101 research outputs found
Sensitivity and spatial selectivity of transverse field RF surface coils: A theoretical and experimental study at 2.35T
A number of clinical magnetic resonance imaging/spectroscopy applications require a careful selection of the radiofrequency (RF) coil design to optimize
the coil sensitivity and spatial selectivity in a well-defined region of interest. Small surface receiver RF coils are often used because they are highly sensitive, easy to construct, and provide spatial signal localization. We have analysed axial (square loop, SL) and transverse (figure-of-eight, FO8; butterfly, BC) RF field surface coils to study sensitivity and spatial selectivity along the coil axis. We have performed simulations with a finite element method at 100MHz, and built prototypes of the coils. GE images were acquired in the presence of an oil phantom using a 2.35T
Bruker animal scanner. The results show a higher sensitivity and a more pronounced spatial selectivity along the coil axis with the transverse coils, as compared to the
standard SL in the proximity of the RF coil plane. Moreover, a transmit flip angle calibration has been performed and a pronounced gain is obtained with the transverse coils. These features should be useful to optimize the RF coil sensitivity and spatial selectivity in a specific region of interest along the coil axis
Teatro Alfonsetti [Material gráfico]: dará tres funciones los dĂas 9, 10 y 11
Representaciones: El infierno ; La tonta del bote ; CancioneraCopia digital. Valladolid : Junta de Castilla y LeĂłn. ConsejerĂa de Cultura y Turismo, 2012-201
Teatro Alfonsetti [Material gráfico]: CompañĂa CĂłmico-Dramática Alejo Casal : acontecimiento teatral hoy sábado 13 de junio de 1925
Representaciones: El orgullo de AlbaceteCopia digital. Valladolid : Junta de Castilla y LeĂłn. ConsejerĂa de Cultura y Turismo, 2012-201
Are We What We Eat? Impact of Diet on the Gut-Brain Axis in Parkinson's Disease
Parkinson’s disease is characterized by motor and non-motor symptoms, such as defects in the gut function, which may occur before the motor symptoms. To date, there are therapies that can improve these symptoms, but there is no cure to avoid the development or exacerbation of this disorder. Dysbiosis of gut microbiota could have a crucial role in the gut–brain axis, which is a bidirectional communication between the central nervous system and the enteric nervous system. Diet can affect the microbiota composition, impacting gut–brain axis functionality. Gut microbiome restoration through probiotics, prebiotics, synbiotics or other dietary means could have the potential to slow PD progression. In this review, we will discuss the influence of diet on the bidirectional communication between gut and brain, thus supporting the hypothesis that this disorder could begin in the gut. We also focus on how food-based therapies might then have an influence on PD and could ameliorate non-motor as well as motor symptoms
The Influence of Dietary Supplementations on Neuropathic Pain
Neuropathic pain is defined as pain caused by a lesion or disease of the somatosensory nervous system and affects 7–10% of the worldwide population. Neuropathic pain can be induced by the use of drugs, including taxanes, thus triggering chemotherapy-induced neuropathic pain or as consequence of metabolic disorders such as diabetes. Neuropathic pain is most often a chronic condition, and can be associated with anxiety and depression; thus, it negatively impacts quality of life. Several pharmacologic approaches exist; however, they can lead numerous adverse effects. From this perspective, the use of nutraceuticals and diet supplements can be helpful in relieve neuropathic pain and related symptoms. In this review, we discuss how diet can radically affect peripheral neuropathy, and we focus on the potential approaches to ameliorate this condition, such as the use of numerous nutritional supplements or probiotics
Validation of numerical approaches for electromagnetic characterization of magnetic resonance radiofrequency coils
Numerical methods based on solutions of Maxwell's equations are usually adopted for the electromagnetic characterization of Magnetic Resonance (MR) Radiofrequency (RF) coils. In this context, many different numerical methods can be employed, including time domain methods, e.g., the Finite-Difference Time-Domain (FDTD), and frequency domain methods, e.g., the Finite Element Methods (FEM) and the Method of Moments (MoM). We provide a quantitative comparison of performances and a detailed evaluation of advantages and limitations of the aforementioned methods in the context of RF coil design for MR applications. Specifically, we analyzed three RF coils which are representative of current geometries for clinical applications: a 1.5 T proton surface coil; a 7T dual tuned surface coil; a 7T proton volume coil. The numerical simulation results have been compared with measurements, with excellent agreement in almost every case. However, the three methods differ in terms of required computing resources (memory and simulation time) as well as their ability to handle a realistic phantom model. For this reason, this work could provide "a guide to select the most suitable method for each specific research and clinical applications at low and high field"
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