47 research outputs found
Some inequalities on generalized entropies
We give several inequalities on generalized entropies involving Tsallis
entropies, using some inequalities obtained by improvements of Young's
inequality. We also give a generalized Han's inequality.Comment: 15 page
Temperature dependence of capture coefficients in trapping phenomena
The temperature dependence of the capture coefficients in trapping phenomena is investigated. It is proved that, besides the dependence induced by the thermal velocity of the carriers, the stress-induced traps at the interfaces of the multi-layered structures present a supplementary temperature dependence. This dependence is found to be of Gaussian type and is in a good agreement with the experimental results. © 2010 IEEE
Stress-induced traps in multilayered structures
The trap parameters of defects in Si/CaF 2 multilayered structures were determined from the analysis of optical charging spectroscopy measurements. Two kinds of maxima were observed. Some of them were rather broad, corresponding to "normal" traps, while the others, very sharp, were attributed to stress-induced traps. A procedure of optimal linear smoothing the noisy experimental data has been developed and applied. This procedure is based on finding the minimal value of the relative error with respect to the value of the smoothing window. In order to obtain a better accuracy for the description of the trapping-detrapping process, a Gaussian temperature dependence of the capture cross-sections characterizing the stress-induced traps was introduced. Both the normal and the stress-induced traps have been characterized, including some previously considered as only noise features. ©2011 American Institute of Physics
Stress-induced traps in multilayered structures
The trap parameters of defects in Si/CaF2 multilayered structures were
determined from the analysis of optical charging spectroscopy measurements. Two
kinds of maxima were observed. Some of them were rather broad, corresponding to
"normal" traps, while the others, very sharp, were attributed to stress-induced
traps. A procedure of optimal linear smoothing the noisy experimental data has
been developed and applied. This procedure is based on finding the minimal
value of the relative error with respect to the value of the smoothing window.
In order to obtain a better accuracy for the description of the
trapping-detrapping process, a Gaussian temperature dependence of the capture
crosssections characterizing the stress-induced traps was introduced. Both the
normal and the stress-induced traps have been characterized, including some
previously considered as only noise features.Comment: 37 pages, 9 figure
Sphingosine 1-phosphate lyase ablation disrupts presynaptic architecture and function via an ubiquitin- proteasome mediated mechanism
The bioactive lipid sphingosine 1-phosphate (S1P) is a degradation product of sphingolipids that are particularly abundant in neurons. We have shown previously that neuronal S1P accumulation is toxic leading to ER-stress and an increase in intracellular calcium. To clarify the neuronal function of S1P, we generated brain-specific knockout mouse models in which S1P-lyase (SPL), the enzyme responsible for irreversible S1P cleavage was inactivated. Constitutive ablation of SPL in the brain (SPL(fl/fl/Nes)) but not postnatal neuronal forebrain-restricted SPL deletion (SPL(fl/fl/CaMK)) caused marked accumulation of S1P. Hence, altered presynaptic architecture including a significant decrease in number and density of synaptic vesicles, decreased expression of several presynaptic proteins, and impaired synaptic short term plasticity were observed in hippocampal neurons from SPL(fl/fl/Nes) mice. Accordingly, these mice displayed cognitive deficits. At the molecular level, an activation of the ubiquitin-proteasome system (UPS) was detected which resulted in a decreased expression of the deubiquitinating enzyme USP14 and several presynaptic proteins. Upon inhibition of proteasomal activity, USP14 levels, expression of presynaptic proteins and synaptic function were restored. These findings identify S1P metabolism as a novel player in modulating synaptic architecture and plasticity
Neutral sphingomyelinase mediates the co-morbidity trias of alcohol abuse, major depression and bone defects
Mental disorders are highly comorbid and occur together with physical diseases, which are often considered to arise from separate pathogenic pathways. We observed in alcohol-dependent patients increased serum activity of neutral sphingomyelinase. A genetic association analysis in 456,693 volunteers found associations of haplotypes of SMPD3 coding for NSM-2 (NSM) with alcohol consumption, but also with affective state, and bone mineralisation. Functional analysis in mice showed that NSM controls alcohol consumption, affective behaviour, and their interaction by regulating hippocampal volume, cortical connectivity, and monoaminergic responses. Furthermore, NSM controlled bone–brain communication by enhancing osteocalcin signalling, which can independently supress alcohol consumption and reduce depressive behaviour. Altogether, we identified a single gene source for multiple pathways originating in the brain and bone, which interlink disorders of a mental–physical co-morbidity trias of alcohol abuse—depression/anxiety—bone disorder. Targeting NSM and osteocalcin signalling may, thus, provide a new systems approach in the treatment of a mental–physical co-morbidity trias
Use of efavirenz for the treatment of lipid storage diseases
The present invention relates to the use of efavirenz for manufacturing a medicament for the treatment of lipid storagediseases such as Niemann-Pick diseases. By activating CYP46, which promotes cholesterol eliminati n in neurons among other lipids, o efavirenz is capable of normalizing the levels of these lipids and neuronal fnnction. Efavirenz can also be used in combination with another active principie considered effective for the treatment of these diseases, to enhance the therapeutic effectsPeer reviewedConsejo Superior de Investigaciones Científicas (España)A1 Solicitud de patente con informe sobre el estado de la técnic
Uso de efavirenz para el tratamiento de enfermedades de almacenamiento lipídico
La presente invención se refiere al uso de efavirenz para fabricar un medicamento para el tratamiento de enfermedades de almacenamiento lipídico tales como enfermedades de Niemann-Pick . Mediante la activación de CYP46, que estimula la eliminación de colesterol en las neuronas , entre otros lípidos ,efavirenz es capaz de normalizar los niveles de estos lípidos y la función neuronal. Efavirenz también se
puede usar en combinación con otro principio activo
considerado eficaz para el tratamiento de estas
enfermedades, para mejorar los efectos terapéuticosPeer reviewedConsejo Superior de Investigaciones Científicas (España)A1 Solicitud de patente con informe sobre el estado de la técnic
Temperature dependence of capture coefficients in trapping phenomena
The temperature dependence of the capture coefficients in trapping phenomena is investigated. It is proved that, besides the dependence induced by the thermal velocity of the carriers, the stress-induced traps at the interfaces of the multi-layered structures present a supplementary temperature dependence. This dependence is found to be of Gaussian type and is in a good agreement with the experimental results. © 2010 IEEE