1,493 research outputs found
Functional anatomy of 5-HT2A receptors in the amygdala and hippocampal complex : relevance to memory functions
The amygdaloid complex and hippocampal region contribute to emotional activities, learning, and memory. Mounting evidence suggests a primary role for serotonin (5-HT) in the physiological basis of memory and its pathogenesis by modulating directly the activity of these two areas and their cross-talk. Indeed, both the amygdala and the hippocampus receive remarkably dense serotoninergic inputs from the dorsal and median raphe nuclei. Anatomical, behavioral and electrophysiological evidence indicates the 5-HT2A receptor as one of the principal postsynaptic targets mediating 5-HT effects. In fact, the 5-HT2A receptor is the most abundant 5-HT receptor expressed in these brain structures and is expressed on both amygdalar and hippocampal pyramidal glutamatergic neurons as well as on γ-aminobutyric acid (GABA)-containing interneurons. 5-HT2A receptors on GABAergic interneurons stimulate GABA release, and thereby have an important role in regulating network activity and neural oscillations in the amygdala and hippocampal region. This review will focus on the distribution and physiological functions of the 5-HT2A receptor in the amygdala and hippocampal region. Taken together the results discussed here suggest that 5-HT2A receptor may be a potential therapeutic target for those disorders related to hippocampal and amygdala dysfunction.peer-reviewe
On the evolution of elastic properties during laboratory stick-slip experiments spanning the transition from slow slip to dynamic rupture
The physical mechanisms governing slow earthquakes remain unknown, as does the
relationship between slow and regular earthquakes. To investigate the mechanism(s) of slow earthquakes
and related quasi-dynamic modes of fault slip we performed laboratory experiments on simulated fault
gouge in the double direct shear configuration. We reproduced the full spectrum of slip behavior, from slow
to fast stick slip, by altering the elastic stiffness of the loading apparatus (k) to match the critical rheologic
stiffness of fault gouge (kc). Our experiments show an evolution from stable sliding, when k>kc, to
quasi-dynamic transients when k ~ kc, to dynamic instabilities when k<kc. To evaluate the microphysical
processes of fault weakening we monitored variations of elastic properties. We find systematic changes in P
wave velocity (Vp) for laboratory seismic cycles. During the coseismic stress drop, seismic velocity drops
abruptly, consistent with observations on natural faults. In the preparatory phase preceding failure, we find
that accelerated fault creep causes a Vp reduction for the complete spectrum of slip behaviors. Our results
suggest that the mechanics of slow and fast ruptures share key features and that they can occur on same
faults, depending on frictional properties. In agreement with seismic surveys on tectonic faults our data show
that their state of stress can be monitored by Vp changes during the seismic cycle. The observed reduction in
Vp during the earthquake preparatory phase suggests that if similar mechanisms are confirmed in nature
high-resolution monitoring of fault zone properties may be a promising avenue for reliable detection of
earthquake precursors
Clinical significance of the buccal fat pad: how to determine the correct surgical indications based on preoperative analysis
Background: Despite the multitude of clinical and aesthetic uses, the correct surgical indications for buccal fat pad
(BFP) removal have yet to be fully elucidated. Although the procedure is widely performed and promoted for
aesthetic purpose, literature lacks of studies accounting for a proper evaluation of patients undergoing BFP removal.
Methods: Between 2012 and 2016 patients seeking an improvement of the malar contour by reduction of the
submalar prominence have been visited at the Department of Plastic Surgery of the Institution. A preoperative MRI
was requested in order to correctly identify the volume of the BFP and the presence of a masseter muscle (MM)
hypertrophy.
Results: According to clinical examination and the results of the preoperative imaging, patients were offered different
treatment options: patients with BFP hypertrophy underwent BFP removal through an itraoral approach; patients with
MM hypertrophy received injection of 50 UI of botulinum toxin (BTX). No complications were observed in the
postoperative period and all patients were satisfied with the results.
Conclusions: According to the experience, midface contouring procedures should take account of both surgeons’
experience, patients’ expectations and anatomical evaluation. As such, there is no given approach suitable for all
cases. Suggested visual criteria, clinical examination and imaging analysis are useful in establishing patient’s
condition and determining the appropriate methods of treatment to enhance the facial profile
Producción de hidrógeno en microreactores mediante reformado con vapor de bioetanol
Actualmente la mayor parte del hidrógeno producido industrialmente procede de
combustibles fósiles, o sea, de fuentes no renovables. En los últimos años se están
estudiando diferentes soluciones para producir hidrógeno y una vÃa prometedora parece el
reformado con vapor de etanol. La peculiaridad del etanol es la posibilidad de ser producido
por vÃa biológica asà que nos permitirÃa cerrar el ciclo de CO2, es decir, el CO2 que se emite
en el proceso de reformado es equivalente al CO2 consumido por la biomasa para mantener
asà invariado el nivel de este gas en la atmósfera.
El presente proyecto estudia un sistema para la producción de hidrógeno a microescala, a
través de un microreactor que lleva en su parte interna un catalizador basado en cobalto
adherido sobre una placa de acero inoxidable 316.
El hidrógeno producido, tras un adecuado proceso de purificación, podrÃa ser utilizado en
una microcelda de combustible para aplicaciones portátiles.
Este trabajo trata la preparación y adhesión del catalizador sobre placas metálicas, el diseño
y montaje del reactor, la elección y puesta a punto de la periferia necesaria para el correcto
funcionamiento del sistema y las pruebas catalÃticas de reformado de etanol con vapor.
A pesar de los bajos tiempos de residencia, el dispositivo alcanza conversiones
prácticamente totales gracias a la elevada área especÃfica de contacto
Producción de hidrógeno en microreactores mediante reformado con vapor de bioetanol
Actualmente la mayor parte del hidrógeno producido industrialmente procede de
combustibles fósiles, o sea, de fuentes no renovables. En los últimos años se están
estudiando diferentes soluciones para producir hidrógeno y una vÃa prometedora parece el
reformado con vapor de etanol. La peculiaridad del etanol es la posibilidad de ser producido
por vÃa biológica asà que nos permitirÃa cerrar el ciclo de CO2, es decir, el CO2 que se emite
en el proceso de reformado es equivalente al CO2 consumido por la biomasa para mantener
asà invariado el nivel de este gas en la atmósfera.
El presente proyecto estudia un sistema para la producción de hidrógeno a microescala, a
través de un microreactor que lleva en su parte interna un catalizador basado en cobalto
adherido sobre una placa de acero inoxidable 316.
El hidrógeno producido, tras un adecuado proceso de purificación, podrÃa ser utilizado en
una microcelda de combustible para aplicaciones portátiles.
Este trabajo trata la preparación y adhesión del catalizador sobre placas metálicas, el diseño
y montaje del reactor, la elección y puesta a punto de la periferia necesaria para el correcto
funcionamiento del sistema y las pruebas catalÃticas de reformado de etanol con vapor.
A pesar de los bajos tiempos de residencia, el dispositivo alcanza conversiones
prácticamente totales gracias a la elevada área especÃfica de contacto
Adrenal pheochromocytoma incidentally discovered in a patient with parkinsonism
To evaluate the diagnostic route of pheochromocytoma (PHEO) in a patient under dopaminergic treatment. A 70-year-old man with Parkinsonism and under treatment with levodopa and carbidopa came to our observation for evaluation of arterial hypertension and right adrenal mass discovered incidentally. To evaluate adrenal hormone levels we performed a dexamethasone suppression test, plasma aldosterone levels and 24-hr urinary metanephrine, which revealed elevated levels of catecholamines metabolities. 123-I-metaiodobenzylguanidine SPECT scintiscan revealed raised activity within the right adrenal gland concordant with the mass. The diagnosis of PHEO was posed and an elective laparoscopic adrenalectomy was performed; histopathological examination confirmed the PHEO diagnosis. Recently the coexistence of PHEO and Parkinsonism is a very rare association of diseases, with only 3 cases reported in literature. In this article, another case is reported and diagnostic procedures are discusse
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