Advantage of four-electrode over two-electrode defibrillators

Defibrillation is the standard clinical treatment used to stop ventricular fibrillation. An electrical device delivers a controlled amount of electrical energy via a pair of electrodes in order to reestablish the normal heart rate. We propose a new technique that is a combination of biphasic shocks applied with a four-electrode system rather than the standard two-electrode system. We use a numerical model of a one-dimensional ring of cardiac tissue in order to test and evaluate the benefit of such a new technique. We compare three different shock protocols, namely, a monophasic and two types of biphasic shocks. The results obtained by using a four-electrode system are compared quantitatively with those obtained with the standard two-electrode system. We find that a huge reduction in defibrillation threshold is achieved with the four-electrode system. For the most efficient protocol (asymmetric biphasic), we obtain a reduction in excess of 80 % in the energy required for a defibrillation success rate of 90 %. The mechanisms of successful defibrillation are also analyzed. This reveals that the advantage of asymmetric biphasic shocks with four electrodes lies in the duration of the cathodal and anodal phase of the shock

Biocombustibles en la agricultura: carácter renovable y análisis de emisiones

El uso de biocombustibles parece ser un factor importante de cara a retrasar el agotamiento de combustibles fósiles. En este trabajo se realiza una revisión de estudios de investigación muy recientes relacionados con el carácter renovable de la producción de biocombustibles (bioetanol y biodiesel), así como del comportamiento de los motores con estos nuevos carburantes y sus mezclas (etanol al 10%, biodiesel 100%, isobutileno+etanol también denominado bioETBE) desde el punto de vista de las emisiones de gases

Palaeoebiological implications of cuticle morphology, microstructure and formation in modern and fossil Daira (Decapoda, Brachyura, Dairoidea)

The origin and function of peculiar mushroom-shaped cuticular structures in some decapod crustaceans remains unknown. This ornamentation has appeared several times in widely disparate clades (in podotreme and heterotreme crabs, and pagurids). These structures are analysed in the modern genus Daira and compared with fossil material from the Eocene of Huesca and the Miocene of Alicante and Mallorca. A morphological and petrographic study is carried out using conventional microscopy and Scanning Electron Microscopy to understand the microstructure in modern and fossil representatives. This provides a clear view of the mushroom-like structures that cover the carapace of Daira and the distribution of the different layers of the exoskeleton. The results reveal a complex morphology, which involves all layers of the cuticle, with changes in the thickness of the exocuticle in different areas, and the presence of conical structures that especially affect the outer layers. These convolutions form a network of channels connected to the outside by pores. Finally, possible anti-predatory functions of these complex structures are proposed

New version of a laboratory impact device for firmness sensing of fruits.

Results of previous studies conducted by different researchers have shown that impact techniques can be used to evaluate firmness (Delwiche et al., 1989; Delwiche et al.;1996; Jaren et al., 1992; Ruiz Altisent et al., 1996). To impact the fruit with a small spherical impactor of known mass and radius of curvature and measure the acceleration of the impactor is a technique described by Chen et al. (1985) and used by several researchers for sensing fruit firmness (Jaren et al., 1992; Correa et al.; 1992). The advantages of this method vs. a force sensor that measures the force as a function of time is that the measured impact-acceleration response is independent of the fruit mass and is less sensitive to the variation in the radius of curvature of the fruit (Chen et al., 1996). Ruiz Altisent et al. (1993) developed and used a 50 g impactor with a 19 mm diameter spherical tip, dropping from different height for fruits (apples, pears, avocados, melons, peaches ...). Another impact device for firmness sensing of fruits was developed by Chen and Ruiz Altisent (1996). They designed and fabricated an experimental low-mass impact sensor for high-speed sensing of fruit firmness. The impactor consisted of a semi-spherical impacting tip attached to the end (near the centre of percussion) of a pivoting arm. Impact is done by swinging the impactor to collide with the fruit. It has been implemented for on-line use. In both devices a small accelerometer is mounted behind the impacting tip. Lateral impactor and vertical impactor have been used in laboratory and the results from non-destructive impact tests have contributed to standardise methods to measure fruit firmness: Barreiro (1992) compared impact parameters and results of Magness-Taylor penetration tests for apples, pears, apricots [and peaches; Agulheiro (1994) studied the behaviour of the impact parameters during seven weeks of cold storage of two melon varieties; Ortiz (1998) used low energy impact and NIR procedures to segregate non crispy, non firm and soft peaches. Steinmetz (1996) compared various non-destructive firmness sensors, based on sound, impact and micro-deformation

Morfología de vertientes y neotectónica en el Macizo de Javalambre (provincia de Teruel)

[Resumen] El modelado actual de las vertientes del macizo de Javalambre es consecuencia de tres tipos principales de procesos que actúan a partir de su elevación a comienzos del Plioceno -superior: (a) la dinámica periglaciar, (b) una etapa de activida~ tect6nica ocurrida hacia el Pleistoceno medio-superior, y (c) deslizamientos gravitacionales, translacionales y rotacionales producidos a favor de un sustrato plástico en las áreas de mayor incisión de la red -fluvial.Abstract] The present slope form in Javalambre area results from three principal types of processes which are active after its elevation in the early Upper Pliocene: (a) periglacial dynamics, (b) a tectonic phase in Middle-Upper Pleistocene, and (c) gravitational, translational and rotational landslides generated over plastic rocks in zones with a intensive fluvial incisio

Evaluation of soil mechanic resistance and seed depth placement in a maize crop seed under different soil management practices

Com o objetivo de estudar a influência da resistência mecânica do solo na distribuição vertical de semente obtida por semeadores numa cultura de milho, realizou-se na campanha de 2011 um estudo de campo na região do Alentejo, sendo a operação de sementeira feita sob diferentes praticas culturais: mobilização convencional, mobilização mínima e sementeira direta. Em sementeira direta foram ainda testadas duas velocidades de trabalho, 4 km-1 e 6 km-1. A profundidade de sementeira foi determinada a partir da medição do comprimento do mesocótilo do milho após a emergência da cultura. A média, desvio padrão, coeficiente de variação e correlação dos valores de resistência ao rompimento do solo e profundidade de sementeira foram determinados. Os resultados demonstraram que independentemente da pratica cultural utilizada se verificou uma correlação negativa entre os valores encontrados para a resistência ao rompimento do solo e os valores de profundidade de deposição da semente, sendo o valor mais acentuado na condição de sementeira direta (r = - 0.77) à velocidade de trabalho de 4 km-1. A melhor performance de sementeira foi conseguida em sementeira direta com o aumento de velocidade de trabalho de 4 para 6 km-1 com um coeficiente de variação de 10.1%. A análise de variância demonstrou haverem diferenças significativas nas profundidades de sementeira causadas pela resistência do solo e pela velocidade de trabalho do semeador de sementeira direta

Use of Biochar from Rice Husk Pyrolysis: Part A: Recovery as an Adsorbent in the Removal of Emerging Compounds

[EN] One of the main products of pyrolysis is char. For the better performance and improvement of its physicochemical properties, it is necessary to make temperature changes. In this study, different temperatures have been tested for the pyrolysis of rice husk, and the biochar obtained from the process went through an evaluation to test its yield in the removal of emerging compounds such as azithromycin (AZT) and erythromycin (ERY). For this, pyrolysis of rice husk has been carried out at temperatures of 450, 500, 550, and 600 degrees C, and the biochars have been characterized by ultimate analysis and proximate analysis, as well as specific surface area tests. Then, different adsorption tests have been carried out with a 200 mg L-1 drug (AZT and ERY) solution prepared in the laboratory. All biochars have been found to present removal percentages higher than 95%. Therefore, obtaining biochar from rice husk at any temperature and using it in the removal of high-molecular-weight compounds are quite suitable.This work was carried out with financial support from the Department of Civil and Environmental Engineering at Universidad de los Andes. This publication was partially made possible by the call for proposals CI-0120: "Publish your new knowledge or expose your new creations" from the Office Vice President for Research and Creation at Universidad de los Andes

Escala de Calgary para el diagnóstico del síncope vasovagal. Estudio de pruebas diagnósticas

ResumenObjetivoEvaluar la utilidad de la escala de Calgary en el diagnóstico de síncope vasovagal comparada con los resultados de la prueba de mesa inclinada (Tilt test) bajo protocolo sensibilizado con medicamentos.MetodologíaEstudio prospectivo de pruebas diagnósticas en pacientes con sospecha de síncope vasovagal sometidos a prueba de mesa inclinada (Tilt test) con vasodilatación inducida con nitroglicerina por vía sublingual. Se incluyeron pacientes mayores de 18 años de edad y se excluyeron pacientes con cardiopatía estructural documentada.ResultadosSe analizaron 100 pacientes, promedio de 48,7 años (DE 19,7), 69% de género femenino y 4% residentes en área rural. La mediana de síncopes al momento del Tilt test fue de 5 (RIQ 2-15) con presentación del primer episodio a los 41 años (RIQ 21-57), en el 52% de los pacientes no se identificaron desencadenantes y las manifestaciones clínicas referidas en los episodios previos al Tilt test fueron diaforesis (58%), palidez (55%), mareo (70%), palpitaciones (50%) y náuseas (42%); durante el Tilt test se reportaron mareo (65%), diaforesis (19%), náuseas (18%) y visión borrosa (18%). Se obtuvo una sensibilidad del 77,7% (IC95%: 66,7-88,8) y una especificidad del 40,5% (IC95%: 23,3-57,7) para la escala de Calgary.ConclusionesDebido a su buena sensibilidad y fácil aplicación, la escala de Calgary es un instrumento útil para el abordaje diagnóstico de pacientes con sospecha de síncope vasovagal y corazón estructuralmente sano, especialmente en menores de 50 años de edad.AbstractObjectiveEvaluate the utility of Calgary score for the diagnosis of vasovagal syncope compared with the results of the Tilt table test using sensibilized protocol with medicines.MethodologyProspective study of diagnostic tests in patients with suspected diagnostic of vasovagal syncope who underwent tilt table test with induced vasodilation with sublingual nitroglycerin. Patients over 18 years were included and patients with documented structural heart disease were excluded.Results100 patients were analyzed, averaging 48.7 years of age (SD 19.7), 69% of feminine genre and 4% residents in rural area. Medium of syncope at the moment of tilt table test was 5 (IQR 2-15), with presentation of first episode at 41 years (IQR 21-57), in 52% of the patients triggers were not identified and the clinical manifestations referred in episodes previous to Tilt test were diaphoresis (58%), pallor (55%), dizziness (70%), palpitations (50%) and nausea (42%); during the test dizziness (65%), diaphoresis (19%), nausea (18%) and blurred vision (18%) were reported. A sensitivity of 77.7% was obtained (95% CI 88.8 66.7) and specificity of 40.5% (95% CI 23.3 - 57.7) for the Calgary score.ConclusionsDue to its high sensitivity and easy application, the Calgary score is a useful diagnostic approach instrument for patients with suspected vasovagal syncope and who have a structurally healthy heart, especially in those younger than 50 years

Undergraduate Design Experiences in the TransAtlantic Biosystems Engineering Network (TABE.NET)

Trans-Atlantic Biosystems Engineering Network (TABE.NET) has been established with the overall goal to advance internationalization of Biosystems Engineering (BSEN) curricula and develop a global awareness within the discipline. The participating institutions are Virginia Polytechnic Institute and State University (VT), University of Illinois at Urbana-Champaign (UIUC), University College Dublin (UCD), Agricultural University of Athens (AUA), Universidad Politecnica de Madrid (UPM), and University of Bari (UniBar). A working group is exploring the potential to develop an international collaborative design project for undergraduate students in the participating institutions. This paper summarizes the first step in the process by examining current course structures and design experiences across the network. There is a clear trend towards problem-based learning in real-life type design projects in team environments. There is potential for a collaborative undergraduate design activity across the network but further discussion and analysis is required