Various embodiments are described herein a membrane that may be used to affect the translocation of polymers through at least one nanopore in the membrane by incorporating an enlarged cavity within the nanopore where the cavity size is selected along with an external force strength so that a translocation time of polymers through the nanopore is affected and may result in a non-monotonic function of polymer chain length, provide a low-pass application or a bioreactor application, for example. Various combinations of such membranes may be used in polymer filtration devices.

The invention provides a medical intravenous support apparatus that facilitates patient mobility while reducing the likelihood of an accidental fall. The design incorporates improved features for bag support, tube management, cord management, patient steadiness, user-friendly braking, and electric power supply.