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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 45 (1988), S. 113-120 
    ISSN: 1432-0649
    Keywords: 78.65 ; 72.20 ; 72.40
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract There are a great variety of optical nonlinearities that can lead to the phenomenon of laser-induced gratings (LIG) in semiconductors. In the present contribution the dynamic behaviour of an induced absorber with intrinsic bistability is investigated under excitation in a LIG self-diffraction arrangement. Using CdS as a model substance, the comparison of our theoretical model with our experimental findings gives an insight into the nonlinear dynamics of the degenerate carrier system and also an estimation of the transport properties of the electron-hole plasma.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1433-044X
    Keywords: Schlüsselwörter Arthroskopische Kapsel-Labrum-Refixation ; Akute und chronische Schulterluxationen ; Isokinetik ; Key words Acute and chronic shoulder instability ; Arthrosopic suture repair ; Isokinetic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: We examined 30 patients with an arthroscopic suture repair for anterior shoulder instability in a retrospective evaluation. The follow-up period ranged from 12 to 58 months with an average of 22 months. Arthroscopic suture repairs were done on 14 patients (acute group, average age 26.1 years) with acute detached glenoid labrum, confirmed on arthro-CT, within 10 days after the injury and on 16 patients (secondary group, average age 25 years) with chronic should dislocation. The evaluation according to the Rowe scale resulted in a mean score of 97.1 for the acute group, compared with 92.7 for the secondary group. In each group we found one recurrent dislocation, which in the acute group was due to an adequate trauma. Two of the 14 acute group patients showed a reduction in external rotation of up to 20°, compared with 6 patients in the secondary group. The external rotation of one patient in the secondary group was reduced to 40°. The isokinetic muscle strength was decreased in both groups, both for 60°/s and for 120°/s, to 85% compared with the healthy side. The primary surgical therapy of young patients (below 25 years) with an acute shoulder dislocation and a detached glenoid labrum is recommended owing to the lower redislocation rate, an overall shortened course of treatment and a trend to better postsurgical range of motion.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The influence of the osmotic pressure on the viability of yeast cells was studied in batch processes. It could be found, that the viability is a function of the total osmotic pressure obtained by adding the partial osmotic values of the principal ingredients saccharose, ethanol and salts dissolved in the medium. At optimum process conditions (pH, T, etc.) the cells can tolerate the osmotic pressure up to fixed value π1. Above π1 the viability decreases linearly and upward of a second threshold value π2 nonlinearly. In the case of the used strain Saccharomyces cerevisiae Hansen Sc 5 the values of the both points are π1 = 25 atm and π2 = 47 atm.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The influence of sucrose concentration on the specific ethanol production rate was studied during batch processes using the yeast strain Saccharomyces cerevisiae Hansen Sc 5. From experimental data a model could be derived for the simulataneous effect of substrate and product inhibition. It was found that both the decreases of fermentation activity of the cells caused by sucrose and ethanol have an additional relation to each other. This model also takes into consideration the fact that the maximum ethanol concentration P′ can't be realized at high substrate concentrations in a batch process. Compared to it sucrose concentrations below 100 g/l did not inhibit the ethanol production by the strain used in this investigation.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The ethanol-inhibitory behaviour of the yeast Saccharomyces cerevisiae Sc 5 was found to be characterized by a continual-linear relation between the specific ethanol formation rate and the ethanol concentration. Therefore the simple equation \documentclass{article}\pagestyle{empty}\begin{document}$$v = v_0 - a \cdot P$$\end{document} could be applied for it.It is shown that this model is correct only then, if all of the process parameters are in their optimum.Out of the optimum temperature range the characteristics of the function ν = f(P) change in such a way that in regard to the ethanol concentration P twc linear relations exist for each suboptimum temperature: \documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c} {v_T = v'_{0T} - a_0 \cdot e^{nT} \cdot P,} & {{\rm for}} & {P 〈 P_T } & {{\rm and}} \\\end{array} $$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c} {v_T = v_0 - a \cdot P,} & {{\rm for}} & {P 〉 P_T ,} \\\end{array} $$\end{document} and a non-linear equation is current for each superoptimum temperature: \documentclass{article}\pagestyle{empty}\begin{document}$$ v_T = v'_{0T} - a_0 ^\prime \cdot e^{mT} \cdot P^{b_T } , $$\end{document} where bT is also a function of the temperature and always less than 1.Taking as a basis these equations the specific ethanol formation rate of the used strain can be calculated for the whole biokinetic P/T-sphere of ethanol production.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: In growth-factor limited fermentations carried out in continuous high-flow rate fermenters the relationship existing between the specific ethanol formation rate and the ethanol concentration was found to change its characteristics from a linear function into a nonlinear one at high biomass concentrations. The deviation from the linear inhibitory behaviour of the cells was the greater the more the biomass concentration increased.A very good correspondence between the experimentally found productivities of ethanol formation and its adequate values obtained by calculation could be attained by using an improved steady-state productivity model, in which the variability of the function v = f(P) had been considered.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 9 (1989), S. 123-129 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The continuous ethanol production by free and Ca-alginate-entrapped cells of the yeast Saccharomyces cer. IBT H 191 was investigated in a membrane reactor and in a CSTR, respectively. An empiric productivity model for free-cell fermentation was found to be valid for immobilized cells if no external diffusion resistance existed within the reactor. In such a case the fermentative power of the immobilized cells was identical with this one of the free cells. A change of the ethanol-tolerance behaviour of the cells as a result of the cell-immobilization did not occur.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Potato starch hydrolysis products were analyzed for glucose, maltose, higher oligomeric carbohydrates (to a degree of polymerization, dp 11) and 5-hydroxymethylfurfural (HMF) using high-performance liquid chromatography.For quick qualitative and quantitative analyses short glass columns [12] of high efficiency were useful.The hydrolyses were carried out by means of enzymes (e.g. α- and β-amylase) or mineral acids. For the acid degradation procedures hydrochloric acid, sulfuric acid and phosphoric acid of different concentrations (0.1…2.0 N) during times ranging from 5 to 60 min at temperatures ranging from 100 to 140°C were used.Maximum glucose contents (163.4 g/l and 169.3 g/l) were found after 40 to 50 min of hydrolysis in 0.1 N hydrochloric acid heated to 120°C. These values are equivalent to 78.9% or 81.7% glucose yield referred to the initial potato starch amount, respectively. The calculated HMF concentrations were 140 and 180 mg/l.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 6 (1986), S. 55-62 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The production costs of ethanol are dependent on the efficiency of the substrate-ethanol conversion to a high degree. The more the substrate used during the fermentation is converted into alcohol the better is the economy of the process.Therefore the ethanol yield Y SP is an important object of the process optimization.In batch fermentation processes the most essential influence factors are the initial biomass concentration X0, the initial substrate concentration S0, the temperature T, and the pH-value.A model reflecting the complex relationships between these influence factors and the ethanol yield could be obtained by regression. It allows an exact valuation of these optimum process parameters which are necessary for realizing high ethanol yields in the batch fermentation.For the strain Saccharomyces cerevisiae Sc 5 used in this research was found an ethanol yield maximum YSP = 0·5384 at the parameters X0 = 64.61 g/l S0 = 82.91 g/l T = 36.45°C pH = 6.54.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 7 (1987), S. 237-245 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: In commercial batch processes the productivity of product formation is low. But a significant increase of productivity can be achieved in continuous fermentations. By using high flow rate fermenter systems characterized by a relatively long retention time of biomass in comparison with the retention time of the liquid we can realize a high-performance fermentation. The problem of holding back the biomass within the reactor could be solved by means of membranes being impenetrable to the cells, but permeable to the hydraulic phase. Such a process technology was successfully tested for its applicability in alcoholic and lactic acid fermentations. The maximum productivities obtained on this way were ṗ = 120 g/l. · h for ethanol production and ṗ = 51 g/l. h for lactic acid fermentation, respectively.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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