2013
Authors
Pereira, T; Vaz, P; Oliveira, T; Santos, I; Pereira, HC; Almeida, V; Correia, C; Cardoso, J;
Publication
PHYSIOLOGICAL MEASUREMENT
Abstract
A new type of optical probe based on laser Doppler self-mixing technology, for a truly non-contact measurement in a single location, and extraction of the temporal features of the distension wave in the arterial wall, was developed. The monitoring of temporal features allows the assessment of cardiovascular function when measurement is carried out at the carotid artery. An algorithm based on the short-time Fourier transform and empirical mode decomposition was applied to the test setup self-mixing signals for the determination of waveform features, with an accuracy of a few milliseconds and a root mean square error less than 3 ms. In vivo testing signals show great consistency in the measured pulse pressure waveform.
2013
Authors
Petry, MR; Moreira, AP; Faria, BM; Reis, LP;
Publication
2013 IEEE 15th International Conference on e-Health Networking, Applications and Services, Healthcom 2013
Abstract
Intelligent wheelchairs can become an important solution to assist physically impaired individuals who find it difficult or impossible to drive regular powered wheelchairs. However, when designing the hardware architecture several projects compromise the user comfort and the wheelchair normal usability in order to solve robotic problems. In this paper we describe the main concepts regarding the design of the IntellWheels intelligent wheelchair. Our approach has a user-centered perspective, in which the needs and limitations of physically impaired users are given extensive attention at each stage of the design process. Finally, our design was evaluated through a public opinion assessment. A statistical analysis suggested that the design was effective to mitigate the visual and ergonomic impacts caused by the addition of sensorial and processing capabilities on the wheelchair. © 2013 IEEE.
2013
Authors
Silva Cunha, JPS; Remi, J; Vollmar, C; Fernandes, JM; Gonzalez Victores, JA; Noachtar, S;
Publication
EPILEPSY & BEHAVIOR
Abstract
We quantitatively evaluated the localizing and lateralizing characteristics of ictal upper limb automatisms (ULAs) in patients with temporal lobe epilepsy (TLE; n = 38) and frontal lobe epilepsy (FLE; n = 20). Movement speed, extent, length, and duration of ULAs were quantitatively analyzed with motion capturing techniques. Upper limb automatisms had a larger extent (p < 0.001), covered more distance (p < 0.05), and were faster (p < 0.001) in FLE than in TLE. In TLE, the maximum speed of ULAs was higher ipsilaterally than contralaterally (173 vs. 84 pixels/s; p = 0.02), with no significant difference in FLE (511 vs. 428). The duration of ictal automatisms in relation to the total seizure duration was shorter in TLE than in FLE (median 36% vs. 63%; p < 0.001), with no difference in the absolute duration (26 s vs. 27 s). These results demonstrate that quantitative movement analysis of ULAs differentiates FLE from TLE, which may aid in the localization of the epileptogenic zone.
2013
Authors
Oliveira, L; Carvalho, MI; Nogueira, E; Tuchin, VV;
Publication
JOURNAL OF INNOVATIVE OPTICAL HEALTH SCIENCES
Abstract
With the objective to study the variation of optical properties of rat muscle during optical clearing, we have performed a set of optical measurements from that kind of tissue. The measurements performed were total transmittance, collimated transmittance, specular reflectance and total reflectance. This set of measurements is sufficient to determine diffuse reflectance and absorbance of the sample, also necessary to estimate the optical properties. All the performed measurements and calculated quantities will be used later in inverse Monte Carlo (IMC) simulations to determine the evolution of the optical properties of muscle during treatments with ethylene glycol and glucose. The results obtained with the measurements already provide some information about the optical clearing treatments applied to the muscle and translate the mechanisms of turning the tissue more transparent and sequence of regimes of optical clearing.
2013
Authors
Borges, E; Sequeira, M; Cortez, AFV; Pereira, HC; Pereira, T; Almeida, V; Vasconcelos, TM; Duarte, IM; Nazare, N; Cardoso, J; Correia, C;
Publication
BIODEVICES 2013 - Proceedings of the International Conference on Biomedical Electronics and Devices
Abstract
Electrical impedance spectroscopy, EIS, has been proving efficacy and utility in a wide range of areas, from the characterization of biological tissues to living organisms. Several commercial solutions, with high precision and resolution, are available. Nonetheless, the typical equipments are expensive, unfeasible for in vivo and in field applications and unspecific for concrete applications. These features, together with the lately demands in the vegetal field, fundament this work. Actually, the fast spread of asymptomatic forest diseases, with no cure available to date, such as the pinewood disease, PWD, constitute a problem of economical and forestall huge proportions. Herein is proposed a portable EIS system, for biological applications, able to perform AC current or voltage scans within a selectable frequency range. The procedure and the results obtained for a population of 24 young pine trees (Pinus pinaster Aiton) are also presented. Pine trees were kept in a controlled environment and were inoculated with the nematode (Bursaphelenchus xylophilus Nickle), that causes the PWD, and also with bark beetles (Tomicus destruens Wollaston). Some degree of discrimination between different physiological states was achieved. These results may constitute a first innovative approach to the diagnosis of such types of diseases.
2013
Authors
Oliveira, LM; Carvalho, MI; Nogueira, EM; Tuchin, VV;
Publication
LASER PHYSICS
Abstract
The study of agent diffusion in biological tissues is very important to understand and characterize the optical clearing effects and mechanisms involved: tissue dehydration and refractive index matching. From measurements made to study the optical clearing, it is obvious that light scattering is reduced and that the optical properties of the tissue are controlled in the process. On the other hand, optical measurements do not allow direct determination of the diffusion properties of the agent in the tissue and some calculations are necessary to estimate those properties. This fact is imposed by the occurrence of two fluxes at optical clearing: water typically directed out of and agent directed into the tissue. When the water content in the immersion solution is approximately the same as the free water content of the tissue, a balance is established for water and the agent flux dominates. To prove this concept experimentally, we have measured the collimated transmittance of skeletal muscle samples under treatment with aqueous solutions containing different concentrations of glucose. After estimating the mean diffusion time values for each of the treatments we have represented those values as a function of glucose concentration in solution. Such a representation presents a maximum diffusion time for a water content in solution equal to the tissue free water content. Such a maximum represents the real diffusion time of glucose in the muscle and with this value we could calculate the corresponding diffusion coefficient.
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