The annual meeting of ERCIM WG IM2IM was embedded in the workshop organized by
members (K Wolf, A Schuler) of a founding group of our ERCIM WG launching team,
FhG SCAI in St Augustin (Germany), and U Janoske from Berufakademie
(University for Cooperative Education) at Mosbach. The workshop "multiphysics
simulation in biomedical applications" was held in Mosbach at the
Berufakademie (Germany) in november 21--22, 2006.
Multiphysics simulation means usage of different solvers, thereby, coupling,
here mainly using MpCCI developed by the SCAI team.  MpCCI, hence, is the
common feature of most works presented during the workshop.

G Link (Sensor Technology, University of Erlangen) gave a talk on substitute
voice by the pharyngeal-esophageal segment (PES) and the effect of geometry on
voice quality. Simulations were based on FASTEST3D--MpCCI--CFS
(CFS: fluid/structure/acoustic home-made Galerkin least square FEM software)
Simulations have been carried out in 3D straight pipe with rectangular cross
section, including a deformable oscillating PES (variable lumen narrowing)
The computation, performed with a steady developed laminar inflow condition,
had a very high cost. Hence, 2D simulations were performed in order to test
effects of geometry changes. Velocities were measured in a physical model
(with a polyurethan PES), using particle image velocimetry.

C MŸller (CADFEM GmbH - Ansys), presented a "patient-individual dental
implant simulation", after quickly giving other simulation examples
(spine column, bone implant planning, computation of muscle forces during
body motions, gait analysis, surgery planning, such as jaw remodeling,
forced extension of palate).  FE analysis prior to intervention is aimed at
optimizing the implant position, from a single slice of the jaw region
of interest (assuming a constant jaw cross section locally, over a
15mm-thickness sample domain). The elastic modulus is estimated from the bone
density (grey level). Maximum bite forces and nutrient-dependent chewing
forces are determined.  A major goal is to avoid overloading the jaw.

JG Schmidt (NEC Research Lab., St Augustin) spoke on "integrated biomedical
informatics for the management of cerebral aneurisms".  The multi-center study
(involving many academic and industrial partners and supported by EU) is aimed
at combining data (genetics, morphodynamics,...) for rupture risk assessment.
Lattice Boltzmann method-based software (developed in Sheffield University),
includes blood clotting. The goal is to get a database of 600 aneurisms
(implicating Frangi team from Barcelona University for the 3D reconstruction).

A Burblies (FhG IFAM, Bremen) spoke on "material design for medical
applications", the main application being the orthopedic field.  The common
goals are weight reduction, structure optimization using hybride multiphase
structures.  One can use parametric optimization, topology optimization
(stress adaptation, softening material at low stress regions), taking into
account production constraints, shape optimization (changing surface to lower
stresses). Multiphase topology optimization (MPTO) is more appropriate.
Topology optimization can lead to computer-based design of open-cell foam
structures.

J Meenen (Abaqus GmbH) gave a presentation on stenting and drug delivery
from coated stents. Abaqus contains a standard implicit solver, suitable
for slow mass transfer, also used to solve fluid-structure interaction, and
an explicit dynamic solver, used when discontinuities occur (contact,...), 
especially for stent expansion and catheter retraction. Three contact
conditions are implemented: stent-catheter, catheter-blood vessel, stent-wall.
FSI is solved using Fluent/Gambit softwares coupled via MpCCI.  Drug tranfer
is differently analyzed whether convection is significant (then using a
thermal analogy) or not.

R Kršger (Ansys/Fluent) talked on "microfluidics", focusing on neutral
hydrodynamics (in opposition to electrohydrodynamics). Illustrations on
surface tension effects were given, as well as on droplet production. The
macroscopic particle model has been developed for spherical rigid particle
bigger than the mesh element size (discret particle model is then not suited). 
Vortices inside and outside a moving long rigid drop in a 2D "cylindrical"
narrow duct have been computed.

F Schonfeld (Institut fŸr Microtechnik, Mainz) talked on biomicrofluidics
(surface-tension driven liquid flows which involve new physics, rarefied gas
dynamics, ...) and development of modular chip-based lab platform. The
continuum assumption is valid for a size greater than 1microm for air and
10 nm for simple liquid (the length scale being determined by the free path
in gas (65nm for air) and by the density oscillation length in liquid
(about 10 molecular diameters)). Dielectrophoresis (DEP) of microparticles
aimed at separating cell types needs to optimize the electrode geometry using
a computer-aided design. DEP forces are balanced by Stokes viscous forces.
Magnetic manipulation of microparticles used for separation of fetal cells
from maternal blood for genetic analysis needs to shield the magnetic field
and to attach magnetic beads to cells ("magnetic fishing"). The physics
underlying electro/magneto-microfluidics has been developed.

J Berieter-Hahn (Institut fŸr Zellbiologie und Neurowissenschaft, Center of
BioMedical Engineering, Frankfurt am Main). Decubitus, aneurisms and stent
design are the main targets of research in CBME. Cell and tissue mechanics
techniques (capillary sucking, scanning acoustic (order of magnitude of 1 GHz)
microscopy, home-made dynamic viscosimetry, osmometry) are used to determine
the micromechanical features of biological tissues, stress being used to
improve tissue engineering, similarly to the ones experienced in vivo. The
main considered cell elements are membranes and cytoplasm, which interact.
Membranes are stiff in their plane but highly flexible in the normal direction
(role of the cortical cytoskeleton). Protein clusters link extracellular matrix
fibers to the cortex part of the cytoskeleton. Cytoplasm (cytosol and
cytoskeleton) is a reactive gel which behaves approximately similarly after
destruction of organelle membranes by detergents.

K Wolf (FhG SCAI) focused his talk on code coupling, using the neutral open
interface MpCCI tool. It treats FSI, aeroacoustics, magnetohydrodynamics,...
Nowadays, ten percent of users deal with biomechanics.  Among the future
developments, there are import of patient-specific data, dynamic adjustment
of CFD domain, virtual operation. Code-adapter routines between MpCCI and
solver must be written. It takes 2 to 4 weeks to be trained with simple tests
which can be validated.

M Thiriet (INRIA REO team) presented numerical results in image-based models
of physiological flows. He demonstrated how helpful computational results
can be in medical practice. He pointed also out the main drawbacks of the
methodology, leading to qualification rather than quantification.
He then talked on modelling strategies, the ancient version "reductionism"
leading to moderm "integrative approaches" of complex physiological systems.

A half-day session meeting was devoted to the 7FP, in order to define a
proposal skeleton for ICT second calls in 2007.