978 resultados para Mixed-acid Fermentation
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El proyecto aborda el problema general de establecer una metodología para el cambio de escala de la producción de metabolitos en biorreactores de tanque agitado.En el desarrollo de procesos de producción de metabolitos a partir de microorganismos, el cambio de escala es particularmente complejo, dado que los microorganismos experimentan un continuo cambio en sus rutas metabólicas durante el período de producción. Esto hace que en el proceso del cambio de escala, las mayores dificultades se encuentren en el desarrollo del inóculo y problemas ocasionados por modificaciones en las características de transferencia de calor, masa y momento.Dentro de este contexto general se definen dos objetivos específicos. Estos son: el estudio de la producción de ácido itacónico por Aspergillus terreus y el de la producción de ácido hialurónico por Streptococcus equi. subsp. equi, con la finalidad de desarrollar una metodología de trabajo experimental y teórica que permita sistematizar el estudio del factibilidad técnico-económica de plantas de producción, vinculando la investigación del procesos a escala de laboratorio con la producción a mayor escala.La hipótesis de trabajo es que el estudio de la producción de Aspergillus terreus y de Streptococcus equi en un biorreactor de tanque agitado a escala de laboratorio permitirá establecer los parámetros que contribuirán a realizar el cambio de escala de su producción y esto será verificado experimentalmente.Los trabajos se realizarán utilizando un biorreactor a escala de laboratorio especialmente diseñado para este tipo de trabajo. Los resultados experimentales se interpretarán con técnicas estadísticas y matemáticas de diferente complejidad a efectos de establecer los criterios de cambio de escala y luego se realizarán experiencias en un biorreactor piloto con el objeto de verificar la metodología seleccionada.El desarrollo del proyecto permitirá:1.- obtener información técnica útil sobre la producción de ácido itacónico, el que tiene importantes aplicaciones en la industria del plástico. La producción por medio del Aspergillus terreus MJL05 se realizará utilizando glicerol como fuente de carbono, el que constituye el principal subproducto en los procesos de manufactura de biodiesel. De este modo se podrá analizar la factibilidad técnica de una ruta alternativa para emplear este subproducto.2.- obtener información técnica útil sobre la producción de ácido hialurónico, biopolímero de alto valor agregado con importantes aplicaciones en medicina, y contribuir así a realizar el cambio de escala de su producción.
The appraisal of anaerobic digestion in Ireland to develop improved designs and operational practice
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Mesophilic Anaerobic Digestion treating sewage sludge was investigated at five full-scale sewage treatment plants in Ireland. The anaerobic digestion plants are compared and evaluated in terms of design, equipment, operation, monitoring and management. All digesters are cylindrical, gas mixed and heated Continuously Stirred Tank Reactors (CSTR), varying in size from 130m3 to 800m3. Heat exchanger systems heat all digesters. Three plants reported difficulties with the heating systems ranging from blockages to insufficient insulation and design. Exchangers were modified and replaced within one year of operation at two plants. All but one plant had Combined Heat and Power (CHP) systems installed. Parameter monitoring is a problem at all plants mainly due to a lack of staff and knowledge. The plant operators consider pH and temperature the most important parameters to be measured in terms of successful monitoring of an anaerobic digester. The short time taken and the ease at which pH and temperature can be measured may favour these parameters. Three laboratory scale pilot anaerobic digesters were operated using a variety of feeds over at 144-day period. Two of the pilots were unmixed and the third was mechanically mixed. As expected the unmixed reactors removed more COD by retention of solids in the digesters but also produced greater quantities of biogas than the mixed digester, especially when low solids feed such as whey was used. The mixed digester broke down more solids due to the superior contact between the substrate and the biomass. All three reactors showed good performance results for whey and sewage solids. Scum formation occurred giving operational problems for mixed and unmixed reactors when cattle slurry was used as the main feed source. The pilot test was also used to investigate which parameters were the best indicators of process instability. These trials clearly indicated that total Volatile Fatty Acid (VFA) concentrations was the best parameter to show signs of early process imbalance, while methane composition in the biogas was good to indicate possible nutrient deficiencies in the feed and oxygen shocks. pH was found to be a good process parameter only if the wastewater being treated produced low bicarbonate alkalinities during treatment.
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Magdeburg, Univ., Fak. für Verfahrens- und Systemtechnik, Diss., 2012
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Magdeburg, Univ., Fak. für Elektrotechnik und Informationstechnik, Diss., 2012
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Magdeburg, Univ., Fak. für Mathematik, Diss., 2012
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Background: Several studies have demonstrated clinical benefits of fish consumption for the cardiovascular system. These effects are attributed to the increased amounts of polyunsaturated fatty acids in these foods. However, the concentrations of fatty acids may vary according to region. Objective: The goal of this study was to determine the amount of,cholesterol and fatty acids in 10 Brazilian fishes and in a non-native farmed salmon usually consumed in Brazil. Methods: The concentrations of cholesterol and fatty acids, especially omega-3, were determined in grilled fishes. Each fish sample was divided in 3 sub-samples (chops) and each one was extracted from the fish to minimize possible differences in muscle and fat contents. Results: The largest cholesterol amount was found in white grouper (107.6 mg/100 g of fish) and the smallest in badejo (70 mg/100 g). Omega-3 amount varied from 0.01 g/100 g in badejo to 0.900 g/100 g in weakfish. Saturated fat varied from 0.687 g/100 g in seabass to 4.530 g/100 g in filhote. The salmon had the greatest concentration of polyunsaturated fats (3.29 g/100 g) and the highest content of monounsaturated was found in pescadinha (5.98 g/100 g). Whiting and boyfriend had the best omega-6/omega 3 ratios respectively 2.22 and 1.19, however these species showed very little amounts of omega-3. Conclusion: All studied Brazilian fishes and imported salmon have low amounts of saturated fat and most of them also have low amounts of omega-3.
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experimental design, mixed model, random coefficient regression model, population pharmacokinetics, approximate design
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Magdeburg, Univ., Fak. für Mathematik, Diss., 2010
Modulation of social and emotional behaviors by glutamic acid decarboxylase (GAD) and phytoestrogens
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Magdeburg, Univ., Fak. für Naturwiss., Diss., 2014
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Mature fruits of mango 'Paheri' were treated immediately after harvest with ethefon at 0 - 250 - 500 - 1.000 and 2.000 ppm. Fruit ripening was accelerated by all treatments , the time to maturity being reduced from 48 to 72 hours, when compared with controls. Maturation was evaluated, by external colour of fruits, soluble solids and acid contents.
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We describe an equivalence of categories between the category of mixed Hodge structures and a category of vector bundles on the toric complex projective plane which verify some semistability condition. We then apply this correspondence to define an invariant which generalises the notion of R-split mixed Hodge structure and compute extensions in the category of mixed Hodge structures in terms of extensions of the corresponding vector bundles. We also give a relative version of this correspondence and apply it to define stratifications of the bases of the variations of mixed Hodge structure.
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RNA was determined in red blood cells of man and other mammals. Our report is based on 41 determinations. Red blood cells of rat showed the highest values in comparison with the blood cells of guinea pig, rabbit, horse and sheep which showed the lowest values, and man with intermediate ones. The method used was a combination of Schimidt and Thanhauser and Schneider extractions with the final reactions of pentose with the orcinol reagent colorimetrically measured.
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We study the optimal public intervention in setting minimum standards of formation for specialized medical care. The abilities the physicians obtain by means of their training allow them to improve their performance as providers of cure and earn some monopoly rents.. Our aim is to characterize the most efficient regulation in this field taking into account different regulatory frameworks. We find that the existing situation in some countries, in which the amount of specialization is controlled, and the costs of this process of specialization are publicly financed, can be supported as the best possible intervention.
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Actualment, la resposta de la majoria d’instrumentació operacional i dels dosímetres personals utilitzats en radioprotecció per a la dosimetria neutrònica és altament dependent de l’energia dels espectres neutrònics a analitzar, especialment amb camps neutrònics amb una important component intermitja. En conseqüència, la interpretació de les lectures d’aquests aparells es complicada si no es té un coneixement previ de la distribució espectral de la fluència neutrònica en els punts d’interès. El Grup de Física de les Radiacions de la Universitat Autònoma de Barcelona (GFR-UAB) ha desenvolupat en els últims anys un espectròmetre de neutrons basat en un Sistema d’Esferes Bonner (BSS) amb un contador proporcional d’3He com a detector actiu. Els principals avantatges dels espectròmetres de neutrons per BSS són: la seva resposta isotròpica, la possibilitat de discriminar la component neutrònica de la gamma en camps mixtos, i la seva alta sensibilitat neutrònica als nivells de dosi analitzats. Amb aquestes característiques, els espectròmetres neutrònics per BSS compleixen amb els estándards de les últimes recomanacions de la ICRP i poden ser utilitzats també en el camp de la dosimetria neutrònica per a la mesura de dosis en el rang d’energia que va dels tèrmics fins als 20 MeV, en nou ordres de magnitud. En el marc de la col•laboració entre el GFR - UAB i el Laboratorio Nazionale di Frascati – Istituto Nazionale di Fisica Nucleare (LNF-INFN), ha tingut lloc una experiència comparativa d’espectrometria per BSS amb els feixos quasi monoenergètics de 2.5 MeV i 14 MeV del Fast Neutron Generator de l’ENEA. En l’exercici s’ha determinat l’espectre neutrònic a diferents distàncies del blanc de l’accelerador, aprofitant el codi FRUIT recentment desenvolupat pel grup LNF. Els resultats obtinguts mostren una bona coherència entre els dos espectròmetres i les dades mesurades i simulades.