that will be enhanced during morphogenesis. Signaling systems that pattern the developing brain are also active in patterning required for growth and assembly of the skull and some members of these signaling families have been indicated as causal for craniofacial diseases. Because cells of early brain and skull are sensitive to similar signaling families, variation in the strength or timing of signals or shifts in patterning boundaries that affect one system (neural or skull) could also affect the other system and appropriate co-adjustments in development would be made. Interactions of these signaling systems and of the tissues that they pattern are fundamental to the consistent but labile functional and structural association

  11. In Vivo Human Somitogenesis Guides Somite Development from hPSCs

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    Haibin Xi

    2017-02-01

    Full Text Available Somites form during embryonic development and give rise to unique cell and tissue types, such as skeletal muscles and bones and cartilage of the vertebrae. Using somitogenesis-stage human embryos, we performed transcriptomic profiling of human presomitic mesoderm as well as nascent and developed somites. In addition to conserved pathways such as WNT-β-catenin, we also identified BMP and transforming growth factor β (TGF-β signaling as major regulators unique to human somitogenesis. This information enabled us to develop an efficient protocol to derive somite cells in vitro from human pluripotent stem cells (hPSCs. Importantly, the in-vitro-differentiating cells progressively expressed markers of the distinct developmental stages that are known to occur during in vivo somitogenesis. Furthermore, when subjected to lineage-specific differentiation conditions, the hPSC-derived somite cells were multipotent in generating somite derivatives, including skeletal myocytes, osteocytes, and chondrocytes. This work improves our understanding of human somitogenesis and may enhance our ability to treat diseases affecting somite derivatives.

  12. Murine craniofacial development requires Hdac3-mediated repression of Msx gene expression.

    Science.gov (United States)

    Singh, Nikhil; Gupta, Mudit; Trivedi, Chinmay M; Singh, Manvendra K; Li, Li; Epstein, Jonathan A

    2013-05-15

    Craniofacial development is characterized by reciprocal interactions between neural crest cells and neighboring cell populations of ectodermal, endodermal and mesodermal origin. Various genetic pathways play critical roles in coordinating the development of cranial structures by modulating the growth, survival and differentiation of neural crest cells. However, the regulation of these pathways, particularly at the epigenomic level, remains poorly understood. Using murine genetics, we show that neural crest cells exhibit a requirement for the class I histone deacetylase Hdac3 during craniofacial development. Mice in which Hdac3 has been conditionally deleted in neural crest demonstrate fully penetrant craniofacial abnormalities, including microcephaly, cleft secondary palate and dental hypoplasia. Consistent with these abnormalities, we observe dysregulation of cell cycle genes and increased apoptosis in neural crest structures in mutant embryos. Known regulators of cell cycle progression and apoptosis in neural crest, including Msx1, Msx2 and Bmp4, are upregulated in Hdac3-deficient cranial mesenchyme. These results suggest that Hdac3 serves as a critical regulator of craniofacial morphogenesis, in part by repressing core apoptotic pathways in cranial neural crest cells. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. DNA methyltransferase 3b is dispensable for mouse neural crest development.

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    Bridget T Jacques-Fricke

    Full Text Available The neural crest is a population of multipotent cells that migrates extensively throughout vertebrate embryos to form diverse structures. Mice mutant for the de novo DNA methyltransferase DNMT3b exhibit defects in two neural crest derivatives, the craniofacial skeleton and cardiac ventricular septum, suggesting that DNMT3b activity is necessary for neural crest development. Nevertheless, the requirement for DNMT3b specifically in neural crest cells, as opposed to interacting cell types, has not been determined. Using a conditional DNMT3b allele crossed to the neural crest cre drivers Wnt1-cre and Sox10-cre, neural crest DNMT3b mutants were generated. In both neural crest-specific and fully DNMT3b-mutant embryos, cranial neural crest cells exhibited only subtle migration defects, with increased numbers of dispersed cells trailing organized streams in the head. In spite of this, the resulting cranial ganglia, craniofacial skeleton, and heart developed normally when neural crest cells lacked DNMT3b. This indicates that DNTM3b is not necessary in cranial neural crest cells for their development. We conclude that defects in neural crest derivatives in DNMT3b mutant mice reflect a requirement for DNMT3b in lineages such as the branchial arch mesendoderm or the cardiac mesoderm that interact with neural crest cells during formation of these structures.

  14. Maternal Cortisol Mediates Hypothalamus-Pituitary-Interrenal Axis Development in Zebrafish

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    Nesan, Dinushan; Vijayan, Mathilakath M.

    2016-01-01

    In zebrafish (Danio rerio), de novo synthesis of cortisol in response to stressor exposure commences only after hatch. Maternally deposited cortisol is present during embryogenesis, but a role for this steroid in early development is unclear. We tested the hypothesis that maternal cortisol is essential for the proper development of hypothalamus-pituitary-interrenal (HPI) axis activity and the onset of the stressor-induced cortisol response in larval zebrafish. In this study, zygotic cortisol content was manipulated by microinjecting antibody to sequester this steroid, thereby making it unavailable during embryogenesis. This was compared with embryos containing excess cortisol by microinjection of exogenous steroid. The resulting larval phenotypes revealed distinct treatment effects, including deformed mesoderm structures when maternal cortisol was unavailable and cardiac edema after excess cortisol. Maternal cortisol unavailability heightened the cortisol stress response in post-hatch larvae, whereas excess cortisol abolished the stressor-mediated cortisol elevation. This contrasting hormonal response corresponded with altered expression of key HPI axis genes, including crf, 11B hydroxylase, pomca, and star, which were upregulated in response to reduced cortisol availability and downregulated when embryos had excess cortisol. These findings for the first time underscore a critical role for maternally deposited cortisol in programming HPI axis development and function in zebrafish. PMID:26940285

  15. Embryonic Development of the Light Organ of the Sepiolid Squid Euprymna scolopes Berry.

    Science.gov (United States)

    Montgomery, M K; McFall-Ngai, M

    1993-06-01

    The sepiolid squid Euprymna scolopes maintains luminous bacterial symbionts of the species Vibrio fischeri in a bilobed light organ partially embedded in the ventral surface of the ink sac. Anatomical and ultrastructural observations of the light organ during embryogenesis indicate that the organ begins development as a paired proliferation of the mesoderm of the hindgut-ink sac complex. Three-dimensional reconstruction of the incipient light organ of a newly hatched juvenile revealed the presence of three pairs of sacculate crypts, each crypt joined to a pore on the surface of the light organ by a ciliated duct. The crypts, which become populated with bacterial symbionts within hours after the juvenile hatches, appear to result from sequential paired invaginations of the surface epithelium of the hindgut-ink sac complex during embryogenesis. A pair of anterior and a pair of posterior ciliated epithelial appendages, which may facilitate infection of the incipient light organ with symbiotic bacteria, develop by extension and growth of the surface epithelium. The ink sac and reflector develop dorsal to the crypts and together function to direct luminescence ventrally. These two accessory tissues are present at the time of hatching, although changes in their overall structure accompany growth and maturation of the light organ. A third accessory tissue, the muscle-derived lens, appears during post-hatch maturation of the light organ.

  16. [Conseqquences of dorso-ventral and anterior-posterior reversion of early neurula lateral mesoblast on development of urogenital system in common toad, Bufo bufo. (Amphibia anura)].

    Science.gov (United States)

    Hakim, J; Gipouloux, J D

    1975-10-27

    At early neurula stage of the toad, cranio-caudal and dorso-ventral reversal of lateral mesoblast is performed. The genito-urinary system is therefore missing after this intervention. The three following factors of the formation of this system anlage are anlyzed: lateral mesoderm competence, stimulative activites of dorso-caudal endoblast on the one hand, of chordo-mesoderm on the other hand.

  17. Development, organization, and remodeling of phoronid muscles from embryo to metamorphosis (Lophotrochozoa: Phoronida).

    Science.gov (United States)

    Temereva, Elena N; Tsitrin, Eugeni B

    2013-04-24

    The phoronid larva, which is called the actinotrocha, is one of the most remarkable planktotrophic larval types among marine invertebrates. Actinotrochs live in plankton for relatively long periods and undergo catastrophic metamorphosis, in which some parts of the larval body are consumed by the juvenile. The development and organization of the muscular system has never been described in detail for actinotrochs and for other stages in the phoronid life cycle. In Phoronopsis harmeri, muscular elements of the preoral lobe and the collar originate in the mid-gastrula stage from mesodermal cells, which have immigrated from the anterior wall of the archenteron. Muscles of the trunk originate from posterior mesoderm together with the trunk coelom. The organization of the muscular system in phoronid larvae of different species is very complex and consists of 14 groups of muscles. The telotroch constrictor, which holds the telotroch in the larval body during metamorphosis, is described for the first time. This unusual muscle is formed by apical myofilaments of the epidermal cells. Most larval muscles are formed by cells with cross-striated organization of myofibrils. During metamorphosis, most elements of the larval muscular system degenerate, but some of them remain and are integrated into the juvenile musculature. Early steps of phoronid myogenesis reflect the peculiarities of the actinotroch larva: the muscle of the preoral lobe is the first muscle to appear, and it is important for food capture. The larval muscular system is organized in differently in different phoronid larvae, but always exhibits a complexity that probably results from the long pelagic life, planktotrophy, and catastrophic metamorphosis. Degeneration of the larval muscular system during phoronid metamorphosis occurs in two ways, i.e., by complete or by incomplete destruction of larval muscular elements. The organization and remodeling of the muscular system in phoronids exhibits the combination of

  18. Development, organization, and remodeling of phoronid muscles from embryo to metamorphosis (Lophotrochozoa: Phoronida)

    Science.gov (United States)

    2013-01-01

    Background The phoronid larva, which is called the actinotrocha, is one of the most remarkable planktotrophic larval types among marine invertebrates. Actinotrochs live in plankton for relatively long periods and undergo catastrophic metamorphosis, in which some parts of the larval body are consumed by the juvenile. The development and organization of the muscular system has never been described in detail for actinotrochs and for other stages in the phoronid life cycle. Results In Phoronopsis harmeri, muscular elements of the preoral lobe and the collar originate in the mid-gastrula stage from mesodermal cells, which have immigrated from the anterior wall of the archenteron. Muscles of the trunk originate from posterior mesoderm together with the trunk coelom. The organization of the muscular system in phoronid larvae of different species is very complex and consists of 14 groups of muscles. The telotroch constrictor, which holds the telotroch in the larval body during metamorphosis, is described for the first time. This unusual muscle is formed by apical myofilaments of the epidermal cells. Most larval muscles are formed by cells with cross-striated organization of myofibrils. During metamorphosis, most elements of the larval muscular system degenerate, but some of them remain and are integrated into the juvenile musculature. Conclusion Early steps of phoronid myogenesis reflect the peculiarities of the actinotroch larva: the muscle of the preoral lobe is the first muscle to appear, and it is important for food capture. The larval muscular system is organized in differently in different phoronid larvae, but always exhibits a complexity that probably results from the long pelagic life, planktotrophy, and catastrophic metamorphosis. Degeneration of the larval muscular system during phoronid metamorphosis occurs in two ways, i.e., by complete or by incomplete destruction of larval muscular elements. The organization and remodeling of the muscular system in phoronids

  19. LHX2 Mediates the FGF-to-SHH Regulatory Loop during Limb Development

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    Billy A. Watson

    2018-06-01

    Full Text Available During limb development, fibroblast growth factors (Fgfs govern proximal–distal outgrowth and patterning. FGFs also synchronize developmental patterning between the proximal–distal and anterior–posterior axes by maintaining Sonic hedgehog (Shh expression in cells of the zone of polarizing activity (ZPA in the distal posterior mesoderm. Shh, in turn, maintains Fgfs in the apical ectodermal ridge (AER that caps the distal tip of the limb bud. Crosstalk between Fgf and Shh signaling is critical for patterned limb development, but the mechanisms underlying this feedback loop are not well-characterized. Implantation of Fgf beads in the proximal posterior limb bud can maintain SHH expression in the former ZPA domain (evident 3 h after application, while prolonged exposure (24 h can induce SHH outside of this domain. Although temporally and spatially disparate, comparative analysis of transcriptome data from these different populations accentuated genes involved in SHH regulation. Comparative analysis identified 25 candidates common to both treatments, with eight linked to SHH expression or function. Furthermore, we demonstrated that LHX2, a LIM Homeodomain transcription factor, is an intermediate in the FGF-mediated regulation of SHH. Our data suggest that LHX2 acts as a competency factor maintaining distal posterior SHH expression subjacent to the AER.

  20. Hepatocyte growth factor is crucial for development of the carapace in turtles.

    Science.gov (United States)

    Kawashima-Ohya, Yoshie; Narita, Yuichi; Nagashima, Hiroshi; Usuda, Ryo; Kuratani, Shigeru

    2011-01-01

    Turtles are characterized by their shell, composed of a dorsal carapace and a ventral plastron. The carapace first appears as the turtle-specific carapacial ridge (CR) on the lateral aspect of the embryonic flank. Accompanying the acquisition of the shell, unlike in other amniotes, hypaxial muscles in turtle embryos appear as thin threads of fibrous tissue. To understand carapacial evolution from the perspective of muscle development, we compared the development of the muscle plate, the anlage of hypaxial muscles, between the Chinese soft-shelled turtle, Pelodiscus sinensis, and chicken embryos. We found that the ventrolateral lip (VLL) of the thoracic dermomyotome of P. sinensis delaminates early and produces sparse muscle plate in the lateral body wall. Expression patterns of the regulatory genes for myotome differentiation, such as Myf5, myogenin, Pax3, and Pax7 have been conserved among amniotes, including turtles. However, in P. sinensis embryos, the gene hepatocyte growth factor (HGF), encoding a regulatory factor for delamination of the dermomyotomal VLL, was uniquely expressed in sclerotome and the lateral body wall at the interlimb level. Implantation of COS-7 cells expressing a HGF antagonist into the turtle embryo inhibited CR formation. We conclude that the de novo expression of HGF in the turtle mesoderm would have played an innovative role resulting in the acquisition of the turtle-specific body plan. © 2011 Wiley Periodicals, Inc.

  1. A review of hedgehog signaling in cranial bone development

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    Angel ePan

    2013-04-01

    Full Text Available During craniofacial development, the Hedgehog (HH signaling pathway is essential for mesodermal tissue patterning and differentiation. The Hedgehog family consists of three protein ligands: Sonic Hedgehog (SHH, Indian Hedgehog (IHH, and Desert Hedgehog (DHH, of which two are expressed in the craniofacial complex (IHH and SHH. Dysregulations in HH signaling are well documented to result in a wide range of craniofacial abnormalities, including holoprosencephaly, hypotelorism, and cleft lip/palate. Furthermore, mutations in HH effectors, co-receptors, and ciliary proteins result in skeletal and craniofacial deformities. Cranial suture morphogenesis is a delicate developmental process that requires control of cell commitment, proliferation and differentiation. This review focuses on both what is known and what remains unknown regarding HH signaling in cranial suture morphogenesis and intramembranous ossification. As demonstrated from murine studies, expression of both SHH and IHH is critical to the formation and fusion of the cranial sutures and calvarial ossification. SHH expression has been observed in the cranial suture mesenchyme and its precise function is not fully defined, although some postulate SHH to delay cranial suture fusion. IHH expression is mainly found on the osteogenic fronts of the calvarial bones, and functions to induce cell proliferation and differentiation. Unfortunately, neonatal lethality of deficient mice precludes a detailed examination of their postnatal calvarial phenotype. In summary, a number of basic questions are yet to be answered regarding domains of expression, developmental role, and functional overlap of HH morphogens in the calvaria. Nevertheless, SHH and IHH ligands are integral to cranial suture development and regulation of calvarial ossification. When HH signaling goes awry, the resultant suite of morphologic abnormalities highlights the important roles of HH signaling in cranial development.

  2. Structural requirements for PACSIN/Syndapin operation during zebrafish embryonic notochord development.

    Science.gov (United States)

    Edeling, Melissa A; Sanker, Subramaniam; Shima, Takaki; Umasankar, P K; Höning, Stefan; Kim, Hye Y; Davidson, Lance A; Watkins, Simon C; Tsang, Michael; Owen, David J; Traub, Linton M

    2009-12-03

    PACSIN/Syndapin proteins are membrane-active scaffolds that participate in endocytosis. The structure of the Drosophila Syndapin N-terminal EFC domain reveals a crescent shaped antiparallel dimer with a high affinity for phosphoinositides and a unique membrane-inserting prong upon the concave surface. Combined structural, biochemical and reverse genetic approaches in zebrafish define an important role for Syndapin orthologue, Pacsin3, in the early formation of the notochord during embryonic development. In pacsin3-morphant embryos, midline convergence of notochord precursors is defective as axial mesodermal cells fail to polarize, migrate and differentiate properly. The pacsin3 morphant phenotype of a stunted body axis and contorted trunk is rescued by ectopic expression of Drosophila Syndapin, and depends critically on both the prong that protrudes from the surface of the bowed Syndapin EFC domain and the ability of the antiparallel dimer to bind tightly to phosphoinositides. Our data confirm linkage between directional migration, endocytosis and cell specification during embryonic morphogenesis and highlight a key role for Pacsin3 in this coupling in the notochord.

  3. Structural requirements for PACSIN/Syndapin operation during zebrafish embryonic notochord development.

    Directory of Open Access Journals (Sweden)

    Melissa A Edeling

    2009-12-01

    Full Text Available PACSIN/Syndapin proteins are membrane-active scaffolds that participate in endocytosis. The structure of the Drosophila Syndapin N-terminal EFC domain reveals a crescent shaped antiparallel dimer with a high affinity for phosphoinositides and a unique membrane-inserting prong upon the concave surface. Combined structural, biochemical and reverse genetic approaches in zebrafish define an important role for Syndapin orthologue, Pacsin3, in the early formation of the notochord during embryonic development. In pacsin3-morphant embryos, midline convergence of notochord precursors is defective as axial mesodermal cells fail to polarize, migrate and differentiate properly. The pacsin3 morphant phenotype of a stunted body axis and contorted trunk is rescued by ectopic expression of Drosophila Syndapin, and depends critically on both the prong that protrudes from the surface of the bowed Syndapin EFC domain and the ability of the antiparallel dimer to bind tightly to phosphoinositides. Our data confirm linkage between directional migration, endocytosis and cell specification during embryonic morphogenesis and highlight a key role for Pacsin3 in this coupling in the notochord.

  4. Germ layers, the neural crest and emergent organization in development and evolution.

    Science.gov (United States)

    Hall, Brian K

    2018-04-10

    Discovered in chick embryos by Wilhelm His in 1868 and named the neural crest by Arthur Milnes Marshall in 1879, the neural crest cells that arise from the neural folds have since been shown to differentiate into almost two dozen vertebrate cell types and to have played major roles in the evolution of such vertebrate features as bone, jaws, teeth, visceral (pharyngeal) arches, and sense organs. I discuss the discovery that ectodermal neural crest gave rise to mesenchyme and the controversy generated by that finding; the germ layer theory maintained that only mesoderm could give rise to mesenchyme. A second topic of discussion is germ layers (including the neural crest) as emergent levels of organization in animal development and evolution that facilitated major developmental and evolutionary change. The third topic is gene networks, gene co-option, and the evolution of gene-signaling pathways as key to developmental and evolutionary transitions associated with the origin and evolution of the neural crest and neural crest cells. © 2018 Wiley Periodicals, Inc.

  5. Tbx2/3 is an essential mediator within the Brachyury gene network during Ciona notochord development.

    Science.gov (United States)

    José-Edwards, Diana S; Oda-Ishii, Izumi; Nibu, Yutaka; Di Gregorio, Anna

    2013-06-01

    T-box genes are potent regulators of mesoderm development in many metazoans. In chordate embryos, the T-box transcription factor Brachyury (Bra) is required for specification and differentiation of the notochord. In some chordates, including the ascidian Ciona, members of the Tbx2 subfamily of T-box genes are also expressed in this tissue; however, their regulatory relationships with Bra and their contributions to the development of the notochord remain uncharacterized. We determined that the notochord expression of Ciona Tbx2/3 (Ci-Tbx2/3) requires Ci-Bra, and identified a Ci-Tbx2/3 notochord CRM that necessitates multiple Ci-Bra binding sites for its activity. Expression of mutant forms of Ci-Tbx2/3 in the developing notochord revealed a role for this transcription factor primarily in convergent extension. Through microarray screens, we uncovered numerous Ci-Tbx2/3 targets, some of which overlap with known Ci-Bra-downstream notochord genes. Among the Ci-Tbx2/3 notochord targets are evolutionarily conserved genes, including caspases, lineage-specific genes, such as Noto4, and newly identified genes, such as MLKL. This work sheds light on a large section of the notochord regulatory circuitry controlled by T-box factors, and reveals new components of the complement of genes required for the proper formation of this structure.

  6. Insulin redirects differentiation from cardiogenic mesoderm and endoderm to neuroectoderm in differentiating human embryonic stem cells.

    NARCIS (Netherlands)

    Freund, C.M.A.H.; Ward-van Oostwaard, D.; Monshouwer-Kloots, J.; van den Brink, S.; van Rooijen, M.A.; Xu, X.; Zweigerdt, R.; Mummery, C.L.; Passier, R.

    2008-01-01

    Human embryonic stem cells (hESC) can proliferate indefinitely while retaining the capacity to form derivatives of all three germ layers. We have reported previously that hESC differentiate into cardiomyocytes when cocultured with a visceral endoderm-like cell line (END-2). Insulin/insulin-like

  7. Limb patterning genes and heterochronic development of the emu wing bud

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    Craig A. Smith

    2016-12-01

    Full Text Available Abstract Background The forelimb of the flightless emu is a vestigial structure, with greatly reduced wing elements and digit loss. To explore the molecular and cellular mechanisms associated with the evolution of vestigial wings and loss of flight in the emu, key limb patterning genes were examined in developing embryos. Methods Limb development was compared in emu versus chicken embryos. Immunostaining for cell proliferation markers was used to analyze growth of the emu forelimb and hindlimb buds. Expression patterns of limb patterning genes were studied, using whole-mount in situ hybridization (for mRNA localization and RNA-seq (for mRNA expression levels. Results The forelimb of the emu embryo showed heterochronic development compared to that in the chicken, with the forelimb bud being retarded in its development. Early outgrowth of the emu forelimb bud is characterized by a lower level of cell proliferation compared the hindlimb bud, as assessed by PH3 immunostaining. In contrast, there were no obvious differences in apoptosis in forelimb versus hindlimb buds (cleaved caspase 3 staining. Most key patterning genes were expressed in emu forelimb buds similarly to that observed in the chicken, but with smaller expression domains. However, expression of Sonic Hedgehog (Shh mRNA, which is central to anterior–posterior axis development, was delayed in the emu forelimb bud relative to other patterning genes. Regulators of Shh expression, Gli3 and HoxD13, also showed altered expression levels in the emu forelimb bud. Conclusions These data reveal heterochronic but otherwise normal expression of most patterning genes in the emu vestigial forelimb. Delayed Shh expression may be related to the small and vestigial structure of the emu forelimb bud. However, the genetic mechanism driving retarded emu wing development is likely to rest within the forelimb field of the lateral plate mesoderm, predating the expression of patterning genes.

  8. A model of growth restraints to explain the development and evolution of tooth shapes in mammals.

    Science.gov (United States)

    Osborn, Jeffrey W

    2008-12-07

    The problem investigated here is control of the development of tooth shape. Cells at the growing soft tissue interface between the ectoderm and mesoderm in a tooth anlage are observed to buckle and fold into a template for the shape of the tooth crown. The final shape is created by enamel secreted onto the folds. The pattern in which the folds develop is generally explained as a response to the pattern in which genes are locally expressed at the interface. This congruence leaves the problem of control unanswered because it does not explain how either pattern is controlled. Obviously, cells are subject to Newton's laws of motion so that mechanical forces and constraints must ultimately cause the movements of cells during tooth morphogenesis. A computer model is used to test the hypothesis that directional resistances to growth of the epithelial part of the interface could account for the shape into which the interface folds. The model starts with a single epithelial cell whose growth is constrained by 4 constant directional resistances (anterior, posterior, medial and lateral). The constraints force the growing epithelium to buckle and fold. By entering into the model different values for these constraints the modeled epithelium is induced to buckle and fold into the different shapes associated with the evolution of a human upper molar from that of a reptilian ancestor. The patterns and sizes of cusps and the sequences in which they develop are all correctly reproduced. The model predicts the changes in the 4 directional constraints necessary to develop and evolve from one tooth shape into another. I conclude more generally expressed genes that control directional resistances to growth, not locally expressed genes, may provide the information for the shape into which a tooth develops.

  9. Occipital foramina development involves localised regulation of mesenchyme proliferation and is independent of apoptosis

    Science.gov (United States)

    Akbareian, Sophia E; Pitsillides, Andrew A; Macharia, Raymond G; McGonnell, Imelda M

    2015-01-01

    Cranial foramina are holes within the skull, formed during development, allowing entry and exit of blood vessels and nerves. Once formed they must remain open, due to the vital structures they contain, i.e. optic nerves, jugular vein, carotid artery, and other cranial nerves and blood vessels. Understanding cranial foramina development is essential as cranial malformations lead to the stenosis or complete closure of these structures, resulting in blindness, deafness, facial paralysis, raised intracranial pressure and lethality. Here we focus on describing early events in the formation of the jugular, carotid and hypoglossal cranial foramina that form in the mesoderm-derived, endochondral occipital bones at the base of the embryonic chick skull. Whole-mount skeletal staining of skulls indicates the appearance of these foramina from HH32/D7.5 onwards. Haematoxylin & eosin staining of sections shows that the intimately associated mesenchyme, neighbouring the contents of these cranial foramina, is initially very dense and gradually becomes sparser as development proceeds. Histological examination also revealed that these foramina initially contain relatively large-diameter nerves, which later become refined, and are closely associated with the blood vessel, which they also innervate within the confines of the foramina. Interestingly cranial foramina in the base of the skull contain blood vessels lacking smooth muscle actin, which suggests these blood vessels belong to glomus body structures within the foramina. The blood vessel shape also appears to dictate the overall shape of the resulting foramina. We initially hypothesised that cranial foramina development could involve targeted proliferation and local apoptosis to cause ‘mesenchymal clearing’ and the creation of cavities in a mechanism similar to joint cavitation. We find that this is not the case, and propose that a mechanism reliant upon local nerve/blood vessel-derived restriction of ossification may

  10. Wnt11b is involved in cilia-mediated symmetry breakage during Xenopus left-right development.

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    Peter Walentek

    Full Text Available Breakage of bilateral symmetry in amphibian embryos depends on the development of a ciliated epithelium at the gastrocoel roof during early neurulation. Motile cilia at the gastrocoel roof plate (GRP give rise to leftward flow of extracellular fluids. Flow is required for asymmetric gene expression and organ morphogenesis. Wnt signaling has previously been involved in two steps, Wnt/ß-catenin mediated induction of Foxj1, a regulator of motile cilia, and Wnt/planar cell polarity (PCP dependent cilia polarization to the posterior pole of cells. We have studied Wnt11b in the context of laterality determination, as this ligand was reported to activate canonical and non-canonical Wnt signaling. Wnt11b was found to be expressed in the so-called superficial mesoderm (SM, from which the GRP derives. Surprisingly, Foxj1 was only marginally affected in loss-of-function experiments, indicating that another ligand acts in this early step of laterality specification. Wnt11b was required, however, for polarization of GRP cilia and GRP morphogenesis, in line with the known function of Wnt/PCP in cilia-driven leftward flow. In addition Xnr1 and Coco expression in the lateral-most GRP cells, which sense flow and generate the first asymmetric signal, was attenuated in morphants, involving Wnt signaling in yet another process related to symmetry breakage in Xenopus.

  11. Sall4-Gli3 system in early limb progenitors is essential for the development of limb skeletal elements.

    Science.gov (United States)

    Akiyama, Ryutaro; Kawakami, Hiroko; Wong, Julia; Oishi, Isao; Nishinakamura, Ryuichi; Kawakami, Yasuhiko

    2015-04-21

    Limb skeletal elements originate from the limb progenitor cells, which undergo expansion and patterning to develop each skeletal element. Posterior-distal skeletal elements, such as the ulna/fibula and posterior digits develop in a Sonic hedgehog (Shh)-dependent manner. However, it is poorly understood how anterior-proximal elements, such as the humerus/femur, the radius/tibia and the anterior digits, are developed. Here we show that the zinc finger factors Sall4 and Gli3 cooperate for proper development of the anterior-proximal skeletal elements and also function upstream of Shh-dependent posterior skeletal element development. Conditional inactivation of Sall4 in the mesoderm before limb outgrowth caused severe defects in the anterior-proximal skeletal elements in the hindlimb. We found that Gli3 expression is reduced in Sall4 mutant hindlimbs, but not in forelimbs. This reduction caused posteriorization of nascent hindlimb buds, which is correlated with a loss of anterior digits. In proximal development, Sall4 integrates Gli3 and the Plzf-Hox system, in addition to proliferative expansion of cells in the mesenchymal core of nascent hindlimb buds. Whereas forelimbs developed normally in Sall4 mutants, further genetic analysis identified that the Sall4-Gli3 system is a common regulator of the early limb progenitor cells in both forelimbs and hindlimbs. The Sall4-Gli3 system also functions upstream of the Shh-expressing ZPA and the Fgf8-expressing AER in fore- and hindlimbs. Therefore, our study identified a critical role of the Sall4-Gli3 system at the early steps of limb development for proper development of the appendicular skeletal elements.

  12. Stage specific requirement of platelet-derived growth factor receptor-α in embryonic development.

    Directory of Open Access Journals (Sweden)

    Chen Qian

    Full Text Available Platelet-derived growth factor receptor alpha (PDGFRα is a cell-surface receptor tyrosine kinase for platelet-derived growth factors. Correct timing and level of Pdgfra expression is crucial for embryo development, and deletion of Pdgfra caused developmental defects of multiple endoderm and mesoderm derived structures, resulting in a complex phenotypes including orofacial cleft, spina bifida, rib deformities, and omphalocele in mice. However, it is not clear if deletion of Pdgfra at different embryonic stages differentially affects these structures.To address the temporal requirement of Pdgfra in embryonic development.We have deleted the Pdgfra in Pdgfra-expressing tissues at different embryonic stages in mice, examined and quantified the developmental anomalies.Current study showed that (i conditional deletion of Pdgfra at different embryonic days (between E7.5 and E10.5 resulted in orofacial cleft, spina bifida, rib cage deformities, and omphalocele, and (ii the day of Pdgfra deletion influenced the combinations, incidence and severities of these anomalies. Deletion of Pdgfra caused apoptosis of Pdgfra-expressing tissues, and developmental defects of their derivatives.Orofacial cleft, spina bifida and omphalocele are among the commonest skeletal and abdominal wall defects of newborns, but their genetic etiologies are largely unknown. The remarkable resemblance of our conditional Pdgfra knockout embryos to theses human congenital anomalies, suggesting that dysregulated PDGFRA expression could cause these anomalies in human. Future work should aim at defining (a the regulatory elements for the expression of the human PDGFRA during embryonic development, and (b if mutations / sequence variations of these regulatory elements cause these anomalies.

  13. Phenothiourea sensitizes zebrafish cranial neural crest and extraocular muscle development to changes in retinoic acid and IGF signaling.

    Directory of Open Access Journals (Sweden)

    Brenda L Bohnsack

    Full Text Available 1-Phenyl 2-thiourea (PTU is a tyrosinase inhibitor commonly used to block pigmentation and aid visualization of zebrafish development. At the standard concentration of 0.003% (200 µM, PTU inhibits melanogenesis and reportedly has minimal other effects on zebrafish embryogenesis. We found that 0.003% PTU altered retinoic acid and insulin-like growth factor (IGF regulation of neural crest and mesodermal components of craniofacial development. Reduction of retinoic acid synthesis by the pan-aldehyde dehydrogenase inhibitor diethylbenzaldehyde, only when combined with 0.003% PTU, resulted in extraocular muscle disorganization. PTU also decreased retinoic acid-induced teratogenic effects on pharyngeal arch and jaw cartilage despite morphologically normal appearing PTU-treated controls. Furthermore, 0.003% PTU in combination with inhibition of IGF signaling through either morpholino knockdown or pharmacologic inhibition of tyrosine kinase receptor phosphorylation, disrupted jaw development and extraocular muscle organization. PTU in and of itself inhibited neural crest development at higher concentrations (0.03% and had the greatest inhibitory effect when added prior to 22 hours post fertilization (hpf. Addition of 0.003% PTU between 4 and 20 hpf decreased thyroxine (T4 in thyroid follicles in the nasopharynx of 96 hpf embryos. Treatment with exogenous triiodothyronine (T3 and T4 improved, but did not completely rescue, PTU-induced neural crest defects. Thus, PTU should be used with caution when studying zebrafish embryogenesis as it alters the threshold of different signaling pathways important during craniofacial development. The effects of PTU on neural crest development are partially caused by thyroid hormone signaling.

  14. Near-field characteristics of highly non-paraxial subwavelength optical fields with hybrid states of polarization

    International Nuclear Information System (INIS)

    Chen Rui-Pin; Gao Teng-Yue; Chew Khian-Hooi; Dai Chao-Qing; Zhou Guo-Quan; He Sai-Ling

    2017-01-01

    The vectorial structure of an optical field with hybrid states of polarization (SoP) in the near-field is studied by using the angular spectrum method of an electromagnetic beam. Physical images of the longitudinal components of evanescent waves are illustrated and compared with those of the transverse components from the vectorial structure. Our results indicate that the relative weight integrated over the transverse plane of the evanescent wave depends strongly on the number of the polarization topological charges. The shapes of the intensity profiles of the longitudinal components are different from those of the transverse components, and it can be manipulated by changing the initial SoP of the field cross-section. The longitudinal component of evanescent wave dominates the near-field region. In addition, it also leads to three-dimensional shape variations of the optical field and the optical spin angular momentum flux density distributions. (paper)

  15. Cloning of zebrafish Mustn1 orthologs and their expression during early development.

    Science.gov (United States)

    Camarata, Troy; Vasilyev, Aleksandr; Hadjiargyrou, Michael

    2016-11-15

    Mustn1 is a small nuclear protein that is involved in the development and regeneration of the musculoskeletal system. Previous work established a role for Mustn1 in myogenic and chondrogenic differentiation. In addition, recent evidence suggests a potential role for Mustn1 in cilia function in zebrafish. A detailed study of Mustn1 expression has yet to be conducted in zebrafish. As such, we report herein the cloning of the zebrafish Mustn1 orthologs, mustn1a and mustn1b, and their expression during zebrafish embryonic and larval development. Results indicate a 44% nucleotide identity between the two paralogs. Phylogenetic analysis further confirmed that the Mustn1a and 1b predicted proteins were highly related to other vertebrate members of the Mustn1 protein family. Whole mount in situ hybridization revealed expression of both mustn1a and 1b at the 7-somite stage through 72hpf in structures such as Kupffer's vesicle, segmental mesoderm, head structures, and otic vesicle. Additionally, in 5day old larva, mustn1a and 1b expression is detected in the neurocranium, otic capsule, and the gut. Although both were expressed in the neurocranium, mustn1a was localized in the hypophyseal fenestra whereas mustn1b was found near the posterior basicapsular commissure. mustn1b also displayed expression in the ceratohyal and ceratobranchial elements of the pharyngeal skeleton. These expression patterns were verified temporally by q-PCR analysis. Taken together, we conclude that Mustn1 expression is conserved in vertebrates and that the variations in expression of the two zebrafish paralogs suggest different modes of molecular regulation. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. The head problem. The organizational significance of segmentation in head development.

    Science.gov (United States)

    Horder, Tim J; Presley, Robert; Slípka, Jaroslav

    2010-01-01

    This review argues for the segmental basis of chordate head organization which, like somite-based segmental organization in the trunk, takes its origin from early mesodermal development. The review builds on, and brings up to date, Goodrich's well-known scheme of head organization. It surveys recent data in support of this scheme and shows how evidence and arguments supposedly in conflict with it can be accommodated. Many of the arguments revolve around matters of methodology; the limitations of older LM, SEM (on which the concept of "somitomeres" is based) and recent molecular evidence (which has sometimes been seen as allocating the central role in head organization to the CNS and the neural crest) are highlighted and shown to explain a number of claims contrary to Goodrich's. We provide (in Part 2) a new, comparative survey of the best available evidence most directly relevant to the Goodrich Bauplan, with a special emphasis on stem chordates. The postotic region has commonly been seen as segmentally organized: the critical issues concern the preotic region. There are many reasons why Goodrich's three preotic segments may become specialized during evolution and why the underlying initial segmental organization may be overridden in later stages during embryonic development; we refer to a number of these. We conclude that the preotic segmental Bauplan is remarkably conserved and most explicitly demonstrated among stem forms, but we also suggest that the concept of the prechordal plate requires careful reexamination. Central to our overall analysis is the importance of the epigenetic nature of embryogenesis; its implications are made clear. Finally we speculate on evolutionary implications for the origin of the head and its specialized features. The review is intended to serve as a resource giving access to references to a wealth of now neglected, older data on anamniote embryology.

  17. New gene targets for glucagon-like peptide-1 during embryonic development and in undifferentiated pluripotent cells.

    Science.gov (United States)

    Sanz, Carmen; Blázquez, Enrique

    2011-09-01

    In humans, glucagon-like peptide (GLP-1) functions during adult life as an incretin hormone with anorexigenic and antidiabetogenic properties. Also, the therapeutic potential of GLP-1 in preventing the adipocyte hyperplasia associated with obesity and in bolstering the maintenance of human mesenchymal stem cell (hMSC) stores by promoting the proliferation and cytoprotection of hMSC seems to be relevant. Since these observations suggest a role for GLP-1 during developmental processes, the aim of the present work was to characterize GLP-1 in early development as well as its gene targets in mouse embryonic stem (mES) cells. Mouse embryos E6, E8, and E10.5 and pluripotent mES were used for the inmunodetection of GLP-1 and GLP-1 receptor. Quantitative real-time PCR was used to determine the expression levels of GLP-1R in several tissues from E12.5 mouse embryos. Additionally, GLP-1 gene targets were studied in mES by multiple gene expression analyses. GLP-1 and its receptors were identified in mES and during embryonic development. In pluripotent mES, GLP-1 modified the expression of endodermal, ectodermal, and mesodermal gene markers as well as sonic hedgehog, noggin, members of the fibroblast and hepatic growth factor families, and others involved in pancreatic development. Additionally, GLP-1 promoted the expression of the antiapoptotic gene bcl2 and at the same time reduced proapoptotic caspase genes. Our results indicate that apart from the effects and therapeutic benefits of GLP-1 in adulthood, it may have additional gene targets in mES cells during embryonic life. Furthermore, the pathophysiological implications of GLP-1 imbalance in adulthood may have a counterpart during development.

  18. Cardiac development in zebrafish and human embryonic stem cells is inhibited by exposure to tobacco cigarettes and e-cigarettes.

    Directory of Open Access Journals (Sweden)

    Nathan J Palpant

    Full Text Available Maternal smoking is a risk factor for low birth weight and other adverse developmental outcomes.We sought to determine the impact of standard tobacco cigarettes and e-cigarettes on heart development in vitro and in vivo.Zebrafish (Danio rerio were used to assess developmental effects in vivo and cardiac differentiation of human embryonic stem cells (hESCs was used as a model for in vitro cardiac development.In zebrafish, exposure to both types of cigarettes results in broad, dose-dependent developmental defects coupled with severe heart malformation, pericardial edema and reduced heart function. Tobacco cigarettes are more toxic than e-cigarettes at comparable nicotine concentrations. During cardiac differentiation of hESCs, tobacco smoke exposure results in a delayed transition through mesoderm. Both types of cigarettes decrease expression of cardiac transcription factors in cardiac progenitor cells, suggesting a persistent delay in differentiation. In definitive human cardiomyocytes, both e-cigarette- and tobacco cigarette-treated samples showed reduced expression of sarcomeric genes such as MLC2v and MYL6. Furthermore, tobacco cigarette-treated samples had delayed onset of beating and showed low levels and aberrant localization of N-cadherin, reduced myofilament content with significantly reduced sarcomere length, and increased expression of the immature cardiac marker smooth muscle alpha-actin.These data indicate a negative effect of both tobacco cigarettes and e-cigarettes on heart development in vitro and in vivo. Tobacco cigarettes are more toxic than E-cigarettes and exhibit a broader spectrum of cardiac developmental defects.

  19. The orphan receptor ALK7 and the Activin receptor ALK4 mediate signaling by Nodal proteins during vertebrate development

    Science.gov (United States)

    Reissmann, Eva; Jörnvall, Henrik; Blokzijl, Andries; Andersson, Olov; Chang, Chenbei; Minchiotti, Gabriella; Persico, M. Graziella; Ibáñez, Carlos F.; Brivanlou, Ali H.

    2001-01-01

    Nodal proteins have crucial roles in mesendoderm formation and left–right patterning during vertebrate development. The molecular mechanisms of signal transduction by Nodal and related ligands, however, are not fully understood. In this paper, we present biochemical and functional evidence that the orphan type I serine/threonine kinase receptor ALK7 acts as a receptor for mouse Nodal and Xenopus Nodal-related 1 (Xnr1). Receptor reconstitution experiments indicate that ALK7 collaborates with ActRIIB to confer responsiveness to Xnr1 and Nodal. Both receptors can independently bind Xnr1. In addition, Cripto, an extracellular protein genetically implicated in Nodal signaling, can independently interact with both Xnr1 and ALK7, and its expression greatly enhances the ability of ALK7 and ActRIIB to respond to Nodal ligands. The Activin receptor ALK4 is also able to mediate Nodal signaling but only in the presence of Cripto, with which it can also interact directly. A constitutively activated form of ALK7 mimics the mesendoderm-inducing activity of Xnr1 in Xenopus embryos, whereas a dominant-negative ALK7 specifically blocks the activities of Nodal and Xnr1 but has little effect on other related ligands. In contrast, a dominant-negative ALK4 blocks all mesoderm-inducing ligands tested, including Nodal, Xnr1, Xnr2, Xnr4, and Activin. In agreement with a role in Nodal signaling, ALK7 mRNA is localized to the ectodermal and organizer regions of Xenopus gastrula embryos and is expressed during early stages of mouse embryonic development. Therefore, our results indicate that both ALK4 and ALK7 can mediate signal transduction by Nodal proteins, although ALK7 appears to be a receptor more specifically dedicated to Nodal signaling. PMID:11485994

  20. Sp6 and Sp8 Transcription Factors Control AER Formation and Dorsal-Ventral Patterning in Limb Development

    Science.gov (United States)

    Haro, Endika; Delgado, Irene; Junco, Marisa; Yamada, Yoshihiko; Mansouri, Ahmed; Oberg, Kerby C.; Ros, Marian A.

    2014-01-01

    The formation and maintenance of the apical ectodermal ridge (AER) is critical for the outgrowth and patterning of the vertebrate limb. The induction of the AER is a complex process that relies on integrated interactions among the Fgf, Wnt, and Bmp signaling pathways that operate within the ectoderm and between the ectoderm and the mesoderm of the early limb bud. The transcription factors Sp6 and Sp8 are expressed in the limb ectoderm and AER during limb development. Sp6 mutant mice display a mild syndactyly phenotype while Sp8 mutants exhibit severe limb truncations. Both mutants show defects in AER maturation and in dorsal-ventral patterning. To gain further insights into the role Sp6 and Sp8 play in limb development, we have produced mice lacking both Sp6 and Sp8 activity in the limb ectoderm. Remarkably, the elimination or significant reduction in Sp6;Sp8 gene dosage leads to tetra-amelia; initial budding occurs, but neither Fgf8 nor En1 are activated. Mutants bearing a single functional allele of Sp8 (Sp6−/−;Sp8+/−) exhibit a split-hand/foot malformation phenotype with double dorsal digit tips probably due to an irregular and immature AER that is not maintained in the center of the bud and on the abnormal expansion of Wnt7a expression to the ventral ectoderm. Our data are compatible with Sp6 and Sp8 working together and in a dose-dependent manner as indispensable mediators of Wnt/βcatenin and Bmp signaling in the limb ectoderm. We suggest that the function of these factors links proximal-distal and dorsal-ventral patterning. PMID:25166858

  1. Xenopus Zic3 controls notochord and organizer development through suppression of the Wnt/β-catenin signaling pathway.

    Science.gov (United States)

    Fujimi, Takahiko J; Hatayama, Minoru; Aruga, Jun

    2012-01-15

    Zic3 controls neuroectodermal differentiation and left-right patterning in Xenopus laevis embryos. Here we demonstrate that Zic3 can suppress Wnt/β-catenin signaling and control development of the notochord and Spemann's organizer. When we overexpressed Zic3 by injecting its RNA into the dorsal marginal zone of 2-cell-stage embryos, the embryos lost mesodermal dorsal midline structures and showed reduced expression of organizer markers (Siamois and Goosecoid) and a notochord marker (Xnot). Co-injection of Siamois RNA partially rescued the reduction of Xnot expression caused by Zic3 overexpression. Because the expression of Siamois in the organizer region is controlled by Wnt/β-catenin signaling, we subsequently examined the functional interaction between Zic3 and Wnt signaling. Co-injection of Xenopus Zic RNAs and β-catenin RNA with a reporter responsive to the Wnt/β-catenin cascade indicated that Zic1, Zic2, Zic3, Zic4, and Zic5 can all suppress β-catenin-mediated transcriptional activation. In addition, co-injection of Zic3 RNA inhibited the secondary axis formation caused by ventral-side injection of β-catenin RNA in Xenopus embryos. Zic3-mediated Wnt/β-catenin signal suppression required the nuclear localization of Zic3, and involved the reduction of β-catenin nuclear transport and enhancement of β-catenin degradation. Furthermore, Zic3 co-precipitated with Tcf1 (a β-catenin co-factor) and XIC (I-mfa domain containing factor required for dorsoanterior development). The findings in this report produce a novel system for fine-tuning of Wnt/β-catenin signaling. Copyright © 2011. Published by Elsevier Inc.

  2. Yolk sac development in lizards (Lacertilia: Scincidae): New perspectives on the egg of amniotes.

    Science.gov (United States)

    Stewart, James R; Thompson, Michael B

    2017-04-01

    Embryos of oviparous reptiles develop on the surface of a large mass of yolk, which they metabolize to become relatively large hatchlings. Access to the yolk is provided by tissues growing outward from the embryo to cover the surface of the yolk. A key feature of yolk sac development is a dedicated blood vascular system to communicate with the embryo. The best known model for yolk sac development and function of oviparous amniotes is based on numerous studies of birds, primarily domestic chickens. In this model, the vascular yolk sac forms the perimeter of the large yolk mass and is lined by a specialized epithelium, which takes up, processes and transports yolk nutrients to the yolk sac blood vessels. Studies of lizard yolk sac development, dating to more than 100 years ago, report characteristics inconsistent with this model. We compared development of the yolk sac from oviposition to near hatching in embryonic series of three species of oviparous scincid lizards to consider congruence with the pattern described for birds. Our findings reinforce results of prior studies indicating that squamate reptiles mobilize and metabolize the large yolk reserves in their eggs through a process unknown in other amniotes. Development of the yolk sac of lizards differs from birds in four primary characteristics, migration of mesoderm, proliferation of endoderm, vascular development and cellular diversity within the yolk sac cavity. Notably, all of the yolk is incorporated into cells relatively early in development and endodermal cells within the yolk sac cavity align along blood vessels which course throughout the yolk sac cavity. The pattern of uptake of yolk by endodermal cells indicates that the mechanism of yolk metabolism differs between lizards and birds and that the evolution of a fundamental characteristic of embryonic nutrition diverged in these two lineages. Attributes of the yolk sac of squamates reveal the existence of phylogenetic diversity among amniote lineages

  3. Origins and Properties of Dental, Thymic, and Bone Marrow Mesenchymal Cells and Their Stem Cells

    Science.gov (United States)

    Komada, Yukiya; Yamane, Toshiyuki; Kadota, Daiji; Isono, Kana; Takakura, Nobuyuki; Hayashi, Shin-Ichi; Yamazaki, Hidetoshi

    2012-01-01

    Mesenchymal cells arise from the neural crest (NC) or mesoderm. However, it is difficult to distinguish NC-derived cells from mesoderm-derived cells. Using double-transgenic mouse systems encoding P0-Cre, Wnt1-Cre, Mesp1-Cre, and Rosa26EYFP, which enabled us to trace NC-derived or mesoderm-derived cells as YFP-expressing cells, we demonstrated for the first time that both NC-derived (P0- or Wnt1-labeled) and mesoderm-derived (Mesp1-labeled) cells contribute to the development of dental, thymic, and bone marrow (BM) mesenchyme from the fetal stage to the adult stage. Irrespective of the tissues involved, NC-derived and mesoderm-derived cells contributed mainly to perivascular cells and endothelial cells, respectively. Dental and thymic mesenchyme were composed of either NC-derived or mesoderm-derived cells, whereas half of the BM mesenchyme was composed of cells that were not derived from the NC or mesoderm. However, a colony-forming unit-fibroblast (CFU-F) assay indicated that CFU-Fs in the dental pulp, thymus, and BM were composed of NC-derived and mesoderm-derived cells. Secondary CFU-F assays were used to estimate the self-renewal potential, which showed that CFU-Fs in the teeth, thymus, and BM were entirely NC-derived cells, entirely mesoderm-derived cells, and mostly NC-derived cells, respectively. Colony formation was inhibited drastically by the addition of anti-platelet–derived growth factor receptor-β antibody, regardless of the tissue and its origin. Furthermore, dental mesenchyme expressed genes encoding critical hematopoietic factors, such as interleukin-7, stem cell factor, and cysteine-X-cysteine (CXC) chemokine ligand 12, which supports the differentiation of B lymphocytes and osteoclasts. Therefore, the mesenchymal stem cells found in these tissues had different origins, but similar properties in each organ. PMID:23185234

  4. The ctenophore genome and the evolutionary origins of neural systems

    NARCIS (Netherlands)

    Moroz, Leonid L.; Kocot, Kevin M.; Citarella, Mathew R.; Dosung, Sohn; Norekian, Tigran P.; Povolotskaya, Inna S.; Grigorenko, Anastasia P.; Dailey, Christopher; Berezikov, Eugene; Buckley, Katherine M.; Ptitsyn, Andrey; Reshetov, Denis; Mukherjee, Krishanu; Moroz, Tatiana P.; Bobkova, Yelena; Yu, Fahong; Kapitonov, Vladimir V.; Jurka, Jerzy; Bobkov, Yuri V.; Swore, Joshua J.; Girardo, David O.; Fodor, Alexander; Gusev, Fedor; Sanford, Rachel; Bruders, Rebecca; Kittler, Ellen; Mills, Claudia E.; Rast, Jonathan P.; Derelle, Romain; Solovyev, Victor V.; Kondrashov, Fyodor A.; Swalla, Billie J.; Sweedler, Jonathan V.; Rogaev, Evgeny I.; Halanych, Kenneth M.; Kohn, Andrea B.

    2014-01-01

    The origins of neural systems remain unresolved. In contrast to other basal metazoans, ctenophores (comb jellies) have both complex nervous and mesoderm-derived muscular systems. These holoplanktonic predators also have sophisticated ciliated locomotion, behaviour and distinct development. Here we

  5. Mesenchymal cells reactivate Snail1 expression to drive three-dimensional invasion programs

    DEFF Research Database (Denmark)

    Rowe, R.G.; Li, X.Y.; Hu, Y.

    2009-01-01

    Epithelial-mesenchymal transition (EMT) is required for mesodermal differentiation during development. The zinc-finger transcription factor, Snail1, can trigger EMT and is sufficient to transcriptionally reprogram epithelial cells toward a mesenchymal phenotype during neoplasia and fibrosis. Whet...

  6. Surface ultrastructural studies on the germination, penetration and conidial development of Aspergillus flavus Link:Fries infecting silkworm, Bombyx mori Linn.

    Science.gov (United States)

    Kumar, Vineet; Singh, G P; Babu, A M

    2004-01-01

    Aspergillosis is a common disease of the silkworm Bombyx mori Linn., caused by an insect mycopathogen Aspergillus flavus Link:Fries. The present study reveals the germination, penetration and conidial development of A. flavus on the larval integument of B. mori under SEM. Four different strains (NB18, KA, NB4D2 and NB7) of B. mori was surface inoculated with ca. of 1 x 10(6) conidia/ml. Each conidium germinated on the cuticle approximately 6 h after inoculation, forming a humpy or suctorial appressoria within 24 h. The hyphae which entered into haemocoel 2 day post-inoculation, grew and multiplied extensively, forming a mycelial complex, causing death of the host larva in about 4-5 days. This occurred with minimal breakdown of the internal tissues. Death of the host was followed by ramification of the fungus through the mesodermal and epidermal tissues, leading to larval mummification about 5-6 days after inoculation. Extensive fungal growths on the entire larval body followed, consisting of aerial hyphae, which developed branched conidiophores. The aerial hyphae with abundant conidiophores formed a confluent yellowish green fungal mat over the entire larval body in 6-7 days of post-inoculation. The tip of each emerging conidiophores gradually dilated and developed to become a bulbous head known as the vesicle. A large number of conidiogenous cells were produced over the entire surface of vesicle, which later developed into finger-like projections termed as sterigmata or phialides. The phialides matured within 2 days after the aerial hyphae emerged as evidenced by chains of conidia at their tips. The conidia were globose with externally roughened walls. The life cycle of the fungus on B. mori was completed in six to seven days.

  7. Identification and expression analysis of zebrafish polypeptide α-N-acetylgalactosaminyltransferase Y-subfamily genes during embryonic development.

    Science.gov (United States)

    Nakayama, Yoshiaki; Nakamura, Naosuke; Kawai, Tamiko; Kaneda, Eiichi; Takahashi, Yui; Miyake, Ayumi; Itoh, Nobuyuki; Kurosaka, Akira

    2014-09-01

    Mucin-type glycosylation is one of the most common posttranslational modifications of secretory and membrane proteins and has diverse physiological functions. The initial biosynthesis of mucin-type carbohydrates is catalyzed by UDP-GalNAc: polypeptide α-N-acetylgalactosaminyltransferases (GalNAc-Ts) encoded by GALNT genes. Among these, GalNAc-T8, -T9, -T17, and -T18 form a characteristic subfamily called "Y-subfamily" and have no or very low in vitro transferase activities when assayed with typical mucin peptides as acceptor substrates. Although the Y-subfamily isozymes have been reported to be possibly involved in various diseases, their in vivo functions have not been reported. Here, we isolated zebrafish Y-subfamily galnt genes, and determined their spatial and temporal expressions during the early development of zebrafish. Our study demonstrated that all the Y-subfamily isozymes were well conserved in zebrafish with GalNAc-T18 having two orthologs, galnt18a and galnt18b, and with the other three isozymes each having a corresponding ortholog, galnt8, galnt9, and galnt17. The galnt8 was expressed in the cephalic mesoderm and hatching gland during early developmental stages, and differently expressed in the head, somatic muscles, and liver in the later stages. The other three orthologs also exhibited the characteristic expression patterns, although their expressions were generally strong in the nervous systems. In addition to the expression in the brain, galnt17 and galnt18a were expressed in the somitic muscles, and galnt18a and galnt18b in the notochord. These expression patterns may contribute to the functional analysis of the Y-subfamily, whose physiological roles still remain to be elucidated. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. TRPP2-dependent Ca2+ signaling in dorso-lateral mesoderm is required for kidney field establishment in Xenopus.

    Science.gov (United States)

    Futel, Mélinée; Leclerc, Catherine; Le Bouffant, Ronan; Buisson, Isabelle; Néant, Isabelle; Umbhauer, Muriel; Moreau, Marc; Riou, Jean-François

    2015-03-01

    In Xenopus laevis embryos, kidney field specification is dependent on retinoic acid (RA) and coincides with a dramatic increase of Ca(2+) transients, but the role of Ca(2+) signaling in the kidney field is unknown. Here, we identify TRPP2, a member of the transient receptor potential (TRP) superfamily of channel proteins encoded by the pkd2 gene, as a central component of Ca(2+) signaling in the kidney field. TRPP2 is strongly expressed at the plasma membrane where it might regulate extracellular Ca(2+) entry. Knockdown of pkd2 in the kidney field results in the downregulation of pax8, but not of other kidney field genes (lhx1, osr1 and osr2). We further show that inhibition of Ca(2+) signaling with an inducible Ca(2+) chelator also causes downregulation of pax8, and that pkd2 knockdown results in a severe inhibition of Ca(2+) transients in kidney field explants. Finally, we show that disruption of RA results both in an inhibition of intracellular Ca(2+) signaling and of TRPP2 incorporation into the plasma membrane of kidney field cells. We propose that TRPP2-dependent Ca(2+) signaling is a key component of pax8 regulation in the kidney field downstream of RA-mediated non-transcriptional control of TRPP2. © 2015. Published by The Company of Biologists Ltd.

  9. Extracellular matrix dynamics during vertebrate axis formation.

    Science.gov (United States)

    Czirók, András; Rongish, Brenda J; Little, Charles D

    2004-04-01

    The first evidence for the dynamics of in vivo extracellular matrix (ECM) pattern formation during embryogenesis is presented below. Fibrillin 2 filaments were tracked for 12 h throughout the avian intraembryonic mesoderm using automated light microscopy and algorithms of our design. The data show that these ECM filaments have a reproducible morphogenic destiny that is characterized by directed transport. Fibrillin 2 particles initially deposited in the segmental plate mesoderm are translocated along an unexpected trajectory where they eventually polymerize into an intricate scaffold of cables parallel to the anterior-posterior axis. The cables coalesce near the midline before the appearance of the next-formed somite. Moreover, the ECM filaments define global tissue movements with high precision because the filaments act as passive motion tracers. Quantification of individual and collective filament "behaviors" establish fate maps, trajectories, and velocities. These data reveal a caudally propagating traveling wave pattern in the morphogenetic movements of early axis formation. We conjecture that within vertebrate embryos, long-range mechanical tension fields are coupled to both large-scale patterning and local organization of the ECM. Thus, physical forces or stress fields are essential requirements for executing an emergent developmental pattern-in this case, paraxial fibrillin cable assembly.

  10. Image distortion due to refraction by planar surfaces

    International Nuclear Information System (INIS)

    Arizaga, R; Cap, N; Rabal, H; Trivi, M

    2010-01-01

    The term 'apparent depth' is commonly treated in textbooks as an issue easily understandable from the point of view of paraxial optical geometrical optics. Nevertheless, everyday life tells us that most of the time the observation of objects immersed in water is made under a great range of visual angles where the paraxial approximation is not valid. Here we developed a non-paraxial treatment to calculate the position and shape of the image of objects immersed in liquids of different refractive indices. The approach was focused on the parametric positions of the images of a single point at different viewing angles. Then we calculated how the image of an extended object is distorted. By using the Matlab software, it is possible to visualize the images for different geometrical conditions. We also include the analysis for refractive index with negative values as is the case of metamaterials.

  11. Image distortion due to refraction by planar surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Arizaga, R; Cap, N; Rabal, H; Trivi, M [Centro de Investigaciones Opticas (CONICET La Plata-CIC) and OPTIMO Dto de Ciencias Basicas, Fac. de Ingenieria UNLP, PO Box 3, 1897 Gonnet, La Plata (Argentina)

    2010-01-15

    The term 'apparent depth' is commonly treated in textbooks as an issue easily understandable from the point of view of paraxial optical geometrical optics. Nevertheless, everyday life tells us that most of the time the observation of objects immersed in water is made under a great range of visual angles where the paraxial approximation is not valid. Here we developed a non-paraxial treatment to calculate the position and shape of the image of objects immersed in liquids of different refractive indices. The approach was focused on the parametric positions of the images of a single point at different viewing angles. Then we calculated how the image of an extended object is distorted. By using the Matlab software, it is possible to visualize the images for different geometrical conditions. We also include the analysis for refractive index with negative values as is the case of metamaterials.

  12. Evaluation of Geometrical Modulation Transfer Function in Optical Lens System

    Directory of Open Access Journals (Sweden)

    Cheng-Mu Tsai

    2015-01-01

    Full Text Available This paper presents ray tracing algorithms to evaluate the geometrical modulation transfer function (GMTF of optical lens system. There are two kinds of ray tracings methods that can be applied to help simulate the point spread function (PSF in the image plane, for example, paraxial optics and real ray tracings. The paraxial optics ray tracing is used to calculate the first-order properties such as the effective focal length (EFL and the entrance pupil position through less cost of computation. However, the PSF could have a large tolerance by only using paraxial optics ray tracing for simulation. Some formulas for real ray tracing are applied in the sagittal and tangential line spread function (LSF. The algorithms are developed to demonstrate the simulation of LSF. Finally, the GMTF is evaluated after the fast Fourier transform (FFT of the LSF.

  13. Expression of transmembrane carbonic anhydrases, CAIX and CAXII, in human development

    Directory of Open Access Journals (Sweden)

    Lerman Michael I

    2009-03-01

    Full Text Available Abstract Background Transmembrane CAIX and CAXII are members of the alpha carbonic anhydrase (CA family. They play a crucial role in differentiation, proliferation, and pH regulation. Expression of CAIX and CAXII proteins in tumor tissues is primarily induced by hypoxia and this is particularly true for CAIX, which is regulated by the transcription factor, hypoxia inducible factor-1 (HIF-1. Their distributions in normal adult human tissues are restricted to highly specialized cells that are not always hypoxic. The human fetus exists in a relatively hypoxic environment. We examined expression of CAIX, CAXII and HIF-1α in the developing human fetus and postnatal tissues to determine whether expression of CAIX and CAXII is exclusively regulated by HIF-1. Results The co-localization of CAIX and HIF-1α was limited to certain cell types in embryonic and early fetal tissues. Those cells comprised the primitive mesenchyma or involved chondrogenesis and skin development. Transient CAIX expression was limited to immature tissues of mesodermal origin and the skin and ependymal cells. The only tissues that persistently expressed CAIX protein were coelomic epithelium (mesothelium and its remnants, the epithelium of the stomach and biliary tree, glands and crypt cells of duodenum and small intestine, and the cells located at those sites previously identified as harboring adult stem cells in, for example, the skin and large intestine. In many instances co-localization of CAIX and HIF-1α was not evident. CAXII expression is restricted to cells involved in secretion and water absorption such as parietal cells of the stomach, acinar cells of the salivary glands and pancreas, epithelium of the large intestine, and renal tubules. Co-localization of CAXII with CAIX or HIF-1α was not observed. Conclusion The study has showed that: 1 HIF-1α and CAIX expression co- localized in many, but not all, of the embryonic and early fetal tissues; 2 There is no evidence of

  14. Evolution and Development of the Inner Ear Efferent System: Transforming a Motor Neuron Population to Connect to the Most Unusual Motor Protein via Ancient Nicotinic Receptors

    Directory of Open Access Journals (Sweden)

    Bernd Fritzsch

    2017-04-01

    Full Text Available All craniate chordates have inner ears with hair cells that receive input from the brain by cholinergic centrifugal fibers, the so-called inner ear efferents (IEEs. Comparative data suggest that IEEs derive from facial branchial motor (FBM neurons that project to the inner ear instead of facial muscles. Developmental data showed that IEEs develop adjacent to FBMs and segregation from IEEs might depend on few transcription factors uniquely associated with IEEs. Like other cholinergic terminals in the peripheral nervous system (PNS, efferent terminals signal on hair cells through nicotinic acetylcholine channels, likely composed out of alpha 9 and alpha 10 units (Chrna9, Chrna10. Consistent with the evolutionary ancestry of IEEs is the even more conserved ancestry of Chrna9 and 10. The evolutionary appearance of IEEs may reflect access of FBMs to a novel target, possibly related to displacement or loss of mesoderm-derived muscle fibers by the ectoderm-derived ear vesicle. Experimental transplantations mimicking this possible aspect of ear evolution showed that different motor neurons of the spinal cord or brainstem form cholinergic synapses on hair cells when ears replace somites or eyes. Transplantation provides experimental evidence in support of the evolutionary switch of FBM neurons to become IEEs. Mammals uniquely evolved a prestin related motor system to cause shape changes in outer hair cells regulated by the IEEs. In summary, an ancient motor neuron population drives in craniates via signaling through highly conserved Chrna receptors a uniquely derived cellular contractility system that is essential for hearing in mammals.

  15. Brain Development

    Science.gov (United States)

    ... Become a Member Home Early Development & Well-Being Brain Development A child’s brain undergoes an amazing period of development from birth ... neural connections each second. The development of the brain is influenced by many factors, including a child’s ...

  16. Developmental Mechanism of Limb Field Specification along the Anterior–Posterior Axis during Vertebrate Evolution

    Directory of Open Access Journals (Sweden)

    Mikiko Tanaka

    2016-05-01

    Full Text Available In gnathostomes, limb buds arise from the lateral plate mesoderm at discrete positions along the body axis. Specification of these limb-forming fields can be subdivided into several steps. The lateral plate mesoderm is regionalized into the anterior lateral plate mesoderm (ALPM; cardiac mesoderm and the posterior lateral plate mesoderm (PLPM. Subsequently, Hox genes appear in a nested fashion in the PLPM and provide positional information along the body axis. The lateral plate mesoderm then splits into the somatic and splanchnic layers. In the somatic layer of the PLPM, the expression of limb initiation genes appears in the limb-forming region, leading to limb bud initiation. Furthermore, past and current work in limbless amphioxus and lampreys suggests that evolutionary changes in developmental programs occurred during the acquisition of paired fins during vertebrate evolution. This review presents these recent advances and discusses the mechanisms of limb field specification during development and evolution, with a focus on the role of Hox genes in this process.

  17. Employees development

    OpenAIRE

    Kilijánová, Radka

    2010-01-01

    Employees development is one of the main activities of human resources management. It is connected with other activites, such as training of employees, career development and performance management. In the recent days there is an increased importance put on employees development, although the current economic crisis still has some consequences, such as reduced development budget of many organizations. The thesis mentiones employees development in the first place in the context of management o...

  18. Anomalias ósseas congênitas em Sotalia guianensis (Mammalia, Cetacea, Delphinidae da costa centro-norte do Estado do Rio de Janeiro Congenital bone defects in Guiana dolphin, Sotalia guianensis (Mammalia, Cetacea, Delphinidae in the northcentral coast of Rio de Janeiro State, Brazil

    Directory of Open Access Journals (Sweden)

    Maíra Laeta

    2010-06-01

    vertebrae preserved. The series has 75% of immature animals and all skeletons displayed a minimum of taphonomic changes. Two categories of congenital anomalies were diagnosed, both related to the development of the paraxial mesoderm. The seventh cervical vertebra (C7 was the only affected; the cervical ribs and the cleft neural arches were present in 15 (75% of the individuals, three (15% of which had both anomalies. Nine (45% individuals had unilateral or bilateral cervical ribs, and nine (45% individuals had cleft neural arches; the contiguous vertebrae were normal in every case. The frequency of these anomalies was higher in that Rio de Janeiro series than in other Sotalia series previously reported in the Brazilian literature for Amazonas, Ceará and Santa Catarina States. The present Sotalia series here described comes from a very limited coastal region probably representing a local population. The cervical ribs are genetically defined and may be concentrated because of a condition of close biological proximity among the animals; the cleft arch could also be determined by environmental factors, to be investigated in the future.

  19. Multimobile Development

    CERN Document Server

    Baxter-Reynolds, Matthew

    2010-01-01

    You've developed a killer app for one mobile device - now it's time to maximize your intellectual investment and develop for the full spectrum of mobile platforms and devices. With Multimobile Development, you'll learn how to quickly retool between the iPhone and Android platforms and broaden the interest and audience of your app, without working with burdensome and error-prone compatibility layers and toolkits. Multimobile Development takes you, the developer, through the same mobile software development project on both platforms, learning the differences between and the relative strengths an

  20. Representing Development

    DEFF Research Database (Denmark)

    Representing Development presents the different social representations that have formed the idea of development in Western thinking over the past three centuries. Offering an acute perspective on the current state of developmental science and providing constructive insights into future pathways, ...

  1. Economic Development

    Science.gov (United States)

    Recruitment Events Community Commitment Giving Campaigns, Drives Economic Development Employee Funded : Environmental Documents, Reports LANL Home Calendar Search Contacts Community » Economic Development LANL 75th logo Economic Development Los Alamos National Laboratory is committed to investing and partnering in

  2. Modularizing development

    DEFF Research Database (Denmark)

    Müller, Anders Riel; Doucette, Jamie

    a deeper and wider understanding of Korea’s development experience with the hope that Korea’s past can offer lessons for developing countries in search of sustainable and broad‐based development" (KSP 2011). To do so, the KSP provides users with a modularized set of policy narratives that represent Korea...

  3. Pattern and polarity in the development and evolution of the gnathostome jaw: both conservation and heterotopy in the branchial arches of the shark, Scyliorhinus canicula.

    Science.gov (United States)

    Compagnucci, Claudia; Debiais-Thibaud, Melanie; Coolen, Marion; Fish, Jennifer; Griffin, John N; Bertocchini, Federica; Minoux, Maryline; Rijli, Filippo M; Borday-Birraux, Véronique; Casane, Didier; Mazan, Sylvie; Depew, Michael J

    2013-05-15

    The acquisition of jaws constitutes a landmark event in vertebrate evolution, one that in large part potentiated their success and diversification. Jaw development and patterning involves an intricate spatiotemporal series of reciprocal inductive and responsive interactions between the cephalic epithelia and the cranial neural crest (CNC) and cephalic mesodermal mesenchyme. The coordinated regulation of these interactions is critical for both the ontogenetic registration of the jaws and the evolutionary elaboration of variable jaw morphologies and designs. Current models of jaw development and evolution have been built on molecular and cellular evidence gathered mostly in amniotes such as mice, chicks and humans, and augmented by a much smaller body of work on the zebrafish. These have been partnered by essential work attempting to understand the origins of jaws that has focused on the jawless lamprey. Chondrichthyans (cartilaginous fish) are the most distant group to amniotes within extant gnathostomes, and comprise the crucial clade uniting amniotes and agnathans; yet despite their critical phylogenetic position, evidence of the molecular and cellular underpinnings of jaw development in chondrichthyans is still lacking. Recent advances in genome and molecular developmental biology of the lesser spotted dogfish shark, Scyliorhinus canicula, make it ideal for the molecular study of chondrichthyan jaw development. Here, following the 'Hinge and Caps' model of jaw development, we have investigated evidence of heterotopic (relative changes in position) and heterochronic (relative changes in timing) shifts in gene expression, relative to amniotes, in the jaw primordia of S. canicula embryos. We demonstrate the presence of clear proximo-distal polarity in gene expression patterns in the shark embryo, thus establishing a baseline molecular baüplan for branchial arch-derived jaw development and further validating the utility of the 'Hinge and Caps' model in comparative

  4. Developing Collaborative Product Development Capabilities

    DEFF Research Database (Denmark)

    Mahnke, Volker; Tran, Yen

    2012-01-01

    innovation strategies’. Our analyses suggest that developing such collaboration capabilities benefits from the search for complementary practices, the combination of learning styles, and the development of weak and strong ties. Results also underscore the crucial importance of co-evolution of multi......Collaborative product development capabilities support a company’s product innovation activities. In the context of the fast fashion sector, this paper examines the development of the product development capabilities (PDC) that align product development capabilities in a dual innovation context......, one, slow paced, where the firm is well established and the other, fast paced, which represents a new competitive arena in which the company competes. To understand the process associated with collaborative capability development, we studied three Scandinavian fashion companies pursuing ‘dual...

  5. Numerical Development

    Science.gov (United States)

    Siegler, Robert S.; Braithwaite, David W.

    2016-01-01

    In this review, we attempt to integrate two crucial aspects of numerical development: learning the magnitudes of individual numbers and learning arithmetic. Numerical magnitude development involves gaining increasingly precise knowledge of increasing ranges and types of numbers: from non-symbolic to small symbolic numbers, from smaller to larger…

  6. Child Development

    Science.gov (United States)

    ... developmental conditions. More Child Development Basics Early Brain Development Developmental Screening Screening for Professionals Positive Parenting Tips Infants (0-1 year) Toddlers (1-2 years) Toddlers (2-3 years) Preschoolers (3-5 years) Middle Childhood (6-8 years) Middle Childhood (9-11 years) ...

  7. Stamen development

    NARCIS (Netherlands)

    Keijzer, C.J.

    1986-01-01

    In this thesis the development of the stamen is investigated, using structural and histochemical observations, micromanipulation and in-vitro culture.

    Formation and exposure of pollen are the two main goals of the developing stamen. The main processes of the pollen formation were

  8. Africa Development

    African Journals Online (AJOL)

    Africa Development is the quarterly bilingual journal of CODESRIA. It is a social science journal whose major focus is on issues which are central to the development of society. Its principal objective is to provide a forum for the exchange of ideas among African scholars from a variety of intellectual persuasions and various ...

  9. Photocathode development

    International Nuclear Information System (INIS)

    Hinrichs, C.K.; Estrella, R.M.

    1979-01-01

    A research program for the development of photocathodes for use in streak image tubes is described. This is one task in the development of a high-resolution, high-speed x-ray streak camera system whose primary application is for diagnostics in underground nuclear testing. There are three objectives in the photocathode development program: (1) the development of new x-ray photocathodes compatible with the requirements of streak tubes; (2) the development of the capability to process high-quality visible light photocathodes as well as x-ray photocathodes; and (3) the design and construction of a transfer photocathode system. Design and construction of all the major components of the transfer photocathode system were completed. Assembly should be completed in early FY 80

  10. Developing markets?

    DEFF Research Database (Denmark)

    Figueiredo, Bernardo; Chelekis, Jessica; DeBerry-Spence, Benet

    2015-01-01

    acknowledging complex, systemic interdependencies between markets, marketing, and society. Based on a critical review of the meaning of development and an interrogation of various developmental discourses, the authors develop a conceptual framework that brings together issues of development, wellbeing......, and social inequalities. We suggest that these issues are better understooda nd addressed when examined via grounded investigations of the role of markets in shaping the management of resources, consumer agency, power inequalities and ethics. The use of markets as units of analysis may lead to further cross...

  11. Developing Friendships:

    DEFF Research Database (Denmark)

    Hansen, Annette Skovsted

    2005-01-01

    reparations and - to a lesser degree - ODA as repentance for war crimes. Officials and other invlved parties often coded their interventions of development projects in language of friendship, whereby they expressed a Japanese desire to change the image of Japan from enemy to friend. In the wake of WWII...... of these programs in development assistance initiatives reflected Japanese attempts to redefine themselves as friends rather than enemies in the minds of Asian neighbors. Other donors also used friendship vocabulary in relation to their development assistance and I will apply a comparative perspective in order...

  12. Organisational development.

    Science.gov (United States)

    2017-03-30

    The aim of the NHS Improvement national leadership and improvement strategy is to encourage leaders at all levels to develop leadership skills in their staff and themselves. It focuses on fostering compassionate, collaborative and inclusive leadership.

  13. Personality Development

    Directory of Open Access Journals (Sweden)

    Osman Ozdemir

    2012-12-01

    Full Text Available Personality is the integration of characteristics acquired or brought by birth which separate the individual from others. Personality involves aspects of the individual's mental, emotional, social, and physical features in continuum. Several theories were suggested to explain developmental processes of personality. Each theory concentrates on one feature of human development as the focal point, then integrates with other areas of development in general. Most theories assume that childhood, especially up to 5-6 years, has essential influence on development of personality. The interaction between genetic and environmental factors reveals a unique personality along growth and developmental process. It could be said that individual who does not have any conflict between his/her basic needs and society's, has well-developed and psychologically healthy personality.

  14. Toddler Development

    Science.gov (United States)

    ... is exciting to watch your toddler learn new skills. The normal development of children aged 1-3 includes several areas: Gross motor - walking, running, climbing Fine motor - feeding themselves, drawing Sensory - seeing, hearing, tasting, ...

  15. Untenable development

    International Nuclear Information System (INIS)

    Coimbra, Guilhermina Lavoz

    1995-01-01

    The author analyses the energy - the role of law and environmental rights for sustainable development - from a critical point of view that is in accordance with internationally accepted jurisprudence. (author). 12 refs

  16. Toddler development

    Science.gov (United States)

    ... a secure place. Keep toddlers away from the kitchen with a safety gate. Place them in a ... development. In: Marcdante KJ, Kliegman RM, eds. Nelson Essentials of Pediatrics . 7th ed. Elsevier Saunders; 2015:chap ...

  17. Site development

    International Nuclear Information System (INIS)

    Noack, J.

    1975-01-01

    The subject of this paper is a general view over all necessary considerations to develop the site after it has been chosen and before starting with the construction of a nuclear power plant. (orig./RW) [de

  18. Professional development

    International Nuclear Information System (INIS)

    McAndrew-Benavidas, E.

    2007-01-01

    This presentation outlines the functions of the North American Young Generation in Nuclear. Activities of the organization include professional development, recruiting, retention, public outreach, leadership, networking, workforce issues, mentoring and communications

  19. Adolescent development

    Science.gov (United States)

    ... to: Understand abstract ideas. These include grasping higher math concepts, and developing moral philosophies, including rights and ... of safe play and how to approach more advanced activities. Young people need to be very aware ...

  20. Toddler development.

    Science.gov (United States)

    Colson, E R; Dworkin, P H

    1997-08-01

    The toddler years are ones of exciting and challenging changes in cognitive, affective, and physical growth. Physical growth is particularly remarkable for the child's increasing skills and ability to navigate the environment. Affective development is marked by the push for autonomy and independence and the highly visible nature of the child's temperament or behavioral style. The toddler also enters the wonderful years of imagination and pretend play. Perhaps most noteworthy is the child's dramatic increase in ability to communicate with others through speech and language, as evidence of the progression to symbolic thinking. The dynamic changes in children's development during the toddler years have important implications for child health supervision. Familiarity with toddler development will enable the pediatrician to monitor children's development effectively and to address common, stage-related behaviors with families during anticipatory guidance.

  1. Recent Developments

    CERN Multimedia

    Lankford, A J

    Progress has proceeded rapidly on many parallel developments throughout the Trigger, Data Acquisition, and Detector Controls Project. As design has proceeded on the component TDAQ/DCS systems and subsystems, significant integration tests have been performed. Late last year and early this year, high level trigger and data acquisition developments were brought together in what we called the Phase 1 integrated prototype. During the same period, work was started on integrating the Detector Control System (DCS) with the Online Software that will be used to control, configure, and monitor ATLAS. In addition, integration tests between components of the Level 1 Trigger (LVL1) and Dataflow systems have been performed. The Phase 1 integrated prototype involved integrating the prototype level 2 trigger system (LVL2) developed by the LVL2 Pilot Project with the prototype data acquisition system and one of the Event Filter prototypes developed by the DAQ/EF -1 Prototype project. The integrated prototype included a VME Re...

  2. Process development

    Energy Technology Data Exchange (ETDEWEB)

    Schuegerl, K

    1984-01-01

    The item 'process development' comprises the production of acetonic/butonal with C. acetobylicum and the yeasting of potato waste. The target is to increase productivity by taking the following measures - optimation of media, on-line process analysis, analysis of reaction, mathematic modelling and identification of parameters, process simulation, development of a state estimator with the help of the on-line process analysis and the model, optimization and adaptive control.

  3. Instrumentation development

    International Nuclear Information System (INIS)

    Anon.

    1976-01-01

    Areas being investigated for instrumentation improvement during low-level pollution monitoring include laser opto-acoustic spectroscopy, x-ray fluorescence spectroscopy, optical fluorescence spectroscopy, liquid crystal gas detectors, advanced forms of atomic absorption spectroscopy, electro-analytical chemistry, and mass spectroscopy. Emphasis is also directed toward development of physical methods, as opposed to conventional chemical analysis techniques for monitoring these trace amounts of pollution related to energy development and utilization

  4. Future development

    International Nuclear Information System (INIS)

    Zavitz, J.; Hetherington, C.

    1997-01-01

    Issues regarding future development by oil and gas companies in Canada's Arctic and the Beaufort Sea were discussed. It was suggested in the Berger report that Northern development should be under the control of the people whose lives and economy are being changed. Aboriginal people are now much more sophisticated politically, and have a better understanding of what is involved. Most of them would like the financial benefits from development, but the development would have to be on their terms. Most people involved with Arctic oil exploration feel that there is enough oil in the Arctic to warrant production. (Reserves in the Beaufort Sea are estimated at two billion barrels of good quality oil). If development were to continue, there exist two methods of transportation to move the oil to market. Gulf, Imperial Oil and Panarctic favour the use of pipelines, whereas Dome Petroleum Ltd. favours the use of ice-breaking tankers. In each case the favored option seems to depend upon the location of the company's leases, the capital and operating costs, and the potential environmental impacts. Undoubtedly, any future development will be guided by the scientific information and technical expertise of oil industry pioneers of the 1960s and the 1970s, and the wisdom gained from the experiences of the many participants whose views and insights are recorded in this book

  5. Site development

    International Nuclear Information System (INIS)

    Gaynor, R.K.

    1989-01-01

    Development of a low-level radioactive waste land disposal facility is little different than any industrial development of similar scope. Consideration must be made for normal business and operations management, security, facility maintenance, traffic control and necessary amenities for personnel. The item specific to the low-level waste site is the handling of radioactive waste materials and the regulatory and environmental protection procedures that must be planned for and accomodated in the site design and development. Each of these elements and the facility as a whole must be designed to be compatible with local land use plans, available transportation and support services, and the social and economic goals of the local community. Plans should also be made for quality control and orderly construction. This chapter deals with those aspects of the facility, its design and construction which are integral parts to the overall performance of the site

  6. Divine development

    DEFF Research Database (Denmark)

    Agarwala, Rina

    2015-01-01

    position in the world system and support poverty alleviation efforts within a neoliberal development framework. Indian-American Muslims draw from their poor status in India to overturn economic inequities within India by shifting India's development rhetoric from identity to class. Collective religious......This article examines how Indian Americans’ religious organizations send not only financial remittances to India, but also social remittances that shape development ideologies. Comparing Indian-American Hindu and Muslim organizations, I find both groups draw from their socioeconomic experiences...... in India and use their position as elite immigrants in the United States to identify and empower their respective religious constituencies in India and overturn different social relations (not just religious practices). Hindu Americans draw from their majority status in India to overturn India's lower...

  7. Diagnostic development

    International Nuclear Information System (INIS)

    Barnett, C.F.; Brisson, D.A.; Greco, S.E.

    1978-01-01

    During the past year the far-infrared or submillimeter diagnostic research program resulted in three major developments: (1) an optically pumped 0.385-μm D 2 O-laser oscillator-amplifier system was operated at a power level of 1 MW with a line width of less than 50 MHz; (2) a conical Pyrex submillimeter laser beam dump with a retention efficiency greater than 10 4 was developed for the ion temperature Thompson scattering experiment; and (3) a new diagnostic technique was developed that makes use of the Faraday rotation of a modulated submillimeter laser beam to determine plasma current profile. Measurements of the asymmetric distortion of the H/sub α/ (6563 A) spectral line profile show that the effective toroidal drift velocity, dv/sub two vertical bars i/dT/sub i/, may be used as an indicator of plasma quality and as a complement to other ion temperature diagnostics

  8. Development economics

    International Nuclear Information System (INIS)

    Roebuck, F.

    1992-01-01

    This paper discusses term development economics which refers to the economic evaluation of investment opportunities that occur after the discovery well is drilled and completed. with specific regard to the techniques used and the economic yardsticks available for investment decisions. Three potential situations are considered in this paper: the incorporation of development wells into the outcomes of the original exploration project, mutually exclusive or alternative investment opportunities, and the installation of improved or enhanced recovery projects during or at the end of the primary producing life of a property

  9. Diverting Developments

    DEFF Research Database (Denmark)

    Taudal Poulsen, René

    2013-01-01

    developments in the two industries have diverted after 1970. All the large and medium-sized Danish shipyards have ceased, whereas several equipment suppliers have endured and some have built up strong positions within their respective fields. Focusing on corporate strategies in shipbuilding and marine...... equipment manufacturing, this article examines the diverting developments of the two industries and asks what has caused this divergence?......Over the last couple of decades, the shipbuilding and marine equipment industries in Denmark and elsewhere in Europe have been exposed to strong competition from new and rapidly expanding maritime nations in Asia. In the 1970s, Denmark had a stronghold in both industries, which have been closely...

  10. Interorganizational Development.

    Science.gov (United States)

    Schermerhorn, John R., Jr.

    1979-01-01

    Interorganizational development is the application of social science knowledge to the creation of planned, systematic and mutually beneficial cooperative relationships between otherwise autonomous organizations. This paper introduces the concept as a means of focusing attention on key action and research issues associated with interorganizational…

  11. Leadership Development

    OpenAIRE

    Oana Simona Hudea

    2014-01-01

    This paper aims at rendering the main characteristics distinguishing leaders from common individuals, as well as from managers, while identifying the progressive steps and the key elements needed for leader development. Learning how to lead oneself is a prerequisite for leading others, but without continuous training, coaching or mentoring, and above all, without effective experience, individuals will never get to become real leaders.

  12. New Developments

    Science.gov (United States)

    Lohmander, Maelis Karlson; Vandenbroeck, Michel; Pirard, Florence; Peeters, Jan; Alvestad, Marit

    2009-01-01

    New developments and challenges regarding early childhood education (ECE) policy and practice in Norway and in the Flemish and French communities in Belgium are presented in this issue. There are clear differences between the countries when comparing systems they have chosen for ECE. In Belgium, supervision and responsibilities for education,…

  13. Developing Globalization

    DEFF Research Database (Denmark)

    Hansen, Annette Skovsted

    2017-01-01

    This chapter is the first qualitative micro case study of one aspect of globalization: personal networks as a concrete outcome of development assistance spending. The empirical findings related in this paper present circumstantial evidence that Japanese foreign aid has contributed to globalization...

  14. Infrastructure Development

    DEFF Research Database (Denmark)

    Williams, Idongesit

    2012-01-01

    access and service of telecommunications/ICTs have been stalled. This paper throws light on a possible Public Private Partnership framework as a development path that will enable affordable network technologies to be deployed in rural areas at a cost that will translate to what the rural dweller...

  15. Process development

    International Nuclear Information System (INIS)

    Zapata G, G.

    1989-01-01

    Process development: The paper describes the organization and laboratory facilities of the group working on radioactive ore processing studies. Contains a review of the carried research and the plans for the next future. A list of the published reports is also presented

  16. Contraceptive Development.

    Science.gov (United States)

    Troen, Philip; And Others

    This report provides an overview of research activities and needs in the area of contraceptive development. In a review of the present state, discussions are offered on the effectiveness and drawbacks of oral contraceptives, intrauterine devices, barrier methods, natural family planning, and sterilization. Methods of contraception that are in the…

  17. Dairy development

    NARCIS (Netherlands)

    Leegwater, P.; Hoorweg, J.C.

    2000-01-01

    The growth of the dairy sector as it has occurred in Kilifi and Malindi Districts is one of the few examples of successful agricultural development in the coastal region in the past decades. Between 1985 and 1997 dairy cattle have more than doubled in number. Three livestock systems are described:

  18. Instrumentation development

    International Nuclear Information System (INIS)

    Ubbes, W.F.; Yow, J.L. Jr.

    1988-01-01

    Instrumentation is developed for the Civilian Radioactive Waste Management Program to meet several different (and sometimes conflicting) objectives. This paper addresses instrumentation development for data needs that are related either directly or indirectly to a repository site, but does not touch on instrumentation for work with waste forms or other materials. Consequently, this implies a relatively large scale for the measurements, and an in situ setting for instrument performance. In this context, instruments are needed for site characterization to define phenomena, develop models, and obtain parameter values, and for later design and performance confirmation testing in the constructed repository. The former set of applications is more immediate, and is driven by the needs of program design and performance assessment activities. A host of general technical and nontechnical issues have arisen to challenge instrumentation development. Instruments can be classed into geomechanical, geohydrologic, or other specialty categories, but these issues cut across artificial classifications. These issues are outlined. Despite this imposing list of issues, several case histories are cited to evaluate progress in the area

  19. Leadership Development

    Science.gov (United States)

    Mallon, Melissa

    2017-01-01

    This issue's column focuses on online tools and resources available for leadership development of academic, public services staff. The resources are not targeted solely to professional librarians, but rather to all levels of library staff engaged with the public. In addition to inspirational and coaching videos, reviewers recommend resource guides…

  20. Sustainable development

    International Nuclear Information System (INIS)

    Boiteux, M.

    2004-01-01

    Marcel Boiteux evokes the results of the work on the sustainable development by the Academie des Sciences Morales et Politiques. This is a vast political programme with the goal of allowing all humanity to live well in growing unity while protecting the environment and favouring economic growth. (author)

  1. Sustainable Development

    African Journals Online (AJOL)

    Tsegai Berhane Ghebretekle

    Ethiopia is selected as a case study in light of its pace in economic growth ... Interrogating the Economy-First Paradigm in 'Sustainable Development' … 65 .... agreement, since such effective global cooperation on climate change ultimately ..... and foster innovation; reduce inequality within and among countries; make cities.

  2. Engendering Development

    OpenAIRE

    Monsod, Solita C.

    1994-01-01

    This article discusses the productive and reproductive roles Filipino women perform and assesses their contributions to human development. It also examines the reality of their marginalization from the country’s social, economic and political life. It then suggests on measures by which women can be empowered to achieve the goals of gender equality and equity.

  3. Polarization developments

    International Nuclear Information System (INIS)

    Prescott, C.Y.

    1993-07-01

    Recent developments in laser-driven photoemission sources of polarized electrons have made prospects for highly polarized electron beams in a future linear collider very promising. This talk discusses the experiences with the SLC polarized electron source, the recent progress with research into gallium arsenide and strained gallium arsenide as a photocathode material, and the suitability of these cathode materials for a future linear collider based on the parameters of the several linear collider designs that exist

  4. EOS developments

    Science.gov (United States)

    Sindrilaru, Elvin A.; Peters, Andreas J.; Adde, Geoffray M.; Duellmann, Dirk

    2017-10-01

    CERN has been developing and operating EOS as a disk storage solution successfully for over 6 years. The CERN deployment provides 135 PB and stores 1.2 billion replicas distributed over two computer centres. Deployment includes four LHC instances, a shared instance for smaller experiments and since last year an instance for individual user data as well. The user instance represents the backbone of the CERNBOX service for file sharing. New use cases like synchronisation and sharing, the planned migration to reduce AFS usage at CERN and the continuous growth has brought EOS to new challenges. Recent developments include the integration and evaluation of various technologies to do the transition from a single active in-memory namespace to a scale-out implementation distributed over many meta-data servers. The new architecture aims to separate the data from the application logic and user interface code, thus providing flexibility and scalability to the namespace component. Another important goal is to provide EOS as a CERN-wide mounted filesystem with strong authentication making it a single storage repository accessible via various services and front- ends (/eos initiative). This required new developments in the security infrastructure of the EOS FUSE implementation. Furthermore, there were a series of improvements targeting the end-user experience like tighter consistency and latency optimisations. In collaboration with Seagate as Openlab partner, EOS has a complete integration of OpenKinetic object drive cluster as a high-throughput, high-availability, low-cost storage solution. This contribution will discuss these three main development projects and present new performance metrics.

  5. Bone development

    DEFF Research Database (Denmark)

    Tatara, M.R.; Tygesen, Malin Plumhoff; Sawa-Wojtanowicz, B.

    2007-01-01

    The objective of this study was to determine the long-term effect of alpha-ketoglutarate (AKG) administration during early neonatal life on skeletal development and function, with emphasis on bone exposed to regular stress and used to serve for systemic changes monitoring, the rib. Shropshire ram.......01). Furthermore, AKG administration induced significantly higher bone mineral density of the cortical bone by 7.1% (P

  6. Leadership Development

    Directory of Open Access Journals (Sweden)

    Oana Simona Hudea

    2014-12-01

    Full Text Available This paper aims at rendering the main characteristics distinguishing leaders from common individuals, as well as from managers, while identifying the progressive steps and the key elements needed for leader development. Learning how to lead oneself is a prerequisite for leading others, but without continuous training, coaching or mentoring, and above all, without effective experience, individuals will never get to become real leaders.

  7. Professional development

    Science.gov (United States)

    Yoon, Jin Hee; Hartline, Beverly Karplus; Milner-Bolotin, Marina

    2013-03-01

    The three sessions of the professional development workshop series were each designed for a different audience. The purpose of the first session was to help mid-career physicists aspire for and achieve leadership roles. The second session brought together students, postdoctoral fellows, and early-career physicists to help them plan their career goals and navigate the steps important to launching a successful career. The final session sought to increase awareness of the results of physics education research, and how to use them to help students-especially women-learn physics better. The presentations and discussions were valuable for both female and male physicists.

  8. Energy development

    Science.gov (United States)

    Lovich, Jeffrey E.; Jones, L.L.C.; Lovich, R. L.; Halama, K.J.

    2016-01-01

    Large areas of the desert southwest are currently developed or being evaluated for construction of utility-scale renewable energy projects. These projects include numerous solar and wind energy facilities some of which will be massive. Unfortunately, peer-reviewed scientific publications are not yet available to evaluate the potential effects of solar-based utility-scale renewable energy development (USRED) on any species of wildlife, including amphibians and reptiles (herpetofauna). Scientific publications on the effects of wind-based USRED and operation (USREDO) are focused almost exclusively on flying wildlife including birds and bats. To the best of our knowledge the only publications on the effects of wind-based USREDO on herpetofauna are three publications on desert tortoise ecology at a wind energy facility near Palm Springs, California. Those studies suggested that not all effects of USREDO were detrimental in the short-term. However, additional research is required to determine if wind energy operation is compatible with conservation of this long-lived species over longer periods of time.

  9. Accelerator development

    International Nuclear Information System (INIS)

    Anon.

    1975-01-01

    Because the use of accelerated heavy ions would provide many opportunities for new and important studies in nuclear physics and nuclear chemistry, as well as other disciplines, both the Chemistry and Physics Divisions are supporting the development of a heavy-ion accelerator. The design of greatest current interest includes a tandem accelerator with a terminal voltage of approximately 25 MV injecting into a linear accelerator with rf superconducting resonators. This combined accelerator facility would be capable of accelerating ions of masses ranging over the entire periodic table to an energy corresponding to approximately 10 MeV/nucleon. This approach, as compared to other concepts, has the advantages of lower construction costs, lower operating power, 100 percent duty factor, and high beam quality (good energy resolution, good timing resolution, small beam size, and small beam divergence). The included sections describe the concept of the proposed heavy-ion accelerator, and the development program aiming at: (1) investigation of the individual questions concerning the superconducting accelerating resonators; (2) construction and testing of prototype accelerator systems; and (3) search for economical solutions to engineering problems. (U.S.)

  10. Biofilm Development

    DEFF Research Database (Denmark)

    Tolker-Nielsen, Tim

    2015-01-01

    During the past decade we have gained much knowledge about the molecular mechanisms that are involved in initiation and termination of biofilm formation. In many bacteria, these processes appear to occur in response to specific environmental cues and result in, respectively, induction or terminat......During the past decade we have gained much knowledge about the molecular mechanisms that are involved in initiation and termination of biofilm formation. In many bacteria, these processes appear to occur in response to specific environmental cues and result in, respectively, induction...... or termination of biofilm matrix production via the second messenger molecule c-di-GMP. In between initiation and termination of biofilm formation we have defined specific biofilm stages, but the currently available evidence suggests that these transitions are mainly governed by adaptive responses......, and not by specific genetic programs. It appears that biofilm formation can occur through multiple pathways and that the spatial structure of the biofilms is species dependent as well as dependent on environmental conditions. Bacterial subpopulations, e.g., motile and nonmotile subpopulations, can develop...

  11. Introduction: translocal development, development corridors and development chains.

    NARCIS (Netherlands)

    Zoomers, E.B.; Westen, A.C.M. van

    2011-01-01

    This paper offers an introduction to this Special Issue of International Development Planning Review. It uses the concepts of translocal development, development corridors and development chains to secure a better grasp of what development means in the context of globalisation and how ‘local

  12. Prune belly syndrome associated with cloacal anomaly, patent urachal remnant, and omphalocele in a female infant.

    Science.gov (United States)

    Giuliani, Stefano; Vendryes, Christopher; Malhotra, Ajay; Shaul, Donald B; Anselmo, Dean M

    2010-11-01

    Prune belly syndrome (PBS), megacystis-microcolon-intestinal hypoperistalsis (MMIH), and omphalocele-exstrophy of the bladder-imperforate anus-spine abnormalities complex (OEIS) are rare congenital malformations of the newborn that lead to incomplete formation of the gastrointestinal and genitourinary tract systems. To date, incomplete mesodermal development is identified as the cause for all these complex genetic syndromes even if the etiology is still unknown. We present an original case sharing characteristics common to PBS, MMIH, and OEIS complex, without a clear inclination toward any particular one. This case hints toward a common pathway in the creation of the 3 syndromes. We hypothesize that they are a spectrum of malformations based on the time frame when the mesoderm fails to create a normal interaction between infraumbilical mesoderm, urorectal septum, lumbosacral somites in the formation of the abdominal wall and the genitourinary and lower gastrointestinal tracts. Published by Elsevier Inc.

  13. The zebrafish tailbud contains two independent populations of midline progenitor cells that maintain long-term germ layer plasticity and differentiate in response to local signaling cues

    Science.gov (United States)

    Row, Richard H.; Tsotras, Steve R.; Goto, Hana; Martin, Benjamin L.

    2016-01-01

    Vertebrate body axis formation depends on a population of bipotential neuromesodermal cells along the posterior wall of the tailbud that make a germ layer decision after gastrulation to form spinal cord and mesoderm. Despite exhibiting germ layer plasticity, these cells never give rise to midline tissues of the notochord, floor plate and dorsal endoderm, raising the question of whether midline tissues also arise from basal posterior progenitors after gastrulation. We show in zebrafish that local posterior signals specify germ layer fate in two basal tailbud midline progenitor populations. Wnt signaling induces notochord within a population of notochord/floor plate bipotential cells through negative transcriptional regulation of sox2. Notch signaling, required for hypochord induction during gastrulation, continues to act in the tailbud to specify hypochord from a notochord/hypochord bipotential cell population. Our results lend strong support to a continuous allocation model of midline tissue formation in zebrafish, and provide an embryological basis for zebrafish and mouse bifurcated notochord phenotypes as well as the rare human congenital split notochord syndrome. We demonstrate developmental equivalency between the tailbud progenitor cell populations. Midline progenitors can be transfated from notochord to somite fate after gastrulation by ectopic expression of msgn1, a master regulator of paraxial mesoderm fate, or if transplanted into the bipotential progenitors that normally give rise to somites. Our results indicate that the entire non-epidermal posterior body is derived from discrete, basal tailbud cell populations. These cells remain receptive to extracellular cues after gastrulation and continue to make basic germ layer decisions. PMID:26674311

  14. Leading and Managing Continuing Professional Development: Developing People, Developing Schools

    Science.gov (United States)

    Earley, Peter; Bubb, Sara

    2004-01-01

    This book has been written for those who lead and manage continuing professional development (CPD). Continuing professional development co-coordinators hold a key role and one that needs to be developed further in many schools. This book is intended to help people think more deeply about the professional development and training of staff--all…

  15. Rural Community Development: Bedrock for National Development ...

    African Journals Online (AJOL)

    This paper advocates that community development is the bedrock for national development. For any meaningful development to take place, whether national or global development must have its building blocks or firm-root in rural development. However, the rural communities are characterized by isolation from ideas and ...

  16. Sustainable Development: The Challenge for Community Development.

    Science.gov (United States)

    Gamble, Dorothy N.; Weil, Marie O.

    1997-01-01

    Five areas of inquiry shape the sustainable development movement: environmental movement, women's movement, overpopulation concerns, critique of development models, and new indicators of social progress. Community development workers are challenged to prepare local development projects within a sustainable development framework. (SK)

  17. Sustainable development in a developing economy: Challenges ...

    African Journals Online (AJOL)

    USER

    2013-08-21

    Aug 21, 2013 ... towards environmental management in Nigeria which is a fast developing economy. The basic ... almost every developing country in which it is grown ..... perspective of Development in Formal and Integrated Management of.

  18. A requirement for FGF signalling in the formation of primitive streak-like intermediates from primitive ectoderm in culture.

    Directory of Open Access Journals (Sweden)

    Zhiqiang Zheng

    Full Text Available BACKGROUND: Embryonic stem (ES cells hold considerable promise as a source of cells with therapeutic potential, including cells that can be used for drug screening and in cell replacement therapies. Differentiation of ES cells into the somatic lineages is a regulated process; before the promise of these cells can be realised robust and rational methods for directing differentiation into normal, functional and safe cells need to be developed. Previous in vivo studies have implicated fibroblast growth factor (FGF signalling in lineage specification from pluripotent cells. Although FGF signalling has been suggested as essential for specification of mesoderm and endoderm in vivo and in culture, the exact role of this pathway remains unclear. METHODOLOGY/PRINCIPAL FINDINGS: Using a culture model based on early primitive ectoderm-like (EPL cells we have investigated the role of FGF signalling in the specification of mesoderm. We were unable to demonstrate any mesoderm inductive capability associated with FGF1, 4 or 8 signalling, even when the factors were present at high concentrations, nor any enhancement in mesoderm formation induced by exogenous BMP4. Furthermore, there was no evidence of alteration of mesoderm sub-type formed with addition of FGF1, 4 or 8. Inhibition of endogenous FGF signalling, however, prevented mesoderm and favoured neural differentiation, suggesting FGF signalling was required but not sufficient for the differentiation of primitive ectoderm into primitive streak-like intermediates. The maintenance of ES cell/early epiblast pluripotent marker expression was also observed in cultures when FGF signalling was inhibited. CONCLUSIONS/SIGNIFICANCE: FGF signalling has been shown to be required for the differentiation of primitive ectoderm to neurectoderm. This, coupled with our observations, suggest FGF signalling is required for differentiation of the primitive ectoderm into the germ lineages at gastrulation.

  19. Expression of Id2 in the Second Heart Field and Cardiac Defects in Id2 Knock-Out Mice

    NARCIS (Netherlands)

    Jongbloed, M. R. M.; Vicente-Steijn, R.; Douglas, Y. L.; Wisse, L. J.; Mori, K.; Yokota, Y.; Bartelings, M. M.; Schalij, M. J.; Mahtab, E. A.; Poelmann, R. E.; Gittenberger-De Groot, A. C.

    2011-01-01

    The inhibitor of differentiation Id2 is expressed in mesoderm of the second heart field, which contributes myocardial and mesenchymal cells to the primary heart tube. The role of Id2 in cardiac development is insufficiently known. Heart development was studied in sequential developmental stages in

  20. Developed-developing country partnerships: Benefits to developed countries?

    Directory of Open Access Journals (Sweden)

    Syed Shamsuzzoha B

    2012-06-01

    Full Text Available Abstract Developing countries can generate effective solutions for today’s global health challenges. This paper reviews relevant literature to construct the case for international cooperation, and in particular, developed-developing country partnerships. Standard database and web-based searches were conducted for publications in English between 1990 and 2010. Studies containing full or partial data relating to international cooperation between developed and developing countries were retained for further analysis. Of 227 articles retained through initial screening, 65 were included in the final analysis. The results were two-fold: some articles pointed to intangible benefits accrued by developed country partners, but the majority of information pointed to developing country innovations that can potentially inform health systems in developed countries. This information spanned all six WHO health system components. Ten key health areas where developed countries have the most to learn from the developing world were identified and include, rural health service delivery; skills substitution; decentralisation of management; creative problem-solving; education in communicable disease control; innovation in mobile phone use; low technology simulation training; local product manufacture; health financing; and social entrepreneurship. While there are no guarantees that innovations from developing country experiences can effectively transfer to developed countries, combined developed-developing country learning processes can potentially generate effective solutions for global health systems. However, the global pool of knowledge in this area is virgin and further work needs to be undertaken to advance understanding of health innovation diffusion. Even more urgently, a standardized method for reporting partnership benefits is needed—this is perhaps the single most immediate need in planning for, and realizing, the full potential of international

  1. Developed-developing country partnerships: benefits to developed countries?

    Science.gov (United States)

    Syed, Shamsuzzoha B; Dadwal, Viva; Rutter, Paul; Storr, Julie; Hightower, Joyce D; Gooden, Rachel; Carlet, Jean; Bagheri Nejad, Sepideh; Kelley, Edward T; Donaldson, Liam; Pittet, Didier

    2012-06-18

    Developing countries can generate effective solutions for today's global health challenges. This paper reviews relevant literature to construct the case for international cooperation, and in particular, developed-developing country partnerships. Standard database and web-based searches were conducted for publications in English between 1990 and 2010. Studies containing full or partial data relating to international cooperation between developed and developing countries were retained for further analysis. Of 227 articles retained through initial screening, 65 were included in the final analysis. The results were two-fold: some articles pointed to intangible benefits accrued by developed country partners, but the majority of information pointed to developing country innovations that can potentially inform health systems in developed countries. This information spanned all six WHO health system components. Ten key health areas where developed countries have the most to learn from the developing world were identified and include, rural health service delivery; skills substitution; decentralisation of management; creative problem-solving; education in communicable disease control; innovation in mobile phone use; low technology simulation training; local product manufacture; health financing; and social entrepreneurship. While there are no guarantees that innovations from developing country experiences can effectively transfer to developed countries, combined developed-developing country learning processes can potentially generate effective solutions for global health systems. However, the global pool of knowledge in this area is virgin and further work needs to be undertaken to advance understanding of health innovation diffusion. Even more urgently, a standardized method for reporting partnership benefits is needed--this is perhaps the single most immediate need in planning for, and realizing, the full potential of international cooperation between developed and

  2. App Development Paradigms for Instructional Developers

    Science.gov (United States)

    Luterbach, Kenneth J.; Hubbell, Kenneth R.

    2015-01-01

    To create instructional apps for desktop, laptop and mobile devices, developers must select a development tool. Tool selection is critical and complicated by the large number and variety of app development tools. One important criterion to consider is the type of development environment, which may primarily be visual or symbolic. Those distinct…

  3. Entrepreneurial Intentions in Developing and Developed Countries

    Science.gov (United States)

    Iakovleva, Tatiana; Kolvereid, Lars; Stephan, Ute

    2011-01-01

    Purpose: This study proposes to use the Theory of Planned Behaviour to predict entrepreneurial intentions among students in five developing and nine developed countries. The purpose is to investigate whether entrepreneurial intention and its antecedents differ between developing and developed countries, and to test the theory in the two groups of…

  4. Open Data for Development | IDRC - International Development ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    The Open Data for Development (OD4D) program brings together a network of ... other open data initiatives to ensure they benefit people in developing countries. ... that benefits everyone, empowering women and achieving gender equality, ...

  5. Drug discovery and developments in developing countries ...

    African Journals Online (AJOL)

    the major burden being in developing countries. Many of ... The driving force for drug discovery and development by pharmaceutical firms ... world and particularly in the third world countries ..... GFHR (2000) Global Forum for Health Research:.

  6. Development | Page 25 | IDRC - International Development ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Theoretical Perspectives on Gender and Development demystifies the theory of gender ... and development theory, introduces competing theoretical frameworks, and ... Unfortunately, however, the research environment in the Middle East and ...

  7. Preceptor development. Use a staff development specialist.

    Science.gov (United States)

    Schneller, S; Hoeppner, M

    1994-01-01

    Preceptor orientation is a well identified need. Less often identified is the critical role the staff development specialist plays in the ongoing support and development of preceptors. In this article, the authors explain activities of coaching, facilitating, mentoring, and consulting. These role components are essential in the ongoing development of preceptors. This support also may help retain preceptors.

  8. Work type II first branchial cleft cyst: a rare anomaly with a classical ...

    African Journals Online (AJOL)

    such cases. The branchial apparatus starts to appear between the fourth and the fifth weeks of fetal develop- ment. The apparatus consists of five arches consisting of the mesoderm, four clefts that consist of the ectoderm and four pouches that consist of the endoderm. The first branchial pouch forms the Eustachian tube and ...

  9. Maffucci's syndrome associated with chondrosarcoma and aneurysm: case report

    International Nuclear Information System (INIS)

    Lim, Hyoung Gun; Yoo, Won Jong; Lim, Yeon Soo; Sung, Mi Sook; Chung Myung Hee; Lee, Hae Giu; Jung, So Lyung; Kim, Jea NA

    2002-01-01

    Maffucci syndrome is a rare congenital non-inherited condition characterized by multiple enchondromas and cutaneous hemangiomas. It is associated with increased risk of malignancy, including chondrosarcomas, and because of generalized mesodermal dysplasia, aneurysms can develop. We present a case of Maffucci syndrome associated with intracranial chondrosarcoma and aneurysm

  10. Maffucci's syndrome associated with chondrosarcoma and aneurysm: case report

    International Nuclear Information System (INIS)

    Lim, Hyoung Gun; Yoo, Won Jong; Lim, Yeon Soo; Sung, Mi Sook; Chung, Myung Hee; Lee, Hae Giu; Jung, So Lyung; Kim, Jae Na

    2002-01-01

    Maffucci syndrome is rare congenital non-inherited condition characterized by multiple enchondromas and cutaneous hemangiomas. It is associated with increased risk of malignancy, including chondrosarcomas, and because of generalized mesodermal dysplasia, aneurysms can develop. We present a case of maffucci syndrome associated with intracranial chondrosarcoma and aneurysm

  11. Bidirectional Fusion of the Heart-forming Fields in the Developing Chick Embryo

    Science.gov (United States)

    Moreno-Rodriguez, R.A.; Krug, E.L.; Reyes, L.; Villavicencio, L.; Mjaatvedt, C.H.; Markwald, R.R.

    2007-01-01

    It is generally thought that the early pre-tubular chick heart is formed by fusion of the anterior or cephalic limits of the paired cardiogenic fields. However, this study shows that the heart fields initially fuse at their midpoint to form a transitory “butterfly”-shaped, cardiogenic structure. Fusion then progresses bi-directionally along the longitudinal axis in both cranial and caudal directions. Using in vivo labeling, we demonstrate that cells along the ventral fusion line are highly motile, crossing future primitive segments. We found that mesoderm cells migrated cephalically from the unfused tips of the anterior/cephalic wings into the head mesenchyme in the region that has been called the secondary heart field. Perturbing the anterior/cranial fusion results in formation of a biconal heart. A theoretical role of the ventral fusion line acting as a “heart organizer” and its role in cardia bifida is discussed. PMID:16252277

  12. Influence of the neural tube/notochord complex on MyoD expression and cellular proliferation in chicken embryos

    Directory of Open Access Journals (Sweden)

    H.J. Alves

    2003-02-01

    Full Text Available Important advances have been made in understanding the genetic processes that control skeletal muscle formation. Studies conducted on quails detected a delay in the myogenic program of animals selected for high growth rates. These studies have led to the hypothesis that a delay in myogenesis would allow somitic cells to proliferate longer and consequently increase the number of embryonic myoblasts. To test this hypothesis, recently segmented somites and part of the unsegmented paraxial mesoderm were separated from the neural tube/notochord complex in HH12 chicken embryos. In situ hybridization and competitive RT-PCR revealed that MyoD transcripts, which are responsible for myoblast determination, were absent in somites separated from neural tube/notochord (1.06 and 0.06 10-3 attomol MyoD/1 attomol ß-actin for control and separated somites, respectively; P<0.01. However, reapproximation of these structures allowed MyoD to be expressed in somites. Cellular proliferation was analyzed by immunohistochemical detection of incorporated BrdU, a thymidine analogue. A smaller but not significant (P = 0.27 number of proliferating cells was observed in somites that had been separated from neural tube/notochord (27 and 18 for control and separated somites, respectively. These results confirm the influence of the axial structures on MyoD activation but do not support the hypothesis that in the absence of MyoD transcripts the cellular proliferation would be maintained for a longer period of time.

  13. Somite-Derived Retinoic Acid Regulates Zebrafish Hematopoietic Stem Cell Formation.

    Directory of Open Access Journals (Sweden)

    Laura M Pillay

    Full Text Available Hematopoietic stem cells (HSCs are multipotent progenitors that generate all vertebrate adult blood lineages. Recent analyses have highlighted the importance of somite-derived signaling factors in regulating HSC specification and emergence from dorsal aorta hemogenic endothelium. However, these factors remain largely uncharacterized. We provide evidence that the vitamin A derivative retinoic acid (RA functions as an essential regulator of zebrafish HSC formation. Temporal analyses indicate that RA is required for HSC gene expression prior to dorsal aorta formation, at a time when the predominant RA synthesis enzyme, aldh1a2, is strongly expressed within the paraxial mesoderm and somites. Previous research implicated the Cxcl12 chemokine and Notch signaling pathways in HSC formation. Consequently, to understand how RA regulates HSC gene expression, we surveyed the expression of components of these pathways in RA-depleted zebrafish embryos. During somitogenesis, RA-depleted embryos exhibit altered expression of jam1a and jam2a, which potentiate Notch signaling within nascent endothelial cells. RA-depleted embryos also exhibit a severe reduction in the expression of cxcr4a, the predominant Cxcl12b receptor. Furthermore, pharmacological inhibitors of RA synthesis and Cxcr4 signaling act in concert to reduce HSC formation. Our analyses demonstrate that somite-derived RA functions to regulate components of the Notch and Cxcl12 chemokine signaling pathways during HSC formation.

  14. Clean development mechanism: Perspectives from developing countries

    Energy Technology Data Exchange (ETDEWEB)

    Sari, Agus P.; Meyers, Stephen

    1999-06-01

    This paper addresses the political acceptability and workability of CDM by and in developing countries. At COP-3 in Kyoto in 1997, the general position among developing countries changed from strong rejection of joint implementation to acceptance of CDM. The outgrowth of CDM from a proposal from Brazil to establish a Clean Development Fund gave developing countries a sense of ownership of the idea. More importantly, establishing support for sustainable development as a main goal for CDM overcame the resistance of many developing countries to accept a carbon trading mechanism. The official acceptance of CDM is not a guarantee of continued acceptance, however. Many developing countries expect CDM to facilitate a substantial transfer of technology and other resources to support economic growth. There is concern that Annex I countries may shift official development assistance into CDM in order to gain carbon credits, and that development priorities could suffer as a result. Some fear that private investments could be skewed toward projects that yield carbon credits. Developing country governments are wary regarding the strong role of the private sector envisioned for CDM. Increasing the awareness and capacity of the private sector in developing countries to initiate and implement CDM projects needs to be a high priority. While private sector partnerships will be the main vehicle for resource transfer in CDM, developing country governments want to play a strong role in overseeing and guiding the process so that it best serves their development goals. Most countries feel that establishment of criteria for sustainable development should be left to individual countries. A key issue is how CDM can best support the strengthening of local capacity to sustain and replicate projects that serve both climate change mitigation and sustainable development objectives.There is support among developing countries for commencing CDM as soon as possible. Since official commencement must

  15. Development Application - Terra Nova Development - Development Application Summary

    International Nuclear Information System (INIS)

    1996-01-01

    This summary is part of the application for approval of the development of the Terra Nova Field off the coast of Newfoundland, prepared and submitted by Petro-Canada, on behalf of, and with the cooperation of its co-proponents. The full application consists of five parts, comprising the development plan itself, the Canada-Newfoundland benefits plan detailing commitments with regards to contracts and employment, the environmental impact statement concerning the impact of development on the physical and biological environment, and a statement of socio-economic impacts, characterizing existing and projected impacts of the development on the fisheries, industry, employment, demography, social and public infrastructures and facilities, and socio-cultural issues

  16. Wordpress web application development

    CERN Document Server

    Ratnayake, Rakhitha Nimesh

    2015-01-01

    This book is intended for WordPress developers and designers who want to develop quality web applications within a limited time frame and for maximum profit. Prior knowledge of basic web development and design is assumed.

  17. Practical web development

    CERN Document Server

    Wellens, Paul

    2015-01-01

    This book is perfect for beginners who want to get started and learn the web development basics, but also offers experienced developers a web development roadmap that will help them to extend their capabilities.

  18. International Development Research Centre

    International Development Research Centre (IDRC) Digital Library (Canada)

    ... development. Learn moreArtificial intelligence and human development ... New initiative will match climate knowledge to developing country needs. Aminata Camara ... Shadow Libraries: Access to Knowledge in Global Higher Education.

  19. SUSTAINABLE DEVELOPMENT THROUGH ECO-ECONOMIC DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    Vergina CHIRITESCU

    2013-12-01

    Full Text Available The issue of the relationship between humankind and the environment became scientific and economic concerns of the international community since the first UN Conference on the Human Environment (Stockholm, 1972 and resulted in the work of the World Commission on Environment and Development, established in 1985. Report of the Commission presented in 1987 by GH Brundtland, entitled "Our Common Future" provided the first universally accepted definition of sustainable development as "development that meets the needs of the present generation without compromising the opportunities of future generations to meet their own needs". Brundtland Report, 1987, was reaffirmed by the United Nations Conference on Environment and Development / Earth Summit held in Rio de Janeiro - Brazil, 1992 which established the principles of Agenda 21, which was intended to be a guide implementation of sustainable development for the 21st century, a development that was required to be applied at national, regional and local level. [1] In the context of developing new eco-economic system adopted a number of international conventions that establish detailed obligations of the States and strict implementation deadlines climate change, biodiversity conservation, protection of forests and wetlands, limiting the use of certain chemicals, access information on the state of the environment and other international legal space outlining the practical application of the principles of sustainable economic development in ecological conditions.

  20. Development | Page 24 | IDRC - International Development ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Two years ago, the International Development Research Centre created CIME, a development communication program that reflects the interrelations between Communication at the grassroots level, the exchange of Information, two-way Media, and nonformal Education. This book presents the conceptual framework that led ...

  1. Sustainable development in a developing economy: Challenges ...

    African Journals Online (AJOL)

    Sustainable development implies development which ensures maximization of human well being for today's generation which does not lead to declines in future well being. Attaining this path requires eliminating those negative externalities that are responsible for natural resource depletion and environmental degradation.

  2. Sustainable development goals and inclusive development

    NARCIS (Netherlands)

    Gupta, J.; Vegelin, C.

    Achieving sustainable development has been hampered by trade-offs in favour of economic growth over social well-being and ecological viability, which may also affect the sustainable development goals (SDGs) adopted by the member states of the United Nations. In contrast, the concept of inclusive

  3. Mechanisms underlying the organizer formation in Bufo arenarum embryos.

    Science.gov (United States)

    Manes, M E; Nieto, O L

    1989-06-01

    In the early gastrula of Bufo arenarum the prospective mesoderm was previously identified as a marginal belt of grey cells. To analyze their differentiation capacity explants of these cells were cultured within ectodermal vesicles, in isolation and in combination with vegetal components. When cultured in isolation, dorsal and ventral fragments from the deep marginal zone behaved differently. Whilst ventral explants produced blood cells, dorsal explants failed to differentiate, remaining as masses of yolk-laden cells. On the other hand, both cultures were drastically modified when associated with superficial cells from the blastoporal zone, which caused the following effects: a) Promotion of differentiation in dorsal marginal explants, able now to produce notochordal and somitic structures, in addition to mesenchymatic cells. b) Promotion of dorsalization in ventral marginal explants, which changed their expected destiny developing axial components, similar to those furnished by "activated" dorso marginal explants. On the contrary, combined cultures of animal and vegetal pieces were unable to generate mesodermal structures. These studies suggest that the axial mesoderm, identified as the "organizer", develops from a marginal substrate of genuine mesodermal cells through a dorsalizing inductive stimulus originated in superficial periblastoporal cells.

  4. Dialogue on leadership development

    OpenAIRE

    Reddy, C Manohar; Srinivasan, Vasanthi

    2015-01-01

    Sharing our considerable experience as teachers who have designed and conducted leadership development programmes, we discuss the challenges in the field of leadership development. We distinguish between leader development and leadership development; differentiate leadership theories from leadership development theories; discuss the goals of leadership development programmes and their implications for the design of such programmes – the knowing, being and doing gap and how the goal, cognitive...

  5. Open development networked innovations in international development

    CERN Document Server

    Reilly, Katherine M A

    2014-01-01

    The emergence of open networked models made possible by digital technology has the potential to transform international development. Open network structures allow people to come together to share information, organize, and collaborate. Open development harnesses this power, to create new organizational forms and improve people's lives; it is not only an agenda for research and practice but also a statement about how to approach international development. In this volume, experts explore a variety of applications of openness, addressing challenges as well as opportunities. Open development requires new theoretical tools that focus on real world problems, consider a variety of solutions, and recognize the complexity of local contexts. After exploring the new theoretical terrain, the book describes a range of cases in which open models address such specific development issues as biotechnology research, improving education, and access to scholarly publications. Contributors then examine tensions between open model...

  6. Vehicle Development Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Supports the development of prototype deployment platform vehicles for offboard countermeasure systems.DESCRIPTION: The Vehicle Development Laboratory is...

  7. CDBG Economic Development Activity

    Data.gov (United States)

    Department of Housing and Urban Development — CDBG activity related to economic development, including commercial or industrial rehab, commercial or industrial land acquisition, commercial or industrial...

  8. Dialogue on leadership development

    Directory of Open Access Journals (Sweden)

    C. Manohar Reddy

    2015-03-01

    Full Text Available Sharing our considerable experience as teachers who have designed and conducted leadership development programmes, we discuss the challenges in the field of leadership development. We distinguish between leader development and leadership development; differentiate leadership theories from leadership development theories; discuss the goals of leadership development programmes and their implications for the design of such programmes – the knowing, being and doing gap and how the goal, cognitive understanding vs. deeper internalization vs. transformation would impact the design; the need to synthesize Western and Indian approaches to leadership development; and the importance of designing coherent leadership development programmes which combine multiple methods and approaches.

  9. Sencha Architect app development

    CERN Document Server

    Groner, Loiane

    2013-01-01

    A standard tutorial-based approach for using Sencha Architect to develop applications in Ext JS and Sencha Touch.Sencha Architect App Development is for Ext JS and Sencha Touch developers that are looking to improve their productivity by using Sencha Architect for app development. Basic knowledge of Ext JS and Sencha Touch is required.

  10. Agile Software Development

    Science.gov (United States)

    Biju, Soly Mathew

    2008-01-01

    Many software development firms are now adopting the agile software development method. This method involves the customer at every level of software development, thus reducing the impact of change in the requirement at a later stage. In this article, the principles of the agile method for software development are explored and there is a focus on…

  11. Regional Economic Development

    Science.gov (United States)

    ; Sponsored Work Regional Economic Development Technology Opportunities User Facilities About Us Metrics In the News Publications Policies Feynman Center » Deploying Innovation » Regional Economic Development Regional Economic Development Supporting companies in every stage of development through access to

  12. Information and Rural Development.

    Science.gov (United States)

    Storm, Bonnie L.

    1982-01-01

    Outlines approaches taken to development in lesser developed countries in the past, discusses the importance of appropriate technology and human development, and summarizes the information needs of the rural poor in developing nations. Information dissemination programs using video- and audiotape technology in Bangladesh, Guatemala, and Peru are…

  13. Web Developer | IDRC - International Development Research Centre

    International Development Research Centre (IDRC) Digital Library (Canada)

    Primary Duties or Responsibilities Web Development Leads all technical web ... design, and maintain the corporate website and any other internet properties IDRC ... and testing site for use by members of the website and social media team.

  14. Innovation in Product Development

    DEFF Research Database (Denmark)

    McAloone, Tim C.; Restrepo-Giraldo, John Dairo

    2005-01-01

    The course on Innovation in Product Development attempts to identify and understand the nature of innovation and product development and their important factors. The course takes both a theoretical and a practical approach and employs a mix of lectures, project work and group discussion. Format...... insight. Course content The following aspects of innovation in product development are considered: - Humans and products - Needs and products - Product life - Teams creating products - Products creating business - Product development models - Organising product development - Product development tools...... - The future of product development....

  15. Rural development policy and food industry development

    DEFF Research Database (Denmark)

    Baker, Derek; Abildtrup, Jens; Hedetoft, Anders

    2007-01-01

    Food industry firms in remote areas face a set of constraints, which have motivated the form and function of assistance instruments under various regional and rural development programmes. Recent food industry developments present new challenges to these firms, for which available assistance may...... be less appropriate. This paper employs telephone interviews and workshop discussions with firms in isolated locations to investigate their satisfaction with assistance programmes, their ability to innovate (through product introductions) and respond to challenges in the food industry (the emergence...

  16. Project development symposium

    Energy Technology Data Exchange (ETDEWEB)

    1983-01-01

    Papers were presented on the following: project evaluation; case studies - minerals; finance; applied finance; legal; manpower/industrial relations; and new technologies. Those papers on the coal industry were: mine planning for coal project development; the planning and management of a lignite exploration contract in Thailand; development of the West Cliff extended project; Ulan: a resource development; Saxonvale mine development a case study in project planning and project management; the role of marketing in the development of a new coal project; technical support for coal marketing; infrastructure development for the Ulan project; underground mine project developments; the bucketwheel excavator at Goonyella - a case study; tax aspects of mining development projects; cost of capital mining development projects; and trends in development project finance. 16 papers were abstracted separately.

  17. Expression of the pair-rule gene homologs runt, Pax3/7, even-skipped-1 and even-skipped-2 during larval and juvenile development of the polychaete annelid Capitella teleta does not support a role in segmentation

    Directory of Open Access Journals (Sweden)

    Seaver Elaine C

    2012-04-01

    Full Text Available Abstract Background Annelids and arthropods each possess a segmented body. Whether this similarity represents an evolutionary convergence or inheritance from a common segmented ancestor is the subject of ongoing investigation. Methods To investigate whether annelids and arthropods share molecular components that control segmentation, we isolated orthologs of the Drosophila melanogaster pair-rule genes, runt, paired (Pax3/7 and eve, from the polychaete annelid Capitella teleta and used whole mount in situ hybridization to characterize their expression patterns. Results When segments first appear, expression of the single C. teleta runt ortholog is only detected in the brain. Later, Ct-runt is expressed in the ventral nerve cord, foregut and hindgut. Analysis of Pax genes in the C. teleta genome reveals the presence of a single Pax3/7 ortholog. Ct-Pax3/7 is initially detected in the mid-body prior to segmentation, but is restricted to two longitudinal bands in the ventral ectoderm. Each of the two C. teleta eve orthologs has a unique and complex expression pattern, although there is partial overlap in several tissues. Prior to and during segment formation, Ct-eve1 and Ct-eve2 are both expressed in the bilaterial pair of mesoteloblasts, while Ct-eve1 is expressed in the descendant mesodermal band cells. At later stages, Ct-eve2 is expressed in the central and peripheral nervous system, and in mesoderm along the dorsal midline. In late stage larvae and adults, Ct-eve1 and Ct-eve2 are expressed in the posterior growth zone. Conclusions C. teleta eve, Pax3/7 and runt homologs all have distinct expression patterns and share expression domains with homologs from other bilaterians. None of the pair-rule orthologs examined in C. teleta exhibit segmental or pair-rule stripes of expression in the ectoderm or mesoderm, consistent with an independent origin of segmentation between annelids and arthropods.

  18. Cuban energy development perspectives

    International Nuclear Information System (INIS)

    Berdellans Escobar, Ilse; Perez Martin, David; Lopez Lopez, Ileana; Ricardo Mora, Henry; Gomez De la Torre, Yoandys

    2005-01-01

    In this paper from energy demand scenario calculated for the country until 2025, energy supply options were assessed. Three energy development scenarios considering economic and social development projections and different energy options were evaluated: a reference scenario which includes the nowadays energy development projections; a second scenario basing the development on intensive use of domestic fossil fuels; and a third scenario, where the development is based on the maximum use of domestic renewable energy potential. The results are analyzed and recommendations are formulated

  19. Education for sustainable development

    DEFF Research Database (Denmark)

    Breiting, Søren

    2009-01-01

     An introduction to the idea of sustainable development (SD) and education for sustainable development (ESD) with reference to the international Decade for Education for Sustainable Development . The chapter includes a focus on conflicting interests between present and future generations related ...... to the use of natural resources and other matters, and how that kind of issues can be dealt with in education as ESD....... An introduction to the idea of sustainable development (SD) and education for sustainable development (ESD) with reference to the international Decade for Education for Sustainable Development . The chapter includes a focus on conflicting interests between present and future generations related...

  20. Hanford Site Development Plan

    Energy Technology Data Exchange (ETDEWEB)

    Rinne, C.A.; Curry, R.H.; Hagan, J.W.; Seiler, S.W.; Sommer, D.J. (Westinghouse Hanford Co., Richland, WA (USA)); Yancey, E.F. (Pacific Northwest Lab., Richland, WA (USA))

    1990-01-01

    The Hanford Site Development Plan (Site Development Plan) is intended to guide the short- and long-range development and use of the Hanford Site. All acquisition, development, and permanent facility use at the Hanford Site will conform to the approved plan. The Site Development Plan also serves as the base document for all subsequent studies that involve use of facilities at the Site. This revision is an update of a previous plan. The executive summary presents the highlights of the five major topics covered in the Site Development Plan: general site information, existing conditions, planning analysis, Master Plan, and Five-Year Plan. 56 refs., 67 figs., 31 tabs.

  1. Hanford Site Development Plan

    International Nuclear Information System (INIS)

    Rinne, C.A.; Curry, R.H.; Hagan, J.W.; Seiler, S.W.; Sommer, D.J.; Yancey, E.F.

    1990-01-01

    The Hanford Site Development Plan (Site Development Plan) is intended to guide the short- and long-range development and use of the Hanford Site. All acquisition, development, and permanent facility use at the Hanford Site will conform to the approved plan. The Site Development Plan also serves as the base document for all subsequent studies that involve use of facilities at the Site. This revision is an update of a previous plan. The executive summary presents the highlights of the five major topics covered in the Site Development Plan: general site information, existing conditions, planning analysis, Master Plan, and Five-Year Plan. 56 refs., 67 figs., 31 tabs

  2. Teacher Professional Development

    Directory of Open Access Journals (Sweden)

    Nareerat Rakwichitkul

    2017-06-01

    Full Text Available Teacher professional development are the teachers’ learning process throughout their career stages to ensure that teachers have knowledge, skills and needed competencies for teaching among rapid changes in social, economic and technology which have the impact on learning and teaching. This article deals with the topics of the framework for teaching, teacher career stages and teacher professional development. The research findings related to teacher professional development, teacher professional development activities, suggestions for planning the professional development. Those research findings can be applied and implemented by the school principals, educational supervisors and other professional developers.

  3. Hanford Site Development Plan

    International Nuclear Information System (INIS)

    Hathaway, H.B.; Daly, K.S.; Rinne, C.A.; Seiler, S.W.

    1993-05-01

    The Hanford Site Development Plan (HSDP) provides an overview of land use, infrastructure, and facility requirements to support US Department of Energy (DOE) programs at the Hanford Site. The HSDP's primary purpose is to inform senior managers and interested parties of development activities and issues that require a commitment of resources to support the Hanford Site. The HSDP provides an existing and future land use plan for the Hanford Site. The HSDP is updated annually in accordance with DOE Order 4320.1B, Site Development Planning, to reflect the mission and overall site development process. Further details about Hanford Site development are defined in individual area development plans

  4. Economic Development and Development of Human Resources

    Directory of Open Access Journals (Sweden)

    Metod Černetič

    1998-12-01

    Full Text Available Černetič deals with certain dilemmas and problems related to employee training within companies, and discusses the complexity of the relationship between technological development and education, developmental gap between the developed and underdevdoped economies, and the goals of social development in Slovenia. Cernetič stresses that training programmes should above all provide flexibility of employment; the competitive edge of an entire state actually depends on effective use of human resources. Slovenia cannot exert any substantial influence on the global economy, it can only follow the main market trends. Knowledge is therefore of great importance, as the wealth of smaller nations is primarily based on the education level of their inhabitants.

  5. DEVELOPING STATE POLICIES SUPPORTIVE OF BIOENERGY DEVELOPMENT

    Energy Technology Data Exchange (ETDEWEB)

    Kathryn Baskin

    2005-04-30

    Working within the context of the Southern States Biobased Alliance (SSBA) and with officials in each state, the Southern States Energy Board (SSEB) is identifying bioenergy-related policies and programs within each state to determine their impact on the development, deployment or use of bioenergy. In addition, SSEB will determine which policies have impacted industry's efforts to develop, deploy or use biobased technologies or products. As a result, SSEB will work with the Southern States Biobased Alliance to determine how policy changes might address any negative impacts or enhance positive impacts. In addition to analysis of domestic policies and programs, this project will include the development of a U.S.-Brazil Biodiesel Pilot Project. The purpose of this effort is to promote and facilitate the commercialization of biodiesel and bioenergy production and demand in Brazil.

  6. DEVELOPING STATE POLICIES SUPPORTIVE OF BIOENERGY DEVELOPMENT

    Energy Technology Data Exchange (ETDEWEB)

    Kathryn Baskin

    2004-10-31

    Working within the context of the Southern States Biobased Alliance (SSBA) and with officials in each state, the Southern States Energy Board (SSEB) is identifying bioenergy-related policies and programs within each state to determine their impact on the development, deployment or use of bioenergy. In addition, SSEB will determine which policies have impacted industry's efforts to develop, deploy or use biobased technologies or products. As a result, SSEB will work with the Southern States Biobased Alliance to determine how policy changes might address any negative impacts or enhance positive impacts. In addition to analysis of domestic policies and programs, this project will include the development of a U.S.-Brazil Biodiesel Pilot Project. The purpose of this effort is to promote and facilitate the commercialization of biodiesel and bioenergy production and demand in Brazil.

  7. DEVELOPING STATE POLICIES SUPPORTIVE OF BIOENERGY DEVELOPMENT

    International Nuclear Information System (INIS)

    Kathryn Baskin

    2001-01-01

    Working within the context of the Southern States Biobased Alliance (SSBA) and with officials in each state, the Southern States Energy Board (SSEB) is identifying bioenergy-related policies and programs within each state to determine their impact on the development, deployment or use of bioenergy. In addition, SSEB will determine which policies have impacted industry's efforts to develop, deploy or use biobased technologies or products. As a result, SSEB will work with the Southern States Biobased Alliance to determine how policy changes might address any negative impacts or enhance positive impacts

  8. DEVELOPING STATE POLICIES SUPPORTIVE OF BIOENERGY DEVELOPMENT

    International Nuclear Information System (INIS)

    Kathryn Baskin

    2002-01-01

    Working within the context of the Southern States Biobased Alliance (SSBA) and with officials in each state, the Southern States Energy Board (SSEB) is identifying bioenergy-related policies and programs within each state to determine their impact on the development, deployment or use of bioenergy. In addition, SSEB will determine which policies have impacted industry's efforts to develop, deploy or use biobased technologies or products. As a result, SSEB will work with the Southern States Biobased Alliance to determine how policy changes might address any negative impacts or enhance positive impacts

  9. FPG Child Development Institute

    Science.gov (United States)

    ... shows how implicit racial biases are adversely affecting African American students--especially boys... read more Emphasis Areas ... Development, Teaching, and Learning The Frank Porter Graham Child Development Institute will partner with Zero to Three ...

  10. Odoo development essentials

    CERN Document Server

    Reis, Daniel

    2015-01-01

    This book is intended for developers who need to quickly become productive with Odoo. You are expected to have experience developing business applications, as well as an understanding of MVC application design and knowledge of the Python programming language.

  11. Game development tool essentials

    CERN Document Server

    Berinstein, Paula; Ardolino, Alessandro; Franco, Simon; Herubel, Adrien; McCutchan, John; Nedelcu, Nicusor; Nitschke, Benjamin; Olmstead, Don; Robinet, Fabrice; Ronchi, Christian; Turkowski, Rita; Walter, Robert; Samour, Gustavo

    2014-01-01

    Offers game developers new techniques for streamlining the critical game tools pipeline. Inspires game developers to share their secrets and improve the productivity of the entire industry. Helps game industry practitioners compete in a hyper-competitive environment.

  12. Next Generation Software Development

    National Research Council Canada - National Science Library

    Manna, Zohar

    2005-01-01

    Under this grant we have studied the development of a scientifically sound basis for software development that builds on widely used pragmatic methods but is firmly grounded in well-established formal...

  13. REGIONAL DEVELOPMENT IN ROMANIA

    Directory of Open Access Journals (Sweden)

    Remus Gherman

    2015-10-01

    Full Text Available Regional development policy is a policy of investment for economic development by supporting competitiveness, increasing the standards of living, improving the quality of life, creating new jobs. Regions and regional development policy occupies in recent decades an increasingly important position in the list of the economic and social factors being found on the agendas of governments, both central and local authorities, of political groups and civil society. Regional development and regional development policy in Romania are present both in the economic reform and in social one. Development Regions from Romania are set up in 1998 by Law number 151 and supported by their own institutional framework. The applicability of regional development in Romania must take into account the fundamental elements of the possibilities of Regional Development, meaning the major indicators of reference for measuring the level of disparities, GDP per capita and unemployment.

  14. Your Child's Development: Newborn

    Science.gov (United States)

    ... Your Child's Development: Newborn Print en español El desarrollo de su hijo: recién nacido From the moment ... when touched on the sole of the foot Social and Emotional Development soothed by a parent's voice ...

  15. Mobile systems development

    DEFF Research Database (Denmark)

    Pedersen, Ole; Kristiansen, Martin Lund; Kammersgaard, Marc N.

    2007-01-01

    in XP. In general, we find XP well-suited for mobile systems development projects. However, based on our experiences and an analytical comparison we propose the following modifications to XP: Make an essential design to avoid the worst time waste during refactoring. For faster development, reuse code......Development of mobile software is Surrounded by much uncertainty. Immature software platforms on mobile clients, a highly competitive market calling for innovation, efficiency and effectiveness in the development life cycle, and lacking end-user adoption are just some of the realities facing...... development teams in the mobile software industry. By taking a process view on development of mobile systems we seek to explore the strengths and limitations of eXtreme Programming (XP) in the context of mobile software development. Following an experimental approach a mobile systems development project...

  16. Localisation for industrial development

    CSIR Research Space (South Africa)

    Bhugwandin, Ashley

    2017-10-01

    Full Text Available This presentation focuses on localisation for industrial development, and is presented by Ashley Bhugwandin at The 6th CSIR Conference: Ideas that work for industrial development, 5-6 October 2017, CSIR International Convention Centre, Pretoria...

  17. Normal growth and development

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/002456.htm Normal growth and development To use the sharing features on this page, please enable JavaScript. A child's growth and development can be divided into four periods: ...

  18. Gammasphere software development

    International Nuclear Information System (INIS)

    Piercey, R.B.

    1993-01-01

    Activities of the nuclear physics group are described. Progress was made in organizing the Gammasphere Software Working Group, establishing a nuclear computing facility, participating in software development at Lawrence Berkeley, developing a common data file format, and adapting the ORNL UPAK software to run at Gammasphere. A universal histogram object was developed that defines a file format and provides for an objective-oriented programming model. An automated liquid nitrogen fill system was developed for Gammasphere (110 Ge detectors comprise the sphere)

  19. Coalbed gas development

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This book includes: Overview of coalbed gas development; Coalbed gas development in the West Coalbed gas development on Indian lands; Multi-mineral development conflicts; Statutory solutions to ownership disputes; State and local regulation; Environmental regulations; Status of the section 29 tax credit extension; Using the section 29 credit; Leasing coalbed gas prospects; Coalbed gas joint operating agreements and Purchase and sale agreements for coalbed gas properties

  20. Development | Page 28 | IDRC - International Development ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    The Dnipro River is Europe's second longest river and flows through the heartland of Russia, Belarus, and Ukraine. For many centuries, it has played a vital role in the historical, cultural, religious and economic development of this vast region. Indeed, it is true to say that nobody can understand this vast region of the world ...

  1. Development | Page 15 | IDRC - International Development ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Land is an important source of security against poverty across the developing world, but, in many places, unequal rights to land put women at a disadvantage, ... Upgrading is a key concept for value chain analysis and refers to the acquisition of technological capabilities and market linkages that enable firms to improve their ...

  2. Development | Page 32 | IDRC - International Development ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    This book describes and analyzes the 3-year-long “L-20” project, whose objective ... in the environment for research and development (R&D) around the world. ... the “capability approach” of economist and Nobel Prize laureate Amartya Sen.

  3. Dental Curriculum Development in Developing Countries.

    Science.gov (United States)

    Phantumvanit, Prathip

    1996-01-01

    Since establishment of formal dental education in Southeast Asia, changes stemming from research and technology have led to dental curriculum changes. Development of the dental curriculum can be divided into three phases: disease oriented; health oriented; and community oriented. Evolution of these phases is traced in the dental curricula of Laos,…

  4. The China Development Bank and Sustainable Development

    Directory of Open Access Journals (Sweden)

    Valentina Levanchuk

    2016-11-01

    Full Text Available In this article, the author presents an empirical study of sustainable banking in China and examines the flagship China DevelopmentBank (CDB. The CDB is directly supervised by the State Council of the People’s Republic of China and is one ofthe largest state-owned financial institutions in the country. Its overseas lending is growing rapidly; it increasingly acts as aglobal player, influenced by a variety of international actors. Using the mercantilist framework, the author investigates how the CDB’s social policies diverge from those set by the Chinese authorities. The analysis discusses CDB’s policy variations that are not in line with government interests or prescribed directly by governmental bodies. It concludes that the bank has been active in developing and establishing its own corporate strategy for implementing the concept of sustainable development to promote a balanced development of the economy, society and the environment. That strategy contains the norms and rules set by Chinese regulatory agencies with regard to social and environmental areas, as well as important elements ofthe international practice of corporate responsibility and sustainable funding. The CDB is most likely driven by its desire tobe considered internationally a good corporate citizen and often acts independently from governmental guidance, which insome sense undermines mercantilist perceptions.

  5. Fusion development and technology

    International Nuclear Information System (INIS)

    Montgomery, D.B.

    1991-01-01

    This report discusses the following topics: superconducting magnet technology high field superconductors; advanced magnetic system and divertor development; poloidal field coils; gyrotron development; commercial reactor studies -- Aries; ITER physics; ITER superconducting PF scenario and magnet analysis; and safety, environmental and economic factors in fusion development

  6. Marketing Human Resource Development.

    Science.gov (United States)

    Frank, Eric, Ed.

    1994-01-01

    Describes three human resource development activities: training, education, and development. Explains marketing from the practitioners's viewpoint in terms of customer orientation; external and internal marketing; and market analysis, research, strategy, and mix. Shows how to design, develop, and implement strategic marketing plans and identify…

  7. Moral Development in Adolescence

    Science.gov (United States)

    Hart, Daniel; Carlo, Gustavo

    2005-01-01

    Themes in the papers in this special issue of the "JRA" on moral development are identified. We discuss the intersection of moral development research with policy concerns, the distinctive qualities of moral life in adolescence that warrant investigation, the multiple connotations of "moral", the methods typical of moral development research, and…

  8. World Development Report 1984.

    Science.gov (United States)

    World Bank, Washington, DC.

    This report, seventh in a series of annual publications, examines the relationship between population change and development, showing why continuing rapid population growth in developing countries is likely to mean a lower quality of life for millions of people. The first part of the report concludes that the economies of developing countries can…

  9. The sustainable development

    International Nuclear Information System (INIS)

    2004-01-01

    In the framework of the sustainable development week (june 2003), Actu Environnement published a complete document on the sustainable development to inform the public, recall the main steps of this notion (Rio conference and the following conferences) and the possible employments. It presents also the main organizations acting in the sustainable development domain. (A.L.B.)

  10. Participatory Development Communication

    International Development Research Centre (IDRC) Digital Library (Canada)

    Training Needs in Participatory Development Communication .... to the development of society (communications in the service of development), ... There are also some definitions that give a more restrictive meaning to the way ...... Although proponents of participation appreciate that there is more good than bad in the ...

  11. Mechanisms in Plant Development

    Energy Technology Data Exchange (ETDEWEB)

    Hake, Sarah [USDA ARS Plant Gene Expression Center

    2013-08-21

    This meeting has been held every other year for the past twenty-two years and is the only regularly held meeting focused specifically on plant development. Topics covered included: patterning in developing tissues; short and long distance signaling; differentiation of cell types; the role of epigenetics in development; evolution; growth.

  12. Curriculum Development in Geomorphology.

    Science.gov (United States)

    Gregory, Kenneth J.

    1988-01-01

    Examines the context of present curriculum development in geomorphology and the way in which it has developed in recent years. Discusses the content of the geomorphology curriculum in higher education and the consequences of curriculum development together with a consideration of future trends and their implications. (GEA)

  13. Interpreting sustainable development

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    Over the past decade, the term" sustainable development"has emerged as the principal concept in the development field. The concept emerged in the 1970s and was first promoted in the international environmental and development communities with the publication of the " world conservation strategy"(1980). It was popularized by the Brundtland report, " Our common future"(1987). The Brundtland Commission defined sustainable development as " development which meets the needs of the present, without compromising the sustainability of future generation to meet their own needs". The Earth Summit(1992) established "sustainable development" as the most important policy of the 21st century. Since then, the relationship between development and environment has been widely discussed and sustainabale development is now an important part of the vocabulary of environmental policy research and analysis. In this paper, we begin by tracing the evolution of the concept of sustainable development. Definitions of sustainable development in ecology, economics and sociology are then explored and discussed. This paper also examine the contribution that a broadly-based concept of sustainable development can make: as a goal, an attitude and as a guiding principle for integrating economic development and environmental protection.

  14. Professional Development. Issue Brief

    Science.gov (United States)

    Keleher, Julia

    2017-01-01

    In this professional development research brief, the author sets forth the overarching considerations that should be kept in mind when conceptualizing professional development for educators working with neglected or delinquent youth (N or D). The brief begins by defining professional development and demonstrating why it is a critical support for…

  15. Institutionalizing Staff Development.

    Science.gov (United States)

    Shawl, William F.

    Three years ago, Golden West College (GWC) decided to make a major commitment to staff development as a means of revitalizing the college. This commitment was evidenced through the creation of the position of Dean of Educational Development, who is responsible solely for serving faculty needs; the Educational Development Center, which houses the…

  16. Domestic biogas development in developing countries

    International Nuclear Information System (INIS)

    Rakotojaona, Loic

    2013-07-01

    Communities that rely mostly on agriculture and livestock farming in developing countries can face strong pressure related to: - Energy access: for instance, in Africa, it is estimated that 68% of the population live without clean cooking facilities [1]. Energy access plays a key role in poverty alleviation. - Resources depletion: if a household uses firewood for cooking purposes, forests depletion in some areas makes firewood collection tougher. - Climate change mitigation: agriculture (i.e. the production of crop and livestock products) accounts for 13.5%2 of the global GHG emissions, and extensive systems are sometimes blamed for being less efficient than intensive ones when it comes to climate change mitigation (given that the later involve lower direct emissions per kg of product). In this context, access to clean and sustainable energy through domestic biogas production can help rural communities alleviate current pressures on the environment. In an urban context, domestic biogas in developing countries is also considered as a means for improving hygiene conditions (especially when it comes to public washrooms issues). This report only focuses on domestic biogas development within the frame of small scale agriculture and livestock production (i.e. in rural areas). The main objective of this document is to provide domestic biogas project developers with relevant information on the key issues to have in mind regarding national integration of such projects. This document gives a general presentation of domestic biogas and its main environmental, social and economic benefits. It also browses the main aspects one should have in mind (checklist) in order to assess local risks and opportunities for domestic biogas development

  17. Competence development in UAS

    DEFF Research Database (Denmark)

    Thorslund, Jørgen; Brodersen, Anne Mygind

    As a University of Applied Science (UAS) University College Lillebaelt in Denmark is addressing education, knowledge production and professional development in perspective of life-long and life-wide learning. It is our basic assumption that that internal competence development ? individually...... and organizationally - among UAS educators should be based on same learning concepts as used in professional development to avoid parallelism. Do for yourself, what you preach for others. Second, competence development of faculty is a central element in transformation of our institutions from schools of higher...... education to universities of applied science (UAS). Competence development strategies should thus include objectives for the institutions ability to contribute to knowledge production....

  18. Environmental Control Subsystem Development

    Science.gov (United States)

    Laidlaw, Jacob; Zelik, Jonathan

    2017-01-01

    Kennedy Space Center's Launch Pad 39B, part of Launch Complex 39, is currently undergoing construction to prepare it for NASA's Space Launch System missions. The Environmental Control Subsystem, which provides the vehicle with an air or nitrogen gas environment, required development of its local and remote display screens. The remote displays, developed by NASA contractors and previous interns, were developed without complete functionality; the remote displays were revised, adding functionality to over 90 displays. For the local displays, multiple test procedures were developed to assess the functionality of the screens, as well as verify requirements. One local display screen was also developed.

  19. COMPETITIVENESS IN REGIONAL DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    ELENA MĂDĂLINA OPRIȚESCU

    2012-12-01

    Full Text Available The development and diversification of the economic activities, the stimulation of investments both in the public sector, but mainly in the private one, the reduction of unemployment, the improvement of living standards are just some of the concepts aimed at by the regional development. The main method which can lead to a balanced development of the regions is financing them differentially so that the underdeveloped regions would obtain proportionally more funds that the developed ones. At a region level, the main objective is represented by the more accelerated growth of the less developed regions, in an effort to diminish the inter-regional and intra-regional development disparities. A key role is played by the sustainable economic growth concept, while also analyzing the competitiveness at a regional level, as well as the main development factors.

  20. World Development Report 2008: Agriculture for development

    OpenAIRE

    The World Bank

    2007-01-01

    The world's demand for food is expected to double within the next 50 years, while the natural resources that sustain agriculture will become increasingly scarce, degraded, and vulnerable to the effects of climate change. In many poor countries, agriculture accounts for at least 40 percent of GDP and 80 percent of employment. At the same time, about 70 percent of the world's poor live in rural areas and most depend on agriculture for their livelihoods. World Development Report 2008 seeks t...

  1. Smad4-dependent pathways control basement membrane deposition and endodermal cell migration at early stages of mouse development

    Directory of Open Access Journals (Sweden)

    Taylor Jennifer M

    2009-10-01

    Full Text Available Abstract Background Smad4 mutant embryos arrest shortly after implantation and display a characteristic shortened proximodistal axis, a significantly reduced epiblast, as well as a thickened visceral endoderm layer. Conditional rescue experiments demonstrate that bypassing the primary requirement for Smad4 in the extra-embryonic endoderm allows the epiblast to gastrulate. Smad4-independent TGF-β signals are thus sufficient to promote mesoderm formation and patterning. To further analyse essential Smad4 activities contributed by the extra-embryonic tissues, and characterise Smad4 dependent pathways in the early embryo, here we performed transcriptional profiling of Smad4 null embryonic stem (ES cells and day 4 embryoid bodies (EBs. Results Transcripts from wild-type versus Smad4 null ES cells and day 4 EBs were analysed using Illumina arrays. In addition to several known TGF-β/BMP target genes, we identified numerous Smad4-dependent transcripts that are mis-expressed in the mutants. As expected, mesodermal cell markers were dramatically down-regulated. We also observed an increase in non-canonical potency markers (Pramel7, Tbx3, Zscan4, germ cell markers (Aire, Tuba3a, Dnmt3l as well as early endoderm markers (Dpp4, H19, Dcn. Additionally, expression of the extracellular matrix (ECM remodelling enzymes Mmp14 and Mmp9 was decreased in Smad4 mutant ES and EB populations. These changes, in combination with increased levels of laminin alpha1, cause excessive basement membrane deposition. Similarly, in the context of the Smad4 null E6.5 embryos we observed an expanded basement membrane (BM associated with the thickened endoderm layer. Conclusion Smad4 functional loss results in a dramatic shift in gene expression patterns and in the endodermal cell lineage causes an excess deposition of, or an inability to breakdown and remodel, the underlying BM layer. These structural abnormalities probably disrupt reciprocal signalling between the epiblast and

  2. ACCELERATING CONSTRUCTION INDUSTRY DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    Mohan M. Kumaraswamy

    2006-06-01

    Full Text Available The needs for construction industry development are initially viewed from the broader perspectives of imperatives for infrastructure development and national development. All these are clearly more critical in developing countries. A non-exhaustive set of potential drivers and common barriers to construction industry development is identified from previous research. These suggest the usefulness of consolidating a cluster of recent proposals and exercises aiming at (a construction organization development in terms of an over-arching management support system model, as well as improved information and knowledge management; and (b project team development in the context of relationally integrated teams and supply chains, joint risk management and ‘technology and knowledge exchange’ in joint ventures, as well as longer term public private partnerships. These apparently disparate research thrusts are threaded together into a pattern that may inspire, if not feed, specific research and development (R & D agendas for construction industry development in different countries according to their own priorities, constraints and stages of infrastructure and national development.

  3. Cooperative method development

    DEFF Research Database (Denmark)

    Dittrich, Yvonne; Rönkkö, Kari; Eriksson, Jeanette

    2008-01-01

    The development of methods tools and process improvements is best to be based on the understanding of the development practice to be supported. Qualitative research has been proposed as a method for understanding the social and cooperative aspects of software development. However, qualitative...... research is not easily combined with the improvement orientation of an engineering discipline. During the last 6 years, we have applied an approach we call `cooperative method development', which combines qualitative social science fieldwork, with problem-oriented method, technique and process improvement....... The action research based approach focusing on shop floor software development practices allows an understanding of how contextual contingencies influence the deployment and applicability of methods, processes and techniques. This article summarizes the experiences and discusses the further development...

  4. Hanford Site Development Plan

    International Nuclear Information System (INIS)

    Hathaway, H.B.; Daly, K.S.; Rinne, C.A.; Seiler, S.W.

    1992-05-01

    The Hanford Site Development Plan (HSDP) provides an overview of land use, infrastructure, and facility requirements to support US Department of Energy (DOE) programs at the Hanford Site. The HSDP's primary purpose is to inform senior managers and interested parties of development activities and issues that require a commitment of resources to support the Hanford Site. The HSDP provides a land use plan for the Hanford Site and presents a picture of what is currently known and anticipated in accordance with DOE Order 4320.1B. Site Development Planning. The HSDP wig be updated annually as future decisions further shape the mission and overall site development process. Further details about Hanford Site development are defined in individual area development plans

  5. Energy and Sustainable Development

    International Nuclear Information System (INIS)

    2013-01-01

    None of the eight Millennium Development Goals (MDGs) adopted by the United Nations in 2000 directly addressed energy, although for nearly all of them - from eradicating poverty and hunger to improving education and health - progress has depended on greater access to modern energy. Thirteen years later, energy is being given more attention. The target date for the MDGs is 2015, and in 2012 the UN began deliberations to develop sustainable development goals to guide support for sustainable development beyond 2015. The Future We Want, the outcome document of the 2012 United Nations Conference on Sustainable Development (also known as Rio+20) gives energy a central role: ''We recognize the critical role that energy plays in the development process, as access to sustainable modern energy services contributes to poverty eradication, saves lives, improves health and helps provide for basic human needs''

  6. Energy and development

    Energy Technology Data Exchange (ETDEWEB)

    Gururaja, J.

    1980-03-15

    The developing countries will require higher per capita energy for improving the quality of life. This paper examines the goals and strategies for development vis-a-vis those of the developed countries. Crucial issues in India are listed. The role of technology in the utilization of energy is discussed. Difficulties in choosing the technology are pointed out. The problem of integrating several alternative energy sources in villages is mentioned. Environmental issues are considered. (DLC)

  7. Centrifuge design and development

    International Nuclear Information System (INIS)

    Edwards, T.T.; Holmes, M.D.

    1987-01-01

    BNFL has been enriching uranium on an industrial scale using the centrifuge process for over a decade. Together with its Urenco partners, a joint development programme has been and is being vigorously pursued to reduce specific costs, increase output and maintain competitiveness throughout the 1990s. The paper summarises the development of the centrifuge from its earliest concepts through to the centrifuges of today which are jointly designed by the Urenco partners. The potential for further development is also examined. (author)

  8. Fusion development and technology

    International Nuclear Information System (INIS)

    Montgomery, D.B.

    1992-01-01

    This report discusses the following: superconducting magnet technology; high field superconductors; advanced magnetic system and divertor development; poloidal field coils; gyrotron development; commercial reactor studies--aries; ITER physics: alpha physics and alcator R ampersand D for ITER; lower hybrid current drive and heating in the ITER device; ITER superconducting PF scenario and magnet analysis; ITER systems studies; and safety, environmental and economic factors in fusion development

  9. CANDU project development

    Energy Technology Data Exchange (ETDEWEB)

    Hedges, K R [Atomic Energy of Canada Ltd., Mississauga, ON (Canada)

    1996-12-31

    Advanced CANDU reactor design strategy follows an evolutionary approach, taking manageable steps in the development of power plants from today`s available designs, and in parallel carrying out longer-term studies to develop future-generation reactor concepts. The major emphasis is on safety, on on reducing cost and schedule. New features are developed and thoroughly proof-tested before introduction into designs, in order to maximize owner confidence. (author). 4 figs.

  10. Renewable energy project development

    Energy Technology Data Exchange (ETDEWEB)

    Ohi, J.

    1996-12-31

    The author presents this paper with three main thrusts. The first is to discuss the implementation of renewable energy options in China, the second is to identify the key project development steps necessary to implement such programs, and finally is to develop recommendations in the form of key issues which must be addressed in developing such a program, and key technical assistance needs which must be addressed to make such a program practical.

  11. Finance and Economic Development

    OpenAIRE

    Panizza, Ugo

    2012-01-01

    Published by Palgrave Macmillan This chapter reviews the literature on finance and economic development. It starts with a description of the roles of finance, a definition of financial efficiency, and a discussion of whether countries may have financial sectors that are ‘too large’ compared to the size of the domestic economy. Next, the author describes several indicators of financial development and reviews the literature on the relationship between financial development and economic growth....

  12. CANDU project development

    International Nuclear Information System (INIS)

    Hedges, K.R.

    1995-01-01

    Advanced CANDU reactor design strategy follows an evolutionary approach, taking manageable steps in the development of power plants from today's available designs, and in parallel carrying out longer-term studies to develop future-generation reactor concepts. The major emphasis is on safety, on on reducing cost and schedule. New features are developed and thoroughly proof-tested before introduction into designs, in order to maximize owner confidence. (author). 4 figs

  13. Tax havens and development

    OpenAIRE

    Norwegian Government Commission on Capital Flight from Poor Countries

    2009-01-01

    Tax havens harm both industrialised and developing countries, but the damaging impacts are largest in developing countries. This is partly because these countries are poor and thereby have more need to protect their national tax base, and partly because they generally have weaker institutions and thereby fewer opportunities for enforcing the laws and regulations they adopt. Tax treaties between tax havens and developing countries often contribute to a significant reduction in the tax base of...

  14. Patterns of strategy development

    OpenAIRE

    Bailey, Andy; Johnson, Gerry

    1996-01-01

    This paper builds on a multidimensional framework of strategy development to more clearly understand the processes by which strategy develops within organisations. It reports on a survey based research project which employs senior executives’ perceptions of the strategy development process in their organisations to examine how context specific configurations of dimensions explaining such processes can advance our understanding of strategic management. Six configurations are ide...

  15. Strategy Development in Organisations

    DEFF Research Database (Denmark)

    Sørensen, Lene

    1999-01-01

    There exist certain ambiguities with the converging fields of information technology and organisational strategy development. The term "IT strategy" has evolved and reflects in some respects this confusion. This paper discusses some of the ambiguities and difficulties of the term "IT strategy......" as used in practice and literature. Emphasis is put on how the term is related to the problem, the organisation, the strategy process and the practical way of methodologically developing the strategy. Finally, alternative strategy developing perspectives are presented....

  16. Environment and development

    International Nuclear Information System (INIS)

    1992-01-01

    As part of its contribution to the United Nations Conference on Environment and Development, held in Rio de Janeiro in June 1992, the IAEA produced a booklet entitled ''Nuclear Power, Nuclear Techniques and Sustainable Development''. The second half of this dealt with the relevance of the IAEA's work to ''Agenda 21'', an agenda of environmental conservation and sustainable development for the twenty-first century. This article briefly summarizes the text

  17. Node web development

    CERN Document Server

    Herron, David

    2013-01-01

    Presented in a simple, step-by-step format, this book is an introduction to web development with Node.This book is for anybody looking for an alternative to the ""P"" languages (Perl, PHP, Python), or anyone looking for a new paradigm of server-side application development.The reader should have at least a rudimentary understanding of JavaScript and web application development.

  18. Agile software development

    CERN Document Server

    Dingsoyr, Torgeir; Moe, Nils Brede

    2010-01-01

    Agile software development has become an umbrella term for a number of changes in how software developers plan and coordinate their work, how they communicate with customers and external stakeholders, and how software development is organized in small, medium, and large companies, from the telecom and healthcare sectors to games and interactive media. Still, after a decade of research, agile software development is the source of continued debate due to its multifaceted nature and insufficient synthesis of research results. Dingsoyr, Dyba, and Moe now present a comprehensive snapshot of the kno

  19. Pro Access 2010 Development

    CERN Document Server

    Collins, Mark

    2011-01-01

    Pro Access 2010 Development is a fundamental resource for developing business applications that take advantage of the features of Access 2010 and the many sources of data available to your business. In this book, you'll learn how to build database applications, create Web-based databases, develop macros and Visual Basic for Applications (VBA) tools for Access applications, integrate Access with SharePoint and other business systems, and much more. Using a practical, hands-on approach, this book will take you through all the facets of developing Access-based solutions, such as data modeling, co

  20. Nuclear standardization development study

    International Nuclear Information System (INIS)

    Pan Jianjun

    2010-01-01

    Nuclear industry is the important part of national security and national economic development is key area of national new energy supported by government. nuclear standardization is the important force for nuclear industry development, is the fundamental guarantee of nuclear safe production, is the valuable means of China's nuclear industry technology to the world market. Now nuclear standardization faces to the new development opportunity, nuclear standardization should implement strategy in standard system building, foreign standard research, company standard building, and talented people building to meet the requirement of nuclear industry development. (author)

  1. Hydroelectricity and sustainable development

    International Nuclear Information System (INIS)

    Dubeau, D.

    1995-01-01

    From 1975 to 1992, hydroelectricity helped reduce greenhouse gas emissions in Quebec by 20%. For Hydro-Quebec, energy conservation and hydroelectric development are basic complementary tools for sustainable development. Recent studies show that developing only 50% of economically exploitable hydroelectric potential (30% of the gross theoretical potential) of different regions worldwide would considerably reduce greenhouse gas and SO 2 emissions. However, hydroelectric systems produce environmental and social impacts locally that require mitigative measures. To fulfill its mandate in a sustainable development context, Hydro-Quebec has adopted methods such as integrated resource planning, the assessment of externalities, multi criteria decision tools and public participations

  2. Shopify application development

    CERN Document Server

    Larkin, Michael

    2014-01-01

    This is an easy-to follow manual that will guide you through the entire process of application development with Shopify, beginning with the installation and configuration of your local development environment for your app to the deployment of the app to Heroku. If you are a web developer or a designer who wants to extend Shopify stores by building apps, then this book is for you. A basic understanding of programming concepts and some familiarity with Shopify is all that is required to get started with Shopify app development.

  3. Small Business Development Center

    Data.gov (United States)

    Small Business Administration — Small Business Development Centers (SBDCs) provide assistance to small businesses and aspiring entrepreneurs throughout the United States and its territories. SBDCs...

  4. Creativity and Strategy Development

    DEFF Research Database (Denmark)

    Sørensen, Lene Tolstrup; Vidal, Rene Victor Valqui

    This paper focus on how creative thinking, processes and methods can support the strategy development and planning process in organisations. First, several fundamental concepts related to both strategy development and planning are stipulated. In addition, the concept of living organisation...... will be discussed as well as the interaction between strategy and creativity. Then, methodological ideas to support the strategy making process are presented enhancing the use of creative methods and tools. Finally, a case study related to the development of a strategy for organisational development using...... creativity tools is discussed....

  5. Visualforce development cookbook

    CERN Document Server

    Bowden, Keir

    2013-01-01

    Visualforce Development Cookbook is written in such a way that even complex concepts are explained in an easy-to-understand manner. Following a Cookbook structure, the book covers some essential technical scenarios and includes over 75 recipes focusing on real-world development problems. This book is packed with illustrations and also contains lots of code samples for the better understanding of the reader.""Visualforce Development Cookbook"" is aimed at developers who have already grasped the basics of Visualforce. Awareness of the standard component library and the purpose of controllers is

  6. Physics and sustainable development

    International Nuclear Information System (INIS)

    Emre, B.

    2005-01-01

    Is there a relationship with between physics and sustainable development? The answer of this question is yes since in the past to the health and welfare of people and nations physics has made tremendous contributions. Think of the contributions that physics has made to the world economy in areas such as electronics, materials, and computer technology, also to health x-rays, magnetic resonance imaging and nuclear medicine. However, many of these contributions have benefited people in the developed world more than those in the developing world. Moreover current physics curricula do not have vision of to offer the student a full perspective of sustainable development

  7. REGIONAL DEVELOPMENT STRATEGY

    Directory of Open Access Journals (Sweden)

    Vaduva Maria

    2011-01-01

    Full Text Available Regional development policies in the EU Member States have included tools whoseimportance varied from one country to another. Can be identified by negative incentives forregional development policy towards location in crowded areas or control over the location,the reallocation of economic activities in national territory, creation of adequateinfrastructure, measures to enhance development, financial incentives granted toenterprises. Sustainable business development, rehabilitation of social infrastructure,including social housing and improved social services. Improved regional and localtransportation are key areas of intervention rehabilitation and upgrading of county roads,city streets, including road construction and rehabilitation of belt.

  8. Environment, employment and development

    International Nuclear Information System (INIS)

    Bhalla, A.S.

    1992-01-01

    It is generally recognised that the question of sustainable development is a global problem, emphasizing the increasingly interdependent nature of relationships among nations. Solutions to the problem are as much political as they are economic and technological. Notwithstanding the deepening and widening of the debate on sustainable development, its implications for employment - a major concern of the ILO under its World Employment Programme - have remained largely unexplored. This volume, therefore, has a very modest objective, namely to place the employment question on the policy agenda in the context of the current debate on environment and development. The design of environmental policies should allow for the differences that exist between countries with a high level of development and technological dynamism and those with a low level of development and low technological capability. One must also recognize the costs imposed by adjustment and the consequent distributional impact. In the long term, technology choice plays a crucial role in promoting sustainable development in both industrialized and developing countries. It is not only environment-friendly technologies that need to be developed and diffused; in the case of the least developed countries, technological transformation needs to be accelerated in order to minimise their dependence on natural resources for economic growth. Refs, figs and tabs

  9. Energy, technology, development

    Energy Technology Data Exchange (ETDEWEB)

    Goldemberg, J [Ministerio da Educacao, Brasilia (Brazil)

    1992-02-01

    Energy and technology are essential ingredients of development, it is only through their use that it became possible to sustain a population of almost 5 billion on Earth. The challenges to eradicate poverty and underdevelopment in developing countries in the face of strong population increases can only be successfully met with the use of advanced technology, leapfrogging the path followed in the past by today's industrialized countries. It is shown in the paper that energy consumption can be decoupled from economic development. Such possibility will contribute significantly in achieving sustainable development. 10 refs., 4 figs., 3 tabs.

  10. Xcode 5 developer reference

    CERN Document Server

    Wentk, Richard

    2014-01-01

    Design, code, and build amazing apps with Xcode 5 Thanks to Apple's awesome Xcode development environment, you can create the next big app for Macs, iPhones, iPads, or iPod touches. Xcode 5 contains gigabytes of great stuff to help you develop for both OS X and iOS devices - things like sample code, utilities, companion applications, documentation, and more. And with Xcode 5 Developer Reference, you now have the ultimate step-by-step guide to it all. Immerse yourself in the heady and lucrative world of Apple app development, see how to tame the latest features and functions, and find loads of

  11. Six Sigma software development

    CERN Document Server

    Tayntor, Christine B

    2002-01-01

    Since Six Sigma has had marked success in improving quality in other settings, and since the quality of software remains poor, it seems a natural evolution to apply the concepts and tools of Six Sigma to system development and the IT department. Until now however, there were no books available that applied these concepts to the system development process. Six Sigma Software Development fills this void and illustrates how Six Sigma concepts can be applied to all aspects of the evolving system development process. It includes the traditional waterfall model and in the support of legacy systems,

  12. Telemedicine for Developing Countries

    Science.gov (United States)

    Combi, Carlo; Pozzani, Gabriele

    2016-01-01

    Summary Background Developing countries need telemedicine applications that help in many situations, when physicians are a small number with respect to the population, when specialized physicians are not available, when patients and physicians in rural villages need assistance in the delivery of health care. Moreover, the requirements of telemedicine applications for developing countries are somewhat more demanding than for developed countries. Indeed, further social, organizational, and technical aspects need to be considered for successful telemedicine applications in developing countries. Objective We consider all the major projects in telemedicine, devoted to developing countries, as described by the proper scientific literature. On the basis of such literature, we want to define a specific taxonomy that allows a proper classification and a fast overview of telemedicine projects in developing countries. Moreover, by considering both the literature and some recent direct experiences, we want to complete such overview by discussing some design issues to be taken into consideration when developing telemedicine software systems. Methods We considered and reviewed the major conferences and journals in depth, and looked for reports on the telemedicine projects. Results We provide the reader with a survey of the main projects and systems, from which we derived a taxonomy of features of telemedicine systems for developing countries. We also propose and discuss some classification criteria for design issues, based on the lessons learned in this research area. Conclusions We highlight some challenges and recommendations to be considered when designing a telemedicine system for developing countries. PMID:27803948

  13. Emigration for Development?

    DEFF Research Database (Denmark)

    Careja, Romana

    2013-01-01

    is necessary if resources from emigration are to become seeds for development. By analysing the case of Romania, one of the largest labour sending countries in Eastern Europe, it argues that its laissez-faire approach is likely not enough to capitalize on emigrants' resources for development. International......This article explores the proposition that the developmental potential of emigration depends on the context of the sending countries. It builds on the insights from the institutional approach to development and adapts them to the migration-development nexus. It argues that government involvement...... Migration...

  14. Continuous Platform Development

    DEFF Research Database (Denmark)

    Nielsen, Ole Fiil

    low risks and investments but also with relatively fuzzy results. When looking for new platform projects, it is important to make sure that the company and market is ready for the introduction of platforms, and to make sure that people from marketing and sales, product development, and downstream......, but continuous product family evolution challenges this strategy. The concept of continuous platform development is based on the fact that platform development should not be a one-time experience but rather an ongoing process of developing new platforms and updating existing ones, so that product family...

  15. Population, environment and development.

    Science.gov (United States)

    Karkal, M

    1994-06-01

    Western development models label subsistence economies, which do not participate in the market economy on a grand scale and do not consume commodities produced for and distributed through the market, to be poor. Yet, subsistence does not always indicate a low quality of life. The Western development process has destroyed wholesome and sustainable lifestyles. In India, the Green Revolution caused many small farmers to lose their land. In comparison to traditional economies, industrial economies have longer technological chains dependent on higher energy and resource inputs and exclude large numbers of people without power to buy goods. Further, they generate new and artificial needs, necessitating increased production of industrial goods and services. They erode resource bases for survival. This erosion is marginalizing people who were traditionally in nature's economy. Developed countries did not deliver 0.15% of their GNP to development projects in developing countries as promised. The US made population growth in these countries its cause. The UN and other multinational agencies during 1962-1972, at the US's request, began to support population and family planning programs in developing countries. These countries opposed the 1st draft at the 1974 Bucharest Population Conference, but by the conference in Mexico City, most supported the need for family planning. Yet, the US politicized this conference and had a greater say in the recommendations than did developing countries. Structural adjustments and external debt repayments required of developing countries in the 1980s set them back. In fact, the number of developing countries increased from 31 to 42. The UN recognizes the right to development, but social inequalities are barriers to this right. If environmental degradation continues, poverty will only increase. Women's groups are playing a great role in preparations for the International Conference on Population and Development in Cairo in September 1994.

  16. EMI Registry Development Plan

    CERN Document Server

    Memon, S.; Szigeti, G.; Field, L.

    2012-01-01

    This documents describes the overall development plan of the EMI Registry product, the plan focuses on the realisation of the EMI Registry specification as defined in the document. It is understood that during the course of the development phase the specification will likely evolve and the changes will be fed into the specification document.

  17. Promoting teachers' professional development

    NARCIS (Netherlands)

    Runhaar, Pietsje Roelofje

    2008-01-01

    Because teacher quality has a great influence on pupil attainment, teachers’ professional development receives a lot of attention in educational policy. This dissertation contains five studies on how teachers’ professional development, in terms of learning at the workplace, can be explained and

  18. Counter radicalization development assistance

    OpenAIRE

    van Hippel, Karin

    2006-01-01

    The paper reviews current research and practice and recommends strategies for development agencies working in the Arab and Muslim world. It builds on the basic assumption that the realization of the Millennium Development Goals will be vital to reduce support for terrorism in the long term. Within this overall framework, emphasis is placed on particular programs that could be specifically applied to counter radicalization.

  19. Develop your presentation skills

    CERN Document Server

    Theobald, Theo

    2016-01-01

    Going beyond handling nerves and presenting PowerPoint slides, the third edition of "Develop Your Presentation Skills "offers practical advice on developing a captivating presentation, constructing compelling content, and boosting self-confidence. The book includes three new chapters on delivering a "stripped down"presentation, using new media to engage with the audience, and handling being asked to present on short notice."

  20. Trends in organization development

    NARCIS (Netherlands)

    Allegro, J.T.; Steensma, H.O.; Allegro, J.T.; Steensma, H.O.

    1985-01-01

    Organisation Development (OD) is an extraordinarly complex phenomenon of human society in which in the last few years there have been some interesting developments. Without making any claim to completeness the following topics would seem to have been a focus of interest in recent research on the

  1. Development of geothermal resources

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-09-01

    This paper describes the geothermal development promotion survey project. NEDO is taking the lead in investigation and development to reduce risks for private business entities and promote their development. The program is being moved forward by dividing the surveys into three ranks of A, B and C from prospects of geothermal resource availability and the state of data accumulation. The survey A lacks number of data, but covers areas as wide as 100 to 300 km{sup 2}, and studies possible existence of high-temperature geothermal energy. The survey B covers areas of 50 to 70 km{sup 2}, investigates availability of geothermal resources, and assesses environmental impacts. The survey C covers areas of 5 to 10 km{sup 2}, and includes production well drilling and long-term discharge tests, other than those carried out by the surveys A and B. Results derived in each fiscal year are evaluated and judged to establish development plans for the subsequent fiscal year. This paper summarizes development results on 38 areas from among 45 areas surveyed since fiscal 1980. Development promotion surveys were carried out over seven areas in fiscal 1994. Development is in progress not only on utilization of high-temperature steam, but also on binary cycle geothermal power generation utilizing hot waters of 80 to 150{degree}C. Fiscal 1994 has carried out discussions for spread and practical use of the systems (particularly on economic effects), and development of small-to-medium scale binary systems. 2 figs., 1 tab.

  2. Improvisation for Leadership Development.

    Science.gov (United States)

    Trepanier, Sylvain; Nordgren, Mollie

    2017-04-01

    Leaders are required to demonstrate agility, creativity, and innovation. Professional development educators can help leaders to develop the skills to listen carefully, be present in the moment, and contribute to any conversation by using improvisation. J Contin Educ Nurs. 2017;48(4):151-153. Copyright 2017, SLACK Incorporated.

  3. Strategic port development

    DEFF Research Database (Denmark)

    Olesen, Peter Bjerg; Dukovska-Popovska, Iskra; Steger-Jensen, Kenn

    2012-01-01

    This paper proposes a framework for strategic development of a port’s collaboration with its hinterland. The framework is based on literature relevant to port development and undertakes market perspective by considering import/export data relevant for the region of interest. The series of steps...

  4. Thermodynamics and sustainable development

    NARCIS (Netherlands)

    Cornelissen, Rene

    1997-01-01

    It is the objective of this thesis to demonstrate exergy analysis as a powerful instrument to obtain sustainable development. An important aspect of sustainable development is the minimisation of irreversibilities caused by the use of non-renewables. In order to limit the scope of this thesis

  5. concrete5 for developers

    CERN Document Server

    Uzayr, Sufyan bin

    2014-01-01

    Whether you have had some previous experience with concrete5 or are entirely new to it, this book will help you understand all that you need to know in order to get started with concrete5 development. A background in PHP is required; some knowledge of HTML/CSS is needed in order to fully grasp the concepts underlying concrete5 theme development.

  6. Developing Successful Global Leaders

    Science.gov (United States)

    Training, 2011

    2011-01-01

    Everyone seems to agree the world desperately needs strong leaders who can manage a global workforce and all the inherent challenges that go with it. That's a big part of the raison d'etre for global leadership development programs. But are today's organizations fully utilizing these programs to develop global leaders, and, if so, are they…

  7. Character Development in Adolescents.

    Science.gov (United States)

    Kessler, Glenn R.; And Others

    1986-01-01

    Explored the effects of a program consisting of communication and counseling skills, assertiveness training and moral dilemmas on the character development of high school students. The results demonstrated that the character development of the students in the experimental treatment group was affected significantly over time by the program.…

  8. International thermal reactor development

    International Nuclear Information System (INIS)

    Zebroski, E.L.

    1977-01-01

    The worldwide development of nuclear power plants is reviewed. Charts are presented which show the commitment to light-water reactor capacity construction with breakdown by region and country. Additional charts show the major nuclear research centers which have substantial scope in light water reactor development and extensive international activities

  9. Madagascar Conservation & Development

    African Journals Online (AJOL)

    Madagascar Conservation & Development welcomes the results of original research, field surveys, advances in field and laboratory techniques, book reviews, and informal status reports from research, conservation, development and management programs and in-field projects in Madagascar. In addition, notes on changes ...

  10. Hydropower development in India

    Energy Technology Data Exchange (ETDEWEB)

    Saxena, Praveen [Govt. of India, New Delhi (India). Ministry of New and Renewable Energy], E-mail: psaxena_98@yahoo.com; Kumar, Arun [Indian Institute of Technology Roorkee, Uttarakhand (India). Alternate Hydro Energy Centre], E-mail: aheciitr@gmail.com

    2011-04-15

    India is posed for large deployment of hydropower in present conducive policy and investment environment. Growing energy demand and concern for carbon emission is making hydropower development more favorable. The Government of India is ensuring a good performance of the new SHP stations by linking the incentives to the SHP developers with the performance of the station. (author)

  11. Accelerated product development

    NARCIS (Netherlands)

    Langerak, F.; Seth, J.N.; Malhotra, N.K.

    2011-01-01

    Accelerated product development is a competitive strategy that seeks to reduce the development cycle time of new products. However, there has been little theoretical advancement and empirical model testing in the identification of the conditions under which cycle time reduction is appropriate, the

  12. Global product development

    DEFF Research Database (Denmark)

    Taylor, Thomas Paul; Ahmed-Kristensen, Saeema

    2016-01-01

    Selecting key performance indicators in conventional product development is a challenging task for project management and is compound by global product development. Informed from the findings of two in depth case studies conducted with large Danish manufacturing companies, in this paper we develo...

  13. Evaluating professional development

    CERN Document Server

    Guskey, Thomas R

    2000-01-01

    This is a practical guide to evaluating professional development programs at five increasing levels of sophistication: participants' reaction to professional development; how much participants learned; evaluating organizational support and change; how participants use their new knowledge and skills; and improvements in student learning.

  14. Beijing Development Zones

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ Beijing Badaling Development Area The Development Area is planned to cover an area of 6.56 km2.Currently,more than 300 enterprises have located in the area.Their investments add up to about RMB 1 billion.Major business trades include machine building,mineral ore processing,medicine,electronic parts,foodstuff processing,and warehousing transportation.

  15. Improving Software Developer's Competence

    DEFF Research Database (Denmark)

    Abrahamsson, Pekka; Kautz, Karlheinz; Sieppi, Heikki

    2002-01-01

    Emerging agile software development methods are people oriented development approaches to be used by the software industry. The personal software process (PSP) is an accepted method for improving the capabilities of a single software engineer. Five original hypotheses regarding the impact...

  16. Youth Development: Maori Styles

    Science.gov (United States)

    Ware, Felicity; Walsh-Tapiata, Wheturangi

    2010-01-01

    Despite the innovative approach of the Youth Development Strategy Aotearoa and the applicability of its Rangatahi Development Package, the diverse realities and experiences of Maori youth are still presenting unique challenges to national policy in Aotearoa New Zealand. A Maori youth research approach that utilised a combination of action research…

  17. Fashions in Instructional Development.

    Science.gov (United States)

    Knapper, Christopher K.

    This paper on instructional development notes the trend toward teaching improvement efforts, classifies instructional development centers in terms of their differing philosophies of operation, and identifies some general problems that have been encountered in institutional efforts to improve teaching and learning. Centers in North America, Europe,…

  18. Medical device development.

    Science.gov (United States)

    Panescu, Dorin

    2009-01-01

    The development of a successful medical product requires not only engineering design efforts, but also clinical, regulatory, marketing and business expertise. This paper reviews items related to the process of designing medical devices. It discusses the steps required to take a medical product idea from concept, through development, verification and validation, regulatory approvals and market release.

  19. Financing Sustainable Development

    DEFF Research Database (Denmark)

    Fejerskov, Adam Moe; Funder, Mikkel; Engberg-Pedersen, Lars

    . But what are in fact the interests and modes of operation of such actors in the context of development financing, and to what extent do they align with the aims of the SDGs? And how do national governments of developing countries themselves perceive and approach these new sources of financing?...

  20. Culture and Development

    NARCIS (Netherlands)

    D.R. Gasper (Des)

    2006-01-01

    textabstractDiscourses on culture and development vary according to their conceptions of culture and of development and according to their standpoint. The ‘culture and development’ problematic has typically: (1) arisen from a conception of ‘culture’ as a relatively fixed, homogeneous set of mental

  1. Strategic port development

    DEFF Research Database (Denmark)

    Olesen, Peter Bjerg; Dukovska-Popovska, Iskra; Hvolby, Hans-Henrik

    2014-01-01

    While large global ports are recognised as playing a central role in many supply chains as logistic gateways, smaller regional ports have been more stagnant and have not reached the same level of development as the larger ports. The research literature in relation to port development is also...

  2. Data Centric Development Methodology

    Science.gov (United States)

    Khoury, Fadi E.

    2012-01-01

    Data centric applications, an important effort of software development in large organizations, have been mostly adopting a software methodology, such as a waterfall or Rational Unified Process, as the framework for its development. These methodologies could work on structural, procedural, or object oriented based applications, but fails to capture…

  3. New Services Development

    Directory of Open Access Journals (Sweden)

    Peter Ciganek

    2004-01-01

    Full Text Available Dynamic changes in traditional technologies and rising of new technologies call for development of new services. If service providers want to stay on information technologies market, they must keep track with this trend and adjust their services to customer requirements or develop new services. New applications will mainly depend on communication bandwidth and end users ability to handle it. If network providers will be able to ensure necessary bandwidth, there will be nothing that can stop service providers and developers in new service development. People know about growing necessity of new service and ask for them, but they hardly understand that the most important thing for service providers is merchantability and economic return of resources they gave to the developmentand implementation. By the lack of flexible development environment that is able to develop, test and provide final service for operation, new service development is not easy. There are different new service design procedures for various technological and user areas. This is the reason why this paper provides brief description of new service development procedure from technological and administrative point of view.

  4. Standards and Professional Development

    Science.gov (United States)

    Zengler, Cynthia J.

    2017-01-01

    The purpose of this paper is to describe the professional development that has taken place in conjunction with Ohio adopting the College and Career Readiness (CCR) Standards. The professional development (PD) has changed over time to include not only training on the new standards and lesson plans but training on the concepts defined in the…

  5. Law, Democracy & Development

    African Journals Online (AJOL)

    The evolution and implementation of democracy, good governance practices, human rights and socio-economic development are critical issues facing South Africa and Africa as a whole. Law interacts with this process in ways that may promote or inhibit it. Law, Democracy & Development addresses this interaction. Our aim ...

  6. Media and child development

    NARCIS (Netherlands)

    Piotrowski, J.T.; Vossen, H.G.M.; Valkenburg, P.M.; Wright, J.D.

    2015-01-01

    Decades of research have shown that the relationship between media and childhood is not unidirectional but reciprocal. In this article, both directions of the media-child development relationship are presented. We discuss how child development predisposes children's media use and preferences by

  7. Globalization, consumption, development

    NARCIS (Netherlands)

    Binsbergen, van W.M.J.; Fardon, R.; Binsbergen, van W.M.J.; Dijk, van R.A.

    1999-01-01

    The papers collected in this volume were first presented at a conference on 'Globalization, development and the making of consumers: what are collective identities for?' which was held in The Hague, The Netherlands, on 13-16 March 1997. The papers are concerned with the challenge to the development

  8. Microsoft Azure development cookbook

    CERN Document Server

    Freato, Roberto

    2014-01-01

    If you are an architect, this book will help you make the correct decisions about which Azure building blocks to use. If you are a developer, this book will help you understand how to use them appropriately, and if you are a .NET developer, this book is a pure delight.

  9. Centrifugal analyzer development

    International Nuclear Information System (INIS)

    Burtis, C.A.; Bauer, M.L.; Bostick, W.D.

    1976-01-01

    The development of the centrifuge fast analyzer (CFA) is reviewed. The development of a miniature CFA with computer data analysis is reported and applications for automated diagnostic chemical and hematological assays are discussed. A portable CFA system with microprocessor was adapted for field assays of air and water samples for environmental pollutants, including ammonia, nitrates, nitrites, phosphates, sulfates, and silica. 83 references

  10. ENTERPRISES DEVELOPMENT: MANAGEMENT MODEL

    Directory of Open Access Journals (Sweden)

    Lina Shenderivska

    2018-01-01

    Full Text Available The paper’s purpose is to provide recommendations for the effective managing the companies’ development taking into account the sectoral key elements’ transformation. Methodology. The enterprise profits’ econometric simulation is conducted to determine the most significant factors influencing their development. According to the model testing result, their multicollinearity was revealed. To get rid of the multicollinearity phenomenon from the profit models, isolated regressors are excluded, namely, return on assets, material returns, return on equity. To obtain qualitative models with a small error of model parameters estimation and, accordingly, high reliability of the conclusion about the interrelation between the factors of the model and the resulting feature, factors in the income model that are not closely interconnected, that is, not multicollinear, are included. Determination coefficients R2 and F-criterion were calculated for model quality checking. The modern printing enterprises of Ukraine key elements, connected with integration into the global information space, are analysed. Results. The interrelation between a company’s development and earning capacity is identified in the study. The profit importance as the main source for enterprise financing is substantiated. Factors that have the greatest impact on the enterprises’ development are labour productivity, financial autonomy, working capital turnover, and the character of their influence is most adequately reflected by the power model. Peculiarities of the enterprises’ activity include increased competition at the inter-branch level, poorly developed industrial relations, and the own sources of financing activities shortage. Practical implications. Based on information on the most significant developmental impact factors, directions for perspective enterprises development for their competitiveness increase are proposed: diversification based on the activity expansion

  11. Finance and Economic Development

    Directory of Open Access Journals (Sweden)

    Ugo Panizza

    2012-03-01

    Full Text Available Published by Palgrave MacmillanThis chapter reviews the literature on finance and economic development. It starts with a description of the roles of finance, a definition of financial efficiency, and a discussion of whether countries may have financial sectors that are ‘too large’ compared to the size of the domestic economy. Next, the author describes several indicators of financial development and reviews the literature on the relationship between financial development and economic growth. In the literature review, he discusses in detail some recent evidence indicating that the marginal contribution of financial development to gross domestic product (GDP growth becomes negative when credit to the private sector reaches 110 per cent of GDP. The chapter concludes with some policy conclusions targeted to developing countries.

  12. Development concept plan

    International Nuclear Information System (INIS)

    1992-06-01

    The following management objectives for New River Gorge National River relate to the Kaymoor site to: Preserve coal mining, railroad, and other historic resources that best illustrate park significance; Develop a system of land- and water-based recreation opportunities that allow visitors to experience the park's resources to the extent that natural, cultural, and scenic values are not imparied; and Work with the community to the extent possible to help it maximize economic benefits related to park development without impairing key resources. The Development Concept Plant outlining a plan of development for Kaymoor is a part of a larger emphasis by the National Park Service to identify and develop significant coal-related historic and cultural resources in southern West Virginia in cooperation with the West Virginia State Historic Preservation Office

  13. Urban Quality Development & Management

    DEFF Research Database (Denmark)

    Lehmann, Martin; Fryd, Ole

    2008-01-01

    Purpose: The purpose of this article is to describe and discuss the development and the structure of a new international master on the subject of Urban Quality Development & Management, and explore the potential of the process and the outcome in serving as models adoptable by faculty at other......: Urban quality development and management is dependent on human resource development, institutionalised networks and confident exchange of knowledge, and must identify and incorporate multiple environmental, social, economic and cultural aspects. The authors find that at the core of innovative societies......, an interlinkage exists between practice (business, civil society, governance) and theory (research, education). The case illustrates how a new curriculum takes time to develop and implement and how it relies on confidence and trust between partners, in this case cities and universities, before being able to plant...

  14. Environment: Development plan 1993

    International Nuclear Information System (INIS)

    1992-01-01

    The concept of sustainable development is gradually being incorporated into the activities of Hydro-Quebec as part of that utility's environmental policy. In its proposed development plan, Hydro-Quebec's principal strategic environmental orientations comprise making environmental concerns an integral part of the planning process, managing impacts associated with the construction of generating and transmission facilities, and evaluating the utility's environmental performance. The approaches used, tools to be developed, and information required in each of these orientations are described. Issues considered include the strategic choices available for meeting electricity requirements, including renewable energy sources; the evaluation of environmental externalities; the use of environmental impact assessment studies and environmental monitoring; relationships with native peoples and mitigation of the social impacts of northern hydroelectric development; protection and management of natural and human habitats; the utility's contribution to regional development; management of wastes and rights-of-way; and environmental auditing. 1 tab

  15. Global product development

    DEFF Research Database (Denmark)

    Hansen, Zaza Nadja Lee; Ahmed-Kristensen, Saeema

    2011-01-01

    Globalisation has enabled companies to globalise their product development process. Today, everything from manufacturing to R&D can be globally distributed. This has led to a more complex and disintegrated product development process. This paper investigates the impacts companies have experienced...... operational solutions to counteract the negative impacts with varying degrees of success. This paper presents a unique look into global product development through an investigation of its impact on the organisation, the product development process, and the product. Furthermore, it shows the solutions...... as a result of this, and how they have been addressed. Data was collected through case studies of five Danish multinational corporations. The findings showed that the companies experienced several challenges when they globalised their product development process. They consequently implemented various...

  16. An Fgf-Shh signaling hierarchy regulates early specification of the zebrafish skull.

    Science.gov (United States)

    McCarthy, Neil; Sidik, Alfire; Bertrand, Julien Y; Eberhart, Johann K

    2016-07-15

    The neurocranium generates most of the craniofacial skeleton and consists of prechordal and postchordal regions. Although development of the prechordal is well studied, little is known of the postchordal region. Here we characterize a signaling hierarchy necessary for postchordal neurocranial development involving Fibroblast growth factor (Fgf) signaling for early specification of mesodermally-derived progenitor cells. The expression of hyaluron synthetase 2 (has2) in the cephalic mesoderm requires Fgf signaling and Has2 function, in turn, is required for postchordal neurocranial development. While Hedgehog (Hh)-deficient embryos also lack a postchordal neurocranium, this appears primarily due to a later defect in chondrocyte differentiation. Inhibitor studies demonstrate that postchordal neurocranial development requires early Fgf and later Hh signaling. Collectively, our results provide a mechanistic understanding of early postchordal neurocranial development and demonstrate a hierarchy of signaling between Fgf and Hh in the development of this structure. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  17. The development of colliders

    International Nuclear Information System (INIS)

    Sessler, A.M.

    1993-02-01

    Don Kerst, Gersh Budker, and Bruno Touschek were the individuals, and the motivating force, which brought about the development of colliders, while the laboratories at which it happened were Stanford, MURA, the Cambridge Electron Accelerator, Orsay, Frascati, CERN, and Novosibirsk. These laboratories supported, during many years, this rather speculative activity. Of course, many hundreds of physicists contributed to the development of colliders but the men who started it, set it in the right direction, and forcefully made it happen, were Don, Gersh, and Bruno. Don was instrumental in the development of proton-proton colliders, while Bruno and Gersh spearheaded the development of electron-positron colliders. In this brief review of the history, I will sketch the development of the concepts, the experiments, and the technological developments which made possible the development of colliders. It may look as if the emphasis is on theoretical concepts, but that is really not the case, for in this field -- the physics of beams -- the theory and experiment go hand in hand; theoretical understanding and advances are almost always motivated by the need to explain experimental results or the desire to construct better experimental devices

  18. A new development agenda.

    Science.gov (United States)

    Sadik, N

    1992-01-01

    The successful report of the UN Commission on Environment and Development and the Earth Summit demonstrate the strong potential of making future concerted strides toward sustainable development. The process pointed out how social injustice prevents economic and political development and emphasize the need to eradicate extreme poverty, poor health, illiteracy, unwanted high fertility, and the oppression of women. The middle classes must also be aided and the burden on the environment reduced in the attempt to achieve sustainable development. Human-centered development is the basis of sustainable development and is capable of reducing poverty and population pressures. Agenda 21 details links between population, environment, development, and international responsibility. While honoring the rights of individuals to freely choose among reproductive options, international policymakers should agree to keep overall population growth within or slightly below the medium projection of 6.2 billion by the end of the century, 10 billion by mid-century, and eventually 11 billion. By the end of the century, it is also hoped that the number of couples using family planning will increase by 50%, marriage age will increase, teen pregnancy and maternal and infant mortality will be reduced, and resources devoted to population programs will double.

  19. Pipeline for Contraceptive Development

    Science.gov (United States)

    Blithe, Diana L.

    2016-01-01

    The high rates of unplanned pregnancy reflect unmet need for effective contraceptive methods for women, especially for individuals with health risks such as obesity, diabetes, hypertension, and other conditions that may contraindicate use of an estrogen-containing product. Improvements in safety, user convenience, acceptability and availability of products remain important goals of the contraceptive development program. Another important goal is to minimize the impact of the products on the environment. Development of new methods for male contraception has the potential to address many of these issues with regard to safety for women who have contraindications to effective contraceptive methods but want to protect against pregnancy. It also will address a huge unmet need for men who want to control their fertility. Products under development for men would not introduce eco-toxic hormones in the waste water. Investment in contraceptive research to identify new products for women has been limited in the pharmaceutical industry relative to investment in drug development for other indications. Pharmaceutical R&D for male contraception was active in the 1990’s but was abandoned over a decade ago. The Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) has supported a contraceptive development program since 1969. Through a variety of programs including research grants and contracts, NICHD has developed a pipeline of new targets/products for male and female contraception. A number of lead candidates are under evaluation in the NICHD Contraceptive Clinical Trials Network (CCTN) (1–3). PMID:27523300

  20. Transdisciplinary product development

    Directory of Open Access Journals (Sweden)

    Tomaž Savšek

    2015-12-01

    Full Text Available Research Question (RQ: How can transdisciplinary approach increase the product development process in future industry? Purpose: The aim of the research is to develop a model of an effective product development in the automotive industry based on the transdisciplinary approach. Method: We used a qualitative research approach in order to develop a theoretical framework of transdisciplinarity. The framework comprises the concurrent engineering and experts from different disciplines. The framework was represented by a mathematical model which based on stochastic dynamic programming. Results: We developed a theoretical frameworkand a practical case of transdisciplinary product development in the automotive industry. We presented a mathematical model and information environment which supports such a model. Organization: The findings of the research will provide higher productivity, lower operating costs, change in personnel structure, higher added value, lower sales costs, lower administration costs, reduction in growth of expenses, and lower costs of work equipment. Society: The research impact on higher customer’s satisfaction, increased flexibility of operations, better quality of information, improved control of sources, less waste materials and less pollution, improved planning process, more favourable consideration of employees , improved portfolio management, and better corporate presentation of company. Originality: Transdisciplinary framework combines methods of concurrent engineering and interdisciplinary approach in a process of product development. The development of such a framework is a complete novelty and represents an original approach to product development, which will be particularly suitable for the smart factories of the future. Transdisciplinary framework was transformed in to a mathematical model based on stochastic dynamic programming. Model is supported by the existing information warehouse and represents a potential for

  1. Agile software development

    CERN Document Server

    Stober, Thomas

    2009-01-01

    Software Development is moving towards a more agile and more flexible approach. It turns out that the traditional 'waterfall' model is not supportive in an environment where technical, financial and strategic constraints are changing almost every day. But what is agility? What are today's major approaches? And especially: What is the impact of agile development principles on the development teams, on project management and on software architects? How can large enterprises become more agile and improve their business processes, which have been existing since many, many years? What are the limit

  2. Piezoelectric Accelerometers Development

    DEFF Research Database (Denmark)

    Liu, Bin; Bang, Lisbet Fogh

    1999-01-01

    The paper describes the development of piezoelectric accelerometers using Finite Element (FE) approach. Brüel & Kjær Accelerometer Type 8325 is chosen as an example to illustrate the advanced accelerometer development procedure. The deviation between simulated results and measured results of Type...... 8325 are below 6%. It is proved that the specifications of the accelerometer can be effectively predicted using the FE method, especially when modifications of the accelerometer are required. The development process of piezoelectric accelerometers in Brüel & Kjær is becoming more efficient...

  3. Piezoelectric accelerometeres development

    DEFF Research Database (Denmark)

    Liu, Bin

    1999-01-01

    The paper describes the development of piezoelectric accelerometers using Finite Element (FE) approach. Brüel & Kjær Accelerometer Type 8325 is chosen as an example to illustrate the advanced accelerometer development procedure. The deviation between simulated results and measured results of Type...... 8325 are below 6%. It is proved that the specifications of the accelerometer can be effectively predicted using the FE method, especially when modifications of the accelerometer are required. The development process of piezoelectric accelerometers in Brüel & Kjær is becoming more efficient....

  4. Community development planning

    International Nuclear Information System (INIS)

    Gray, S.I.

    1983-01-01

    The focus of this paper will be methods of local community involvement in the community development planning efforts which will be required at the recommended sites. Community development planning will include capital improvement plans, housing plans, zoning changes, business development plans and other community service and fiscal plans required to meet the projected needs of new residents as a result of the repository construction and operation. This paper will present, (1) the need for community planning, (2) methods of responding to community planning needs, (3) current community planning issues to be addressed. 2 references, 1 figure

  5. The sustainable development

    International Nuclear Information System (INIS)

    Robreau, Y.; Porcher, P.

    2002-11-01

    This document aims to define the sustainable development concept with a special attention for France and Israel position. The first part recalls the history of the sustainable development from the ''Man and Biosphere'' program of the UNESCO to Rio protocol. Then are described the principles of the sustainable development, the France plans and the France position at Johannesburg conference. The last part is devoted to the Israel position and a short presentation of the consequences of the greenhouse gases on the human health and the environment. (A.L.B.)

  6. Beginning Nokia Apps Development

    CERN Document Server

    Rischpater, Ray

    2010-01-01

    While media buzz regularly circulates around iPhone and Android, Nokia still leads the pack in terms of world market share. Symbian, for instance, remains the most widely used mobile operating system. With Nokia's open development platform, the opportunities available for mobile developers to target this vastly popular operating system are abundant and clear. * Use Qt to target both platforms: Symbian, the most widely used mobile operating system in the world, as well as MeeGo, the Intel/Nokia platform for mobile devices. * Develop HTML5 applications for both Symbian and MeeGo platforms that w

  7. Materials development for TESOL

    CERN Document Server

    Mishan, Freda

    2015-01-01

    Materials development has become much more important in the field of TESOL in the last twenty years: modules on materials development are now commonplace on MA TESOL courses around the world. The overall aim of the book is to introduce readers to a wide range of theoretical and practical issues in materials development to enable them to make informed and principled choices in the selection, evaluation, adaptation and production of materials. The book aims to show how these choices need to be informed by an awareness of culture, context and purpose.

  8. Textile technology development

    Science.gov (United States)

    Shah, Bharat M.

    1995-01-01

    The objectives of this report were to evaluate and select resin systems for Resin Transfer Molding (RTM) and Powder Towpreg Material, to develop and evaluate advanced textile processes by comparing 2-D and 3-D braiding for fuselage frame applications and develop window belt and side panel structural design concepts, to evaluate textile material properties, and to develop low cost manufacturing and tooling processes for the automated manufacturing of fuselage primary structures. This research was in support of the NASA and Langley Research Center (LaRc) Advanced Composite Structural Concepts and Materials Technologies for Primary Aircraft Structures program.

  9. Developing students’ entrepreneurial spirit

    Directory of Open Access Journals (Sweden)

    Grădinaru, E.

    2012-01-01

    Full Text Available This paper contains a research study about the necessity to develop the entrepreneurial spirit in universities and how students could be involved in such initiatives. A qualitative research based on three focus groups was conducted, having as main objective to identify students’ opinions regarding the initiative to develop an on-line magazine for students and young people. The results reveal that students prefer the online media to the traditional ones and the pilot numbers of the magazine received good appreciations. A business plan for the future development of the magazine is also presented.

  10. Tracking Your Development

    CERN Document Server

    Hennum, Kelly M

    2011-01-01

    This book provides you with the means to set development goals and to track your progress on achieving them. It can help you efficiently gather and make sense of information about your progress and avoid common pitfalls that can block your development. Tracking your development can be captures in a few steps: articulating your goal, creating an action plan, gathering information about your behavior, indentifying barriers and support, and revising your action plan. Taking these steps will greatly increase the likelihood of achieving your goals.

  11. Development without a metropolis

    DEFF Research Database (Denmark)

    Monsson, Christian Kjær

    2014-01-01

    to the universal advice replete in some types of place-based development guidelines and literature. The paper consequently formulates propositions about beneficial practices for the development of non-metropolitan territories. The essence of these is that non-metropolitan regions can benefit from initiatives...... focusing on the management capabilities of a broad set of regional companies rather than pursuing industry-specific ‘smart’ specialisation strategies. These initiatives can include alternative models for learning and knowledge development based on shared challenges rather than industrial relatedness...

  12. Leap Motion development essentials

    CERN Document Server

    Spiegelmock, Mischa

    2013-01-01

    This book is a fast-paced guide with practical examples that aims to help you understand and master the Leap Motion SDK.This book is for developers who are either involved in game development or who are looking to utilize Leap Motion technology in order to create brand new user interaction experiences to distinguish their products from the mass market. You should be comfortable with high-level languages and object-oriented development concepts in order to get the most out of this book.

  13. Laser Cutting, Development Trends

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove

    1999-01-01

    In this paper a short review of the development trends in laser cutting will be given.The technology, which is the fastest expanding industrial production technology will develop in both its core market segment: Flat bed cutting of sheet metal, as it will expand in heavy industry and in cutting...... of 3-dimensional shapes.The CO2-laser will also in the near future be the dominating laser source in the market, although the new developments in ND-YAG-lasers opens for new possibilities for this laser type....

  14. Neutral beam development plan

    International Nuclear Information System (INIS)

    Staten, H.S.

    1980-08-01

    The national plan is presented for developing advanced injection systems for use on upgrades of existing experiments, and use on future facilities such as ETF, to be built in the late 1980's or early 90's where power production from magnetic fusion will move closer to a reality. Not only must higher power and longer pulse length systems be developed , but they must operate reliably; they must be a tool for the experimenter, not the experiment itself. Neutral beam systems handle large amounts of energy and as such, they often are as complicated as the plasma physics experiment itself. This presents a significant challenge to the neutral beam developer

  15. Developing Bigraphical Languages

    DEFF Research Database (Denmark)

    Damgaard, Troels Christoffer

    In this dissertation, we study bigraphical languages—languages based on the theory for bigraphs and bigraphical reactive systems developed by Milner and coworkers. We begin by examining algebraic theory for binding bigraphs. We give a term language for binding bigraphs and develop a complete......, a prototype tool for experimenting with bigraphical reactive systems. In a second line of work, we study bigraphical reactive systems as a vehicle for developing a language to model biochemical reactions at the level of cells and proteins. We discuss and isolate B,R-calculi, a family of bigraphical reactive...

  16. Industrialized Information Systems Development

    DEFF Research Database (Denmark)

    Havn, Erling; Bansler, Jørgen P.

    1996-01-01

    The production of application software is rapidly being industrialized. Computer manufacturers and software houses produce a rapidly growing number of generic software applications and systems, and more and more user companies choose to build their computer-based information systems...... with such generic products, instead of custom made software. We discuss how the move away from traditional in-house development and the increasing use of generic software is likely to transform IS development in the near future. We conclude that these developments will make new demands on the information systems...

  17. Inequality, poverty and development.

    Science.gov (United States)

    Ahluwalia, M S

    1976-12-01

    Dicussion explores the nature of the relationship between the distribution of income and the process of development on the basis of cross country data on income inequality. The results presented are based on a sample of 60 countries, including 40 developing countries, 14 developed countries, and 6 socialist countries. The approach adopted is essentially exploratory. Multivariate regression analysis was used to estimate cross country relationships between the income shares of different percentile groups and selected variables reflecting aspects of the development process which are likely to influence income inequality. The estimated equations are then used as a basis for broad generalizations about the relationship between income distribution and development. There was strong support for the proposition that relative inequaltiy increases substantially in the early stages of development, with a reversal of this tendency in the later stages. The propositions held whether the sample was restricted to developing countries or expanded to include developed and socialist countries. The process was most prolonged for the poorest group. There were a number of processes occurring "pari passu" with development which were correlated with income inequality and which can plausibly be interpreted as causal. These were intersectoral shifts in the structure of production, expansion in education attainment and skill level of the labor force; and reduction in the growth of population. The operation of these processes appeared to explain some of the improvement in income distribution observed in the later stages of development, but they did not serve to explain the marked deterioration observed in the earlier stages. The cross section results failed to support the stronger hypothesis that the deterioration in relative inequality reflected a prolonged absolute impoverishment of large sections of the population in the course of development. The cross country pattern showed average

  18. JBoss AS 7 development

    CERN Document Server

    Marchioni, Francesco

    2013-01-01

    This book will kick-start your productivity and help you to master JBoss AS development. The author's experience with JBoss enables him to share insights on JBoss AS development in a clear and friendly way. By the end of the book, you will have the confidence to apply all the newest programming techniques to your JBoss applications.If you are a Java architect or developer who wants to get the most out of the latest release of the JBoss application server, then this book is for you. You are not expected to have accumulated experience on the application server though you must know the basic conc

  19. Professional mobile application development

    CERN Document Server

    McWherter, Jeff

    2012-01-01

    Create applications for all major smartphone platforms Creating applications for the myriad versions and varieties of mobile phone platforms on the market can be daunting to even the most seasoned developer. This authoritative guide is written in such as way that it takes your existing skills and experience and uses that background as a solid foundation for developing applications that cross over between platforms, thereby freeing you from having to learn a new platform from scratch each time. Concise explanations walk you through the tools and patterns for developing for all the mobile platfo

  20. Developing Effective Performance Measures

    Science.gov (United States)

    2014-10-14

    University When Performance Measurement Goes Bad Laziness Vanity Narcissism Too Many Pettiness Inanity 52 Developing Effective...Kasunic, October 14, 2014 © 2014 Carnegie Mellon University Narcissism Measuring performance from the organization’s point of view, rather than from