The appearance of high resolution neutral lipid signals in the 1H NMR spectra of myeloma cells grown in the presence of oleate was shown to correlate with the appearance of cytoplasmic lipid droplets observable by electron microscopy. The spin-spin relaxation times of these lipid signals were similar to those measured previously for lipid resonances in other cell types. These data suggest that cytoplasmic lipid droplets could make a significant contribution to the neutral lipid signals observed in the 1H NMR spectra of some cells.

We have used diffusion-weighted 1H NMR micro-imaging and localized spectroscopy techniques to monitor the growth and distribution of mammalian cells in a hollow-fiber bioreactor. Non-invasive NMR measurements of this type should also allow investigation of metabolic heterogeneity and assist in future designs of hollow-fiber systems.

The present paper is a survey and research paper on the treatment of optimal control problems of rigid-link manipulators by indirect methods. Maximum Principle based approaches provide an excellent tool to calculate optimal reference trajectories for multi-link manipulators with high accuracy. Their major drawback was the need to explicitly formulate the complicated system of adjoint differential equations and to apply the full apparatus of optimal control theory. This is necessary in order to convert the optimal control problem into a piecewise defined, nonlinear multi-point boundary value problem. An accurate and efficient access to first-and higher-order derivatives is crucial. The approach described in this paper allows it to generate all the derivative information recursively and simultaneously with the recursive formulation of the equations of motion. Nonlinear state and control constraints are treated without any simplifications by transforming them into sequences of systems of linear equations. By these means, the modeling of the complete optimal control problem and the accompanying boundary value problem is automated to a great extent. The fast numerical solution is by the advanced multiple shooting method JANUS.

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