The echocardiography diagnosis of cor pulmonale in a horse

The authors describe the two-dimensional and Doppler signs that characterize the pulmonary hypertension caused by chronic obstructive pulmonary disease (COPD) in a horse

Predicción de fenómenos arrítmicos a través de la variabilidad de la frecuencia cardíaca en caninos

El estudio de la variabilidad de la frecuencia cardíaca (VFC) es una de las técnicas que permiten conocer el balance y efecto de ambas divisiones del sistema nervioso autónomo sobre el corazón del ser humano. El predominio simpático predispone a las arritmias cardíacas. El estudio consiste en realizar una exploración electrocardiográfica ambulatoria (Holter) y compilar las variaciones que se producen en el intervalo RR entre cada latido cardíaco. De acuerdo a los datos obtenidos tras el correspondiente procesamiento estadístico se desprende que en el perro portador de enfermedades cardíacas la VFC dis­minuye tal como acontece en el ser humano y, por lo tanto, cumpliría la misma función como predictor de sucesos arrítmicos

Flujos atrioventriculares normales evaluados por la técnica Doppler espectral en caninos

Los autores realizaron un estudio de las posiciones más adecuadas para estudiar los flujos transmitral y transtricuspídeo por medio de Doppler espectral pulsado en caninos normales y determinar los valores medios de los siguientes parámetros: velocidad pico, velocidad media, gradiente pico de presión, gradiente medio de presión, integral tiempo–velocidad y relación entre ondas E y A. Las mejores posiciones para la obtención de valores del flujo mitral y tricuspídeo fueron la imagen apical de cinco cámaras captada desde la ventana paraesternal izquierda para la primera y la oblicua del tracto de entrada ventricular derecho en la misma ventana para la segunda

Rapid methods to detect organic mercury and total selenium in biological samples

<p>Abstract</p> <p>Background</p> <p>Organic mercury (Hg) is a global pollutant of concern and selenium is believed to afford protection against mercury risk though few approaches exist to rapidly assess both chemicals in biological samples. Here, micro-scale and rapid methods to detect organic mercury (< 1.5 ml total sample volume, < 1.5 hour) and total selenium (Se; < 3.0 ml total volume, < 3 hour) from a range of biological samples (10-50 mg) are described.</p> <p>Results</p> <p>For organic Hg, samples are digested using Tris-HCl buffer (with sequential additions of protease, NaOH, cysteine, CuSO₄, acidic NaBr) followed by extraction with toluene and Na₂S₂O₃. The final product is analyzed via commercially available direct/total mercury analyzers. For Se, a fluorometric assay has been developed for microplate readers that involves digestion (HNO₃-HClO₄and HCl), conjugation (2,3-diaminonaphthalene), and cyclohexane extraction. Recovery of organic Hg (86-107%) and Se (85-121%) were determined through use of Standard Reference Materials and lemon shark kidney tissues.</p> <p>Conclusions</p> <p>The approaches outlined provide an easy, rapid, reproducible, and cost-effective platform for monitoring organic Hg and total Se in biological samples. Owing to the importance of organic Hg and Se in the pathophysiology of Hg, integration of such methods into established research monitoring efforts (that largely focus on screening total Hg only) will help increase understanding of Hg's true risks.</p

Geometry Affected Delamination of Polymer/Metal Metamaterials

At present several material combinations are fabricated to cover the demands of ubiquitous applications. In the case of meta materials, properties are greatly affected not only by composition and shape, but also by interfacial strength and directionality of the patterned substructure. In this work a bottom-up approach is chosen to characterize interface strength, where interfacial interaction is calculated using atomistic models and is translated into a Traction Separation Law (TSL) for interfaces between continua. Subsequently, this is used to study the influence of interfaces on the effective mechanical response of a variety of metamaterials containing copper/epoxy interfaces. This electronic document is a "live" template and already defines the components of your paper Ititle, text, heads, etc.1 in its style sheet

Monitoring acid-volatile sulphide by a fast scan voltammetric method: application to mercury contamination studies in salt marsh sediments

The present work demonstrates the application of fast scan linear sweep cathodic stripping voltammetry to the determination of acid-volatile sulphide (AVS) in salt marsh sediments. This approach combines very fast analysis with relatively high sensitivity without the need for additional reagents or derivatization procedures. The purge-and-trap AVS methodology was used. The sulphide content in the trapping NaOH solution was directly measured by voltammetry with a high scan rate (1000 mV s−1). The limit of detection (3σ) was 0.34 μmol L−1 for a deposition time of 5 s. Vertical distribution of AVS in sediments was determined in salt marsh sediments of a Portuguese coastal lagoon vegetated with H. portulacoides and correlated to the total dissolved mercury content in pore waters. At the depth of higher root biomass (around 20 cm), AVS concentrations (range 0.24–24.8 μmol g−1) were low in comparison to other depths, probably due to modifications in sediments that occur in the vicinity of the roots. The highest dissolved mercury concentrations (835 and 675 ng L−1), were found at the surface layer and at 20 cm depth, with an opposite trend from that of AVS. A possible explanation is that root activity reduced AVS concentrations at the depth of higher root biomass and resulted in elevated pore water concentrations of mercury. Concentrations of mercury in pore water from layers above and below the high root biomass were consistently lower (less than 152 ng L−1)

Mercury partition in the interface between a contaminated lagoon and the ocean: the role of particulate load and composition

After having estimated the patterns of flow to the ocean and found some seasonal and tidal differences, mainly with regard to the relative importance of dissolved and particulate fractions, mercury partitioning at the interface between a contaminated lagoon and the Atlantic Ocean was investigated during four tidal cycles in contrasting season and tidal regimes. Mercury was found to be located predominantely in the particulate fraction throughout the year, contributing to its retention within the system. Seasonal conditions, variations in marine and fluvial signals and processes affecting bed sediment resuspension influenced the character and concentration of suspended particulate matter in the water column. Variation in the nature, levels and partitioning of organic carbon in the particulate fraction affected levels of particulate mercury as well as mercury partitioning. These results highlight the dominant role of suspended particulate matter in the distribution of anthropogenic mercury and reinforce the importance of competitive behavior related to organic carbon in mercury scavenging