Background: The 5 subunits of native pentameric C-reactive protein (CRP) are dissociated to generate the monomeric form of CRP (mCRP) in some in vitro conditions, both physiological and non-physiological, and also in vivo. Many bioactivities of mCRP generated by urea-treatment of CRP and of mCRP generated by mutating the primary structure of CRP have been reported. The bioactivities of mCRP generated by spontaneous dissociation of CRP are largely unexplored. Methods: We purified mCRP generated by spontaneous dissociation of CRP and investigated the binding of mCRP to enzymatically-modified low-density lipoprotein (E-LDL). Results: mCRP was approximately 60 times more potent than CRP in binding to E-LDL. In the presence of the small-molecule compound phosphoethanolamine (PEt), at 37 °C, the binding of mCRP to E-LDL was enhanced <2-fold, while the binding of CRP to E-LDL was enhanced >10-fold. In contrast, PEt inhibited the binding of both CRP and mCRP to pneumococcal C-polysaccharide, another phosphocholine-containing ligand to which CRP and mCRP were found to bind. We have not investigated yet whether PEt alters the structure of CRP at 37 °C. Conclusions: Combined data suggest that the targeting of CRP with the aim to monomerize CRP in vivo may be an effective approach to capture modified forms of LDL.

To develop a high performant web service in Java, Reactive WebFlux has previously been utilized as the only alternative. With the introduction of virtual threads in Java 19, it has been considered that it would be an alternative to the current provided option. This paper presents the performance difference between Spring applications powered by normal threads, virtual threads, and its reactive counterpart Reactive WebFlux. The tests were done by creating three prototypes, which were used to call an endpoint with a set delay time and increasing the number of requests per second until system failure. The results show that the virtual threaded prototypes performed slightly better than the reactive prototype. The question remains whether the Reac- tive WebFlux application using the most optimal web server produces a different re- sult, as well as future research on how virtual threads perform with database usage. / För att utveckla högpresterande webbtjänster i Java har Reactive WebFlux varit det främsta alternativet. Med introduktionen av virtuella trådar i Java 19 har spekulerats kunna ersätta reaktiva webbtjänster. Detta arbete presenterar prestandaskillnaden mellan Spring-applikationer som drivs av normala trådar, virtuella trådar och dess reaktiva motsvarighet Reactive WebFlux. Testerna utfördes genom att skapa tre pro- totyper, som användes för att anropa en slutpunkt med en satt fördröjningstid och öka antalet förfrågningar per sekund fram till systemfel. Resultaten visade att proto- typen med virtuella trådar presterade något bättre än den reaktiva prototypen. Där- emot är det ännu oklart om Reactive WebFlux-applikationen med en optimal webb- server skulle producera ett annat resultat. Dessutom skulle det vara intressant för framtida forskning om hur virtuella trådar fungerar med databasanvändning.

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[ES] Uno de los desaf&#305;&#769;os de la robótica es desarrollar sistemas de control capaces de obtener rápidamente respuestas adecuadas e inteligentes para los cambios constantes que tienen lugar en entornos dinámicos. Esta respuesta debe ofrecerse almomento con el objetivo de reanudar la ejecución del plan siempre que se produzca un fallo en el mismo.El término planificación reactiva aborda todos los mecanismos que, directa o indirectamente, promueven la resolución de fallos durante la ejecución del plan. Los sistemas de planificación reactiva funcionan bajo un enfoque de planificación y ejecución continua, es decir, se intercala planificación y ejecución en entornos dinámicos. Muchas de las investigaciones actuales se centran en desarrollar planificadores reactivos que trabajan en escenarios de un único agente para recuperarse rápidamente de los fallos producidos durante la ejecución del plan, pero, si esto no es posible, pueden requerirse arquitecturas de múltiples agentes y métodos de recuperación más complejos donde varios agentes puedan participar para solucionar el fallo. Por lo tanto, los sistemas de planificación y ejecución continua generalmente generan soluciones para un solo agente. La complejidad de establecer comunicaciones entre los agentes en entornos dinámicos y con restricciones de tiempo ha desanimado a los investigadores a implementar soluciones reactivas donde colaboren varios agentes. En línea con esta investigación, la presente tesis doctoral intenta superar esta brecha y presenta un modelo de ejecución y planificación reactiva multiagente que realiza un seguimiento de la ejecución de un agente para reparar los fallos con ayuda de otros agentes. En primer lugar, proponemos una arquitectura que comprende un modelo general reactivo de planificación y ejecución que otorga a un agente capacidades de monitorización y ejecución. El modelo también incorpora un planificador reactivo que proporciona al agente respuestas rápidas para recuperarse de los fallos que se pueden producir durante la ejecución del plan. Por lo tanto, la misión de un agente de ejecución es monitorizar, ejecutar y reparar un plan, si ocurre un fallo durante su ejecución. El planificador reactivo está construido sobre un proceso de busqueda limitada en el tiempo que busca soluciones de recuperación para posibles fallos que pueden ocurrir. El agente genera los espacios de búsqueda en tiempo de ejecución con una construcción iterativa limitada en el tiempo que garantiza que el modelo siempre tendrá un espacio de búsqueda disponible para atender un fallo inmediato del plan. Por lo tanto, la única operación que debe hacerse es buscar en el espacio de búsqueda hasta que se encuentre una solución de recuperación. Evaluamos el rendimiento y la reactividad de nuestro planificador reactivo mediante la realización de dos experimentos. Evaluamos la reactividad del planificador para construir espacios de búsqueda dentro de un tiempo disponible dado, asi como támbien, evaluamos el rendimiento y calidad de encontrar soluciones con otros dos métodos deliberativos de planificación. Luego de las investigaciones de un solo agente, propusimos extender el modelo a un contexto de múltiples agentes para la reparación colaborativa donde al menos dos agentes participan en la solución final. El objetivo era idear un modelo de ejecución y planificación reactiva multiagente que garantice el flujo continuo e ininterrumpido de los agentes de ejecución. El modelo reactivo multiagente proporciona un mecanismo de colaboración para reparar una tarea cuando un agente no puede reparar la falla por sí mismo. Para evaluar nuestro sistema, diseñamos diferentes situaciones en tres dominios de planificación del mundo real. Finalmente, el documento presenta algunas conclusiones y también propone futuras l&#305;&#769;neas de investigación posibles. / [CA] Un dels desafiaments de la robòtica és desenvolupar sistemes de control capaços d'obtindre ràpidament respostes adequades i intel·ligents per als canvis constants que tenen lloc en entorns dinàmics. Aquesta resposta ha d'oferir-se al moment amb l'objectiu de reprendre l'execució del pla sempre que es produ&#305;&#776;sca una fallada en aquest. El terme planificació reactiva aborda tots els mecanismes que, directa o indirectament, promouen la resolució de fallades durant l'execució del pla. Els sistemes de planificació reactiva funcionen sota un enfocament de planificació i execució cont&#305;&#769;nua, és a dir, s'intercala planificació i execució en entorns dinàmics. Moltes de les investigacions actuals se centren en desenvolupar planificadors reactius que treballen en escenaris d'un únic agent per a recuperar-se ràpidament de les fallades produ&#305;&#776;des durant l'execució del pla, però, si això no és possible, poden requerir-se arquitectures de múltiples agents i mètodes de recuperació més complexos on diversos agents puguen participar per a solucionar la fallada. Per tant, els sistemes de planificació i execució cont&#305;&#769;nua generalment generen solucions per a un sol agent. La complexitat d'establir comunicacions entre els agents en entorns dinàmics i amb restriccions de temps ha desanimat als investigadors a implementar solucions reactives on col·laboren diversos agents. En l&#305;&#769;nia amb aquesta investigació, la present tesi doctoral intenta superar aquesta bretxa i presenta un model d'execució i planificació reactiva multiagent que realitza un seguiment de l'execució d'un agent per a reparar les fallades amb ajuda d'altres agents. En primer lloc, proposem una arquitectura que comprén un model general reactiu de planificació i execució que atorga a un agent capacitats de monitoratge i execució. El model també incorpora un planificador reactiu que proporciona a l'agent respostes ràpides per a recuperar-se de les fallades que es poden produir durant l'execució del pla. Per tant, la missió d'un agent d'execució és monitorar, executar i reparar un pla, si ocorre una fallada durant la seua execució. El planificador reactiu està constru&#305;&#776;t sobre un procés de cerca limitada en el temps que busca solucions de recuperació per a possibles fallades que poden ocórrer. L'agent genera els espais de cerca en temps d'execució amb una construcció iterativa limitada en el temps que garanteix que el model sempre tindrà un espai de cerca disponible per a atendre una fallada immediata del pla. Per tant, l'única operació que ha de fer-se és buscar en l'espai de cerca fins que es trobe una solució de recuperació. Avaluem el rendiment i la reactivitat del nostre planificador reactiu mitjançant la realització de dos experiments. Avaluem la reactivitat del planificador per a construir espais de cerca dins d'un temps disponible donat, aix&#305;&#769; com també, avaluem el rendiment i qualitat de trobar solucions amb altres dos mètodes deliberatius de planificació. Després de les investigacions d'un sol agent, vam proposar estendre el model a un context de múltiples agents per a la reparació col·laborativa on almenys dos agents participen en la solució final. L'objectiu era idear un model d'execució i planificació reactiva multiagent que garantisca el flux continu i ininterromput dels agents d'execució. El model reactiu multiagent proporciona un mecanisme de col·laboració per a reparar una tasca quan un agent no pot reparar la falla per si mateix. Explota les capacitats de planificació reactiva dels agents en temps d'execució per a trobar una solució en la qual dos agents participen junts, evitant aix&#305;&#769; que els agents hagen de recórrer a mecanismes deliberatius. Per a avaluar el nostre sistema, dissenyem diferents situacions en tres dominis de planificació del món real. Finalment, el document presenta algunes conclusions i tam / [EN] One of the challenges of robotics is to develop control systems capable of quickly obtaining intelligent, suitable responses for the regularly changing that take place in dynamic environments. This response should be offered at runtime with the aim of resume the plan execution whenever a failure occurs. The term reactive planning addresses all the mechanisms that, directly or indirectly, promote the resolution of failures during the plan execution. Reactive planning systems work under a continual planning and execution approach, i.e., interleaving planning and execution in dynamic environments. Most of the current research puts the focus on developing reactive planning system that works on single-agent scenarios to recover quickly plan failures, but, if this is not possible, we may require more complex multi-agent architectures where several agents may participate to solve the failures. Therefore, continual planning and execution systems have usually conceived solutions for individual agents. The complexity of establishing agent communications in dynamic and time-restricted environments has discouraged researchers from implementing multi-agent collaborative reactive solutions. In line with this research, this Ph.D. dissertation attempts to overcome this gap and presents a multi-agent reactive planning and execution model that keeps track of the execution of an agent to recover from incoming failures. Firstly, we propose an architecture that comprises a general reactive planning and execution model that endows a single-agent with monitoring and execution capabilities. The model also comprises a reactive planner module that provides the agent with fast responsiveness to recover from plan failures. Thus, the mission of an execution agent is to monitor, execute and repair a plan, if a failure occurs during the plan execution. The reactive planner builds on a time-bounded search process that seeks a recovery plan in a solution space that encodes potential fixes for a failure. The agent generates the search space at runtime with an iterative time-bounded construction that guarantees that a solution space will always be available for attending an immediate plan failure. Thus, the only operation that needs to be done when a failure occurs is to search over the solution space until a recovery path is found. We evaluated theperformance and reactiveness of our single-agent reactive planner by conducting two experiments. We have evaluated the reactiveness of the single-agent reactive planner when building solution spaces within a given time limit as well as the performance and quality of the found solutions when compared with two deliberative planning methods. Following the investigations for the single-agent scenario, our proposal is to extend the single model to a multi-agent context for collaborative repair where at least two agents participate in the final solution. The aim is to come up with a multi-agent reactive planning and execution model that ensures the continuous and uninterruptedly flow of the execution agents. The multi-agent reactive model provides a collaborative mechanism for repairing a task when an agent is not able to repair the failure by itself. It exploits the reactive planning capabilities of the agents at runtime to come up with a solution in which two agents participate together, thus preventing agents from having to resort to a deliberative solution. Throughout the thesis document, we motivate the application of the proposed model to the control of autonomous space vehicles in a Planetary Mars scenario. To evaluate our system, we designed different problem situations from three real-world planning domains. Finally, the document presents some conclusions and also outlines future research directions. / Gúzman Álvarez, CA. (2019). Reactive plan execution in multi-agent environments [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/120457

In recent years, the electric power industry around the world is changing continuously due to transformation from regulated market structure to deregulated market structure. The main aim of the transformation of electric supply industry under open access environment is to overcome the some of the limitations faced by the vertically integrated system. It is believed that this transformation will bring in new technologies, integration of other sources of energy such as wind, solar, fuel cells, bio-gas, etc., which are self sustainable and competitive, and better choice for the consumers and so on. As a result, several new issues and challenges have emerged. One of the main issues in power systems is to support reactive power for maintaining the system voltage profile with an acceptable margin of security and reliability required for system operation. In this context, the thesis addresses some of the problems related to planning and operation of reactive power in power systems. Studies are mainly focused on steady state operation of grid systems, grid connected wind farms and distribution systems as well. The reactive power support and loss allocation using Y-bus approach is proposed. It computes the reactive power contribution from various reactive sources to meet the reactive load demand and losses. Further, the allocation of reactive power loss to load or sink buses is also computed. Detailed case studies are carried out on 11-bus equivalent system of Indian southern region power grid under different loading conditions and also tested on 259-bus equivalent system of Indian western region power grid. A comparative analysis is also carried out with the proportional sharing principle and one of the circuit based approach in the literature to highlight the features of the proposed approach. A new reactive power loss index is proposed for identification of weak buses in the system. The new index is computed from the proposed Y-bus approach for the system under intact condition as well as some severe contingencies cases. Fuzzy logic approach is used to select the important and severe line contingencies from the contingency list. The validation of weak load buses identification from the proposed reactive power loss index with that from other well known existing methods in the literature such as Q-V sensitivity based modal analysis and continuation power flow method is carried out to demonstrate the effectiveness of the proposed index. Then, a short-term reactive power procurement/optimal reactive power dispatch analysis is also carried out to determine the optimum size of the reactive compensation devices to be placed at the weak buses for reactive compensation performance analysis in the system. The proposed approach is illustrated on a sample 5-bus system, and tested on sample 10-bus equivalent system and 72-bus equivalent system of Indian southern region power grid. A comprehensive power flow analysis of PQ type models for wind turbine generating units is presented. The different PQ type models of fixed/semi-variable speed wind turbine generating units are considered for the studies. In addition, the variable speed wind turbine generating units are considered in fixed power factor mode of operation. Based on these models, a comparative analysis is carried out to assess the impact of wind generation on distribution and transmission systems. 27-bus equivalent distribution test system, 93-bus equivalent test system and SR 297-bus equivalent grid connected wind system are considered for the studies. Lastly, reactive power coordination for voltage stability improvement in grid connected wind farms with different types of wind turbine generating units based on fuzzy logic approach is presented. In the proposed approach, the load bus voltage deviation is minimized by changing the reactive power controllers according to their sensitivity using fuzzy set theory. The fixed/semi-variable speed wind turbine generating units are also considered in the studies because of its impact on overall system voltage performance even though they do not support the system for voltage unlike variable speed wind generators. 297-bus equivalent and 417-bus equivalent grid connected wind systems are considered to present the simulation results. A comparative analysis is also carried out with the conventional linear programming based reactive power optimization technique to highlight the features of the proposed approach.

This master thesis is focused on analysis of reactive power flow in LV and MV networks. In the first part there is a definition of reactive power and description of individual parts of electrical networks that contribute with their reactive power to distribution network. The second part is dedicated to calculation of power flow in simulation software PSS® Sincal where on numerical models of network different types of network configuration are tested and consequently its influence on reactive power flow is evaluated. A more detailed analysis is dedicated to reactive power compensation in networks with distributed generation equipped with Volt-Var regulation and its possible negative mutual influence. This thesis also includes general recommendation on the basis of network simulation analysis concerning installation of compensating systems in distribution transformer station.

This thesis focuses on solutions of reactive transport problems in porous media. The principle mechanisms of flow and reactive mass transport in porous media are investigated. Global implicit approach (GIA), where transport and reaction are fully coupled, and sequential noniterative approach (SNIA) are implemented into the software OpenGeoSys (OGS6) to couple chemical reaction and mass transport. The reduction scheme proposed by Kräutle is used in GIA to reduce the number of coupled nonlinear differential equations. The reduction scheme takes linear combinations within mobile species and immobile species and effectively separates the reaction-independent linear differential equations from coupled nonlinear ones (i.e. reducing the number of primary variables in the nonlinear system). A chemical solver is implemented using semi-smooth Newton iteration which employs complementarity condition to solve for equilibrium mineral reactions. The results of three benchmarks are used for code verification. Based on the solutions of these benchmarks, it is shown that GIA with the reduction scheme is faster (ca. 6.7 times) than SNIA in simulating homogeneous equilibrium reactions and (ca. 24 times) in simulating kinetic reaction. In simulating heterogeneous equilibrium mineral reactions, SNIA outperforms GIA with the reduction scheme by 4.7 times. / Diese Arbeit konzentriert sich auf die numerische Berechnung reaktiver Transportprobleme in porösen Medien. Es werden prinzipielle Mechanismen von Fluidströmung und reaktive Stofftransport in porösen Medien untersucht. Um chemische Reaktionen und Stofftransport zu koppeln, wurden die Ansätze Global Implicit Approach (GIA) sowie Sequential Non-Iterative Approach (SNIA) in die Software OpenGeoSys (OGS6) implementiert. Das von Kräutle vorgeschlagene Reduzierungsschema wird in GIA verwendet, um die Anzahl der gekoppelten nichtlinearen Differentialgleichungen zu reduzieren. Das Reduzierungsschema verwendet Linearkombinationen von mobilen und immobile Spezies und trennt die reaktionsunabhngigen linearen Differentialgleichungen von den gekoppelten nichtlinearen Gleichungen (dh Verringerung der Anzahl der Primärvariablen des nicht-linearen Gleichungssystems). Um die Gleichgewichtsreaktionen der Mineralien zu berechnen, wurde ein chemischer Gleichungslaser auf Basis von ”semi-smooth Newton-Iterations” implementiert. Ergebnisse von drei Benchmarks wurden zur Code-Verifikation verwendet. Diese Ergebnisse zeigen, dass die Simulation homogener Equilibriumreaktionen mit GIA 6,7 mal schneller und bei kinetischen Reaktionen 24 mal schneller als SNIA sind. Bei Simulationen heterogener Equilibriumreaktionen ist SNIA 4,7 mal schneller als der GIA Ansatz.

Thesis (PhD)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: The reactive absorption rate of CO2 into non-aqueous solvents containing the primary amine, mono-ethanolamine (MEA) is recognised as a suitable method for measuring the effective interfacial mass transfer area of separation column internals such as random and structured packing. Currently, this method is used under conditions where the concentration of MEA in the liquid film is unaffected by the reaction and the liquid phase reaction is, therefore, assumed to obey pseudo first order kinetics with respect to CO2. Under pseudo first order conditions, the effect of surface depletion and renewal rates are not accounted for. Previous research indicated that the effective area available for mass transfer is also dependent upon the rate of surface renewal achieved within the liquid film. In order to study the effect of surface depletion and renewal rates on the effective area, a method utilising a fast reaction with appreciable depletion of the liquid phase reagent is required. The homogeneous liquid phase reaction kinetics of CO2 with MEA n-Propanol as alcoholic solvent was investigated in this study. A novel, in-situ Fourier Transform Infra-Red (FTIR) method of analysis was developed to collect real time concentration data from reaction initiation to equilibrium. The reaction was studied in a semi-batch reactor set-up at ambient conditions (T = 25°C, 30°C and 35°C, P = 1 atm (abs)). The concentration ranges investigated were [MEA]:[CO2] = 5:1 and 10:1. The concentration range investigated represents conditions of significant MEA conversion. The reaction kinetic study confirmed the findings of previous research that the reaction of CO2 with MEA is best described by the zwitterion reactive intermediate reaction mechanism. Power rate law and pseudo steady state hypothesis kinetic models (proposed in literature) were found to be insufficient at describing the reaction kinetics accurately. Two fundamentally derived rate expressions (based on the zwitterion reaction mechanism) provided a good quality model fit of the experimental data for the conditions investigated. The rate constants of the full fundamental model were independent of concentration and showed an Arrhenius temperature dependence. The shortened fundamental model rate constants showed a possible concentration dependence, which raises doubt about its applicability. The specific absorption rates (mol/m2.s) of CO2 into solutions of MEA/n-Propanol (0.2 M and 0.08 M, T = 25°C and 30°C, P = ±103 kPa) were investigated on a wetted wall experimental setup. The experimental conditions were designed for a fast reaction in the liquid film to occur with a degree of depletion of MEA in the liquid film. Both interfacial depletion and renewal of MEA may be considered to occur. The gas phase resistance to mass transfer was determined to be negligible. An increase in liquid turbulence caused an increase in the specific absorption rate of CO2 which indicated that an increase in liquid turbulence causes an increase in effective mass transfer area. Image analysis of the wetted wall gas-liquid interface confirmed the increase in wave motion on the surface with an increase in liquid turbulence. The increase in wave motion causes an increase in both interfacial and effective area. A numerical solution strategy based on a concentration diffusion equation incorporating the fundamentally derived rate expressions of this study is proposed for calculating the effective area under conditions where surface depletion and renewal rates are significant. It is recommended that the reaction kinetics of CO2 with MEA in solvents of varying liquid properties is determined and the numerical technique proposed in this study used to calculate effective area from absorption rates into these liquids. From the absorption data an effective area correlation as a function of liquid properties may be derived in future. / AFRIKAANSE OPSOMMING: Die reaktiewe absorpsie van CO2 in nie-waterige oplossings van die primêre amien, monoetanolamien (MEA) word erken as ‘n geskikte metode om die effektiewe massaoordragsarea van gepakte skeidingskolomme te bepaal. Tans word die metode gebruik onder vinnige pseudo eerste orde reaksietoestande met betrekking tot CO2. Die pseudo eersteorde aanname beteken dat die konsentrasie van MEA in die vloeistoffilm onbeduidend beïnvloed word deur die reaksie en effektief konstant bly. Onder pseudo eerste orde toestande word oppervlakverarming- en oppervlakvernuwingseffekte nie in ag geneem nie, juis as gevolg van die konstante konsentrasie van MEA in die vloeistoffilm. Daar is voorheen bevind dat oppervlakverarming en oppervlakvernuwing ‘n beduidende invloed het op die beskikbare effektiewe massaoordragsarea. Hierdie invloed kan slegs bestudeer word met ‘n vinnige reaksie in die vloeistoffilm wat gepaard gaan met beduidende oppervlakverarming van die vloeistoffase reagens. Die homogene vloeistoffase reaksiekinetika van CO2 met MEA in die alkohol oplosmiddel, n- Propanol, is in hierdie studie ondersoek. ‘n Nuwe, in-situ Fourier Transform Infra-Rooi (FTIR) metode van analiese is ontwikkel in hierdie ondersoek. Die reaksie is ondersoek in ‘n semienkelladings reaktor met MEA wat gevoer is tot die reaktor om met die opgeloste CO2 te reageer. Die FTIR metode meet spesiekonsentrasie as ‘n funksie van tyd sodat die konsentrasieprofiele van CO2, MEA en een van die soutprodukte van die reaksie gebruik kan word om verskillende reaksiesnelheidsvergelykings te modelleer. Die reaksie is ondersoek onder matige toestande (T = 25°C, 30°C and 35°C, P = 1 atm (abs)). Die konsentrasiebereik van die ondersoek was [MEA]:[CO2] = 5:1 en 10:1. Hierdie bereik is spesifiek gebruik sodat daar beduidende omsetting van MEA kon plaasvind. Die reaksiekinetieka studie het, ter ondersteuning van bestaande teorie, bevind dat die reaksie van CO2 met MEA in nie-waterige oplosmiddels soos alkohole, beskyf word deur ‘n zwitterioon reaksiemeganisme. Die bestaande reaksiesnelheids modelle (eksponensiële wet en pseudo gestadigde toestand hipotese) kon nie die eksperimentele data met genoegsame akuraatheid beskryf nie. Twee nuwe reaksiesnelheidsvergelykings, afgelei vanaf eerste beginsels en gebaseer op die zwitterioon meganisme, word voorgestel. Hierdie volle fundamentele model het goeie passings op die eksperimentele data getoon oor die volledige temperatuur en konsentrasiebereik van hierdie studie. Die reaksiekonstantes van die fundamentele model was onafhanklik van konsentrasie en tipe oplosmiddel en het ‘n Arrhenius temperatuurafhanklikheid. Die verkorte fundamentele model se reaksiekonstantes het ‘n moontlike konsentrasieafhanlikheid gewys. Dit plaas onsekerheid op die fundamentele basis van hierdie model en kan dus slegs as ‘n eerste benadering beskou word. Die spesifieke absorpsietempos (mol/m2.s) van CO2 in MEA/n-Propanol oplossings (0.2 M en 0.08 M MEA, T = 25°C and 30°C, P = ±103 kPa) is ondersoek met ‘n benatte wand (‘wetted wall’) eksperimentele opstelling. Die eksperimentele toestande is gekies sodat daar ‘n vinnige reaksie in die vloeistoffilm plaasgevind het, met beide beduidende en nie-beduidende MEA omsetting. Die doel met hierdie eksperimentele ontwerp was om die invloed van intervlakverarming en intervlakvernuwing op die spesifieke absorpsietempo te ondersoek. Gas fase weerstand was nie-beduidend onder die eksperimentele toestande nie. Beide intervlakverarming en intervlakvernuwing gebeur gelyktydig en is waargeneem vanuit die eksperimentele data. ‘n Beeldverwerkingstudie van die gas-vloeistof intervlak van die benatte wand het bevind dat daar ‘n toename in golfaksie op die vloeistof oppervlak is vir ‘n toename in vloeistof turbulensie. Hierdie golfaksie dra by tot oppervlakvernuwing en ‘n toename in effektiewe massaoordragsarea. ‘n Numeriese metode word voorgestel om die effektiewe area van beide die benatte wand en gepakte kolomme te bepaal vanaf reaktiewe absorpsietempos. Die metode gebruik die fundamentele reaksiesnelheidsvergelykings, bepaal in hierdie studie, in a konsentrasie diffusievergelyking sodat oppervlakverarming en vernuwing in ag geneem kan word. Daar word voorgestel dat die reaksiekinetika van CO2 met MEA in oplossings met verskillende fisiese eienskappe (digtheid, oppervlakspanning en viskositeit) bepaal word sodat die numeriese metode gebruik kan word om ‘n effektiewe area korrelasie as ‘n funksie van hierdie eienskappe te bepaal.

C-reactive protein (CRP) is a protein found in the blood that is synthesized by the liver and has been extensively studied due to its role in inflammatory and atherosclerotic processes. The importance of this biomarker in its role in vascular risk factors is increased with several lines of evidence pointing to its association with cognitive decline. The association between CRP and depression has been increasingly analyzed by various cross-sectional studies. The research between CRP and depressive symptoms in older women has yet to generate consistent trends. In the present study, a series of regression analyses was used to explore the association between CRP and both cognitive function and depressive symptomatology among a group of rural-dwelling women. Associations were evaluated through the use of data from Project FRONTIER, a rural-based research looking at both physical and cognitive aspects of health in rural-dwelling adults and elders. Comparisons were made between Mexican American women and a group of non-Hispanic Caucasian women. CRP was a significant independent predictor of total depression (beta = -.11, t = -1.99, p =.048). CRP was also a significant independent predictor of symptoms associated with meaningless within depression (beta = -.16, t = -2.94, p =.004). Contrary to prediction, CRP was not a significant independent predictor of overall cognitive function or performance in five specific cognitive domains. There is still needed evaluation on racial/ethnic differences present in regard to the impact of varied health factors on mental health within a culturally rich, rural cohort. It is recommended that future studies utilize standardized measurement of cognitive function to facilitate a more thorough understanding and comparison of change in this particular population.

Human C-reactive protein (CRP) is the prototypic acute phase protein whose serum concentration increases rapidly during inflammation. CRP is also associated with atherosclerosis; it is deposited at lesion sites where it may interact with modified lipoproteins. There are 2 major questions regarding CRP: 1. How is the serum concentration of CRP regulated? 2. What are the functions of CRP in atherosclerosis? Our first aim was to determine the role of the constitutively expressed transcription factor Oct-1 in regulating CRP gene expression. We found that Oct-1 overexpression inhibited (IL-6+IL-1β)- induced CRP gene expression; maximal inhibition required the binding of Oct-1 to an octamer motif at (-59 to -66) on the CRP promoter. Oct-1 overexpression inhibited both (IL-6+IL-1β)- induced and C/EBPβ-induced CRP gene expression even when the Oct-1 site was deleted. These findings suggest that Oct-1 is a repressor of CRP gene expression that acts via binding to its cognate site on the CRP promoter as well as through indirect interactions with other promoterbound transcription factors. Our second aim was to investigate the interaction of CRP with oxidized low density lipoprotein (ox-LDL). Acidic pH, a hallmark of atherosclerotic lesions, reversibly alters CRP structure and exposes a hidden binding site that enables CRP to bind ox-LDL. Using site-directed mutagenesis we constructed a CRP mutant (E42Q) that showed significant binding to ox-LDL at physiological pH. E42Q CRP required a less acidic pH for maximal binding and bound ox-LDL more efficiently than wild type CRP at any pH. We then examined if reactive oxygen species also induced CRP – ox-LDL interaction. H2O2-treated CRP bound ox-LDL at physiological pH. Like acidic pH, H2O2-treatment induced only a local structural change exposing the ox-LDL binding site. E42Q and H2O2-modified CRP are tools to study the function of CRP in animal models of atherosclerosis, which may not have an inflammatory environment sufficient to modify CRP and induce binding to atherogenic ox-LDL. We conclude that Oct-1 is one of the critical regulators of CRP gene expression, and that CRP can be modified in vitro to convert it into an atherogenic LDL-binding molecule.