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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Bioprocess and biosystems engineering 6 (1991), S. 221-226 
    ISSN: 1432-0797
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Extracellular lipase production by the recombinant strain Staphylococcus carnosus (pLipMut2) has been studied. First substrate optimization was carried out in shaken cultures. As a result, the best substrate yield of 20 units/g (peptone + yeast extract) and maximum lipase activity in the culture supernatant of 1.7 units/cm3 could be obtained by a nutrient rich complex medium consisting of 75 kg/m3 yeast extract, 15 kg/m3 tryptone, 5 kg/m3 glucose and 0.5 kg/m3 K2HPO4. Higher initial substrate concentration caused inhibition of growth. Antifoam agent at higher levels than 1 cm3/ dm3 resulted in a negative influence on lipase yield. Comparative fermentation studies have been carried out in a bubble column reactor and in a centrifugal field bioreactor. Direct proportionality between growth, lipase production and oxygen consumption was observed. In the bubble column reactor usual superficial air velocities (4 cm/s) caused intensive foam generation, thus fermentation was only possible after installation of a broader column head to allow coalescence. In the centrifugal field bioreactor higher productivities were obtained without foam problems at superficial gas velocities which were one order of magnitude lower than in the bubble column. Fermentations have been performed batchwise and without holding pH constant. Neither pH control nor glucose feeding could improve the substrate yield further. Compared to former fermentation studies with the strain S. carnosus (pLipPS1) lipase yield (lipase activity/cell density) could be improved by 300% and substrate yield (lipase activity/substrate concentration) by 600%.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Journal of Chromatography B: Biomedical Sciences and Applications 584 (1992), S. 109-113 
    ISSN: 0378-4347
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Journal of Crystal Growth 102 (1990), S. 841-847 
    ISSN: 0022-0248
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Bioprocess and biosystems engineering 12 (1995), S. 87-93 
    ISSN: 1432-0797
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Baterial lipase from Staphylococcus carnosus (pLipMut2) has been immobilized on various supports in order to determine a suitable immobilization technique in terms of activity and stability, when utilized for the hydrolysis of tributyrin. The hydrophobic materials PBA Eupergit and PBA Eupergit 250L prooved to be appropriate supports, when the enzyme was crosslinked with glutaraldehyde after adsorption. No desorption of the immobilized enzyme occured during operation. The pore size of the support has a strong effect on the activity but does not influence stability. The initial activity for immobilized and soluble lipase is found to follow the Arrhenius equation at low temperature, where mass transfer does not affect reaction kinetics. Activation energies for soluble and immobilized lipase were evaluated to be 21.7 kJ mol−1 and 60.8 kJ mol−1, respectively. Operational stability was studied in a packed bed recirculation reactor. Thermal desactivation followed first order kinetics with a half-life of 1340 h at 10°C. Model calculations for productivity showed, that optimal temperatures for high productivity are well below the temperature of maximal activity.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Heat and mass transfer 18 (1984), S. 1-7 
    ISSN: 1432-1181
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Description / Table of Contents: Zusammenfassung Das Anliegen des Beitrages besteht darin zu zeigen, daß die Stoffübertragungsrate an laminar überströmten Phasengrenzflächen vor allem vom Geschwindigkeitsprofil ab-hängt. Auf die prinzipiellen Unterschiede an festen und fluiden Grenzflächen wird eingegangen.
    Notes: Abstract This article demonstrates that rates of mass transfer at interfaces in laminar flow primarily depend on the velocity profile. The generic differences between systems with fluid and solid interfaces are explained.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Der Unfallchirurg 103 (2000), S. 626-631 
    ISSN: 1433-044X
    Keywords: Schlüsselwörter Knieendoprothese ; Infektion ; Arthrodese ; Lebensqualität ; Wechseloperation ; Key words Knee arthroplasty ; Infection ; Knee arthrodesis ; Life quality ; Revision operation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract Aim of the study: In case of extensive bone loss arthrodesis can be more favourable than one or two stage revisions with new arthroplasties after infected implants. Material and methods: 19 patients with arthrodesis of the knee joint because of infected arthroplasty were clinical-radiological examined after 5.2 years. The quality of life was measured with the SF-36 score. The average age at the arthroplasty implantation was 63.8 years. 5 patients had constrained prostheses, 14 bicondylar sledge prostheses. Discussion: The average results in health orientated life quality of patients with arthrodesis in case of infected arthroplasty were lower than in control groups but singular aspects scored higher. After the arthrodesis some patients increased their levels compared to the period with arthroplasty. Clinical relevance: The fear of loss of quality after arthrodesis of the knee joint can not be supported. Some results were not better with arthroplasty or without an operation.
    Notes: Zusammenfassung Auch wenn die Zahlen von infizierten Knieendoprothesen rückläufig sind, so handelt es sich um eine ernste und folgenträchtige Komplikation. Es wurden 19 Patienten durchschnittlich 5,2 Jahre nach der Arthrodese klinisch und radiologisch nachuntersucht und mit dem SF-36-Fragebogen die Lebensqualität beurteilt. Das Durchschnittsalter bei der Primäroperation lag bei 63,8 Jahren. Die Indikation zur Primäroperation wurde in 5 Fällen aufgrund einer rheumatoiden Arthrose, je einmal wegen einer Psoriasisarthritis und einer posttraumatischen Arthrose und in 12 Fällen bei einer idiopathischen Arthrose gestellt; 5 Patienten hatten eine Scharnierprothese, 14 eine Oberflächenprothese. Es wurde in allen Fällen eine Durchbauung der Arthrodese erzielt; 7 Patienten waren komplett schmerzfrei. Mit dem SF-36-Score erreichten 10 Patienten Werte zwischen 30 und 60 und 8 zwischen 10 und 20 Punkten. Postoperativ zeigte die körperliche Funktionsfähigkeit bei 9 Patienten (50%) maximal 20, bei 2 (11%) um 80 Punkte. Nach der Arthrodese erreichten 10 Patienten (56%) zwischen 30–60 Punkten, 8 (46%) zwischen 10 und 20. Die körperliche Rollenfunktion erreichte in 61% präoperativ und in 61% nach der Arthrodese und in 78% nach der Prothese 0 Punkte; 5 Patienten (28%) erzielten nach der Arthrodese zwischen 91–100 Punkten, nach der Prothese 2 (11%). Die subjektive Gesundheitseinschätzung ergab nach den Operationen eine absteigende Tendenz. Die Vitalität hingegen stieg an. Die soziale Funktionsfähigkeit zeigte zwischen den drei Zeitperioden nur geringe Unterschiede. Mit der Zeit stiegen die Werte für die Beurteilung der Lebensqualität an, obwohl sie zur Normalbevölkerung niedriger lagen. In Einzelbereichen lagen die Ergebnisse nach der Arthrodese höher als nach der Prothese. Die Arthodese kann als Verfahren zur Sanierung einer Infektion einer Knieendoprothese empfohlen werden. Der Befürchtung eines Verlustes an Lebensqualität durch den Verlust der Beweglichkeit kann widersprochen werden.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Applied microbiology and biotechnology 39 (1993), S. 155-158 
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract A mutant strain of the deuteromycete Aureobasidium pullulans deficient in melanin synthesis was used to investigate the production of the exopolysaccharide pullulan and biomass, respectively. Shake-flask experiments with different carbon sources showed significant differences in pullulan elaboration. Sucrose was most suitable for pullulan synthesis among the carbon sources examined. Fermentations were carried out both batch-wise and continuously in a stirred vessel fermentator. In batch fermentations about 45% of the glucose offered was converted into pullulan at maximum formation rates of 0.16 g/l per hour using standard medium. The yield of polysaccharide could be maintained at 45% in continuous fermentations. At a dilution rate of 0.05 l/h, the formation rate of polysaccharide increased up to 0.35 g/l per hour. Alterations in the nitrogen content of the feed significantly affected the consumption rate of glucose and the production rate of polysaccharide, but final concentrations of biomass were hardly affected.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Bioprocess engineering 12 (1995), S. 87-93 
    ISSN: 0178-515X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract  Baterial lipase from Staphylococcus carnosus (pLipMut2) has been immobilized on various supports in order to determine a suitable immobilization technique in terms of activity and stability, when utilized for the hydrolysis of tributyrin. The hydrophobic materials PBA Eupergit and PBA Eupergit 250L prooved to be appropriate supports, when the enzyme was crosslinked with glutaraldehyde after adsorption. No desorption of the immobilized enzyme occured during operation. The pore size of the support has a strong effect on the activity but does not influence stability.The initial activity for immobilized and soluble lipase is found to follow the Arrhenius equation at low temperature, where mass transfer does not affect reaction kinetics. Activation energies for soluble and immobilized lipase were evaluated to be 21.7 kJ mol-1 and 60.8 kJ mol-1, respectively.Operational stability was studied in a packed bed recirculation reactor. Thermal desactivation followed first order kinetics with a half-life of 1340 h at 10°C. Model calculations for productivity showed, that optimal temperatures for high productivity are well below the temperature of maximal activity. List of Symbols E a [kJ mol-1] activation energy E d [kJ mol-1] activation energy of desactivation H [–] half-number k d [h-1] desactivation constant k d ,∞ [h-1] constant k N [–] desactivation constant (number) N [–] number of runs p [mol dm-3] productivity t [h] time t 0.5 [h] half-life T [K] absolute temperature V [U ml-1] activity V(N) [U ml-1] activity exhibited in the n-th run V s,0 [U ml-1] initial activity of supernatant V s,∞ [U ml-1] activity of supernatant after immobilization V 0 [U ml-1] initial activity V ∞ [U ml-1] constant η imm [–] activity yield φ [ml ml-1] ratio of volume of support to volume of supernatant
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary High resolution adsorption (HRADS) with argon and nitrogen at 77 K were performed on large crystals of zeolite ZSM-5 using a novel volumetric device. Multi-step isotherms for both adsorptives could be observed for the first time. The micropore filling was followed by low temperature microcalorimetry. Exothermic heats of adsorption were found to be correlated with steps in the adsorption isotherms. Based on results from atom-atom potential energy calculations (AAP) as well as from independent model building it is shown that 24 kinetic adsorbate molecules can be situated in a ZSM-5 unit cell. Localized adsorption is presented as possible filling mechanisms. Experimental results are reasonably interpreted assuming primary filling of narrow channels and secondary adsorption in the wider channel intersections. At least for nitrogen there is evidence for a transition of fluid-like to a solid-like adsorbate phase. Compared to argon, Henry's constants and the initial isosteric heat of adsorption indicate a stronger adsorption of nitrogen which is thought to be due to additional interactions of the nitrogen quadrupole moment with the zeolite framework.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 0009-286X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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