Dissertations / Theses on the topic 'Mechanism'
To see the other types of publications on this topic, follow the link: Mechanism.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Mechanism.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Lezra, Esther Margaret. "Looking for monsters : mechanism of history, mechanisms of power /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2005. http://wwwlib.umi.com/cr/ucsd/fullcit?p3170235.
Full text
2
Ostrý, Josef. "Naklápěcí a zdvihový mechanismus skladovacího zásobníku." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231225.
Full textAbstract:
The aim of this master thesis is to design a structural arrangement of lifting and tilting mechanism storage tower SSI Logimat, including the design of the drive. The introduction included a description of selected vertical storage systems of different companies and then compared them. Another section includes the design lift and tilt mechanism, calculation and design their drives and the subsequent description of their components. At the end of the master thesis is attached the drawings of the proposed mechanisms.
3
Faiman, Jiří. "Tříválcový zážehový motor s excentrickým klikovým mechanismem pro osobní vozidla." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-231763.
Full textAbstract:
The first part of this thesis deals with the examination of the eccentricity of the crank mechanism for individual variables kinematics and dynamics of crank mechanism, analyticaly computed in Matlab. Then it compares the different possibilities of balancing moments of inertia forces and propose a specific design chosen for the value of eccentricity. In the second part is designed a model of crankshaft mechanism based on the investigated parameters. These parameters were carried out by structural analysis in Ansys.
4
Cestaro, Fernando Antonio Bassetti. "Machiavellian mechanism." reponame:Repositório Institucional da UFSC, 2012. http://repositorio.ufsc.br/handle/123456789/103422.
Full textAbstract:
Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Comunicação e Expressão, Programa de Pós-Graduação em Letras/Inglês e Literatura Correspondente, Florianópolis, 2012Made available in DSpace on 2013-07-16T04:34:20Z (GMT). No. of bitstreams: 0
O objetivo desta pesquisa é analisar a performance de Laurence Olivier como Ricardo, Duque de Gloucester, posteriormente Rei Ricardo III, no filme Richard III de 1955 sob a ótica do momento histórico contemporâneo da performance cinematográfica do ator britânico. E por momento histórico contemporâneo refiro-me à dicotômica disputa pelo poder entre os Estados Unidos da América (EUA) e a União das Repúblicas Socialistas Soviéticas (URSS) na Guerra Fria como uma imagem que se alinha com a apresentação fílmica dos momentos de definição da Guerra das Rosas. Neste sentido, eu objetivo esclarecer quais afirmações políticas-ambição, ações soturnas, derrota da tirania-Olivier pode fazer com sua performance do ambicioso vilão de Shakespeare. Portanto, em minha análise, eu foco no Maquiavelismo-a abordagem estereotípica e a interpretação distorcida das orientações de Nicolau Maquiavel apresentadas em seu livro O Príncipe-como uma noção política que tende a ver a política como um campo de batalha em que homens devem empregar quaisquer meios necessários para obter seus fins ambiciosos. Considerando que as performances teatral e fílmica de Olivier não se originam em um vácuo, eu discuto brevemente quatro performances icônicas-de Richard Burbage, David Garrick, Edmund Kean e Henry Irving-que podem ser vistas como influentes para as versões de Olivier do ambicioso vilão de Shakespeare. Também, quando eu discuto a performance fílmica de Olivier, eu alinho as noções do Cinema de Narrativa Clássica de David Bordwell e de Jane Stadler-como uma base para a adaptação cinematográfica do ator britânico-com as noções e visões de Anthony Davies sobre o filme de 1955. Por isso, ao alinhar o Maquiavelismo presente nas ações do Ricardo de Olivier com o momento histórico contemporâneo de sua performance cinematográfica, a presente análise demonstra que Olivier escolhe a mídia certa e o momento certo para trazer o infame personagem de Shakespeare à tela do cinema, ilustrando como a arte pode imitar a vida. Finalmente, eu defendo que a noção estereotípica de Maquiavel adotada por Shakespeare para construir seu personagem vil e seguida pelas performances de Burbage, Garrick, Kean e Irving auxilia na criação das versões teatral e cinematográfica de Olivier de Ricardo como um homem maquiavélico buscando poder político supremo.
Abstract : The aim of this research is to analyze Laurence Olivier's performance of Richard, Duke of Gloucester, later King Richard III, in the film Richard III from 1955 in the light of the contemporaneous historical moment of the British actor's cinematographic performance. And by contemporaneous historical moment I mean the dichotomist power dispute between the United States of America (USA) and the Union of Soviet Socialist Republics (USSR) in the Cold War as an image that aligns with the filmic presentation of the defining moments of the Wars of the Roses. In this sense, I aim to clarify what political statements-ambition, sullen actions, defeat of tyranny-Olivier can be seen to make with his performance of Shakespeare's ambitious villain. Therefore, in my analysis, I focus on the Machiavellianism-the stereotyped approach and the distorted interpretation of Niccolò Machiavelli's orientations presented in his book The Prince-as a political notion that tends to see politics as a battlefield in which men should employ whatever means necessary to obtain their ambitious ends. Regarding Olivier's theatrical and filmic performances do not originate in a vacuum, I briefly discuss four iconic performances-Richard Burbage's, David Garrick's, Edmund Kean's, and Henry Irving's-that can be seen to have influenced Olivier's renditions of Shakespeare's ambitious villain. Also, when I discuss Olivier's filmic performance, I align David Bordwell's and Jane Stadler's notions of Classical Narration Cinema-as a basis for the British actor's cinematographic adaptation-with Anthony Davies' notions and views on the 1955 film. Hence, by aligning the Machiavellianism present in Olivier's Richard's actions to the contemporaneous historical moment of his cinematographic performance, the present analysis demonstrates that Olivier chooses the right medium and the right moment to bring Shakespeare's villainous character to the silver screen, illustrating how art can imitate life. Ultimately, I argue that Machiavelli's stereotyped notion adopted by Shakespeare to construct his villainous character and followed by Burbage's, Garrick's, Kean's, and Irving's performances assist in the creation of Olivier's theatrical and cinematographic renditions of Richard as a Machiavellian man searching for ultimate political power.
5
Oosting, Kenneth W. "Simulation of control strategies for a two degree-of-freedom lightweight flexible robotic arm." Thesis, Georgia Institute of Technology, 1987. http://hdl.handle.net/1853/18230.
Full text
6
Alberts, Thomas Edward. "Augmenting the control of a flexible manipulator with passive mechanical damping." Diss., Georgia Institute of Technology, 1986. http://hdl.handle.net/1853/19442.
Full text
7
Szklarzewski, Veronica. "A mechanism for testing the torsional mechanics of origami-inspired hinges." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/98760.
Full textAbstract:
Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015.Cataloged from PDF version of thesis.
Includes bibliographical references (page 29).
Folding 2-dimensional sheets into static and dynamic 3-dimensional structures has the potential to improve rate, cost, and flexibility in manufacturing. In order to explore origami-inspired design, a better understanding of the mechanics of the fold is needed. This is to create better mathematical models and design for particular stiffness and fatigue specifications. The purpose of this study is to create a desktop machine that enables the measurement of the torsional stiffness of folded hinges over a wide angular range and a large number of cycles. This machine was then used to test 100 and 140 lb papers with 4 and 14 scores for the crease. Each paper was tested for 10 cycles and stiffness calculated. It was shown that 40 lb papers have higher reaction forces than the 100 lb papers. Stiffness measurements were inconclusive due to possible bending in addition to the hinging. For the 200 cycle around a 2 g decrease can be seen from I cycle to 200 cycles.
by Veronica Szklarzewski.
S.B.
8
Kim, Hyun Jung. "Oxidation mechanism of riboflavin destruction and antioxidant mechanism of tocotrienols." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1184681773.
Full text
9
Phelps, Stephen George. "Evolutionary Mechanism Design." Thesis, University of Liverpool, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.490710.
Full textAbstract:
The advent of large-scale distributed systems poses unique engineering challenges. In open systems such as the internet it is not possible to prescribe the behaviour of all of the components of the system in advance. Rather, we attempt to design infrastructure, such as network protocols, in such a way that the overall system is robust despite the fact that numerous arbitrary, non-certified, third-party components can connect to our system. Economists have long understood this issue, since it is analogous to the design of the rules governing auctions and other marketplaces, in which we attempt to achieve sociallydesirable outcomes despite the impossibility of prescribing the exact behaviour of the market participants, who may attempt to subvert the market for their own personal gain. This field is known as 'mechanism design': the science of designing rules of a game to achieve a specific outcome, even though each participant may be self-interested. Although it originated in economics, mechanism design has become an important foundation of multi-agent systems (MAS) research. In many scenarios mechanism design and auction theory yield clear-cut results; however, there are many situations in which the underlying assumptions of the theory are violated due to the messiness of the real-world. In this thesis I introduce an evolutionary methodology for mechanism design, which is able to incorporate arbitrary design objectives and domain assumptions, and I validate the methodology using empirical techniques.
10
Möller, Björn. "Modular mechatronic mechanism /." Stockholm, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-372.
Full text
11
Postl, Peter. "Applied mechanism design." Thesis, University College London (University of London), 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.405859.
Full text
12
Rodrigues, Nischal Joseph. "Pragmatic organicistic mechanism." abstract, 2008. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3307580.
Full text
13
Allred, Timothy Melvin. "Compliant Mechanism Suspensions." BYU ScholarsArchive, 2006. https://scholarsarchive.byu.edu/etd/434.
Full textAbstract:
This thesis has explored the use of compliant mechanisms in vehicle suspension systems, specifically where a compliant mechanism acts as part of the wheel locating mechanism and as the energy storage element. A compliant mechanism has the potential of reducing part count, joints, and manufacturing and assembly costs of a suspension system. Fatigue failure has been found to be a limiting design constraint which competes with space and weight constraints. Controlling wheel motion in response to control forces has also been shown to be an important functional requirement for a compliant suspension system. Vehicle applications that are best suited for the use of compliant suspension systems are those that are low weight, have low energy storage requirements, and do not require precise vehicle handling characteristics. New compliant suspension concepts have been explored that support the wheel in 3-dimensions to minimize undesired wheel motions. These new concepts demonstrate increased stiffness and decreased stress due to control forces. Of these concepts, the compliant A-Arm proves to be the most promising candidate for future development. It has added advantages of lower space requirements, lower number of extra joints and rigid links, and simpler design for manufacture and assembly. The stiffness, stress, and kinematic characteristics of the compliant A-Arm configuration have been explored. This configuration has a non-linear force-deflection curve that is facilitated by the stress-stiffening effects of large deflections. A closed-form linear stiffness solution and a pseudo-rigid-body model has also been developed to aid in the initial design of the compliant A-Arm in a suspension system.
14
Akhtar, Muhammad Asif. "Biochar Gasification Mechanism." Thesis, Curtin University, 2020. http://hdl.handle.net/20.500.11937/80395.
Full textAbstract:
Gasification-based technologies are at the core of many low emission technologies for the utilisation of low-rank fuels including biomass. This study focuses on the fundamental understanding of the kinetic compensation effects during the gasification of biochar with different gasifying agents. The kinetic compensation effects are examined together with structural properties of char to provide further insights into the char gasification mechanisms. The findings will contribute to the development of green bioenergy technologies.
15
Mlčoch, Pavel. "Čtyřválcový zážehový motor s excentrickým klikovým mechanismem pro osobní vozidla." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-232114.
Full textAbstract:
This Diploma Thesis is aimed at exploring the potential of offset crankshaft mechanism for four cylinder inline petrol engine in terms of reducing the frictional losses of the piston group. Thesis deals with the influence of eccentricity on kinematics, dynamics and balance of the crank train. Furthermore, specific crankshaft balancing is elaborated and applied on 3D CAD model of the crankshaft. Calculation of fatigue safety factor using the advanced LSA method that takes into consideration the effect of forced torsional vibration and utilizes outputs from the FEA software (ANSYS APDL) is performed as well. Thesis also includes design of two options of rubber torsion damper mounted on the engine belt pulley and the follow-up choosing of the more advisable one.
16
Mali, Girish Suresh. "Novel Escapement Mechanism using a Compliant Mechanism and a Piezoelectric Actuator." Digital WPI, 2007. https://digitalcommons.wpi.edu/etd-theses/1110.
Full textAbstract:
"Escapement mechanisms hold back a stream of parts driven either by mechanical or pneumatic means for a length of time and release a single part as required to an assembly station. They are used in most automatic multi-component assembly equipment. They occupy a significant design space and have dynamic characteristics of their own. This research aimed to develop a novel high speed mechanism for parts escapement that occupies less design space and contributes less to the dynamic activity of the structure. Several conceptual mechanisms were generated and evaluated. A compliant mechanism that amplifies the very small displacement of a piezo actuator was selected for detailed design. A proof of concept prototype was fabricated and tested. A piezo stack was used to bend a thin, spring steel, compliant beam. Its deflection was further amplified by attaching a comparatively rigid beam extension at the end of the compliant section. The mechanism escapes parts at 16 Hz using constrained layer damping on the beam to reduce vibrations. The concept is feasible to use on production machinery and provides advantages in terms of higher operating speeds and compactness. The concept could also be used where there is a requirement of high speed gating."
17
Zhong, Bo. "Mechanism-based Inhibitors for Copper Amine Oxidases: Synthesis, Mechanism, and Enzymology." Cleveland, Ohio : Case Western Reserve University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1259013895.
Full textAbstract:
Thesis(Ph.D.)--Case Western Reserve University, 2010Title from PDF (viewed on 2009-12-30) Department of Chemistry Includes abstract Includes bibliographical references and appendices Available online via the OhioLINK ETD Center
18
Hurník, Štěpán. "Otočný sloupový jeřáb plnícího vozu koksárenské baterie." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-229962.
Full textAbstract:
This master´s thesis deals with a proposed design of the derrick of the filling car of a coke-oven battery, which is used for working with unit loads, repairing and maintenance of the filling car and cleaning of the battery risers. In the first part a solution concept was chosen. For this concept a main steel structure was designed, which was controlled in stress analysis by the FEM program I-DEAS NX 11. Further, the main parts of the lifting and travelling mechanism were calculated using specified parameters. In the conclusion of this thesis the results summary of specified targets is stated. Assembly drawing is in the annex of this thesis.
19
Jensen, Brian D. "Identification of Macro- and Micro-Compliant Mechanism Configurations Resulting in Bistable Behavior." BYU ScholarsArchive, 2003. https://scholarsarchive.byu.edu/etd/83.
Full textAbstract:
The purpose of this research is to identify the configurations of several mechanism classes which result in bistable behavior. Bistable mechanisms have use in many applications, such as switches, clasps, closures, hinges, and so on. A powerful method for the design of such mechanisms would allow the realization of working designs much more easily than has been possible in the past. A method for the design of bistable mechanisms is especially needed for micro-electro-mechanical systems (MEMS) because fabrication and material constraints often prevent the use of simple, well-known bistable mechanism configurations. In addition, this knowledge allows designers to take advantage of the many benefits of compliant echanisms, especially their ability to store and release energy in their moving segments. Therefore, an analysis of a variety of mechanism classes has been performed to determine the configurations of compliant segments or rigid-body springs in a mechanism which result in bistable behavior. The analysis revealed a relationship between the placement of compliant segments and the stability characteristics of the mechanism which allows either analysis or synthesis of bistable mechanisms to be performed very easily. Using this knowledge, a method of type synthesis for bistable mechanisms has been developed which allows bistable mechanisms to be easily synthesized. Several design examples have been presented which demonstrate the method. The theory has also been applied to the design of several bistable micromechanisms. In the process of searching for usable designs for micro-bistable mechanisms, a mechanism class was defined, known as "Young" mechanisms, which represent a feasible and useful way of achieving micro-mechanism motion similar to that of any four-bar mechanism. Based on this class, several bistable micro-mechanisms were designed and fabricated. Testing demonstrated the ability of the mechanisms to snap between the two stable states. In addition, the mechanisms showed a high degree of repeatability in their stable positions.
20
Bartušek, Filip. "Posouzení traverzy mostového magnetového jeřábu 15t." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-241868.
Full textAbstract:
The diploma thesis deals with some parts of bridge magnet crane with 15 tons of nominal lifting capacity. This crane is designed for operation in the steel mill for handling billets using magnets suspended on the traverse. This work is focused on design of hoisting and traverse mechanism of crane trolley, selection of individual components on the basis of relevant standards and calculations. Next part of this thesis is investigation magnet traverse in terms of its strength according to standard ČSN EN 13001.
21
Jaffit, Danielle. "Mechanisms for embedding sustainability into organisational strategic decision-making: technology as an enabling mechanism." Master's thesis, University of Cape Town, 2016. http://hdl.handle.net/11427/23751.
Full textAbstract:
There is a growing need for businesses to shift toward a more sustainable strategic focus if they are to positively impact the societies within which they operate and remain viable businesses in the future. This is becoming increasingly acknowledged amongst South African organisations, however the challenge they face is in refocusing their strategic goals to be sustainably oriented. In order to tackle this challenge many organisations internationally and locally are starting to utilise information technology based tools and technological platforms as a mechanism for embedding sustainability into their business – tracking their impact and linking sustainability goals to their performance management structures using dashboards to visually represent this data. The intention of this research has been to explore the drivers of this organisational shift towards sustainability, internally and externally, the changes that are being implemented (the content of these strategic changes) and the processes organisations are implementing to become more sustainable. The specific focus is on the tools and technology they are utilising to enable this shift towards sustainability. This research takes the form of a qualitative cross case analysis of six organisations and utilises Pettigrew's framework for strategic change that looks at three parts of a change process: the context, content and process, to attempt to answer the question: How do technology platforms, and the ability for organisations to gather, monitor and manage organisational data relating to sustainability indicators result in more sustainable strategic decision-making within South African organisations? The results of this research demonstrate the link between quantifying activities and deeper integration of sustainable activities within the organisation. The role technology plays, based on the analysis of six South African companies, is frequently dependent on the driver of the quantifying activity and the degree to which the data has an effect on the broader business targets.
22
Nokleby, Scott Brian. "Optimization-based mechanism synthesis." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ40563.pdf.
Full text
23
Husain, A. H. "Mechanism of alkene epoxidation." Thesis, University of Cambridge, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.604836.
Full textAbstract:
Heterogeneous silver catalysed ethene epoxidation is a strategically important selective oxidation giving rise to ethene epoxide a versatile monomer that is largely converted to glycols and used as antifreeze. Several aspects of this commercially important reaction were investigated using electrochemical promotion, a technique which involves electropumping of ions from a solid ion-conducting electrolyte to the surface of a porous catalytically active metal film. The most notable result in this work from ethene epoxidation was the elucidation of the NOx promotion effect. It was shown that adsorbed alkali and parts per million levels of nitric oxide added in the gas feed were minimum and sufficient conditions for the appearance of this phenomenon. Another commercially daunting and scientifically challenging reaction that was studied in this work was the heterogeneous propene epoxidation on silver catalysts. Using electrochemical promotion this work has shown that ethene and propene epoxidation react in a very different and contrasting manner to the addition of cholorine (CI), alkali and nitric oxide (NO) promoters. Basically potassium (K) alone is bad for ethene epoxide (EO), good for propene epoxide (PO), CI is good for EO, indifferent for PO, K+CI is good for EO, bad for PO and K+NO is good for EO, bad for PO. X-ray photoelectron spectroscopic investigation of the silver catalyst revealed that the substantially different state of oxygenation of the silver subsurface region could be the origin of the very different selectivity observed with these two alkenes. The underlying reason for the observed promotion in selectivity with adsorbed chlorine in ethene epoxidation was investigated by studying the effect of all four halogen promoters’ viz., fluorine, chlorine, bromine and iodine on supported silver on alumina catalysts. It was found that chlorine is the best promoter amongst them all. The behaviour of the halogens had a direct bearing to their electron affinity. And it seems that electronic affects are at work and geometric effects due to site blocking can be ruled out.
24
Anthonypillai, V. "Cytotoxic mechanism of chlorpromazine." Thesis, University of East London, 2001. http://roar.uel.ac.uk/3653/.
Full textAbstract:
Chlorpromazine (CPZ), a phenothiazine derivative, which has been extensively used in the treatment of schizophrenia for the last 50 years, also has recently been reported to have anticancer potential. Though it is one of the widely publicised compounds the information on the mechanism of its cytotoxicity is limited. Hence, an in vitro investigation was undertaken to study its cytotoxic mechanism. In a time and dose related study in SA3T3 cells the early statistically significant cytotoxicity was measured after a six-hour exposure with 50 uM and above (maximum concentration applied was 100 uM). The cytotoxicity increased with time and after 24 hours even 10 uM produced significant cytotoxicity and the I/C50 concentration was 40 uM. CPZ was found to induce dose-dependent statistically significant DNA single strand breaks in SA3T3 cells two hours before cell viability loss was measured, but no double strand breaks was noticed. The cytotoxic response in the presence of proadifen revealed that CPZ, but not any of its a number of metabolites, as suggested by many authors, is the molecule responsible for the cytotoxicity. Nordihydroguaiaretic acid, a lipoxygenase inhibitor, known to induce N-demethylation and N-polydemethylation of tertiary and quaternary amines potentiated the cytotoxicity of CPZ. Potentiation of CPZ cytotoxicity was seen also in the presence of clorgyline, a monoamine oxidase (A) inhibitor. Increased cytotoxicity in the presence of these agents indicates that the dimethylamino moiety of the dimethylaminopropyl side chain of CPZ plays an important role in the process. Although the importance of dimethylamino moiety in the cytotoxicity of CPZ has not been previously reported, established cytotoxic drugs like dacarbazine, tamoxifen and ethylenimines possess this group(s) in their structure. Flow cytometric analysis and other cytotoxicity measurements have indicated that the cytotoxicity induced by CPZ is biphasic that at 50 uM and above it induces cell death and at 40 uM and below it inhibits cell proliferation. The cytostatic effect of 40 uM CPZ is the same as that induced by 25-150 uM cisplatin, 6-50 juM vinblastin or 12.5- 200 uM doxorubicin. None of these compounds potentiated the cytotoxicity of CPZ but 30 jaM menadione, which causes double strand breaks in SA3T3 cells, increased the cytotoxicity of 70-100 uM CPZ. However, all the cytotoxic effects remained reversible up to the first four hours, for it was possible to restore total cell viability by removing CPZ from the extracellular medium after the said period. A fluorimetric analysis was developed, using 2',7'-dichlorodihydroxy fluorescein diacetate to measure free radical generation, which turned out to be useful in assessing the redox status of cells. Thus CPZ was found to raise the redox status of SA3T3 cells while keeping the cellular glutathione (GSH) concentration unaltered. Involvement of reactive oxygen species in CPZ mediated cytotoxicity was investigated. The OH radical scavengers: sodium benzoate, ot-tocopherol, ascorbic acid or retinol; the iron chelator: deferoxamine; the iron and copper chelator: 1,10-phenanthroline; O2 inhibitors: superoxide dismutase or diphenyline iodonium chloride; H2O2 inhibitors: catalase, or sodium azide; or the singlet oxygen quencher: 2,2,6,6-tetramethyl 4- piperidone gave no protection against CPZ cytotoxicity. There was no nitric oxide generated in CPZ treated SA3T3 cells and the peroxidase inhibitor sodium azide did not give any protection. Thus, the involvement of peroxinitrite or hypochloride anion as cytotoxicity mediators also was excluded. tertiary-Butyl hydroperoxide (t-BH)-mediated cytotoxic response was fully restored by CPZ though the cells died within the next two hours. The cytotoxic effect of CPZ in precision cut kidney slices of Wistar rats was found to be greater than that of liver slices. CPZ (100 uM) abolished lipid peroxidation and decreased lactate dehydogenase leakage induced by 1.5 mM t-BH in both kidney and liver tissue slices. However, in contrast to the findings in SA3T3 cells, CPZ inhibited GSH, though not to the extent of causing cytotoxicity, and the MTT assay did not show any protective effect in the said tissue slices. The relevance of all these findings in establishing the cytotoxic mechanism of CPZ is discussed. Since induction of cytotoxicity is a beneficial effect in anticancer chemotherapy the significance of the mechanisms and cytotoxicity of CPZ in cancer treatment is also discussed.
25
Perryman, L. J. "Cavity growth mechanism maps." Thesis, University of Surrey, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381676.
Full text
26
Gao, Connie W. (Connie Wu). "Automatic reaction mechanism generation :." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104205.
Full textAbstract:
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Chemical Engineering, 2016.Cataloged from PDF version of thesis.
Includes bibliographical references.
Growing awareness of climate change and the risks associated with our society's dependence on fossil fuels has motivated global initiatives to develop economically viable, renewable energy sources. However, the transportation sector remains a major hurdle. Although electric vehicles are becoming more mainstream, the transportation sector is expected to continue relying heavily on combustion engines, particularly in the freight and airline industries. Therefore, research efforts to develop cleaner combustion must continue. This includes the development of more efficient combustion engines, identification of compatible alternative fuels, and the streamlining of existing petroleum resources. These dynamic systems have complex chemistry and are often difficult and expensive to probe experimentally, making detailed chemical kinetic modeling an attractive option for simulating and predicting macroscopic observables such as ignition delay or CO₂ concentrations. This thesis presents several methods and applications towards high fidelity predictive modeling using Reaction Mechanism Generator (RMG), an open source software package which automatically constructs kinetic mechanisms. Several sources contribute to model error during automatic mechanism generation, including incomplete or incorrect handling of chemistry, poor estimation of thermodynamic and kinetics parameters, and uncertainty propagation. First, an overview of RMG is presented along with algorithmic changes for handling incomplete or incorrect chemistry. Completeness of chemistry is often limited by CPU speed and memory in the combinational problem of generating reactions for large molecules. A method for filtering reactions is presented for efficiently and accurately building models for larger systems. An extensible species representation was also implemented based on chemical graph theory, allowing chemistry to be extended to lone pairs, charges, and variable valencies. Several chemistries are explored in this thesis through modeling three combustion related processes. Ketone and cyclic ether chemistry are explored in the study of diisoproyl ketone and cineole, biofuel candidates produced by fungi in the decomposition of cellulosic biomass. Detailed kinetic modeling in conjunction with engine experiments and metabolic engineering form a collaborative feedback loop that efficiently screens biofuel candidates for use in novel engine technologies. Next, the challenge of modeling constrained cyclic geometries is tackled in generating a combustion model of JP-10, a synthetic jet fuel used in propulsion technologies. The model is validated against experimental and literature data and succeeds in capturing key product distributions, including aromatic compounds, which are precursors to polyaromatic hydrocarbons (PAHs) and soot. Finally, oil-to-gas cracking processes under geological conditions are studied through modeling the low temperature pyrolysis of the heavy oil analog phenyldodecane in the presence of diethyldisulfide. This system is used to gather mechanistic insight on the observation that sulfur-rich kerogens have accelerated oil-to-gas decomposition, a topic relevant to petroleum reservoir modeling. The model shows that free radical timescales matter in low temperature systems where alkylaromatics are relatively stable. Local and global uncertainty propagation methods are used to analyze error in automatically generated kinetic models. A framework for local uncertainty analysis was implemented using Cantera as a backend. Global uncertainty analysis was implemented using adaptive Smolyak pscudospcctral approximations to efficiently compute and construct polynomial chaos expansions (PCE) to approximate the dependence of outputs on a subset of uncertain inputs. Both local and global methods provide similar qualitative insights towards identifying the most influential input parameters in a model. The analysis shows that correlated uncertainties based on kinetics rate rules and group additivity estimates of thermochemistry drastically reduce a model's degrees of freedom and can have a large impact on model outputs. These results highlight the necessity of uncertainty analysis in the mechanism generation workflow. This thesis demonstrates that predictive chemical kinetics can aid in the mechanistic understanding of complex chemical processes and contributes new methods for refining and building high fidelity models in the automatic mechanism generation workflow. These contributions are available to the kinetics community through the RMG software package.
by Connie W. Gao.
Ph. D.
27
Allard, Nicholas (Nicholas A. ). "Compliant mechanism learning toolkit." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/36293.
Full textAbstract:
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.Includes bibliographical references (p. 43).
This thesis concerns a toolkit designed to assist in learning the behavior of complaint mechanisms. In the design of complaint mechanisms, increasingly complicated designs behave in ways that are harder to intuitively predict. This kit would allow for the rapid construction and disassembly of mechanisms with various constraint arrangements without the need to fabricate new models for each arrangement. This project includes the prototype of such a kit that would be manufactured for use in a classroom setting. The kit itself includes plates used to simulate a rigid ground, flexible components that can be mounted at variable angles to flat surfaces, and rigid stages to be connected to ground by the flexible constraint elements. These components are attached to each other using magnets, which allow them to be completely disassembled for rearrangement or storage. The resulting prototype worked roughly according to expectations. Rigid components attached to the kit walls with the flexible elements would translate about 0.3 inches without issue. The dynamic response of these displacements was very visible.
(cont.) Rotations of rigid stages, however, moved a few degrees and would not show any pure dynamic response after being released. In terms of viewing degrees of freedom, however, the kit was helpful in the visualization process.
by Nicholas Allard.
S.B.
28
Balestrieri, Filippo. "Essays on mechanism design." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/43763.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Economics, 2008.Includes bibliographical references.
This thesis is a collection of three essays on mechanism design. In Chapter 1, we consider a general Informed Principal Problem in the context of procurement. Both the potential suppliers and the buyer hold some private information: each supplier knows his cost of production, the buyer knows how much each supplier's product fits her technical requirements. We derive the optimal auction in this environment, and analyze the implementation problem with special emphasis on three aspects that are particularly relevant in real practice: privacy protection, dynamic consistency, and simplicity. We design a dynamic mechanism, the Modified English Auction, that implements the optimal auction outcome, is privacy preserving, dynamically consistent, and simple. Chapter 2 is a joint work with Joao Leao. How do mechanisms like hotwire.com work? What is their economic impact on the existing markets of hotel rooms, airplane tickets, and rental cars? We address these questions by investigating whether lotteries over the basic goods can be profitably used by any of the market participants. We consider lotteries in which the buyers win a prize for sure, but they do not know which one. Our main finding is that the perfect cartel always uses lotteries to maximize its profits. Moreover, under specific conditions, the entry of a lottery provider in a competitive market may bring the existing firms closer to the cartel solution. The introduction of lotteries has two effects. First, the firms can use them to price-discriminate their consumers. Second, the firms can use lotteries to cover a larger part of the market. Indeed, the consumers who find the basic goods too expensive may still want to buy cheaper lottery tickets.
(cont.) In Chapter 3 we initiate the formal analysis of the First Price-First Score Auction in a general context where the auctioneer is a seller and two bidders compete to buy one indivisible good. The auctioneer's preferences are assumed to directly depend on the identity of the buyer to whom the good is allocated. In this auction, the bidders submit monetary bids, and then the seller decides which bid to accept after comparing the bidders' scores. A particular class of auction we focus on have simple scoring functions: each bidder's score is given by the summation of his bid and a bidder-specific additional parameter. Our main goal is to obtain the specification of the problem that generates a closed-form analytical solutions for the bidding strategies. The task is complicated as there are at least two sources of asymmetries inherent to the problem that can quickly lead to intractable formulas. The main contribution of this work is to provide closed formulas for the inverse bidding functions. Our results generalize the comparison of bidding strategies in asymmetric first price auctions obtained by Maskin and Riley (2002). Even if the asymmetry between the bidders is exogenously introduced by the auctioneer, in equilibrium the disadvantaged bidder bids more aggressively. We are also able to determine the ranges of bids that can be submitted by the two bidders. They are actually different, and their extremes depend on the extra-bid parameter.
by Filippo Balestrieri.
Ph.D.
29
Condorelli, D. "Essays in mechanism design." Thesis, University College London (University of London), 2010. http://discovery.ucl.ac.uk/19411/.
Full textAbstract:
In chapter one I study the welfare optimal allocation of a number of identical indivisible objects to a set of heterogeneous risk-neutral agents under the hypothesis that money is not available. Agents have independent private values, which represent the maximum time that they are willing to queue to obtain a good. I show that a priority list is optimal when hazard rates of the distributions of values are increasing. Instead, queues are optimal in a symmetric setting with decreasing hazard rates. In the second chapter, I study a model in which the use of both market (e.g. auctions) and non-market mechanisms (e.g. lotteries and priority lists) for the allocation of scarce public resources can be rationalized. Agents are risk-neutral and heterogeneous in terms of their monetary value for a good and their opportunity cost of money. The designer wants to allocate a set of goods to the agents with the highest values. The designer screens agents on the basis of their observable characteristics, and extracts information on their willingness to pay using market mechanisms. I show that both market and non-market mechanism can be optimal depending on the prior information. In the last chapter I study a dynamic market model where trade for a single object is bilateral, constrained by an exogenous network structure and conducted under asymmetric information. The model provides a insights into how the position of a player in a network affects his bargaining outcomes. First, traders who provide monopolistic access to valuable portions of the trading network become intermediaries, and obtain a payoff advantage. Second, the earlier an intermediary obtains the object in the trading chain, the higher is his expected payoff. Finally, inefficient outcomes are possible, and are jointly caused by the network structure and by asymmetries of information.
30
Goncharova, T. "Mechanism of wastes management." Thesis, Вид-во СумДУ, 2007. http://essuir.sumdu.edu.ua/handle/123456789/17412.
Full text
31
Кобякова, Ірина Карпівна, Ирина Карповна Кобякова, and Iryna Karpivna Kobyakova. "Linguistic mechanism of humour." Thesis, Національного педагогічного університету імені М.П. Драгоманова, 2019. http://essuir.sumdu.edu.ua/handle/123456789/72792.
Full textAbstract:
Стаття присвячена розгляду проблеми гумору і шляхів його перекладу в тексті. Серед мовленнєвих функцій особливе місце займає лінгвлкреативна функція, яка обумовлена мисленням.Объект исследования представлен универсальной категорией юмора, предмет – оязыковлением ее глобальной структуры в английском дискурсе. Категория юмора анализируется в режиме словоцентричного и текстоцентричного подходов к эмпирическому материалу в модусах языка и речи.
Humour is a universal phenomenon touching upon heterogeneity of language modi. Humour subsystem is on the constant move and development. Basic tenets of humour are backgrounded by relevant situations, words, texts, genres and discourses.
32
Pearlberg, Daniel. "Causation, Mechanism and Mind." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1430829433.
Full text
33
Jia, Yu. "Heavy-quark recombination mechanism /." The Ohio State University, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=osu1486462067841772.
Full text
34
Rosar, Frank. "Essays in mechanism design." [S.l. : s.n.], 2007. http://nbn-resolving.de/urn:nbn:de:bsz:180-madoc-21408.
Full text
35
Amore, Benny Michael. "Mechanism of carbamazepine teratogenicity /." Thesis, Connect to this title online; UW restricted, 1996. http://hdl.handle.net/1773/7939.
Full text
36
An, Sungwhan. "Mechanism of coronavirus transcription /." Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.
Full text
37
Zeinali, Amin. "Thaw Mechanism in Subgrades." Licentiate thesis, Luleå tekniska universitet, Geoteknologi, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-70979.
Full textAbstract:
Freezing-thawing, changes the properties of soil due to the phase change of the water in the soil body. Freezing-thawing cycles in the soil have been studied for several decades including extensive laboratory research. In this study, the main focus is thawing based on laboratory investigation. The soil used in the laboratory study is taken from a minor road where an additional field study has been carried out. A freezing-thawing laboratory apparatus is manufactured and used in order to get better understanding of the freezing-thawing process. The apparatus is designed for cylindrical sample, one dimensional heat flow, freezing/thawing from top to bottom, water supply from bottom (access to external water) and possible to apply overburden load. he laboratory tests were conducted at similar soil samples at different boundary conditions. Water is liberated in the thawing zone of the sample. During thawing the only drainage path is to the surface, however, water migrates upwards even when entire soil is thawed. Upwards water migration after thawing period can be due to the changes in thawed soil properties such as permeability and fine particles redistribution. The rate of thawing is a very important factor for thawing conditions. At low thawing rate the drainage capacity of sample is sufficient to drain the liberated water from ice. Moreover, freezing condition i.e. access to water, has high impact on thawing process. If the volume of ice lenses is high,the thawed soil fluidizes as the water migrates upwards. Pore pressure transducers will be added to the apparatus for further investigation regarding both freezing and thawing. The field study has been conducted in order to study thaw behavior in low volume road embankment. The scope of the study is to investigate the thaw weakening progress by Falling Weight Deflectometer (FWD) and Dynamic Cone Penetration (DCP) tests on low volume embankment road near Luleå,northern Sweden. The results from methods is compared and the differences in how they are capturing the thawing is discussed. DCP which is known as an easy and cheap method to estimate stiffness of soil layers is applied to estimate thawing period and the layer which thaw weakening takes place at. Stiffness gained by back calculation of FWD results which is performed on the same road embankment and same period of time DCP test is done.
38
Hyatt, Lance Parker. "Designing Developable Mechanisms on Conical and Cylindrical Developable Surfaces." BYU ScholarsArchive, 2020. https://scholarsarchive.byu.edu/etd/8467.
Full textAbstract:
The research results presented in this thesis provide tools and methods to aid in the design of developable mechanisms. This work will help engineers design compact mechanisms onto developable surfaces, making it possible for them to be used in future applications. The thesis introduces terminology and definitions to describe conical developable mechanisms. Models are developed to describe mechanism motion with respect to the apex of the conical surface, and connections are made to cylindrical developable mechanisms using projected angles. The Loop Sum Method is presented as an approach to determine the geometry of the cone to which a given spherical mechanism can be mapped. A method for position analysis is presented to determine the location of any point along the link of a mechanism with respect to the conical geometry. These methods are also applied to multiloop spherical mechanisms. This work created tools and methods to design cylindrical and conical developable mechanisms from flat, planar patterns. Equations are presented that relate the link lengths and link angles of planar and spherical mechanisms to the dimensions in a flat configuration. These flat patterns can then be formed into curved, developable mechanisms. Guidelines are established to determine if a mechanism described by a flat pattern can exhibit intramobile or extramobile behavior. A developable mechanism can only potentially exhibit intramobile or extramobile behavior if none of the links extend beyond half of the flat pattern. The behavior of a mechanism can change depending on the location of the cut of the flat pattern. Different joint designs are discussed including lamina emergent torsional (LET) joints. It is shown that developable mechanisms on regular cylindrical surfaces can be described using cyclic quadrilaterals. Mechanisms can exist in either an open or crossed configuration, and these configurations correspond to convex and crossed cyclic quadrilaterals. Using equations developed for both convex and crossed cyclic quadrilaterals, the geometry of the reference surface to which a four-bar mechanism can be mapped is found. Grashof mechanisms can be mapped to two surfaces in open or crossed configurations. The way to map a non-Grashof mechanism to a cylindrical surface is in its open configuration. Extramobile and intramobile behavior can be achieved depending on selected pairs within a cyclic quadrilateral and its position within the circumcircle. Selecting different sets of links as the ground link changes the potential behavior of the mechanism. Different cases are tabulated to represent all possibilities.
39
Greň, Martin. "Návrh a pevnostní kontrola systému řízení letounu TL 4000." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-232028.
Full textAbstract:
Tato diplomová práce se zabývá návrhem mechanismu řízení letounu TL 4000, určení sil působících na jednotlivé součásti řízení a jejich pevnostní analýzou. V této práci jsou vypracovány všechny tři složky řízení a to tak, aby vyhovovaly stavebnímu předpisu CS 23.
40
Freisleben, Pavel. "Dvouválcový zážehový motor s excentrickým klikovým mechanismem pro osobní vozidla." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-232115.
Full textAbstract:
This thesis deals with forces of the crank mechanism. The aim of this work is to find the right value of the eccentricity of the crank mechanism, which will have a positive effect on the size and course of forces that cause friction losses in the crank mechanism. Next solves this balancing eccentric unit. The last part deals with the design and strength check of the crankshaft considering torsional vibration.
41
Mishima, Hirokazu. "Studies Based on Statistical Mechanics for Mechanism of Multidrug Efflux of AcrA/AcrB/TolC." Kyoto University, 2015. http://hdl.handle.net/2433/199416.
Full text
42
Cannon, David Wayne. "Command generation and inertial damping control of flexible macro-micro manipulators." Thesis, Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/18212.
Full text
43
Sun, Kun. "Computer-aided creative mechanism design /." [S.l.] : [s.n.], 1994. http://library.epfl.ch/theses/?nr=1271.
Full text
44
Lewinski, Mary Kathleen. "Retroviral integration mechanism and consequences /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2005. http://wwwlib.umi.com/cr/ucsd/fullcit?p3187814.
Full textAbstract:
Thesis (Ph. D.)--University of California, San Diego, 2005.Title from PDF title page (viewed October 21, 2005) Vita. Includes bibliographical references (p. 189-214). Available online via ProQuest Digital Dissertations.
45
Tatarski, Miloš. "Molecular mechanism of dBigH1 action." Doctoral thesis, Universitat de Barcelona, 2018. http://hdl.handle.net/10803/663021.
Full textAbstract:
INTRODUCTION:
For decades it was known that many species contain embryo specific linker histone H1 variants that replace the somatic H1 during early embryogenesis. This is especially important because the early embryo shows typically zero to very little activity of transcription, and the first cleavages of the embryo depend exclusively on maternally deposited factors that are important for transcription and chromatin assembly. The first species shown to contain an embryo specific histone H1 was the sea urchin. Other species like the mouse, Xenopus or the zebrafish followed. Even in humans there are embryo specific H1 variants. Drosophila seemed to be an exception to this, until in 2013 the first linker histone H1 variant was discovered that was called dBigH1. Like other embryo H1 variants, dBigH1 is expressed in the early embryo and disappears when cellularization starts and it gets replaced by the somatic H1. Likewise, to its counterparts in other species, dBigH1 is responsible for the inhibition of transcription during the early stage of fly development.
OBJECTIVES:
In this thesis, we addressed the questions about the mechanism of inhibition of dBigH1 as well as the factors that are responsible for its deposition into chromatin.
RESULTS:
To answer the first question, we used an in vitro system for chromatin reconstitution based on an extract from early Drosophila embryos (DREX) that contains dBigH1 and all other factors needed for proper chromatin assembly. We then used the reconstituted chromatin in transcription experiments using HeLa nuclear extract that contains all factors needed for transcription.
We saw that transcription for chromatin reconstituted in DREX could be reduced when the extract was previously depleted from dBigH1 using specific antibodies against it. By adding back recombinant dBigH1 to the depleted extract we were able to restore the initial lever of transcription. This showed us that dBigH1 was the repressive factor, as it was already confirmed in vivo.
We then used a truncated construct of dBigH1 where we depleted the N-terminal domain of the protein. This was of particular interest as the N-terminal region of dBigH1 is the one that differs most form the somatic H1. It is much longer and more importantly very enriched with acidic residues, something that is very unique amongst all embryo specific H1 variants. We saw that when using the truncated construct, transcription was inhibited to a much lesser extent than with the full length dBigH1, proposing that the N-terminal domain is indeed responsible for the inhibition of transcription.
To answer the second question about the factors needed for dBigH1 deposition, we used Drosophila testis to study dBigH1 in vivo. dBigH1 shows a very similar expression pattern in testis as the chromatin remodeler ACF1. This is why we decided to investigate a possible interaction between those two proteins. Additionally, we knew that ACF1 uses NAP1 as a histone chaperone for H1 in some species, so we also asked if NAP1 could play a role in dBigH1 deposition as well.
Indeed, we saw that when using flies deficient for ACF1 we see much less dBigH1 in the testis tip where the germal stem cells (GSC) reside, suggesting that ACF1 plays an important role in dBigH1 deposition. In accordance, we see more dBigH1 in the GSCs when using flies overexpressing ACF1. At the same time, we can see that when depleting NAP1 from DREX, we see more dBigH1.
46
NISHIMURA, Makoto, and MU TANG. "Analysis of China's Development Mechanism." 名古屋大学大学院経済学研究科, 2009. http://hdl.handle.net/2237/11967.
Full text
47
Long, Yan. "Essays on robust mechanism design." Thesis, University of Glasgow, 2016. http://theses.gla.ac.uk/7472/.
Full textAbstract:
Chapter 1: Under the average common value function, we select almost uniquely the mechanism that gives the seller the largest portion of the true value in the worst situation among all the direct mechanisms that are feasible, ex-post implementable and individually rational. Chapter 2: Strategy-proof, budget balanced, anonymous, envy-free linear mechanisms assign p identical objects to n agents. The efficiency loss is the largest ratio of surplus loss to efficient surplus, over all profiles of non-negative valuations. The smallest efficiency loss is uniquely achieved by the following simple allocation rule: assigns one object to each of the p−1 agents with the highest valuation, a large probability to the agent with the pth highest valuation, and the remaining probability to the agent with the (p+1)th highest valuation. When “envy freeness” is replaced by the weaker condition “voluntary participation”, the optimal mechanism differs only when p is much less than n. Chapter 3: One group is to be selected among a set of agents. Agents have preferences over the size of the group if they are selected; and preferences over size as well as the “stand-outside” option are single-peaked. We take a mechanism design approach and search for group selection mechanisms that are efficient, strategy-proof and individually rational. Two classes of such mechanisms are presented. The proposing mechanism allows agents to either maintain or shrink the group size following a fixed priority, and is characterized by group strategy-proofness. The voting mechanism enlarges the group size in each voting round, and achieves at least half of the maximum group size compatible with individual rationality.
48
Attarzadeh, Yazdi Ghassem. "Molecular mechanism of glucocorticoid action." Thesis, University of Edinburgh, 2006. http://hdl.handle.net/1842/26161.
Full textAbstract:
The aim of this thesis project was to investigate the mechanisms by which glucocorticoid hormones regulate the activity of BK channels in human embryonic kidney 293 (HEK293) cells as the model system for glucocorticoids-action. It was shown that glucocorticoids act via endogenously expressed type II receptors in a concentration- and time-dependent manner in these cells. Dexamethasone (100 nM) had no significant effect on Dexras1 mRNA but significantly increased serum- and glucocorticoid-induced protein kinase 1 (SGK-1) mRNA. Biochemical analysis showed that SGK-1 protein is increased by dexamethasone in a Triton X-100 insoluble fraction. Further work was directed toward analysing the possible association of SGK-1 and protein phosphatases with two BK channel α-subunit variants: ZERO-BK and STREX-BK, the latter contains the 59 amino-acid splice insert encoded by the stress hormone induced exon (STREX). HEK293 cells stably expressing the respective channel subunits were analysed. Immunoprecipitations with antisera directed against the BK α-subunits showed that protein phosphatase 2A (PP2A) but not SGK-1 is constitutively associated with the STREX as well as the ZERO variant BK channel. Furthermore, the cytoplasmic C-terminal segment of the STREX-BK channel was necessary for cell-surface expression of the channel and the association of the channel with PP2A. Dexamethasone, failed to change the apparent amount of immunoreactive PP2A co-immunoprecipitating with the channel. In conclusion: SGK-1 but not Dexras1 is a protein rapidly induced by dexamethasone in HEK293 cells. PP2A but not SGK-1 is in complex with both ZERO and STREX-BK channels, and dexamethasone does not alter this association. The cytoplasmic tail of the BK channels is essential for PP2A interaction.
49
Morkel, Jacqueline. "Kimberlite weathering mineralogy and mechanism /." Pretoria : [s.n.], 2006. http://upetd.up.ac.za/thesis/available/etd-07212007-104241.
Full text
50
KOBAYAKAWA, HIROYUKI, ICHIRO TAKAI, SHIGERU NAKAI, TAKAHIRO SHINZATO, and KENJI MAEDA. "Mechanism of Dialysis-induced Hypotension." Nagoya University School of Medicine, 1992. http://hdl.handle.net/2237/17518.
Full text