Prospectively Isolated Cancer-Associated CD10+ Fibroblasts Have Stronger Interactions with CD133+ Colon Cancer Cells than with CD133− Cancer Cells

Although CD133 has been reported to be a promising colon cancer stem cell marker, the biological functions of CD133+ colon cancer cells remain controversial. In the present study, we investigated the biological differences between CD133+ and CD133− colon cancer cells, with a particular focus on their interactions with cancer-associated fibroblasts, especially CD10+ fibroblasts. We used 19 primary colon cancer tissues, 30 primary cultures of fibroblasts derived from colon cancer tissues and 6 colon cancer cell lines. We isolated CD133+ and CD133− subpopulations from the colon cancer tissues and cultured cells. In vitro analyses revealed that the two populations showed similar biological behaviors in their proliferation and chemosensitivity. In vivo analyses revealed that CD133+ cells showed significantly greater tumor growth than CD133− cells (P = 0.007). Moreover, in cocultures with primary fibroblasts derived from colon cancer tissues, CD133+ cells exhibited significantly more invasive behaviors than CD133− cells (P<0.001), especially in cocultures with CD10+ fibroblasts (P<0.0001). Further in vivo analyses revealed that CD10+ fibroblasts enhanced the tumor growth of CD133+ cells significantly more than CD10− fibroblasts (P<0.05). These data demonstrate that the in vitro invasive properties and in vivo tumor growth of CD133+ colon cancer cells are enhanced in the presence of specific cancer-associated fibroblasts, CD10+ fibroblasts, suggesting that the interactions between these specific cell populations have important roles in cancer progression. Therefore, these specific interactions may be promising targets for new colon cancer therapies

Analytical and Experimental Study on Actuation Time of Displacement Amplified Electromagnetic Actuator

This paper describes an analytical study undertaken on an electromagnetic actuator design with a displacement amplification mechanism by explaining the physical modeling and formulizing the actuation time of the actuator in terms of physical model variables. This is followed by an experimental investigation on the actuation time of the electromagnetic actuator. Increasing the gap between the electromagnet and armatures to increase the stroke of the electromagnetic actuator resulted in a drastic loss of the thrust force. The displacement amplification mechanisms were used to increase the stroke of the actuator without incurring high levels of loss in the thrust force. For the same load and final stroke of the actuator, the actuation time was observed to model the effect of amplification ratio on the actuator. Using the physical and mathematical modeling of the displacement amplified electromagnetic actuator and by formulating the actuation time, simulations were implemented that revealed the relationship between the actuation time and amplification ratio. The design of the experimental setup and methodology of the experimentation are explained to verify the simulation results and calculated relationship between the amplification ratio and actuation time in practice. The results of simulations and experimentations showed that there is an optimum point until which the amplification ratio can be increased while advancing from actuation time for the same load and final stroke of the actuator. The similarity between the simulation and experimental results proved that the value of this optimum point could be formulized and expressed in terms of other variables used to simulate the actuator