This work characterized an in vitro 3-D neural co-culture model electrophysiologically via multi electrode arrays (MEAs), and morphologically via immunocytochemistry. Since MEA surface insulation SU-8 2000 can be used in neural micro- and multi- electrode arrays, this investigation first developed techniques to make SU-8 2000 cytocompatible. The in vitro 3-D neural co-culture model was then used to study viability and electrophysiological responses to physical injury as well as drugs known to affect network signaling. 1) SU-8 2000 cytotoxicity to neuronal cultures was linked to both poor adhesive properties and toxic components, such as solvents and photo acid generator elements. Surface treatments of oxygen plasma or parylene coating following optimal combinations of heat and isopropanol sonication showed improvement in SU-8 2000 cytocompatibility. 2) The 3-D neural networks within the 3-D co-cultures maintained considerable process outgrowth and complex 3-D structure. The cultures were viable up to three weeks in vitro with functional synaptic connections and spontaneous electrophysiological activity that was responsive to chemical modulation. This electrophysiological activity was modulated by synaptic inhibition. 3) Injury experiments demonstrated that both shear and compression loading significantly increased acute membrane permeability of cells in a strain rate dependent manner. Cell death correlated with higher membrane permeability, and shear resulted in more death than compression in these 3-D cultures. While techniques were developed for making a major micro-fabrication material cytocompatible, engineering the 3-D neural co-culture resulted in a more physiologically-representative neural tissue platform, allowing an increased understanding of structure-function relationships. Overall, this research established and characterized a neural culture system for the mechanistic study of cell growth, cell-cell and cell-matrix interactions, as well as the responses to chemical or mechanical perturbations. This is the first investigation of the network-level electrophysiological activity of 3-D dissociated cultures. This system can be used to model various pathological states in vitro, testing various reparative drugs; cell-, and tissue-engineering based strategies; as well as for pre-animal and pre-clinical testing of neural implants.

Ces travaux de thèse concernent la conception et l'étude d'algorithmes, d'une part pourprédire les quantités thermodynamiques et la structure secondaire des ARN, d'autre part pour l'alignement de séquences.Dans une première partie, nous appliquons un algorithme de Monte-Carlo pour approximer la densité d'états d'énergie des structures secondaires d'une séquence d'ARN, ou d'une hybridation de deux molécules d'ARN données. Nous montrons d'abord que la densité estimée par notre programme est aussi bonne que la densité exacte, et le temps d'exécution de notre programme est beaucoup plus rapide. Nous calculons ensuite la température de dénaturation d'une hybridation de deux molécules d'ARN. Nous montrons que nos températures de dénaturation sont plus proches des valeurs expérimentales que celles des deux autres programmes existants.Puis, dans une deuxième partie, nous implémentons un algorithme de programmation dynamique qui engendre des structures sous-optimales, dédié principalement à la prédiction des deux structures fonctionnelles des riboswitchs. Nous appliquons d'abord notre programme sur un riboswitch TPP dans lequel nous avons réussi à détecter les deux structures fonctionnelles. Nous montrons ensuite que les structures prédites par notre programme sont plus proches de la structure réelle par rapport aux cinq autres programmes existants, sur un échantillon de riboswitch purine.Enfin, dans une troisième partie, nous présentons un algorithme de recherche des alignements sous-optimaux de séquences pour améliorer la qualité d'alignement des séquences. Nous comparons d'abord nos alignement à ceux produits par l'algorithme de Needdleman-Wunsch. Nous prédissons plus d'alignements de référrence par rapport l'algorithme de Needdleman-Wunsch. Nous calculons ensuite les fréquences des paires de bases alignées et les entropies de position spécifique dans nos alignements sous-optimaux. Nous montrons que les entropies calculées à partir de notre programme sont plus corrélées que celles des autres programmes avec les positions des paires de résidus fiablement alignées selon BAliBASE.

A basic assumption in the thesis is that the expansion of production and consumption in the Swedish society during the first half of the 20th century involved market as well as consumer activities of a new kind. The thesis explores the development and practice of marketing towards consumers as a main activity of actors in the market, how it was formulated in textbooks an trade journals and followed up in the activity of two Swedish companies (Barnängen and MEA, Militärekiperingsaktiebolaget). The focus is on the period 1920-1965. In the first part the main lines of the dissertation is drawn. The second part focus on texts on marketing and the main characteristics of the period is discussed. It covers the topics of marketing, distribution, advertising and selling on a general level. In two more detailed chapters, the topics of market analysis and the marketing problems and praxis in retailing is dealt with. The third part focus on the practice in the two companies. Market research from the company of Barnängen is examined with the focus on products, groups of consumers, which technique was used, how and if recommendations were followed up in product politics or advertising. The results showed a shift in the use of techniques and product politics towards more sophisticated instruments and a closer relation to a wider market. Retailers use of marketing practice is examined in the company of MEA (Militär Ekiperings Aktiebolaget). The result showed a shift in both use of advertising and advertised products over the period 1930-1960. It was also detected a shit in the relation to the market that went from customer relation to a more anonymous consumer market. The fourth part ties the normative and practical levels together. The consequences for the consumers are also taken in for discussion. It showed that in the overall perspective a change towards a wider consumer market took place.

Le captage du CO2 en postcombustion par absorption dans des solutions aqueuses d'amines est la technologie la plus mature pour réduire les émissions de gaz à effets de serre. Cependant, les amines utilisées sont susceptibles de réagir avec l'oxygène présent dans les fumées pour former de nouveaux composés qui peuvent être émis à l'atmosphère et avoir des conséquences sur l'environnement et la santé humaine.. L'objectif de cette thèse était donc d'identifier le maximum de produits de dégradation des amines grâce au développement de différentes techniques analytiques et d'échantillonnage, notamment pour l'analyse de la phase gaz. Ainsi plus de soixante produits issus de la dégradation de la monoéthanolamine (MEA) en pilote de captage du CO2 ont été identifiés. Une trentaine de ces produits sont nouveaux, ils sont souvent issus d'une même famille comme les pyrazines ou les oxazolines ou ils peuvent être caractérisés par l'allongement de la chaine carbonée (C2 entre deux hétéroatomes à C5).Des mécanismes basés sur des réactions d'alkylation/de désalkylation, la formation d'aldéhydes ou de cétones, l'amidification, l'aldolisation, la réaction d'Eschweiler Clarke, la formation de pyridines ont été proposés pour expliquer la formation de tous les nouveaux produits de dégradation et validés, dans la plupart des cas, en mélangeant les réactifs proposés dans le mécanisme. Finalement, il a été montré que la transposition de ces schémas réactionnels à trois autres amines (N-méthylaminoéthanolamine, 1-aminopropan-2-ol, 3-aminopropan-1-ol) a permis de prédire leurs produits de dégradation. / The CO2 post-combustion capture with aqueous solutions of amines is the most mature technology to reduce greenhouse gases emissions. However chemical absorption is suffering from the degradation of amines mainly due to the presence of O2 in flue gases. Formed products, which could be rejected to atmosphere, may be detrimental to environment and human health. The aim of this thesis was to identify as many degradation products as possible thanks to the development of different sampling and analytical methods especially for gas phase analysis. Thus more than sixty products issued from monoethanolamaine (MEA) degradation were observed in pilot plant samples. Thirty of them are novel, they often belong to the same family as pyrazines or oxazolines, or they could be characterized by the increase of carbon chain lengths (C2 between two heteroatoms to C5).Mechanisms such as alkylation/dealkylation, aldehydes/ketones formation, amidification, aldolisation, Eschweiler Clarke, pyridines formation were proposed to explain the formation of novel products and were, most of the time, validated by mixing the reactants proposed in the mechanism. Finally, it has been shown that the transposition of these reactions to three other amines (N-methylaminoethanolamine, 1-aminopropan-2-ol, 3-aminopropan-1-ol) enabled us to predict their degradation products.

<p>  </p> <p>With the surge of interest in the electrification of transportation driven by global climate change, the need for powertrains using non-carbon energy sources has become more urgent than ever. The fuel cell electric vehicles (FCEVs) using polymer electrolyte membrane fuel cells (PEMFCs) have many advantages over the internal combustion engine (ICE) and other renewable energy vehicles such as high efficiency, zero-emission, fast fueling, unique power, and energy scalability (without heavy penalty from the increased mass). After three decades of intensive development, there are only several thousand FCEVs on the road, in contrast to the millions of battery electric vehicles (BEV) in use today. The biggest challenge of the widespread implantation of the PEMFCs is the cost, primarily due to the use of platinum catalysts. The high intrinsic catalyst activity exhibited using a rotating disc electrode (RDE) is rarely realized in the membrane electrode assembly (MEA), which is the core of PEMFC, due to the difference on the electrolyte(ionomer)/catalyst interfaces. Much of my Ph. D research effort is concentrated on how to reduce the Pt usage and improve the stability of catalyst to reduce the operation cost of fuel cells. Several approaches were practiced improving the performance of MEA in a fuel cell, such as optimizing the ink formulation and MEA fabrication method, enhancing proton conductivity of carbon support for catalysts, engineering the ionomer and catalyst interface via surface functionalization. Such studies unraveled the relationship between property, structure, and performance of MEA, and significantly improved the performance of MEA. Further, to reduce the cost of fuel cell operation, approaches that is to improve the stability of catalysts either in reducing Oswald ripening or limiting surface migration were practiced on developing novel catalysts. Such as doping anion into Pt and Ni alloy crystal structure, introducing PANI on catalyst surface. These approaches significantly improve the stability of catalyst and MEA. Finally, same as platinum group metal (PGM) catalysts, PGM-free catalysts as well as their MEAs were studied. A novel method of PGM-free MEA fabrication was developed which significantly reduced the thickness of catalyst layer, thus greatly reduced the mass transfer resistance. Also, a highly stable and active PGM-free catalyst was developed and can be considered as a strong competitor to replace the traditional PGM catalysts in MEA.</p>

This degree project studies the integration of carbon capture system into biomass fired combined heat and power (bio-CHP) plants. The key disturbances from bio-CHP plants include flue gas flow rate, carbon dioxide (CO2) concentration and available heat for the reboiler because the use of versatile biomass and the dynamic operation of CHP plants results in large fluctuations in the properties of flue gas and the heat input for CO2 capture. To clearly understand the impacts of these disturbances on the performance of CO2 capture, a dynamic CO2 capture model is developed in Aspen Plus Dynamics by using monoethanolamine (MEA) based chemical absorption. Proportional-Integral (PI) feedback controllers are then implemented to further study and compare the performance of the CO2 capture process under different control strategies, the performance with general control settings and fine-tuned controllers are obtained and compared, including both the control performance and system performance. The control performance includes the maximum deviation and settling time, which could reflect only the performance of the controllers.  The system performance includes Captured CO2, reboiler duty and Energy penalty per unit CO2 captured, which could reflect CO2 capture system performance. An equilibrium stage steady state model is first developed for the key components in the CO2 capture plant in Aspen Plus, consisting of the absorber, the stripper, and lean-rich heat exchanger. By sizing the components and employing the pressure driven mode, the steady state model is enabled to be a dynamic model. The disturbances about flue gas and reboiler heat are taken from a real bio-CHP plant in Sweden. Considering the higher flue gas flowrate, the model has been scaled up to meet the requirement of this bio-CHP plant. The addition of controllers are done for the flexible operation of the CO2 capture system and the controlled variables considered in this study are the percentage of CO2 absorbed in the absorber column, reboiler temperature and rich solvent flow in the stripper column. The results show the effects of fluctuations in the key influencing factors on the control performance and the system performance . The fine-tuned controller implemented system showcases better performance when the quantity of CO2 captured is compared with that of the system in the absence of controllers, where a 1.1% increase in the amount of captured CO2 is observed when the flue gas flow rate is increased by 30%. The system also maintains a 1.8% higher capture rate when controllers are implemented. This showcases better system performance when controllers are implemented in the system. To further analyse the effects of control strategies two different control strategies are compared where controllers with general settings are compared to the controllers which are fine-tuning achieved by implementing tuning parameters which were obtained through Internal Model control (IMC) based on the system requirements. The fine tuning of the controllers results in improved system performance where the amount of captured CO2 increases by 1.4% when the reboiler duty is increased by 30% and a 1.7% decrease in the energy penalty per unit CO2 captured. Additionally, the results show that the settling time and maximum deviation are different for the two controllers where the controller which underwent fine tuning maintained the steady set point whereas the controller with general controller tuning showcases deviation before it attained stability. Therefore, the fine-tuned controller is more efficient to enable the flexible operation of CO2 capture when facing disturbance. It is studied that the tuning parameters implemented in the controllers affect the transient operation of the plant and improved the dynamic performance of the capture system. The tuned controllers offered more stability to the capture system while attaining their respective set points in a shorter time frame. It is also found that there exists a big difference between the system’s performance without controllers and that with finely tuned controllers. The difference in captured CO2 amount is approximately 26 ton/h when flue gas flow rate increases by 30%. The percentage difference is 1.1%, 7.7% and  5.9% for Captured CO2, reboiler duty and Energy penalty per unit CO2 captured respectively. In conclusion the control of the transient operation of the CO2 capture system needs the control system implemented and requires fine tuning parameters to achieve the desirable performance.

No description available.

It would be of great value to have a precise and non-damaging neuromodulation technique in the field of basic neuroscience research and for clinical treatment of neurological diseases. Infrared neural modulation (INM) is a new modulation modality developed in the last decade, which uses pulsed or continues infrared (IR) light with a wavelength of 1200 to 2200 nm to directly alter neural signals. INM includes both infrared neural stimulation (INS) and infrared neural inhibition (INI). INM is widely investigated for use on peripheral nerves, cochlear nerve fibers, cardiac cells, and the central nervous system. This technique holds the advantages of contact-free and high spatiotemporal precision compared to the traditional electrical stimulation. It does not depend on genetic modification and exogenous absorbers as other optical techniques, such as the optogenetic technique and the enhanced near-infrared neural stimulation (e-NIR). These advantages make INM a viable technique for research and clinical applications. The primary mechanism of the INM is believed to be a photothermal effect, where the IR laser energy absorbed by water leads to a rapid local temperature change. However, so far the details of the mechanism of action potential (AP) generation and inhibition remain elusive. Another issueis that the cells may be endangeredbythe heat exposure, consequently triggering a physiologicalmalfunction or even permanent damage.These concernshave hindered the transfer of the INM technique to the clinical therapy.Therefore, the general aim of this study was to improve the understanding of the details of how INM affects the cells. Laser parameters for safe and efficient stimulation were investigated on the basis of being useful for clinical applications. A tailored heating model and in vitro INM experiments on cortex neurons were used to reach this goal.The first paper was a feasibility study. A 1550nm laser with a beam spot diameter of around 6 mm was used to irradiate the rat cortex neurons, which were seeded on multi-electrode arrays (MEA) and formed well-connected networks. A heating model based on an estimated laser beam (standard Gaussian distribution) was used to simulate temperaturechanges. The damage signal ratio (DSR),based on the temperature,was calculated to predict the heat damage. The average spike rate of all the working electrodes from two MEAs was used to evaluate the degree of theinhibition of the neural networks. Results IVshowed that it is possible to use the 1550 nm laser to safely inhibit the neural network activity and that the degree of the INI is dependent on the power of the laser.The second paper wasan application and mechanism study. The aim of this study was to investigate the safety, efficiency, and cellular mechanism of INI. The same laser as in paper Iwas used in this study. A 20 X objective was used to decrease the beam spot diameteraround 240 μm. The measured laser profile (high order Gaussian beam) was used in the heating model to predict the temperature. The model was verified by local temperature measurements viamicropipette. The action potential rates, measured by the MEA electrodes, were quantified for different temperatures. Bicuculline was added to the cortex neuron cultures to induce hyperexcitation of the neural network. The results showed that the INI is temperature dependent and that the temperature needs to be less than 46 °C at 30 s laser irradiation for safe inhibition. The IR laser couldalso be used to inhibit the hyperexcitedactivity. The degree of inhibition, for the assessed subpopulation of neurons, was better correlated with the action potential amplitude than the width of it and INIcan be accomplished without inhibitory synapses / <p>QC 20180920</p><p></p>

Bioimpedance presents a versatile, label-free means of monitoring biological cells and their responses to physical, chemical and biological stimuli. Breast cancer is the second most common type of cancer among women in the United States. Although significant progress has been made in diagnosis and treatment of this disease, there is a need for robust, easy-to-use technologies that can be used for the identification and discrimination of critical subtypes of breast cancer in biopsies obtained from patients. This dissertation makes contributions in three major areas towards addressing the goal. First, we developed miniaturized bioimpedance sensors using MEMS and microfluidics technology that have the requisite traits for clinical use including reliability, ease-of-use, low-cost and disposability. Here, we designed and fabricated two types of bioimpedance sensors. One was based on electric cell-substrate impedance sensing (ECIS) to monitor cell adhesion based events and the other was a microfluidic device with integrated microelectrodes to examine the biophysical properties of single cells. Second, we examined a panel of triple negative breast cancer (TNBC) cell lines and a hormone therapy resistant model of breast cancer in order to improve our understanding of the bioimpedance spectra of breast cancer subtypes. Third, we explored strategies to improve the sensitivity of the microelectrodes to bioimpedance measurements from breast cancer cells. We investigated nano-scale coatings on the surface of the electrode and geometrical variations in a branched electrode design to accomplish this. This work demonstrates the promise of bioimpedance technologies in monitoring diseased cells and their responses to pharmaceutical agents, and motivates further research in customization of this technique for use in personalized medicine. / Ph. D.

Diese Dissertation befasst sich mit der industrienahen Herstellung von Katalysatorschichten für Polymer-Elektrolyt-Membran-Brennstoffzellen mit Hilfe des Tiefdrucks als Fertigungsverfahren. Um die Anforderungen an die Katalysatorschicht hinsichtlich der Schichtdicke zu erreichen, wird ein Linienraster für den Tiefdruck entwickelt. Das patentierte und verifizierte Designkonzept des Linienrasters ermöglicht es, trotz Tinten mit geringem Feststoffgehalt hohe Trockenschichtdicken zu erzeugen. Aufgrund des verwendeten Tiefdruckrasters sind Optimierungsschritte an der Fertigungsanlage notwendig, um eine hohe Schichtqualität zu erreichen. Schließlich werden kontinuierlich und industrienah Katalysatorschichten gefertigt, die als Membran-Elektroden-Einheit in einer Polymer-Elektrolyt-Membran-Brennstoffzelle erfolgreich eingesetzt werden. / This work presents an industrial close manufacturing process of active electrodes for Polymer Electrolyte Fuel Cells utilizing an adapted gravure printing process. To meet the requirements of the electrodes regarding the layer thickness (weight) and quality a novel line screen with maximized dipping volume for gravure printing was developed and investigated. A design rule for this kind of screens was realized and verified by a successful manufacturing of electrodes with different dried layer thicknesses. Due to the rough structure and the high dipping volumes of these line screens an adaption and optimization of the machinery and the whole process was necessary to achieve high quality electrodes. Finally, it is shown that it is possible to manufacture continuiously in an industrial close roll-to-roll process platinum loaded electrodes, working successful as cathode in a Membran-Electrode-Assembly.