Rozprawy doktorskie: „X-ray densitometry in medicine”

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Khoo, Benjamin Cheng Choon. "Clinical and phantom-based studies of the validity and value of quantitative radiological hip structural analysis". University of Western Australia. School of Surgery and Pathology, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0189.

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[Truncated abstract] Areal bone mineral density (BMD) is measured routinely in the clinic by a quantitative radiological technique, dual-energy X-ray absorptiometry (DXA). BMD is used widely to assess non-invasively but indirectly the mechanical fragility of bone and consequently is able to predict fracture risk. While BMD correlates well with in vitro measurements of bone strength it does not directly measure a mechanical property; half of incident minimally traumatic fractures in women occur with BMD values above the World Health Organisation defined threshold for osteoporosis. This arises partly because the mechanical strength of bone is dependent on its structural geometry and material strength as well as bone mineral mass. Essentially, bones fracture when load stresses exceed the mechanical capacity of the material to withstand them. The structural geometry (i.e., the amount of bone tissue and its complex three-dimensional arrangement within the macroscopic bone envelope) defines the stresses produced by a given load, while the intrinsic load capacity of the material is defined by the composition and microstructure of the bone tissue itself. Hip structural analysis (HSA) is a technique that elucidates the structural geometric component of bone strength; essentially combining information available from conventional DXA images of the proximal femur with a biomechanical beam model based on the stresses arising in a combination of pure bending and axial compression. A version of HSA has recently been released commercially, and has obtained US Food and Drug Administration approval for its clinical application. ... Given the acknowledged limitations of the HSA method when applied to 2-D projection images, a 3-D approach to structural geometry, using imaging modalities such as pQCT and QCT or a recently introduced version of DXA that mimics QCT, is indicated for the future. With that in mind and the possibility of the anthropometric phantom being adopted for future accuracy and precision assessments, improvements in the design of this phantom are recommended. Studies to better understand and verify Contents v the relevance of the 'local buckling' phenomenon as a structural geometric factor in the genesis of macro-fractures are also recommended. In summary, it is essential that superior (compared to BMD) non-invasively determined clinical predictors of bone fragility leading to fracture be investigated. Structural geometric variables are potential candidates. This has led to consideration of; (i) the need to progress beyond BMD for a more sensitive and specific bone strength measurement; (ii) theoretical advantages of structural geometry over BMD; (iii) limitations of the current HSA technique based on DXA, including those introduced by its restrictive assumptions; (iv) the value of HSA in longitudinal studies, exemplified by the 'normal' but rapid skeletal changes seen in human lactation, with possible implications for an analogous study of the menopause; and (v) an investigation, using a custom-designed anthropometric phantom, of the adaptation of HSA to certain emerging imaging modalities and methods able to resolve bone structural geometry in three dimensions.

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Kelsey, Laurel Anne. "Variance In Percent Body Fat Between And Within Families As Measured By Dual-energy X-ray Absorptiometry". Diss., CLICK HERE for online access, 2004. http://contentdm.lib.byu.edu/ETD/image/etd536.pdf.

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Karlsson, Karin, i Nadja Mortensen. "Precisionsbestämning av bendensitometri". Thesis, Malmö högskola, Fakulteten för hälsa och samhälle (HS), 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-24534.

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International Society for Clinical Densitometry (ISCD) rekommenderar att precisionsbestämning av bentäthetsmätning görs på varje klinik för att bedöma reproducerbarheten. Bentäthetsmätning görs för att diagnosticera osteoporos, följa upp behandling och förutsäga frakturrisk. I studien användes Dual energy x-ray absorptiometry (DXA) för att utföra dubbla mätningar på redan inbokade patienter på klinisk fysiologi, Skånes Universitetssjukhus (SUS), Lund. 105 patienter ingick i studien. Mätningarna utfördes på helkropp, totalhöft, lårbenshals och ländrygg. Helkroppsmätningar ingick i en interindividuell studie och de övriga ingick i intraindividuella studier. Reproducerbarheten uttrycktes som minsta signifikanta skillnaden (LSC), root mean square standardavvikelse (RMS SD) och variationskoefficient (%CV). Reproducerbarheten i studien var god med låga värden för LSC och RMS SD. %CV understeg de av ISCD rekommenderade maxvärdena, vilka är 1,8 % för totalhöft, 2,5 % för lårbenshals och 1,9 % för ländrygg.
It is recommended by the International Society for Clinical Densitometry (ISCD) that every clinic performs a precision assessment of bone densitometry to evaluate the reproducibility. Bone densitometry is used for diagnosis of osteoporosis, to monitor response to treatment and to assess patients’ risk of fractures. Dual energy x-ray absorptiometry (DXA) was used to perform double scans of patients already booked for examination at the section of clinical physiology, Skåne University Hospital (SUS), Lund. 105 patients were included in the study. Measurements were made at whole body, total hip, femoral neck and lumbar spine. The whole body scans were included in an interindividual study, whereas the others were included in intraindividual studies. The reproducibility was expressed as least significant change (LSC), root mean square standard deviation (RMS SD) and coefficient of variation (%CV). The reproducibility in the study was good, with low values for LSC and RMS SD. %CV fell below the maximal values recommended by the ISCD, which are 1,8 % for total hip, 2,5 % for femoral neck and 1,9 % for lumbar spine.

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Meqbel, Manal. "KVALITETSSÄKRING AV BENDENSITOMETRI". Thesis, Malmö universitet, Fakulteten för hälsa och samhälle (HS), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-42833.

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Napolitano, Mary Elizabeth. "Mammographic x-ray unit peak kilovoltage and spectral quality determination using film densitometry". Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/15840.

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Geraki, Kalotina. "Differentiating normal and diseased breast tissue using X-ray fluorescence and energy dispersive X-ray diffraction". Thesis, City University London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274458.

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Oliveira, Márcio Teixeira. "Programa computacional ODR-ATA para densitometria óssea baseado na densitometria radiografica /". Araçatuba, 2014. http://hdl.handle.net/11449/128101.

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Resumo: A densitometria radiográfica é técnica que permite avaliar a densidade óssea, utilizando referências confeccionadas em material inerte (ex. alumínio), principalmente para investigação de alterações ósseas e doenças como a osteoporose. Para aumentar a precisão de técnica, alguns autores propõe o uso de equações matemáticas, como métodos dos mínimos quadrados, teorema de LaPlace e regra de Sarrus o que permitirá obter melhor ajuste da curva característica de absorção aos raios-X pelo objeto de estudo. O uso de tecnologias como Java, gnuplot, broffice calc, todas elas de código aberto, possibilitou-nos o desenvolvimento do software "ODR-ATA", capaz de analisar e processar imagens radiográficas digitais ou digitalizadas e calcular valores de densidade próximos aos valores do objeto em estudo. Atualmente diversas soluções pagas possuem suporte para realizar a densitometria radiográfica. O objetivo deste estudo foi desenvolver uma solução computacional de código livre, para cálculo da densidade óssea a partir da densitometria radiográfica. Para testar o software, foi realizado um experimento a partir de uma tomada radiográfica de uma escada de alumínio de valores conhecidos. Foram feitas 10 repetições e avaliados os degraus 4, 5, 6, 7 e 8 da escada de alumínio. Os resultados obtidos pelo "ODR-ATA" para os degraus 5, 6, 7 e 8 demonstraram uma precisão e exatidão de ordem de 3,64% e 3,63% respectivamente, atestando a validade e confiabilidadena utilização do software na obtenção da densidade óssea obtida pela densidade radiográfica.
Abstract: The radiographic densitometry is the technic that allows the evaluation of bone density, which uses references created in inert material (e.g. aluminium) especially to the investigation of bone modifications and illnesses such as osteoporosis. To increase technical precision some authors suggest the use of mathematical equations, such as the least squares method, Laplace's theorem, and the Rule of Sarrus allowing better results when achieving the adjustment of the curve that is characteristic of X-ray absorption by what is being studied. The usage of technologies such as Java, gnuplot, broffice calc, all of open code, allowed us to develop the software "ODR-ATA", which is capable of analyzing and processing digital radiographic images and of calculating values of density close to the values of the object under study. Recently, various paid solutions have the support to perform radiographic densitometry. The purpose of this study is to develop a computational solution of free code to calculate bone density starting from the radiographic densitometry. In order to test the software I performed an experiment that started with the radiography of an aluminum ladder of unknown values. I performed 10 repetitions and evaluated steps 4,5,6,7, and 8 of the aluminum ladder. The results I achieved with "ODR-ATA" for steps of number 5,6,7, and 8 show a precision of 3,64%% and 3,63% respectively, which attest for the validity and reliability of the software in the discovery of the bone density obtained through the radiographic densitometry
Orientador: Mário Jefferson Quirino Louzada
Banca: Luciana Del Pinoti Ciarlini
Banca: Gilberto Aparecido Coclete
Mestre

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Oliveira, Márcio Teixeira [UNESP]. "Programa computacional ODR-ATA para densitometria óssea baseado na densitometria radiografica". Universidade Estadual Paulista (UNESP), 2014. http://hdl.handle.net/11449/128101.

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A densitometria radiográfica é técnica que permite avaliar a densidade óssea, utilizando referências confeccionadas em material inerte (ex. alumínio), principalmente para investigação de alterações ósseas e doenças como a osteoporose. Para aumentar a precisão de técnica, alguns autores propõe o uso de equações matemáticas, como métodos dos mínimos quadrados, teorema de LaPlace e regra de Sarrus o que permitirá obter melhor ajuste da curva característica de absorção aos raios-X pelo objeto de estudo. O uso de tecnologias como Java, gnuplot, broffice calc, todas elas de código aberto, possibilitou-nos o desenvolvimento do software ODR-ATA, capaz de analisar e processar imagens radiográficas digitais ou digitalizadas e calcular valores de densidade próximos aos valores do objeto em estudo. Atualmente diversas soluções pagas possuem suporte para realizar a densitometria radiográfica. O objetivo deste estudo foi desenvolver uma solução computacional de código livre, para cálculo da densidade óssea a partir da densitometria radiográfica. Para testar o software, foi realizado um experimento a partir de uma tomada radiográfica de uma escada de alumínio de valores conhecidos. Foram feitas 10 repetições e avaliados os degraus 4, 5, 6, 7 e 8 da escada de alumínio. Os resultados obtidos pelo ODR-ATA para os degraus 5, 6, 7 e 8 demonstraram uma precisão e exatidão de ordem de 3,64% e 3,63% respectivamente, atestando a validade e confiabilidadena utilização do software na obtenção da densidade óssea obtida pela densidade radiográfica.
The radiographic densitometry is the technic that allows the evaluation of bone density, which uses references created in inert material (e.g. aluminium) especially to the investigation of bone modifications and illnesses such as osteoporosis. To increase technical precision some authors suggest the use of mathematical equations, such as the least squares method, Laplace's theorem, and the Rule of Sarrus allowing better results when achieving the adjustment of the curve that is characteristic of X-ray absorption by what is being studied. The usage of technologies such as Java, gnuplot, broffice calc, all of open code, allowed us to develop the software ODR-ATA, which is capable of analyzing and processing digital radiographic images and of calculating values of density close to the values of the object under study. Recently, various paid solutions have the support to perform radiographic densitometry. The purpose of this study is to develop a computational solution of free code to calculate bone density starting from the radiographic densitometry. In order to test the software I performed an experiment that started with the radiography of an aluminum ladder of unknown values. I performed 10 repetitions and evaluated steps 4,5,6,7, and 8 of the aluminum ladder. The results I achieved with ODR-ATA for steps of number 5,6,7, and 8 show a precision of 3,64%% and 3,63% respectively, which attest for the validity and reliability of the software in the discovery of the bone density obtained through the radiographic densitometry

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Almqvist, Heléne. "Studies on root hard-tissue demineralization and remineralization measured by ¹²⁵I absorptiometry". Stockholm : Karolinska Institutet, 1993. http://catalog.hathitrust.org/api/volumes/oclc/29572338.html.

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Poissonier, Maud Beatrix. "Iconic normalisation and segmentation in x-ray mammograms". Thesis, University of Oxford, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289122.

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Akachuku, A. E. "Intra-Annual Variation in Wood Density in Gmelina Arborea from X-Ray Densitometry and its Relationship with Rainfall". Tree-Ring Society, 1985. http://hdl.handle.net/10150/261361.

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The variation in wood density within growth rings was determined from X-ray negative images of wood samples of Gmelina arborea. The within-tree and between-tree comparisons showed that no two growth rings had exactly similar patterns of variation in the radial direction. The proportions of wood in four within-ring density classes were estimated. The variations in the proportions of wood in the four classes with age were nonlinear. On the average, the proportion of low density wood decreased with increasing age, while the proportion of high density wood increased with age. Regression analysis testing different curvilinear models showed that 37 to 99 per cent of the variations in the proportions of wood were associated with variations in age. Maximum and minimum ring density were negatively correlated with dry season rainfall. Variations in the proportion of high density wood and mean ring density were not associated with corresponding variation in dry season rainfall. The proportions of low and high density wood, mean ring density, maximum ring density and minimum ring density were not determined by annual rainfall.

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Leclair, Robert J. "X-ray scatter imaging in medicine, model and experimental validation". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0017/NQ57615.pdf.

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Leclair, Robert J. (Robert Joseph) Carleton University Dissertation Physics. "X-ray scatter imaging in medicine; model and experimental validation". Ottawa, 2000.

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Damian, Melissa Feres. "Avaliação do tempo de secagem e da qualidade da imagem de radiografias submetidas a banho em alcool etilico em diferentes concentraçãoes". [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/289007.

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Orientador: Francisco Haiter Neto
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: Com este estudo, teve-se a proposta de avaliar a ação do álcool etílico, nas concentrações de 46ºGL, 70ºGL e 92ºGL, como agente acelerador da secagem de radiografias dentárias, a fim de abreviar o tempo de processamento. Adicionalmente, foi verificado se esse produto poderia causar alterações na dens idade, nas propriedades sensitométricas e na qualidade destas radiografias após um curto período de arquivamento. Para tanto, foram utilizados os filmes radiográficos intra-orais de sensibilidade D (Dspeed), E (E-speed) e E/F (Insight) da Kodak, divididos em grupos de acordo com o uso e a concentração da substância alcoólica. Todos os filmes foram processados manualmente pelo método temperatura/tempo em câmara escura portátil para simular condições clínicas. As radiografias foram submetidas às analises densitométrica e clínica subjetiva, além da construção de curvas características para a obtenção do contraste e da sensibilidade, nos períodos correspondentes a um e seis meses após a realização do experimento, simulando condições de arquivo. Pôde-se observar que o uso do álcool etílico acelerou a secagem das radiografias independentemente do tipo de filme, sendo que o menor tempo foi obtido com a utilização da substância alcoólica de maior concentração. Contudo, os valores de densidade, contraste e sensibilidade foram alterados quando foi utilizado o álcool 70ºGL e o álcool 92ºGL, sendo que este último também foi capaz de alterar a qualidade visual das imagens. Tais alterações puderam ser visualizadas nos dois períodos de avaliação de estudo. Assim, concluiu -se que mesmo que o álcool etílico acelere a secagem das radiografias, sua utilização causou alterações capazes de prejudicar a qualidade da imagem, inclusive após um curto período de arquivamento
Abstract: This study evaluated the action of ethyl alcohol at concentrations of 46ºGL, 70ºGL and 92ºGL as an accelerator of drying of dental radiographs, with a view to reduce the time required for processing. Also, it was observed whether this product might cause alterations in the density, sensitometric properties and quality of these radiographs after a 6- month storage period. For that purpose, intraoral radiographic films D-speed, E-speed and E/F (Insight) of Kodak were employed, which were divided into groups according to the utilization and concentration of the alcoholic substance. All films were developed manually by the time-temperature method in a portable dark room, to simulate the clinical conditions. The radiographs were submitted to densitometric and clinical analyses, besides construction of characteristic curves for achievement of contrast and sensitivity, at periods corresponding to one and six months after accomplishment of the study, simulating conditions of storage. It was observed that the utilization of ethyl alcohol accelerated the drying of radiographs, regardless of the type of film; the shortest time was achieved with utilization of the alcoholic substance of highest concentration. However, the density, contrast and speed of radiographs were altered when concentrations of 70ºGL and 92ºGL were used; being that the latter also altered the visual quality of images. Such alterations could be observed at the two evaluations and study periods. Thus, it was concluded that, even though the ethyl alcohol may accelerate the drying of radiographs, its utilization caused alterations able to impair the quality of image, even after a short period of storage
Doutorado
Radiologia Odontologica
Doutor em Radiologia Odontológica

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Kulkarni, Radhika. "Locating regions of interest prior to X-ray imaging using stereo-photogrammetry". Master's thesis, University of Cape Town, 2011. http://hdl.handle.net/11427/11284.

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Evershed, Anthony N. Z. "A multi-material approach to beam hardening correction and calibration in X-ray microtomography". Thesis, Queen Mary, University of London, 2013. http://qmro.qmul.ac.uk/xmlui/handle/123456789/8393.

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X-ray microtomogaphy is a non-clinical, non-destructive, and quantitative technique for determining three-dimensional mineral concentration distributions in variably radiolucent samples with a spatial resolution on the micron scale. For reasons of practicality, particularly for longterm studies, it is often not possible or desirable to utilise a monochromatic X-ray source and so microtomography using a conventional impact-source X-ray generator to produce a polychromatic photon beam is carried out instead. The use of photons of multiple energies causes the production of projection artefacts arising from preferential absorption, which impair the greyscale accuracy of the resulting reconstruction and the material concentration measurements that are derived from the linear attenuation coefficients (LACs). The purpose of the project described in this thesis is to identify weaknesses in the current method of beam hardening correction and to develop and test a tomographic calibration and projection processing method which may demonstrably improve the quality of current beam hardening correction methods as used with the MuCAT microtomography equipment, which provides a worldclass impact-source microtomography research and production facility at Barts and The London School of Medicine and Dentistry. An overview of the physical basis of X-ray computed tomography and X-ray microtomography is given from first principles, and examples of quantitative applications of the techniques, which generally depend on accurate reconstruction of linear attenuation coefficient values, are discussed. The major sources of artefacts in X-ray microtomography are discussed, particularly those with a direct impact on reconstructed linear attenuation coefficient values. Beam hardening is identified as an error source of particular interest, with secondary research on the effects of any beam hardening correction method on the severity of Compton scatter artefacts, and a critical review is carried out of historical attempts to reduce or mitigate these artefacts, particularly the single-material parameter-optimisation approach in service at the beginning of the research project. A ‘carousel’ test piece comprising multiple attenuators of multiple materials along with attenuation optimisation software based on varying multiple system parameters in order to extend the functionality and usability of the existing correction model, and qualitative results have so far been gathered suggesting the use of this system over the pre-existing attenuation wedge and parameter-optimisation method. A study of the effects of tuning the photon energy to which calibrations are made is carried out, showing improved linear attenuation coefficient recovery at a higher energy than was previously believed to be optimal, and a significant effect arising from X-ray generator target evaporation leading to spatial changes and time-dependence of the target thickness parameter is measured, suggesting that automated calibration as a standard part of the measurement process is required. A stability experiment is carried out using this method in order to examine the possibility of inconsistency resulting from ageing of the filament cathode, which is found not to significantly impact the quality of results. An immersion tank is developed in order to ensure beam hardening correction validity in the case of dual-material specimens where a radiodensity-matching fluid can be provided and the sample is suitable for immersion. Experimental comparison using a commercial beam hardening calibration device as the specimen reveals significantly improved hydroxyapatite concentration measurement recovery. An in-scatter experiment was carried out on the immersion tank, and it was found that there was a significant scatter contribution when the tank was filled in the case where the sample thickness is much less than the tank thickness. Proposals are presented for further work to improve reconstruction quality through of scatter reduction techniques in impactsource microtomographic systems, and to utilise the immersion tank for in situ chemical erosion experiments. The effects of the improvements to the beam hardening process are demonstrated using a biological specimen to demonstrate qualitative changes in reconstruction, particularly in improved dark levels surrounding the specimen. A second experiment is carried out in order to test the reproducibility of results, which is found to be improved by approximately four times over the same dataset corrected using the pre-existingbeam-hardening calibration method.

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Ferreira, Angel Thiane Boschiero. "Avaliação da estrutura anatômica e da densidade aparente do lenho e do carvão de árvores de Eucalyptus sp. e de Corymbia sp". Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-09122013-165413/.

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A madeira é considerada como estratégica como produto base para inúmeros setores e segmentos da economia mundial e nacional, para a produção de móveis, pisos, construção, celulose, papel e outros produtos e, ainda, no setor energético, para a produção de álcool, e, em especial no Brasil, para o carvão vegetal, em siderúrgicas. O carvão da madeira de florestas plantadas de eucaliptos traz um maior benefício ao país, pela redução da pressão da exploração da madeira das florestas nativas. A transformação da madeira em carvão ocorre através de tratamento térmico, compreendendo diversas fases de aquecimento, com consequente alteração da madeira, como a perda de água, contração, degradação e ruptura da parede celular dos seus elementos anatômicos. Neste aspecto, são incipientes os estudos das alterações da anatomia da madeira dos eucaliptos resultantes do processo de carbonização e sua aplicação na melhoria da estrutura e da qualidade do carvão. Pelo exposto, o presente trabalho tem como objetivo estudar as alterações da estrutura anatômica, densidade aparente e variação dimensional da madeira e do carvão de árvores de 19 clones/espécies/híbridos de Eucalyptus e Corymbia, de plantações da Aperam Bioenergia Jequitinhonha, da região do Vale do Jequitinhonha/MG. Após a análise anatômica macroscópica e de densitometria de raios X, assim como as medições dimensionais de todos as amostras, a madeira das árvores de Eucalyptus e Corymbia foi submetida ao tratamento térmico de carbonização (450ºC) e, na sequência, aplicados métodos de análise da anatomia microscópica, de densitometria de raios X e de avaliação da contração/redução dimensional. Os resultados das análises anatômicas mostraram que os vasos do lenho próximos da medula e da casca são de menor diâmetro-maior frequência e maior diâmetro-menor frequência, respectivamente, com os clones de maior densidade com menor dimensão-maior frequência dos vasos. A análise microscópica comparada da madeira e do carvão mostrou a alteração dos vasos de formato circular a ovalado-oblongo, redução do diâmetro tangencial e aumento da frequência. Da mesma forma, os resultados indicaram que a densidade aparente da madeira é, de modo geral, 50% maior do que a do carvão. Os clones de madeira e de carvão de maior densidade aparente foram os de C. citriodora e o de C. toreliana x C. citriodora; os de menor densidade aparente foram os de E. urophylla x (E. camaldulensis x E. grandis) e de E. urophylla. Verificou-se, ainda, que a redução/contração da madeira na carbonização foi maior nos sentidos tangencial (26,06%) e radial (15,94%) e nos clones de maior densidade aparente.
Wood is considered as a strategic base product for numerous industries and sectors of the world and national economy, for the furniture production, flooring, construction, pulp, paper and other products, and also in the energy sector for the production of alcohol, and especially in Brazil, to produce charcoal for the steel manufacture. The charcoal from planted forests of eucalyptus brings a greater benefit to the country, by reducing the pressure of the logging of native forests. The transformation of wood charcoal occurs through heat treatment comprising various stages of heating, with consequent alteration of the wood, such as water loss, shrinkage, and degradation of the cell wall rupture of their anatomical elements. In this aspect, are incipient the studies of the wood anatomy changes of eucalypts resulting from the carbonization process and its application in improving the structure and quality of the charcoal. For these reasons, the present work aims to study the changes of anatomical structure, apparent density and dimensional change of the wood and the charcoal from trees of 19 clones/species/hybrids of Eucalyptus and Corymbia plantations from Aperam Bioenergy Jequitinhonha, coming from the region Jequitinhonha Valley/MG. After the anatomical analysis macroscopic and X-ray densitometry, as well the dimensional measurements of all the samples, the wood of Eucalyptus and Corymbia trees was subjected to the heat treatment of carbonization (450° C) and, subsequently, applied methods for the analysis of microscopic anatomy, X-ray densitometry and evaluation of contraction/dimensional reduction. The analysis results showed that the anatomical vessels near the spinal wood and bark are in smaller diameter, higher - frequency and larger-diameter lower frequency, respectively, and clones with higher density has higher frequency and smaller vessels. Microscopic analysis compared the wood and charcoal showed the change in vessels circular shape oblong-oval, reducing the diameter and increasing shear rate. Likewise, the results indicated that the apparent density of the wood is generally 50% greater than that of charcoal. The clones with the highest density were C. citriodora and C. toreliana x C. citriodora, the lower density were E. urophylla x (E. grandis x camaldulensis) and E. urophylla. It was also found that the reduction/shrinkage of the wood after carbonization was greater in the tangential directions (26.06 %) and radial (15.94 %) and in the clones of higher apparent density.

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Esmail, Mohammed. "Towards improving the Statscan X-ray image quality through sliding mode control of the C-arm". Master's thesis, University of Cape Town, 2012. http://hdl.handle.net/11427/3382.

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This dissertation investigates methods for improving the image quality of a digital radiography system. The Lodox Statscan™ X-ray system provides a full-body scanned image for initial diagnosis. The system is driven by a permanent magnet linear motor (PMLM) controlled by a cascaded proportional-proportional integral controller (P-PI). Transient errors in the trapezoidal motion profile of the scanning C-arm may cause mismatches between the detector and the collimated beams from the X-ray source. This results in a partial degradation of image quality. The Statscan™ X-ray system was investigated and the following constraints were identified: The scanning time is limited to 13 seconds and the maximum scan length is limited to 1.8 m. Since it was not possible to obtain the Lodox Statscan™ dynamics model, because of the similarity, a characteristic model was then developed using a DC motor in order to investigate the control dynamics. It is not advisable for a designer to manipulate the controllers on commercial machines except for changing the parameters for tuning. Therefore, a P-PI controller and a proportional-integral sliding mode controller (P-ISMC) as well as a Boundary Layer variant (P-ISMC+BD) were designed for fair comparison purposes. Root locus, Bode diagrams and integral sliding mode control methods, respectively, were used to design the P-PI and P-ISMC controller groups. Each controller consists of an inner loop and an outer position loop. Proportional integral (PI) and integral sliding mode controllers (ISMC) were used for the inner loop. The two inner loop controllers were tuned, and then tested, before cascading them with the outer position loop. The simulation and experiments were conducted to compare each controller’s performance on step set-point tracking, trapezoidal motion profile tracking, the time transient’s specifications and robustness against disturbances. In order to test image quality, 27 distance profiles were generated from P-PI, P-ISMC and P-ISMC+BD. In addition, four images captured by the Statscan™ were also selected. A time delay integrator (TDI) simulator was used on the distance profiles and the four images to generate 108 distorted image profiles.

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Al, Arif S. M. M. R. "Fully automatic image analysis framework for cervical vertebra in X-ray images". Thesis, City, University of London, 2018. http://openaccess.city.ac.uk/19184/.

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Despite the advancement in imaging technologies, a fifth of the injuries in the cervical spine remain unnoticed in the X-ray radiological exam. About a two-third of the subjects with unnoticed injuries suffer tragic consequences. Based on the success of computer-aided systems in several medical image modalities to enhance clinical interpretation, we have proposed a fully automatic image analysis framework for cervical vertebrae in X-ray images. The framework takes an X-ray image as input and highlights different vertebral features at the output. To the best of our knowledge, this is the first fully automatic system in the literature for the analysis of the cervical vertebrae. The complete framework has been built by cascading specialized modules, each of which addresses a specific computer vision problem. This dissertation explores data-driven supervised machine learning solutions to these problems. Given an input X-ray image, the first module localizes the spinal region. The second module predicts vertebral centers from the spinal region which are then used to generate vertebral image patches. These patches are then passed through machine learning modules that detect vertebral corners, highlight vertebral boundaries, segment vertebral body and predict vertebral shapes. In the process of building the complete framework, we have proposed and compared different solutions to the problems addressed by each of the modules. A novel region-aware dense classification deep neural network has been proposed for the first module to address the spine localization problem. The proposed network outperformed the standard dense classification network and random forestbased methods. Location of the vertebral centers and corners vary based on human interpretation and thus are better represented by probability maps than single points. To learn the mapping between the vertebral image patches and the probability maps, a novel neural network capable of predicting a spatially distributed probabilistic distribution has been proposed. The network achieved expert-level performance in localizing vertebral centers and outperform the Harris corner detector and Hough forest-based methods for corner localization. The proposed network has also shown its capability for detecting vertebral boundaries and produced visually better results than the dense classification network-based boundary detectors. Segmentation of the vertebral body is a crucial part of the proposed framework. A new shapeaware loss function has been proposed for training a segmentation network to encourage prediction of vertebra-like structures. The segmentation performance improved significantly, however, the pixel-wise nature of proposed loss function was not able to constrain the predictions adequately. To solve the problem a novel neural network was proposed which predicts vertebral shapes and trains on a loss function defined in the shape space. The proposed shape predictor network was capable of learning better topological information about the vertebra than the shape-aware segmentation network. The methods proposed in this dissertation have been trained and tested on a challenging dataset of X-ray images collected from medical emergency rooms. The proposed, first-of-its-kind, fully automatic framework produces state-of-the-art results both quantitatively and qualitatively.

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Dixon, Toinette-Lee. "Implementation and evaluation of a bony structure suppression software tool for chest X-ray imaging". Master's thesis, University of Cape Town, 2012. http://hdl.handle.net/11427/11993.

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This project proposed to implement a bony structure suppression tool and analyse its effects on a texture-based classification algorithm in order to assist in the analysis of chest X-ray images. The diagnosis of pulmonary tuberculosis (TB) often includes the evaluation of chest X-ray images, and the reliability of image interpretation depends upon the experience of the radiologist. Computer-aided diagnosis (CAD) may be used to increase the accuracy of diagnosis. Overlapping structures in chest X-ray images hinder the ability of lung texture analysis for CAD to detect abnormalities. This dissertation examines whether the performance of texturebased CAD tools may be improved by the suppression of bony structures, particularly of the ribs, in the chest region.

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Kälvesten, Johan. "Automatic image analysis for decision support in rheumatoid arthritis and osteoporosis". Doctoral thesis, Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-113680.

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Low-energy trauma and fragility fractures represent a major public health problem. The societal cost of the fragility fractures that occurred in Sweden 2010 has been estimated at €4 billion. In rheumatoid arthritis (RA), patient outcomes have improved greatly in recent years. However, the therapeutic decision making is still hampered by a lack of effective validated biomarkers. The cost of RA in Sweden 2010 has been estimated at €600 million, of which biologic drugs was €180 million. Digital X-ray radiogrammetry (DXR) is a method to measure bone mineral density (BMD) in the metacarpals of the hand. It can be applied opportunistically in several workflows where a person is already at an X-ray machine, including fracture repositioning follow up, mammography screening and hand imaging in RA. This thesis explored DXR-BMD as a marker to identify individuals who would benefit from anti-osteoporotic treatment, change rate of DXR-BMD as a biomarker in RA and under what conditions historical X-ray images can be used to estimate DXR-BMD. An automated method for measurement of joint space width in metacarpophalangeal and interphalangeal joints was also developed and evaluated as a biomarker in RA. Low DXR-BMD was predictive for hip fractures and predicted fragility fractures to a comparable degree as other BMD measurement sites. Rapid decrease of DXR-BMD was a strong and independent predictor for progression of radiographic damage in RA when manual radiographic progression scores were not available. Change of metacarpal joint space width was a statistically significant but weak predictor of joint space narrowing score progression. Guidelines and considerations for use of historical X-ray radiographs for DXR-BMD measurements in clinical trials have been developed and published.

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Sechopoulos, Ioannis. "Investigation of physical processes in digital x-ray tomosynthesis imaging of the breast". Diss., Atlanta, Ga. : Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/22589.

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Wilkinson, Steven. "Semi-automated measurement from X-ray diffraction of connective tissues with an application to the uterine cervix during pregnancy". Thesis, University of Aberdeen, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274847.

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X-ray diffraction from soft tissues can give information about collagen contained within the tissue matrix. Semi-automated analysis software was developed for diffraction pattern analysis. Diffraction patterns are often very different for different tissues and can be relatively indistinct and have more than tow diffractions maxima positions. A marked centre and the first two maxima positions provide distance values. Three different materials containing collagen were used and the variation of distances used to obtain a measure of accuracy. The peaks could be found on the images used to an accuracy of about 4% relating to a precision measured on the originals film of about 4mm. Accuracy of the methods varies according to the diffraction pattern and can vary from 2% to 7% accuracy. A preliminary study was carried out to assess the uterine cervix at various stages during pregnancy using a rat model. Resulting diffraction patterns were scanned to resolution of 105mm per pixel, to create a digital image. Data extracted from the image around a circle passing through the first two peaks located has a Gaussian functional fit applied. There were statistically significant changes towards a more vertical (circumferential to the cervix canal) orientation between pairs of measurements both in separation and in bisector angle measurements. The separation between orientations corresponding to the two diffraction maxima appear to decrease during pregnancy with two pairs of values giving significant changes. Fitted Gaussian curves with the larger sigma value demonstrated a marked increase in width at about the time of parturition. Conclusions from the results on testing the software and using the methods on a real practical study indicate that the software methods developed were easy to use, reasonably accurate and obtain information fairly rapidly from individual images of diffuse peaks.

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Deodhar, Atulya A. "Development of dual energy X-ray absorptiometry to measure hand bone mineral content for the assessment of rheumatoid arthritis". Thesis, University of Bath, 1996. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362240.

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Ahmad, Tashfeen. "Diabetic osteopathy : a study in the rat /". Stockholm, 2003. http://diss.kib.ki.se/2003/91-7349-615-4/.

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Solbrig, Konrad [Verfasser]. "Applied investigations on wood-based composites in the context of X-ray densitometry : Angewandte Untersuchungen an Holzwerkstoffen im Zusammenhang mit der Dichtemessung mittels Röntgenstrahlung / Konrad Solbrig". Hamburg : Staats- und Universitätsbibliothek Hamburg Carl von Ossietzky, 2019. http://d-nb.info/1226289029/34.

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Te, Riele Julian Bernard. "The relationship between chest X-ray findings, bacterial load and treatment-related outcomes in persons with extensively drug resistant TB". Master's thesis, University of Cape Town, 2014. http://hdl.handle.net/11427/13289.

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Multi-drug resistant tuberculosis (MDR-TB) was first recognized in the 1990s with an increase in caseload of eighty-two percent between 2000 and 2007. Extensively drug-resistant tuberculosis (XDR-TB), a more difficult and more expensive form of TB to treat with poorer outcomes, emerged in South Africa in 2006. The prevalence of XDR-TB is likely to be underestimated in South Africa as a result of incomplete detection and notification. In peri-urban areas like Khayelitsha where there are high rates of HIV, TB and poverty, the prevalence of MDR-TB is estimated at 51/100 000. A significant proportion of these cases are indeed undetected pre-XDR-TB (MDR and resistance to either a fluoroquinolone or a 2nd line injectable drug) and XDR (MDR and resistance to both fluoroquinolones and any one of the 2nd line injectable drugs) cases with inadequate access to drug sensitivity testing. Treatment outcomes of XDR-TB have been variable with countries like Peru showing a 60% overall cure (or completed treatment) rate, and studies in KwaZulu Natal in South Africa showing much poorer outcomes. The reasons for the poor outcomes in XDR-TB remain unclear. We are continuing to investigate the role of strain-type and several other factors including nutritional status, degree of drug resistance, HIV status and drug regimens in determining outcomes. There is a paucity of literature describing the chest X-ray (CXR) findings in patients with XDR-TB, and whether disease extent is related to treatment outcomes and the evolution of resistance remains unclear. It has been shown that patients with radiological extensive drug-sensitive TB have higher initial sputum mycobacterial loads and take a longer time to sputum conversion than those without . The extent of disease on the CXR at baseline has been used as a tool to inform and predict the need for infection control measures, treatment duration, and outcomes. The time-to-positivity (TTP) of mycobacterium tuberculosis in a liquid medium culture has become a validated indicator of bacterial sputum load and indeed a surrogate bio-marker of treatment response to anti-tuberculosis drugs. The relationships between mycobacterial sputum load, radiological disease and treatment outcomes have been studied in drug-sensitive TB, but little is known about XDR-TB.

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Latti, Emari (Emarencia Martha). "Development of a digital X-ray-imaging system at the National Accelerator Centre". Thesis, Stellenbosch : Stellenbosch University, 2000. http://hdl.handle.net/10019.1/51685.

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Thesis (MSc)--Stellenbosch University, 2000.
ENGLISH ABSTRACT: A digital portal X-ray imaging system was developed to replace the radiographic X-ray films currently used for patient position verification at the National Accelerator Centre (NAC) proton therapy facility. The main advantage of a digital system is the short time in which the image can be obtained. Other advantages include optimisation of the image display, effective archiving of the digital images, access from various locations through data networks, and lower operational costs. The digital system described in this thesis consists of a Gd202S:Tb scintillator screen for converting X-rays to visible light, a protected aluminum front silvered mirror to direct the light to a Charge Coupled Device (CCD) camera for capture and a personal computer for data acquisition, processing and display. Compared with other digital imaging systems, this is a simple, compact and affordable system. The properties of the various components were investigated. The Rarex G-130 (Gd202S:Tb) scintillation screen was chosen for its good spatial resolution, high emission efficiency and good matching between the spectral emission wavelength peak and the quantum efficiency of the CCD camera. The spatial resolution measured for the system with a field of view (FOV) of 290 x 190 mnr' is 1.3 lp/mm, which can be improved by increasing the CCD chip resolution or decreasing the field of view, since the CCD camera limits the spatial resolution. Intrinsic detector noise determines the lower limit of the dynamic range of the detector and is reduced by cooling the CCD camera. A dark current exposure is subtracted from the image to remove the bias signal and background signal level mainly caused by thermal noise. Photon noise, beam in-homogeneity and efficiency variations across the CCD chip are removed by a flat field correction. The digital images obtained with this system compare very well with the currently used radiographic film images and they are satisfactory for the purpose of patient position verification. Using the digital system it is possible to reduce the patient dose by 19 % and still obtain satisfactory image quality.
AFRIKAANSE OPSOMMING: 'n Digitale X-straalafbeeldingstelsel is ontwikkel om die radiografiese X-straalfilm wat tans gebruik word vir die kontrolering van die pasientposisionering voor die toediening van protonterapie by die Nasionale Versnellersentrum, te vervang. Die voordeel van die digitale sisteem is dat die beelde feitlik onmiddellik beskikbaar is. Verdere voordele sluit die optimisering van die vertoon van beeldkontras, effektiewe liassering, vinnige bereik deur datanetwerke en lae lopende kostes in. Die digitale sisteem beskryf in die tesis bestaan uit 'n gadolinium oksi-sulfied (Gd202S:Tb) sintillasieskerm wat X-strale omskakel na sigbare lig, 'n eerste-oppervlak aluminiumspieël wat die lig na 'n digitale kamera (CCD kamera) weerkaats en In persoonlike rekenaar vir dataverwerwing, verwerking en vertoon. Vergeleke met ander digitale stelsels is hierdie digitale beeldingstelsel eenvoudig, kompak en bekostigbaar. Die eienskappe van die verskillende komponente van die stelsel is ondersoek. Die Rarex G- 130 (Gd202S:Tb) sintillasieskerm IS gekies vanweë goeie resolusie, hoë emissiedoeltreffendheid en die hoë omsettingsdoeltreffendheid van die digitale kamera by die spektrale emissiegolflengte van dié sintillasieskerm. Die ruimtelike oplosvermoë van die stelsel is bepaal met In veldgrootte van 290 x 190 mnr' as 1.3 lynpare per millimeter. Die ruimtelike oplosvermoë kan verhoog word deur die kameraresolusie te verhoog of die veldgrootte te verklein, omdat die resolusie van die kamera tans die oplosvermoë van die stelsel beperk. Intrinsieke ruis van die detektor beperk die onderste grens van die dinamiese reikwydte van die detektor en kan verminder word deur die kamera te verkoel. 'n Donkerstroom-beeld word van die X-straalbeelde afgetrek om die voorspanningsein en die agtergrondsein, wat hoofsaaklik veroorsaak word deur termiese ruis, te verwyder. Ruis wat ontstaan as gevolg van fluktuasies in die aantal fotone, nie-homogeniteite in die bundel of variasie van die sensitiwiteit in die skerm word verwyder met behulp van 'n plat vlak beeld. Die digitale beelde verkry met die stelsel vergelyk goed met die beelde wat tans op film geneem word en die beeldkwalitiet is voldoende vir die kontrolering van die pasientopstelling. Dit is moontlik om die pasiëntdosis met 19 % te verminder en steeds voldoende beeldkwaliteit te verkry.

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MARTINS, ELAINE W. "Desenvolvimento e aplicação de um simulador pediátrico craniano para dosimetria em tomografia computadorizada". reponame:Repositório Institucional do IPEN, 2016. http://repositorio.ipen.br:8080/xmlui/handle/123456789/26608.

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Submitted by Marco Antonio Oliveira da Silva (maosilva@ipen.br) on 2016-08-26T10:42:03Z No. of bitstreams: 0
Made available in DSpace on 2016-08-26T10:42:03Z (GMT). No. of bitstreams: 0
Para avaliar os níveis de exposição e a dose absorvida em pacientes submetidos a exames de tomografia computadorizada, TC, é necessário calcular os índices de dose em medições com um simulador de PMMA, ou cheio de água. O simulador deve ser capaz de reproduzir as características de absorção e espalhamento do corpo ou parte do corpo humano em um campo de radiação. As grandezas específicas em TC: índice de kerma livre no ar (Ca,100), índice de kerma no ar ponderado (CW), índice de kerma no volume total (Cvol) e produto kerma no ar-comprimento (PKL) devem ser determinadas e comparadas com os níveis de referência já existentes na literatura. Neste trabalho foi desenvolvido um simulador pediátrico craniano, já que no Brasil os níveis de referência para diagnósticos (NRDs) disponíveis foram determinados baseados em um simulador padrão adulto. O simulador desenvolvido inovou em sua construção apresentando materiais que simulam a calota craniana em osso cortical (alumínio) e osso esponjoso (PVC). O seu interior foi preenchido com água destilada. As dimensões foram escolhidas de acordo com as recomendações da Organização Mundial da Saúde e do International Commission on Radiation Units, para o tamanho da cabeça de uma criança de 0 a 5 anos: 160 mm de diâmetro e 155 mm de altura. A calota craniana tem uma espessura de 4 mm e diâmetro interno de 111,9 mm. Para avaliar seu comportamento foram realizados testes em laboratórios e em feixes clínicos. Os resultados apresentaram uma atenuação de até 23% na utilização dos materiais que simulam a calota craniana evidenciando que os valores adotados para os cálculos de NRD podem estar superestimando a dose recebida por pacientes pediátricos. Percebe-se que a dose recebida em exames de crânio apresenta uma distribuição diferente por ser parcialmente atenuada e/ou retroespalhada pela calota craniana, o que não é considerado ao se utilizar o simulador constituído apenas de PMMA.
Tese (Doutorado em Tecnologia Nuclear)
IPEN/T
Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP

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Júnior, Claudio Roberto Anholetto. "Dendroecologia e composição isotópica (δ13C) dos anéis de crescimento de árvores de Cedrela odorata, Meliaceae, na Caatinga e Mata Atlântica do estado de Sergipe, Brasil". Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-30102013-105715/.

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O Estado de Sergipe, apesar de ser o menor entre os estados da confederação, apresenta uma grande diversidade de ambientes. Sob o regime climático litorâneo, florestas tropicais prosperam contanto com grande disponibilidade hídrica, enquanto no interior, formações florestais rústicas crescem em um dos ambientes mais secos do Brasil. A dendrocronologia trata-se de uma ciência fundamentada em uma série de princípios, que devem ser atendidos em sua totalidade, e assim o foram nos diversos ambientes de Mata Atlântica/Caatinga sergipanos. Esta ciência, capaz de proporcionar estimativas acuradas da idade das árvores, sua dinâmica na comunidade, e relação com o clima, foi utilizada neste trabalho em busca de seu objetivo, tido como o estudo da espécie Cedrela odorata, e a influência de diversos fatores ambientais sob seu crescimento diamétrico, periodicidade de formação dos anéis de crescimento e para o desenvolvimento de cronologias a partir dos mesmos. A pesquisa foi desenvolvida em três diferentes sítios, localizados nos extremos geográficos do Estado de Sergipe, sob o domínio de atuantes climáticas díspares. Amostras de lenhos foram retiradas no DAP do tronco para as avaliações dendrocronológicas, de densitometria de raios X e isotópicas. Verificou-se a presença de grande sazonalidade climática e fenológica em todos os ambientes. Observou-se que a formação dos anéis de crescimento destas árvores foi regulada principalmente pela precipitação da estação corrente de crescimento e pela temperatura da estação anterior à esta, indicando que possuem potencial para estudos paleoclimáticos. A análise isotópica exibiu a tendência de diminuição dos valores de ?13C ao longo dos anos e o aumento dos valores da Eficiência do uso da água (iWUE). Houve diferença significativa no ritmo de crescimento do tronco das árvores entre os diferentes sítios, porém em todos eles a formação anual dos anéis de crescimento e sua relação com o clima foi confirmada, principalmente para o inédito ambiente de Caatinga, que agora pode ser inserido no cenário internacional de estudos dendrocronológicos.
The State of Sergipe, despite being among the smallest states of the confederation, has a wide range of environments. Under the regime coastal climate, rainforests thrive provided with great water availability, while inside, rustic forest formations grow in one of the driest environments in Brazil. Dendrochronology it is a science based on a series of principles that must be attended in its totality, and so they were in the different Tropical Rainforest/Caatinga environments in Sergipe. This science, capable of providing accurate estimates of trees age, their community dynamics, and relation to climate, was used in this work in pursuit of his goal, considered to be the study of the species Cedrela odorata, and the influence of several environmental factors on its diameter growth, timing of formation of the growth rings and for developing chronologies out of the same. The research was conducted at three different sites, located in the geographical extremes of the State of Sergipe, in the grip of disparate operating climate. Sample logs were removed from the trunk\'s DBA to the dendrocrhonological assessments, X-ray densitometry and isotopic. There was the presence of large climatic and phenological seasonality in all environments. It was observed that these trees growth rings formation is governed mainly by the current station precipitation and the prior station temperature, indicating that they have potential for palaeoclimatic studies. Isotopic analysis showed a trend of decreasing ?13C values over the years and the values increased efficiency of water use (IWUE). There was significant difference in the rate of growth of the tree trunk between the sites, but in all of them the formation of annual growth rings and their relationship with climate was confirmed, especially to the unprecedented Caatinga environment, which now can be inserted into the international scenario of dendrochronological studies.

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Labib, Sameh A. "The determination of the mechanical axis of the knee on a short X-ray : a new radiographic technique". Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=56999.

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Most authors recommend drawing the mechanical axis on a three-foot (90 cm) full leg length x-ray for accurate assessment of knee alignment. Three foot x-rays are difficult to perform and reproduce and involve undue radiation to the gonads. The purpose of this project is to propose a new radiographic technique whereby the mechanical axis of the knee can be assessed on a short A/P x-ray of the entire tibia.
Methodology. 21 normal adults and 25 patients with malaligned knees were investigated in the following manner--the patient was x-rayed in standing position with the legs positioned exactly parallel to one another and vertical to the floor. Under these circumstances, the ankles were apart by a distance (distance F$ sb1$) equal to the distance between the femoral heads (distance F). The mechanical axes were hence parallel to one another and parallel to the long axis of the x-ray cassette and vertical to the floor. Two separate x-rays were taken, a three-foot (90cm) long x-ray and a short x- ray of the entire tibia. The mechanical axis was determined on the 90 cm, three-foot long x-ray.
A vertical line drawn on the short x-ray starting from the centre of the ankle and extended upwards and parallel to the long axis of the x-ray cassette could accurately identify the mechanical axis of the knee using either technique. (Fig. 1)
The technique has been called the "Parallel Mechanical Axes X-ray Technique". It has been validated and it will be demonstrated that such an x-ray technique: (1) Standardizes positioning of the lower extremities. (2) Is a precise, easily controllable method to assess knee alignment. (3) A short x-ray of the entire tibia is sufficient, thus reducing the cost of x-rays by 50%. (4) Obviates the need to visualize the pelvis thus minimizing net radiation exposure. (5) May be used in clinics and smaller hospitals, since it requires simple and inexpensive x-ray facilities.

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Castro, Vinícius Resende de. "Aplicação de métodos não destrutivos na avaliação das propriedades físicas do lenho de árvores de Pinus caribaea var. hondurensis Barr. et Golf. e Tectona grandis (L.f.)". Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-13092011-112235/.

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A aplicação de métodos não destrutivos (MND) invasivos - extração de amostras do lenho do tronco das árvores com sondas metálicas - e não invasivos análise do lenho diretamente no tronco - permite a avaliação da qualidade do lenho, dos defeitos internos e sua aplicação como madeira sólida. No presente trabalho são aplicados os MND invasivo (densitometria de raios X) e não invasivo (tomógrafo de impulso) na análise do lenho do tronco de 18 árvores de Pinus caribaea var. hondurensis e 18 de Tectona grandis, com 18 e 52 anos, respectivamente. Os resultados permitem concluir que a (i) estrutura anatômica macroscópica do lenho e dos anéis de crescimento descrita é característica das coníferas (Pinus) e das folhosas (Tectona) e similar à apresentada na literatura; (ii) as imagens tomográficas da seção transversal do lenho indicam um bom estado de sanidade (Pinus) e regiões afetadas do lenho (Tectona); a velocidade de onda é maior na região interna em relação à externa (Pinus) e maior em um dos raios, decrescendo em direção à medula e do raio oposto (Tectona) do lenho, e permite agrupar as árvores em 4 (Pinus) e 6 (Tectona) classes; observa-se a correlação do diâmetro do tronco com o tempo médio da velocidade de onda; (iii) os perfis diametrais de densidade aparente e básica do lenho indicam aumento da medula para a casca e estabilização no lenho externo; os perfis radiais de densidade aparente permitem a precisa demarcação dos anéis de crescimento anuais; os valores médios de densidade agrupam as árvores em 3-2 (Pinus) e 6-5 (Tectona) classes não se observando correlação com o diâmetro do tronco; (iv) os perfis diametrais de teor de umidade do lenho indicam uma diminuição da medula para a casca e estabilização no lenho externo; permitem agrupar as árvores em 3 (Pinus) e 5 (Tectona) classes e não se correlacionam com o diâmetro do tronco; (v) o coeficiente de correlação de Pearson indicou valores negativos e não significativos entre a velocidade de onda e a densidade aparente e básica do lenho (Pinus) e entre a velocidade de onda e a densidade básica do lenho (Tectona); positiva e não significativa para o teor de umidade (Pinus) e positiva e não significativa para o teor de umidade e a densidade aparente (Tectona); negativa entre o teor de umidade e a densidade aparente e básica do lenho; (vi) a velocidade média de onda no lenho é menor e com maior variação das velocidades médias mínima e máxima em Tectona, em relação às árvores de Pinus; (vii) a densidade aparente e básica média do lenho foi significativamente mais elevada (Tectona) e os valores de densidade mínima e máxima média foram mais discrepantes no lenho das árvores de Pinus e (viii) o teor de umidade médio do lenho foi significativamente superior em Tectona, com a maior discrepância dos valores médios mínimo e máximo no lenho das árvores de Pinus. No presente trabalho são discutidas as vantagens da aplicação de MND na análise do tronco das árvores de plantações florestais
The application of non-destructive methods (MND) invasive - extraction of samples from the trunk of trees with metal probes - and not invasive - analysis of the wood directly on the trunk - to evaluate the quality of the wood, the internal defects and their application as solid wood, etc. In the present study are applied MND invasive (X-ray densitometry) and noninvasive (tomography of impulse) in the analysis of the trunk of 18 trees of Pinus caribaea var. hondurensis and 18 of Tectona grandis, with 18 and 52 years, respectively. The results suggest that (i) gross anatomical structure of wood and the growth rings described is characteristic of conifers (Pine) and hardwood (Teak) and similar to that presented in the literature, (ii) tomographyc images of the cross section of wood indicate a good state of health (Pinus) and affected regions of the wood (Tectona), the wave velocity is higher in the inner region compared to external (Pine) and higher in one of the rays, decreasing toward the pith and the opposite ray (Tectona) of wood, and allows the grouping of trees in 4 (Pine) and 6 (Tectona) classes, we observe the correlation of stem diameter with the time average of velocity of wave (iii) the density profiles diametrical and basic density of wood show an increase from pith to bark and the wood external stabilization, the radial density profiles allow a precise demarcation of the annual growth rings, the average density of trees in group 3-2 (Pine) and 6-5 (Tectona) classes no significant correlation with the trunk diameter, (iv) the diametric profiles of moisture content of wood indicate a decrease from pith to bark and the wood external stabilization, allow you to group trees in 3 (Pine) and 5 (Tectona) classes and do not correlate with the diameter of the trunk, (v) the Pearson correlation coefficient showed negative and not significant between the wave velocity and density basic of wood (Pine) and between wave velocity and density of wood (Tectona), positive and not significant for moisture content (Pine) and positive and not significant for moisture content and density (Tectona), negative correlation between moisture content and density wood basic density and (vi) the average speed of wave in the wood is less and greater variation of minimum and maximum velocities in Tectona, in relation to Pine trees, (vii) and average basic density of wood was significantly higher (Tectona) and the values of minimum density and maximum density were more discrepant in the wood of pine trees and (viii) the average moisture content of wood was significantly higher in Tectona, with the largest discrepancy between the minimum and average values maximum in the wood of Pine trees. In this paper we discussed the advantages of applying MND in the analysis of tree trunks in forest plantations.

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Alvarado, Jedi Rosero. "Dendrocronologia de árvores de mogno, Swietenia macrophylla King., Meliaceae, ocorrentes na floresta tropical Amazônica do Departamento de Madre de Dios, Peru". Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-18052009-165913/.

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Estudos sobre a fenologia e anatomia do lenho de árvores de espécies tropicais revelam um desenvolvimento e crescimento cíclicos, relacionados com as condições climáticas (temperatura e precipitação) e de sítio (competição, luz, armazenamento de água no solo, etc.). A sensibilidade a estes fatores resulta, para as árvores de algumas espécies, na sazonalidade da atividade cambial e na formação de anéis de crescimento anuais. Essa característica possibilita a determinação da idade, da taxa de crescimento em diâmetro do tronco e da reconstrução de eventos climáticos, bem como na aplicação de técnicas de manejo florestal sustentável. No presente trabalho, foram aplicadas as técnicas de dendrocronologia, em árvores de mogno, de duas populações na floresta tropical Amazônica do Peru, visando a (i) caracterização da estrutura macro e microscópica do lenho e dos anéis de crescimento, (ii) comprovação da anualidade da formação dos anéis de crescimento e determinação da idade das árvores, (iii) avaliação da biodeterioração do lenho das árvores, (iv) aplicação da densitometria de raios X no estudo do lenho e dos anéis de crescimento e (v) aplicação dos anéis de crescimento em dendroclimatologia e dendroecologia. Foram selecionadas 20 árvores de mogno em duas populações localizadas no Departamento de Madre de Dios, Peru e extraídas amostras radiais do seu lenho, com sonda de Pressler. Injúrias no tronco de árvores de mogno foram realizadas em outubro/2006 e analisadas as cicatrizes no lenho em outubro/2007, relacionando-as com a formação dos anéis de crescimento. Foi caracterizada a estrutura anatômica do lenho e dos anéis de crescimento, determinando-se o seu número, largura e aplicadas técnicas de dendrocronologia. Os anéis de crescimento foram sincronizados, utilizando os programas COFECHA, ARSTAN e RESPO, determinando-se a relação da sua largura com as variáveis climáticas e a idade das árvores. A podridão interna do lenho das árvores foi avaliada determinando-se o diâmetro do oco interno do lenho do tronco. A variação radial da densidade aparente do lenho foi determinada pela densitometria de raios X. Anéis de crescimento delimitados pelo parênquima axial marginal são comprovadamente anuais e possibilitaram a determinação da idade das árvores de mogno (80-122 anos) e a construção de cronologias. A variável climática determinante para o maior crescimento em diâmetro do tronco das árvores foi a precipitação dos meses prévios, do início e do final da estação chuvosa (junho-agosto, dezembro e março) indicando o seu potencial para as reconstruções climáticas. Os perfis radiais de densidade aparente do lenho, obtidos por densitometria de raios X, possibilitaram a identificação do limite exato dos anéis de crescimento, pelos valores mínimos de densidade da região do parênquima marginal. A análise de regressão entre a largura dos anéis obtida pela mesa de medição e por densitometria de raios X apresentou valor de r2=0.92, mostrando a potencialidade dos raios X como ferramenta para estudos de dendrocronologia. O oco do lenho do tronco foi observado em 20% das árvores de mogno, com DAP acima de 62 cm.
Studies in phenology and wood anatomy show a cyclical development and growth related to climatic conditions (temperature and rainfall) and site characteristics (competence, light, water storage in the soil, etc.), the sensibility to these factors results, for some tree species, in seasonality of cambium activity and formation of annual tree-rings. This characteristic enables to estimate age, growth rate in trunk diameter and reconstruction of climatic events, as well as in application of techniques of sustainable forest management. In this study, dendrochronological techniques were applied in mahogany trees from two populations in the Amazon rainforest of Peru, with the aim of (i) characterization of macroscopic and microscopic wood structure and the tree rings, (ii) checking the annual formation of tree rings and determining tree age, (iii) evaluation of the biodeterioration in wood of trees (hollow), (iv) application the X-ray densitometry in the study of wood and tree rings and (v) application the tree rings in dendroclimatology and dendroecology. Twenty mahogany trees were selected in two populations located in the department of Madre de Dios, Peru and removed radial samples from the trunk, with increment corer (Pressler). In October, 2006 injuries in the trunk of mahogany trees were carried out and in October 2007, the scars were analyzed, associating them to the formation of the tree rings. Wood and tree rings anatomic structure was characterized determining its number, width and dendrochronology techniques applied. Tree rings have been synchronized, using COFECHA, ARSTAN and RESPO programs, determining the relation between the width with the climatic variables and the age of trees. The internal wood decay was evaluated by providing the internal diameter of hollow in the trunk. The radial variation of the apparent wood density was determined by the X ray densitometry. Tree rings delimited by a marginal axial parenchyma bands are annual and enable to determine the age of mahogany trees (80-122 years) and the construction of chronologies. The climatic determinant variable for the greatest growth in diameter of the trunk of trees was the rainfall in the previous months, beginning and final of the rainy season (June - August, December and March) indicating its potential for climatic reconstructions. The radials profiles of apparent density of wood, obtained for X ray densitometry, making possible identification of the exact limit of growth rings for minimal values of density in the region of marginal parenchyma. The regression analysis between ring width measured with Velmex (0,001) table and for X ray was r2=0.92, showing the potential of X rays as tool for dendrochronological studies. Decay in the trunk was observed in 20 % of trees over 62 cm of DBH.

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Pokhrel, Damodar. "Brachytherapy Seed and Applicator Localization via Iterative Forward Projection Matching Algorithm using Digital X-ray Projections". VCU Scholars Compass, 2010. http://scholarscompass.vcu.edu/etd/2283.

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Interstitial and intracavitary brachytherapy plays an essential role in management of several malignancies. However, the achievable accuracy of brachytherapy treatment for prostate and cervical cancer is limited due to the lack of intraoperative planning and adaptive replanning. A major problem in implementing TRUS-based intraoperative planning is an inability of TRUS to accurately localize individual seed poses (positions and orientations) relative to the prostate volume during or after the implantation. For the locally advanced cervical cancer patient, manual drawing of the source positions on orthogonal films can not localize the full 3D intracavitary brachytherapy (ICB) applicator geometry. A new iterative forward projection matching (IFPM) algorithm can explicitly localize each individual seed/applicator by iteratively matching computed projections of the post-implant patient with the measured projections. This thesis describes adaptation and implementation of a novel IFPM algorithm that addresses hitherto unsolved problems in localization of brachytherapy seeds and applicators. The prototype implementation of 3-parameter point-seed IFPM algorithm was experimentally validated using a set of a few cone-beam CT (CBCT) projections of both the phantom and post-implant patient’s datasets. Geometric uncertainty due to gantry angle inaccuracy was incorporated. After this, IFPM algorithm was extended to 5-parameter elongated line-seed model which automatically reconstructs individual seed orientation as well as position. The accuracy of this algorithm was tested using both the synthetic-measured projections of clinically-realistic Model-6711 125I seed arrangements and measured projections of an in-house precision-machined prostate implant phantom that allows the orientations and locations of up to 100 seeds to be set to known values. The seed reconstruction error for simulation was less than 0.6 mm/3o. For the physical phantom experiments, IFPM absolute accuracy for position, polar angle, and azimuthal angel were (0.78 ± 0.57) mm, (5.8 ± 4.8)o, and (6.8 ± 4.0)o, respectively. It avoids the need to match corresponding seeds in each projection and accommodates incomplete data, overlapping seed clusters, and highly-migrated seeds. IFPM was further generalized from 5-parameter to 6-parameter model which was needed to reconstruct 3D pose of arbitrary-shape applicators. The voxelized 3D model of the applicator was obtained from external complex combinatorial geometric modeling. It is then integrated into the forward projection matching method for computing the 2D projections of the 3D ICB applicators, iteratively. The applicator reconstruction error for simulation was about 0.5 mm/2o. The residual 2D registration error (positional difference) between computed and actual measured applicator images was less than 1 mm for the intrauterine tandem and about 1.5 mm for the bilateral colpostats in each detector plane. By localizing the applicator’s internal structure and the sources, the effect of intra and inter-applicator attenuation can be included in the resultant dose distribution and CBCT metal streaking artifact mitigation. The localization accuracy of better than 1 mm and 6o has the potential to support more accurate Monte Carlo-based or 2D TG-43 dose calculations in clinical practice. It is hoped the clinical implementation of IFPM approach to localize elongated line-seed/applicator for intraoperative brachytherapy planning may have a positive impact on the treatment of prostate and cervical cancers.

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Leal, Michael J. "Effect of pixel size and scintillator on image quality of a CCD-based digital x-ray imaging system". Link to electronic thesis, 2001. http://www.wpi.edu/Pubs/ETD/Available/etd-0502101-123456.

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Halliwell, Lauren. "Investigation and synthesis of alkyl cyanoacrylates and modification of X-ray contrast agents for incorporation into alkyl cyanoacrylate for use in medical devices". Thesis, University of Warwick, 2013. http://wrap.warwick.ac.uk/57640/.

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The work in this thesis involves the development of a protected transesterification route for the production of novel cyanoacrylate monomers. As well as the modification of iodinated contrast agents to increase their solubility in cyanoacrylate, to enable monitoring of the adhesive within the body for possible use in the treatment of brain aneurysms. Chapter 1 provides an introduction to biological adhesives, in particular alky 2-cyanoacrylates and how they degrade to release formaldehyde. Details into iodinated X-ray contrast agents, their structure, uses and synthesis, as well as the current treatments for brain aneurysms. Chapter 2 focuses on the modification of several iodinated contrast agents in order to increase solubility in ethyl cyanoacrylate. Three existing contrast agents were protected using a variety of different protecting groups and tested for solubility in ethyl cyanoacrylate. Partition coefficients were calculated for the successfully modified compounds. Chapter 3 outlines the development of the anthracene protected route for the synthesis of cyanoacrylate monomers, utilising the Diels- Alder and retro-Diels-Alder reactions of anthracene. This route was subsequently used to synthesis a range of cyanoacrylate monomers. Polymerisation of these monomers gave a range of polymers which were tested to determine their rate of degradation through formaldehyde detection. Chapter 4 further details the first and final step of the anthracene protected route developed in chapter 3. It involved 1H NMR experiments to determine how substitution at the 9 and 10 position of anthracene affects the rate of reaction of the forward and retro-Diels-Alder reaction.

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Jorgenson, Todd F. "Comparison of two imaging modalities : F-speed film and digital images for detection of osseous defects in patients with vertical bone defects /". Oklahoma City : [s.n.], 2003.

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Portal, Cahuana Leif Armando. "Potencial dendrocronol?gico de ?rvores da fam?lia Fabaceae Na Floresta Tropical Amaz?nica Do Peru". Universidade Federal Rural do Rio de Janeiro, 2017. https://tede.ufrrj.br/jspui/handle/jspui/2060.

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Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES
The objective of this work was to determine the dendrochronological potential of five forest species of the Fabaceae family from Amazonia Peru. Five native tree species (Apuleia leiocarpa, Hymenaea oblonglifolia, Myroxylon balsamum, Amburana cearensis and Dipteryx odorata), which occur naturally in the Madre de Dios region of Peru, were used. The anatomical characteristics of the wood, growth ring characterization, dendrochronology, growth modeling and X-ray microdensitometry were determined. In the study of the anatomy and characterization of growth rings, the species H. oblonglifolia and A. cearensis presented rings of Growth to the naked eye, demarcated by the fibrous zones and the marginal parenchyma. In the study of dendrochronology the master chronological series of the H. oblonglifolia species of 1778-2013 years and A. cearensis of 1866-2013 years were constructed, and the relation with the climate of the region (precipitation and temperature), it was verified that the variable Climatic conditions in the area of study determining for the greatest growth in diameter of the trunks of the trees was the last rainfall the species presented answers common to the El Ni?o phenomenon. In the growth modeling study, the species A. cearensis was determined the minimum age according to the Law of Peru of 96 years and a technical age of 58 years and for H. oblonglifolia, it was determined the minimum age according to Law Of Peru of 123 years and a technical age of 57 years. Finally, in the study of the radial physical and anatomical variability of the tree wood of Amburana cearensis, X-ray microdensitometry provided an accurate measurement of the variations in the apparent density of A. cearensis wood, indicative of its anatomical structure and demarcating the limits of the rings Fibrous areas.
O objetivo do trabalho foi Este trabalho foi determinar o potencial dendrocronol?gico de cinco esp?cies florestais da fam?lia Fabaceae oriunda da Amaz?nia Peru. Foram utilizadas cinco esp?cies arb?reas nativas (Apuleia leiocarpa, Hymenaea oblonglifolia, Myroxylon balsamum, Amburana cearensis e Dipteryx odorata), de ocorr?ncia natural na regi?o de Madre de Dios no Peru. Foram determinadas as caracter?sticas anat?micas do lenho, caracteriza??o dos an?is de crescimento, dendrocronologia, modelagem de crescimento e a microdensitometria de raios X. No estudo da anatomia e caracteriza??o dos an?is de crescimento, as esp?cies H. oblonglifolia e A. cearensis, apresentaram an?is de crescimento ao olho nu, demarcados pelas zonas fibrosas e o par?nquima marginal. No estudo de dendrocronologia foram constru?das as s?ries cronol?gicas mestre das esp?cies H. oblonglifolia de 1778-2013 anos e A. cearensis de 1866-2013 anos, e a rela??o com o clima da regi?o (precipita??o e temperatura), verificou-se que a vari?vel clim?tica na ?rea de estudo determinante para o maior crescimento em di?metro dos troncos das ?rvores foi a precipita??o por ?ltimo as esp?cies apresentaram respostas comuns ao fen?meno do El Ni?o. No estudo de modelagem de crescimento a esp?cie A. cearensis, determinou-se a idade m?nima em fun??o a Lei do Peru de 96 anos e uma idade t?cnica de 58 anos e para H. oblonglifolia, determinou-se a idade m?nima em fun??o a Lei do Peru de 123 anos e uma idade t?cnica de 57 anos. Por ?ltimo no estudo da variabilidade radial f?sica e anat?mica do lenho de ?rvores de Amburana cearensis, a microdensitometria de raios X proporcionou uma mensura??o acurada das varia??es da densidade aparente do lenho de A. cearensis, indicativas da sua estrutura anat?mica e demarcando os limites dos an?is pelas zonas fibrosas

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Dianessa, Danielli. "Densidade da madeira e potencial dendrocronológico de espécies nativas da floresta ombrófila mista". Universidade do Estado de Santa Catarina, 2017. http://tede.udesc.br/handle/handle/2349.

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The present work had as objectives: the determination of the apparent density of the wood by the method of X-ray densitometry and the stereometric method of 19 species; show the dendrochronological potential, determine the age and growth rate of the trunk of the trees by the annual growth rings of seven species with natural occurrence in the Mixed Ombrophylous Forest of Planalto Catarinense. The material was collected in a destructive way, with three trees of each species being selected, each one being discarded at the level of the chest, with a thickness of approximately 5 cm each disc. To determine the apparent density, samples of 2 mm thickness were removed from each disk, which were conditioned in an air conditioning chamber until the equilibrium moisture content was 12%. They were then transferred to the irradiation chamber of the X-ray equipment and exposed to scanning in a collimated X-ray beam, and the wood density evaluation was performed by X-ray densitometry. To determine the density by the stereometric method, according to norm NBR 7190, 6 specimens of each disc were made in the medulla-intermediate-bark direction. Thus, it was possible to establish the average values of the apparent density for each species and to compare the two determination methods used. In order to obtain Dendrochronology data, the surfaces of the three disks of each species were polished with sandpaper of different particle sizes and the growth rings were characterized macroscopically using a portable digital microscope (DinoLite). For dendrochronological analysis, the samples were digitized and the width of the growth rings was measured using the Image Pro Plus image analysis software, and the data were exported to Microsoft Office Excel. rings of growth. The cross-dating of the trees was then performed, allowing the construction of a chronological series of growth rings and the test of the quality of the synchronization of the growth between the samples of each species, using the software COFECHA, obtaining the average series. With the results of the apparent density of the wood, it is possible to conclude that the densitometric profiles help to observe the rings of growth in the wood of the trees, these are distinguishable in the species that presented the smaller apparent densities. The mean values of apparent density for the studied species were presented. Of the 19 species, 10 were classified as high density, five medium density and four low apparent density. The results obtained through the use of the two methods of determination of the density were similar when observed the average values and the high correlation obtained. As for dendrochronology, it was possible to construct the chronologies and establish the age of the trees and also to perform the macroscopic characterization of the growth rings, and the observed characters confirm the already made descriptions of the species or genera. The species Allophylus edulis, Eugenia pyriformis, Ocotea indecora, Ocotea puberula, Vernonanthura discolor, present a significant correlation of the chronological series, whereas the species Piptocarpha angustifolia and Styrax leprosus did not obtain a significant correlation. In relation to the Annual Average Radial Increase (IRMA), the species Ocotea puberula and Vernonanthura discolor presented the highest values and the lowest IRMA were for the species Allophylus edulis and Piptocarpha angustifolia
O presente trabalho teve como objetivos: a determinação da densidade aparente da madeira pelo método de densitometria de raios X e pelo método estereométrico de 19 espécies; mostrar o potencial dendrocronológico, determinar a idade e taxa de crescimento do tronco das árvores pelos anéis de crescimento anuais de sete espécies com ocorrência natural na Floresta Ombrófila Mista do Planalto Catarinense. A coleta do material foi feita de forma destrutiva, sendo selecionadas três árvores de cada espécie, retirado um disco de cada à altura do peito, com espessura de aproximadamente 5,0 cm cada disco. Para determinação da densidade aparente foram retiradas amostras de 2,0 mm de espessura de cada disco, que foram acondicionadas em câmara de climatização até o teor de umidade de equilíbrio de 12%. Em seguida, foram transferidas para a câmara de irradiação do equipamento de raios X e expostas à varredura em um feixe colimado de raios X, sendo realizada a avaliação da densidade do lenho por densitometria de raios X. Para determinação da densidade pelo método estereométrico, atendendo a norma NBR 7190, foram confeccionados 6 corpos-de-prova de cada disco no sentido medula-intermediário-casca. Assim, foi possível estabelecer os valores médios da densidade aparente para cada espécie e ainda comparar os dois métodos de determinação utilizados. Para obtenção dos dados de Dendrocronologia, as superfícies dos três discos de cada espécie foram polidas com lixas de diferentes granulometrias e os anéis de crescimento foram caracterizados macroscopicamente utilizando um microscópio digital portátil (DinoLite). Para análise dendrocronologica, as amostras foram digitalizadas e feita a mensuração da largura dos anéis de crescimento através do software de análise de imagens Image Pro Plus, sendo os dados exportados para o Microsoft Office Excel, sendo feitas as primeiras avaliações das séries de medidas radiais dos anéis de crescimento. Em seguida foi feita a datação-cruzada das árvores, possibilitando a construção de uma série cronológica de anéis de crescimento e o teste da qualidade da sincronização do crescimento entre as amostras de cada espécie, utilizando o software COFECHA, obtendo-se a série média. Com os resultados da densidade aparente da madeira, é possível concluir que os perfis densitométricos ajudam a observar os anéis de crescimento no lenho das árvores, estes são distinguíveis nas espécies que apresentaram as menores densidades aparentes. Apresentar os valores médios de densidade aparente para as espécie estudadas, sendo que das 19 espécies, 10 foram classificadas como de alta densidade, cinco de média densidade e quatro de baixa densidade aparente. Os resultados obtidos através do uso dos dois métodos de determinação da densidade aprente foram semelhantes quando observados os valores médios e a alta correlação obtida. Quanto a dendrocronologia, foi possível fazer a construção das cronologias e estabelecer a idade das árvores e também realizar a caracterização macroscópica dos anéis de crescimento, sendo que os caracteres observados confirmam as descrições já feitas das espécies ou gêneros. As espécies Allophylus edulis, Eugenia pyriformis, Ocotea indecora, Ocotea puberula, Vernonanthura discolor, apresentam correlação significativa da série cronológica, já as espécies Piptocarpha angustifolia e Styrax leprosus não obtiveram correlação significativa. Em relação ao Incremento Radial Médio Anual (IRMA), as espécies Ocotea puberula e Vernonanthura discolor apresentaram os maiores valores e os menores IRMA foram para as espécies Allophylus edulis e Piptocarpha angustifolia

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Abubakar, Sofiullah. "The conclusions drawn from ventilation/perfusion single photon emission computed tomography (SPECT) compared to lung perfusion SPECT and a chest x-ray (CXR) in patients with suspected pulmonary pulmonary thromboembolism". Master's thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/29578.

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Purpose: There are conflicting results from studies on whether the ventilation (V) scintigraphy can be safely omitted or replaced by a chest x-ray. These studies were based on planar ventilation perfusion (V/Q) scintigraphy. We evaluated the value of the V single photon emission computed tomography (SPECT) on the final conclusion drawn from a V/Q SPECT and the possible role of the chest x-ray as a surrogate for the V SPECT. Methods Raw data of V/Q SPECT images and chest x-ray acquired within 48 hours over 18 months period were retrieved, reprocessed and reviewed in batches. The V SPECT, Q SPECT and chest x-ray were reviewed separately and in combination. Data on the presence and character of defects and chest x-ray abnormalities were recorded. The V/Q SPECT images were interpreted using the criteria in the EANM guideline and the Q SPECT and chest x-ray images were interpreted using the PISAPED criteria. Agreement between the diagnosis on the V/Q SPECT review and the Q SPECT and chest x-ray review was analysed. Results 21.1% of the patients were classified as 'PE present’ on the V/Q SPECT review whereas 48.9% were classified as 'PE present’ on the Q SPECT and chest x-ray review. Only 5.4% of defects seen on V SPECT had matched chest x-ray lung field opacity. Conclusion Our study showed that the omission of a V SPECT led to a high rate of false positive diagnoses and that the ventilation scan cannot be replaced by a chest x-ray.

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Ferreira, Angel Thiane Boschiero. "Caracterização da estrutura anatômica do lenho, dos anéis de crescimento e dos canais de resina de árvores de Pinus caribaea var. hondurensis Barr. et Golf". Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-18052009-151531/.

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As pesquisas com resinagem de árvores de espécies de pinus têm mostrado o efeito de fatores que afetam a produção e a qualidade da resina, relacionado com as espécies, variabilidade genética, taxa de crescimento, idade, manejo florestal, etc. As práticas de extração da goma-resina, a concentração, freqüência da aplicação de estimulantes químicos, época de abertura dos painéis, etc., têm sido, da mesma forma, analisadas. No entanto, há necessidade do desenvolvimento de pesquisas direcionadas ao estudo da formação e da estrutura do lenho e dos canais de resina das árvores de pinus. Pelo exposto, o presente trabalho teve como objetivos a caracterização da estrutura anatômica do lenho, dos anéis de crescimento e dos canais de resina, através de metodologias de histologia e de densitometria de raios X, de amostras de árvores de Pinus caribaea var. hondurensis resinadas e não resinadas, de três classes de diâmetro. Árvores de pinus, de plantação florestal instalada em 1969, na Estação Ecológica Experimental de Itirapina, do Instituto Florestal do Estado de São Paulo, foram mensuradas e estratificadas em três classes de diâmetro do tronco. As árvores de pinus têm sido resinadas desde 2004, com a abertura de dois painéis simultâneos e opostos. Sessenta amostras do lenho das árvores de pinus foram extraídas do tronco das árvores através de método não destrutivo e, em laboratório, (i) analisada e descrita a estrutura anatômica macro e microscópica do lenho; (ii) caracterizados os anéis de crescimento e determinada a densidade aparente do lenho por densitometria de raios X; (iii) caracterizados e descritos os canais de resina axiais e radiais e sua interconexão. Os resultados das análises evidenciaram que (i) a estrutura anatômica macro e microscópica do lenho e dos anéis de crescimento é característica da espécie; (ii) os anéis de crescimento falsos ocorrem nos lenhos inicial e tardio dos anéis de crescimento anuais devido as variações climáticas; (iii) a análise dos anéis de crescimento demonstrou que as árvores têm 38 anos, comprovada pela data de plantio; (iv) o comprimento e a espessura da parede das traqueídes não diferiram nas três classes de diâmetro do tronco; (v) a largura e o diâmetro do lume das traqueídes mostraram diferenças significativas, com maiores valores na classe de maior diâmetro do tronco; (vi) a densitometria de raios X possibilitou a demarcação dos limites dos anéis de crescimento e a determinação da freqüência dos canais de resina axiais; (vii) a densidade aparente média do lenho mostrou diferença significativa entre as árvores da classe de diâmetro alta em relação as das classes média-baixa; (viii) os canais de resina axiais localizam-se em maior freqüência no lenho tardio e apresentaram maior diâmetro de menor classe de diâmetro; (ix) as características do lenho e dos canais de resina nas faces testemunha e resinada não mostraram diferenças significativas.
The research on resin tapping trees with pine species have shown the effect of factors that affect the production and quality of resin, related with the species, genetic variability, growth rate, age, forest management, etc.. The gum-resin extraction practices, the concentration, frequency of application of chemical stimulants, the time of year that panels are opening, etc., have been in the same manner, discussed. However, there is need for further research directed to study the formation and structure of the wood and resin canals from the pine trees. Therefore, this work aimed to characterize the anatomical structure of wood, the tree rings and resin canals, through methodology of histology and X-ray densitometry, of resin tapped and not resin tapped Pinus caribaea var. hondurensis trees samples, of three diameter classes. Pine trees, in forest plantation established in 1969, in the Ecological Experimental Station of Itirapina, from the Forestry Institute of São Paulo State, were measured and stratified into three classes of diameter of the trunk. The pine trees have been resin tapped since 2004, with the opening of two simultaneous and opposing panels. Sixty samples of pine wood trees were extracted from the tree trunk through a non-destructive method, and in the laboratory, (i) examined and described the macro- and microscopic anatomical structure of wood, (ii) characterized the tree rings and determined the wood apparent density by X-ray densitometry, (iii) characterized and described the ducts for axial and radial resin and its inter-connection. The test results showed that (i) the macro- and microscopic anatomical structure of wood and the tree rings are characteristic of the species, (ii) the false tree rings occur in the early wood and latewood of the tree rings due to climate change (iii) the analysis of tree rings showed that 38 years have proven the date of planting of the trees, (iv) the length and thickness of tracheids wall did not differ in the three diameter classes of the trunk, (v) the tracheids lumen width and diameter showed significant differences, with higher values in the larger diameter class trunk, (vi) the Xray densitometry allowed the demarcation of the tree rings limits and determination of the axial resin canals frequency (vii) the wood apparent density average was significantly different between the trees in high class diameter from the medium-low, (viii) the axial resin canals can be found more frequently in the latewood and had larger diameter in the lowest diameter class, (ix) the wood and resin canals characteristics from the resin tapped and no resin tapped faces did not show significant differences.

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Benjamin, Cláudia Assumpção [UNESP]. "Estudo da estrutura anatômica e das propriedades físicas e mecânicas da madeira de Corymbia (Eucalyptus) citriodora e Eucalyptus grandis". Universidade Estadual Paulista (UNESP), 2006. http://hdl.handle.net/11449/101780.

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Universidade Estadual Paulista (UNESP)
Este trabalho teve por objetivo estudar as correlações existentes entre as propriedades físicas e mecânicas da madeira de eucalipto proveniente de árvores com presença de madeira juvenil e adulta. O estudo foi conduzido com a caracterização complementar da estrutura anatômica da madeira sob análise, a partir de análises microscópicas do lenho. Estudaram-se 12 árvores, sendo seis de E. grandis com 28 anos de idade e seis de Corymbia (Eucalyptus) citriodora com 29 anos de idade. As árvores foram disponibilizadas pela Estação Experimental de Ciências Florestais (EECF - LCF/ESALQUSP), localizada no município de Anhembi-SP. A partir do DAP, no sentido da base da árvore, foi retirada uma tora de 70 cm de comprimento. Da tora, foram retirados um disco para determinação da densidade básica da madeira da árvore e uma prancha central, para obtenção dos corpos-de-prova utilizados para os ensaios de propriedades físico-mecânicas e análises anatômicas da madeira. Nas 12 árvores amostradas foram mensuradas (ao longo do sentido medula-casca, lados direito e esquerdo) a densidade aparente da madeira, utilizando-se da técnica da densitometria de raios X e a densidade básica por mensuração e pesagem de corpos-de-prova. Ainda nesse sentido, em intervalos aproximadamente regulares de 35 mm, foram mensuradas as retratibilidades lineares e volumétricas. As resistências à compressão e à dureza paralela às fibras também foram medidas com a mesma regularidade ao longo do raio, com a madeira verde (na umidade de abate da árvore) e na umidade de equilíbrio ao ar ao longo de todo o raio. Para seis das 12 árvores (três árvores por espécie) foram mensuradas, 2 em três posições distintas na direção radial, algumas importantes características anatômicas do lenho, em regiões coincidentes com aquelas...
This paper had the objective of studying the correlation between physical and mechanical properties of Eucalyptus wood from trees with expressive presence of both juvenile and mature wood. The study was carried out with complementary characterization of the anatomical structure of wood, using microscopic analyses. It were sampled 12 trees, six from Eucalytpus grandis 28 years old and six from Corymbia (Eucalyptus) citriodora 29 years old. Trees were obtained from Forestal Science Experimental Station of ESALQ-USP - Escola Superior de Agricultura Luiz de Queiróz at Anhembi-São Paulo State - Brazil. From DBH to the base of each tree it was sawed a log, 70cm long, from which it was cut a disc, 7 cm thick, for specific gravity determination and, in the remaining log was cut a central board (approximately 63cm long) to produce specimens for physical and mechanical properties determination. On all the trees (from pith to bark, right and left sides) it were evaluated the radial variation of specific gravity and density (12% MC) using X-ray densitometry and conventional methods. On regular intervals of 35mm from pith to bark, using specimens, it were measured radial, tangential, longitudinal and volumetric shrinkage and compression and hardness parallel to grain strength (green wood and wood at EMC for mechanical tests). For three of the 12 trees, in three different position along one of the radius of the tree, it were also measured several anatomical characteristics, on region coincident with those of the specimens for physical and mechanical tests. With the obtained results it were established patterns of variation of all measured properties on radial direction, taking in account the effects of specie, side (right and 4 left) and important features of xylem (heart wood/sapwood and juvenile wood/mature wood). It were... (Complete abstract, click electronic access below)

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Oliveira, Ivanka Rosada de. "Avaliação do crescimento e da qualidade do lenho de árvores de Cariniana legalis (Martius) O. Kuntze submetidas a diferentes espaçamentos". Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-08042015-144912/.

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O presente estudo tem por objetivo avaliar o crescimento e a qualidade do lenho das árvores de Cariniana legalis submetidas a diferentes espaçamentos (3x1,5; 3x2; 3x2,5 m). O experimento localiza-se na Estação Experimental de Luiz Antônio-SP, do Instituto Florestal do Estado de São Paulo. Foram selecionadas 30 árvores de jequitibá rosa (10 árvores/tratamento) e seccionados discos na base, DAP e a cada 5m do tronco até a altura comercial das árvores. Foram realizadas as análises (i) anatômicas, com a descrição macro e microscópica do lenho com ênfase aos anéis de crescimento e (ii) dendrocronológicas, para a comprovação da anuidade da formação dos anéis de crescimento; (iii) densitometria de raios X, para obtenção do perfil longitudinal - radial de densidade aparente do lenho e imagem digital do lenho; (iv) dendroclimatologia, para verificar a influência dos fatores climáticos, como a precipitação e temperatura na formação dos anéis de crescimento e da (v) influência do espaçamento no crescimento radial acumulado/médio anual do tronco e no volume das árvores/ha. Os resultados indicaram que as árvores de C. legalis apresentam anéis de crescimento distintos, com a dendrocronologia confirmando a idade das árvores (38 anos) e a anuidade da formação dos anéis de crescimento. A densidade aparente do lenho decresce da base até a região intermediária, tendendo a aumentar próximo ao topo do tronco das árvores, com o maior valor no maior e menor espaçamento. As imagens digitais do lenho indicaram um decréscimo da densidade aparente do lenho no sentido medula - casca. Nos três espaçamentos, a análise dendroclimatológica indicou uma influência significativa das variáveis climáticas no crescimento radial do tronco das árvores de Cariniana legalis. Os meses do ano que influenciaram o crescimento radial do tronco das árvores foram distintos entre os tratamentos sendo que, entretanto, verifica-se um padrão de crescimento do tronco semelhante e relacionado com a precipitação mensal acumulada. O espaçamento entre árvores influenciou diretamente no ritmo de crescimento do tronco das árvores, sendo que as do maior espaçamento apresentaram a maior produção volumétrica do lenho, e as do menor espaçamento, o maior volume de madeira/ha. Conclui-se que a área do espaço vital (espaçamento) influencia significativamente o desenvolvimento das árvores de Cariniana legalis.
The present study aims to assess growth and wood quality of Cariniana legalis trees in forest plantations under different espacements (1.5x3, 3x2, 3x2.5 m). The experiment is located in Luiz Antônio, São Paulo, at the Experimental Station belonging to the Forest Institute of São Paulo. It was selected 30 trees of \"jequitibá rosa\" (10 per treatment) and sectioned discs were removed at the base, DBH and every 5m to commercial height. With these samples 5 different analyzis were performed: (i) anatomical, by means of wood macroscopic and microscopic description with a view to growth rings, (ii) dendrochronological, to prove growth rings annuality; (iii) X-ray densitometry and digital X-rays to obtain the radial density profile in the longitudinal and radial direction; (iv) dendroclimatological, for checking the influence of climatic factors (monthly precipitation and average annual temperature) in growth rings formation and (v) verification of espacement influence on cumulative and annual radial growth, volume per tree and per hectare. Wood description indicates C. legalis trees have distinct growth rings. Dendrochronology confirmed annuity formation of growth rings as the number of rings found matches with the age of plantation, 38 years old. Apparent density decreases from the base to the middle region of the stem and tends to increase near the top, with higher average values in both widest and closest espacements. The analysis of digital images indicated a decrease in apparent density in pith-bark direction. Dendroclimatology indicated there was significant influence of climatic variables on radial growth of Cariniana legalis trees. The months influencing radial growth were different between treatments, however there is a similar pattern of growth related to monthly precipitation. The espacements used influenced directly the growth rate of the trees. The ones inserted in widest espacements had the highest volumetric production, on the other hand the largest volume per hectare occurred in the closest espacements. The conclusion was that size of living space influences significantly the development of C. legalis trees.

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COSTA, ALESSANDRO M. da. "Desenvolvimento de camaras de ionizacao Tandem para utilizacao em programas de controle da qualidade em radioterapia e radiodiagnostico". reponame:Repositório Institucional do IPEN, 2003. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11103.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
FAPESP:98/14763-4

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Benjamin, Cláudia Assumpção 1965. "Estudo da estrutura anatômica e das propriedades físicas e mecânicas da madeira de Corymbia (Eucalyptus) citriodora e Eucalyptus grandis /". Botucatu : [s.n.], 2006. http://hdl.handle.net/11449/101780.

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Orientador: Adriano Wagner Ballarin
Banca: Hernando Alfonso Lara Palma
Banca: Carlos Roberto Padovani
Banca: Mário Tomazello Filho
Banca: Takashi Yojo
Resumo: Este trabalho teve por objetivo estudar as correlações existentes entre as propriedades físicas e mecânicas da madeira de eucalipto proveniente de árvores com presença de madeira juvenil e adulta. O estudo foi conduzido com a caracterização complementar da estrutura anatômica da madeira sob análise, a partir de análises microscópicas do lenho. Estudaram-se 12 árvores, sendo seis de E. grandis com 28 anos de idade e seis de Corymbia (Eucalyptus) citriodora com 29 anos de idade. As árvores foram disponibilizadas pela Estação Experimental de Ciências Florestais (EECF - LCF/ESALQUSP), localizada no município de Anhembi-SP. A partir do DAP, no sentido da base da árvore, foi retirada uma tora de 70 cm de comprimento. Da tora, foram retirados um disco para determinação da densidade básica da madeira da árvore e uma prancha central, para obtenção dos corpos-de-prova utilizados para os ensaios de propriedades físico-mecânicas e análises anatômicas da madeira. Nas 12 árvores amostradas foram mensuradas (ao longo do sentido medula-casca, lados direito e esquerdo) a densidade aparente da madeira, utilizando-se da técnica da densitometria de raios X e a densidade básica por mensuração e pesagem de corpos-de-prova. Ainda nesse sentido, em intervalos aproximadamente regulares de 35 mm, foram mensuradas as retratibilidades lineares e volumétricas. As resistências à compressão e à dureza paralela às fibras também foram medidas com a mesma regularidade ao longo do raio, com a madeira verde (na umidade de abate da árvore) e na umidade de equilíbrio ao ar ao longo de todo o raio. Para seis das 12 árvores (três árvores por espécie) foram mensuradas, 2 em três posições distintas na direção radial, algumas importantes características anatômicas do lenho, em regiões coincidentes com aquelas... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: This paper had the objective of studying the correlation between physical and mechanical properties of Eucalyptus wood from trees with expressive presence of both juvenile and mature wood. The study was carried out with complementary characterization of the anatomical structure of wood, using microscopic analyses. It were sampled 12 trees, six from Eucalytpus grandis 28 years old and six from Corymbia (Eucalyptus) citriodora 29 years old. Trees were obtained from Forestal Science Experimental Station of ESALQ-USP - Escola Superior de Agricultura Luiz de Queiróz at Anhembi-São Paulo State - Brazil. From DBH to the base of each tree it was sawed a log, 70cm long, from which it was cut a disc, 7 cm thick, for specific gravity determination and, in the remaining log was cut a central board (approximately 63cm long) to produce specimens for physical and mechanical properties determination. On all the trees (from pith to bark, right and left sides) it were evaluated the radial variation of specific gravity and density (12% MC) using X-ray densitometry and conventional methods. On regular intervals of 35mm from pith to bark, using specimens, it were measured radial, tangential, longitudinal and volumetric shrinkage and compression and hardness parallel to grain strength (green wood and wood at EMC for mechanical tests). For three of the 12 trees, in three different position along one of the radius of the tree, it were also measured several anatomical characteristics, on region coincident with those of the specimens for physical and mechanical tests. With the obtained results it were established patterns of variation of all measured properties on radial direction, taking in account the effects of specie, side (right and 4 left) and important features of xylem (heart wood/sapwood and juvenile wood/mature wood). It were... (Complete abstract, click electronic access below)
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Munhoz, Juliana Soares Biruel. "Caracterização da produtividade florestal e dos padrões de crescimento de Pinus taeda L. no sul do Brasil através de análise de tronco". Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-28042011-162045/.

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Visando caracterizar a dinâmica de crescimento do Pinus taeda no sul do Brasil, este estudo teve os seguintes objetivos: i) determinar os principais fatores edafo-climáticos e do povoamento associados à ampla variação de produtividade da espécie; e ii) caracterizar padrões de crescimento e uniformidade, do plantio até 9 anos em diferentes regiões edafoclimáticas. Para isso, foram selecionadas 24 parcelas sem desbaste (700m²), com aproximadamente 1450 árvores ha-1, entre 8 a 10 anos de idade, do projeto PPPIB (Produtividade Potencial do Pinus no Brasil), as quais estão localizadas em Jaguariaíva-PR, Ponta Grossa-PR, Rio Negrinho-SC e Três Barras-SC. O clima destas regiões é temperado úmido, com precipitação média anual de 1477mm, com temperaturas máxima, média e mínima de 24,3ºC, 17,9ºC e 12,7ºC. Todas as variáveis biométricas foram determinadas através do banco de dados de inventário (2006-2009), dados de cubagem, análise de tronco (discos), de anéis de crescimento (baguetas) e massa específica aparente (densitometria de raios-X). Coletaram-se solos (0-20cm) nas parcelas de inventário, e obtiveram-se os dados climáticos de estações meteorológicas locais. Através das análises de disco determinaram-se os índices de sítio (idade base 10 anos), e através da bagueta e densitometria de raios-X, estimaramse o padrão de crescimento de todas as parcelas em volume (m³ha-1) e matéria seca (Mgha-1) e seus Incrementos Médios Anuais e Correntes Anuais até o 9º ano. A uniformidade foi avaliada através do coeficiente de variação de volume das árvores dentro das parcelas (CVV) e da percentagem de biomassa em 50% das árvores mais finas (PB50), dos 2 aos 9 anos. As regiões apresentaram grande variação das propriedades físico-químicas do solo, como profundidade (30-140cm), teor de matéria orgânica (23 a 65g dm-3), teor de argila (20 a 85%), quantidade de N (500 a 5300kg ha- 1), e quantidade de P (9 a 84kg ha-1). Aos 9 anos de idade todas parcelas não haviam culminado seu crescimento, e o incremento médio anual com casca (IMAc9), o estoque de biomassa do lenho e índice de sítio de idade base 10 (IS10) variaram de 15 a 35m³ ha-1 ano-1, de 55 a 130Mg ha-1, e 12 a 19m, respectivamente, com maiores valores em Três Barras. Esta caracterização não era possível de ser detectada antes do 6º ano, mostrando que as decisões silviculturais ou genéticas precoces em Pinus precisam ser cuidadosamente consideradas. A produtividade (IMA) foi positivamente relacionada com o IS10, e ambos estiveram relacionados com os maiores teores de matéria orgânica do solo, quantidade de nitrogênio disponível e menores médias de temperatura mínima e déficit hídrico. As florestas mais produtivas se mostraram também mais uniformes (menores CVV e maiores PB50), mas confundidas com material genético superior. Assim, o estudo corrobora o papel dos nutrientes, solos de boa drenagem, e condição climática amena e com baixo déficit hídrico na explicação da elevada produtividade do P.taeda no sul do Brasil, comparativamente a sua região de origem. Baseado nestes resultados, estudos de fertilização, material genético e uso rotineiro de análise do tronco, associado à densitometria de raios-X, podem ser recomendados para o P. taeda.
The study was designed to characterize the growth dynamics of Pinus taeda in south of Brazil and had the following objectives: i) determine the main edaphic, climatic and stand factors associated with the range in productivity of the species; and ii) characterize the growth patterns and uniformity, from planting until 9 years-old, across different edaphic and climatic regions. A total of 24 unthinned plots were selected (700m2), with stocking of 1450 trees ha-1, between 8 and 10 years old, from the PPPIB project (Pine Potential Productivity in Brazil), and are located in Jaguariaíva-PR, Ponta Grossa-PR, Rio Negrinho-SC and Três Barras-SC. The climate of these regions is temperate humid (Cfb), with mean annual precipitation of 1477mm, and maximum, mean and minimum temperatures of 24.3ºC, 17.9ºC e 12.7ºC. The biometric variables were assessed using inventory datasets (2006-2009), destructive sampling, bole analysis (disks), growth rings (stem coring), and specific gravity (X-ray densitometry). Soil samples (0-20cm) were collected on inventory plots, and climatic data were obtained from local weather stations. Site index (base age 10 years) were determined using bole disks, and growth patterns of all plots (m3ha-1), dry mass (Mgha-1), mean and current annual increments until 9th year were determined using stem coring and X-ray densitometry. Stand uniformity was evaluated using tree volume coefficient of variation within plots (CVV) and percentage of biomass for the 50% thinnest trees (PB50), from ages 2 to 9. Regions showed a wide range of soil physical and chemical properties, such as soil depth (30-140cm), organic matter levels (23 a 65g dm-3), clay content (20 a 85%), amount of N (500 a 5300kg ha-1), and amount of P (9 a 84kg ha-1). At 9 years old all the plots did not reached their maximum growth; and mean annual increment with bark (IMAc9), standing stem biomass and site index at base age 10 (IS10) ranged from 15 to 35m³ ha-1 year-1, 55 to 130Mg ha-1, and 12 a 19m, respectively, with higher values on Tres Barras region. This characterization was not possible to be detected before the 6th year, showing that early silvicultural and genetic decisions in Pinus need to be carefully considered. The productivity (IMAc9) was positively related with IS10, and both were related with higher levels of soil organic matter and available nitrogen, and with lower averages of minimum temperatures and water deficit. The most productive forests showed to be more uniform also (lower CVV and higher PB50), but confounded with superior genetic material. Therefore, the study corroborates with the role of nutrients, well drained soils, mild climatic conditions and low water deficit to explain the high yileds of P.taeda in Brazil, comparatively to its original region. Based on these results, studies of fertilization, genetic material and more frequent use of bole analysis, associated with X-ray densitometry, might be recommended for P. taeda.

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Džiaugytė, Emilija. "Arklių OCD (osteochondritis dissecans) kulno sąnario rentgeninių pakitimų analizė". Master's thesis, Lithuanian Academic Libraries Network (LABT), 2014. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2014~D_20140305_141607-53234.

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Tyrimas buvo atliekamas Lietuvos sveikatos mokslų universiteto, Veterinarijos akademijos, Stambiųjų gyvulių klinikoje. Pasirinktas tyrimo objektas, šlubuojančių arklių kulno sąnarys; metodika pirminis klinikinis tyrimas bei rentgenologinis tyrimas. Tiriamoji arklių grupė buvo sudaryta iš arklių, kurie buvo pasirinkti atsitiktiniu būdu. Įvairių veislių, lyčių ir amžiaus. Arklių kulno sąnarys yra vienas iš judamojo aparato – sudėtingas mechanizmas. Sudarytas iš kelių kaulų junginio ir sudaro vienaašį sudėtinį sąnarį (sraigtinis/sudėtinis). Blauzdikaulio, kulnies ir pėdos kaulų junginys. Šis sudėtinis judamasis mechanizmas dažnai paveikiamas Osteochondritis dissecans patologijos, kuris kelia arkliams skausmingą diskomforto jausmą ir gyvulys į šį dirgiklį atsako šlubavimu. Arklių kulno sąnario Osteochondritis dissecans dažniausiai diagnozuojamas sportiniams žirgams (56,53 proc.) dėl neadekvataus gyvulio jėgų išnaudojimo arba spartaus kumeliuko augimo ir nesubalansuoto jam tinkamo raciono. Taip pat nustatyta, jog kulno sąnario OCD diagnozuojama eržilams/kastratams (75 proc.) daugiau, nei kumelėms (25 proc.). Tyrimo metu paaiškėjo, jog kulno sąnario OCD pažeidimai lokalizavosi tiek pas eržilus/kastratus, tiek kumeles, daugiausiai kairiajame kulno sąnaryje (58,33 proc.), o dešinės kulno sąnario kojos pažeidimų aptikta procentine išraiška mažiau (33,33 proc.).
The study was conducted in Lithuanian University of Health Sciences, Veterinary Academy, Large Animal Clinic. The selected object of research was lame horse hock joint; method - initial clinical examination and radiographic analysis. The exploratory group of equines consisted of horses which were selected incidentally: various breeds, genders and age. Horse hock joint is one of the apparatus of locomotion which is a complex mechanism. It is composed of a compound of several bones to form a one-axis composite joint (screw/composite). It consists of combination of tibia, hock and foot bones. This complex locomotor mechanism is often affected by the pathology of Osteochondritis dissecans which causes painful feeling of discomfort for horses and consequently, they respond to this irritant by lameness. Horse Osteochondritis dissecans most often is diagnosed for racing and sports horses (56.53 percent) due to inadequate exploitation of animal strength, rapid growth of foal and improper diet. It was also found that OCD was diagnosed in stallions/geldings (75 percent) more than in mares (25 percent). The study revealed that OCD lesions localized to both stallions/geldings and mares, mostly on the left hock joint (58.33 percent), while the lesions of hock joint of the right leg were detected by a percentage less (33.33 percent).

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Torres, Geórgea Hermógenes Fernandes. "Associação de fraturas vertebrais moderadas e graves com menor densidade volumétrica trabecular na tíbia em mulheres idosas e menor densidade mineral óssea areal em fêmur em homens idosos da comunidade: São Paulo Ageing & Health study (SPAH)". Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/5/5166/tde-13022019-143204/.

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Introdução: A tomografia computadorizada periférica quantitativa de alta resolução (HR-pQCT) é um método diagnóstico que avalia microarquitetura óssea e estima resistência óssea por análise de elemento finito, facilitando a compreensão da fisiopatologia das fraturas. Objetivo: Avaliar associação de fraturas vertebrais moderadas e graves com parâmetros obtidos na HR-pQCT, escore trabecular ósseo (TBS) e densidade mineral óssea areal em idosos da comunidade. Métodos: Foram recrutados 276 idosos da coorte SPAH. Dados clínicos foram obtidos a partir de um questionário específico. A fratura vertebral (FV) foi avaliada por DXA-VFA utilizando-se o método semiquantitativo de Genant. HR-pQCT e DXA foram realizados no mesmo dia da coleta de sangue. O modelo de regressão logística foi realizado para verificar quais fatores foram associados de forma independente com a fratura vertebral moderada e grave. Resultados: Na tíbia, mulheres com FV moderada/grave apresentaram menor densidade mineral óssea volumétrica, menor número de trabéculas, menores valores dos parâmetros de resistência óssea e maior separação trabecular; e os homens apresentaram menor número de trabéculas, menor parâmetro de resistência óssea e maior separação trabecular. No rádio, as mulheres com FV moderada/grave tinham menor densidade mineral óssea volumétrica, espessura trabecular e cortical e menor valor do parâmetro de análise do elemento finito; e os homens tinham menor densidade mineral óssea volumétrica trabecular e menor valor de parâmetro de análise do elemento finito. Não foram observadas diferenças no TBS em ambos os sexos. A análise de regressão logística revelou que uma menor densidade mineral óssea volumétrica trabecular na tíbia em mulheres (OR: 0,980, 95% CI: 0,963-0,997, p = 0,022) e uma menor densidade mineral óssea areal do colo femoral e fêmur total em homens (OR: 0,002, IC 95%: 0-0,607, p = 0,033 e OR: 0,003, IC 95%: 0-0,623, p = 0,033) foram independentemente associados com FV moderada/grave. Conclusão: As imagens da HR-pQCT detectaram diferenças na microarquitetura óssea em mulheres idosas com FV moderada/grave independente de densidade mineral óssea areal e TBS por DXA; e HRpQCT pode ser uma ferramenta útil para avaliar o risco de fratura. Diferentemente, nos homens, a densidade mineral óssea areal do fêmur foi associada à FV moderada/grave; e a DXA continua sendo uma ferramenta importante para predizer a FV
Background: Many vertebral fractures (VF) occur in individuals classified by DXA as low risk for fragility fractures. Thus, the aim of this study was to verify the association between VF and peripheral bone microarchitecture and strength parameters using also high-resolution peripheral quantitative computed tomography (HR-pQCT) and axial bone microarchitecture by trabecular bone score (TBS). Study design: Cross-sectional study of 276 subjects aged >=65 years from SPAH cohort. Methods: Lateral scans of spine obtained from Vertebral Fracture Assessment by DXA were analyzed to assess VF. HR-pQCT was performed at radius and tibia. TBS was performed using DXA. Results: At tibia, women with Moderate/severe VF had lower volumetric bone density (vBMD), trabecular number (Tb.N), strength parameters and higher trabecular separation (Tb.Sp); and men had lower Tb.N, strength parameters and higher Tb.Sp. At radius, women with moderate/severe VF had lower v.BMD, trabecular and cortical thickness and strength parameters; and men had lower trabecular v.BMD and strength parameters. No differences were observed in TBS in both genders. Logistic regression analysis revealed that lower trabecular vBMD at tibia in women (OR: 0.980, 95%CI: 0.963-0.997, p = 0.022) and lower femoral neck aBMD and total hip in men (OR: 0.002, 95%CI: 0-0.607, p = 0.033 and OR: 0,003, IC 95%: 0-0,623, p = 0,033) were independently associated with VF. Conclusion: HR-pQCT images detected differences on bone microstructure in older women with moderate/severe VF independent of aBMD and TBS by DXA and HR-pQCT could be useful tool to assess fracture risk. Differently, in men femoral aBMD was associated with moderate/severe VF and DXA continue an important tool for predicting VF

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Baker, Mark Ralph. "Late radiation effects in radiotherapy : changes in the biomechanical properties of normal skin, and surgically produced lesions after X irradiation measured in vivo and in vitro". Thesis, University of Oxford, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335860.

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Strand-Tibbitts, Kristen. "Crystallographic Studies of Rrythrocruorin from Lumbricus Terrestris: a Dissertation". eScholarship@UMMS, 2004. http://escholarship.umassmed.edu/gsbs_diss/309.

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The viability of multicellular aerobic organisms requires the binding and transport of molecular oxygen from the atmosphere to sites of metabolism. In the earthworm, Lumbricus terrestris, erythrocruorins are freely dissolved multi-subunit protein complexes that serve the same functions as red blood cells The aims of this study were to 1) determine the overall arrangement of hemoglobin chains and non-hemoglobin chains in Lumbricus erythrocruorin, 2) determine the stereochemical determinants specifying erythrocruorin's hierarchical symmetry, and 3) investigate the molecular and chemical basis for the remarkable cooperative binding of ligands to earthworm hemoglobin. Erythrocruorin is a highly cooperative oxygen-carrying protein with Hill coefficients measured at some pH's as high as n = 7.9. Crystallographic analysis of the whole erythrocruorin molecule structure to 5.5 Å resolution reveals a hierarchical organization of 144 oxygen-binding polypeptides and 36 non-hemoglobin linker polypeptide chains. The hemoglobin chains are arranged in a novel dodecameric substructure at the periphery of the complex, whereas 36 linker chains comprise the inner core and projected triple-stranded, helical coiled-coil spokes towards the center of the complex. Interdigitation of these spokes appears crucial for stabilizing the complex. Crystallographic analysis of crystals from isolated hemoglobin chains provides greater detail (resolution = 2.6 Å) and complete atomic models for the hemoglobin polypeptides. Comparison of these models with other hemoglobins reveal unique features in the distal heme pocket, including large aromatic residues at the B10 position in three of the four hemoglobin chains. Aromatic residues at this position have been implicated in other hemoglobins to confer resistance to oxidation. Molecular interactions across each subunit include pH-dependent interactions that are consistent with the observed Bohr effect on oxygen binding. Specifically a π-cation interaction between an arginine of one subunit to a histidine of the opposing subunit is likely an important molecular switch in the allosteric transition from a low to high affInity ligand-binding state.

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