Visualizing the ac magnetic susceptibility of superconducting films via magneto-optical imaging

We have established a link between the global ac response and the local flux distribution of superconducting films by combining magnetic ac susceptibility, dc magnetization, and magneto-optical measurements. The investigated samples are three Nb films: a plain specimen, used as a reference sample, and other two films patterned with square arrays of antidots. At low temperatures and small ac amplitudes of the excitation field, the Meissner screening prevents penetration of flux into the sample. Above a certain ac drive threshold, flux avalanches are triggered during the first cycle of the ac excitation. The subsequent periodic removal, inversion, and rise of flux occurs essentially through the already-created dendrites, giving rise to an ac susceptibility signal weakly dependent on the applied field. The intradendrite flux oscillation is followed, at higher values of the excitation field, by a more drastic process consisting of creation of new dendrites and antidendrites. In this more invasive regime, the ac susceptibility shows a clear field dependence. At higher temperatures a smooth penetration occurs, and the flux profile is characteristic of a critical state. We have also shown that the regime dominated by vortex avalanches can be reliably identified by ac susceptibility measurements. © 2011 American Physical Society.

Stress analysis in oral obturator prostheses: Imaging photoelastic

Maxillary defects resulting from cancer, trauma, and congenital malformation affect the chewing efficiency and retention of dentures in these patients. The use of implant-retained palatal obturator dentures has improved the self-esteem and quality of life of several subjects. We evaluate the stress distribution of implant-retained palatal obturator dentures with different attachment systems by using the photoelastic analysis images. Two photoelastic models of the maxilla with oral-sinus-nasal communication were fabricated. One model received three implants on the left side of the alveolar ridge (incisive, canine, and first molar regions) and the other did not receive implants. Afterwards, a conventional palatal obturator denture (control) and two implant-retained palatal obturator dentures with different attachment systems (O-ring; bar-clip) were constructed. Models were placed in a circular polariscope and a 100-N axial load was applied in three different regions (incisive, canine, and first molar regions) by using a universal testing machine. The results were photographed and analyzed qualitatively using a software (Adobe Photoshop). The bar-clip system exhibited the highest stress concentration followed by the O-ring system and conventional denture (control). Images generated by the photoelastic method help in the oral rehabilitator planning. © 2013 SPIE.

Lamb mode diversity imaging for non-destructive testing of plate-like structures

Several Lamb wave modes can be coupled to a particular structure, depending on its geometry and transducer used to generate the guided waves. Each Lamb mode interacts in a particular form with different types of defects, like notches, delamination, surface defects, resulting in different information which can be used to improve damage detection and characterization. An image compounding technique that uses the information obtained from different propagation modes of Lamb waves for non-destructive testing of plate-like structures is proposed. A linear array consisting of 16 piezoelectric elements is attached to a 1 mm thickness aluminum plate, coupling the fundamental A0 and S0 modes at the frequencies of 100 kHz and 360 kHz, respectively. For each mode two images are obtained from amplitude and phase information: one image using the Total Focusing Method (TFM) and one phase image obtained from the Sign Coherence Factor (SCF). Each TFM image is multiplied by the SCF image of the respective mode to improve contrast and reduce side and grating lobes effects. The high dispersive characteristic of the A0 mode is compensated for adequate defect detection. The information in the SCF images is used to select one of the TFM mode images, at each pixel, to obtain the compounded image. As a result, dead zone is reduced, resolution and contrast are improved, enhancing damage detection when compared to the use of only one mode. © 2013 Elsevier Ltd.

Pesquisa de segunda neoplasia em boca e orofaringe em pacientes portadores de carcinoma espinocelular (CEC) de esôfago, boca e orofaringe através de narrow band imaging (NBI)

Pós-graduação em Pesquisa e Desenvolvimento (Biotecnologia Médica) - FMB

CRS seismic data imaging system: a case study for basib reevaluation

Este trabalho apresenta resultados práticos de uma atenção sistemática dada ao processamento e à interpretação sísmica de algumas linhas terrestres do conjunto de dados do gráben do Tacutu (Brasil), sobre os quais foram aplicadas etapas fundamentais do sistema WIT de imageamento do empilhamento CRS (Superfície de Reflexão Comum) vinculado a dados. Como resultado, esperamos estabelecer um fluxograma para a reavaliação sísmica de bacias sedimentares. Fundamentado nos atributos de frente de onda resultantes do empilhamento CRS, um macro-modelo suave de velocidades foi obtido através de inversão tomográfica. Usando este macro-modelo, foi realizado uma migração à profundidade pré- e pós-empilhamento. Além disso, outras técnicas baseadas no empilhamento CRS foram realizadas em paralelo como correção estática residual e migração de abertura-limitada baseada na zona de Fresnel projetada. Uma interpretação geológica sobre as seções empilhadas e migradas foi esboçada. A partir dos detalhes visuais dos painéis é possível interpretar desconformidades, afinamentos, um anticlinal principal falhado com conjuntos de horstes e grábens. Também, uma parte da linha selecionada precisa de processamento mais detalhado para evidenciar melhor qualquer estrutura presente na subsuperfície.

Estudo comparativo de dois programas de computador (Dolphin Imaging e Nemotec) versus o método manual utilizados para análises cefalométricas de pacientes com deformidade dento-facial padrão II

A-Nperp, Pg-Nperp e mandibular plane). Thirty patients (male or female), with age varying from 19 to 48 years old were analyzed. All patients were diagnosted with mandibular retrognathism and submitted to bilateral sagital mandibular advancement. All tracings were performed in lateral cephalometric radiographs obtained one week before surgery. The intraclass correlation coefficient analysis (ICC), the t test adjusted for Tukey-Kramer test and Schuirmann test were applied. The results showed that the manual tracings and Nemotec® tracing had excellent reliabilities for all measures (ICC > 0.98). The Dolphin Imaging® showed low reliability in anterior facial height (value of ICC = 0.70), Co-A (value of ICC = 0.47) and Co-Gn (ICC value = 0.49). In A-Nperp, Pg-Nperp, Mandibular plan, SNA and SNB there were no differences between the 3 tracings (p > 0.05), for the anterior facial height measures differences were found between the Dolphin Imaging® and Nemotec® tracings, but no differences were observed as compared to the manual tracing (p > 0.05), in Co-A and Co-Gn measures t Dolphin Imaging® presented a significantly lower mean than the other methods (p > 0.05). The manual tracings were equivalent in 6 of 8 measures (A-Nperp, Pg-Nperp, md Plan, SNA, SNB and Co-A), there was no equivalence between the methods in the anterior facial height and Co-Gn measures (p < 0.01). The Dolphin Imaging® method was not equivalent in any of the 8 measures. It was concluded that in the manual tracing only the Co- Gn, Pg-Nperp and SNB measures confirmed the diagnosis of mandibular retrognathism, and the Nemotec® software showed better results than the Dolphin Imaging® software.

Stress analysis in oral obturator prostheses over parallel and tilted implants: photoelastic imaging

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

MALDI Imaging Analysis of Neuropeptides in the Africanized Honeybee (Apis mellifera) Brain: Effect of Ontogeny

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Stress analysis in oral obturator prostheses, part II: photoelastic imaging

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Tomographic imaging of lunulae in capybara knees

The lunulae, ossification of the meniscus, are found in several species of rodents. Some studies suggest that the lunulae may be anatomical features, because there are not any pathological findings in microscopy. The objective of this study was to investigate the presence of lunulae in capybara knees, the world's largest rodent, by simple tomographic scans and three-dimensional reconstruction. For this purpose, we used two adult capybaras, in which both knees were evaluated. The lunulae were visualized with three-dimensional images, and revealed a total of two cranially. With the presence of lunulae confirmed, the capybara may be included in the group of rodents that have this structural feature, which can also contribute to the distinction between pathological processes and normal anatomic structures on imaging tests.

Retrospective study of 32 encephalic tumors diagnosed by advanced - image magnetic resonance imaging and computed tomography

The incidence of encephalic tumors in dogs and cats has increased in recent years due to the constant advancement of methods of specialist Diagnostic Imaging: Magnetic Resonance Imaging (MRI) and Computed Tomography (CT), used in small animals. These tools, which were distant in the past, are now becoming increasingly important as an additional aid to the identification of tumor processes in the Central Nervous System. The objective, of the present study, was describe imaging findings obtained in 32 cases of encephalic tumors, through techniques of CT and MR imaging procedures during the years 2004 to 2011. Were diagnosed 19/32 by MRI and 13/32 by CT, being the most affected breed Boxer (9/32), the mean age was 10 years.

Usefulness of computed tomography and magnetic resonance imaging in radiotherapy planning for the treatment of brain tumors

Advanced diagnostic techniques such as magnetic resonance imaging and computed tomography have become useful tools for confirmation of presumptive diagnosis of structural lesions in the brain such as encephalic neoplasms in small animal veterinary practice in Colombia, allowing an effective treatment planning that is more specific and less invasive for this type of pathology.

Desenvolvimento da técnica de MALDI Imaging utilizando tecidos animais

Currently the study of important molecular compounds present in low abundance in some tissues has been a challenge for proteomic analysis classic. An analysis requires more exploratory investigation of small regions of a tissue or a group of cells. MALDI Imaging Technology (MSI) is an application of mass spectrometry facing the chemical analysis of intact tissues. Thus, advances in mass spectrometry MALDI being obtained by the integration of histology, the best methods and automation are the main tools of data analysis. This tool has become essential to analyze the spatial distribution of peptides and proteins throughout the tissue sections, providing an enormous amount of data with minimum sample preparation. Thus, the aim of this study was to develop the technique of MALDI Imaging using tissue from glioblastoma multiforme (GBM), a form of most common malignant tumor in the brain. For this we used the printer chemical ChIP-1000 (Chemical Inkjet Printer, Shimadzu) and mass spectrometer type Maldi-ToF-ToF (Axima Performance, Shimadzu), a search of the identifications were performed in databases such as SwissProt. We identified more than forty proteins with diverse functions such as proteins F-actin-capping and Thymosin to the structure and organization cellular and proteins such several Tumor necrosis factor receptor development-related pathology. The development of this technique will permit to carry-out proteomic analysis directly into the tissue, enabling earlier diagnosis of diseases, as well as the identification and characterization of potential biomarkers of disease.