Heart Rate Variability: a Follow-up in Elite Soccer Players Throughout the Season.

Heart rate variability (HRV) can provide useful information on physiological adaptations to training, but its role is unknown in professional soccer. The aim of this study was to determine an HRV profile in professional soccer over a season. A total of 504 records were made of the heart beat signal throughout a season from 22 professional soccer players. HRV was recorded in a sitting position, early morning and fasting for a period of 10 min. Standard deviation 1 and 2 (SD1, SD2), standard deviation of normal to normal R-R intervals (SDNN), Root Mean Square of the Successive Differences (rMSSD), percentage of RR intervals > 50 ms (pNN50), Sample Entropy (SampEn), Stress Score (SS) and sympathetic/parasympathetic ratio (S/PS ratio) were calculated. SDNN, rMSSD, pNN50, SD1 and SD2 showed an identical behaviour throughout the season, with lower values in the pre-season and the end of the season. SS and S/PS ratio indicated a sympathetic stress alert in the same periods. A weekly recording of the HRV over a 10 min period that includes a Poincaré plot with SS and S/PS ratio and at least one variable of the time domain is a useful tool for the follow-up of the individual assimilation of weekly workloads, including the game.

Ultrasonic drying of foodstuff in a fluidized bed: Parametric study.

The application of high power ultrasound for dehydration of porous materials may be very effective in processes in which heat-sensitive materials such as foodstuffs have to be treated. In fact, high-intensity ultrasonic vibrations are capable of increasing heat and mass transfer processes in materials. The application of ultrasonic energy can be made alone or in combination with other kind of energy such as hot-air. In this case, ultrasound helps in reducing temperature or treatment time. The aim of this work is to study the effect of air flow rate, ultrasonic power and mass loading on hot-air drying assisted by a new power ultrasonic system. The drying chamber is an aluminium vibrating cylinder, which is able to create a high intensity ultrasonic field in the gas medium. To that purpose the chamber is driven at its centre by a power ultrasonic vibrator at 21.8 kHz. Drying kinetics of carrot cubes and lemon peel cylinders were carried out at 40 degrees C for different air velocities, with and without ultrasound. The results show that the effect of ultrasound on drying rate is affected by air flow rate, ultrasonic power and mass loading. In fact, at high air velocities the acoustic field inside the chamber is disturbed and the effect of ultrasound on drying kinetics diminishes.

Food drying process by power ultrasound.

Drying processes, which have a great significance in the food industry, are frequently based on the use of thermal energy. Nevertheless, such methods may produce structural changes in the products. Consequently, a great emphasis is presently given to novel treatments where the quality will be preserved. Such is the case of the application of high-power ultrasound which represents an emergent and promising technology. During the last few years, we have been involved in the development of an ultrasonic dehydration process, based on the application of the ultrasonic vibration in direct contact with the product. Such a process has been the object of a detailed study at laboratory stage on the influence of the different parameters involved. This paper deals with the development and testing of a prototype system for the application and evaluation of the process at a pre-industrial stage. Such prototype is based on a high-power rectangular plate transducer, working at a frequency of 20 kHz, with a power capacity of about 100 W. In order to study mechanical and thermal effects, the system is provided with a series of sensors which permit monitoring the parameters of the process. Specific software has also been developed to facilitate data collection and analysis. The system has been tested with vegetable samples.

A procedure for the efficient selection of piezoelectric ceramics constituting high-power ultrasonic transducers.

The most characteristic narrow-band transducer structure for high-power ultrasonic applications is the well known piezoelectric sandwich which is reminiscent of the Langevin transducer. Such structure is generally used jointly with other components in the construction of industrial high-power transducers. One of the main objectives in the design and construction of such high-power transducers is to minimize energy losses. To that purpose the selection of the piezoelectric ceramic rings forming the sandwich requires clear and specific criteria. This paper deals with a numerical and experimental procedure for the accurate selection of the piezoelectric rings constituting high-power transducers, based on the analysis of the mechanical Q, the frequency and the resonance curve. The procedure was experimentally checked by constructing and characterizing several transducer structures.

Investigation of the influence of humidity on the ultrasonic agglomeration of submicron particles in diesel exhausts.

Removing very fine particles in the 0.01-1 micro m range generated in diesel combustion is important for air pollution abatement because of the impact such particles have on the environment. By forming larger particles, acoustic agglomeration of submicron particles is presented as a promising process for enhancing the efficiency of the current filtration systems for particle removal. Nevertheless, some authors have pointed out that acoustic agglomeration is much more efficient for larger particles than for smaller particles. This paper studies the effect of humidity on the acoustic agglomeration of diesel exhausts particles in the nanometer size range at 21 kHz. For the agglomeration tests, the experimental facility basically consists of a pilot scale plant with a diesel engine, an ultrasonic agglomeration chamber a dilution system, a nozzle atomizer, and an aerosol sampling and measuring station. The effect of the ultrasonic treatment, generated by a linear array of four high-power stepped-plate transducers on fumes at flow rates of 900 Nm(3)/h, was a small reduction in the number concentration of particles at the outlet of the chamber. However, the presence of humidity raised the agglomeration rate by decreasing the number particle concentration by up to 56%. A numerical study of the agglomeration process as a linear combination of the orthokinetic and hydrodynamic agglomeration coefficients resulting from mutual radiation pressure also found that acoustic agglomeration was enhanced by humidity. Both results confirm the benefit of using high-power ultrasound together with humidity to enhance the agglomeration of particles much smaller than 1 micro m.

Characterization of suspensions of particles in water by an ultrasonic resonant cell.

This paper presents a resonant technique to accurately measure phase-velocity and attenuation of longitudinal acoustic waves in suspensions of solid particles in water. The technique is based on exciting thickness resonances of a layer of fluid and analyzing its spectrum. To this end, a resonant cell to contain the fluid is described and used. Two different type of water suspensions are studied: titanium dioxide and alumina particles; particle volume fraction is in the range 0-0.18. Simultaneous determination of particle size distribution in the suspension by an optical method are also carried out. Finally, the experimental results are compared with theoretical predictions obtained from three different approaches.

Recent developments in vibrating-plate macrosonic transducers.

As is known, the stepped-plate transducer [Ultrasonics 16 (6) (1978) 267] represents an optimum system for the efficient generation of high-intensity sonic and ultrasonic radiation in fluid media. Nevertheless, the design of this transducer may be difficult to adapt to some specific problems. Such is the case of the treatment of large volumes in industrial installations. A solution is the enlargement of the surface of the radiating plate. However, that means to work at high-order vibration modes which implies numerous practical problems. Another case is the application of the stepped-plate transducer for the generation at sonic frequencies where the height of the steps of the radiating plate, which has to be half a wavelength of the radiation, becomes too high and it makes the transducer construction impractical. To face these specific situations a series of new designs in transducer development have been recently carried out. This paper presents the characteristics of two new transducer devices, one for the treatment of large industrial volumes and the other for low-frequency sonic applications. Both devices are based on vibrating-plate radiators and represent a novel approach to practical existing problems.

A macrosonic system for industrial processing

The development of high-power applications of sonic and ultrasonic energy in industrial processing requires a great variety of practical systems with characteristics which are dependent on the effect to be exploited. Nevertheless, the majority of systems are basically constituted of a treatment chamber and one or several transducers coupled to it. Therefore, the feasibility of the application mainly depends on the efficiency of the transducer-chamber system. This paper deals with a macrosonic system which is essentially constituted of a high-power transducer with a double stepped-plate radiator coupled to a chamber of square section. The radiator, which has a rectangular shape, is placed on one face of the chamber in order to drive the inside fluid volume. The stepped profile of the radiator allows a piston-like radiation to be obtained. The radiation from the back face of the radiator is also applied to the chamber by using adequate reflectors. Transducer-chamber systems for sonic and ultrasonic frequencies have been developed with power capacities up to about 5 kW for the treatment of fluid volumes of several cubic meters. The characteristics of these systems are presented in this paper.

Application of high-power ultrasound to enhance fluid/solid particle separation processes

The separation of fine particles from gases or liquids is a topic of permanent industrial attention. The use of ultrasonic energy to assist conventional separation techniques seems to be very promising. The adequate applications of high-intensity ultrasonic fields may contribute to improve the efficiency and capacity of the separation methods presently used. The specific mechanisms to ultrasonically enhance separation processes basically depend on the medium to be treated. In gas suspensions, where very fine particles have to be removed, ultrasonic action involves agglomeration of particles in order to increase their size and, consequently, to improve collection efficiency of conventional filters. In liquid suspensions, agglomeration is, in general, less efficient than in gases. Nevertheless, the ultrasonic energy is useful to dewater fine-particle high-concentration suspensions such as slurries and sludges. This paper deals with the application of acoustic energy to assist fluid/solid separation processes in gas and liquid suspensions and presents some theoretical and experimental results in specific applications.

Tumores germinales gonadales en niños: experiencia en el SA: Hospital de Niños JM de Los Ríos 1985-1998 / Tumor germinal gonadal in children: experience in the SA: Hospital de Niños JM de Los Ríos 1985-1998

Entre enero 1985 y agosto 1998, 68 pacientes 137 pacientes con diagnóstico de Tumores Germinales (TG) ingresaron al S.A. Hospital de Niños J.M. de Los Ríos. De ellos, 68 pacientes con Tumor Germinal Gonadal (TGG) fueron incluidos en el protocolo 0021/85, todos se consideraron evaluables. 22 pacientes eran varones, la relación sexo V:H 1:2,09. El promedio de edad fue de 6,6 a., con una mínima de 4 meses y máxima de 17 años. Los síntomas y signos más frecuentes fueron: Masa 73,5 por ciento, Dolor 45,6 por ciento. Marcadores se determinaron en 26 pacientes (38,23 por ciento), resultando positivos en 16 pacientes La variedad histológica más frecuente fue: Teratoma Maduro (TM) 33 casos (48,52 por ciento), Tumor del Seno Endodérmico (TSE) 15 casos (22,05 por ciento), Teratoma Inmaduro (TI) 11 casos (16,17 por ciento), Disgerminoma (DSG) 8 casos (11,76 por ciento) y 1 caso Germinal Mixto (GM). Se utilizó el sistema de Estadiaje propuesto por Brodeur: Estadio I 48 pacientes (70,58 por ciento), Estadio II 10 pacientes (14,70 por ciento), Estadio III 9 pacientes (13,23 por ciento), Estadio IV 1 paciente (1,47 por ciento). Cirugía fue empleada como terapia inicial en todos los casos. Quimioterapia se utilizó en 24: 15 pacientes recibieron esquema PVB, y 6 pacientes esquema VIP Radioterapia fue administrada en 3 pacientes (4,41 por ciento). Respuesta Completa se obtuvieron en 62 pacientes (91,14 por ciento), Respuesta Parcial en 3 pacientes (4,41 por ciento) y Progresión 3 pacientes (4,41 por ciento). Sólo 2 pacientes fallaron a la terapia. La SLE según Histología fue: TM 100 por ciento a 159 meses, TSE 90 por ciento a 147 meses, TI 90 por ciento a 161 meses, DSG 100 por ciento a 135 meses; según Estadio: Est. I 100 por ciento a 159 meses, Est. II 87,5 por ciento a 141 meses, Est. III 100 por ciento a 161 meses; según esquema: PVB 90 por ciento a 161 meses, VIP 80 por ciento a 47 meses. No se demostró diferencia estadística significativa. La SLE general fue de 9677 por ciento a 161 meses. 3 pacientes fallecieron, la Sobrevida Global por Histología fue TM 100 por ciento a 159 meses, TSE 86,66 por ciento a 147 meses, TI 100 por ciento a 161 meses, DSG 87,5 por ciento a 135 meses; según Estadio: Est. I 100 por ciento a 159 meses, Est. II 70 por ciento a 141 meses, Est. III 100 por ciento a 161 meses; según Esquema: PVB 80 por ciento a 161 meses, VIP 100 por ciento a 47 meses. No se demostró diferencia estadística significativa

Paludismo y embarazo / Paludismo and pregnancy

Estudia los casos de malaria en embarazadas en el período comprendido entre 1990-1995 en el Hospital Gineco-Obstétrico Enrique C. Sotomayor, las principales complicaciones fueron: anemia, hipoglicemia, aborto y prematuridad. La tasa de mortalidad fue del 4xciento, las causas fueron encefalopatía y coma; la quimioprofilaxis y las medidas de protección personal en mujeres embarazadas deben ser tomadas para reducir los riesgos tanto en la madre como en el feto...

Patología neoplásica de la cavidad bucal. Estudio de su frecuencia en el servicio de patología bucal de la Facultad de Estomatología / Neoplasms of the oral cavity. A study of their frequency at the oral pathology service of the Stomatology Faculty

Las neoplasias bucales constituyen un grupo numeroso y variable de lesiones que deben ser conocidas profundamente por el estomatólogo dada su responsabilidad en el diagnóstico de éstos. Este conocimiento debe abarcar los aspectos no sólo de las características clínicas de éstas, sino también aspectos relacionados con su frecuencia y características histológicas. Basado en estos elementos y ante la carencia de informes de este tipo en nuestro medio se realiza esta investigación con los objetivos de determinar la cantidad de neoplasias presentes en una serie de informes anatomopatológicos, así como clasificar y correlacionar éstos con edad, sexo y localización. Se estudian los archivos biópsicos delservicio de anatomía patológica de la Facultad de Estomatología donde se seleccionan las neoplasias de la boca, se clasifican y correlacionan , de acuerdo con el tipo hístico, edad, sexo y localización(AU)

[Quantification of ventricular volume. Comparative study of 2 angiographic methods]. / "Cuantificación de los volúmenes ventriculares: estudio comparativo de 2 métodos angiográficos".

The left ventricular volumes and the ejection fraction were measured in 78 patients who had different cardiopathies, in more than 50% the diagnosis of ischaemic heart disease of coronary origin was made. Every cineangiocardiogram was carefully observed to find those who had normal and abnormal ventricular contraction. The ventricular volumes were calculated by the Green method and afterwards the results were compared with the values obtained by the Sandler and Dodge method. A very good correlation was found between the two methods and we got the conclusion that although it is preferable to calculate ventricular volumes and the ejection fraction with biplane method or with Saudler and Dodge's monoplane, the results of the present work permit the use of Green's method in calculating ventricular volumes and obtaining confident results, independently of the ventricular contraction type with the exception of those who have large ventricular aneurisms.

[Phonomechanocardiography of constrictive pericarditis]. / Estudio fonomecanocardiográfico de la pericarditis constrictiva.

There were studied 19 constrictive pericarditis cases demonstrated by anatomist study. It was evident, at all of them, systemic veiny hypertension's syndrome. "Extinguished" cardiac noises and "quiet" heart only appeared at the 42% of the cases. 73% of patients were found with important incapacity. Lyan's pericardic protodiastolic crack was registered at the 75% of the cases and only at 2 cases (10.9%) it was found reinforcement of pulmonary noise II. It is agree with the haemodynamic discovery of pulmonary pression's light elevation. Characteristically, precordiogrammes showed great "A" wave, and it was agree with telediastolic pression's elevation of the two ventricles obtained by catheterism. Phlebogramme was characteristic of systemic veiny hypertension by impediment of ventricular filled at all the studied cases. Measurement of cardiac cycle's phases showed diminution at PE, Blumberger's intrasystolic quotient, left expulsion fraction (Carrard's method) and ventricular pression's elevation middle velocity (VPEMV). By the contrary Weissler's index was found elevated. Eventhough found ciphers could be considered like bordering normal values, there is a difference statistically significance in relation with the values that were found in sane subjects. These discoveries were interpreted in the base that the patient's heart with constrictive pericarditis acts at the curve's ascendent part of the ventricular function because it has incapacity to utilize Starling's mechanism. Process' chronicity produces myocardic atrophy by "discuss" and, by this, ventricular function's improvement can be no immediate to pericardiectomy. Apexcardiogramme shows the impedement to ventricular filled with its diastolic morphology which is very similar to intracavitary pression's curve ("square root's image"). It is postuled the hypothesis that these sicks do not develop important pulmonary hypertension, because right ventricle's poor diastolic distension impides generation of major expense and systolic pression and, by other side, the impedement to ventricular filled has repercussion over right auricle and systemic veiny territory much more distensible, with the known clinical consequences.