Asymmetric Shrink Fit of a Cylindrical Shell

Lymphocytes shrink to stay fit

In response to an infection, proinfl ammatory cytokines stimulate lymphocytes to take up nutrients so that they can proliferate and mount an immune response. Once the infection is cleared, however, cytokine levels decline and the lymphocytes’ nutrient supply is abruptly cut off. Most of the cells quickly die by apoptosis, but a small fraction survive and differentiate into longlived memory cell...

How chromosomes shrink to fit

Cells in an early embryo need to downsize their DNA. Ladouceur et al. show that a cell’s size and the size of its nucleus determine how small its chromosomes become (1). Like someone who’s moved from a house to an apartment, cells in an early embryo run into space limitations. The embryo remains the same size for its fi rst few divisions, so the cells have to become much smaller, shrinking by a...

Modeling of Vibration of a Fluidized Bed Cylindrical Shell

A charged rotating cylindrical shell

We give an example of a spacetime having an infinite thin rotating cylindrical shell constituted by a charged perfect fluid as a source. Then we disscuss the energy conditions and we show that our spacetime contains closed timelike curves. Trajectories of charged test particles both inside and outside the cylinder are also examined. Expression for the angular velocity of a circular motion insid...

Optimal Thickness of a Cylindrical Shell

In this paper an optimization problem for a cylindrical shell is discussed. The aim is to look for an optimal thickness of a shell to minimize the deformation under an applied external force. As a side condition, the volume of the shell has to stay constant during the optimization process. The deflection is calculated using an approach from shell theory. The resulting control-to-state operator ...