256 research outputs found

    Corneal Biomechanics in Ectatic Diseases: Refractive Surgery Implications.

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    BACKGROUND: Ectasia development occurs due to a chronic corneal biomechanical decompensation or weakness, resulting in stromal thinning and corneal protrusion. This leads to corneal steepening, increase in astigmatism, and irregularity. In corneal refractive surgery, the detection of mild forms of ectasia pre-operatively is essential to avoid post-operative progressive ectasia, which also depends on the impact of the procedure on the cornea. METHOD: The advent of 3D tomography is proven as a significant advancement to further characterize corneal shape beyond front surface topography, which is still relevant. While screening tests for ectasia had been limited to corneal shape (geometry) assessment, clinical biomechanical assessment has been possible since the introduction of the Ocular Response Analyzer (Reichert Ophthalmic Instruments, Buffalo, USA) in 2005 and the Corvis ST (Oculus Optikgerate GmbH, Wetzlar, Germany) in 2010. Direct clinical biomechanical evaluation is recognized as paramount, especially in detection of mild ectatic cases and characterization of the susceptibility for ectasia progression for any cornea. CONCLUSIONS: The purpose of this review is to describe the current state of clinical evaluation of corneal biomechanics, focusing on the most recent advances of commercially available instruments and also on future developments, such as Brillouin microscopy.(undefined)info:eu-repo/semantics/publishedVersio

    Modelling Deformations in Car Crash animation

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    In this paper, we present a prototype of a deformation engine to efficiently model and render the damaged structure of vehicles in crash scenarios. We introduce a novel system architecture to accelerate the computation, which is traditionally an extremely expensive task. We alter a rigid body simulator to predict trajectories of cars during a collision and formulate a correction procedure to estimate the deformations of the collapsed car structures within the contact area. Non-linear deformations are solved based on the principle of energy conservation. Large plastic deformations resulting from collisions are modelled as a weighted combination of deformation examples of beams which can be produced using classical mechanics

    Evaluation of Intereye Corneal Asymmetry in Patients with Keratoconus. A Scheimpflug Imaging Study

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    Purpose: To assess the correlation between keratoconus severity and intereye asymmetry of pachymetric data and posterior elevation values and to evaluate their combined accuracy in discriminating normal corneas from those with keratoconus. Methods: This study included 97 patients: 65 subjects with bilateral normal corneas (NC) and 32 with keratoconus (KC). Central corneal thickness (CCT), thinnest corneal thickness (ThCT) and posterior elevation (PE) at the thinnest point of the cornea were measured in both eyes using Scheimpflug imaging. Intereye asymmetry and its correlation with keratoconus severity were calculated for each variable. The area under the receiver operating characteristic curve (AUROC) was used to compare predictive accuracy of different variables for keratoconus. Results: In normal eyes, intereye differences were significantly lower compared with the keratoconus eyes (p<0.001, for CCT, ThCT and PE). There was a significant exponential correlation between disease severity and intereye asymmetry of steep keratometry (r(2) = 0.55, p<0.001), CCT (r(2) = 0.39, p<0.001), ThCT (r(2) = 0.48, p<0.001) and PE (r(2) = 0.64, p<0.001). After adjustment for keratoconus severity, asymmetry in thinnest pachymetry proved to be the best parameter to characterize intereye corneal asymmetry in keratoconus. This variable had high accuracy and significantly better discriminating ability (AUROC: 0.99) for KC than posterior elevation (AUROC: 0.96), ThCT (AUROC: 0.94) or CCT (AUROC: 0.92) alone. Conclusions: There is an increased intereye asymmetry in keratometry, pachymetry and posterior corneal elevation values in keratoconic patients compared to subjects with normal corneas. Keratoconus patients with more severe disease are also more asymmetric in their disease status which should be taken into account during clinical care

    Estudo do complexo valvar atrioventricular cardíaco esquerdo em búfalos (Bubalus bubalis) da raça Jafarabadi

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    Atrioventricular valve complex of 30 Jafarabadi water buffaloes, adult males were studied in this research with no heart diseases. The animals were obtained from a slaughterhouse in Brazilian State of Parana. The hearts were opened at the third portion affording access to the valve complex. The complexes had its area, number and type of tendinous cords submitted to analysis. The results showed that the complex is composed by two cusps and four accessory cusps, two or three papillary muscles in which 10-25 tendinous cords fix on the cusps that face the ventricle wall. The total area of the complex was on average 38.56cm², with a minimum of 24.96cm² and a maximum of 55.54cm². Statistically, no relation between the number of cords and the cusps' area where they are inserted or with the number of papillary muscle where they originated from was observed.Foram estudados os complexos valvares atrioventricular esquerdo de 30 búfalos da raça Jafarabadi, machos e adultos, sem alterações cardíacas, provenientes de abatedouros do Estado do Paraná. Os corações foram examinados em seu terço médio para acesso ao complexo valvar, que foi submetido a estudos de área, número e tipificação de cordas tendíneas. Os resultados demonstram que este complexo é formado por duas cúspides principais e quatro cúspides acessórias, apresentam em sua formação de 2-3 músculos papilares, nos quais se inserem de 10-25 cordas tendíneas, que se fixam em cúspides voltadas para a parede do ventrículo. A área total deste complexo apresenta uma média de 38,56cm² com um mínimo de 24,96cm² e um máximo de 55,54cm². Estatisticamente não há relação entre número de cordas e a área da cúspide onde estas estão inseridas, nem com o número de músculos papilares dos quais elas provem

    Modelagem dinâmica do uso e cobertura das terras para o controle da erosão na bacia hidrográfica do Rio Mogi-Guaçú e Pardo – São Paulo – Brasil.

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    O objetivo deste artigo é a modelagem da dinâmica do uso e cobertura das terras na Bacia-Hidrográfica dos Rios Mogi-Guaçú e Pardo no Estado de São Paulo. Ele foca a restauração dos serviços ecossistêmicos do controle da erosão. São descritos e analisados a dinâmica do uso e cobertura das terras, focados nas suas principais forças direcionadoras, tais como a legislação ambiental do país e as mudanças nos preços relativos favorecendo uma forte expansão do cultivo da cana-de-açúcar na região. Esta dinâmica tem importante impacto nas taxas de erosão cujas medidas metodológicas são apresentadas com os resultados obtidos. Para simular esta dinâmica foi desenvolvido um modelo seguindo a metodologia do MIMES. O algoritmo desenvolvido modela as mudanças do uso e cobertura das terras baseado principalmente na força das leis ambientais. Espera-se que esta dinâmica contribua para a restauração dos serviços ecossistêmicos da Bacia Hidrográfica

    Clinical and genetic characterisation of dystrophin-deficient muscular dystrophy in a family of Miniature Poodle dogs

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    Four full-sibling intact male Miniature Poodles were evaluated at 4–19 months of age. One was clinically normal and three were affected. All affected dogs were reluctant to exercise and had generalised muscle atrophy, a stiff gait and a markedly elevated serum creatine kinase activity. Two affected dogs also showed poor development, learning difficulties and episodes of abnormal behaviour. In these two dogs, investigations into forebrain structural and metabolic diseases were unremarkable; electromyography demonstrated fibrillation potentials and complex repetitive discharges in the infraspinatus, supraspinatus and epaxial muscles. Histopathological, immunohistochemical and immunoblotting analyses of muscle biopsies were consistent with dystrophin-deficient muscular dystrophy. DNA samples were obtained from all four full-sibling male Poodles, a healthy female littermate and the dam, which was clinically normal. Whole genome sequencing of one affected dog revealed a >5 Mb deletion on the X chromosome, encompassing the entire DMD gene. The exact deletion breakpoints could not be experimentally ascertained, but we confirmed that this region was deleted in all affected males, but not in the unaffected dogs. Quantitative polymerase chain reaction confirmed all three affected males were hemizygous for the mutant X chromosome, while the wildtype chromosome was observed in the unaffected male littermate. The female littermate and the dam were both heterozygous for the mutant chromosome. Forty-four Miniature Poodles from the general population were screened for the mutation and were homozygous for the wildtype chromosome. The finding represents a naturally-occurring mutation causing dystrophin-deficient muscular dystrophy in the dog

    Improving precision for detecting change in the shape of the cornea in patients with keratoconus

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    To investigate a method for precision analysis to discriminate true corneal change from measurement imprecision in keratoconus (KC). Thirty patients with KC and 30 healthy controls were included. Coefficients of repeatability and limits of agreement (LOA) were compared using multiple measurements for inter-observer and inter-device agreement with the Pentacam HR, Orbscan IIz, and Tomey Casia SS-1000. Correlation of repeated measurements was evaluated using a linear mixed effect model (also called random effect model). A formula was derived for the theoretical expected change in precision and compared with measured change. Correlation between measurements from the same eye was small (R = 0.13). The 99.73% LOA (3 SD) of the mean of three measurements, provided better precision than 95% LOA (2 SD) of single cut-off values as expected from statistical theory for uncorrelated measurements for evidence of a significant change in corneal shape in patients with keratoconus. This enabled the determination of cut-off values for the detection of true change in corneal shape. The mean of three repeated measurements will provide better precision when there is minimal correlation. Three (rather than two) standard deviations provides a precise estimate of the LOA within or between observers and can be used as a reliable measure for identifying stage-independent corneal shape changes (progression) in keratoconus

    Development of a planar multi-body model of the human knee joint

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    The aim of this work is to develop a dynamic model for the biological human knee joint. The model is formulated in the framework of multibody systems methodologies, as a system of two bodies, the femur and the tibia. For the purpose of describing the formulation, the relative motion of the tibia with respect to the femur is considered. Due to their higher stiffness compared to that of the articular cartilages, the femur and tibia are considered as rigid bodies. The femur and tibia cartilages are considered to be deformable structures with specific material characteristics. The rotation and gliding motions of the tibia relative to the femur can not be modeled with any conventional kinematic joint, but rather in terms of the action of the knee ligaments and potential contact between the bones. Based on medical imaging techniques, the femur and tibia profiles in the sagittal plane are extracted and used to define the interface geometric conditions for contact. When a contact is detected, a continuous non-linear contact force law is applied which calculates the contact forces developed at the interface as a function of the relative indentation between the two bodies. The four basic cruciate and collateral ligaments present in the knee are also taken into account in the proposed knee joint model, which are modeled as non-linear elastic springs. The forces produced in the ligaments, together with the contact forces, are introduced into the system’s equations of motion as external forces. In addition, an external force is applied on the center of mass of the tibia, in order to actuate the system mimicking a normal gait motion. Finally, numerical results obtained from computational simulations are used to address the assumptions and procedures adopted in this study.Fundação para a Ciência e a Tecnologia (FCT

    Proposta metodológica para subsidiar conservação e melhoramento genético da erva mate no sul do Brasil, baseada em grupos climáticos.

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    Além de interferir no fenótipo das plantas, o clima atua como uma grande força seletiva que interfere no genótipo e direciona a variação genética entre as populações e,por isso, deve ser considerado ao se explorar a variabilidade genética em programas de conservação e melhoramento. O objetivo deste trabalho foi determinar grupos climáticos onde a erva-mate (Ilex paraguariensisS.T. Hill) ocorre naturalmente no sul do Brasil. Para isto foi montada uma base de dados com 195 ocorrências. Os dados foram submetidos à análise multivariada, georreferenciamento e modelagem. Foram identificados, espacialmente, quatro grupos utilizando 11 parâmetros climáticos e também altitude. Embora os grupos apresentem contiguidade espacial, foi verificado que a erva-mate ocorre em vários substratos litológicos e em diferentes ecossistemas (Floresta Ombrófila Mista, Floresta Ombrófila Densa Montana, Floresta Estacional Decidual e Semidecidual eos biomas Pampa e Mata Atlântica). Esta adaptação indica uma grande plasticidade adaptativa da erva-mate, bem maior que a da Araucária, espécie companheira da erva mate em muitos ecossistemas. Os grupos isolados podem pertencer a populações geneticamente distintas. Os resultados destes estudos podem ser utilizados para apoiar programas de melhoramento e conservação de espécies, uso atual e futuro, considerando as mudanças climáticas e as pressões antrópicas

    PATOGENICIDADE DE ESPÉCIES DE Macrophomina COLETADAS DE PLANTAS DANINHAS EM FEIJÃO-CAUPI

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    [PT] A podridão de carvão causada por Macrophomina phaseolina é uma das principais doenças do feijão-caupi, causando perdas substanciais para os produtores. Na região semiárida do Brasil, o feijão-caupi é uma das alternativas utilizadas para rotação de culturas durante a entressafra do melão. Isso favorece a multiplicação de Macrophomina, uma vez que ambas as culturas são hospedeiras desse patógeno. O objetivo deste estudo foi verificar a patogenicidade em caupi de Macrophomina phaseolina e M. pseudophaseolina em caupi. Isolados de Macrophomina spp. obtidos das raízes de Trianthema portulacastrum e Boerhavia diffusa, espécies de plantas daninhas prevalentes em áreas de produção de melão no Nordeste brasileiro foram utilizadas neste estudo. O experimento foi realizado em casa de vegetação. Plantas de feijão-caupi 'Paulistinha' foram inoculados com 30 isolados de M. phaseolina, 30 isolados de M. pseudophaseolina e um isolado de referência de M. phaseolina obtido de raízes de feijão-caupi. Todos os isolados de Macrophomina foram patogênicos ao feijão-caupi, não havendo diferenças estatísticas entre as duas espécies de Macrophomina em relação à incidência e severidade da doença. Além disso, 65,2 e 100,0% dos isolados de M. phaseolina, e 56,2 e 92,8% dos isolados de M. pseudophaseolina, obtidos de T. portulacastrum e B. diffusa, respectivamente, foram tão severos ao feijão-caupi quanto o isolado de referência. Esses resultados enfatizam a necessidade de estabelecer práticas de manejo visando o controle de T. portucalastrum e B. diffusa nas áreas de produção de feijão-caupi, pois podem atuar como fontes de inóculo e sobrevivência para Macrophomina spp.[EN] Charcoal rot caused by Macrophomina phaseolina is a major cowpea disease causing substantial losses to growers. In the semi-arid region of Brazil, cowpea is one of the most widely used alternatives for crop rotation during the off-season of melon. This favors Macrophomina multiplication because both crops are hosts of this pathogen. The objective of this study was to verify the pathogenicity of Macrophomina phaseolina and M. pseudophaseolina on cowpea. The Macrophomina spp. isolates used were obtained from the roots of Trianthema portulacastrum and Boerhavia diffusa, weed species prevalent in melon production areas in North-east Brazilian The experiment was carried out in a greenhouse. Cowpea plants cv. Paulistinha' were inoculated with 30 M. phaseolina isolates, 30 M. pseudophaseolina isolates and a reference isolate of H. phaseolina obtained from cowpea roots. All Macrophomina isolates were able to cause disease on cowpea and there were no statistical differences between both Macrophomina species regarding disease incidence and severity. Moreover, 65.2 and 100.0% of the M. phaseolina isolates, and 56.2 and 92.8% of the M. pseudophaseolina isolates, obtained from T. portulacastrum and B. diffusa, respectively, were as severe to cowpea as the M. phaseolina reference isolate from cowpea. These results emphasize the need to establish management practices aiming to control T. portucalastrum and B. diffusa from cowpea production areas, as they can act as potential sources of inoculum and survival for Macrophomina spp.This study was partially financed by the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior -Brazil (CAPES) -Finance Code 001 and by the Conselho Nacional de desenvolvimento Cientifico e Tecnologico (CNPq).Sales Jr., R.; Nogueira, A.; Mitsa Paiva Negreiros, A.; Rodrigues, T.; De Queiroz, M.; Armengol Fortí, J. (2020). PATHOGENICITY OF Macrophomina SPECIES COLLECTED FROM WEEDS IN COWPEA. Revista Caatinga. 33(2):395-401. https://doi.org/10.1590/1983-21252020v33n212rcS395401332Ambrósio, M. M. Q., Dantas, A. C. A., Martínez-Perez, E., Medeiros, A. C., Nunes, G. H. S., & Picó, M. B. (2015). Screening a variable germplasm collection of Cucumis melo L. for seedling resistance to Macrophomina phaseolina. Euphytica, 206(2), 287-300. doi:10.1007/s10681-015-1452-xFreitas, F. C. L., Medeiros, V. F. L. P., Grangeiro, L. C., Silva, M. G. O., Nascimento, P. G. M. L., & Nunes, G. H. (2009). Interferência de plantas daninhas na cultura do feijão-caupi. Planta Daninha, 27(2), 241-247. doi:10.1590/s0100-83582009000200005Gomes-Silva, F., Almeida, C. M. A., Silva, A. G., Leão, M. P. C., Silva, K. P., Oliveira, L. G., … Lima, V. L. M. (2017). Genetic Diversity of Isolates of Macrophomina phaseolina Associated with Cowpea from Brazil Semi-Arid Region. Journal of Agricultural Science, 9(11), 112. doi:10.5539/jas.v9n11p112Gupta, G. K., Sharma, S. K., & Ramteke, R. (2012). Biology, Epidemiology and Management of the Pathogenic Fungus Macrophomina phaseolina (Tassi) Goid with Special Reference to Charcoal Rot of Soybean (Glycine max (L.) Merrill). Journal of Phytopathology, 160(4), 167-180. doi:10.1111/j.1439-0434.2012.01884.xKaur, S., Dhillon, G. S., Brar, S. K., Vallad, G. E., Chand, R., & Chauhan, V. B. (2012). Emerging phytopathogenMacrophomina phaseolina: biology, economic importance and current diagnostic trends. Critical Reviews in Microbiology, 38(2), 136-151. doi:10.3109/1040841x.2011.640977Machado, A. R., Pinho, D. B., Soares, D. J., Gomes, A. A. M., & Pereira, O. L. (2018). Bayesian analyses of five gene regions reveal a new phylogenetic species of Macrophomina associated with charcoal rot on oilseed crops in Brazil. European Journal of Plant Pathology, 153(1), 89-100. doi:10.1007/s10658-018-1545-1Mbaye, N., Mame, P. S., Ndiaga, C., & Ibrahima, N. (2015). Is the recently described Macrophomina pseudophaseolina pathogenically different from Macrophomina phaseolina? African Journal of Microbiology Research, 9(45), 2232-2238. doi:10.5897/ajmr2015.7742Negreiros, A. M. P., Sales Júnior, R., León, M., Melo, N. J., Michereff, S. J., Ambrósio, M. M., … Armengol, J. (2019). Identification and pathogenicity of Macrophomina species collected from weeds in melon fields in Northeastern Brazil. Journal of Phytopathology, 167(6), 326-337. doi:10.1111/jph.12801Negreiros, A. M. P., Júnior, R. S., Rodrigues, A. P. M. S., León, M., & Armengol, J. (2019). Prevalent weeds collected from cucurbit fields in Northeastern Brazil reveal new species diversity in the genusMonosporascus. Annals of Applied Biology, 174(3), 349-363. doi:10.1111/aab.12493Ramos, H. M. M., Bastos, E. A., Andrade Júnior, A. S. de, & Marouelli, W. A. (2012). Estratégias ótimas de irrigação do feijão‑caupi para produção de grãos verdes. Pesquisa Agropecuária Brasileira, 47(4), 576-583. doi:10.1590/s0100-204x2012000400014Reis, E. M., Boaretto, C., & Danelli, A. L. D. (2014). Macrophomina phaseolina: density and longevity of microsclerotia in soybean root tissues and free on the soil, and competitive saprophytic ability. Summa Phytopathologica, 40(2), 128-133. doi:10.1590/0100-5405/1921Rocha, M. de M., Carvalho, K. J. M. de, Freire Filho, F. R., Lopes, Â. C. de A., Gomes, R. L. F., & Sousa, I. da S. (2009). Controle genético do comprimento do pedúnculo em feijão-caupi. Pesquisa Agropecuária Brasileira, 44(3), 270-275. doi:10.1590/s0100-204x2009000300008Sales Junior, R., Oliveira, O. F. de, Medeiros, É. V. de, Guimarães, I. M., Correia, K. C., & Michereff, S. J. (2012). Ervas daninhas como hospedeiras alternativas de patógenos causadores do colapso do meloeiro. Revista Ciência Agronômica, 43(1), 195-198. doi:10.1590/s1806-66902012000100024Sales Júnior, R., Rodrigues, A. P. M. dos S., Negreiros, A. M. P., Ambrósio, M. M. de Q., Barboza, H. da S., & Beltrán, R. (2019). WEEDS AS POTENTIAL HOSTS FOR FUNGAL ROOT PATHOGENS OF WATERMELON. Revista Caatinga, 32(1), 1-6. doi:10.1590/1983-21252019v32n101rcFrancisco, de A. S. e S., & Carlos, A. V. de A. (2016). The Assistat Software Version 7.7 and its use in the analysis of experimental data. African Journal of Agricultural Research, 11(39), 3733-3740. doi:10.5897/ajar2016.11522Silva, M. G. O. da, Freitas, F. C. L. de, Negreiros, M. Z. de, Mesquita, H. C. de, Santana, F. A. O. de, & Lima, M. F. P. de. (2013). Manejo de plantas daninhas na cultura da melancia nos sistemas de plantio direto e convencional. Horticultura Brasileira, 31(3), 494-499. doi:10.1590/s0102-05362013000300025Zhao, L., Cai, J., He, W., & Zhang, Y. (2019). Macrophomina vaccinii sp. nov. causing blueberry stem blight in China. MycoKeys, 55, 1-14. doi:10.3897/mycokeys.55.3501
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