Modeling complex cellular systems: from differential equations to constraint-based models

In the beginning of the 20th century, scientists realized the necessity of purifying enzymes to unravel their mechanistic nature. A century and tremendous progresses in the natural sciences later, molecular and systems biology became fundamental pillars of modern biology. Moreover, natural scientists developed an increasing interest in theoretical models. In the first part of my thesis, I present my contribution to the field of studying the dynamics of biological phenomena. I present fundamental issues arising, when neglecting substrate inhibition in kinetic modeling. Furthermore, I describe a model that considers experimental data to simulate the transition of normal proliferating into cellular senescent cells. Since large-scaled models are more comprehensive, they commonly prohibit a mechanistic modeling approach. In order to analyze such models, nevertheless, constraint-based methods proved to be suitable tools. In the second part of my thesis, I contribute three studies to constraint-based modeling. I describe the established concept of elementary flux modes, which resemble non-decomposable and theoretically feasible pathways of metabolic networks. Subsequently, I present the analysis of the nitrogen metabolism network of Chlamydomonas reinhardtii with respect to circadian regulation, which gives rise to about three million elementary flux modes. In the last study, I present a comprehensive work on metabolic costs of amino acid and protein production in Escherichia coli. These costs were manually calculated as well as based on a flux balance analysis of an E. coli genome-scale metabolic model. Both approaches, either dynamic or constraint-based modeling, proved to be suitable strategies to describe biological processes at different levels. Whereas dynamic modeling allowed for a precise description of the temporal behavior of biological species, constraint-based modeling enabled studies, where the complexity of the investigated phenomena prohibits kinetic modeling

Wolfgang Schäuble: “Europe will only work if the rules are the same for smaller and bigger member states”

Germany has had a central role in shaping the policies that have been implemented to address the Eurozone crisis and the persistent economic problems faced by European countries in its aftermath. Following a recent lecture at LSE, Germany’s finance minister, Wolfgang Schäuble, took questions from LSE staff and students on the need for rules to be applied consistently across all states, the impact of austerity policies on the European economy, and the UK’s upcoming referendum on EU membership

Larynxtubus beim Traumapatienten: Geeignetes Hilfsmittel für primäre Atemwegssicherung und Ventilation bei Erstversorgung und RTH-Transport?

Zusammenfassung: Ein Traumapatient wird nach primärer Sicherung der Atemwege mittels Larynxtubus mit dem Rettungshubschrauber (RTH) transportiert. Während des Fluges erfolgt die kontrollierte maschinelle Beatmung komplikationslos und ohne klinische Hinweise für eine Regurgitatio

Happy Button, die Zukunft der Geburtshilfe? : praxisrelevante Unterschiede zwischen der i. v. Remifentanil-PCA und der i. m. Pethidin-Injektion in Bezug auf die Schmerzlinderung, die Notwendigkeit einer PDA und den Geburtsmodus

Hintergrund: Im deutschsprachigen Raum ist Pethidin das am häufigsten verwendete Opioid unter der Geburt. Dem gegenüber steht Remifentanil, ein weiteres Opioid, welches in Form von patientengesteuerter Analgesie (PCA) verabreicht wird. Dieses gewinnt als «Happy Button» in der Schweizer Geburtshilfe zunehmend an Popularität. Ziel: Das Ziel dieses Literaturreviews ist es, die Unterschiede zwischen der intravenösen Remifentanil-PCA und der intramuskulären Pethidin-Injektion unter der Geburt aufzuzeigen, hinsichtlich der Schmerzlinderung, der Notwendigkeit einer PDA und des Geburtsmodus. Der Fokus liegt darauf, der Gebärenden eine ausreichende Schmerzlinderung zu bieten, welche möglichst wenige Folgeinterventionen hervorruft. Methodik: Zur Beantwortung der Fragestellung wurde anhand festgelegter Keywords in verschiedenen Datenbanken nach themenrelevanter Literatur recherchiert. Zwei quantitative Studien sowie eine Metaanalyse erfüllten die vordefinierten Ein- und Ausschlusskriterien und wurden analysiert und kritisch diskutiert. Ergebnisse: Die intravenöse Remifentanil-PCA ist der intramuskulären Pethidin-Injektion bezüglich der Schmerzlinderung, der Notwendigkeit einer PDA und der Rate an vaginaloperativen Geburtsbeendigungen überlegen. Schlussfolgerungen: Die Analgesie mit Pethidin ist, verglichen mit der Remifentanil-PCA, für viele Frauen unzureichend. Deshalb greifen sie häufiger auf eine PDA zurück, welche mit Risiken und Folgeinterventionen für Mutter und Kind verbunden ist. Durch die Umgehung einer PDA kann der physiologische Geburtsprozess besser gefördert werden

Cross-border Mobility for Electric Vehicles: Selected results from one of the first cross-border field tests in Europe

This book provides selected results from the accompanying research of the project CROME. The vision of the project was to create and test a safe, seamless, user-friendly and reliable mobility with electric vehicles between France and Germany as a prefiguration of a pan-European electric mobility system. Major aims were contributions to the European standardisation process of charging infrastructure for electric mobility and corresponding services, and to provide an early customer feedback

Impacts of Electricity Consumers’ Unit Commitment on Low Voltage Networks

Todays electricity consumer tend to become small businesses as they invest in their own decentralized electricity generation and stationary electricity storage as well as in information technology (IT) to connect and organize these new devices. Furthermore, the installed IT allows them at least technically to establish local markets. The variety of consumers and their characteristics implies numerous ways of how they optimize their individual unit commitment. This paper aims to analyze the impact of the individual consumers decisions on a future electricity demand and feed-in on low voltage network level. Therefore, in a first step the different unit commitment problems of the different small businesses have been modeled using linear programming (LP). In a second step these consumers are modeled as learning agents of a multi-agent system (MAS). The MAS comprises a local electricity market in which participants negotiate supply relationships. Finally, using scenarios with different input parameters the resulting impact is studied in detail. Amongst others, the simulations’ results show major changes in electricity demand and feed-in for scenarios with high market penetration of storages

Silica passivation layer on aluminium brazing sheets

Abstract The request for more efficient fuel economy to save raw materials and to reduce air pollution becomes more and more crucial in the automotive industry. To fulfil this demand by weight reduction, conventional materials such as steel and copper are replaced by light metals. Due to its beneficial material properties e. g. low density, high strength, good formability and high thermal conductivity, aluminium becomes a frequently used candidate. Particularly in the heat-exchanger industry this change has already taken place. Heat-exchangers made of aluminium brazing sheets are used in various applications e. g. climate control, engine and transmission cooling and charge air cooling. Brazing sheets consist of a multilayer alloy system. A typical material combination in this field is an Al-Mn core alloy (AA3xxx) clad on one or both sides with an Al-Si alloy (AA4xxx). The benefit for this combination is given by the difference in the melting points of the two alloys. During the brazing process (around 590 °C) the core alloy provides structural integrity while the low melting point clad alloy melts and flows to provide upon cooling metallic bonding between the various components of the heat-exchanger. Due to the various conditions that a heat-exchanger is exposed to during its service life such as heating and cooling cycles, salt water environment on the surface and mechanical loading, the corrosion performance is a crucial point since it might cause perforation of the material resulting in a complete failure of the system. In order to understand the corrosion behaviour of the brazing sheets, it is necessary to have a deeper look at the microstructure, which is mainly determined by the composition of the alloying elements and heat treatments. The addition of alloying elements such as copper and iron provides beneficial material properties e. g. strength, good formability and brazeability, but can also change the corrosion mechanism from pitting, which is the preferred attack in pure aluminium, to more aggressive forms of localized attack, like intergranular and exfoliation corrosion. Furthermore thermal treatments such as solution heat treatment, aging, homogenisation or brazing significantly change the microstructure and hence modify the corrosion behaviour. To fulfil the requested corrosion performance, which is usually performed by salt spray testing (SWAAT), it is often necessary to apply a pre-treatment on the heat-exchanger. Besides protecting the aluminium brazing sheet of corrosion attack, the pre-treatment has to contain environmental friendly and low costs components. After accelerated corrosion testing of AA4045/3003/4045 brazing sheets by SWAAT and electrochemical techniques, the corrosion propagation was attributed to potential differences within the brazing sheet causing a galvanically driven perforation of the core material by the diffusion zone. Furthermore a correlation between the SWAAT and potentiodynamic and potentiostatic polarization measurements is observed, offering a substitution of the SWAAT by these electrochemical techniques and hence reducing the testing time from several weeks (SWAAT) to less that one day. Corrosion prevention is achieved by immersing of the brazing sheets in an aqueous sodium silicate solution. The resulting silica passivation layer consists mainly of a dense SiO2 network and provides a reduction of around 80% of the corrosion propagation during SWAAT exposure. It is shown that the barrier properties are dependent on the respective pre-treatments conditions such as bath concentrations, curing times, curing temperatures and dipping times

El motivo de consulta como puntos cardinales en la orientación de la clínica con niños/as

El  siguiente  recorrido  se  enmarca  en  el  Proyecto  de  Investigación  V  112 “Destinos de(s)ubjetivación en infancia/s y adolescencia/s, intersecciones y comunidad”, dirigido por la Dra. Patricia V. Weigandt y Codirigido por la Lic. y Prof. Marina La Vecchia (CURZA-UNCo).  A  partir  del  presente  escrito,  se pretende  reflexionar  y  generar  la  apertura  de preguntas  en  torno  a  la  trascendencia  de  las primeras  entrevistas  en  el  marco  de  la  clínica psicopedagógica  y  el  lugar  que  ocupa  el  motivo  de consulta  como  guía  en  el  devenir  del tratamiento.  A  los  fines  anteriormente  descriptos,  se  realiza el  desarrollo  del  caso  de  un niño  pequeño  y  el  desenvolvimiento  de  los  primeros  encuentros tanto  con  él  como  son  su madre y padre. A partir del relato, el trabajo se vale de conceptualizaciones psicoanalíticas tales  como  complejo  de  Edipo,  metáfora  paterna,  Fort-Da  y  pulsiones,  que  entre otros colaboran en el análisis que requiere la teorización y revisión de la práctica clínica, en este caso, práctica clínica psicopedagógica con orientación psicoanalítica

Psicoanálisis y género/s

La presente investigación ahonda en el posi­cionamiento que las carreras de Psicopeda­gogía (por intermedio de sus docentes e in­vestigadores) asumen frente a un padeci­miento actual como lo es la violencia de gé­nero y/o familiar y cómo impacta esto mis­mo, en las intervenciones que los futuros profesionales (estudiantes) sostienen con los niños y adolescentes con quienes deben tra­bajar ya durante sus prácticas preprofesio­nales y luego como profesionales (saber ha­cer con el malestar).