It's a long way to multimedia: an account of 18 years of pursuing a new media project in physiology.

A teaching-oriented multimedia database authoring system, MILES ( Multimediales Informations- und Lehrsystem), has been in development since 1980 in our department. The hardware consists of a network of personal computers connected to digital and, until recently, audio/video storage devices. The system provides a database capable of handling all kinds of multimedia data and computer programs. User-friendly software provides input, editing, retrieval, and communication; the authoring system allows these components to be organized into structures of complex menus, combined with free database access. More than 12,000 components have been stored, including approximately 3,500 pictures. The paper reports on an extensive field test, in which the system has been applied as a common source for all kinds of materials used in teaching physiology to students of medicine. ResuIts show that the "new media" are powerful instruments for improving teaching and learning. However, they should not be expected to provide the sole basis for education. Their application still faces many problems regarding concepts, efficiency, and acceptance by students and staff.

[A mathematical model for the description of oxygen-diffusion in the intervillous space of the human placenta (author's transl)]. / Ein mathematisches Modell zur Beschreiburg der Sauerstoffdiffusion im intervillösen Spalt der menschlichen Placenta.

The oxygen consumption has a central place in the complicated interaction between diminished oxygen supply and degenerative trophoblastic tissue change. In the present investigation, that serves as a mathematical model, the problem of the diffusion equation for the constant state is discussed and solved. It is shown that the diminishing of length of the radius of the maternal blood compartment has the same meaning as the decrease in the flow velocity. The influence of the mass transfer coefficient h on the oxygen partial pressure and on the oxygen transfer is investigated. The influence of parameter variations on the placental alterations during toxemia is discussed and their clinical importance is obvious. Our theoretical model elusidates the value of an early therapeutical approach in the case of toxemia.

[Consideration of hemodynamics in the intervillous space of the placenta (author's transl)]. / Uberlegungen zur Haemodynamik im interfillösen Raum der Placenta.

Using Freese's hemodynamic model, we calculated the speed and pressure distribution in the villi-free area of the cotyledon. The Navier-Stokes equation was converted approximately into Reynod factors. The villi-free area was described as circular diffusor. On the basis of our computations, we assume that a predominately laminar flow occurred in the intervillous space; we considered an angular apearature of between 10 and 40 degrees to be physiological. In this area, pressure distribution is homogenous. The model-theoretical considerations presented here substantiate Freese's conception.