Search results for "Generation"
showing 10 items of 3050 documents
A Smoothed Particle Image Reconstruction method
2010
Many image processing techniques work with scattered data distribution usually employing grid based methods leading to numerical problems. To address this issue, a numerical method avoiding mesh generation can be used. Such a method performs an integral representation by means of a smoothing kernel function and, in the discrete formulation, involves domain particles. In this paper the meshless Smoothed Particle Hydrodynamics method is proposed in the Image Reconstruction context and a new computational strategy called Smoothed Particle Image Reconstruction is presented; the new method is based on a scatter approach and several innovative ideas are introduced in order to improve the computat…
Restitutionserscheinungen an pflanzlichen Meristemen nach Röntgenbestrahlung
1964
Young undifferentiated embryos ofEranthis hiemalis were treated with x-rays (1000–4000 r) and their further development was observed. In most of the 4000 r-group the division-activity is completely and irreversibly arrested, but the cell image remains unchanged. The embryos treated with doses between 1000 and 2000 r are also severely damaged, this time undergoing radical disorganization of the tissue, due to degeneration and necrosis. In these embryos small cell groups or even single cells are able to regain their mitotic potency. Meristematic centers (“embryoids”) arise and develop into normal or sometimes misformed viable adventive embryos. This restitution takes place only in x-rayed emb…
Optical characterization of YCa4O(BO3)3 and Nd:YCa4O(BO3)3 crystals
2007
International audience; We report a complete optical characterization of YCa4O(BO3)3 and Nd:YCa4O(BO3)3 crystals. We studied the relative orientation between the dielectric and the crystallographic frames as a function of the wavelength and performed accurate phase-matching angles measurements for second harmonic generation, using a single crystal cut as a sphere. We also recorded polarized luminescence spectra of Nd:YCOB along the principal axes of the dielectric frame. For both crystals, we measured the gray-tracking and the thermo-optic properties as a function of temperature and wavelength using oriented slabs. Finally, we measured all their dielectric and electro-optic coefficients, as…
The effect of intracavernosal growth differentiation factor-5 therapy in a rat model of cavernosal nerve injury.
2006
OBJECTIVE To determine whether the intracavernosal application of growth differentiation factor-5 (GDF-5) influences nerve regeneration and erectile function after cavernosal nerve injury in a rat model. MATERIALS AND METHODS Thirty-two male Sprague-Dawley rats were randomly divided into four equal groups: eight had a sham operation (uninjured controls), while 24 had bilateral cavernosal nerve crush. The crush-injury groups were treated at the time of injury with an impregnated collagen sponge implanted into the right corpus cavernosum. The sponge contained no GDF-5 (injured controls), 2 µg (low concentration), or 20 µg GDF-5 (high concentration). Erectile function was assessed by cavernosa…
The fine structure of de-and reinnervated muscle spindles
1974
Reinnervated muscle spindles in lower lumbrical muscles of rats studied 17 days to 24 months after crushing the sciatic nerve showed a series of alterations which have not been analysed, thus far, by electron microscopy. There was a striking increase of the number of intrafusal muscle fibers seen in approximately 20% of reinnervated spindles. These spindles showed 5–11 intrafusal muscle fibers whereas normal spindles usually contained 3–4 fibers only.
Mitochondrial defects and neuromuscular degeneration caused by altered expression of Drosophila Gdap1: implications for the Charcot–Marie–Tooth neuro…
2014
One of the genes involved in Charcot-Marie-Tooth (CMT) disease, an inherited peripheral neuropathy, is GDAP1. In this work, we show that there is a true ortholog of this gene in Drosophila, which we have named Gdap1. By up- and down-regulation of Gdap1 in a tissue-specific manner, we show that altering its levels of expression produces changes in mitochondrial size, morphology and distribution, and neuronal and muscular degeneration. Interestingly, muscular degeneration is tissue-autonomous and not dependent on innervation. Metabolic analyses of our experimental genotypes suggest that alterations in oxidative stress are not a primary cause of the neuromuscular degeneration but a long-term c…
The role of glia, mitochondria, and the immune system in glaucoma.
2009
Author(s): Tezel, Gulgun; Fourth ARVO/Pfizer Ophthalmics Research Institute Conference Working Group
Glial and neuronal expression of polyglutamine proteins induce behavioral changes and aggregate formation inDrosophila
2004
Patients with polyglutamine expansion diseases, like Huntington's disease or several spinocerebellar ataxias, first present with neurological symptoms that can occur in the absence of neurodegeneration. Behavioral symptoms thus appear to be caused by neuronal dysfunction, rather than cell death. Pathogenesis in polyglutamine expansion diseases is largely viewed as a cell-autonomous process in neurons. It is likely, however, that this process is influenced by changes in glial physiology and, at least in the case of DRPLA glial inclusions and glial cell death, seems to be an important part in the pathogenesis. To investigate these aspects in a Drosophila model system, we expressed polyglutami…
Wrapping it up: the cell biology of myelination.
2007
During nervous system development, oligodendroglia in the central nervous system (CNS) and Schwann cells in the peripheral nervous system (PNS) synthesise large amounts of specific proteins and lipids to generate myelin, a specialised membrane that spirally ensheathes axons and facilitates fast conduction of the action potential. Myelination is initiated after glial processes have attached to the axon and polarisation of the plasma membrane has been triggered. Myelin assembly is a multi-step process that occurs in spatially distinct regions of the cell. We propose that assembly of myelin proteins and lipids starts during their transport through the biosynthetic pathway and continues at the …
Glial precursors clear sensory neuron corpses during development via Jedi-1, an engulfment receptor
2009
During the development of peripheral ganglia, 50% of the neurons that are generated undergo apoptosis. How the massive numbers of corpses are removed is unknown. We found that satellite glial cell precursors are the primary phagocytic cells for apoptotic corpse removal in developing mouse dorsal root ganglia (DRG). Confocal and electron microscopic analysis revealed that glial precursors, rather than macrophages, were responsible for clearing most of the dead DRG neurons. Moreover, we identified Jedi-1, an engulfment receptor, and MEGF10, a purported engulfment receptor, as homologs of the invertebrate engulfment receptors Draper and CED-1 expressed in the glial precursor cells. Expression …