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Elongated Morphology (elongated + morphology)
Selected AbstractsA radialization factor in normal cortical plate restores disorganized radial glia and disrupted migration in a model of cortical dysplasiaEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2003Thomas A. Hasling Abstract Treatment of pregnant ferrets on embryonic day 24 (E24) with the antimitotic methylazoxy methanol (MAM) leads to a specific constellation of effects in newborn kits, which include a very thin and poorly laminated neocortex, disruption of radial glial cell morphology with early differentiation into astrocytes, and abnormal positioning of Cajal,Retzius cells. We suggest that MAM treatment on E24 results in this model of cortical dysplasia by eliminating a population of cells that produce a factor capable of maintaining radial glia in their normal morphology. The abnormal radial glia, either alone or in combination with other abnormal features, are likely to prevent proper migration into the cortical plate. To test the possibility that normal cortex can provide the missing substance that influences radial glia, slices of E24 MAM-treated cortex were removed at postnatal day 0 (P0) and cultured adjacent to explants of P0 normal cortical plate. By labelling a small number of cells with injections of fluorescent dextrans into the cultured slices, we found that abnormal radial glia in MAM treated slices cocultured adjacent to normal cortical plate were restored toward normal, in comparison to E24 MAM treated slices cultured alone and in other control conditions. We also found that abnormally positioned Cajal,Retzius cells move into the marginal zone and that neurons are able to migrate into the cortical plate more effectively in the coculture condition. These data indicate that normal cortical plate of ferrets contains a factor causing radial glia to maintain their elongated morphology; the improved position of radial glia encourages repositioning of Cajal,Retzius cells and improved neuronal migration into the cortical plate. [source] Magnetic-Field-Assisted Electrospinning of Aligned Straight and Wavy Polymeric NanofibersADVANCED MATERIALS, Issue 22 2010Yaqing Liu Aligned straight and wavy fibers of biodegradable poly(D,L-lactic- co -glycolic acid) (PLGA) are fabricated using a magnetic-field-assisted electrospinning method. PLGA fibrous matrices prepared by this method can guide the growth of pluripotent murine mesenchymal stem cells. While the stem cells on the randomly oriented fibers adapt pseudo-sphere-like shape, those on aligned fibers exhibit elongated morphology along the long axes (see figure). [source] Investigation of the phase morphology of dynamically vulcanized PVC/NBR blends using atomic force microscopyJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010S. M. Gheno Abstract Dynamic vulcanization is a mixing process employed in the melt state of elastomers with thermoplastics. This process may result in the formation of thermoplastic vulcanized (TPV) materials with improved properties such as mechanical strength, Young's modulus, hardness, and abrasion fatigue. In this study, a vulcanized thermoplastic was obtained by the dynamic vulcanization of poly(vinyl chloride)/acrylonitrile butadiene rubber (PVC/NBR) blends using a curative system based on sulfur (S)/tetramethylthiuram disulfide (TMTD) and mercaptobenzothiazyl disulfide (MBTS). The formation of crosslinks was characterized by differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy. The mechanical properties were analyzed by tensile tests and the phase morphology was investigated using atomic force microscopy (AFM) operating in the tapping mode-AFM. The phase images of the dynamically vulcanized blends showed an elongated morphology, which can be associated to the formation of crosslinks that give the material its excellent mechanical properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] INORGANIC CARBON REPLETION DISRUPTS PHOTOSYNTHETIC ACCLIMATION TO LOW TEMPERATURE IN THE CYANOBACTERIUM SYNECHOCOCCUS ELONGATUS,JOURNAL OF PHYCOLOGY, Issue 2 2005Robert A. Burns Acclimation of cyanobacteria to ambient fluctuations in inorganic carbon (Ci) and temperature requires reorganization of the major protein complexes involved in photosynthesis. We grew cultures of the picoplanktonic cyanobacterium Synechococcus elongatus Naegeli across most of its range of tolerable temperatures from 23 to 35°C at both low (<0.1 mM) and high Ci (approximately 4 mM). Over that range of temperatures, the chl-based doubling time did not differ between low and high Ci grown cells but did increase with decreasing temperature. Cells grown at 23°C high Ci showed an elongated morphology, which was not present in 23°C low Ci cells nor at 35°C high and low Ci. Furthermore, 23°C high Ci cells showed premature senescence and death compared with all other treatments. Phycocyanin per cell was greater in high Ci grown cells at all temperatures but showed a characteristic decrease with decreasing temperature. Functional PSII determination showed that 23°C high Ci cells had 1.5 × 105 PSII·cell,1 compared with only 6.9 × 104 PSII·cell,1 for 23°C low Ci. The 35°C high and low Ci cells had 7.7 × 104 and 6.4 × 104 PSII·cell,1, respectively. These data were supported by immunoblot determinations of PsbA content·cell,1. As a result of their high PSII·cell,1, 23°C high Ci cells generated more reductant from PSII than could be accommodated by downstream assimilative metabolism, resulting in early senescence and death of 23°C high Ci cells, probably as a result of the generation of reactive byproducts of electron transport. [source] Three-dimensional hydrodynamical simulations of the large-scale structure of W50,SS433MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 2 2008Jesús Zavala ABSTRACT We present 3D hydrodynamical simulations of a precessing jet propagating inside a supernova remnant (SNR) shell, particularly applied to the W50,SS433 system in a search for the origin of its peculiar elongated morphology. Several runs were carried out with different values for the mass-loss rate of the jet, the initial radius of the SNR, and the opening angle of the precession cone. We found that our models successfully reproduce the scale and morphology of W50 when the opening angle of the jets is set to 10° or if this angle linearly varies with time. For these models, more realistic runs were made considering that the remnant is expanding into an interstellar medium with an exponential density profile (as H i observations suggest). Taking into account all these ingredients, the large-scale morphology of the W50,SS433 system, including the asymmetry between the lobes (formed by the jet,SNR interaction), is well reproduced. [source] | |||||||||||||