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Sample records for tomografia axial computarizada

  1. Dose profile measurement in computerized axial tomography equipment using thermoluminescent dosemeters; Medicion del perfil de dosis en equipos de tomografia axial computarizada usando dosimetros termoluminiscentes

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    Azorin V, J.C.; Falcony, C.; Azorin N, J. [Centro de Investigacion en Ciencia y Tecnologia Avanzada, IPN, 07000 Mexico D.F. (Mexico)

    2000-07-01

    In this work are presented the results about measuring the radiation dose profile in two equipment of computerized axial tomography (Tac). Thermoluminescent dosemeters (Dtl) of LiF, Mg, Cu, P + Ptfe in form of disks were used which were developed and made in Mexico. The results showed that Dtl are appropriated for these type of studies. (Author)

  2. Analysis of fetal dose in CT procedures; Analisis de dosis fetal en procedimientos de tomografia computarizada

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    Ortiz Torres, A.; Plazas, M. C.

    2006-07-01

    It is the miracle of the life, that sublime formation, the given more beautiful gift for heaven's sake to our to exist, and it is consequently our responsibility to look after their protection and care. Today in day the quantity of radiation absorbed by the fetus in the treatments for radiodiagnostic, mainly in the procedures of on-line axial tomography, the fetus absorbs a considerable dose of radiation and the questions generated regarding if these doses, bear to a risk of malformations or if it is necessary the interruption of the pregnancy is very frequent. In most of the cases, the treatment with ionizing radiations that it is beneficial for the mother, is only indirectly it for the fetus that is exposed to a risk. The possibility that a fetus or a small boy contract cancer caused by the radiation it can be three times superior to that of the population in general, of there the importance of analyzing the goods of the prenatal irradiation and the main agents to consider for the estimate of the magnitude of the risk of the exhibitions in uterus. In the different circumstances in that these can happen in treatments of on-line axial tomography computerized. (Author)

  3. Resultados de biopsia guiada por tomografía axial computarizada en el síndrome de destrucción vertebral, evaluados en dos instituciones distintas

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    Barón Zarate-Kalfopulos

    2013-01-01

    Full Text Available OBJETIVO: Comparar resultados de biopsias vertebrales guiadas por tomografía axial computarizada, reportados por dos servicios de Anatomía Patológica distintos en pacientes con síndrome de destrucción vertebral para confirmar confiabilidad y utilidad en el diagnóstico. MÉTODOS: Se obtuvieron muestras de tejido de 21 pacientes en el periodo comprendido del 1 de marzo al 15 de julio del 2011 con el diagnóstico del síndrome de destrucción vertebral y a quienes se les realizó biopsia guiada por tomografía axial computarizada. Las muestras se enviaron en forma cegada a dos servicios de patología distintos. Los resultados fueron analizados con el método de comparación de dos proporciones. RESULTADOS: 14 pacientes fueron del género masculino (67% y 7 del femenino (23%, edades de 28-82, con afección principalmente lumbar (48% y torácica (38%; afectados en una vértebra en 62%, en dos en un 33% y en 3 o más niveles en 5%. Las vértebras más afectadas fueron L1, L2 y L3 (12/30 [40%], T4 (3/30 [10%] y T9 (3/30 [10%]. Los resultados se agruparon en categorías: 1. Osteomielitis (9/21 [43%], 2. Tumores (7/21 [33%], 3. Metástasis (3/21 [14%], 4. Tejido normal (2/21 [10%], 5. Inflamación (0/21 [0%], 6. Muestra inadecuada (0/21 [0%], 7. Mal de Pott (0/21 [0%]. CONCLUSIONES: De acuerdo a los valores de Z obtenidos mediante la prueba de comparación de dos proporciones no se encontró diferencia significativa entre los resultados reportados por dos los dos servicios de patología en el síndrome estudiado, determinándose que esta parte del proceso es confiable y útil en un 90%.

  4. Immediate adverse reactions to intravenous iodinated contrast media in computed tomography Reacciones adversas inmediatas al contraste yodado intravenoso en tomografía computarizada Reações adversas imediatas ao contraste iodado intravenoso em tomografia computadorizada

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    Beatriz Cavalcanti Juchem

    2007-02-01

    Full Text Available This exploratory-descriptive, non-experimental quantitative research aimed to learn about immediate adverse reactions to intravenous iodinated contrast media in hospitalized patients submitted to computed tomography at a teaching hospital in the South of Brazil. During the study period, all adverse reactions showed mild intensity, at a frequency of 12.5% with ionic iodinated contrast media, and 1% with non-ionic contrast agent. The extravasation of contrast occurred in 2.2% of the injections in a peripheral vein without complications in any of the cases. The results are within the limits cited in international literature and suggest that tomography service professionals should know their own rates of adverse reactions to iodinated contrast agent, as well as the conditions in which they occur, in order to obtain evidence to evaluate the respective care delivery processes.Investigación cuantitativa del tipo exploratorio-descriptivo, de carácter no experimental. El objetivo consistía en conocer las reacciones adversas inmediatas al contraste yodado intravenoso en pacientes internados, sometidos a tomografía computarizada en un hospital escuela del sur de Brasil. Durante el período del estudio, todas las reacciones adversas tuvieron intensidad leve y una frecuencia del 12,5% con la utilización del contraste yodado iónico, y 1% con contraste no iónico. La extravasación del contraste ocurrió en un 2,2% de las inyecciones en vena periférica, no ocasionando complicaciones en ninguno de los casos. Los índices evidenciados en el presente estudio se mantuvieron dentro de los límites que constan en la revisión de literatura y, entre las recomendaciones, se sugiere que los servicios de tomografía conozcan los propios índices de reacciones adversas al contraste yodado y las condiciones en que ocurren, con la finalidad de obtener evidencias para evaluación de los respectivos procesos asistenciales.Pesquisa quantitativa, explorat

  5. Measurement and analyses of spectral noise power in computed tomography; Medida y analisis del espectro de potencias del ruido en imagenes de tomografia computarizada

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    Castro Tejero, P.; Garayoa Roca, J.

    2014-07-01

    Noise is an important feature of image quality. The standard deviation of pixel value in a uniform region has been frequently used as a metric to characterize noise. However, this measure does not provide any information about the noise spatial distribution. A more complete description is given by the Noise Power Spectrum (NPS) which provides both the amount and the spatial correlation of noise. The objective of the present work is to present a methodology and a computing tool to obtain the NPS, in order to analyze its components and study their behaviour for computed tomography (TC) images. Our results show that the major contribution to NPS is a random source for all the explored working conditions. The structural component is constrained to the low frequency region, where it can be as important as the random component. Moreover, we observe that the reconstruction filter and the acquisition technique, axial or helical, have a clear impact on the image noise. (Author)

  6. Evaluation method of reference levels of radiation diagnostic in computerized tomography; Metodo de evaluacion de niveles de referencia de radiodiagnostico en tomografia computarizada

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    Flores, Walter; Borges, Jose C. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Programa de Engenharia Nuclear; Mota, Helvecio C. [Instituto de Radioprotecao e Dosimetria (IRD), Rio de Janeiro, RJ (Brazil). Dept. de Fisica Medica

    2000-07-01

    The computerized tomography (CT) is a complex technique, with many parameters to be selected and protocols of quality control not standardized, connected with high doses in the patients. In this work a simple methodology is developed, to evaluate levels of reference of diagnosis in computerized tomography using the concept of Multiple Scan Average Dose (MSAD), recently adopted by the Ministry of Health of Brazil. This methodology, can be used in the routine of inspection of evaluation of radiological safety in medical radiation diagnostics, executed by the Department of Medical Physics of the Institute of Radiation Protection and Dosimetry and by the sanitary authorities in Brazil. In order to evaluate this dosimeter magnitude the distribution of dose it was studied the dose distribution obtained trough a profile of dose measured in the axial axis of a simulator(phantom) of water with thermoluminescent dosimeters, TLD-100, for three techniques of examination by CT. The magnitude MSAD was evaluated by means of two different methods. In first, it was evaluated for an only cut, and in the second for multiple cuts. This last method presents/displays to be more practical and adapted to be applied in the routine of evaluation of reference levels, with TLDs.

  7. Análise do diâmetro transverso do processo odontoide com uso da tomografia computadorizada Análisis del diámetro transverso del proceso odontoides con uso de la tomografía computarizada Analysis of the transverse diameter in the odontoid process by computerized tomography

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    Fábio Kazuo Soejima

    2010-12-01

    Full Text Available INTRODUÇÃO: o diâmetro reduzido do odontoide é um desafio para o cirurgião no planejamento pré-operatório e escolha na fixação da fratura com um ou dois parafusos. OBJETIVO: analisar a medida do diâmetro transverso (DT do processo odontoide por meio da tomografia computadorizada para o planejamento pré-operatório da osteossíntese com um ou dois parafusos. MÉTODOS: foram analisadas 79 tomografias computadorizadas cervicais de pacientes adultos, sem deformidades congênitas ou queixas de dor em coluna cervical alta, atendidos em uma clínica privada de Blumenau - Santa Catarina. RESULTADOS: as médias de idade não revelaram diferença estatisticamente significante entre os sexos, mas observou-se diferença estatisticamente significante entre as médias do DT do odontoide de homens e mulheres. A média do diâmetro transverso nos homens foi de 10,29 mm, e nas mulheres de 9,39 mm. CONCLUSÃO: a tomografia computadorizada mostrou-se útil para a medição do diâmetro transverso do processo odontoide. A fixação com um parafuso cortical de 3,5 mm seria possível em todos os casos analisados e a fixação com dois parafusos seria possível em 83,9% dos homens e 62,5% das mulheres.INTRODUCCIÓN: el diámetro reducido de la odontoides es un desafío para el cirujano en la planificación pre-operatoria y de la elección en la fijación de la fractura con uno o dos tornillos. OBJETIVO: analizar la medida del diámetro transverso (DT del proceso odontoides, por medio de la tomografía computarizada para el planeamiento pre-operatorio de la osteosíntesis con uno o dos tornillos. MÉTODOS: fueron analizadas 79 tomografías computarizadas cervicales de pacientes adultos, sin deformidades congénitas o reclamos de dolor en la columna cervical alta, atendidos en una clínica privada de Blumenau - Santa Catarina, Brasil. RESULTADOS: los promedios de edad no revelaron diferencia estadísticamente significante entre los sexos, pero se observ

  8. Auxílio da tomografia computadorizada no planejamento pré-operatório de pacientes portadores de escoliose idiopática do adolescente Auxilio de la tomografía computarizada en el plan preoperatorio de pacientes portadores de escoliosis idiopática del adolescente Computed tomography aid in preoperative planning of patients with adolescent idiopathic scoliosis

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    Rodrigo Rezende

    2010-03-01

    Full Text Available A escoliose idiopática do adolescente (EIA é uma doença diagnosticada no início da puberdade. Ela apresenta etiologia indefinida e caracteriza-se pelo desvio lateral da coluna vertebral maior que 10°, associado à rotação do corpo vertebral. O uso de instrumentação de terceira geração produziu um melhor resultado na correção da curva do que as técnicas anteriores. Porém, ainda existem dificuldades técnicas no momento da passagem e da escolha dos parafusos pediculares, devido à angulação e ao diâmetro dos pedículos vertebrais. Apesar de apresentar vantagens, essa técnica não é isenta de riscos e complicações, necessitando de uma maior curva de aprendizado pelo médico-cirurgião, bem como de um adequado planejamento pré-operatório. Até o momento, não há na literatura relato sobre a utilização da tomografia computadorizada no auxílio do planejamento cirúrgico de pacientes com escoliose. Diante do exposto, objetivamos, no presente estudo, descrever uma técnica de planejamento pré-operatório, com o auxílio da tomografia computadorizada para a fixação da coluna em pacientes com escoliose idiopática do adolescente, especificando a angulação e o diâmetro dos pedículos vertebrais, o que poderá auxiliar o médico-cirurgião no momento da fixação.La escoliosis idiopática en el adolescente (EIA es una enfermedad diagnosticada en el inicio de la pubertad. Esta presenta una etiología indefinida y es caracterizada por el desvío lateral de la columna vertebral por encima de los diez grados asociados a la rotación del cuerpo vertebral. El uso de instrumentación de tercera generación produjo un mejor resultado en la corrección de la curva comparado con las técnicas anteriores. Sin embargo, existen dificultades técnicas en el momento del paso y de escoger los tornillos pediculares debido a la angulación y al diámetro de los pedículos vertebrales. A pesar de presentar ventajas, esta técnica no est

  9. Study of the relationship and importance of clinical semiology, axial computed tomography and electroneuromyography in lumbar radioculopathies Estudo da relação e da importância entre a semiologia clínica, tomografia axial computadorizada e eletroneuromiografia nas radiculopatias lombares

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    Emílio Cezar Mamede Murade

    2002-12-01

    Full Text Available The authors evaluated forty-three patients with clinical suspect of lumbar radiculopathy caused by disk hernia, concerning to clinical semiology, computed tomography and electromyography were studied and their correlations. The clinical semiology was altered in 100,0% of the patients, the computed tomography in 90,7% and the electromyography in 88,7%. The correlation among the three exams didn´t show any prevalency among any of the possible associations. The authors emphasize the importance of clinical semiology, computed tomography and electromyography for a more accurate diagnosis of lumbar radiculopathy following by disk hernia.Os autores estudaram 43 pacientes com suspeita clínica de radiculopatia lombar, causada por hérnia de disco, relacionando os achados da semiologia clínica, tomografia axial computadorizada e eletroneuromiografia, entre si. A semiologia clínica estava alterada em 100,0% dos pacientes, a tomografia axial computadorizada em 90,7% e a eletroneuromiografia em 88,7%. A correlação entre os três exames não mostrou prevalência entre nenhuma associação. Os autores enfatizam a importância da semiologia clínica, tomografia axial computadorizada e eletroneuromiografia para maior exatidão diagnóstica das radiculopatias lombares por hérnia de disco.

  10. Limitaciones de la tomografia axial computada en la localizacion de quistes hidatidicos abdominales en pacientes con confirmacion inmunodiagnostica

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    E. A. Guarnera

    1984-12-01

    Full Text Available Se describe el aporte de la prueba de doble disfusión arco 5 (DD5 al diagnóstico de la hidatidosis en dos pacientes con operaciones previas. En una de ellas, asintomática, la reacción positiva a los cinco años de su última intervención quirúrgica por hidatidosis, permitió diagnosticar la presencia de quistes cuya localización abdominal fue establecida por la tomografía axial computada (TAC. En el otro caso, sintomático, aunque operado de hidatidosis nueve años antes, la positividad a la DD5 confirmó la etiología de la enfermedad que se había sospechado por centellografía, TAC y su historia clínica. En ambos casos, sin embargo, se hallaron en el acto quirúrgico otros quistes abdominales cuyas imágenes no habían sido reveladas en los estudios a los que se las había sometido.

  11. X-ray detectors in axial computed tomography development; Sensori di radiazioni X negli sviluppi della tomografia assiale computerizzata

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    Gislon, R.; Imperiali, F. [ENEA, Centro Ricerche Casaccia, Rome (Italy). Dip. Innovazione

    1996-12-01

    The increase of potentially of axial computed tomography as a non destructive investigation method in industrial field is particularly tied to the development of the X-rays detectors. The transition from the first gas ionization detectors to the last semiconductor detectors has indeed dramatically increased the performances of tomographic systems. In this report, after a quick analysis of fundamental principles of tomography, the most significant parameters for a detector to be used in a tomographic system are reviewed. The examination of the principal kinds of detectors that have been up to now used, with their working schemes, allows to delineate their characteristics and so to compare them with the ideal detector sketched above. The necessity of using high definition arrays brings to put into evidence the inadequacy of both gas and liquid ionization detectors and also of those types of light conversion devices which utilize for signal amplification a photomultiplier tube. Systems based on charge coupled devices or on a light conversion obtained with semiconductor photodiode arrays are definitely to be preferred. The progress of the last years in microelectronic technologies has brought great improvements in this field.

  12. Aplicação das técnicas de tomografia axial computorizada e ressonância magnética no diagnóstico de hérnia discal em cão

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    Cabral, Nádia Torres Militão

    2017-01-01

    Dissertação de Mestrado Integrado em Medicina Veterinária O objetivo deste trabalho consistiu numa descrição dos princípios físicos da tomografia axial computorizada (TAC) e da ressonância magnética (RM) e das caraterísticas imagiológicas das hérnias discais na espécie canina. Ao longo do trabalho, é feita uma revisão bibliográfica acerca da anatomia da coluna vertebral, abordagem ao paciente com suspeita de doença da coluna vertebral e considerações fisiopatológicas relativas ...

  13. Correlação entre hipótese diagnóstica e laudo de tomografia axial computadorizada craniana Correlation between diagnostic hypothesis and result of cranial computed axial tomography

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    Edison Matos Nóvak

    2001-09-01

    Full Text Available Para avaliar a utilização da tomografia axial computadorizada craniana (TC em nosso meio, analisamos as solicitações de 367 exames consecutivos no período compreendido entre 07/1995 e 07/1996. Houve ampla variação da faixa etária, com média de 31,7 ± 22,9 anos. As especialidades que mais solicitaram o exame foram: Neurologia (36,2%, Pronto Atendimento (17,4%, Neuropediatria (16,9% e Clínica Médica (5,9%. As indicações mais frequentes para o exame foram: convulsão (30%, cefaléia (26,2%, déficit motor (20,2% e redução do nível de consciência (16,9%. As "hipóteses" aventadas com maior frequência foram: afastar lesão estrutural (9,0%, acidente vascular não discriminado (8,2% e neurocisticercose (8,2%. O laudo da TC foi normal em 50,4% dos exames. Os laudos anormais mais frequentes foram: hidrocefalia (5,4%, acidente vascular isquêmico (5,4% e neoplasia (3,5%. As maiores taxas de achados normais foram encontradas nas "hipóteses" de cefaléia (94,4%, convulsão (71,4% e afastar lesão estrutural (66,7%. Os maiores índices de acerto entre hipótese e laudo foram encontrados nas situações de "afastar lesões estruturais" (66,7%, hidrocefalia (50%, acidente vascular cerebral isquêmico (50% e hematoma (50%. Concluimos que a utilização de um recurso auxiliar de diagnóstico como a TC cumpre melhor ainda a sua função se o requisitante do exame preencher com clareza e detalhamento o pedido do exame.The use of computed axial tomography (CT in the investigation of neurologic disorders is attractive for his disponibility in the health services. However, the indications of the exam and the correlation with the clinical features has not been frequently studied. We study correlation between the requests of CT and the findings reported by the radiologist, in 367 exams performed from 07/1995 to 07/ 1996. The mean age was 31.7 ± 22.9 years. The CT were requested in decrescent order of frequency by the Services of Neurology (36

  14. Limitaciones de la tomografia axial computada en la localizacion de quistes hidatidicos abdominales en pacientes con confirmacion inmunodiagnostica Limitations of computerized axial tomography in the localization of abdominal hydatid cysts in patients with immunodiagnostic confirmation

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    E. A. Guarnera

    1984-12-01

    Full Text Available Se describe el aporte de la prueba de doble disfusión arco 5 (DD5 al diagnóstico de la hidatidosis en dos pacientes con operaciones previas. En una de ellas, asintomática, la reacción positiva a los cinco años de su última intervención quirúrgica por hidatidosis, permitió diagnosticar la presencia de quistes cuya localización abdominal fue establecida por la tomografía axial computada (TAC. En el otro caso, sintomático, aunque operado de hidatidosis nueve años antes, la positividad a la DD5 confirmó la etiología de la enfermedad que se había sospechado por centellografía, TAC y su historia clínica. En ambos casos, sin embargo, se hallaron en el acto quirúrgico otros quistes abdominales cuyas imágenes no habían sido reveladas en los estudios a los que se las había sometido.The contribution of the arc 5 double diffusion test (DD5 to the diagnosis of hydatidosis in two patients with previous surgery for this parasitic infection is described. In one of the patients, who was asymptomatic, the diagnosis was established on the basis of a positive DD5 reaction five years after her last surgical intervention. The abdominal location of cysts was revealed by computerized axial tomography (CAT. The other patient had been operated on for hydatidosis nine years earlier and showed symptoms. Positivity to the DD5 test confirmed the etiology of the disease, which had been suspected on the basis of her clinical history and the findings of scintillographic and CAT studies. In both cases, however, other abdominal cysts were found at surgery whose images had not been revealed in the previous studies.

  15. Utilidad de la angiografía por tomografía axial computarizada en la evaluación anatómica de los pacientes pediátricos con cardiopatías congénitas Utility of computed axial tomography angiography in anatomic evaluation of pediatric patients with congenital heart diseases

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    Walter Mosquera A

    2007-12-01

    Full Text Available Antecedentes: aunque el ecocardiograma y el cateterismo cardiaco se utilizan como primera instancia en el diagnóstico de cardiopatías congénitas, la angiografía por tomografía computarizada es un examen mínimamente invasivo que, mediante imágenes en dos/tres dimensiones en tiempo real, favorece el adecuado abordaje diagnóstico de pacientes con este tipo de patologías, en quienes se requiere una evaluación rápida y precisa de su anatomía extracardiaca. Objetivo: describir la experiencia institucional (agosto 2005-2006 en el uso de la angiografía por tomografía computarizada como método diagnóstico complementario en la evaluación de los pacientes pediátricos con cardiopatías congénitas. Método: estudio descriptivo - serie de casos. Se evaluaron pacientes pediátricos con diagnóstico clínico y ecocardiográfico de cardiopatías congénitas que se estudiaron con el escanógrafo General Electric Multislice Lightspeed/16 cortes. Resultados: mediante angiografía por tomografía, se evaluaron 58 pacientes de 2,4 ± 4,03 años de edad, con historia de cardiopatías congénitas. El 33,8% tuvo diagnóstico de atresia pulmonar, el 6,7% de atresia tricúspide, el 13,5% de doble tracto de salida del ventrículo derecho, el 11, 8% de tetralogía de Fallot, el 11,8% de coartación aórtica, el 3,3% de arco aórtico interrumpido; el 10,3% de ductus arterioso persistente, el 6,7% de drenaje venoso anómalo y el 5,1% de transposición de grandes arterias. Se obtuvieron imágenes de alta calidad que permitieron evaluar de forma precisa la anatomía vascular. Conclusiones: en los pacientes descritos, la angiografía por tomografía resultó ser una herramienta útil en el abordaje diagnóstico ya que permitió reconstruir su anatomía de manera tridimensional. Se requieren nuevos estudios que permitan evaluar la sensibilidad, la especificidad y el nivel de concordancia de esta técnica frente a otros métodos diagnósticos invasivos

  16. Dose evaluation in diagnostic for computerized tomography; Evaluacion de dosis en diagnostico por tomografia computarizada

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    Flores, W.; Borges, J.C.; Mota, H. [Universidad Federal de Rio de Janeiro, PEN/COPPE/UFRJ. Caixa Postal 68509. 21945-970 Rio de Janeiro (Brazil)

    1998-12-31

    The patients which are subjected to computerized tomography tests are exposed to relatively high doses given as result doses on organs that are not matter to test. It was realized a dose levels raising in patients subjected to tests by T C, utilizing to measure this magnitude, TLD-100 thermoluminescent dosemeters which were put directly on the patient, in eye regions, thyroid, breast and navel; founding doses fluctuating between 29.10-49.39 mGy in organs examined and dose values between 0.21-29.10 mGy for organs that no matter to test. The applications of ionizing radiations in medicine do not have dose limits, but paying attention to the radiological protection optimization principle, it is recommended the use of clothes to anti-rays protection for zones not examined, getting with this to reduce the level doses as low as possible, without this to diminish the test quality. (Author)

  17. Computed Tomography. Evolution, technical principles and applications; Tomografia computarizada. Evolucion, principios tecnicos y aplicaciones

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    Calzado, A.; Geleijns, J.

    2010-07-01

    Computed tomography has become one of the most commonly used diagnostic techniques. Since its clinical introduction in 1971, subsequent developments have led to the emergence of new indications in different medical specialties. This paper reviews the evolution of art; essential characteristics of CT scanners are described and different application modalities in diagnosis are reviewed as well. (Author).

  18. Chondrosarcoma of the hyoid bone: computed tomography findings; Condrosarcoma de hioides: hallazgos en tomografia computarizada

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    Saez, J.; Gallego, J. a.; Fuster, M. J. [Hospital General Universitario de Elche. Alicante (Spain)

    2001-07-01

    Chondrosarcoma of the hyoid bone is a rare entity, only 10 cases of which have been reported in the literature to date. the case we present involved a 24-year-old man who complained of progressive adynophagia and a mass in anterior neck. Computed tomography revealed a low-attenuation mas attached to the left horn of the hyoid bone. The lesion was excised and was diagnosed as a grade II chondrosarcoma. The patient remains asymptomatic 10 years after the operation. (Author) 11 refs.

  19. Variation of surface dose in CT; Variacion de la dosis superficial en Tomografia Computarizada

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    Aviles Lucas, P.; Castellano, I. A.; Dance, D. R.; Vano Carruana, E.; Prieto Martin, C.

    2003-07-01

    An experimental study has been made of the variations of the air kerma-length product at the surface of a phantom exposed in a CT scanner using clinical parameters. the effect of patient size, position within the gantry plane and beam-shaping filter type was studied using three different elliptical phantoms. A dose reduction technique based on a sinusoidal tube current modulation system was also investigated. the result of the variation of the surface dose was analysed for the case of CT fluoroscopy procedures. The surface air kerma-length product was shown to be independent of phantom size (within experimental error) but decreases as the surface moves vertically away from the iso centre. The major contributor to this variation the beam-shaping filter. The possibility of underestimating the surface dose if an AAPM body phantom is used (a 36% increase for the head phantom) is an indirect result of the previous conclusion when applied to CT fluoroscopy. This highlights the importance of considering the size and position of the patient when measuring the does. Finally, when the tube current modulation system was used, the maximum surface dose reduction was 18%. (Author) 23 refs.

  20. CT Assessment of the axial deviation of the femoral and tibial prosthetic components in total knee arthroplasty; Valutazione con Tomografia Computerizzata della rotazione delle componenti femorale e tibiale nell'artroprotesi totale del ginocchio

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    Rimondi, E.; Molinari, M.; Moio, A.; Busacca, M. [Istituto Ortopedico Rizzoli, Bologna (Italy). Servizio di Diagnostica per Immagini; Trentani, F.; Trentani, P.; Tigani, D. [Istituto Ortopedico Rizzoli, Bologna (Italy). VII Div.; Nigrosoli, M. [Istituto Ortopedico Rizzoli, Bologna (Italy). IV Div.

    2000-06-01

    CT assessment of the axial deviation of the femoral and tibial prosthetic components in total knee arthroplasty. From January to July 1999, 17 patients, 10 males and 7 females, mean age 66 years (standard deviation plus or minus 4) were examined after total knee arthroplasty. Exclusion criteria were prosthesis loosening and severe (equal or superior to 7 degrees) varus o valgus deviation. All patients were examined with knee radiography in the standing position completed by axial projection of patella and by CT scanning. It was used a modification of Berger technique and carried out comparative CT scans extended lower limbs and acquisitions perpendicular to the mechanical axis of the knee, from the femoral supracondylar region down to the plane crossing the distal end of the tibial prosthetic component. Reference lines were then drawn electronically on given scanning planes to reckon the axial deviation of the femoral and tibial prosthetic components. Six patients, one female and 5 males with normal rotational values of femoral and tibial prosthetic components presented no clinical symptoms. Eight patients, 4 females and 4 males, with abnormal values presented the following clinical symptoms: medial impingement, (incomplete) dislocation patella, and lateral instability. One female patient with a normal rotational value of femoral prosthetic component and an altered value of tibial prosthetic component presented medial impingement. Finally two patients, one female and one male, were absolutely asymptomatic although the rotational values of the two prosthetic components were beyond the normal range. Total knee arthroplasty is presently a standard treatment for many conditions involving this joint. There are several possible postoperative complications, namely fractures, dislocations (a)septic losening and femoropatellar instability. The latter condition is the most frequent complication among implant failures and is caused by bad orientation of the femoral and tibial

  1. Costo-efectividad de la tomografía computarizada y la ecografía en el diagnóstico de apendicitis

    Directory of Open Access Journals (Sweden)

    Álvaro Sanabria

    2008-03-01

    Conclusiones. Los métodos diagnósticos por imágenes en los casos de duda diagnóstica de apendicitis, son más costo-efectivos que el examen clínico para definir la conducta terapéutica. La tomografía axial computarizada ofrece una mejor relación costo-efectividad en el sistema de salud prepagada y es casi equiparable a la ecografía para el plan obligatorio de salud.

  2. Study of Coronary Arteries by Means of Multidetector CT; Estudio de las arterias coronarias mediante tomografia computarizada multidetector

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, G. C.; Costas, M. I.; Delgado, C.; Velasco, M.; Tardaguila, F. [Hospital POVISA. Vigo. Pontevedra (Spain)

    2004-07-01

    Radiological study of coronary arteries has undergone major advances,especially with the incorporation of new CT multidetectors which afford temporary spatial resolution sufficient for the acquisition of high-quality images and diagnoses concerning various coronary artery abnormalities. The technique is described in terms of both facilitating data within a procedure making use of beta-blockers to slow heart rate and postprocess image reconstruction. Accordingly, our experience with a 16-detector CT and its clinical applications are illustrated. (Author)

  3. Computed Tomography findings in Fournier's gangrene; Hallazgos en tomografia computarizada de la grangrena de Fournier

    Energy Technology Data Exchange (ETDEWEB)

    Isusi, M.; Campo, M.; Oleaga, L.; Grande, J.; Grande, D. [Hospital de Barsurto. Bilbao (Spain)

    2000-07-01

    To assess the utility of computed tomography (CT) as an imaging technique in the diagnosis and determination of the extension of Fournier's gangrene (FG). We report the cases of six patients who had been clinically diagnosed as having FG, CT, enhanced by oral and intravenous contrast media, was performed in all the patients. All six patients presented soft tissue masses and gas in the scrotal region, which were also detected in the perineal region in five. In two patients, the gas extended toward anterior abdominal wall and in one of them, it also observed in anterior and posterior para renal space. The major predisposing factors were diabetes and alcoholism and the most common triggering factor was urologic disease. CT confirms the existence of FG and aids in assessing its extension and, in some cases, in identifying the underlying cause. (Author) 15 refs.

  4. Criptococose pulmonar: aspectos na tomografia computadorizada

    Directory of Open Access Journals (Sweden)

    Silva Ana Carina Gamboa da

    2003-01-01

    Full Text Available A criptococose pulmonar é uma doença causada pelo Criptococcus neoformans, um fungo unimórfico que possui distribuição mundial, existindo na mesma forma tanto no seu habitat natural quanto em animais e humanos. A doença possui apresentações clínica e patológica variáveis e pode manifestar-se tanto em pacientes com a imunidade normal como em imunocomprometidos, que representam a maioria dos casos. Neste trabalho são analisados os aspectos encontrados nas tomografias computadorizadas do tórax de 14 pacientes com criptococose pulmonar confirmada. Os achados mais freqüentes na tomografia do tórax foram as massas e os nódulos pulmonares. Outros aspectos observados foram as áreas de escavação, as consolidações, o espessamento do interstício peribroncovascular e o reticulado difuso. Massa pulmonar foi o achado isolado mais comum (64,2%, seguido dos nódulos isolados ou múltiplos (35,7%. Doença pulmonar difusa foi vista em apenas 14,2% dos casos. Os lobos superiores foram os mais comprometidos, sendo a doença mais comum nas regiões anteriores. A tomografia do tórax permitiu avaliar com precisão o grau de comprometimento do parênquima pulmonar.

  5. REVISIÓN DE LAS EVALUACIONES ADAPTATIVAS COMPUTARIZADAS (CAT

    Directory of Open Access Journals (Sweden)

    Ruber López

    2015-06-01

    Full Text Available En este artículo presentamos una revisión de las Evaluaciones Adaptativas Computarizadas. A diferencia de los test convencionales, estas evaluaciones plantean un examen adaptado a las necesidades y capacidades de cada uno de los evaluados, lo cual redunda en una mejor experiencia para el evaluado y en una mayor precisión del resultado. Las evaluaciones adaptativas se fundamentan en la teoría de respuesta a ítems, que define las directrices y condiciones para que este tipo de pruebas sea posible. A partir de esta teoría, surgen distintos modelos que permiten modelar diferentes rasgos de los evaluados y la relación de estos con la probabilidad de acertar un ítem dado. Para llevar a cabo el proceso de evaluación, un test adaptativo debe estar conformado de un banco de ítems, un método que permita la selección de estos y un criterio de terminación. Todos estos componentes articulan la prueba y la ayudan a concretarse adecuadamente. AbstractThis paper is a review of the Computerized Adaptive Testing Process. Unlike conventional tests, these assessments propose a test adapted to every examinee’s needs and capabilities, which results in a better experience for those assessed and a more accurate score. Adaptive assessments are based on item response theory, which defines the guidelines and conditions for such tests to be carried out. From this theory, different models that allow the repositioning of different traits of the examinees and their relationship with the probability to succeed in a given item, arise. To complete the assessment process, an adaptive test should consist of a set of items, a method which allows the selection of these and a termination criterion. All the aforementioned components articulate the test and help to properly materialize it.

  6. Axial myopathy

    DEFF Research Database (Denmark)

    Witting, Nanna; Andersen, Linda K; Vissing, John

    2016-01-01

    Classically, myopathies are categorized according to limb or cranial nerve muscle affection, but with the growing use of magnetic resonance imaging it has become evident that many well-known myopathies have significant involvement of the axial musculature. New disease entities with selective axial...

  7. Estudo de caso de oferta induzindo a demanda: o caso da oferta de exames de imagem (tomografia axial computadorizada e ressonância magnética na Unimed-Manaus Case study of supply induced demand: the case of provision of imaging scans (computed tomography and magnetic resonance at Unimed-Manaus

    Directory of Open Access Journals (Sweden)

    Edson de Oliveira Andrade

    2011-04-01

    Full Text Available OBJETIVO: Apresentar a experiência de uma operadora de plano de saúde (Unimed-Manaus na cidade de Manaus, Estado do Amazonas, com o credenciamento de serviços de imagem e a indução de demanda pela oferta dos novos serviços (Lei de Roemer. MÉTODOS: Trata-se de uma pesquisa de caráter retrospectivo, com estudo de série temporal, abordando o período de janeiro de 1998 a junho de 2004, lapso de tempo em que ocorreu a implantação dos serviços de tomografia computadorizada e da ressonância magnética no âmbito dos serviços oferecidos por aquele plano de saúde. A análise estatística consistiu em uma parte descritiva e uma inferencial, sendo esta última utilizando teste paramétrico de média (teste t de Student e ANOVA e o teste de correlação de Pearson. Foi adotado um alfa de 5% e um intervalo de confiança de 95%. RESULTADOS: Foi possível identificar na Unimed-Manaus que a oferta de novos serviços de imagem foi capaz de, por si só, gerar um aumento da demanda do serviço caracterizando o fenômeno descrito por Roemer. CONCLUSÃO: Os resultados deste trabalho ressaltam a necessidade de se estar atento ao fato de que a oferta de novos serviços no setor da saúde poderá acarretar, por si só, um aumento de sua utilização sem que haja uma demanda real.OBJECTIVE: To present the experience of a health plan operator (Unimed-Manaus in Manaus, Amazonas, Brazil, with the accreditation of imaging services and the demand induced by the supply of new services (Roemer's Law. METHODS: This is a retrospective work studying a time series covering the period from January 1998 to June 2004, in which the computed tomography and the magnetic resonance imaging services were implemented as part of the services offered by that health plan operator. Statistical analysis consisted of a descriptive and an inferential part, with the latter using a mean parametric test (Student T-test and ANOVA and the Pearson correlation test. A 5% alpha and a 95

  8. Evaluation of doses received by pediatric and adult patients undergoing to CT exams; Evaluacion de la dosis recibida por pacientes adultos y pediatricos en examenes de tomografia computarizada

    Energy Technology Data Exchange (ETDEWEB)

    Lavie, Maria F. Jimenez; Tejeda, Adalberto Machado, E-mail: felicia@cceem.sld.cu, E-mail: adalberto@cceem.sld.cu [Centro para el Control Estatal de Medicamentos, Equipos y Dispositivos Medicos (CECMED), La Habana (Cuba); Otano, Anisia; Zuniga, Dora Maya [Hospital Pediatrico Centro Habana (Cuba); Perdomo, Jorge Hing; Rodriguez, Gustavo Guadarrama [Hospital Docente Clinico Quirurgico Freyre Andrade, La Habana (Cuba)

    2013-07-01

    This paper aims to evaluated the dose to adult and pediatric patients due to the execution of tests CT scan of head, chest and abdomen, as well as establish a comparative analysis between these results and protocols involving employees to begin a process optimization in the practice.

  9. Pulmonary artery aneurysm in Bechcet's disease: helical computed tomography study; Aneurisma de la arteria pulmonar en la enfermedad de Behcet. Estudio con tomografia computarizada helicoidal

    Energy Technology Data Exchange (ETDEWEB)

    Munoz, J.; Caballero, P.; Olivera, M. J.; Cajal, M. L.; Caniego, J. L. [Hospital de la Princesa. Iniversidad Autonoma. Madrid (Spain)

    2000-07-01

    Behcet's disease is a vasculitis of unknown etiology that affects arteries and veins of different sizes and can be associated with pulmonary artery aneurysms. We report the case of a patient with Behcet's disease and a pulmonary artery aneurysm who was studied by means of plain chest X ray, helical computed tomography and pulmonary arteriography. Helical computed tomography is a reliable technique for the diagnosis and follow-up of these patients. (Author) 9 refs.

  10. Measurement and analysis of noise power spectrum of computerized tomography in images; Medida y analysis del espectro de potencias del ruido en imagenes de tomografia computarizada

    Energy Technology Data Exchange (ETDEWEB)

    Castro Tejero, P.; Garayoa Roca, J.

    2013-07-01

    This paper examines the implementation of the spectrum of powers of the noise, NPS, as metric to characterize the noise, both in magnitude and in texture, for CT scans. The NPS found show that you for convolution filters that assume a greater softening in the reconstructed image, spectrum is concentrated in the low frequencies, while for filters sharp, the spectrum extends to high frequencies. In the analyzed cases, there is a low frequency component, largely due to the structure-borne noise, which can be a potential negative effect on the detectability of injuries. (Author)

  11. Determination of the thickness of radiation equipment computed tomography (CT); Determinacion del espesor de radiacion en equipos de tomografia computarizada (TC)

    Energy Technology Data Exchange (ETDEWEB)

    Gago Gomez, P.; Ayala Lazaro, R.; Gonzalez Ruiz, C.; Hurtado Sanchez, A.; Sierra Diaz, F.

    2011-07-01

    The cutting thickness determination radiologically diagnosed TC teams is usually done directly irradiating a film situated at the height of radiological isocenter, with collimated beams to cut thicknesses nominal and valuing the size of these same in plaque. This test is usually done by measuring directly on the surface irradiated. This affects the measurement accuracy when the tolerance established for this test in the Spanish Protocol as is the uncertainty associated scale. Can be assessed simultaneously moving the table and adjusted the nominal value.

  12. Epiploic appendicitis and omental infarction. Findings in the ultrasonography and computerized tomography; Apendicitis epiploica e infarto omental. Hallazgos en ecografia y tomografia computarizada

    Energy Technology Data Exchange (ETDEWEB)

    Migule, A.; Ripolles, T.; Martinez, M. J.; Morote, V.; Ruiz, A. [Hospital Universitario Dr. Peset. Valencia (Spain)

    2001-07-01

    Describe the findings in the ultrasonography and computerized tomography (CT) of the omental infarction and epiploic appendicitis. The clinical and radiological findings of the patients diagnosed in our hospital with epiploic appendicitis or omental infarctions between August 1994 and March 2001 were assessed retrospectively. We found a high incidence (42 cases) of these two diseases: 30 patients with diagnosis of epiploic appendicitis and 12 with the diagnosis of omental infarction. Four patients were treated surgically, while the remaining 38 were conservatively, without posterior complications. The ultrasonography and CT images is characteristics. making it possible to make a diagnosis of epiploic appendicitis or omental infarction with certainty. It is not necessary to make a differential diagnosis between the two entities because their prognosis and treatment are similar. Their incidence is much more frequent than that previously published. (Author) 19 refs.

  13. Study of the effect of the variation of automatic exposure control in computed tomography; Estudio del efecto de la variacion del control automatico de exposicion en tomografia computarizada

    Energy Technology Data Exchange (ETDEWEB)

    Nersissian, D. Y.; Capeleti, F. F.; Furquin, T. A. C.; Melo, C. S.

    2011-07-01

    Teams computed tomography (CT) contain the current automatic control of exposure (CAE) which vary from the current X-ray tube in clinical protocols and deliver lower doses than those with fixed current. Alone is not enough control of dose, you need an acceptable image quality ensuring an accurate diagnosis. The TC regulate the flow of two ways: by considering the thickness of the patient and the attenuation by different tissues that intercept the x-ray Besides the advantage, there is the responsibility of proper use of different CAE systems, which require particular knowledge of each manufacturer of the CT.

  14. Adaptation of a real time `microfocus` X-ray system for computerized tomography; Adaptacao de um sistema de raios-X `microfocus` em tempo real para tomografia computarizada

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Julio L.; Lopes, Joana R.; Lopes, Ricardo T.; Oliveira, Luis F. de [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia

    1997-10-01

    A tomographic system has been settled up by adapting a real time microfocus radiographic system through an image digitization schedule. This system aimed to obtain CT of small samples in an acceptable data acquisition time, which was hardly reduced compared to traditional X-ray micro tomographic system that employs conventional X-ray sources and detectors. Several CTs ware made using small samples with holes, milk tooth and fruits, in order to verify the performance of the system (spatial resolution, density resolution and image quality). (author). 7 refs., 10 figs.

  15. Comparison of ultrasonography and computed tomography in the diagnosis of acute appendicitis; Comparacion de la ecografia y la tomografia computarizada en el diagnostico de la apendicitis aguda

    Energy Technology Data Exchange (ETDEWEB)

    Cura, J. L. del; Oleaga, L.; Grande, D.; Farina, M. A.; Isusi, M. [Hospital de Basurto. Bilbao (Spain)

    2001-07-01

    The compare the efficacy of ultrasonography and computed tomography (CT) in cases of suspected appendicitis. To study to what extent age, sex and habits of the patients, as well as the clinical context, influence the diagnostic yield of these two technique. Over a one-year period, 152 patients underwent ultrasonography and CT because of the clinical suspicion of appendicitis. The studies were carried out independently, and the results of each in terms of the presence or absence of appendicitis were unknown to the specialists performing the other. The final diagnoses were established by surgical treatment or clinical follow-up. The sensitivity of CT for the diagnosis of appendicitis was 82%, the specificity was 95%, the positive predictive value was 93%, the negative predictive value was 87% and the reliability was 90%. Ultrasonography has a sensitivity of 83%, a specificity of 97%, a positive predictive value of 95%, a negative predictive value of 88% and a reliability of 91%. Ultrasound was more efficient in patients in which there was a high clinical suspicion and in children, while the results with CT were better in patients in which the clinical diagnosis was less clear. The incidence of false negatives and positives was higher with ultrasound, while CT was more frequently able to identify a normal appendix. Sex and habits had no influence on the respective efficacies, although the performance of ultrasound was simplified in thin patients and that of CT in obese individuals. Ultrasonography and CT are highly reliable in cases of suspected appendicitis, especially when this diagnosis is conformed. Ultrasound is recommended as the technique of choice in children and in patients in which the clinical suspicion is strong. The yield of CT is somewhat greater when the clinical signs and symptoms are less clear. However, the efficacy of both techniques ultimately depends on the expertise of the specialist who interprets them. (Author) 62 refs.

  16. Rectal contrast-enhanced computed tomography in the diagnosis of acute appendicitis; Tomografia computarizada con contraste rectal en el diagnostico de la apendicitis aguda

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    To assess the efficacy and utility of computed tomography (CT) in the diagnosis of appendicitis, and to evaluate the reliability of CT findings in right iliac fossa in the confirmation or exclusion of this diagnosis. Over a one-year period, 152 patients presenting clinical signs of appendicitis underwent CT scans. The images were reviewed by two radiologists who considered whether the appendix was normal or enlarged and the existence of other signs of appendicitis for the purpose of determining whether or not the patient presented appendicitis. The definitive diagnoses were established by surgery or by clinical follow-up. The sensitivity of CT for the diagnosis of appendicitis was 81.8%, the specificity was 95.3%, the positive predictive value was 93.1%, the negative predictive value was 87.2% and the reliability was 89.9%. The signs of appendicitis observed were: appendicoliths (sensitivity 30.3% and specificity 98.8%), fluid collections (sensitivity 19.7%, specificity 96.5%), cecal enlargement (sensitivity 21.2%, specificity 97.7%), inflammation of pericecal fat (sensitivity 72.7%, specificity 90.7%), fascial thickening (sensitivity 48.5%, specificity 91.9%) and an appendix measuring more than 6 mm (sensitivity 78.8%, specificity 94.3%). Adenopathy and free peritoneal fluid were not significantly related to appendicitis. The presence of a normal appendix filled with air or contrast material had an elevated negative predictive value with respect to appendicitis. In 35 of the 94 cases with negative CT scans, the images suggested alternative diagnoses. CT is a highly reliable diagnostic method for appendicitis. The observation of an appendix filled with air or contrast material has an elevated negative predictive value. The presence of appendicoliths has an elevated positive predictive value. (Author) 29 refs.

  17. A study of the dose modulation systems in two multislice CT scanners; Estudio de los sistemas de modulacion de dosis en dos equipos de tomografia computarizada multicorte

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez Giron, I.; Valverde Moran, J.; Mendez Fernandez, R.; Aramburu Nunez, D.; Nunez Villavicencio, C.; Calzado Cantera, A.

    2009-07-01

    Multislice computed tomography (TCMC) is a technique that for its gradual introduction and the spectacular increase in its indications in clinical practice represents the main contribution to the collective dose in diagnostic radiology. It is essential to optimize the protocols maintaining doses as low as possible without affecting the diagnostic quality of images. Automatic tube current modulation systems are a tool currently available in all CT scanners. They adapt the tube current to morphological characteristics of the patient and the anatomical area under study. The aim of this work has been to analyze two scanners from the same manufacturer and featuring similar geometry by assessing the relative dose differences and image quality. Modulation systems of general use can decrease the dose in a 20-60% with a reduction in the signal to noise ratio between 6% and 37%. Dedicated cardiac-CT modulation system gave rise to high relative differences (36-40%) even when varying the heart rate. Significant changes in image quality were not appreciated though the motion of the heart has not been simulated in this study. (Author) 14 refs.

  18. Utility of helical computed tomography in the management of renal colic; Utilidad de la tomografia computarizada helicoidal en el manejo del colico nefritico

    Energy Technology Data Exchange (ETDEWEB)

    Martel, J.; Cruz, R. de la; Rengifo, D. [Fundacion Hospital Alcorcon. Madrid (Spain)

    2000-07-01

    In recent years, noncontrast helical computed tomography has modified the imaging techniques employed in the management of patients who arrive in the emergency service presenting signs of renal colic. Based on the literature and our own experience with 140 patients who complained of pain suggestive of a colic probably due to stone disease, we review the radiological features of this entity and discuss the utility of the technique in confirming the diagnosis, predicting the clinical course and detecting other diseases that present with identical symptomatology. (Author) 20 refs.

  19. Characterization of radiation beam filtration in computerized tomography equipments. Dosimetric influence; Caracterizacion de la filtracion del haz de radiacion en equipos de tomografia computarizada. Influencia dosimetrica

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Tortosa, M.; Echevarne, M. [Universitat Rovira i Virgili (Spain); Calzado Cantera, A. [Universidad Complutense (Spain)

    2000-07-01

    The basic dosimetric quantities used in CT to assess doses to patient are the computed tomography dose index (CTDI) which can be determined either from measurements free-in-air or in standard head or body phantoms. CTDI values measured for different type of scanners can present high differences (up to a factor two). These differences are mainly due to differences in quality of the X ray beam as a consequence of differences in physical filtration. The filters used varied widely according to the manufacturer and model of scanner. Some scanners use a single fixed absorber, while others utilize two or more absorbers devoted specifically to anatomical areas (body or head) or different kind of examinations (pediatric,.). A good knowledge of the features of these absorbers (equivalent thickness and shape) is very useful in order to compare dose and to optimize the procedures for clinical use. however, such information is not always available and the assessment of the total filtration after installation of the scanners is seldom tackled. Dose measurements have been performed in order to determine the beam filtration and its influence on dose for a sample of seven third generation CT scanners. Measurements were conducted according to the ImPACT protocol, prepared specifically for the CT Scanner Dose Survey, in which we were participating. The investigated parameters were the half value layer and CT dose indexes (measured free-in-air and within phantoms), and an operational description of the shaping filters after selectable FOV values, as well. (Author) 32 refs.

  20. Analysis of FPGA filter in Computed Tomography Images for Radioactive Dose Reduction; Analisis del Filtro FPGA en Imagenes de Tomografia Computarizada para la Reduccion de Dosis Radiactiva

    Energy Technology Data Exchange (ETDEWEB)

    Parcero, E.; Vidal, V.; Verdu, G.; Arnal, J.; Mayo, P.

    2014-07-01

    In this study, different filtering methods are compared on an image of mini-MIAS database (consisting of a collection of mammographic images). Methods employees are PGFM (Peer Group Fuzzy Metric), NDF (Non-linear Diffusion Method) a combination of these two, and FPGA (Fuzzy Peer Group Average). (Author)

  1. Axial spondyloarthritis.

    Science.gov (United States)

    Sieper, Joachim; Braun, Jürgen; Dougados, Maxime; Baeten, Dominique

    2015-07-09

    The term axial spondyloarthritis covers both non-radiographic disease and radiographic disease (also known as ankylosing spondylitis). Some studies have been performed to investigate the prevalence of axial spondyloarthritis, although most are limited to patients with radiographic disease. A strong genetic association has been shown between axial spondyloarthritis and human leukocyte antigen-B27 (HLA-B27), but the pathogenetic role of HLA-B27 has not yet been clarified. Tumour necrosis factor (TNF), IL-17, IL-23 and downstream pathways also seem to be important - based on the good results of therapies directed against these molecules - but their exact role in the inflammatory process is also not yet clear. Elucidating the interaction between osteoproliferation and inflammation will be crucial for the prevention of long-term structural damage of the bone. The development of new criteria for classification, diagnosis and screening of patients with axial spondyloarthritis will enable earlier intervention for this chronic inflammatory disease. MRI has become an important tool for the early detection of axial spondyloarthritis. NSAIDs and TNF blockers are effective therapies, including in the early non-radiographic stage. Therapeutic blockade of IL-17 or IL-23 seems to be a promising new treatment option. Tools for measuring quality of life in axial spondyloarthritis have become relevant to assess the impact that the disease has on patients. These diagnostic and therapeutic advances will continue to change the management of axial spondyloarthritis, and new insights into the disease pathogenesis will hopefully accelerate this process. For an illustrated summary of this Primer, visit: http://go.nature.com/51b1af.

  2. Fiabilidad de la lectura computarizada de un electrocardiógrafo

    OpenAIRE

    Martínez Sola, Encarnación María

    2018-01-01

    [EN] El electrocardiograma (ECG) es una de las técnicas diagnósticas más utilizada para la detección de enfermedades cardiovasculares, ya que es una prueba no invasiva, rápida, de bajo coste y con alto valor diagnóstico. Dicha prueba es realizada por el colectivo enfermero el cual debe llevar a cabo su interpretación inicial. Para facilitar dicha tarea, existe la lectura computarizada (LC) de los electrocardiógrafos. ¿Pero es realmente fiable? Con el fin de responder a dicha pregunta se an...

  3. La tomografía computarizada cone beam en la ortodoncia, ortopedia facial y funcional

    OpenAIRE

    Roque-Torres, Gina D; Meneses-López, Abraham; Norberto Bóscolo, Frab; De Almeida, Solange María; Haiter Neto, Francisco

    2015-01-01

    La Tomografía Computarizada Cone Beam (TCCB) es una tecnología en rápido desarrollo que proporciona imágenes de alta resolución espacial del complejo craneofacial en tres dimensiones (3D). Durante la última década, el número de publicaciones relacionadas a la TCCB en la literatura se ha incrementado de manera significativa, pero la cuestión fundamental es si esta tecnología conduce a mejores resultados. La TCCB y su aplicación en la ortodoncia es muy importante ya que esta nueva tecnología va...

  4. Cefalometría 3D mediante tomografía computarizada de haz de cono

    OpenAIRE

    Montoto González, Gloria

    2015-01-01

    La cefalometría es una herramienta clínica de investigación esencial en la ortodoncia. Las imágenes en dos dimensiones tienen una serie de desventajas entre ellas la falta de perspectiva, errores en la proyección, superposición de estructuras, artefactos en la imagen, magnificación o errores de posición de la cabeza. La tomografía computarizada de haz de cono (TCCB) nos ofrece una alternativa a sistemas tradicionales de TC con ciertas ventajas como menor radiación y menor coste. OBJET...

  5. Primeros pasos en la posturografía dinámica computarizada

    Directory of Open Access Journals (Sweden)

    Cristina CORDERO-CIVANTOS

    2018-01-01

    Full Text Available Introducción y objetivo: La posturografía dinámica computarizada (CDP es una técnica que nos va a permitir cuantificar de forma objetiva, como las diferentes patologías afectan la estabilidad postural de los pacientes y su evolución. Metodología: revisión narrativa. Resultados: En este trabajo vamos a repasar como se realizan y analizan las diferentes pruebas de la CDP; y su utilidad diagnóstica y terapéutica en la práctica otorrinolaringológica. Discusión y conclusiones: La posturografía dinámica computarizada es una prueba diagnóstico-terapéutica que permite cuantificar de forma objetiva y reproducible la estabilidad del paciente. Y aporta información relevante para planificar el tratamiento rehabilitador, así como para monitorizar su evolución.

  6. Tomografia computadorizada no seguimento de pacientes com tumores intracranianos

    Directory of Open Access Journals (Sweden)

    Gilberto Machado de Almeida

    1981-03-01

    Full Text Available A tomografia computadorizada tem grande valor no controle dos pacientes com tumores cerebrais. Imediatamente após o ato cirúrgico pode ser útil para avaliar a retirada do processo expansivo ou para comprovar a área atingida. Nos primeiros dias após a intervenção tem sido indicada principalmente quando há piora do quadro neurológico. Nestas condições, o exame permite verificar a existência de ar, edema, hematoma, desvios ventriculares e hidrocéfalo. Os dados fornecidos são mais precisos que os obtidos com outros exames neuror-radiológicos ou com a medida contínua da pressão intracraniana, métodos menos inócuos. A longo prazo a tomografia permite o diagnóstico precoce de recidivas, a avaliação da eficácia de tratamentos radio ou quimioterápicos e o controle do hidrocéfalo. Ainda não é possível fazer o diagnóstico diferencial entre radio-necrose e recidiva tumoral.

  7. Light axial vector mesons

    Science.gov (United States)

    Chen, Kan; Pang, Cheng-Qun; Liu, Xiang; Matsuki, Takayuki

    2015-04-01

    Inspired by the abundant experimental observation of axial-vector states, we study whether the observed axial-vector states can be categorized into the conventional axial-vector meson family. In this paper we carry out an analysis based on the mass spectra and two-body Okubo-Zweig-Iizuka-allowed decays. Besides testing the possible axial-vector meson assignments, we also predict abundant information for their decays and the properties of some missing axial-vector mesons, which are valuable for further experimental exploration of the observed and predicted axial-vector mesons.

  8. Modelización computarizada de sistemas físicos. Su incidencia en el proceso educativo

    Directory of Open Access Journals (Sweden)

    Francisco J. Marcos

    2005-01-01

    Full Text Available El trabajo de desarrollo tecnológico que se expone constituye una propuesta de utilización de la informática como instrumento activo, capaz de posibilitar el proceso enseñanza-aprendizaje, como así también la experimentación sobre leyes y principios físicos en condiciones ideales, mediante una adecuada selección de variables. El desarrollo de modelos y dispositivos logrados por medio de una metodología computarizada apropiada, compatible con la actividad científica aplicable al proceso educativo, permite efectivizar el estudio de sistemas físicos desde la perspectiva de la Física como disciplina básica y favorece la aplicación de nuevas estrategias tendientes a superar la incidencia negativa de los preconceptos en el aprendizaje.

  9. Fabricación de biomodelos tridimensionales odontológicos a partir de tomografías computarizadas

    Directory of Open Access Journals (Sweden)

    Fabián Villena

    2017-10-01

    Full Text Available Este manuscrito tiene por objetivo establecer un flujo de trabajo para la construcción de biomodelos tridimensionales mediante la técnica de fabricación con filamento fundido. Se describen las características de tomografías computarizadas en formato DICOM, la generación de un modelo tridimensional desde los archivos DICOM y finalmente la manufactura (impresión, por medio de la tecnología de fabricación con filamento fundido. A través de este protocolo de trabajo es posible generar biomodelos tridimensionales paciente-específicos a bajo costo, donde la precisión de la tecnología con filamento fundido es confrontable con otros sistemas más costosos.

  10. Experimental measurement of the scatter fraction in skull and body CT for teams 64- slice computed tomography; Medida experimental de la fraccion de dispersion TC en craneo y cuerpo para equipo de tomografia computarizada de 64 cortes

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, G.; Haro, G.; Herrador, M.

    2011-07-01

    Different formalisms for the calculation of shielding in Cf equipment, the proposed document 147 of NCRP are widely accepted. Of the three methods mentioned in the protocol, two involve the use of two independent factor a of equipment, called scatter fraction CT in skull and body. Interestingly, the experimental measurement of the same, especially in those models following the publication of the document, which are also coincides with the highest number of detector channels and overall a greater radiation beam in the z axis.

  11. On-line course as tools for radiation protection training in patients. A practical case in computerized tomography; El Aula Virtual como herramienta para la formacion en PR del paciente; caso practico en tomografia computarizada

    Energy Technology Data Exchange (ETDEWEB)

    Medina Campos, J.; Fernandez Tallon, J.; Busca Suau, J.; Baro Casanovas, J.

    2006-07-01

    The rise in ionizing radiation applications within the field of diagnostics, with the corresponding increase in both number and doses received by patients, requires adequate resources for education and training in radiological protection. In is quite difficult to assemble professionals at a specific place to carry out training. However, the use of Information and Communication Technologies (IT) makes it possible to carry out training. However, the use of Information and Communication Technologies (IT) makes it possible to carry out training through Internet in an effective, easy and amusing way (e-learning). An on-line course of patient radiological protection and quality control in computer tomography has been developed aimed at professionals that use these diagnostic techniques. The course has been run twice in the period 2005-2006. The course is found on an Internet-accessible Virtual Campus, which allows access to multimedia contents, communication between students and instructors and follow-up of students performance. Final evaluation is done on-line and successfully passing the course counts for 8.9 credits in the Continuous Education Programme of Spanish Health Systems. (Author)

  12. The high-grade interpolator: a means for enhancing the resolution of helical computed tomography images of the lung; El interpolador de alto orden: un medio para incrementar la resolucion de las iamgenes pulmonares obtenidas mediante tomografia computarizada espiral

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Santos, J. M.; Torres del rio, S.; Blanco, A.; Rodriguez, R.; Parlorio, E.; Garcia, A.; Girela, E.; Hernandez, M. D. [Hospital Universitario J. M. Morales Mesequer. Murcia (Spain); Canteras, M. [Universidad de Murcia (Spain)

    2002-07-01

    The purpose of this study was to demonstrate that the use of a high-grade interpolator in the reconstruction of images of the chest increases the resolution, independently of the high-resolution filter. Eight independent observers in two groups (experts and non experts) assessed (two readings separated by a time interval) the same section of the chest reconstructed four times (st-st, st-xs, b-st, b-xs), combining standard (st) and high-resolution (b) filters and standard (st) and high-grade (xs) interpolators. The images were classified from greater to lesser in terms of the resolution perceived. The results were used to compare the degree of resolution introduced by the interpolator and the filter and to determine whether or not there existed variability between observers and between the observations of each, and whether experience played a role in the findings. Six of the eight observers assigned the b-xs images the highest degree of resolution in the majority of cases, followed by the b-st image, the st-xs image and, finally, the st-st image. The other tow observers (one expert and one nonexpert) different only with respect to the order of the st-xs and b-st images, which they assigned the second and third places, respectively. The expert group showed no intra observer variability, while two of the nonexpert observers did. The high-grade interpolator enhances the resolution of images of the chest regardless of who evaluates them, while it does not substantially increase image noise. Thus, its use is recommended in helical computed tomography imaging of the lung. (Author) 10 refs.

  13. Axial static mixer

    Science.gov (United States)

    Sandrock, H.E.

    1982-05-06

    Static axial mixing apparatus includes a plurality of channels, forming flow paths of different dimensions. The axial mixer includes a flow adjusting device for adjustable selective control of flow resistance of various flow paths in order to provide substantially identical flows through the various channels, thereby reducing nonuniform coating of interior surfaces of the channels. The flow adjusting device may include diaphragm valves, and may further include a pressure regulating system therefor.

  14. Determinación del color en epicarpios de mango (Mangifera sp.) y plátano (Musa AAB) en maduración mediante sistema de visión computarizada

    OpenAIRE

    Carlos Alberto Padrón Pereira; Gisel Marié Padrón León

    2012-01-01

    En investigación agraria y alimentaria, el procesamiento y análisis de imágenes en color se ha convertido en un área importante de estudio. En este contexto, el sistema de visión computarizada ha demostrado ser un procedimiento útil. Los propósitos de este trabajo fueron determinar el color en epicarpios de frutos de mango y plátano durante la maduración con sistema de visión computarizada. El sistema lo constituyó un escenario iluminado, una cámara digital CCD y un computador (desktop), ambo...

  15. Hallazgos radiográficos de connotación endodóntica utilizando tomografía computarizada de haz cónico

    OpenAIRE

    H. Monardes Cortés; J. Abarca Reveco; D. Chaparro González; F. Pizarro Gamboa

    2015-01-01

    En la práctica de la odontología, la tomografía computarizada de haz cónico (TCHC) ha sido utilizada en la indicación de implantes y cirugía maxilofacial. En endodoncia, ya ha comenzado su uso, por la posibilidad de conocer las tres dimensiones del diente. Este estudio busca determinar la frecuencia de las diferentes condiciones patológicas más prevalentes en endodoncia, mediante el uso de TCHC, para lo cual se identificaron y cuantificaron hallazgos radiográficos de connotación endodóntica e...

  16. Axial tomographic scanner

    International Nuclear Information System (INIS)

    1976-01-01

    An axial tomographic system is described comprising axial tomographic means for collecting sets of data corresponding to the transmission or absorption of a number of beams of penetrating radiation through a planar slice of an object. It includes means to locate an object to be analyzed, a source and detector for directing one or more beams of penetrating radiation through the object from the source to the detector, and means to rotate (and optionally translate) the source as well as means to process the collected sets of data. Data collection, data processing, and data display can each be conducted independently of each other. An additional advantage of the system described is that the raw data (i.e., the originally collected data) are not destroyed by the data processing but instead are retained intact for further reference or use, if needed

  17. Importância da tomografia de córnea para o diagnóstico de ectasia

    Directory of Open Access Journals (Sweden)

    Bruno de Freitas Valbon

    2012-10-01

    Full Text Available OBJETIVO: Utilização da metodologia para interpretação da tomografia de córnea e segmento anterior para a detecção e diagnóstico de ectasia corneana. MÉTODOS: Descrição da interpretação clínica dos índices da tomografia de córnea e segmento anterior (Pentacam High Resolution - Oculus, Wetzlar,Germany; relato de 3 casos, demonstrando a importância da propedêutica no exame complementar, através do Pentacam HR®. CONCLUSÃO: Nossa experiência compatibiliza-se com os relatos de literatura na demonstração do incremento de sensibilidade e especificidade para a detecção precoce de susceptibilidade e diagnóstico de ectasia corneana, utilizando a tomografia de córnea e segmento anterior.

  18. Paracoccidioidomicose pulmonar: aspectos na tomografia computadorizada de alta resolução High-resolution computed tomography findings in pulmonary paracoccidioidomycosis

    Directory of Open Access Journals (Sweden)

    Maria Angélica Soares Muniz

    2002-06-01

    Full Text Available O comprometimento pulmonar na paracoccidioidomicose é muito freqüente, podendo até ser a única manifestação da doença. Neste trabalho são analisados os aspectos encontrados nas tomografias computadorizadas de alta resolução do tórax de 30 pacientes com paracoccidioidomicose confirmada. Por meio desta análise foram determinados os achados mais comuns e suas formas de apresentação e distribuição nos pulmões. Os aspectos mais freqüentemente observados foram: espessamento esparso de septos interlobulares (96,7%, opacidades em vidro fosco (66,7%, nódulos (60%, aumento irregular do espaço aéreo (enfisema paracicatricial (56,7%, espessamento de paredes brônquicas (46,7%, espessamento pleural (36,7%, cavidades (36,7%, dilatação da traquéia (33,3%, distorção arquitetural (30%, consolidação do espaço aéreo (30%, bandas parenquimatosas (23,3%, reticulado intralobular (13,3% e espessamento irregular do interstício axial peri-hilar (10%. A radiografia do tórax apresenta limitada capacidade de avaliar doenças pulmonares difusas, tornando a tomografia computadorizada de alta resolução do tórax essencial para avaliação dos pacientes com paracoccidioidomicose pulmonar.Pulmonary disease in paracoccidioidomycosis is very common and in some cases can be the sole manifestation of the disease. We studied the findings observed in 30 patients with pulmonary paracoccidioidomycosis submitted to high-resolution computed tomography in order to determine the most frequent findings, presentation patterns and distribution of paracoccidioidomycosis lesions in the lungs. The most frequent findings observed on high-resolution computed tomography were: interlobular septal thickening (96.7%, ground-glass opacities (66.7%, nodules (60%, irregular air-space enlargement (56.7%, bronchial wall thickening (46.7%, pleural thickening (36.7%, cavitation (36.7%, tracheal dilatation (33.3%, architectural distortion (30%, air-space consolidation (30

  19. Compton backscattering axial spectrometer

    International Nuclear Information System (INIS)

    Rad'ko, V.E.; Mokrushin, A.D.; Razumovskaya, I.V.

    1981-01-01

    Compton gamma backscattering axial spectrometer of new design with the 200 time larger aperture as compared with the known spectrometers at the equal angular resolution (at E=159 keV) is described. Collimator unit, radiation source and gamma detector are located in the central part of the spectrometer. The investigated specimen (of cylindrical form) and the so called ''black body'' used for absorption of photons, passed through the specimen are placed in the peripheric part. Both these parts have an imaginary symmetry axis that is why the spectrometer is called axial. 57 Co is used as the gamma source. The 122 keV spectral line which corresponds to the 83 keV backscattered photon serves as working line. Germanium disk detector of 10 mm diameter and 4 mm height has energy resolution not worse than 900 eV. The analysis of results of test measurements of compton water profile and their comparison with data obtained earlier show that only finity of detector resolution can essentially affect the form of Compton profile. It is concluded that the suggested variant of the spectrometer would be useful for determination of Compton profiles of chemical compounds of heavy elements [ru

  20. Axial skeletal CT densitometry

    International Nuclear Information System (INIS)

    Lampmann, L.E.H.

    1982-01-01

    Since the discovery of the Roentgen ray a precise and accurate assessment of bone mineral content has been a challenge to many investigators. A number of methods have been developed but no one satisfied. Considering its technical possibilities computed tomography is very promising in determination of bone mineral content (BMC). The new modality enables BMC estimations in the axial skeletal trabecular bone. CT densitometry can be performed on a normal commercially available third generation whole body CT scanner. No dedicated device in a special clinical set-up is necessary. In this study 106 patients, most of them clinically suspected of osteoporosis, were examined. The new method CT densitometry has been evaluated. The results have been correlated to alternative BMC determination methods. (Auth.)

  1. Mudanças na estrutura do solo avaliada com uso de tomografia computadorizada.

    OpenAIRE

    PIRES, L. F.; BACCHI, O. O. S.

    2010-01-01

    O objetivo deste trabalho foi avaliar, em escala milimétrica, a modificação da densidade e da porosidade de amostras deformadas de solo submetidas a ciclos de umedecimento e secamento (U-S), por meio da tomografia computadorizada de raios gama. Amostras com 98,1 cm³ foram preparadas procedendo ao peneiramento do solo em malha de 2 mm e acondicionamento de forma homogênea em tubos de PVC. As amostras de solo foram submetidas a um, dois e três ciclos de U-S. As amostras controle não foram subme...

  2. Linfangiectasia renal: achado incidental em tomografia computadorizada multicorte e revisão da literatura

    Directory of Open Access Journals (Sweden)

    Rodrigo Abdalla de Vasconcelos

    2012-06-01

    Full Text Available Linfangiectasia renal é uma condição rara, caracterizada por coleções parapiélicas e perirrenais, que pode progredir de assintomática para insuficiência renal crônica. É apresentado um caso de achado incidental em tomografia computadorizada de linfangiectasia renal bilateral em paciente assintomático, com descrição dos principais achados à luz dos métodos de imagem e ampla revisão da literatura.

  3. DETERMINACIÓN DEL COLOR EN EPICARPIO DE TOMATES (LYCOPERSICUM ESCULENTUM MILL. CON SISTEMA DE VISIÓN COMPUTARIZADA DURANTE LA MADURACIÓN

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Padrón Pereira

    2012-01-01

    Full Text Available Se estudió la evolución del color de muestras de tomates durante la maduración a temperatura ambiente y otras en refrigeración, mediante Sistema de Visión Computarizada (SVC. El SVC lo constituye un escenario iluminado, una cámara digital CCD y un computador (Laptop ambos calibrados. El procesamiento digital de las imágenes se llevó a cabo con el software Adobe® Photoshop® CS3 Extended, con los cuales generaron imágenes promediadas en coordenadas L*, a* y b*. La relación a*/b* y las coordenadas polares c* y hº, que presentaron diferencias estadísticas significativas entre las muestras determinadas (p<0,05.

  4. Estudio mediante tomografía computarizada de los criterios radiográficos aplicados al diagnóstico del síndrome navicular del caballo

    OpenAIRE

    Arias Sanz, Pablo

    2016-01-01

    El síndrome del navicular ha sido reconocido como una de las causas más importantes de claudicación en el caballo. En la radiografía, muchas de las lesiones del hueso navicular quedan mal definidas. Y entre ellas la pérdida de definición córtico-medular. La TC es la mejor modalidad de imagen para la valoración de las características del hueso. Pero además de la información morfológica, también proporciona información sobre la atenuación radiológica de los tejidos (tomografía computarizada cua...

  5. Detección de ganglios linfáticos en imágenes de tomografía computarizada

    OpenAIRE

    Román Andújar, Laura

    2016-01-01

    La detección y medición de los ganglios linfáticos juega un papel muy importante tanto en el tratamiento como en el diagnóstico del cáncer. Actualmente en las rutinas clínicas este trabajo de evaluación se realiza manualmente corte a corte, asignando a cada uno de los ganglios si presentan o no un cuadro clínico y patológico de extensión de la enfermedad. Este trabajo se basa en la tarea de detectar y obtener las medidas de ganglios linfáticos en imágenes de tomografía computarizada en el med...

  6. O valor da tomografia computadorizada helicoidal sem contraste na avaliação de pacientes com dor no flanco

    Directory of Open Access Journals (Sweden)

    Galvão Filho Mário de Melo

    2001-01-01

    Full Text Available Os nossos objetivos foram estabelecer a eficácia da tomografia computadorizada sem contraste em diagnosticar a ureterolitíase, calcular a freqüência dos principais sinais tomográficos e medir a concordância interobservador, comparando-a com os resultados obtidos na urografia excretora, realizando estudo prospectivo duplo-cego em 25 pacientes com cólica nefrética. Em ambos os procedimentos avaliamos a existência de aumento renal, hidronefrose e cálculo ureteral. Deste último, descrevemos a sua localização e dimensão. Nos exames de tomografia computadorizada sem contraste procuramos também por estrias perirrenais, edema periureteral e o sinal do halo. Em 23 dos 25 exames de tomografia computadorizada sem contraste (92% e em 17 das 25 urografias excretoras (68% houve concordância dos resultados entre os dois observadores. Em 21 dos 25 pacientes os resultados dos dois métodos foram concordantes. Concluímos que a tomografia computadorizada sem contraste apresenta eficácia superponível à urografia excretora na avaliação de pacientes com cólica nefrética, sendo um método reprodutível e sem promover o desconforto do uso do contraste endovenoso.

  7. Avaliação de seis anos de fraturas cervicais subaxiais Evaluación de seis años de fracturas cervicales subaxiales Evaluation of six years of cervical sub-axial fractures

    Directory of Open Access Journals (Sweden)

    Leonardo Franco Pinheiro Gaia

    2013-01-01

    ón (AO. Se utilizaron radiografías en las incidencias frontal y lateral y tomografía computarizada, para dividir las fracturas en A (compresión, B (distracción y C (rotación, de acuerdo con el patrón de presentación. Se analizaron los siguientes parámetros: sexo, edad, clasificación AO, mecanismo de trauma, presencia de déficit neurológico y tratamiento quirúrgico o conservador. RESULTADOS: Fueron analizadas 264 historias clínicas, siendo 216 pacientes hombres e 48 mujeres. La media de edad de éstos pacientes fue de 38,55 años. El mecanismo de trauma más común de las fracturas cervicales subaxiales fue el accidente automovilístico, con 84 casos. En cuanto al tipo de fractura según la clasificación AO, la más frecuente fue el tipo B. De los casos evaluados, 136 pacientes presentaron déficit neurológico parcial o completo. El tratamiento quirúrgico fue realizado en 166 casos. CONCLUSIÓN: Queda claro que las fracturas cervicales representan un importante problema para la salud pública y privada en Brasil. La prevención de fracturas cervicales presenta la mejor relación costo beneficio en el abordaje de éstas lesiones.OBJECTIVE: Retrospectively assess the factors related to cervical trauma, according to the type of fracture based on the AO classification, taking into account etiological and epidemiological aspects of the event. METHODS: Records of patients with cervical fractures were retrospectively reviewed, from 2004 to 2009. The sub-axial fractures (C3-C7 were studied because they fit into only one classification (AO. Frontal and lateral x-rays were used as well as CTs to divide the fractures into A (compression, B (distraction and C (rotation, in accordance with the presented pattern. The following parameters were assessed: gender, age, AO classification, trauma mechanism, presence of neurological deficit, and conservative or surgical treatment. RESULTS: The study included 264 records from the spine, where 216 patients were male and 48

  8. Apendicite epiplóica: aspectos na ultra-sonografia e na tomografia computadorizada

    Directory of Open Access Journals (Sweden)

    Melo Alessandro Severo Alves de

    2002-01-01

    Full Text Available A apendicite epiplóica é uma condição inflamatória incomum, porém cada vez mais freqüentemente diagnosticada pelos métodos de imagem atuais (tomografia computadorizada e ultra-sonografia, os quais possibilitam a adoção de conduta terapêutica não-invasiva e eficiente. Os autores estudaram seis casos de apendicite epiplóica por meio de tomografia computadorizada, que mostraram lesões ovaladas de 1 a 2 cm de diâmetro, de localização paracólica, com atenuação de gordura e pequena lâmina hiperdensa periférica com gordura marginal peritoneal espessada. Dois desses pacientes foram submetidos a ultra-sonografia, que demonstrou formações expansivas hiperecóicas, de aspecto ovóide, não compressíveis, localizadas sob o sítio de maior sensibilidade do abdome.

  9. Dissipative Axial Inflation

    CERN Document Server

    Notari, Alessio

    2016-12-22

    We analyze in detail the background cosmological evolution of a scalar field coupled to a massless abelian gauge field through an axial term $\\frac{\\phi}{f_\\gamma} F \\tilde{F}$, such as in the case of an axion. Gauge fields in this case are known to experience tachyonic growth and therefore can backreact on the background as an effective dissipation into radiation energy density $\\rho_R$, which which can lead to inflation without the need of a flat potential. We analyze the system, for momenta $k$ smaller than the cutoff $f_\\gamma$, including numerically the backreaction. We consider the evolution from a given static initial condition and explicitly show that, if $f_\\gamma$ is smaller than the field excursion $\\phi_0$ by about a factor of at least ${\\cal O} (20)$, there is a friction effect which turns on before that the field can fall down and which can then lead to a very long stage of inflation with a generic potential. In addition we find superimposed oscillations, which would get imprinted on any kind of...

  10. Determinación del color en epicarpios de mango (Mangifera sp. y plátano (Musa AAB en maduración mediante sistema de visión computarizada

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Padrón Pereira

    2012-01-01

    Full Text Available En investigación agraria y alimentaria, el procesamiento y análisis de imágenes en color se ha convertido en un área importante de estudio. En este contexto, el sistema de visión computarizada ha demostrado ser un procedimiento útil. Los propósitos de este trabajo fueron determinar el color en epicarpios de frutos de mango y plátano durante la maduración con sistema de visión computarizada. El sistema lo constituyó un escenario iluminado, una cámara digital CCD y un computador (desktop, ambos calibrados. El procesamiento digital de las imágenes se llevó a cabo con el software Adobe® Photoshop®, con el cual se generaron imágenes promediadas en coordenadas rectangulares L*, a*, b*. Las coordenadas polares (C*, hº fueron calculadas, y para todos los casos, los resultados fueron descritos. Los resultados permitieron describir adecuadamente las variaciones de color en epicarpios de ambos frutos durante la maduración, mediante coordenadas colorimétricas de los espacios de color CIE-L*a*b* y CIE-L*C*hº, a través de imágenes digitales obtenidas con sistema de visión computarizada.

  11. Determinación del color en epicarpios de mango (Mangifera sp. y plátano (Musa AAB en maduración mediante sistema de visión computarizada

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Padrón Pereira

    2012-12-01

    Full Text Available En investigación agraria y alimentaria, el procesamiento y análisis de imágenes en color se ha convertido en un área importante de estudio. En este contexto, el sistema de visión computarizada ha demostrado ser un procedimiento útil. Los propósitos de este trabajo fueron determinar el color en epicarpios de frutos de mango y plátano durante la maduración con sistema de visión computarizada. El sistema lo constituyó un escenario iluminado, una cámara digital CCD y un computador (desktop, ambos calibrados. El procesamiento digital de las imágenes se llevó a cabo con el software Adobe® Photoshop®, con el cual se generaron imágenes promediadas en coordenadas rectangulares L*, a*, b*. Las coordenadas polares (C*, hº fueron calculadas, y para todos los casos, los resultados fueron descritos. Los resultados permitieron describir adecuadamente las variaciones de color en epicarpios de ambos frutos durante la maduración, mediante coordenadas colorimétricas de los espacios de color CIE-L*a*b* y CIE-L*C*hº, a través de imágenes digitales obtenidas con sistema de visión computarizada.

  12. Characterization of Multiflux Axial Compressors

    International Nuclear Information System (INIS)

    Brasnarof, Daniel; Kyung Kyu-Hyung; Rivarola, Martin; Gonzalez Jose; Florido, Pablo; Orellano, Pablo; Bergallo, Juan

    2003-01-01

    In the present work the results of analytical models of performance are compared with experimental data acquired in the multi flux axial compressor test facility, built in The Pilcaniyeu Technological Complex for the SIGMA project.We describe the experimental circuit and the data of the dispersion inside the axial compressor obtained using a tracer gas through one of the annular inlets.The attained results can be used to validate the design code for the multi flux axial compressors and SIGMA industrial plant

  13. Fluorescence axial nanotomography with plasmonics.

    Science.gov (United States)

    Cade, Nicholas I; Fruhwirth, Gilbert O; Krasavin, Alexey V; Ng, Tony; Richards, David

    2015-01-01

    We present a novel imaging technique with super-resolution axial sensitivity, exploiting the changes in fluorescence lifetime above a plasmonic substrate. Using conventional confocal fluorescence lifetime imaging, we show that it is possible to deliver down to 6 nm axial position sensitivity of fluorophores in whole biological cell imaging. We employ this technique to map the topography of the cellular membrane, and demonstrate its application in an investigation of receptor-mediated endocytosis in carcinoma cells.

  14. Precisión diagnóstica de la angiografía coronaria por tomografía computarizada multislice aplicada al “mundo real”

    Directory of Open Access Journals (Sweden)

    Claudio Llauradó

    2006-01-01

    Full Text Available Objetivo Evaluar la precisión diagnóstica de la angiografía coronaria por tomografía computarizada multislice (ACTCM para la detección de estenosis significativas en arterias coronarias. Material y métodos Se estudiaron pacientes con indicación de cinecoronariografía diagnóstica sin antecedents de alergia al contraste, insuficiencia renal ni arritmias. Para la adquisición de imágenes se utilizó un tomógrafo multislice (multicorte ( Brilliance 40, Philips, The Netherlands gatillado electrocardiográficamente. Se administraron 90-125 ml de contraste yodado por vía endovenosa. La obesidad, la diabetes, los segmentos difusamente calcificados, con diámetro < 2,0 mm, y aquellos tratados con stents no constituyeron criterios de exclusión. Las lesiones se definieron significativas cuando presentaron una reducción luminal = 50% por ACTCM y angiografía cuantitativa coronaria (QCA. Resultados Previo a la intervención se escanearon 38 pacientes. De ellos, uno (3% fue excluido debido a calidad de imagen insuficiente. Los 37 restantes (444 segmentos, con calidad de scan satisfactoria, se incluyeron en el estudio (81% hombres, edad media 62,43 ± 12,5 años, 13,5% diabéticos. El tiempo medio de scan fue de 15,12 ± 2,6 segundos. Se analizaron 444 segmentos por ambas técnicas. Se encontraron 88 (17% y 93 (18% lesiones significativas por CCG y ACTCM, respectivamente. La sensibilidad, la especificidad, el valor predictivo positivo y el valor predictivo negativo de la ACTCM para detectar estenosis significativas fueron del 82%, 93%, 72% y 96%, respectivamente. Conclusión En pacientes seleccionados para cinecoronariografía, la angiografía coronaria por tomografía computarizada multislice presenta un alto valor predictivo negativo para la detección de enfermedad obstructiva coronaria.

  15. Evaluación de la disponibilidad, utilización y costos de la tomografía computarizada en el estado de Morelos, México

    Directory of Open Access Journals (Sweden)

    Pérez-Rodríguez John

    2002-01-01

    Full Text Available Objetivo. Evaluar la disponibilidad, utilización y costos económicos de la tomografía computarizada (TC en hospitales públicos y privados en el estado de Morelos, México. Material y métodos. Mediante un estudio transversal efectuado entre enero y abril de 1999, se evaluaron cuatro hospitales en el estado de Morelos, dos públicos y dos privados. Se llevaron a cabo entrevistas individuales con los directores, administradores, médicos radiólogos y jefes de mantenimiento. Se realizó un análisis estadístico descriptivo de las variables, disponibilidad, utilización y costos, así como una evaluación integral de la tomografía, haciendo énfasis en la variabilidad de los patrones observados en los hospitales participantes en el estudio. Resultados. La TC es una tecnología utilizada en los hospitales del estado de Morelos desde hace más de 10 años. Aun cuando existen programas de mantenimiento preventivo y correctivo a los equipos de tomografía, sus costos son muy elevados. Además se carece de estrategias que permitan evaluar la tecnología antes de su adquisición y durante su utilización. El estudio no incluyó aspectos relativos a la correcta indicación clínica de la TC, ni a sus posibles efectos secundarios. Conclusiones. Los hallazgos obtenidos a partir de la presente investigación fueron los siguientes: a existe una carencia de procesos de evaluación y gestión tecnológica, que permita a las unidades hospitalarias un manejo eficiente de la tomografía computarizada, y b también se carece de mecanismos para regular la adquisición, evaluar la tecnología y seleccionar las mejores alternativas en función de su efectividad, eficacia, seguridad y accesibilidad.

  16. Tomografia computadorizada do cranio no diagnostico dos meningiomas: registro de 16 casos

    Directory of Open Access Journals (Sweden)

    James Pitagoras de Mattos

    1983-03-01

    Full Text Available Os autores se referem à importância do emprego da tomografia computadorizada do crânio para o preciso diagnóstico dos meningiomas. Constam da experiência 16 casos, comprovados cirúrgica e histologicamente. A média de idade foi de 52,1 anos, sendo 10 pacientes do sexo feminino e 6 do masculino. Quanto à localização, 5 eram da cavidade orbitrária e/ou asa do esfenóide, 3 parasagitais, 3 da foice, 2 supra-selares, 2 de convexidade e 1 do tentório. Concluem tratar-se de exame de grande positividade (95-98%, praticamente inócuo e que permite, na atualidade, o diagnóstico precoce conduzindo, consequentemente, a melhores resultados terapêuticos.

  17. A tomografia computadorizada na avaliação do comprometimento abdominal na paracoccidioidomicose

    Directory of Open Access Journals (Sweden)

    Roberto Martinez

    1988-06-01

    Full Text Available A tomografia computadorizada foi utilizada para avaliar o comprometimento abdominal em 25 doentes deparacoccidioidomicose. Existiam lesões intra-abdominais em, respectivamente, 75%e23% dos doentes com asformas aguda ("juvenil" e crônica ( do adulto '. A alteração mais freqüente foi o aumento dos gânglios linfáticos abdominais (12/25 casos; outras lesões foram: calcificação de gânglios linfáticos em 4 casos; obstrução das vias biliares em 5 doentes ictéricos; abscessos ou calcificação esplénica em 3 casos; 2 doentes mostraram lesões incomuns: aumento e irrgularidade do pâncreas em um e múltiplos abscessos nos músculos psoas em outro. Conclui-se que a tomografia computadorizada é procedimento útil na avaliação da disseminação da paracoccidioidomicose ao abdome e no diagnóstico de suas complicações abdominais.Computerised tomography was utilized in 25 paracoccidioidomycosis patients to evaluate abdominal involvement. This was observed in patients, 75% of acute (juvenile type and 23% of chronic (adult type patients. The most frequent alteration was abdominal lymphnode enlargement (12/25 cases. Other lesions consisted of lymphnode calcification in 4 cases, biliary tract obstruction in 5 icteric patients, splenic abscess or calcification in 3 cases. Two patients had unusual lesions: one with pancreatic enlargement and irregularity and other with multiple abscesses in both psoas muscles. It was concluded that computerised tomography is a useful procedure for evaluating paracoccidioidomycosis dissemination to the abdomen and for the diagnosis of its abdominal complications.

  18. Diagnóstico diferencial de lesiones cerebrales con realce en anillo en tomografía computarizada y resonancia magnética

    Directory of Open Access Journals (Sweden)

    Vicente de Jesús Aljure

    2016-07-01

    Full Text Available La tomografía computarizada y la resonancia magnética nuclear son técnicas imagenológicas de diagnóstico médico que ofrecen información excelente de diferentes procesos infecciosos, traumáticos o tumorales de cualquier parte del cuerpo humano. Con ellos se permitió la identificación de innumerables patologías y patrones característicos de las mismas, siendo una de ellas, el realce en anillo en el Sistema Nervioso Central. Numerosas patologías presentan este patrón imagenológico: Glioblastoma multiforme, síndromes desmielinizantes, metástasis, abscesos cerebrales, toxoplasmosis cerebral, neurocisticercosis, linfomas, entre otros. El objetivo del presente artículo es brindar una revisión general de las patologías más frecuentes en los servicios de imagenología, permitiendo su correlación con las características clínicas y brindando una ayuda al clínico que para establecer un diagnóstico adecuado.

  19. Carcinoma de células transicionais do trato urinário: aspectos da tomografia computadorizada

    Directory of Open Access Journals (Sweden)

    Almeida Junior José Guiomar de

    2003-01-01

    Full Text Available Embora relativamente incomum, o carcinoma de células transicionais do trato urinário é o segundo tumor mais freqüente do rim. Neste trabalho foram analisadas, de forma retrospectiva, as tomografias computadorizadas de dez pacientes com carcinoma de células transicionais confirmado por exame histopatológico. A bexiga foi acometida em 60% dos casos, o sistema pielocalicinal em 60% e o ureter em 10% deles. Lesões sincrônicas estiveram presentes em 40% das vezes. Os aspectos encontrados foram lesões vegetantes, espessamento da parede do ureter e lesões infiltrativas do rim. Foram descritos dois casos de tumores calcificados e um carcinoma de células transicionais surgindo no interior de um divertículo de bexiga. A tomografia computadorizada detectou extensão local do tumor em 80% dos pacientes e lesão a distância em 20%. A tomografia computadorizada permitiu caracterizar a extensão da doença, localmente e a distância, possibilitando que um grupo selecionado de pacientes pudesse ser tratado de forma conservadora.

  20. Axial structure of the nucleon

    Energy Technology Data Exchange (ETDEWEB)

    Veronique Bernard; Latifa Elouadrhiri; Ulf-G Meissner

    2002-01-01

    We review the current status of experimental and theoretical understanding of the axial nucleon structure at low and moderate energies. Topics considered include (quasi)elastic (anti)neutrino-nucleon scattering, charged pion electroproduction off nucleons and ordinary as well as radiative muon capture on the proton.

  1. Axial stability of Taylor bubbles

    NARCIS (Netherlands)

    Lu, X.; Prosperetti, Andrea

    2006-01-01

    Long gas bubbles rising in a vertical tube are observed to lose axial symmetry and become unstable in a downward liquid flow. In this paper an approximate linear stability analysis of this phenomenon is presented. It is found that, under the combined effect of gravity and the pressure gradient which

  2. Aplicación de metodología de modelado 3D utilizando Tomografías Computarizadas para su análisis numérico

    OpenAIRE

    Ariel Fuerte Hernández; Ricardo Gustavo Rodríguez Cañizo; Orlando Susarrey Huerta; Emmanuel Alejandro Merchán Cruz; Juan Manuel Sandoval Pineda; Elizabeth Pérez Hernández

    2014-01-01

    Este trabajo presenta una metodología para la generación de un modelo del segmento lumbar porcino y humano L4-L5 a partir de Tomografías Computarizadas (TC). El uso de la TC como herramienta de biomodelado es una técnica que actualmente es muy usada en el desarrollo de análisis numéricos computacionales mediante programas de Análisis de Elemento Finito (AEF), lo que permite visualizar y analizar estructuras anatómicas simples y/o complejas. Por lo que, la relevancia de este trabajo radica en ...

  3. La tomografía computarizada en cardiopatía isquémica: de la calcificación coronaria a la caracterización tisular miocárdica

    OpenAIRE

    Jordi Estornell Erill

    2015-01-01

    Durante las últimas 2 décadas las técnicas de imagen han alcanzado un papel indispensable en prácticamente todas las enfermedades cardiovasculares. La tomografía computarizada cardiaca, en el campo de la cardiopatía isquémica, proporciona información irreemplazable para la investigación clínica y básica, y se ha convertido también en imprescindible para guiar la actitud terapéutica de los pacientes con enfermedad coronaria en la práctica diaria. Revisamos su estado actual desde la mirada de s...

  4. Estudio comparativo cefalométrico de imágenes bidimensionales y volumétricas obtenidas con tomografía computarizada de haz cónico

    OpenAIRE

    Míguez Contreras, Manuel

    2017-01-01

    Antecedentes: La tomografía computarizada de haz cónico (CBCT) es una valiosa técnica de estudio radiográfico y su aplicación en la clínica dental ofrece amplias posibilidades, entre ellas la obtención de imágenes para el trazado cefalométrico clásico rutinario bidimensional (2D) frontal o lateral, o la posibilidad de avanzar y realizar trazados tridimensionales (3D) para el diagnóstico del paciente ortodóncico. Se ha descrito que en el momento de realizar los trazados pueden e...

  5. Perfusão miocárdica dinâmica por tomografia computadorizada de dupla fonte de raio X

    Directory of Open Access Journals (Sweden)

    José Rodrigues Parga Filho

    2012-03-01

    Full Text Available Relatamos caso de perfusão dinâmica e quantitativa pela tomografia computadorizada de múltiplos detectores de dupla fonte de Raio X em um paciente de 44 anos, com diagnóstico prévio de doença coronariana. A tomografia demonstrou quantitativamente déficit de perfusão miocárdica nos territórios irrigados por artérias com estenoses significativas confirmadas pela angiotomografia e pela cineangiocoronariografia. A tomografia computadorizada com dupla fonte de Raio X permitiu a avaliação dinâmica perfusional e anatômica, em um único estudo, durante o controle evolutivo desse paciente.

  6. Axial magnetic field produced by axially and radially magnetized permanent rings

    International Nuclear Information System (INIS)

    Peng, Q.L.; McMurry, S.M.; Coey, J.M.D.

    2004-01-01

    Axial magnetic fields produced by axially and radially magnetized permanent magnet rings were studied. First, the axial magnetic field produced by a current loop is introduced, from which the axial field generated by an infinitely thin solenoid and by an infinitely thin current disk can be derived. Then the axial fields produced by axially and by radially magnetized permanent magnet rings can be obtained. An analytic formula for the axial fields produced by two axially magnetized rings is given. A permanent magnet with a high axial gradient field is fabricated, the measured results agree with the theoretical calculation very well. As an example, the axial periodic field produced by an arrangement of alternating axially and radially magnetized rings has been discussed

  7. View of the Axial Field Spectrometer

    CERN Multimedia

    1980-01-01

    The Axial Field Spectrometer, with the vertical uranium/scintillator calorimeter and the central drift chamber retracted for service. One coil of the Open Axial Field Magnet is just visible to the right.

  8. Estimativa dos valores de MSAD em procedimentos de tomografia computadorizada utilizando filmes radiocrômicos

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    Bruno Beraldo Oliveira

    2013-04-01

    Full Text Available OBJETIVO: Verificar a viabilidade de filmes radiocrômicos como um dosímetro alternativo para estimativa da dose média em cortes múltiplos a partir dos perfis de kerma. MATERIAIS E MÉTODOS: Os filmes foram distribuídos em cilindros posicionados no centro e nas regiões periféricas de um objeto simulador padrão de abdome utilizado para dosimetria em tomografia computadorizada. RESULTADOS: Os valores de dose média em cortes múltiplos calculados foram 13,6 ± 0,7, 13,5 ± 0,7 e 18,7 ± 1,0 mGy para os valores de passo (pitch de 0,75, 1,00 e 1,50, respectivamente. CONCLUSÃO: Apesar de os resultados mostrarem valores menores que o nível de referência de radiodiagnóstico de 25 mGy estabelecido pela legislação brasileira para exames de abdome, eles sugerem que há espaço para otimização dos procedimentos e uma revisão do valor para o nível de referência de radiodiagnóstico brasileiro.

  9. Técnicas de aquisição rápida em tomografia por ressonância magnética nuclear

    OpenAIRE

    Bernd Uwe Foerster

    1994-01-01

    Neste trabalho apresentamos e comparamos diferentes técnicas de tomografia bidimensional por RMN implementados num sistema de tomografia de campo magnético ultra-baixo (O.05T). A partir da seqüência convencional \\"Spin Echo\\" (SE), utilizada rotineiramente, implementamos a seqüência \\"Gradient Recalled Echo\\" (GRE) e duas seqüências que utilizam o principio de Steady-State Free Precession (SSFP), sendo \\"Fast Low Angle Shot\\" (FLASH) e \\"Fast Acquisition Double Echo\\" (FADE). Com as seqüência...

  10. Ruptura traumática do diafragma: aspectos na tomografia computadorizada Traumatic diaphragmatic rupture: computed tomography findings

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    Alessandro Severo Alves de Melo

    2002-11-01

    Full Text Available A ruptura traumática do diafragma é uma condição incomum, porém cada vez mais freqüentemente diagnosticada pela tomografia computadorizada, especialmente pela técnica helicoidal associada às reconstruções multiplanares, possibilitando a adoção de conduta terapêutica cirúrgica rápida e eficiente. Os autores estudaram seis pacientes com ruptura traumática do diafragma submetidos a tomografia computadorizada, que demonstrou herniação de estruturas abdominais para o interior do tórax através de área de ruptura na hemicúpula frênica esquerda em quatro casos; os outros dois pacientes foram submetidos a procedimento cirúrgico por trauma abdominal associado, que demonstrou lesões diafragmáticas, sem evidência de herniação na tomografia computadorizada.Traumatic diaphragmatic rupture is an uncommon condition that has been diagnosed more frequently with the aid of computed tomography, particularly when using helical technique in association with multiplanar reconstructions. This technique allows adoption of an efficient and quick surgical therapeutic approach. The authors studied six patients with traumatic diaphragmatic rupture that were submitted to computed tomography. In four of the patients there was herniation of intraabdominal viscera through a site of rupture in the left diaphragm. The two other patients underwent surgery due to abdominal injuries, which revealed diaphragmatic lesions but no herniation of intraabdominal viscera.

  11. Prognosis of the computerized tomography in the severe head injury. Valor pronostico de la tomografia axial computada (TC) en los traumatismos craneoencefalicos severos

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Nieto, J.J.; Lorenzo Dominguez, M.T.; Martin Sanchez, M.J.; Sanchez Gonzalez, E.

    1991-01-01

    A prospective study is made with sixty five people affected of severe head injury, that is to say, with eight or less points in the Glasgow Coma Scale (GCS), when they get to the hospital. They are studied by computerized tomography at admission, and three and seven days after arrival. In this way, we appraise the type of the lesion, its intensity and the possible prognosis, considering in the last case three features: a) ventricular collapse; b) the mean line structure s shift; and c) effects on perimesencephalic cistern. The findings were parametized and we were able to introduce into the computer program relationships between these findings and the end results. These last ones were appraised through the Glasgow Outcome Scale (GOS). We could show that certain findings in computerized tomography scans have an unavoidable prognosis while as others have a more favorable prognosis. (Author)

  12. Estudo do manto superior sob o Brasil Central utilizando tomografia sísmica de tempo de percurso

    OpenAIRE

    Azevedo, Paulo Araújo de

    2013-01-01

    Neste trabalho, apresentamos os resultados de tomografia sísmica de tempo de percurso utilizando ondas P no Brasil Central. Foram realizadas inversões para dados registrados durante os anos de 2008-2012 por 15 estações distribuídas na área de estudo. Além disso, esses dados foram incluídos no banco de dados utilizado por Rocha et al. (2011), a fim de melhorar a resolução das anomalias em algumas regiões dentro da área de estudo. O objetivo foi estudar o manto superior sob o Brasil Central, pr...

  13. Malária pulmonar: aspectos na tomografia computadorizada de alta resolução - relato de caso

    Directory of Open Access Journals (Sweden)

    Rodrigues Rosana

    2004-01-01

    Full Text Available Neste trabalho é relatado o caso de paciente do sexo masculino, de 38 anos de idade, que desenvolveu quadro de malária com comprometimento pulmonar. A tomografia computadorizada de alta resolução evidenciou espessamento de septos interlobulares e de bainhas peribroncovasculares, com áreas esparsas de atenuação em vidro fosco e de consolidações, além de derrame pleural bilateral, aspectos compatíveis com edema pulmonar. O paciente recebeu tratamento específico, evoluindo bem e tendo alta 11 dias após a internação.

  14. Decisión clínica para la realización de tomografía axial computarizada de cráneo en niños con traumatismo craneoencefálico no severo

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    Celine Alicia Franco-Koehrlen

    2015-05-01

    Conclusiones: En pacientes pediátricos con TCE no severo sin datos de deterioro neurológico se sugiere una valoración clínica detallada y que genere confianza en los familiares, con la finalidad de evitar la toma de TACC cuando su uso no se encuentra justificado.

  15. Axial diagnostic package for Z

    International Nuclear Information System (INIS)

    Nash, T.J.; Derzon, M.S.; Chandler, G.

    1998-06-01

    The authors have developed and fielded an axial diagnostic package for the 20 MA, 100 ns, z-pinch driver Z. The package is used to diagnose dynamic hohlraum experiments which require an axial line of sight. The heart of the package is a reentrant cone originally used to diagnose ion-beam-driven hohlraums on PBFA-H. It has one diagnostic line of sight at 0 degrees, 4 at 6 degrees, and 4 at 9 degrees. In addition it has a number of viewing, alignment, and vacuum feedthrough ports. The front of the package sits approximately 5 feet from the pinch. This allows much closer proximity to the pinch, with inherently better resolution and signal, than is presently possible in viewing the pinch from the side. Debris that is preferentially directed along the axis is mitigated by two apertures for each line of sight, and by fast valves and imaging pinholes or cross slits for each diagnostic. In the initial run with this package they fielded a time resolved pinhole camera, a five-channel pinhole-apertured x-ray diode array, a bolometer, a spatially resolved time-integrated crystal spectrometer, and a spatially and temporally resolved crystal spectrometer. They present data obtained from these diagnostics in the dynamic hohlraum research conducted on Z

  16. Trauma renal grau III com fístula urinária subestadiamento pela tomografia?

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    Bruno Abade

    2007-06-01

    Full Text Available O rim é órgão freqüentemente lesado em traumas abdominais fechados. As indicações para tratamento conservador do trauma renal fechado estão cada vez mais amplas. Uma das complicações, a coleção urinária perirrenal, pode ser tratada de forma expectante ou mesmo minimamente invasiva, como drenagem percutânea e/ou colocação de catéter ureteral (“Duplo J” endoscópica. Relatamos um caso neste contexto, no qual a tomografia computadorizada subestadiou o grau de lesão renal, não tendo identificado inicialmente a lesão de via excretora. O caso evoluiu satisfatoriamente após instituição de tratamento minimamente invasivo. Conclui-se que este subestadiamento pode ser minimizado através de cortes tomográficos mais finos e tardios (fase excretora, reduzindo, assim, a morbidade nesta comum afecção. ABSTRACT The kidney is commonly affected by blunt abdominal trauma. The indications for nonoperative treatment are expanding. One of the complications, the extravasation of urine from the excretory path, may be treated by watchful waiting or minimally invasive ways, such as percutaneus drainage and/or an endoscopic ureteral catheter (“Double J”. We report a case to exemplify this, where the computed tomography undergraduated the renal lesion, failing to initially identify the extravasation from the excretory path. The patient had a good outcome after the instiution of a minimally invasive treatment. We conclude that this undergraduation can be minimized by narrower and later (excretory phase slices on CT, diminishing the morbidity of this condition. Key-words: kidney/injuries, tomography X-ray computed.

  17. Tomografia cerebral computadorizada e esquizofrenia: revisão crítica da literatura

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    Carlos Von Krakauer Hübner

    1988-09-01

    Full Text Available Vários estudos sobre tomografia cerebral computadorizada (CT relatam alteração da estrutura cerebral em esquizofrenia. A grande variação da prevalência e da localização das anomalias pode estar relacionada à heterogenidade da amostra estudada, à escolha das medidas de CT ou ao uso de diferentes critérios diagnósticos. Apesar de alguns achados contraditórios, parece estabelecido que um subgrupo de pacientes esquizofrênicos apresenta atrofia cerebral discreta ou moderada; esse subgrupo se caracterizaria por apresentar cronicidade da doença, pior resposta ao tratamento neuroléptico e pela presença de outros sinais de disfunção cerebral difusa, como distúrbios neuropsicológicos, anormalidades no EEG e «soft signs» neurológicos. Sinais de atrofia na CT foram observados em pacientes esquizofrênicos jovens, no primeiro surto psicótico, indicando que o desenvolvimento das anomalias estruturais não é conseqüência do tratamento ou da cronicidade da doença. Nos diferentes estudos, pacientes com atrofia apresentaram menor carga genética (história familiar para a esquizofrenia e se observou com maior freqüência história de complicações na gestação, no parto e trauma craniano nos primeiros anos do desenvolvimento. Em face da possibilidade de que doentes esquizofrênicos com atrofia cerebral formem um subgrupo homogêneo quanto à clínica e à etiopatologia da doença, é importante identificar e estudar as alterações da CT e caracterizar esse subgrupo de pacientes.

  18. Tomografia Computadorizada de crânio em perícias criminais: uma grande aliada

    Directory of Open Access Journals (Sweden)

    Márcio Gleidson Ribeiro Dias

    2016-11-01

    Full Text Available O presente estudo trata-se de uma revisão descritiva da literatura sobre as principais vantagens da Tomografia Computadorizada (TC de crânio na área de Criminologia. Para a revisão literária foram utilizados artigos e dissertações recentes publicados entre 2007 e 2016, livros de imagenologia e medicina legal. A partir dos dados obtidos na revisão literária, nós realizamos uma descrição sobre a TC e sua evolução ao longo dos anos, suas vantagens e aplicações em perícias criminais. Destacamos a importância do laudo pericial, a responsabilidade do perito criminal, a fisiopatologia do trauma cranioencefálico e a sua relação com a violência urbana.Entre as vantagens da virtópsia em relação aos métodos tradicionais destacam-se a preservação do corpo, o arquivamento das imagens e a capacidade de identificação de vítimas através de imagens comparativas ante mortem e post mortem. Assim, a TC tem se tornado cada vez mais presente nas investigações criminais como uma tecnologia de baixo custo que é capaz de localizar, quantificar e evidenciar o trajeto de projéteis, auxiliando na identificação de cadáveres e causas da morte.

  19. Memoria de trabajo en niños escolarizados: efecto de intervalos de presentación y distractores en la prueba computarizada Memonum

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    Carlos Arturo Conde Cotes

    2013-06-01

    Full Text Available La presente investigación evaluó la memoria de trabajo visual a través de la prueba computarizada Memonum en niños escolarizados. Se evaluaron los efectos de tres tiempos de exposición (1, 4 y 8 segundos y de la presentación de un distractor sobre el desempeño mnemónico en la prueba Memonum en 72 niños pertenecientes a un colegio del área metropolitana de Bucaramanga, Colombia, con edades entre 8 y 11 años de los grados tercero, cuarto y quinto de primaria. Se encontró una diferencia significativa entre los tiempos de exposición en las variables número de aciertos y aciertos acumulados, demostrandoun mejor desempeño mnemónico en los participantes que presentaron la prueba en el tiempo de 8 segundos en comparación con los niños pertenecientes al grupo de 1 segundo; además, la presencia del distractor demostró una diferencia significativa en los aciertos y aciertos acumulados, considerándose como un estímulo generador de interferencia que perturba la capacidad de almacenamiento de la memoria de trabajo en niños. Adicionalmente, se halló una diferencia significativa en cuanto al uso de la estrategia de repetición mental, indicando que los participantes de los grupos de 4 y 8 segundos leasignaron mayor puntaje que los niños del grupo de 1 segundo. Un amplio tiempo de exposición de estímulos en la prueba Memonum aumenta la capacidad de retención; asimismo, el empleo de un distractor afecta en los participantes la capacidad de almacenamiento y esta, a suvez, aumenta de acuerdo a la progresión escolar, debidoal uso de las estrategias mnemónicas que los niños utilizan para garantizar el recuerdo de las series numéricas.

  20. Quando a fase de equilíbrio pode ser suprimida nos exames de tomografia computadorizada de abdome?

    Directory of Open Access Journals (Sweden)

    Priscila Silveira Salvadori

    2013-04-01

    Full Text Available OBJETIVO: Avaliar a necessidade de realização da fase de equilíbrio nos exames de tomografia computadorizada de abdome. MATERIAIS E MÉTODOS: Realizou-se estudo retrospectivo, transversal e observacional, avaliando 219 exames consecutivos de tomografia computadorizada de abdome com contraste intravenoso, realizados num período de três meses, com diversas indicações clínicas. Para cada exame foram emitidos dois pareceres, um avaliando o exame sem a fase de equilíbrio (primeira análise e o outro avaliando todas as fases em conjunto (segunda análise. Ao final de cada avaliação, foi estabelecido se houve mudança nos diagnósticos principais e secundários, entre a primeira e a segunda análise. Foi utilizada a extensão do teste exato de Fisher para avaliar a modificação dos diagnósticos principais (p 0,999. Com relação aos diagnósticos secundários, cinco exames (2,3% foram modificados. CONCLUSÃO: Para indicações clínicas como estadiamento tumoral, abdome agudo e pesquisa de coleção abdominal, a fase de equilíbrio não acrescenta contribuição diagnóstica expressiva, podendo ser suprimida dos protocolos de exame.

  1. Avaliação tomográfica dos pedículos vertebrais no tratamento cirúrgico dos pacientes com escoliose idiopática do adolescente Evaluación de tomografía computarizada de pedículos vertebrales nel tratamiento quirúrgico de escoliosis idiopática del adolescente Computed tomography scan evaluation of vertebral pedicles for surgical treatment of adolescent idiopathic scoliosis

    Directory of Open Access Journals (Sweden)

    Alceu Gomes Chueire

    2012-12-01

    Full Text Available OBJETIVO: Determinar através de cortes tomográficos e reconstrução tridimensional a incidência de mal posicionamento de parafusos em pacientes submetidos ao tratamento cirúrgico da Escoliose idiopática do adolescente. MÉTODOS: Foram analisados exames tomográficos de 8 pacientes, tratados cirurgicamente no Hospital de Base de São José do Rio Preto-SP, realizada instrumentação posterior partindo de T2 /T4 a L4/L5 totalizando 164 parafusos. RESULTADOS: 32,9% (n=54 apresentavam posicionamento com risco potencial,ou seja desvio acima de 2 milímetros, sendo 20,1% (n=33 com invasão lateral, 9,1% (n=15 com invasão medial, 3,6 %(n=6 com invasão anterior. Dos parafusos que ofereciam risco potencial a relação com aspecto da curva foi de 46% (n=25 na concavidade, 35% (n=19 na convexidade e 19% (n=10 em vértebras adjacentes a curva. CONCLUSÃO: Os limites de penetração aceitáveis, assim como os métodos de mensuração ainda não foram padronizados, a técnica "free hand' mostrou-se segura, apesar da violação dos pedículos. A tomografia computadorizada pré-operatória, auxilia no planejamento cirúrgico e na redução das complicações.OBJETIVO: Evaluar mediante tomografía computarizada tridimensional de reconstrucción, una mala posición de los tornillos de pedículo en pacientes con escoliosis idiopática del adolescente. MÉTODOS: Se analizó cortes de tomografía computarizada de 8 pacientes sometidos a tratamiento quirúrgico en el Hospital de Base de São José do Rio Preto-SP, que se llevaron a cabo la fusión vertebral posterior de T2/T4 a L4/L5, 164 tornillos se insertaron. RESULTADOS: 32,9% (n = 54 fueron mal colocados que ofrecen riesgo potencial, que se consideraba una desviación de 2 mm, 20,1% (n = 33, la invasión lateral, el 9,1% (n = 15 invasión medial, 3,6 % (n = 6 la invasión anterior. De los tornillos mal colocados el 46% (n = 25 fueron en la concavidad, el 35% (n = 19 en la convexidad y el 19% (n = 10 se

  2. Avaliação da reprodutibilidade da tomografia computadorizada no estadiamento da pancreatite aguda Reproducibility in the assessment of acute pancreatitis with computed tomography

    Directory of Open Access Journals (Sweden)

    Edison de Oliveira Freire Filho

    2007-12-01

    Full Text Available OBJETIVO: Medir a reprodutibilidade da tomografia computadorizada sem e com contraste na avaliação da gravidade da pancreatite aguda. MATERIAIS E MÉTODOS: Cinqüenta e um exames de tomografia computadorizada abdominal sem e com contraste de pacientes com pancreatite aguda foram analisados por dois radiologistas (observadores 1 e 2. Calculamos o índice morfológico pela tomografia computadorizada sem e com contraste, separadamente, e o índice de gravidade da tomografia computadorizada para pancreatite aguda. Medimos a reprodutibilidade intra- e interobservador da tomografia computadorizada através do índice kappa (kapa. RESULTADOS: Para a concordância interobservador obtivemos kapa de 0,666, 0,705, 0,648, 0,547 e 0,631 para índice morfológico sem e com contraste, presença de necrose pancreática, extensão da necrose pancreática e índice de gravidade da tomografia computadorizada, respectivamente. Para a concordância intra-observador dos observadores 1 e 2 obtivemos, respectivamente, kapa de 0,796 e 0,732 para o índice morfológico sem contraste; 0,725 e 0,802 para o índice morfológico com contraste; 0,674 e 0,849 para a presença de necrose pancreática; 0,606 e 0,770 para a extensão da necrose pancreática; e 0,801 e 0,687 para o índice de gravidade da tomografia computadorizada. CONCLUSÃO: O estadiamento da pancreatite aguda pela tomografia computadorizada por meio do índice morfológico e do índice de gravidade da tomografia computadorizada é um método bastante reprodutível. O não-uso do contraste não afeta a reprodutibilidade da tomografia computadorizada para o cálculo do índice morfológico.OBJECTIVE: To evaluate the reproducibility of unenhanced and contrast-enhanced computed tomography in the assessment of patients with acute pancreatitis. MATERIALS AND METHODS: Fifty-one unenhanced and contrast-enhanced abdominal computed tomography studies of patients with acute pancreatitis were blindly reviewed by two

  3. Electric machines with axial magnetic flux

    Science.gov (United States)

    Nuca, I.; Ambros, T.; Burduniuc, M.; Deaconu, S. I.; Turcanu, A.

    2018-01-01

    The paper contains information on the performance of axial machines compared to cylindrical ones. At the same time, various constructive schemes of synchronous electromechanical converters with permanent magnets and asynchronous with short-circuited rotor are presented. In the developed constructions, the aim is to maximize the usage of the material of the stator windings. The design elements of the axial machine magnetic system are presented. The FEMM application depicted the array of the magnetic field of an axial machine.

  4. Axial vector mass spectrum and mixing angles

    International Nuclear Information System (INIS)

    Caffarelli, R.V.; Kang, K.

    1976-01-01

    Spectral sum rules of the axial-vector current and axial-vector current-pseudoscalar field are used to study the axial-vector mass spectrum and mixing angles, as well as the decay constants and mixing angles of the pseudoscalar mesons. In general, the result is quite persuasive for the existence of the Jsup(PC) = 1 ++ multiplet in which one has a canonical D-E mixing. (Auth.)

  5. Centrifugal and axial compressor control

    CERN Document Server

    McMillan, Gregory K

    2009-01-01

    Control engineers, mechanical engineers and mechanical technicians will learn how to select the proper control systems for axial and centrifugal compressors for proper throughput and surge control, with a particular emphasis on surge control. Readers will learn to understand the importance of transmitter speed, digital controller sample time, and control valve stroking time in helping to prevent surge. Engineers and technicians will find this book to be a highly valuable guide on compressor control schemes and the importance of mitigating costly and sometimes catastrophic surge problems. It can be used as a self-tutorial guide or in the classroom with the book's helpful end-of-chapter questions and exercises and sections for keeping notes.

  6. Axial channeling of uttrarelativistic electrons

    Energy Technology Data Exchange (ETDEWEB)

    Telegin, V.I.; Khokonov, M.Kh. (Moskovskij Gosudarstvennyj Univ. (USSR). Nauchno-Issledovatel' skij Inst. Yadernoj Fiziki)

    1982-07-01

    The dynamics of motion of ultrarelativistic electrons under axial channeling conditions is investigated. The analysis is based on the solution of the kinetic equation obtained recently by Beloshitsky and Kumakhov. The particle dechanneling function is investigated as depending on the type of a crystal, particle energy and angle of entrance into the single crystal. It is found that for most of the beam the major diffusion mechanism is scattering by electrons. It is shown that an optimal depth range exists for which the fraction of channeled particles sharply increases at the expense of the quasi-channeled particles. In a number of cases the dechanneling length for crystals with high atomic numbers may be greater than that of light elements.

  7. Axial channeling of uttrarelativistic electrons

    International Nuclear Information System (INIS)

    Telegin, V.I.; Khokonov, M.Kh.

    1982-01-01

    The dynamics of motion of ultrarelativistic electrons under axial channeling conditions is investigated. The analysis is based on the solution of the kinetic equation obtained recently by Beloshitsky and Kumakhov. The particle dechanneling function is investigated as depending on the type of a crystal, particle energy and angle of entrance into the single crystal. It is found that for most of the beam the major diffusion mechanism is scattering by electrons. It is shown that an optimal depth range exists for which the fraction of channeled particles sharply increases at the expense of the quasi-channeled particles. In a number of cases the dechanneling length for crystals with high atomic numbers may be greater than that of light elements

  8. Radial and axial compression of pure electron

    International Nuclear Information System (INIS)

    Park, Y.; Soga, Y.; Mihara, Y.; Takeda, M.; Kamada, K.

    2013-01-01

    Experimental studies are carried out on compression of the density distribution of a pure electron plasma confined in a Malmberg-Penning Trap in Kanazawa University. More than six times increase of the on-axis density is observed under application of an external rotating electric field that couples to low-order Trivelpiece-Gould modes. Axial compression of the density distribution with the axial length of a factor of two is achieved by controlling the confining potential at both ends of the plasma. Substantial increase of the axial kinetic energy is observed during the axial compression. (author)

  9. Axial and Radial Oxylipin Transport.

    Science.gov (United States)

    Gasperini, Debora; Chauvin, Adeline; Acosta, Ivan F; Kurenda, Andrzej; Stolz, Stéphanie; Chételat, Aurore; Wolfender, Jean-Luc; Farmer, Edward E

    2015-11-01

    Jasmonates are oxygenated lipids (oxylipins) that control defense gene expression in response to cell damage in plants. How mobile are these potent mediators within tissues? Exploiting a series of 13-lipoxygenase (13-lox) mutants in Arabidopsis (Arabidopsis thaliana) that displays impaired jasmonic acid (JA) synthesis in specific cell types and using JA-inducible reporters, we mapped the extent of the transport of endogenous jasmonates across the plant vegetative growth phase. In seedlings, we found that jasmonate (or JA precursors) could translocate axially from wounded shoots to unwounded roots in a LOX2-dependent manner. Grafting experiments with the wild type and JA-deficient mutants confirmed shoot-to-root oxylipin transport. Next, we used rosettes to investigate radial cell-to-cell transport of jasmonates. After finding that the LOX6 protein localized to xylem contact cells was not wound inducible, we used the lox234 triple mutant to genetically isolate LOX6 as the only JA precursor-producing LOX in the plant. When a leaf of this mutant was wounded, the JA reporter gene was expressed in distal leaves. Leaf sectioning showed that JA reporter expression extended from contact cells throughout the vascular bundle and into extravascular cells, revealing a radial movement of jasmonates. Our results add a crucial element to a growing picture of how the distal wound response is regulated in rosettes, showing that both axial (shoot-to-root) and radial (cell-to-cell) transport of oxylipins plays a major role in the wound response. The strategies developed herein provide unique tools with which to identify intercellular jasmonate transport routes. © 2015 American Society of Plant Biologists. All Rights Reserved.

  10. Estudio comparativo cefalométrico de imágenes bidimensionales y volumétricas obtenidas con tomografía computarizada de haz cónico

    OpenAIRE

    Míguez Contreras, Manuel

    2013-01-01

    Tesis Doctoral leída en la Universidad Rey Juan Carlos de Madrid en 2013. Directores de la Tesis: Martín Romero Maroto y María Isabel Jiménez Trujillo Antecedentes: La tomografía computarizada de haz cónico (CBCT) es una valiosa técnica de estudio radiográfico y su aplicación en la clínica dental ofrece amplias posibilidades, entre ellas la obtención de imágenes para el trazado cefalométrico clásico rutinario bidimensional (2D) frontal o lateral, o la posibilidad de avanzar y r...

  11. La tomografía computarizada en cardiopatía isquémica: de la calcificación coronaria a la caracterización tisular miocárdica

    Directory of Open Access Journals (Sweden)

    Jordi Estornell Erill

    2015-03-01

    Full Text Available Durante las últimas 2 décadas las técnicas de imagen han alcanzado un papel indispensable en prácticamente todas las enfermedades cardiovasculares. La tomografía computarizada cardiaca, en el campo de la cardiopatía isquémica, proporciona información irreemplazable para la investigación clínica y básica, y se ha convertido también en imprescindible para guiar la actitud terapéutica de los pacientes con enfermedad coronaria en la práctica diaria. Revisamos su estado actual desde la mirada de su utilidad quirúrgica.

  12. Aplicación de la tomografía computarizada o TAC en el cálculo de los parámetros biomecánicos de la sección transversal de los huesos largos

    Directory of Open Access Journals (Sweden)

    José Manuel Arias López

    2014-01-01

    Full Text Available Se describe la manera de obtener imágenes de la sección transversal de los huesos largos que permitan aplicar los algoritmos para el cálculo de parámetros biomecánicos: los primeros momentos de áreas (AT, AC y am, los segundos momentos de inercia (Ix, Iy, Imin, Imax y el momento polar de inercia o de torsión, los cuales cuantifican la resistencia del hueso a la fractura y a la torsión. La tomografía computarizada o TAC es un método no invasivo para investigar la estructura de la sección transversal de los huesos largos que ayuda a comprender sobre los procesos de carga, resistencia y movilidad física entre individuos de sociedades desaparecidas e infiere en probables estrategias de subsistencia.

  13. Health and imaging outcomes in axial spondyloarthritis

    NARCIS (Netherlands)

    Machado, P.M.

    2016-01-01

    This thesis focuses on the assessment and monitoring of health and imaging outcomes in axial spondyloarthritis (SpA) and the relationship between these outcomes. Four major contributions to the understanding and management of axial SpA were made: 1) the improvement and facilitation of the assessment

  14. Aryabhata and Axial Rotation of Earth

    Indian Academy of Sciences (India)

    GENERAL I ARTICLE. Aryabhata and Axial Rotation of Earth. 3. A Brief History. Amartya Kumar Datta is in the Stat-Math Unit of. Indian Statistic.llnstiutte,. Kolkata. His research ... historical account of some of Aryabha~a's views on axial rotation of Earth, ..... and stress on periodic observations and updating of the parameters.

  15. Axial anomalies of Lifshitz fermions

    CERN Document Server

    Bakas, Ioannis

    2011-01-01

    We compute the axial anomaly of a Lifshitz fermion theory with anisotropic scaling z=3 which is minimally coupled to geometry in 3+1 space-time dimensions. We find that the result is identical to the relativistic case using path integral methods. An independent verification is provided by showing with spectral methods that the eta-invariant of the Dirac and Lifshitz fermion operators in three dimensions are equal. Thus, by the integrated form of the anomaly, the index of the Dirac operator still accounts for the possible breakdown of chiral symmetry in non-relativistic theories of gravity. We apply this framework to the recently constructed gravitational instanton backgrounds of Horava-Lifshitz theory and find that the index is non-zero provided that the space-time foliation admits leaves with harmonic spinors. Using Hitchin's construction of harmonic spinors on Berger spheres, we obtain explicit results for the index of the fermion operator on all such gravitational instanton backgrounds with SU(2)xU(1) isom...

  16. Evaluación de las placas coronarias por tomografía computarizada multidetector de 16 filas. Correlación con ecografía intravascular

    Directory of Open Access Journals (Sweden)

    Patricia Carrascosa

    2008-01-01

    Full Text Available IntroducciónEl 50% de las muertes de etiología cardiovascular se deben a la enfermedad arteriosclerótica. Estudios recientes demostraron que las placas ateromatosas más propensas al desarrollo de un evento coronario son las que presentan ciertas características particulares, como un centro o core lipídico y remodelación positiva, denominadas placas vulnerables. La determinación temprana de la presencia de este tipo de placas ateroscleróticas tendría un impacto clínico de suma importancia y podría ayudar a prevenir el desarrollo de un síndrome coronario agudo en el futuro.ObjetivoDeterminar la certeza diagnóstica de la angiografía coronaria por tomografía computarizada multidetector de 16 filas (16-ACTCM en la identificación, la caracterización y la cuantificación de las lesiones arterioscleróticas coronarias en comparación con la ecografía intravascular (EIV.Material y métodosSe estudiaron 45 pacientes con indicación de angiografía coronaria con 16-ACTCM y EIV.En cada segmento coronario se analizaron la carga de placa y las características de la placa aterosclerótica, que se clasificó en blanda, fibrosa y cálcica. La certeza diagnóstica de la 16-ACTCM para determinar la carga de placa y la identificación de placas coronarias se calculó con el método exacto binomial. Sobre la base de un análisis con curvas ROC se determinó el punto de corte para cada tipo de placa, así como la densidad media y la desviación estándar en unidades Hounsfield [UH]. Se evaluó además la certeza diagnóstica de la ACTCM para el diagnóstico de estenosis coronaria = 50%.ResultadosPara la detección de carga de placa, la sensibilidad fue del 96,2% y la especificidad fue del 81,9%. Para la detección de placas blandas, fibrosas y calcificadas, la sensibilidad y la especificidad fueron del 94,6% y 92,62%, del 94,9% y 98,5% y del 93,2% y 95,1%, respectivamente.Con un valor de corte de 85 UH, la 16-ACTCM diferenció correctamente el 86

  17. Detection of tumoral lesions in the posterior fossa, in brain computerized tomography scans for various conditions of acquiring a preliminary approach; Deteccion de lesiones tumorales en fosa posterior en imagenes de Tomografia Computarizada cerebral para diversas condiciones de adquisicion: un enfoque preliminar

    Energy Technology Data Exchange (ETDEWEB)

    Perez, M.; Carvalho-Filho, A. E.; Khoury, H. J.; Casas, M. C.; Andrade, M. E.; Paz, J. E.

    2010-07-01

    The present work performs a study over 13 tomographic images, using an anthropomorphic head phantom. It contains small lesions in the posterior fossa. Tube current (I [mA]), slice thickness (E [mm]), were the parameters changed among studies, looking for the best acquisition conditions, which permit good lesion detectability, and applying the lowest dose. Air Kerma in air [mGy] was calculated. Image quality was analyzed by both expert criterion and some merit figures. Two of them were global: contrasts to noise ratio (RCR [dB]) and signal to noise ratio (RSR). The rest of the measures used were relatives to the maximum dose condition: The gain in signal to noise ratio (SNR [dB]) and the maximum signal to noise ratio (PSNR [dB]), the normalized mean squared error (NMSE) and the structural similarity index (SSIM). Objective and subjective results were correlated. It is shown that it is possible to reduce the dose using lower values of mAs without affecting lesion detectability and keeping good image quality for the scanner used. An optimized protocol is also proposed for the technology used. (Author) 27 refs.

  18. Manifestações clínicas de pacientes com diagnóstico de neurocisticercose por tomografia computadorizada

    Directory of Open Access Journals (Sweden)

    PFUETZENREITER MÁRCIA REGINA

    1999-01-01

    Full Text Available Foram estudados através de entrevistas semi-estruturadas pacientes submetidos a tomografia computadorizada de crânio em um centro de diagnóstico por imagem na cidade de Lages. Realizaram-se entrevistas em 42 pacientes positivos para cisticercose cerebral e 57 pacientes sem alterações patológicas ao referido exame. Os pacientes com diagnóstico positivo relataram com maior frequência manifestações clínicas relacionadas à neurocisticercose, sendo este fato mais marcante para o sexo feminino, com exceção de convulsões, que ocorreram mais no sexo masculino (19,05% que no feminino (7,14%. A maior percentagem de diagnósticos de formas inativas (83,33% e o relato de sintomas em um tempo mais prolongado entre os entrevistados positivos sugerem que o problema é antigo.

  19. Variações anatômicas das cavidades paranasais à tomografia computadorizada multislice: o que procurar?

    Directory of Open Access Journals (Sweden)

    Christiana Maia Nobre Rocha de Miranda

    2011-08-01

    Full Text Available A tomografia computadorizada multislice é, atualmente, a modalidade de imagem de escolha para a avaliação dos seios paranasais e das estruturas adjacentes. Ela tem sido cada vez mais utilizada para a avaliação das variações anatômicas, identificando-as de forma precisa e com elevados detalhes anatômicos. Algumas variações anatômicas podem predispor a sinusopatias e constituir regiões de alto risco para lesões e complicações durante atos operatórios. Portanto, o reconhecimento dessas variações é de fundamental importância no pré-operatório de cirurgia endoscópica.

  20. Estudo radiográfico e por tomografia computadorizada das formações orais em cães

    OpenAIRE

    Carolina de Oliveira Ghirelli

    2008-01-01

    As neoplasias orais representam a quarta neoplasia mais comum em cães. O diagnóstico por imagem das neoplasias orais é necessário para determinar a extensão do tumor e dos tecidos locais acometidos, auxiliando no prognóstico e planejamento cirúrgico. Atualmente o exame radiográfico é o método diagnóstico mais utilizado por ser mais acessível e menos oneroso, porém o grande número de estruturas no crânio e suas sobreposições dificultam adequada avaliação desta região. A tomografia computadoriz...

  1. Tomografia computadorizada na avaliação da densidade de um solo do semi-árido brasileiro

    Directory of Open Access Journals (Sweden)

    L. Fante Junior

    2002-12-01

    Full Text Available A densidade do solo de amostras indeformadas foi determinada por meio das técnicas de tomografia computadorizada e do torrão impermeabilizado, visando à identificação de processos de compactação do solo e a comparação de métodos. A pesquisa também visou auxiliar um levantamento pedológico elaborado com fins de classificação de terras para irrigação. As amostras de solo foram coletadas da região semi-árida de Petrolina (PE, ao longo de perfis do solo, da superfície até 1 m de profundidade, em camadas de 0,1 m e em duas áreas distintas quanto à sua ocupação vegetal e manejo: (1 vegetação natural (caatinga; (2 área cultivada e irrigada por pivô central. As tomografias foram realizadas com um tomógrafo de primeira geração, constituído por uma fonte de radiação gama de 137Cs e um detetor cintilador de NaI(Tl, com eletrônica padrão de espectrometria gama e sistema de movimentação de amostra controlados por uma interface específica acoplada a um microcomputador. Na área de caatinga, os resultados evidenciam a ocorrência de um adensamento do solo em camadas mais profundas, abaixo de 0,4 m, bem como de uma camada adensada e, ou, compactada entre aproximadamente 0 e 0,4 m, na área cultivada com pivô central, possivelmente em virtude da ação de máquinas e implementos utilizados no preparo e cultivo do solo.

  2. Apendicite aguda: achados na tomografia computadorizada - ensaio iconográfico Acute appendicitis: computed tomography findings - an iconographic essay

    Directory of Open Access Journals (Sweden)

    Marcelo Eustáquio Montandon Júnior

    2007-06-01

    Full Text Available A apendicite aguda é a causa mais comum de dor abdominal aguda que requer intervenção cirúrgica no mundo ocidental. O diagnóstico precoce é essencial para minimizar a morbidade da doença. O uso dos métodos de imagem significou grande avanço no diagnóstico desta entidade, até então avaliada apenas com base na história clínica, exame físico e dados laboratoriais, haja vista que 20% a 33% dos pacientes apresentam sintomas atípicos. O diagnóstico é mais difícil nas crianças, nos idosos e nas mulheres em idade fértil. Os principais métodos de imagem para sua avaliação são a ultra-sonografia e a tomografia computadorizada. Os objetivos deste trabalho são: descrever a fisiopatologia da doença, comentar os principais aspectos técnicos da tomografia computadorizada, demonstrar e ilustrar os achados tomográficos e citar os principais diagnósticos diferenciais.Acute appendicitis is the most important cause of abdominal pain requiring surgical intervention in the Western world. The early diagnosis of this disease is of paramount relevance for minimizing its morbidity. Imaging methods have represented a huge progress in the diagnosis of this entity, which used to be based essentially on clinical history, physical examination and laboratory tests results, considering that 20% to 33% of patients present with atypical symptoms. Diagnostic difficulty is higher in children, the elderly, and women in childbearing age. The main imaging methods for evaluation of acute appendicitis are ultrasound and computed tomography. The present study is aimed at describing the disease physiopathology, commenting main computed tomography technical aspects, demonstrating and illustrating tomographic findings, and describing main differential diagnoses.

  3. Bone formation in axial spondyloarthritis.

    Science.gov (United States)

    Lories, Rik J; Haroon, Nigil

    2014-10-01

    The success of targeted therapies directed against tumor necrosis factor for patients with spondyloarthritis has shifted the focus of physicians and scientists towards the prevention of structural damage to the involved structures, in particular the sacroiliac joints and the spine, to avoid loss of function and disability. Structural damage to the skeleton as witnessed by radiography mainly consists of new bone formation potentially progressively leading to spine or joint ankylosis. This important long-term outcome parameter has been difficult to study, not alone because the time window for change may be long but also because human tissues with direct translational relevance are rarely available. Data from rodent models have identified growth factor signaling pathways as relevant targets. Both human and animal studies have tried to understand the link between inflammation and new bone formation. At the current moment, most evidence points towards a strong link between both but with the question still lingering about the sequence of events, disease triggers, and the interdependence of both features of disease. New discoveries such as a masterswitch T cell population that carries the IL23 receptor and the analysis of auto-antibodies directed again noggin and sclerostin are contributing to innovative insights into the pathophysiology of disease. Long-term data with tumor necrosis factor (TNF) inhibitors also suggest that some window of opportunity may exist to inhibit structural disease progression. All these data provide support for a further critical analysis of the available datasets and boost research in the field. The introduction of novel disease definitions, in particular the characterization of non-radiographic axial spondyloarthritis patients, will likely be instrumental in our further understanding of structural damage. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Anatomic considerations for C2 pedicle screw placement: the use of computerized tomography measurements Consideraciones anatómicas de la cocalización de los tornillos pediculares en C2: uitlización de las medidas de la tomografia computadorizada Considerações anatômicas sobre a localização dos parafusos pediculares em C2: utilização das medidas da tomografia computadorizada

    Directory of Open Access Journals (Sweden)

    Adebukoa Onibokun

    2009-03-01

    eje del pedículo y el ángulo transverso del pedículo (ángulo entre el eje del pedículo y la línea media del cuerpo vertebral. RESULTADOS: el valor promedio del ancho pedicular fue de 5.8 1.2mm. En el sexo masculino el valor promedio del ancho del pedículo (6.0 1.3mm fue mayor comparado con el sexo femenino (5.6 1.1mm, sin embargo no fue observada una diferencia estadística. El valor promedio del ángulo transverso del pedículo fue de 43.9 3.9 grados, siendo de 43.2 3.8 grados en el sexo masculino y 44.7 3.7 grados en el sexo femenino. CONCLUSIÓN: la proyección y determinación en el periodo preoperatorio de las dimensiones anatómicas del pedículo C2 son importantes para la determinación de la trayectoria y dimensiones del local donde el implante será colocado.OBJETIVO: o conhecimento detalhado das características anatômicas do pedículo de C2 é necessário para minimizar os riscos relacionados com a colocação dos parafusos. O objetivo deste trabalho é avaliar as medidas lineares e angulares do eixo axial verdadeiro do pedículo de C2 utilizando tomografia computadorizada. MÉTODOS: foram utilizadas tomografias computadorizadas axiais de 93 pacientes (47 do sexo masculino e 46 do sexo feminino com média de idade de 48 anos. As imagens axiais do pedículo de C2 foram selecionadas para o estudo e os parâmetros estudados foram: largura do pedículo (diâmetro mediolateral do istmo do pedículo perpendicular ao eixo do pedículo e o ângulo tranverso do pedículo (ângulo entre o eixo do pedículo e a linha média do corpo vertebral. RESULTADOS: o valor médio da largura do pedículo foi 5,81,2mm. Nos pacientes de sexo masculino o valor médio da largura do pedículo (6,01,3mm foi maior que nos pacientes de sexo feminino (5,61,1mm. No entanto, não foi observada diferença estatística. O valor médio do ângulo transverso do pedículo foi de 43,93,9 graus, sendo de 43,23,8 graus no sexo masculino e 44,73,7 graus no sexo feminino. CONCLUSÃO: o

  5. Diagnostic value of axial CT scan

    Energy Technology Data Exchange (ETDEWEB)

    Kiuchi, Sousuke (Tsukuba Univ., Sakura, Ibaraki (Japan))

    1983-03-01

    Axial CT scan was used to investigate the radiological details of the temporal bone of 33 patients with chronic otitis media, secondary cholesteatoma, sensorineural hearing loss, Meniere disease, vertigo, facial spasm, and neoplasma. The axial scans showed anatomic details of the temporal bone, and at the same time clearly demonstrated the extent of the soft-tissue masses in the middle ears, as well as the destructions of the ossicles. Bone changes of the anterior walls of the epitympanum and external auditory meatus were more clearly demonstrated than by coronary CT scan. However, the axial scan had the disadvantages in demonstrating the stapes, crista transversa, and the mastoid portion of the facial canal.

  6. Axial force measurement for esophageal function testing

    DEFF Research Database (Denmark)

    Gravesen, Flemming Holbæk; Funch-Jensen, Peter; Gregersen, Hans

    2009-01-01

    force (force in radial direction) whereas the bolus moves along the length of esophagus in a distal direction. Force measurements in the longitudinal (axial) direction provide a more direct measure of esophageal transport function. The technique used to record axial force has developed from external...... documented using imaging modalities such as radiography and scintigraphy. This inconsistency using manometry has also been documented by axial force recordings. This underlines the lack of information when diagnostics are based on manometry alone. Increasing the volume of a bag mounted on a probe...

  7. Stratus optical coherence tomography findings in patients with retinopathy of prematurity Tomografia de coerência óptica em pacientes com retinopatia da prematuridade

    Directory of Open Access Journals (Sweden)

    Aline do Lago

    2007-02-01

    Full Text Available PURPOSE: To describe morphological features of the macula in patients with retinopathy of prematurity. METHODS: Twelve premature babies with retinopathy of prematurity grades I, II and III underwent dilated fundus examination and optical coherence tomography evaluation. RESULTS: In all thirteen eyes of the twelve premature patients optical coherence tomography revealed a condensed retinal pigmented epithelial layer in the macular-foveal area shown by increased reflectivity. In these eyes the retinal layers were not well differentiated. Foveal depression was clearly evident in 23%. CONCLUSIONS: In premature patients with retinopathy of prematurity, optical coherence tomography revealed poorly differentiated layers in the macular region with increased reflectivity in retinal pigmented epithelial-choriocapillaris zone.OBJETIVO: Descrever os aspectos morfológicos da mácula em pacientes com retinopatia da prematuridade (ROP. MÉTODOS: Doze pacientes com retinopatia da prematuridade graus I, II and III foram submetidos a mapeamento de retina e avaliação por tomografia de coerência óptica. RESULTADOS: Em todos os treze olhos de 12 pacientes a tomografia de coerência óptica mostrou a camada do epitélio pigmentar hiperrefletiva, sendo a área macular com maior intensidade. Nesses olhos as camadas da retina não estavam totalmente diferenciadas. A depressão foveal ficou claramente evidente pela tomografia de coerência óptica em 23%. CONCLUSÃO: Nos pacientes prematuros com retinopatia da prematuridade, a tomografia de coerência óptica mostrou as camadas da retina pouco diferenciadas com aumento da refletividade na área macular do complexo epitélio retiniano pigmentar-coriocapilar.

  8. Capacitive axial position and speed transduction system

    International Nuclear Information System (INIS)

    Jimenez D, H.; Flores Ll, H.; Cabral P, A.; Ramirez J, F.J.; Galindo, S.

    1984-01-01

    A new and inexpensive circuit arrangement of a capacitive axial position and speed transduction system is described. Design details and the theory of operation of the device are briefly outlined together with performance results. (author)

  9. Two pad axially grooved hydrostatic bearing

    Science.gov (United States)

    San Andres, Luis A. (Inventor)

    1995-01-01

    A hydrostatic bearing having two axial grooves on opposite sides of the bearing for breaking the rotational symmetry in the dynamic force coefficients thus reducing the whirl frequency ratio and increasing the damping and stiffness of the hydrostatic bearing.

  10. High temperature co-axial winding transformers

    Science.gov (United States)

    Divan, Deepakraj M.; Novotny, Donald W.

    1993-01-01

    The analysis and design of co-axial winding transformers is presented. The design equations are derived and the different design approaches are discussed. One of the most important features of co-axial winding transformers is the fact that the leakage inductance is well controlled and can be made low. This is not the case in conventional winding transformers. In addition, the power density of co-axial winding transformers is higher than conventional ones. Hence, using co-axial winding transformers in a certain converter topology improves the power density of the converter. The design methodology used in meeting the proposed specifications of the co-axial winding transformer specifications are presented and discussed. The final transformer design was constructed in the lab. Co-axial winding transformers proved to be a good choice for high power density and high frequency applications. They have a more predictable performance compared with conventional transformers. In addition, the leakage inductance of the transformer can be controlled easily to suit a specific application. For space applications, one major concern is the extraction of heat from power apparatus to prevent excessive heating and hence damaging of these units. Because of the vacuum environment, the only way to extract heat is by using a cold plate. One advantage of co-axial winding transformers is that the surface area available to extract heat from is very large compared to conventional transformers. This stems from the unique structure of the co-axial transformer where the whole core surface area is exposed and can be utilized for cooling effectively. This is a crucial issue here since most of the losses are core losses.

  11. Axial model in curved space-time

    Energy Technology Data Exchange (ETDEWEB)

    Barcelos-Neto, J.; Farina, C.; Vaidya, A.N.

    1986-12-11

    We study the axial model in a background gravitational field. Using the zeta-function regularization, we obtain explicitly the anomalous divergence of the axial-vector current and the exact generating functional of the theory. We show that, as a consequence of a space-time-dependent metric, all differential equations involved in the theory generalize to their covariantized forms. We also comment on the finite-mass renormalization exhibited by the pseudoscalar field and the form of the fermion propagator.

  12. Dechanneling function for relativistic axially channeled electrons

    International Nuclear Information System (INIS)

    Muralev, V.A.; Telegin, V.I.

    1981-01-01

    Behaviour of the x(t) dechanneling function depending on the depth is theoretically studied. Theoretical consideration of x(t) for axial channeled relativistic electrons in anisotropic medium results in two-dimensional kinetic equation with mixed derivatives of the parabolic type. The kinetic equation in the approximation of the continuous Lindchard model for relativistic axial channeled electrons is numerically solved. The depth dependence of the x(t) dechanneling function is obtained [ru

  13. Axial forces in centrifugal compressor couplings

    Science.gov (United States)

    Ivanov, A. N.; Ivanov, N. M.; Yun, V. K.

    2017-08-01

    The article presents the results of the theoretical and experimental investigation of axial forces arising in the toothed and plate couplings of centrifugal compressor shaft lines. Additional loads on the thrust bearing are considered that can develop in the toothed couplings as a result of coupled rotors misalignment. Design relationships to evaluate the level of axial forces and recommendations for their reduction in the operating conditions are given.

  14. A tomografia de córnea e segmento anterior na propedêutica do exame complementar na avaliação de ectasia

    Directory of Open Access Journals (Sweden)

    Bruno de Freitas Valbon

    2013-02-01

    Full Text Available Descrevemos a importância da tomografia de córnea e segmento anterior na propedêutica do exame complementar na avaliação de ectasia. Esta descrição da interpretação clínica dos índices da tomografia de córnea e segmento anterior (Pentacam - Oculus, Wetzlar, Germany neste relato de caso, demonstra a relevância de uma nova tecnologia na avaliação da córnea e segmento anterior na suspeita de ceratocone. O diagnóstico de ceratocone foi excluído pela análise dos índices tomográficos de ectasia. Detectou-se assimetria entre os lados nasal e temporal por meio da avaliação do mapa de profundidade de câmara anterior. No exame biomicroscópico sob midríase foi constatado subluxação do cristalino, sendo assim devemos estar atentos não somente aos índices tomográficos corneanos na avaliação do exame complementar e sim analisarmos outros dados importantes oferecidos pela tomografia de córnea e segmento anterior.

  15. High harmonic generation from axial chiral molecules.

    Science.gov (United States)

    Wang, Dian; Zhu, Xiaosong; Liu, Xi; Li, Liang; Zhang, Xiaofan; Lan, Pengfei; Lu, Peixiang

    2017-09-18

    Axial chiral molecules, whose stereogenic element is an axis rather than a chiral center, have attracted widespread interest due to their important application, such as asymmetric synthesis and chirality transfer. We investigate high harmonic generation from axial chiral molecules with bichromatic counterrotating circularly polarized laser fields. High harmonic generation from three typical molecules: (Sa)-3-chloropropa-1,2-dien-1-ol, propadiene, and (Ra)-2,3-pentadiene is simulated with time-dependent density-functional theory and strong field approximation. We found that harmonic spectra for 3D oriented axial chiral molecules exhibit obvious circular dichroism. However, the circular dichroism of High harmonic generation from an achiral molecule is much trivial. Moreover, the dichroism of high harmonic generation still exists when axial chiral molecules are 1D oriented,such as (Sa) -3-chloropropa-1,2-dien-1-ol. For a special form of axial chiral molecules with the formula abC=C=Cab (a, b are different substituents), like (Ra)-2,3-pentadiene, the dichroism discriminations disappear when the molecules are only in 1D orientation. The circular dichroism of high harmonic generation from axial chiral molecules is well explained by the trajectory analysis based on the semiclassical three-step mechanism.

  16. Computed Tomography of the diabetic kidney; La Tomografia Computerizzata nello studio del rene diabetico

    Energy Technology Data Exchange (ETDEWEB)

    Angelelli, G.; Stabile Ianora, A.A.; Scardapane, A.; Rotondo, A. [Bari Univ., Bari (Italy). Ist. di Radiologia

    2000-02-01

    The purpose of this work is to investigate whether any morphometric or densitometric are detectable in the kidneys of type 2 diabetic patients. 40 diabetic patients were examined and of 20 non-diabetics (the control group) were submitted to triphasic helical CT for different abdominal conditions. The type 2 diabetic patients were 23 men and 17 women, mean age 62 years, while the nondiabetic controls were 12 men and 8 women, mean age 58 years. All the CT images were analyzed using the Multiplanar Reconstruction (MPR) software. It was evaluated morphometric features, such as the presence of parenchymal or vascular calcifications, axial and coronal renal diameters, coronal renal area, and cortico medullary ratio, and densitometric and functional features, such as unenhanced renal density, cortical and medullary density in the arterial phase, parenchymal density in the nephrographic phase, and contrast elimination. It was also compared the results in the subgroups of patients with those in the controls. Both renal diameters on axial sections and cortical density in the arterial phase were significantly lower in the nephropathic group (p<0.05) than in non-nephropathic patients and control. The patients with shorter duration of their diabetes had significantly greater axial diameters (p<0.05); a longer-standing disease correlated significantly (p<0.05) with smaller axial diameters of kidneys and lower cortical density in the arterial phase. Renal diameters on axial and coronal sections and cortical density in the arterial phase can be useful indices of early nephropathy in diabetic patients. Further studies are warranted to make these findings suitable for use in clinical practice. [Italian] In questo articolo sono presentate le eventuali alterazioni tomodensitometriche a livello renale di pazienti affetti da diabete mellito di tipo 2. Si sono valutate retrospettivamente le immagini TC di 40 soggetti affetti da diabete di tipo 2 (23 maschi, 17 femmine, eta' media 62

  17. Tomografia de coerência óptica na commotio retinae: relato de caso Optical coherence tomography imaging in commotio retinae: case report

    Directory of Open Access Journals (Sweden)

    Celso Morita

    2009-08-01

    Full Text Available O objetivo deste relato é correlacionar achados à tomografia de coerência óptica e prognóstico visual de pacientes com commotio retina e de gravidades diferentes. Dois pacientes do sexo masculino, de 20 e 23 anos com baixa visual unilateral após trauma ocular contuso atribuível a edema de Berlin foram avaliados pela retinografia e tomografia de coerência óptica. A acuidade visual no olho afetado era de 20/25 no primeiro paciente e conta dedos a 2 metros no segundo. O exame oftalmológico revelou uveíte traumática e, na fundoscopia, evidenciaram-se opacificação retiniana moderada no primeiro caso e grave no segundo. A tomografia de coerência óptica confirmou discreta diminuição da depressão foveal no primeiro caso e desorganização das camadas retinianas no segundo. Houve resolução anatômica e funcional completa a tomografia de coerência óptica no primeiro paciente, enquanto o segundo evoluiu com baixa visual permanente e desorganização da arquitetura retiniana. A tomografia de coerência óptica é um exame complementar útil na avaliação do trauma retiniano, ajudando a entender sua fisiopatologia e predizer prognóstico a partir da análise anatômica da região acometida.The purpose of this case report was to correlate optical coherence tomography findings and visual outcomes of patients with different degrees of commotio retinae. A 20-year-old male and a 23-year-old male that presented with decreased vision due to Berlin's edema after blunt ocular trauma were evaluated by optical coherence tomography and retinography. The visual acuity in the affected eye was 20/25 in the first patient and counting fingers in the second one. The ophthalmic examination showed traumatic uveitis and fundoscopy revealed mild retinal opacification in the first case and severe opacification in the latter. The optical coherence tomography confirmed the reduction of foveal depression on the first case and the disarrangement of all retinal

  18. Vector and axial constants of the baryon decuplet

    International Nuclear Information System (INIS)

    Belyaev, V.M.; Blok, B.Y.; Kogan, Y.I.

    1985-01-01

    On the basis of the QCD sum rules for the polarization operator in external axial and vector fields we determine the vector and axial transition constants in the 3/2 + baryon decuplet. We show that the renormalization of the axial constant is due to the interaction of the external axial field with the quark condensate

  19. Nucleon axial form factor from lattice QCD

    International Nuclear Information System (INIS)

    Liu, K.F.; Dong, S.J.; Draper, T.; Wu, J.M.; Wilcox, W.

    1994-01-01

    Results for the isovector axial form factors of the proton from a lattice QCD calculation are presented for both the point-split and local currents. They are obtained on a quenched 16 3 x24 lattice at β=6.0 with Wilson fermions for a range of quark masses from strange to twice the charm mass. For each quark mass, we find that the axial form factor falls off slower than the corresponding proton electric form factor. Results extrapolated to the chiral limit show that the q 2 dependence of the axial form factor agrees quite well with experiment. The axial vector coupling constant g A calculated for the point-split and local currents is 1.20±0.11 and 1.18±0.11. The central values are 4% and 6% smaller than the experimental value of 1.254, respectively. We also consider the large ma correction and renormalization for the axial vector current of heavy quarks

  20. Optimization of residual heat removal pump axial thrust and axial bearing

    International Nuclear Information System (INIS)

    Schubert, F.

    1996-01-01

    The residual heat removal (RHR) pumps of German 1300 megawatt pressurized-water reactor (PWR) power plants are of the single stage end suction type with volute casing or with diffuser and forged circular casing. Due to the service conditions the pumps have to cover the full capacity range as well as a big variation in suction static pressure. This results in a big difference in the axial thrust that has to be borne by the axial bearing. Because these pumps are designed to operate without auxiliary systems (things that do not exist can not fail), they are equipped with antifriction bearings and sump oil lubrication. To minimize the heat production within the bearing casing, a number of PWR plants have pumps with combined axial/radial bearings of the ball type. Due to the fact that the maximum axial thrust caused by static pressure and hydrodynamic forces on the impeller is too big to be borne by that type of axial bearing, the impellers were designed to produce a hydrodynamic axial force that counteracts the static axial force. Thus, the resulting axial thrust may change direction when the static pressure varies

  1. Optimization of residual heat removal pump axial thrust and axial bearing

    Energy Technology Data Exchange (ETDEWEB)

    Schubert, F.

    1996-12-01

    The residual heat removal (RHR) pumps of German 1300 megawatt pressurized-water reactor (PWR) power plants are of the single stage end suction type with volute casing or with diffuser and forged circular casing. Due to the service conditions the pumps have to cover the full capacity range as well as a big variation in suction static pressure. This results in a big difference in the axial thrust that has to be borne by the axial bearing. Because these pumps are designed to operate without auxiliary systems (things that do not exist can not fail), they are equipped with antifriction bearings and sump oil lubrication. To minimize the heat production within the bearing casing, a number of PWR plants have pumps with combined axial/radial bearings of the ball type. Due to the fact that the maximum axial thrust caused by static pressure and hydrodynamic forces on the impeller is too big to be borne by that type of axial bearing, the impellers were designed to produce a hydrodynamic axial force that counteracts the static axial force. Thus, the resulting axial thrust may change direction when the static pressure varies.

  2. Wave propagation in axially moving periodic strings

    DEFF Research Database (Denmark)

    Sorokin, Vladislav S.; Thomsen, Jon Juel

    2017-01-01

    The paper deals with analytically studying transverse waves propagation in an axially moving string with periodically modulated cross section. The structure effectively models various relevant technological systems, e.g. belts, thread lines, band saws, etc., and, in particular, roller chain drives...... for diesel engines by capturing both their spatial periodicity and axial motion. The Method of Varying Amplitudes is employed in the analysis. It is shown that the compound wave traveling in the axially moving periodic string comprises many components with different frequencies and wavenumbers....... This is in contrast to non-moving periodic structures, for which all components of the corresponding compound wave feature the same frequency. Due to this "multi-frequency" character of the wave motion, the conventional notion of frequency band-gaps appears to be not applicable for the moving periodic strings. Thus...

  3. Axial pico turbine - construction and experimental research

    Science.gov (United States)

    Peczkis, G.; Goryca, Z.; Korczak, A.

    2017-08-01

    The paper concerns axial water turbine of power equal to 1 kW. The example of axial water turbine constructional calculations was provided, as well as turbine rotor construction with NACA profile blades. The laboratory test rig designed and built to perform measurements on pico turbine was described. The turbine drove three-phase electrical generator. On the basis of highest efficiency parameters, pico turbine basic characteristics were elaborated. The experimental research results indicated that pico turbine can achieve maximum efficiency close to the values of larger water turbines.

  4. Axial Vircator for Electronic Warfare Applications

    Directory of Open Access Journals (Sweden)

    L. Drazan

    2009-12-01

    Full Text Available This paper deals with a high power microwave generator with virtual cathode – vircator in axial release for electronic warfare applications. The classification of directed energy weapons microwave (DEWM is introduced together with basic block diagrams of a particular class of DEWM. In the paper, methods for designing vircator pulsed power supply, axial vircator structure, measurement methods and experimental results are presented. The vircator in electromagnetic ammunition is powered by magneto-cumulative generator and in weapons for defense of objects (WDO, it is powered by Marx generator. The possible applications of a vircator in the DEWM area are discussed.

  5. LINFOMAS PULMONARES: CORRELAÇÃO DA TOMOGRAFIA COMPUTADORIZADA DE ALTA RESOLUÇÃO COM A ANATOMOPATOLOGIA

    Directory of Open Access Journals (Sweden)

    Marchiori Edson

    2002-01-01

    Full Text Available Neste trabalho são descritos os aspectos tomográficos de alta resolução dos linfomas pulmonares e feita correlação com os achados anatomopatológicos. Com este objetivo, foram revisados as tomografias computadorizadas de alta resolução do tórax e os dados histopatológicos de dez pacientes com diagnóstico confirmado de linfoma não-Hodgkin ou de doença de Hodgkin. Os resultados obtidos foram confrontados com os descritos na literatura. Os achados radiológicos mais comumente vistos neste estudo foram as consolidações parenquimatosas, localizadas, com broncogramas aéreos de permeio (n = 8. Em menor freqüência, foram encontrados múltiplos nódulos parenquimatosos (n = 4, espessamento peribroncovascular (n = 3 e opacidades em vidro fosco (n = 2. Na correlação com a anatomia patológica, as consolidações corresponderam a preenchimento alveolar por células neoplásicas, o espessamento peribroncovascular se deveu a infiltração das bainhas peribroncovasculares por células linfomatosas e a atenuação em vidro fosco se associou com infiltração dos septos alveolares por tais células.

  6. Computerized tomography findings in Fahr's syndrome Achados da tomografia computadorizada na síndrome de Fahr

    Directory of Open Access Journals (Sweden)

    Andréia V. Faria

    2004-09-01

    Full Text Available We analyzed computerized tomography (CT findings in six patients with Fahr's syndrome. They presented calcifications in basal ganglia, dentate nucleus, subcortical region and semioval center, due to alteration in calcium metabolism or due to senile relative hypoxemic state. The image pattern was not strictly related with etiology, although some differences in dystrophic senile calcifications (the only one present in semioval center and absent in subcortical region. CT is an easy exam, has maximum sensitivity and allows diagnosis, contributing to early treatment of many etiologies of Fahr's syndrome.Analisamos os achados de tomografia computadorizada (TC de seis pacientes com síndrome de Fahr. Eles apresentaram calcificações nos gânglios da base, núcleo denteado, região subcortical e centro semi-oval, devidas a distúrbios no metabolismo do cálcio ou a estado de hipóxia relativa, por senilidade. O padrão de imagem não apresenta relação clara com a etiologia, apesar de algumas diferenças no caso das calcificações distróficas senis (as únicas presentes nos centros semi-ovais e ausentes na região subcortical. TC é um exame de fácil realização, máxima sensibilidade e permite o diagnóstico, contribuindo para o tratamento precoce de muitas das etiologias da síndrome de Fahr.

  7. Positron Emission Tomography (PET) in the oncologic clinical practice; Tomografia por Emision de Positrones (PET) en la practica clinica oncologica

    Energy Technology Data Exchange (ETDEWEB)

    Serna M, J.A.; Luviano, C.; Martinez V, D. [Hospital Angeles del Pedregal Mexico DF (Mexico); Maldonado S, A. [Centro PET Complutense, Madrid (Spain)

    2005-07-01

    We intended to determine the frequency with that the computer axial tomography (TAC), it was able to visualize the lesions extra neoplasia detected by the PET tomography in patients with fully identified primary malignant neoplasia. (Author)

  8. Axial crystals macroscopic symmetry and tensor properties

    Czech Academy of Sciences Publication Activity Database

    Janovec, Václav

    2017-01-01

    Roč. 90, č. 1 (2017), s. 1-10 ISSN 0141-1594 Institutional support: RVO:68378271 Keywords : axial * polar * pseudopolar * chiral * enantiomorphism * optical activity Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 1.060, year: 2016

  9. Optimisation of efficiency of axial fans

    NARCIS (Netherlands)

    Kruyt, Nicolaas P.; Pennings, P.C.; Faasen, R.

    2014-01-01

    A three-stage research project has been executed to develop ducted axial-fans with increased efficiency. In the first stage a design method has been developed in which various conflicting design criteria can be incorporated. Based on this design method, an optimised design has been determined

  10. The design of axial shaftless pump

    Science.gov (United States)

    Schmirler, Michal; Netrebska, Hana

    The axial shaftless pump with a rotary casing has been proposed. The pump is unique in its small space requirements and the ability to draw a liquid with a high content of impurities and fibers. Modern motor with an external commutation was used to propel the pump rotor. The pump can be used for both pumping of liquids and marine propulsion.

  11. VERY SLOW SPEED AXIAL MOTION RELUCTANCE MOTOR

    African Journals Online (AJOL)

    Dr Obe

    1984-09-01

    Sep 1, 1984 ... VERY SLOW SPEED AXIAL MOTION RELUCTANCE MOTOR by. L. A. Agu. Electrical Engineering Department. University of Nigeria, Nsukka. ABSTRACT. This paper presents the scheme for a very slow speed linear machine which uses conventional laminations and with which speeds of the same low.

  12. Aryabha~ and Axial Rotation of Earth

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 11; Issue 4. Aryabhata and Axial Rotation of Earth - Naksatra Dina (the Sidereal Day). Amartya Kumar Dutta. General Article Volume 11 Issue 4 April 2006 pp 56-74. Fulltext. Click here to view fulltext PDF. Permanent link:

  13. Aryabhala and Axial Rotation of Earth

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 11; Issue 3. Aryabhata and Axial Rotation of Earth - Khagola (The Celestial Sphere). Amartya Kumar Dutta. General Article Volume 11 Issue 3 March 2006 pp 51-68. Fulltext. Click here to view fulltext PDF. Permanent link:

  14. The axial polarizability of nucleons and nuclei

    International Nuclear Information System (INIS)

    Ericson, M.; Figureau, A.

    1981-02-01

    The part of the static nuclear axial polarizability arising from the nucleonic excitations is derived from the low energy expansion of the πN amplitude. It is shown that the contribution of the Δ intermediate state, though dominant, does not saturate the nucleonic response. A similar effect, though more pronounced, is known to occur for the magnetic susceptibility

  15. Excitation modes in non-axial nuclei

    International Nuclear Information System (INIS)

    Leviatan, A.; Ginnochio, J.N.

    1990-01-01

    Excitation modes of non-axial quadrupole shapes are investigated in the framework of interacting boson models. Both γ-unstable and γ-rigid nuclear shapes are considered for systems with one type of boson as well as with proton-neutron bosons. 6 refs

  16. Excitation modes in non-axial nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Leviatan, A.; Ginnochio, J.N.

    1990-01-01

    Excitation modes of non-axial quadrupole shapes are investigated in the framework of interacting boson models. Both {gamma}-unstable and {gamma}-rigid nuclear shapes are considered for systems with one type of boson as well as with proton-neutron bosons. 6 refs.

  17. AERODYNAMIC DESIGN OF HIGH PRESSRE AXIAL FAN

    Directory of Open Access Journals (Sweden)

    Y. A. Ryzhov

    2014-01-01

    Full Text Available The paper presents the results of numerical studies of flow in a high axial fan of H-2, the geometric parameters are carefully designed by the author. The coefficients of performance, the total pressure, efficiency and capacity. Shows the benefits of fan of H-2 on several other fans, expressed in increased efficiency with equal dimensions and angles of blade setting.

  18. Co-axial, high energy gamma generator

    Science.gov (United States)

    Reijonen, Jani Petteri [Princeton, NJ; Gicquel, Frederic [Pennington, NJ

    2011-08-16

    A gamma ray generator includes an ion source in a first chamber. A second chamber is configured co-axially around the first chamber at a lower second pressure. Co-axially arranged plasma apertures separate the two chambers and provide for restricted passage of ions and gas from the first to the second chamber. The second chamber is formed by a puller electrode having at least one long channel aperture to draw ions from the first chamber when the puller electrode is subject to an appropriate applied potential. A plurality of electrodes rings in the third chamber in third pressure co-axially surround the puller electrode and have at least one channel corresponding to the at least one puller electrode aperture and plasma aperture. The electrode rings increase the energy of the ions to a selected energy in stages in passing between successive pairs of the electrodes by application of an accelerating voltage to the successive pairs of accelerator electrodes. A target disposed co-axially around the plurality of electrodes receives the beam of accelerated ions, producing gamma rays.

  19. Tomografia de coerência óptica em osteoma de coróide: relato de caso Optical coherence tomography in choroidal osteoma: case report

    Directory of Open Access Journals (Sweden)

    Mário Junqueira Nóbrega

    2005-10-01

    Full Text Available Os autores apresentam um caso de osteoma de coróide diagnosticado em paciente do sexo masculino aos 62 anos de idade. A lesão bem delimitada e pouco elevada no pólo posterior do olho direito acompanhada de vascularização interna e neovascularização de coróide em sua borda temporal superior e inferior levaram à suspeita do tumor. O diagnóstico de certeza foi obtido com ecografia A e B e tomografia computadorizada. A tomografia de coerência óptica mostrou alta refletividade em toda a espessura do osteoma bem como elevação do complexo EPR-cório-capilar na região da membrana neovascular subretiniana. Embora os achados tomográficos descritos na literatura e os observados neste caso sejam variados, a tomografia de coerência óptica pode colaborar no diagnóstico de osteoma de coróide.The authors present a case of choroidal osteoma diagnosed in a 62-year-old male patient. A well-defined and slightly elevated lesion located in the posterior pole of the right eye associated with internal vasculature and choroidal neovascularization at its superior and inferior temporal edge were suspicious of the tumor. Confirmation of diagnosis was obtained with A and B ecography and computed tomography. Optical coherence tomography showed high reflectivity through its thickness as well as elevation of the RPE-choriocapillaris complex at the choroidal neovascularization site. Although the literature and the present case show several different tomographical findings, optical coherence tomography can help establishing the diagnosis of choroidal osteoma.

  20. A neurocisticercose no Rio Grande do Norte antes e depois da tomografia computadorizada: apresentação de um caso

    Directory of Open Access Journals (Sweden)

    Ivanilton Galhardo

    1993-11-01

    Full Text Available Os autores fazem referência ao aparecimento de vários casos de neurocisticercose no Rio Grande do Norte após a chegada da tomografia computadorizada (TC ao Estado e enfatizam esse tipo de exame para o diagnóstico da parasitose no sistema nervoso. Apresentam um caso como sendo o primeiro diagnosticado e divulgado no Congresso Brasileiro de Neurologia realizado em Porto Alegre - RS, em outubro-1992. O diagnóstico foi feito, especialmente, pela TC e pela reação de hemaglutinação no líquido céfaloraqueano.

  1. Identificação do sexo de psitacídeos (Amazona aestiva) por meio da avaliação gonadal, utilizando a tomografia computadorizada (TC)

    OpenAIRE

    Lehmkuhl, Ricardo Coelho [UNESP

    2010-01-01

    O objetivo deste estudo foi avaliar a técnica de tomografia computadorizada como meio da visibilização e identificação dos órgãos reprodutivos (gônadas). Utilizou-se 38 aves da espécie Amazona aestiva, com sexo indeterminado e idade superior a cinco anos, para realizar o exame tomográfico utilizou-se anestesia dissociativa a base de quetamina e xilazina. As aves foram posicionadas em decúbito dorsal, e realizou-se os cortes axiais com intervalo de um milímetro. As imagens tomográficas adquiri...

  2. Padronização de um método para mensuração das tábuas ósseas vestibular e lingual dos maxilares na Tomografia Computadorizada de Feixe Cônico (Cone Beam Methodology standardization for measuring buccal and lingual alveolar bone plates using Cone Beam Computed Tomography

    Directory of Open Access Journals (Sweden)

    Marcos Cezar Ferreira

    2010-02-01

    Full Text Available INTRODUÇÃO: a espessura das tábuas ósseas que recobrem os dentes por vestibular e lingual constitui um dos fatores limitantes da movimentação dentária. O avanço tecnológico em Imaginologia permitiu avaliar detalhadamente essas regiões anatômicas por meio da utilização da tomografia computadorizada de feixe cônico (TCFC. OBJETIVO: descrever e padronizar, pormenorizadamente, um método para mensuração das tábuas ósseas vestibular e lingual dos maxilares nas imagens de tomografia computadorizada de feixe cônico. METODOLOGIA: a padronização digital da posição da imagem da face deve constituir o primeiro passo antes da seleção dos cortes de TCFC. Dois cortes axiais de cada maxilar foram empregados para a mensuração da espessura do osso alveolar vestibular e lingual. Utilizou-se como referência a junção cemento-esmalte dos primeiros molares permanentes, tanto na arcada superior quanto na inferior. RESULTADOS: cortes axiais paralelos ao plano palatino foram indicados para avaliação quantitativa do osso alveolar na maxila. Na arcada inferior, os cortes axiais devem ser paralelos ao plano oclusal funcional. CONCLUSÃO: o método descrito apresenta reprodutibilidade para utilização em pesquisas, assim como para a avaliação clínica das repercussões periodontais da movimentação dentária, ao permitir a comparação de imagens pré e pós-tratamento.INTRODUCTION: The thickness of the buccal and lingual bone plates constitutes one of the limiting factors of the orthodontic movement. The imaging technology has permitted the evaluation of this anatomical region, by means of cone beam computed tomography. PURPOSE: To describe and standardize, in details, a method for measuring the buccal and lingual bone plate thickness in CBCT images. METHODOLOGY: Digital standardization of face image should constitute the first step before the selection of CBCT slices. Two axial sections of each jaw were used for measuring the thickness

  3. Review of Axial Burnup Distribution Considerations for Burnup Credit Calculations

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, J.C.; DeHart, M.D.

    2000-03-01

    This report attempts to summarize and consolidate the existing knowledge on axial burnup distribution issues that are important to burnup credit criticality safety calculations. Recently released Nuclear Regulatory Commission (NRC) staff guidance permits limited burnup credit, and thus, has prompted resolution of the axial burnup distribution issue. The reactivity difference between the neutron multiplication factor (keff) calculated with explicit representation of the axial burnup distribution and keff calculated assuming a uniform axial burnup is referred to as the ``end effect.'' This end effect is shown to be dependent on many factors, including the axial-burnup profile, total accumulated burnup, cooling time, initial enrichment, assembly design, and the isotopics considered (i.e., actinide-only or actinides plus fission products). Axial modeling studies, efforts related to the development of axial-profile databases, and the determination of bounding axial profiles are also discussed. Finally, areas that could benefit from further efforts are identified.

  4. Review of Axial Burnup Distribution Considerations for Burnup Credit Calculations

    International Nuclear Information System (INIS)

    Wagner, J.C.; DeHart, M.D.

    2000-01-01

    This report attempts to summarize and consolidate the existing knowledge on axial burnup distribution issues that are important to burnup credit criticality safety calculations. Recently released Nuclear Regulatory Commission (NRC) staff guidance permits limited burnup credit, and thus, has prompted resolution of the axial burnup distribution issue. The reactivity difference between the neutron multiplication factor (keff) calculated with explicit representation of the axial burnup distribution and keff calculated assuming a uniform axial burnup is referred to as the ''end effect.'' This end effect is shown to be dependent on many factors, including the axial-burnup profile, total accumulated burnup, cooling time, initial enrichment, assembly design, and the isotopics considered (i.e., actinide-only or actinides plus fission products). Axial modeling studies, efforts related to the development of axial-profile databases, and the determination of bounding axial profiles are also discussed. Finally, areas that could benefit from further efforts are identified

  5. Estudio comparativo de la fiabilidad y reproducibilidad en la medición de los tamaños dentarios y las medidas de la arcada dentaria entre la tomografía computarizada de haz cónico (CBCT) y un método digital con modelos de estudio

    OpenAIRE

    Tarazona Álvarez, Beatriz

    2011-01-01

    La tomografía computarizada de haz cónico (CBCT) ha supuesto un gran cambio en el diagnóstico ortodóncico ya que nos proporciona información de las estructuras orofaciales en las tres direcciones del espacio, a diferencia de la radiografía convencional. A partir del CBCT podemos obtener modelos tridimensionales que reproducen tridimensionalmente la dentición del paciente, pudiendo realizar mediciones que antes realizábamos sobre los modelos de estudio. Estos nuevos modelos nos permiten realiz...

  6. Piping inspection carriage having axially displaceable sensor

    Science.gov (United States)

    Zollinger, W.T.; Treanor, R.C.

    1994-12-06

    A pipe inspection instrument carriage is described for use with a pipe crawler for performing internal inspections of piping surfaces. The carriage has a front leg assembly, a rear leg assembly and a central support connecting the two assemblies and for mounting an instrument arm having inspection instruments. The instrument arm has a Y-arm mounted distally thereon for axially aligning the inspection instrumentation and a mounting block, a linear actuator and axial movement arm for extending the inspection instruments radially outward to operably position the inspection instruments on the piping interior. Also, the carriage has a rotation motor and gear assembly for rotating the central support and the front leg assembly with respect to the rear leg assembly so that the inspection instruments azimuthally scan the piping interior. The instrument carriage allows performance of all piping inspection operations with a minimum of moving parts, thus decreasing the likelihood of performance failure. 4 figures.

  7. Ventajas de los motores de flujo axial

    Directory of Open Access Journals (Sweden)

    Alberto M Basanta Otero

    2011-03-01

    Full Text Available Es importante conocer sobre una familia de motores que a diferencia de los convencionales o tradicionales no presentanun flujo rotatorio radial, denominados motores de flujo axial. Dichos motores presentan altos valores de par motriz abajas velocidades, una alta eficiencia y alta densidad de potencia. Este trabajo constituye un breve análisis dealgunos motores de la referencia bibliográfica.  Is important to know about a family of motors that at difference whit the traditional, don't have a rotator radial flux,called, axial flux motors. These motors have high torque for low speed, high efficiency and high power density. Thiswork is a brief analysis of several motors of the bibliographic references.

  8. Cross-flow filtration and axial filtration

    International Nuclear Information System (INIS)

    Kraus, K.A.

    1974-01-01

    Two relatively novel alternative solid-liquid-separation techniques of filtration are discussed. In cross-flow filtration, the feed is pumped past the filtering surface. While in axial filtration the filter, mounted on a rotor, is moved with respect to the feed. While large-scale application of the axial filter is still in doubt, it permits with little expenditure of time and money, duplication of many hydrodynamic aspects of cross-flow filtration for fine-particle handling problems. The technique has been applied to municipal wastes, low-level radioactive waste treatment plant, lead removal from industrial wastes, removal of pulp-mill contaminants, textile-mill wastes, and pretreatment of saline waters by lime-soda process in preparation for hyperfiltration. Economics and energy requirements are also discussed

  9. Axial pattern skin flaps in cats.

    Science.gov (United States)

    Remedios, A M; Bauer, M S; Bowen, C V; Fowler, J D

    1991-01-01

    The major direct cutaneous vessels identified in the cat include the omocervical, thoracodorsal, deep circumflex iliac, and caudal superficial epigastric arteries. Axial pattern skin flaps based on the thoracodorsal and caudal superficial epigastric arteries have been developed in cats. Rotation of these flaps as islands allows skin coverage to the carpus and metatarsus, respectively. The thoracodorsal and caudal superficial epigastric flaps provide a practical, one-step option in the reconstruction of large skin defects involving the distal extremities of cats.

  10. Atlanto-axial subluxation: a case report

    OpenAIRE

    Thurlow, Robert D

    1988-01-01

    One of the causes of death in rheumatoid patients is cord compression following atlanto-axial subluxation. Dislocations in the cervical spine are common with patients who have rheumatoid arthritis. Anterior subluxation occurs in up to 35%, followed by vertical subluxation in 22.2%, lateral subluxation in 20.6% and rarely posterior subluxation. A case report is presented to illustrate such a complication.

  11. Axial flux permanent magnet brushless machines

    CERN Document Server

    Gieras, Jacek F; Kamper, Maarten J

    2008-01-01

    Axial Flux Permanent Magnet (AFPM) brushless machines are modern electrical machines with a lot of advantages over their conventional counterparts. They are being increasingly used in consumer electronics, public life, instrumentation and automation system, clinical engineering, industrial electromechanical drives, automobile manufacturing industry, electric and hybrid electric vehicles, marine vessels and toys. They are also used in more electric aircrafts and many other applications on larger scale. New applications have also emerged in distributed generation systems (wind turbine generators

  12. Cervical Spine Axial Rotation Goniometer Design

    OpenAIRE

    Emin Ulaş Erdem; Filiz Can

    2012-01-01

    To evaluate the cervical spine rotation movement is quiet harder than other joints. Configuration and arrangement of current goniometers and devices is not always practic in clinics and some methods are quiet expensive. The cervical axial rotation goniometer designed by the authors is consists of five pieces (head apparatus, chair, goniometric platform, eye pads and camera). With this goniometer design a detailed evaluation of cervical spine range of motion can be obtained. Besides, measureme...

  13. Controle de qualidade e dosimetria em equipamentos de tomografia computadorizada Quality control and dosimetry in computed tomography units

    Directory of Open Access Journals (Sweden)

    Diana Rodrigues de Pina

    2009-06-01

    Full Text Available OBJETIVO: Avaliação de condições dos equipamentos e dosimetria em setores de tomografia computadorizada utilizando protocolos de cabeça, abdome e coluna lombar em pacientes adultos (em três equipamentos distintos e pediátricos com até um ano e meio de vida (em um dos equipamentos avaliados. MATERIAIS E MÉTODOS: Foram estimados o índice de dose em tomografia computadorizada e a dose média em cortes múltiplos, em exames com pacientes adultos, em três distintos equipamentos. Ainda foram estimadas as doses na superfície de entrada e as doses absorvidas em exame de cabeça para pacientes adultos e pediátricos em um dos equipamentos avaliados. RESULTADOS: Foram realizados testes de controle de qualidade, mecânicos, demonstrando que os equipamentos satisfazem as especificações de uso estabelecidas pelas normas vigentes. Os resultados da dosimetria mostraram que valores de dose média em cortes múltiplos excederam em até 109,0% os valores de níveis de referência, apresentando consideráveis variações entre os equipamentos avaliados neste estudo. As doses absorvidas obtidas com protocolos pediátricos são inferiores aos de pacientes adultos, apresentando redução de até 51,0% na tireoide. CONCLUSÃO: Neste estudo foram avaliadas as condições de operação de três equipamentos tomográficos, estabelecendo quais parâmetros devem ser trabalhados para a implantação de um programa de controle de qualidade nas instituições onde esta pesquisa foi desenvolvida.OBJECTIVE: Evaluation of equipment conditions and dosimetry in computed tomography services utilizing protocols for head, abdomen, and lumbar spine in adult patients (in three different units and pediatric patients up to 18 months of age (in one of the units evaluated. MATERIALS AND METHODS: Computed tomography dose index and multiple-scan average dose were estimated in studies of adult patients with three different units. Additionally, entrance surface doses as well as

  14. Axial gravity, massless fermions and trace anomalies

    Energy Technology Data Exchange (ETDEWEB)

    Bonora, L. [International School for Advanced Studies (SISSA), Trieste (Italy); KEK, Tsukuba (Japan). KEK Theory Center; INFN, Sezione di Trieste (Italy); Cvitan, M.; Giaccari, S.; Stemberga, T. [Zagreb Univ. (Croatia). Dept. of Physics; Prester, P.D. [Rijeka Univ. (Croatia). Dept. of Physics; Pereira, A.D. [UERJ-Univ. Estadual do Rio de Janeiro (Brazil). Dept. de Fisica Teorica; UFF-Univ. Federal Fluminense, Niteroi (Brazil). Inst. de Fisica

    2017-08-15

    This article deals with two main topics. One is odd parity trace anomalies in Weyl fermion theories in a 4d curved background, the second is the introduction of axial gravity. The motivation for reconsidering the former is to clarify the theoretical background underlying the approach and complete the calculation of the anomaly. The reference is in particular to the difference between Weyl and massless Majorana fermions and to the possible contributions from tadpole and seagull terms in the Feynman diagram approach. A first, basic, result of this paper is that a more thorough treatment, taking account of such additional terms and using dimensional regularization, confirms the earlier result. The introduction of an axial symmetric tensor besides the usual gravitational metric is instrumental to a different derivation of the same result using Dirac fermions, which are coupled not only to the usual metric but also to the additional axial tensor. The action of Majorana and Weyl fermions can be obtained in two different limits of such a general configuration. The results obtained in this way confirm the previously obtained ones. (orig.)

  15. Axial polarizability and weak currents in nuclei

    International Nuclear Information System (INIS)

    Ericson, M.

    1977-01-01

    The weak interaction nucleonic coupling constants in nuclei are modified by the presence of the neighbouring nucleons. One type of modification is due to the virtual excitation of the isobars through meson exchange. The influence of the isobars is described by means of the nuclear axial polarizability coefficient. This polarizability is known; it is linked to the p-wave πN scattering volume. A relation is derived between the axial nuclear current and the pion field which incorporates the polarizability effects. This relation has an electromagnetic analogue. It is then possible to derive the axial and pseudoscalar coupling constants from a knowledge of the pion field. This field in turn obeys a Klein-Gordon equation which has to include the isobaric excitations. The propagation of the pion field is similar to that of an electromagnetic wave in a dielectric medium. The strong interaction coupling constant is shown to be renormalized in nuclei by the effect of the various types of correlations. (author)

  16. Dynamic control of knee axial deformities

    Directory of Open Access Journals (Sweden)

    E. E. Malyshev

    2013-01-01

    Full Text Available The authors have evaluated the clinical examination of the patients with axial malalignments in the knee by the original method and device which was named varovalgometer. The measurements were conducted by tension of the cord through the spina iliaca anterior superior and the middle of the lower pole of patella. The deviation of the center of the ankle estimated by metal ruler which was positioned perpendicular to the lower leg axis on the level of the ankle joint line. The results of comparison of our method and computer navigation in 53 patients during the TKA show no statistically significant varieties but they differ by average 5° of valgus in clinical examination in comparison with mechanical axis which was identified by computer navigation. The dynamic control of axial malalignment can be used in clinical practice for estimation of the results of treatment of pathology with axial deformities in the knee; for the control of reduction and secondary displacement of the fractures around the knee; for assessment of instability; in planning of correctional osteotomies and intraoperative control of deformity correction; for estimation of Q angle in subluxation and recurrent dislocation of patella; in planning of TKA; during the growth of child it allows to assess the progression of deformity.

  17. Respiratory effects of transient axial acceleration.

    Science.gov (United States)

    Loring, S H; Lee, H T; Butler, J P

    2001-06-01

    Whereas gravity has an inspiratory effect in upright subjects, transient upward acceleration is reported to have an expiratory effect. To explore the respiratory effects of transient axial accelerations, we measured axial acceleration at the head and transrespiratory pressure or airflow in five subjects as they were dropped or lifted on a platform. For the first 100 ms, upward acceleration caused a decrease in mouth pressure and inspiratory flow, and downward acceleration caused the opposite. We also simulated these experimental observations by using a computational model of a passive respiratory system based on anatomical data and normal respiratory characteristics. After 100 ms, respiratory airflow in our subjects became highly variable, no longer varying with acceleration. Electromyograms of thoracic and abdominal respiratory muscles showed bursts of activity beginning 40-125 ms after acceleration, suggesting reflex responses responsible for subsequent flow variability. We conclude that, in relaxed subjects, transient upward axial acceleration causes inspiratory airflow and downward acceleration causes expiratory airflow, but that after ~100 ms, reflex activation of respiratory musculature largely determines airflow.

  18. Atlanto-Axial Subluxation After Adenoidectomy.

    Science.gov (United States)

    Gross, Isabel Theresia; Bahar-Posey, Laleh

    2017-06-01

    Atlanto-axial subluxation is a rare but potentially serious complication after otolaryngological procedures. We are describing a case of a 4-year-old child who developed atlanto-axial subluxation of the cervical spine after adenoidectomy. Our patient underwent adenoidectomy and, 18 days later, presented to the emergency department with her neck tilted to the left in a cock-robin position and complaining of neck pain persisting since the surgery. A multiplanar 3-dimensional computed tomography was obtained and confirmed the diagnosis of an atlanto-axial subluxation (Fielding type 3). She was managed conservatively with the application of a cervical collar, anti-inflammatory medication, and manual reduction under anesthesia later in the course because of persistence of her symptoms. It is important to consider this diagnosis in any child who undergoes ENT surgical procedures complaining of neck pain subsequent to surgery or holding the head in a fixed position persistently after surgery. Early diagnosis is important to reduce the time between the onset of symptoms and reduction to reduce the risk or need for surgical intervention.

  19. The deep structure of Axial Volcano

    Science.gov (United States)

    West, Michael Edwin

    The subsurface structure of Axial Volcano, near the intersection of the Juan de Fuca Ridge and the Cobb-Eickelberg seamount chain in the northeast Pacific, is imaged from an active source seismic experiment. At a depth of 2.25 to 3.5 km beneath Axial lies an 8 km x 12 km region of very low seismic velocities that can only be explained by the presence of magma. In the center of this magma storage chamber at 2--3.5 km below sea floor, the crust is at least 10--20% melt. At depths of 4--5 km there is evidence of additional low concentrations of magma (a few percent) over a larger area. In total, 5--11 km3 of magma are stored in the mid-crust beneath Axial. This is more melt than has been positively identified under any basaltic volcano on Earth. It is also far more than the 0.1--0.2 km3 emplaced during the 1998 eruption. The implied residence time in the magma reservoir of a few hundred to a few thousand years agrees with geochemical trends which suggest prolonged storage and mixing of magmas. The large volume of melt bolsters previous observations that Axial provides much of the material to create crust along its 50 km rift zones. A high velocity ring-shaped feature sits above the magma chamber just outside the caldera walls. This feature is believed to be the result of repeated dike injections from the magma body to the surface during the construction of the volcanic edifice. A rapid change in crustal thickness from 8 to 11 km within 15 km of the caldera implies focused delivery of melt from the mantle. The high flux of magma suggests that melting occurs deeper in the mantle than along the nearby ridge. Melt supply to the volcano is not connected to any plumbing system associated with the adjacent segments of the Juan de Fuca Ridge. This suggests that, despite Axial's proximity to the ridge, the Cobb hot spot currently drives the supply of melt to the volcano.

  20. Aplicación de metodología de modelado 3D utilizando Tomografías Computarizadas para su análisis numérico

    Directory of Open Access Journals (Sweden)

    Ariel Fuerte Hernández

    2014-01-01

    Full Text Available Este trabajo presenta una metodología para la generación de un modelo del segmento lumbar porcino y humano L4-L5 a partir de Tomografías Computarizadas (TC. El uso de la TC como herramienta de biomodelado es una técnica que actualmente es muy usada en el desarrollo de análisis numéricos computacionales mediante programas de Análisis de Elemento Finito (AEF, lo que permite visualizar y analizar estructuras anatómicas simples y/o complejas. Por lo que, la relevancia de este trabajo radica en el hecho de la generación de análisis numéricos biomecánicos con resultados muy cercanos a los análisis experimentales, creando soluciones médicas en el diseño de dispositivos protésicos. Los resultados numéricos muestran una concentración de esfuerzos en el disco intervertebral justo en la zona de las placas terminales, tanto en el caso humano como en el porcino, lo que concuerda con análisis experimentales previos. De este modo, se concluye que los resultados obtenidos mediante esta técnica validan análisis experimentales previos, sin embargo, es necesario tomar en cuenta las características del comportamiento mecánico de los diferentes tejidos biológicos que componen la columna lumbar.

  1. Tomografia computadorizada sem contraste intravenoso no abdome agudo: quando e por que usar When and why use unenhanced computed tomography in patients with acute abdomen

    Directory of Open Access Journals (Sweden)

    Edison de Oliveira Freire Filho

    2006-02-01

    Full Text Available A tomografia computadorizada sem contraste intravenoso tem sido freqüentemente proposta na avaliação inicial de pacientes com suspeita de abdome agudo, ocupando o espaço de outros métodos diagnósticos. Os autores apresentam uma revisão bibliográfica dos principais aspectos e eficácia da tomografia computadorizada sem contraste intravenoso no diagnóstico de apendicite aguda, cólica nefrética, diverticulite, pancreatite aguda, apendicite epiplóica, pneumoperitônio e obstrução intestinal. Discutem quais as vantagens e limitações desta técnica de exame, bem como seus aspectos práticos.The use of unenhanced computed tomography has been frequently recommended for the initial assessment of patients with clinical suspicion of acute abdomen instead of other diagnostic methods. The authors present a review of the literature on the main aspects, advantages, limitations and efficacy of unenhanced computed tomography for the diagnosis of acute appendicitis, renal colic, diverticulitis, acute pancreatitis, primary epiploic appendicitis, pneumoperitoneum and small bowel obstruction. The advantages and limitations of this technique are also discussed.

  2. Aspectos da tomografia de coerência óptica na oftalmia simpática: relato de caso Optical coherence tomography aspects of sympathetic ophthalmia: case report

    Directory of Open Access Journals (Sweden)

    Magno Antônio Ferreira

    2009-06-01

    Full Text Available A oftalmia simpática é uma panuveíte granulomatosa que se inicia após trauma ocular. O prognóstico é reservado e depende do diagnóstico e tratamento precoces. Os autores descrevem um caso de paciente portador de oftalmia simpática no qual foi realizada tomografia de coerência óptica e instituído tratamento precoce, e sugerem que a tomografia de coerência óptica possa corroborar como exame subsidiário no estudo das características da retina de pacientes portadores dessa doença, especialmente em casos de apresentação rara, com descolamento seroso da retina, como manifestação oftalmológica isolada.The sympathetic ophthalmia is a granulomatous panuveitis that starts after ocular trauma. The prognosis is poor and depends of both early diagnosis and treatment. The authors describe one case of a patient with sympathetic ophthalmia using optical coherence tomography who was submitted to early treatment, and it suggests that the optical coherence tomography can corroborate as a ancillary method in the study of retina characteristics in sympathetic ophthalmia disease specially in cases of rare presentation, with serous retinal detachment as an isolated ophthalmological manifestation.

  3. Intrinsic carpal ligaments on MR and multidetector CT arthrography: comparison of axial and axial oblique planes

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ryan K.L.; Griffith, James F.; Ng, Alex W.H.; Law, Eric K.C. [The Chinese University of Hong Kong, Department of Imaging and Interventional Radiology, Prince Of Wales Hospital, Hong Kong (China); Tse, W.L.; Wong, Clara W.Y.; Ho, P.C. [The Chinese University of Hong Kong, Department of Orthopedics and Traumatology, Prince Of Wales Hospital, Hong Kong (China)

    2017-03-15

    To compare axial and oblique axial planes on MR arthrography (MRA) and multidetector CT arthrography (CTA) to evaluate dorsal and volar parts of scapholunate (SLIL) and lunotriquetral interosseous (LTIL) ligaments. Nine cadaveric wrists of five male subjects were studied. The visibility of dorsal and volar parts of the SLIL and LTIL was graded semi-quantitatively (good, intermediate, poor) on MRA and CTA. The presence of a ligament tear was determined on arthrosocopy and sensitivity, specificity and accuracy of tear detection were calculated. Oblique axial imaging was particularly useful for delineating dorsal and volar parts of the LTIL on MRA with overall 'good' visibility increased from 11 % to 78 %. The accuracy of MRA and CTA in revealing SLIL and LTIL tear was higher using the oblique axial plane. The overall accuracy for detecting SLIL tear on CTA improved from 94 % to 100 % and from 89 % to 94 % on MRA; the overall accuracy of detecting LTIL tear on CTA improved from 89 % to 100 % and from 72 % to 89 % on MRA Oblique axial imaging during CT and MR arthrography improves detection of tears in the dorsal and volar parts of both SLIL and LTIL. (orig.)

  4. Validation of computed tomography protocols for simulated mandibular lesions: a comparison study Validação de protocolos de tomografia computadorizada para lesões simuladas em mandíbula: estudo comparativo

    Directory of Open Access Journals (Sweden)

    Andréia Perrella

    2007-06-01

    Full Text Available Computed tomography is the choice technique to assess oral and maxillofacial osseous lesions because it provides hard and soft tissues visualization in one examination without superimposition of surrounding structures. This examination offers a significant advance in maxillofacial lesions detection with an excellent anatomic resolution. The aim of this research was to evaluate the validity of two protocols, in axial sections, in simulated mandibular lesions. Two CT protocols were obtained in dry mandibles in which perforations were done simulating lesions. Two observers, previously calibrated, evaluated the images according to different parameters. The results indicated that the sensitivity and specificity in lesion detection were 100% for both protocols, but the detection of loci number of multilocular lesions and the location and detection of medullar invasion obtained reduced validity values, which were influenced by the acquisition protocol. We concluded that thinner axial slices and reconstructions were more effective in detecting early medullar invasion and loci number. Thicker protocols were not considered appropriate to detect multilocular lesions and early stages of medullar invasion.A tomografia Computadorizada é a técnica de escolha no exame de lesões ósseas orais e maxilo-faciais porque proporciona a visualização de tecidos duros e moles em aquisição única e sem sobreposição de estruturas adjacentes. Este exame oferece um avanço significativo na detecção de lesões maxilo-faciais, com excelente resolução anatômica. O objetivo desta pesquisa foi avaliar a validade de dois protocolos, em secções axiais, em lesões simuladas de mandíbula. Dois protocolos de TC foram obtidos em mandíbulas secas em que foram feitas perfurações, simulando lesões. Dois observadores previamente calibrados avaliaram as imagens seguindo parâmetros diversos. Como resultados pudemos observar que a sensibilidade e a especificidade foram

  5. Axial flow heat exchanger devices and methods for heat transfer using axial flow devices

    Science.gov (United States)

    Koplow, Jeffrey P.

    2016-02-16

    Systems and methods described herein are directed to rotary heat exchangers configured to transfer heat to a heat transfer medium flowing in substantially axial direction within the heat exchangers. Exemplary heat exchangers include a heat conducting structure which is configured to be in thermal contact with a thermal load or a thermal sink, and a heat transfer structure rotatably coupled to the heat conducting structure to form a gap region between the heat conducting structure and the heat transfer structure, the heat transfer structure being configured to rotate during operation of the device. In example devices heat may be transferred across the gap region from a heated axial flow of the heat transfer medium to a cool stationary heat conducting structure, or from a heated stationary conducting structure to a cool axial flow of the heat transfer medium.

  6. QCD plasma parameters in axial gauge

    Energy Technology Data Exchange (ETDEWEB)

    Nachbagauer, H. (Technische Univ., Vienna (Austria). Inst. fuer Theoretische Physik)

    1992-11-01

    Within the framework of imaginary time formalism we investigate the structure of the gluon polarization tensor and relate its structure functions to the dispersion relation of plasma eigenmodes. To one loop order, we calculate the transversal structure function to leading order in the high temperature expansion as well as the first subleading order contribution in the long wavelength limit. The result is used to express the dynamical mass and the damping constant for transversal plasma eigenmodes. The aim of our present paper is a systematic discussion of the gauge fixing vector dependence of the damping constant. In the limit of temporal axial gauge we encounter a negative damping constant contradicting previous results. (orig.).

  7. QCD plasma parameters in axial gauge

    Science.gov (United States)

    Nachbagauer, Herbert

    1992-09-01

    Within the framework of imaginary time formalism we investigate the structure of the gluon polarization tensor and relate its structure functions to the dispersion relation of plasma eigenmodes. To one loop order, we calculate the transversal structure function to leading order in the high temperature expansion as well as the first subleading order contribution in the long wavelength limit. The result is used to express the dynamical mass and the damping constant for transversal plasma eigenmodes. The aim of our present paper is a systematic discussion of the gauge fixing vector dependence of the damping constant. In the limit of temporal axial gauge we encounter a negative damping constant contradicting previous results.

  8. Disordered axial movement in Parkinson's disease.

    OpenAIRE

    Steiger, M J; Thompson, P D; Marsden, C D

    1996-01-01

    Axial motor impairments are a common cause of disability in patients with Parkinson's disease, become more prominent with longer disease duration, and have been said to be less responsive to levodopa replacement therapy. The ability to turn in bed while lying supine before and after dopaminergic stimulation was studied in a group of 36 patients with Parkinson's disease; 23 were in Hoehn and Yahr stages 3-5 when "off", and 13 were in stages 1-2. Turning was also compared with postural stabilit...

  9. Water ingestion into jet engine axial compressors

    Science.gov (United States)

    Tsuchiya, T.; Murthy, S. N. B.

    1982-01-01

    An axial flow compressor has been tested with water droplet ingestion under a variety of conditions. The results illustrate the manner in which the compressor pressure ratio, efficiency and surging characteristics are affected. A model for estimating the performance of a compressor during water ingestion has been developed and the predictions obtained compare favorably with the test results. It is then shown that with respect to five droplet-associated nonlinearly-interacting processes (namely, droplet-blade interactions, blade performance changes, centrifugal action, heat and mass transfer processes and droplet break-up), the initial water content and centrifugal action play the most dominant roles.

  10. Ankylosing Spondylitis versus Nonradiographic Axial Spondyloarthritis

    DEFF Research Database (Denmark)

    Glintborg, Bente; Sørensen, Inge J; Østergaard, Mikkel

    2017-01-01

    OBJECTIVE: To compare baseline disease activity and treatment effectiveness in biologic-naive patients with nonradiographic axial spondyloarthritis (nr-axSpA) and ankylosing spondylitis (AS) who initiate tumor necrosis factor inhibitor (TNFi) treatment and to study the role of potential confounders....../disease duration/TNFi-type/smoking/baseline disease activity) on TNFi adherence and response [e.g., Bath Ankylosing Spondylitis Activity Index (BASDAI) 50%/20 mm]. RESULTS: The study included 1250 TNFi-naive patients with axSpA (29% nr-axSpA, 50% AS, 21% lacked radiographs of sacroiliac joints). Patients...

  11. Cervical Spine Axial Rotation Goniometer Design

    Directory of Open Access Journals (Sweden)

    Emin Ulaş Erdem

    2012-06-01

    Full Text Available To evaluate the cervical spine rotation movement is quiet harder than other joints. Configuration and arrangement of current goniometers and devices is not always practic in clinics and some methods are quiet expensive. The cervical axial rotation goniometer designed by the authors is consists of five pieces (head apparatus, chair, goniometric platform, eye pads and camera. With this goniometer design a detailed evaluation of cervical spine range of motion can be obtained. Besides, measurement of "joint position sense" which is recently has rising interest in researches can be made practically with this goniometer.

  12. Medullary sponge kidney on axial computed tomography

    International Nuclear Information System (INIS)

    Ginalski, J.-M.; Schnyder, Pierre; Portmann, Luc; Jaeger, Philippe

    1991-01-01

    To evaluate features of medullary sponge kidney (MSK) on computed tomography (CT), 4-mm-thick axial slices without intravenous contrast material were 1st made in 13 patients through 24 kidneys which showed images of MSK on excretory urograms. On CT, papillary calcifications were found in 11 kidneys. In 5 of these, the calcifications were not detectable on plain films. Some hyperdense papillae (attenuation value 55-70 Hounsfield units) without calcification were found in 4 other kidneys. 9 kidneys appeared normal. 10 of the 14 kidneys were reexamined by a 2nd series of 4-mm-thick axial slices, 5 min after intravenous injection of 50 ml of Urografin. Images suggesting possible ectasia of precaliceal tubules were found in only 4 kidneys. These images appear much less obvious and characteristic on CT than on excretory urogram and do nothing more than suggest the possibility of MSK. In conclusion, the sensitivity of CT in the detection of MSK is markedly lower than that of excretory urography. In the most florid cases of the disease, CT can only show images suggesting the possibility of MSK. On the other hand, CT appears much more sensitive than plain films and tomograms of excretory in the detection of papillary calcifications, the most frequent complication of MSK. (author). 13 refs.; 3 figs

  13. Axial tomography in live cell laser microscopy

    Science.gov (United States)

    Richter, Verena; Bruns, Sarah; Bruns, Thomas; Weber, Petra; Wagner, Michael; Cremer, Christoph; Schneckenburger, Herbert

    2017-09-01

    Single cell microscopy in a three-dimensional (3-D) environment is reported. Cells are grown in an agarose culture gel, located within microcapillaries and observed from different sides after adaptation of an innovative device for sample rotation. Thus, z-stacks can be recorded by confocal microscopy in different directions and used for illustration in 3-D. This gives additional information, since cells or organelles that appear superimposed in one direction, may be well resolved in another one. The method is tested and validated with single cells expressing a membrane or a mitochondrially associated green fluorescent protein, or cells accumulating fluorescent quantum dots. In addition, axial tomography supports measurements of cellular uptake and distribution of the anticancer drug doxorubicin in the nucleus (2 to 6 h after incubation) or the cytoplasm (24 h). This paper discusses that upon cell rotation an enhanced optical resolution in lateral direction compared to axial direction can be utilized to obtain an improved effective 3-D resolution, which represents an important step toward super-resolution microscopy of living cells.

  14. Axial vessel widening in arborescent monocots.

    Science.gov (United States)

    Petit, Giai; DeClerck, Fabrice A J; Carrer, Marco; Anfodillo, Tommaso

    2014-02-01

    Dicotyledons have evolved a strategy to compensate for the increase in hydraulic resistance to water transport with height growth by widening xylem conduits downwards. In monocots, the accumulation of hydraulic resistance with height should be similar, but the absence of secondary growth represents a strong limitation for the maintenance of xylem hydraulic efficiency during ontogeny. The hydraulic architecture of monocots has been studied but it is unclear how monocots arrange their axial vascular structure during ontogeny to compensate for increases in height. We measured the vessel lumina and estimated the hydraulic diameter (Dh) at different heights along the stem of two arborescent monocots, Bactris gasipaes (Kunth) and Guadua angustifolia (Kunth). For the former, we also estimated the variation in Dh along the leaf rachis. Hydraulic diameter increased basally from the stem apex to the base with a scaling exponent (b) in the range of those reported for dicot trees (b = 0.22 in B. gasipaes; b = 0.31 and 0.23 in G. angustifolia). In B. gasipaes, vessels decrease in Dh from the stem's centre towards the periphery, an opposite pattern compared with dicot trees. Along the leaf rachis, a pattern of increasing Dh basally was also found (b = 0.13). The hydraulic design of the monocots studied revealed an axial pattern of xylem conduits similar to those evolved by dicots to compensate and minimize the negative effect of root-to-leaf length on hydrodynamic resistance to water flow.

  15. Modeling the axial offset anomaly in PWRs

    Energy Technology Data Exchange (ETDEWEB)

    Blok, J.; Chauffriat, S.; Frattini, P. [EPRI, Palo Alto, CA (United States)

    2002-07-01

    Axially un-symmetrical flux depression is defined as axial offset anomaly (AOA) in PWRs. The effect has only been observed in PWR reactor cores operated at high power duty. The threat of AOA limits the aggressiveness of core design, and in extreme form, the effect can decrease shutdown margin near end of cycle (EOC) sufficiently to mandate power reduction. AOA is ultimately the result of boron hideout on fuel. Studies have confirmed that sufficient boron hideout to produce measurable AOA requires relatively large amounts of corrosion products to deposit on the fuel. Because corrosion product deposition is favored in the boiling upper regions of the (high duty) core, the amount of boron uptake in these regions is large in proportion, and core reactivity is affected disproportionately in the upper region of the core. This paper explores possible mechanisms for deposition of corrosion products on fuel and the consequent incorporation of boron compounds. The proposed mechanisms are viewed in the context of corrosion product samples from the Callaway Cycle 9, one of the PWR fuel cycles that exhibited the most severe AOA to date. (author)

  16. Tomografia computadorizada no diagnóstico da otosclerose retrofenestral Computed tomography in the diagnosis of retrofenestral otosclerosis

    Directory of Open Access Journals (Sweden)

    Andy de Oliveira Vicente

    2004-01-01

    Full Text Available OBJETIVO: Identificar os principais achados tomográficos da otosclerose retrofenestral. MÉTODO: Estudo prospectivo multicêntrico com tomografia computadorizada (TC de ossos temporais em 54 pacientes com diagnóstico clínico e cirúrgico de otosclerose. Foi realizada uma análise tomográfica, em que foi avaliada a utilidade da TC no diagnóstico radiológico da otosclerose retrofenestral, sendo verificados os principais sítios de lesões dessa doença. Foram incluídos neste estudo 22 pacientes submetidos à TC de ossos temporais para investigação de outras afecções otológicas, que constituíram o grupo controle. RESULTADOS: Os achados tomográficos foram bilaterais na maioria dos casos e o foco retrofenestral mais prevalente foi o foco pericoclear. CONCLUSÕES: A TC monstrou-se útil na identificação dos focos retrofenestrais. A evidência tomográfica desses focos juntamente com o envolvimento endosteal da cóclea podem sugerir uma maior atividade da doença.AIM: To identify the main tomographic findings of retrofenestral otosclerosis. METHODS: A prospective and multicentric study using computed tomography (CT of the temporal bone in 54 patients with a clinical and surgical diagnosis of otosclerosis. A tomographic analysis has been performed to evaluate the utility of CT scans in diagnosing retrofenestral otosclerosis, verifying the sites of predilection for otosclerotic lesions. In this study, 22 patients undergone CT scans of temporal bones have been included in order to investigate other otologic diseases and have constituted the control group. RESULTS: The tomographic findings were mostly bilateral and the retrofenestral focus more prevalent was the pericochlear focus. CONCLUSIONS: The CT scan was useful in the identification of the retrofenestral focuses. The evidence of this focuses and the presence of the endosteal involvement of the cochlea can suggest a higher activity of the disease.

  17. Proptose ocular como manifestação clínica de tumores malignos extra-orbitários: estudo pela tomografia computadorizada

    Directory of Open Access Journals (Sweden)

    Baptista Ana Célia

    2003-01-01

    Full Text Available Doenças sistêmicas, doenças orbitárias primárias e lesões extra-orbitárias com extensão secundária para a órbita podem causar proptose ocular. Foram estudados, por tomografia computadorizada, 11 pacientes com proptose ocular causada por tumores malignos extra-orbitários, sem qualquer tratamento prévio do tumor. Houve predomínio de neoplasias não-epiteliais (82%, tendo sido três rabdomiossarcomas (27% e três linfomas não-Hodgkin (27%. Outros sarcomas estiveram presentes em dois casos (18%, seguidos por linfoma de Burkitt (9%, carcinoma epidermóide (9% e carcinoma pouco diferenciado (9%. Nove tumores (82% tiveram origem nas cavidades sinonasais, a maioria (cinco casos com origem no seio etmoidal. Proptose ocular foi a única alteração oftálmica em quatro casos (36%, e um paciente teve proptose ocular bilateral como único sinal da doença. Dezessete órbitas foram acometidas pelos 11 tumores, já que seis pacientes tiveram comprometimento orbitário tumoral bilateral. Os tumores se estenderam às órbitas preferencialmente através da parede óssea orbitária (16 órbitas; 94%. Das 17 órbitas comprometidas, a maioria (59% teve todos os compartimentos lesados. Em 16 órbitas o tumor apresentou situação extraconal. À tomografia computadorizada, proptose ocular esteve presente em 15 das 17 órbitas (88%, tendo sido bilateral em quatro casos (oito órbitas. Houve predomínio de proptose ocular grau 2 à tomografia computadorizada (sete pacientes; 47%. Um total de 44 regiões crânio-faciais foi comprometido, além da órbita e do sítio de origem da neoplasia, indicando a grande extensão loco-regional desses tumores no momento do diagnóstico.

  18. Análise da castanha do cajueiro por tomografia de ressonância magnética Cashew nut analysis by magnetic resonance tomography

    Directory of Open Access Journals (Sweden)

    João Rodrigues de Paiva

    2004-11-01

    Full Text Available O objetivo deste trabalho foi avaliar a técnica de tomografia de ressonância magnética na análise de castanhas de cajueiro, em relação ao método tradicional, visando sua aplicação na seleção de clones. Amostras de castanhas de 40 clones de cajueiro comum, colhidas na safra de 2002, foram analisadas por ambos os métodos. Pelo método tradicional, a maioria dos clones apresentou altos e médios valores dos indicadores industriais massa de castanha, massa de amêndoa e rendimento industrial e baixos índices de quebra das amêndoas. Pela tomografia, a maioria dos clones apresentou castanhas com espaços vazios entre a amêndoa e o endocarpo, que podem proteger a amêndoa durante a decorticação. Os resultados dos dois métodos foram complementares, e a tomografia, além de alternativa promissora na avaliação da qualidade de castanha, pode subsidiar outras áreas de pesquisa relacionadas ao estudo da castanha.The objective of this work was to evaluate the technique of magnetic resonance tomography for cashew nut analysis, compared to the traditional method of clone selection. Samples of cashew nut from 40 clones harvested in 2002 were analyzed using both methods. Using traditional method most of clones showed high and medium values of the industrial indicators nut and seed mass and industrial yield and low values of seed breakage. By magnetic resonance tomography majority of clones showed cashew nuts with empty spaces between the nut and the endocarp, which can protect the seed during decortication. The results for the two methods were complementary and the tomography, besides being a promising option for the quality evaluation of cashew nut, can give support to other researches related to cashew nut study.

  19. Axial dispersion in a Kureha Crystal Purifier (KCP)

    Science.gov (United States)

    Otawara, K.; Matsuoka, T.

    2002-04-01

    It is widely accepted that the degree of axial back-mixing in the equipment affects the performance of a column crystallizer. Specifically, small such mixing is inevitable for obtaining highly pure crystal. In fact, it is believed that scale-up of some column crystallizers has been terminated due to the large axial back-mixing or maldistribution. Thus, experiments have been performed for estimating axial dispersion coefficients of liquid phase representing axial back-mixing in the column of a Kureha Crystal Purifier (KCP). The effect of the column diameter on such coefficients has been investigated and it has become evident that the axial back-mixing in the column is more significant in the larger column. Nevertheless, the results have also indicated that the axial back-mixing in KCPs of industrial sizes can be substantially smaller than those in other types of column crystallizers.

  20. Axial stress corrosion cracking forming method to metal tube

    International Nuclear Information System (INIS)

    Araki, Kumiko

    1998-01-01

    Generally, it is more difficult in a metal tube, to intentionally cause a stress corrosion cracking in axial direction than in circumferential direction. In the present invention, a bevel is formed on a metal tube and welding is conducted in circumferential direction along the bevel, and welding is conducted in axial direction partially to the portion welded in circumferential direction. Namely, a bevel is formed in circumferential direction to an abutting portion of thick-walled metal tubes with each other, welding is conducted in circumferential direction along the bevel, and welding is conducted in axial direction partially to a portion welded in circumferential direction. With such procedures, since tensile stress in the circumferential direction is increased partially at a portion welded in axial direction, stress corrosion cracking is caused in axial direction at the portion. Then, stress corrosion cracking in axial direction can thus be formed on the thick-walled metal tube. (N.H.)

  1. Revisiting the vector and axial-vector vacuum susceptibilities

    International Nuclear Information System (INIS)

    Chang Lei; Liu Yuxin; Sun Weimin; Zong Hongshi

    2008-01-01

    We re-investigate the vector and axial-vector vacuum susceptibilities by taking advantage of the vector and axial-vector Ward-Takahashi identities. We show analytically that, in the chiral limit, the vector vacuum susceptibility is zero and the axial-vector vacuum susceptibility equals three fourths of the square of the pion decay constant. Besides, our analysis reproduces the Weinberg sum rule

  2. Aerodynamic Modelling and Optimization of Axial Fans

    DEFF Research Database (Denmark)

    Sørensen, Dan Nørtoft

    A numerically efficient mathematical model for the aerodynamics oflow speed axial fans of the arbitrary vortex flow type has been developed.The model is based on a blade-element principle, whereby therotor is divided into a number of annular streamtubes.For each of these streamtubes relations...... and integrated propertiesshow that the computed results agree well with the measurements.Integrating a rotor-only version of the aerodynamic modelwith an algorithm for numerical designoptimization, enables the finding of an optimum fan rotor.The angular velocity of the rotor, the hub radius and the spanwise...... of fan efficiency in a design interval of flow rates,thus designinga fan which operates well over a range of different flow conditions.The optimization scheme was used to investigate the dependence ofmaximum efficiency on1: the number of blades,2: the width of the design interval and3: the hub radius...

  3. Geometric inequalities for axially symmetric black holes

    International Nuclear Information System (INIS)

    Dain, Sergio

    2012-01-01

    A geometric inequality in general relativity relates quantities that have both a physical interpretation and a geometrical definition. It is well known that the parameters that characterize the Kerr-Newman black hole satisfy several important geometric inequalities. Remarkably enough, some of these inequalities also hold for dynamical black holes. This kind of inequalities play an important role in the characterization of the gravitational collapse; they are closely related with the cosmic censorship conjecture. Axially symmetric black holes are the natural candidates to study these inequalities because the quasi-local angular momentum is well defined for them. We review recent results in this subject and we also describe the main ideas behind the proofs. Finally, a list of relevant open problems is presented. (topical review)

  4. Collimated trans-axial tomographic scintillation camera

    International Nuclear Information System (INIS)

    1980-01-01

    The objects of this invention are first to reduce the time required to obtain statistically significant data in trans-axial tomographic radioisotope scanning using a scintillation camera. Secondly, to provide a scintillation camera system to increase the rate of acceptance of radioactive events to contribute to the positional information obtainable from a known radiation source without sacrificing spatial resolution. Thirdly to reduce the scanning time without loss of image clarity. The system described comprises a scintillation camera detector, means for moving this in orbit about a cranial-caudal axis relative to a patient and a collimator having septa defining apertures such that gamma rays perpendicular to the axis are admitted with high spatial resolution, parallel to the axis with low resolution. The septa may be made of strips of lead. Detailed descriptions are given. (U.K.)

  5. Collimated trans-axial tomographic scintillation camera

    International Nuclear Information System (INIS)

    1980-01-01

    The principal problem in trans-axial tomographic radioisotope scanning is the length of time required to obtain meaningful data. Patient movement and radioisotope migration during the scanning period can cause distortion of the image. The object of this invention is to reduce the scanning time without degrading the images obtained. A system is described in which a scintillation camera detector is moved to an orbit about the cranial-caudal axis relative to the patient. A collimator is used in which lead septa are arranged so as to admit gamma rays travelling perpendicular to this axis with high spatial resolution and those travelling in the direction of the axis with low spatial resolution, thus increasing the rate of acceptance of radioactive events to contribute to the positional information obtainable without sacrificing spatial resolution. (author)

  6. Axial flux data for fuel measurement

    Energy Technology Data Exchange (ETDEWEB)

    Popovich, R.P.

    1964-02-11

    A survey of the PITA-18 nonpoisonous spline program was conducted in conjunction with a study to determine the best method of eliminating the variability of axial flux on the fuel performance parameter, q. The results of this survey and the conclusions reached in the rupture coefficient study were found to be inter-dependent such that both are presented in this report. The data from the PITA-18 nonpoisonous spline program, as received, is the output of the NOLA-2 computer program. One quantity of interest is the rupture potential relative to a cosine, commonly referred to as the relative rupture potential. As programmed, the relative rupture potential, which was derived by applying the rupture model to individual fuel elements, might be expected to vary linearly with the rupture rate. The use of the relative rupture potential was studied over the period of July 1962 through December 1963. The results of this study are presented.

  7. Composite Axial Flow Propulsor for Small Aircraft

    Directory of Open Access Journals (Sweden)

    R. Poul

    2005-01-01

    Full Text Available This work focuses on the design of an axial flow ducted fan driven by a reciprocating engine. The solution minimizes the turbulization of the flow around the aircraft. The fan has a rotor - stator configuration. Due to the need for low weight of the fan, a carbon/epoxy composite material was chosen for the blades and the driving shaft.The fan is designed for optimal isentropic efficiency and free vortex flow. A stress analysis of the rotor blade was performed using the Finite Element  Method. The skin of the blade is calculated as a laminate and the foam core as a solid. A static and dynamic analysis were made. The RTM technology is compared with other technologies and is described in detail. 

  8. CT findings after normal and unsuccessful functional endoscopic sinus surgery; Ruolod della tomografia computerizzata dopo chirurgia funzionale dei seni paranasali: rilievi normali e valutazioni degli insuccessi chirurgici

    Energy Technology Data Exchange (ETDEWEB)

    Scribano, E.; Ascenti, G.; Bellinvia, A.; Mazziotti, S.; Lamberto, S. [Messina Univ., Messina (Italy). Ist. di Scienze Radiologiche; Cascio, F. [Messina Univ., Messina (Italy). Ist. di Otorinolaringoiatria

    1999-09-01

    The paper investigates the functional endoscopic sinus surgery with the Messer-linger's technique which treats benign or inflammatory diseases of paranasal sinuses resistant to medical therapy. The goal of this type of surgery is to open the obstructed sinus ostia and restore normal aeration and mucociliary clearance. The computerized tomography permits an accurate assessment of extension and results of functional endoscopic sinus surgery. [Italian] L'articolo discute l'uso della tecnica di Messerklinger nella chirurgia funzionale endoscopica dei seni paranasali per il trattamento delle malattie benigne e delle infiammazioni croniche. Essa disostruisce gli osti sinusali ripristinando la normale areazione e la pulizia mucociliare. La tomografia computerizzata consente di valutare l'estensione e i risultati del trattamento chirurgico funzionale, soprattutto nel caso di insuccesso terapeutico, rilevando malattia nasosinusale ricorrente e-o recidiva.

  9. Sarcoidose pulmonar: achados na tomografia computadorizada de alta resolução Pulmonary sarcoidosis: high-resolution computed tomography findings

    Directory of Open Access Journals (Sweden)

    Bruno Barcelos da Nóbrega

    2005-06-01

    Full Text Available A sarcoidose é uma doença sistêmica de causa indeterminada, caracterizada por granulomas não-caseosos. Embora possa afetar qualquer órgão, esta doença tem sua morbi-mortalidade relacionada principalmente ao acometimento pulmonar, presente em 80% a 90% dos pacientes. Este artigo ilustra as principais manifestações pulmonares da sarcoidose na tomografia computadorizada de alta resolução, incluindo as formas típicas e atípicas.Sarcoidosis is a systemic disease of unknown etiology, characterized by noncaseating granulomas. Although it may affect any organ, morbidity and mortality are most commonly related to pulmonary involvement, which is found in 80-90% of patients. This study illustrates the principal manifestations of sarcoidosis seen in high-resolution computed tomography scans, including typical as well as atypical forms.

  10. Seguimento de portadores de coriorretinopatia serosa central por meio da tomografia de coerência óptica Evaluation of central serous chorioretinopathy with optical coherence tomography

    Directory of Open Access Journals (Sweden)

    Otacílio de Oliveira Maia Júnior

    2006-04-01

    Full Text Available OBJETIVO: Avaliar a tomografia de coerência óptica como método objetivo de diagnóstico e de seguimento da coriorretinopatia serosa central. MÉTODOS: Estudo observacional descritivo de 16 (dezesseis olhos de portadores de coriorretinopatia serosa central unilateral, em fase aguda. Estes pacientes foram submetidos à medida da acuidade visual e a exame oftalmológico completo, incluindo biomicroscopia da mácula, angiofluoresceinografia e tomografia de coerência óptica. Nenhum dos pacientes foi submetido a qualquer tipo de tratamento. RESULTADO: Dos 16 casos consecutivos de coriorretinopatia serosa central, 12 pacientes completaram o seguimento até a resolução da doença. A idade variou entre 27 e 50 anos, com média de 38,9 anos. A predominância foi do sexo masculino. Na tomografia de coerência óptica, o descolamento da retina neurossensorial foi observado em todos os casos e 33,3% dos pacientes apresentaram descolamento do epitélio pigmentado da retina. Houve diferença significativa em todas as variáveis estudadas, constatando melhora na acuidade visual, diminuição na espessura e no volume macular na resolução da doença. CONCLUSÃO: Tomografia de coerência óptica mostrou boa eficácia para detectar e quantificar alterações maculares em olhos com coriorretinopatia serosa central, podendo ser útil em avaliações clínicas na fase aguda e na resolução da doença.PURPOSE: To evaluate optical coherence tomography as an objective diagnostic and follow-up method for central serous chorioretinopathy. METHODS: Observational descriptive study of 16 (sixteen eyes of 16 patients with unilateral acute central serous chorioretinopathy. These patients had their visual acuity measured and complete ophthalmological examination was performed, including macular slit lamp examination, angiofluoresceinography and optical coherence tomography. No treatment was given to any patient. RESULTS: Of the 16 central serous chorioretinopathy eyes

  11. CT diagnosis of subphrenic abscess after splenectomy for trauma; Ruolo della tomografia computerizzata nella valutazione degli ascessi subfrenici dopo splenectomia post-traumatica

    Energy Technology Data Exchange (ETDEWEB)

    Salzano, A. [Ospedale Loreto-Mare, Neaples (IT). Serv. di Radiologia] [and others

    1999-09-01

    The paper studies subphrenic inflammatory abscesses and splenic fluid collections after splenectomy for trauma. These complications may appear early or late postoperatively; they are easily demonstrated with computerized tomography, which permits accurate spatial assessment of the lesions and appropriate treatment with percutaneous drainage. It has been also investigates the diagnostic accuracy of the CT in subphrenic inflammatory conditions after emergency splenectomy for traumatic spleen rupture and found that CT is a precious tool for rapid and easy diagnosis and follow-up of subphrenic abscesses treated with percutaneous drainage. [Italian] Scopo del lavoro e' di valutare il ruolo della tomografia computerizzata nelle flogrosi subfreniche secondarie a splenectomia d'urgenza per rottura traumatica della milza, documentando come tale metodica risulti accurata nel diagnosticare e monitorare in modo semplice e rapido l'evoluzione e il controllo degli ascessi subfrenici trattati con drenaggio percutaneo.

  12. Estimation of ocular volume from axial length.

    Science.gov (United States)

    Nagra, Manbir; Gilmartin, Bernard; Logan, Nicola S

    2014-12-01

    To determine which biometric parameters provide optimum predictive power for ocular volume. Sixty-seven adult subjects were scanned with a Siemens 3-T MRI scanner. Mean spherical error (MSE) (D) was measured with a Shin-Nippon autorefractor and a Zeiss IOLMaster used to measure (mm) axial length (AL), anterior chamber depth (ACD) and corneal radius (CR). Total ocular volume (TOV) was calculated from T2-weighted MRIs (voxel size 1.0 mm(3)) using an automatic voxel counting and shading algorithm. Each MR slice was subsequently edited manually in the axial, sagittal and coronal plane, the latter enabling location of the posterior pole of the crystalline lens and partitioning of TOV into anterior (AV) and posterior volume (PV) regions. Mean values (±SD) for MSE (D), AL (mm), ACD (mm) and CR (mm) were -2.62±3.83, 24.51±1.47, 3.55±0.34 and 7.75±0.28, respectively. Mean values (±SD) for TOV, AV and PV (mm(3)) were 8168.21±1141.86, 1099.40±139.24 and 7068.82±1134.05, respectively. TOV showed significant correlation with MSE, AL, PV (all p<0.001), CR (p=0.043) and ACD (p=0.024). Bar CR, the correlations were shown to be wholly attributable to variation in PV. Multiple linear regression indicated that the combination of AL and CR provided optimum R(2) values of 79.4% for TOV. Clinically useful estimations of ocular volume can be obtained from measurement of AL and CR. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  13. Paracoccidioidomicose pulmonar: relato de caso clínico com aspetos em tomografia computorizada de alta resolução

    Directory of Open Access Journals (Sweden)

    M. Armas

    2012-07-01

    Full Text Available Resumo: A Paracoccidioidomicose é uma micose sistémica endémica nas áreas rurais da América Latina, uma fonte importante de imigrantes e destino de emigração e turismo europeu, a maioria dos casos ocorrendo no Brasil, Argentina, Venezuela e Colômbia. Os autores descrevem o caso clínico de um paciente com 43 anos, anteriormente emigrado na Venezuela e residente em Portugal há 8 anos, que se apresenta com lesão cutânea isolada. Embora sem queixas relevantes do foro respiratório, apresentava extensas lesões do parênquima pulmonar caracterizadas por tomografia computorizada de alta resolução (TCAR. Foi realizada biópsia da lesão cutânea e exame micológico da expetoração que revelaram infeção por Paracoccidioides brasiliensis (PB. Abstract: Paracoccidioidomycosis is a systemic mycosis which is endemic in rural areas of Latin America, an important European source of immigrants and a growing European touristic destination as well, with most cases occurring in Brazil, Argentina, Venezuela and Colombia. The authors report a case of a 43 year old man who previously worked in Venezuela and is living in Portugal for 8 years, presenting with a single cutaneous lesion. Despite the absence of valuable respiratory complaints, severe lung damage was found with high-resolution computed tomography (HRCT. Biopsy of the cutaneous lesion and mycologic sputum examination were performed revealing Paracoccidioides brasiliensis infection. Palavras-chave: Paracoccidioidomicose, Paracoccidioides brasiliensis, Fibrose pulmonar, Tomografia computorizada de alta resolução, Keywords: Paracoccidioidomycosis, Paracoccidioides brasiliensis, Pulmonary fibrosis, High-resolution computed tomography

  14. Alterações difusas da traquéia: aspectos na tomografia computadorizada Diffuse abnormalities of the trachea: computed tomography findings

    Directory of Open Access Journals (Sweden)

    Edson Marchiori

    2008-01-01

    Full Text Available O objetivo deste ensaio pictórico foi apresentar as principais alterações tomográficas observadas em doenças que acometem a traquéia de forma difusa. As doenças estudadas foram amiloidose, traqueobroncopatia osteocondroplástica, traqueobroncomegalia, papilomatose laringo-traqueo-brônquica, linfoma, neurofibromatose, policondrite recidivante, granulomatose de Wegener, tuberculose, paracoccidioidomicose e traqueobroncomalácia. O principal aspecto observado na tomografia computadorizada foi o espessamento das paredes traqueais, com ou sem nodulações, calcificações parietais ou comprometimento da parede posterior. Embora a tomografia computadorizada permita a detecção e a caracterização das doenças das vias aéreas centrais, e a correlação com os dados clínicos reduza as possibilidades diagnósticas, a broncoscopia com biópsia continua sendo o procedimento mais importante no diagnóstico das lesões difusas da traquéia.The aim of this pictorial essay was to present the main computed tomography findings seen in diffuse diseases of the trachea. The diseases studied included amyloidosis, tracheobronchopathia osteochondroplastica, tracheobronchomegaly, laryngotracheobronchial papillomatosis, lymphoma, neurofibromatosis, relapsing polychondritis, Wegener's granulomatosis, tuberculosis, paracoccidioidomycosis, and tracheobronchomalacia. The most common computed tomography finding was thickening of the walls of the trachea, with or without nodules, parietal calcifications, or involvement of the posterior wall. Although computed tomography allows the detection and characterization of diseases of the central airways, and the correlation with clinical data reduces the diagnostic possibilities, bronchoscopy with biopsy remains the most useful procedure for the diagnosis of diffuse lesions of the trachea.

  15. Tomografia computadorizada em pacientes portadores de neurocisticercose com hipertensão intracraniana por hidrocefalia obstrutiva: comparação com ventriculografia com Dimer-X

    Directory of Open Access Journals (Sweden)

    Benedicto Oscar Colli

    1984-06-01

    Full Text Available Estudo das alterações observadas nas tomografias computadorizadas (TCs de 16 casos de neurocisticercose, com hipertensão intracraniana por hidrocefalia. Todos os casos foram submetidos a radiografias simples do crânio e 12, à ventriculografia com Dimer-X. Nas radiografias simples foram observados sinais de hipertensão intracraniana em 7, calcificações em um, e d foram normais. A TC mostrou parênquima cerebral normal em 9 casos e nos 7 restantes áreas hipodensas arredondadas de tamanho variado, com ou sem retenção de contraste na periferia, e/ou calcificações esparsas no parenquima. Hidrocefalia foi a única alteração observada no sistema ventricular nos casos em que o exame foi realizado previamente à derivação do LCR. As ventriculografias foram analisadas em trabalho anterior e permitiram localizar e determinar as características da obstrução e a presença de massas ocupando espaço dentro dos ventrículos. A comparação das ventriculografias e TCs realizadas na mesma época evidenciou que a primeira fornece melhores informações sobre o sistema ventricular mas, por outro lado, a tomografia fornece informações adicionais sobre o parênquima cerebral. A TC e a ventriculografia são exames que se completam na avaliação e no diagnóstico destes pacientes.

  16. Axial and coronal orientation of subaxial cervical zygapophysial joints and their effect on axial rotation and lateral bending.

    Science.gov (United States)

    Hsu, Wen-Hsing; Benzel, Edward C; Chen, Tzu-Yung; Chen, Yao-Liang

    2008-10-15

    Computerized tomography and image processing methodologies were used to analyze the axial and coronal orientation of cervical zygapophysial joints in asymptomatic adults. Surface motions of axial rotation and lateral bending were simulated. The study was designed to obtain the normal distribution and variation of facet orientation (FO) in axial and coronal planes to investigate factors affecting FO and to study the effects of FO on axial rotation and lateral bending. The FO of the subaxial cervical spine is usually evaluated in the sagittal plane. Cervical spine axial and coronal FO is usually considered to be horizontal. The literature reveals no statistical data for axial or coronal FO. Serial thin-sliced computed tomography scans of the cervical spine in asymptomatic adults were input into Image J, National Institutes of Health, image processing software. Bilateral zygapophysial joint angles from C2-C3 to C6-C7 were measured in the axial and coronal planes and collected from 100 subjects. The effect of gender, age, and correlation was analyzed. The surface motions of axial rotation and lateral bending were simulated in Abaqus CAE 6.5. Mathematical facet contact and range of motion were computed. The FO was widely distributed at each level. Gender had no significant association with FO. Age affected FO at most levels. Axial and coronal FO were significantly correlated. The zygapophysial joint of internally rotated/inverted FO contacted more perpendicularly to each other, and mathematical range of motion was smaller. The axial or coronal FO of the subaxial cervical spine was found with more variability. Age was significantly related to FO. Geometrically, internally rotated/inverted FO of axial rotation/lateral bending was morerestricted. The extent of axial rotation and lateral bending was correlated with each other.

  17. Avaliação da epífora de cães usando dacriocistografia e tomografia computadorizada

    Directory of Open Access Journals (Sweden)

    Nivea M.G. Vieira

    2015-12-01

    Full Text Available Resumo: A avaliação da epífora pode ser feita por exames clínicos, testes de excreção lacrimal, exames contrastados, como avaliação radiológica e estudo tomográfico; estes dois últimos permitem análise minuciosa das estruturas. O presente estudo teve como objetivo avaliar a via lacrimal excretora com uso de radiografia e tomografia computadorizada contrastadas, feitas em animais com epífora, comparando-se com animais sadios, sem essa afecção. Foram utilizados 20 cães, de raças e pelagens variadas, machos e fêmeas, com peso de 1 a 20 kg, com 0,7 a 8 anos de idade, apresentando epífora (grupo epífora - GE. Como grupo de controle (GC, foram utilizados 15 cães, sem alterações clínicas de drenagem do sistema lacrimonasal de raças e pelagens variadas, machos e fêmeas, pesando 1 a 20 kg, com 0,7 a 8 anos. Foi proposta a divisão do sistema de drenagem lacrimal em quatro regiões. Na região 1, o GE teve 29 (76,3% animais com dilatação visibilizada pelo R-X e 32 (84,2% pela TC; no GC, 4 (12,5% no R-X e 1 (3,1% na TC demonstraram dilatação. Na região 3, 13 (34,2% cães evidenciaram dilatação do DLN no R-X e 14 (36,8% na TC; e 21 (55,3% comunicação do ducto lacrimonasal com o seio nasal pelo R-X e 28 (73,7% pela TC. Já no GC, 15 (46,9% pelo R-X e 22 (68,7% pela TC possuíam comunicação do ducto lacrimonasal com o seio nasal. Concluiu-se que: dilatações também podem ser observadas em alguns cães sem sinal clínico da afecção; comunicação do ducto lacrimonasal com o seio nasal não indica alteração causadora de epífora, pois está presente em animais com e sem afecção; os dados do presente estudo confirmam que o exame DCG por si pode dar importantes informações, de forma semelhante à TC, devendo-se recorrer à ela apenas quando houver dúvidas sobre lesões ósseas, fraturas e corpos estranhos não detectados pelo primeiro.

  18. Equation of motion for the axial gravitational superfield

    International Nuclear Information System (INIS)

    Ogievetsky, V.; Sokatchev, E.

    1980-01-01

    Transformation properties of the axial supergravitational field variants are investigated. The equation of motion for the axial gravitational superfield is derived by direct variation of the N = 1 supergravity action. The left-hand side of this equation is a component of the torsion tensor, and the right-hand side is the supercurrent. The question about the cosmological term in supergravity is discussed

  19. Radiation dose to the patient and the radiologist while performing on chest computed tomography: a program of early diagnosis of lung cancer, biopsy and treatment simulation guided radiation oncologist breast cancer; Dosis de radiacion al paciente y al radiologo durante la realizacion de tomografia computarizada en torax: progrma de diagnostico precoz del cancer de pulmon, biopsia guiada y simulacion del tratamiento oncologo radioterapico del cancer de mama

    Energy Technology Data Exchange (ETDEWEB)

    Pastor Sanchis, V.; Martinez Sanchez, J. M.; Palma Copete, J. D.; Crispin Contreras, V.; Casal Zamorano, E.; Dolores Alemany, V. de los; Gonzalez Perez, V.; Gimeno Olmo, J.; Guardino de la Flor, C.

    2011-07-01

    In this paper we determine the equivalent dose received by the operator and patient lung biopsies using thermoluminescence dosimeters, are established recommendations that this dose is as low as possible. It also reviews the acquisition protocols in both CT scans in early diagnosis program cited as the acquisition of CT for treatment planning dosimetric radiation oncologist in breast cancer.

  20. Avaliação da expansão rápida da maxila por meio da tomografia computadorizada: relato de um caso Computed tomography evaluation of rapid maxillary expansion: a case report

    Directory of Open Access Journals (Sweden)

    Daniela Gamba Garib

    2005-08-01

    Full Text Available Este trabalho descreve os efeitos dentoesqueléticos e periodontais da expansão rápida da maxila (ERM, avaliados por meio da tomografia computadorizada (TC, em uma jovem de 11,6 anos de idade com má oclusão de Classe I e mordida cruzada posterior unilateral funcional. Durante a fase ativa da ERM, o expansor dentossuportado com parafuso Hyrax foi ativado 7mm. A paciente submeteu-se ao exame de TC helicoidal, antes da expansão e após a remoção do aparelho expansor, findo o período de três meses de contenção. Realizaram-se cortes axiais, de um milímetro de espessura, paralelamente ao plano palatino, englobando as regiões dentoalveolar e basal da maxila, até o terço inferior da cavidade nasal. Utilizando-se o recurso de reconstruções multiplanares, mensuraram-se pelo método computadorizado: as dimensões transversas maxilares, a inclinação dos dentes posteriores, a espessura das tábuas ósseas vestibular e lingual, e o nível da crista óssea alveolar vestibular. A expansão rápida da maaxila ocasionou um significante aumento transverso em todas as regiões aferidas, com magnitude decrescente do arco dentário para a base óssea. Os dentes posteriores foram movimentados para vestibular, com um componente de inclinação e translação associados. Tal efeito ortodôntico ocasionou uma redução na espessura da tábua óssea vestibular, e um concomitante aumento na espessura da tábua óssea lingual. Após a expansão, observou-se o desenvolvimento de deiscências ósseas por vestibular dos dentes de ancoragem.This paper presents a computed tomography (CT evaluation of rapid maxillary expansion dentoskeletal and periodontal effects, in a 11.6 year-old girl presenting Class I malocclusion with posterior unilateral crossbite. The tooth-borne expander with Hyrax screw was activated 7-mm. The patient was submitted to helicoidal CT scan before expansion and after the three-month retention period when the expander was removed. Axial

  1. Bi-axial quartz as a stress indicator

    Science.gov (United States)

    Starkey, John

    2000-03-01

    Experiments confirm that stress causes quartz to become biaxial with the optical axial plane parallel to the direction of maximum applied stress. Five tectonites were studied for which published data indicate strong patterns of preferred orientation of quartz. Conoscopic investigation, using an optical universal stage, reveals that the quartz in these rocks is biaxial with the 2V as large as 22°. The optic axial planes display strong patterns of preferred orientation. In the natural tectonites the maximum stress directions deduced from the orientations of the optical axial planes cannot be correlated with the supposed tectonic framework responsible for the quartz orientation fabric. The ease with which quartz can be made biaxial experimentally suggests that the orientation of the optic axial planes may be sensitive to tectonic events which affected the rocks subsequent to the development of the quartz orientation fabrics. The analysis of the orientation of optic axial planes in biaxial quartz may provide a tool for the investigation of neotectonics.

  2. Relation between axial length and ocular parameters

    Directory of Open Access Journals (Sweden)

    Xue-Qiu Yang

    2013-09-01

    Full Text Available AIM: To investigatethe relation between axial length(AL, age and ocular parameters.METHODS: A total of 360 subjects(360 eyeswith emmetropia or myopia were recruited. Refraction, center corneal thickness(CCT, AL, intraocular pressure(IOPwere measured by automatic-refractor, Pachymeter, A-mode ultrasound and non-contact tonometer, respectively. Corneal curvature(CC, anterior chamber depth(ACDand white-to-white distance(WWDwere measured by Orbscan II. Three dimensional frequency domain coherent optical tomography(3D-OCTwas used to examine the retinal nerve fiber layer thickness(RNFLT. The Pearson correlation coefficient(rand multiple regression analysis were performed to evaluate the relationship between AL, age and ocular parameters.RESULTS: The average AL was 24.15±1.26mm. With elongation of the AL, spherical equivalent(SE(r=-0.742,Pr=-0.395, Pr=-0.374, Pr=0.411, Pr=0.099, P=0.060and WWD(r=0.061, P=0.252. There was also a significant correlation between AL and age(P=0.001, SE(PPPCONCLUSION: In longer eyes, there is a tendency toward myopia, a flatter cornea, a deeper ACD and a thinner RNFLT. Age is an influencing factor for the AL as well.

  3. Nucleon axial coupling from Lattice QCD

    Science.gov (United States)

    Cheng Chang, Chia; Nicholson, Amy; Rinaldi, Enrico; Berkowitz, Evan; Garron, Nicolas; Brantley, David; Monge-Camacho, Henry; Monahan, Chris; Bouchard, Chris; Clark, M. A.; Joó, Bálint; Kurth, Thorsten; Orginos, Kostas; Vranas, Pavlos; Walker-Loud, André

    2018-03-01

    We present state-of-the-art results from a lattice QCD calculation of the nucleon axial coupling, gA, using Möbius Domain-Wall fermions solved on the dynamical Nf = 2 + 1 + 1 HISQ ensembles after they are smeared using the gradient-flow algorithm. Relevant three-point correlation functions are calculated using a method inspired by the Feynman-Hellmann theorem, and demonstrate significant improvement in signal for fixed stochastic samples. The calculation is performed at five pion masses of mπ {400, 350, 310, 220, 130} MeV, three lattice spacings of a {0.15, 0.12, 0.09} fm, and we do a dedicated volume study with mπL {3.22, 4.29, 5.36}. Control over all relevant sources of systematic uncertainty are demonstrated and quantified. We achieve a preliminary value of gA = 1.285(17), with a relative uncertainty of 1.33%.

  4. Axial sheath dynamics in a plasma focus

    International Nuclear Information System (INIS)

    Soliman, H.M.; El-Khalafawy, T.A.; Masoud, M.M.

    1990-01-01

    This paper presents the result of investigation with a 10 kJ Mather type plasma focus. It is operated in hydrogen gas at ambient pressure of 0.15--1 torr and charging voltage of 8--11 kV. Radial distribution of the current sheath density with axial distance has been estimated. Plasma rotation in the expansion chamber in the absence of external magnetic field has been detected. A plasma flare from the plasma focus region propagating in the radial direction has been observed. Streak photography shows two plasma streams flowing simultaneously out of the muzzle. The mean energy of the electron beam ejected from the pinch region of the focused plasma, was measured by retarding field analyzer to be 0.32 keV. The electron temperature of the plasma focus at peak compression was determined by measuring the X-ray intensity as a function of absorber thickness at a distance of 62 cm from the focus. The electron temperature has been found to 3 keV

  5. Nitinol stent design - understanding axial buckling.

    Science.gov (United States)

    McGrath, D J; O Brien, B; Bruzzi, M; McHugh, P E

    2014-12-01

    Nitinol׳s superelastic properties permit self-expanding stents to be crimped without plastic deformation, but its nonlinear properties can contribute towards stent buckling. This study investigates the axial buckling of a prototype tracheobronchial nitinol stent design during crimping, with the objective of eliminating buckling from the design. To capture the stent buckling mechanism a computational model of a radial force test is simulated, where small geometric defects are introduced to remove symmetry and allow buckling to occur. With the buckling mechanism ascertained, a sensitivity study is carried out to examine the effect that the transitional plateau region of the nitinol loading curve has on stent stability. Results of this analysis are then used to redesign the stent and remove buckling. It is found that the transitional plateau region can have a significant effect on the stability of a stent during crimping, and by reducing the amount of transitional material within the stent hinges during loading the stability of a nitinol stent can be increased. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Conservative axial burnup distributions for actinide-only burnup credit

    International Nuclear Information System (INIS)

    Kang, C.; Lancaster, D.

    1997-11-01

    Unlike the fresh fuel approach, which assumes the initial isotopic compositions for criticality analyses, any burnup credit methodology must address the proper treatment of axial burnup distributions. A straightforward way of treating a given axial burnup distribution is to segment the fuel assembly into multiple meshes and to model each burnup mesh with the corresponding isotopic compositions. Although this approach represents a significant increase in modeling efforts compared to the uniform average burnup approach, it can adequately determine the reactivity effect of the axial burnup distribution. A major consideration is what axial burnup distributions are appropriate for use in light of many possible distributions depending on core operating conditions and histories. This paper summarizes criticality analyses performed to determine conservative axial burnup distributions. The conservative axial burnup distributions presented in this paper are included in the Topical Report on Actinide-Only Burnup Credit for Pressurized Water Reactor Spent Nuclear Fuel Packages, Revision 1 submitted in May 1997 by the US Department of Energy (DOE) to the US Nuclear Regulatory Commission (NRC). When approved by NRC, the conservative axial burnup distributions may be used to model PWR spent nuclear fuel for the purpose of gaining actinide only burnup credit

  7. Axial elongation following prolonged near work in myopes and emmetropes.

    Science.gov (United States)

    Woodman, Emily C; Read, Scott A; Collins, Michael J; Hegarty, Katherine J; Priddle, Scott B; Smith, Josephine M; Perro, Judd V

    2011-05-01

    To investigate the influence of a period of sustained near work upon axial length in groups of emmetropes (EMM) and myopes. Forty young adult subjects (20 myopes and 20 emmetropes) were recruited for the study. Myopes were further classified as early onset (EOM), late onset (LOM), stable (SM) or progressing (PM) subgroups. Axial length was measured with the IOLMaster instrument before, immediately after and then again 10 min after a continuous 30 min near task of 5 D accommodation demand. Measures of distance objective refraction were also collected. Significant changes in axial length were observed immediately following the near task. EOM axial length elongated on average by 0.027±0.021 mm, LOM by 0.014±0.020 mm, EMM by 0.010±0.015 mm, PM by 0.031±0.022 mm and SM by 0.014±0.018 mm. At the conclusion of the 10 min regression period, axial length measures were not significantly different from baseline values. Axial elongation was observed following a prolonged near task. Both EOM and PM groups showed increases in axial length that were significantly greater than emmetropes.

  8. Dispositivos de asistencia ventricular de tipo axial

    Directory of Open Access Journals (Sweden)

    Albert Miralles Cassina

    2009-04-01

    Full Text Available El uso de dispositivos de asistencia ventricular se ha ido extendiendo en las últimas décadas. La mejora de los resultados ha ido acompañada del diseño de nuevos aparatos más pequeños y eficientes como son las bombas de flujo axial. las características técnicas básicas de estos dispositivos se hallan en la generación de un flujo continuo unidireccional conseguido mediante sistemas de turbina que obtienen su alimentación de una fuente eléctrica. Las ventajas principales de estos dispositivos son: su facilidad de implantación por su tamaño reducido, su prolongada durabilidad gracias a su sencillo diseño y su eficiencia energética al utilizar energía eléctrica. Su utilidad se ha podido demostrar en diferentes indicaciones de asistencia circulatoria mecánica, como en el caso de puente al trasplante o dispositivo de recuperación miocárdica, si bien donde radica más interés es en su uso como sistemas de asistencia circulatoria mecánica definitiva. Existe una variedad de modelos de diversos diseños. Son dispositivos que permiten soporte normalmente univentricular izquierdo, que se implantan en el tórax con cánula de entrada a nivel ventricular y cánula de salida a nivel aórtico. En este artículo se efectúa una descripción de los principales sistemas disponibles en la actualidad, comentando las características técnicas, ventajas e inconvenientes y un resumen de la experiencia existente.

  9. El uso precoz de la tomografía computarizada en el manejo de la diverticulitis aguda Early use of CT in the management of acute diverticulitis of the colon

    Directory of Open Access Journals (Sweden)

    J. Martín Arévalo

    2007-06-01

    Full Text Available Objetivo: valorar el uso precoz de la tomografía computarizada (TC para el diagnóstico, estadificación y manejo de la diverticulitis aguda. Material y métodos: realizamos un estudio prospectivo de 102 pacientes con el diagnóstico clínico de diverticulitis aguda de colon izquierdo. La diverticulitis aguda fue inicialmente dividida en tres estadios. Los pacientes fueron reestadiados en los estadios I, IIa, IIb y III de acuerdo a los hallazgos encontrados en la TC. El diagnóstico se confirmó después intraoperatoriamente, por colonoscopia o estudio con bario. Resultados: fueron incluidos 102 pacientes (52 mujeres y 50 hombres con una edad media de 59,4 (DS ± 14,96. En 84 (82,35% pacientes con el diagnóstico clínico de diverticulitis aguda se confirmó este diagnóstico con un error diagnóstico del 17,65% (n = 18. La diverticulitis aguda se diagnosticó con la TC en el 84,3% (n = 86. La TC tuvo una sensibilidad del 100% y especificidad del 88,9%. La TC cambió la estadificación clínica en un 38% debido a una infraestadificación del 13% y una sobreestadificación del 25%, que llega al 60 y al 50% en los estadios clínicos II y III, respectivamente. La reclasificación o reestadificación de los pacientes de acuerdo con los hallazgos en la TC tiene una consecuencia importante en la indicación quirúrgica. Conclusiones: la estadificación clínica precoz de la diverticulitis con la TC evita errores de diagnóstico clínico en el 17,65%. La TC modifica la estadificación clínica de severidad en el 38% evitando la cirugía innecesaria y el retraso en el tratamiento quirúrgico.Objectives: to assess the early use of CT for the diagnosis, staging, and management of acute diverticulitis. Materials and methods: a prospective study of 102 patients with a clinical diagnosis of acute diverticulitis of the left colon. Acute diverticulitis was initially divided into 3 clinical stages. Patients were restaged according to CT findings into stages I

  10. Radial loads and axial thrusts on centrifugal pumps

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    The proceedings of a seminar organised by the Power Industries Division of the IMechE are presented in this text. Complete contents: Review of parameters influencing hydraulic forces on centrifugal impellers; The effect of fluid forces at various operation conditions on the vibrations of vertical turbine pumps; A review of the pump rotor axial equilibrium problem - some case studies; Dynamic hydraulic loading on a centrifugal pump impeller; Experimental research on axial thrust loads of double suction centrifugal pumps; A comparison of pressure distribution and radial loads on centrifugal pumps; A theoretical and experimental investigation of axial thrusts within a multi-stage centrifugal pump

  11. Measurement for cobalt target activity and its axial distribution

    International Nuclear Information System (INIS)

    Li Xingyuan; Chen Zigen.

    1985-01-01

    Cobalt target activity and its axial distribution are measured in process of producing radioactive isotopes 60 Co by irradiation in HFETR. Cobalt target activity is obtained with measured data at 3.60 m and 4.60 m, relative axial distribution of cobalt target activity is obtained with one at 30 cm, and axial distribution of cobalt target activity(or specific activity) is obtained with both of data. The difference between this specific activity and measured result for 60 Co teletherapy sources in the end is less than +- 5%

  12. Axial weak currents in the Wess-Zumino term

    International Nuclear Information System (INIS)

    Fujikawa, Kazuo.

    1985-03-01

    The conventional axial gauging of the Wess-Zumino term leads to the results which do not necessarily agree with the expectations on the basis of quark level Ward-Takahashi identities. This discrepancy arises from the fact that the quark level anomalous identities reflect the short distance structure of QCD, whereas the gauging of the Wess-Zumino term reflects the axial symmetry in the spontaneously broken chiral phase. The low energy theorem for axial weak fields is not sharply defined, in contrast to the case of vector fields where no such complications arise. (author)

  13. The Design Method of Axial Flow Runners Focusing on Axial Flow Velocity Uniformization and Its Application to an Ultra-Small Axial Flow Hydraulic Turbine

    Directory of Open Access Journals (Sweden)

    Yasuyuki Nishi

    2016-01-01

    Full Text Available We proposed a portable and ultra-small axial flow hydraulic turbine that can generate electric power comparatively easily using the low head of open channels such as existing pipe conduits or small rivers. In addition, we proposed a simple design method for axial flow runners in combination with the conventional one-dimensional design method and the design method of axial flow velocity uniformization, with the support of three-dimensional flow analysis. Applying our design method to the runner of an ultra-small axial flow hydraulic turbine, the performance and internal flow of the designed runner were investigated using CFD analysis and experiment (performance test and PIV measurement. As a result, the runners designed with our design method were significantly improved in turbine efficiency compared to the original runner. Specifically, in the experiment, a new design of the runner achieved a turbine efficiency of 0.768. This reason was that the axial component of absolute velocity of the new design of the runner was relatively uniform at the runner outlet in comparison with that of the original runner, and as a result, the negative rotational flow was improved. Thus, the validity of our design method has been verified.

  14. Consistency of ocular coherence tomography fast macular thickness mapping in diabetic diffuse macular edema Consistência da tomografia de coerência óptica no edema macular difuso diabético

    Directory of Open Access Journals (Sweden)

    Fábio Petersen Saraiva

    2007-01-01

    Full Text Available OBJECTIVES: To investigate optical coherence tomography consistency on foveal thickness, foveal volume, and macular volume measurements in patients with and without diffuse diabetic macular edema. INTRODUCTION: Optical coherence tomography represents an objective technique that provides cross-sectional tomographs of retinal structure in vivo. However, it is expected that poor fixation ability, as seen in diabetic macular edema, could alter its results. Several authors have discussed the reproducibility of optical coherence tomography, but only a few have addressed the topic with respect to diabetic maculopathy. METHODS: The study recruited diabetic patients without clinically evident retinopathy (control group and with diffuse macular edema (case group. Only one eye of each patient was evaluated. Five consecutive fast macular scans were taken using Ocular Coherence Tomography 3; the 6 mm macular map was chosen. The consistency in measurements of foveal thickness, foveal volume, and total macular volume for both groups was evaluated using the Pearson's coefficient of variation. The T-test for independent samples was used in order to compare measurements of both groups. RESULTS: Each group consisted of 20 patients. All measurements had a coefficient of variation less than 10%. The most consistent parameter for both groups was the total macular volume. DISCUSSION: Consistency in measurement is a mainstay of any test. A test is unreliable if its measurements can not be correctly repeated. We found a good index of consistency, even considering patients with an unstable gaze. CONCLUSIONS: Optical coherence tomography is a consistent method for diabetic subjects with diffuse macular edema.OBJETIVOS: Investigar a consistência das medidas de espessura foveal, volume foveal e volume macular total feitas pela tomografia de coerência óptica em pacientes com e sem edema macular difuso diabético. INTRODUÇÃO: A tomografia de coerência óptica é uma t

  15. The Nonradiographic Axial Spondyloarthritis, the Radiographic Axial Spondyloarthritis, and Ankylosing Spondylitis: The Tangled Skein of Rheumatology

    Science.gov (United States)

    Rawat, Roopa; Agrawal, Neha; Patil, Nilesh S.

    2017-01-01

    Since 1984 the diagnosis of ankylosing spondylitis (AS) has been based upon the modified New York (mNY) criteria with mandatory presence of radiographic sacroiliitis, without which the diagnosis is not tenable. However, it may take years or decades for radiographic sacroiliitis to develop delaying the diagnosis for long periods. It did not matter in the past because no effective treatment was available. However, with the availability of a highly effective treatment, namely, tumour necrosis factor-α inhibitors (TNFi), the issue of early diagnosis of AS acquired an urgency. The Assessment of SpondyloArthritis International Society (ASAS) classification criteria published in 2009 was a significant step towards this goal. These criteria described an early stage of the disease where sacroiliitis was demonstrable only on MRI but not on standard radiograph. Therefore, this stage of the disease was labelled “nonradiographic axial SpA” (nr-axSpA). But questions have been raised if, in search of early diagnosis, specificity was compromised. The Federal Drug Administration (FDA, USA) withheld approval for the use of TNFi in patients with nr-axSpA because of issues related to the specificity of these criteria. This review attempts to clarify some of these aspects of the nr-axSpA-AS relationship and also tries to answer the question whether ASAS classifiable radiographic axial spondyloarthritis (r-axSpA) term can be interchangeably used with the term AS. PMID:28555158

  16. Multiphasic helical CT of hepatocellular carcinoma. Evaluation after chemoembolization; Tomografia Computerizzata spirale multifasica dell'epatocarcinoma. Valutazione dopo chemioembolizzazione

    Energy Technology Data Exchange (ETDEWEB)

    Catalano, O.; Esposito, M.; Sandomenico, F.; Siani, A. [Ospedale S. Maria delle Grazie, Pozzuoli, NA (Italy). Servizio di Radiologia; Nunziata, A. [Ospedale S. Maria delle Grazie, Naples (Italy). Area di Diagnostica per Immagini

    2000-06-01

    technique has several limitations, as also shown in recent literature papers and its clinical applications should be reduced. Multiphase helical studies may provide useful information and should be performed routinely in patients treated with chemo embolization. The present availability of alternative tools such as contrast-enhanced Doppler US and MRI should also be stressed and their potential role investigated. [Italian] Il presente lavoro si propone di illustrare la personale esperienza sull'integrazione della Tomografia Computerizzata (TC) senza mdc ev (Lipiodol-TC) con la TC spirale con mdc ev multifasica nella valutazione dei pazienti con epatocarcinoma trattati con chemioembolizzazione e analizzare il possibile ruolo attuale della TC con mdc oleoso. Si sono valutati retrospettivamente gli esami di 42 pazienti consecutivi sottoposti a chemioembolizzazione globale nell'arco di 2 anni. Lo studio con TC e' stato praticato 1830 giorni dopo il trattamento. La Lipiodol-TC e' stata eseguita con acquisione volumetrica; si sono considerati noduli quelle aree delimitate con ritenzione densa del mdc oleoso e si sono distinti la captazione in: 0=assente, I=inferiore a 10% dell'area del tumore, II=minore di 50%, III=maggiore di 50%, IV=omogenea. Lo studio con TC spirale con mdc ev e' stato praticato con tecnica bifasica in 28 pazienti e trifasica in 14; abbiamo ritenuto come nodulari quelle aree ben delimitate e relativamente omogenee con iperdensita' nella fase arteriosa e ipo-isodensita' in quella portale e/o tardiva oppure con ipo-isodensita' nella fase arteriosa e in quella portale e/o tardiva. Con la Lipiodol-TC sono stati identificati 65 noduli (1-5/paziente, media 1,5), 15 con grado I, 21 con grado II, 20 con grado III e 9 con grado IV. Con la TC multifasica sono stati dimostrati 6 noduli supplementari in 5 pazienti, di cui 5 iper-e uno ipovascolare, ed e' stata documentata meglio la reale morfovolumetria dei noduli con

  17. Tumores malignos da cavidade nasal: tomografia computadorizada e ressonância magnética Malignant tumors of the nasal cavity: computed tomography and magnetic resonance imaging

    Directory of Open Access Journals (Sweden)

    Ricardo Pires de Souza

    2004-10-01

    Full Text Available OBJETIVO: Este estudo propõe-se a avaliar o papel da tomografia computadorizada e da ressonância magnética na caracterização da extensão profunda dos tumores malignos da cavidade nasal. MATERIAIS E MÉTODOS: Entre 1990 e 2000 foram avaliados, retrospectivamente, 12 pacientes com diagnóstico de tumores malignos da cavidade nasal atendidos nos Departamentos de Diagnóstico por Imagem e Cirurgia de Cabeça e Pescoço do Complexo Hospitalar Heliópolis, São Paulo, SP. Todos os casos foram confirmados com exame anatomopatológico. RESULTADOS: Foi identificada extensão para os seios maxilares e etmoidal em seis pacientes, para a cavidade nasal contralateral, órbita e lâmina crivosa em cinco pacientes, para a nasofaringe e espaço mastigatório em dois pacientes, e para o seio cavernoso, fossas cranianas anterior e média, fossa pterigomaxilar, fissuras orbitárias superior e inferior, seio frontal, seio etmoidal contralateral, lâmina crivosa contralateral, palato duro e fossa pterigopalatina em um paciente. CONCLUSÃO: A análise precisa da extensão local e disseminação tumoral dada pela tomografia computadorizada e ressonância magnética desempenha papel importante no planejamento terapêutico, influenciando também o prognóstico.OBJECTIVE: The aim of this study is to evaluate the role of computed tomography and magnetic resonance imaging in the characterization of deep tissue extension of malignant tumors of the nasal cavity. MATERIALS AND METHODS: Twelve patients diagnosed with malignant tumors of the nasal cavity were retrospectively evaluated at the Departments of Diagnostic Imaging and Head and Neck Surgery of the "Complexo Hospitalar Heliópolis", São Paulo, Brazil, between 1990 and 2000. All cases were confirmed by histopathologic examination. RESULTS: Extension to the maxillary and ethmoid sinuses was identified in six patients, extension to contralateral nasal cavity, orbit and lamina cribosa in five patients, extension to

  18. O valor da tomografia computadorizada na mudança do paradigma cirúrgico do carcinoma epidermóide de boca e orofaringe

    Directory of Open Access Journals (Sweden)

    Joel Pinheiro de Brito Junior

    Full Text Available OBJETIVO: Determinar a importância da tomografia computadorizada na mudança do paradigma cirúrgico no carcinoma espinocelular (CEC da boca e orofaringe. MÉTODO: De 1991 e 2004, nos Departamentos de Cirurgia de Cabeça e Pescoço/ORL e Radiologia do Hospital Heliópolis, foram analisados, retrospectivamente, tomografias computadorizadas de 30 pacientes, 25 homens e cinco mulheres, com idades variando de 25 a 77 anos, todos com diagnóstico de carcinoma epidermóide do soalho da boca e/ou da língua oral e orofaringe. Todos os exames foram avaliados por dois radiologistas, separadamente, sem o conhecimento prévio do estadiamento clínico, sendo analisada a disseminação local-regional para os diferentes sítios. Para análise interobservadores, o índice Kappa foi calculado para estimar a concordância entre os mesmos, sendo o nível de significância adotado o valor de 0,05. RESULTADO: A análise da concordância entre os observadores foi considerada excelente (Kappa: 0,81 - 1,00 para três subsítios (linha média, espaço mastigador e cadeia linfonodal jugulo-carotídea alta; boa (Kappa: 0,61 - 0,80 para 10 subsítios (soalho da boca e língua oral, ramo da mandíbula, trígono retromolar, espaço submandibular, loja amigdalina e cadeias linfonodais submentoniana, submandibular, jugulo-carotídea média, jugulo-carotídea baixa e espinal; moderada (Kappa: 0,41 - 0,60 para dois subsítios (corpo da mandíbula e base da língua e não foi possível calcular o Kappa para um subsítio (cadeia linfonodal retrofaríngea. CONCLUSÃO: A concordância interobservadores predominou de boa a excelente, sendo os valores estatisticamente significantes.

  19. Edema pulmonar hidrostático: aspectos na tomografia computadorizada de alta resolução Hydrostatic pulmonary edema: high-resolution computed tomography aspects

    Directory of Open Access Journals (Sweden)

    Cláudia Maria Cunha Ribeiro

    2006-12-01

    Full Text Available OBJETIVO: A proposta deste estudo foi caracterizar por meio de tomografia computadorizada de alta resolução do tórax as principais alterações pulmonares do edema pulmonar hidrostático. MÉTODOS: Foram analisadas, retrospectivamente, as tomografias de quinze pacientes com quadro clínico de edema pulmonar hidrostático, divididos em cinco principais grupos etiológicos: insuficiência cardíaca congestiva, valvulopatia mitral aguda, infarto agudo do miocárdio, miocardite e mediastinite fibrosante, tendo sido sete pacientes classificados no primeiro grupo e dois em cada um dos demais. RESULTADOS: Os principais achados do edema hidrostático foram opacidades em vidro fosco (100%, espessamento dos septos interlobulares (100%, derrame pleural (87% e espessamento do interstício peribroncovascular (80%. Outros achados menos comuns foram aumento do calibre dos vasos, consolidações e nódulos do espaço aéreo. CONCLUSÃO: O padrão predominante encontrado nos pacientes estudados foi o de opacidades em vidro fosco associadas a espessamento dos septos interlobulares (padrão de pavimentação em mosaico, com derrame pleural bilateral, predominante à direita.OBJECTIVE: This study aimed to use high-resolution computed tomography scans of the chest to characterize the principal alterations occurring in cases of hydrostatic pulmonary edema. METHODS: A retrospective analysis was made of the tomography scans of 15 patients presenting clinical profiles of hydrostatic pulmonary edema. The cases were divided into five groups by etiology: congestive heart failure (n = 7; acute mitral valve disease (n = 2; acute myocardial infarction (n = 2; myocarditis (n = 2; and fibrosing mediastinitis (n = 2. RESULTS: The principal findings in the cases of hydrostatic pulmonary edema were ground-glass opacities (in 100%, interlobular septal thickening (in 100%, pleural effusion (in 87% and peribronchovascular interstitial thickening (in 80%. Other, less common

  20. Avaliação da artéria etmoidal anterior pela tomografia computadorizada no plano coronal Anterior ethmoidal artery evaluation on coronal CT scans

    Directory of Open Access Journals (Sweden)

    Soraia Ale Souza

    2009-02-01

    Full Text Available O conhecimento da localização da artéria etmoidal anterior (AEA constitui etapa importante na cirurgia do recesso do seio frontal e do etmóide anterior. A tomografia computadorizada (TC, em especial no plano coronal pode fornecer reparos anatômicos que identificam o trajeto da AEA. OBJETIVO: Identificar os reparos anatômicos que caracterizam o trajeto da AEA na parede medial da órbita e na parede lateral da fossa olfatória. Verificar a correlação entre a presença de pneumatização supra-orbitária e a visualização do etmoidal anterior (canal da AEA. CASUÍSTICA E MÉTODOS: Estudo retrospectivo de 198 tomografias computadorizadas dos seios paranasais no plano coronal do período de agosto a dezembro de 2006. RESULTADOS: Pneumatização supra-orbitária foi identificada em 35% (70 exames. O canal da AEA foi caracterizado em 41% (81 exames. O sulco etmoidal anterior foi visualizado em 98% (194 dos exames e o forame etmoidal anterior foi identificado em todos os exames (100%. CONCLUSÃO: O forame etmoidal anterior e o sulco etmoidal anterior foram referências anatômicas presentes em quase 100% dos exames avaliados. Houve correlação entre a presença de pneumatização supra-orbitária e a caracterização do canal da AEA.The anterior ethmoidal artery (AEA is an important point for frontal and ethmoid sinuses surgery. CT scans can identify landmarks to help the surgeon find the AEA. AIM: To identify the landmarks of the AEA on the orbital medial wall and on the lateral wall of the olfactory fossa. and to correlate the presence of supraorbital ethmoidal cells with spotting the anterior ethmoidal artery canal. MATERIALS AND METHODS: Retrospective review of 198 direct coronal paranasal sinuses computed tomography (CT scans from August to December, 2006. RESULTS: Supraorbital pneumatization was seen in 35% (70 scans. The AEA canal was seen in 41% (81 scans. The anterior ethmoidal sulcus was seen in 98% (194 scans and the anterior

  1. Cladding axial elongation models for FRAP-T6

    International Nuclear Information System (INIS)

    Shah, V.N.; Carlson, E.R.; Berna, G.A.

    1983-01-01

    This paper presents a description of the cladding axial elongation models developed at the Idaho National Engineering Laboratory (INEL) for use by the FRAP-T6 computer code in analyzing the response of fuel rods during reactor transients in light water reactors (LWR). The FRAP-T6 code contains models (FRACAS-II subcode) that analyze the structural response of a fuel rod including pellet-cladding-mechanical-interaction (PCMI). Recently, four models were incorporated into FRACAS-II to calculate cladding axial deformation: (a) axial PCMI, (b) trapped fuel stack, (c) fuel relocation, and (d) effective fuel thermal expansion. Comparisons of cladding axial elongation measurements from two experiments with the corresponding FRAP-T6 calculations are presented

  2. The relation between anomalous magnetic moment and axial anomaly

    International Nuclear Information System (INIS)

    Teryaev, O.V.

    1990-12-01

    The conservation of total angular momentum of spinor particle leads to a simple relation between the famous Schwinger and Adler coefficients determining axial anomaly and anomalous magnetic moment, respectively. (author). 8 refs, 1 fig

  3. Defining active sacroiliitis on MRI for classification of axial spondyloarthritis

    DEFF Research Database (Denmark)

    Lambert, Robert G W; Bakker, Pauline A C; van der Heijde, Désirée

    2016-01-01

    OBJECTIVES: To review and update the existing definition of a positive MRI for classification of axial spondyloarthritis (SpA). METHODS: The Assessment in SpondyloArthritis International Society (ASAS) MRI working group conducted a consensus exercise to review the definition of a positive MRI...... for inclusion in the ASAS classification criteria of axial SpA. Existing definitions and new data relevant to the MRI diagnosis and classification of sacroiliitis and spondylitis in axial SpA, published since the ASAS definition first appeared in print in 2009, were reviewed and discussed. The precise wording....... CONCLUSION: The definition of a positive MRI for classification of axial SpA should continue to primarily depend on the imaging features of 'active sacroiliitis' until more data are available regarding MRI features of structural damage in the sacroiliac joint and MRI features in the spine and their utility...

  4. The geometrical theory of diffraction for axially symmetric reflectors

    DEFF Research Database (Denmark)

    Rusch, W.; Sørensen, O.

    1975-01-01

    The geometrical theory of diffraction (GTD) (cf. [1], for example) may be applied advantageously to many axially symmetric reflector antenna geometries. The material in this communication presents analytical, computational, and experimental results for commonly encountered reflector geometries...

  5. Time Domain Terahertz Axial Computed Tomography Non Destructive Evaluation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to demonstrate key elements of feasibility for a high speed automated time domain terahertz computed axial tomography (TD-THz CT) non destructive...

  6. Pole prescription in axial gauge at finite temperature

    Science.gov (United States)

    Kreuzer, Maximilian; Nachbagauer, Herbert

    1991-11-01

    We establish Yang-Mills theory at finite temperature in axial gauge. We encounter the breakdown of the Hata-Kugo expression for the partition function in the special choice of temporal axial gauge. For n ≠ 0 the finite temperature propagator is calculated in both the imaginary time formalism and the real time formalism. In the latter we recover the Leibbrandt-Mandelstam prescription in the lijit T→0. As a check we calculate the mean energy to lowest order.

  7. Pole prescription in axial gauge at finite temperature

    Energy Technology Data Exchange (ETDEWEB)

    Kreuzer, M.; Nachbagauer, H. (Technische Univ., Vienna (Austria). Inst. fuer Theoretische Physik)

    1991-11-14

    We establish Yang-Mills theory at finite temperature in axial gauge. We encounter the breakdown of the Hata-Kugo expression for the partition function in the special choice of temporal axial gauge. For n {ne} 0 the finite temperature propagator is calculated in both the imaginary time formalism and the real time formalism. In the latter we recover the Leibbrandt-Mandelstam prescription in the limit T {yields} 0. As a check we calculate the mean energy to lowest order. (orig.).

  8. Axial myopia in computed and magnetic resonance tomography

    Energy Technology Data Exchange (ETDEWEB)

    Beyer-Enke, S.A.; Goerich, J.; Gamroth, A.

    1987-08-01

    The case of a 44-year old woman suffering from amblyopia on the left eye with unilateral proptosis caused by axial (progressive) myopia is presented. The clinical and radiological findings were discussed in reference to the literature. The diagnosis was established by ruling out neoplastic, inflammatory or endocrine causes for the exophtalmos. CT and MR scans revealed an enlarged left globe without evidence of orbital masses. The findings were regarded as typical for the diagnosis at axial myopia.

  9. Flutter of a fan blade in supersonic axial flow

    Science.gov (United States)

    Kielb, Robert E.; Ramsey, John K.

    1988-01-01

    An application of a simple aeroelastic model to an advanced supersonic axial flow fan is presented. Lane's cascade theory is used to determine the unsteady aerodynamic loads. Parametric studies are performed to determine the effects of mode coupling, Mach number, damping, pitching axis location, solidity, stagger angle, and mistuning. The results show that supersonic axial flow fan and compressor blades are susceptible to a strong torsional mode flutter having critical reduced velocities which can be less than one.

  10. Axial loading cross screw fixation for the Austin bunionectomy.

    Science.gov (United States)

    Rigby, Ryan B; Fallat, Lawrence M; Kish, John P

    2011-01-01

    The Austin procedure has become a common method of osteotomy for the correction of hallux abductovalgus when indicated. The V-type configuration is intrinsically stable but not without complications. One complication encountered is rotation and/or displacement of the capital fragment. We present the use of an axial loading screw in conjunction with a dorsally placed compression screw. The benefit to this technique lies in the orientation of the axial loading screw, because it is directed to resist the ground reactive forces while also providing a second point of fixation in a crossing screw design. In a head-to-head biomechanical comparison, we tested single dorsal screw fixation versus double screw fixation, including both the dorsal and the axial loading screws in 10 metatarsal Sawbones(®) (Pacific Research Laboratories Inc, Vashon, WA). Five metatarsals received single dorsal screw fixation and five received the dorsal screw and the additional axial loading screw. The metatarsals were analyzed on an Instron compression device for comparison; 100% of the single screw fixation osteotomies failed with compression at an average peak load of 205 N. Four of five axial loading double screw fixation osteotomies did not fail. This finding suggests that the addition of an axial loading screw providing cross screw orientation significantly increases the stability of the Austin osteotomy, ultimately decreasing the likelihood of displacement encountered in the surgical repair of hallux abductovalgus. Copyright © 2011 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  11. Reactive control of subsonic axial fan noise in a duct.

    Science.gov (United States)

    Liu, Y; Choy, Y S; Huang, L; Cheng, L

    2014-10-01

    Suppressing the ducted fan noise at low frequencies without varying the flow capacity is still a technical challenge. This study examines a conceived device consisting of two tensioned membranes backed with cavities housing the axial fan for suppression of the sound radiation from the axial fan directly. The noise suppression is achieved by destructive interference between the sound fields from the axial fan of a dipole nature and sound radiation from the membrane via vibroacoustics coupling. A two-dimensional model with the flow effect is presented which allows the performance of the device to be explored analytically. The air flow influences the symmetrical behavior and excites the odd in vacuo mode response of the membrane due to kinematic coupling. Such an asymmetrical effect can be compromised with off-center alignment of the axial fan. Tension plays an important role to sustain the performance to revoke the deformation of the membrane during the axial fan operation. With the design of four appropriately tensioned membranes covered by a cylindrical cavity, the first and second blade passage frequencies of the axial fan can be reduced by at least 20 dB. The satisfactory agreement between experiment and theory demonstrates that its feasibility is practical.

  12. Axial design of nuclear fuel using path relinking; Diseno axial de combustible nuclear utilizando path relinking

    Energy Technology Data Exchange (ETDEWEB)

    Castillo, A.; Torres, M.; Ortiz, J. J.; Perusquia, R.; Hernandez, J. L.; Montes, J. L. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)]. e-mail: jacm@nuclear.inin.mx

    2008-07-01

    In the present work the preliminary results were obtained with the zoctli system whose purpose is the axial design of assembly of nuclear fuel under certain considerations. For the mentioned design well-know cells were already used and that they have been proven in diverse cycles of operation in the nuclear power plant of Laguna Verde. The design contemplates fuels assemblies of 10x10 and with 2 water channels. The assembly was distributed in 6 axial zones according to its structure. In order to take to end the optimization is was used the well-known technique like Path relinking and to find the group of previous solutions required by this technique uses the technical Taboo search. In order to work with Path relinking, 5 trajectories was taken in to account from a set of 5 previous solutions generated with theTaboo search, the update of the group of solutions is carried out in dynamic form. In the case of the Taboo search it was used a list of variable size, it was implement an aspiration approach, it was used the vector of frequencies and due to the cost of the evaluation of the objective function, only it was review 5% of the vicinity. For the objective function was considered the limit thermal, the axial profile of power, the effective multiplication factor and the margin of having turned off in cold. In order to prove the design system, it was used a balance cycle with a value of reference of 0.9928 for the effective multiplication factor that is equivalent to a produced energy of 10896 MWd/TU at the end of operation to full power. The designed assemblies were placed both in one of lots different from fresh assemblies on which it counts the referred cycle. At the end one a comparison with the results obtained with other techniques and under similar conditions is made. The results obtained until the moment show an appropriate performance of the system. It is possible to indicate that a small inconvenient is the amount of consumed resources of calculation during

  13. High Precision Axial Coordinate Readout for an Axial 3-D PET Detector Module using a Wave Length Shifter Strip Matrix

    CERN Document Server

    Braem, André; Joram, C; Séguinot, Jacques; Weilhammer, P; De Leo, R; Nappi, E; Lustermann, W; Schinzel, D; Johnson, I; Renker, D; Albrecht, S

    2007-01-01

    We describe a novel method to extract the axial coordinate from a matrix of long axially oriented crystals, which is based on wavelength shifting plastic strips. The method allows building compact 3-D axial gamma detector modules for PET scanners with excellent 3-dimensional spatial, timing and energy resolution while keeping the number of readout channels reasonably low. A voxel resolution of about 10 mm3 is expected. We assess the performance of the method in two independent ways, using classical PMTs and G-APDs to read out the LYSO (LSO) scintillation crystals and the wavelength shifting strips. We observe yields in excess of 35 photoelectrons from the strips for a 511 keV gamma and reconstruct the axial coordinate with a precision of about 2.5 mm (FWHM).

  14. Tomografia computadorizada do tórax de cadelas portadoras de neoplasias malignas: II - Avaliação dos campos pulmonares

    Directory of Open Access Journals (Sweden)

    Ana Carolina Brandão de Campos Fonseca Pinto

    2007-06-01

    Full Text Available Visto a importância das neoplasias mamárias na clínica médico-veterinária e as novas perspectivas do diagnóstico por imagem, o presente trabalho visou comparar o exame tomográfico contrastado com o exame radiográfico simples dos campos pulmonares de cadelas portadoras de tumores mamários malignos. Para tanto, foram realizados exames de tomografia computadorizada contrastada da cavidade torácica de vinte fêmeas da espécie canina, de diferentes raças e idades, portadoras de neoplasias mamárias malignas encaminhadas ao Serviço de Diagnóstico por Imagem do Hospital Veterinário da Faculdade de Medicina Veterinária e Zootecnia da Universidade de São Paulo pelos Serviços de Obstetrícia e Ginecologia e de Cirurgia de Pequenos Animais da mesma instituição. Concluiu-se que, o exame tomográfico se mostrou um importante complemento do exame radiográfico na pesquisa de metástases de neoplasias mamárias em cadelas no que se refere à avaliação do interstício pulmonar.

  15. Studio del danneggiamento mediante tomografia in luce del sincrotrone: impatto di un cono d’ombra sulla qualità finale delle ricostruzioni

    Directory of Open Access Journals (Sweden)

    Andrea Bernasconi

    2010-07-01

    Full Text Available Un’accurata osservazione della geometria tridimensionale di cricche e difetti è necessaria per lo studio dei meccanismi alla base del processo di danneggiamento. I metodi convenzionali utilizzati a questo scopo sono distruttivi o non possiedono una sufficiente risoluzione. Le tecniche di imaging che utilizzano la luce di sincrotrone, ed in particolare la microtomografia (micro-CT a raggi X, invece, uniscono i vantaggi di una tecnica non distruttiva ad un’elevata risoluzione spaziale e risultano quindi particolarmente interessanti. Un limite all’applicazione di questa tecnica è costituito dalla propensione della cricca a richiudersi una volta rimosso il carico che ha provocato il danneggiamento, superabile attraverso l’impiego di un dispositivo in grado di esercitare un carico di trazione durante l’acquisizione dei dati. Facendo riferimento al set-up sperimentale della linea SYRMEP di Elettra, il sincrotrone di Trieste, e tralasciando per il momento i vincoli legati a pesi e ingombri, è possibile pensare di inserire tra camera di ionizzazione e CCD una macchina per prove di trazione mono-colonna commerciale, in grado di mantenere aperto il difetto per tutta la durata della tomografia. In questo lavoro viene valutato l’impatto di questo vincolo sulla qualità finale delle ricostruzioni.

  16. Computed tomography image of the mediastinal and axillary lymph nodes in clinically sound Rottweilers Imagem por tomografia computadorizada dos linfonodos axilares e mediastinais de cães rottweilers clinicamente saudáveis

    Directory of Open Access Journals (Sweden)

    Ana Carolina B. Fonseca Pinto

    2013-03-01

    smallest diameter of the axillary and mediastinal lymph nodes not surpassed 7mm and 8mm respectively. Their attenuations were equal or smaller than that of musculature in the post contrast scan.A tomografia computadorizada é uma modalidade diagnóstica que possibilita a avaliação detalhada dos linfonodos e que é capaz de detectar mais precocemente alterações envolvendo estas estruturas, que modalidades de imagem como a radiografia e a ultrassonografia. Tendo em vista a escassez de informações na literatura veterinária esta pesquisa objetivou fornecer informações sobre os aspectos tomográficos normais dos linfonodos axilares e mediastinais em cães. Realizou-se o exame tomográfico de 15 cães adultos, machos e fêmeas, da raça Rottweiler, selecionados como clinicamente normais por meio de anamnese, exame físico, hemograma, perfil bioquímico renal e hepático, eletrocardiograma e exame radiográfico do tórax. Após a injeção intravenosa do contraste iodado hidrossolúvel iônico, realizaram-se cortes tomográficos transversais do tórax com 10mm de espessura e 10mm de incremento em um tomógrafo axial. Os exames tomográficos foram avaliados buscando-se identificar os linfonodos axilares e mediastinais. Quando visibilizados, os linfonodos foram mensurados em seu menor eixo e sua atenuação foi comparada com a da musculatura. Foram calculados a média e desvio padrão da idade, do peso, do comprimento dos animais e do menor eixo dos linfonodos axilares e mediastinais. A média de idade dos animais e o desvio padrão foram de 3,87 anos ±2,03, do peso foi de 41,13kg ± 5,12 e do comprimento dos animais foi de 89,61cm ±2,63. Os linfonodos axilares foram visibilizados em 60% dos animais, a média das mensurações dos menores diâmetros e o desvio padrão foi de 3,58mm ±2,02 com valor mínimo de 1mm e máximo de 7mm. Dos 13 linfonodos observados 61,53% apresentaram-se hipoatenuantes comparativamente a musculatura e 30,77% isoatenuantes. Os linfonodos

  17. Axial Lengths in Children with Recessive Cornea Plana.

    Science.gov (United States)

    Al Hazimi, Amro; Khan, Arif O

    2015-06-01

    While flat keratometry contributes to the hyperopia and associated refractive accommodative esotropia that is part of recessive cornea plana, whether or not axial lengths are abnormally short in the disease is unclear. In this study we assess this possibility. Prospective (2010-2012) axial length measurement (IOLmaster; Carl Zeiss, Oberkochen, Germany) of affected right eyes and comparison to right eyes with refractive accommodative esotropia only. Keratometry and refraction were also performed. For eight affected right eyes (age 10-12 years; seven families) axial length ranged from 21.46-24.80 mm (mean 23.34). Best corrected visual acuity ranged from 20/25 to 20/50, keratometry from 25.33-39.80 diopters (D) [mean 31.80], and refraction from +2.00 to +14.00 D (mean +7.22). For 50 control right eyes (age 4-12 years), axial length ranged from 19.87-23.66 mm (mean 21.6). Best-corrected visual acuity was 20/25 or better, keratometry ranged from 39.81-46.25 D (mean 42.42), and refraction from +2.25 to +8.00 D (mean 4.71). Axial lengths were longer in the affected group (2-tailed unpaired t-test p value 0.000005) despite greater hyperopia (2-tailed unpaired t-test p value 0.001). Despite greater hyperopia, axial lengths were longer in eyes with recessive cornea plana, evidence that axial lengths are not shortened by the disease. Keratometry in children with cornea plana was below the range of controls and was the major factor underlying the phenotype's hyperopia.

  18. Continuous millennial decrease of the Earth's magnetic axial dipole

    Science.gov (United States)

    Poletti, Wilbor; Biggin, Andrew J.; Trindade, Ricardo I. F.; Hartmann, Gelvam A.; Terra-Nova, Filipe

    2018-01-01

    Since the establishment of direct estimations of the Earth's magnetic field intensity in the first half of the nineteenth century, a continuous decay of the axial dipole component has been observed and variously speculated to be linked to an imminent reversal of the geomagnetic field. Furthermore, indirect estimations from anthropologically made materials and volcanic derivatives suggest that this decrease began significantly earlier than direct measurements have been available. Here, we carefully reassess the available archaeointensity dataset for the last two millennia, and show a good correspondence between direct (observatory/satellite) and indirect (archaeomagnetic) estimates of the axial dipole moment creating, in effect, a proxy to expand our analysis back in time. Our results suggest a continuous linear decay as the most parsimonious long-term description of the axial dipole variation for the last millennium. We thus suggest that a break in the symmetry of axial dipole moment advective sources occurred approximately 1100 years earlier than previously described. In addition, based on the observed dipole secular variation timescale, we speculate that the weakening of the axial dipole may end soon.

  19. Amphiregulin Antibody and Reduction of Axial Elongation in Experimental Myopia

    Directory of Open Access Journals (Sweden)

    Wen Jun Jiang

    2017-03-01

    Full Text Available To examine the mechanism of ocular axial elongation in myopia, guinea pigs (age: 2–3 weeks which either underwent unilateral or bilateral lens-induced myopization (group 1 or which were primarily myopic at baseline (group 2 received unilateral intraocular injections of amphiregulin antibody (doses: 5, 10, or 15 μg three times in intervals of 9 days. A third group of emmetropic guinea pigs got intraocular unilateral injections of amphiregulin (doses: 0.25, 0.50 or 1.00 ng, respectively. In each group, the contralateral eyes received intraocular injections of Ringer's solution. In intra-animal inter-eye comparison and intra-eye follow-up comparison in groups 1 and 2, the study eyes as compared to the contralateral eyes showed a dose-dependent reduction in axial elongation. In group 3, study eyes and control eyes did not differ significantly in axial elongation. Immunohistochemistry revealed amphiregulin labelling at the retinal pigment epithelium in eyes with lens-induced myopization and Ringer's solution injection, but not in eyes with amphiregulin antibody injection. Intraocular injections of amphiregulin-antibody led to a reduction of lens-induced axial myopic elongation and of the physiological eye enlargement in young guinea pigs. In contrast, intraocularly injected amphiregulin in a dose of ≤1 ng did not show a significant effect. Amphiregulin may be one of several essential molecular factors for axial elongation.

  20. Analysis of axial compressive loaded beam under random support excitations

    Science.gov (United States)

    Xiao, Wensheng; Wang, Fengde; Liu, Jian

    2017-12-01

    An analytical procedure to investigate the response spectrum of a uniform Bernoulli-Euler beam with axial compressive load subjected to random support excitations is implemented based on the Mindlin-Goodman method and the mode superposition method in the frequency domain. The random response spectrum of the simply supported beam subjected to white noise excitation and to Pierson-Moskowitz spectrum excitation is investigated, and the characteristics of the response spectrum are further explored. Moreover, the effect of axial compressive load is studied and a method to determine the axial load is proposed. The research results show that the response spectrum mainly consists of the beam's additional displacement response spectrum when the excitation is white noise; however, the quasi-static displacement response spectrum is the main component when the excitation is the Pierson-Moskowitz spectrum. Under white noise excitation, the amplitude of the power spectral density function decreased as the axial compressive load increased, while the frequency band of the vibration response spectrum increased with the increase of axial compressive load.

  1. Development and Testing of an Axial Halbach Magnetic Bearing

    Science.gov (United States)

    Eichenberg, Dennis J.; Gallo, Christopher A.; Thompson, William K.

    2006-01-01

    The NASA Glenn Research Center has developed and tested a revolutionary Axial Halbach Magnetic Bearing. The objective of this work is to develop a viable non-contact magnetic thrust bearing utilizing Halbach arrays for all-electric flight, and many other applications. This concept will help to reduce harmful emissions, reduce the Nation s dependence on fossil fuels and mitigate many of the concerns and limitations encountered in conventional axial bearings such as bearing wear, leaks, seals and friction loss. The Axial Halbach Magnetic Bearing is inherently stable and requires no active feedback control system or superconductivity as required in many magnetic bearing designs. The Axial Halbach Magnetic Bearing is useful for very high speed applications including turbines, instrumentation, medical systems, computer memory systems, and space power systems such as flywheels. Magnetic fields suspend and support a rotor assembly within a stator. Advanced technologies developed for particle accelerators, and currently under development for maglev trains and rocket launchers, served as the basis for this application. Experimental hardware was successfully designed and developed to validate the basic principles and analyses. The report concludes that the implementation of Axial Halbach Magnetic Bearings can provide significant improvements in rotational system performance and reliability.

  2. Modeling Effects of Axial Extension on Arterial Growth and Remodeling

    Science.gov (United States)

    Valentín, A.; Humphrey, J.D.

    2013-01-01

    Diverse mechanical perturbations elicit arterial growth and remodeling responses that appear to optimize structure and function so as to achieve mechanical homeostasis. For example, it is well known that functional adaptations to sustained changes in transmural pressure and blood flow primarily affect wall thickness and caliber to restore circumferential and wall shear stresses toward normal. More recently, however, it has been shown that changes in axial extension similarly prompt dramatic cell and matrix reorganization and turnover, resulting in marked changes in unloaded geometry and mechanical behavior that presumably restore axial stress toward normal. Because of the inability to infer axial stress from in vivo measurements, simulations are needed to examine this hypothesis and to guide the design of future experiments. In this paper, we show that a constrained mixture model predicts salient features of observed responses to step increases in axial extension, including marked increases in fibrous constituent production, leading to a compensatory lengthening that restores original mechanical behavior. Because axial extension can be modified via diverse surgical procedures, including bypass operations and exploited in tissue regeneration research, there is a need for increased attention to this important aspect of arterial biomechanics and mechanobiology. PMID:19649667

  3. Avaliação da capacidade de identificação de prematuridades oclusais, por meio cortes paraxiais obtidos de tomografias computadorizadas de feixe cônico (Cone Beam)

    OpenAIRE

    Machado, Naila Aparecida de Godoi

    2010-01-01

    O objetivo deste estudo foi avaliar a capacidade de identificação de prematuridades oclusais, por meio de cortes paraxiais de tomografias computadorizadas de feixe cônico, confrontando o parecer destas imagens, estabelecido por profissionais de diferentes áreas odontológicas, com a análise clínica obtida por meio de marcações com papel carbono. Dezesseis pacientes jovens assintomáticos foram submetidos a um exame clínico inicial e em seguida foram confeccionados dispositivos...

  4. Detecção de fraturas radiculares em imagens de tomografia computadorizada de feixe cônico utilizando diferentes parâmetros de exposição e materiais intracanais

    OpenAIRE

    Pinto, Martina Gerlane de Oliveira

    2015-01-01

    O objetivo deste estudo foi avaliar a detecção de fraturas radiculares (FRs) em imagens de Tomografia Computadorizada de Feixe Cônico (TCFC) utilizando diferentes parâmetros de exposição e analisar a influência da guta- percha, do núcleo metálico fundido e do pino de fibra de vidro no diagnóstico das FRs, assim como a formação de artefatos em TCFC. Cento e sessenta dentes foram selecionados e divididos em quatro grupos de acordo com o material de preenchimento (sem guta-percha, com guta-perch...

  5. Comparação do comprimento de trabalho do canal radicular usando tomografia computadorizada de feixe cônico, radiografia periapical e localizador apical eletrônico

    OpenAIRE

    MORAIS, André Luiz Gomide de

    2012-01-01

    Introdução: Estratégias para obtenção do comprimento de trabalho para preparar e obturar canais radiculares têm sido tema relevante de discussão em Endodontia. O objetivo deste estudo foi comparar in vivo as medidas de comprimento de trabalho do canal radicular determinadas por meio da tomografia computadorizada de feixe cônico (TCFC) com as obtidas por meio de radiografia periapical e localizador apical eletrônico. Metodologia: Foram avaliados os comprimentos de trabalho dos canais radicular...

  6. Thermocapillary Convection in Floating Zone with Axial Magnetic Fields

    Science.gov (United States)

    Liang, Ruquan; Yang, Shuo; Li, Jizhao

    2014-02-01

    Numerical simulations on the effects of axial magnetic fields on the thermocapillary convection in a liquid bridge of silicone-oil-based ferrofluid under zero gravity have been conducted. The Navier-Stokes equations coupled with the energy conservation equation are solved on a staggered grid, and the mass conserving level set approach is used to capture the free surface deformation of the liquid bridge. The obvious effects of the magnetic fields on the flow pattern as well as the velocity and temperature distributions in the liquid bridge can be detected. The axial magnetic fields suppress the thermocapillary convection and a stagnant flow zone is formed between the circulating flow and the symmetric axis as the magnetic fields increase. The axial magnetic fields affect not only the velocity level inside the liquid bridge but also the velocity level on the free surface. The temperature contours near the free surface illustrates conduction-type temperature profiles at moderate strength fields.

  7. Ball Screw Actuator Including an Axial Soft Stop

    Science.gov (United States)

    Wingett, Paul T. (Inventor); Forrest, Steven Talbert (Inventor); Abel, Steve (Inventor); Woessner, George (Inventor); Hanlon, Casey (Inventor)

    2016-01-01

    An actuator includes an actuator housing, a ball screw, and an axial soft stop assembly. The ball screw extends through the actuator housing and has a first end and a second end. The ball screw is coupled to receive a drive force and is configured, upon receipt of the drive force, to selectively move in a retract direction and an extend direction. The axial soft stop assembly is disposed within the actuator housing. The axial soft stop assembly is configured to be selectively engaged by the ball screw and, upon being engaged thereby, to translate, with compliance, a predetermined distance in the extend direction, and to prevent further movement of the ball screw upon translating the predetermined distance.

  8. Improvement of axial power distribution synthesis methodology in CPC

    International Nuclear Information System (INIS)

    Kim, H. H.; Gee, S. G.;; Kim, Y. B.; In, W. K.

    2003-01-01

    The capability of axial power distribution synthesis in CPC plays an important role in determining the DNBR and LPD trip caused by CPC. The axial power distribution is synthesized using the cubic spline function based on the three excore detector signals. The axial power distributions are categorized into 8 function sets and each sets are stored as pre-calculated values in CPC to save the calculation time. In this study, the additional function sets, the real break-point function sets and the polynomial function are suggested to evaluate the possibility of improving the synthesis capability in CPC. In addition, RMS errors are compared and evaluated for each synthesis method. As a result, it was confirmed that the function sets stored in CPC were not optimal. The analysis result showed that RMS error could be reduced by selecting the proper function sets suggested in this study

  9. Axially modulated arch resonator for logic and memory applications

    KAUST Repository

    Hafiz, Md Abdullah Al

    2018-01-17

    We demonstrate reconfigurable logic and random access memory devices based on an axially modulated clamped-guided arch resonator. The device is electrostatically actuated and the motional signal is capacitively sensed, while the resonance frequency is modulated through an axial electrostatic force from the guided side of the microbeam. A multi-physics finite element model is used to verify the effectiveness of the axial modulation. We present two case studies: first, a reconfigurable two-input logic gate based on the linear resonance frequency modulation, and second, a memory element based on the hysteretic frequency response of the resonator working in the nonlinear regime. The energy consumptions of the device for both logic and memory operations are in the range of picojoules, promising for energy efficient alternative computing paradigm.

  10. Program for beam optical computation of axial symmetrical electrostatic systems

    International Nuclear Information System (INIS)

    Ke Jianlin; Wu Chunlei; Zhou Changgeng

    2012-01-01

    The beam optical computation of axial symmetrical electrostatic systems is very important in the design and test of low-energy accelerators such as Cock-Croft and Van de Graaf accelerators. In this paper, a program for the beam optical computation of these structures has been developed using transfer matrix method. The electrostatic field region is divided into several small intervals in the program, and then the beam envelope is calculated interval-to-interval from the axial potential distribution, which is calculated by other electromagnetic field simulation software such as Maxwell SV. Space charge effect is included so that the program can be used in the computation of intense beam, while nonlinear effect is beyond its ability. The program can be used in the calculation of beam optics in most complicated axial symmetrical electrostatic fields, and the computing time required is very short. (authors)

  11. Progressive atlanto-axial subluxation in Behcet's disease

    International Nuclear Information System (INIS)

    Kim, Sang-hyuk; Eoh, Whan

    2010-01-01

    Behcet's disease is a chronic inflammatory condition involving several organs, such as the skin, mucous membranes, eyes, joints, intestines, lungs and central nervous system. It rarely affects the spinal column. We describe a case of progressive atlanto-axial subluxation in a 44-year-old woman with Behcet's disease. The patient started complaining of posterior neck pain 10 years after the diagnosis of her Behcet's disease. Initial radiographs showed no abnormal finding, but follow-up radiographs 6 month later demonstrated atlanto-axial subluxation. To the best of our knowledge, this is the second reported case in the worldwide literature of an atlanto-axial instability in a patient with Behcet's disease. (orig.)

  12. Bifurcation and chaos of an axially accelerating viscoelastic beam

    International Nuclear Information System (INIS)

    Yang Xiaodong; Chen Liqun

    2005-01-01

    This paper investigates bifurcation and chaos of an axially accelerating viscoelastic beam. The Kelvin-Voigt model is adopted to constitute the material of the beam. Lagrangian strain is used to account for the beam's geometric nonlinearity. The nonlinear partial-differential equation governing transverse motion of the beam is derived from the Newton second law. The Galerkin method is applied to truncate the governing equation into a set of ordinary differential equations. By use of the Poincare map, the dynamical behavior is identified based on the numerical solutions of the ordinary differential equations. The bifurcation diagrams are presented in the case that the mean axial speed, the amplitude of speed fluctuation and the dynamic viscoelasticity is respectively varied while other parameters are fixed. The Lyapunov exponent is calculated to identify chaos. From numerical simulations, it is indicated that the periodic, quasi-periodic and chaotic motions occur in the transverse vibrations of the axially accelerating viscoelastic beam

  13. Reducing gait speed affects axial coordination of walking turns.

    Science.gov (United States)

    Forsell, Caroline; Conradsson, David; Paquette, Caroline; Franzén, Erika

    2017-05-01

    Turning is a common feature of daily life and dynamic coordination of the axial body segments is a cornerstone for safe and efficient turning. Although slow walking speed is a common trait of old age and neurological disorders, little is known about the effect of walking speed on axial coordination during walking turns. The aim of this study was to investigate the influence of walking speed on axial coordination during walking turns in healthy elderly adults. Seventeen healthy elderly adults randomly performed 180° left and right turns while walking in their self-selected comfortable pace and in a slow pace speed. Turning velocity, spatiotemporal gait parameters (step length and step time), angular rotations and angular velocity of the head and pelvis, head-pelvis separation (i.e. the angular difference in degrees between the rotation of the head and pelvis) and head-pelvis velocity were analyzed using Wilcoxon signed-rank tests. During slow walking, turning velocity was 15% lower accompanied by shorter step length and longer step time compared to comfortable walking. Reducing walking speed also led to a decrease in the amplitude and velocity of the axial rotation of the head and pelvis as well as a reduced head-pelvis separation and angular velocity. This study demonstrates that axial coordination during turning is speed dependent as evidenced by a more 'en bloc' movement pattern (i.e. less separation between axial segments) at reduced speeds in healthy older adults. This emphasizes the need for matching speed when comparing groups with diverse walking speeds to differentiate changes due to speed from changes due to disease. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. [Myopia: frequency of lattice degeneration and axial length].

    Science.gov (United States)

    Martín Sánchez, M D; Roldán Pallarés, M

    2001-05-01

    To evaluate the relationship between lattice retinal degeneration and axial length of the eye in different grades of myopia. A sample of 200 eyes from 124 myopic patients was collected by chance. The average age was 34.8 years (20-50 years) and the myopia was between 0.5 and 20 diopters (D). The eyes were grouped according to the degree of refraction defect, the mean axial length of each group (Scan A) and the frequency of lattice retinal degeneration and the relationship between these variables was studied. The possible influence of age on our results was also considered. For the statistical analysis, the SAS 6.07 program with the variance analysis for quantitative variables, and chi(2) test for qualitative variables with a 5% significance were used. A multivariable linear regression model was also adjusted. The highest frequency of lattice retinal degeneration occurred in those myopia patients having more than 15 D, and also in the group of myopia patients between 3 and 6 D, but this did not show statistical significance when compared with the other myopic groups. If the axial length is assessed, a greater frequency of lattice retinal degeneration is also found when the axial length is 25-27 mm and 29-30 mm, which correspond, respectively, to myopias between 3-10 D and more than 15 D. When the multivariable linear regression model was adjusted, the axial length showed the existence of lattice retinal degeneration (beta 0.41 mm; p=0.08) adjusted by the number of diopters (beta 0.38 mm; plattice retinal degeneration was found for myopias with axial eye length between 29-30 mm (more than 15 D), and 25-27 mm (between 3-10 D).

  15. Axial Permanent Magnet Generator for Wearable Energy Harvesting

    DEFF Research Database (Denmark)

    Högberg, Stig; Sødahl, Jakob Wagner; Mijatovic, Nenad

    2016-01-01

    An increasing demand for battery-free electronics is evident by the rapid increase of wearable devices, and the design of wearable energy harvesters follows accordingly. An axial permanent magnet generator was designed to harvest energy from human body motion and supplying it to a wearable...... application. The design was approached from an lectromagnetic point of view in this article. Two types of axial flux permanent magnet generators were designed: one with an iron yoke, which is commonly used to reduce the machine volume and demand of permanent magnets, and a second without the iron yoke...

  16. Manufacture of axially insulated large-area diodes

    International Nuclear Information System (INIS)

    Ma Weiyi; Zhou Kungang; Wang Youtian; Zhang Dong; Shan Yusheng; Wang Naiyan

    1999-01-01

    The author describes the design and construction of the axially insulated large-area diodes used in the 'Heaven-1'. The four axially insulated large-area diodes are connected to the 10 ohm pulse transmission lines via the vacuum feed through tubes. The experimental results with the diodes are given. The diodes can steadily work at the voltage of 650 kV, and the diode current density is about 80 A per cm 2 with a pulse width of 220 ns. The electron beams with a total energy of 25 kJ are obtained

  17. Periodicity effects of axial waves in elastic compound rods

    DEFF Research Database (Denmark)

    Nielsen, R. B.; Sorokin, S. V.

    2015-01-01

    Floquet analysis is applied to the Bernoulli-Euler model for axial waves in a periodic rod. Explicit asymptotic formulae for the stop band borders are given and the topology of the stop band pattern is explained. Eigenfrequencies of the symmetric unit cell are determined by the Phase-closure Prin......Floquet analysis is applied to the Bernoulli-Euler model for axial waves in a periodic rod. Explicit asymptotic formulae for the stop band borders are given and the topology of the stop band pattern is explained. Eigenfrequencies of the symmetric unit cell are determined by the Phase...

  18. Buckling localization in a cylindrical panel under axial compression

    DEFF Research Database (Denmark)

    Tvergaard, Viggo; Needleman, A.

    2000-01-01

    Localization of an initially periodic buckling pattern is investigated for an axially compressed elastic-plastic cylindrical panel of the type occurring between axial stiffeners on cylindrical shells. The phenomenon of buckling localization and its analogy with plastic flow localization in tensile...... test specimens is discussed in general. For the cylindrical panel, it is shown that buckling localization develops shortly after a maximum load has been attained, and this occurs for a purely elastic panel as well as for elastic-plastic panels. In a case where localization occurs after a load maximum...

  19. Spectral analysis in thin tubes with axial heterogeneities

    KAUST Repository

    Ferreira, Rita

    2015-01-01

    In this paper, we present the 3D-1D asymptotic analysis of the Dirichlet spectral problem associated with an elliptic operator with axial periodic heterogeneities. We extend to the 3D-1D case previous 3D-2D results (see [10]) and we analyze the special case where the scale of thickness is much smaller than the scale of the heterogeneities and the planar coefficient has a unique global minimum in the periodic cell. These results are of great relevance in the comprehension of the wave propagation in nanowires showing axial heterogeneities (see [17]).

  20. A simple approach to the ABJ axial anomaly

    International Nuclear Information System (INIS)

    Horejsi, J.

    1985-01-01

    A very simple semi-quantitative derivation of the Adler-Bell-Jackiw (ABJ) axial anomaly is given, based on an investigation of the absorptive part of the VVA triangle graph and dispersion relations. Essential ingredients of our discussion are: normal Ward identities for the absorptive part of the relevant diagram, dimensional analysis, unitarity, and energy-momentum conservation. An explanation of the physical origin of axial anomaly, proposed in some earlier treatments within such a dispersive framework, is critically examined. In particular, the interpretation of the ABJ anomaly as an analogy of the Lee-Nauenberg effect occurring in the massless limit of spinor electrodynamics is shown to be fallacious

  1. Light-front view of the axial anomaly

    International Nuclear Information System (INIS)

    Ji, C.; Rey, S.

    1996-01-01

    Motivated by an apparent puzzle of the light-front vacua incompatible with the axial anomaly, we have considered the two-dimensional massless Schwinger model for an arbitrary interpolating angle of Hornbostel close-quote s interpolating quantization surface. By examining spectral deformation of the Dirac sea under an external electric field semiclassically, we have found that the axial anomaly is quantization angle independent. This indicates an intricate nontrivial vacuum structure present even in the light-front limit. copyright 1996 The American Physical Society

  2. Study on Predicting Axial Load Capacity of CFST Columns

    Science.gov (United States)

    Ravi Kumar, H.; Muthu, K. U.; Kumar, N. S.

    2017-11-01

    This work presents an analytical study and experimental study on the behaviour and ultimate load carrying capacity of axially compressed self-compacting concrete-filled steel tubular columns. Results of tests conducted by various researchers on 213 samples concrete-filled steel tubular columns are reported and present authors experimental data are reported. Two theoretical equations were derived for the prediction of the ultimate axial load strength of concrete-filled steel tubular columns. The results from prediction were compared with the experimental data. Validation to the experimental results was made.

  3. Computed tomographic myelography (CTM) in atlanto-axial rheumatoid arthritis

    International Nuclear Information System (INIS)

    Laasonen, E.M.; Servo, A.; Kankaanpaeae, U.; Paukku, P.; Sandelin, J.; Slaetis, P.

    1985-01-01

    Thirty-two patients with severe cervical rheumatoid arthritis were investigated preoperatively with cervical myelography (CeM) and computed tomographic myelography (CTM). The severity of their clinical symptoms correlated excellently with a combination of the deformation of the spinal cord at the atlanto-axial level, the lateral dislocation of the cord at the same level, and the deformation of the cord at some lower cervical level. Obstructing softtissue excrescences seemed to have little value. No correlation was found in this study between the deformation of the cord and the main findings of the plain films: the atlanto-axial subluxation (AAS), the vertical subluxation (VS), or their combination. (orig.)

  4. Lesões traumáticas do parênquima pulmonar: aspectos na tomografia computadorizada Traumatic lung lesions: computed tomography findings

    Directory of Open Access Journals (Sweden)

    Alessandro Severo Alves de Melo

    2003-06-01

    Full Text Available As lesões pulmonares são achados freqüentes no trauma torácico, sendo cada vez mais diagnosticadas pela tomografia computadorizada, em especial pelo rápido tempo de aquisição decorrente da técnica helicoidal, que permite a avaliação de pacientes em estado grave, possibilitando a adoção de conduta terapêutica eficiente. Os autores estudaram 150 pacientes vítimas de trauma torácico submetidos a tomografia computadorizada, que apresentaram lesões pulmonares, representadas por contusões, atelectasias, lacerações e hematomas pulmonares. As contusões pulmonares se caracterizaram por consolidações e atenuação em vidro fosco, sendo as lesões pulmonares mais comuns. As atelectasias foram observadas com os padrões subsegmentar e compressiva, e foram a segunda lesão mais comum. As lacerações se apresentaram como consolidações com ar ou nível líquido no interior. Os hematomas pulmonares representaram a lesão pulmonar mais rara, presentes em apenas cinco casos, caracterizados por opacidades arredondadas. Neste trabalho o trauma torácico fechado predominou, com 120 casos, enquanto o trauma aberto ocorreu em 30 casos. As causas de trauma fechado, em ordem decrescente de freqüência, foram: colisão automobilística, atropelamento, queda de altura, acidente de motocicleta e espancamento. A forma penetrante de traumatismo torácico decorreu de duas causas de agressão: lesão por arma de fogo e lesão por arma branca.Traumatic lesions of the lung are common findings in patients with thoracic trauma. These lesions are increasingly diagnosed using computed tomography, mostly due to the fast acquisition time helical techniques that allow evaluation of critically ill patients and an efficient therapeutic management. The authors studied 150 patients with thoracic trauma submitted to computed tomography that demonstrated lung contusions, atelectasies, lacerations and hematomas. Lung contusions were the most frequent lesions

  5. Aspectos da tomografia computadorizada no linfoma em pacientes abaixo de 20 anos de idade Computed tomography findings in patients less than 20 years old with lymphoma

    Directory of Open Access Journals (Sweden)

    Adriana Moreira Viana Borba

    2007-04-01

    Full Text Available OBJETIVO: Descrever os achados gerais do linfoma em pacientes abaixo de 20 anos de idade e por subtipo histológico. MATERIAIS E MÉTODOS: Estudo retrospectivo do arquivo digital de tomografia computadorizada do Centro de Controle do Câncer do Hospital Universitário Pedro Ernesto da Universidade do Estado do Rio de Janeiro, no período de março de 2003 a julho de 2005. Dos 22 casos - 16 do sexo masculino e 6 do sexo feminino, com média de idade de 11,5 anos -, 12 eram do subtipo Hodgkin e 10 eram não-Hodgkin. RESULTADOS: Dos achados gerais, verificamos as linfonodomegalias mediastinais como o mais freqüente (59%, com predomínio no grupo Hodgkin (75%, seguido por hepatoesplenomegalia (50% e linfonodomegalias cervicais e retroperitoneais (27,3%. No subtipo Hodgkin houve predomínio do acometimento linfonodal, em sucessivas cadeias, seguido pela hepatoesplenomegalia (50%. Verificamos um caso de massa tonsilar unilateral, opacidade pulmonar em "vidro-fosco" e nódulos renais. No subtipo não-Hodgkin houve predomínio extranodal caracterizado por hepatoesplenomegalia (50%, espessamento de alça intestinal (40%, derrame pleural (30%, nódulo pulmonar (20%, ascite (10%, derrame pericárdico (10% e lesões ósseas mistas (10%. CONCLUSÃO: A tomografia computadorizada é de grande valia no diagnóstico, estadiamento e seguimento do linfoma, com achados de alerta como massa linfonodal, notadamente mediastinal, hepatoesplenomegalia, massa unilateral na tonsila e espessamento parietal de alça intestinal.OBJECTIVE: To describe the general findings of lymphoma and their histological patterns in patients less than 20 years old. MATERIALS AND METHODS: Twenty-two cases (16 male and 6 female, mean age 11.5 years from the digital archive of computed tomography at the Cancer Control Center of "Hospital Universitário Pedro Ernesto - Universidade do Estado do Rio de Janeiro", Rio de Janeiro, RJ, Brazil, were retrospectively analyzed in the period between

  6. O valor da fase sem contraste na tomografia computadorizada do abdome The role of the unenhanced phase in the routine abdominal computed tomography

    Directory of Open Access Journals (Sweden)

    Ana Paula Klautau Leite

    2008-10-01

    Full Text Available OBJETIVO: Determinar o valor agregado da fase sem meio de contraste da tomografia computadorizada do abdome em pacientes sem diagnóstico determinado ou em estadiamento tumoral. MATERIAIS E MÉTODOS: Estudo prospectivo e transversal em 100 pacientes consecutivos submetidos a tomografia computadorizada abdominal sem e com meio de contraste intravenoso. Dois examinadores avaliaram todos os exames, procurando estabelecer, através da fase com meio de contraste intravenoso (primeira análise e posteriormente através da fase sem contraste (segunda análise, o diagnóstico principal e os secundários em função da indicação clínica do exame. Mediu-se a freqüência de mudança diagnóstica decorrente da análise combinada das fases pré- e pós-contraste intravenoso. Casos que tiveram mudança diagnóstica foram avaliados por especialistas clínicos para determinar se implicaria mudanças de conduta. RESULTADOS: Diagnósticos principal e secundário foram modificados em 1 e 18 casos, respectivamente (p = 1,000; p = 0,143. Os diagnósticos modificados foram: esteatose, definição de nódulo em adrenal, nefrolitíase, classificação de cistos renais e calcificação hepática. Nos casos em que a fase sem contraste modificou o diagnóstico, os especialistas mudaram sua conduta em 14/19 (73% dos pacientes (p = 0,038. CONCLUSÃO: A fase sem contraste não modificou significativamente o diagnóstico principal ou secundário. Porém, as mudanças nos diagnósticos secundários influenciaram na conduta adotada pelos especialistas.OBJECTIVE: To determine the role of the unenhanced phase of abdominal computed tomography in patients without a definite diagnosis or undergoing tumor staging. MATERIALS AND METHODS: A prospective and transversal study was developed with 100 consecutive patients submitted to unenhanced and contrast-enhanced abdominal computed tomography. Two observers evaluated all the computed tomography images in the contrast-enhanced phase

  7. Linfangioliomiomatose pulmonar: aspectos na tomografia computadorizada de alta resolução Pulmonary lymphangioleiomyomatosis: high-resolution computed tomography findings

    Directory of Open Access Journals (Sweden)

    Eduardo Curty Castro Netto

    2003-08-01

    Full Text Available Neste trabalho foram estudados, retrospectivamente, 17 pacientes com linfangioliomiomatose pulmonar diagnosticada por biópsia pulmonar a céu aberto. Todos os pacientes eram do sexo feminino, com idade média de 39,6 anos. Duas pacientes tiveram também o diagnóstico de esclerose tuberosa. As pacientes foram submetidas a tomografia computadorizada de alta resolução, cujos achados revelaram cistos com conteúdo gasoso, de formas variadas e com diferentes tamanhos, não ultrapassando 60 mm de diâmetro. A grande maioria tinha as paredes finas. Todos os cistos apresentaram distribuição difusa pelo parênquima pulmonar. Somente duas pacientes apresentaram pneumotórax associado. Nódulos parenquimatosos e espessamento de septos interlobulares não foram observados. Dessa forma, as características tomográficas utilizadas para o diagnóstico foram a ausência de nódulos e a presença de cistos de tamanhos variados, em geral menores que 20 mm, arredondados e distribuídos difusamente pelo parênquima pulmonar.We reviewed 17 cases of pulmonary lymphangioleiomyomatosis diagnosed by open lung biopsy. All patients were women with a mean age of 39.6 years. Tuberous sclerosis was diagnosed in two cases. The patients were submitted to high-resolution computed tomography that showed diffuse thin walled cystic lesions of less than 60 mm in diameter. Associated pneumothorax was seen in two cases. The main high-resolution computed tomography findings were diffuse, rounded, cystic lesions, generally of less than 20 mm in diameter.

  8. Hemorragia subaracnoídea com tomografia de crânio sem sinais de sangramento Subarachnoidal hemorrhage with cranial tomography without bleeding signals

    Directory of Open Access Journals (Sweden)

    Silvio Francisco

    1997-09-01

    Full Text Available Foram observados 23 casos de pacientes com suspeita clínica de hemorragia subaracnoídea (HSA, com tomografia de crânio (CT sem sinais de sangramento, com diagnóstico definitivo realizado por exame de líquido cefalorraquiano(LCR. Desses, 20 casos foram submetidos a angiografia cerebral. Estabeleceu-se a classificação clínica de Hunt & Hess. Os principais achados neste estudo foram:1 um terço dos pacientes apresentou intervalo de tempo entre o ictus e a realização da CT e do LCR entre 24 e 48 horas, período de maior sensiblidade da CT; 2 dos pacientes estudados com angiografia cerebral, 55% tiveram o diagnóstico de aneurisma com predomínio no território de carótida e cerebral anterior; 3 o grau clínico dominante foi Hunt & Hess I e II. Todos os achados encontrados demonstraram a necessidade da realização de LCR em suspeita de HSA sem sinais de sangramento na CT.We observed 23 pacients with clinical hypothesis of subarachnoidal hemorrhage (SAH having cranial tomography (CT without bleeding signals. The final diagnosis of SAH was made upon the cerebrospinal fluid (CSF results. Twenty cases were submitted to brain angiography. They were focused under the clinical classification of Hunt & Hess. The main results were: 1 1/3 of patients had interval time between 24 and 48 hours after ictus and before CT and CSF making; this was the most sensitive CT time; 2 55% of patients with brain angiography had aneurysm predominantly in the carotid and anterior cerebral artery territory; 3 the dominant clinical degree was Hunt & Hess I e II. Conclusion: the results demonstrate the need of CSF test in case of SAH clinical diagnosis with CT showing no bleeding signals.

  9. Quantificação das grandezas dosimétricas em exames de tomografia computadorizada pediátricos do abdome

    Directory of Open Access Journals (Sweden)

    Tiago da Silva Jornada

    2014-10-01

    Full Text Available Objetivo: Visando contribuir para o conhecimento das doses em tomografia computadorizada (TC, este trabalho teve o objetivo de quantificar grandezas dosimétricas associadas a exames do abdome em pacientes pediátricos, comparando-as com os níveis de referência em radiodiagnóstico (NRD. Materiais e métodos: O estudo foi realizado em dois hospitais, em um tomógrafo Toshiba Asteion single-slice e um GE BrightSpeed multi-slice. Medidas foram feitas com uma câmara de ionização tipo lápis e um objeto simulador de tronco de polimetilmetacrilato de 16 cm de diâmetro. Resultados: Os valores do índice ponderado de kerma no ar (CW não apresentaram diferenças significativas, porém, para as grandezas índice de kerma no ar volumétrico (CVOL, produto kerma-comprimento (PKL,CT e dose efetiva, as diferenças foram relevantes. Conclusão: Apenas o CW apresentou valores menores que os NRD, sugerindo que a otimização não seria necessária. Porém, os valores de PKL,CT e dose efetiva mostraram que há espaço para reduzir as doses de radiação pediátricas. Este trabalho ressalta a importância de avaliar todas as grandezas dosimétricas associadas aos exames por TC.

  10. Trauma dos ossos temporais e suas complicações: aspectos na tomografia computadorizada Temporal bone trauma and complications: computed tomography findings

    Directory of Open Access Journals (Sweden)

    Ana Maria Doffémond Costa

    2013-04-01

    Full Text Available A maioria das fraturas dos ossos temporais resulta de traumas cranianos bruscos, de alta energia, estando muitas vezes relacionadas a outras fraturas cranianas ou a politraumatismo. As fraturas e os deslocamentos da cadeia ossicular, na orelha média, representam umas das principais complicações das injúrias nos ossos temporais e, por isso, serão abordadas de maneira mais profunda neste artigo. Os outros tipos de injúrias englobam as fraturas labirínticas, fístula dural, paralisia facial e extensão da linha de fratura ao canal carotídeo. A tomografia computadorizada tem papel fundamental na avaliação inicial dos pacientes politraumatizados, pois é capaz de identificar injúrias em importantes estruturas que podem causar graves complicações, como perda auditiva de condução ou neurossensorial, tonturas e disfunções do equilíbrio, fístulas perilinfáticas, paralisia do nervo facial, lesões vasculares, entre outras.Most temporal bone fractures result from high-energy blunt head trauma, and are frequently related to other skull fractures or to polytrauma. Fractures and displacements of ossicular chain in the middle ear represent some of the main complications of temporal bone injury, and hence they will be more deeply approached in the present article. Other types of injuries include labyrinthine fractures, dural fistula, facial nerve paralysis and extension into the carotid canal. Computed tomography plays a fundamental role in the initial evaluation of polytrauma patients, as it can help to identify important structural injuries that may lead to severe complications such as sensorineural hearing loss, conductive hearing loss, dizziness and balance dysfunction, perilymphatic fistulas, facial nerve paralysis, vascular injury and others.

  11. Redesigning axial-axial (biaxial) cruciform specimens for very high cycle fatigue ultrasonic testing machines.

    Science.gov (United States)

    Montalvão, Diogo; Wren, Andrew

    2017-11-01

    The necessity to increase performances in terms of lifetime and security in mechanical components or structures is the motivation for intense research in fatigue. Applications range from aeronautics to medical devices. With the development of new materials, there is no longer a fatigue limit in the classical sense, where it was accepted that the fatigue limit is the stress level such that there is no fracture up to 1E7 cycles. The recent development of ultrasonic testing machines where frequencies can go as high as 20 kHz or over enabled tests to be extended to ranges larger than 1E9 in just a few days. This area of studies is now known as Very High Cycle Fatigue (VHCF). On the other hand, most of the existing test equipment in the market for both classical and VHCF are uniaxial test machines. However, critical components used in Engineering applications are usually subjected to complex multi-axial loading conditions. In this paper, it is presented the methodology to redesigning existing cruciform test specimens that can be used to create an in-plane biaxial state of stress when used in 'uniaxial' VHCF ultrasonic testing machines (in this case, the term 'uniaxial' is used not because of the state of stress created at the centre of the specimen, but because of the direction at which the load is applied). The methodology is explained in such a way that it can be expanded to other existing designs, namely cruciform designs, that are not yet used in VHCF. Also, although the approach is presented in simple and logical terms, it may not be that obvious for those who have a more focused approach on fatigue rather than on modal analysis. It is expected that by contributing to bridging the gap between the sciences of modal analysis and fatigue, this research will help and encourage others exploiting new capabilities in VHCF.

  12. New molecular targets for PET and SPECT imaging in neurodegenerative diseases Novos alvos moleculares para tomografia por emissão de pósitrons (PET e tomografia computadorizada por emissão de fóton único (SPECT em doenças neurodegenerativas

    Directory of Open Access Journals (Sweden)

    Marcel Benadiba

    2012-10-01

    Full Text Available The pathophysiology of neurodegenerative diseases (ND such as Alzheimer's disease (AD and Parkinson's disease (PD has not yet been completely elucidated. However, in the past few years, there have been great knowledge advances about intra-and extracellular proteins that may display impaired function or expression in AD, PD and other ND, such as amyloid beta (Aβ, α-synuclein, tau protein and neuroinflammatory markers. Recent developments in the imaging techniques of positron emission tomography (PET and single photon emission computed tomography (SPECT now allow the non-invasive tracking of such molecular targets of known relevance to ND in vivo. This article summarizes recent findings of PET and SPECT studies using these novel methods, and discusses their potential role in the field of drug development for ND as well as future clinical applications in regard to differential diagnosis of ND and monitoring of disease progression.A fisiopatologia das doenças neurodegenerativas (DN, tais como a doença de Alzheimer (DA e a doença de Parkinson (DP, ainda não é completamente compreendida. No entanto, nos últimos anos, houve grandes avanços em termos do conhecimento sobre proteínas intra e extracelulares, tais como beta-amiloide (Aβ, α-sinucleína, proteína tau e marcadores neuroinflamatórios, que podem ter sua função ou expressão prejudicada na DA, DP ou em outras DN. Progressos recentes nas técnicas de tomografia por emissão de pósitrons (PET e tomografia computadorizada por emissão de fóton único (SPECT permitem hoje em dia a identificação não invasiva de tais alvos moleculares in vivo. Este artigo resume descobertas recentes de estudos de PET e SPECT cerebral usando esses alvos moleculares inovadores e discute o papel potencial dessas técnicas no campo do desenvolvimento de novos medicamentos para as DN, bem como futuras aplicações clínicas em relação ao diagnóstico diferencial e monitoramento da progressão dessas

  13. Supersymmetric axial anomalies and the Wess-Zumino action

    International Nuclear Information System (INIS)

    Harada, K.; Shizuya, K.

    1988-01-01

    We derive, by an algebraic method, a manifestly supersymmetric extension of Bardeen's minimal form of axial anomalies, which obeys the Wess-Zumino consistency condition. The left-right symmetric form of the anomalies is also obtained by a reduction procedure. We construct the supersymmetric Wess-Zumino effective action and study its low-energy features. (orig.)

  14. Dynamic Response of Axially Loaded Euler-Bernoulli Beams

    DEFF Research Database (Denmark)

    Bayat, M.; Barari, Amin; Shahidi, M.

    2011-01-01

    The current research deals with application of a new analytical technique called Energy Balance Method (EBM) for a nonlinear problem. Energy Balance Method is used to obtain the analytical solution for nonlinear vibration behavior of Euler-Bernoulli beams subjected to axial loads. Analytical...

  15. Axial Torsion of Gangrenous Meckel's Diverticulum Causing Small ...

    African Journals Online (AJOL)

    dividing the band. Resection and anastomosis of the small bowel including the MD was performed. We hereby report a rare and unusual complication of a MD. Although treatment outcome is generally good, pre-operative diagnosis is often difficult. Key words: Axial torsion, Meckel's diverticulum, small bowel obstruction.

  16. A cylindrical drift chamber with azimuthal and axial position readout

    Energy Technology Data Exchange (ETDEWEB)

    Bar-Yam, Z.; Cummings, J.P.; Dowd, J.P.; Eugenio, P.; Hayek, M.; Kern, W.; King, E.; Shenhav, N.; Chung, S.U.; Hackenburg, R.W.; Olchanski, C.; Weygand, D.P.; Willutzki, H.J.; Brabson, B.B.; Crittenden, R.R.; Dzierba, A.R.; Gunter, J.; Lindenbusch, R.; Rust, D.R.; Scott, E.; Smith, P.T.; Sulanke, T.; Teige, S.; Denisov, S.; Dushkin, A.; Kochetkov, V.; Lipaev, V.; Popov, A.; Shein, I.; Soldatov, A.; Anoshina, E.V.; Bodyagin, V.A.; Demianov, A.I.; Gribushin, A.M.; Kodolova, O.L.; Korotkikh, V.L.; Kostin, M.A.; Ostrovidov, A.I.; Sarycheva, L.I.; Sinev, N.B.; Vardanyan, I.N.; Yershov, A.A.; Adams, T.; Bishop, J.M.; Cason, N.M.; Sanjari, A.H.; LoSecco, J.M.; Manak, J.J.; Shephard, W.D.; Stienike, D.L.; Taegar, S.A.; Thompson, D.R.; Brown, D.S.; Pedlar, T.; Seth, K.K.; Wise, J.; Zhao, D.; Adams, G.S.; Napolitano, J.; Nozar, M.; Smith, J.A.; Witkowski, M. [Massachusetts Univ., North Dartmouth, MA (United States)]|[Brookhaven National Laboratory, Upton, L.I., NY 11973 (United States)]|[Indiana University, Bloomington, IN 47405 (United States)]|[Institute for High Energy Physics, Protvino (Russian Federation)]|[Institute of Nuclear Physics, Moscow State University, Moscow (Russian Federation)]|[University of Notre Dame, Notre Dame, IN 46556 (United States)]|[Northwestern University, Evanston, IL 60208 (United States)]|[Rensselaer Polytechnic Institute, Troy, NY 12180 (United States)

    1997-02-21

    A cylindrical multiwire drift chamber with axial charge-division has been constructed and used in experiment E852 at Brookhaven National Laboratory. It serves as a trigger element and as a tracking device for recoil protons in {pi}{sup -}p interactions. We describe the chamber`s design considerations, details of its construction, electronics, and performance characteristics. (orig.).

  17. Studi Regangan Axial dan Lateral pada Tanah Ekspansif

    Directory of Open Access Journals (Sweden)

    Lisa Fitriyana

    2017-07-01

    Full Text Available Swelling and shrinkage abilities of soils are dangerous for buildings. According to Hardiyatmo (2014 There are two types of swelling in expansive soils that are the movement of lateral (horizontal and axial (vertical. Oftentimes the deformation of soils cannot be supported by building stiffness. This damage can be seen in retaining walls, tunnel walls, and etc. With the aims to identify an expansive soil and to know its lateral and axial strains, an experimental study was performed. Swelling tests were conducted in a specimen having diameter (d of 4,5 cm and height (h0 of 2 cm with the variations in : 1 water content wopt = 31% and 18%; 2 vertical pressure (pv 1 kPa, 3.5 kPa and 6.9 kPa; and 3 membrane thickness (t 0.7 mm and 0.5 mm. The strain in the axial direction was measured with a dial gauge that was set vertically parallel whereas the lateral strain is by measuring changes in diameter of the specimen with a digital caliper measurement tools. Based on the analysis on the identification results, the observed soil is classified as expansive soil with the expansion potential is high average. The test results show the same potential for the occurrence of lateral and lateral strain if the lateral retention (e.g. retaining wall is weak. The largest lateral and axial soil development occurred at water content w0 = 18% are 15.7% and 15.8% respectively.

  18. Axial-Gap Induction Motor For Levitated Specimens

    Science.gov (United States)

    Sridharan, Govind; Rhim, Won-Kyu; Barber, Dan; Chung, Sang

    1992-01-01

    Motor does not obscure view of specimen. Axial-gap induction motor applies torque to rotate electrostatically or electromagnetically levitated specimen of metal. Possible applications include turning specimens for uniform heating under focused laser beams and obtaining indirect measurements of resistivities or of surface tensions in molten specimens.

  19. On aspects of vibration of axially moving continua

    NARCIS (Netherlands)

    Hageraats-Ponomareva, S.

    2009-01-01

    In axially moving structures like conveyor belt systems, magnetic tapes, and so on, vibrations occur due to the presence of different kinds of imperfections in the systems. For these structures internal resonances can lead to severe vibrations. Resonance free conveyor belt systems can be constructed

  20. Axial Length/Corneal Radius of Curvature Ratio and Refractive ...

    African Journals Online (AJOL)

    2017-12-05

    Dec 5, 2017 ... variously described as determined by the ocular biometric variables. There have been many studies on the relationship between refractive error and ocular axial length (AL), anterior chamber depth, corneal radius of curvature (CR), keratometric readings as well as other ocular biometric variables such as ...

  1. Solution of the gauge identities in the axial gauge

    International Nuclear Information System (INIS)

    Delbourgo, R.

    1981-01-01

    Starting from the spectral representation of the two-point functions in the axial gauge, the gauge identities are solved so as to express the higher-point Green functions linearly in terms of the two-point spectral function. The four-point functions are an important input for investigations of scalar electrodynamics and vector chromodynamics based on the gauge technique. (author)

  2. 3-D Simulation of Vertical-Axial Tidal Current Turbine

    Directory of Open Access Journals (Sweden)

    Zhiyang Zhang

    2016-12-01

    Full Text Available Vertical-axial tidal current turbine is the key for the energy converter, which has the advantages of simple structure, adaptability to flow and uncomplex convection device. It has become the hot point for research and application recently. At present, the study on the hydrodynamic performance of vertical-axial tidal current turbine is almost on 2-D numerical simulation, without the consideration of 3-D effect. CFD (Computational Fluid Dynamics method and blade optimal control technique are used to improve accuracy in the prediction of tidal current turbine hydrodynamic performance. Numerical simulation of vertical-axial tidal current turbine is validated. Fixed and variable deflection angle turbine are comparatively studied to analysis the influence of 3-D effect and the character of fluid field and pressure field. The method, put the plate on the end of blade, of reduce the energy loss caused by 3-D effect is proposed. The 3-D CFD numerical model of vertical-axial tidal current turbine hydrodynamic performance in this study may provide theoretical, methodical and technical reference for the optimal design of turbine.

  3. View of the Axial Field Spectrometer (R807)

    CERN Multimedia

    1980-01-01

    In this view of the Axial Field Spectrometer at I8, the vertical uranium/scintillator hadron calorimeter (just left of centre) is retracted to give access to the cylindrical central drift chamber. The yellow iron structure served as a filter to identify muons, with MWPCs and the array of Cherenkov counters to the right.

  4. Landforms along transverse faults parallel to axial zone of folded ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 126; Issue 1. Landforms along transverse faults parallel to axial zone of folded mountain front, north-eastern Kumaun Sub-Himalaya, India. Khayingshing ... Keywords. Himalayan Frontal Thrust; outer Kumaun Himalaya; transverse structure; folded mountain front.

  5. sizing of wind powered axial flux permanent magnet alternator using

    African Journals Online (AJOL)

    user

    2016-10-04

    Oct 4, 2016 ... Using analytical calculations, the design parameters of the alternator's main dimensions were obtained in a ... SIZING OF WIND POWERED AXIAL FLUX PERMANENT MAGNET ALTERNATOR USING ANALYTICAL APPROACH,. A. O. Otuoze, et al .... then be expressed as. Equation (7) can be re-written as.

  6. Evaluation of electromagnetic shielding effectiveness of multi-axial ...

    Indian Academy of Sciences (India)

    Abstract. The usage of electrical and electronic equipments has been increasing in daily life, which has a potential hazardous impact on humans and other living organisms. In this paper, multi-axial fabrics containing steel yarns and carbon filaments, and their polyester (PES) resin-reinforced composites have been ...

  7. Ocular Axial Length and Keratometry Readings of Normal Eyes in ...

    African Journals Online (AJOL)

    Aim: To provide average axial length and keratometry readings in healthy eyes of people in Rivers and surrounding states in southern Nigeria. This may guide the purchase of intraocular lens in the study area. Materials and methods: Four hundred consecutive patients with 800 non-cataractous eyes attending the eye clinic ...

  8. Axial drive to nonlinear flow between rotating cylinders

    Science.gov (United States)

    Ashrafi, Nariman; Hazbavi, Abbas

    2014-02-01

    Stability of pseudoplastic rotational flow between cylinders in presence of an independent axial component is investigated. The fluid is assumed to follow the Carreau model and mixed boundary conditions are imposed. The conservation of mass and momentum equations give rise to a four-dimensional low-order dynamical system, including additional nonlinear terms in the velocity components originated from the shear-dependent viscosity. In absence of the axial flow, as the pseudoplasticity effects increases, the purely-azimuthal base flow loses its stability to the vortex structure at a lower critical Taylor number. Emergence of the vortices corresponds to the onset of a supercritical bifurcation also present in the flow of a linear fluid. However, unlike the Newtonian case, pseudoplastic Taylor vortices lose their stability as the Taylor number reaches a second critical number corresponding to the onset of a Hopf bifurcation. Existence of an axial flow induced by a pressure gradient appears to further advance each critical point on the bifurcation diagram. In continuation, complete flow field together with viscosity maps is analyzed for different flow scenarios. Through evaluation of the Lyapunov exponent, flow stability and temporal behavior of the system for cases with and without axial flow are brought to attention.

  9. Employing a tri-axial accelerometer for estimating energy ...

    African Journals Online (AJOL)

    The Tritrac-R3D, a portable tri-axial accelerometer, was assessed for its ability to estimate energy expenditure during simulated load carrying activities. The Tritrac data were compared to metabolic data collected simultaneously by a MetaMax ergospirometry system while ten, healthy male subjects (aged 20.7 ±1.4 years) ...

  10. Numerical simulation of breakup and detachment of an axially ...

    Indian Academy of Sciences (India)

    Kishore Singh Patel

    Abstract. The extensional, breakup and detachment dynamics of an axially stretching Newtonian liquid bridge are investigated numerically with a dynamic domain multiphase incompressible flow solver. The mul- tiphase flow solver employs a Cahn–Hilliard phase field model to describe the evolution of the diffuse interface.

  11. Computation of the lateral and axial point spread functions in ...

    Indian Academy of Sciences (India)

    ... confocal scanning microscopes for the above-mentioned amplitude filters. These results of axial and lateral irradiances are graphically represented by constructing a computer program using MATLAB. The obtained results are compared with that obtained in case of circular, annular, and Martinez-Corral apodized aperture ...

  12. Axial Length/Corneal Radius of Curvature Ratio and Refractive ...

    African Journals Online (AJOL)

    2018-02-07

    Feb 7, 2018 ... Aim/Background: Associations between axial length (AL) to corneal radius of curvature (CR) ratio and refractive status in a healthy Nigerian adult population were studied. Materials and Methods: Healthy students and members of staff of Obafemi Awolowo Teaching Hospitals Complex, Ile-Ife, South West ...

  13. Axial heterogeneous core concept applied for super phoenix reactor

    International Nuclear Information System (INIS)

    Batista, J.L.; Renke, C.A.C.; Waintraub, M.; Santos Bastos, W. dos; Brito Aghina, L.O. de.

    1991-11-01

    Always maintaining the current design rules, this paper presents a parametric study on the type of axial heterogeneous core concept (CHA), utilizing a core of fast reactor Super Phenix type, reaching a maximum thermal burnup rate of 150000 M W d/t and being managed in single batch. (author)

  14. Fission gas retention and axial expansion of irradiated metallic fuel

    International Nuclear Information System (INIS)

    Fenske, G.R.; Emerson, J.E.; Savoie, F.E.; Johanson, E.W.

    1986-05-01

    Out-of-reactor experiments utilizing direct electrical heating and infrared heating techniques were performed on irradiated metallic fuel. The results indicate accelerated expansion can occur during thermal transients and that the accelerated expansion is driven by retained fission gases. The results also demonstrate gas retention and, hence, expansion behavior is a function of axial position within the pin

  15. Evaluation of electromagnetic shielding effectiveness of multi-axial ...

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... ... Lecture Workshops · Refresher Courses · Symposia. Home; Journals; Bulletin of Materials Science; Volume 39; Issue 4. Evaluation of electromagnetic shielding effectiveness of multi-axial fabrics and their reinforced PES composites. RAMAZAN ERDEM. Volume 39 Issue 4 August 2016 pp 963-970 ...

  16. Evaluation of electromagnetic shielding effectiveness of multi-axial ...

    Indian Academy of Sciences (India)

    The usage of electrical and electronic equipments has been increasing in daily life, which has a potential hazardous impact on humans and other living organisms. In this paper, multi-axial fabrics containing steel yarns and carbon filaments, and their polyester (PES) resin-reinforced composites have been prepared for ...

  17. Elevated temperature axial and torsional fatigue behavior of Haynes 188

    Science.gov (United States)

    Bonacuse, Peter J.; Kalluri, Sreeramesh

    1995-01-01

    The results are reported for high-temperature axial and torsional low-cycle fatigue experiments performed at 760 C in air on thin-walled tubular specimens of Haynes 188, a wrought cobalt-based superalloy. Data are also presented for mean coefficient of thermal expansion, elastic modulus, and shear modulus at various temperatures from room to 1000 C, and monotonic and cyclic stress-strain curves in tension and in shear at 760 C. This data set is used to evaluate several multiaxial fatigue life models (most were originally developed for room temperature multiaxial life prediction) including von Mises equivalent strain range (ASME Boiler and Pressure Code), Manson-Halford, modified multiaxiality factor (proposed in this paper), modified Smith-Watson-Topper, and Fatemi-Socie-Kurath. At von Mises equivalent strain ranges (the torsional strain range divided by the square root of 3, taking the Poisson's ratio to be 0.5), torsionally strained specimens lasted, on average, factors of 2 to 3 times longer than axially strained specimens. The modified multiaxiality factor approach shows promise as a useful method of estimating torsional fatigue life from axial fatigue data at high temperatures. Several difficulties arose with the specimen geometry and extensometry used in these experiments. Cracking at extensometer probe indentations was a problem at smaller strain ranges. Also, as the largest axial and torsional strain range fatigue tests neared completion, a small amount of specimen buckling was observed.

  18. first principles derivation of a stress function for axially symmetric

    African Journals Online (AJOL)

    HOD

    found to be identical with the Love stress function. The stress function was then applied to solve the axially symmetric problem of finding the stress fields, strain fields and displacement fields in the semi-infinite linear elastic, isotropic homogeneous medium subject to a point load P acting at the origin of coordinates also ...

  19. Kinetics and equilibria for the axial ligation of bromomethyl (aqua ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 121; Issue 6. Kinetics and equilibria for the axial ligation of bromomethyl (aqua)cobaloxime with pyridines - Isolation characterization and DNA binding. Kotha Laxma Reddy K Ashwini Kumar N Ravi Kumar Reddy Penumaka Nagababu A Panasa Reddy S ...

  20. Axial anomaly and magnetism of nuclear and quark matter

    Science.gov (United States)

    Son, D. T.; Stephanov, M. A.

    2008-01-01

    We consider the response of the QCD ground state at finite baryon density to a strong magnetic field B. We point out the dominant role played by the coupling of neutral Goldstone bosons, such as π0, to the magnetic field via the axial triangle anomaly. We show that, in vacuum, above a value of B˜mπ2/e, a metastable object appears—the π0 domain wall. Because of the axial anomaly, the wall carries a baryon number surface density proportional to B. As a result, for B≳1019G a stack of parallel π0 domain walls is energetically more favorable than nuclear matter at the same density. Similarly, at higher densities, somewhat weaker magnetic fields of order B≳1017 1018G transform the color-superconducting ground state of QCD into new phases containing stacks of axial isoscalar (η or η') domain walls. We also show that a quark-matter state known as “Goldstone current state,” in which a gradient of a Goldstone field is spontaneously generated, is ferromagnetic due to the axial anomaly. We estimate the size of the fields created by such a state in a typical neutron star to be of order 1014 1015G.

  1. Modelling the cardiac transverse-axial tubular system

    Czech Academy of Sciences Publication Activity Database

    Pásek, Michal; Šimurda, J.; Christé, G.; Orchard, C.

    2008-01-01

    Roč. 96, - (2008), s. 226-246 ISSN 0079-6107 Institutional research plan: CEZ:AV0Z20760514 Keywords : cardiac cell * transverse-axial tubular system * quantitative modelling Subject RIV: BO - Biophysics Impact factor: 6.388, year: 2008

  2. Comparison of design methods for axially loaded buckets in sand

    DEFF Research Database (Denmark)

    Vaitkunaite, Evelina; Nielsen, Benjaminn Nordahl; Ibsen, Lars Bo

    2015-01-01

    A study of the present knowledge about the bucket resistance for axial loading was performed considering analytical and numerical design methods as well as physical models. A case study was performed with two bucket foundations of equal diameter, but different skirt lengths installed in dense san...

  3. Axial and focal-plane diffraction catastrophe integrals

    International Nuclear Information System (INIS)

    Berry, M V; Howls, C J

    2010-01-01

    Exact expressions in terms of Bessel functions are found for some of the diffraction catastrophe integrals that decorate caustics in optics and mechanics. These are the axial and focal-plane sections of the elliptic and hyperbolic umbilic diffraction catastrophes, and symmetric elliptic and hyperbolic unfoldings of the X 9 diffraction catastrophes. These representations reveal unexpected relations between the integrals.

  4. Atlanto-axial instability in rheumatoid arthritis: a review | Omar ...

    African Journals Online (AJOL)

    Objectives: The purpose of this literature review is to identify common lesions present in the rheumatoid neck with specific emphasis to atlanto-axial instability, review its clinical presentation, imaging findings and management. Study design: A review of the English medical literature was done with focus on recent studies ...

  5. Axial Length/Corneal Radius of Curvature Ratio and Refractive ...

    African Journals Online (AJOL)

    Aim/Background: Associations between axial length (AL) to corneal radius of curvature (CR) ratio and refractive status in a healthy Nigerian adult population were studied. Materials and Methods: Healthy students and members of staff of Obafemi Awolowo Teaching Hospitals Complex, Ile‑Ife, South West Nigeria, free of ...

  6. Ocular Axial Length Measurement Among Normal Adults Using ...

    African Journals Online (AJOL)

    2017-07-26

    Jul 26, 2017 ... Background/Introduction: Macrophthalmia and microphthalmia are cardinal signs of many orbito-ocular and systemic diseases which are seen in northern Nigeria. Some cases of refractive error may also be directly related to the ocular axial length (AL). The need for an imaging parameter that will aid their ...

  7. Axial Torsion of Gangrenous Meckel's Diverticulum Causing Small ...

    African Journals Online (AJOL)

    Meckel's diverticulum (MD) is a commonly encountered congenital anomaly of the small intestine. We report an extremely unusual case of an axially torted, gangrenous MD presenting as acute intestinal obstruction. A 26-year-old male patient presented to our emergency department with 3 days history of abdominal pain, ...

  8. Computation of the lateral and axial point spread functions in ...

    Indian Academy of Sciences (India)

    scanning microscopes for the above-mentioned amplitude filters. These results of axial and lateral irradiances are graphically represented by constructing a computer program using MATLAB. The obtained results are compared with that obtained in case of circular, annular, and Martinez-Corral apodized aperture. Keywords ...

  9. Fatigue Limit of Axially Compressed Concrete | Levchich | Nigerian ...

    African Journals Online (AJOL)

    An attempt to evaluate analytically the fatigue limit of axially loaded concrete depending upon the load parameters, number of load cycles and static short-term strength is presented. The conventional limit of concrete microcracking statical sustained strength of concrete, curvelinear relationship between fatigue limit and load ...

  10. Severe vertical atlanto-axial subluxation in rheumatoid arthritis

    Directory of Open Access Journals (Sweden)

    Sílvia Fernandes

    2015-01-01

    Full Text Available The authors present the imaging study of a case of severe vertical atlanto-axial subluxation in a 60-year-old male with long-term rheumatoid arthritis with severe polyarticular involvement (Class IV of Steinbrocker functional classification.

  11. Report on the Dynamical Evolution of an Axially Symmetric Quasar ...

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... The role of the angular momentum in the regular or chaotic character of motion in an axially symmetric quasar model is examined. It is found that, for a given value of the critical angular momentum , there are two values of the mass of the nucleus for which transition from regular to chaotic motion ...

  12. Report on the Dynamical Evolution of an Axially Symmetric Quasar ...

    Indian Academy of Sciences (India)

    Abstract. The role of the angular momentum in the regular or chaotic character of motion in an axially symmetric quasar model is examined. It is found that, for a given value of the critical angular momentum Lzc, there are two values of the mass of the nucleus Mn for which transition from regular to chaotic motion occurs.

  13. Axial-flow fan with eccentric rotor | Blaho | Zede Journal

    African Journals Online (AJOL)

    Axial-flow fan with eccentric rotor. M Blaho. Abstract. No Abstract. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use · Contact AJOL · News. OTHER RESOURCES... for Researchers · for Journals ...

  14. Infecção pulmonar pelo Rhodococcus equi na síndrome da imunodeficiência adquirida: Aspectos na tomografia computadorizada Rhodococcus equi infection in acquired immunodeficiency syndrome: Computed tomography aspects

    Directory of Open Access Journals (Sweden)

    Edson Marchiori

    2006-10-01

    Full Text Available OBJETIVO: Apresentar os aspectos na tomografia computadorizada da pneumonia pelo Rhodococcus equi em sete pacientes com síndrome da imunodeficiência adquirida. MÉTODOS: Estudo retrospectivo das tomografias de sete pacientes com síndrome da imunodeficiência adquirida e infecção pelo Rhodococcus equi. RESULTADOS: Os achados mais freqüentes foram: consolidação (n = 7 com escavação (n = 6, opacidades em vidro fosco (n = 6, nódulos do espaço aéreo (n = 4 e nódulos centrolobulares com árvore em brotamento (n = 3. CONCLUSÃO: Os achados mais comuns na infecção pulmonar pelo Rhodococcus equi em pacientes com síndrome da imunodeficiência adquirida foram as consolidações escavadas.OBJECTIVE: To present the computed tomography aspects of Rhodococcus equi pneumonia in seven patients with acquired immunodeficiency syndrome. METHODS: A retrospective study of the computed tomography scans of seven patients with acquired immunodeficiency syndrome and Rhodococcus equi infection. RESULTS: The most common findings were consolidation (n = 7, consolidation with cavitation (n = 6, ground glass opacities (n = 6, peribronchial nodules (n = 4 and centrilobular nodules presenting a "tree-in-bud" pattern (n = 3. CONCLUSION: The most common finding in patients with Rhodococcus equi pulmonary infection and acquired immunodeficiency syndrome was consolidation with cavitation.

  15. Sinais de uretelolitíase na tomografia computadorizada helicoidal sem contraste: ensaio iconográfico e revisão de literatura Ureterolithiasis signs on unenhanced helical computed tomography: iconographic essay and literature review

    Directory of Open Access Journals (Sweden)

    Renata La Rocca Vieira

    2004-12-01

    Full Text Available O principal sinal diagnóstico de ureterolitíase na tomografia computadorizada é a visualização direta do cálculo no interior do ureter. Todavia, a sua caracterização pode ser prejudicada devido a suas pequenas dimensões, variação da respiração entre a aquisição dos cortes tomográficos, escassez de gordura retroperitoneal ou eliminação recente do cálculo. Neste contexto, foram descritos diversos sinais secundários de obstrução ureteral, observados na tomografia computadorizada, que podem auxiliar no diagnóstico de casos duvidosos, além de quantificar o grau de obstrução urinária.The most important diagnostic sign of ureterolithiasis is the direct visualization of the stone within the ureter. However, in some patients with ureterolithiasis stone visualization may be impaired due to stone small size or low attenuation, respiratory artifacts between data acquisitions, low amount of retroperitoneal fat or recent elimination of the stone. In this context, we describe many secondary computed tomography signs of ureteral obstruction that may useful in the diagnosis of inconclusive cases, and also quantify the degree of urinary obstruction.

  16. Determinação das coordenadas na tomografia computadorizada estereotáxica: simplificação do método convencional Determination of the coordinates in the stereotactic computed tomography: simplification of the conventional method

    Directory of Open Access Journals (Sweden)

    Sebastião Silva Gusmão

    2002-09-01

    Full Text Available Apresenta-se uma simplificação dos métodos gráfico e aritmético usualmente utilizados para determinação das coordenadas estereotáxicas de um alvo na tomografia computadorizada. O cálculo aritmético, além de mais simples, é teoricamente mais preciso por medir as coordenadas do alvo a partir de um ponto real do espaço estereotáxico. O diagrama (método gráfico proposto apresenta a vantagem de permitir a determinação das coordenadas estereotáxicas do alvo independentemente do tamanho das imagens da tomografia computadorizada.A simplification of the graphic and arithmetical method traditionally used for determination of the target stereotactic coordinates in the computed tomography is presented. The arithmetical calculation, besides simpler, is theoretically more accurate for using a real point of the stereotactic space. The proposed diagram (graphic method presents the advantage of allowing the determination of the target stereotactic coordinates independently of the computed tomographic image size.

  17. Fração de ejeção e volumes do ventrículo esquerdo medidos com eco 3D e com tomografia ultra-rápida Fracción de eyección y volúmenes del ventrículo izquierdo medidos con eco- 3DTR y con tomografía ultrarrápida Left ventricular ejection fraction and volumes as measured by 3d echocardiography and ultrafast computed tomography

    Directory of Open Access Journals (Sweden)

    Marcelo Luiz Campos Vieira

    2009-04-01

    Full Text Available FUNDAMENTO: O ecocardiograma tridimensional em tempo real (ECO 3D e a tomografia computadorizada ultra-rápida (CT são dois novos métodos de análise da fração de ejeção e dos volumes do VE. OBJETIVO: Comparar as medidas da FEVE e dos volumes do VE aferidos pelo ECO 3D e pela CT ultra-rápida. MÉTODOS: Foram estudados pelo ECO 3D e pela CT ultra-rápida de 64 cortes, 39 pacientes consecutivos (27 homens, média etária de 57±12 anos. Foram analisados: FEVE e volumes do VE. Análise estatística: coeficiente de correlação (r: Pearson, teste de Bland & Altman, teste de regressão linear, 95 % IC, pFUNDAMENTO: La ecocardiografía tridimensional en tiempo real (Eco-3DTR y la tomografía computarizada ultrarrápida (TC ultrarrápida son dos nuevos métodos de análisis de la fracción de eyección (FE y de los volúmenes del ventrículo izquierdo (VI. OBJETIVO: Comparar las mediciones de la fracción de eyección del ventrículo izquierdo (FEVI y de los volúmenes del VI apurados por la Eco-3DTR y por la TC ultrarrápida. MÉTODOS: Se estudiaron, mediante la Eco-3DTR y la TC ultrarrápida de 64 cortes, a 39 pacientes consecutivos (27 varones, promedio de edad de 57±12 años. Se analizaron: FEVI y volúmenes del VI. Análisis estadístico: coeficiente de correlación (r: Pearson, prueba de Bland & Altman, prueba de regresión lineal, 95 % IC, pBACKGROUND: Real-time three-dimensional echocargiography (RT-3D-Echo and ultrafast computed tomography (CT are two novel methods for the analysis of LV ejection fraction and volumes. OBJECTIVE: To compare LVEF and volume measurements as obtained using RT-3D-Echo and ultrafast CT. METHODS: Thirty nine consecutive patients (27 men, mean age of 57±12 years were studied using RT-3D-Echo and 64-slice ultrafast CT. LVEF and LV volumes were analyzed. Statistical analysis: coefficient of correlation (r: Pearson, Bland-Altman analysis, linear regression analysis, 95% CI, p<0.05. RESULTS: RT-3D

  18. The Nucleon Axial Form Factor and Staggered Lattice QCD

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Aaron Scott [Chicago U.

    2017-01-01

    The study of neutrino oscillation physics is a major research goal of the worldwide particle physics program over the upcoming decade. Many new experiments are being built to study the properties of neutrinos and to answer questions about the phenomenon of neutrino oscillation. These experiments need precise theoretical cross sections in order to access fundamental neutrino properties. Neutrino oscillation experiments often use large atomic nuclei as scattering targets, which are challenging for theorists to model. Nuclear models rely on free-nucleon amplitudes as inputs. These amplitudes are constrained by scattering experiments with large nuclear targets that rely on the very same nuclear models. The work in this dissertation is the rst step of a new initiative to isolate and compute elementary amplitudes with theoretical calculations to support the neutrino oscillation experimental program. Here, the eort focuses on computing the axial form factor, which is the largest contributor of systematic error in the primary signal measurement process for neutrino oscillation studies, quasielastic scattering. Two approaches are taken. First, neutrino scattering data on a deuterium target are reanalyzed with a model-independent parametrization of the axial form factor to quantify the present uncertainty in the free-nucleon amplitudes. The uncertainties on the free-nucleon cross section are found to be underestimated by about an order of magnitude compared to the ubiquitous dipole model parametrization. The second approach uses lattice QCD to perform a rst-principles computation of the nucleon axial form factor. The Highly Improved Staggered Quark (HISQ) action is employed for both valence and sea quarks. The results presented in this dissertation are computed at physical pion mass for one lattice spacing. This work presents a computation of the axial form factor at zero momentum transfer, and forms the basis for a computation of the axial form factor momentum dependence

  19. Axial SPN and radial MOC coupled whole core transport calculation

    International Nuclear Information System (INIS)

    Cho, Jin-Young; Kim, Kang-Seog; Lee, Chung-Chan; Zee, Sung-Quun; Joo, Han-Gyu

    2007-01-01

    The Simplified P N (SP N ) method is applied to the axial solution of the two-dimensional (2-D) method of characteristics (MOC) solution based whole core transport calculation. A sub-plane scheme and the nodal expansion method (NEM) are employed for the solution of the one-dimensional (1-D) SP N equations involving a radial transverse leakage. The SP N solver replaces the axial diffusion solver of the DeCART direct whole core transport code to provide more accurate, transport theory based axial solutions. In the sub-plane scheme, the radial equivalent homogenization parameters generated by the local MOC for a thick plane are assigned to the multiple finer planes in the subsequent global three-dimensional (3-D) coarse mesh finite difference (CMFD) calculation in which the NEM is employed for the axial solution. The sub-plane scheme induces a much less nodal error while having little impact on the axial leakage representation of the radial MOC calculation. The performance of the sub-plane scheme and SP N nodal transport solver is examined by solving a set of demonstrative problems and the C5G7MOX 3-D extension benchmark problems. It is shown in the demonstrative problems that the nodal error reaching upto 1,400 pcm in a rodded case is reduced to 10 pcm by introducing 10 sub-planes per MOC plane and the transport error is reduced from about 150 pcm to 10 pcm by using SP 3 . Also it is observed, in the C5G7MOX rodded configuration B problem, that the eigenvalues and pin power errors of 180 pcm and 2.2% of the 10 sub-planes diffusion case are reduced to 40 pcm and 1.4%, respectively, for SP 3 with only about a 15% increase in the computing time. It is shown that the SP 5 case gives very similar results to the SP 3 case. (author)

  20. Non-steroidal anti-inflammatory drugs (NSAIDs) for axial spondyloarthritis (ankylosing spondylitis and non-radiographic axial spondyloarthritis)

    NARCIS (Netherlands)

    Kroon, Feline P. B.; van der Burg, Lennart R. A.; Ramiro, Sofia; Landewé, Robert B. M.; Buchbinder, Rachelle; Falzon, Louise; van der Heijde, Désirée

    2015-01-01

    Axial spondyloarthritis (axSpA) comprises ankylosing spondylitis (radiographic axSpA) and non-radiographic (nr-)axSpA and is associated with psoriasis, uveitis and inflammatory bowel disease. Non-steroidal anti-inflammatory drugs (NSAIDs) are recommended as first-line drug treatment. To determine

  1. Two-dimensional nonlinear dynamics of an axially moving viscoelastic beam with time-dependent axial speed

    International Nuclear Information System (INIS)

    Ghayesh, Mergen H.; Amabili, Marco; Farokhi, Hamed

    2013-01-01

    In the present study, the coupled nonlinear dynamics of an axially moving viscoelastic beam with time-dependent axial speed is investigated employing a numerical technique. The equations of motion for both the transverse and longitudinal motions are obtained using Newton’s second law of motion and the constitutive relations. A two-parameter rheological model of the Kelvin–Voigt energy dissipation mechanism is employed in the modelling of the viscoelastic beam material, in which the material time derivative is used in the viscoelastic constitutive relation. The Galerkin method is then applied to the coupled nonlinear equations, which are in the form of partial differential equations, resulting in a set of nonlinear ordinary differential equations (ODEs) with time-dependent coefficients due to the axial acceleration. A change of variables is then introduced to this set of ODEs to transform them into a set of first-order ordinary differential equations. A variable step-size modified Rosenbrock method is used to conduct direct time integration upon this new set of first-order nonlinear ODEs. The mean axial speed and the amplitude of the speed variations, which are taken as bifurcation parameters, are varied, resulting in the bifurcation diagrams of Poincaré maps of the system. The dynamical characteristics of the system are examined more precisely via plotting time histories, phase-plane portraits, Poincaré sections, and fast Fourier transforms (FFTs)

  2. Reprodutibilidade das mensurações da espessura das tábuas ósseas na tomografia computadorizada Cone-Beam utilizando diferentes protocolos de aquisição de imagem Reproducibility of bone plate thickness measurements with Cone-Beam Computed Tomography using different image acquisition protocols

    Directory of Open Access Journals (Sweden)

    Carolina Carmo de Menezes

    2010-10-01

    Full Text Available INTRODUÇÃO: quanto menor a dimensão do voxel, maior a nitidez da imagem de tomografia computadorizada Cone-Beam (TCCB, porém, maior a dose de radiação emitida. OBJETIVOS: avaliar e comparar a reprodutibilidade da mensuração da espessura das tábuas ósseas vestibular e lingual em imagens de TCCB, utilizando diferentes protocolos de aquisição de imagem com variação da dimensão do voxel. MÉTODOS: exames de TCCB foram tomados de 12 mandíbulas humanas secas, com dimensão do voxel de 0,2; 0,3 e 0,4mm, no aparelho i-CAT Cone-Beam 3-D Dental Imaging System. No software i-CAT Viewer, foi mensurada a espessura das tábuas ósseas vestibular e lingual, em um corte axial passando 12mm acima do forame mentoniano do lado direito. A reprodutibilidade intraexaminador foi avaliada por meio da aplicação do teste t pareado. Para a comparação interexaminadores, foi utilizado o teste t independente. Os resultados foram considerados com o nível de significância de 5%. RESULTADOS: observou-se uma excelente reprodutibilidade interexaminadores para os três protocolos avaliados. A reprodutibilidade intraexaminadores foi muito boa, com exceção de algumas regiões dos dentes anteriores, que mostraram diferenças estatisticamente significativas, independentemente da dimensão do voxel. CONCLUSÃO: a mensuração da espessura das tábuas ósseas vestibular e lingual em imagens de TCCB mostrou boa precisão para exames obtidos com voxel de 0,2; 0,3 ou 0,4mm. A reprodutibilidade das mensurações na região anterior da mandíbula foi mais crítica do que na região posterior.INTRODUCTION: A smaller voxel dimension leads to greater resolution of Cone-Beam Computed Tomography (CBCT, but a greater dosage of radiation is emitted. OBJECTIVE: Assess and compare the reproducibility of buccal and lingual bone plate thickness measurements in CBCT images using different image acquisition protocols, with variations in the voxel dimension. METHODS: CBCT exams

  3. Axial segregation in spherical and cylindrical rotating tumblers

    Directory of Open Access Journals (Sweden)

    D’Ortona Umberto

    2017-01-01

    Full Text Available Monodisperse and bidisperse granular flows are studied in rotating tumblers using DEM. In spherical tumblers, flowing particles’ trajectories do not follow straight lines but are curved. At the same time particles near the surface drift toward the pole, inducing two global recirculation cells. Combined with radial segregation, drift and curvature compete to impose the axial segregation pattern: Small-Large-Small (SLS or Large-Small-Large (LSL. Fill level, rotation speed and wall roughness influence drift and curvature, and modify the resulting segregation pattern. In cylindrical tumblers, equivalent recirculation cells occur next to the end walls. A second pair of recirculation cells with a weak drift in the opposite direction appears at the center for long enough tumblers. Unlike the sphere case, curvature and drift in the primary cells combine to push large particles toward the end walls, explaining why large particle bands appear at the end walls for axial segregation in cylinder.

  4. Classical theory of the Kumakhov radiation in axial channeling

    International Nuclear Information System (INIS)

    Khokonov, M.K.; Komarov, F.F.; Telegin, V.I.

    1984-01-01

    The paper considers radiation of ultrarelativistic electrons in axial channeling initially predicted by Kumakhov. The consideration is based on the results of solution of the Fokker-Planck equation. The spectral-angular characteristics of the Kumakhov radiation in thick single crystals are calculated. It is shown that in heavy single crystals the energy losses on radiation can amount to a considerable portion of the initial beam energy. The possibility of a sharp increase of radiation due to a decrease of crystal temperature is discussed. It is shown that radiation intensity in axial channeling is weakly dependent on the initial angle of the electron entrance into the channel if this angle changes within the limits of a critical one. (author)

  5. Impaired bed mobility: quantitative torque analysis with axial inertial sensors.

    Science.gov (United States)

    Bhidayasiri, Roongroj; Sringean, Jirada; Thanawattano, Chusak

    2017-08-01

    Difficulty in turning in bed is rated as the most troublesome night-time symptom among Parkinson's disease (PD) patients. To develop a practical objective method for home assessment of a patient's ability to turn in bed. Nocturnal parameters and torque of self-turning in bed from 17 PD couples were assessed and compared using a wearable axial sensor for two nights in their homes. The torque of axial rotation which indicates the ability of PD patients to turn in bed was significantly less than their spouses (p turning in bed and total unified Parkinson's Disease Rating Scale score (r = 0.71; p = 0.001), and total Nocturnal Akinesia Dystonia and Cramp score (r = 0.634; p = 0.006). Our study confirms a decreased ability in turning in PD.

  6. Vector and axial nucleon form factors: A duality constrained parameterization

    International Nuclear Information System (INIS)

    Bodek, A.; Avvakumov, S.; Bradford, R.; Budd, H.

    2008-01-01

    We present new parameterizations of vector and axial nucleon form factors. We maintain an excellent descriptions of the form factors at low momentum transfers, where the spatial structure of the nucleon is important, and use the Nachtman scaling variable ξ to relate elastic and inelastic form factors and impose quark-hadron duality constraints at high momentum transfers where the quark structure dominates. We use the new vector form factors to re-extract updated values of the axial form factor from neutrino experiments on deuterium. We obtain an updated world average value from ν μ d and pion electroproduction experiments of M A =1.014±0.014 GeV/c 2 . Our parameterizations are useful in modeling neutrino interactions at low energies (e.g. for neutrino oscillations experiments). The predictions for high momentum transfers can be tested in the next generation electron and neutrino scattering experiments. (orig.)

  7. Computerized axial tomography : the tool in osseointegrated dental implants

    International Nuclear Information System (INIS)

    Fernandez-Lopez, Otton

    2002-01-01

    Failure rates in rehabilitations with osseointegrated implants are handled through appropriate radiographic preoperative planning. The appropriate length of the implant without running the risk of a perforation of vital structures, has been determined by a radiographic diagnosis. Computerized and conventional axial tomography have proved to be invaluable elements for pre-surgical evaluation. A radiologic guidance is elaborated to perform a computerized axial tomography (CT) of maxillary bones in totally edentulous patients. Surgical guides are constructed from a wax-up emanated from the information of the CT. The CT has proven to be an radiographic indispensable element to achieve the surgical-prosthetic success in osseointegrated dental implants. The CT has allowed the realization of a precise wax-up for making of surgical guide and a precise temporary prostheses in positioning of osseointegrated implants, with the consequent saving time and money for the rehabilitator and patient [es

  8. [Inflammatory spinal diseases: axial spondyloarthritis : Central importance of imaging].

    Science.gov (United States)

    Baraliakos, X; Fruth, M; Kiltz, U; Braun, J

    2017-03-01

    The diagnosis of axial spondyloarthritis (axSpA) includes classical ankylosing spondylitis (AS) as well as earlier stages and abortive courses of the disease, in which structural alterations have not yet occurred. These are classified as non-radiographic axSpA (nr-axSpa). Inflammatory changes in the entire axial skeleton are characteristic for axSpA and can be visualized by magnetic resonance imaging (MRI), while in most patients structural alterations, such as new bone formation with syndesmophytes and ankylosis develop in the later course of the disease. These bony alterations can best be visualized by conventional radiography and by computed tomography. Certain MRI sequences are nowadays considered as the standard method for depiction of inflammatory changes in axSpA. The introduction of MRI has led to a paradigm shift for this disease because the inflammatory lesions characteristic for the disease can be visualized at an early stage using appropriate MRI sequences.

  9. Organocatalyzed Asymmetric Synthesis of Axially, Planar, and Helical Chiral Compounds.

    Science.gov (United States)

    Shirakawa, Seiji; Liu, Shiyao; Kaneko, Shiho

    2016-02-04

    Axially, planar, and helical chiral compounds are indispensable building blocks in modern organic synthesis. A wide variety of chiral ligands and catalysts were designed based on these chiral scaffolds, and these chiral ligands and catalysts were used for various catalytic asymmetric transformations to produce important chiral compounds in an optically enriched form. Furthermore, these chiral skeletons are found in the structure of biologically active natural products. Thus, the development of efficient enantioselective methods for the synthesis of these chiral compounds is an important task in the field of organic chemistry. In the last few years, organocatalyzed approaches, which are one of the most reliable catalytic asymmetric methods, became a hot topic. This Focus Review summarizes asymmetric organocatalytic methods for the synthesis of axially, planar, and helical chiral compounds as useful chiral building blocks. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. An Axial Sliding Test for machine elements surfaces

    DEFF Research Database (Denmark)

    Godi, Alessandro; Grønbæk, J.; Mohaghegh, Kamran

    2012-01-01

    are necessary: a press to provide the normal pressure and a tensile machine to perform the axial movements. The test is calibrated so that the correspondence between the normal pressure and the container advancement is found. Finally, preliminary tests are carried out involving a multifunctional and a fine......Throughout the years, it has become more and more important to find new methods for reducing friction and wear occurrence in machine elements. A possible solution is found in texturing the surfaces under tribological contact, hence the development and spread of plateau-honed surface for cylinder...... liners. To prove the efficacy of a particular textured surface, it is paramount to perform experimental tests under controlled laboratory conditions. In this paper a new test rig simulating pure sliding conditions is presented, dubbed Axial Sliding Test. It presents four major components: a rod, a sleeve...

  11. Axial positrons emission tomography: from mouse to human brain imaging

    International Nuclear Information System (INIS)

    Brard, Emmanuel

    2013-01-01

    Positrons emission tomography is a nuclear imaging technics using nuclear decays. It is used both in clinical and preclinical studies. The later requires the use of small animals such as the mouse. The objective is to obtain the best signal with the best spatial resolution. Yet, a weight ratio between humans and mice indicates the need of a sub-millimeter resolution. A conventional scanner is based on detection modules surrounding the object to image and arranged perpendicularly. This implies a strong relationship between efficiency and spatial resolution. This work focuses on the axial geometry in which detection modules are arranged parallel to the object. This limits the relationship between the figures of merit, leading to both high spatial resolution and efficiency. The simulations of prototypes showed great perspectives in term of sub-millimeter resolution with efficiencies of 15 or 40% according to the scanner's axial extension. These results indicate great perspectives for both clinical and preclinical imaging. (author)

  12. Buckling Imperfection Sensitivity of Axially Compressed Orthotropic Cylinders

    Science.gov (United States)

    Schultz, Marc R.; Nemeth, Michael P.

    2010-01-01

    Structural stability is a major consideration in the design of lightweight shell structures. However, the theoretical predictions of geometrically perfect structures often considerably over predict the buckling loads of inherently imperfect real structures. It is reasonably well understood how the shell geometry affects the imperfection sensitivity of axially compressed cylindrical shells; however, the effects of shell anisotropy on the imperfection sensitivity is less well understood. In the present paper, the development of an analytical model for assessing the imperfection sensitivity of axially compressed orthotropic cylinders is discussed. Results from the analytical model for four shell designs are compared with those from a general-purpose finite-element code, and good qualitative agreement is found. Reasons for discrepancies are discussed, and potential design implications of this line of research are discussed.

  13. Involvement of the axial skeleton in psoriatic arthritis

    Directory of Open Access Journals (Sweden)

    E. E. Gubar

    2017-01-01

    Full Text Available The involvement of the spine in psoriatic arthritis (PsA is observed in a large number of cases; however, a unified approach to solving this problem has not yet been formed. Criteria for the diagnosis of psoriatic spondylitis have not been clearly defined; internationally accepted definitions for this concept are absent; criteria for a PsA exacerbation and remission have not been formulated with regard to spondylitis. The specialists of GRAPPA (Group for Research and Assessment of Psoriasis and Psoriatic Arthritis have no their own recommendations for the treatment of axial involvement in PsA now. The therapeutic tactics used in the treatment of axial spondylitis and ankylosing spondylitis is borrowed in this area. The involvement of the spine calls for further investigation.

  14. Axial Ge/Si nanowire heterostructure tunnel FETs

    Energy Technology Data Exchange (ETDEWEB)

    Picraux, Sanuel T [Los Alamos National Laboratory; Daych, Shadi A [Los Alamos National Laboratory

    2010-01-01

    The vapor-liquid-solid (VLS) growth of semiconductor nanowires allows doping and composition modulation along their axis and the realization of axial 1 D heterostructures. This provides additional flexibility in energy band-edge engineering along the transport direction which is difficult to attain by planar materials growth and processing techniques. We report here on the design, growth, fabrication, and characterization of asymmetric heterostructure tunnel field-effect transistors (HTFETs) based on 100% compositionally modulated Si/Ge axial NWs for high on-current operation and low ambipolar transport behavior. We discuss the optimization of band-offsets and Schottky barrier heights for high performance HTFETs and issues surrounding their experimental realization. Our HTFET devices with 10 nm PECVD SiN{sub x} gate dielectric resulted in a measured current drive exceeding 100 {mu}A/{mu}m (I/{pi}D) and 10{sup 5} I{sub on}/I{sub off} ratios.

  15. Buckling localization in a cylindrical panel under axial compression

    DEFF Research Database (Denmark)

    Tvergaard, Viggo; Needleman, A.

    2000-01-01

    Localization of an initially periodic buckling pattern is investigated for an axially compressed elastic-plastic cylindrical panel of the type occurring between axial stiffeners on cylindrical shells. The phenomenon of buckling localization and its analogy with plastic flow localization in tensile...... test specimens is discussed in general. For the cylindrical panel, it is shown that buckling localization develops shortly after a maximum load has been attained, and this occurs for a purely elastic panel as well as for elastic-plastic panels. In a case where localization occurs after a load maximum......, but where subsequently the load starts to increase again, it is found that near the local load minimum, the buckling pattern switches back to a periodic type of pattern. The inelastic material behavior of the panel is described in terms of J(2) corner theory, which avoids the sometimes unrealistically high...

  16. Accuracy Improvement of Axial Power Shape Reconstruction Using GMDH Algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Yum, Seongpil; Kim, Jaemin; Park, Minyong; Choe, Jiwon; Zhang, Peng; Lee, Deokjung [UNIST, Ulsan (Korea, Republic of); Shin, Ho Cheol [KHNP CRI, Daejeon (Korea, Republic of)

    2016-10-15

    This paper applies Group Method of Data Handling (GMDH) algorithm to improve the reconstruction accuracy. Reference three-dimensional power distributions are generated for Shinkori Unit 1 Cycle 3 by simulating Xe transients in BOC, MOC, and EOC, which include saddle, top- and bottom-skewed shapes. Using these power distributions, the axial power distributions were reconstructed by GMDH and the 5th order Fourier series method. It was shown that GMDH algorithm reduced the average Root-Mean-Square-Error (RMSE) from 1.01% of Fourier series method, down to 0.17%. This paper presents the accuracy improvement of axial power reconstruction using GMDH algorithm with the first order polynomial basis function compared to the COLSS Fourier series expansion algorithm.

  17. Axial weak currents in the Wess-Zumino term

    International Nuclear Information System (INIS)

    Fujikawa, Kazuo

    1986-01-01

    In a simplified model lagrangian of 3 quarks with an SU(2)sub(L) gauging of chiral SU(3)sub(L)xSU(3)sub(R) to introduce W-boson, we analyse certain complications associated with the low-energy theorem including axial weak fields. We first show that the low-energy amplitude is independent of the form of the quark-level anomalous identity, whether in the covariant form or the consistent form. However, the interplay of the short-distance dynamics (anomalous identity) and the long-distance dynamics (low-energy theorem) becomes involved in the presence of axial fields. We then discuss what kinds of conditions single out the gauged Wess-Zumino term as a low-energy effective action. The connection of the low-energy theorem with the 't Hooft anomaly matching condition is also discussed. (orig.)

  18. Dynamics of tubular cylindrical structures in axial flow.

    OpenAIRE

    Paidoussis, Michael P.

    2017-01-01

    The dynamics of slender cylinders in axial flow subject to conventional boundary conditions is recalled first. This is followed by brief reviews and discussion of new developments in (i) the dynamics of unconventionally supported cylinders, e.g. cylinders free at the upstream end and supported at the downstream one, (ii) the dynamics of cylinders subject to both internal and external flow for applications in oil and gas drilling and production, as well as hydrocarbon storage in salt-mined cav...

  19. Experimental investigations on an axial grooved cryogenic heat pipe

    Directory of Open Access Journals (Sweden)

    Senthil Kumar Muniappan

    2012-01-01

    Full Text Available This paper deals with development and studies of a trapezoidal axial grooved nitrogen heat pipe. A special liquid nitrogen cryostat has been designed and developed for evaluating the performance of heat pipe where the condenser portion is connected to the cold sink externally. Experiments have been performed on the heat pipe as well as on an equivalent diameter copper rod at different heat loads. The steady state performance of the heat pipe is compared with that of copper rod.

  20. Axially symmetric domain wall in 2+1-dimensions

    International Nuclear Information System (INIS)

    Soda, Jiro; Yamanaka, Yuki.

    1991-04-01

    An axially symmetric domain wall (string) in 2+1-dimensions is investigated in the synchronous gauge. This problem is also regarded as a cylindrical symmetric domain wall (membrane) in 3+1-dimensions. Using Israel's method, we present a general solution. As a special case, a static solution is obtained which agrees with the previous result of Deser and Jackiw obtained by another method. (author)

  1. Axially symmetric, stationary gravitational field equations and pseudospherical surfaces

    International Nuclear Information System (INIS)

    Tomimatsu, Akira.

    1981-04-01

    For axially symmetric, stationary gravitational field equations, a new Lax pair of the inverse scattering method is presented from a geometrical point of view. The metric coefficient e sup(2γ) (= -g sub(rho rho)g sub(tt)sup(-1)) is taken as the basic field variable, which satisfies an equation describing pseudospherical surfaces, i.e., surfaces of constant negative Gaussian curvature. The equations for other metric coefficients are also discussed. (author)

  2. Overview of the Axial Field Spectrometer in the ISR tunnel

    CERN Multimedia

    1980-01-01

    A view of the Axial Field Spectrometer – the last large experiment at the ISR. The horizontal top and vertical outer arrays of the uranium-scintillator hadron calorimeter are clear to be seen, with the blue cylindrical pole piece of the magnet just visible. The pipes that are visible in front of the pole piece are cryogenic feed pipes for the superconducting low-beta quadrupoles.

  3. Channel of Axial Injection of DC-60 Cyclotron

    CERN Document Server

    Gikal, B N; Bogomolov, S L; Borisenko, A N; Borisov, O N; Gulbekyan, G G; Ivanenko, I A; Kalagin, I V; Kazacha, V I; Kazarinov, N Yu; Khabarov, M V; Lysukhin, S N; Melnikov, V N; Paschenko, S V; Tikhomirov, A V

    2006-01-01

    The design study and realization of the axial injection beam line of DC-60 cyclotron constructed at the Flerov Laboratory of Nuclear Reactions of the Joint Institute for Nuclear Research are given. The channel allows one to transport and to inject into the cyclotron ions with mass-to-charge ratio $A/Z$ being within interval A/Z=6-12 and kinetic energy up to 17 $Z/A$ keV/m.u.

  4. Colonic surveillance by CT colonography using axial images only

    International Nuclear Information System (INIS)

    Bruzzi, John F.; Brennan, Darren D.; Fenlon, Helen M.; Moss, Alan C.; MacMathuna, Padraic

    2004-01-01

    Patients at increased risk of colon cancer require strict colon surveillance. Our objective was to establish the efficacy of 2D axial CT colonography as a surveillance test when performed in routine clinical practice. Eighty-two patients at increased risk of colon cancer underwent CT colonography followed by conventional colonoscopy on the same morning. CT colonography studies were performed on a four-ring multidetector CT scanner (100 mAs, 120 kVp, 4 x 2.5 collimation) and were interpreted by two radiologists using 2D axial images only. Results were correlated with findings at colonoscopy. Note was made of subsequent histology reports from polypectomy specimens. A total of 52 polyps were detected at colonoscopy. Using 2D axial images alone, with no recourse to 2D multiplanar or 3D views, the sensitivity of CT colonography was 100, 33 and 19% for polyps larger than 9, 6-9 and smaller than 6 mm, respectively. Per-patient specificities were 98.8, 96 and 81.5%, respectively. Twenty-nine percent of polyps smaller than 1 cm were adenomatous and there were no histological features of severe dysplasia. CT colonography is a useful colon surveillance tool for patients at increased risk of colon cancer. It has a high specificity for identifying patients who should proceed to colonoscopy and polypectomy, while allowing further colon examination to be deferred in patients with normal studies. Using 2D axial images only, CT colonography can be performed as part of the daily CT workload, with a very low rate of referral for unnecessary colonoscopy. (orig.)

  5. Numerical analysis of a microwave torch with axial gas injection

    Energy Technology Data Exchange (ETDEWEB)

    Gritsinin, S. I.; Davydov, A. M.; Kossyi, I. A., E-mail: kossyi@fpl.gpi.ru [Russian Academy of Sciences, Prokhorov General Physics Institute (Russian Federation); Kulumbaev, E. B. [National Research University Belgorod State University (Russian Federation); Lelevkin, V. M. [Kyrgyz-Russian Slavic University (Kyrgyzstan)

    2013-07-15

    The characteristics of a microwave discharge in an argon jet injected axially into a coaxial channel with a shortened inner electrode are numerically analyzed using a self-consistent equilibrium gas-dynamic model. The specific features of the excitation and maintenance of the microwave discharge are determined, and the dependences of the discharge characteristics on the supplied electromagnetic power and gas flow rate are obtained. The calculated results are compared with experimental data.

  6. One-loop corrections to the baryon axial vector current

    Indian Academy of Sciences (India)

    2012-10-06

    Oct 6, 2012 ... 917–920. One-loop corrections to the baryon axial vector current. M A HERNÁNDEZ-RUÍZ1,2. 1Instituto de Física, Universidad Autónoma de San Luis Potosí,. Av. Manuel Nava 6 Zona Universitaria 78290, San Luis Potosí SLP, México. 2Facultad de Ciencias Químicas, Universidad Autónoma de Zacatecas,.

  7. Taming axial dispersion in hydrodynamic chromatography columns through wall patterning

    Science.gov (United States)

    Adrover, Alessandra; Cerbelli, Stefano; Giona, Massimiliano

    2018-04-01

    A well-known limitation of hydrodynamic chromatography arises from the synergistic interaction between transverse diffusion and streamwise convection, which enhances axial dispersion through the Taylor-Aris mechanism. We show that a periodic sequence of slip/no-slip conditions at the channel walls (e.g., representing wall indentations hosting stable air pockets) can significantly reduce axial dispersion, thus enhancing separation performance. The theoretical/numerical analysis is based on a generalization of Brenner's macrotransport approach to solute transport, here modified to account for the finite-size of the suspended particles. The most effective dispersion-taming outcome is observed when the alternating sequence of slip/no-slip conditions yields non-vanishing cross-sectional flow components. The combination of these components with the hindering interaction between the channel boundaries and the finite-sized particles gives rise to a non-trivial solution of Brenner's problem on the unit periodic cell, where the cross-sectional particle number density departs from the spatially homogeneous condition. In turn, this effect impacts upon the solution of the so-called b-field defining the large-scale dispersion tensor, with an overall decremental effect on the axial dispersion coefficient and on the Height Equivalent of a Theoretical Plate.

  8. Fundamental metallurgical aspects of axial splitting in zircaloy cladding

    International Nuclear Information System (INIS)

    Chung, H. M.

    2000-01-01

    Fundamental metallurgical aspects of axial splitting in irradiated Zircaloy cladding have been investigated by microstructural characterization and analytical modeling, with emphasis on application of the results to understand high-burnup fuel failure under RIA situations. Optical microscopy, SEM, and TEM were conducted on BWR and PWR fuel cladding tubes that were irradiated to fluence levels of 3.3 x 10 21 n cm -2 to 5.9 x 10 21 n cm -2 (E > 1 MeV) and tested in hot cell at 292--325 C in Ar. The morphology, distribution, and habit planes of macroscopic and microscopic hydrides in as-irradiated and posttest cladding were determined by stereo-TEM. The type and magnitude of the residual stress produced in association with oxide-layer growth and dense hydride precipitation, and several synergistic factors that strongly influence axial-splitting behavior were analyzed. The results of the microstructural characterization and stress analyses were then correlated with axial-splitting behavior of high-burnup PWR cladding reported for simulated-RIA conditions. The effects of key test procedures and their implications for the interpretation of RIA test results are discussed

  9. Imaging results and TOF studies with axial PET detectors

    CERN Document Server

    Joram, Christian

    2013-01-01

    We have developed a fully operational PET demonstrator setup which allows true 3D reconstruction of the 511 keV photons and therefore leads to practically parallax free images. The AX-PET concept is based on thin 100 mm long scintillation crystals (LYSO), axially oriented and arranged in layers around the held of view. Layers of wavelength shifting plastic strips mounted in between the crystal layers give the axial coordinate. Both crystals and WLS strips are individually read out by G-APD (SiPM) photodetectors. The Fully scalable concept overcomes the dilemma of sensitivity versus spatial resolution which is inherent to classical PET designs. A demonstrator set-up based on two axial modules was exhaustively characterized using point-like sources, phantoms filled with radiotracer and finally rats and a mouse. The results entirely meet the performance expectations ( <2 mm FWHM in all three coordinates over the complete held of view) and also demonstrated the ability to include Compton interactions (inter-cr...

  10. Imaging results and TOF studies with axial PET detectors

    Science.gov (United States)

    Joram, Christian

    2013-12-01

    We have developed a fully operational PET demonstrator setup which allows true 3D reconstruction of the 511 keV photons and therefore leads to practically parallax free images. The AX-PET concept is based on thin 100 mm long scintillation crystals (LYSO), axially oriented and arranged in layers around the field of view. Layers of wavelength shifting plastic strips mounted in between the crystal layers give the axial coordinate. Both crystals and WLS strips are individually read out by G-APD (SiPM) photodetectors. The fully scalable concept overcomes the dilemma of sensitivity versus spatial resolution which is inherent to classical PET designs. A demonstrator set-up based on two axial modules was exhaustively characterized using point-like sources, phantoms filled with radiotracer and finally rats and a mouse. The results entirely meet the performance expectations (PET concept making use of the novel digital SiPM detectors by Philips. After reproducing comparable energy and spatial resolution on a small digital AX-PET set-up with 100 mm long crystals, we demonstrated a coincidence resolving time of about 210 ps FWHM.

  11. The New Performance Calculation Method of Fouled Axial Flow Compressor

    Directory of Open Access Journals (Sweden)

    Huadong Yang

    2014-01-01

    Full Text Available Fouling is the most important performance degradation factor, so it is necessary to accurately predict the effect of fouling on engine performance. In the previous research, it is very difficult to accurately model the fouled axial flow compressor. This paper develops a new performance calculation method of fouled multistage axial flow compressor based on experiment result and operating data. For multistage compressor, the whole compressor is decomposed into two sections. The first section includes the first 50% stages which reflect the fouling level, and the second section includes the last 50% stages which are viewed as the clean stage because of less deposits. In this model, the performance of the first section is obtained by combining scaling law method and linear progression model with traditional stage stacking method; simultaneously ambient conditions and engine configurations are considered. On the other hand, the performance of the second section is calculated by averaged infinitesimal stage method which is based on Reynolds’ law of similarity. Finally, the model is successfully applied to predict the 8-stage axial flow compressor and 16-stage LM2500-30 compressor. The change of thermodynamic parameters such as pressure ratio, efficiency with the operating time, and stage number is analyzed in detail.

  12. Multi technical analysis of wear mechanisms in axial piston pumps

    Science.gov (United States)

    Schuhler, G.; Jourani, A.; Bouvier, S.; Perrochat, J.-M.

    2017-05-01

    Axial piston pumps convert a motor rotation motion into hydraulic or pneumatic power. Their compactness and efficiency of approximately 0.9 make them suitable for actuation applications especially in aeronautics. However, they suffer a limited life due to the wear of their components. In the literature, studies of axial piston pumps deal with contact between its different elements under lubrication conditions. Nevertheless, they are more focused on analytic or numerical approaches. This study consists in an experimental analysis of worn pump components to highlight and understand wear mechanisms. Piston shoes are central components in the axial piston pump since they are involved in three tribological contacts. These three contacts are thereby studied: piston shoes/swashplate, piston shoes/pistons and piston shoes/shoes hold down plate (SHDP). To perform this analysis, helicopter hydraulic pumps after different operating times have been studied. The wear damage mechanisms and wear debris are analysed using SEM observations. 3D surface roughness measurements are then used to characterize worn surfaces. The observations reveal that in the contact between shoes and swashplate, the main wear mechanism is three-body abrasive wear due to coarse carbides removal. Between shoes and pistons, wear occurs in a less severe way and is mainly due to the debris generated in the first contact and conveyed by the lubricating fluid. In the third contact, the debris are also the prime cause of the abrasive wear and the generation of deep craters in the piston shoes.

  13. Simultaneous Rotational and Axial Flow of Nonlinear Fluids

    Science.gov (United States)

    Ashrafi, Nariman; Yektapour, Mehdi; Shafahi, Mehdi

    2017-11-01

    An axial flow is introduced to the rotational flow of pseudoplastic fluids in the gap between concentric cylinders. The outer cylinder is fixed while the inner one has simultaneous and independent rotational and translational motions. The fluid follows the Carreau-Bird model and mixed boundary conditions are imposed. The four-dimensional low-order equations resulted from Galerkin projection of the conservation of mass and momentum equations, includes highly non-linear terms in the velocity components. Without axial flow, stability of the base radial flow is lost to the vortex structure at a lower critical Taylor number, with increase of the fluid pseudoplasticity. The vortices imply onset of a supercritical bifurcation which occurs in the rotational flow of linear fluids as well. In contrast to the Newtonian case, pseudoplastic Taylor vortices lose their stability at a second critical Taylor number is reached a second critical number that corresponds to the onset of a Hopf bifurcation. The axial flow, caused by the translational motion of the inner cylinder advance each critical point on the bifurcation diagram. The flow field and viscosity maps are provided for major stability regions.

  14. Behavior of unbonded flexible risers subject to axial tension

    Science.gov (United States)

    Ren, Shao-fei; Tang, Wen-yong; Guo, Jin-ting

    2014-04-01

    Owing to nonlinear contact problems with slip and friction, a lot of limiting assumptions are made when developing analytical models to simulate the behavior of an unbonded flexible riser. Meanwhile, in order to avoid convergence problems and excessive calculating time associated with running the detailed finite element (FE) model of an unbonded flexible riser, interlocked carcass and zeta layers with complicated cross section shapes are replaced by simple geometrical shapes (e.g. hollow cylindrical shell) with equivalent orthotropic materials. But the simplified model does not imply the stresses equivalence of these two layers. To solve these problems, based on ABAQUS/Explicit, a numerical method that is suitable for the detailed FE model is proposed. In consideration of interaction among all component layers, the axial stiffness of an eight-layer unbonded flexible riser subjected to axial tension is predicted. Compared with analytical and experimental results, it is shown that the proposed numerical method not only has high accuracy but also can substantially reduce the calculating time. In addition, the impact of the lay angle of helical tendons on axial stiffness is discussed.

  15. HTS axial flux induction motor with analytic and FEA modeling

    International Nuclear Information System (INIS)

    Li, S.; Fan, Y.; Fang, J.; Qin, W.; Lv, G.; Li, J.H.

    2013-01-01

    Highlights: •A high temperature superconductor axial flux induction motor and a novel maglev scheme are presented. •Analytic method and finite element method have been adopted to model the motor and to calculate the force. •Magnetic field distribution in HTS coil is calculated by analytic method. •An effective method to improve the critical current of HTS coil is presented. •AC losses of HTS coils in the HTS axial flux induction motor are estimated and tested. -- Abstract: This paper presents a high-temperature superconductor (HTS) axial-flux induction motor, which can output levitation force and torque simultaneously. In order to analyze the character of the force, analytic method and finite element method are adopted to model the motor. To make sure the HTS can carry sufficiently large current and work well, the magnetic field distribution in HTS coil is calculated. An effective method to improve the critical current of HTS coil is presented. Then, AC losses in HTS windings in the motor are estimated and tested

  16. Axial power monitoring uncertainty in the Savannah River Reactors

    International Nuclear Information System (INIS)

    Losey, D.C.; Revolinski, S.M.

    1990-01-01

    The results of this analysis quantified the uncertainty associated with monitoring the Axial Power Shape (APS) in the Savannah River Reactors. Thermocouples at each assembly flow exit map the radial power distribution and are the primary means of monitoring power in these reactors. The remaining uncertainty in power monitoring is associated with the relative axial power distribution. The APS is monitored by seven sensors that respond to power on each of nine vertical Axial Power Monitor (APM) rods. Computation of the APS uncertainty, for the reactor power limits analysis, started with a large database of APM rod measurements spanning several years of reactor operation. A computer algorithm was used to randomly select a sample of APSs which were input to a code. This code modeled the thermal-hydraulic performance of a single fuel assembly during a design basis Loss-of Coolant Accident. The assembly power limit at Onset of Significant Voiding was computed for each APS. The output was a distribution of expected assembly power limits that was adjusted to account for the biases caused by instrumentation error and by measuring 7 points rather than a continuous APS. Statistical analysis of the final assembly power limit distribution showed that reducing reactor power by approximately 3% was sufficient to account for APS variation. This data confirmed expectations that the assembly exit thermocouples provide all information needed for monitoring core power. The computational analysis results also quantified the contribution to power limits of the various uncertainties such as instrumentation error

  17. Numerical Analysis of Erosion Caused by Biomimetic Axial Fan Blade

    Directory of Open Access Journals (Sweden)

    Jun-Qiu Zhang

    2013-01-01

    Full Text Available Damage caused by erosion has been reported in several industries for a wide range of situations. In the present work, a new method is presented to improve the erosion resistance of machine components by biomimetic method. A numerical investigation of solid particle erosion in the standard and biomimetic configuration blade of axial fan is presented. The analysis consists in the application of the discrete phase model, for modeling the solid particles flow, and the Eulerian conservation equations to the continuous phase. The numerical study employs computational fluid dynamics (CFD software, based on a finite volume method. User-defined function was used to define wear equation. Gas/solid flow axial fan was simulated to calculate the erosion rate of the particles on the fan blades and comparatively analyzed the erosive wear of the smooth surface, the groove-shaped, and convex hull-shaped biomimetic surface axial flow fan blade. The results show that the groove-shaped biomimetic blade antierosion ability is better than that of the other two fan blades. Thoroughly analyze of antierosion mechanism of the biomimetic blade from many factors including the flow velocity contours and flow path lines, impact velocity, impact angle, particle trajectories, and the number of collisions.

  18. Characteristics of tip-leakage flow in an axial fan

    Science.gov (United States)

    Park, Keuntae; Choi, Haecheon; Choi, Seokho; Sa, Yongcheol

    2014-11-01

    An axial fan with a shroud generates complicated vortical structures by the interaction of the axial flow with the fan blades and shroud near the blade tips. Large eddy simulation (LES) is performed for flow through a forward-swept axial fan, operating at the design condition of Re = 547,000 based on the radius of blade tip and the tip velocity. A dynamic global model (Lee et al. 2010) is used for a subgrid-scale model, and an immersed boundary method in a non-inertial reference frame (Kim & Choi 2006) is adopted for the present simulation. It is found that two vortical structures are formed near the blade tip: the main tip leakage vortex (TLV) and the auxiliary TLV. The main TLV is initiated near the leading edge, develops downstream, and impinges on the pressure surface of the next blade, where the pressure fluctuations and turbulence intensity become high. On the other hand, the auxiliary TLV is initiated at the aft part of the blade but is relatively weak such that it merges with the main TLV. Supported by the KISTI Supercomputing Center (KSC-2014-C2-014).

  19. Valor da ultra-sonografia e da tomografia computadorizada no tratamento cirúrgico das neoplasias da glândula parótida

    Directory of Open Access Journals (Sweden)

    Margarida Maria dos Santos Antunes

    Full Text Available OBJETIVO: Avaliar o valor da ultra-sonografia (US e tomografia computadorizada (TC no planejamento cirúrgico das neoplasias da glândula parótida. MÉTODO: Estudo retrospectivo de 56 pacientes portadores de neoplasias da glândula parótida (43 benignas e 13 malignas, tratados nos Departamentos de Cirurgia de Cabeça e Pescoço/Otorrinolaringologia e Diagnóstico por Imagem do Hospital Heliópolis, Hosphel, São Paulo (1991 a 1999. Comparamos os achados por US (45 e TC (15 com os histopatológicos pós-cirúrgicos empregando-se o teste diagnóstico de sensibilidade e especificidade. RESULTADOS: Dos 45 exames de US, a consistência sólida foi diagnosticada em 33 casos (sensibilidade de 89% e especificidade de 50% e a cística em quatro casos (sensibilidade e especificidade de 50%. Quanto à localização no lobo superficial, houve coincidência em 31 casos (sensibilidade de 91,2% e especificidade em 36,5%, e para o lobo profundo em quatro casos (sensibilidade de 40% e especificidade de 88,6%. Quanto aos 15 exames de TC, a consistência sólida foi demonstrada em 13 casos (sensibilidade de 86,7% e especificidade de 0% e a cística em nenhum caso (sensibilidade de 0% e especificidade de 86,7%. Quanto à localização no lobo superficial, houve coincidência em um caso (sensibilidade de 20% e especificidade em 90%, e para o lobo profundo em nove casos (sensibilidade de 90% e especificidade de 20%. CONCLUSÕES: 1. A US foi o método de escolha para lesões sólidas no lobo superficial e falha no lobo profundo. 2. A TC foi o método de escolha para as lesões do lobo profundo, e falhou nas lesões císticas no lobo superficial.

  20. Prognóstico visual de 'crosslinking' para ceratocone com base em tomografia de córnea pré-operatória

    Directory of Open Access Journals (Sweden)

    Lopes Bernardo

    2014-08-01

    Full Text Available Objetivo: Verificar índices tomográficos do pré-operatório de pacientes com ceratocone submetidos à crosslinking corneano (CXL como fatores preditivos para a melhora na acuidade visual corrigidas (AVc após um ano. Métodos: Estudo retrospectivo que incluiu 63 olhos de 53 pacientes com ceratocone progressivo submetidos à CXL segundo o protocolo de Dresden: deseptelização corneana, riboflavina 0,1% por 30 minutos e luz ultra-violeta A (UVA a uma irradiância de 3mW/cm2 por 30 minutos. Foram avaliados exames de tomografia corneana com sistema de Scheimpflug rotacional (Pentacam, Oculus antes do CXL e a acuidade visual corrigida antes e após a cirurgia. A análise estatística foi feita com o teste de Kolmorov-Smirnov, teste t de student e curvas de característica operador-receptor (ROC. Resultados: Houve diferença estatisticamente significante (p<0,05 entre os pacientes que obtiveram melhora de AVc em um ano e os que não experimentaram melhora na AVc nesse período nos índices tomográficos pré-operatórios relacionados com espessura e volume corneano. Entre os pacientes que obtiveram melhora na AVc todos possuíam volume corneano em 6,0mm maior que 14,55mm3 e 97,2% deles possuíam volume corneano em 6,5mm maior que 17,76mm3. Assim como, 94,29% desses pacientes apresentavam paquimetria média em 4,0mm maior que 487 μm e 82,86% paquimetria no ponto mais fino maior de 421 μm. Conclusão: Pacientes com ceratocone menos avançado (volume e espessura da córnea maiores no período pré-operatório obtiveram mais chances de ter melhora da AVc um ano após CXL. Estudos prospectivos envolvendo outras variáveis relacionadas com a aberrometria total e o estudo biomecânico da córnea são relevantes para se aumentar a capacidade prognóstica do resultado após CXL.

  1. Hemorragia intraparenquimatosa encefálica espontânea: achados à tomografia computadorizada Spontaneous intraparenchymatous hemorrhage: findings at computed tomography

    Directory of Open Access Journals (Sweden)

    Celso Monteiro Soares

    2004-09-01

    Full Text Available Foram analisados os exames de tomografia computadorizada de crânio de 250 pacientes com hematoma intraparenquimatoso encefálico espontâneo em três diferentes hospitais na cidade do Rio de Janeiro, com o objetivo de se levantar os aspectos mais freqüentes desta doença. O hematoma intraparenquimatoso cerebral profundo foi o de maior incidência, seguido do lobar. Mais raramente foi observado sangramento cerebelar e do tronco cerebral. A faixa etária de acometimento mais freqüente foi entre 61 e 70 anos de idade. Não houve diferença expressiva quanto ao sexo predominante ou ao lado mais acometido, porém verificou-se que os homens são mais acometidos em uma faixa etária mais precoce do que as mulheres. A cefaléia foi o sintoma de maior freqüência e a hipertensão arterial esteve presente na maioria dos casos. A drenagem da hemorragia para o sistema ventricular ocorreu mais comumente nos hematomas profundos.Computed tomography studies of 250 patients with spontaneous hemorrhage were examined in three hospitals in the city of Rio de Janeiro. The goal of this study was to identify the aspects of this disease that appear most frequently in this type of exam. Deep intracerebral hematomas have had the highest incidence followed by lobar hemorrhage, with thalamus being more frequently affected. Cerebelar hemorrhage was much rarer, with brainstem bleeding observed in few patients. The age group with a peak incidence was at 61 to 70 years. Headache was the most frequently related symptom and elevated levels of blood pressure were found in most of the cases. There was no pronounced difference as to predominance in either sex or side most affected but it was observed that the onset of this disease occurs at an earlier age in men than in women. Blood draining into the ventricular system occurred more frequently in deep hematomas.

  2. Axial resolution of confocal Raman microscopes : Gaussian beam theory and practice

    NARCIS (Netherlands)

    Grauw, C J De; Sijtsema, N M; Otto, C; Greve, J

    1997-01-01

    A straightforward and transparent model, based on Gaussian beam optics, for the axial ro resolution of a confocal microscope is presented, A confocal Raman microscope was used to determine the axial confocality in practice. The axial response of a thin planar object was measured for three different

  3. Axial Resolution of Confocal Raman Microscopes: Gaussian Beam Theory and Practice

    NARCIS (Netherlands)

    de Grauw, C.J.; de Grauw, C.J.; Sijtsema, N.M.; Otto, Cornelis; Greve, Jan

    1997-01-01

    A straightforward and transparent model, based on Gaussian beam optics, for the axial r0 resolution of a confocal microscope is presented. A confocal Raman microscope was used to determine the axial confocality in practice. The axial response of a thin planar object was measured for three different

  4. Reconstrução do seio maxilar atrófico com enxerto autólogo de crista ilíaca: avaliação por tomografia computadorizada e radiografia panorâmica

    Directory of Open Access Journals (Sweden)

    André Luíz Zétola

    Full Text Available OBJETIVOS: As dificuldades para a utilização de implantes dentários osteointegrados em pacientes portadores de atrofia do seio maxilar justificaram o emprego de enxerto autólogo não vascularizado de crista ilíaca isolado ou associado à hidroxiapatita (HA em 14 pacientes submetidos a 25 procedimentos no Hospital das Nações, Curitiba, Paraná, portadores de atrofia do sinus maxilar. O objetivo foi avaliar comparativamente a precisão da tomografia computadorizada e da radiografia panorâmica, através da quantificação da neoformação óssea nesta estrutura. MÉTODOS: Foram selecionadas pacientes edentados, com altura óssea residual do rebordo gengival ao soalho do seio maxilar menor que 5mm. O enxerto medular de crista ilíaca fragmentada isolado ou misturado com HA foi colocado através da parede lateral no soalho atrófico da cuba maxilar por via submucosa. A avaliação quantitativa e qualitativa foi feita através da radiografia panorâmica e tomografia computadorizada, sendo utilizado na análise estatística a distribuição t de Student (prevalência de 0,05 para análise das variâncias, considerado que a leitura dos laudos radiológicos foi feita por dois especialistas, medindo a distância entre os pontos inferiores e superiores do enxerto no soalho do seio maxilar. RESULTADOS: Tivemos um ganho médio de 14,8mm em todos os procedimentos, com um erro maior que 3mm em 16 procedimentos (64% e incorporação satisfatória do enxerto ósseo suficiente para futuro implante dentário. CONCLUSÕES: A tomografia computadorizada foi o método de escolha na avaliação qualitativa e quantitativa da incorporação de enxerto autólogo não vascularizado em seio maxilar atrófico.

  5. A tomografia computadorizada de alta resolução na avaliação da toxicidade pulmonar por amiodarona High-resolution computed tomography of amiodarone pulmonary toxicity

    Directory of Open Access Journals (Sweden)

    Daniela Peixoto Consídera

    2006-04-01

    Full Text Available OBJETIVO: Avaliar as principais alterações identificadas na tomografia computadorizada de alta resolução do tórax em pacientes com toxicidade pulmonar pela amiodarona. MATERIAIS E MÉTODOS: Foram avaliadas dez tomografias computadorizadas de alta resolução de tórax de pacientes com pneumonite pela amiodarona, seis desses pacientes do sexo masculino e quatro do sexo feminino, com idade média de 73,5 anos. RESULTADOS: Os achados tomográficos mais relevantes foram opacidades lineares ou reticulares em seis casos (60%, pequenos nódulos com densidade elevada em seis casos (60%, consolidações densas em três casos (30% e aumento da densidade do parênquima hepático em cinco de oito casos em que havia estudo tomográfico do abdome superior (62,5%. CONCLUSÃO: A tomografia computadorizada de alta resolução é um exame importante na avaliação de pacientes com toxicidade pulmonar pela amiodarona, devendo ser realizada sempre que houver suspeita deste diagnóstico. O achado de espessamento de septos interlobulares associado a lesões com aumento de densidade é altamente sugestivo deste diagnóstico.OBJECTIVE: To evaluate the main findings of chest high-resolution computed tomography in patients with amiodarone pulmonary toxicity. MATERIALS AND METHODS: Ten patients - six male and four female, average age of 73.5 years - with amiodarone-induced pneumonitis have undergone chest high-resolution computed tomography. RESULTS: The most relevant tomographic findings were linear or reticular opacities in six cases (60%, small high density nodules in six cases (60%, dense consolidations in three cases (30% and increased density in the hepatic parenchyma in five of eight cases in which there was a superior abdomen CT scan (62.5%. CONCLUSION: The high-resolution computed tomography is a valuable non-invasive test for evaluating patients with amiodarone pulmonary toxicity and should always be performed when one suspects of the presence of this

  6. Experimental Study of Axially Tension Cold Formed Steel Channel Members

    Science.gov (United States)

    Apriani, Widya; Lubis, Fadrizal; Angraini, Muthia

    2017-12-01

    Experimental testing is commonly used as one of the steps to determine the cause of the collapse of a building structure. The collapse of structures can be due to low quality materials. Although material samples have passed laboratory tests and the existing technical specifications have been met but there may be undetected defects and known material after failure. In this paper will be presented Experimental Testing of Axially Tension Cold Formed Steel Channel Members to determine the cause of the collapse of a building roof truss x in Pekanbaru. Test of tensile strength material cold formed channel sections was performed to obtain the main characteristics of Cold Formed steel material, namely ultimate tensile strength loads that can be held by members and the yield stress possessed by channel sections used in construction. Analysis of axially tension cold formed steel channel section presents in this paper was conducted through experimental study based on specificationsAnnualBook of ASTM Standards: Metal Test methods and Analitical Procedures, Section 3 (1991). The result of capacity loads experimental test was compared with design based on SNI 03-7971-2013standard of Indonesia for the design of cold formed steel structural members. The results of the yield stress of the material will be seen against the minimum allowable allowable stress range. After the test, the percentace of ultimate axial tension capacity theory has a result that is 16.46% larger than the ultimate axial tension capacity experimental. When compared with the load that must be borne 5.673 kN/m it can be concluded that 2 specimens do not meet. Yield stress of member has fulfilled requirement that wass bigger than 550 MPa. Based on the curve obtained ultimate axial tension capacity theory, results greater than experimental. The greatest voltage value (fu) is achieved under the same conditions as its yield stress. For this specimen with a melting voltage value fy = 571.5068 MPa has fulfilled the

  7. Design and axial optimization of nuclear fuel for BWR reactors

    International Nuclear Information System (INIS)

    Garcia V, M.A.

    2006-01-01

    In the present thesis, the modifications made to the axial optimization system based on Tabu Search (BT) for the axial design of BWR fuel type are presented, developed previously in the Nuclear Engineering Group of the UNAM Engineering Faculty. With the modifications what is mainly looked is to consider the particular characteristics of the mechanical design of the GE12 fuel type, used at the moment in the Laguna Verde Nucleo electric Central (CNLV) and that it considers the fuel bars of partial longitude. The information obtained in this thesis will allow to plan nuclear fuel reloads with the best conditions to operate in a certain cycle guaranteeing a better yield and use in the fuel burnt, additionally people in charge in the reload planning will be favored with the changes carried out to the system for the design and axial optimization of nuclear fuel, which facilitate their handling and it reduces their execution time. This thesis this developed in five chapters that are understood in the following way in general: Chapter 1: It approaches the basic concepts of the nuclear energy, it describes the physical and chemical composition of the atoms as well as that of the uranium isotopes, the handling of the uranium isotope by means of the nuclear fission until arriving to the operation of the nuclear reactors. Chapter 2: The nuclear fuel cycle is described, the methods for its extraction, its conversion and its enrichment to arrive to the stages of the nuclear fuel management used in the reactors are described. Beginning by the radial design, the axial design and the core design of the nuclear reactor related with the fuel assemblies design. Chapter 3: the optimization methods of nuclear fuel previously used are exposed among those that are: the genetic algorithms method, the search methods based on heuristic rules and the application of the tabu search method, which was used for the development of this thesis. Chapter 4: In this part the used methodology to the

  8. Experimental Studies on Strength Behaviour of Notched Glass/Epoxy Laminated Composites under Uni-axial and Bi-axial Loading

    Science.gov (United States)

    Guptha, V. L. Jagannatha; Sharma, Ramesh S.

    2017-11-01

    The use of FRP composite materials in aerospace, aviation, marine, automotive and civil engineering industry has increased rapidly in recent years due to their high specific strength and stiffness properties. The structural members contrived from such composite materials are generally subjected to complex loading conditions and leads to multi-axial stress conditions at critical surface localities. Presence of notches, much required for joining process of composites, makes it further significant. The current practice of using uni-axial test data alone to validate proposed material models is inadequate leading to evaluation and consideration of bi-axial test data. In order to correlate the bi-axial strengths with the uni-axial strengths of GFRP composite laminates in the presence of a circular notch, bi-axial tests using four servo-hydraulic actuators with four load cells were carried out. To determine the in-plane strength parameters, bi-axial cruciform test specimen model was considered. Three different fibre orientations, namely, 0°, 45°, and 90° are considered with a central circular notch of 10 mm diameter in the present investigation. From the results obtained, it is observed that there is a reduction in strength of 5.36, 2.41 and 13.92% in 0°, 45°, and 90° fibre orientation, respectively, under bi-axial loading condition as compared to that of uni-axial loading in laminated composite.

  9. Definição do nível da junção ureterovesical pela tomografia computadorizada Definition of ureterovesical junction level by computed tomography

    Directory of Open Access Journals (Sweden)

    Edison de Oliveira Freire Filho

    2006-12-01

    Full Text Available OBJETIVO: Definir o nível da implantação ureteral na bexiga através da tomografia computadorizada. MATERIAIS E MÉTODOS: Através de tomografia computadorizada da pelve com contraste endovenoso de 46 pacientes (31 homens e 15 mulheres com idade entre 18 e 45 anos, com pelo menos um dos ureteres contrastado pelo contraste excretado, medimos as distâncias do meato ureteral até o teto acetabular e a borda superior da sínfise púbica, além do volume da bexiga. Utilizamos o teste t de Student para avaliar se houve diferenças estatísticas entre grupos. RESULTADOS: O nível da implantação ureteral na bexiga foi, em média, 10,6 ± 8,1 mm abaixo do teto acetabular e, em média, 29,7 ± 9,5 mm acima da borda superior da sínfise púbica. Nos pacientes com volume de repleção vesical menor que 200 ml e maior ou igual a 200 ml os níveis da implantação ureteral na bexiga foram, em média, 11,6 ± 7,3 mm e 10,2 ± 8,4 mm abaixo do teto acetabular (p = 0,61 e, em média, 28,3 ± 7,3 mm e 30,3 ± 10,2 mm acima da borda superior da sínfise púbica (p = 0,52, respectivamente, e nos pacientes do sexo masculino e feminino foram, em média, 11,8 ± 8,0 mm e 8,3 ± 8,0 mm abaixo do teto acetabular (p = 0,17 e, em média, 27,7 ± 9,2 mm e 33,9 ± 8,8 mm acima da borda superior da sínfise púbica (p = 0,34, respectivamente. CONCLUSÃO: Calcificações localizadas abaixo de 3 cm do teto acetabular e abaixo de 1,5 cm acima da borda superior da sínfise púbica provavelmente não representam cálculos ureterais. O grau de repleção vesical e o sexo não interferem significativamente na posição do meato ureteral.OBJECTIVE: To define, by means of computed tomography, the level of ureteral implantation into de bladder. MATERIALS AND METHODS: We have measured the distances from the ureteral meatus to the acetabulum, and to the superior margin of the pubic symphysis, as well as the bladder volume, using contrast enhanced computed tomography of the pelvis

  10. Design and axial optimization of nuclear fuel for BWR reactors; Diseno y optimizacion axial de combustible nuclear para reactores BWR

    Energy Technology Data Exchange (ETDEWEB)

    Garcia V, M.A

    2006-07-01

    In the present thesis, the modifications made to the axial optimization system based on Tabu Search (BT) for the axial design of BWR fuel type are presented, developed previously in the Nuclear Engineering Group of the UNAM Engineering Faculty. With the modifications what is mainly looked is to consider the particular characteristics of the mechanical design of the GE12 fuel type, used at the moment in the Laguna Verde Nucleo electric Central (CNLV) and that it considers the fuel bars of partial longitude. The information obtained in this thesis will allow to plan nuclear fuel reloads with the best conditions to operate in a certain cycle guaranteeing a better yield and use in the fuel burnt, additionally people in charge in the reload planning will be favored with the changes carried out to the system for the design and axial optimization of nuclear fuel, which facilitate their handling and it reduces their execution time. This thesis this developed in five chapters that are understood in the following way in general: Chapter 1: It approaches the basic concepts of the nuclear energy, it describes the physical and chemical composition of the atoms as well as that of the uranium isotopes, the handling of the uranium isotope by means of the nuclear fission until arriving to the operation of the nuclear reactors. Chapter 2: The nuclear fuel cycle is described, the methods for its extraction, its conversion and its enrichment to arrive to the stages of the nuclear fuel management used in the reactors are described. Beginning by the radial design, the axial design and the core design of the nuclear reactor related with the fuel assemblies design. Chapter 3: the optimization methods of nuclear fuel previously used are exposed among those that are: the genetic algorithms method, the search methods based on heuristic rules and the application of the tabu search method, which was used for the development of this thesis. Chapter 4: In this part the used methodology to the

  11. Paracoccidioidomycosis: high-resolution computed tomography - anatomo-pathological correlation; Paracoccidioidomicose: correlacao da tomografia computadorizada de alta resolucao com a anatomopatologia

    Energy Technology Data Exchange (ETDEWEB)

    Marchiori, Edson; Muniz, Maria Angelica Soares; Santos, Maria Lucia de Oliveira [Universidade Federal Fluminense, Niteroi, RJ (Brazil). Inst. de Radiologia; Moraes, Heleno Pinto de [Universidade Federal Fluminense, Niteroi, RJ (Brazil). Inst. de Patologia; Capone, Domenico [Universidade do Estado, Rio de Janeiro, RJ (Brazil). Inst. de Pneumologia

    2000-12-01

    We reviewed the high-resolution computed tomography scans of 13 patients with paracoccidioidomycosis and correlated the findings with the anatomo-pathological findings of 5 patients. The most frequent findings observed were thickening of the interlobular septa, emphysema, ground glass areas, thickening of bronchial walls, tracheal dilatation, nodules, cavities and evidence of fibrosing disease such as architectural distortion, parenchymatous bands, spicular pleural thickening, intralobular reticulate and thickening with distortion off the axial interstitium. (author)

  12. Evaluación de la disponibilidad, utilización y costos de la tomografía computarizada en el estado de Morelos, México Assessment of the availability, utilization, and costs of computerized tomography in Morelos, Mexico

    Directory of Open Access Journals (Sweden)

    John Pérez-Rodríguez

    2002-09-01

    Full Text Available Objetivo. Evaluar la disponibilidad, utilización y costos económicos de la tomografía computarizada (TC en hospitales públicos y privados en el estado de Morelos, México. Material y métodos. Mediante un estudio transversal efectuado entre enero y abril de 1999, se evaluaron cuatro hospitales en el estado de Morelos, dos públicos y dos privados. Se llevaron a cabo entrevistas individuales con los directores, administradores, médicos radiólogos y jefes de mantenimiento. Se realizó un análisis estadístico descriptivo de las variables, disponibilidad, utilización y costos, así como una evaluación integral de la tomografía, haciendo énfasis en la variabilidad de los patrones observados en los hospitales participantes en el estudio. Resultados. La TC es una tecnología utilizada en los hospitales del estado de Morelos desde hace más de 10 años. Aun cuando existen programas de mantenimiento preventivo y correctivo a los equipos de tomografía, sus costos son muy elevados. Además se carece de estrategias que permitan evaluar la tecnología antes de su adquisición y durante su utilización. El estudio no incluyó aspectos relativos a la correcta indicación clínica de la TC, ni a sus posibles efectos secundarios. Conclusiones. Los hallazgos obtenidos a partir de la presente investigación fueron los siguientes: a existe una carencia de procesos de evaluación y gestión tecnológica, que permita a las unidades hospitalarias un manejo eficiente de la tomografía computarizada, y b también se carece de mecanismos para regular la adquisición, evaluar la tecnología y seleccionar las mejores alternativas en función de su efectividad, eficacia, seguridad y accesibilidad.Objective. To assess the availability, utilization, and costs of computerized tomography (CT scan in private and public hospitals in Morelos State, Mexico. Material and Methods. From January to April 1999, a cross-sectional study was carried out in two private and two

  13. Uma rara causa de dispnéia com apresentação singular na tomografia computadorizada de tórax: síndrome de ativação macrofágica

    OpenAIRE

    Brandão-Neto,Rodrigo Antônio; Santana,Alfredo Nicodemos Cruz; Danilovic,Debora Lucia Seguro; Bernardi,Fabíola Del Carlo; Barbas,Carmen Silvia Valente; Mendonça,Berenice Bilharinho de

    2008-01-01

    A síndrome de ativação macrofágica é uma doença rara e potencialmente fatal. Ela ocorre devido a uma alteração no sistema imunológico, com excessiva proliferação de macrófagos, geralmente causando hepatoesplenomegalia, pancitopenia e disfunção hepática. Neste artigo, relatamos uma raríssima apresentação da síndrome de ativação macrofágica como insuficiência respiratória, bem como a primeira descrição de nódulo escavado, vidro fosco e consolidação na tomografia computadorizada de alta resoluçã...

  14. Camada de fibras nervosas da retina em portadores de esquistossomose mansônica na forma hepatoesplênica: análise por tomografia de coerência óptica

    Directory of Open Access Journals (Sweden)

    Ana Carolina Celino

    2015-04-01

    Full Text Available Objetivo: Avaliar a espessura da camada de fibras nervosas da retina em portadores de esquistossomose mansônica na forma hepatoesplênica utilizando a tomografia de coerência óptica. Métodos: Realizou-se estudo observacional, analítico, de corte transversal. O grupo de doentes foi composto por 24 indivíduos (13 femininos e 11 masculinos, com idades variando entre 27 e 73 anos (55,7±11,6 anos. No grupo controle foram incluídos 22 indivíduos (12 femininos e 10 masculinos com idades entre 31 e 77 anos (55,4±16,5 anos. Dos 92 olhos avaliados, três foram excluídos por apresentarem opacidade de meios que impossibilitaram o exame. Todos os participantes foram submetidos ao exame oftalmológico completo e medida da camada de fibras nervosas da retina pela tomografia de coerência óptica. Resultados: A média das espessuras da camada de fibras nervosas da retina foi de 98,1±15,2μm no grupo de estudo e 114,2±10,0 μm no grupo controle (p<0,001. Conclusão: Observou-se diminuição significante da espessura da camada de fibras nervosas da retina, em todos os quadrantes, nos pacientes com esquistossomose mansônica na forma hepatoesplênica.

  15. Pneumonia pelo vírus influenza B pós-transplante de medula óssea: relato de caso com ênfase dos achados de tomografia computadorizada de alta resolução

    Directory of Open Access Journals (Sweden)

    Emerson L. Gasparetto

    2005-01-01

    Full Text Available Resumo: Doente do sexo masculino, 9 anos, transplantado de medula óssea devido leucemia mielóide aguda, apresentou febre e tosse seca três dias após o procedimento. A radiografia de tórax demonstrou infiltrado reticular difuso bilateral. A tomografia computadorizada de alta resolução do tórax revelou espessamento do interstício peribroncovascular, pequenos nódulos centrolobulares periféricos e áreas de atenuação em vidro fosco. O lavado broncoalveolar demonstrou pesquisa positiva por imunofluorescência direta para anticorpos anti-vírus influenza B. Foi instituído tratamento com ribavirina aerolizada durante 10 dias com melhoria clínico-radiológica do quadro infeccioso.Rev Port Pneumol 2005; XI (1: 63-66 Abstract: Nine year-old male patient, who underwent bone marrow transplantation because of acute myelogenous leukemia, presented with fever and dry cough three days after the procedure. The chest radiograph demonstrated bilateral diffuse reticular infiltrate. The high resolution computed tomography showed peribronchovascular interstitial thickening, peripheral small centrilobular nodules and areas of ground-glass attenuation. The bronchoalveolar lavage demonstrated positive direct fluorescence antibody testing against influenza B virus. Treatment with aerolizated ribavirin was instituted during 10 days and the patient showed clinical-radiological improvement.Rev Port Pneumol 2005; XI (1: 63-66 Palavras-chave: Vírus influenza B, tomografia computadorizada de alta resolução, transplante de medula óssea, Key-words: Influenza B virus, high resolution computed tomography, bone marrow transplantation

  16. Tomografia emissora de positrões: Indicações no cancro do pulmão – Experiência prospectiva de um serviço

    Directory of Open Access Journals (Sweden)

    Diva Ferreira

    2007-01-01

    Full Text Available Resumo: A tomografia emissora de positrões (PET é uma tecnologia recente no âmbito da medicina nuclear. Utiliza radionuclídeos biológicos como o 18 F-fluoro-2-deo-xy-D-glicose (FDG permitindo detectar locais onde o metabolismo está aumentado, como no caso de células neoplásicas. Tem vindo a tornar-se um inovador e importante meio imagiológico no cancro do pulmão. Recomendações actuais incluem o diagnóstico de cancro do pulmão, bem como o estadiamento loco-regional e à distancia do CPNPC.Rev Port Pneumol 2007; XIII (1: 35-51 Abstract: Positron emission tomography (PET is a new technique in nuclear medicine. It uses biological radiotracers such as 18 F-fluoro-2-deoxyglucose (FDG which permit the detection of suspected lesions with metabolic alterations that take up the glucose isotope too avidly, as is the case with neoplastic cells. PET has become an innovatory and important imaging tool for evaluating patients with lung cancer. The present recommended uses of PET include lung cancer diagnosis and the intrathoracic and extrathoracic staging in N-SCLC.Rev Port Pneumol 2007; XIII (1: 35-51 Palavras-chave: Tomografia emissora de positrões, cancro do pulmão, diagnóstico, estadiamento, Key-words: Positron emission tomography, lung cancer, diagnosis, staging

  17. Renormalization of the axial-vector current in QCD

    International Nuclear Information System (INIS)

    Chiu, C.B.; Pasupathy, J.; Wilson, S.L.

    1985-01-01

    Following the method of Ioffe and Smilga, the propagation of the baryon current in an external constant axial-vector field is considered. The close similarity of the operator-product expansion with and without an external field is shown to arise from the chiral invariance of gauge interactions in perturbation theory. Several sum rules corresponding to various invariants both for the nucleon and the hyperons are derived. The analysis of the sum rules is carried out by two independent methods, one called the ratio method and the other called the continuum method, paying special attention to the nondiagonal transitions induced by the external field between the ground state and excited states. Up to operators of dimension six, two new external-field-induced vacuum expectation values enter the calculations. Previous work determining these expectation values from PCAC (partial conservation of axial-vector current) are utilized. Our determination from the sum rules of the nucleon axial-vector renormalization constant G/sub A/, as well as the Cabibbo coupling constants in the SU 3 -symmetric limit (m/sub s/ = 0), is in reasonable accord with the experimental values. Uncertainties in the analysis are pointed out. The case of broken flavor SU 3 symmetry is also considered. While in the ratio method, the results are stable for variation of the fiducial interval of the Borel mass parameter over which the left-hand side and the right-hand side of the sum rules are matched, in the continuum method the results are less stable. Another set of sum rules determines the value of the linear combination 7F-5D to be roughly-equal0, or D/(F+D)roughly-equal(7/12). .AE

  18. Axial dispersion via shear-enhanced diffusion in colloidal suspensions

    KAUST Repository

    Griffiths, I. M.

    2012-03-01

    The familiar example of Taylor dispersion of molecular solutes is extended to describe colloidal suspensions, where the fluctuations that contribute to dispersion arise from hydrodynamic interactions. The generic scheme is illustrated for a suspension of particles in a pressure-driven pipe flow, with a concentration-dependent diffusivity that captures both the shear-induced and Brownian contributions. The effect of the cross-stream migration via shear-induced diffusion is shown to dramatically reduce the axial dispersion predicted by classical Taylor dispersion for a molecular solute. Analytic and numerical solutions are presented that illustrate the effect of the concentration dependence of this nonlinear hydrodynamic mechanism. Copyright © EPLA, 2012.

  19. Axial gas flow in irradiated PWR fuel rods

    International Nuclear Information System (INIS)

    Dagbjartsson, S.J.; Murdock, B.A.; Owen, D.E.; MacDonald, P.E.

    1977-09-01

    Transient and steady state axial gas flow experiments were performed on six irradiated, commercial pressurized water reactor fuel rods at ambient temperature and 533 K. Laminar flow equations, as used in the FRAP-T2 and SSYST fuel behavior codes, were used with the gas flow results to calculate effective fuel rod radial gaps. The results of these analyses were compared with measured gap sizes obtained from metallographic examination of one fuel rod. Using measured gap sizes as input, the SSYST code was used to calculate pressure drops and mass fluxes and the results were compared with the experimental gas flow data

  20. Test Procedure for Axially Loaded Piles in Sand

    DEFF Research Database (Denmark)

    Thomassen, Kristina

    The test procedure described in the following is used when examining the effects of static or cyclic loading on the skin friction of an axially loaded pile in dense sand. The pile specimen is only loaded in tension to avoid any contribution from the base resistance. The pile dimensions are chosen...... to resemble full scale dimension of piles used in offshore pile foundations today. In this report is given a detailed description of the soil preparation and pile installation procedures as well data acquisition methods....

  1. Renormalisation group flows for gauge theories in axial gauges

    CERN Document Server

    Litim, Daniel F; Litim, Daniel F.; Pawlowski, Jan M.

    2002-01-01

    Gauge theories in axial gauges are studied using Exact Renormalisation Group flows. We introduce a background field in the infrared regulator, but not in the gauge fixing, in contrast to the usual background field gauge. It is shown how heat-kernel methods can be used to obtain approximate solutions to the flow and the corresponding Ward identities. Expansion schemes are discussed, which are not applicable in covariant gauges. As an application, we derive the one-loop effective action for covariantly constant field strength, and the one-loop beta-function for arbitrary regulator.

  2. Axial and Radial Gas Holdup in Bubble Column Reactor

    International Nuclear Information System (INIS)

    Wagh, Sameer M.; Ansari, Mohashin E Alan; Kene, Pragati T.

    2014-01-01

    Bubble column reactors are considered the reactor of choice for numerous applications including oxidation, hydrogenation, waste water treatment, and Fischer-Tropsch (FT) synthesis. They are widely used in a variety of industrial applications for carrying out gas-liquid and gas-liquid-solid reactions. In this paper, the computational fluid dynamics (CFD) model is used for predicting the gas holdup and its distribution along radial and axial direction are presented. Gas holdup increases linearly with increase in gas velocity. Gas bubbles tends to concentrate more towards the center of the column and follows a wavy path

  3. Time Dependent and Steady Uni-axial Elongational Viscosity

    DEFF Research Database (Denmark)

    Nielsen, Jens K.; Rasmussen, Henrik Koblitz; Hassager, Ole

    2005-01-01

    Here we present measurements of transient and steady uni-axial elongational viscosity, using the Filament Stretching Rheometer1 or FSR1 (see Fig. 1) of the following melts: Four narrow MMD polystyrene (PS) samples with weight-average molar mass Mw in the range of 50k to 390k. Three different bi......-disperse samples, mixed from the narrow MMD PS. Two low-density polyethylene (LDPE) melts (Lupolen 1840D and 3020D). A steady-state viscosity was kept for 1-2.5 Hencky strain units in all measurements....

  4. Plasticity around an Axial Surface Crack in a Cylindrical Shell

    DEFF Research Database (Denmark)

    Krenk, Steen

    1979-01-01

    field in an axially cracked cylindrical shell arising from use of classical eighth order shallow shell theory is removed when use is made of a tenth order shell theory which accounts for transverse shear deformations. Although the membrane stresses are only moderately affected, the influence...... and Ratwani,3–5 it generalises Dugdale's assumption of a concentrated yield zone in the plane of the crack but, contrary to that model, transverse shear effects are included and a continuous stress distribution is assumed in the yield zone. The inherent difficulties arising from the use of shell theory...

  5. Axial gravitational waves in FLRW cosmology and memory effects

    Science.gov (United States)

    Kulczycki, Wojciech; Malec, Edward

    2017-09-01

    We show initial data for gravitational axial waves that are twice differentiable but that are not C2. They generate wave pulses that interact with matter in the radiation cosmological era. This forces the radiation matter to rotate. This rotation is permanent—it persists after the passage of the gravitational pulse. The observed inhomogeneities of the cosmic microwave background radiation put a bound onto discontinuities of superhorizon metric perturbations. We explicitly show that a class of smooth initial metrics that are at least C2 gives rise to gravitational wave pulses that do not interact with the background during the radiation epoch.

  6. Static Tension Tests on Axially Loaded Pile Segments in Sand

    DEFF Research Database (Denmark)

    Thomassen, Kristina; Andersen, Lars Vabbersgaard; Ibsen, Lars Bo

    This paper provides laboratory test results of static axially loaded piles in sand. With a newly developed test setup, the pile-soil interface friction was investigated by using an open-ended steel pile segment with a diameter of 0.5 m. Use of a pile length of 1 m enabled the pile-soil interface...... friction to be analyzed at a given soil horizon while increasing the vertical effective stress in the sand. Test results obtained by this approach can be analyzed as single t-z curves and compared to predictions of unit shaft friction from current design methods for offshore foundations. The test results...

  7. Parametric design of tri-axial nested Helmholtz coils.

    Science.gov (United States)

    Abbott, Jake J

    2015-05-01

    This paper provides an optimal parametric design for tri-axial nested Helmholtz coils, which are used to generate a uniform magnetic field with controllable magnitude and direction. Circular and square coils, both with square cross section, are considered. Practical considerations such as wire selection, wire-wrapping efficiency, wire bending radius, choice of power supply, and inductance and time response are included. Using the equations provided, a designer can quickly create an optimal set of custom coils to generate a specified field magnitude in the uniform-field region while maintaining specified accessibility to the central workspace. An example case study is included.

  8. Nonlinear vibration of an axially loaded beam carrying rigid bodies

    Directory of Open Access Journals (Sweden)

    O. Barry

    2016-12-01

    Full Text Available This paper investigates the nonlinear vibration due to mid-plane stretching of an axially loaded simply supported beam carrying multiple rigid masses. Explicit expressions and closed form solutions of both linear and nonlinear analysis of the present vibration problem are presented for the first time. The validity of the analytical model is demonstrated using finite element analysis and via comparison with the result in the literature. Parametric studies are conducted to examine how the nonlinear frequency and frequency response curve are affected by tension, rotational inertia, and number of intermediate rigid bodies.

  9. Research on a novel axial-flux magnetic-field-modulated brushless double-rotor machine with low axial force and high efficiency

    Directory of Open Access Journals (Sweden)

    Chengde Tong

    2017-05-01

    Full Text Available The axial-flux magnetic-field-modulated brushless double-rotor machine (MFM-BDRM is a possible alternative as a power-split device for hybrid electric vehicles (HEVs. However, the existence of large axial force may lead to assembly problems and rich inner air-gap harmonics could result in high PM loss and low efficiency. This paper proposes a novel axial-flux MFM-BDRM with improved PM rotor structure. 2-D analytical method to predict the magnetic-field distribution of the proposed MFM-BDRM is developed and the design procedure of the proposed machine is illustrated. The impact of key geometrical parameters on axial force and torque is investigated. To evaluate the advantage of the proposed machine, a comparison is made with a conventional one with respect to electromagnetic performances. Results show that the proposed machine is effective in reducing PM eddy loss and axial force by 60% and 35%, respectively.

  10. Detection of diabetic foveal edema with biomicroscopy, fluorescein angiography and optical coherence tomography Detecção do edema foveal diabético com biomicroscopia, angiografia fluoresceínica e tomografia de coerência óptica

    Directory of Open Access Journals (Sweden)

    Rosana Zacarias Hannouche

    2008-10-01

    Full Text Available To describe different techniques for the detection of diabetic foveal edema. A retrospective review of the detection of diabetic foveal edema. Noncontact lens biomicroscopy is relatively insensitive in mild foveal thickening apparent on optical coherence tomography. Optical coherence tomography measurements can detect early retinal damage in diabetic retinopathy patients.Descrever diferentes técnicas para detecção do edema foveal diabético. Uma revisão da detecção do edema foveal diabético. Biomicroscopia com lente de não contato é relativamente insensível em edema leve aparente na tomografia de coerência óptica. Tomografia de coerência óptica pode detectar precocemente o dano retiniano inicial em pacientes com retinopatia diabética.

  11. Competition between modes with different axial structures in gyrotrons

    International Nuclear Information System (INIS)

    Khutoryan, Eduard M.; Nusinovich, Gregory S.; Sinitsyn, Oleksandr V.

    2014-01-01

    This study was motivated by some experiments in which it was found that during the voltage rise, instead of expected excitation of a high-frequency parasitic mode, the excitation of a lower-frequency parasitic mode takes place in a certain range of voltages. For explaining this fact, the dependence of start currents of possible competing modes on the beam voltage was carried out in the cold-cavity approximation and by using the self-consistent approach. It was found that in the case of cavities, which consist of the combination of a section of constant radius waveguide and a slightly uptapered waveguide, these two approaches yield completely different results. Thus, experimentally observed excitation of the low-frequency parasitic mode can be explained by the self-consistent modification of the axial profile of the excited field, which has strong influence on the diffractive quality factor of competing modes. This modification is especially pronounced in the case of excitation of modes with many axial variations which can be excited in the region of beam interaction with the backward-wave component of such modes

  12. Spine labeling in axial magnetic resonance imaging via integral kernels.

    Science.gov (United States)

    Miles, Brandon; Ben Ayed, Ismail; Hojjat, Seyed-Parsa; Wang, Michael H; Li, Shuo; Fenster, Aaron; Garvin, Gregory J

    2016-12-01

    This study investigates a fast integral-kernel algorithm for classifying (labeling) the vertebra and disc structures in axial magnetic resonance images (MRI). The method is based on a hierarchy of feature levels, where pixel classifications via non-linear probability product kernels (PPKs) are followed by classifications of 2D slices, individual 3D structures and groups of 3D structures. The algorithm further embeds geometric priors based on anatomical measurements of the spine. Our classifier requires evaluations of computationally expensive integrals at each pixel, and direct evaluations of such integrals would be prohibitively time consuming. We propose an efficient computation of kernel density estimates and PPK evaluations for large images and arbitrary local window sizes via integral kernels. Our method requires a single user click for a whole 3D MRI volume, runs nearly in real-time, and does not require an intensive external training. Comprehensive evaluations over T1-weighted axial lumbar spine data sets from 32 patients demonstrate a competitive structure classification accuracy of 99%, along with a 2D slice classification accuracy of 88%. To the best of our knowledge, such a structure classification accuracy has not been reached by the existing spine labeling algorithms. Furthermore, we believe our work is the first to use integral kernels in the context of medical images. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Axial length of atomic bomb survivors in Nagasaki

    International Nuclear Information System (INIS)

    Wakiyama, Harumi; Kishikawa, Yasuhiro; Imamura, Naoki; Amemiya, Tsugio

    2002-01-01

    We reviewed a series of 778 patients who had cataract surgery during the past 4 years at the Nagasaki Atomic Bomb Memorial Hospital. We evaluated the history of exposure to radiation by atomic bomb in 1945, axial length and state of refraction. All were born before 1945. The series comprised 263 males and 515 females. Their ages averaged 76.5±8.6 years. History of exposure to radiation was present in 356 patients. The remaining 422 patients served as control. There was no difference in the type of cataract between the two groups. High myopia was present in 11 irradiated patients (3.2%) and in 24 patients in the control group (6.0%). The difference was not significant (p=0.083). There was no high myopia among 24 patients who were aged 18 years or less at the time of radiation and who were within 2 km from the epicenter. No difference was present regarding the axial length between the two groups or between both sexes. The present result is not definitive because ''irradiated group'' would include those with little or no exposure and because precise data has not been available about the dosis of radiation. (author)

  14. Axial anomaly and index theorem for Dirac-Kaehler fermions

    International Nuclear Information System (INIS)

    Fonseca Junior, C.A.L. da.

    1985-02-01

    Some aspects of topological influence on gauge field theory are analysed, considering the geometry and differential topology methods. A review of concepts of differential forms, fibered spaces, connection and curvature, showing an interpretation of gauge theory in this context, is presented. The question of fermions, analysing in details the Dirac-Kaehler which fermionic particle is considered a general differential form, is studied. It is shown how the explicit expressions in function of the Dirac spinor components vary with the Dirac matrix representation. The Dirac-Kahler equation contains 4 times (in 4 dimensions) the Dirac equation, each particle being associated an ideal at left of the algebra of general differential forms. These ideals and the SU(4) symmetry among them are also studied on the point of view of spinors and, the group of reduction to one of the ideals is identified as the Cartan subalgebra of this SU(4). Finally, the axial anomaly is calculated through the functional determinant given by the Dirac-Kaehler operator. The regularization method is the Seeley's coefficients. From that results a comparison of the index theorems for the twisted complexes of signature and spin, which proportionality is given by the number of the algebra ideals contained in the Dirac-Kaehler equation and which also manifests in the respective axial anomaly equations. (L.C.) [pt

  15. Axial and parity anomalies and vacuum charge: A direct approach

    International Nuclear Information System (INIS)

    Boyanovsky, D.; Blankenbecler, R.

    1985-01-01

    We study the axial and parity anomalies in Abelian gauge theories using the direct yet intuitive approach of counting the relative number of states of one chirality with respect to the other. A fundamental gauge-invariant quantity, the determinantal ratio, is introduced for this purpose. We find that the number of states is conserved and that the gauge fields differentially phase shift states of opposite chirality at infinite energies. This implies a relative flow of states at very large energies which must be compensated by a rearrangement of the density of states at finite energies. We then derive a sum rule which yields two alternative formulas for the index of a Dirac operator. One expresses the index in terms of its high-energy behavior, and the other in terms of the low-energy properties; these are the ''zero modes'' of definite chirality. Two examples are worked out in detail to clarify our general result. The physics of the axial anomaly is shown to translate into that of the parity anomaly in 2+1 dimensions, in which parity and chirality have interchanged roles. We also analyze the vacuum charge in regard to its high- and low-energy origin. The possibility of spectral flow is formulated and briefly discussed. In short, we provide a physical interpretation of certain mathematical indices, relate them to an extended version of Levinson's theorem of potential scattering, and simplify their evaluation

  16. Axial U(1) current in Grabowska and Kaplan's formulation

    Science.gov (United States)

    Hamada, Yu; Kawai, Hikaru

    2017-06-01

    Recently, Grabowska and Kaplan [Phys. Rev. Lett. 116, 211602 (2016); Phys. Rev. D 94, 114504 (2016)] suggested a nonperturbative formulation of a chiral gauge theory, which consists of the conventional domain-wall fermion and a gauge field that evolves by gradient flow from one domain wall to the other. We introduce two sets of domain-wall fermions belonging to complex conjugate representations so that the effective theory is a 4D vector-like gauge theory. Then, as a natural definition of the axial-vector current, we consider a current that generates simultaneous phase transformations for the massless modes in 4 dimensions. However, this current is exactly conserved and does not reproduce the correct anomaly. In order to investigate this point precisely, we consider the mechanism of the conservation. We find that this current includes not only the axial current on the domain wall but also a contribution from the bulk, which is nonlocal in the sense of 4D fields. Therefore, the local current is obtained by subtracting the bulk contribution from it.

  17. Nanowelding configuration between carbon nanotubes in axial direction

    International Nuclear Information System (INIS)

    Cui Jianlei; Yang Lijun; Wang Yang

    2013-01-01

    Highlights: ► Nanowelding process could be accomplished at a lower temperature than the melting point of the bulk solder. ► CNTs are connected with solder joints of nodule shape. ► Some silver atoms are captured and dragged into carbon nanotube to form the core filling structures of nanowires. ► Some silver atoms diffuse along the outer walls of SWNTs with the dominant mechanism of capillary wetting. - Abstract: Interconnect technology of carbon nanotubes (CNTs) is essential for functional devices. However, difficulty in the fabrication of the interface between carbon nanotube (CNT) and CNT in axial direction, hindered the quality of connection and practical applications of electrical devices. Also, investigation of dynamic evolution of connection configuration about nanowelding is still lacking. In order to analyze the nanowelding configuration between CNTs in axial direction, the different connection cases are investigated using molecular dynamics simulation. Simulation results show that the nanowelding process could be accomplished at a lower temperature than the melting point of the bulk solder and the CNTs are connected with solder joints of nodule shape. It is also found that metal atoms are captured and dragged into nanotube to form the core filling structures of nanowires during nanowelding. Also, the connection configuration shows that Ag atoms diffuse along the outer walls of SWNTs with the dominant mechanism of capillary wetting, which would increase the contact length to improve the mechanical strength.

  18. Axial Ge/Si nanowire heterostructure tunnel FETs.

    Energy Technology Data Exchange (ETDEWEB)

    Dayeh, Shadi A. (Los Alamos National Laboratory); Gin, Aaron V.; Huang, Jian Yu; Picraux, Samuel Thomas (Los Alamos National Laboratory)

    2010-03-01

    Axial Ge/Si heterostructure nanowires (NWs) allow energy band-edge engineering along the axis of the NW, which is the charge transport direction, and the realization of asymmetric devices for novel device architectures. This work reports on two significant advances in the area of heterostructure NWs and tunnel FETs: (i) the realization of 100% compositionally modulated Si/Ge axial heterostructure NWs with lengths suitable for device fabrication and (ii) the design and implementation of Schottky barrier tunnel FETs on these NWs for high-on currents and suppressed ambipolar behavior. Initial prototype devices with 10 nm PECVD SiN{sub x} gate dielectric resulted in a very high current drive in excess of 100 {micro}A/{micro}m (I/{pi}D) and 10{sup 5} I{sub on}/I{sub off} ratios. Prior work on the synthesis of Ge/Si axial NW heterostructures through the VLS mechanism have resulted in axial Si/Si{sub 1-x}Ge{sub x} NW heterostructures with x{sub max} {approx} 0.3, and more recently 100% composition modulation was achieved with a solid growth catalyst. In this latter case, the thickness of the heterostructure cannot exceed few atomic layers due to the slow axial growth rate and concurrent radial deposition on the NW sidewalls leading to a mixture of axial and radial deposition, which imposes a big challenge for fabricating useful devices form these NWs in the near future. Here, we report the VLS growth of 100% doping and composition modulated axial Ge/Si heterostructure NWs with lengths appropriate for device fabrication by devising a growth procedure that eliminates Au diffusion on the NW sidewalls and minimizes random kinking in the heterostructure NWs as deduced from detailed microscopy analysis. Fig. 1 a shows a cross-sectional SEM image of epitaxial Ge/Si axial NW heterostructures grown on a Ge(111) surface. The interface abruptness in these Ge/Si heterostructure NWs is of the order of the NW diameter. Some of these NWs develop a crystallographic kink that is {approx

  19. Factors influencing surgical complications of intra-axial brain tumours.

    Science.gov (United States)

    Brell, M; Ibáñez, J; Caral, L; Ferrer, E

    2000-01-01

    Extensive surgical resection remains nowadays the best treatment available for most intra-axial brain tumours. However, postoperative sequelae can outweigh the potential benefits of surgery. The goal of this study has been to review the results of this treatment in our Department in order to quantify morbidity and mortality and determine predictive risk factors for each patient. We report a retrospective study of 200 patients submitted to a craniotomy for intra-axial brain tumours including gliomas and metastases. Postoperative major complications are analysed and related to different variables. An exhaustive review of the literature concerning the main controversial points about primary and metastatic brain tumours surgery is done. The overall major complication rate was 27.5%, with neurological complications being the most frequently encountered. We did not find a statistically significant relation between them and the grade of eloquence of the tumoural area. Infratentorial tumour location, previous radiotherapy and reoperations were factors strongly related to the incidence of regional complications. Age over 60 and severe concomitant disease were risk factors for systemic complications. The results from published series concerning surgical complications after craniotomies for brain tumours are not comparable because of the lack of homogeneity between them. The knowledge of the complications rate in each particular neurosurgical department turns out essentially to provide the patient with tailored information about risks before surgery.

  20. Comprometimento órbito-craniano por tumores malignos sinonasais: estudo por tomografia computadorizada Sinonasal malignant tumors involvement of the orbit and skull: a computed tomography study

    Directory of Open Access Journals (Sweden)

    Ana Célia Baptista

    2002-10-01

    Full Text Available Tumores malignos das cavidades sinonasais são raros e freqüentemente diagnosticados em estágio avançado da doença. A extensão destes tumores para locais críticos como a órbita e o crânio gera dificuldades no tratamento destas lesões. Dez pacientes com neoplasia maligna sinonasal, sem qualquer tratamento prévio e com evidência radiológica de extensão órbito-craniana, foram estudados por tomografia computadorizada. Dos dez tumores, cinco (50% foram neoplasias epiteliais, tendo sido a mais comum o carcinoma epidermóide (três casos. O sítio de origem tumoral mais comum foi o seio etmoidal, em quatro pacientes (40%, seguido pelo seio maxilar (30% e pela fossa nasal (30%. Dezesseis órbitas foram comprometidas, já que seis pacientes (60% apresentaram acometimento orbitário tumoral bilateral. Os tumores se estenderam mais freqüentemente para as órbitas através de erosão da parede medial e do soalho orbitários. A maioria das órbitas teve todos os compartimentos acometidos. Extensão dos tumores para a cavidade craniana foi mais comum através do teto etmoidal (70% e teto orbitário (30%. A fossa craniana anterior foi acometida em oito casos (80%, seguida pela fossa craniana média (40% e pelo lobo frontal (excluindo-se a fossa anterior (30%. Trinta e sete regiões da face foram acometidas pelos dez tumores, excluindo-se o sítio de origem da neoplasia e a região órbito-craniana, corroborando a grande extensão loco-regional do tumor no momento do diagnóstico.Malignant tumors of the sinonasal cavities are rare and often diagnosed late in the course of the disease. These tumors can extend into regions such as the orbit and brain, where treatment is difficult. Ten patients with nontreated sinonasal malignant neoplasms and radiological evidence of tumor extension into the orbit and brain were studied with computed tomography. Five (50% tumors were epithelial neoplasms whereas squamous cell carcinoma was the most common type (3

  1. Análise por tomografia computadorizada do enxerto autógeno na cirurgia de "sinus lift" Computed tomography evaluation of autogenous graft in sinus lift surgery

    Directory of Open Access Journals (Sweden)

    Sérgio Aron Ajzen

    2005-02-01

    Full Text Available OBJETIVO: Quantificar a formação óssea nos enxertos com e sem plasma rico em plaquetas, obtido pelos métodos de centrifugação e aférese, comparando os três tipos de enxertos realizados por meio de análise tomográfica. MATERIAIS E MÉTODOS: Este estudo prospectivo, duplo cego, utilizou uma amostra composta de 34 pacientes adultos, de ambos os sexos, com idade média de 48 anos e 8 meses, portadores de pneumatização unilateral ou bilateral dos seios maxilares, que necessitavam de enxertos ósseos, com a finalidade de melhorar as condições locais para a colocação dos implantes dentários. Todos os pacientes realizaram tomografia computadorizada antes da cirurgia. Foram operados 53 seios maxilares, divididos em três grupos: enxerto de plasma rico em plaquetas obtido pelos métodos de aférese, centrifugação e enxerto apenas de osso autógeno. Após seis meses do procedimento cirúrgico foram realizados novos exames de imagem. RESULTADOS: Pela avaliação tomográfica, houve crescimento em altura e em largura nos três grupos quando foram comparados os momentos inicial e final, entretanto, não houve diferença estatística para a altura e para a largura. CONCLUSÃO: Evidências clínicas demonstram a eficácia dos enxertos autógenos, principalmente os associados a fatores indutores de crescimento ósseo, como o plasma rico em plaquetas, recuperando o arcabouço maxilofacial, necessário para a reconstrução protética e funcional por meio de implantes dentários.OBJECTIVE: To quantify bone formation within autogenous bone grafts and autogenous bone grafts in combination with platelet-rich plasma obtained either from aphaeresis or centrifugation using computed tomography. MATERIALS AND METHODS: This prospective, double-blind study was conducted in 34 male and female adult patients (mean age of 28 years and 8 months, with either unilateral or bilateral pneumatization of the maxillary sinuses, requiring bone graft for dental

  2. Tomografia computadorizada de abdome normal: estudo retrospectivo das angulações dos hilos renais Normal abdominal computed tomography: a retrospective study of renal hila angles

    Directory of Open Access Journals (Sweden)

    Makoto Sakate

    2009-02-01

    Full Text Available OBJETIVO: Obter valores da angulação média dos hilos renais em relação ao plano horizontal, traçado sobre músculos eretores da espinha direito e esquerdo, considerando como parâmetro de referência para as medidas das angulações o centro da coluna vertebral lombar. MATERIAIS E MÉTODOS: Foram analisados 250 exames de tomografia computadorizada de abdomes considerados normais de indivíduos de ambos os sexos, sendo 128 masculinos (idade média de 52,45 ± 17,42 anos e 122 femininos (idade média de 54,39 ± 18,27 anos, totalizando 500 hilos renais estudados. A angulação média de cada hilo renal em relação ao plano horizontal foi obtida, sendo considerados sempre os ângulos agudos. RESULTADOS: O estudo comparativo entre os sexos mostrou que não houve diferença estatisticamente significante em relação aos ângulos agudos dos hilos renais. A análise estatística mostrou, com intervalo de confiança de 95%, para média do ângulo direito os limites de 40,40° e 44,54° e para o hilo renal esquerdo os limites de 39,91° e 43,23°. CONCLUSÃO: Os hilos renais, independentemente do sexo, apresentam angulações semelhantes. Valores angulares maiores terão anomalia de hiper-rotação ou hiper-rotação exagerada e valores menores terão anomalia de rotação incompleta ou rotação invertida.OBJECTIVE: To obtain mean angulation values for renal hila in relation to the horizontal plane traced over the right and left spinal erector muscles, considering the center of the lumbar vertebral spine as a parameter for measuring the renal hila angles. MATERIALS AND METHODS: The authors have analyzed 250 abdominal computed tomography studies of both male and female healthy individuals (128 men with mean age 52.45 ± 17.42 years, and 122 women with mean age 54.39 ± 18.27 years, corresponding to 500 renal hila evaluated. The mean angulation of each hilum in relation to the horizontal plane was obtained taking acute angles into consideration

  3. Estimation of axial curvature of anterior sclera: correlation between axial length and anterior scleral curvature as affected by angle kappa.

    Science.gov (United States)

    Lee, Sang-Mok; Choi, Hyuk Jin; Choi, Heejin; Kim, Mee Kum; Wee, Won Ryang

    2016-10-07

    BACKGROUND: Though the development and fitting of scleral contact lenses are expanding steadily, there is no simple method to provide scleral metrics for scleral contact lens fitting yet. The aim of this study was to establish formulae for estimation of the axial radius of curvature (ARC) of the anterior sclera using ocular biometric parameters that can be easily obtained with conventional devices. A semi-automated stitching method and a computational analysis tool for calculating ARC were developed by using the ImageJ and MATLAB software. The ARC of all the ocular surface points were analyzed from the composite horizontal cross-sectional images of the right eyes of 24 volunteers; these measurements were obtained using anterior segment optical coherence tomography for a previous study (AS-OCT; Visante). Ocular biometric parameters were obtained from the same volunteers with slit-scanning topography and partial coherence interferometry. Correlation analysis was performed between the ARC at 8 mm to the axis line (ARC[8]) and other ocular parameters (including age). With ARC obtained on several nasal and temporal points (7.0, 7.5, 8.0, 8.5, and 9.0 mm from the axis line), univariate and multivariate linear regression analyses were performed to develop a model for estimating ARC with the help of ocular biometric parameters. Axial length, spherical equivalent, and angle kappa showed correlations with temporal ARC[8] (tARC[8]; Pearson's r = 0.653, -0.579, and -0.341; P = 0.001, 0.015, and 0.015, respectively). White-to-white corneal diameter (WTW) and anterior chamber depth (ACD) showed correlation with nasal ARC[8] (nARC[8]; Pearson's r = -0.492 and -0.461; P = 0.015 and 0.023, respectively). The formulae for estimating scleral curvatures (tARC, nARC, and average ARC) were developed as a function of axial length, ACD, WTW, and distance from the axis line, with good determinant power (72 - 80 %; SPSS ver. 22.0). Angle kappa showed strong

  4. The effects of initial rise and axial loads on MEMS arches

    KAUST Repository

    Tella, Sherif Adekunle

    2017-04-07

    Arch microbeams have been utilized and proposed for many uses over the past few years due to their large tunability and bistability. However, recent experimental data have shown different mechanical behavior of arches when subjected to axial loads. This paper aims to investigate in depth the influence of the competing effects of initial rise and axial loads on the mechanical behavior of micromachined arches; mainly their static deflection and resonant frequencies. Based on analytical solutions, the static response and eigenvalue problems are analyzed for various values of initial rises and axial loads. Universal curves showing the variation of the first three resonance frequencies of the arch are generated for various values of initial rise under both tensile and compressive axial loads. This study shows that increasing the tensile or compressive axial loads for different values of initial rise may lead to either increase in the stiffness of the beam or initial decrease in the stiffness, which later increases as the axial load is increased depending on the dominant effect of the initial rise of the arch and the axial load. The obtained universal curves represent useful design tools to predict the tunability of arches under axial loads for various values of initial rises. The use of the universal curves is demonstrated with an experimental case study. Analytical formulation is developed to predict the point of minimum where the trend of the resonance frequency versus axial loads changes qualitatively due to the competing effects of axial loads and initial curvature.

  5. Complicações pulmonares após uso de crack: achados na tomografia computadorizada de alta resolução do tórax Pulmonary complications of crack cocaine use: high-resolution computed tomography of the chest

    Directory of Open Access Journals (Sweden)

    Alexandre Mançano

    2008-05-01

    Full Text Available Relatamos os achados na tomografia computadorizada de alta resolução de um paciente que, após uso de cocaína fumada (crack, desenvolveu quadro de hemoptise, dispnéia e dor torácica súbitas. As radiografias de tórax mostravam consolidações predominando em lobos superiores. A tomografia de alta resolução evidenciava opacidades em vidro fosco, consolidações e nódulos do espaço aéreo. Nova tomografia de controle, após suspensão da droga e uso de corticóides, mostrou regressão parcial das lesões e aparecimento de escavações. A correlação entre os achados clínicos, laboratoriais e de imagem permitiu o diagnóstico de "pulmão de crack".Here, we report high-resolution computed tomography (HRCT findings in a patient who developed sudden hemoptysis, dyspnea and chest pain after smoking crack cocaine. Chest X-rays showed consolidations, primarily in the upper lobes, and HRCT scans showed ground glass attenuation opacities, consolidations and air-space nodules. A follow-up CT, after drug use discontinuation and administration of corticosteroids, showed partial resolution of pulmonary lesions and the appearance of cavitations. Clinical, imaging and laboratory findings led to a diagnosis of 'crack lung'.

  6. Uso da tomografia por impedância elétrica torácica como ferramenta de auxílio às manobras de recrutamento alveolar na síndrome do desconforto respiratório agudo: relato de caso e breve revisão da literatura

    Directory of Open Access Journals (Sweden)

    Regis Goulart Rosa

    2015-12-01

    Full Text Available RESUMO A tomografia por impedância elétrica torácica constitui ferramenta de monitorização não invasiva, em tempo real, da distribuição regional da ventilação pulmonar. Sua utilização à beira do leito em pacientes com síndrome do desconforto respiratório agudo tem o potencial de auxiliar na condução de manobras de recrutamento alveolar, frequentemente necessárias em casos de hipoxemia refratária. Neste relato de caso, apresentamos os resultados e a interpretação da monitorização da tomografia por impedância elétrica torácica em um paciente com síndrome do desconforto respiratório agudo, durante manobras de recrutamento alveolar, com aplicação transitória de altas pressões alveolares e titulação da pressão positiva ao final da expiração ideal. Adicionalmente, apresentamos uma breve revisão da literatura a respeito do uso de manobras de recrutamento alveolar e monitorização com tomografia por impedância elétrica torácica em pacientes com síndrome do desconforto respiratório agudo.

  7. Tumores intracranianos em pacientes encaminhados para estudos por tomografia de coerência óptica como portadores de glaucoma sem hipertensão ocular: relato de dois casos Intracranial tumors in patients referred for optical coherence tomography examination as glaucoma suspects: case report

    Directory of Open Access Journals (Sweden)

    Laurentino Biccas Neto

    2009-10-01

    Full Text Available A tomografia de coerência óptica (OCT tem se mostrado muito útil na avaliação de pacientes com glaucoma. São relatadas duas pacientes referidas com a suspeita de glaucoma sem hipertensão para avaliação por tomografia de coerência óptica que, na verdade, eram portadoras de tumores intracranianos - um cordoma de clivo no primeiro caso e um craniofaringeoma no segundo. Os achados à tomografia de coerência óptica - diminuição difusa da espessura da camada de fibras nervosas circumdiscais desproporcionalmente acentuada nos setores nasal e temporal - levantaram a suspeita de acometimento na região do quiasma e permitiram o diagnóstico destes importantes tumores intracranianos.Optical coherence tomography (OCT has proved to be a very valuable tool in the assessment of patients with glaucoma. In this report, intracranial tumors were discovered in two glaucoma suspects referred for diagnostic confirmation by OCT - a clivus chordoma and a craniopharyngeoma. Optical coherence tomography findings - marked asymmetrical diffuse attenuation of the peripapillary nerve fiber layer in nasal and temporal sectors - raised concerns about lesions in chiasmatic region and permitted the timely diagnosis of these intraocular tumors.

  8. Cyclic Axial-Torsional Deformation Behavior of a Cobalt-Base Superalloy

    Science.gov (United States)

    Bonacuse, Peter J.; Kalluri, Sreeramesh

    1995-01-01

    The cyclic, high-temperature deformation behavior of a wrought cobalt-base super-alloy, Haynes 188, is investigated under combined axial and torsional loads. This is accomplished through the examination of hysteresis loops generated from a biaxial fatigue test program. A high-temperature axial, torsional, and combined axial-torsional fatigue database has been generated on Haynes 188 at 760 C. Cyclic loading tests have been conducted on uniform gage section tubular specimens in a servohydraulic axial-torsional test rig. Test control and data acquisition were accomplished with a minicomputer. The fatigue behavior of Haynes 188 at 760 C under axial, torsional, and combined axial-torsional loads and the monotonic and cyclic deformation behaviors under axial and torsional loads have been previously reported. In this paper, the cyclic hardening characteristics and typical hysteresis loops in the axial stress versus axial strain, shear stress ,versus engineering shear strain, axial strain versus engineering shear strain. and axial stress versus shear stress spaces are presented for cyclic in-phase and out-of-phase axial-torsional tests. For in-phase tests, three different values of the proportionality constant lambda (the ratio of engineering shear strain amplitude to axial strain amplitude, are examined, viz. 0.86, 1.73, and 3.46. In the out-of-phase tests, three different values of the phase angle, phi (between the axial and engineering shear strain waveforms), are studied, viz., 30, 60, and 90 degrees with lambda equals 1.73. The cyclic hardening behaviors of all the tests conducted on Haynes 188 at 760 C are evaluated using the von Mises equivalent stress-strain and the maximum shear stress-maximum engineering shear strain (Tresca) curves. Comparisons are also made between the hardening behaviors of cyclic axial, torsional, and combined in-phase (lambda = 1.73 and phi = 0) and out-of-phase (lambda = 1.73 and phi = 90') axial-torsional fatigue tests. These comparisons

  9. Interconnection between several eye biomechanical and biometric parameters in children with axial and refractive mild myopia

    Directory of Open Access Journals (Sweden)

    T. Ye. Tsybulskaya

    2016-08-01

    Full Text Available Aim – to study the relationship of biometric and biomechanical indicators of corneoscleral capsule of the eye in children with axial and refractive mild myopia. Materials and methods. Axial myopia was diagnosed in 32 children (64 eyes, refractive myopia – 18 (36 eyes. The control group – 16 children without ophthalmic diseases (32 eyes. Eye examination: visometry, automated refractometry, biomicroscopy, ophthalmoscopy, determination of the axial length of the eyeball and corneal hysteresis. Results. Significant differences were determined in the indicators of dioptric power of the cornea: 42.2 dpt in patients with axial and 44.7 dpt with refractive myopia (p<0.05, and also difference between patients with refractive myopia and the control group, in which the diopter power of cornea was 42.6 (p<0.05. There are also significant differences in the indicators of the axial length of eyes between axial and refractive myopia – 24.5±0.64 mm and 23.1±0.43 mm (p<0.05. Significant difference with the control group in the axial length marked only in eyes with axial myopia 22.7±0.33 mm and 24.5±0.64 mm, respectively (p<0.05. Corneal hysteresis determined significantly reduced on eyes with both the axial and refractive myopia, which was significantly lower than in the indicators of emmetropic eyes of the control group 13.7 (p<0.05. Corneal hysteresis is inversely related to the axial length of the eyeball: in patients with axial myopia r -0.32, p<0.05; with refractive myopia r -0.36, p<0.05. Сorrelation between diopter power of cornea and axial length of the eyeball: r -0.53, р<0.05 in eyes with axial myopia and r -0.42, p<0.05 refractive myopia. Comparative analysis showed no significant differences between the corneal hysteresis, the axial length of the eye and the spherical component of myopia. Conclusions. In patients with axial and refractive mild myopia corneal hysteresis is reduced on average in 1.2 and 1.1 times, in comparison with

  10. Detailed measurement of the flow field in an axial transonic compressor; Mesure detaillee des ecoulements dans un compresseur axial transsonique

    Energy Technology Data Exchange (ETDEWEB)

    Fradin, C.

    1998-07-01

    The prediction of flow structure and performances of an axial transonic compressor requires accurate solvers. Taking into account the complex flow patterns, it is important to validate codes by comparing it with experimental results. It is well understood that the availability of experimental data is fundamentally important for the improvement of the solvers. An axial transonic compressor has been fitted in the ERECA test facility of ONERA. The rotor of this compressor is isolated from stators. This experimental configuration allows to obtain a steady flow into the relative frame linked to the rotor. Due to this fact, experimental tests became easier because the basic phenomena are not hidden by mutual interactions rotor-stator. Measurements have been made in a test section far upstream the rotor, to provide the inlet conditions in the computation domain. Non intrusive and fast response measurement techniques allow to obtain the detailed flow structure in several test sections located in the rotor and far downstream it. All tests were carried out at four operating conditions of the compressor. Results provide good test cases for numerical prediction methods using three-dimensional Navier-Stokes solvers. (author)

  11. Launch Lock Assemblies Including Axial Gap Amplification Devices and Spacecraft Isolation Systems Including the Same

    Science.gov (United States)

    Barber, Tim Daniel (Inventor); Hindle, Timothy (Inventor); Young, Ken (Inventor); Davis, Torey (Inventor)

    2014-01-01

    Embodiments of a launch lock assembly are provided, as are embodiments of a spacecraft isolation system including one or more launch lock assemblies. In one embodiment, the launch lock assembly includes first and second mount pieces, a releasable clamp device, and an axial gap amplification device. The releasable clamp device normally maintains the first and second mount pieces in clamped engagement; and, when actuated, releases the first and second mount pieces from clamped engagement to allow relative axial motion there between. The axial gap amplification device normally residing in a blocking position wherein the gap amplification device obstructs relative axial motion between the first and second mount pieces. The axial gap amplification device moves into a non-blocking position when the first and second mount pieces are released from clamped engagement to increase the range of axial motion between the first and second mount pieces.

  12. Test of critical heat flux with non-uniform axial power shapes in rectangle narrow channel

    International Nuclear Information System (INIS)

    Xiong Wanyu; Wang Fei; Xiao Zejun; Lu Donghua

    2007-01-01

    Critical heat flux for axial non-uniform heat flux distribution in rectangle narrow channel was studied in this report. During the test, electric heating were adopted, and the axial direction power loaded were truncation cosine distribution. The de-ionized water was heated. The test result indicated that CHF with non-uniform axial heat flux distribution was lower than CHF with uniform axial heat flux distribution. A correction factor was used to analyze the test data. The semi-empirical relation of correction factor of CHF with axial non-uniform heat flux distribution had been obtained. Comparing to the existing correction factor models, it revealed that the proposed semi-empirical relation predictive CHF with axial non-uniform heat flux distribution in rectangle narrow channel was most accurate. (authors)

  13. Precision Seismic Monitoring of Volcanic Eruptions at Axial Seamount

    Science.gov (United States)

    Waldhauser, F.; Wilcock, W. S. D.; Tolstoy, M.; Baillard, C.; Tan, Y. J.; Schaff, D. P.

    2017-12-01

    Seven permanent ocean bottom seismometers of the Ocean Observatories Initiative's real time cabled observatory at Axial Seamount off the coast of the western United States record seismic activity since 2014. The array captured the April 2015 eruption, shedding light on the detailed structure and dynamics of the volcano and the Juan de Fuca midocean ridge system (Wilcock et al., 2016). After a period of continuously increasing seismic activity primarily associated with the reactivation of caldera ring faults, and the subsequent seismic crisis on April 24, 2015 with 7000 recorded events that day, seismicity rates steadily declined and the array currently records an average of 5 events per day. Here we present results from ongoing efforts to automatically detect and precisely locate seismic events at Axial in real-time, providing the computational framework and fundamental data that will allow rapid characterization and analysis of spatio-temporal changes in seismogenic properties. We combine a kurtosis-based P- and S-phase onset picker and time domain cross-correlation detection and phase delay timing algorithms together with single-event and double-difference location methods to rapidly and precisely (tens of meters) compute the location and magnitudes of new events with respect to a 2-year long, high-resolution background catalog that includes nearly 100,000 events within a 5×5 km region. We extend the real-time double-difference location software DD-RT to efficiently handle the anticipated high-rate and high-density earthquake activity during future eruptions. The modular monitoring framework will allow real-time tracking of other seismic events such as tremors and sea-floor lava explosions that enable the timing and location of lava flows and thus guide response research cruises to the most interesting sites. Finally, rapid detection of eruption precursors and initiation will allow for adaptive sampling by the OOI instruments for optimal recording of future

  14. Three-dimensional S-wave tomography under Axial Seamount

    Science.gov (United States)

    Baillard, C.; Wilcock, W. S. D.; Arnulf, A. F.; Tolstoy, M.; Waldhauser, F.

    2017-12-01

    Axial Seamount is a submarine volcano located at the intersection of the Juande Fuca Ridge and the Cobb-Eickelberg hotspot 500 km off the coast of thenorthwestern United States. The seamount, which rises 1 km above the seafloor, ischaracterized by a shallow caldera that is elongated in the N-S direction, measure 8km by 3 km and sits on top of a 14 km by 3 km magma reservoir. Two eruptive eventsin 1998 and 2011 motivated the deployment in 2014 of a real time cabled observatorywithin the Axial caldera, as part of the Ocean Observatories Initiative (OOI).Theobservatory includes a network of seven seismometers that span the southern half ofthe caldera. Five months after the observatory came on-line in November 2014, thevolcano erupted on April 24, 2015. Well over 100,000 events were located in thevicinity of the caldera, delineating an outward dipping ring fault that extends fromnear the surface to the magma body at 2 km depth and which accommodatesinflation and deflation of the volcano.The initial earthquake locations have beenobtained with a one-dimensional velocity model but the travel time residuals suggeststrong heterogeneities. A three-dimensional P-wave velocity model, obtained bycombining multichannel and ocean bottom seismometer refraction data, is being usedto refine locations but the three-dimensional S-wave structure is presently unknown.In most mid-ocean ridge settings, the distribution of earthquakes is not conducive forjoint inversions for S-wave velocity and hypocentral parameters because there are fewcrossing ray paths but at Axial the presence of a ring fault that is seismically active atall depths on both the east and west side of the caldera, provides a reasonablegeometry for such efforts. We will present the results of joint inversions that assumethe existing three-dimensional P wave velocity model and solve for VP/VS structure andhypocentral parameters using LOTOS, an algorithm that solves the forward problemusing ray bending.The resulting model

  15. Spine and axial skeleton injuries in the National Football League.

    Science.gov (United States)

    Mall, Nathan A; Buchowski, Jacob; Zebala, Lukas; Brophy, Robert H; Wright, Rick W; Matava, Matthew J

    2012-08-01

    The majority of previous literature focusing on spinal injuries in American football players is centered around catastrophic injuries; however, this may underestimate the true number of these injuries in this athletic cohort. The goals of this study were to (1) report the incidence of spinal and axial skeleton injuries, both minor and severe, in the National Football League (NFL) over an 11-year period; (2) determine the incidence of spinal injury by injury type, anatomic location, player position, mechanism of injury, and type of exposure (practice vs game); and (3) determine the average number of practices and days missed because of injury for each injury type. Descriptive epidemiological study. All documented injuries to the cervical, thoracic, and lumbar spine; pelvis; ribs; and spinal cord were retrospectively analyzed using the NFL's injury surveillance database over a period of 11 seasons from 2000 through 2010. The data were analyzed by the number of injuries per athlete-exposure, the anatomic location and type of injury, player position, mechanism of injury, and number of days missed per injury. A total of 2208 injuries occurred to the spine or axial skeleton over an 11-season interval in the NFL, with a mean loss of 25.7 days per injury. This represented 7% of the total injuries during this time period. Of these 2208 injuries, 987 (44.7%) occurred in the cervical spine. Time missed from play was greatest for thoracic disc herniations (189 days/injury). Other injuries that had a mean time missed greater than 30 days included (in descending order) cervical fracture (120 days/injury), cervical disc degeneration/herniation (85 days/injury), spinal cord injury (77 days/injury), lumbar disc degeneration/herniation (52 days/injury), thoracic fracture (34 days/injury), and thoracic nerve injury (30 days/injury). Offensive linemen were the most likely to suffer a spinal injury, followed by defensive backs, defensive linemen, and linebackers. Blocking and tackling

  16. Metamorphosis of helical magnetorotational instability in the presence axial electric current

    OpenAIRE

    Priede, Jānis

    2014-01-01

    This paper presents numerical linear stability analysis of a cylindrical Taylor-Couette flow of liquid metal carrying axial electric current in a generally helical external magnetic field. Axially symmetric disturbances are considered in the inductionless approximation corresponding to zero magnetic Prandtl number. Axial symmetry allows us to reveal an entirely new electromagnetic instability. First, we show that the electric current passing through the liquid can extend the range of helical ...

  17. On the Application of Correction Factor for Axial Power Distribution to CHF Correlation Development

    International Nuclear Information System (INIS)

    Kim, Kang Hoon; Kim, Hong Ju; Yang, Seung Geun; Park, Eung Jun; Hwang, Sun Tack; Chung, Sun Kyo

    2005-01-01

    The axial heat flux distribution in nuclear reactors is invariably non-uniform. Thus it is very important to validate the general applicability of CHF correlation developed with limited types of axial heat flux distribution to actual situation of various axial power shapes in reactor operation. Per the recent fuel development, CHF testing is performed for chopped cosine axial heat flux distribution only. Thus it is inevitable to re-clarify the validity of correction factor for non-uniform axial heat flux distribution to support the general applicability of CHF correlation developed with data recently tested. Two ways of approach are considered to care the effects of axial power distribution in CHF correlation development. With the first method, CHF correlation is developed based on the data of uniform axial heat flux distribution only. To apply the correlation to the data of various axially non-uniform heat flux distribution, a factor such as Tong's F-factor is applied to the predicted value by the correlation itself to correct the effects of upstream memory on CHF. With the second approach, CHF correlation is developed based on whole data with the concept of equivalent uniform heat flux for the data of non-uniform axial heat flux distribution. The equivalent uniform heat flux is a measured CHF value for the data of uniform axial heat flux distribution, but it is a pseudo-CHF with a corrective factor for the data of non-uniform axial heat flux distribution. The corrective factor is applied to predict CHF for any non-uniform axial heat flux distribution

  18. Effect of flow oscillations on axial energy transport in a porous material

    Science.gov (United States)

    Siegel, R.

    1987-01-01

    The effects of flow oscillations on axial energy diffusion in a porous medium, in which the flow is continuously disrupted by the irregularities of the porous structure, are analyzed. The formulation employs an internal heat transfer coefficient that couples the fluid and solid temperatures. The final relationship shows that the axial energy transport per unit cross-sectional area and time is directly proportional to the axial temperature gradient and the square of the maximum fluid displacement.

  19. Atlanto-axial Subluxation in rheumatoid arthritis: description of a case

    International Nuclear Information System (INIS)

    Medina, Yimy F; Martinez V, Jose B; Restrepo, Jose Felix; Rondon H, Federico; Iglesias G, Antonio

    2004-01-01

    The damage of the spine by rheumatoid arthritis is multiple and a variety of affectations have been described at cervical level, being the anterior atlanto-axial subluxation and vertical subluxation the more common. However the posterior atlanto-axial subluxation has been rarely described. In this paper, we describe the case of a patient with posterior atlanto-axial subluxaction in addition to its infrequent manifestation of alteration of the lower cranial nerves as a manifestation of myelopathy

  20. Precautions against axial fan stall in reactor building to Tianwan NPP

    International Nuclear Information System (INIS)

    Liu Chunlong; Pei Junmin

    2011-01-01

    The paper introduces the mechanism and harm of rotating stall of axial fans, analyzes the necessity for prevention against axial fan stall in reactor building of Tianwan NPP, introduces the precautions, and then makes an assessment on anti-stall effect of flow separators. It can provide reference for model-selection or reconstruction of similar fans in power stations, and for operation and maintenance of axial fans. (authors)

  1. Anatomic variants of interest in endoscopic sinus surgery: role of computed tomography; Variantes anatomicas de interes en cirugia endoscopica nasosinusal. Papel de la tomografia computerizada

    Energy Technology Data Exchange (ETDEWEB)

    Alonso, S.; Arenas, J.; Fernandez, F.; Gil, S.; Guirau, M. D. [Hospital General Universitario de Alicante (Spain)

    2000-07-01

    The detailed radiological study of the anatomy of the nasal cavities and paranasal sinus is essential prior to endoscopic sinus surgery since, on the one hand, it discloses the extent of the disease and, on the other hand, it aids in the detection of the numerous anatomic variants, some of which are of great interest to the endoscopic as the lack of preoperative knowledge of them may increase the risk of complications. the objective of the present report is to review these variants, stressing those that may be associated with a greater surgical risk. Although coronal computed tomography is the technique of choice for pre endoscopy examination, certain structures and anatomic variants are better viewed in axial images. These exceptions include anterior and posterior walls of the frontal sinuses, the anatomic relationships between posterior ethmoid complex and the sphenoid sinus, the relationships between the sphenoid sinus and the optic nerve, and the detection of Onodi cells. Thus, we recommend that the radiological examination include both coronal and axial images. (Author) 16 refs.

  2. Fracture Analysis of Debonded Sandwich Columns Under Axial Compression

    DEFF Research Database (Denmark)

    May, A.; Avilés, F.; Berggreen, Christian

    A sandwich structure consists of two strong and stiff face sheets bonded to a weak low density core. The large separation between the face sheets provides increased bending rigidity and strength at low weight cost. Thus, sandwich structures frequently present better mechanical properties than...... monolithic structures of the same weight. The vast range of applications of such materials includes wind turbines, marine, and aerospace industries. In this work, geometrically nonlinear finite element analysis is conducted to investigate the fracture parameters and debond propagation of sandwich columns...... containing a face-to-core debond subjected to axial compression. Bidimensional finite element models of sandwich columns containing different size debonds centered at one face/core interface were developed and used in conjunction with linear elastic fracture mechanics to predict the stress intensity factors...

  3. A review of X-ray computed axial tomography

    International Nuclear Information System (INIS)

    Schmidt, M.

    1989-01-01

    A review of Computed axial tomography (CAT) scanning literature outlining the theoretical and practical aspects of this technique with application in both medical diagnosis and industrial non-destructive inspection (NDI) is presented. Practical aspects of CAT scanning discussed include : radiation sources, currently available spatial and contrast resolution limits and the evolution of the computerized tomography (CT) system. It was found that monochromatic gamma rays are preferred to X-rays, especially for very high density materials, and that in medical CAT scanning, the special resolution is only, 0.5 mm while spatial resolutions of less than 50μm have been achieved in NDI. An increased number of scientific and industrial applications are anticipated (e.g. for studying sintering reactions), as the capital cost of CAT scanning decreased. 13 refs., 9 figs., 2 tabs

  4. Failure Processes in Embedded Monolayer Graphene under Axial Compression

    Science.gov (United States)

    Androulidakis, Charalampos; Koukaras, Emmanuel N.; Frank, Otakar; Tsoukleri, Georgia; Sfyris, Dimitris; Parthenios, John; Pugno, Nicola; Papagelis, Konstantinos; Novoselov, Kostya S.; Galiotis, Costas

    2014-01-01

    Exfoliated monolayer graphene flakes were embedded in a polymer matrix and loaded under axial compression. By monitoring the shifts of the 2D Raman phonons of rectangular flakes of various sizes under load, the critical strain to failure was determined. Prior to loading care was taken for the examined area of the flake to be free of residual stresses. The critical strain values for first failure were found to be independent of flake size at a mean value of –0.60% corresponding to a yield stress up to -6 GPa. By combining Euler mechanics with a Winkler approach, we show that unlike buckling in air, the presence of the polymer constraint results in graphene buckling at a fixed value of strain with an estimated wrinkle wavelength of the order of 1–2 nm. These results were compared with DFT computations performed on analogue coronene/PMMA oligomers and a reasonable agreement was obtained. PMID:24920340

  5. Stress Analysis of Fuel Rod under Axial Coolant Flow

    International Nuclear Information System (INIS)

    Jin, Hai Lan; Lee, Young Shin; Lee, Hyun Seung; Park, Num Kyu; Jeon, Kyung Rok

    2010-01-01

    A pressurized water reactor(PWR) fuel assembly, is a typical bundle structure, which uses light water as a coolant in most commercial nuclear power plants. Fuel rods that have a very slender and long clad are supported by fuel assembly which consists of several spacer grids. A coolant is a fluid which flows through device to prevent its overheating, transferring the heat produced by the device to other devices that use or dissipate it. But at the same time, the coolant flow will bring out the fluid induced vibration(FIV) of fuel rods and even damaged the fuel rod. This study has been conducted to investigate the flow characteristics and nuclear reactor fuel rod stress under effect of coolant. Fluid structure interaction(FSI) analysis on nuclear reactor fuel rod was performed. Fluid analysis of the coolant which flow along the axial direction and structural analysis under effect of flow velocity were carried out under different output flow velocity conditions

  6. Computerized axial tomography in the detection of brain damage

    International Nuclear Information System (INIS)

    Cala, L.A.; Mastaglia, F.L.

    1980-01-01

    The cranial computerized axial tomography (CAT) findings in groups of patients with epilepsy, migraine, hypertension, and other general medical disorders have been reviewed to assess the frequency and patterns of focal and diffuse brain damage. In addition to demonstrating focal lesions in a proportion of patients with seizures and in patients presenting with a stroke, the CAT scan showed a premature degree of cerebral atrophy in an appreciable proportion of patients with long-standing epilepsy, hypertension and diabetes, and in some patients with migraine, valvular and ischaemic heart disease, chronic obstructive airways disease, and chronic renal failure. The value of CAT as a means of screening for brain damage in groups of individuals at risk is discussed

  7. Nonleptonic B decays to axial-vector mesons and factorization

    International Nuclear Information System (INIS)

    Laporta, V.; Nardulli, G.; Pham, T. N.

    2006-01-01

    We present an analysis of two-body B decays with a pseudoscalar (P) and an axial-vector meson (A) in the final state using factorization. We employ as inputs a limited number of experimental data, i.e. results for the B→K 1 γ, and B→K*γ radiative decays and the branching ratios for B→πρ, πK*, Kρ, Kπ nonleptonic decays. In this way we are able to compare our predictions with recent data from the Belle and BABAR collaborations on B→a 1 π and make predictions on several other B→PA decay channels, which might be used as a guide for experimental researches and as tests of factorization

  8. Predicting the Coupling Properties of Axially-Textured Materials

    Directory of Open Access Journals (Sweden)

    María E. Fuentes-Montero

    2013-10-01

    Full Text Available A description of methods and computer programs for the prediction of “coupling properties” in axially-textured polycrystals is presented. Starting data are the single-crystal properties, texture and stereography. The validity and proper protocols for applying the Voigt, Reuss and Hill approximations to estimate coupling properties effective values is analyzed. Working algorithms for predicting mentioned averages are given. Bunge’s symmetrized spherical harmonics expansion of orientation distribution functions, inverse pole figures and (single and polycrystals physical properties is applied in all stages of the proposed methodology. The established mathematical route has been systematized in a working computer program. The discussion of piezoelectricity in a representative textured ferro-piezoelectric ceramic illustrates the application of the proposed methodology. Polycrystal coupling properties, predicted by the suggested route, are fairly close to experimentally measured ones.

  9. Plasticity around an Axial Surface Crack in a Cylindrical Shell

    DEFF Research Database (Denmark)

    Krenk, Steen

    1979-01-01

    field in an axially cracked cylindrical shell arising from use of classical eighth order shallow shell theory is removed when use is made of a tenth order shell theory which accounts for transverse shear deformations. Although the membrane stresses are only moderately affected, the influence...... and Ratwani,3–5 it generalises Dugdale's assumption of a concentrated yield zone in the plane of the crack but, contrary to that model, transverse shear effects are included and a continuous stress distribution is assumed in the yield zone. The inherent difficulties arising from the use of shell theory...... of the yield zone. The model is used to analyse published test data on surface cracked pressurised pipes. The analysis consists in COD evaluation and estimate of failure as a consequence of plastic instability. A method is proposed which deals with the problem by simultaneous analysis of a number of cracks...

  10. Treatment with tumor necrosis factor inhibitors in axial spondyloarthritis

    DEFF Research Database (Denmark)

    Ciurea, A.; Weber, U.; Stekhoven, D.

    2015-01-01

    in private practices in comparison to academic centers, adherence to ASAS treatment recommendations for TNF inhibition was equally high, and similar response rates to TNF blockers were achieved in both clinical settings. (First Release Nov 1 2014; J Rheumatol 2015; 42:101-5; doi 10.3899/jrheum.140229).......Objective. To evaluate the initiation of and response to tumor necrosis factor (TNF) inhibitors for axial spondyloarthritis (axSpA) in private rheumatology practices versus academic centers. The Journal of Rheumatology, Methods.We compared newly initiated TNF inhibition for axSpA in 363 patients...... was slightly higher in the hospital setting. Mean levels (+/- SD) of the Ankylosing Spondylitis Disease Activity Score were, however, virtually identical in private practices and academic centers (3.4 +/- 1.0 vs 3.4 +/- 0.9, p = 0.68). An Assessment of SpondyloArthritis international Society (ASAS40) response...

  11. Study of axial protections of unloading machines of graphite piles

    International Nuclear Information System (INIS)

    Duco, Jacques; Pepin, Pierre; Cabaret, Guy; Dubor, Monique

    1969-10-01

    As previous studies resulted in the development of a simple calculation formula based on experimental results for the calculation of neutron protection thicknesses for loading machines, this study aimed at determining axial protections of these machines which represent a specific problem: scattering of delayed neutrons in the machine inner cavity may result in an important neutron leakage through the upper part, at the level of the winch enclosure. In an experimental part, this study comprises the measurement of the neutron dose in a 2.60 m long and 54 cm diameter cylindrical cavity, and in the thickness of the surrounding concrete protection. In the second part, the authors present a calculation method which uses the Zeus and Mercure codes to interpret the results [fr

  12. Endoscopic Transoral Resection of an Axial Chordoma: A Case Report

    Directory of Open Access Journals (Sweden)

    Taran S

    2015-11-01

    Full Text Available Upper cervical chordoma (UCC is rare condition and poses unique challenges to surgeons. Even though transoral approach is commonly employed, a minimally invasive technique has not been established. We report a 44-year old Malay lady who presented with a 1 month history of insidious onset of progressive neck pain without neurological symptoms. She was diagnosed to have an axial (C2 chordoma. Intralesional resection of the tumour was performed transorally using the Destandau endoscopic system (Storz, Germany. Satisfactory intralesional excision of the tumour was achieved. She had a posterior fixation of C1-C4 prior to that. Her symptoms improved postoperatively and there were no complications noted. She underwent adjuvant radiotherapy to minimize local recurrence. Endoscopic excision of UCC via the transoral approach is a safe option as it provides an excellent magnified view and ease of resection while minimizing the operative morbidity.

  13. Active surge control for variable speed axial compressors.

    Science.gov (United States)

    Lin, Shu; Yang, Chunjie; Wu, Ping; Song, Zhihuan

    2014-09-01

    This paper discusses active surge control in variable speed axial compressors. A compression system equipped with a variable area throttle is investigated. Based on a given compressor model, a fuzzy logic controller is designed for surge control and a proportional speed controller is used for speed control. The fuzzy controller uses measurements of the change of pressure rise as well as the change of mass flow to determine the throttle opening. The presented approach does not require the knowledge of system equilibrium or the surge line. Numerical simulations show promising results. The proposed fuzzy logic controller performs better than a backstepping controller and is capable to suppress surge at different operating points. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  14. Hamilton's equations for a fluid membrane: axial symmetry

    International Nuclear Information System (INIS)

    Capovilla, R; Guven, J; Rojas, E

    2005-01-01

    Consider a homogeneous fluid membrane, or vesicle, described by the Helfrich-Canham energy, quadratic in the mean curvature. When the membrane is axially symmetric, this energy can be viewed as an 'action' describing the motion of a particle; the contours of equilibrium geometries are identified with particle trajectories. A novel Hamiltonian formulation of the problem is presented which exhibits the following two features: (i) the second derivatives appearing in the action through the mean curvature are accommodated in a natural phase space and (ii) the intrinsic freedom associated with the choice of evolution parameter along the contour is preserved. As a result, the phase space involves momenta conjugate not only to the particle position but also to its velocity, and there are constraints on the phase space variables. This formulation provides the groundwork for a field theoretical generalization to arbitrary configurations, with the particle replaced by a loop in space

  15. Development of throughflow calculation code for axial flow compressors

    International Nuclear Information System (INIS)

    Kim, Ji Hwan; Kim, Hyeun Min; No, Hee Cheon

    2005-01-01

    The power conversion systems of the current HTGRs are based on closed Brayton cycle and major concern is thermodynamic performance of the axial flow helium gas turbines. Particularly, the helium compressor has some unique design challenges compared to the air-breathing compressor such as high hub-to-tip ratios throughout the machine and a large number of stages due to the physical property of the helium and thermodynamic cycle. Therefore, it is necessary to develop a design and analysis code for helium compressor that can estimate the design point and off-design performance accurately. KAIST nuclear system laboratory has developed a compressor design and analysis code by means of throughflow calculation and several loss models. This paper presents the outline of the development of a throughflow calculation code and its verification results

  16. Axial shape index calculation for the 3-level excore detector

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Han Gon; Kim, Yong Hee; Kim, Byung Sop; Lee, Sang Hee; Cho, Sung Jae [Korea Electric Power Research Institute, Taejon (Korea, Republic of)

    1997-12-31

    A new method based on the alternating conditional expectation (ACE) algorithm is developed to calculate axial shape index (ASI) for the 3-level excore detector. The ACE algorithm, a type of nonparametric regression algorithms, yields an optimal relationship between a dependent variable and multiple independent variables. In this study, the simple correlation between ASI and excore detector signals is developed using the Younggwang nuclear power plant unit 3 (YGN-3) data without any preprocessing on the relationships between independent variables and dependent variable. The numerical results show that simple correlations exist between the three excore signals and ASI of the core. The accuracy of the new method is much better than those of the current CPC and COLSS algorithms. 5 refs., 2 figs., 2 tabs. (Author)

  17. Structures of water molecular nanotube induced by axial tensile strains

    Energy Technology Data Exchange (ETDEWEB)

    Li, H. [Key Laboratory of Liquid Structures and Heredity of Materials, Ministry of Education, School of Materials Science and Engineering, Shandong University (China)], E-mail: lihuilmy@hotmail.com; Zhang, X.Q. [Physics Department, Ocean University of China, Qingdao (China); Liew, K.M. [Department of Building and Constructions, City University of Hong Kong, Kowloon (Hong Kong); Liu, X.F. [Key Laboratory of Liquid Structures and Heredity of Materials, Ministry of Education, School of Materials Science and Engineering, Shandong University (China)

    2008-10-06

    Five well-ordered nano-ice structures embedded in carbon nanotubes are obtained in this study. These five nano-ice phases all exhibit single walled tubular morphologies, including the pentagon, hexagon ice nanotubes whose structures are quite different from bulk ice. Our simulation results indicate that water molecules tend to rearrange into surface ring structures to reduce the number of free OH groups. The structural behavior of these ice nanotubes inside CNTs subject to axial stress is also investigated. The ice nanotubes tend to be drawn to ice nanorings or ice nanospring during the mechanical stretching. The distribution function exhibits typical order-to-disorder transition of the water network confined in carbon nanotube during the stretching. By analysis, we suggest that it is unlikely that additional water molecules will enter the tubes because of the increased volume available if the tubes are stretched at contact with a water reservoir.

  18. Axial-flow turbines for low head microhydro systems

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, K.V.; Fuller, A.M. [Department of Mechanical Engineering, University of Canterbury, PB 4800, Christchurch (New Zealand); Giddens, E.P. [Department of Civil Engineering, University of Canterbury, Christchurch (New Zealand)

    2009-01-15

    This paper describes the design of four different specific speed microhydro propeller turbines operating at heads between 4 m and 9 m, and their application to a wider range of heads and outputs by scaling. The features are specifically tailored for ease of manufacture and uniquely resistant to debris blockage. Test machines are described and test results given; hydraulic efficiencies of over 68% have been achieved in all test models despite the fact that these turbines' blades are planar, further simplifying manufacture. Theoretical models show how closely these flat blades can be made to approach the ideal blade shapes. Outline drawings are given with key dimensions for each reference model, along with the equations for scaling to arbitrary sites. These turbines are the axial flow members of a family of turbines developed to cover the microhydro range from 2 m to about 40 m of head. (author)

  19. A cryogenic axial-centrifugal compressor for superfluid helium refrigeration

    CERN Document Server

    Decker, L; Schustr, P; Vins, M; Brunovsky, I; Lebrun, P; Tavian, L

    1997-01-01

    CERN's new project, the Large Hadron Collider (LHC), will use superfluid helium as coolant for its high-field superconducting magnets and therefore require large capacity refrigeration at 1.8 K. This may only be achieved by subatmospheric compression of gaseous helium at cryogenic temperature. To stimulate development of this technology, CERN has procured from industry prototype Cold Compressor Units (CCU). This unit is based on a cryogenic axial-centrifugal compressor, running on ceramic ball bearings and driven by a variable-frequency electrical motor operating under low-pressure helium at ambient temperature. The machine has been commissioned and is now in operation. After describing basic constructional features of the compressor, we report on measured performance.

  20. Control of hole localization in magnetic semiconductors by axial strain

    Science.gov (United States)

    Raebiger, Hannes; Bae, Soungmin; Echeverría-Arrondo, Carlos; Ayuela, Andrés

    2018-02-01

    Mn and Fe-doped GaN are widely studied prototype systems for hole-mediated magnetic semiconductors. The nature of the hole states around the Mn and Fe impurities, however, remains under debate. Our self-interaction corrected density-functional calculations show that the charge neutral Mn 0 and positively charged Fe+ impurities have symmetry-broken d5+h ground states, in which the hole is trapped by one of the surrounding N atoms in a small polaron state. We further show that both systems also have a variety of other d5+h configurations, including symmetric, delocalized states, which may be stabilized by axial strain. This finding opens a pathway to promote long-range hole-mediated magnetic interactions by strain engineering and clarifies why highly strained thin-films samples often exhibit anomalous magnetic properties.

  1. Operational Experience with a Cryogenic Axial-Centrifugal Compressor

    CERN Document Server

    Decker, L; Löhlein, K; Purtschert, W; Ziegler, B L; Lebrun, P; Tavian, L; Brunovsky, I; Tucek, L

    1998-01-01

    The Large Hadron Collider (LHC), presently under construction at CERN, requires large refrigeration capacity at 1.8 K. Compression of gaseous helium at cryogenic temperatures is therefore inevitable. Together with subcontractors, Linde Kryotechnik has developed a prototype machine. This unit is based on a cryogenic axial-centrifugal compressor, running on ceramic ball bearings and driven by a variable-frequency electrical motor operating at ambient temperature. Integrated in a test facility for superconducting magnets the machine has been commissioned without major problems and successfully gone through the acceptance test in autumn 1995. Subsequent steps were initiated to improve efficiency of this prototype. This paper describes operating experience gained so far and reports on measured performance prior to and after constructional modifications.

  2. Experimental investigation of axially aligned flow past spinning cylinders

    Science.gov (United States)

    Carlucci, Pasquale; Buckley, Liam; Mehmedagic, Igbal; Carlucci, Donald; Thangam, Siva

    2016-11-01

    Experimental and numerical results of ongoing subsonic investigations of the flow field about axially aligned spinning cylinders with variable inter-cylinder spacing are presented. The experimental design is capable of investigating wake dynamics of the modeled system up to a Reynolds Number of 300,000 and rotation numbers up to 2. The experimental results are used to validate and confirm numerical simulations with and without the effects of swirl. The focus of the overall effort is an understanding of the dynamics of multi-body problems in a flow field, as such we relate the ongoing effort to previous studies by both the authors and the community at large and our ongoing work in developing accurate plant models for use in engineering analysis and design. Funded in part by U. S. Army ARDEC, Picatinny Arsenal, NJ.

  3. Computer aided hydraulic design of axial flow pump impeller

    International Nuclear Information System (INIS)

    Sreedhar, B.K.; Rao, A.S.L.K.; Kumaraswamy, S.

    1994-01-01

    Pumps are the heart of any power plant and hence their design requires great attention. Computers with their potential for rapid computation can be successfully employed in the design and manufacture of these machines. The paper discusses a program developed for the hydraulic design of axial flow pump impeller. The program, written in FORTRAN 77, is interactive and performs the functions of design calculation, drafting and generation of numerical data for blade manufacture. The drafting function, which makes use of the software ACAD, is carried out automatically by means of suitable interface programs. In addition data for blade manufacture is also generated in either the x-y-z or r-θ-z system. (author). 4 refs., 3 figs

  4. Gearbox Instrumentation for the Investigation of Bearing Axial Cracking

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Jonathan A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Lambert, Scott R [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-03-27

    Failures in gearbox bearings have been the primary source of reliability issues for wind turbine drivetrains, leading to costly downtime and unplanned maintenance. The most common failure mode is attributed to so-called axial cracks or white-etching cracks, which primarily affect the intermediate and high-speed-stage bearings. The high-speed-shaft and bearing loads and sliding will be measured with a specially instrumented gearbox installed in a 1.5-megawatt turbine at the National Wind Technology Center in an upcoming test campaign. Additional instrumentation will also measure the tribological environment of these bearings, including bearing temperatures, lubricant temperature and water content, air temperature and humidity, and stray electrical current across the bearings. This paper fully describes the instrumentation package and summarizes initial results.

  5. Axial-resolution in depth from focus digital holography

    Science.gov (United States)

    van Rooij, Joseph; Kalkman, Jeroen

    2017-06-01

    We use digital holography to quantify surface topography of rough objects in full-field. We calculate the variance of the intensity image as a focus metric over a set of reconstruction distances for each pixel, which results in a focus metric curve. The distance where the variance peaks is an estimate for the depth. First we analyze the lateral resolution of this method using the Talbot effect and argue that sub-mm axial resolution is feasible. Then, using a Michelson setup without magnifying optics or lateral scanning we experimentally demonstrate that sub-mm FWHM width of the focus curve can be achieved. This is significantly better than what was previously reported using digital holography and could make this technique useful for characterising objects in art and machine vision.

  6. Chondrocyte activity is increased in psoriatic arthritis and axial spondyloarthritis

    DEFF Research Database (Denmark)

    Gudmann, Natasja Stæhr; Munk, Heidi Lausten; Christensen, Anne Friesgaard

    2016-01-01

    BACKGROUND: Psoriatic arthritis (PsA) and axial spondyloarthritis (axSpA) are chronic inflammatory rheumatic diseases with complex origins. Both are characterized by altered extracellular matrix remodeling in joints and entheses that results in destructive and osteochondral proliferative lesions.......30 ng/ml, 0.16-0.41) (p treatment. C-Col10 was slightly but equally elevated in the PsA and axSpA groups vs. the control group, but it was significantly lower in patients with axSpA undergoing tumor necrosis factor-α inhibitor (TNFi) treatment. ROC curve......SpA undergoing TNFi treatment may reflect that hypertrophic chondrocytes in axSpA are targeted by TNFi. ROC curve analysis showed a diagnostic potential for Pro-C2 in axSpA and PsA....

  7. Dynamic Electromechanical Characterization of Axially Poled PZT 95/5

    International Nuclear Information System (INIS)

    Chhabildas, Lalit C.; Furnish, Michael D.; Montgomery, Stephen T.; Setchell, Robert E.

    1999-01-01

    We are conducting a comprehensive experimental study of the electromechanical behavior of poled PZT 95/5 (lead zirconate titanate). As part of this study, eight plane-wave tests have been conducted on axially poled PZT 95/5 at stress levels ranging from 0.9 to 4.6 GPa, using VISAR and electrical diagnostics. Observed wave velocities were slightly decreased from ultrasonic velocity, by contrast' with unpoled samples. Compression waveforms show a step at 0.6 GPa more marked than for normally poled or unpoled samples; this may correspond to a poling effect on the ferroelectric/antiferroelectric transition. A similar step is observed on release. The released charge upon loading to 0.9 GPa is consistent with nearly complete depoling. Loading to higher stresses gave lower currents (factor of 10), suggesting shock-induced conductivity or electrical breakdown

  8. Organo-axial volvulus of the small intestine: radiological case report and consideration for its mechanism.

    Science.gov (United States)

    Ishiguro, Toshitaka; Hiyama, Takashi; Nasu, Katsuhiro; Akashi, Yoshimasa; Minami, Manabu

    2017-07-01

    Gastrointestinal volvulus is mainly classified into two subtypes, mesentero-axial volvulus and organo-axial volvulus. The detailed imaging findings of organo-axial volvulus of the small intestine have never been reported as far as we know. In this article, we report a case of organo-axial volvulus of the small intestine, focusing on the computed tomography (CT) findings. An 80-year-old man was radiologically diagnosed as having organo-axial volvulus of the terminal ileum and it was confirmed by open surgery without adhesion or any other anatomical abnormalities. CT showed two specific findings, split-bowel sign and rotating-C sign, which we think reflect pathophysiologic features of organo-axial volvulus. We think the pathogenic mechanism of organo-axial volvulus can be explained by the convergence of the reversed-rotational twist following the formation of a twisted but non-obstructive circular loop, even if there is no adhesion. Radiologists should be aware that organo-axial volvulus can occur even in the small intestine, and in the case of small bowel obstruction with single transition point, the two pathophysiologic signs mentioned above must be looked for to diagnose the possibility of organo-axial volvulus.

  9. Simulations of axial B-dot monitors inside a groove in the beam pipe

    Energy Technology Data Exchange (ETDEWEB)

    He, Xiaozhong, E-mail: hexiaozhong@tsinghua.org.cn [Institute of Fluid Physics, Chinese Academy of Engineering Physics, Mianyang, Sichuan (China); Pang, Jian; Li, Qin [Institute of Fluid Physics, Chinese Academy of Engineering Physics, Mianyang, Sichuan (China); Du, Yingchao [Department of Engineering Physics, Tsinghua University, Beijing (China)

    2013-11-21

    Beam tilt measurement is important for understanding the beam dynamics. Our previous theoretical studies and simulations have shown that the axial B-dot in smooth beam pipe can be used to measure the beam tilt directly. Practical azimuthal B-dot loops typically are placed inside a groove in the beam pipe to avoid direct beam interception. For the same purpose, practical axial B-dot loops should also be placed inside such a groove. In this paper, responses of axial magnetic field to the beam tilt and to the beam offset, in the presence of the groove, are investigated by simulations. The simulation results show that the axial magnetic field in the central plane of the groove is proportional to the beam tilt and independent on the centroid position. The ratio between the axial magnetic field and the beam tilt depends on the position of the axial B-dot loop and the dimensions of the groove. -- Highlights: •MAFIA simulations were carried out to analyze the influence of recessed groove to axial B dots. •It is found that axial B dots still works in the central plane of the recessed groove. •The dimensions of the groove greatly influence the signal strength of axial B dots. •Results can be used for future optimizations.

  10. Significance of axial length monitoring in children with congenital cataract and update of measurement methods.

    Science.gov (United States)

    Zhan, Jiao; Lin, Haotian; Zhang, Xinyu; Chen, Weirong; Liu, Yizhi

    2013-06-01

    Congenital cataract is the main cause of blindness in children, with significantly varying treatment effects. The development of axial length is an important factor that affects the prognosis of these children. However, when compared with the eyes of normal children, the mechanism of growth of the axial length is so complicated that the reported findings differ significantly in terms of the measuring apparatus, assessment methods, and statistical outcome, making the rule of axial length development still unclear. In this paper, we first review the process of axial length development in normal healthy children and compare different hypotheses about certain factors that could affect the development of axial length. The results of some current research about the characteristics of axial length development in congenital cataract children are then reviewed. Lastly, the advantages and disadvantages of current axial length measurements methods are compared and analyzed. The purpose of this review is to improve our understanding of the complexity and importance of axial length development and to suggest better use of axial length monitoring measurements in congenital cataract children for pediatric ophthalmologists, with the hope of offering assistance that will enhance long-term therapeutic effects for these children.

  11. Fuel rod with axial regions of annular and standard fuel pellets

    International Nuclear Information System (INIS)

    Freeman, T.R.

    1991-01-01

    This patent describes a fuel rod for use in a nuclear reactor fuel assembly. It comprises: an elongated hollow cladding tube; a pair of end plugs connected to and sealing the cladding tube at opposite ends of thereof; and an axial stack of fuel pellets contained in and extending between the end plugs at the opposite ends of the tube, all of the fuel pellets contained in the tube being composed of fissile material being enriched above the level of natural enrichment; the fuel pellets in the stack thereof being provided in an arrangement of axial regions. The arrangement of axial regions including a pair of first axial regions defined respectively at the opposite ends of the pellet stack adjacent to the respective end plugs. The pellets in the first axial regions being identical in number and having annular configurations with an annulus of a first void size. The arrangement of axial regions also including another axial region defined between the first axial regions, some of the pellets in the another axial region having solid configurations

  12. White matter biomarkers from fast protocols using axially symmetric diffusion kurtosis imaging

    DEFF Research Database (Denmark)

    Hansen, Brian; Khan, Ahmad R.; Shemesh, Noam

    2016-01-01

    progressing diseases. Here, we evaluate WMTI based on recently introduced axially symmetric DKI which has lower data demand than conventional DKI. We compare WMTI parameters derived from conventional DKI to those from axially symmetric DKI and to parameters calculated analytically from the axially symmetric...... tensors. We also assess the effect of the imposed symmetry on the kurtosis fractional anisotropy (KFA). We employ numerical simulations, as well as data from fixed rat spinal cord and whole human brain in vivo. Our analysis shows that analytical WMTI based on axially symmetric DKI with sparse data sets...

  13. Molecular dynamics study of nanojoining between axially positioned Ag nanowires

    International Nuclear Information System (INIS)

    Cui, Jianlei; Theogene, Barayavuga; Wang, Xuewen; Mei, Xuesong; Wang, Wenjun; Wang, Kedian

    2016-01-01

    Highlights: • The temperature and distance have a great impact on joining effect without solders. • At high temperature, Ag atoms are disordered and the atomic queues become to distort. • When the distance is large, the Ag nanowires are not connected at any temperature. • When the distance is small and the temperature is low, Ag NWs on the Si substrate can be obtained relatively good nanoconnection. - Abstract: The miniaturization of electronics devices into nanometer scale is indispensable for next-generation semiconductor technology. Ag nanowires (Ag NWs) are considered to be the promising candidates for future electronic circuit owing to the excellent electrical and thermal properties. The nanojoining of axially positioned Ag NWs was performed by molecular dynamics simulation. Through the detailed atomic evolution during the nanojoining, the results indicate that the temperature and the distance between Ag NWs in axial direction have a great impact on nanojoining effect. When the nanojoining temperature is relatively high, the atoms are disordered and the atomic queues become to distort with strong thermodynamic properties and weak effect of metal bonds. At the relatively low temperature, the Ag NWs can be well connected with good junction quality and their own morphology, which is similar to the cold welding without fusion, while the distance between Ag NWs should be controlled for interaction and diffusion of interfacial atoms at nanowires head. When the Ag NWs are placed on Si and SiO 2 substrate, because the atomic species and lattice structure of substrate material can differently affect the motions of Ag atoms through the interactive force between the atoms, the nanojoining quality of Ag NWs on Si substrate is better than that on the SiO 2 substrate. So, for getting effective and reliable nanojoining without nanosolders and other materials, the temperature, distance and substrate surface should be reasonably controlled and selected, providing

  14. Molecular dynamics study of nanojoining between axially positioned Ag nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Jianlei, E-mail: cjlxjtu@xjtu.edu.cn [State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049 (China); State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433 (China); State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Theogene, Barayavuga, E-mail: 1400584887@qq.com [State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049 (China); State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433 (China); Wang, Xuewen, E-mail: 358994796@qq.com [State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049 (China); State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433 (China); Mei, Xuesong, E-mail: xsmeixjtu@163.com [State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049 (China); Wang, Wenjun, E-mail: wangwenjun1981@yeah.net [State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049 (China); Wang, Kedian, E-mail: kedianwang@yeah.net [State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049 (China)

    2016-08-15

    Highlights: • The temperature and distance have a great impact on joining effect without solders. • At high temperature, Ag atoms are disordered and the atomic queues become to distort. • When the distance is large, the Ag nanowires are not connected at any temperature. • When the distance is small and the temperature is low, Ag NWs on the Si substrate can be obtained relatively good nanoconnection. - Abstract: The miniaturization of electronics devices into nanometer scale is indispensable for next-generation semiconductor technology. Ag nanowires (Ag NWs) are considered to be the promising candidates for future electronic circuit owing to the excellent electrical and thermal properties. The nanojoining of axially positioned Ag NWs was performed by molecular dynamics simulation. Through the detailed atomic evolution during the nanojoining, the results indicate that the temperature and the distance between Ag NWs in axial direction have a great impact on nanojoining effect. When the nanojoining temperature is relatively high, the atoms are disordered and the atomic queues become to distort with strong thermodynamic properties and weak effect of metal bonds. At the relatively low temperature, the Ag NWs can be well connected with good junction quality and their own morphology, which is similar to the cold welding without fusion, while the distance between Ag NWs should be controlled for interaction and diffusion of interfacial atoms at nanowires head. When the Ag NWs are placed on Si and SiO{sub 2} substrate, because the atomic species and lattice structure of substrate material can differently affect the motions of Ag atoms through the interactive force between the atoms, the nanojoining quality of Ag NWs on Si substrate is better than that on the SiO{sub 2} substrate. So, for getting effective and reliable nanojoining without nanosolders and other materials, the temperature, distance and substrate surface should be reasonably controlled and selected

  15. Axial Magnetic Field Compression in Laboratory Plasma Jets

    Science.gov (United States)

    Byvank, Tom; Potter, William; Greenly, John; Seyler, Charles; Kusse, Bruce

    2017-10-01

    Compression of an axial magnetic field correlates with density hollowing and azimuthal rotation of a plasma jet generated by the COBRA pulsed power machine (1 MA peak current in 100 ns rise time) in a radial foil (thin disk of 15 μm Al or Ti) configuration. The plasma jet compresses an initially uniform 1 T axial magnetic field (Bz) as it collimates along the central z-axis. Experimental measurements use a Bdot magnetic probe placed in the center of the hollow plasma jet. Experimental results show compression of an applied 1.0 +/-0.1 T Bz to 2.4 +/-0.3 T with aluminum jets and to 2.2 +/-0.2 T with titanium jets. Predictions made by the extended magnetohydrodynamics (XMHD) code, PERSEUS, show compression to a 3.4 T Bz at the probe location for aluminum plasmas. For titanium plasmas, implementing radiation into the code is in progress. Additionally using the XMHD simulation, we explore the effects of changing current directions and how the magnetic field being tied to the electrons in Hall MHD (rather than being frozen to the ions in ideal MHD) influences the magnetic field advection. We overview physical reasons for the discrepancy between the experimental and simulation magnetic field compression measurements, including: surface plasma on Bdot probes, 2D and 3D simulation effects, and differences between ablation of a solid foil compared to a foil initialized as a plasma. Work supported by NNSA SSAP under DOE Cooperative Agreement DE-NA0001836 and NSF Grant PHY-1102471.

  16. Axial magnetic field injection in magnetized liner inertial fusion

    Science.gov (United States)

    Gourdain, P.-A.; Adams, M. B.; Davies, J. R.; Seyler, C. E.

    2017-10-01

    MagLIF is a fusion concept using a Z-pinch implosion to reach thermonuclear fusion. In current experiments, the implosion is driven by the Z-machine using 19 MA of electrical current with a rise time of 100 ns. MagLIF requires an initial axial magnetic field of 30 T to reduce heat losses to the liner wall during compression and to confine alpha particles during fusion burn. This field is generated well before the current ramp starts and needs to penetrate the transmission lines of the pulsed-power generator, as well as the liner itself. Consequently, the axial field rise time must exceed hundreds of microseconds. Any coil capable of being submitted to such a field for that length of time is inevitably bulky. The space required to fit the coil near the liner, increases the inductance of the load. In turn, the total current delivered to the load decreases since the voltage is limited by driver design. Yet, the large amount of current provided by the Z-machine can be used to produce the required 30 T field by tilting the return current posts surrounding the liner, eliminating the need for a separate coil. However, the problem now is the field penetration time, across the liner wall. This paper discusses why skin effect arguments do not hold in the presence of resistivity gradients. Numerical simulations show that fields larger than 30 T can diffuse across the liner wall in less than 60 ns, demonstrating that external coils can be replaced by return current posts with optimal helicity.

  17. Axial ion-electron emission microscopy of IC radiation hardness

    Science.gov (United States)

    Doyle, B. L.; Vizkelethy, G.; Walsh, D. S.; Swenson, D.

    2002-05-01

    A new system for performing radiation effects microscopy (REM) has been developed at Sandia National Laboratory in Albuquerque. This system combines two entirely new concepts in accelerator physics and nuclear microscopy. A radio frequency quadrupole (RFQ) linac is used to boost the energy of ions accelerated by a conventional Tandem Van de Graaff-Pelletron to velocities of 1.9 MeV/amu. The electronic stopping power for heavy ions is near a maximum at this velocity, and their range is ˜20 μm in Si. These ions therefore represent the most ionizing form of radiation in nature, and are nearly ideal for performing single event effects testing of integrated circuits. Unfortunately, the energy definition of the RFQ-boosted ions is rather poor (˜ a few %), which makes problematic the focussing of such ions to the submicron spots required for REM. To circumvent this problem, we have invented ion electron emission microscopy (IEEM). One can perform REM with the IEEM system without focussing or scanning the ion beam. This is because the position on the sample where each ion strikes is determined by projecting ion-induced secondary electrons at high magnification onto a single electron position sensitive detector. This position signal is then correlated with each REM event. The IEEM system is now mounted along the beam line in an axial geometry so that the ions pass right through the electron detector (which is annular), and all of the electrostatic lenses used for projection. The beam then strikes the sample at normal incidence which results in maximum ion penetration and removes a parallax problem experienced in an earlier system. Details of both the RFQ-booster and the new axial IEEM system are given together with some of the initial results of performing REM on Sandia-manufactured radiation hardened integrated circuits.

  18. Hysteretic Models Considering Axial-Shear-Flexure Interaction

    Science.gov (United States)

    Ceresa, Paola; Negrisoli, Giorgio

    2017-10-01

    Most of the existing numerical models implemented in finite element (FE) software, at the current state of the art, are not capable to describe, with enough reliability, the interaction between axial, shear and flexural actions under cyclic loading (e.g. seismic actions), neglecting crucial effects for predicting the nature of the collapse of reinforced concrete (RC) structural elements. Just a few existing 3D volume models or fibre beam models can lead to a quite accurate response, but they are still computationally inefficient for typical applications in earthquake engineering and also characterized by very complex formulation. Thus, discrete models with lumped plasticity hinges may be the preferred choice for modelling the hysteretic behaviour due to cyclic loading conditions, in particular with reference to its implementation in a commercial software package. These considerations lead to this research work focused on the development of a model for RC beam-column elements able to consider degradation effects and interaction between the actions under cyclic loading conditions. In order to develop a model for a general 3D discrete hinge element able to take into account the axial-shear-flexural interaction, it is necessary to provide an implementation which involves a corrector-predictor iterative scheme. Furthermore, a reliable constitutive model based on damage plasticity theory is formulated and implemented for its numerical validation. Aim of this research work is to provide the formulation of a numerical model, which will allow implementation within a FE software package for nonlinear cyclic analysis of RC structural members. The developed model accounts for stiffness degradation effect and stiffness recovery for loading reversal.

  19. Analysis of Mechanical Failure of Polymer Microneedles by Axial Force

    Science.gov (United States)

    Park, Jung-Hwan; Prausnitz, Mark R.

    2010-01-01

    A polymeric microneedle has been developed for drug delivery applications. The ultimate goal of the polymeric microneedle is insertion into the specified region without failure for effective transdermal drug delivery. Mechanical failure of various geometries of microneedles by axial load was modeled using the Euler formula and the Johnson formula to predict the failure force of tapered-column microneedles. These formulas were compared with measured data to identify the mechanical behavior of microneedles by determining the critical factors including the actual length and end-fixed factor. The comparison of the two formulas with the data showed good agreement at the end-fixity (K) of 0.7. This value means that a microneedle column has one fixed end and one pinned end, and that part of the microneedle was overloaded by axial load. When the aspect ratio of length to equivalent diameter is 12:1 at 3 GPa of Young’s modulus, there is a transition from the Euler region to the Johnson region by the decreased length and increased base diameter of the microneedle. A polymer having less than 3 GPa of stiffness would follow the Euler formula. A 12:1 aspect ratio of length to equivalent diameter of the microneedle was the mechanical indicator determining the failure mode between elastic buckling and inelastic buckling at less than 3 GPa of Young’s modulus of polymer. Microneedles with below a 12:1 aspect ratio of length-to-equivalent diameter and more than 3 GPa of Young’s were recommended for reducing sudden failure by buckling and for successfully inserting the microneedle into the skin. PMID:21218133

  20. Dual-channel phase-contrast spectral optical coherence tomography for simultaneously measuring axial and normal to B-scan off-axial displacements

    Science.gov (United States)

    Dong, Bo; Zhang, Yun; Ye, Shuangli; Zhou, Yanzhou; He, Zhaoshui; Xie, Shengli

    2017-09-01

    A dual-channel phase-contrast spectral optical coherence tomography (DPC-SOCT) method is proposed for measuring axial and normal to B-scan off-axial displacements inside weakly scattering translucent materials. By employing a dual-channel observation structure with depth multiplexing, only one shot before and one shot after the object deformation are required for simultaneously measuring the displacements. To validate the method, a DPC-SOCT system was built and axial and normal to B-scan off-axial displacements inside polymer films were measured at 20 frames per second. The results suggest that the method can be used for investigating inner mechanical properties of materials under different loads. In the future, a method for all orthogonal measurement of displacement components will be developed.

  1. Tomografia computadorizada do tórax de cadelas portadoras de neoplasias mamárias malignas: I - determinação da técnica do exame

    Directory of Open Access Journals (Sweden)

    Ana Carolina Brandão de Campos Fonseca Pinto

    2006-02-01

    Full Text Available Visto a importância das neoplasias mamárias malignas na clínica médico-veterinária e as novas perspectivas do diagnóstico por imagem na avaliação de pacientes portadores dessas neoplasias, o presente trabalho visou analisar alguns aspectos técnicos relativos ao exame de tomografia computadorizada contrastada da cavidade torácica quais sejam, tempo de realização do exame, escolha da espessura dos cortes transversais, qualidade de contrastação dos vasos mediastinais, abertura de janela e nível para obtenção das imagens de pulmão, mediastino e arcabouço ósseo, tendo em vista a escassez de informações na literatura consultada. Para tanto, foram realizados exames de tomografia computadorizada contrastada da cavidade torácica de vinte fêmeas da espécie canina, de diferentes raças e idades, portadoras de neoplasias mamárias malignas encaminhadas ao Serviço de Diagnóstico por Imagem do Hospital Veterinário da Faculdade de Medicina Veterinária e Zootecnia da Universidade de São Paulo pelos Serviços de Obstetrícia e Ginecologia e de Cirurgia de Pequenos Animais da mesma instituição. Concluiu-se que, o tempo médio para realização da tomografia contrastada completa do tórax, com aproximadamente trinta cortes foi de 30 minutos; o posicionamento em decúbito esternal com os membros tracionados cranialmente, e a administração de contraste iodado hidrossolúvel por via intravenosa no volume aproximado de 2ml/kg de peso vivo, sendo dois terços da dose administrados em bolo e o complemento sob infusão contínua mostraram-se adequados para realização do exame tomográfico contrastado do tórax; a escolha da espessura dos cortes de 10 milímetros para animais com mais de trinta quilos e de 5 milímetros para animais com menos de trinta quilos mostrou-se adequada para avaliação de todo o tórax buscando-se atingir uma média de trinta cortes; as seleções de janela e nível para aquisição das imagens pulmonares

  2. Proposta para padronização do relatório de tomografia computadorizada nos aneurismas da aorta abdominal A proposal for standardizing computed tomography reports on abdominal aortic aneurysms

    Directory of Open Access Journals (Sweden)

    Fabiola Goda Torlai

    2006-08-01

    Full Text Available OBJETIVO: Propor um modelo de padronização de relatório para aneurisma da aorta abdominal na tomografia computadorizada. MATERIAIS E MÉTODOS: Foram realizadas, no período de abril a outubro de 2004, entrevistas com integrantes da Disciplina de Cirurgia Vascular da nossa instituição, para elaboração de um modelo de padronização de relatório de tomografia computadorizada para o estudo do aneurisma da aorta abdominal. A partir deste modelo foi elaborado um questionário, enviado a nove outros cirurgiões, todos com experiência em cirurgia da aorta abdominal. O índice de resposta aos questionários foi de 55,5% (5/9. RESULTADOS: Os parâmetros de interesse citados mais freqüentemente para a avaliação dos aneurismas de aorta abdominal foram: diâmetro máximo do colo proximal, extensão do colo proximal até a artéria renal mais baixa, forma do colo proximal, diâmetro máximo do aneurisma e diâmetro das artérias ilíacas comuns. Estes dados permitiram elaborar uma proposta de modelo para padronização de relatório na tomografia computadorizada. CONCLUSÃO: Um modelo para a análise tomográfica padronizada do aneurisma de aorta abdominal permite atender às necessidades dos cirurgiões vasculares para acompanhar a evolução e planejar o tratamento destes pacientes.OBJECTIVE: To propose a model to standardize computed tomography reports on abdominal aortic aneurysms. MATERIALS AND METHODS: Interviews were carried out with members of Vascular Surgery Division of our institution, in the period between April and October 2004, aiming at developing a standardized model of computed tomography reports on abdominal aortic aneurysms. Based on this model, a questionnaire was elaborated and sent to other nine surgeons, all of them experienced in the field of abdominal aortic surgery. The questionnaires response rate was 55.5% (5/9. RESULTS: The most frequently mentioned parameters of interest for evaluation of abdominal aortic aneurysms

  3. Fibrose maciça progressiva em trabalhadores expostos à sílica: achados na tomografia computadorizada de alta resolução Progressive massive fibrosis in silica-exposed workers: high-resolution computed tomography findings

    Directory of Open Access Journals (Sweden)

    Ângela Santos Ferreira

    2006-12-01

    Full Text Available OBJETIVO: Avaliar as características radiológicas das massas conglomeradas pela tomografia computadorizada de alta resolução de tórax. MÉTODOS: Foram selecionados 75 pacientes silicóticos, a maioria jateadores de areia, portadores de fibrose maciça progressiva, atendidos no Hospital Universitário Antônio Pedro entre 1986 e 2004. Os pacientes foram submetidos a avaliação clínica, radiografia simples de tórax e tomografia computadorizada de alta resolução. RESULTADOS: Mais da metade dos pacientes com silicose complicada mostrou na radiografia de tórax grandes opacidades dos tipos B e C, denotando a gravidade da doença nesses pacientes. Dos 75 casos, apenas um apresentou massa unilateral simulando câncer de pulmão. Quarenta e quatro pacientes realizaram tomografia computadorizada de alta resolução do tórax. As massas predominaram nos terços superiores e posteriores (88,6%. Broncograma aéreo e calcificações no interior das massas foram observados em 70,4% e 63,8% dos casos, respectivamente. História de tuberculose foi relatada em 52% dos pacientes estudados. CONCLUSÃO: Na grande maioria dos casos as massas eram bilaterais, predominando nas regiões póstero-superiores dos pulmões, com broncogramas aéreos e calcificações de permeio. Associação com calcificações linfonodais foi um achado freqüente. A exposição a elevadas concentrações de poeira e a tuberculose foram consideradas fatores de risco para o desenvolvimento da fibrose maciça progressiva.OBJECTIVE: To evaluate the radiological characteristics of conglomerate masses using high-resolution computed tomography of the chest. METHODS: From among the patients treated between 1986 and 2004 at the Antonio Pedro University Hospital, 75 patients with silicosis and massive fibrosis, most working in the field of sandblasting, were selected for study. These patients were submitted to a clinical evaluation, chest X-ray and high-resolution computed tomography of

  4. Estudo comparativo do diagnóstico de câncer pulmonar entre tomografia computadorizada e broncoscopia Comparative study between computed tomography and bronchoscopy in the diagnosis of lung cancer

    Directory of Open Access Journals (Sweden)

    Christopher Oliveira

    2010-08-01

    Full Text Available OBJETIVO: Analisar a tomografia computadorizada e a broncoscopia no diagnóstico do câncer pulmonar e verificar a eficácia destas técnicas perante a presença desta doença. Os parâmetros idade, gênero, hábitos tabágicos, tipos histológicos, estadiamento e terapêutica foram, igualmente, analisados. MATERIAIS E MÉTODOS: Foram analisados 70 pacientes do Serviço de Pneumologia do Hospital Distrital da Figueira da Foz, Coimbra, Portugal, que realizaram ambas as técnicas em estudo, tendo-se confirmado ou não a presença de câncer pulmonar. RESULTADOS: Diagnosticaram-se 37 tumores pulmonares, 23 casos no gênero masculino e 14 no feminino. Histologicamente, 40,54% eram adenocarcinomas, seguido do carcinoma escamoso (32,43% dos casos e do carcinoma de pequenas células (18,92%. O estadiamento mostrou 6,70% no estádio IB, 23,30% no estádio IIIA comparativamente ao IIIB com 36,70%, encontrando-se 33,30% dos doentes no estádio IV. A quimioterapia isolada foi efetuada em 75,7% dos doentes. A sensibilidade da broncoscopia foi de 83,8%, a especificidade, de 81,8%, e a precisão, de 82,8%. A sensibilidade da tomografia computadorizada foi de 81,1%, a especificidade, de 63,6%, e a precisão, de 72,8%. CONCLUSÃO: Os resultados da broncoscopia confirmaram a sua importância no diagnóstico do câncer pulmonar, pela dependência deste no exame anatomopatológico do tecido ou células, obtido por várias técnicas de biópsia. A tomografia computadorizada apresentou boa sensibilidade, de 81,1%, contudo, a sua especificidade, de apenas 63,6%, resulta do número de falso-positivos (36,4%.OBJECTIVE: To analyze the role of computed tomography and bronchoscopy in the diagnosis of lung cancer, evaluating the effectiveness of these techniques in the presence of this disease. Parameters such as age, gender, smoking habits, histological types, staging and treatment were also analyzed. MATERIALS AND METHODS: The sample of the present study included 70

  5. Análise de carcinomas epidermóides por meio de radiografia panorâmica e tomografia computadorizada Analysis of squamous cell carcinomas by means of panoramic radiography and computed tomography

    Directory of Open Access Journals (Sweden)

    Amanda Cáceres PEREIRA

    2001-12-01

    Full Text Available Este trabalho teve como objetivo correlacionar aspectos radiográficos como, localização e extensão do tumor, infiltração óssea e de tecidos moles e destruição das corticais, obtidos nas radiografias panorâmicas com os encontrados nas tomografias computadorizadas (TCs. Os aspectos radiográficos de 48 pacientes com diagnóstico histopatológico de carcinomas epidermóides, localizados em várias regiões do complexo buco-maxilo-facial, foram analisados por 4 radiologistas. As radiografias panorâmicas e as tomografias computadorizadas foram realizadas nos hospitais e clínicas da Universidade de Iowa (EUA, FUNDECTO - USP e Hospital Universitário da Universidade de São Paulo (SP, Brasil. Como resultados, obtivemos a grande limitação da radiografia panorâmica em determinar a localização e extensão do tumor, com delimitações bastante imprecisas da lesão. Já as TCs ofereceram resultados mais direcionados como: invasão do tumor em direção a estruturas moles adjacentes, extensão da destruição óssea, bem como a profundidade da lesão, que foram confirmados com os achados cirúrgicos. Concluímos que a tomografia computadorizada demonstrou ser uma técnica bastante sensível na detecção do comprometimento ósseo e do envolvimento de tecidos moles, proporcionando, assim, o auxílio no diagnóstico e no planejamento do tratamento. No entanto, a radiografia panorâmica foi muito pouco sensível e eficaz, por mostrar apenas margens imprecisas e pouco nítidas da lesão, não avaliando o envolvimento de tecidos moles.The purpose of this work was to compare radiographic findings, such as localization and extension of tumors toward the bone and soft tissues, in panoramic radiography and computed tomography (CT. Four radiologists assessed the radiographic findings of 48 patients with the histopathological diagnosis of squamous cell carcinoma in different sites of the maxillofacial region. Panoramic radiographs and computed

  6. Method of evaluation of diagnostics reference levels in computerized tomography; Metodo de avaliacao de niveis de referencia de radiodiagnostico em tomografia computadorizada

    Energy Technology Data Exchange (ETDEWEB)

    Vega, Walter Flores

    1999-04-01

    Computerized tomography is a complex technique with several selectable exposition parameters delivering high doses to the patient. In this work it was developed a simple methodology to evaluate diagnostic reference levels in computerized tomography, using the concept of Multiple Scan Average Dose (MSAD), recently adopted by the Health Ministry. For evaluation of the MSAD, a dose distribution was obtained through a measured dose profile on the axial axis of a water phantom with thermoluminescence dosemeters, TLD-100, for different exam technique. The MSAD was evaluated hrough two distinct methods. First, it was evaluated by the integration of the dose profile of a single slice and, second, obtained by the integration on central slice of the profile of several slices. The latter is in of accordance with the ionization chamber method, suggesting to be the most practical method of dose evaluation to be applied in the diagnostic reference level assessment routine for CT, using TLDs. (author)

  7. Quando a fase de equilíbrio pode ser suprimida nos exames de tomografia computadorizada de abdome? What is the real role of the equilibrium phase in abdominal computed tomography?

    Directory of Open Access Journals (Sweden)

    Priscila Silveira Salvadori

    2013-04-01

    Full Text Available OBJETIVO: Avaliar a necessidade de realização da fase de equilíbrio nos exames de tomografia computadorizada de abdome. MATERIAIS E MÉTODOS: Realizou-se estudo retrospectivo, transversal e observacional, avaliando 219 exames consecutivos de tomografia computadorizada de abdome com contraste intravenoso, realizados num período de três meses, com diversas indicações clínicas. Para cada exame foram emitidos dois pareceres, um avaliando o exame sem a fase de equilíbrio (primeira análise e o outro avaliando todas as fases em conjunto (segunda análise. Ao final de cada avaliação, foi estabelecido se houve mudança nos diagnósticos principais e secundários, entre a primeira e a segunda análise. Foi utilizada a extensão do teste exato de Fisher para avaliar a modificação dos diagnósticos principais (p 0,999. Com relação aos diagnósticos secundários, cinco exames (2,3% foram modificados. CONCLUSÃO: Para indicações clínicas como estadiamento tumoral, abdome agudo e pesquisa de coleção abdominal, a fase de equilíbrio não acrescenta contribuição diagnóstica expressiva, podendo ser suprimida dos protocolos de exame.OBJECTIVE: To evaluate the role of the equilibrium phase in abdominal computed tomography. MATERIALS AND METHODS: A retrospective, cross-sectional, observational study reviewed 219 consecutive contrast-enhanced abdominal computed tomography images acquired in a three-month period, for different clinical indications. For each study, two reports were issued - one based on the initial analysis of non-contrast-enhanced, arterial and portal phases only (first analysis, and a second reading of these phases added to the equilibrium phase (second analysis. At the end of both readings, differences between primary and secondary diagnoses were pointed out and recorded, in order to measure the impact of suppressing the equilibrium phase on the clinical outcome for each of the patients. The extension of the exact Fisher

  8. Tomografia computadorizada de feixe cônico na odontologia veterinária: descrição e padronização da técnica

    Directory of Open Access Journals (Sweden)

    Marcello R. Roza

    2009-08-01

    Full Text Available Onze cães e quatro gatos, portadores de alterações buco-dentárias e atendidos no Centro Veterinário do Gama, em Brasília, DF, foram submetidos à tomografia computadorizada de feixe cônico. Os exames foram realizados em um tomógrafo i-CAT, utilizando para aquisição das imagens, altura de seis centímetros, tempo de 40 segundos, 0,2 voxel, 120 kilovolts e 46,72 miliampéres por segundo. O melhor posicionamento dos animais para realização do exame foi definido neste estudo. Esse é um fator fundamental para a realização do exame, que necessitou um protocolo anestésico simples e seguro, em função do tempo mínimo necessário à obtenção das imagens. Várias alterações e enfermidades foram identificadas, com extrema acurácia, credenciando a tomografia computadorizada de feixe cônico como um exame seguro, acessível e exeqüível e que pode ser incorporado à rotina odontológica das clínicas de pequenos animais.Eleven dogs and four cats with buccodental alterations, treated in the Centro Veterinário do Gama, in Brasilia, DF, Brazil, were submitted to cone beam computed tomography. The exams were carried out in a i-CAT tomograph, using for image acquisition six centimeters height, 40 seconds time, 0.2 voxel, 120 kilovolts and 46.72 milliamperes per second. The ideal positioning of the animal for the exam was also determined in this study and it proved to be fundamental for successful examination, which required a simple and safe anesthetic protocol due to the relatively short period of time necessary to obtain the images. Several alterations and diseases were identified with accurate imaging, demonstrating that cone beam computed tomography is a safe, accessible and feasible imaging method which could be included in the small animal dentistry routine diagnosis.

  9. Comparação morfométrica da orelha interna entre ovinos e humanos através da tomografia computadorizada CT-Scan sheep and human inner ear morphometric comparison

    Directory of Open Access Journals (Sweden)

    Valter Ayres Seibel

    2006-06-01

    Full Text Available INTRODUÇÃO: trabalhos sobre o uso de ovelhas em cirurgias experimentais e treinamento em cirurgia otológica são raros. Este estudo pretende contribuir para ampliar o conhecimento nessa área. OBJETIVO: Estudar a orelha interna da ovelha por meio de tomografia computadorizada e cortes sucessivos com o intuito de apresentar dados morfométricos mais precisos relacionados à comparação entre a orelha de ovelhas e a de humanos. MATERIAL E MÉTODO: Foi realizado um estudo descritivo sem seguimento no qual foram comparadas as estruturas da orelha interna da ovelha com as dos humanos. As medidas foram obtidas através de tomografias computadorizadas e avaliadas por meio de um programa de análise de imagens médicas (Osíris 4.16. RESULTADOS: O estudo morfológico da orelha da ovelha, em média, e da orelha humana, em média, revelaram grande similaridade de anatomia. A maior parte das estruturas (10 de 15 preservou a relação proposta de 2/3 da dimensão humana em relação à dimensão ovina. CONCLUSÃO: Os achados contribuem para uso da orelha da ovelha como modelo em cirurgia experimental e treinamento em cirurgia otológica.INTRODUCTION: Studies about the use of sheep in surgical training and experimental otologic surgery are rare. This study intends to contribute to the knowledge on this field. AIM: To study sheep inner ear structures using computerized tomography and serial cross-sections to collect more accurate morphometric data to compare sheep and human ears. MATERIAL AND METHODS: This descriptive study compared the inner structures of sheep and human ears. Measurements were made using computerized tomography, and they were stored in a DICOM compact disc for later analysis and manipulation, with a program used for medical image analysis (Osíris 4.16. RESULTS: Mean measures for sheep and human ears were found to be similar in this morphological study. Most structures (10 out of 15 maintained the 2/3 ratio of sheep to human ear

  10. An electrostatic lower stator axial-gap polysilicon wobble motor part I: Design and modeling

    NARCIS (Netherlands)

    Legtenberg, R.; Legtenberg, Rob; Berenschot, Johan W.; van Baar, J.J.J.; Elwenspoek, Michael Curt

    This paper presents design issues and a theoretical model of electrostatically driven axial-gap polysilicon wobble motors. The motor design benefits from large axial rotor-to-stator overlap and large gear ratios, and motor designs with rotor radii of 50 and 100 μm are capable of generating torques

  11. SCP2, a major protein component of the axial elements of synaptonemal complexes

    NARCIS (Netherlands)

    Schalk, J.A.C.

    1999-01-01

    Synaptonemal complexes (SCs) are ladderlike protein structures, which are formed between homologous chromosomes during the prophase of the first meiotic division. SCs consist of two axial elements, one along each chromosome, and transverse filaments (TFs), which connect the axial elements.

  12. Lungfish axial muscle function and the vertebrate water to land transition.

    Directory of Open Access Journals (Sweden)

    Angela M Horner

    Full Text Available The role of axial form and function during the vertebrate water to land transition is poorly understood, in part because patterns of axial movement lack morphological correlates. The few studies available from elongate, semi-aquatic vertebrates suggest that moving on land may be powered simply from modifications of generalized swimming axial motor patterns and kinematics. Lungfish are an ideal group to study the role of axial function in terrestrial locomotion as they are the sister taxon to tetrapods and regularly move on land. Here we use electromyography and high-speed video to test whether lungfish moving on land use axial muscles similar to undulatory swimming or demonstrate novelty. We compared terrestrial lungfish data to data from lungfish swimming in different viscosities as well as to salamander locomotion. The terrestrial locomotion of lungfish involved substantial activity in the trunk muscles but almost no tail activity. Unlike other elongate vertebrates, lungfish moved on land with a standing wave pattern of axial muscle activity that closely resembled the pattern observed in terrestrially locomoting salamanders. The similarity in axial motor pattern in salamanders and lungfish suggests that some aspects of neuromuscular control for the axial movements involved in terrestrial locomotion were present before derived appendicular structures.

  13. Concept design of the axial injection system of type CYCIAE cyclotrons

    International Nuclear Information System (INIS)

    Xiao Meiqin; Zhang Tianjue; Fan Mingwu

    1996-01-01

    Beam optics properties of the axial injection system of CYCIAE30 is calculated and compared with operation results to show that the theory and the calculation method used are reasonable. Then, the concept design of the axial injection system of CYCIAE 70 is made and optimization results are obtained

  14. Passive axial magnetic bearing with Halbach magnetized array in magnetically suspended control moment gyro application

    International Nuclear Information System (INIS)

    Sun Jinji; Ren Yuan; Fang Jiancheng

    2011-01-01

    The paper presents a special configuration of passive axial magnetic bearing with segmented Halbach magnetized array in magnetically suspended control moment gyro (MSCMG). Peculiarity of presented passive axial magnetic bearing is its ability to provide angular stiffness so that it can produce gyro moment when it is used in MSCMG. The MSCMG with this passive axial magnetic bearing can efficiently reduce the power loss when it supplies gyro moment compared with the five degrees of freedom (5-DOF) MSCMG. The characteristics of the suspension force and stiffness of the passive axial magnetic bearing are studied using finite element method (FEM). The performance of the presented passive axial magnetic bearing with Halbach magnetized array is verified by a prototyped MSCMG. - Research highlights: → Passive axial magnetic bearing is used to provide angular stiffness. → Passive axial magnetic bearing is based on repulsion. → Layers Halbach magnetized array realizes higher stiffness per bearing volume. → Passive axial magnetic bearing can provide gyro moment in CMG. → Power loss of MSCMG with PMB does not increase when it provides gyro moment.

  15. Indigenous development of a 2 kW RF-excited fast axial flow CO2 ...

    Indian Academy of Sciences (India)

    RF-excited fast axial flow CO2 lasers in kilowatt regime are presently being used for various new scientific applications in addition to laser material processing because of its versatility and superior beam quality. We have indigenously developed a compact 2 kW RF-excited fast axial flow CO2 laser with moderate beam ...

  16. A benchmark study of procedures for analysis of axial crushing of bulbous bows

    DEFF Research Database (Denmark)

    Yamada, Yasuhira; Pedersen, Preben Terndrup

    2008-01-01

    Simplified methods to estimate mean axial crushing forces of plated structures are reviewed and applied to a series of experimental results for axial crushing of large-scale bulbous bow models. Methods based on intersection unit elements such as L-, T- and X-type elements as well as methods based...

  17. Clinical evaluation of internal axial wall divergence in inlays and casting post-and-core fabrication

    Directory of Open Access Journals (Sweden)

    Min-Chieh Hsieh

    2015-06-01

    Conclusion: Compared with the teeth preparation of external axial wall in a single crown, the sighted distance at 30-cm distance in the internal axial wall is 1.5 × wider. More sighted distances are required to prevent undesired undercuts.

  18. Constraining vectors and axial-vectors in walking technicolour by a holographic principle

    DEFF Research Database (Denmark)

    D. Dietrich, Dennis; Kouvaris, Christoforos

    2008-01-01

    We use a holographic principle to study the low-energy spectrum of walking technicolour models. In particular, we predict the masses of the axial vectors as well as the decay constants of vectors and axial vectors as functions of the mass of the techni-rho. Given that there are very few...

  19. Cdx and Hox Genes Differentially Regulate Posterior Axial Growth in Mammalian Embryos

    NARCIS (Netherlands)

    Young, Teddy; Rowland, Jennifer Elizabeth; van de Ven, Cesca; Bialecka, Monika; Novoa, Ana; Carapuco, Marta; van Nes, Johan; de Graaff, Wim; Duluc, Isabelle; Freund, Jean-Noel; Beck, Felix; Mallo, Moises; Deschamps, Jacqueline

    2009-01-01

    Hox and Cdx transcription factors regulate embryonic positional identities. Cdx mutant mice display posterior body truncations of the axial skeleton, neuraxis, and caudal urorectal structures. We show that trunk Hox genes stimulate axial extension, as they can largely rescue these Cdx mutant

  20. Osteoblastomas of the axial skeleton shown by skeletal scanning: case report

    International Nuclear Information System (INIS)

    Martin, N.L.; Preston, D.F.; Robinson, R.G.

    1976-01-01

    Two patients with osteoblastoma of the axial skeleton showed intense uptake of 99 /sup m/Tc-polyphosphate and 99 /sup m/Tc-diphosphonate on skeletal scans. Although this lesion is uncommon, it should be included in the differential diagnosis for young patients who show abnormal accumulation of 99 /sup m/Tc-phosphates in the axial skeleton