The reliable incorporation of hydrogen as a clean energy source necessitates an in-depth comprehension of the dynamics of flammable clouds resulting from potential leakage incidents. This research ...introduces an innovative model rooted in the principles of the kinetic theory of gases to determine the dimensions of flammable hydrogen clouds during leaks. The model integrates critical variables such as leak rate, leak direction, wind speed, and wind direction, in addition to surrounding atmospheric conditions, offering a precise forecast of hydrogen dispersion and behaviour during leakage scenarios. This modelling approach relies on two dimensionless groups derived through dimensional analysis, and the correlation between these groups has been established. Furthermore, the model incorporates three constants accounting for hydrogen buoyancy, gas dilution, and mixing, which are fine-tuned through a minimal number of Computational Fluid Dynamics (CFD) simulations. This indispensable information is crucial for the formulation of effective safety protocols, evacuation plans, and risk assessment strategies. Validation of the model against simulated data attests to its accuracy and reliability, underscoring its potential as a valuable tool for steering the secure integration of hydrogen technologies. This research significantly contributes to the advancement of safety measures in the utilisation of hydrogen as a clean energy source, providing a robust foundation for the design and implementation of precautionary measures in real-world applications.
•A method for predicting hydrogen flammable cloud size based on dimensional analysis and CFD is proposed.•This method allows an improvement in the calculation efficiency while ensuring its accuracy.•A detailed comparative analysis of three prediction methods was presented in this paper.•This method is suitable for explosion risk analysis during the preliminary design phase.
The retina is a highly specialized tissue, made up of various cell types that are structured and organized to form a complex neural network. However, the retina is also highly susceptible to various ...types of pathophysiological alterations, which can lead to the loss of the different cellular elements and thus to the loss of a large part of the retina's visual functions.
Over time, different types of behavioural, functional or electrophysiological tests have been developed that have allowed us to study the different visual capacities of the retina in murine models of retinal neurodegeneration, without the need to sacrifice the animals or induce serious damage from invasive recording.
Behavioural testing has proven to be a powerful tool for the study of alterations in retinal visual pathways. These techniques allow a simple but effective analysis of the visual capabilities of experimental animal models with retinal degenerative processes. Physiological aspects such as light sensitivity or the degree of visual acuity of these animal models can be quickly and effectively analysed by applying different types of tests such as the Light/Dark Transition Test or the Optomotor Test, respectively. Likewise, behavioural techniques also allow us to study other biological aspects such as the circadian activity of the animal models, which would allow us to study alterations that also affect the retinal pathways that do not participate in the image formation process. In addition, the simplicity of some of these tests allows the combination of several parameters that allow us to simultaneously study several visual abilities equally.
Likewise, other non‐invasive functional tests, such as the Pupillary Light Reflex study, allow us to determine the degree to which retinal neurodegenerative disorders affect other closely related signalling pathways, such as the afferent and efferent pathways responsible for the pupillary reflex.
Finally, electroretinographic recording techniques are an invaluable tool for studying the functionality of the various retinal cell populations. By applying specific light stimuli, it is possible to record the specific response of certain cellular elements, studying how various pathophysiological alterations of the retina affect its functionality. Variations of these techniques have even made it possible to study the activity of cells in the primary visual cortex.
With the development of new fields of study, such as optopharmacology, the knowledge and correct choice of visual characterization techniques is essential to study the efficacy of these new ophthalmological approaches.
En la actualidad del turismo internacional las diversas regiones del planeta se dividen en clústeres de mercado especializados para la atracción del consumo de la experiencia que implica, esto a ...través de la constitución de “marcas-país”. Es en este marco contextual que se realiza el presente análisis del discurso sobre la Responsabilidad Social Empresarial, los Certificados de Sostenibilidad Ambiental y la campaña oficial del Instituto Costarricense de Turismo (ICT) en el año 2012, en los cuáles los estereotipos de la imagen del trópico, del turismo de naturaleza, sol y playa se articulan con el aprovechamiento retórico de la imagen de la población local de Costa Rica como la del “país más feliz del mundo”, hacia el maquillar las contradicciones sociales, laborales, culturales y ecológicas internas, siguiendo mitos sobre el excepcionalismo costarricense. Este proceso refleja una división global del sistema mundo (Wallerstein, 2005), en la cual los centros mundiales conforman “periferias del placer” (Ash y Turner, 1999), donde algunas se encuentran dentro del circuito geográfico tropical del planeta bajo imaginarios de exotismo (Beltrán, 2008) específicos, los cuales podríamos denominar como “tropicalismo”. A la par de esto, siguiendo la lógica del “colonialismo interno” (Amin, 2009), las élites del Estado-Nación de estas regiones tropicales conforman el “auto tropicalismo”, que es el construir la imagen local a semejanza de los deseos de ocio y fantasía que los centros globales conforman.
El Teatro de la Memoria de Valerio Camillo constituye una de las metáforas centrales de Terra Nostra (1975). El teatro es descrito en términos que nos ayudan a comprender tanto el uso que Fuentes ...hace de la historia como el proyecto de utopía textual que propone en su obra. Las imágenes del teatro de Camillo comprenden todas las posibilidades del pasado, no solo aquellas que se cumplieron, sino también aquellas otras que podrían haber sido. La finalidad de esta fantástica maquinaria utópica es la de mostrar una salida al fatalismo de la historia, una alternativa a la repetición de esa "permanente catástrofe" que, según Fuentes, ha sido la historia de Hispanoamérica. El presente artículo busca dar respuesta a una de las grandes interrogantes de la novela: ¿es la utopía totalizante de Fuentes realmente posible o se trata más bien de un espejismo narrativo?
Adrenergic Modulation With Photochromic Ligands Prischich, Davia; Gomila, Alexandre M. J.; Milla‐Navarro, Santiago ...
Angewandte Chemie International Edition,
February 15, 2021, Letnik:
60, Številka:
7
Journal Article
Recenzirano
Odprti dostop
Adrenoceptors are ubiquitous and mediate important autonomic functions as well as modulating arousal, cognition, and pain on a central level. Understanding these physiological processes and their ...underlying neural circuits requires manipulating adrenergic neurotransmission with high spatio‐temporal precision. Here we present a first generation of photochromic ligands (adrenoswitches) obtained via azologization of a class of cyclic amidines related to the known ligand clonidine. Their pharmacology, photochromism, bioavailability, and lack of toxicity allow for broad biological applications, as demonstrated by controlling locomotion in zebrafish and pupillary responses in mice.
Adrenoswitches, a class of novel azoheteroaryl photoswitches, were developed to achieve on‐demand modulation of adrenergic neurotransmission by means of illumination at specific wavelengths. Their versatility to photocontrol biological systems is demonstrated in vivo employing two different animal models, zebrafish and mice.
Background/objectives
Histamine has shown a possible role in the etiopathogenesis of migraine. It has been reported an association between some polymorphisms in the diamine oxidase (DAO) gene and ...migraine, especially in women. Two studies addressing DAO activity in migraine patients showed conflicting results. We investigated the possible relationship of serum DAO activity and histamine levels and 3 polymorphisms in the DAO gene with the risk for migraine.
Methods
We studied the frequencies of DAO rs10156191, rs1049742 and rs1049793 genotypes and allelic variants in 298 migraine patients and 360 healthy controls (using a TaqMan‐based qPCR assay), and serum DAO activity and histamine levels in a subset of 99 migraine patients and 115 controls with strict exclusion criteria, and analysed the relationship of these variables with several clinical features of migraine.
Results
The frequencies of the DAO genotypes and allelic variants analysed were similar in migraine patients and controls. Serum DAO activity was significantly higher in migraine patients (Vmax/Km 4.24 ± 2.93 vs. 3.60 ± 7.64, p < 0.001), especially in females (Vmax/Km 4.63 ± 2.96 vs. 3.18 ± 2.32, p < 0.0001), while serum histamine was similar in both study groups.
Conclusion
Serum DAO activity was increased in patients with migraine, especially in females, while serum histamine levels were normal. None of the studied polymorphisms was associated with the risk for migraine.
Abstract
The implementation rate of renewable energy sources such as lithium‐ion batteries has grown over the last decade. Consequently, the number of explosion occurrences associated with these ...batteries has also increased. Such events are due to a process called thermal runaway (TR). The flamelet combustion approach has been widely used to model premixed combustion. However, its applicability for modelling accidental explosions from lithium‐ion batteries remains limited. Moreover, the effects and contributions from stress, strain, and wrinkling on the flame front in gas mixtures from Li‐ion batteries are not fully understood. As far as computational modelling is concerned, the same effects require further investigation. The current research investigates the performance of the flamelet approach for modelling premixed combustion scenarios caused by the gases ejected by a fully charged lithium‐ion‐phosphate (LFP) battery. A new laminar burning velocity correlation is proposed based on experimental data to calculate overpressure, flame position, and flame velocity in a semi‐confined geometry. Promising results are presented resorted by good agreement with experimental data.
High body mass index (BMI) is associated with neurocognitive impairments that contribute to overeating and interfere with weight loss efforts. Overweight and obesity at midlife can accelerate ...neurodegenerative changes and increase the risk of late-life dementia. Noninvasive neuromodulation represents a novel, affordable and scalable approach to improve neurocognitive function in this context. The purpose of this proof-of-concept study was to examine whether transcranial direct current stimulation (tDCS) aimed at enhancing prefrontal cortex activity could enhance weight loss, in combination with a hypocaloric diet, and study underlying mechanisms.
Overall, 38 women with BMI 25-35 kg/m
underwent a 4 week randomized, double-blinded, sham-controlled, and parallel-design intervention, during which they received eight sessions of tDCS (n = 18 sham, n = 20 active) in combination with a diet (caloric goal of 20 kcal/kg/day). We evaluated longitudinal changes in body weight, appetite and food craving. In addition, we examined the contribution of cognitive-executive processes via food-modified computerized tasks.
We found that the active group had more reduction in body weight than the sham group throughout the study (p = 0.020) and significant weekly weight loss. At 4 weeks, the active group lost 2.32% of initial body weight (sham: 1.29%). Components of subjective appetite and food craving showed a trend toward more reduction in the active group. These changes were paralleled by significant improvements in task performance in the active group, particularly in a dual task that required inhibitory control and working memory (p = 0.007-0.031). Improvement in inhibitory control performance predicted reduction in lack of control overeating, explaining 43.5% of its variance at the end of the study (p = 0.003). No significant adverse effects were observed.
Our results provide proof-of-concept validation of prefrontal-targeted tDCS, combined with a diet, in midlife women with excess body weight, paving the way for larger studies evaluating clinical efficacy and long-term effects of this intervention.
The Spanish presence in Micronesia islands continued after the sale to Germany in 1899. Following Great War, Spaniards Jesuits were sent as missionaries to Caroline Islands. The work was entrusted to ...Betica Province in 1925. They remained there during World War II. Besides, in order to provide with donations and for the promotion of El Angel de Carolinas that work was published. We use this paper to rebuild the war experience of these missionaries in those islands and as a proof that their perceptions were different from those of the official propaganda of Franco’s regime about contenders in World War II.
La presencia española en las islas de la Micronesia no terminó con la venta a Alemania tras el Desastre de 1898. Tras la I Guerra Mundial, los jesuitas españoles fueron enviados como misioneros a las Carolinas, encomendándose la misión a la recién creada provincia Bética en 1925. Allí permanecieron durante la II Guerra Mundial. Para promover los donativos a la obra y hacer propaganda fue creada la revista El Ángel de Carolinas. A través de sus páginas puede reconstruirse la experiencia de la guerra en aquella multitud de islas y cómo el relato transmitido por los misioneros y difundido por la revista se distanciaba de las categorías políticas proyectadas por el régimen de Franco.
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