NULL

NULL

NULL

NULL

NULL

NULL

NULL

NULL

The ultrastructure of muscle dedifferentiation and redifferentiation was observed during hind limb regeneration in a larval stage (number 53) of Bufo regularis. It was found that the young, forming muscle fibres with low level of differentiation, can easily loose its morphological characteristic features and dedifferentiate into blastemal cells from which new muscle fibres redifferentiate. Dedifferentiated cells were acquiring characteristics of actively growing cells reflecting their transformation into blastemal mesenchyme cells and then into redifferentiated muscle fibres. Satellite cells were not observed in the formation of the new myotubes. The absence of satellite cells in muscle fibres, in the present study, was suggested to be due to the low level of differentiation of muscle fibres, since the observed cells were either myogenic cells or early differentiating muscle fibres with incomplete myofibril set. Satellite cells must be confined to the well differentiated mature muscles. Macrophages were suggested to induce young muscle fibres differentiation via releasing soluble factors during removal of cellular debris.

The discovery of carbon nanomaterials has added to the applications of carbon and created enormous interest in their development, characterization and applications in many different fields. The carbon nanotubes have unique electronic and mechanical properties. Further enhancement of the growth technique raised the nanotube yields; the single-wall [SWNTs] samples; to above 70. The prepared samples were investigated using XRD to ensure that there are nanotubes in the batch. Then, an efficient purification procedure which combines ntrifugation and precipitation has been applied. As shown in SEM micrograph that more bundles of carbon nanotubes have appeared depending on the degree of prification. The thermal behavior and stability of SWCNTs-Water has been investigated by differential scanning calorimetery [DSC]. Also, XRD of SWNT for different Y and Ni catalysts has been characterized by powder X-ray diffraction.