Plants produce a variety of secondary metabolites, e.g. to defend themselves against herbivores or to attract pollinating insects. Plant cell biotechnology offers excellent opportunities in order to use such secondary plant metabolites to produce goods with consistent quality and quantity throughout the year, and therefore to act independently from biotic and abiotic environmental factors. This article presents results of an extensive study of plant cell in vitro cultivation in a modern shake flask system with non-invasive online respiration activity monitoring unit. Comprehensive screening experiments confirm the successful transfer of a model culture (sunflower suspension) into the shake flask monitoring device and the suitability of this respiration activity monitoring unit as qualified tool for screening of plant in vitro cultures (sunflower and sage suspension). The authors demonstrate deviations between online and offline data due to varying water evaporation from different culture flask types. The influence of evaporation on growth-specific parameters thereby rises with increasing cultivation time. Furthermore, possibilities to minimize the impact of evaporation, either by adjusting the inlet air moisture or by measuring the evaporation in combination with an appropriate correction of the measured growth values, are shown.

Plants produce a variety of secondary metabolites, e.g. to defend themselves against herbivores or to attract pollinating insects. Plant cell biotechnology offers excellent opportunities in order to use such secondary plant metabolites to produce goods with consistent quality and quantity throughout the year, and therefore to act independently from biotic and abiotic environmental factors. This article presents results of an extensive study of plant cell in vitro cultivation in a modern shake flask system with non-invasive online respiration activity monitoring unit. Comprehensive screening experiments confirm the successful transfer of a model culture (sunflower suspension) into the shake flask monitoring device and the suitability of this respiration activity monitoring unit as qualified tool for screening of plant in vitro cultures (sunflower and sage suspension). The authors demonstrate deviations between online and offline data due to varying water evaporation from different culture flask types. The influence of evaporation on growth-specific parameters thereby rises with increasing cultivation time. Furthermore, possibilities to minimize the impact of evaporation, either by adjusting the inlet air moisture or by measuring the evaporation in combination with an appropriate correction of the measured growth values, are shown.

Optimising illumination is essential for optimising the growth of phototrophic cells and their production of desired metabolites and/or biomass. This requires appropriate modulation of light and other key inputs and continuous online monitoring of their metabolic activities. Powerful non-invasive systems for cultivating heterotrophic organisms include shake flasks in online monitoring units, but they are rarely used for phototrophs because they lack the appropriate illumination design and necessary illuminatory power. This study presents the design and characterisation of a photosynthetic shake flask unit, illuminated from below by warm white light-emitting diodes with variable light intensities up to 2300 μmol m-2 s-1. The photosynthetic unit was successfully used, in combination with online monitoring of oxygen production, to cultivate Arthrospira platensis. In phototrophic growth under continuous light and a 16 h light/8 h dark cycle (light intensity: 180 μmol m-2 s-1), the oxygen transfer rate and biomass-related oxygen production were - 1.5 mmol L-1 h-1 and 0.18 mmol O2 gx-1 h-1, respectively. The maximum specific growth rate was 0.058 h-1, during the exponential growth phase, after which the biomass concentration reached 0.75 g L-1.

No description available.

The goal of a Brain-Computer Interface (BCI) consists of the development of a unidirectional interface between a human and a computer to allow control of a device only via brain signals. While the BCI systems of almost all other groups require the user to be trained over several weeks or even months, the group of Prof. Dr. Klaus-Robert Müller in Berlin and Potsdam, which I belong to, was one of the first research groups in this field which used machine learning techniques on a large scale. The adaptivity of the processing system to the individual brain patterns of the subject confers huge advantages for the user. Thus BCI research is considered a hot topic in machine learning and computer science. It requires interdisciplinary cooperation between disparate fields such as neuroscience, since only by combining machine learning and signal processing techniques based on neurophysiological knowledge will the largest progress be made.<br><br> In this work I particularly deal with my part of this project, which lies mainly in the area of computer science. I have considered the following three main points:<br><br> <b>Establishing a performance measure based on information theory:</b> I have critically illuminated the assumptions of Shannon's information transfer rate for application in a BCI context. By establishing suitable coding strategies I was able to show that this theoretical measure approximates quite well to what is practically achieveable.<br> <b>Transfer and development of suitable signal processing and machine learning techniques:</b> One substantial component of my work was to develop several machine learning and signal processing algorithms to improve the efficiency of a BCI. Based on the neurophysiological knowledge that several independent EEG features can be observed for some mental states, I have developed a method for combining different and maybe independent features which improved performance. In some cases the performance of the combination algorithm outperforms the best single performance by more than 50 %. Furthermore, I have theoretically and practically addressed via the development of suitable algorithms the question of the optimal number of classes which should be used for a BCI. It transpired that with BCI performances reported so far, three or four different mental states are optimal. For another extension I have combined ideas from signal processing with those of machine learning since a high gain can be achieved if the temporal filtering, i.e., the choice of frequency bands, is automatically adapted to each subject individually.<br> <b>Implementation of the Berlin brain computer interface and realization of suitable experiments:</b> Finally a further substantial component of my work was to realize an online BCI system which includes the developed methods, but is also flexible enough to allow the simple realization of new algorithms and ideas. So far, bitrates of up to 40 bits per minute have been achieved with this system by absolutely untrained users which, compared to results of other groups, is highly successful. / Ein Brain-Computer Interface (BCI) ist eine unidirektionale Schnittstelle zwischen Mensch und Computer, bei der ein Mensch in der Lage ist, ein Gerät einzig und allein Kraft seiner Gehirnsignale zu steuern. In den BCI Systemen fast aller Forschergruppen wird der Mensch in Experimenten über Wochen oder sogar Monaten trainiert, geeignete Signale zu produzieren, die vordefinierten allgemeinen Gehirnmustern entsprechen. Die BCI Gruppe in Berlin und Potsdam, der ich angehöre, war in diesem Feld eine der ersten, die erkannt hat, dass eine Anpassung des Verarbeitungssystems an den Menschen mit Hilfe der Techniken des Maschinellen Lernens große Vorteile mit sich bringt. In unserer Gruppe und mittlerweile auch in vielen anderen Gruppen wird BCI somit als aktuelles Forschungsthema im Maschinellen Lernen und folglich in der Informatik mit interdisziplinärer Natur in Neurowissenschaften und anderen Feldern verstanden, da durch die geeignete Kombination von Techniken des Maschinellen Lernens und der Signalverarbeitung basierend auf neurophysiologischem Wissen der größte Erfolg erzielt werden konnte.<br><br> In dieser Arbeit gehe ich auf meinem Anteil an diesem Projekt ein, der vor allem im Informatikbereich der BCI Forschung liegt. Im Detail beschäftige ich mich mit den folgenden drei Punkten:<br><br> <b>Diskussion eines informationstheoretischen Maßes für die Güte eines BCI's:</b> Ich habe kritisch die Annahmen von Shannon's Informationsübertragungsrate für die Anwendung im BCI Kontext beleuchtet. Durch Ermittlung von geeigneten Kodierungsstrategien konnte ich zeigen, dass dieses theoretische Maß den praktisch erreichbaren Wert ziemlich gut annähert.<br> <b>Transfer und Entwicklung von geeigneten Techniken aus dem Bereich der Signalverarbeitung und des Maschinellen Lernens:</b> Eine substantielle Komponente meiner Arbeit war die Entwicklung von Techniken des Machinellen Lernens und der Signalverarbeitung, um die Effizienz eines BCI's zu erhöhen. Basierend auf dem neurophysiologischem Wissen, dass verschiedene unabhängige Merkmale in Gehirnsignalen für verschiedene mentale Zustände beobachtbar sind, habe ich eine Methode zur Kombination von verschiedenen und unter Umständen unabhängigen Merkmalen entwickelt, die sehr erfolgreich die Fähigkeiten eines BCI's verbessert. Besonders in einigen Fällen übertraf die Leistung des entwickelten Kombinationsalgorithmus die beste Leistung auf den einzelnen Merkmalen mit mehr als 50 %. Weiterhin habe ich theoretisch und praktisch durch Einführung geeigneter Algorithmen die Frage untersucht, wie viele Klassen man für ein BCI nutzen kann und sollte. Auch hier wurde ein relevantes Resultat erzielt, nämlich dass für BCI Güten, die bis heute berichtet sind, die Benutzung von 3 oder 4 verschiedenen mentalen Zuständen in der Regel optimal im Sinne von erreichbarer Leistung sind. Für eine andere Erweiterung wurden Ideen aus der Signalverarbeitung mit denen des Maschinellen Lernens kombiniert, da ein hoher Erfolg erzielt werden kann, wenn der temporale Filter, d.h. die Wahl des benutzten Frequenzbandes, automatisch und individuell für jeden Menschen angepasst wird.<br> <b>Implementation des Berlin Brain-Computer Interfaces und Realisierung von geeigneten Experimenten:</b> Eine weitere wichtige Komponente meiner Arbeit war eine Realisierung eines online BCI Systems, welches die entwickelten Methoden umfasst, aber auch so flexibel ist, dass neue Algorithmen und Ideen einfach zu verwirklichen sind. Bis jetzt wurden mit diesem System Bitraten von bis zu 40 Bits pro Minute von absolut untrainierten Personen in ihren ersten BCI Experimenten erzielt. Dieses Resultat übertrifft die bisher berichteten Ergebnisse aller anderer BCI Gruppen deutlich. <br> <hr> Bemerkung:<br> Der Autor wurde mit dem <i>Michelson-Preis</i> 2005/2006 für die beste Promotion des Jahrgangs der Mathematisch-Naturwissenschaftlichen Fakultät der Universität Potsdam ausgezeichnet.

Submitted by TIAGO AZEVEDO BENITES null (tiagoazb@gmail.com) on 2017-10-09T17:59:58Z No. of bitstreams: 1 Tese Tiago.pdf: 5384805 bytes, checksum: 86cf0d44920d96e8154badd25a07c674 (MD5) / Approved for entry into archive by Monique Sasaki (sayumi_sasaki@hotmail.com) on 2017-10-09T19:38:54Z (GMT) No. of bitstreams: 1 benites_ta_dr_araiq.pdf: 5384805 bytes, checksum: 86cf0d44920d96e8154badd25a07c674 (MD5) / Made available in DSpace on 2017-10-09T19:38:54Z (GMT). No. of bitstreams: 1 benites_ta_dr_araiq.pdf: 5384805 bytes, checksum: 86cf0d44920d96e8154badd25a07c674 (MD5) Previous issue date: 2017-09-01 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Dentro da eletroquímica, o estudo de reações de transferência de elétrons (TE) pode ser explorado por meio de eletrodos de ouro modificados com monocamadas auto-organizadas (SAMs), visto que elas são capazes de modificar as propriedades físico-químicas superficiais e controlar a cinética de TE. Este trabalho investigou as reações de TE em eletrodos de ouro modificados com SAMs eletroativas. Especificamente, foi estudado a cinética de TE em SAMs de 11-ferrocenil-undecanotiol sobre superfícies de ouro, por meio de análise de voltametria cíclica e espectroscopia de impedância/capacitância eletroquímica (EIE/ECE). Por meio dessas técnicas foi possível estimar variáveis como a densidade de estados redox (aproximadamente 3,4×〖10〗^14 estados cm-2 próximos aos valores reportados na literatura), de capacitância eletroquímica ou redox (137(±9) μF 〖cm〗^(-2)), a constante cinética de transferência de elétrons em 1,05×〖10〗^4 s^(-1) similares às reportadas por Creager, além da estimativa da energia de reorganização de Marcus (λ) em torno de 1,0 eV, valores similares a outros já previamente estimados para funcionalizações de SAMs eletroativas. Expandiram-se essas análises por meio da imobilização de complexos eletroativos de Bis(2,2′-bipiridina)-(5-Aminofenantrolina)rutênio bis(hexafluorofosfato) sobre superfícies de Au, por síntese orgânica com tióis ancoradores de diferentes cadeias (cisteína e 3-ácido carboxílico-6-mercaptopiridina), utilizando reação de ativação com DIC/HOBt em acetonitrila. Neste caso, obteve-se uma densidade de estados redox de cerca de 8,9×〖10〗^14 estados cm-2 e 9,3×〖10〗^14 estados cm-2, além de uma constante cinética de 2,6×〖10〗^3 s^(-1) e 1,07×〖10〗^3 s^(-1) para as abordagens I (3-ácido carboxílico-6-mercaptopiridina) e II (Cisteína) respectivamente. Resultados sugeriram uma maior capacidade das moléculas ancoradoras compostas de anel piridinico (abordagem I) na condução de carga quando comparados com a abordagem II, o que foi posteriormente confirmado por análise de condutância em que a abordagem I apresentou G=6×〖10〗^(-3) S contra G=2×〖10〗^(-3) S da abordagem II. Este trabalho apresentou uma abordagem teórico-experimental que relaciona as componentes físico-químicas quânticas através de uma nova perspectiva baseada nos estudos teóricos de Marcus-Buttiker e em análises experimentais centradas na capacitância eletroquímica. / In electrochemistry, the study of electron transfer reactions (TE) can be explored using Au electrodes modified with self-assembled monolayers (SAMs), since they are able to modify the physicochemical properties of electrodes surface and control the TE kinetics. This work investigated TE reactions on Au electrodes modified with SAMs. Specifically, TE kinetics were studied using 11-ferrocenyl-undecanethiol SAMs on Au surfaces by means of cyclic voltammetry and electrochemical impedance/capacitance spectroscopy (EIS/ECS) analysis. By means of these techniques, it was possible to estimate variables such as the density of redox states (approximately 3.4 × 1014 states per cm-2 , near the reported results in the literature), electrochemical or redox capacitance (137(±9) �� ��−2 ), the kinetic electron transfer constant at 1.05 × 104 � −1 similar to those reported by Creager, in addition to the estimation of the Marcus´ reorganization energy (�) of around 1.0 eV, value similar to others already previously estimated for functionalization of electroactive SAMs. These analyzes were expanded by immobilization of Bis(2,2'-bipyridine)-(5-Aminophenanthroline)ruthenium-bis (hexafluorophosphate) electroactive complexes on Au surfaces by organic synthesis with anionic thiols of different chains (cysteine and 3-carboxylic acid-6-mercaptopyridine), using activation reaction with DIC/HOBt in acetonitrile. In this case, a redox state density of about 8.9 × 1014 states cm-2 and 9.3 × 1014 states cm-2 , in addition to a kinetic constant of 2.6 × 103 � −1 and 1.07 × 103 � −1 to I (3-carboxylic acid-6- mercaptopyridine) and II (Cysteine) approaches, respectively, were used in the present study. Results suggesting a higher capacity of the pyridinium ring compound anchoring molecules (I approach) in charge conduction when compared to the II approach, which was later confirmed by conductance analysis: the I approach presented � = 6 × 10−3 � and � = 2 × 10−3 � for approach II. This work presented a theoretical-experimental approach relating the quantum physicochemical components through a new perspective based on the theoretical studies of Marcus-Buttiker and on experimental analyzes focused on the electrochemical capacitance.

[ES] El radón (222Rn) es un gas radiactivo, de origen natural, generado a partir de la desintegración radiactiva del radio (226Ra). Clasificado como elemento cancerígeno por la Organización Mundial de la Salud, es la segunda causa de cáncer de pulmón en la población. La elevada peligrosidad de este gas ha fomentado e impulsado numerosos estudios y análisis dentro del ámbito de la protección radiológica. En este contexto de avance y mejora tecnológica y dada la necesidad de estudiar el comportamiento físico del gas radón, se plantea el objetivo principal de esta investigación. La presente Tesis Doctoral se basa en un análisis del comportamiento difusivo del gas radón durante su acumulación en aire y en procesos de transferencia en los que coexisten agua y aire. En primer lugar, se describe un estudio de caso real, basado en mediciones de campo que suponen el punto de partida de la tesis y que han promovido el desarrollo de la metodología necesaria para poder implementar los ensayos a escala laboratorio. Se han llevado a cabo diferentes procedimientos experimentales que permiten monitorizar la evolución de la concentración de radón en el tiempo. Por un lado, se analiza únicamente en aire, cuando el gas se acumula en el interior de depósitos de diferentes volúmenes, y por otro, se estudia la transferencia del radón del agua al aire durante los procesos de acumulación y decaimiento, tanto en condiciones de agua en estado estático como en agitación. A partir de los resultados obtenidos de concentración de radón en aire, se determina la concentración máxima alcanzable y la tasa de emisión generada por cada fuente muestreada. Por último, el tratamiento de datos de los resultados experimentales de transferencia de radón en los ensayos agua-aire, han requerido el desarrollo de modelos dinámicos que reproducen el comportamiento del gas en las diferentes condiciones ensayadas. Esto ha permitido determinar parámetros característicos del proceso difusivo del gas radón como el coeficiente de velocidad de transferencia del gas de un medio a otro y la tasa de emanación del medio acuoso. Se han validado estos resultados mediante la comparación de las concentraciones de radón en agua y en aire estimadas a partir del modelo analítico para las diferentes condiciones ensayadas, con los valores experimentales correspondientes. El ajuste preciso de estos modelos dinámicos permite predecir las concentraciones de radón en otras condiciones de ensayo. / [CA] El radó (222Rn) és un gas radioactiu, d'origen natural, generat a partir de la desintegració radioactiva del radi (226Ra). Classificat com a element cancerigen per la Organització Mundial de la Salut, és la segona causa de càncer de pulmó en la població. L'elevada perillositat d'aquest gas ha promogut i impulsat nombrosos estudis i anàlisi en l'àmbit de la protecció radiològica. En aquest context d'avanç i millora tecnològica i degut a la necessitat d'estudiar el comportament físic del gas radó, es planteja l'objectiu principal d'aquesta investigació. Aquesta Tesis Doctoral es basa en una anàlisi del comportament difusiu del gas radó durant la seua acumulació en aire i en processos de transferència en els que estan en contacte agua i aire. En primer lloc, es descriu un estudi de cas real, basat en mesures de camp que suposa el punt de partida i que han permés el desenvolupament de la metodologia necessària per poder implementar els estudis a escala laboratori. S'han dut a terme diversos procediments experimentals que permeten monitoritzar l'evolució de la concentració de radó en funció del temps. Per una banda, s'analitzen els nivells únicament en aire, quan el gas s'acumula en l'interior de depòsits de diferents volums i per altra, per estudiar la transferència de radó de l'aigua a l'aire, tant en processos d'acumulació com de decaïment, quan l'aigua es troba en estat estàtic i en agitació. A partir dels resultats experimentals obtinguts de concentració de radó en aire, es determina la concentració màxima, i la taxa d'emissió generada per cada font mostrejada. Per últim, el tractament de les dades de de transferència de radó en els assaigs agua-aire, requereixen del desenvolupament de models dinàmics que reprodueixen el comportament del gas en les diferents condicions. Açò ha permés determinar paràmetres característics del procés difusiu del gas d'un medi a altre així com la taxa d'emanació de l'aigua. S'han validat els resultats mitjançant la comparació de les concentracions de radó en aigua i en aire, estimades a partir del model analític, amb els valors experimentals del laboratori. L'ajust precís d'aquests models dinàmics permet predir les concentracions de radó en altres condicions de mostreig. / [EN] Radon (222Rn) is a naturally occurring radioactive gas generated from radium (226Ra) decay. Classified as a carcinogen by the World Health Organization, it is the second cause of lung cancer. The hazardous nature of this gas has encouraged numerous studies and investigations within the field of radiological protection. In hits context of technological progress and improvement, according to the importance of studying radon physical behavior, the main goal of this research is proposed. This PhD thesis provides an analysis of the diffusive behavior of radon gas during its accumulation in air and in transfer processes in which water and air coexist. First, a real study case is described, based on field measurements which are the starting point of the thesis and has driven the development of the methodology to be able to implement the tests at laboratory scale. Different experimental procedures have been carried out to evaluate the radon concentration. On the one hand, it is analyzed only in air, when the gas accumulates inside tanks of different volumes and, on the other hand, the radon transfer from water to air, during accumulation and decay processes are studied, both in conditions of water in static state and in turbulence. From the results obtained for radon concentration in air, the maximum achievable concentration and the emission rate generated by each sampled source is determined. Finally, the data processing of the experimental results of radon transfer in the water-air tests has required the development of dynamic models that reproduce the gas behavior in the different conditions tested. It has been determined characteristic parameters of the diffusive process of radon gas, such as the gas transfer rate coefficient from one medium to another and the emanation rate from water to air. These results have been validated by comparing the radon concentrations in water and air, estimated from the analytical model for the different conditions tested, with the corresponding experimental values. Accurate fitting of these dynamic models allows prediction of radon concentrations under other test conditions. / Noverques Medina, A. (2022). Estudio del comportamiento del gas radón (222Rn) en los procesos de transferencia en agua y en aire [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/185792