1,983 research outputs found
The Level of NMDA Receptor in the Membrane Modulates Amyloid-β Association and Perforation
Alzheimer’s disease is a neurodegenerative disorder that affects mostly the elderly. The main histopathological markers are the senile plaques formed by amyloid-β peptide (Aβ) aggregates that can perforate the plasma membrane of cells, increasing the intracellular calcium levels and releasing synaptic vesicles that finally lead to a delayed synaptic failure. Several membrane proteins and lipids interact with Aβ affecting its toxicity in neurons. Here, we focus on NMDA receptors (NMDARs) as proteins that could be modulating the association and neurotoxic perforation induced by Aβ on the plasma membrane. In fact, our results showed that decreasing NMDARs, using enzymatic or siRNA approaches, increased the association of Aβ to the neurons. Furthermore, overexpression of NMDARs also resulted in an enhanced association between NMDA and Aβ. Functionally, the reduction in membrane NMDARs augmented the process of membrane perforation. On the other hand, overexpressing NMDARs had a protective effect because Aβ was now unable to cause membrane perforation, suggesting a complex relationship between Aβ and NMDARs. Because previous studies have recognized that Aβ oligomers are able to increase membrane permeability and produce amyloid pores, the present study supports the conclusion that NMDARs play a critical protective role on Aβ actions in hippocampal neurons. These results could explain the lack of correlation between brain Aβ burden and clinically observed dementia
Optimal extensions of compactness properties for operators on Banach function spaces
[EN] Compactness type properties for operators acting in Banach function spaces are not always preserved when the operator is extended to a bigger space. Moreover, it is known that there exists a maximal (weakly) compact linear extension of a (weakly) compact operator if and only if its maximal continuous linear extension to its optimal domain is (weakly) compact. We show that the same happens if we consider AM-compactness for the operator, and we give some partial results regarding Dunford-Pettis operators. Narrow operators-considered as a family defined by a weak compactness type property-are also analyzed from this point of view. Finally, we provide some applications of the fact that an operator from a Banach function space extends to a narrow operator if and only if it is narrow. (C) 2015 Elsevier B.V. All rights reserved.J.M. Calabuig and M.A. Juan were supported by Ministerio de Economía y Competitividad (Spain) (project MTM2011-23164). E. Jiménez Fernández was supported by Junta de Andalucía and FEDER grant P09-FQM-4911 (Spain). E. Jiménez Fernández and E.A. Sánchez-Pérez were supported by Ministerio de Economía y Competitividad (Spain) (project MTM2012-36740-C02-02).Calabuig, JM.; Jiménez Fernández, E.; Juan Blanco, MA.; Sánchez Pérez, EA. (2016). Optimal extensions of compactness properties for operators on Banach function spaces. Topology and its Applications. 203:57-66. https://doi.org/10.1016/j.topol.2015.12.075S576620
Analysis of high concentrator photovoltaic modules in outdoor conditions: Influence of direct normal irradiance, air temperature, and air mass
The study of high concentrator photovoltaic (HCPV) technology under real
conditions is essential to understand its real behavior. The influence of direct
normal irradiance (DNI), air temperature (Tair), and air mass (AM) on the
maximum power of two HCPV modules was studied for more than three years.
Results found are presented in this paper. As expected, the main influence on the
maximum power is DNI. Also, Tair has been found to have small influence on the
maximum power. Regarding AM, two different behaviors have been found. The
maximum power could be considered independent of AM for AM 2, while it
decreases with an approximate linear behavior for AM > 2. Also, the maximum
power of a HCPV module could be estimated with a linear mathematical fitting
based on DNI, Tair, and AMThis work is a part of the project “SIGMPLANTAS: La innovacion en las plantas y modelos de
sistemas de Concentracion Fotovoltaica en España,” IPT-2011-1468-920000 supported by the
Spanish Science and Innovation Ministry and by the European Regional Development Fund/Fondo
Europeo de Desarrollo Regional (ERDF/FEDER)S
Enchondroma versus Low-Grade Chondrosarcoma in Appendicular Skeleton: Clinical and Radiological Criteria
Objectives. To determine the validity of clinical and radiological features of enchondroma and low grade chondrosarcoma, and contrast the biopsy results with the clinical diagnosis based on the history and imaging. Material and Method. The study included 96 patients with cartilage type lesions suggestive of an enchondroma (E) or an low grade chondrosarcoma (LGC) according to the clinical and imaging data. The hypotheses were contrasted with the biopsy. Results. Of the 82 patients studied completely, 56 were considered E (68.29%), 8 as LGC (8.33%) and in 18 (18.75%) were doubtful cases and considered as suspected LGC. Of these, the biopsy showed 4 E (25%), 10 LGC (50%) and 4 were not definitive. On the other hand, of the 56 cases diagnosed as E, 15 were biopsied, 5 of these biopsies turned out to be LGC (33.3%). The 8 cases diagnosed as LGC, were also biopsied and only 4 biopsies (50%) confirmed the initial diagnosis. Features analyzed in the study showed no statistically significant difference. Correlation analysis between the diagnosis issued initially and the biopsy result gave a value of 0.69 (kappa coefficient), which was considered a good correlation. Conclusion. Features analyzed did not have any statistical significance. However, there was a good correlation between initial diagnosis and biopsy's result
Neo-Suprahepatic cava: A case report of a modified technique for domino liver transplantation
Domino liver transplantation, introduced in 1997, originally consisted of a graft from a patient with familial amyloidotic polyneuropathy used as a donor for a compatible recipient, thus increasing the pool of hepatic grafts for liver transplantation. The aim of this report was to present a modification on the technique for outflow reconstruction in domino liver transplantation first proposed by Liu et al and Cescon et al. In this description we proposed a new technique that differs from the one mentioned above by performing a neo-suprahepatic cava, constructed using only an iliac vein graft, facilitating the anastomosis as if it was a regular cadaveric liver transplant.Fil: Padín, J. M.. Fundación Favaloro; ArgentinaFil: Pfaffen, G.. Fundación Favaloro; ArgentinaFil: Pérez Fernández, I.. Fundación Favaloro; ArgentinaFil: Sandi, M.. Fundación Favaloro; ArgentinaFil: Ramisch, D.. Fundación Favaloro; ArgentinaFil: Barros Schelotto, P.. Fundación Favaloro; ArgentinaFil: Gondolesi, Gabriel Eduardo. Fundación Favaloro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
Electrosynthesis of 2,3-butanediol and methyl ethyl ketone from acetoin in flow cells
Acetoin could shortly become a platform molecule due to current progress in fermentation technology, the megatrend for
shifting from an oil-based economy to one based on biomass, the quest for green manufacturing processes and its two
highly reactive carbonyl and hydroxyl moieties. In this paper, the successful electro-conversion of acetoin into two
valuable chemicals, 2,3-butandiol (2,3-BD) and methyl ethyl ketone (MEK), at constant electrical current in aqueous
phase at room temperature using both divided and undivided 20 cm2 filter-press flow cells under experimental conditions
suitable for industrial production is reported. Cathode material is the key parameter to drive the electroreduction towards
one or another chemical. 2,3-BD is the major chemical produced by electrohydrogenation when low hydrogen overvoltage
cathodes, such as Pt and Ni, of high surface area obtained by PVD coating on a carbon gas diffusion layer are used, while
MEK is the principal product produced by electrohydrogenolysis when high hydrogen overvoltage cathodes, such as
graphite, Pb and Cd foils, are employed. 2,3-BD and MEK can be obtained, respectively, in 92.8% and 85.7%
selectivities, 71.7% and 80.4% current efficiencies, with 1.21 and 1.08 kg.h-1.m-2 productivities and power consumptions
of 2.94 and 4.1 kWh.kg-1 using undivided cells and aqueous K2HPO4 electrolysis media at pHs of 3.6 and 5.5. The
reported electroconversion of acetoin is highly flexible because 2,3-BD and MEK can be produced by changing just the
cathode but using the same cell, with the same electrolyte at the same current density
Experimental and theoretical evidence of the first Au(I)Bi(III) interaction
3 pages, 3 figures, 1 scheme.-- Published as an advance article on the web 15th Nov. 2006.Complex [Au(C6F5)2][Bi(C6H4CH2NMe2-2)2] 1 displays the first example of an interaction between Au(I) and Bi(III), the nature of which is shown to be consistent with the presence of a high ionic contribution (79%) and a dispersion type (van der Waals) interaction (21%).The D.G.I.(MEC)/FEDER (CTQ2004-05495) project is
acknowledged. M. Monge thanks the MEC-UR for his contract
‘‘Ramón y Cajal’’. EC through the Socrates/Erasmus program (M.
Nema) and a NATO research fellowship (C. Silvestru) are also
acknowledged.Peer reviewe
A Smart Phone-based Personal Area Network for Remote Monitoring of Biosignals
This paper presents a system whose purpose is
to monitor a patient continuously from indoor or outdoor
environments. The system is based on a Bluetooth PAN, carried
by the patient, whose central node, a smart phone, compiles
information about patient’s location and health status.
These data are encrypted to be sent to a server through Wifi or
GPRS/UMTS. The system provides facilities to access to patient’s
data, even from a smart phone by a J2ME application.
It also allows to configure remotely the threshold values used
to detect emergency situations.Ministerio de Eduación y Ciencia TEC2006-12211-C02-01/TCMMinisterio de Educación y Ciencia TIC2003- 07953-C02-0
Consejos útiles para la presentación del trabajo de terminación de la especialización (TTE).
La presentación y defensa del trabajo de terminación de la especialización (TTE) es uno de los elementos que componen el examen estatal de la especialidad y constituye además, una actividad académica que fortalece la identidad cultural de la institución docente y la capacidad del autor de defender los resultados de su trabajo. Existen dificultades en ambas direcciones. En el presente artículo se ofrecen algunos consejos prácticos y otros elementos importantes a tener en cuenta en la presentación y en el acto de defensa del TTE, haciendo énfasis en los tres componentes principales de ese momento: el tribunal evaluador, el residente y el informe de la investigación.</span
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