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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.
11

New methods for high resolution 3D imaging with X-rays

Pratsch, Christoph 21 June 2018 (has links)
In der Arbeit haben wir die Grenzen der weit verbreiteten tomographischen Rekonstruktion von 3D-Proben mittels Transmissionsröntgenmikroskopie charakterisiert. Wir zeigen, dass die 3D-Auflösung mit diesem Ansatz durch die Schärfentiefe begrenzt ist. Zur Untersuchung von Alternativen führten wir Simulationen zur Bildentstehung in einem konfokalen Röntgenmikroskop und einem FIB-SXM durch. Wir zeigen, dass FIB-SXM ein vielversprechender Ansatz ist, der eine isotrope 3D-Aulösung um die 10 nm erreichen kann und zusätzlich ein drastisch verbessertes Signal-Rausch-Verhältnis bieten könnte. Wir stellen auch eine neue Holographiemethode vor, die sich für Vollfeldabbildungen mit kurzen kohärenten Röntgenpulsen als vorteilhaft erweisen und neue Einsichten in die ultraschnelle Physik liefern könnte. / We have characterized the limitations of the most powerful and widely used 3D X-ray imaging approach, transmission X-ray microscopy with tomographic reconstruction. We show that 3D resolution in this approach is limited by the depth of field. To investigate alternatives, we perform simulations of a confocal transmission X-ray microscope and a FIB-SXM. We show that FIB-SXM is a very promising approach that could o er 3D isotropic resolution at 10 nm with dramatically improved signal to noise. We also introduce a new holography method that could prove bene cial for full eld imaging with short coherent X-ray pulses and yield new insights into ultrafast physics.
12

Materials Approaches for Transparent Electronics

Iheomamere, Chukwudi E. 12 1900 (has links)
This dissertation tested the hypothesis that energy transferred from a plasma or plume can be used to optimize the structure, chemistry, topography, optical and electrical properties of pulsed laser deposited and sputtered thin-films of ZnO, a-BOxNy, and few layer 2H-WS2 for transparent electronics devices fabricated without substrate heating or with low substrate heating. Thus, the approach would be compatible with low-temperature, flexible/bendable substrates. Proof of this concept was demonstrated by first optimizing the processing-structure-properties correlations then showing switching from accumulation to inversion in ITO/a-BOxNy/ZnO and ITO/a-BOxNy/2H-WS2 transparent MIS capacitors fabricated using the stated processes. The growth processes involved the optimization of the individual materials followed by growing the multilayer stacks to form MIS structures. ZnO was selected because of its wide bandgap that is transparent over the visible range, WS2 was selected because in few-layer form it is transparent, and a-BOxNy was used as the gate insulator because of its reported atomic smoothness and low dangling bond concentration. The measured semiconductor-insulator interfacial trap properties fall in the range reported in the literature for SiO2/Si MOS structures. X-ray photoelectron spectroscopy (XPS), Hall, photoluminescence, UV-Vis absorption, and X-ray diffraction (XRD) measurements investigated the low-temperature synthesis of ZnO. All films are nanocrystalline with the (002) XRD planes becoming more prominent in films grown with lower RF power or higher pressure. Low power or high chamber pressure during RF magnetron sputtering resulted in a slower growth rate and lower energetic conditions at the substrate. Stoichiometry improved with RF power. The measurements show a decrease in carrier concentration from 6.9×1019 cm-3 to 1.4×1019 cm-3 as power increased from 40 W to 120 W, and an increase in carrier concentration from 2.6×1019 cm-3 to 8.6×1019 cm-3 as the deposition pressure increased from 3 to 9 mTorr. The data indicates that in the range of conditions used, bonding, stoichiometry, and film formation are governed by energy transfer from the plasma to the growing film. XPS characterizations, electrical measurements, and atomic force microscopy (AFM) measurements reveal an increase in oxygen concentration, improved dielectric breakdown, and improved surface topography in a-BOxNy films as deposition pressure increased. The maximum breakdown strength obtained was ~8 MVcm-1, which is comparable to a-BN. Metal-Insulator-Metal (MIM) structures of a-BOxNy grown at 10 and 15 mTorr suggest a combination of field-enhanced Schottky emission and Frenkel-Poole emission are likely transport mechanisms in a-BOxNy. In comparison, better fitted data was gotten for field enhanced Schottky emission which suggests the more dominant mechanism. The static dielectric constant range is 3.26 – 3.58 for 10 and 15 mTorr films. Spectroscopic ellipsometry and UV-Vis spectroscopy measured a bandgap of 3.9 eV for 15 mTorr grown a-BOxNy. 2H-WS2 films were grown on both quartz and a-BOxNy which revealed that the XRD (002) planes became more prominent as substrate temperature increased to 400 oC. AFM shows nano-grains at lower growth pressure. Increasing the growth pressure to 1 Torr resulted in the formation of larger particles. XPS chemical analysis reveals improved sulfur to tungsten ratios as pressure increased. Sulfur deficient films were n-type, whereas sulfur rich conditions produced p-type films. Frequency dependent C-V and G-V measurements revealed an interface trap concentration (Nit) of 7.3×1010 cm-2 and interface state density (Nss) of 7.5×1012 eV-1cm-2 for the transparent ITO/a-BOxNy/ZnO MIS structures, and approximately 2 V was required to switch the a-BOxNy/ZnO interface from accumulation to inversion. Using 2H-WS2 as the channel material, the ITO/a-BOxNy/2H-WS2 required approximately 4 V to switch from inversion to accumulation in both n and p-channel MIS structures. Interface trap concentrations (Nit) of 1.6×1012 cm-2 and 3.2×1010 cm-2, and interface state densities (Nss) of 1.6×1012 eV-1cm-2 and 6.5×1012 eV-1cm-2 were calculated for n and p-channel 2H-WS2 MIS structures, respectively. The data from these studies validate the hypothesis and demonstrate the potential of ZnO, a-BOxNy, and few layer 2H-WS2 for transparent electronics.
13

Électrochimie et spectroscopie Raman de matériaux d’électrode positive pour batteries Li-ion / Electrochemistry and Raman study of positive electrode as materials for Li-ion batteries

Dridi Zrelli, Yosra 08 November 2012 (has links)
Dans ce travail de thèse, la microspectrométrie Raman a été mise à profit pour décrire les changements structuraux induits par la réaction électrochimique d'insertion/désinsertion des ions lithium dans des composés de structure lamellaire LiCoO2 et cubique LiMn2O4 et LiNi0.4Mn1.6O4, utilisés comme électrodes positives dans les batteries Li-ion. L'étude du composé d'électrode LiCoO2 pendant le processus de charge permet de mettre en évidence une région biphasée où la phase initiale coexiste avec une nouvelle phase hexagonale caractérisée par une expansion du paramètre inter-feuillets de l'ordre de 3% et un affaiblissement de la liaison Co-O dans le plan des feuillets. Dans le cas de LiMn2O4, une nouvelle attribution du spectre Raman a pu être proposée. Pendant la charge à 4V, un mécanisme à trois phases (phase initiale LiMn2O4, phase intermédiaire, phase pauvre en lithium) est décrit par spectroscopie Raman alors que la diffraction des RX ne permet pas d'observer la phase intermédiaire dans nos conditions de mesure. L'étude de l'insertion électrochimique du lithium dans LiMn2O4 (région 3V), a permis de montrer pour la première fois par spectroscopie Raman la formation progressive d'une phase tétragonale de composition Li2Mn2O4 qui coexiste avec la phase cubique initiale et qui est pure en fin de décharge. La réversibilité de cette transition structurale a également été démontrée. Dans le cas du composé substitué au nickel, LiNi0.4Mn1.6O4, une attribution complète du spectre Raman est proposée pour la première fois. L'étude par diffraction des RX du matériau en fonction de l'état de charge et de décharge met en évidence une conservation de la structure cubique avec des variations modérées de paramètres de maille. Le spectre Raman présente quant à lui des variations très significatives qui rendent compte de la présence dans des proportions différentes des espèces redox impliquées dans le fonctionnement électrochimique (Mn4+, Mn3+, Ni2+, Ni3+, Ni4+). Une analyse spectrale par décompositions de bandes permet d'identifier et de quantifier les proportions relatives des différents couples redox du nickel. Une réversibilité complète de la signature Raman est observée en décharge. Une application concrète et originale de la spectroscopie Raman a consisté à étudier le mécanisme d'autodécharge qui est observé pour le matériau LiNi0.4Mn1.6O4 complètement chargé. L'évolution des spectres Raman permet de mettre en évidence une réduction rapide et quantitative des ions Ni4+ pendant les premières heures de séjour dans l'électrolyte, puis un processus plus lent de réduction des ions Ni3+. Enfin, pour la première fois également, l'insertion du lithium dans le composé LiNi0.4Mn1.6O4 a été explorée par microspectrométrie Raman et a permis notamment d'identifier l'empreinte Raman de la phase la plus réduite de symétrie tétragonale Li2Ni0.4Mn1.6O4. L'originalité de ce travail a été d'apporter un grand nombre de données Raman expérimentales sur des matériaux d'électrode performants fonctionnant à 4V. De nouvelles attributions ont pu être proposées pour les composés initiaux, et des données vibrationnelles inédites ont été fournies sur les composés formés en charge et en décharge. Dans certains cas, ces données ont permis, sur la base d'une analyse détaillée des spectres Raman par décompositions de bandes, de proposer un raisonnement quantitatif sur l'existence de phases ou d'espèces redox en mélange. Il conviendrait bien sûr de corroborer ces nouvelles données et attributions par des calculs théoriques ab initio capables de simuler les fréquences et les intensités des modes vibrationnels dans les structures hôtes et lithiées / In this work, we show the relevance of Raman spectroscopy as a useful technique to investigate the local changes induced by the electrochemical reaction of intercalation/deintercalation of lithium in positive electrode materials for rechargeable lithium ion batteries.Raman investigations concern three types of high voltage cathode materials (4-5Volts) which are layered LiCoO2 and cubic LiMn2O4 and LiNi0.4Mn1.6O4.During electrochemical deintercalation of LiCoO2, we show the existence of a two phase region where the initial hexagonal phase coexist with a second hexagonal phase with a 3% expansion of the lattice parameter indicating a weakening of the Co-O bond in the Li1-xCoO2 material.On the other hand, a new assignment of LiMn2O4 Raman spectrum was proposed. During the charge in the 4V region, a three region phase (initial LiMn2O4 phase, intermediary phase and poor lithium phase) was described using Raman spectroscopy. RX measurements can not detect this intermediary phase. Lithiated phase Raman signature shows a specific local order: Fd3m for extreme phases and F43m for partially lithiated phase. A rich Raman band spectrum is attributed to this later phase in coherence with literature calculations. Structural changes reversibility is demonstrated. Identification of this intermediary phase as a major component of a cycled electrode, underline the incomplete reduction and explain the important loss of capacity observed during cycling. Raman study of LiMn2O4 electrochemical insertion in the 3V region, has demonstrated for the first time a progressive formation of tetragonal Li2Mn2O4 phase, which is in coexistence with initial cubic phase and is pure at the end of discharge. Structural transition reversibility was also demonstrated.In the case of LiNi0.4Mn1.6O4, the assignment of the Raman spectrum of LiNi0.4Mn1.6O4 is provided for the first time. DRX study in function of the state of charge and discharge, exhibit cubic structure conservation with moderate lattice parameters variations. The Raman spectrum of the spinel oxide exhibits drastic spectral changes during Li extraction. These changes have been directly related to the Mn and Ni oxidation states in the cathode material under operation. It comes out that electrochemical reactions of LiNi0.4Mn1.6O4 are reversible and based on three redox couples of Mn3+/Mn4+, Ni2+/Ni3+, and Ni3+/Ni4+. An original and concrete Raman spectroscopy application is the study of self discharge mechanism of completely charged LiNi0.4Mn1.6O4. Raman spectra evolution exhibits a quantitative Ni4+ reduction during the first hours, and then a slower Ni3+ reduction process. Finally, LiNi0.4Mn1.6O4 lithium insertion has been explored for the first time using Raman spectroscopy, and a tetragonal Li2Ni0.4Mn1.6O4 phase has been identified.The originality of this work is the important number of experimental Raman data of 4V electrode materials. New assignment of initial compound has been proposed and original vibrationnal data of compound during charge/discharge has been presented. These Raman data has permitted to propose a quantitative explanation which must be completed with ab initio calculations to simulate vibrationnal modes frequencies/ intensities
14

Étude et modélisation mécanique de la cristallisation induite par la déformation des polymères : caoutchouc naturel réticulé et PET / Study and mechanical modeling of the strain-induced-crystallization of polymers : crosslinked naturel rubber and PET

Quandalle, Grégoire 28 March 2017 (has links)
L’objectif de cette thèse est de contribuer à la compréhension et à la modélisation de la cristallisation induite. Le phénomène est caractérisé pour deux matériaux : le PET et le caoutchouc naturel réticulé. Les conditions favorables au phénomène, de type caoutchoutique sont déterminées par analyses calorimétriques et spectroscopiques. La microstructure qui se développe au cours de la déformation est observée par diffraction des rayons X.Le PET est déformé en traction uni- et biaxiale. Une partie des étirages est suivie d’une relaxation des contraintes, une autre est suivie d’une trempe rapide. Il ressort de l’étude que l’étirage du PET dans ces conditions n’aboutit pas à l’obtention d’un cristal PET avec toutes les périodicités qui lui sont propres.Le caoutchouc naturel est déformé en traction uniaxiale et en cisaillement précédé d’un étirage uniaxial. En cisaillement, la phase cristalline obtenue au cours du pré-étirage ou du cisaillement tourne et tend à s’orienter comme les directions des déformations principales mais avec un retard angulaire. L’extension principale est utilisée pour étudier la phase cristalline obtenue pour les différents modes de sollicitation.Un modèle de comportement visco-hyperélastique, décrit dans le cadre de la thermodynamique des processus irréversibles, est étendu afin de reproduire le durcissement mécanique lié au développement d’une phase organisée/cristalline. Le modèle permet de reproduire les différents comportements mécaniques observés expérimentalement. / The present PhD thesis aims at a better understanding and modeling of strain-induced-crystallization. The phenomenon is characterized for two polymers: PET and crosslinked natural rubber. Strain conditions leading to strain-induced-crystallization are determined by thermal and dynamic mechanical analysis. The developing microstructure is observed by X-ray scattering.The PET is stretched in uni- and biaxial tension. A part of samples is rapidly quenched after stretching and another is submitted to a stress relaxation after stretching. The studies demonstrate that the stretching of PET does not enable the formation of a complete PET crystal with all its own families of planes.The crosslinked natural rubber is stretched in uniaxial tension and in shear preceded by uniaxial stretching. In shear, the crystalline phase, appeared during the pre-stretching or during the shear rotates and has a tendency to orient as the directions of the principal strains. The principal elongation is used to compare the crystallization under the different stresses.A constitutive modeling for visco-hyperelastic behaviors, in a complete thermodynamics framework of irreversible processes, is extended in order to reproduce le mechanical hardening related to the development of an organized/crystalline phase. The modeling successes in reproducing the experimental behaviors in uploading/unloading for various strain conditions.
15

Traumatismo cranioencefálico: correlação entre dados demográficos, escala de Glasgow e tomografia computadorizada de crânio com a mortalidade em curto prazo na cidade de Maceió, Alagoas / Traumatic head injury: correlation of demographic data, the Glasgow coma scale, and cranial computer tomography with short-term mortality in the city of Maceió, Alagoas, Brazil

Rocha, Christiana Maia Nobre 05 February 2007 (has links)
O traumatismo cranioencefálico (TCE) constitui um dos principais problemas de saúde pública mundial e as suas características variam de acordo com a população envolvida, sendo de suma importância o conhecimento de dados demográficos da mesma para que sejam adotadas medidas de prevenção efetivas. Tivemos como objetivos a descrição de dados demográficos e tomográficos em pacientes vítimas de TCE e a correlação entre idade, sexo, escala de Glasgow e dados tomográficos com a mortalidade em curto prazo. Neste estudo transversal e prospectivo realizado em pacientes vítimas de TCE admitidos na Unidade de Emergência Dr. Armando Lages, Maceió, Alagoas, foram incluídos 623 pacientes para descrição dos dados demográficos e 451 pacientes, para a análise de correlação; realizada por meio da Análise de Correlação de Spearman e de análise multivariada através de regressão logística. Foi constatada uma razão masculino/feminino geral de 3,54: 1 e a faixa etária mais acometida foi a de 21 a 30 anos. Os principais mecanismos do trauma foram os acidentes relacionados com meio de transporte motorizado (35,15%), as quedas (32,59%) e as agressões com ou sem armas (22,79%). As alterações mais comuns no TCE leve foram o hematoma subgaleal e/ou palpebral (48,5%), as fraturas (28,3%) e as contusões cerebrais (12,2%). No TCE moderado, as alterações mais freqüentes foram o hematoma subgaleal/palpebral (68,9%), fraturas (43,2%), contusão cerebral (33,7%) e hemorragia subaracnóide (HSA) (28,4%). No TCE grave, as anormalidades mais comuns foram a a HSA (71,1%), o hematoma subgaleal e/ou palpebral (68,9%), as fraturas (64,4%), contusões cerebrais (53,3%) e edema difuso (53,3%). As variáveis relacionadas com a mortalidade, por meio da análise univariada, foram a pontuação 3 na escala de Glasgow, presença de anormalidades tomográficas, de hematoma subdural (HSD), de HSA, apagamento/assimetria de cisternas basais, desvio da linha média, edema difuso, hemorragia intraventricular (HIV), presença de projétil ou estilhaços de arma de fogo. As variáveis sexo, faixa etária e hematoma extradural não apresentaram correlação estatisticamente significante com mortalidade neste estudo. As variáveis preditoras de mortalidade, na análise multivariada, foram valores baixos na escala de Glasgow, presença de anormalidades tomográficas, desvio da linha média e edema difuso. Em conclusão, os pacientes vítimas de TCE apresentaram uma predominância do masculino, numa razão M/F média de 3,54: 1,da faixa etária entre 21 a 30 anos e as causas mais freqüentes de TCE foram a queda de altura, o atropelamento e a agressão física. As características tomográficas mais freqüentes nos grupos de TCE leve e moderado foram: o hematoma subgaleal e/ou palpebral, fratura óssea e contusão cerebral. No TCE grave as lesões mais freqüentes foram a HSA, o hematoma subgaleal e/ou palpebral, fratura óssea, contusão cerebral e edema difuso. Os fatores relacionados com maior mortalidade na análise univariada foram: baixa pontuação na escala de Glasgow, pontuação 3 na escala de Glasgow, presença de anormalidades tomográficas, presença de HSA, presença de HSD, apagamento/assimetria de cisternas basais, desvio linha média, edema difuso, HIV e presença de projétil ou estilhaços de arma de fogo. Na análise multivariada: baixa pontuação na escala de Glasgow, presença de anormalidades tomográficas, presença de desvio da linha média, presença de edema difuso. / The traumatic brain injury (THI) is a major public health concern worldwide. Preventive measures to tackle the problem can be taken after analyzing demographic data and the types of injury affecting the population at hand. Our aim was to outline the demographic and tomographic data from THI victims and determine how tomography findings, age, gender, and Glasgow Coma Scale (GCS) are associated to short-term mortality. The THI patients in this cross-sectional and prospective study had been admitted to the Armando Lages Emergency Care Unit in Maceió, Alagoas. The study comprised 623 patients, who had been clinically diagnosed with THI. A total of 451 patients were included in the investigation into the correlation of computer tomography, age, gender, GCS, and mortality. Both the Spearman Correlation Analysis, and logistic regression multivariate analysis were used. The overall male:female ratio was 3.54, with 78.01% of the victims male and 21.99% female. Most patients fell within the 21 to 30 age bracket. Traffic accidents (35.15%) were the leading cause of head injury, followed by falls (32.59%), and physical assault (22.79%). Tomographic abnormalities were seen in 63.7% of victims of mild THI, the most common being subgaleal and eyelid hematoma (48.5%), skull fractures (28.3%), and cerebral contusion (12.2%). Moderate THI produced tomographic abnormalities in 83.4% of victims, the most frequent being subgaleal and eyelid hematoma (68.9%), fractures (43.2%), cerebral contusion (33.7%), and subarachnoid hemorrhage (SAH) (28.4%). Computer tomography of the skull showed alterations for all victims of severe THI, the most often being subgaleal and eyelid hematoma (68.9%), followed by SAH (71.1%), skull fractures (64.4%), cerebral contusion (53.3%), diffuse brain swelling (53.3%). Univariate analysis attested that a score 3 on the GCS, the presence of tomographic abnormalities, subdural hematoma (SDH), SAH, absent or compressed basal cisterns, midline shift, diffuse brain swelling, intraventricular hemorrhage (IVH), and the presence of a projectile or shell splinters had an statistically significant correlation with short-term mortality. In this study, gender, age group, and large extradural hematoma had no statistical significance as predictive factors for mortality. In a multivariate analysis, the variables that accounted for mortality were low GCS scores, the presence of tomographic abnormalities, midline shift, and diffuse brain swelling. It can be concluded that males were the predominant victims in THI cases, with the M:F ratio at 3.54. Most affected were individuals aged 21 to 30, and the most common causes of THI were falls, being run over by a vehicle, and physical assault. The most frequent tomographic characteristics in the mild and moderate THI cases were subgaleal and/or eyelid hematoma, skull fracture and cerebral contusion. The most common injuries in severe THI patients were subgaleal and/or eyelid hematoma, SAH, skull fracture, cerebral contusion, and diffuse brain swelling. The factors most closely linked to higher mortality after univariate analysis were low GCS scoring, a score 3 on the GCS, the presence of tomographic abnormalities, the presence of SAH, the presence of SDH, absent or compressed basal cisterns, midline shift, diffuse brain swelling, IVH, and the presence of a projectile or shell splinters. After multivariate analysis: low scoring on the GCS and the presence of tomographic abnormalities, midline shift, and diffuse brain swelling.
16

Traumatismo cranioencefálico: correlação entre dados demográficos, escala de Glasgow e tomografia computadorizada de crânio com a mortalidade em curto prazo na cidade de Maceió, Alagoas / Traumatic head injury: correlation of demographic data, the Glasgow coma scale, and cranial computer tomography with short-term mortality in the city of Maceió, Alagoas, Brazil

Christiana Maia Nobre Rocha 05 February 2007 (has links)
O traumatismo cranioencefálico (TCE) constitui um dos principais problemas de saúde pública mundial e as suas características variam de acordo com a população envolvida, sendo de suma importância o conhecimento de dados demográficos da mesma para que sejam adotadas medidas de prevenção efetivas. Tivemos como objetivos a descrição de dados demográficos e tomográficos em pacientes vítimas de TCE e a correlação entre idade, sexo, escala de Glasgow e dados tomográficos com a mortalidade em curto prazo. Neste estudo transversal e prospectivo realizado em pacientes vítimas de TCE admitidos na Unidade de Emergência Dr. Armando Lages, Maceió, Alagoas, foram incluídos 623 pacientes para descrição dos dados demográficos e 451 pacientes, para a análise de correlação; realizada por meio da Análise de Correlação de Spearman e de análise multivariada através de regressão logística. Foi constatada uma razão masculino/feminino geral de 3,54: 1 e a faixa etária mais acometida foi a de 21 a 30 anos. Os principais mecanismos do trauma foram os acidentes relacionados com meio de transporte motorizado (35,15%), as quedas (32,59%) e as agressões com ou sem armas (22,79%). As alterações mais comuns no TCE leve foram o hematoma subgaleal e/ou palpebral (48,5%), as fraturas (28,3%) e as contusões cerebrais (12,2%). No TCE moderado, as alterações mais freqüentes foram o hematoma subgaleal/palpebral (68,9%), fraturas (43,2%), contusão cerebral (33,7%) e hemorragia subaracnóide (HSA) (28,4%). No TCE grave, as anormalidades mais comuns foram a a HSA (71,1%), o hematoma subgaleal e/ou palpebral (68,9%), as fraturas (64,4%), contusões cerebrais (53,3%) e edema difuso (53,3%). As variáveis relacionadas com a mortalidade, por meio da análise univariada, foram a pontuação 3 na escala de Glasgow, presença de anormalidades tomográficas, de hematoma subdural (HSD), de HSA, apagamento/assimetria de cisternas basais, desvio da linha média, edema difuso, hemorragia intraventricular (HIV), presença de projétil ou estilhaços de arma de fogo. As variáveis sexo, faixa etária e hematoma extradural não apresentaram correlação estatisticamente significante com mortalidade neste estudo. As variáveis preditoras de mortalidade, na análise multivariada, foram valores baixos na escala de Glasgow, presença de anormalidades tomográficas, desvio da linha média e edema difuso. Em conclusão, os pacientes vítimas de TCE apresentaram uma predominância do masculino, numa razão M/F média de 3,54: 1,da faixa etária entre 21 a 30 anos e as causas mais freqüentes de TCE foram a queda de altura, o atropelamento e a agressão física. As características tomográficas mais freqüentes nos grupos de TCE leve e moderado foram: o hematoma subgaleal e/ou palpebral, fratura óssea e contusão cerebral. No TCE grave as lesões mais freqüentes foram a HSA, o hematoma subgaleal e/ou palpebral, fratura óssea, contusão cerebral e edema difuso. Os fatores relacionados com maior mortalidade na análise univariada foram: baixa pontuação na escala de Glasgow, pontuação 3 na escala de Glasgow, presença de anormalidades tomográficas, presença de HSA, presença de HSD, apagamento/assimetria de cisternas basais, desvio linha média, edema difuso, HIV e presença de projétil ou estilhaços de arma de fogo. Na análise multivariada: baixa pontuação na escala de Glasgow, presença de anormalidades tomográficas, presença de desvio da linha média, presença de edema difuso. / The traumatic brain injury (THI) is a major public health concern worldwide. Preventive measures to tackle the problem can be taken after analyzing demographic data and the types of injury affecting the population at hand. Our aim was to outline the demographic and tomographic data from THI victims and determine how tomography findings, age, gender, and Glasgow Coma Scale (GCS) are associated to short-term mortality. The THI patients in this cross-sectional and prospective study had been admitted to the Armando Lages Emergency Care Unit in Maceió, Alagoas. The study comprised 623 patients, who had been clinically diagnosed with THI. A total of 451 patients were included in the investigation into the correlation of computer tomography, age, gender, GCS, and mortality. Both the Spearman Correlation Analysis, and logistic regression multivariate analysis were used. The overall male:female ratio was 3.54, with 78.01% of the victims male and 21.99% female. Most patients fell within the 21 to 30 age bracket. Traffic accidents (35.15%) were the leading cause of head injury, followed by falls (32.59%), and physical assault (22.79%). Tomographic abnormalities were seen in 63.7% of victims of mild THI, the most common being subgaleal and eyelid hematoma (48.5%), skull fractures (28.3%), and cerebral contusion (12.2%). Moderate THI produced tomographic abnormalities in 83.4% of victims, the most frequent being subgaleal and eyelid hematoma (68.9%), fractures (43.2%), cerebral contusion (33.7%), and subarachnoid hemorrhage (SAH) (28.4%). Computer tomography of the skull showed alterations for all victims of severe THI, the most often being subgaleal and eyelid hematoma (68.9%), followed by SAH (71.1%), skull fractures (64.4%), cerebral contusion (53.3%), diffuse brain swelling (53.3%). Univariate analysis attested that a score 3 on the GCS, the presence of tomographic abnormalities, subdural hematoma (SDH), SAH, absent or compressed basal cisterns, midline shift, diffuse brain swelling, intraventricular hemorrhage (IVH), and the presence of a projectile or shell splinters had an statistically significant correlation with short-term mortality. In this study, gender, age group, and large extradural hematoma had no statistical significance as predictive factors for mortality. In a multivariate analysis, the variables that accounted for mortality were low GCS scores, the presence of tomographic abnormalities, midline shift, and diffuse brain swelling. It can be concluded that males were the predominant victims in THI cases, with the M:F ratio at 3.54. Most affected were individuals aged 21 to 30, and the most common causes of THI were falls, being run over by a vehicle, and physical assault. The most frequent tomographic characteristics in the mild and moderate THI cases were subgaleal and/or eyelid hematoma, skull fracture and cerebral contusion. The most common injuries in severe THI patients were subgaleal and/or eyelid hematoma, SAH, skull fracture, cerebral contusion, and diffuse brain swelling. The factors most closely linked to higher mortality after univariate analysis were low GCS scoring, a score 3 on the GCS, the presence of tomographic abnormalities, the presence of SAH, the presence of SDH, absent or compressed basal cisterns, midline shift, diffuse brain swelling, IVH, and the presence of a projectile or shell splinters. After multivariate analysis: low scoring on the GCS and the presence of tomographic abnormalities, midline shift, and diffuse brain swelling.
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Determinação de manganês e zinco em spots protéicos de plasma de tilápia do Nilo (Oreochromis niloticus) por SR-XRF e GFAAS após separação por 2D-PACE

Santos, Felipe André dos [UNESP] 15 June 2010 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:27:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-06-15Bitstream added on 2014-06-13T20:36:06Z : No. of bitstreams: 1 santos_fa_me_botfmvz.pdf: 1235942 bytes, checksum: 7b3f579b06b2874c741bde8ef170587e (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Universidade Estadual Paulista (UNESP) / O presente trabalho teve como objetivo investigar a presença de manganês e zinco em “spots” protéicos de amostras de plasma de tilápia do Nilo (Oreochromis niloticus) obtidos após separação das proteínas por eletroforese em gel de poliacrilamida em segunda dimensão (2D-PAGE) para posterior avaliação qualitativa e quantitativa utilizando fluorescência de raios-X com radiação síncrotron (SR-XRF) e espectrometria de absorção atômica em chama e em forno de grafite (FAAS/GFAAS). As análises dos espectros de fluorescência indicaram a presença de manganês e zinco em quatro e seis “spots” protéicos de plasma, respectivamente. Observou-se que os íons metálicos estão ligados em proteínas com massa molar na faixa de 19 a 70 kDa e com pI na faixa de 4,7 a 6,30. A concentração de manganês e zinco ligados a essas proteínas foi determinada por GFAAS após a mineralização ácida dos spots protéicos, encontrandose concentrações na faixa de 3,40 a 4,20 mg g-1 e 2,30 a 13,90 mg g-1, respectivamente / The aim of the present study was to investigate the presence of manganese and zinc in protein spots in samples of Nile tilapia (Oreochromis niloticus) plasma obtained after protein separation by two-dimensional polyacrylamide gel electrophoresis (2D PAGE) and subsequent qualitative and quantitative determination by synchrotron radiation X-ray fluorescence (SRXRF) and graphite furnace atomic absorption spectrometry (GFAAS). An analysis of the fluorescence spectra indicated the presence of manganese and zinc in four and six plasma protein spots, respectively. It was observed that the metal ions are bound in proteins with molecular weight ranging from 19 to 70 kDa and pI ranging from 4.7 to 6.30. The manganese and zinc concentrations bound to these proteins were determined by GFAAS after acid digestion of protein spots, finding concentrations ranging from 3.40 to 4.20 mg g-1 and 2.30 to 13.90 mg g - 1, respectively
18

Determinação de manganês e zinco em spots protéicos de plasma de tilápia do Nilo (Oreochromis niloticus) por SR-XRF e GFAAS após separação por 2D-PACE /

Santos, Felipe André dos. January 2010 (has links)
Orientador: Pedro de Magalhães Padilha / Banca: Gustavo Rocha de Castro / Banca: Eduardo José de Arruda / Resumo: O presente trabalho teve como objetivo investigar a presença de manganês e zinco em "spots" protéicos de amostras de plasma de tilápia do Nilo (Oreochromis niloticus) obtidos após separação das proteínas por eletroforese em gel de poliacrilamida em segunda dimensão (2D-PAGE) para posterior avaliação qualitativa e quantitativa utilizando fluorescência de raios-X com radiação síncrotron (SR-XRF) e espectrometria de absorção atômica em chama e em forno de grafite (FAAS/GFAAS). As análises dos espectros de fluorescência indicaram a presença de manganês e zinco em quatro e seis "spots" protéicos de plasma, respectivamente. Observou-se que os íons metálicos estão ligados em proteínas com massa molar na faixa de 19 a 70 kDa e com pI na faixa de 4,7 a 6,30. A concentração de manganês e zinco ligados a essas proteínas foi determinada por GFAAS após a mineralização ácida dos spots protéicos, encontrandose concentrações na faixa de 3,40 a 4,20 mg g-1 e 2,30 a 13,90 mg g-1, respectivamente / Abstract: The aim of the present study was to investigate the presence of manganese and zinc in protein spots in samples of Nile tilapia (Oreochromis niloticus) plasma obtained after protein separation by two-dimensional polyacrylamide gel electrophoresis (2D PAGE) and subsequent qualitative and quantitative determination by synchrotron radiation X-ray fluorescence (SRXRF) and graphite furnace atomic absorption spectrometry (GFAAS). An analysis of the fluorescence spectra indicated the presence of manganese and zinc in four and six plasma protein spots, respectively. It was observed that the metal ions are bound in proteins with molecular weight ranging from 19 to 70 kDa and pI ranging from 4.7 to 6.30. The manganese and zinc concentrations bound to these proteins were determined by GFAAS after acid digestion of protein spots, finding concentrations ranging from 3.40 to 4.20 mg g-1 and 2.30 to 13.90 mg g - 1, respectively / Mestre
19

Comparação dos aspectos morfológicos e químicos de esmalte e dentina de dentes decíduos e permanentes / Morphological and chemical aspects comparison between enamel and dentin of permanent and deciduous teeth

Oliveira, Maria Angélica Hueb de Menezes 08 July 2009 (has links)
O objetivo deste estudo in vitro foi avaliar e comparar a microestrutura e a composição mineral do esmalte e da dentina de dentes decíduos e permanentes. Terceiros molares hígidos e segundos molares decíduos foram selecionados e distribuídos aleatoriamente em grupos, de acordo com o método de análise dos substratos utilizado: Microscopia Eletrônica de Varredura (MEV), Espectroscopia de Energia Dispersiva de Raio X (EDX), Difração de Raio X (DRX) e Microscopia Óptica (MO). Foi realizada comparação qualitativa e quantitativa da estrutura dental. As medidas de densidade numérica e diâmetro dos prismas de esmalte/túbulos dentinários e, de espessura do esmalte, dentina e dentina peritubular foram realizadas por meio de fotomicrografias obtidas pela MEV. Os resultados obtidos por meio da SEM foram analisados estatisticamente pelo teste não-paramétrico de Kruskal-Wallis. A quantidade relativa de íons cálcio (Ca) e fósforo (P) foram determinadas por meio de EDX e as fases químicas presentes em ambos os substratos, por análise de DRX. O valor das medidas de espessura observado para o esmalte e dentina dos dentes decíduos foi de 1.14 mm e 3.02 mm, respectivamente. Para os dentes permanentes, obtiveram-se valores de 2.58 mm para o esmalte e 5.95 mm para a dentina. Com relação ao diâmetro da cabeça dos prismas de esmalte, os resultados foram estatisticamente semelhantes para os dentes decíduos e permanentes, demonstrando uma ligeira diminuição do diâmetro da superfície externa para a região próxima a junção amelodentinária (JAD). A densidade numérica dos prismas foi maior nos dentes decíduos, principalmente próximo à JAD, sendo estatisticamente diferente dos valores observados nos dentes permanentes, independente da região analisada. Na análise do diâmetro e densidade numérica dos túbulos dentinários verificou-se semelhança estatística entre os dentes decíduos e permanentes, havendo aumento gradativo do número de túbulos a partir da JAD em direção a região próxima a polpa. A espessura da dentina peritubular, na região próxima a JAD e central foi, respectivamente, 0.91 e 0.59 mm nos dentes decíduos 1.16 e 0.98 mm nos dentes permanentes. A porcentagem de Ca e P foi maior nos dentes permanentes. Observou-se ainda, que a quantidade de colágeno nos dentes decíduos foi aparentemente menor quando analisados por meio da MO. De acordo com os resultados obtidos neste estudo, pode-se concluir que, de maneira geral, os dentes decíduos apresentam menor porcentagem de Ca e P, menor espessura de esmalte e dentina, maior densidade numérica de prismas e dentina peritubular mais delgada quando comparada aos dentes permanentes. / This study evaluated in vitro the microstructure and mineral composition of dental enamel and dentin comparing the permanent teeth with the deciduous teeth. Sound third molars and second primary molars were selected and randomly assigned to the following groups, according to the analysis methods of the substrates performed: Scanning Electron Microscopy (SEM), X-Ray diffraction (XRD), Energy dispersive X-ray spectrometer (EDS) and Optical Microscopy (OP). A qualitative and quantitative comparison of the dental structure was done. The measurements of the number and diameter of prisms/tubules, thickness of enamel, dentin and peritubular dentin were done in SEM photomicrographs. The microscopic findings were analyzed statistically by a non-parametric test (Kruskal- Wallis). The relative amounts of calcium (Ca) and phosphorus (P) were determined by EDS investigation. Phase present in both types of teeth were observed by the XRD analysis. The mean thickness measurements observed in the deciduous teeth enamel and dentin was, respectively, 1.14 mm and 3.02 mm and in the permanent teeth, 2.58 mm and 5.95 mm. The mean rod head diameter in deciduous teeth was statistically similar to that of permanent teeth enamel, and a slightly decrease from the outer enamel surface to the region next to the enameldentine junction was assessed. The numerical density of enamel rods was higher in the deciduous teeth, mainly near EDJ, that showed statistically significant difference. The mean tubules number and diameter in deciduous teeth were statistically similar to that of permanent teeth, and this numerical density increased from the EDJ to the region near the pulp. The mean thickness measurements of peritubular dentin observed in the regions near EDJ and central were, respectively, 0.91 and 0.59 mm for the primary teeth / 1.16 and 0.98 mm for the permanent teeth. The percentage of Ca and P was higher in the permanent teeth. The collagen level was apparently lower in deciduous teeth when analyzed by OP. The primary teeth structure showed a lower level of Ca and P and a thinner enamel and dentin thickness. The deciduous enamel presented higher numerical density of rods. The peritubular dentin was thicker in the permanent teeth.
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Étude de lécoulement dun fluide dans des géométries complexes rencontrées en Génie Chimique par la méthode de Boltzmann sur réseau

Beugre, Djomice 02 June 2010 (has links)
Ce travail de thèse de doctorat, effectué au sein du Département de Chimie Appliquée (au Laboratoire de Génie Chimique, LGC), vise à réaliser létude de lécoulement dun fluide dans des géométries complexes rencontrées en Génie Chimique (les empilages aléatoires et structurés, souvent utilisés dans des colonnes dadsorption et de distillation) par la méthode de Boltzmann sur réseau (Lattice Boltzmann Method, LBM) et à développer un outil numérique de simulation sous la forme dun code de calcul tridimensionnel. Dans le but daméliorer les performances de ces éléments complexes, qui conduisent à une efficacité et une sélectivité accrue des procédés se produisant dans les colonnes de distillation et dadsorption, il est donc intéressant dexaminer avec plus de précision la description des phénomènes de transport se produisant à léchelle locale dans ces milieux. Dans un premier temps, les concepts et les équations macroscopiques qui dérivent de lécoulement dun fluide ont été succinctement passés en revue, ainsi que le modèle de turbulence qui a été utilisé. Nous présentons ensuite, les éléments théoriques de la méthode de Boltzmann sur réseau, après quelques détails sur le modèle Gaz sur réseau, dont elle est dérivée. La méthode de Boltzmann sur réseau se démarque des schémas traditionnels en résolvant numériquement une équation basée sur la physique statistique. Les codes des modèles SRTLBE (équation de Boltzmann sur réseau à un seul temps de relaxation) et MRTLBE (équation de Boltzmann sur réseau à plusieurs temps de relaxation) à trois dimensions, de même que des conditions aux limites convenables ont été écrits dans un langage de programmation, puis validées sur des cas types de la littérature : un écoulement laminaire dans un conduit de section carrée et un écoulement de jet turbulent rectangulaire à 3D. Les codes implémentés dans une grille de calcul ont permis de simuler des écoulements de fluides dans des structures très complexes qui ont été obtenues par une technique expérimentale avancée : la microtomographie à rayons X. Létude dune mousse métallique, dun filtre à charbons actifs et dun filtre de capture daérosols ont été présentés. Les résultats numériques ont été comparés avec succès aux mesures expérimentales et à des corrélations de la littérature. Une autre étude a concerné létude de lécoulement à travers deux feuilles de Mellapak 250 Y. Les champs et contours de vitesse ainsi obtenus ont été soigneusement analysés et commentés à la fois en régime laminaire et en régime turbulent. Les résultats hydrodynamiques ont été comparés avec des mesures expérimentales ainsi quavec des valeurs calculées par des corrélations disponibles dans la littérature. Les modèles existant ont été analysés. Enfin, ces simulations (LBM) ont été comparées à celles effectuées dans les mêmes conditions opératoires, avec le code de calcul classique FLUENT.

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