Tesis sobre el tema "Dose secondaire"
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Bonfrate, Anthony. "Développement d'un modèle analytique dédié au calcul des doses secondaires neutroniques aux organes sains des patients en protonthérapie". Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS408/document.
Texto completoStray neutron doses are currently not evaluated during treatment planning within proton therapy centers since treatment planning systems (TPS) do not allow this feature while Monte Carlo (MC) simulations and measurements are unsuitable for routine practice. The PhD aims at developing an analytical model dedicated to the estimation of stray neutron doses to healthy organs which remains easy-to-use in clinical routine. First, the existing MCNPX model of the gantry installed at the Curie institute - proton therapy center of Orsay (CPO) was extended to three additional treatment configurations (energy at the beam line entrance of 162, 192 and 220 MeV). Then, the comparison of simulations and measurements was carried out to verify the ability of the MC model to reproduce primary proton dose distributions (in depth and lateral) as well as the stray neutron field. Errors within 2 mm were observed for primary protons. For stray neutrons, simulations overestimated measurements by up to a factor of ~2 and ~6 for spectrometry and dose equivalent in a solid phantom, respectively. The result analysis enabled to identify the source of these errors and to put into perspective new studies in order to improve both experimental measurements and MC simulations. Secondly, MC simulations were used to calculate neutron doses to healthy organs of a one-year-old, a ten-year-old and an adult voxelized phantoms, treated for a carniopharyngioma. Treatment parameters were individually varied to study their respective influence on neutron doses. Parameters in decreasing order of influence are: beam incidence, organ-to-collimator and organ-to-treatment field distances, patient’ size/age, treatment energy, modulation width, collimator aperture, etc. Based on these calculations, recommendations were given to reduce neutron doses. Thirdly, an analytical model was developed complying with a use in clinical routine, for all tumor localizations and proton therapy facilities. The model was trained to reproduce calculated neutron doses to healthy organs and showed errors within ~30% and ~60 µGy Gy⁻¹ between learning data and predicted values; this was separately done for each beam incidence. Next, the analytical model was validated against neutron dose calculations not considered during the training step. Overall, satisfactory errors were observed within ~30% and ~100 µGy Gy⁻¹. This highlighted the flexibility and reliability of the analytical model. Finally, the training of the analytical model made using neutron dose equivalent measured in a solid phantom at the center Antoine Lacassagne confirmed its universality while also indicating that additional modifications are required to enhance its accuracy
Bessières, Igor. "Développement et validation expérimentale d'un outil de détermination de la dose hors-champ en radiothérapie". Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-00801314.
Texto completoBessières, Igor. "Développement et validation expérimentale d’un outil de détermination de la dose hors-champ en radiothérapie". Thesis, Paris 11, 2013. http://www.theses.fr/2013PA112016/document.
Texto completoOver the last two decades, many technical developments have been achieved on intensity modulated radiotherapy (IMRT) and allow a better conformation of the dose to the tumor and consequently increase the success of cancer treatments. These techniques often reduce the dose to organs at risk close to the target volume; nevertheless they increase peripheral dose levels. In this situation, the rising of the survival rate also increases the probability of secondary effects expression caused by peripheral dose deposition (second cancers for instance). Nowadays, the peripheral dose is not taken into account during the treatment planification and no reliable prediction tool exists. However it becomes crucial to consider the peripheral dose during the planification, especially for pediatric cases. Many steps of the development of an accurate and fast Monte Carlo out-of-field dose prediction tool based on the PENELOPE code have been achieved during this PhD work. To this end, we demonstrated the ability of the PENELOPE code to estimate the peripheral dose by comparing its results with reference measurements performed on two experimental configurations (metrological and pre-clinical). During this experimental work, we defined a protocol for low doses measurement with OSL dosimeters. In parallel, we highlighted the slow convergence of the code for clinical use. Consequently, we accelerated the code by implementing a new variance reduction technique called pseudo-deterministic transport which is specifically with the objective of improving calculations in areas far away from the beam. This step improved the efficiency of the peripheral doses estimation in both validation configurations (by a factor of 20) in order to reach reasonable computing times for clinical application. Optimization works must be realized in order improve the convergence of our tool and consider a final clinical use
Ronga, Maria Grazia. "Study and modelling of very high energy electrons (VHEE) radiation therapy". Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPAST036.
Texto completoThe development of innovative methods capable of reducing the sensitivity of healthy tissue to radiation, while maintaining the effectiveness of the treatment on the tumour, is a central aspect of improving the effectiveness of radiotherapy in the treatment of cancer. Among possible developments and methodological innovations, the combination of ultra-high dose rate irradiation (FLASH) and very high energy electrons (VHEE) could make it possible to exploit the radiobiological advantages of the FLASH effect for the treatment of deep tumours. In particular, VHEEs in the 100 to 250 MeV energy range would be particularly interesting from a ballistic and biological point of view for the application of FLASH irradiation in radiotherapy. This thesis therefore studies the possible use of VHEEs in radiotherapy, and in particular their use at ultra-high dose rates, thus assessing the feasibility of FLASH-VHEE radiotherapy. Although promising, several aspects of this technique need to be studied before it can be used in a clinical context. The first part of this work studies the machine parameters required to meet the constraints of FLASH irradiation. To this end, an analytical model for calculating the dose based on Fermi-Eyges multiple scattering theory was developed and tested. This analytical model has also been used to design and optimise a double-scattering system for VHEE therapy, in order to obtain field sizes greater than 15x15 cm², and to assess the possible adaptation of conventional particle beam conformation methods for FLASH-VHEE therapy. The second part of this work focuses on VHEE treatment planning and the evaluation of clinical plans. Four representative clinical cases were studied, for which pencil-beam scanning (PBS) and double scattering (DS) treatment plans were calculated. The influence of beam energy on plan quality was studied and the PBS and DS techniques were compared. A temporal description of the irradiation was also carried out, as well as the incorporation of a FLASH modification factor when evaluating the plan and its effect on healthy tissue in FLASH mode. Finally, the estimation of doses from secondary particles and radiation protection issues were addressed. A calculation of the secondary dose due to Bremsstrahlung photons and neutrons from the two dose delivery systems was developed in water. The secondary particle dose received by various organs was also assessed in the context of intracranial treatments and in order to demonstrate the advantage of VHEE beams over proton beams in terms of out-of-field neutron dose. In summary, the fast analytical models parameterised in this study allow the dose distribution produced by a VHEE system to be estimated with good accuracy, providing important information for the potential design of a VHEE system. The results of this work could support the development of FLASH-VHEE radiotherapy
Hourcade-Potelleret, Florence. "De la dose à l'effet clinique : utilisation de la modélisation dans les différentes étapes du processus de prédiction du critère clinique : Exemple avec un nouveau médicament en prévention secondaire de la morbidité-mortalité cardiovasculaire". Phd thesis, Université Jean Monnet - Saint-Etienne, 2012. http://tel.archives-ouvertes.fr/tel-00979667.
Texto completoRyckman, Jeffrey M. "Using MCNPX to calculate primary and secondary dose in proton therapy". Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/39499.
Texto completoFricker, Katherine. "Collateral exposure: the additional dose from radiation treatment". Thesis, University of Canterbury. Physics and Astronomy, 2012. http://hdl.handle.net/10092/10361.
Texto completoLeitão, João Luís Vieira. "Climate changes: effects of secondary salinisation in freshwater organisms". Master's thesis, Universidade de Aveiro, 2011. http://hdl.handle.net/10773/8332.
Texto completoAs global climate patterns change, so will freshwater availability. Specially, salinisation of freshwater costal ecosystem is a major point of concern; either by surface flooding or by groundwater intrusions of seawater. This may be potentiated by the decrease of freshwater availability provoked by longer drought periods, evaporation, and increased freshwater extraction (for example for agriculture and other human uses). According, the present work aimed at evaluating how freshwater organisms responded to an increase in salinity. To achieve this main objective two specific goals were delineated: (i) to compare the toxicity of seawater with a surrogate (NaCl), commonly used in laboratory toxicity assays, to two standard freshwater species, and (ii) to assess if an association exist between resistance to chemical contamination and to increased salinity; since many populations, predicted to experience future increased salinity, are presently exposed to chemical contamination. To accomplish the first objective the sensitivity of the green algae Pseudokirchneriella subcapitata (Korshikov) F. Hindák and of the cladoceran Daphnia magna Straus to NaCl and to natural seawater was evaluated. Growth rate for P. subcapitata, and mortality, time to release the first brood, body size, total reproduction, and intrinsic rate of natural increase for D. magna, were monitored after exposing these species to two series of solutions with an increasing gradient of salinity. One series of solutions was established with a natural seawater sample and the other with NaCl dissolved artificial media. To address the second objective, four cloned lineages of Daphnia longispina O.F. Müller, exhibiting different sensitivities to lethal levels of copper, were exposed to a gradient of lethal and sublethal levels of salinity, established with the salt NaCl. The same endpoins described for D. magna were also monitored for D. longispina. The obtained results showed that NaCl exerted a higher toxicity to P. subcapitata (LOEC of 5.9mS/cm and 9.6mS/cm, respectively for NaCl and seawater) and to D. magna (LC50,48h of 9.88mS/cm and 11.32mS/cm; and EC50 for total reproduction of 8.9mS/cm and 10.4mS/cm, respectively for NaCl and seawater) than the natural seawater. These data suggest that the use of NaCl as a surrogate for seawater to predict, in laboratory, the effects of seawater intrusion in freshwater is a protective approach as it simulates a “Worst Case Scenario” of exposure. An association between resistance to copper and to NaCl was not observed for the tested cloned lineages of D. longispina (r < 0.92 and p > 0.08), though the two clonal lineages most resistant to copper also exhibited the highest sensitivity to sublethal levels of NaCl (determined as the EC20 for total reproduction). Finally, obtained data demonstrated that D. longispina was more sensitive to increased salinity (LC50,48h of 2.85g/L to 2.48g/L or, conductivity values of LC50,48h of 5.50mS/cm to LC50,48h= 4.57mS/cm which correspond respectively to the highest and lowest recorded values in these assays) than the standard species (D. magna), highlighting the importance of using autochthonous species for the ecological risk assessment of secondary salinisation.
À medida que os padrões climáticos se alteram também a disponibilidade de água doce se irá alterar. Como tal, a salinização de ecossistemas costeiros, principalmente os dulçaquicolas, torna-se um ponto de preocupação fundamental. Quer devido ao aumento de intrusões de água do mar por inundação ou por intrusões salinas através dos lençóis freáticos, quer devido à diminuição de entrada de água doce, provocada por períodos mais prolongados de seca, evaporação e aumento do uso de água para actividades antropogénicas. De acordo com o exposto, o presente trabalho pretendeu avaliar as respostas de organismos dulçaquicolas a alterações provocadas pelo aumento de salinidade. Para atingir este objectivo principal foram delineados dois objectivos específicos: (i) comparar a toxicidade de água do mar com a do sal NaCl, comummente usado em laboratório como substituto de água do mar e (ii) averiguar uma possível correlação entre a resistência a contaminação química (cobre) e a aumento de salinidade; uma vez que muitas das populações que se prevê virem a ser afectadas por salinização estão, presentemente, já expostas a contaminação química. Para abordar o primeiro objectivo, a alga verde Pseudokirchneriella subcapitata (Korshikov) F. Hindák e o cladócero Daphnia magna Straus foram expostos a dois gradientes crescentes de salinidade estabelecidos com água do mar natural e com NaCl dissolvido num meio artificial.. No ensaio com a alga verde unicelular foi avaliada a inibição do crescimento; no ensaio com D. magna foram avaliados os seguintes parâmetros: mortalidade, tempo decorrido até libertar a primeira ninhada, comprimento corporal, reprodução total, taxa de crescimento intrínseco. Para atingir o segundo objectivo, foram seleccionadas quatro linhagens do cladócero Daphnia longispina O.F Müller com sensibilidades diferentes a níveis letais de cobre. As quatro linhagens foram expostas a um gradiente de concentrações, letais e sub-letais, de NaCl. Neste ensaio foram analisados os mesmo parâmetros descritos anteriormente para o ensaio com D. magna. Os resultados demonstram que o sal NaCl apresentou maior toxicidade do que a água do mar natural, quer para P. subcapitata (LOEC de 5.9mS/cm e de 9.6mS/cm, respectivamente para NaCl e água do mar), quer para D. magna (LC50,48h de 9.88mS/cm e LC50,48h= 11.32mS/cm; e EC50, para reprodução total, de 8.9mS/cm e 10.4mS/cm, respectivamente para NaCl e água do mar). Estes dados sugerem que o uso de NaCl, em laboratório, como um substituto de água do mar deve ser considerado como uma abordagem protectora, uma vez que simula um cenário de maior toxicidade. Não foi observada uma associação significativa entre maior resistência a cobre e a NaCl nas linhagens de D. longispina testadas (r < 0.92 and p ≥ 0.08), apesar de as duas linhagens mais resistentes a cobre apresentarem as maiores sensibilidades a níveis subletais (para reprodução total) de NaCl. Finalmente, os dados obtidos demonstram que D. longispina é mais sensível ao aumento de salinidade (o intervalo de valores de LC50,48h calculados foi de 2.85g/l a 2.48g/l de NaCl, correspondente a valores de conductividade de 5.50mS/cm e 4.57mS/cm, respectivamente) que a espécie padrão (D. magna), salientando a importância do uso de espécies autóctones na avaliação de risco ecológico em situações de intrusões salinas.
Jaillet, Cyprien. "Modifications du glycome endothélial vasculaire dans le contexte d'une irradiation à forte dose". Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066021/document.
Texto completoRadiotherapy is one of the main treatments against cancers. However, it presents a risk of adverse effects for the normal tissues surrounding the tumors. The vascular network and especially the endothelium are considered as main targets to limit normal tissue damages and prevent side effects of radiotherapy. Activated endothelial cells are involved in the chronic recruitment of thrombocytes and leukocytes, resulting in tissue complications. On the other hand, in inflammatory diseases, the glycans expressed on the surface of endothelial cells are modified and lead to immune cells recruitment. We sought to evaluate changes in endothelial glycome in a context of exposure to high dose of radiation, and studied the functional consequences on the recruitment of leukocytes. In vitro, the characterization of the glycome was performed on a primary endothelial cell model (HUVEC). Our results provide the first evidences of an endothelial modification of the glycome after exposure to ionizing radiation. We report an overexpression of high mannose N-glycans, O-glycans and syalilated motifs. At the same time, endothelial glycocalyx appeared to be damaged by exposure to radiation. Next, we evaluated these radiation-induced modifications of endothelial glycans on monocyte adhesion. We show that the radiation induced adhesion was mediated by overexpression of high mannose N-glycans. We also investigated changes in glycome in an irradiated mouse model of enteropathy and in resections of patients treated with radiotherapy. In mice, a transcriptomic study suggests changes in glycans following radiation exposure. Collectively, these findings on glycome changes provide a new perspective of the continuum of events leading to normal tissue complications. In the future, the study of the glycome should open new therapeutics opportunities for better management of tissue damages induced by radiation
Borucki, Suzanne Janette. "Parent involvement at the secondary level? It can be done!" CSUSB ScholarWorks, 1998. https://scholarworks.lib.csusb.edu/etd-project/1665.
Texto completoSayah, Rima. "Evaluations des doses dues aux neutrons secondaires reçues par des patients de différents âges traités par protonthérapie pour des tumeurs intracrâniennes". Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00810289.
Texto completoWilson, G. Stuart. "Understanding what needs to be done to improve a school". Thesis, Brunel University, 2003. http://bura.brunel.ac.uk/handle/2438/5525.
Texto completoPeet, Samuel. "Out-of-field dosimetry in contemporary radiation therapy". Thesis, Queensland University of Technology, 2022. https://eprints.qut.edu.au/234916/1/9325565_samuel_peet_thesis.pdf.
Texto completoWedel, Elsa. "Biology in Swedish Upper Secondary School : Does it Contribute to Ecocentrism?" Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-157624.
Texto completoDalmann, Romain. "Etude du mécanisme antalgique du Paracétamol ; région cérébrale et mécanisme mis en jeu". Thesis, Clermont-Ferrand 1, 2015. http://www.theses.fr/2015CLF1MM08/document.
Texto completoParacetamol is since its discovery controversial. Whether with respect to the mechanism of action, its side effects or effectiveness, many studies have been performed, at times contradictory. Sometimes criticized for its limited effectiveness, it has nothing to envy in contrast to other analgesics whose effectiveness are often associated with side effects. Paracetamol has proven itself to relieve low to moderate pain without side effects at therapeutic doses. This makes it drug of choice for pregnant women, infants and children. According to a report by the ANSM of the 30 top-selling active substances in France in 2013, with a total of 1.15 billion boxes, paracetamol largely dominates this ranking as its sales are over 500 million boxes. Thus it has become the analgesic and antipyretic most consumed in the world. Today, the pharmacopoeia of analgesics is outdated; evolution of the therapeutic arsenal for 50 years is limited with few major discoveries reported. This observation leads to the need to reassess research strategies to innovate new and more effective molecules. Until now, the aim was to focus on a few molecules with high therapeutic potential in order to optimize their effectiveness without understanding their mechanisms. Now our interest is to understand the mechanisms and targets of these analgesics in order to develop more comparable molecules while limiting their adverse effects. Based on this strategy, paracetamol is a perfect candidate. Indeed, its mechanism of action is not fully known, but its effectiveness is proven. The aim of this work is to elucidate the mystery surrounding its mechanism of action and discover its targets. The latest studies redefine paracetamol as a metabolic precursor to the origin of an active lipid derivative, called AM404. The latter is synthesized in certain regions of the brain expressing the FAAH enzyme capable of catalyzing this reaction. The mechanism thus put into play shows that paracetamol, via AM404, activates TRPV1 receptors and the central CB1 receptors indirectly to reinforce a central mechanism of pain relief via serotonergic descending pathways. However, the cerebral area concerned and the cellular mechanism involved remain unknown. Behavioral data associated with a functional imaging study unveiled several brain regions potentially involved in the action of paracetamol, including the periaqueductal gray matter. The latter sparked our interest for two reasons: one because it expresses the core triad FAAH/TRPV1/CB1; and two it also represents a crossroad of descending serotonergic pathways. Activation in the periaqueductal gray matter of the TRPV1 and CB1 receptors is adapted to produce an antinociceptive effect dependent on these descendant control systems. This work of this thesis has led to re-affirm that the analgesic action induced by paracetamol involves a supra-spinal mechanism dependent on the FAAH enzyme in pathological conditions. Specifically, we investigated the role of the triad FAAH/TRPV1/CB1 in the periaqueductal gray matter. We found that paracetamol interacted with the cell signaling pathway mGluR5-PLC-DAGL responsible for production of the endocannabinoid 2-AG. This mechanism can explain both the close collaboration between the TRPV1 and CB1 receptors in the analgesic effect of paracetamol and the reinforcing of serotonergic descending pathways. Paracetamol is thus a prodrug whose cerebral action involves a set of complex systems to mediate its analgesic effect. This attractive mechanism opens the track to new painkillers ever more effective with fewer side effects, reflected paracetamol mechanism
Micallef-Roll, Joëlle. "Evaluation des effets psychocomportementaux de doses subanesthésiques de kétamine chez le sujet sain". Aix-Marseille 2, 2002. http://theses.univ-amu.fr.lama.univ-amu.fr/2002AIX20663.pdf.
Texto completoBurrows, Andrea C. "Secondary Teacher and University Partnerships: Does Being in a Partnership Create Teacher Partners?" University of Cincinnati / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1307323122.
Texto completoDupont, Stéphane. "Dose absorbée en surface en conditions d'obliquité dans les faisceaux de photons de haute énergie". Toulouse 3, 1994. http://www.theses.fr/1994TOU30204.
Texto completoDe, Graaf Brandon Michael. "Determining the Effect of Shielding for an Eye Exposed to Secondary Particles Produced by Galactic Cosmic Rays using MCNPX Modeling". University of Cincinnati / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1288379556.
Texto completoEiden, Céline. "Essai de faisabilité du suivi thérapeutique pharmacologique et de l'optimisation des antifongiques azolés récents : voriconazole et posaconazole". Montpellier 1, 2009. http://www.theses.fr/2009MON13508.
Texto completoStitzel, Cody Dee. "Empathetic Responding in Psychopathy Subtypes: Does Gender Equivalence between Offender and Victim Matter?" University of Dayton / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1502088898905774.
Texto completoGuerra, Cátia Carina de Almeida. "Salt effects on growth, nutrient and secondary compound contents of Diplotaxis tenuifolia". Master's thesis, Universidade de Aveiro, 2008. http://hdl.handle.net/10773/915.
Texto completoA salinidade do solo é considerada, a nível mundial, como o principal factor abiótico de stress agrícola. Este facto levou ao desenvolvimento de diversos projectos em tolerância salina com o intuito de melhorar as culturas tradicionais e descobrir novas plantas passíveis de crescer nesses solos. Este trabalho centra-se nas respostas de crescimento de Diplotaxis tenuifolia Lquando cultivada sob condições de stress salino. O conhecimento do grau de tolerância salino desta planta é de grande interesse para a agricultura, uma vez que existem observações da ocorrência natural desta planta em zonas sujeitas a stress salino. As plantas foram cultivadas num gradiente de solução nutritiva com as concentrações de 0, 50, 100, 200 e 300 mM NaCl. Em todosos tratamentos as plantas não só sobreviveram, como cresceram e floriram. No entanto, notaram-se alguns sinais inibitórios de crescimento para os doisvalores de salinidade mais elevados. O peso seco e a área foliar foram medidos e a o crescimento relativo (RGR), bem como os seus componentes,rácio foliar unitário (Unit Leaf Ratio – ULR, comummente designado por NAR) e rácio de área foliar (Leaf Area Ratio – LAR), foram calculados. A expansão da área foliar decresceu com o aumento de salinidade. A produtividadefisiológica máxima (ULR) foi atingida nos 100 Mm NaCl. LAR foi provavelmente o maior responsável pelo ligeiro aumento nos valores de RGR, já que o ULR se manteve relativamente constante. No entanto o crescimento relativo manteve-se constante até 100 mM NaCl não apresentando diferençassignificativas. A acumulação de iões como Ca2+, Mg2+, K+, decresceu com o aumento da salinidade, ocorrendo comportamento inverso com o Na+, que atingiu valores bastante elevados nas salinidades mais altas. O rácio Na/K aumentou significativamente com o aumento da salinidade, sendo de notar que nas folhas velhas se obtiveram valores muito mais baixos que nas folhas novas, o que é indicativo da compartimentação do Na+ para as folhas mais velhas. O conteúdo total de polifenóis e do flavonóide queracitina foi máximo nos 50 mM NaCl. O conteúdo em azoto decresceu com o aumento da salinidade mas não tão acentuadamente como nos restantes iões (Ca2+, Mg2+, K+). Os resultados revelaram um crescimento óptimo desta planta asalinidades moderadas, com o máximo de produtividade (peso seco) a ser atingido a 100 mM NaCl. De acordo com o sistema de classificação usado, Diplotaxis tenuifolia foi classificada como uma espécie tolerante ao sal até um valor de salinidade máximo de 100 mM. Os resultados deste trabalho servirãode ajuda a programas de implementação de culturas de agricultura salina que visam uma maior sustentabilidade agrícola.
Bannwarth, E. "Pancytopénie au méthotrexate à faible dose dans la polyarthrite rhumatoi͏̈de : à propos d'un cas et revue de la littérature". Bordeaux 2, 1992. http://www.theses.fr/1992BOR2M203.
Texto completoMartinetti, Florent. "Estimation des doses dues aux neutrons secondaires reçues par les patients en protonthérapie : cas des traitements ophtalmologiques". Paris 11, 2009. http://www.theses.fr/2009PA112250.
Texto completoThe research work conducted during this thesis was to evaluate the neutrons secondary doses received by the organs of the patient outside the treatment field. The study focused on cases of eye treatments performed at the Institut Curie – Centre de Protonthérapie d’Orsay (ICPO). First, a model of the 75 MeV beam line used for the treatments at Orsay has been developed with the Monte Carlo code MCNPX. In a second time, several experimental validations of the model have been performed. They are: (i) the dose distribution of protons in a water phantom, (ii) the ambient dose equivalent due to secondary neutrons, H*(10) and the neutron spectra in the treatment room and (iii) the dose deposited by secondary neutrons in an anthropomorphic phantom. The agreement between simulations and measurements has been deemed sufficiently correct to consider the beam line model as representative of the beam used in clinics et the ICPO. The numerical estimation of secondary doses received by the organs of the patient was performed using a mathematical phantom type MIRD. The absorbed doses due to secondary neutrons were calculated for several organs. The highest values, estimated for the non treated eye, brain and thyroid, are respectively equal to 800, 310 and 235 μGy for a therapeutic dose of 60 GyE (60Co equivalent) delivered to the eye. The organs receiving an equivalent dose greater than 1 mSv are those located on the anterior part of the body directly exposed to neutrons generated in the beam line. A factor of 10 on the equivalent dose is observed between the organs located near the treated area and those located deeper and far from the treatment field. Using the concept of effective dose is not well adapted to characterize the radiological protection of patients in proton therapy
Rosenthal, Robert. "How does student teacher research contribute to knowledge creation within the secondary school context?" Thesis, University of Sussex, 2014. http://sro.sussex.ac.uk/id/eprint/51479/.
Texto completoRiemen, Anna Helene Katrin. "Does synovial hyperplasia after traumatic joint surface injury affect the development of secondary osteoarthritis?" Thesis, University of Aberdeen, 2018. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=239453.
Texto completoAndersson, Claes. "How does the moving of the family affect the outcome in swedish secondary school?" Thesis, Malmö högskola, Fakulteten för lärande och samhälle (LS), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-27944.
Texto completoHow the moving of the family affect student outcome in Swedish secondary school. I found that students in a community that have moved at least once during their nine years in the Swedish compulsory school get significantly lower grades than others.
Gerrard, Edward. "How does coursework based study affect the learning of pupils in secondary science education?" Thesis, University of Gloucestershire, 2010. http://eprints.glos.ac.uk/3254/.
Texto completoLeech, Andrea Dawn. ""What Does This Graph Mean?" Formative Assessment With Science Inquiry to Improve Data Analysis". PDXScholar, 2014. https://pdxscholar.library.pdx.edu/open_access_etds/1537.
Texto completo陳素心 y So-sum Chan. "How does principal's leadership influence teachers' beliefs?: case study of a secondary school in HongKong". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2002. http://hub.hku.hk/bib/B31962798.
Texto completoDewar, Louise H. "The advanced placement program| Does the cost outweigh the value for independent schools in the 21st century?" Thesis, College of Saint Elizabeth, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3619006.
Texto completoThe purpose of this action research, mixed methods study was to explore the impact of the AP Program on the high school and college experience of students, both from an academic and a "lived experience" perspective. In addition, the study investigated the costs and values of the AP Program to the institution itself. The study revealed that the AP Program continues to contribute significant value to students' high school educations, generally prepares them well for success at college, and often contributes to the acquisition of important credit and placement accommodations for students when matriculating at college. The study also revealed that, although the Program contributes a great deal of stress to the high school experience, students do not see this as a significant impediment to participation. However, the study also revealed several opportunities for the institution to better prepare students for the rigor of the Program and their use of AP scores in obtaining accommodations at college. Finally, the study demonstrated that while the AP Program contributes important value to the teaching experience, marketing of the institution, and the college admissions success of the school, there are important issues that warrant further consideration and review, not the least of which is the quality of the non-AP curriculum that is offered to students who do not meet the prerequisites of the AP Program.
Reeves, Todd. "Does Content Knowledge Matter for New Teachers?" Thesis, Boston College, 2013. http://hdl.handle.net/2345/3346.
Texto completoThere is considerable evidence that new teachers are ill prepared for classroom practice, including self-reported evidence collected from teachers (e.g., Levine, 2006), and statistical evidence for differences in the achievement of students with new versus more experienced teachers (Rivkin, Hanushek, and Kain, 2005). In light of the challenges encountered by new teachers (e.g., Levine, 2006), this study examined the value of different forms of teacher knowledge for teachers with different levels of experience. In particular, this study investigated the interactive relationship between teaching experience and teacher content knowledge, and student achievement in mathematics and science. In New York City, Boyd et al. (2009) linked practice-focused teacher preparation to student mathematics achievement in the first year of teaching and teacher content preparation to achievement in the second. However, other studies demonstrated interactions between teaching experience and content knowledge with different interpretations (e.g., Kukla-Acevedo, 2009; Monk, 1994). At the same time, this study examined the interactive relationship between teaching experience and teachers' pedagogical content knowledge, and student achievement. Extant models of teacher career development (Huberman, 1989; National Research Council, 2010) and how teacher education affects student achievement (e.g., Desimone, 2009) offered theoretical grounding for the study. With nationally representative samples of fourth and eighth grade U.S. students--participants in the 2011 Trends in International Mathematics and Science Study--this study employed hierarchical linear modeling to address its research questions among an array of student achievement outcomes in the domains of mathematics and science. This study attempted to account for salient student, teacher, and contextual factors, and the probabilities of teachers' receipt of various teacher education "treatments" (i.e., propensity score analysis) to reduce the plausibility of selection threats to internal validity. The study found no evidence for relationships between teacher content knowledge or pedagogical content knowledge and student mathematics and science achievement in fourth and eighth grade. Furthermore, the results indicated no interactive relationships between forms of teacher knowledge and teaching experience, and student achievement in these grades/subjects. The limitations of cross-sectional, observational studies using large-scale data and directions for further research are discussed
Thesis (PhD) — Boston College, 2013
Submitted to: Boston College. Lynch School of Education
Discipline: Educational Research, Measurement, and Evaluation
Gonon, Géraldine. "Space radiation-induced bystander effect : kinetics of biologic responses, mechanisms, and significance of secondary radiations". Phd thesis, Université de Franche-Comté, 2011. http://tel.archives-ouvertes.fr/tel-00987717.
Texto completoWatts, Kim. "Does teenage pregnancy and childbirth really increase risk? : exploring outcomes through secondary analysis of NHS data". Thesis, University of Nottingham, 2010. http://eprints.nottingham.ac.uk/12590/.
Texto completoTong, Chung-fan y 湯仲勳. "How does the teamwork culture affect the teachers' ways of working in a local secondary school?" Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B30257141.
Texto completoDavids, Eugene Lee. "Does family structure matter? A comparison of the goals and aspirations of learners in secondary school". University of the Western Cape, 2012. http://hdl.handle.net/11394/5115.
Texto completoSelf Determination Theory (SDT) proposes that individuals are motivated to have goals and aspirations which are either intrinsic or extrinsic in nature. Intrinsic life goals are associated with greater psychological health and well-being. Research shows that family structure plays a role in the way children are raised and has implications for later adult adjustment. In South Africa 42.8% of children are raised in a single parent household. This study aimed to compare the goals and aspirations of learners from single and married parent households. The study used a quantitative methodology with a cross-sectional comparative research design. The sample consisted of 853 Grade 11 learners from schools in the Northern, Southern and Metro Central Education Districts in the Western Cape. The data was collected using a selfreport questionnaire that consisted of two sections, demographical information and the Aspirations Index. The Aspirations Index assessed the life goals of the learners and categorised the goals and aspirations into intrinsic and extrinsic life goals. The data was analysed using the Statistical Package for Social Sciences V20 (SPSS). The results suggest that there was a significant main effect of family structure on certain goals and aspirations of Grade 11 learners in secondary schools. These goals and aspirations included wealth, image, personal growth, relationships and health. Furthermore, participants from single parent households placed more emphasis on intrinsic goals than participants from married parent.
Chan, So-sum. "How does principal's leadership influence teachers' beliefs? : case study of a secondary school in Hong Kong /". Hong Kong : University of Hong Kong, 2002. http://sunzi.lib.hku.hk/hkuto/record.jsp?B25752091.
Texto completoWood, J. M. "To what extent does school leadership facilitate Community Cohesion for students in an English secondary school?" Thesis, University College London (University of London), 2017. http://discovery.ucl.ac.uk/1536125/.
Texto completoSvensson, Ofir. "Does small-scale land use affect the understory birds negative in the Peruvian National Reserve Allpahuayo Mishana?" Thesis, Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-25017.
Texto completoVardinakis, Mindie H. C. "Does Student Choice Improve Students' Attitudes Toward their Language Arts Class?" Defiance College / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=def1281705744.
Texto completoHostutler, Roger Allen. "Comparison of Effects of Daily and Pulse Dose Calcitriol in Treating Renal Secondary Hyperparathyroidism in Cats with Primary Chronic Renal Failure". The Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=osu1396282849.
Texto completoCardoso, Jorge Luiz. "Evaluation of the precipitation of secondary phases on CO2 environment corrosion resistance of austenitic and super austenitic stainless steels". reponame:Repositório Institucional da UFC, 2016. http://www.repositorio.ufc.br/handle/riufc/18440.
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Austenitic stainless steels are widely used in several applications including the manufacture of pipelines for the oil and gas industry. This work discusses the corrosion behavior of austenitic and super austenitic stainless steels in CO2-containing environments. The steels used in this work were the AL-6XN PLUS™ (UNS Designation N08367) and 904L (UNS Designation N08904) super austenitic stainless steels. Two conventional austenitic stainless steels, 316L (UNS S31600/ S31603) and 317L (UNS S31703) were also used for comparison purposes. Potentiodynamic polarization measurements were taken in CO2-saturated synthetic oil field formation water, deaerated with nitrogen to simulate some conditions in the pre-salt region. Potentiostatic measurements were also carried out to evaluate the corrosive level of the solution without the presence of CO2. Pressurized experiments using autoclave in CO2-containing environment and in synthetic air environment were also conducted to evaluate the corrosion resistance of the alloys when pressure and temperature act together. Heat treatments at high temperatures between 600 °C and 760°C in different ranges of time were also conducted to evaluate the possible sigma phase precipitation and its effect on the corrosion resistance. The AL-6XN PLUS™ and 904L super austenitic stainless steels showed a good performance in CO2-containing environment. The AL-6XN PLUS™ steel also exhibited the best performance in the pressurized experiments. The conventional 316L and 317L steels showed susceptibility to pitting and crevice corrosion. The results showed that the conventional alloys are not suitable for the use in CO2-containing environment under severe conditions. Pitting potential of the 316L alloy was affected by the pH of the solution in CO2-saturated solution. No sigma phase precipitated in the heat treatments for the range of time used indicating that its precipitation kinetics in austenitic stainless steels is very slow. This result is an advantage when working with austenitic stainless steels for long periods of exposure at high temperatures.
Os aços inoxidáveis austeníticos e super austenític os são amplamente utilizados na fabricação de tubulações na industria de petróleo e gás. Esse trabalho discute o comportamento da corrosão de aços inoxidáveis austeníticos e super a usteníticos em meio contendo CO 2 . Os aços usados nesse trabalho foram os aços super aust eníticos AL-6XN PLUS™ (Designação UNS N08367) e 904L (Designação UNS N08904). Dois aç os austeníticos convencionais, 316L (UNS S31600/ S31603) e 317L (UNS S31703), tamb ém foram usados para comparação. Foram realizadas medidas de polarização potenciodinâmica em água artificial de formação de poço de petróleo saturada com CO 2 e desaerada com nitrogênio para simular algumas condições do pré-sal. Foram também realizad as medidas potenciostáticas para avaliar o nível corrosivo da solução sem a presença de CO 2 . Experimentos pressurizados usando autoclaves em meio contendo CO 2 e ar sintético também foram realizados para avalia r a resistência à corrosão das ligas quando pressão e t emperatura agem juntas. Foram realizados tratamentos térmicos em altas temperaturas entre 60 0 °C e 760 °C em diferentes faixas de tempo para avaliar a formação de fase sigma e seu e feito na resistência à corrosão. Os aços super austeníticos AL-6XN PLUS™ e 904L mostraram um a boa performance em meio contendo CO 2 . O aço AL-6XN PLUS™ também exibiu uma boa performa nce nos experimentos pressurizados. Os aços convencionais 3 16L e 317L apresentaram susceptibilidade à corrosão por pites e frestas. Os resultados mostraram que os aços convencionais não são apropriados para uso em meio contendo CO 2 sob condições severas. O potencial de pite do aço 316L foi afetado pelo pH d a solução em meio saturado com CO 2 . Não houve precipitação de fase sigma nos tratamento s térmicos para as faixas de tempo usadas indicando que sua cinética de precipitação e m aços inoxidáveis austeníticos é muito lenta. Esse resultado é uma vantagem ao se trabalha r com aço inoxidáveis austeníticos em logos períodos de exposição em altas temperaturas.
Minjares, Amador Jr. "Human skeletal remains of the ancient Maya in the caves of Dos Pilas, Guatemala". Thesis, Texas A&M University, 2003. http://hdl.handle.net/1969.1/243.
Texto completoPetersson, Theres. "Peer Feedback in a Swedish EFL Textbook -Does it align with best practices?" Thesis, Örebro universitet, Institutionen för humaniora, utbildnings- och samhällsvetenskap, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-92956.
Texto completoChiu, Suk-kwan y 趙淑君. "Does the relative age effect (RAE) exist in the selection of athletes in Hong Kong secondary schools?" Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B45013834.
Texto completoBhogal, Balbir Kaur. "How does patient choice impact on secondary care : an in depth investigation in a large teaching hospital". Thesis, University of Birmingham, 2016. http://etheses.bham.ac.uk//id/eprint/6490/.
Texto completoBrooks, Kanini Wanjira Ward. "Does an Online Post-baccalaureate Secondary Teacher Certification Program Produce Certified Teachers Who Remain in the Field?" Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc804832/.
Texto completoFaaulufalega, Tailetai Pale. "How does Culture Impact on Educational Leadership in Samoa?" The University of Waikato, 2008. http://hdl.handle.net/10289/2260.
Texto completoNascimento, HÃlio Oliveira do. "Study of the chemical and cytotoxic potential of secondary metabolites of endophytic fungus Periconia hispidula". Universidade Federal do CearÃ, 2016. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=16271.
Texto completoConselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico
Periconia hispidula is an endophytic fungus isolated from dried leaves from semi-arid dunes of Bahia. The fungus was subjected to cultivation by varying nutritional factors in four different culture mediuns: MPD (malt, peptone and dextrose), BD (potato dextrose), BDL (potato, dextrose and yeast) and MntPL (mannitol, peptone and yeast), and analyzing the extracts on different incubation days (7, 14, 21, 28 days). A survey of primary cytotoxic activity was carried out from the extracts against tumor cell line of colon cancer (HCT-116). The MPD extracts - 28 days BDL - 28 days and BD - 21 days showed a promising cytotoxic activity and were preliminarily selected for the chemical study. The chromatographic fractionation of MPD-28 days extract resulted in the isolation of 11 secondary metabolites characterized as {4-chromanone, 6-hydroxy-(R) -methyl- (PS-1)}, {4-chromanone, 6-hydroxy-(S) -methyl- (PS-2)}, {E, 1-(2,5 dihydroxyphenyl) but-2-en-1-one (PS-3)}, {1-(2, 5 dihydroxyphenyl)-butan-1-one (PS-4)}, {Z-methyl-3-(3-hydroxyphenyl) propenoate (PS-5)}, modiolide A (PS-7), fusanolide B (PS-8), stagonolide E (PS-9), {(3R,4R)-3,4-dihydro, 3,4,8- trihdroxy, naphthalen-1(2H)-one (PS-11)}, {(4S) isosclerona (PS-12)}, furtermore PS-10 without structural characterization yet. The BDL-BD-28 days and 21 days extracts presented a chromatographic profile very similar to MPD-28 days extract, thus, the chromatographic fractionations of both extracts were targeted for isolation of substances absent in MPD-28 days. The 3,4 dihydoxy-benzoic acid was isolated just from the BD-extract 21 days, while the fractionation of the extract BDL 28days gave (PS-13 without structural characterization yet) as different. Among the isolated metabolites, {4-chromanone, 6-hydroxy-(S) -methyl- (PS-2)}, fusanolido B and PS10 (probably) showed were new compounds. The isolated compounds were shown to be inactive in cytotoxicity assays against strains of HCT-116 and MC-27 (breast adenocarcinoma). However, the 1- (2,5-dihydroxyphenyl) but-2-en-1-one showed strong inhibition with a MIC of 62.5 Âg/mL to be subjected to antimicrobial test against strains of fungi Candida Krusei (ATCCÂ 142432TM) and Candida albicans (ATCCÂ 10231TM) and CIM of 125 Âg/mL against Candida parapsilosis (ATCCÂ 22019TM), while {4-chromanone, 6-hydroxy-(S) -methyl-}, Z-3-(3-hydroxyphenyl) propenoate methyl, modiolide A, estagonolide E, fusanolido B and 3R,4R-dihydro-3,4,8-trihydroxy-1-(2H) -naftalelone showed moderate activity with MIC of 500 Âg / mL.Usual chromatographic techniques including liquid-liquid partitioning, flash chromatography and high pressure liquid chromatography (HPLC) were used for the isolation of secondary metabolites, while the structural characterization was possible through the use of spectrometric techniques using infrared (IR), mass spectrometry (MS), and uni and bidimensional techniques of nuclear magnetic resonance (NMR), and comparison with literature data.
Periconia hipidula à um fungo endofÃtico isolado de folhas secas provenientes de dunas do semiÃrido do estado da Bahia. O fungo foi submetido ao cultivo atravÃs da variaÃÃo de fatores nutricionais em quatro meios diferentes: MPD (malte, peptona e dextrose), BD (batata, dextrose), BDL (batata, dextrose e levedura) e MntPL (manitol, peptona e levedura), e anÃlise dos extratos em diferentes dias de incubaÃÃo (7, 14, 21, 28 dias). A prospecÃÃo da atividade citotÃxica preliminar foi realizada a partir dos extratos obtidos frente à linhagem de cÃlulas tumorais de cÃncer de cÃlon (HCT-116). Os extratos MPD â 28 dias, BDL - 28 dias e BD - 21 dias apresentaram uma atividade citotÃxica promissora e foram preliminarmente selecionados para o estudo quÃmico. O fracionamento cromatogrÃfico do extrato MPD-28 dias, resultou no isolamento de 11 metabÃlitos secundÃrios caracterizados como {(R), 6-hidroxi-2-metil, 4-cromanona (PS-1)}, { (S), 6-hidroxi-2-metil, 4-cromanona (PS-2)}, {E, 1-(2,5 diidroxi-fenil) but-2-en-1-ona (PS-3)}, {1-(2, 5 diidroxi-fenil)-butan-1-ona (PS-4)}, Z-3-(3 hidroxifenil) propenoato de metila (PS-5), modiolido A (PS-7), fusanolido B (PS-8), estagonolido E (PS-9), {(3R,4R)-3,4diidro,3,4,8 triidroxi,naftalen-1-(2H)-ona (PS-11)}, (4S)-isosclerona (PS-12), alÃm de PS-10 que se encontram em fase de caracterizaÃÃo estrutural. Os extratos BDL-28 dias e BD-21 dias apresentaram um perfil cromatogrÃfico bastante semelhante ao extrato MPD-28 dias, desta forma, os fracionamentos cromatogrÃficos de ambos os extratos foram direcionados para o isolamento de substÃncias ausentes em MPD-28 dias. O Ãcido 3,4 diidroxi-benzÃico (PS-6) foi isolado apenas do extrato BD-21 dias, enquanto que o fracionamento do extrato BDL 28d forneceu PS-13 (em fase de caracterizaÃÃo estrutural) como diferente. Dentre os metabÃlitos isolados, os compostos (2S)-6-hidroxi-2-metil-4-cromanona, fusanolido B apresentaram carÃter inÃdito na literatura. Os compostos isolados mostraram-se inativos em ensaios de atividade citotÃxica frente a cepas de HCT-116 e MC-27 (adenocarcinoma de mama). No entanto, o composto 1-(2,5-diidroxifenil)-but-2-en-1-ona apresentou elevada inibiÃÃo com CIM de 62,5 Âg/mL ao ser submetido à ensaio antimicrobiano frente a cepas de fungos Candida Krusei (ATCC 142432TM) e Candida albicans (ATCC 10231TM) e 125 Âg/mL frente à Candida parapsilosis (ATCC 22019TM), enquanto que o (2R)-6-hidroxi-2-metil-4-cromanona, Z-3-(3-hidroxifenil)-propenoato de metila, o modiolido A, o estagonolido E, o fusanolido B e a 3,4-diidro- 3,4,8-triidroxi-1(2H)-naftalelona apresentaram moderada atividade com CIM de 500 Âg/mL. TÃcnicas cromatogrÃficas usuais, incluindo partiÃÃo lÃquido-lÃquido, coluna de sÃlica flash e cromatografia de alta eficiÃncia (CLAE) foram utilizadas para o isolamento dos metabÃlitos secundÃrios, enquanto que a caracterizaÃÃo estrutural foi possÃvel atravÃs do uso de tÃcnicas espectromÃtricas utilizando infravermelho (IV), espectrometria de massa (EM) e ressonÃncia magnÃtica nuclear (RMN) com experimentos uni e bidimensionais, alÃm de comparaÃÃo com dados da literatura.
Smith, D. L. "What does religious education achieve? : an investigation into the effect of secondary school pupils' experience of religious education on their attitude to religion". Thesis, University of Wales Trinity Saint David, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.683379.
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