<font size="2" face="Arial, Helvetica, sans-serif"> </font> <p style="MARGIN-TOP: 0px; MARGIN-BOTTOM: 0px" align="justify"><font size="2" face="Arial, Helvetica, sans-serif">Confining boundaries affect the response of a medium to perturbations and its fluctuation spectrum. Consequently, they influence medium-induced and fluctuation-induced interactions between embedded particles. By considering the effect of the boundaries on the conserved fields of the medium one can distinguish between interactions that are suppressed by confinement and those which can be enhanced by it. We demonstrate in detail both suppression and enhancement of interactions for two cases: (a) the hydrodynamic interaction of particles suspended in a liquid between two rigid plates and in a linear channel; (a) the electromagnetic dispersion interaction of particles confined in a dielectric slab between two plates of another dielectric medium.</font></p> <p style="MARGIN-TOP: 0px; MARGIN-BOTTOM: 0px" align="justify"><font size="2" face="Arial, Helvetica, sans-serif"></font> </p> <p style="MARGIN-TOP: 0px; MARGIN-BOTTOM: 0px" align="justify"><font size="2"><font face="Arial, Helvetica, sans-serif"><a href="http://sciences.hit.ac.il/events/ps/fliers.2010-2011/diamant.15.feb.2011.pdf" target="_blank"> Get the flier...</a></font></font></p>