Comparative analysis of different methods of modeling the thermal effect of circulating blood flow during RF cardiac ablation

Our aim was to compare the different methods of modeling the effect of circulating blood flow on the thermal lesion dimensions created by radio frequency (RF) cardiac ablation and on the maximum blood temperature. Computational models were built to study the temperature distributions and lesion dimensions created by a nonirrigated electrode by two RF energy delivery protocols (constant voltage and constant temperature) under high and low blood flow conditions. Four methods of modeling the effect of circulating blood flowon lesion dimensions and temperature distribution were compared. Three of them considered convective coefficients at the electrode-blood and tissue-blood interfaces to model blood flow: 1) without including blood as a part of the domain; 2) constant electrical conductivity of blood; and 3) temperaturedependent electrical conductivity of blood (+2%/°C). Method 4) included blood motion andwas considered to be a reference method for comparison purposes. Only Method 4 provided a realistic blood temperature distribution.The other three methods predicted lesion depth values similar to those of the reference method (differences smaller than 1 mm), regardless of ablation mode and blood flow conditions. Considering the aspects of lesion size and maximum temperature reached in blood and tissue, Method 2 seems to be the most suitable alternative to Method 4 in order to reduce the computational complexity. Our findings could have an important implication in future studies of RF cardiac ablation, in particular, in choosing the most suitable method to model the thermal effect of circulating blood

Targeting RANKL in metastasis

Acting through its cognate receptor, receptor activator of nuclear factor-κB (RANK), RANK ligand (RANKL) is an essential mediator of osteoclast function and survival. Preclinical data have now firmly established that blockade of tumor-induced osteoclastogenesis by RANKL inhibition will not only protect against bone destruction but will also inhibit the progression of established bone metastases and delay the formation of de novo bone metastases in cancer models. In patients with bone metastases, skeletal complications are driven by increased osteoclastic activity and may result in pathological fractures, spinal cord compression and the need for radiotherapy to the bone or orthopedic surgery (collectively known as skeletal-related events (SREs)). Denosumab, a fully human monoclonal antibody against RANKL, has been demonstrated to prevent or delay SREs in patients with solid tumors that have metastasized to bone. In addition to its central role in tumor-induced osteolysis, bone destruction and skeletal tumor progression, there is emerging evidence for direct pro-metastatic effects of RANKL, independent of osteoclasts. For example, RANKL also stimulates metastasis via activity on RANK-expressing cancer cells, resulting in increased invasion and migration. Pharmacological inhibition of RANKL may also reduce bone and lung metastasis through blockade of the direct action of RANKL on metastatic cells. This review describes these distinct but potentially overlapping mechanisms by which RANKL may promote metastases

Development of phonological and orthographic processing in teenagers with and without reading disabilities

El objetivo de este estudio ha sido analizar el desarrollo del procesamiento fonológico y ortográfico en la lectura en adolescentes normolectores y adolescentes con dificultades de aprendizaje en la lectura. Para analizar el rendimiento de los alumnos se utilizó la Batería Multimedia Sicole-R- ESO (www.ocideidi.net), que evalúa los procesos cognitivos asociados a las DEAL. La herramienta tiene un formato altamente modular, de forma que las tareas de evaluación se agrupan en cinco módulos. Para poder llevar a cabo este estudio se administró el módulo de procesamiento fonológico que evalúa la conciencia fonológica. Este módulo consta de cuatro subtareas: aislar, omitir, síntesis y segmentar. También se administró el módulo de procesamiento ortográfico que consta de dos subtareas, la comprensión de homófonos y la comprensión de pseudohomófonos. Se seleccionó una muestra de adolescentes con dislexia de una población de 945 alumnos de Educación Secundaria Obligatoria (12-16 años) de institutos públicos y privados de las Islas Canarias. Los resultados demostraron que los disléxicos en todos los cursos de la Educación Secundaria Obligatoria se diferencian respecto a los normolectores de su misma edad, tanto en el procesamiento fonológico como en el ortográfico. Este resultado nos indica, que a la hora de diagnosticar las DEAL, debemos evaluar el perfil cognitivo del alumno, estableciendo con precisión dónde reside la dificultad, y no sólo centrarnos en la competencia curricular o en un diagnóstico general de nivel lector. En este sentido, la Batería Multimedia Sicole-R-ESO lleva a cabo un registro exhaustivo del funcionamiento de todos los procesos cognitivos implicados en la lectura, para localizar concretamente donde se presenta la dificultad, permitiéndonos obtener respuestas significativas para comprender ese problema y articular posibles soluciones, adaptadas siempre a las necesidades individuales de los alumnos.The aim of this study was to analyze the development of phonological and orthographic processing in reading in teenagers with and without DEAL using a cross-sectional design. To analyze the performance of the teenagers the Sicole-R-ESO Multimedia Battery (www.ocideidi.net) was used, measuring different cognitive processes associated to reading disabilities. The battery has a highly modular format, so that the assessment tasks are grouped into five modules. To carry out this study phonological processing module that assesses phonological awareness was administered. This module consists of four subtasks: blending, isolation, segmentation, and deletion. Orthographic processing module which consists of two subtasks, homophone and pseudohomophone comprehension subtask were also administered. A sample of teenagers with dyslexia was selected from a population of 945 secundary school students (12-16 years old) from different public and private schools in the Canary Islands. Significant differences were found between dyslexics and normally achieving readers across grades in both, phonological and orthographic processing involved in reading acquisition. This result indicates that when diagnosing DEAL, we must assess the student’s cognitive profile, establishing precisely where the difficulty lies, not just focus on curricular competition or a general diagnosis of reading level. In this sense, the Sicole-R-ESO Multimedia Battery carries out an exhaustive record the performance of all cognitive processes involved in reading, to locate precisely where the difficulty is, allowing to obtain significant information to understand the problem and provide possible solutions to articulate answers, adapted to the individual needs of students.peerReviewe

Avances en la obtención de tableros de fibras a partir de mezclas de residuales lignocelulósicos de bagazo

El pretratamiento del bagazo resulta fundamental en el fraccionamiento de la biomasa en sus componentes principales: celulosa, hemicelulosa y lignina, en la reducción de la cristalinidad de la celulosa y en el aumento del área superficial accesible. El trabajo tiene como objetivo la obtención preliminar de tableros de fibras a partir de la utilización de mezclas de bagazo con residuales lignocelulósicos obtenidos en las etapas de pretratamiento del bagazo (hidrólisis ácida y enzimática). Se realiza un diseño de experimento de mezclas, enrejado simplex de Scheffe utilizando una prensa de calentamiento. Se caracterizan los residuales celulósicos utilizando la técnica analítica Pulsy se evalúa la resistencia a la flexión de los tableros de fibras obtenidos. Los resultados favorecen a la utilización de mezclas de bagazo y sólido de la hidrólisis enzimática para la obtención de los tableros. Como conclusión, se propone continuar con el estudio de mezclas con adición de aglutinante y/o resina de manera que favorezcan las propiedades mecánicas de los tableros.

A computational model of open-irrigated electrode for endocardial RF catheter ablation

Radiofrequency catheter ablation (RFCA) is an important curative treatment for cardiac arrhythmias. However, during RFCA thrombus formation can occur when the electrode-tissue interface temperature exceeds 80°C. Open-irrigated electrodes reduce the risk of such side-effect. No computational model of an open-irrigated electrode in endocardial RFCA accounting for both the saline irrigation flow and the blood motion in the cardiac chamber has been proposed yet. Our aim was to introduce the first computer model including both effects. The model has been validated against existing experimental results. Computational results showed that the surface lesion width and blood temperature are affected by the irrigation flow rate. Smaller surface lesion widths and blood temperatures are obtained with higher irrigation flow rate, while the lesion depth is not affected by changing the irrigation flow rate. Larger lesions are obtained when electrode is placed horizontally. Overall, the computational findings are in close agreement with previous experimental results

Soil and water pollution in a banana production region in tropical Mexico

The effects of abundant Mancozeb (Mn, Zn— bisdithiocarbamate) applications (2.5 kg ha-1week-1 for 10 years) on soil and surface-, subsurface- and groundwater pollution were monitored in a banana production region of tropical Mexico. In soils, severe manganese accumulation was observed, wheras the main metabolite ethylenethiourea was near the detection limit. Surface and subsurface water was highly polluted with ethylenethiourea, the main metabolite of Mancozeb (22.5 and 4.3 lg L-1, respectively), but not with manganese. In deep ground water, no ethylenethiourea was detected. The level of pollution in the region presents a worrisome risk for aquatic life and for human health

CNO behaviour in planet-harbouring stars. II. Carbon abundances in stars with and without planets using the CH band

Context. Carbon, oxygen and nitrogen (CNO) are key elements in stellar formation and evolution, and their abundances should also have a significant impact on planetary formation and evolution. Aims. We present a detailed spectroscopic analysis of 1110 solar-type stars, 143 of which are known to have planetary companions. We have determined the carbon abundances of these stars and investigate a possible connection between C and the presence of planetary companions. Methods. We used the HARPS spectrograph to obtain high-resolution optical spectra of our targets. Spectral synthesis of the CH band at 4300\AA was performed with the spectral synthesis codes MOOG and FITTING. Results. We have studied carbon in several reliable spectral windows and have obtained abundances and distributions that show that planet host stars are carbon rich when compared to single stars, a signature caused by the known metal-rich nature of stars with planets. We find no different behaviour when separating the stars by the mass of the planetary companion. Conclusions. We conclude that reliable carbon abundances can be derived for solar-type stars from the CH band at 4300\AA. We confirm two different slope trends for [C/Fe] with [Fe/H] because the behaviour is opposite for stars above and below solar values. We observe a flat distribution of the [C/Fe] ratio for all planetary masses, a finding that apparently excludes any clear connection between the [C/Fe] abundance ratio and planetary mass.Comment: 10 pages, 10 figures. Accepted to A&

Computational Model for Prediction of the Occurrence of Steam Pops during Irrigated Radiofrequency Catheter Ablation

Radiofrequency catheter ablation (RFCA) is a curative treatment for cardiac arrhythmias. Although globally a pretty safe procedure, it may present some risk. Steam pop is a serious complication that can occur during RFCA with irrigated electrodes. Pops are caused by tissue overheating above 89oC, and may cause explosive rupture of myocardial wall. Today, it is still very complicated to predict the occurrence and location of steam pops into the tissue during RFCA. Our aim was to use a computational model to address these issues considering two irrigated catheter tip designs and different power settings. The model has been validated against existing experimental results. Computational results show no evidence of significant differences in the incidence of steam pops between the two catheter designs. Steam pops appears at powers higher than 30W at approximately 2 mm depth under the electrode tip. Overall, the computational findings were in close agreement with previous experimental results, which suggests that the proposed model could be useful to predict the occurrence of steam pops in different clinical situations.MINECO TEC2014–52383-C3-R to E.B. and Generalitat Valenciana APOSTD/2016/045 to A.G.S