Producing viruses in orbit: Current developments for orbital shaken viral vaccine manufacturing

Preculture of suspension cells is successfully performed in shake flasks. Especially newly developed designer cells are passaged up to 100 times in shake flaks at high shaking frequency and are then perfectly adapted to growth in a CO2 incubator with pH control and maximum oxygen supply (typically above 80% pO2). When they are subsequently transferred to stirred tank bioreactors for scaling up, specific cell growth rates are often lower and cells become sensitive to pH control via acid/base addition and shear stress due to submers gassing (bubbles). This was also seen for avian AGE1.CR.pIX and human HEK 293 cells. To avoid these problems, scale up in shaken mode was evaluated. Here we present the latest developments of the SB10-X OSB bioreactor with regard to bag design and improvement of the control unit. A new control strategy was introduced leading to a faster and more precise pH and DO control. Furthermore, the perfusion bag was optimized, so that on TFF or two ATF systems can be easily connected. Both developments have led to a more robust SB10-X system that allows to easily perform batch, fed batch or perfusion runs. Please click Download on the upper right corner to see the full abstract

Comparison of periodontal and peri-implant probing by depth-force pattern analysis

The purpose of this study was to compare the tissue resistance to probing and the accuracy of depth determination at different force levels around implants and teeth. In 11 subjects 1 implant and 1 tooth at a comparable location and with comparable probing depth were investigated. The sites were located on either the mesial or distal aspect of the tooth and the implant. A probing device was used which allowed simultaneous monitoring of probing force and probe penetration and which standardized the insertion pathway for repeated measurements. The probing instrument was fitted with an attachment for an aiming device to take a radiograph with the probe tip in the sulcus, using a standardized projection geometry. Probing depth values were determined at 0.25, 0.50, 0.75, 1.00 and 1.25 N probing force. The standard error of the individual measurement (Si), evaluated by comparison of repeated measurements in the same session, was 0.2 mm on implants and 0.1 mm on teeth. For implants there was a trend for slightly better reproducibility at higher force levels. Curve analysis of depth force patterns showed that a change in probing force had more impact on the depth reading in the peri-implant than in the periodontal situation. The mean distance between the probe tip and the periimplant bone crest amounted to 0.75±0.60 mm at 0.25 N probing force. It is concluded that peri-implant probing depth measurements are more sensitive to force variation than periodontal pocket probing. © Munksgaard 1997.link_to_subscribed_fulltex

Search for heavy charged particles and for particles with anomalous charge in e+-e- collisions at LEP

Contains fulltext : 124552.pdf (preprint version ) (Open Access