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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Estudio de la estructura y función de la familia de proteínas quinasas C

Sánchez Bautista, Sonia 04 July 2007 (has links)
La Proteína Quinasa C (PKC) juega un papel fundamental en la regulación del crecimiento celular. Estas proteínas están implicadas en diferentes vías intracelulares que son consideradas como dianas para el tratamiento contra el cáncer. Atendiendo a las propiedades enzimáticas, las PKC se clasifican en tres grandes subfamilias: clásicas, nuevas y atípicas. En las PKC clásicas, el dominio C2 es un motivo regulador que responde a señales de Ca2+ intracelulares. Este dominio presenta un motivo denominado región rica en lisinas que interacciona con fosfolípidos acídicos. Los resultados de esta tesis demuestran que la afinidad de este dominio por fosfolípidos como el PIP2 es mayor frente a otros de la misma naturaleza. El dominio C2 de las PKC nuevas se une a fosfolípidos cargados negativamente de modo Ca2+-independiente. Nuestro estudio demuestra que la interacción de este dominio con las membranas es principalmente electrostática con una pequeña contribución de interacciones hidrofóbicas. Por otra parte, el estudio de la estructura secundaria del dominio catalítico de la PKC mostró una elevada proporción de hélice . La adición de Mg2+-ATP provocó un mayor efecto protector frente a la desnaturalización térmica. / Protein kinase C (PKC) is a family of related protein kinases that plays an important role in regulating cell growth. These protein kinases are involved in several intracellular pathways that end in transcription and are considered to be potential targets for anticancer therapy. The mammalian isoenzymes have been grouped into three subfamilies according to their enzymatic properties: classical, novel and atypical.The C2 domain is a regulatory sequence motif and is a targeting domain that responds to intracellular Ca2+ signals in classical protein kinases. This domain presents a motif named the lysine-rich cluster that interacts with acidic phospholipids. The results demonstrate that PIP2 interacts with the C2 domain of PKCα in a different way to that described for other phospolipids.C2 domain in novel PKC binds to negatively charged phospholipid vesicles in a Ca2+-independent manner. Our study confirms that the main way in which C2-PKC interacts with membranes is electrostatic in nature, with a very small contribution on the part of hydrophobic interactions.The secondary structure of catalytic domain from atypical PKC showed a high contribution of -helix component. In addition, Mg2+-ATP significantly altered the denaturation pattern of this domain because it protected against denaturation.
42

Biochemistry and physiological role of otoferlin / Biochemie und physiologische Funktion von Otoferlin

Reuter, Kirsten 10 October 2011 (has links)
No description available.
43

Phylogenetic studies of the vesicular fusion machinery / Phylogenetische Studien der vesikulären Fusionsmaschinerie

Kienle, Nickias 12 July 2010 (has links)
No description available.
44

Steroid signalling in the human ovarian surface epithelium wound healing

Papacleovoulou, Georgia January 2009 (has links)
The human ovarian surface epithelium (hOSE) is a cell monolayer that covers the surface of the ovary. Natural events like incessant ovulation, associated reproductive hormone action prior to and post-ovulation, along with the ovulationassociated inflammation, that result in injury and repair of hOSE, are considered to have a role in the development of epithelial ovarian cancer (EOC). Progesterone is apoptotic and anti-inflammatory, whereas androgens appear cytoproliferative for hOSE. Local generation of these steroid hormones is subject to 3β-hydroxysteroid dehydrogenase (3β-HSD) activity. Moreover, action of these hormones is achieved through coupling to their cognate receptors, progesterone (PR) and androgen receptors (AR). The overall aim of this thesis is to elucidate in vitro the regulation of progesterone and androgen biosynthesis and downstream signalling during the injury and repair of primary hOSE cells that were collected from pre-menopausal women who underwent surgery for benign gynaecological disorders. Injury was mimicked by treatment of cells with several pro-inflammatory cytokines, whereas repair was mimicked with T-lymphocyte, ‘anti-inflammatory’ cytokines. Immunohistochemical studies showed immunodetectable 3β-HSD in the human ovarian cell surface of whole ovary and three-week cultured hOSE cells, establishing 3β-HSD expression in vivo and in vitro. Cross-reaction of the 3β-HSD antibody with both enzyme isoforms did not allow investigation of isoform expression pattern. However, mRNA transcriptional studies with isoform specific primers and probe sets for semi-quantitative (sq) and quantitative (q) PCR revealed expression of both isoforms in hOSE cells; 3β-HSD1 mRNA was expressed at higher levels relative to 3β-HSD2 mRNA in accordance with the preference of this isoform in peripheral non-steroidogenic tissues. Of the cytokines tested, only IL-1α and IL-4 affected 3β-HSD expression. IL- 1α suppressed 3β-HSD1 mRNA, whereas it up-regulated 3β-HSD2 mRNA as assessed with qPCR, without though affecting total 3β-HSD protein and activity levels as assessed with western immunoblotting and radiometric activity assays, respectively. IL-1α did not affect AR or PR mRNA levels, suggesting a balance in androgen and progesterone biosynthesis during post-ovulatory wounding. IL-4 massively induced 3β-HSD1 and 3β-HSD2 mRNA and total 3β-HSD protein and activity. It also attenuated AR mRNA and protein, without affecting PR mRNA. Collectively, these data demonstrate that IL-4 sustains progesterone rather than androgen signalling and this may be part of the anti-inflammatory steroid action that protects hOSE from genetic damage. IL-1α effects appear to be mediated by NF-κB signalling pathway. PI-3K and p38 MAPK appeared involved in IL-1α-induced 3β- HSD2. IL-4-induced 3β-HSDs required STAT-6 and PI-3K pathways and also p38 MAPK at the case of 3β-HSD2. IL-4-attenuated AR was reversed by a p38 MAPK inhibitor. These data suggest that steroid signalling by IL-1α and IL-4 involve multiple signalling pathways. In primary EOC, 3β-HSD1 and 3β-HSD2 transcripts were attenuated relative to hOSE cells, suggestive of an acquired feature of neoplastic transformation. However, both transcripts could be restored after IL-4 treatment, attesting a therapeutic advantage of this cytokine. In conclusion, we have shown that 3β-HSD is under inflammatory control during ovarian post-ovulatory wound healing of hOSE. IL-1α- and IL-4-mediated 3β-HSD1 and 3β-HSD2 are regulated by multiple signalling pathways. Also, IL-4 was identified as an anti-inflammatory agent in hOSE with putative therapeutic benefit in malignancy.
45

Network centric warfare: a command and control perspective

Lim, Soon-Chia 03 1900 (has links)
Approved for public release, distribution is unlimited / This paper seeks to analyze the command and control issues arising from the advent of NCW. It aims to contribute to a practical understanding of the concept and an implementation approach for NCW by attempting to provide an analytical framework, the various options/models, and considerations across the spectrum of NCW issues. While information superiority is not a new concept, the blazing speed of advancement in information technologies has brought about dramatic changes to our lifestyles and profound changes in the conduct of modern warfare. This led to the birth of Network Centric Warfare (NCW). NCW offers great opportunities to dramatically enhance combat prowess by exploiting shared situational awareness, increased speed of command, improved systems' lethality and survivability, and greater flexibility achieved through self synchronization. However, these revolutionary changes do not depend on technology alone. In order to achieve the full promise of NCW, the entire span of elements ranging from organization, doctrine, and operational concepts to training must co-evolve. The success of NCW is dependent on aligning the organization's commitment, resources and efforts, fostering a learning and innovative culture, constructing a seamless, robust and secure infostructure, and establishing measures of effectiveness of C2. The journey to NCW is not a linear process, but rather a spiral developmental process. Continued evolution and efforts are required to shape and deliver the enhanced combat capability as the apex of maturity of the spiraling cone. / Lieutenant Colonel, Republic of Singapore Air Force
46

A Comparison of a Young and Older Adult Population of Computer Users' Recognition Rates of Different Tactons Using Modulation and Simple Waveforms as Stimulus Parameters.

Jimenez, Ricardo 01 January 2012 (has links)
Tactons are tactile cues, which work in conjunction with a vibrotactile device that is placed on the body, and mechanically produces sensations on the skin surface; this allows the sense of touch to be used in Human-Computer Interaction (HCI). Effective tacton parameters of stimuli have been identified for a young population. However, studies have shown that the detection of vibrations degrades as a natural part of the aging process. Furthermore, there are a variety of different vibrotactile devices, and studies have shown that vibrotactile device type can affect detection thresholds. This presents a challenge since detection thresholds and recognition rates of different tacton cues, using one device, may not correlate to those of another. There is limited research on the effectiveness of tacton parameters and detection thresholds of simple waveforms in an older population of computer users, when using the C2 Tactor from EAI systems. This work used the C2 Tactor and stimulus parameters similar to those which have been shown to be effective in a young population, and conducted a comparison study between a young population of computer users between 18 and 25 years old and an older population of computer users between 55 and 75 years old. The study compared both groups' detection thresholds of three different simple waveforms (sinusoidal, square, and sawtooth) and found a significant increase in detection threshold by the older group. In addition a comparison of both groups' recognition rates of modulated sinusoidal waveforms was conducted and it was found that the older group had a significant decrease in recognition rates of modulated sinusoidal waveforms. In addition, it was shown that increasing the amplitude significantly improved the recognition rate of the older test group. A significant amount of variance in detection threshold and tacton recognition rates was found in the older test group, particularly those over the age of 60. The results of this study clearly showed a correlation between age, detection threshold, and recognition rates of tactons. The study shows that detection threshold and recognition rate deficiencies of older adults are functions of frequency and amplitude and not waveform or device.
47

Coordination and Logistic Aspects in Computer Based Training for Emergency Situations

Nadeem, Hassam, Dastgeer, Usman January 2009 (has links)
<p>This report presents research study conducted at Linkoping University on coordination and logistics training design in simulation based environment.This study is based on C3Fire simulation environment for designing scenarios and simulations to train people for coordination and logistics handling under emergency situations. Related existing literature and theories about decision making, teamwork and situation awareness are studied and consulted to design new scenarios. Several scenarios were developed and initial experiments were conducted on these scenarios to check whether they meet intended behavior or not. Result of experiments proved success of scenario‟ design and these scenarios along their training goals, player and manager instructions are documented in report. It can be used to train and test team‟s ability for coordination and logistics aspects in emergency situations. Exhaustive testing of scenarios on large experiment base is left as future work.</p>
48

Coordination and Logistic Aspects in Computer Based Training for Emergency Situations

Nadeem, Hassam, Dastgeer, Usman January 2009 (has links)
This report presents research study conducted at Linkoping University on coordination and logistics training design in simulation based environment.This study is based on C3Fire simulation environment for designing scenarios and simulations to train people for coordination and logistics handling under emergency situations. Related existing literature and theories about decision making, teamwork and situation awareness are studied and consulted to design new scenarios. Several scenarios were developed and initial experiments were conducted on these scenarios to check whether they meet intended behavior or not. Result of experiments proved success of scenario‟ design and these scenarios along their training goals, player and manager instructions are documented in report. It can be used to train and test team‟s ability for coordination and logistics aspects in emergency situations. Exhaustive testing of scenarios on large experiment base is left as future work.
49

Novel Studies On The Chemoenzymatic Synthesis Of Polychlorinated Bicyclic Systems And The Synthesis Of C2 And C3 Symmetric Chiral Ligands

Turkmen, Yunus Emre 01 July 2006 (has links) (PDF)
Optically active polychlorinated bicyclic systems are important starting materials for the synthesis of complex target molecules. In the first part of the study, the syntheses of several racemic and meso hexachloronorbornene derivatives were executed successfully, starting from hexachlorocyclopentadiene. The enantio-enriched acetoxymethyl derivative (-)-2 and the hemiester (-)-6 were synthesized in high e.e. values by using several hydrolase type enzymes. The absolute configuration of (-)-2 was determined by transforming it to the corresponding norbornene derivative (-)-7 with known absolute configuration. In the second part of the study, C2 symmetric chiral ligand (-)-11 and C3 symmetric chiral triamide derivative (-)-12 were synthesized in high chemical yields starting from L-proline. In connection to these studies, the syntheses of the monoamide derivative (-)-14 and the C2 symmetric diamide derivative (-)-15 were achieved by using appropriate amounts of L-proline.
50

Fullerene im Strahlungsgleichgewicht - Untersuchungen in einem Quadrupolspeicher

Decker, Silvio 16 December 2009 (has links) (PDF)
Das wissenschaftliche Ziel der Arbeit ist die Untersuchung von optischen und chemischen Eigenschaften von kohlenstoffhaltigen Teilchen im besonderen Fullerene bei hohen Temperaturen. Die Arbeit behandelt im Detail den Aufbau und die Charakterisierung einer Messapparatur zur Untersuchung von Fulleren-Kationen. Nach einer kurzen Einführung zum Thema und einer Beschreibung des Aufbaus der Arbeit beginnt diese mit der Charakterisierung der Apparatur als Ganzes und ihrer Elemente. Dazu gehört die weiterentwickelte Sublimationsionenquelle, der Quadrupolspeicher und der Ionendetektor. Es werden eingehende Messungen zur Speicherung und zum Nachweis der absoluten Zahl von gespeicherten Ionen vorgestellt. Weiterhin wird das optische Nachweissystem bezüglich der Sammelleistung und des Empfindlichkeit eingehend untersucht. Nach der Einführung in die Apparatur wird die Verteilung der Ionen im Speicher näher beleuchtet und gezeigt, dass ein optischer Nachweis der Zahl gespeicherter Ionen möglich ist. Außerdem wird gezeigt, dass es gelingt die kinetische Temperatur der Ionen im Speicher, durch die geometrische Vermessung der Ionenverteilung zu bestimmen. Im weiteren wird auf die thermische Emission heißer C60+ näher eingegangen. Dazu wird ein klassisches dielektrisches Modell zur thermischen Emission vorgestellt. Es werden Messprinzipien zur Temperaturbestimmung der lasergeheizten Ionen erörtert und Messungen zur Temperatur des Ionenensembles präsentiert. Weiterhin werden Messungen zum C2-Verlust von C60+ als Funktion der Temperatur vorgestellt. Die experimentell ermittelte Aktivierungsenergie der C2-Verlustreaktion mit Ea = 2,3...5,4eV zeigt deutliche Abweichungen zu bekannten Literaturwerten. Die Ergebnisse dieser Messung werden mit einer nummerischen Simulation zur Energieverteilung im Ionenensemble diskutiert. Die Arbeit endet mit einer Zusammenfassung und einem Ausblick auf weitere experimentelle Möglichkeiten der Messmethode. / The scientific goal of this work is the study of optical and chemical properties of carbon containing particles especially fullerenes at high temperatures. This work covered the construction and characterization of the measuring apparatus for the investigation of fullerene cations. It follows a characterization of the apparatus and its elements after a short introduction and a description of the structure of this work. This involved the further developed sublimation ion source, the quadrupole trap and the ion detections system. Extensive measurements of the ion trapping and the proof of the absolute number of trapped ions are presented. Further on the optical detections system is characterized in depth regarding the collection efficiency and sensitivity. After the introduction in the apparatus the distribution of the ions inside the trap is closer examined. The possibility of the optical detections of the number of trapped ions is shown. Additionally it is pointed out that the kinetic temperature of the ions can be extracted by geometrical measurement of the ion distribution. Further on it is enlarged on the thermal emission of hot C60. For this a classical dielectric model for the thermal emission is presented. Measuring principals of the temperature determination of laser heated ions are discussed and temperature measurements of the ion ensemble are presented. Measurements of the C2-loss as function of the temperature are presented. The results of the extracted activation energy of Ea = 2.3...5.4eV for the C2-loss reaction of C60+ shows a discrepancy to literature results. The results of this measurements are discussed with help of an numerical simulation of the internal energy distribution of the ion ensemble. This work closes with a summery and an outlook of further experimental potentialities of the measuring method.

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