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Introduction To realize noninvasive diagnosis and early diagnosis of coronary heart disease, the study proposes a new time-frequency method for analyzing heart sound signals. This method is based on Choi-Williams Distribution (CWD). Methods CWD distribution is developed and modified from Wigner Ville distribution (WVD). To solve the problem of cross-term interference existing in WVD there is an improved version of WVD, called Choi-Williams Distribution (CWD), which introduces the smoothing window as the kernel function and deals with the time-frequency analysis of heart sound signal. Results The improved method has good performance and can be implemented simply without much increase of operation complexity. Conclusion In this paper, 21 cases of heart sound signals are acquired from the outpatients and hospitalized patients with coronary heart diseases. The research results of 21 cases show that the CWD method can be used to analyze heart sounds. It accurately identifies the 9 cases of heart sounds of health people and 12 cases of heart sounds of patients with coronary heart disease. Besides, the CWD displays obvious differences between heart sounds of healthy people and abnormal heart sounds. The contour line of heart sounds from healthy people shows the following characteristics: concise, columnar and non-divergence; while the contour line of abnormal heart sounds is divergent and has many columnar links. These research shows that CWD method can effectively distinguish heart sounds between healthy people and patients with coronary heart disease.

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Abstract Introduction This paper's aim is to develop a data warehouse from the integration of the files of three Brazilian health information systems concerned with the production of ambulatory and hospital procedures for cancer care, and cancer mortality. These systems do not have a unique patient identification, which makes their integration difficult even within a single system. Methods Data from the Brazilian Public Hospital Information System (SIH-SUS), the Oncology Module for the Outpatient Information System (APAC-ONCO) and the Mortality Information System (SIM) for the State of Rio de Janeiro, in the period from January 2000 to December 2004 were used. Each of the systems has the monthly data production compiled in dbase files (dbf). All the files pertaining to the same system were then read into a corresponding table in a MySQL Server 5.1. The SIH-SUS and APAC-ONCO tables were linked internally and with one another through record linkage methods. The APAC-ONCO table was linked to the SIM table. Afterwards a data warehouse was built using Pentaho and the MySQL database management system. Results The sensitivities and specificities of the linkage processes were above 95% and close to 100% respectively. The data warehouse provided several analytical views that are accessed through the Pentaho Schema Workbench. Conclusion This study presented a proposal for the integration of Brazilian Health Systems to support the building of data warehouses and provide information beyond those currently available with the individual systems.

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Introduction Nowadays Knee Osteoarthritis (KOA) affects a large percentage of the elderly, and one solution is to perform a Total Knee Arthroplasty (TKA). In this paper, one intends to study the gait and posture of these patients after the TKA, while walking with three assistive devices (ADs) (crutches, standard walker (SW) and rollator with forearm supports (RFS)). Methods Eleven patients were evaluated in 2 phases: 5 days and 15 days after surgery. This evaluation was conducted with two inertial sensors, one attached to the operated leg ankle, to measure spatiotemporal parameters, and the other at the sacrum, to measure posture and fall risk-related parameters. Multivariate analysis of variance (MANOVA) with repeated measures was performed to detect group differences. Results The MANOVA results show that all spatiotemporal parameters are significantly different (p<0.05) between the two phases of study. So, time has a significant influence on such parameters. In relation to the ADs, one observes that there are statistical significant effects on all spatiotemporal parameters, except for swing duration and step length (p>0.05). The interaction between time and ADs only affects significantly the velocity (p<0.05). In terms of fall risk parameters, time only significantly affects the antero-posterior direction (p<0.05) and ADs affects significantly root mean square in medio-lateral direction (p<0.05). In terms of interaction between time and ADs, there are no statistical significant differences. Conclusion This study concludes that depending on the state of recovery of the patient, different ADs should be prescribed. On the overall, standard walker is good to give stability to the patient and RFS allows the patient to present a gait pattern closer to a natural gait.

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Introduction The main idea of a traditional Steady State Visually Evoked Potentials (SSVEP)-BCI is the activation of commands through gaze control. For this purpose, the retina of the eye is excited by a stimulus at a certain frequency. Several studies have shown effects related to different kind of stimuli, frequencies, window lengths, techniques of feature extraction and even classification. So far, none of the previous studies has performed a comparison of performance of stimuli colors through LED technology. This study addresses precisely this important aspect and would be a great contribution to the topic of SSVEP-BCIs. Additionally, the performance of different colors at different frequencies and the visual comfort were evaluated in each case. Methods LEDs of four different colors (red, green, blue and yellow) flickering at four distinct frequencies (8, 11, 13 and 15 Hz) were used. Twenty subjects were distributed in two groups performing different protocols. Multivariate Synchronization Index (MSI) was the technique adopted as feature extractor. Results The accuracy was gradually enhanced with the increase of the time window. From our observations, the red color provides, in most frequencies, both highest rates of accuracy and Information Transfer Rate (ITR) for detection of SSVEP. Conclusion Although the red color has presented higher ITR, this color was turned in the less comfortable one and can even elicit epileptic responses according to the literature. For this reason, the green color is suggested as the best choice according to the proposed rules. In addition, this color has shown to be safe and accurate for an SSVEP-BCI.

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Abstract Introduction Brain Computer Interfaces provide an alternative communication path to severe paralyzed people and uses electrical signals related to brain activity in order to identify the user’s intention. In this paper a classifier based on a Self-Organizing Map is introduced. Methods Electroencephalography signal is used on this work as a source for the user’s intention. This signal represents the brain activity and is processed in order to extract the frequency features presented to the classifier, which uses a Self-Organizing Map and a series of probability masks in order to identify the correct class. Results The proposed structure was evaluated using a dataset of Electroencephalography with three mental tasks. The system was able to identify the different states of the users intention with an accuracy of 71.21% for a three-class problem using only 25 neurons for one of the users. Conclusion The classifier proposed in this paper has an accuracy that is around the value of similar works in the literature, using the same data, but using a small time window for the classification, meaning the system can have a better time response for the user.

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Introduction: Low-level laser therapy (LLLT) is effective in preventing fatigue and in stimulating the microcirculation and cellular activity. In this study, we examined the effect of LLLT on injured tibial muscle in vivo by assessing muscle function during fatigue. Methods Twenty-four male mice were used. Each mouse received an injection of sterile 0.9% saline solution (50 µL) in the right tibialis anterior muscle, after which the tendon of the muscle was exposed, connected to an isometric transducer and subjected to a resting tension of 1 g. A bipolar electrode was attached to the tibial nerve for electrical stimulation. The mice were randomly allocated to one of two groups: G1 (control: 3 h – n=8 and 9 h – n=5) and G2 (treated with GaAlAs laser, λ660 nm, 35 mW, 0.6 J, 17 s: 3 h – n=6 and 9 h – n=5). Results In G1 mice, the amplitude of the tetanic contracture in response to induced fatigue remained unchanged during six consecutive tetani. The amplitude of the tetanic contractions in response to electrical stimulation (4-8 mV) was also unchanged. These results indicated muscle intactness in response to the load imposed by tetanus. In G2 mice, there was an increase in the amplitude of contraction after 3 h and 9 h when compared to G1 at 83% tetanus. Conclusion These results indicate that exposure of muscle to LLLT enhanced the contractile force and increased the resistance to muscle fatigue without causing morphological damage to cellular structures.

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Introduction: Brazil has seen a rise in the number of undergraduate courses in Medical Physics in recent years, as well as initiatives for the organization of graduation programs and clinical residencies in this multidisciplinary area. The purpose of the present study was to perform a data survey on academic training in Medical Physics in Brazil in the undergraduate, graduate, and residency levels until 2012. Methods The relevant information was requested for the leads of the training/teaching programs, which filled specific electronic forms. The data survey was accomplished by sending the forms to 38 educational institutions. Results The majority (90%) of the contacted institutions returned their specific requested information. It was estimated an offer of 400 enroll admissions per year in the group of institutions that offer undergraduate programs in Medical Physics. Federal or state public educational institutions offer around 61% of these admissions and 39% are offered by private universities. The average number of candidate competition was estimated on 3.6 ± 3.9 applicants per place in undergraduate programs, and the student’s complete the courses in 5.1 ± 0.7 years. The average number of undergraduate degrees awarded per year is 10.6 ± 7.3. At least 80% of educational programs have compulsory internships in their curricula with average duration of 307 ± 99 hours. In the graduation programs it was verified that the average time for concluding the programs were 2.2 ± 0.2 years, 4.1 ± 0.2 years and 4.7 ± 0.6 years for the MSc, PhD and direct-PhD, respectively. The programs have CAPES ratings varying from 4 to 7. Finally, until 2012 the residence programs offered 31 positions per year and the professional development programs (not residence) provide 7 positions per year. Conclusion It is understood that the presented numerical results offer a reliable scenario for the diagnosis of opportunities and scholarships distributions in each region of the country. These results may provide support for the improvement of resource distribution and the definition of public policies that can guide the adequacy of the distribution of courses in the three modalities of Medical Physics Education in the country.

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Abstract Introduction Locked-In Syndrome is admittedly the worst case of motor and speech impairment, it seriously damages the ability of oral and gestural communication of patients. In recent years, alternative and augmentative communication technology has provided resources to restore these patients' ability to communicate. Methods In order to relate and classify the main methods with that purpose, this work conducted a systematic review on several journal databases. Results We found 203 related papers and 55 of them were selected to compose the study. After that, we classified them into three major groups and we identified the main difficulties when using each approach. Conclusion In order to overcome these difficulties, we propose a new system concept to develop an adaptive, robust and low cost communication environment. The proposed system is composed of five modules: data entry, communication, aid to the caregiver and external interaction.

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Introduction A problem posed by electrical field (E) stimulation of biological preparations with high excitation threshold is that the E intensity required for excitation is likely to induce water electrolysis at the electrode surface, which can alter the extracellular medium and cause deleterious effects on the cells. In this study, different electrode materials and geometries were tested aiming at identifying electrode configurations that could transduce the E intensity required for exciting ventricular cardiomyocytes isolated from neonatal rats (threshold E ~30 V/cm) without causing water electrolysis. Methods Wire and plate electrodes made of platinum, stainless steel and nickel/chrome alloy were used. The effect of blasting the electrode surface with sand and NaHCO3 solution was also tested. Electrodes were inserted into a cell perfusion chamber containing the saline solution routinely used for physiological experiments. During E application for 5 min, the electrode surface and its surroundings were examined at high magnification for the presence of microbubbles, which indicates the occurrence of water electrolysis. The greatest E intensity applied that failed to generate microbubbles (En) was estimated. Results While nickel/chrome and stainless steel electrodes resulted in low En values, the best performance was observed for sandblasted platinum wire (2 mm diameter) and plate (25 mm x 5 mm; 0.1 mm thickness) electrodes, for which Enwas ≥40 V/cm. Conclusion These electrode configurations are suitable for effective and safe stimulation of isolated neonatal cardiomyocytes.

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Introduction In this paper, we present the initial results of a fully programmable 128-channel FPGA and PC-based system that has been developed for medical ultrasound (US) imaging research in our University laboratory (Federal University of Technology - Paraná, Brazil). Methods In order to demonstrate the feasibility of the US research system, two applications involving unfocused plane wave transmission and conventional B-mode beamforming were evaluated using a commercial tissue-mimicking phantom and a 3.2 MHz 128-element convex array transducer. Results Testing results show that the hardware platform is able to synthesize arbitrary pulses up to 100 Vpp with second order harmonic distortion below 80 dB. For the first application, a 41-tap digital FIR bandpass filter was applied to the acquired RF echoes, sampled at 40 MHz with 12-bit resolution, to improve the noise suppression. In the second application, after offline apodization weighting, filtering, delay-and-sum processing, envelope detection, log compression and scan conversion, the reconstructed B-mode image is displayed over a 50 dB range. Discussion The presented results indicate that the open US imaging system can be used to support different ultrasonic transmission and reception strategies, which typically cannot be implemented in conventional data flow architectures that are mainly based on hardware.