22 research outputs found
Tailor-Made Tissue Phantoms Based on Acetonitrile Solutions for Microwave Applications up to 18 GHz
(c) 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.Tissue-equivalent phantoms play a key role in the development of new wireless communication devices that are tested on such phantoms prior to their commercialization. However, existing phantoms cover a small number of tissues and do not reproduce them accurately within wide frequency bands. This paper aims at enlarging the number of mimicked tissues as well as their working frequency band. Thus, a variety of potential compounds are scanned according to their relative permittivity from 0.5 to 18 GHz. Next, a combination of these compounds is characterized so the relation between their dielectric properties and composition is provided. Finally, taking advantage of the previous analysis, tailor-made phantoms are developed for different human tissues up to 18 GHz and particularized for the main current body area network (BAN) operating bands. The tailor-made phantoms presented here exhibit such a high accuracy as would allow researchers and manufacturers to test microwave devices at high frequencies for large bandwidths as well as the use of heterogeneous phantoms in the near future. The key to these phantoms lies in the incorporation of acetonitrile to aqueous solutions. Such compounds have a suitable behavior to achieve the relative permittivity values of body tissues within the studied frequency band.This work was supported by the Ministerio de Economia y Competitividad, Spain (TEC2014-60258-C2-1-R) and by the European FEDER Funds.Castelló-Palacios, S.; García Pardo, C.; Fornés Leal, A.; Cardona Marcet, N.; Vallés Lluch, A. (2016). Tailor-Made Tissue Phantoms Based on Acetonitrile Solutions for Microwave Applications up to 18 GHz. IEEE Transactions on Microwave Theory and Techniques. 64(11):3987-3994. https://doi.org/10.1109/TMTT.2016.2608890S39873994641
Spatial In-Body Channel Characterization Using an Accurate UWB Phantom
"(c) 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works."Ultra-wideband (UWB) systems have emerged as a possible solution for future wireless in-body communications. However, in-body channel characterization is complex. Animal experimentation is usually restricted. Furthermore, software simulations can be expensive and imply a high computational cost. Synthetic chemical solutions, known as phantoms, can be used to solve this issue. However, achieving a reliable UWB phantom can be challenging since UWB systems use a large bandwidth and the relative permittivity of human tissues are frequency dependent. In this paper, a measurement campaign within 3.1-8.5 GHz using a new UWB phantom is performed. Currently, this phantom achieves the best known approximation to the permittivity of human muscle in the whole UWB band. Measurements were performed in different spatial positions, in order to also investigate the diversity of the in-body channel in the spatial domain. Two experimental in-body to in-body (IB2IB) and in-body to on-body (IB2OB) scenarios are considered. From the measurements, new path loss models are obtained. Besides, the correlation in transmission and reception is computed for both scenarios. Our results show a highly uncorrelated channel in transmission for the IB2IB scenario at all locations. Nevertheless, for the IB2OB scenario, the correlation varies depending on the position of the receiver and transmitter.This work was supported by the Ministerio de Economia y Competitividad, Spain, under Grant TEC2014-60258-C2-1-R and Grant TEC2014-56469-REDT and by the European FEDER Funds.Andreu Estellés, C.; Castelló Palacios, S.; García Pardo, C.; Fornés Leal, A.; Vallés Lluch, A.; Cardona Marcet, N. (2016). Spatial In-Body Channel Characterization Using an Accurate UWB Phantom. IEEE Transactions on Microwave Theory and Techniques. 64(11):3995-4002. doi:10.1109/TMTT.2016.2609409S39954002641
Amphipathic Substrates Based on Crosslinker-Free Poly(epsilon-Caprolactone):Poly(2-Hydroxyethyl Methacrylate) Semi-Interpenetrated Networks Promote Serum Protein Adsorption
[EN] A simple procedure has been developed to synthesize uncrosslinked soluble poly(hydroxyethyl methacrylate) (PHEMA) gels, ready for use in a subsequent fabrication stage. The presence of 75 wt % methanol (MetOH) or dimethylformamide (DMF) impedes lateral hydroxyl-hydroxyl hydrogen bonds between PHEMA macromers to form during their solution polymerization at 60 degrees C, up to 24 h. These gels remain soluble when properly stored in closed containers under cold conditions and, when needed, yield by solvent evaporation spontaneous physically-crosslinked PHEMA adapted to the mould used. Moreover, this two-step procedure allows obtaining multicomponent systems where a stable and water-affine PHEMA network would be of interest. In particular, amphiphilic polycaprolactone (PCL):PHEMA semi-interpenetrated (sIPN) substrates have been developed, from quaternary metastable solutions in chloroform (CHCl3):MetOH 3:1 wt. and PCL ranging from 50 to 90 wt % in the polymer fraction (thus determining the composition of the solution). The coexistence of these countered molecules, uniformly distributed at the nanoscale, has proven to enhance the number and interactions of serum protein adsorbed from the acellular medium as compared to the homopolymers, the sIPN containing 80 wt % PCL showing an outstanding development. In accordance to the quaternary diagram presented, this protocol can be adapted for the development of polymer substrates, coatings or scaffolds for biomedical applications, not relying upon phase separation, such as the electrospun mats here proposed herein (12 wt % polymer solutions were used for this purpose, with PCL ranging from 50% to 100% in the polymer fraction).This research was funded by the Spanish Ministerio de Economia y Competitividad, grant number DPI2015-65401-C3-2-R.Vilariño, G.; Salgado-Gallegos, A.; De-La-Concepción-Ausina, J.; Rodriguez-Hernandez, J.; Shahrousvand, M.; Vallés Lluch, A. (2020). Amphipathic Substrates Based on Crosslinker-Free Poly(epsilon-Caprolactone):Poly(2-Hydroxyethyl Methacrylate) Semi-Interpenetrated Networks Promote Serum Protein Adsorption. Polymers. 12(6):1-14. https://doi.org/10.3390/polym12061256S11412
Experimental Path Loss Models for In-Body Communications Within 2.36-2.5 GHz
"(c) 2015 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works."Biomedical implantable sensors transmitting a variety
of physiological signals have been proven very useful in the
management of chronic diseases. Currently, the vast majority of
these in-body wireless sensors communicate in frequencies below
1 GHz. Although the radio propagation losses through biological
tissues may be lower in such frequencies, e.g., the medical implant
communication services band of 402 to 405 MHz, the maximal
channel bandwidths allowed therein constrain the implantable
devices to low data rate transmissions. Novel and more sophisticated
wireless in-body sensors and actuators may require higher
data rate communication interfaces. Therefore, the radio spectrum
above 1 GHz for the use of wearable medical sensing applications
should be considered for in-body applications too. Wider channel
bandwidths and smaller antenna sizes may be obtained in frequency
bands above 1 GHz at the expense of larger propagation
losses. Therefore, in this paper, we present a phantom-based radio
propagation study for the frequency bands of 2360 to 2400 MHz,
which has been set aside for wearable body area network nodes,
and the industrial, scientific, medical band of 2400 to 2483.5 MHz.
Three different channel scenarios were considered for the propagation
measurements: in-body to in-body, in-body to on-body, and
in-body to off-body.We provide for the first time path loss formulas
for all these cases.Chavez-Santiago, R.; García Pardo, C.; Fornés Leal, A.; Vallés Lluch, A.; Vermeeren, G.; Joseph, W.; Balasingham, I.... (2015). Experimental Path Loss Models for In-Body Communications Within 2.36-2.5 GHz. IEEE Journal of Biomedical and Health Informatics. 19(3):930-937. doi:10.1109/JBHI.2015.2418757S93093719
Evaluación interactiva del aprendizaje de Investigación Operativa basada en juegos mediante la plataforma Kahoot!
[EN] Emerging technologies and mobile platforms allow the introduction of new
teaching and learning strategies, in particular new ways to implement games
in higher education. Kahoot! is a free platform, which can be used by teachers
to develop games for classroom activities. Although this tool is the most used
mobile app and one of the first to be used in education, there are no studies
about its application in learning Operations Research. The objective of this
paper is to evaluate Kahoot's capabilities for continuous assessment, as well
as its contribution in improving students´ motivation, learning and
performance in decision making tecniques. As positive outcomes we can
highlight that the majority of students think Kahoot is a fun experience and
that it is also useful when revising concepts. Moreover, Kahoot games increase
student´engagement and provide immediate feedback for both teacher and
student. In addition, results about student´s performance and motivation are
presented.[ES] Las nuevas tecnologías y aplicaciones móviles facilitan la implantación de nuevas estrategias de enseñanza-aprendizaje y en particular nuevas formas de implementar juegos en educación superior. Kahoot! es una plataforma gratuita con la que el profesor puede crear juegos para utilizar en el aula. Aunque esta herramienta es la aplicación móvil más utilizada y una de las primeras en educación, no hay estudios publicados sobre su utilización en el apredizaje de Investigación Operativa. El objetivo de este trabajo es la evaluación de las prestaciones de Kahoot para la evaluación continua, así como la contribución de esta herramienta para mejorar la motivación, el aprendizaje y el rendimiento de los alumnos en las técnicas de toma de decisiones empresariales. Como resultados positivos podemos destacar que la mayoría de los alumnos consideran que es divertido, que representa una buena herramienta para repasar conceptos. Además aumenta la participación durante las clases y aporta un feedback inmediato tanto al alumno como al profesor. Asimismo, presentamos resultados sobre el rendimiento y la motivación de los alumnos.Segura Maroto, M.; Maroto Álvarez, MC.; Ginestar Peiro, CDM.; Navarro Cerdán, JR.; Martón Lluch, I. (2019). Evaluación interactiva del aprendizaje de Investigación Operativa basada en juegos mediante la plataforma Kahoot!. En IN-RED 2019. V Congreso de Innovación Educativa y Docencia en Red. Editorial Universitat Politècnica de València. 1658-1671. https://doi.org/10.4995/INRED2019.2019.10381OCS1658167
Estudio de la viabilidad de la eliminación de semillas de malas hierbas en el suelo por radiación de microondas
¿Informamos correctamente al paciente cuando prescribimos un antibiótico?
ObjetivoDescribir la información médica recibida por el paciente cuando se le prescribe un antibiótico.DiseñoDescriptivo, observacional, multicéntrico.EmplazamientoCiudad de Castellón, ciudad de Valencia y provincia de Valencia. (Sagunto, Godella y Canet d’En Berenguer).ParticipantesPacientes que acudieron a 15 farmacias que aceptaron colaborar en la recogida de datos. La muestra calculada para un nivel de confianza del 95% y un riesgo alfa del 0,5% fue de 216 pacientes.MedicionesEncuesta de 8 preguntas de respuesta cerrada (tabla 1) administrada aleatoriamente por los farmacéuticos a una muestra de la población de estudio. Se distribuyeron 15 encuestas por farmacia.ResultadosRespondió el 96% de los encuestados. La media de edad fue de 45,5 ± 22,3 años, el 36,4% era varón y el 63,6%,mujer. En el 89,9% de los pacientes (intervalo de confianza [IC] del 95%, 85,8-93,8%) su médico le indicó la duración del tratamiento y al 96,3% (IC del 95%, 92,8-98,4%), la periodicidad de las tomas. El 87% (IC del 95%, 82-91%) recuerda las instrucciones orales. El 84,7% (IC del 95%, 79,4-89,1%) de los que las recibieron por escrito entendió lo pautado. Recibió únicamente indicaciones orales un 25,5% de los pacientes (IC del 95%, 19,7-31,1%), mientras que un 36,9% las recibió sólo por escrito (IC del 95%, 30,2-43%) y un 37,4% (IC del 95%, 30,6-43,5%), tanto orales como escritas. Al 26,4% (IC del 95%, 20,5-32,35%) se le aconsejó tomarlo con o sin alimentos y al 12,5% (IC del 95%, 8,09-17%) se le advirtió de los posibles efectos adversos. Los fármacos más prescritos fueron: amoxicilina-ácido clavulánico en el 32,9% (IC del 95%, 26-39%), amoxicilina en el 22,2% (IC del 95%, 16-27%), azitromicina en el 9,7% (IC del 95%, 5-14%), claritromicina en el 7,9% (IC del 95%, 4,7-12%), cefuroxima axetilo en el 7,4% (IC del 95%, 4-11%), ciprofloxacino en el 3,2% (IC del 95%, 1-6%), cefixima en el 3,2% (IC del 95%, 1-6%) y fosfomicina en el 2,30% (IC del 95%, 0,7-5%).Las enfermedades para las que se prescribieron fueron: infección respiratoria de las vías altas en el 45,8% (IC del 95%, 38-52%), infección de la cavidad bucal en el 19,4% (IC del 95%, 14-24%), infección de la vía respiratoria baja en el 14,9% (IC del 95%, 09-19%) e infección de la vía urinaria en el 10,4% (IC del 95%, 6-14%).Discusión y conclusionesNo hubo diferencias significativas en cuanto a la comprensión de órdenes orales o escritas. En la mayor parte de los casos no damos información sobre interacciones antibiótico-alimento, ni advertimos de posibles efectos secundarios.En nuestro estudio, los pacientes reciben siempre algún tipo de información, en contraposición a otras publicaciones1,2, que reflejan hasta un 17% de ausencia de ésta por parte del médico cuando prescribe un fármaco, tal vez porque nuestro trabajo está centrado exclusivamente en los antibióticos. No encontramos diferencias significativas entre mayores y menores de 65 años en cuanto a la comprensión de las instrucciones. En otra publicación sí hubo diferencias3,4, probablemente porque se indicaba al paciente que verbalizara lo que había entendido. El porcentaje de pacientes que recibieron instrucciones por escrito está en consonancia con las recomendaciones de la Food and Drug Administration para el año 2000, que planteaba como objetivo que el 75% de los pacientes saliera de las consultas con instrucciones escritas. No hemos encontrado publicaciones sobre la repercusión de la ausencia de información sobre interacción fármaco-alimento. No obstante, parece razonable insistir en este aspecto, ya que la biodisponibilidad de los antibióticos según se tomen con o sin alimentos puede verse alterada y condicionar su eficacia clínica
Chlortoluron levels and selectivity in wheat cultivars
Chlortoluron determination in seedlings of four wheat cultivars have been carried out by gas liquid chromatography with alkali flame-ionization detection. Recoveries through the method were always higher than 70% and the limit of detection was 0.01 ppm. Herbicide levels have been determined at different times after treatment. No significant differences among cultivars have been found in chlortoluron levels at the end of 24 h treatment, while six days after treatment susceptible cultivars showed levels of chlortoluron clearly higher than tolerant cultivars. A good correlation was observed between herbicide level and plant fresh weight in the studied cultivars six days after treatment. © 1989
Prevalencia de actividad física y su relación con variables sociodemográficas y ciertos estilos de vida en escolares cordobeses
BACKGROUND: Regular physical exercise is not a widespread habit among the population. Early childhood in a crucial stage for acquiring this habit. The objective of this study was that of ascertaining the behavior of school-age children with regard to the degree of physical activity they do and to examine the factors involved. METHODS: An observational study was conducted by means of a survey based on a questionnaire which 6th and 8th grade students in a Basic Health Care District of Cordoba (N-585) filled out on their own. Questions were asked regarding the frequency of exercise, preferences and prospects for practicing sports, the childrens physical shape and school physical education classes, in addition to other behavior comprising their lifestyles. A dual-variable (p<0.05) and a multiple-variable analysis was conducted employing logistic regression. RESULTS: A total of 548 students filled out the survey (response rate=97.8%). 79.3% (IC95% 75.7-82.6) were involved in extracurricular physical activities, 21.0% (IC95% 17.1-24.7%) being involved in intense physical exercise. 50.5% (IC95% 46.3-54.8) did not think that they were in good physical shape. The age, sex, type of residence, the involvement in sports on the part of their parents or a close friend and what they considered their degree of healthiness to be comprised the variables quite strongly linked to doing exercise (p<0.001). CONCLUSIONS: The prevalence of physical exercise is high, although it progressively decreased with age, especially for girls. A major number of students considered themselves to be in unsatisfactory physical condition.FUNDAMENTO: El ejercicio físico regular es una práctica poco extendida entre la población. La infancia es una etapa crucial para adquirir este hábito. El objetivo del estudio fue conocer la conducta de los escolares respecto al grado de actividad física que desarrollan y examinar los factores que se relacionan. MÉTODOS: Se llevó a cabo un estudio observacional mediante encuesta basada en un cuestionario autoadministrado a los escolares de 6º y 8º de Enseñanza General Básica de una Zona Básica de Salud de Córdoba (N=585). Se interrogó sobre la frecuencia de ejercicio, preferencias y expectativas para la práctica deportiva, estado de forma física y clases de educación física del colegio, además de otras conductas constitutivas de los estilos de vida. Se llevó a cabo un análisis bivariado (p<0,05) y multivariado con aplicación de regresión logística. RESULTADOS: Contestaron la encuesta un total de 548 alumnos (tasa de respuesta=97,8%). El 79,3% (IC 95%: 75,7-82,6) realizaban actividades físicas extraescolares, y el 21,0% (IC 95%: 17,7-24,7) ejercicio físico intenso. El 50,5% (IC 95%: 46,3-54,8) no consideran bueno su estado de forma física. La edad, el sexo, el tipo de residencia, la práctica deportiva en los padres o el amigo y estado de salud percibido constituyen las variables más fuertemente asociadas a la realización de ejercicio (p<0,001). CONCLUSIONES: Aunque la prevalencia de ejercicio físico es elevada, va declinando con la edad, sobre todo en las niñas. Un importante número de escolares consideran insatisfactorio su estado de forma física