Sharif Digital Repository

Membrane nanotubes, ubiquitous in cellular systems, adopt a spectrum of curvatures and shapes that are dictated by their intrinsic physical characteristics as well as their interactions with the local cellular environment. A high bending flexibility is needed in the crowded cytoplasm where tubes often need to bend significantly in the axial direction at sub-micron length scales. We find the stiffness of spontaneously formed membrane nanotubes by measuring the persistence length of reconstituted membrane nanotubes freely suspended in solution and imaged by fluorescence microscopy. By quantifying the tube diameter we demonstrate for the first time that the persistence length scales linearly... 

Contamination of pistachio nuts with aflatoxin is one of the most significant issues related to pistachio health and expert. A fast pistachio aflatoxin concentration measurement method based on the laser induced fluorescence spectroscopy (LIFS) is proposed. The proposed method from theoretical and experimental points of view is analyzed. In our experiments XeCl Excimer laser is employed as an Ultra Violet (UV) source (λ=308 nm) and a UV-visible (UV-vis) spectrometer is used for fluorescent emission detection. Our setup is employed to measure the concentration of different type of Aflatoxins in pistachio nuts. Measurements results obtained by the LIFS method are compared with those are... 

Engineered nanoparticles are increasingly being considered for use as biosensors, imaging agents and drug delivery vehicles. Their versatility in design and applications make them an attractive proposition for new biological and biomedical approaches. Despite the remarkable speed of development in nanoscience, relatively little is known about the interaction of nanoscale objects with living systems. In a biological fluid, proteins associate with nanoparticles, and the amount and the presentation of the proteins on their surface could lead to a different in vivo response than an uncoated particle. Here, in addition to protein adsorption, we are going to introduce concept of cell "vision",... 

Retinal pigment epithelial (RPE) cells are indispensable for eye organogenesis and vision. To realize the therapeutic potential of in vitro-generated RPE cells for cell-replacement therapy of RPE-related retinopathies, molecular mechanisms of RPE specification and maturation need to be investigated. So far, many attempts have been made to decipher the regulatory networks involved in the differentiation of human pluripotent stem cells into RPE cells. Here, we exploited a highly-efficient RPE differentiation protocol to determine global expression patterns of microRNAs (miRNAs) during human embryonic stem cell (hESC) differentiation into RPE using small RNA sequencing. Our results revealed a...