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711.
Ohne Zusammenfassung  相似文献   
712.
The production of recombinant therapeutic proteins from animal or human cell lines entails the risk of endogenous viral contamination from cell substrates and adventitious agents from raw materials and environment. One of the approaches to control such potential viral contamination is to ensure the manufacturing process can adequately clear the potential viral contaminants. Viral clearance for production of human monoclonal antibodies is achieved by dedicated unit operations, such as low pH inactivation, viral filtration, and chromatographic separation. The process development of each viral clearance step for a new antibody production requires significant effort and resources invested in wet laboratory experiments for process characterization studies. Machine learning methods have the potential to help streamline the development and optimization of viral clearance unit operations for new therapeutic antibodies. The current work focuses on evaluating the usefulness of machine learning methods for process understanding and predictive modeling for viral clearance via a case study on low pH viral inactivation.  相似文献   
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B Helpap  V Grouls  U Hesse 《Cryobiology》1985,22(2):168-174
Focal thermo- and cryolesions were placed on one kidney and the liver of Wistar rats. The wound healing was investigated histologically and by tritiated thymidine autoradiography. Furthermore, the 3H labeling indices of neutrophilic and eosinophilic promyelocytes and myelocytes as well as that of erythroblasts were determined in bone marrow samples from femur and vertebra. Normal nonoperated rats and rats which underwent sham operation (simple laparotomy) served as controls. The cryonecrosis healed completely after 4 weeks, whereas thermonecrotic areas were still observed 12 weeks after operation. The maximum mesenchymal and epithelial proliferation occurred between the 2nd and 3rd postoperative days. In the bone marrow, the highest labeling indices were estimated in animals with thermonecrosis, with values remaining increased during the 2 weeks after operation. Significant differences between the bone marrow response after cryolesions and sham operation were not observed. Thermolesions of internal organs, for example, after electrocoagulation, evoke a persisting local granulomatous inflammation accompanied by a distinct bone marrow reaction probably because of the pure resorption of carbonized tissue components. Iatrogenic cryolesions, in contrast, are characterized by a quick and uncomplicated wound healing without a significantly increased proliferation of bone marrow cells, thus corresponding to the wound healing after sham operation.  相似文献   
716.
Pollen grain polarity, aperture condition and pollen tube formation were examined inEphedra americana, E. foliata, E. rupestris, E. distachya, andE. fragilis using LM, SEM and TEM. In the characteristic oblate pollen, as seen in situ in the tetrad configuration, the polar axis is the minor one and the equatorial plane runs between the two narrow ends of the microspore. The intine is thick in fresh fixed mature pollen but we have seen no indication of regions having an exceptionally thick intine that could be considered associated with an aperture or apertures. About three minutes after transferring fresh pollen to the germinating medium the ridged exine splits and twists away from the intine and its enclosed protoplast. The shed exine spreads out and curls into a scroll-like configuration that is as distinctive as that of the pollen shape had been but now having the ridges and valleys perpendicular to the long axis. The pollen tube develops, in our experience with more than a hundred germinating pollen grains, near one of the narrow tips of the pollen grain's equatorial plane. The location of the pollen tube initiation probably is related to the position of the tube cell nucleus. The pollen tube starts to grow about one hour after the exine was shed. The pollen tube emerges close to the narrow end (equator) of the gametophyte. This end emerged first as the exine is shed and is opposite to the prothallial cells. The stout pollen tube is c. 10µm in diameter grown in vitro on agar. In our germination medium the stout tube continued to elongate for about 24 hours reaching a length of c. 100 µm. With respect to exine morphology the aperture condition could be considered as inaperturate. The pollen tube, however, is formed in a germination area near one end of the exineless gametophyte.  相似文献   
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