in this study, fe 3 o 4 superparamagnetic nanoparticles were synthesized and stabilized by chitosan. then the nanoparticles were characterized by fourier transform infrared spectroscopy and transmission electron microscopy (tem). particle size distribution and zeta potential of the particles also was assessed using malvern zetasizer. the paramagnetic behaviors of the uncoated and chitosan coate...

conclusions prognosis of this type of tumor, apart from its size and differentiation level, depends on infiltration in tumor-surrounding tissue, perineural and perivascular spread. therefore, it is always necessary to analyze the removed skin especially on margins. introduction squamous cell carcinoma is the most common type of lip and oral cavity cancers. in majority of cases it follows quite ...

Background: Activation of bone morphogenetic protein 4 (BMP4) signaling pathway in embryonic stem (ES) cells plays an important role in controlling cell proliferation, differentiation, and apoptosis. Adverse effects of BMP4 occur in a time dependent manner; however, little is known about the effect of different time exposure of this growth factor on cell number in culture media. In this study, ...

Various bacteria such as the canonical gram negative Escherichia coli or the well-studied gram positive Bacillus subtilis divide symmetrically after they approximately double their volume. Their size at division is not constant, but is typically distributed over a narrow range. Here, we propose an analytically tractable model for cell size control, and calculate the cell size and inter-division...

For many years, it has been believed that diffusion is the principle motive force for distributing molecules within the cell. Yet, our current information about the cell makes this improbable. Furthermore, the argument that limitations responsible for the relative constancy of cell size--which seldom varies by more than a factor of 2, whereas organisms can vary in mass by up to 10(24)--are base...

An adult animal consists of cells of vastly different size and activity, but the regulation of cell size remains poorly understood. Recent studies uncovering some of the signaling pathways important for size/growth control, together with the identification of diseases resulting from aberrations in these pathways, have renewed interest in this field. This Review will discuss our current understa...

Various rod-shaped bacteria such as the canonical gram negative Escherichia coli or the wellstudied gram positive Bacillus subtilis divide symmetrically after they approximately double their volume. Their size at division is not constant, but is typically distributed over a narrow range. Here, we propose an analytically tractable model for cell size control, and calculate the cell size and inte...

All organisms control the size of their cells. We focus here on the question of size regulation in bacteria, and suggest that the quantitative laws governing cell size and its dependence on growth rate may arise as byproducts of a regulatory mechanism which evolved to support multiple DNA replication forks. In particular, we show that the increase of bacterial cell size during Lenski's long-ter...