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  Cancer stem cells (CSC) are the tumor-associated cells existed within tumors or hematological cancers which share characteristics similar to normal stem cells. The common characteristics of a normal stem cell and a CSC are their differentiation capacity and self-renewal in tumors. The expression pattern of CSC markers differs depending on the type and location of cancers. CD molecules are probably the most common biomarkers for CSCs. CD molecules such as CD133, CD24, CD44, CD138 and similar CD molecules are well known markers for identification of CSCs. In addition, ATP-Binding Cassette (ABC) transporters such as ABCG2 and ABCB5 as well as EpCAM, ALDH1 and CXCR4 have been used to identify certain CSCs. Therefore these markers may be considered specific for better identification and diagnosis of a specific tumor. Currently studies are in progress to find new cell surface markers which can distinguish specific markers from other markers for isolation and characterization of CSCs. The future of this area of research is promising in developing novel prognostic assays and therapeutic approaches based on cellular and signaling functions of these markers.

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The main objective of utilizing nozzles is to convert the chemical energy to kinetic energy producing thrust. Wide variety of parameters make significant impact on nozzle performance; one of which produces significant effect is back pressure or ambient pressure. Basically, a nozzle designed for a specific back pressure does not work properly when the engine is ascending. Consequently, designing of nozzles needs knowledge of full effect of back pressure on engine performance. In this study, numerical simulation of three solid propellant nozzles have been conducted in several flight conditions. In other words, simulations have done in some ambient pressures which represents specific flight altitudes. Numerical modeling has been conducted aiding commercial code FLUENT. k-ϵ RNG turbulence model has been used for calculating turbulence interactions with the flow. Mass flow rate, chemical species, and chamber temperature have been used as the inlet boundary conditions based on engine specifications. Numerical results show a reasonable accuracy in comparison with experimental measurements. Estimating nozzle thrust level as a function of altitude increment is the primary goal of this study. Furthermore, with the aid of this relation and a MATLAB code for computing average specific impulse, optimum expansion ratio can be achieved based on a specified mission.