Abstract: A multi-stage puzzle that guides a user to develop support for an answer to solve and complete the puzzle that includes conducting a note taking stage, conducting an answer and support presentation stage, conducting an answer and support evaluation stage, and hindering the completion of the puzzle based on the way the user completes each stage. The note taking stage preferably includes providing a plurality of story and reference pieces that may be selected by the user. The answer and support presentation stage preferably includes retrieving an inferred answer and support for the inferred answer based on the selected story and reference pieces from the user. The answer and support evaluation stage preferably includes evaluating the inferred answer. Hindering the completion of the puzzle preferably functions to encourage the user to adequately evaluate the provide story and reference pieces and to provide adequate support for an inferred answer.

Abstract: A system for continuous perfusion culturing of anchorage-dependent and anchorage-independent mammalian cell lines, inter alia, wherein in vivo capillary bed conditions are simulated by providing a bioreactor having a growth chamber wherein the cells are grown between a multitubular array comprising at least three functionally separate, inert non-degradable and structurally strong tubes or sets of tubes. A constant nutrient gradient is maintained along the entire length of the tubes by perfusing medium through the tubes at a flow rate which is sufficient to expose all areas of the chamber to fresh medium by convective forces rather than diffusion. Oxygen transfer and removal of toxic wastes is improved by the invention herein. In a preferred embodiment, porous inert expanded Teflon tubes are employed having an inner diameter of approximately between 1 and 2 millimeters.