Um die anderen Arten von Veröffentlichungen zu diesem Thema anzuzeigen, folgen Sie diesem Link: Reactive strategies.
Dissertationen zum Thema „Reactive strategies“
Geben Sie eine Quelle nach APA, MLA, Chicago, Harvard und anderen Zitierweisen an
Machen Sie sich mit Top-50 Dissertationen für die Forschung zum Thema "Reactive strategies" bekannt.
Neben jedem Werk im Literaturverzeichnis ist die Option "Zur Bibliographie hinzufügen" verfügbar. Nutzen Sie sie, wird Ihre bibliographische Angabe des gewählten Werkes nach der nötigen Zitierweise (APA, MLA, Harvard, Chicago, Vancouver usw.) automatisch gestaltet.
Sie können auch den vollen Text der wissenschaftlichen Publikation im PDF-Format herunterladen und eine Online-Annotation der Arbeit lesen, wenn die relevanten Parameter in den Metadaten verfügbar sind.
Sehen Sie die Dissertationen für verschiedene Spezialgebieten durch und erstellen Sie Ihre Bibliographie auf korrekte Weise.
1
Zeng, Zhen [Verfasser], Albert [Akademischer Betreuer] Gollhofer und Daniel [Akademischer Betreuer] König. „Effects of dietary strategies on reactive oxygen species production“. Freiburg : Universität, 2021. http://d-nb.info/1237617979/34.
Der volle Inhalt der Quelle
2
Perdigão, José Nuno Bebiano Mesquita de Azeredo. „Reactive-control strategies for an oscillating-water-column device“. Phd thesis, Instituições portuguesas -- UTL-Universidade Técnica de Lisboa -- IST-Instituto Superior Técnico -- -Departamento de Engenharia Mecânica, 1998. http://dited.bn.pt:80/29667.
Der volle Inhalt der Quelle
3
Landgren, Emma, und Martina Lidberg. „Managing negative eWOM in the retail industry : A qualitative study of proactive and reactive strategies“. Thesis, Umeå universitet, Företagsekonomi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-185339.
Der volle Inhalt der QuelleAnnotation:
In the fast pace of the development of the Internet and the increased use of it more and more people use interactive platforms to connect with each other. The increased opportunity and ability to share content with people around the globe has led to the emergence of eWOM. eWOM means that consumers generate content that is consumption-related and mainly directed towards other consumers. Today, social media sites are the biggest source to eWOM. Consumers are actively searching for eWOM in order to gain information and reduce uncertainty, as a part of their purchasing process. In general, consumers tend to trust consumer generated content more than marketer generated content. Therefore, eWOM becomes a crucial component to business performance. Negative eWOM has been shown to affect the purchase intentions, loyalty and trust in a negative way, which eventually affects the turnover for a company. Negative eWOM has further been seen to have a larger impact on consumers, compared to positive eWOM. These consequences emphasize the importance of marketers being aware of negative eWOM and have strategies to manage it. The subject of eWOM has been acknowledged by practitioners and researchers. However, despite the increased interest in eWOM and its effects on business performance, there are still research gaps on how to proactively and reactively avoid and manage negative eWOM. The purpose of this study was to examine and understand what strategies companies use in order to avoid and manage negative eWOM on company owned and external interactive platforms. To fill the identified research gaps, this study took an inductive approach and the authors conducted a qualitative study using semi-structured interviews. The sample was purposively selected to include respondents within different companies that had knowledge about the companies’ strategies and approach towards managing negative eWOM. The sample consisted of companies of different sizes, which provided different perspectives and rich information of how companies can approach negative eWOM. A thematic analysis was conducted in order to analyze the empirical data and present relevant findings from the data collection. As a result of the thematic analysis, two global themes were identified: proactive strategies and reactive strategies. Within the global theme proactive strategies, five sub- themes were found: observation, detect critical potential scenarios and questions, communicate expectations, encourage feedback and facilitate contact. Within the global theme reactive strategies, six sub-themes were found: acknowledge or leave, do not delete, accommodative, defensive, answer in public, drive to private, and humorous and cleverly. These themes laid the foundation for a final conceptual model. The findings of this study suggest that marketers in retail use different proactive strategies to avoid negative eWOM from occurring in the first place. Moreover, the findings of this study show that marketers in retail, depending on the content of the negative eWOM and the platform it is taking place on, also use different reactive strategies to manage negative eWOM. The results also show that what strategy to use is to a large extent dependent on the individual’s subjective ability to interpret the negative eWOM.
4
Ritz, Mariah. „Strategies to Manage Noncompliance in Preschool Classrooms“. Miami University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=miami1370860439.
Der volle Inhalt der Quelle
5
Unosson, Erik. „Antibacterial Strategies for Titanium Biomaterials“. Doctoral thesis, Uppsala universitet, Tillämpad materialvetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-249181.
Der volle Inhalt der QuelleAnnotation:
Titanium and titanium based alloys are widely used in dentistry and orthopedics to replace hard tissue and to mend broken bones. It has become a material of choice due to its low density, high strength, good biocompatibility and its capacity to integrate closely with the bone. Today, modern materials and surgical techniques can enable patients to live longer, and aid in maintaining or regaining mobility for a more fulfilling life. There are, however, instances where implants fail, and one of the primary causes for implant failure is infection. This thesis deals with two possible ways of reducing or eliminating implant associated infections; TiO2 photocatalysis, where a surface can become antibacterial upon irradiation with UV light; and incorporation of silver, where a subsequent release of silver metal ions result in an antibacterial effect. For the TiO2 photocatalysis strategy, a simple and cost effective chemical oxidation technique, using hydrogen peroxide (H2O2) and water, was used to create an active TiO2 surface on titanium substrates. This surface was shown to effectively degrade an organic model substance (rhodamine B) by generating reactive oxygen species (ROS) under UV illumination. However, it was shown that Ti-peroxy radical species remaining in the surface after the H2O2-oxidation process, rather than generation of ROS from a heterogeneous photocatalytic process, was responsible for the effect. This discovery was further exploited in a TiO2/H2O2/UV system, which demonstrated synergy effects in both rhodamine B degradation tests and in antibacterial assays. For the silver ion release strategy, a combinatorial materials science approach was employed. Binary Ag-Ti oxide gradients were co-deposited in a reactive (O2) environment using a custom built physical vapor deposition system, and evaluated for antibacterial properties. The approach enabled synthesis and composition-structure-property evaluation unlikely to have been achieved by traditional means, and the gradient coatings demonstrated antibacterial properties against both S. aureus and S. epidermidis according to silver ion release. The release was shown to depend more on structural features, such as surface area, crystallinity and oxidation state, than on composition. Ag-Ti oxide gradients were also evaluated under UV illumination, as Ag deposits on crystalline TiO2 can enhance photocatalytic properties. In this work, however, the TiO2 was amorphous and UV illumination caused a slight reduction in the antibacterial effect of silver ions. This was attributed to a UV-induced SOS response in the S. epidermidis bacteria. The results of this thesis demonstrate that both TiO2 photocatalysis, or UV induced activation of Ti-peroxy radical species, as well as incorporation of silver are viable antibacterial strategies for titanium biomaterials. However, their clinical applications are still pending risk-benefit analyses of potential adverse host tissue responses.
6
Addiego-Guevara, Ernesto. „Quantifying the value of reactive and proactive feedback control strategies for intelligent wells“. Thesis, Imperial College London, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.516180.
Der volle Inhalt der Quelle
7
Tudoroiu, Nicolae. „Application of multivariable and intelligent control strategies for improving plasma characteristics in reactive ion etching“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ59229.pdf.
Der volle Inhalt der Quelle
8
Henkes, Amanda Erin. „Solution-mediated strategies for synthesizing metal oxides, borates and phosphides using nanocrystals as reactive precursors“. [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-2674.
Der volle Inhalt der Quelle
9
Wu, Hao. „Numerical Investigations of Geologic CO2 Sequestration Using Physics-Based and Machine Learning Modeling Strategies“. Diss., Virginia Tech, 2020. http://hdl.handle.net/10919/99604.
Der volle Inhalt der QuelleAnnotation:
Carbon capture and sequestration (CCS) is an engineering-based approach for mitigating excess anthropogenic CO2 emissions. Deep brine aquifers and basalt reservoirs have shown outstanding performance in CO2 storage based on their global widespread distribution and large storage capacity. Capillary trapping and mineral trapping are the two dominant mechanisms controlling the distribution, migration, and transportation of CO2 in deep brine aquifers and basalt reservoirs. Understanding the behavior of CO2 in a storage reservoir under realistic conditions is important for risk management and storage efficiency improvement. As a result, numerical simulations have been implemented to understand the relationship between fluid properties and multi-phase fluid dynamics. However, the physics-based simulations that focus on the uncertainties of fluid flow dynamics are complicated and computationally expensive. Machine learning method provides immense potential for improving computational efficiency for subsurface simulations, particularly in the context of parametric sensitivity. This work focuses on parametric uncertainty associated with multi-phase fluid dynamics that govern geologic CO2 storage. The effects of this uncertainty are interrogated through ensemble simulation methods that implement both physics-based and machine learning modeling strategies. This dissertation is a culmination of three projects: (1) a parametric analysis of capillary pressure variability effects on CO2 migration, (2) a reactive transport simulation in a basalt fracture system investigating the effects of carbon mineralization on CO2 migration, and (3) a parametric analysis based on machine learning methods of simultaneous effects of capillary pressure and relative permeability on CO2 migration.Doctor of Philosophy
Carbon capture and sequestration (CCS) has been proposed as a technological approach to mitigate the deleterious effects of anthropogenic CO2 emissions. During CCS, CO2 is captured from power plants and then pumped in deep geologic reservoirs to isolate it from the atmosphere. Deep sedimentary formations and fractured basalt reservoirs are two options for CO2 storage. In sedimentary systems, CO2 is immobilized largely by physical processes, such as capillary and solubility trapping, while in basalt reservoirs, CO2 is transformed into carbonate minerals, thus rendering it fully immobilized. This research focuses on how a large range of capillary pressure variabilities and how CO2-basalt reactions affect CO2 migration. Specifically, the work presented utilizes numerical simulation and machine learning methods to study the relationship between capillary trapping and buoyancy in a sandstone formation, as well as the combined effects of capillary pressure and relative permeability on CO2 migration. In addition, the work also identifies a new reinforcing feedback between mineralization and relative permeability during reactive CO2 flow in a basalt fracture network. In aggregate, the whole of this work presents a new, multi-dimensional perspective on the multi-phase fluid dynamics that govern CCS efficacy in a range of geologic formations.
10
Niemeyer, Kyle Evan. „Reducing the Cost of Chemistry in Reactive-Flow Simulations: Novel Mechanism Reduction Strategies and Acceleration via Graphics Processing Units“. Case Western Reserve University School of Graduate Studies / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=case1378393709.
Der volle Inhalt der Quelle
11
Jaime, Ruti. „How do I pronounce this word? : Strategies used among Swedish learners of English when pronouncing unfamiliar words“. Thesis, Karlstad University, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-4060.
Der volle Inhalt der QuelleAnnotation:
This study aimed to identify some of the strategies students used when pronouncing unfamiliar words. Questionnaires were handed out to 94 students in the 9th grade in a medium-sized Swedish town. In addition, two teachers and 13 students were interviewed. The results indicate that the students had acquired some basic knowledge about the English sound system from phonetic training in their past education. However, there seemed to be a tendency among the students to use the trial-and-error strategy to a larger extent than using tools such as phonetic transcription in order to figure out the pronunciation of a word. The results also show that the teachers did not teach planned lessons on pronunciation, but instead it was more common that they responded to errors made by students. In conclusion, the results show that the students' knowledge in pronunciation in general was limited. In addition, there seemed to be a connection between the way the students and the teachers approached pronunciation and the student's ability to solve pronunciation issues.
12
Brütsch, Benedikt Verfasser], Wolfgang [Akademischer Betreuer] Thomas, Nicolas [Akademischer Betreuer] Markey und Martin [Akademischer Betreuer] [Grohe. „Strategies in infinite games : structured reactive programs and transducers over infinite alphabets / Benedikt Brütsch ; Wolfgang Thomas, Nicolas Markey, Martin Grohe“. Aachen : Universitätsbibliothek der RWTH Aachen, 2018. http://d-nb.info/1221373315/34.
Der volle Inhalt der Quelle
13
Brütsch, Benedikt [Verfasser], Wolfgang Akademischer Betreuer] Thomas, Nicolas [Akademischer Betreuer] Markey und Martin [Akademischer Betreuer] [Grohe. „Strategies in infinite games : structured reactive programs and transducers over infinite alphabets / Benedikt Brütsch ; Wolfgang Thomas, Nicolas Markey, Martin Grohe“. Aachen : Universitätsbibliothek der RWTH Aachen, 2018. http://d-nb.info/1221373315/34.
Der volle Inhalt der Quelle
14
Bresolí, Obach Roger. „Novel strategies for singlet molecular oxygen O2(1Δg) generation and detection in cells“. Doctoral thesis, Universitat Ramon Llull, 2018. http://hdl.handle.net/10803/662972.
Der volle Inhalt der QuelleAnnotation:
En aquesta tesi s'han utilitzat diferents estratègies per obtenir control en la producció i detecció de diferents espècies reactives d'oxigen (ROS), especialment per a l'oxigen singlet (1O2).
En la primera part de la tesi, l'enfoc principal consisteix en entendre la generació de ROS i intentar potenciar-ne el seu efecte. En primer lloc, demostrem que la modificació de diferents fotosensibilitzadors afegint-hi un catió de trifenilfosfoni com a element diana produeix derivats amb una excel·lent activitat fotoantimicrobiana contra bacteris Gram-positius (S. aureus i E. faecalis). En segon lloc, descobrim una sèrie de nous aspectes de la reacció de “-phenyl quenching” per derivats de 9-fenilfenalenona. La fototoxicitat d’aquests derivats ja es troba esmentada en el llibre: “L'origen de les espècies” de C. Darwin. També es suggereix una via metabòlica mediada per la reacció BPQ en la biosíntesi dels pigments vegetals derivats de fluorones. A més, si el grup fenil és substituït per altres grups arils, s'observa diferencies en la reacció de BPQ. En tercer lloc, s’ha demostrat que diferents antraquinones d’origen natural indueixen fototoxicitat en biofilms de C. tropicalis a causa de la generació de O2•, tenint l’1O2 un rol menor. En quart lloc, es demostra el fàrmac antitumoral Doxorubicina produeix quantitats significants d’1O2, però es redueix la seva generació quan es complexa amb el ADN. En cinquè lloc, s’ha estudiat l’efecte d’adsorció o unió covalent d’un fotosensibilitzador a nanopartícules mesoporoses de sílice. A més a més, s’han derivatitzat per afegir-hi elements diana. Sisè i últim, s’ha estudiat les propietats fotoquímiques d’una nova diada que conté un bromo-bodipy com a fotosensibilitzador i trampa química de ROS (que desactiva la capacitat del bromo-bodipy de generar 1O2). Un cop oxidada la trampa química, la diada recupera la capacitat de generar 1O2 i causar dany cel·lular. S’observa diferents propietats foto-antitumorals d’aquesta diada en funció de l’estrès cel·lular o de la localització cel·lular.
En la segona part de la tesi, s'ha centrat en la detecció de ROS. En primer lloc, s’han dissenyat, sintetitzat i caracteritzat nanosondes fluorescents per la detecció d'1O2 en sistemes biològics. La nanovehiculització elimina algunes de les limitacions de les diferents sondes fluorescents d’1O2. En aquest sentit, diverses sondes tals com SOSG, ADPA o furil-vinil-naftooxazol s’han unit covalentment a nanopartícules utilitzant diferents cadenes espaiadores per tal d’optimitzar la seva reactivitat front 1O2. A diferència de quan es troben lliures en solució, les nanosondes són fàcilment internalitzades per cèl·lules eucariotes i procariotes i es minimitza la interacció amb proteïnes (com per exemple, l’albúmina de sèrum boví). Les diferents nanosondes responen a l’1O2 generat intracel·lular. Com a prova de concepte, també s’ha desenvolupat una nanosonda fluorescent per la detecció no selectiva de ROS, basada en 2’,7’-diclorodihidrofluoresceina. En segon lloc, s’ha caracteritzat la estructura i reactivitat de la sonda fluorescent: CellROX Deep Red. En tercer lloc, s’ha desenvolupat la primera sonda d’optoacústica per la detecció de ROS basada en l’oxidació de la tetrametilbenzidina. S’ha aconseguit detectar 1O2 produït per bacteris utilitzant tal sonda.
Finalment i com a prova de concepte, s’ha dissenyat un “self-reporter” nanofotosensibilitzador. El nanosistema és capaç de produir i detectar 1O2 simultàniament. Aquest nanodispositiu s'ha utilitzat amb èxit per la fotoinactivació de S. aureus, observant-se una correlació entre el canvi de fluorescència de la sonda i la mort bacteriana.En esta tesis se han utilizado distintas estrategias para obtener el control en la producción y detección de diferentes especies reactivas de oxígeno (ROS), especialmente para el oxígeno singlete (1O2). En la primera parte de la tesis, el enfoque principal consiste en entender la generación de ROS e intentar potenciar su efecto. En primer lugar, demostramos que la modificación de distintos fotosensibilizadores, añadiendo un catión de trifenilfosfonio como elemento diana, produce derivados con una excelente actividad fotoantimicrobiana contra bacterias Gram-positivas (S. aureus y E. faecalis). En segundo lugar, descubrimos una serie de nuevos aspectos de la reacción de "-phenyl quenching" por derivados de 9-fenilfenalenona. La fototoxicidad de estos derivados ya se encuentra mencionada en el libro: "el origen de las especies" de C. Darwin. También se sugiere una vía metabólica mediada por la reacción BPQ en la biosíntesis de los pigmentos vegetales derivados de fluorenonas. Además, si el grupo fenilo es sustituido por otros grupos arilos, se observan diferencias en la reacción de BPQ. En tercer lugar, se ha demostrado que distintas antraquinonas de origen natural inducen fototoxicidad en biofilms de C. tropicalis debido a la generación de O2•, teniendo el 1O2 un rol menor. En cuarto lugar, se demuestra que el fármaco antitumoral Doxorubicina produce cantidades significantes de 1O2, pero se reduce su generación cuando se compleja con el ADN. En quinto lugar, se ha estudiado el efecto de adsorción o unión covalente de un fotosensibilizador a nanopartículas mesoporosas de sílice. Además, se han derivatizado para añadir elementos diana. Sexto y último, se han estudiado las propiedades fotoquímicas de una nueva diada que contiene un bromo-bodipy como fotosensibilizador y trampa química de ROS (que desactiva la capacidad del bromo-bodipy para generar 1O2). Una vez oxidada la trampa química, la diada recupera la capacidad para generar 1O2 y causar daño celular. Se observan diferentes propiedades foto-antitumorales de esta diada en función del estrés celular o de la localización celular. La segunda parte de la tesis, se ha centrado en la detección de ROS. En primer lugar, se han diseñado, sintetizado y caracterizado nanosondas fluorescentes para la detección de 1O2 en sistemas biológicos. La nanovehiculización elimina algunas de las limitaciones de las distintas sondas fluorescentes de 1O2. En este sentido, varias sondas tales como SOSG, ADPA o furilo-vinilo-naftooxazol se han unido covalentemente a nanopartículas utilizando distintas cadenas espaciadoras para optimizar su reactividad frente 1O2. A diferencia de cuando se encuentran libres en solución, las nanosondas son fácilmente internalizadas por células eucariotas y procariotas y se minimiza la interacción con proteínas (como por ejemplo con la albúmina de suero bovino). Las distintas nanosondas responden al 1O2 generado intracelular. Como prueba de concepto, también se ha desarrollado una nanosonda fluorescente para la detección no selectiva de ROS, basada en 2',7'-diclorodihidrofluoresceina. En segundo lugar, se ha caracterizado la estructura y reactividad de la sonda fluorescente: CellROX Deep Red. En tercer lugar, se ha desarrollado la primera sonda de optoacústica para la detección de ROS basada en la oxidación de la tetrametilbenzidina. Se ha logrado detectar 1O2 producido por bacterias emprando tal sonda. Finalmente, y como prueba de concepto, se ha diseñado un "self-reporter" nanofotosensibilitzador. El nanosistema es capaz de producir y detectar 1O2 simultáneamente. Este nanodispositivo ha sido utilizado con éxito para la fotoinactivación de S. aureus, observándose una correlación entre el cambio de fluorescencia de la sonda y la muerte bacteriana.
In this thesis, different strategies have been used in order to gain control in reactive oxygen species (ROS) production and detection, especially for singlet oxygen (1O2). In the first part of the thesis, the main focus is towards understanding ROS generation and try to potentiate its effect. First, we demonstrate that modification of different photosensitisers with the triphenylphosphonium cation yields derivatives with an excellent photoantimicrobial activity against Gram‐positive bacteria (i.e., S. aureus and E. faecalis). Second, we uncover a number of new aspects of -phenyl quenching reaction in 9-phenylphenalenone scaffold, whose phototoxicity was already mentioned in Darwin’s Origin of Species. It is suggested an excited state-mediated metabolic pathway in the biosynthesis of fluorone plant pigments. Moreover, if phenyl moiety is substituted for other aryl groups, it is observed that the electrocyclic ring opening back to ground state ketones have lifetimes between miliseconds and picoseconds. Third, we demonstrate that the main photosensitizing mechanism, involved in the photo-induced C. tropicalis antibiofilm activity by natural anthraquinones, is via O2• production, whereas 1O2 participation seems of lesser importance. Fourth, we demonstrate that doxorubicin produces significant amounts of 1O2, however, this is largely suppressed when bound to DNA. Fifth, we studied the effect of PS adsorption or covalently bond onto the surface of mesoporous silica nanoparticles. Moreover, we further derivatitze them for attach targeting elements. Sixth and last, we studied the activation a new dyad comprising a bromo-bodipy, which acts as PS, plus a non-selective ROS chemical trap, which quenches the ability of bromo-bodipy to produce 1O2. For that aPS we observe a differential behaviour in function of the cellular stress or even in function of the organelle. In the second part of the thesis, focus has been shifted towards ROS detection. First, we designed, synthesized, and characterized biocompatible fluorescent nanoprobes for 1O2 detection in biological systems that circumvents many of the limitations of the different molecular 1O2 fluorescent probes. Under that purpose different 1O2 probes (Singlet Oxygen Sensor Green, anthracene dipropionic acid and furyl-vinyl-naphthoxazole) were covalently linked to nanoparticles core using different architectures to optimize their response to 1O2. In contrast to its molecular counterpart, the optimum nanoprobes are readily internalized by prokaryotic and eukaryotic cells and they do not interact with proteins (i.e. bovine serum albumin). Furthermore, the spectral characteristics do not change inside cells, and the probe responds to intracellular generated 1O2 with the corresponding change in fluorescence. As a proof of concept, a non-selective ROS fluorescent nanoprobe, based on diacetyl 2’,7’-dichlorodihydrofluorescein, has been synthetized and successfully used for detecting intracellular ROS. Second, we have performed the chemical characterization of the CellROX Deep Red, a new commercial non-selective ROS fluorescent probe, ascertained its putative chemical structure and evaluated its reactivity towards different reactive oxygen/nitrogen species and light in solution. Third, we developed the first ROS optoacoustic probe based on the oxidation of tetramethylbenzidine and successfully used for detecting 1O2 produced by bacteria. Finally, as proof of concept we have designed a self-reporter nanophotosensitizer. The nanosystem is capable to produce and detect the 1O2 generated simultaneously. It has been successfully used for S. aureus photoinactivation in which a correlation was observed between fluorescent change of the probe and bacterial cellular death.
15
Betke, Annika [Verfasser], und Guido [Akademischer Betreuer] Kickelbick. „A comparison of synthetic strategies for the synthesis of metal oxide nanoparticles : reactive milling and microjet reactor process / Annika Betke. Betreuer: Guido Kickelbick“. Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2014. http://d-nb.info/1059390477/34.
Der volle Inhalt der Quelle
16
Betke, Annika Verfasser], und Guido [Akademischer Betreuer] [Kickelbick. „A comparison of synthetic strategies for the synthesis of metal oxide nanoparticles : reactive milling and microjet reactor process / Annika Betke. Betreuer: Guido Kickelbick“. Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:291-scidok-59100.
Der volle Inhalt der Quelle
17
Kimmel, Shawn Christopher. „Considerations for and Implementations of Deliberative and Reactive Motion Planning Strategies for the Novel Actuated Rimless Spoke Wheel Robot IMPASS for the Two-Dimensional Sagittal Plane“. Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/32324.
Der volle Inhalt der QuelleAnnotation:
IMPASS is a novel spoke-wheel robot invented by researchers at the Robotics and Mechanisms Lab (RoMeLa) at Virginia Tech. The robot is driven by a rimless spoke wheel which can alter the length of any given spoke in the hub. This form of novel locomotion combines the efficiency of a wheeled robot and the mobility of a legged robot, arriving at a very practical mobility platform. A highly mobile robot such as IMPASS could prove very valuable in applications where the terrain is complex and dangerous, such as search and rescue, reconnaissance, or anti-terror response. A prototype has been constructed that effectively demonstrates the actuated spoke wheel concept using two wheels containing six spokes each.
Manually controlling the motion of two wheels and twelve spokes would be a daunting task for any operator. Due to this inherent complexity, automated motion control is a necessity for the IMPASS platform. The work presented here will discuss two different approaches to the motion planning problem for the two-dimensional sagittal plane. The first approach is deliberative in nature and depends on fairly accurate terrain sensing. The motion planning first decides on a set of contact points based on obstacle configurations and a Lagrangian interpolation of the terrain. A lower level motion planning component then executes the movements that guide the spoke ends to the contact points. The second motion planning approach is reactive in nature. Proprioceptive and tactile sensors are used to determine the robot's pose and immediate surroundings. These sensors directly affect the motion profile of the robot. The reactive approach follows much simpler logic, which theoretically will make it more robust.
Motion planning strategies were tested in simulation and on the IMPASS prototype. Both strategies proved to be well suited for different applications. The deliberative control was very successful in a structured environment, whereas the reactive control was able to cross a wider variety of terrain. The results from the testing also provided some insight into variables introduced by the hardware. Future improvements to the motion planning control include accounting for these variables in the hardware and eventually developing three-dimensional motion planning algorithms based on the lessons learned from the two-dimension case.Master of Science
18
Garcia, Guerrero Estefania [Verfasser], Hermann [Gutachter] Einsele und Alois [Gutachter] Palmetshofer. „Strategies to Obtain Tumor-Reactive Cells for Cancer Immunotherapy by Cell Sorting and Genetic Modifications of T Lymphocytes / Estefania Garcia Guerrero ; Gutachter: Hermann Einsele, Alois Palmetshofer“. Würzburg : Universität Würzburg, 2017. http://d-nb.info/1140871005/34.
Der volle Inhalt der Quelle
19
Wu, Marcio Jolhben. „Análise do efeito do investimento inicial no dilema do prisioneiro contínuo iterado simultâneo e alternado na presença e ausência de ruído em diferentes cenários de incerteza: contrapondo as estratégias RTS e LRS por meio da simulação bas“. Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/47/47132/tde-02032016-153429/.
Der volle Inhalt der QuelleAnnotation:
O dilema do prisioneiro é geralmente visto como o ponto de partida para entender o problema da cooperação. Em comparação com o dilema do prisioneiro discreto e iterado, poucos estudos existem sobre o dilema do prisioneiro contínuo e iterado. A maioria dos trabalhos que investigaram o dilema do prisioneiro contínuo e iterado concentrou-se no período de 1990 a 2000, não obtendo resultados conclusivos sobre a melhor estratégia a ser adotada neste tipo de jogo. Duas estratégias diferentes se destacam neste tipo de dilema. A primeira é a estratégia RTS (Raise-the-Stakes) de Roberts e Sherrat (1998) que testa o terreno antes de aumentar os investimentos na relação. A segunda deriva do modelo LRS (Linear Reactive Strategies) de Wahl e Nowak (1999a). Esta última estratégia estando em equilíbrio de Nash cooperativo apresenta três características: (i) generosidade, i.e., investir o máximo possível no início da relação de cooperação; (ii) otimismo, i.e., contar com o melhor cenário para as próximas rodadas, e (iii) intransigência. Esta pesquisa tem como objetivo principal contrapor as estratégias RTS e LRS num dilema do prisioneiro contínuo e iterado, na presença e ausência de ruído, com jogadas simultâneas e alternadas e para diferentes valores do parâmetro w (probabilidade de interagir novamente). Restringimos a nossa análise a um conjunto de seis estratégias: ALLC, ALLD, TFT, RTS, LRS e RTSM. O método utilizado foi o da simulação baseada em agente (ABM) no formato de torneios, semelhante ao de Axelrod (2006), Roberts & Sherratt (1998), Nowak & Sigmund (1992) e Nowak & Sigmund (1993). Utilizamos o software Netlogo e documentamos todo o processo da concepção e construção do modelo por meio da ferramenta TRACE (TRAnsparent and Comprehensive model Evaludation). Os resultados mostram que as estratégias mais cooperativas são mais favorecidas quando o jogo consiste em jogadas alternadas ao invés de simultâneas. A estratégia RTS teve melhor desempenho em jogos simultâneos para valores intermediários de w, na presença ou ausência de ruído. Por sua vez, a estratégia LRS teve melhor desempenho nos jogos simultâneos, na presença ou ausência de ruído, ou alternados e na presença de ruído, em ambos os casos para valores grandes de wThe prisoner\'s dilemma is generally seen as the starting point for understanding the problem of cooperation. In comparison with the discreet and iterated prisoner\'s dilemma, few studies exist on the continuous iterated prisoner\'s dilemma. Most of the works that have investigated the continuous iterated prisoner\'s dilemma has concentrated in the period from 1990 to 2000, not getting conclusive results on the best strategy to be adopted in this type of game. Two different strategies stand out in this kind of dilemma. The first is the RTS strategy (Raise-the-Stakes) of Roberts and Sherrat (1998) that tests the ground before increasing investment in the relationship. The second is the model deriva LRS (Linear Reactive Strategies) de Wahl and Nowak (1999a). This last strategy being in Nash equilibrium cooperative presents three characteristics: (i) generosity, i.e., investing as much as possible at the beginning of the cooperation relationship; (ii) optimism, i.e., rely on the best scenario for the next rounds, and (iii) intransigence. This research has as main goal to reconcile opposing RTS strategies and LRS in a continuous iterated prisoner\'s dilemma, in the presence and absence of noise, with simultaneous moves and alternate and for different values of the parameter w (probability of interacting again). We restrict our analysis to a set of six strategies: ALLC, ALLD, TFT, RTS, LRS and RTSM (halfway between RTS and LRS). The method used was the agent-based simulation (ABM) in tournament format, similar to that of Axelrod (2006), Roberts (1998), Sherratt & Nowak & Sigmund (1992) and Nowak & Sigmund (1993). We use the NetLogo software and document the whole process of design and construction of the tool model TRACE (TRAnsparent and Comprehensive model Evaludation). The results show that most strategies are more favoured unions when the game consists of alternating plays rather than simultaneous. The RTS strategy had better performance in simultaneous games for intermediate values of w, in the presence or absence of noise. In turn, the IRS strategy had better performance when simultaneous games, in the presence or absence of noise, or switched, and in the presence of noise, in both cases, for large values of w
20
Galloway, W. R. J. D. „Reaction and purification strategies in skeletal diversity construction“. Thesis, University of Cambridge, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.599287.
Der volle Inhalt der QuelleAnnotation:
The first project discussed in this report involves a diversity-oriented synthesis (DOS) approach starting from a structurally simple diazoacetate substrate. Overall, a library of 223 compounds based around 30 different core molecular skeletons was synthesized. The library was shown to span a comparatively large region of chemical space and phenotypic screening experiments identified a number of structurally novel compounds that displayed antibacterial activity against a pathogenic strain of MRSA. The second project discussed in this report involves studies towards the development of a novel solubility-control group for attached reagents, based on a triphenylene core, which would allow the facile removal of supported reagents and by-products from reaction mixtures. A triphenylene-supported triphenyphosphine derivative was synthesized, which preliminary studies suggested was functionally equivalent to triphenylphosphine in a Mitsunobu reaction. The generation of molecules based around a diverse range of molecular skeletons is key to maximising the functional (biological) diversity of a small molecule collection. Within this context medium rings constitute an interesting target skeleton; medium ring systems are present within numerous bioactive molecules yet there are few widely-applicable methods for their construction and thus they are often under-represented in small molecule libraries. Towards this end, the third project discussed in this report involves studies towards the synthesis of structurally novel benzo-fused medium lactone ring systems and the 12-membered benzo-fused lactone ring system present in the biologically active natural product lasiodiplodin. Methodology based around organocuprate oxidation was compared with more ‘traditional’ Sonogashira and Castro-Stephens approaches. In general, the synthesis of the desired ring systems could not be achieved, with none of these three approaches demonstrating broad synthetic utility.
21
Kelsey, Richard David. „C/D ring strategies in an organoiron approach to hippeastrine“. Thesis, University of East Anglia, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327391.
Der volle Inhalt der Quelle
22
Bourdon, Gérard. „Strategie reactive d'accostage entre robots mobiles autonomes en milieu contraint. Approche par techniques floues“. Paris 6, 1996. http://www.theses.fr/1996PA066491.
Der volle Inhalt der QuelleAnnotation:
Ce travail de these traite de l'elaboration et de la mise en place experimentale d'une methode d'accostage entre robots mobiles autonomes en milieu inconnu et contraint. L'objectif est donc de definir une strategie reactive permettant a un robot suiveur de s'asservir sur un robot cible quelque soit leur configuration relative initiale. Ce travail a pour but de s'inserer ulterieurement dans une tache de collaboration entre bras manipulateurs mobiles. La conception du robot romain (robot mobile autonome instrumente), realise au cours de cette these est egalement abordee. Ce robot rapide tire son originalite de conception dans son architecture materielle decentralisee, organisee autour d'un bus local de communication. Cette plate-forme performante et flexible utilise comme suiveur a permis de valider experimentalement la strategie developpee. Les approches proposees font appel aux techniques floues dont les proprietes description et d'approximation sont utilisees pour la resolution d'un probleme robotique complexe. Il s'agit en effet d'apporter une solution d'une part, a la gestion d'evenements asynchrones, et d'autre part, de definir une methode d'accostage, le tout devant mener a une strategie reactive de prepositionnement de mobiles en vue d'une cooperation en mouvement. Une methode d'evitement reflexe est developpee, centree sur le principe d'une modelisation qualitative de la contrainte locale et de la mobilite du systeme. De cette modelisation en ligne, a partir d'une base de connaissance, est deduit le mouvement du suiveur. La manoeuvre d'accostage, envisagee tout d'abord sans contrainte d'environnement, resulte de l'etablissement d'une loi de guidage par prediction du point de rendez-vous et de la definition d'un champ de forces floues permettant de reconstituer la configuration spatiale de la cible. Une methode de fusion est proposee, permettant l'accostage d'une cible manoeuvrante dans un espace contraint.
23
Van, Winkle Carolyn. „Forensic DNA Extraction Strategies for PCR Analysis“. Thesis, University of North Texas, 1998. https://digital.library.unt.edu/ark:/67531/metadc278269/.
Der volle Inhalt der QuelleAnnotation:
There is a transition nationwide on the analysis of forensic evidentiary stains containing biological material from traditional serology to Polymerase Chain Reaction (PCR) methodologies. The increased sensitivity of PCR, the limited number of alleles at each locus, and the necessity of producing unambiguous data for entry into the FBI's Combined DNA Index System make this study of extraction procedures of utmost importance. A "single tube" extraction procedure for blood stains collected onto FTA™ paper and a modified differential nonorganic extraction method from spermatozoa containing
mixed stains were analyzed and compared. The extraction success was evaluated by amplification and typing of the amplified fragment length polymorphism, D1S80. These modifications of the nonorganic method utilized gave an improved separation of the spermatozoa-containing mixed stains.
24
Schultz, Christopher R. „An Autonomous Underwater Vehicle for Validating Internal Actuator Control Strategies“. Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/33190.
Der volle Inhalt der QuelleAnnotation:
There are benefits to the use of internal actuators for rotational maneuvers of small-scale underwater vehicles. Internal actuators are protected from the outside environment by the external pressure hull and will not disturb the surrounding environment during inspection tasks. Additionally, internal actuators do not rely on the relative fluid motion to exert control moments, therefore they are useful at low speed and in hover. This paper describes the design, fabrication and testing of one such autonomously controlled, internally actuated underwater vehicle.
The Internally Actuated, Modular Bodied, Untethered Submersible (IAMBUS) can be used to validate non-linear control strategies using internal actuators. Vehicle attitude control is provided by three orthogonally mounted reaction wheels. The housing is a spherical glass pressure vessel, which contains all of the components, such as actuators, ballast system, power supply, on-board computer and inertial sensor. Since the housing is spherically symmetric, the hydrodynamics of IAMBUS are uncoupled (e.g. a roll maneuver does not impact pitch or yaw). This hull shape enables IAMBUS to be used as a spacecraft attitude dynamics and control simulator with full rotational freedom.
Master of Science
25
Winogron, H. William (Henry William) Carleton University Dissertation Psychology. „Reaction times and speed-accuracy tradeoff strategies in head-injured and normal children“. Ottawa, 1986.
Den vollen Inhalt der Quelle finden
26
Waterfall, Christy Marie. „Strategies for the detection of single nucleotide polymorphisms using the polymerase chain reaction“. Thesis, University of Bath, 2002. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269677.
Der volle Inhalt der Quelle
27
Monyoncho, Evans Angwenyi. „In-Situ and Computational Studies of Ethanol Electrooxidation Reaction: Rational Catalyst Design Strategies“. Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/35940.
Der volle Inhalt der QuelleAnnotation:
Fuel cells represent a promising technology for clean power generation because they convert chemical energy (fuel) into electrical energy with high efficiency and low-to-none emission of pollutants. Direct ethanol fuel cells (DEFCs) have several advantages compared to the most studied hydrogen and methanol fuel cells. First and foremost, ethanol is a non-toxic liquid, which lowers the investment of handling facilities because the current infrastructure for gasoline can be largely used. Second, ethanol can be conveniently produced from biomass, hence is carbon neutral which mitigates increasing atmospheric CO2. Last but not least, if completely oxidized to CO2, ethanol has a higher energy density than methanol since it can deliver 12 electrons per molecule. The almost exclusive oxidation to acetic acid overshadows the attractiveness of DEFCs considerably, as the energy density is divided by 3. The standard potential of acetic acid formation indicates that a reaction path including acetic acid, leads to inevitable potential losses of about 0.4 V (difference between ideal potential for CO2 and acetic acid "production").
The development of alkaline DEFCs had also been hampered by the lack of stable and efficient anion exchange membranes. Fortunately, this challenge has been well tackled in recent years,8,9 making the development of alkaline fuel cells (AFCs) which are of particular technological interest due to their simple designs and ability to operate at low temperatures (25-100 °C). In alkaline conditions, the kinetic of both the cathodic oxygen reduction and the anodic ethanol oxidation is facilitated. Furthermore, the expensive Pt catalyst can be replaced by the lower-cost and more active transition metals such as Pd.
The main objectives of this project are: i) to provide detailed fundamental understanding of ethanol oxidation reaction on transition metal surfaces in alkaline media, ii) to propose the best rational catalyst design strategies to cleave the C–C bond during ethanol electrooxidation. To achieve these goals two methodologies are used, i.e., in-situ identification of ethanol electrooxidation products using polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) and mechanistic investigation using computational studies in the framework of density functional theory (DFT). The PM-IRRAS technique was advanced in this project to the level of distinguishing electrooxidation products at the surface of the nanoparticles (electrode) and in the bulk-phase of the electrolyte. This new PM-IRRAS utility makes it possible to detect molecules such as CO2 which desorbs from the catalyst surface as soon as they are formed. The DFT insights in this project, provides an explanation as to why it is difficult to break the C–C bond in ethanol and is used for screening the top candidate metals for further studies.
28
Falklind, Jerkérus Susanna. „Vibrio cholerae O139 : identification, characterization and vaccine strategies /“. Stockholm, 2003. http://diss.kib.ki.se/2003/91-7349-696-0/.
Der volle Inhalt der Quelle
29
Grothe, Julia, Florian Wissner, Benjamin Schumm, Giovanni Mondin und Stefan Kaskel. „Precursor strategies for metallic nano- and micropatterns using soft lithography“. Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-189005.
Der volle Inhalt der QuelleAnnotation:
Soft lithographic methods describe a set of printing methods which are widely used for the preparation of structured surfaces. Structured surfaces are essential components in the field of (opto-)electronic devices such as organic light emitting diodes, photovoltaics or organic field effect transistors. In recent years, crucial progress has been achieved in the development of patterned metal coatings for these applications. This review focusses on new strategies for soft lithographical printing of metal structures emphasizing the subtle interplay of printing techniques, metal precursor chemistry, and surface functionalization strategiesDieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich
30
Al-Hindi, Mahmoud. „Operating strategies for heat exchangers and networks of heat exchangers subject to fouling and variable inlet conditions“. Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321935.
Der volle Inhalt der Quelle
31
Grothe, Julia, Florian Wissner, Benjamin Schumm, Giovanni Mondin und Stefan Kaskel. „Precursor strategies for metallic nano- and micropatterns using soft lithography: Review“. Royal Society of Chemistry, 2015. https://tud.qucosa.de/id/qucosa%3A29056.
Der volle Inhalt der QuelleAnnotation:
Soft lithographic methods describe a set of printing methods which are widely used for the preparation of structured surfaces. Structured surfaces are essential components in the field of (opto-)electronic devices such as organic light emitting diodes, photovoltaics or organic field effect transistors. In recent years, crucial progress has been achieved in the development of patterned metal coatings for these applications. This review focusses on new strategies for soft lithographical printing of metal structures emphasizing the subtle interplay of printing techniques, metal precursor chemistry, and surface functionalization strategies.Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
32
Patil, Dadasaheb V. „Intramolecular cyclization strategies for synthesizing medium-ring polycycles and the total synthesis of natural products“. Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/50118.
Der volle Inhalt der QuelleAnnotation:
Carbo- and heterocyclic compounds are of great interest to chemists. Intramolecular cyclization strategies of donor-acceptor (D-A) cyclopropanes and alkylidene malonate monoamides have excellent potential for synthesis as they offer easy access to structurally-diverse compounds. The work described in this thesis accesses the scope of the In(OTf)3-catalyzed cyclization reaction of cyclopropanes and alkylidene malonate monoamides. In(OTf)3-catalyzed reactions of alkenyl and heteroaryl cyclopropyl ketones were examined in the synthesis of functionalized cyclohexenone-based derivatives (Chapter 2). Subsequent efforts to utilize a tandem cyclopropane ring-opening/Friedel-Crafts alkylation sequence of methyl 1-(1H-indolecarbonyl)-1-cyclopropanecarboxylates to prepare functionalized hydropyrido[1,2-a]indole-6(7H)-ones is discussed in Chapter 3. The extension of this tandem protocol towards the total synthesis of (±)-deethyleburnamonine is the subject of Chapter 6. Intramolecular Friedel-Crafts alkylation of N-indolyl alkylidene malonate monoamides was also examined. An In(OTf)3-catalyzed cyclization of substituted methyl 2-(1H-indole-1-carbonyl) acrylates afforded a series of 1H-pyrrolo[1,2-a]indole-3(2H)-ones (Chapter 4), whereas substrates with the indole 2-position blocked provided access to substituted 4H-pyrrolo[3,2,1-ij]quinolin-4-ones (Chapter 5).
33
Maiser, Benjamin [Verfasser], und J. [Akademischer Betreuer] Hubbuch. „Development of optimized reaction- and purification strategies for polymer-modified proteins / Benjamin Maiser. Betreuer: J. Hubbuch“. Karlsruhe : KIT-Bibliothek, 2013. http://d-nb.info/1050767373/34.
Der volle Inhalt der Quelle
34
Tchernook, Ivan. „Strategies for Computational Investigation of Reaction Mechanisms in Organic and Polymer Chemistry Using Static Quantum Mechanics“. Doctoral thesis, Universitätsbibliothek Chemnitz, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-198756.
Der volle Inhalt der QuelleAnnotation:
This thesis presents computational studies of problems in the organic and polymer chemistry. The state-of-the art quantum chemical methods are used to gain further insight into the origin and the nature of the reactions in three different organic and polymer systems. The research questions are conceptually approached by identifying the key aspects. Then an appropriate strategy for the quantum chemical modeling is developed.
In the scope of the polymer chemistry, the novel synthesis technique of nanostructured materials, the so-called twin polymerization, is investigated. Using three model systems of increasing complexity the influence of the anion (trifluoroacetate) in the reaction system is investigated. The effect of the solvent polarity as well as the effect of the entropic contributions are also considered.
The rearrangement reaction of the volatile cyanotritylcarbenes is another topic. These carbenes readily rearrange to ethene main products, however also small amount of the unexpected heptafulvenes is formed. This unprecedented heptafulvene formation is modeled in detail and the energetics is systematically evaluated to identify most reasonable rearrangement pathways of the probable multiple alternative routes. Computational investigation of other tritylcarbenes with varying spectator substituents results in sophisticated data base for experimental investigations.
At last, some controversial observations in experimental studies concerning the kinetics of the electrophilic alkylation of the barbiturate anion are studied. To interpret the kinetic measurements, different alkylation pathways are analyzed with respect to their energetics. Further, the influence of microsolvation is demonstrated.
35
Capes, Amy. „Synthetic strategies for potential trypanocides“. Thesis, University of Dundee, 2011. https://discovery.dundee.ac.uk/en/studentTheses/ea009d64-46cd-4b42-9ed8-2225e94d963d.
Der volle Inhalt der QuelleAnnotation:
Human African trypanosomiasis (sleeping sickness) is a devastating disease which is endemic in parts of sub-Saharan Africa. It is caused by the protozoan parasite T. brucei, which are transmitted by the bite of infected tsetse flies. Although the disease is fatal if left untreated, there is a lack of safe, effective and affordable drugs available; therefore new drugs are urgently needed. The aim of the work presented in this thesis is to develop novel trypanocidal compounds. It is divided into two parts to reflect the two distinct strategies employed to achieve this aim. The first part focuses on the inhibition of glycophosphoinositol (GPI) anchor synthesis by inhibiting the Zn2+-dependent enzyme, GlcNAc-PI de-N-acetylase. Trypanosomes have a variable surface glycoprotein (VSG) coat, which allows them to evade the human immune system. The GPI anchor attaches the VSG to the cell membrane; therefore inhibiting GPI synthesis should expose the parasite to the immune system. Initially, large substrate analogues were synthesized. These showed weak inhibition of the enzyme. Zinc-binding fragments were screened, and small molecule inhibitors based on salicylhydroxamic acid were then synthesized. These compounds showed modest inhibition, but the excellent ligand efficiency of salicylhydroxamic acid indicates this may be a promising starting point for further inhibitors. The second part details the P2 strategy. The P2 transporter is a nucleoside transporter unique to T. brucei, which concentrates adenosine. The transporter also binds and selectively concentrates compounds that contain benzamidine and diaminotriazine P2 motifs, which can enhance the potency and selectivity of these compounds. The sleeping sickness drugs melarsoprol and pentamidine contain P2 motifs. Compounds comprising a P2 targeting motif, a linker and a trypanocidal moiety were synthesized. Initially, a diaminotriazine P2 motif was attached to a trypanocidal tetrahydroquinoline (THQ) protein farnesyl transferase (PFT) inhibitor, with limited success. The P2 strategy was also applied to a non-selective, trypanocidal, quinol moiety. The quinol moiety was attached to diaminotriazine and benzamidine P2 motifs, and an increase in selectivity for T. brucei over MRC5 cells was observed.
36
Potgieter, Roelof Daniel. „Goal orientation, the growth mindset and coping strategies for success and failure in competitive sport“. Diss., University of Pretoria, 2011. http://hdl.handle.net/2263/30330.
Der volle Inhalt der QuelleAnnotation:
In today’s sport careers there is no room for error. This is why athletes should be “on top of their game” every time they compete. It is very important for athletes to keep their emotions under control, because emotions can sometimes determine success or failure. But more important is how the athlete reacts to success and failure. Therefore, in this study the aim was to establish an athlete’s reaction to success and failure. An athlete should have the ability or strategy to handle success and failure. According to this statement, it underlines the importance of the current study. The fact that there are limited resources in this field accentuates the need for this study. Each athlete experiences and reacts to success or failure differently. An athlete can use success or failure as a facilitator or as a debilitator. If an athlete sees success or failure as a facilitator, he or she will use success or failure as a method to enhance his or her performance. But if an athlete sees success and failure as a debilitator, it means that the athlete does not have the ability or skills to use success or failure to his or her advantage. It seems that elite athletes may have the skills or ability to use success and failure as a facilitator and not as a debilitator owing to the fact that in the elite arena there is no place for errors. In this study, the researcher examines how elite and beginner athlete’s handle success and failure and what their reaction is towards success and failure. Each athlete has a unique way to develop his or her talents. Athletes who believe that they are born with limited talent or ability and cannot improve this talent by more practice or more effort can be classified as having a static mindset. When athletes believe that they can improve their talent or ability, they could be seen as athletes with a growth mindset. This study made use of a combination of convenient and random sampling. Each athlete had to comply with the criterium to be part of the study. The criterium stipulated that each athlete should be an active participant in sport either at school-, provincial-, national- or international level. To determine what goal orientation each athlete had, they were asked to fill out the task- and ego orientation in sport questionnaire. To determine what their reactions to success and failure were, athletes completed an assessment of success and failure questionnaire that was self-developed by the present researcher Roelie Potgieter and his study leader professor Ben Steyn. The self-theory questionnaire that was completed by the athletes determined whether an athlete was in the fixed or growth mindset. Using the results determined through the questionnaires that were completed by the athletes, correlations could be made to motivate the study. Task orientation and the growth mindset is more predominant than ego orientation and the fixed mindset. Athletes in general react more constructively towards success and failure. A strong correlation was found between task orientation and positive reaction to success and failure. Partial correlation between ego orientation and positive reaction to success was found. Positive relations were discovered between task orientation and the growth mindset, as well as ego orientation and the fixed mindset. AFRIKAANS : In vandag se sportloopbane is daar geen ruimte vir foute nie. Vir hierdie rede moet ‘n atleet ten alle tye op sy of haar beste wees. Dit is baie belangrik vir ‘n atleet om sy emosies in toom te hou, want somtyds kan die atleet se emosies bepaal of hy of sy sukses of mislukking gaan ervaar. Daarom is die doel van die studie om die reaksie van atlete op sukses en mislukking te bepaal. Die feit dat daar ‘n beperkte hoeveelheid navorsing oor die tema van die studie is beklemtoon weereens die belangrikheid van die studie. Elke atleet ervaar en reageer verskillend op sukses en mislukking. ‘n Atleet kan sukses of mislukking gebruik as ‘n fasiliteerder of as ‘n debiliteerder. As ‘n atleet sukses of mislukking sien as ‘n fasiliteerder, sal die atleet sukses of mislukking gebruik as ‘n metode om sy of haar prestasie/s te verbeter. Indien ‘n atleet sukses en mislukking sien as ‘n debiliteerder, beteken dit dat die atleet nie die vermoë of vaardighede het om sukses of mislukking te gebruik tot sy of haar voordeel nie. Dit wil voorkom dat elite atlete die vermoë of vaardighede het om sukses en mislukking te gebruik tot hulle voordeel, as gevolg van die feit dat daar geen plek vir foute tydens die kompetisie is nie. In die studie probeer die navorser bepaal hoe elite- en beginner atlete sukses en mislukking hanteer en wat hulle reaksie op sukses en mislukking is. Elke atleet het ‘n unieke manier om sy of haar talente te ontwikkel. Atlete wat glo dat hulle gebore is met ‘n talent of vermoë en kan nie die talent verbeter met oefening of ‘n groter poging kan geklassifiseer word as statiese instelling. Indien die atleet glo dat hulle, hulle talent kan verbeter, kan dit gesien word as ‘n groeiende instelling. Hierdie studie maak van die gemaklike sowel as die ewekamsige steekproefmetode gebruik. Elke deelnemer moes voldoen aan sekere kriterium om deel te wees van die studie. Die studie se kriteria het beklemtoon dat elke atleet aktief betrokke in ‘n sekere sportsoort moet wees, mag dit wees op skool-, provinsiale-, nasionale- of internasionale vlak. Om te bepaal watter tipe doeloriëntering elke atleet is was hulle gevra om die taak en ego oriëntasie vraelys in te vul. Deur die verwysing kan bepaal word wat hulle reaksie is tot sukses en mislukking, was daar van die atlete verwag om die vrae oor sukses en mislukking te voltooi. Die selfteorie vraelys wat deur die atlete voltooi is, het bepaal of die atlleet ‘n statiese of groeinde instelling het. Deur gebruik te maak van die resultate van die vraelyste wat voltooi is deur die atlete kon daar korrelasies gemaak word. Taakoriëntasie en die groeiende instelling is meer dominant as die ego oriëntasie en die statiese instelling. Atlete in die algemeen reageer meer konstruktief teenoor sukses en mislukking. ‘n Sterk korrelasie was gevind deur taakoriëntasie en positiewe reaksie tot sukses en mislukking. Gedeeltelike korrelasie kon gemaak word tussen ego oriëntasie en positiewe reaksie tot sukses. ‘n Positiewe korrelasie kon gemaak word tussen taakoriëntasie en groeiende instelling, asook ego oriëntasie en statiese instelling.Dissertation (MA)--University of Pretoria, 2011.
Biokinetics, Sport and Leisure Sciences
unrestricted
37
Meng, Zhiyong. „Self-assembly and chemo-ligation strategies for polymeric multi-responsive microgels“. Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29743.
Der volle Inhalt der QuelleAnnotation:
Thesis (Ph.D)--Chemistry and Biochemistry, Georgia Institute of Technology, 2009.Committee Chair: Lyon, Louis; Committee Member: Breedveld, Victor; Committee Member: Bunz, Uwe; Committee Member: Collard, David; Committee Member: Srinivasarao, Mohan. Part of the SMARTech Electronic Thesis and Dissertation Collection.
38
Racine, Kathryn Claire. „Evaluation of cocoa (Theobroma cacao) bean processing strategies to enhance alpha-glucosidase inhibitory activity of dietary cocoa“. Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/90295.
Der volle Inhalt der QuelleAnnotation:
Cocoa beans (Theobroma cacao) are a highly concentrated source of dietary flavanols- bioactive compounds associated with the health protective properties of cocoa. Cocoa beans undergo processing steps, such as fermentation, roasting, winnowing, grinding, pressing, etc., to produce a final product with specific desirable sensory attributes. It is well established that these processing steps, specifically fermentation and roasting, result in dramatic degradation of cocoa's native flavanols, but it is possible that these processing steps may generate compounds with novel activities, potentially preserving or enhancing bioactivity. Raw unfermented cocoa beans were processed by way of a partial factorial approach to produce cocoa powders from the same batch of raw beans using various combinations of fermentation [unfermented, cool fermented (maximum 46°C), hot fermented (maximum 60°C))] and roasting [unroasted, cool roasted (120°C), hot roasted (170°C)]. To simulate cocoa fermentation in a highly controlled environment, a pilot-scale fermentation model system was employed to eliminate many external unknowns and ensure that the differences between our cocoa powders were due to our various treatments, rather than unknown factors occurring during fermentation and roasting. Low and high molecular weight fractions (8-10 kDa cutoff) were produced from cocoa powder extracts (CPE) of each treatment to quantify Maillard reaction products (MRP). A HILIC-UPLC MS/MS method was developed to more efficiently and sensitively quantify cocoa flavanols with high degrees of polymerization (DP) produced during processing. Overall, cocoa processing significantly (p<0.05) decreased the total phenolic and total flavanol concentrations of CPEs. Hot roasting had the greatest impact on native flavanol degradation yet produced CPEs with the highest mean degree of polymerization (mDP). All CPEs dose-dependently inhibited α-glucosidase enzyme activity, with cool fermented/cool roasted cocoa powder exhibiting the best inhibition (IC50 of 62.2 µg/mL). Increasing flavanol mDP was correlated with decreasing IC50 values, suggesting that the complex flavanols produced during processing enhance cocoa's bioactivity (or their production is associated with other products that enhance bioactivity). Alternatively, high molecular weight CPE fractions were correlated with increasing IC50 values, suggesting that MRPs interfere with enzyme inhibition or are associated with other products (polyphenols, macronutrients, etc.) that interfere with enzyme inhibition. Overall, the data presented within this work indicate that the components of processed cocoa powders are promising inhibitors of α-glucosidase, despite a significant reduction in native flavanol composition induced by processing, and moreover that fermentation and roasting conditions can positively influence the bioactivity of cocoa despite losses of native flavanols.Master of Science in Life Sciences
According to the Centers for Disease Control and Prevention, obesity-related chronic conditions such as cardiovascular disease and type 2 diabetes mellitus (T2D) are the leading cause of preventable and/or premature death, with 51% of the American population predicted to be obese by 2030. Cocoa (Theobroma cacao) is a highly concentrated source of polyphenols, and these compounds have been shown to interact with and inhibit digestive enzymes responsible for carbohydrate breakdown. By inhibiting the activity of these digestive enzymes, it is possible to slow down carbohydrate absorption after a meal and ultimately reduce large spikes in blood glucose levels, being a promising strategy in the prevention and maintenance of T2D. Cocoa beans undergo processing steps to produce a final product, such as cocoa powder, and it is known that these processing steps reduce the levels of beneficial polyphenols. Yet, how this processing-induced degradation effects the health protective activities of cocoa is still widely unknown and is the focus of this work. Through highly controlled cocoa bean processing, cocoa powders of different processing conditions were produced and used to assess how various processing parameters impacted digestive enzyme activity. Overall, processing steps did reduce levels of native polyphenols. However, these losses did not demonstrate a reduction in enzyme inhibition and certain processing conditions actually enhanced digestive enzyme inhibition. This research shows promise for the potential use of processed cocoa powder as an effective strategy in the prevention and maintenance of T2D and further work must be done to understand the mechanisms behind this relationship.
39
Denman, Paula Kerri. „Modelling strategies for the healing of burn wounds“. Queensland University of Technology, 2007. http://eprints.qut.edu.au/16433/.
Der volle Inhalt der QuelleAnnotation:
Epidermal wound healing requires the coordinated involvement of complex cellular and biochemical processes. In the case of epidermal wounds associated with burns, the healing process may be less than optimal and may take a significant amount of time, possibly resulting in infection and scarring. An innovative method to assist in the repair of the epidermis (the outer layer of skin) is to use an aerosolised apparatus. This method involves taking skin cells from an area of the patient's undamaged skin, culturing the cells in a laboratory, encouraging them to rapidly proliferate, then harvesting and separating the cells from each other. The cells are then sprayed onto the wound surface. We investigate this novel treatment strategy for the healing of epidermal wounds, such as burns. In particular, we model the application of viable cell colonies to the exposed surface of the wound with the intent of identifying key factors that govern the healing process. Details of the evolution of the colony structure are explored in this two-dimensional model of the wound site, including the effect of varying the initial population cluster size and the initial distribution of cell types with different proliferative capacities. During injury, holoclones (which are thought to be stem cells) have a large proliferative capacity while paraclones (which are thought to be transient amplifying cells) have a more limited proliferative capacity. The model predicts the coverage over time for cells that are initially sprayed onto a wound. A detailed analysis of the underlying mathematical models yields novel mathematical results as well as insight into phenomena of healing processes under investigation. Two one-dimensional systems that are simplifications of the full model are investigated. These models are significant extensions of Fisher's equation and incorporate the mixed clonal population of quiescent and active cells. In the first model, an active cell type migrates and proliferates into the wound and undergoes a transition to a quiescent cell type that neither migrates nor proliferates. The analysis yields the identification of the key parameter constraints on the speed of the healing front of the cells on this model and hence the rate of healing of epidermal wounds. Approximations for the maximum cell densities are also obtained, including conditions for a less than optimal final state. The second model involves two active cell types with different proliferative capacity and a quiescent cell type. This model exhibits two distinct behaviours: either both cell types coexist or one of them dies out as the wound healing progresses leaving the other cell type to fill the wound space. Conditions for coexistence are explored.
40
Gu, Tonghan. „Experimental and computational study of mass transport in novel emulsion systems : strategies for reaction engineering and microparticle preparation“. Thesis, Massachusetts Institute of Technology, 2018. https://hdl.handle.net/1721.1/121891.
Der volle Inhalt der QuelleAnnotation:
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Chemical Engineering, 2018Cataloged from PDF version of thesis.
Includes bibliographical references (pages 167-171).
Emulsions are complex fluids with interesting physiochemical properties, which have been widely used in health and personal care, food, coating, and manufacturing, etc.. Rather than considering emulsions as passive materials, they can also be used as active blocks for material preparation and chemical synthesis. This thesis presents a study of mass transport phenomena in two specific types of emulsion systems: microfluidic emulsions and concentrated food emulsions. For microfluidic emulsion systems, the first mass transport phenomenon studied is the exchange of chemicals between microfluidic droplets, which are 10-100 pm in size, and nanodroplets, which are dispersed as a nano- or mini-emulsion. Chemically, thermally, or electrically induced coalescence and micelle activity control the mass exchange between micro- and nano-droplets, leading to applications in reaction engineering and microparticle preparation.
Microdroplets function as micro-reactors that receive chemical from nanodroplets with both the addition rate and dosage well-controlled. The microdroplets could also function as micro-reservoirs that steadily supply chemical to the nanodroplets. For microparticle preparation, microdroplets function as templates to be solidified by reagents carried by the nanodroplets. The second mass transport phenomenon in microfluidic emulsions is the evaporation of droplet solvents or the exchange of solvents between droplets and the continuous phase, which leads to solid precipitation. In particular, this thesis focuses on the formation of drug crystalline particles. A novel solvent/anti-solvent exchange method with a hydrogel binder was developed to prepare highly monodisperse microparticles of either hydrophilic or hydrophobic drugs from microdroplet templates. In addition, we also improved a previously developed spherical crystallization method based on droplet solvent evaporation.
We used the same hydrogel but as a temporary immobilization media to prevent droplet coalescence and to expand the applicable solvent library of this method for industrial applications. For concentrated food emulsions, the mass transport phenomenon studied is the fast removal of the continuous phase and the microencapsulation of lipids into microparticles. With the spray drying technology, "powdered oil" containing up to 55 wt% (dry mass basis) of liquid oil was successfully prepared from concentrated milk protein stabilized emulsions. We discovered that pre-evaporation of raw milk not only offers energy cost savings, but also reduces fat loss. With additional carbohydrates, the surface extractable fat was reduced and powder wettability was improved. This product will serve as the main ingredient of an instant powder ready-to-use therapeutic food for treating child malnutrition in India.
by Tonghan Gu.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Chemical Engineering
41
Wynn, Andrew Joseph. „The evaluation of chemical reaction dynamics within swine-raising facility implications to odor evolution and assessment of abatement strategies /“. Master's thesis, Mississippi State : Mississippi State University, 2003. http://library.msstate.edu/etd/show.asp?etd=etd-04022003-144706.
Der volle Inhalt der Quelle
42
Spinato, Cinzia. „Development of chemical strategies to prepare multifunctional carbon nanotubes for anticancer therapy“. Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAF037.
Der volle Inhalt der QuelleAnnotation:
L’application de nanotubes de carbone (CNTs) dans le domaine biomédical a été largement explorée grâce à leur propriétés physico-chimiques et à leur biocompatibilité. Par la fonctionnalisation extérieur et/ou intérieur des CNTs c’est possible de préparer des nouveaux conjugués avec différentes propriétés et applications. On a exploré la modification des nanotubes par voie covalente pour leur utilisation comme vecteurs de biomolécules pour achever la thérapie anticancéreuse. Pendant ma thèse, j’ai travaillé sur trois projets: l’application de différentes approches pour la conversion des groupes acides carboxyliques de MWCNTs oxydés en amines, dans le but de préparer des conjugués capables de complexer du siRNA (petits ARN interférents). Dans un second projet, j’ai développé des conjugués à base de nanotubes de carbone couplés avec un fragment d’anticorps thérapeutique via une liaison clivable afin d’en étudier le potentiel antitumoral. Dans le dernier projet, on a achevé la fonctionnalisation de CNTs remplis avec des molécules radioactivables par cycloaddition de nitrene et ensuite conjugué un anticorps de ciblage tumoral. Le but été d’utiliser les nanotubes comme vecteurs pour la délivrance de radioactivité à l'intérieur des cellules tumorales ciblées par l’anticorps. On a aussi conduit des investigations biologique, afin d’évaluer la toxicité et l’efficace de ce conjuguéThe application of carbon nanotubes (CNTs) in the biomedical field has been widely explored thanks to their physico-chemical properties and their biocompatibility. By the external and/or internal functionalization of CNTs it is possible to prepare novel conjugates tailoring different properties and applications. We have investigated the covalent derivatization of CNTs by different chemical strategies to achieve suitable carriers for anticancer therapy. In one project, we have explored the conversion of the carboxylic groups of oxidized CNTs into amino groups, and the ability of these conjugates to complex genetic material, for gene delivery. In another project, CNTs have been functionalized with linkers bearing a cleavable disulfide bond, and further conjugated to a therapeutic nanobody for controlled intracellular drug release. Finally, we have investigated the reactivity of close-ended CNTs filled with radioactivable material toward Bingel and nitrene cycloadditions and the conjugation of a targeting antibody, for the target delivery of radioactivity. By several characterization techniques we have proved that the antibody is covalently grafted to the CNT-carrier and it still possesses its targeting ability. Investigations on the biological profile of these conjugates (cytotoxicity, targeting, uptake, biodistribution) have been also carried out
43
Trejos, Alejandro. „Palladium-Catalysed Couplings in Organic Synthesis : Exploring Catalyst-Presenting Strategies and Medicinal Chemistry Applications“. Doctoral thesis, Uppsala universitet, Avdelningen för organisk farmaceutisk kemi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-173068.
Der volle Inhalt der QuelleAnnotation:
Palladium-catalysed coupling reactions have been embraced by synthetic chemists as one of the preferred means for smooth formation of new carbon-carbon bonds: a truly ubiquitous methodology of synthesizing complex molecules. This thesis describes the study of a series of palladium(0)-catalysed C2-arylations of a 1-cyclopentenyl ether, equipped with a chiral (S)-N-methyl-pyrrolidine auxiliary. The investigated olefin was demonstrated to undergo Si-face insertion, providing (R)-configuration of the arylated C2-carbon. In addition, the mild and novel palladium(II)-catalysed dominoHeck/Suzuki β,α-diarylation-reduction of a dimethylaminoethyl-substituted chelating vinyl ether was developed using arylboronic acids as arylating agents in combination with 1,4-benzoquinone (BQ). Further, highly regioselective palladium(II)-catalysed α-and β-monoarylation of the chelating vinyl ether was achieved using either a bidentate ligand or by employing ligand-less conditions. These studies demonstrate that the choice of ligands has a profound effect on the reaction outcome, as productive β,α-diarylation could only be obtained by suppressing the competing β-hydride elimination using BQ as the stabilising ligand and terminal reoxidant. The pivotal role of BQ in the reaction was studied using computer-aided density functional theory calculations. The calculations highlight the crucial role of BQ as a Pd(II)-ligand. In addition of serving as an oxidant of palladium, the calculations support the view that the coordination of BQ to the Pd(II)-centre in the key σ-alkyl complex leads to a low-energy pathway, aided by a strong η2 Pd-BQ donation-back-donation interaction. Furthermore, an investigation of the scope and limitations of novel stereoselective and BQ-mediated palladium(II)-catalysed domino Heck/Suzuki β,α-diarylation reactions, involving metal coordinating cyclic methylamino vinyl ethers and a number of electronically diverse arylboronic acids, conducted. In addition, a set of 4-quinolone-3-carboxylic acids, structurally related to elvitegravir and bearing different substituents on the condensed benzene ring, was designed and synthesized as potential HIV-1 integrase inhibitors. Finally, in an effort to identify a new class of HIV-1 protease inhibitors, four different stereopure β-hydroxy γ-lactam-containing inhibitors were synthesized, biologically evaluated, and co-crystallized with the enzyme.The time 12:05 for the public defense mentioned in the thesis is incorrect. It will take place at 09:15, 2012-06-08.
44
Nicolai, Anja [Verfasser], Klaus [Akademischer Betreuer] Brieß, Klaus [Gutachter] Brieß und Martin [Gutachter] Tajmar. „Magnetic field mitigation strategies towards a magnetically clean reaction wheel / Anja Nicolai ; Gutachter: Klaus Brieß, Martin Tajmar ; Betreuer: Klaus Brieß“. Berlin : Technische Universität Berlin, 2021. http://d-nb.info/124030949X/34.
Der volle Inhalt der Quelle
45
Neal, Orin J. „Responses to the audio broadcasts of predator vocalizations by eight sympatric primates in Suriname, South America“. [Kent, Ohio] : Kent State University, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=kent1245291915.
Der volle Inhalt der QuelleAnnotation:
Thesis (M.A.)--Kent State University, 2009.Title from PDF t.p. (viewed Jan. 26, 2010). Advisor: Marilyn Norconk. Keywords: predation; anti-predator strategies; alarm calls. Includes bibliographical references (p. 111-120).
46
Shcherbakova, Elena G. „Implementation of High Throughput Screening Strategies in Optical Sensing for Pharmaceutical Engineering“. Bowling Green State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1510758614142002.
Der volle Inhalt der Quelle
47
Gali, Meghanath. „Synthesis of Small Molecule Inhibitors of Janus Kinase 2, Phosphodiesterase IV, GABAA and NMDA receptors: Investigation of Mcmurry, Mannich and Chemoenzymatic Strategies“. Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3110.
Der volle Inhalt der QuelleAnnotation:
Stilbenoids possess a wide range of biological properties such as, anticancer, antiplatelet aggregation, antiestrogenic, antibacterial, antifungal and antiatherogenic, etc. Owing to these therapeutic values, a great deal of attention attracted in the synthesis of derivatives of stilbenes. During the course of the study, G6 a novel stilbenoid was discovered, through high throughput screening, to be a potent inhibitor of mutated JAK2-V617F. The mutated JAK2 variant has been implicated in various myeloproliferative disorders (MPDs) including polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF) has been targeted by therapeutics. Chapter 2 describes the synthesis of analogs of the stilbenoid G6 and N-substituted stilbenes bisoxazines by utilizing Mcmurry reaction and Mannich condensation methods. The main emphasis of this work is to develop novel stilbenoids as inhibitors of JAK2-V617F mutated Jak2 enzyme in Human erythroleukemia cells (HEL) since this mutation is discovered in the majority of patients with myeloproliferative disorders (MPDs). Using Mcmurry reaction, five novel trans-hydroxystilbenes have been synthesized from carbonyl compounds. Subsequently using Mannich coupling with five secondary amines and five primary amines, 25 novel stilbenoids and 9 novel N-substituted stilbene bisoxazines have been synthesized. In HEL cell assay, 8 stilbenoid analogues have been identified as potent inhibitors of Jak2 enzyme.
Chapter 3 describes the modification of ketamine structurally for the synthesis of novel analogues to study for their agonist activity at GABAA receptors and antagonist activity at NMDA receptors. Ligand gated ion channels like GABAA and NMDA receptors are membrane-embedded proteins at synaptic cleft which controls intercommunication among neurons and plays an important role in motor control activity, learning. GABAA receptors are responsible for inhibitory action potentials while NMDA receptors are responsible for excitory action potentials. Ketamine, known as dissociative anesthetic, produces profound analgesia at low doses to a unique cardiovascular stimulation and a cataleptic state at higher doses with dose dependent side effects like vivid dreams, disruptions of cognitive functions. The main emphasis of this work is the synthesis of novel analogues of ketamine by transforming carbonyl group in ketamine to imine functionality with small to bulkier groups and to identify an analogue of ketamine which is highly potent in its activity at the both GABAA and NMDA receptors and improved clinical actions. Studies of analogues activity against GABAA subtypes α6Β2δ, α1Β2γ2 receptors and NMDA subtypes NR1/2A, NR1/2B, NR1/2D receptors have been described.
Chapter 4 describes the formal synthesis of (±)-Rolipram and the chemoenzymatic synthesis of -aryl--lactone, a Rolipram analogue. The key steps, Pd catalyzed arylation of diethylmalonate and the efficient use of selective acylation of 1, 3-diol entails the formal synthesis of (±)-Rolipram. The regioselective deacylation of Β-aryl-1, 4-diacetate by lipase Pseudomonas Sepacia entails the formation of Β-aryl-γ-lactone. The efficient use of various methods including halogen exchange, Heck arylation of diethylmaleate and lactonization for the synthesis of Β-aryl-γ-lactone have been discussed. The present work provides an efficient and general route to γ-lactones.
48
CONNAN, PIERRE YVES. „Etude, a la lumiere des temps de reaction, des strategies lexicales et des analyses phonetico-acoustiques en reconnaissance lexicale auditive, a partir de parole naturelle“. Université Marc Bloch (Strasbourg) (1971-2008), 1998. http://www.theses.fr/1998STR20014.
Der volle Inhalt der QuelleAnnotation:
Si l'experience quotidienne de la communication orale atteste de l'efficacite du mecanisme general de perception et de comprehension des enonces, cela ne doit pas pour autant nous faire oublier qu'il s'agit la d'un mecanisme d'une extreme complexite. La nature meme de la parole continue, veritable flux sonore distribue temporellement mais souvent lacunaire, variable et difficilement segmentable en unites discretes, semble impossible a concilier avec notre apparente facilite a comprendre le langage parle. Cette complexite est egalement due aux nombreuses etapes (acces, selection et integration) propres au traitement lexical et aux multiples relations qui existent entre les representations mentales : les dimensions phonologiques, morphologiques et semantiques peuvent interagir a des niveaux et a des moments divers parmi ces processus. Cette etude, qui repose sur une tache de decision lexicale ainsi que sur des mesures comportementales (temps de reaction), devrait permettre une meilleure connaissance de l'organisation des strategies mise en oeuvre pour la reconnaissance des mots. Un autre interet de ce travail consiste alors a chercher si la reconnaissance de la parole est facilitee (paradigme d'amorcage) quand un mot ou un non-mot 'amorce' et 'cible' partagent la meme sequence initiale, dont le statut, soit phonologique, soit morphemique, pourrait modifier les conditions d'acces au lexique mental. Les resultats montrent l'absence d'effet de l'amorcage phonologique et le statut specifique de la premiere syllabe 'morphemique', le prefixe, qui facilite la decision lexicale. Les donnees issues de plusieurs populations d'auditeurs francais non entraines, classes selon le sexe et l'age, sont analysees en relation constante avec des modeles interactifs de reconnaissance lexicale, telle la theorie de la cohorte qui donne la priorite a l'analyse acoustico-phonetique (bottom-up) et une importance particuliere au debut des mots et aux informations 'top-down'If daily practice of oral communication shows how performant is the general processing of perception and comprehension of spoken utterances, we can't forget that spoken word recognition is an extremely complex phenomenon. On-going speech is naturally 'directional' in time but often incomplete, variable and very difficult to segment into discrete units. All these arguments seem incompatible with the intrinsic facility of understanding spoken language. This complexity is also due to the numerous steps (access, selection and integration) that constitute the lexical processing, and to the multiple relationships that exist within mental representations: phonological, morphological and semantic dimensions can interact at different levels and times in these processes. This study, based on a lexical decision task and on comportemental measurements (reaction times), should enable a better understanding of the organization of word recognition strategies. A major question addressed here, is to find out if auditory word recognition is facilitated (priming paradigm) when a word or a non-word prime and target share the same initial sequence, whose status, whether phonological or morphemic, may change access conditions to the mental lexicon. The results show a lack of phonological priming effect and the specific status of the initial morphemic syllable (prefix) as a factor that facilitates lexical decision. The data from large groups of untrained french listeners, classified by sex and age, are discussed in relation to interactive lexical recognition models such as the cohort theory, that have shown the priority of acoustic-phonetic analysis of the incoming speech signal ('bottom-up' information), the importance of word onsets and the role of 'top- down' information and processes
49
Olusegun-Osoba, Elizabeth Oluwakemi. „Strategies towards the synthesis of 4-(3-methyl-but-1-enyl)-3,5,3',4'-tetrahydroxystilbene (arachidin-1) and resveratrol analogues“. Thesis, University of Hertfordshire, 2015. http://hdl.handle.net/2299/17118.
Der volle Inhalt der QuelleAnnotation:
Stilbene phytoalexins such as resveratrol, 1, and the arachidins, including arachidin-1,2, are naturally synthesised by peanut (Arachis hypogaea) plants. The peanut phytoalexins are polyphenolic compounds consisting of a stilbene backbone, with a number of derivatives also possessing a prenyl moiety. These distinctive phytoalexins have gained attention, as they exhibit various biological activities, for instance arachidin-1, 2, has been reported to be more potent than resveratrol, 1, in the inhibition of lipopolysaccharide-induced expression of cyclooxygenase-2 (COX-2) and COX-2 mRNA, in vitro at doses that were low in cytotoxicity. Additionally the various arachidins have recently been shown to exhibit their anti-inflammatory properties, through the inhibition of a number of inflammatory mediator pathways. In this work, various routes into the synthesis of arachidin-1, 2, are described, via use of the Horner-Wadsworth-Emmons (HWE) reaction. Three different methodologies were explored, the first approach involving silyl ether (TIPS or TBDMS) protected benzaldehydes, proved unsuccessful due to cleavage of the silyl ether protecting groups, in basic and/or acidic conditions. This led to an alternative approach, whereby formation of the stilbene backbone proceeded via the regioselective demethylation of an acetal in the presence of sodium metal, subsequent electrophilic substitution using iodomethane and finally acetal hydrolysis of the acetal, gave the isolated aldehyde in moderate yield (52 %). Coupling of the aldehyde with the substituted benzylphosphonate, via the HWE reaction gave the desired trans-stilbene in good yield (86 %), however incorporation of the prenyl side chain proved to be challenging via the Wohl-Ziegler bromination. Further adaptation of the aforementioned route, whereby alkylation using diethyl iodomethylphosphonate, enabled the incorporation of the prenyl moiety and the subsequent construction of the trans-stilbene backbone, gave the 4-(3-methyl-but-1- enyl)-3,5,3',4'-tetramethoxystilbene, 3, albeit in poor yield (47 %). The final step involving demethylation using BBr3 gave arachidin-1, 2, also in poor yield (30 %), nevertheless this approach has been proved to be a successful route for the total synthesis of arachidin-1, 2, however optimised studies are required in order to obtain the desired compound in quantitative yields. Synthetic analogues of resveratrol, 1, are also known for their biological activities, including anti-inflammatory and chemopreventative properties. Recently, the anti-proliferative activity of a number of stilbenesulfonamides, against the National Cancer Institute's 60 (NCI-60) human tumour cell line has been reported. Furthermore, the anti-inflammatory effects of novel heterocyclic methylsulfone and sulfonamide analogues, via inhibition of the COX-2 protein have also been published, however both synthetic routes described require a total of six or seven steps, from the sulfanilamide and are limited to the synthesis of primary sulphonamides (SO2NH2). In this work, an efficient three step synthesis has been designed and successfully implemented, proceeding via chlorosulfonation of diethyl benzylphosphonate, to form the sulfonyl chloride intermediate. Aminolysis of the sulfonyl chloride intermediate was then performed, using a range of primary, secondary and cyclic alkyl amines, as well as aromatic amines; including ammonia, dimethylamine, morpholine and diphenylamine. Finally, formation of the stilbene backbone with various substituted aldehydes, via the HWE reaction offered a short, versatile and alternative route to the synthesis of novel primary, secondary and tertiary trans-stilbene benzenesulfonamides and heterocyclic analogues, in yields of 42 - 100 %. The activity of a selection of the synthesised stilbene benzenesulfonamides was evaluated against the human lung adenocarcinoma epithelial cell line (A549). Amongst the compounds tested, analysis of the data showed that the novel analogue, 4, was found to be the most potent compound, with a GI50 of 0.1 μM. Comparison with the previously published data found analogue, 4, to be approximately 500-fold more potent than the lead compound resveratrol, 1, (GI50 = 51.64 μM) and approximately twice as potent than 5-fluorouracil (GI50 = 0.189μM), a chemotherapy drug used to treat various forms of cancer 8. Overall, these results demonstrate that the total synthesis of trans-arachidin-1, 2, can be achieved via a five step methodology. A versatile route to the synthesis of novel stilbene benzenesulfonamides has also been successfully achieved, amongst the compounds synthesised one appears to show promising anticancer activity, and warrants further investigation (i.e. in vitro studies using other cancer cell lines, and the synthesis of additional compounds using analogue, 4, as a lead compound).
50
Magrabi, Ammar Mohammed. „Building responsive capability for disaster managemen. An empirical study of the Saudi Civil Defence Authority“. Thesis, University of Bradford, 2011. http://hdl.handle.net/10454/5446.
Der volle Inhalt der QuelleAnnotation:
Disasters are always local in their impact, and therefore approaches towards their
alleviation need to be designed and implemented based on this certainty. Since the
1960s there has been a constant evolution in the common understanding of
international disaster management. Various measures and structures were created to
plan for emergency relief and the management of a disastrous event. Despite
international efforts which aimed to reduce the impact of natural and anthropogenic
hazards on humankind, very little progress was made. Loss of life, property,
infrastructure and economic livelihoods are on the increase without any indication of
improvement. Developmental activities can in most instances be blamed for the high
level of disaster risk present in communities. On the other hand, very little has been
done in the international arena (through a multi-disciplinary approach) to ensure a
developmental focus on disaster risk. This study investigates the current state of
disaster management practices in the Kingdom of Saudi Arabia (KSA) by
benchmarking its activities against established frameworks applied in the developed
world for disaster management.
The aim of this thesis was primarily to provide a comprehensive framework for
disaster risk management in KSA. Such a framework will serve as a guideline for all
spheres of government on a strategic level in order to implement disaster risk
management.
Conclusions to the research demonstrate the importance of linking government
policy and practice on disaster risk management across different stakeholders
involved in managing disaster risk. This study proposed an integrated model for
disaster management by introducing the dual paradigm of disaster management
(proactive mindset and reactive mindset).
In a nutshell, this thesis aimed to develop a comprehensive multi-disciplinary
disaster risk management framework that would be tailor-made for the strategic
management arena in Saudi Arabia¿s Ministry of Interior (Directorate of Civil
Defence). The research provides the reader with a background study on the
international development of the concept of disaster risk management and its
components. It focuses on disaster risk management within the Saudi Arabian
context. Four international disaster risk management frameworks are analytically
compared and aligned with international best practices. Subsequently, the proposed
Framework for Disaster in Saudi Arabia is analysed.