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41.
Edson Romano Nucci Antonio J. G. Cruz Roberto C. Giordano 《Bioprocess and biosystems engineering》2010,33(5):557-564
The complexity of biological processes often makes impractical the development of detailed, structured phenomenological models
of the cultivation of microorganisms in bioreactors. In this context, data pre-treatment techniques are useful for bioprocess
control and fault detection. Among them, principal component analysis (PCA) plays an important role. This work presents a
case study of the application of this technique during real experiments, where the enzyme penicillin G acylase (PGA) was produced
by Bacillus megaterium ATCC 14945. PGA hydrolyzes penicillin G to yield 6-aminopenicilanic acid (6-APA) and phenyl acetic acid. 6-APA is used to
produce semi-synthetic β-lactam antibiotics. A static PCA algorithm was implemented for on-line detection of deviations from
the desired process behavior. The experiments were carried out in a 2-L bioreactor. Hotteling’s T
2 was the discrimination criterion employed in this multivariable problem and the method showed a high sensibility for fault
detection in all real cases that were studied. 相似文献
42.
Lisa M. Landino Carolyn M. Brown Carolyn A. Edson Laura J. Gilbert Nathan Grega-Larson Anna Jean Wirth Kelly C. Lane 《Analytical biochemistry》2010,402(1):102-270
Numerous studies of S-glutathionylation of cysteine thiols indicate that this protein modification plays a key role in redox regulation of proteins. To facilitate the study of protein S-glutathionylation, we developed a synthesis and purification to produce milligram quantities of fluorescein-labeled glutathione. The amino terminus of the glutathione tripeptide reacted with fluorescein isothiocyanate readily in ammonium bicarbonate. Purification by solid phase extraction on C8 and C18 columns separated excess reactants from desired products. Both oxidized and reduced fluorescein-labeled glutathione reacted with a variety of thiol-containing proteins to yield fluorescent proteins. 相似文献
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Tramadol (T) is available as a racemic mixture of (+)‐trans‐T and (−)‐trans‐T. The main metabolic pathways are O‐demethylation and N‐demethylation, producing trans‐O‐desmethyltramadol ( M1 ) and trans‐N‐desmethyltramadol ( M2 ) enantiomers, respectively. The analgesic effect of T is related to the opioid activity of (+)‐trans‐T and (+)‐ M1 and to the monoaminergic action of (+/−)‐trans‐T. This is the first study using tandem mass spectrometry as a detection system for the simultaneous analysis of trans‐T, M1 , and M2 enantiomers. The analytes were resolved on a Chiralpak® AD column using hexane:ethanol (95.5:4.5, v/v) plus 0.1% diethylamine as the mobile phase. The quantitation limits were 0.5 ng/ml for trans‐T and M1 and 0.1 ng/ml for M2 . The method developed and validated here was applied to a pharmacokinetic study in rats. Male Wistar rats (n = 6 at each time point) received a single oral dose of 20 mg/kg racemic trans‐T. Blood samples were collected up to 12 h after drug administration. The kinetic disposition of trans‐T and M2 was enantioselective (AUC(+)/(−) ratio = 4.16 and 6.36, respectively). The direction and extent of enantioselectivity in the pharmacokinetics of trans‐T and M2 in rats were comparable to data previously reported for healthy volunteers, suggesting that rats are a suitable model for enantioselective studies of trans‐T pharmacokinetics. Chirality, 2011. © 2010 Wiley‐Liss, Inc. 相似文献
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