Ultrasonic Sensor: A Fast and Non-Destructive System to Measure the Viscosity and Density of Molecular Fluids.

This study presents the design and development of an ultrasonic sensor as a fundamental tool for characterizing the properties of fluids and biofluids. The analysis primarily focuses on measuring the electrical parameters of the system, which correlate with the density and viscosity of the solutions, in sample volumes of microliters and with high temporal resolution (up to 1 data point per second). The use of this sensor allows the fast and non-destructive evaluation of the viscosity and density of fluids deposited on its free surface. The measurements are based on obtaining the impedance versus frequency curve and the phase difference curve (between current and voltage) versus frequency. In this way, characteristic parameters of the transducer, such as the resonance frequency, phase, minimum impedance, and the quality factor of the resonant system, can characterize variations in density and viscosity in the fluid under study. The results obtained revealed the sensor's ability to identify two parameters sensitive to viscosity and two parameters sensitive to density. As a proof of concept, the unfolding of the bovine albumin protein was studied, resulting in a curve that reflects its unfolding kinetics in the presence of urea.

Collaborative Oscillatory Fracture.

We report a new oscillatory propagation of cracks in thin films where three cracks interact mediated by two delamination fronts. Experimental observations indicate that delamination fronts joining the middle crack to the lateral crack tips swap contact periodically with the crack tip of the middle crack. A model based on a variational approach analytically predicts the condition of propagation and geometrical features of three parallel cracks. The stability conditions and oscillating propagation are found numerically and the predictions are in favorable agreement with experiments. We found that the physical mechanism selecting the wavelength structure is a relaxation process in which the middle crack produces a regular oscillatory path.

Intertwined Multiple Spiral Fracture in Perforated Sheets.

We study multiple tearing of a thin, elastic, brittle sheet indented with a rigid cone. The n cracks initially prepared symmetrically propagate radially for n≥4. However, if n<4 the radial symmetry is broken and fractures spontaneously intertwine along logarithmic spiral paths, respecting order n rotational symmetry. In the limit of very thin sheets, we find that fracture mechanics is reduced to a geometrical model that correctly predicts the maximum number of spirals to be strictly 4, together with their growth rate and the perforation force. Similar spirals are also observed in a different tearing experiment (this time up to n=4, in agreement with the model), in which bending energy of the sheet is dominant.

Control autonómico del ritmo cardiaco, lactato sanguíneo y aceleración durante un combate simulado en atletas de taekwondo de elite / Autonomic control of heart rate, blood lactate and acceleration during combat simulation in taekwondo elite athletes

Propósito: el objetivo del estudio fue determinar la frecuencia cardiaca de recuperación (FCR), lactato sanguíneo y aceleración pico (ACCp) durante un combate simulado de atletas de taekwondo de elite. Métodos: doce (n = 12) sujetos varones, seleccionados nacionales y con más de cinco años de práctica en esta disciplina participaron en el estudio. Los atletas realizaron un combate simulado de tres asaltos de dos minutos con un minuto de pausa entre ellos, evaluando los siguientes parámetros: (¡) lactato sanguíneo al final de cada minuto de descanso entre asaltos; (¡¡) FCR a los treinta y sesenta segundos en cada minuto de descanso; (¡¡¡) ACCp en cada asalto disputado. El nivel de significancia se propuso a un valor de p 0,05) a los treinta y sesenta segundos en ninguna de las pausas, en el delta de lactato sanguíneo al final de cada pausa (p > 0,05), en la aceleración pico por round (p > 0,05) y en la aceleración promedio del combate (p = 0,18). Tampoco se encontraron correlaciones entre delta de lactato y FCR (r = -0,23; p = 0,18), entre delta de lactato y ACCp (r = 0,01; p = 0,93), y entre ACCp y FCR (r = 0,003; p = 0,98). Conclusiones: los datos sugieren que las variables estudiadas no serían determinantes en el resultado final de un combate simulado. Otros factores, como variables técnico/tácticas o psicológicas, podrían influir de manera significativa en el rendimiento deportivo (AU)

Purpose: the aim of the study was to measure the heart rate recovery, blood lactate and movement acceleration during simulated taekwondo competition. Methods: twelve male subjects who belong to the national team, with at least five years of experience participated in this research. They performed a simulated combat to evaluate the following variables: (i) Blood lactate after one minute recovery between each round, (ii) Heart rate recovery (HRR) at thirty and sixty seconds in each minute rest between rounds, (iii) Peak acceleration (ACCp) in each round performed. The significance level was set at p 0.05), blood lactate (p > 0.05), peak acceleration (p > 0.05) and the average acceleration of combat (p = 0.18). There was no correlation between delta lactate and ACCp (r = 0.01; p = 0.93), delta lactate and HRR (r = -0.23; p = 0.18), and ACCp and HRR (r = 0.003; p = 0.98). Conclusions: these data suggest that studied variables would not be decisive in the simulated combat outcomes. Other factors such as technical-tactical or psychological variables could have a significant impact on athletic performance (AU)

[AUTONOMIC CONTROL OF HEART RATE, BLOOD LACTATE AND ACCELERATION DURING COMBAT SIMULATION IN TAEKWONDO ELITE ATHLETES]. / CONTROL AUTONÓMICO DEL RITMO CARDIACO, LACTATO SANGUÍNEO Y ACELERACIÓN DURANTE UN COMBATE SIMULADO EN ATLETAS DE TAEKWONDO DE ELITE.

PURPOSE: the aim of the study was to measure the heart rate recovery, blood lactate and movement acceleration during simulated taekwondo competition. METHODS: twelve male subjects who belong to the national team, with at least five years of experience participated in this research. They performed a simulated combat to evaluate the following variables: (i) Blood lactate after one minute recovery between each round, (ii) Heart rate recovery (HRR) at thirty and sixty seconds in each minute rest between rounds, (iii) Peak acceleration (ACCp) in each round performed. The significance level was set at p < 005. RESULTS: the results showed no significant differences between winners and losers in the HRR at both, thirty and sixty seconds (p > 0.05), blood lactate (p > 0.05), peak acceleration (p > 0.05) and the average acceleration of combat (p = 0.18). There was no correlation between delta lactate and ACCp (r = 0.01; p = 0.93), delta lactate and HRR (r = -0.23; p = 0.18), and ACCp and HRR (r = 0.003; p = 0.98). CONCLUSIONS: these data suggest that studied variables would not be decisive in the simulated combat outcomes. Other factors such as technical-tactical or psychological variables could have a significant impact on athletic performance.

Propósito: el objetivo del estudio fue determinar la frecuencia cardiaca de recuperación (FCR), lactato sanguíneo y aceleración pico (ACCp) durante un combate simulado de atletas de taekwondo de elite. Métodos: doce (n = 12) sujetos varones, seleccionados nacionales y con más de cinco años de práctica en esta disciplina participaron en el estudio. Los atletas realizaron un combate simulado de tres asaltos de dos minutos con un minuto de pausa entre ellos, evaluando los siguientes parámetros: (¡) lactato sanguíneo al final de cada minuto de descanso entre asaltos; (¡¡) FCR a los treinta y sesenta segundos en cada minuto de descanso; (¡¡¡) ACCp en cada asalto disputado. El nivel de significancia se propuso a un valor de p < 0,05. Resultados: los resultados muestran que no hubo diferencias significativas entre ganadores y perdedores en la FCR (p > 0,05) a los treinta y sesenta segundos en ninguna de las pausas, en el delta de lactato sanguíneo al final de cada pausa (p > 0,05), en la aceleración pico por round (p > 0,05) y en la aceleración promedio del combate (p = 0,18). Tampoco se encontraron correlaciones entre delta de lactato y FCR (r = -0,23; p = 0,18), entre delta de lactato y ACCp (r = 0,01; p = 0,93), y entre ACCp y FCR (r = 0,003; p = 0,98). Conclusiones: los datos sugieren que las variables estudiadas no serían determinantes en el resultado final de un combate simulado. Otros factores, como variables técnico/tácticas o psicológicas, podrían influir de manera significativa en el rendimiento deportivo.

Experiencia con clozapina en esquizofrenia resistente / Experience with clozapine in ressistant schizophrenia

Se presenta una experiencia de tratamiento con clozapina en 11 pacientes esquizofrénicos resistentes. Se discute la eficacia del tratamiento y sus efectos adversos, así como la metodología empleada

Psicoeducación en familiares de pacientes esquizofrénicos en tratamiento con clozapina / Psycoeducation in the family of schizophrenic patients treated with clozapine

Se presenta una experiencia en psicoeducación de familiares de pacientes esquizofrénicos en tratamiento con Clozapina. Se describe el programa y actividades del taller realizados; además, se revisan y discuten los resultados obtenidos en la evaluación del taller. Concluimos que este tipo de experiencia es útil, tanto para los familiares como para el equipo terapéutico, lo que tendería a optimizar el tratamiento con Clozapina