Subsurface cation vacancy stabilization of the magnetite (001) surface.

Iron oxides play an increasingly prominent role in heterogeneous catalysis, hydrogen production, spintronics, and drug delivery. The surface or material interface can be performance-limiting in these applications, so it is vital to determine accurate atomic-scale structures for iron oxides and understand why they form. Using a combination of quantitative low-energy electron diffraction, scanning tunneling microscopy, and density functional theory calculations, we show that an ordered array of subsurface iron vacancies and interstitials underlies the well-known (√2 × âˆš2)R45° reconstruction of Fe3O4(001). This hitherto unobserved stabilization mechanism occurs because the iron oxides prefer to redistribute cations in the lattice in response to oxidizing or reducing environments. Many other metal oxides also achieve stoichiometry variation in this way, so such surface structures are likely commonplace.

Quality control and assurance from the development to the production of biopharmaceuticals.

Consumer and patient safety have become the prerequisites for (bio)pharmaceutical product development, production and marketing. The ability to provide an effective, pure, safe product is the primary factor determining the product's success. However, with an ever-increasing number of national and international regulations, 'quality assurance' has acquired a threatening ring for many project managers. Many think that ensuring and improving quality is expensive, but regulations aid public acceptance. Good manufacturing practice can be developed into a business asset and need not be seen as merely a regulatory hurdle.

A desktop image processing system for computer-assisted orthopedic surgery (DISOS).

Within the framework of our research activities in orthopedic surgery a PC-based imageprocessing system for the processing of x-ray computer-tomographic data has been developed. The system is used as a work platform for the investigations concerning interaction modalities, strategies and techniques for an efficient planning and execution of surgical interventions in orthopedic surgery by means of individual templates. The method of individual templates has been presented in /1,2/ and will not be subject of this paper.

Performance characteristics of mammalian cell culture process operating continuously with protein-free medium.

In this communication we briefly describe a continuous industrial process for the production of Tissue Plasminogen Activator (tPA), operating with a standard, basal medium (DME/F12). Process data of two culture runs has been chosen to present a performance profile over a production period of more than 3 mo. Developmental aspects of glucose utilization (as a process parameter) are briefly discussed.

Antibody production in packed bed reactors using serum-free and protein-free medium.

The present work demonstrates the utility of packed bed reactors for the production of monoclonal antibody. We present data from a continuous process run for the production of over 100 grams of antibody, using serum-free medium. An additional pilot run also demonstrates the potential for continued antibody production under protein-free conditions, using a standard basal medium.