Dissertations / Theses on the topic 'Magnetic traps'
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Grady, Keith J. "Solar flare particle acceleration in collapsing magnetic traps." Thesis, University of St Andrews, 2012. http://hdl.handle.net/10023/2839.
Full textHowdyshell, Marci Lynn. "Micro-magnetic Structures for Biological Applications." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1408718613.
Full textEradat, Oskoui Solmaz. "New aspects of particle acceleration in collapsing magnetic traps." Thesis, University of St Andrews, 2014. http://hdl.handle.net/10023/11954.
Full textAskitopoulos, Alexis. "Polariton condensates in optical traps and strong magnetic fields." Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/386219/.
Full textPrikockis, Michael Vito. "Physics and Applications of Interacting Magnetic Particles: Effect of Patterned Traps." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1452073910.
Full textHan, Dian-jiun. "Bose-Einstein condensation of rubidium-87 atoms in a magnetic trap /." Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.
Full textChen, Aaron. "Imprinted Magnetic Traps for Study on Particle Fluctuation, Ordering and Microfluidic Applications." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1364490203.
Full textMurgia, David. "Microchip ion traps with high magnetic field gradients for microwave quantum logic." Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/48045.
Full textBaranov, O. O. "Control of Ion Density Distribution by Use of Magnetic Traps for Plasma Electrons." Thesis, Sumy State University, 2012. http://essuir.sumdu.edu.ua/handle/123456789/35384.
Full textMyers, Jessica Ann, and Jessica Ann Myers. "Hybrid Optical-Magnetic Traps for Studies of 2D Quantum Turbulence in Bose-Einstein Condensates." Diss., The University of Arizona, 2017. http://hdl.handle.net/10150/625625.
Full textThomas, Nicholas, and n/a. "Double-TOP trap for ultracold atoms." University of Otago. Department of Physics, 2005. http://adt.otago.ac.nz./public/adt-NZDU20070321.160859.
Full textStamper-Kurn, Dan M. (Dan Moses) 1971. "Peeking and poking at a new quantum fluid : studies of gaseous Bose-Einstein condensates in magnetic and optical traps." Thesis, Massachusetts Institute of Technology, 2000. https://hdl.handle.net/1721.1/129360.
Full textIncludes bibliographical references (leaves 253-272).
by Dan M. Stamper-Kurn.
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Physics, 2000.
Lane, Ryan A. "Charged Particle Transport and Confinement Along Null Magnetic Curves and in Various Other Nonuniform Field Configurations for Applications in Antihydrogen Production." Thesis, University of North Texas, 2016. https://digital.library.unt.edu/ark:/67531/metadc849779/.
Full textHessmo, Björn. "Quantum optics in constrained geometries." Doctoral thesis, Uppsala University, Department of Quantum Chemistry, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-1208.
Full textWhen light exhibits particle properties, and when matter exhibits wave properties quantum mechanics is needed to describe physical phenomena.
A two-photon source produces nonmaximally entangled photon pairs when the source is small enough to diffract light. It is shown that diffraction degrades the entanglement. Quantum states produced in this way are used to probe the complementarity between path information and interference in Young's double slit experiment.
When two photons have a nonmaximally entangled polarization it is shown that the Pancharatnam phase is dependent on the entanglement in a nontrivial way. This could be used for implementing simple quantum logical circuits.
Magnetic traps are capable of holding cold neutral atoms. It is shown that magnetic traps and guides can be generated by thin wires etched on a surface using standard nanofabrication technology. These atom chips can hold and manipulate atoms located a few microns above the surface with very high accuracy. The potentials are very versatile and allows for highly complex designs, one such design implemented here is a beam splitter for neutral atoms. Interferometry with these confined de Broglie is also considered. These atom chips could be used for implementing quantum logical circuits.
Webster, Stephen. "Prospects for Bose-Einstein condensation in caesium : cold collisions and dipole-force trapping." Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325563.
Full textHaigh, Tania J. "Bose-Einstein condensates in coupled co-planar double-ring traps : a thesis presented in partial fulfillment of the requirements for the degree of Masterate of Science in Physics at Massey University, Palmerston North, New Zealand." Massey University, 2008. http://hdl.handle.net/10179/975.
Full textCruz-Cruz, Luis R. "Electronic and magnetic properties of trans-polyacetylene." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/28057.
Full textLunney, Matthew David Norwood. "The phase space volume of ion clouds in Paul traps." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=39462.
Full textIon cloud temperatures were measured for seven different trap loadings of potassium ions and four loadings of sodium ions, in both cases down to clouds of about 1000 ions. This is the first time that temperature measurements have been made for such small numbers of buffer-gas cooled ions. The results show that the temperature of the ions above the buffer gas temperature appears to be proportional to the two-thirds power of the number of ions in the cloud.
Dynamic manipulation of the extracted ion cloud phase space volume was also accomplished using a time-varying acceleration voltage to change the ion cloud energy spread in flight.
A concept is also outlined to measure the detailed phase space area of the extracted cloud using the projection-slice theorem of tomographic imaging.
These measurements have applications for the use of ion traps as beam collectors for nuclear physics experiments at isotope separator facilities and possibly for nano-circuit fabrication.
Gallet, Yves. "La magnetostratigraphie : aspects fondamentaux et appliques." Paris 7, 1988. http://www.theses.fr/1988PA077056.
Full textDieckmann, Kai. "Bose-Einstein condensation with high atom number in a deep magnetic trap." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2001. http://dare.uva.nl/document/58167.
Full textThomas, Angharad Mair. "Ultra-cold collisions and evaporative cooling of caesium in a magnetic trap." Thesis, University of Oxford, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.403426.
Full textJackson, Jarom Silver. "In Situ Magnetic Field Characterization with the Directional Hanle Effect." BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/5982.
Full textBerger, T., J. Konheiser, A. V. Anikeev, V. V. Prikhodko, P. A. Bagryansky, E. Yu Kolesnikov, E. I. Soldatkina, Yu A. Tsidulko, K. Noack, and A. A. Lizunov. "Study of high temperature and high density plasmoids in axially symmetrical magnetic fields." Forschungszentrum Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-27870.
Full textGao, Lei. "Determination of quantitative nutritional labeling compositional data of lipids by Nuclear Magnetic Resonance (NMR) spectroscopy." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=111577.
Full textHoogerheide, Shannon Michelle Fogwell. "Trapped positrons for high-precision magnetic moment measurements." Thesis, Harvard University, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3566927.
Full textA single electron in a quantum cyclotron provides the most precise measurement of the electron magnetic moment, given in units of the Bohr magneton by g/2 = 1.001 159 652 180 73 (28) [0.28 ppt]. The most precise determination of the fine structure constant comes from combining this measurement with Standard Model theory, yielding α-1 = 137.035 999 173 (34) [0.25 ppb], limited by the experimental uncertainty of the electron g-value. The most stringent test of CPT symmetry in leptons comes from comparing the electron and positron magnetic moments, limited by the positron uncertainty at 4.2 ppt. A new high-stability apparatus has been built and commissioned for improved measurements of the electron and positron magnetic moments, a greatly improved test of lepton CPT symmetry, and an improved determination of the fine structure constant. These new measurements require robust positron loading from a retractable radioactive source that is small enough to avoid compromising the high-precision environment of our experiment. The design and implementation of such a scheme is a central focus of this work. Robust positron loading at a rate of 1-2 e+/min from a 6.5 μCi 22Na source has been demonstrated.
Davey, Louise. "Mass selective capture by an RFQ trap of externally injected ions." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60660.
Full textAn Paul trap and associated electronics have been assembled and tested, selectively trapping the ionic clusters C$ sp{+} sb2$ and C$ sp{+} sb3$ from a pulsed laser ion source. The ions were injected at 90 eV, trapped, extracted and detected, several parameters related to these processes were investigated. Simple models of the injection mechanism employed and for evaluating the pseudo-potential well depth of the ion trap are proposed. The overall efficiency of the ion injection system has been evaluated and compared to other methods of ion capture by an RFQ trap from an external source.
Berger, T., J. Konheiser, A. V. Anikeev, V. V. Prikhodko, P. A. Bagryansky, E. Yu Kolesnikov, E. I. Soldatkina, Yu A. Tsidulko, K. Noack, and A. A. Lizunov. "Study of high temperature and high density plasmoids in axially symmetrical magnetic fields." Forschungszentrum Dresden-Rossendorf, 2009. https://hzdr.qucosa.de/id/qucosa%3A21614.
Full textCollins, Sean Michael 1959. "Electrode material and geometry effects on the electrical properties of particle traps in a parallel plate plasma etch reactor." Thesis, The University of Arizona, 1993. http://hdl.handle.net/10150/278287.
Full textStacey, John-Patrick. "Stabilization and control in a linear ion trap." Thesis, University of Oxford, 2003. http://ora.ox.ac.uk/objects/uuid:5c019c02-c313-4fb4-92f4-8a342dd5dbf6.
Full textSahelgozin, Maral [Verfasser]. "Design and construction of a transportable quantum gravimeter and realization of an atom-chip magnetic trap / Maral Sahelgozin." Hannover : Gottfried Wilhelm Leibniz Universität Hannover, 2019. http://d-nb.info/1190283417/34.
Full textHenn, Emanuel Alves de Lima. "Variação da temperatura cinética em átomos aprisionados bombeados por campos externos." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/76/76131/tde-06062007-183559/.
Full textIn this work we present a study of the shift of the kinetic temperature of magnetically trapped atoms, excited by external electromagnetic fields. We trapped Sodium atoms in a quadrupole magnetic trap and applied an oscilating magnetic field to these atoms. We mesured the temperature and the number of the remaining atoms from time of flight images. The measure is done turning off the trap, leaving the cloud of atoms in a ballistic expansion and making an image of the fluorescence of these atoms after the shot of a near ressonant light. From the size of the cloud and the number of photons captured we can measure the temperature and number of atoms in the sample. We observed cooling of the atoms for some frequencies of the external field and heating for frequencies a bit larger. We observed that a high number of atoms were lost from the trap simultaneously with the cooling. Finally, we present numerical simulations that reproduce the observed phenomena and a model that explains the experiments\' results based on selective excitation of the trapped atoms by the external field.
Dobson, Laura Elizabeth. "Cardiovascular magnetic resonance imaging in severe aortic stenosis : impact of surgical and trans-catheter aortic valve replacement on reverse remodelling and fibrosis." Thesis, University of Leeds, 2016. http://etheses.whiterose.ac.uk/12944/.
Full textRosenau, Felix. "HOPE - un piège magnétique pour neutron ultra-froid dédié à la mesure du temps de vie du neutron : conception et premières données expérimentales." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAY036/document.
Full textThe lifetime of the free neutron plays an important role in fundamental particle physics as well as cosmological models. Our knowledge of the precise value of the neutron lifetime is limited by the systematical inaccuracies of the two commonly used experimental approaches, the so called “beam” and “material bottle” methods. Moreover a systematic deviation of the lifetime-values extracted from both methods has become manifest over the past decades.The HOPE project is part of a new generation of experiments that aims to determine the neutron lifetime by storing ultra cold neutrons (UCN) in a combined magneto-gravitational potential. HOPE generates the necessary gradient magnet fields by a combination of highly potent rare-earth permanent magnets with a maximum B-field strength of about 1.3 T and a set of superconducting coils. In this thesis I give a detailed description of the apparatus, possible systematical effects and how we are planning to investigate and cope with those effects. Subsequently the results from a first beamtime at the PF2 source will be presented and discussed. The results are encouraging as we reached a maximum storage-time constants of 881(46) s, indicating a very small UCN loss rate during storage
Laidler, Christopher I. "Application of microwave sidebands from an optically injected diode laser to atomic physics and the construction of a magnetic trap for neutral atoms." Thesis, Swansea University, 2013. https://cronfa.swan.ac.uk/Record/cronfa42839.
Full textMagalhães, Kilvia Mayre Farias. "Obtenção da degenerescência quântica em sódio aprisionado." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-24012008-083710/.
Full textUsing a system composed of a QUIC trap loaded from a slowed atomic beam, we have performed experiments to observe the Bose-Einstein Condensation of Na atoms. In order to obtain the atomic distribution in the trap, we use an in situ out of resonance absorption image of a probe beam to determine the temperature and the density, which are use to calculate the phase space D. We have followed D as a function of the final evaporation frequency. The results show that at 1.65 MHz we crossed the critical value for D which corresponds to the point to start Bose-Condensation of the sample. Due to the low number of atoms remaining in the trap at the critical point, the interaction produce minor effects and therefore an ideal gas model explains well the observations.
Wiesel, Marco [Verfasser], Gerhard [Akademischer Betreuer] Birkl, and Wolfgang [Akademischer Betreuer] Quint. "Preparation and Investigation of Highly Charged Ions in a Penning Trap for the Determination of Atomic Magnetic Moments / Marco Wiesel ; Gerhard Birkl, Wolfgang Quint." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2017. http://d-nb.info/1136078711/34.
Full textGuégan, Frédéric. "Joint experimental and theoretical approaches in coordination chemistry : from the trans effects to Single Molecule Magnets." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1267/document.
Full textIn this work, we focused on the description and rationalisation of certain properties of coordination complexes through the use of joint experiment/theory approaches. The first study is purely theoretical, and revisits the coordination properties of ligands using conceptual DFT methods. In a first time, ligands alone are studied, and the results of this study are then employed to characterise and rationaliser the trans effects in octahedral complexes. The second study deals with the syntheses and characterisation of polynuclear Cu(II) complexes deriving from amino-acid based Schiff base-like ligands. In a first time, the reactivity of these complexes in solution is rationalised through the use of spectroscopies and DFT calculations. Then, the magnetic properties of two trinuclear complexes are presented and analysed thanks to high level ab initio calculations. Finally, in the third study we focus on mononuclear lanthanide-based complexes presenting a slow dynamics of magnetisation at low temperature. Magnetic measurements, as well as luminescence and polarised neutron diffraction experiments, combined to SA-CASSCF/RASSI-SO calculation allow the rationalisation of the observed magnetic properties
Naik, Devang S. "Bose-Einstein Condensation: Building the Testbeds to Study Superfluidity." Diss., Available online, Georgia Institute of Technology, 2006, 2006. http://etd.gatech.edu/theses/available/etd-09072006-141453/.
Full textDavidovic, Dragomir, Committee Member ; Kennedy, T.A. Brian, Committee Member ; Chapman, Mike, Committee Member ; Raman, Chandra, Committee Chair ; Bunz, Uwe, Committee Member.
Bera, Manabendra Nath. "Zeeman Deceleration of Supersonic Beam trapping of Paramagnetic Atoms in a Traveling Magnetic Wave." Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00599318.
Full textLeung, Kent [Verfasser], Peter [Akademischer Betreuer] Fierlinger, and PETER [Akademischer Betreuer] BOENI. "Development of a new superfluid helium ultra-cold neutron source and a new magnetic trap for neutron lifetime measurements / Kent Leung. Gutachter: Peter Fierlinger ; Peter Böni. Betreuer: Peter Fierlinger." München : Universitätsbibliothek der TU München, 2013. http://d-nb.info/1031511776/34.
Full textLindenfels, David-Friedrich von [Verfasser], and Wolfgang [Akademischer Betreuer] Quint. "Experimental Studies of Highly Charged Ions in a Penning Trap for the Measurement of Electron Magnetic Moments by Double-Resonance Spectroscopy / David-Friedrich Freiherr von Lindenfels ; Betreuer: Wolfgang Quint." Heidelberg : Universitätsbibliothek Heidelberg, 2015. http://d-nb.info/1180502809/34.
Full textLeung, Kent Kwan Ho [Verfasser], Peter [Akademischer Betreuer] Fierlinger, and PETER [Akademischer Betreuer] BOENI. "Development of a new superfluid helium ultra-cold neutron source and a new magnetic trap for neutron lifetime measurements / Kent Leung. Gutachter: Peter Fierlinger ; Peter Böni. Betreuer: Peter Fierlinger." München : Universitätsbibliothek der TU München, 2013. http://nbn-resolving.de/urn:nbn:de:bvb:91-diss-20130213-1119646-0-0.
Full textCorrêa, Thiago Reginaldo. "Implicações do uso de campos magnéticos oscilantes em um mot de rubídio." Universidade do Estado de Santa Catarina, 2012. http://tede.udesc.br/handle/handle/1969.
Full textCoordenação de Aperfeiçoamento de Pessoal de Nível Superior
This work presents a study about infuences that a quadripolar magnetic field periodically time dependent, can promote in a magneto-optical trap (MOT). The intention reflects the interest in finding an oscillating field configuration that enables the capture and provide benefits if compared to the typical process of trapping. In many papers that will be cited here, a MOT uses a magnetic field that promotes a linear steady magnetic field gradient from the center of the trap. Applying experimental results involving magnetic field oscillations, which will be quoted in detail throughout this text, came the initiative to mathematically model the problem and seek a form of oscillation that may result in a more efficient trapping. Numerical results in a one-dimensional model suggests that the number of atoms is strongly aflected by fuctuations, but we have not found, for the modulations suggests in this work, an oscillation model that could provide an increase of the trap atoms. It was noted that the oscillation frequency of the atom is subjected, aflect the amplitude of the oscillations in the number of trapped atoms.
Neste trabalho apresentamos um estudo sobre as influências que um campo quadripolar magnético, periodicamente dependente do tempo, pode promover em uma armadilha magnético-óptica (Magneto Optical Trap - MOT). O objetivo deste trabalho reflete o interesse em encontrar uma configuração de campo oscilante que possibilite o aprisionamento e forneça vantagens em relação ao processo típico de armadilhamento. Em muitos dos trabalhos que serão citados aqui, um MOT utiliza um campo magnético quadripolar estacionário que promove um gradiente de campo magnético linear à partir do centro da armadilha. Usando resultados experimentais envolvendo oscilações no campo magnético, que serão citados mais detalhadamente no decorrer deste texto, surgiu a iniciativa de modelar o problema matematicamente e buscar uma forma de oscilação que possa resultar em um aprisionamento mais eficiente. Resultados numéricos concebidos em um modelo unidimensional sugerem que o número de átomos é fortemente afetado pelas oscilações, mas não foi possível encontrar, para as modulações sugeridas neste trabalho, uma modulação que pudesse fornecer aumento expressivo no número de átomos armadilhados. Foi possível constatar que a freqüência da oscilação a que o átomo é submetido, afetará a amplitude das oscilações no número de átomos armadilhados.
Alcantara, Katianne Fernandes de. "Simulação de resfriamento a laser em armadilha magnética e construção de laser de cavidade estentida." Universidade do Estado de Santa Catarina, 2010. http://tede.udesc.br/handle/handle/2002.
Full textCoordenação de Aperfeiçoamento de Pessoal de Nível Superior
Laser cooling in high magnetic fields, presents a series of difficulties due to inhomogeneous broadening of the frequency due to Zeeman Effect. In the first part of this work we investigate the laser cooling of Li by a Monte Carlo simulation, the 2S(1/2)-> 2P(3/2) transition at 670.96 nm in a magnetic trap under the characteristics of trap operating at the LASER laboratory of the Institute of Physics, UFRJ. In the second part, we built a diode laser with extended Littrow cavity emitting in 972 nm using the configuration of extended cavity Littrow. The purpose of this laser is, after a double frequency doubling, to use it to study the hydrogen atom in the transition 1S -> 2S at 243 nm.
O resfriamento a laser em altos campos magnéticos, apresenta uma série de dificuldades devido ao alargamento inomogêneo da transição causado pelo efeito Zeeman. Na primeira parte desse trabalho investigamos o resfriamento a laser de Lítio através de uma simulação de Monte Carlo, na transição 2S1/2 -> 2P3/2 em 670.96 nm, em uma armadilha magnética com as características da armadilha em funcionamento no laboratório LASER do instituto de Física da UFRJ. Na segunda parte, foi construído um laser de diodo em cavidade estendida emitindo em 972 nm utilizando a configuração de Cavidade Estendida de Littrow. O propósito desse laser e após um duplo dobramento de freqüência, utilizá-lo para estudo do átomo de Hidrogênio na transição 1S -> 2S em 243 nm.
Gutiérrez, Gimeno Manuel. "Análisis de nuevas estrategias cardioprotectoras destinadas a modular el remodelado ventricular tras infarto agudo de miocardio: estudio preclínico y seguimiento mediante técnicas de imagen no invasiva de alta resolución." Doctoral thesis, Universitat Autònoma de Barcelona, 2019. http://hdl.handle.net/10803/669462.
Full textIntroduction: ischemic heart disease is one of the leading causes of morbidity and mortality worldwide. A sharp decline in the mortality rate of patients suffering from acute myocardial infarction has been achieved, at the cost of rising cases of chronic heart failure. In consequence, it is necessary to devise new therapeutic approaches to prevent cardiac remodeling and the ensuing heart failure. In this regard, cardioprotection appears as a foreseeable mainstay. We now know the total necrotic area derives from a combination of the ischemic injury and an added damage produced by the sudden restoration of blood flow in the obstructed coronary artery’s territory, the reperfusion injury. Reperfusion injury plays a key role in the development of cardiac remodeling and chronic heart failure. P2Y12 blockers are a group of antiplatelet agents that are standard care in the setting of acute myocardial infarction. However, within the group there are different subtypes with different pharmacokinetic and pharmacodynamic profiles (e.g., the standard of care clopidogrel and the new generation P2Y12 receptor blocker ticagrelor). Ticagrelor is believed to have effects on adenosine metabolism, molecule with cardioprotective implications. In this thesis we mean to prove that ticagrelor exerts a higher cardioprotective impact as compared to clopidogrel on the infarcted heart, independently of their antiplatelet effect. Material and methods: we designed an animal (swine) myocardial infarction model composed by two studies with a common layout. Animals were randomly allocated to equally sized groups receiving different interventions (placebo, clopidogrel and ticagrelor). An infarction was induced in all animals after the initial loading dose and, in the following days, they were brought to a magnetic resonance (MR) facility where functional and structural cardiac parameters were studied. Global and segmental motility as well as cardiac oedema, microvascular obstruction and late necrosis were assessed. Finally, the animals were sacrificed and their heart sliced to perform histologic and molecular analysis that assessed the expression and activation of molecules related to oedema formation and cell survival (i.e. aquaporin-4, AMPK molecules). Whereas the first study was centred in the effects in the first 24h after myocardial infarction, the second study was intended for evaluation of the chronic effects (3d and 42d after MI). Results: The use of any antiplatelet agent reduces myocardial damage as compared to placebo (less myocardial oedema and necrosis, better functional parameters in MR). However, ticagrelor does so to a greater extent than clopidogrel. The observed reduction is statistically significant in both oedema and necrosis and concurs with the results of molecular analyses. The expression of acuaporine-4 is reduced and the expression and activation of AMPK increased in animals treated with ticagrelor. Acuaporine-4 is a channel transporter that eases the entrance of water in the cell under stress conditions. On the other hand, AMPK acts by diminishing extracellular oedema and promoting cell survival. Ticagrelor also shows a positive impact on functional parameters in both, acute and chronic phases after myocardial infarction. Left ventricle ejection fraction as well as regional wall motion are less impaired in animals treated with ticagrelor than clopidogrel at day 3 and day 42. Remarkably, all the positive effects described with ticagrelor are reversed when an adenosine receptor blocker is added. This fact shows the cardioprotective potential of ticagrelor is mediated by adenosine. Conclusion: In this thesis we demonstrate ticagrelor, a new generation of P2Y12 inhibitor, shows additional cardioprotective effects as compared to clopidogrel and that these effects are mediated by adenosine. The positive impact is observed in the acute and chronic phases after myocardial infarction and is present in both, structural and functional parameters.
Meerkin, Jarrod D. "Musculo-skeletal adaptation and altered loading environments: An amputee model." Thesis, Queensland University of Technology, 2000. https://eprints.qut.edu.au/36750/1/36750_Digitised%20Thesis.pdf.
Full textRodríguez, Palomares José Fernando. "Cambios dinámicos del tamaño del infarto y la obstrucción de la microcirculación tras administración de constraste mediante cardio-resonancia magnética y su valor pronóstico en el remodelado ventricular izquierdo." Doctoral thesis, Universitat Autònoma de Barcelona, 2016. http://hdl.handle.net/10803/382827.
Full textBackground: In acute myocardial infarction (MI), late Gadolinium enhancement (LGE) has been proposed to include the infarcted myocardium and area at risk. However, little information is available on the optimal timing after contrast injection to differentiate these 2 areas. Also, the role of infarct size on left ventricular (LV) remodeling in heart failure after an acute ST-segment elevation myocardial infarction (STEMI) is well recognized. Infarct size, as determined by cardiovascular magnetic resonance (CMR), decreases over time following a healing process. The amount, rate, and duration of infarct healing are unknown. Our aim was to determine in acute and chronic MI whether imaging time after contrast injection influences the LGE size that better predicts infarct size and functional recovery. Methods: Subjects were evaluated by cardiovascular magnetic resonance (CMR) the first week (n = 60), 3 months and 12 months after a percutaneously revascularized STEMI. Inversion-recovery single-shot (ss-IR) imaging was acquired at multiple time points following contrast administration and compared to segmented inversion-recovery (seg-IR) sequences. Inversion time was properly adjusted and images were blinded, randomized and measured for LGE volumes. Results: In acute MI, LGE volume decreased over several minutes (p = 0.005) with the greatest volume occurring at 3 minutes and the smallest at 25 minutes post-contrast injection; however, LGE volume remained constant over time in chronic MI (p = 0.886). Depending on the imaging time, in acute phase, a change in the transmurality index was also observed. A transmural infarction (>75%) at 25 minutes better predicted the absence of improvement in the wall motion score index (WMSI), a higher increase in left ventricular volumes and a lower ejection fraction compared to 10 minutes. Mean infarct sizes at baseline (acute necrosis), early follow-up (early scar), and late follow-up (late scar) were 25 ± 17 g, 17 ± 12 g, and 15 ± 11 g, respectively. Patients were stratified in tertiles, based on infarct size, with the largest infarcts having the greatest absolute decrease in mass at early and late scar. The percent reduction of infarct mass was independent of initial infarct size. There was an 8 g or 32% decrease in infarct mass between acute necrosis and early scar (p < 0.01) with a 2 g or 12% additional decrease in infarct mass between early and late scar (p < 0.01). Conclusions: A change was observed in LGE volume in the minutes following contrast administration in acute but not in chronic MI. Infarct transmurality 25 minutes post-contrast injection better predicted infarct size and functional recovery at follow-up. Also, we observed that infarct healing is a continuous process after reperfusion for STEMI, with greatest reduction in infarct size in the first few months. The dynamic nature of infarct healing through the first year after STEMI indicates that decisions based on infarct size, and interventions to reduce infarct size, must take into consideration the time frame of measurement.
Lewoczko-Adamczyk, Wojciech. "Bose-Einstein condensation in microgravity." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2009. http://dx.doi.org/10.18452/15970.
Full textRecently, cooling, trapping and manipulation of neutral atoms and ions has become an especially active field of quantum physics. The main motivation for the cooling is to reduce motional effects in high precision measurements including spectroscopy, atomic clocks and matter interferometry. The spectrum of applications of these quantum devices cover a broad area from geodesy, through metrology up to addressing the fundamental questions in physics, as for instance testing the Einstein’s equivalence principle. However, the unprecedented precision of the quantum sensors is limited in terrestial laboratories. Freezing atomic motion can be nowadays put to the limit at which gravity becomes a major perturbation in a system. Gravity can significantly affect and disturb the trapping potential. This limits the use of ultra-shallow traps for low energetic particles. Moreover, free particles are accelerated by gravitational force, which substantially limits the observation time. Targeting the long-term goal of studying cold quantum gases on a space platform, we currently focus on the implementation of a Bose-Einstein condensate (BEC) experiment under microgravity conditions at the drop tower in Bremen. Special challenges in the construction of the experimental setup are posed by a low volume of the drop capsule as well as critical decelerations up to 50g during recapture at the bottom of the tower. All mechanical and electronic components were thus been designed with stringent demands on miniaturization and mechanical stability. This work reports on the observation of a BEC released from an ultra-shallow magnetic potential and freely expanding for one second. Both, the low trapping frequency and long expansion time are not achievable in any earthbound laboratory. This unprecedented time of free evolution leads to new possibilities for the study of BEC-coherence. It can also be applied to enhance the sensitivity of inertial quantum sensors based on ultra-cold matter waves.
Tan, Yi Lei. "Structural and Biophysical Characterisation of Denatured States and Reversible Unfolding of Sensory Rhodopsin II." Thesis, University of Cambridge, 2019. https://www.repository.cam.ac.uk/handle/1810/289718.
Full textBrahimi, Sonia. "Caractérisation géophysique (méthodes potentielles, imagerie sismique) de structures géologiques : des terranes panafricains de la chaine trans-saharienne, aux vallées-tunnel et incisions glaciaires de la Mer du Nord et d'Algérie." Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAH005.
Full textThe magnetic and gravimetric data analysis of the northern part of the trans-saharan belt allowed to propose a geophysical and rheological compartmentalization map of its crustal structures and to visualize the Tuareg shield terranes over 1000 km to the north, under the saharan sedimentary basins and several aspects have been discussed. A pseudo network of four successive generations of paleovalleys and incisions has been identified on the upper Ordovician glacial succession in the north-eastern part of the Illizi basin on the basis of high-resolution seismic data. For each incision, the geometry and seismic facies of their filling have been determined. Parallelism between the distribution of some paleovalleys and magnetic anomaly orientations has been observed, but no stratigraphic relationship between them has been identified on seismic sections. A complex network of Pleistocene glacial tunnel valleys in the North Sea has been identified on the basis of high-resolution aeromagnetic data. A detailed magnetic analysis was performed by combining several magnetic methods. Finally, 2D synthetic magnetic models were calculated for Ordovician incisions, applied in the case of the Illizi basin. The results obtained show that their magnetic detection is possible, if a high-resolution magnetic survey would still be available