8,778 research outputs found
Extended Optical Model Analyses of Elastic Scattering and Fusion Cross Section Data for the 7Li+208Pb System at Near-Coulomb-Barrier Energies using the Folding Potential
Simultaneous analyses previously made for elastic scattering and
fusion cross section data for the Li+Pb system is extended to the
Li+Pb system at near-Coulomb-barrier energies based on the
extended optical model approach, in which the polarization potential is
decomposed into direct reaction (DR) and fusion parts. Use is made of the
double folding potential as a bare potential. It is found that the experimental
elastic scattering and fusion data are well reproduced without introducing any
normalization factor for the double folding potential and that both the DR and
fusion parts of the polarization potential determined from the
analyses satisfy separately the dispersion relation. Further, we find that the
real part of the fusion portion of the polarization potential is attractive
while that of the DR part is repulsive except at energies far below the Coulomb
barrier energy. A comparison is made of the present results with those obtained
from the Continuum Discretized Coupled Channel (CDCC) calculations and a
previous study based on the conventional optical model with a double folding
potential. We also compare the present results for the Li+Pb system
with the analysis previously made for the Li+Pb system.Comment: 7 figures, submitted to PR
Non-line-of-sight Node Localization based on Semi-Definite Programming in Wireless Sensor Networks
An unknown-position sensor can be localized if there are three or more
anchors making time-of-arrival (TOA) measurements of a signal from it. However,
the location errors can be very large due to the fact that some of the
measurements are from non-line-of-sight (NLOS) paths. In this paper, we propose
a semi-definite programming (SDP) based node localization algorithm in NLOS
environment for ultra-wideband (UWB) wireless sensor networks. The positions of
sensors can be estimated using the distance estimates from location-aware
anchors as well as other sensors. However, in the absence of LOS paths, e.g.,
in indoor networks, the NLOS range estimates can be significantly biased. As a
result, the NLOS error can remarkably decrease the location accuracy.
And it is not easy to efficiently distinguish LOS from NLOS measurements. In
this paper, an algorithm is proposed that achieves high location accuracy
without the need of identifying NLOS and LOS measurement.Comment: submitted to IEEE ICC'1
Extended Optical Model Analyses of Elastic Scattering and Fusion Cross Sections for 6Li + 208Pb System at Near-Coulomb-Barrier Energies by using Folding Potential
Based on the extended optical model approach in which the polarization
potential is decomposed into direct reaction (DR) and fusion parts,
simultaneous analyses are performed for elastic scattering and
fusion cross section data for the Li+Pb system at
near-Coulomb-barrier energies. A folding potential is used as the bare
potential. It is found that the real part of the resultant DR part of the
polarization potential is repulsive, which is consistent with the results from
the Continuum Discretized Coupled Channel (CDCC) calculations and the
normalization factors needed for the folding potentials. Further, it is found
that both DR and fusion parts of the polarization potential satisfy separately
the dispersion relation.Comment: 6 figure
Coupled-channels analyses for Li + Pb fusion reactions with multi-neutron transfer couplings
We discuss the role of two-neutron transfer processes in the fusion reaction
of the Li + Pb systems. We first analyze the Li +
Pb reaction by taking into account the coupling to the Li +
Pb channel. To this end, we assume that two neutrons are directly
transferred to a single effective channel in Pb and solve the
coupled-channels equations with the two channels. By adjusting the coupling
strength and the effective -value, we successfully reproduce the
experimental fusion cross sections for this system. We then analyze the
Li + Pb reaction in a similar manner, that is, by taking into
account three effective channels with Li + Pb, Li +
Pb, and Li + Pb partitions. In order to take into account
the halo structure of the Li nucleus, we construct the potential between
Li and Pb with a double folding procedure, while we employ a
Wood-Saxon type potential with the global Aky\"uz-Winther parameters for the
other channels. Our calculation indicates that the multiple two-neutron
transfer process plays a crucial role in the Li + Pb fusion
reaction at energies around the Coulomb barrier
Fusion reaction of a weakly-bound nucleus with a deformed target
We discuss the role of deformation of the target nucleus in the fusion
reaction of the C + Th system at energies around the Coulomb
barrier, for which C is a well-known one-neutron halo nucleus. To this
end, we construct the potential between C and Th with the double
folding procedure, assuming that the projectile nucleus is composed of the core
nucleus, C, and a valance neutron. By taking into account the halo
nature of the projectile nucleus as well as the deformation of the target
nucleus, we simultaneously reproduce the fusion cross sections for the C
+ Th and the C + Th systems. Our calculation indicates
that the net effect of the breakup and the transfer channels is small for this
system.Comment: 7 pages, 5 figure
GAP-43 expression correlates with spinal motoneuron regeneration following root avulsion
Background: The growth-associated protein GAP-43 plays a crucial role in axonal regeneration in injured neurons. Methods: We have used immunohistochemistry to investigate the expression of GAP-43 in spinal motoneurons during nerve reconstruction following root avulsion in the neonatal and adult rats. Results: Following the injury, GAP-43-immunoreactivity (IR) could be found in adult avulsed motoneurons as early as 1 day, increased from 3 to 7 days and reached a maximal level at 2 weeks post-injury. The up-regulation of GAP-43 in adult avulsed motoneurons was accompanied with the axonal regeneration indicated by numerous regenerating motor axons entering the reimplanted ventral root and nerve. In contrast, GAP-43-IR could not be found in the neonatal avulsed motoneurons at any examined post-injury time points. This failure of up-regulation of GAP-43 was coincident with no axonal regeneration in the reimplanted nerve in the neonatal rats. Conclusion: Close association of GAP-43 expression and capacity of regeneration in reimplanted spinal nerve of avulsed motoneurons suggests that GAP-43 is a potential therapeutic target for treatment of root avulsion of brachial plexus. © 2009 Yuan et al; licensee BioMed Central Ltd.published_or_final_versio
Anxiety and depression with neurogenesis defects in exchange protein directly activated by cAMP 2-deficient mice are ameliorated by a selective serotonin reuptake inhibitor, Prozac
Intracellular cAMP and serotonin are important modulators of anxiety and depression. Fluoxetine, a selective serotonin reuptake inhibitor (SSRI) also known as Prozac, is widely used against depression, potentially by activating cAMP response element-binding protein (CREB) and increasing brain-derived neurotrophic factor (BDNF) through protein kinase A (PKA). However, the role of Epac1 and Epac2 (Rap guanine nucleotide exchange factors, RAPGEF3 and RAPGEF4, respectively) as potential downstream targets of SSRI/cAMP in mood regulations is not yet clear. Here, we investigated the phenotypes of Epac1 (Epac1â / â) or Epac2 (Epac2â / â) knockout mice by comparing them with their wild-type counterparts. Surprisingly, Epac2â / â mice exhibited a wide range of mood disorders, including anxiety and depression with learning and memory deficits in contextual and cued fear-conditioning tests without affecting Epac1 expression or PKA activity. Interestingly, rs17746510, one of the three single-nucleotide polymorphisms (SNPs) in RAPGEF4 associated with cognitive decline in Chinese Alzheimerâs disease (AD) patients, was significantly correlated with apathy and mood disturbance, whereas no significant association was observed between RAPGEF3 SNPs and the risk of AD or neuropsychiatric inventory scores. To further determine the detailed role of Epac2 in SSRI/serotonin/cAMP-involved mood disorders, we treated Epac2â / â mice with a SSRI, Prozac. The alteration in open field behavior and impaired hippocampal cell proliferation in Epac2â / â mice were alleviated by Prozac. Taken together, Epac2 gene polymorphism is a putative risk factor for mood disorders in AD patients in part by affecting the hippocampal neurogenesis.published_or_final_versio
Activité anti-inflammatoire des feuilles dBorassus aethiopum Mart. (Arecaceae)
Le rĂŽnier est un palmier trĂšs utilisĂ© dans la pharmacopĂ©e traditionnelle ; Le calcinĂąt des feuilles est utilisĂ© en boisson dans lâeau pour traiter la bilharziose viscĂ©rale. La tigelle de la noix germĂ©e en dĂ©coction lutte contre lâimpuissance sexuelle, une activitĂ© anti-inflammatoire avec une inhibition de 70% de lâoedĂšme induite par la carragĂ©nine a Ă©tĂ© rĂ©vĂ©lĂ©e dans les extraits dâinflorescences mĂąles. La mĂ©thode de lâoedĂšme induit par la carragĂ©nine de Winter a Ă©tĂ© utilisĂ©e sur des rats de souche Wistar pour mettre en Ă©vidence lâactivitĂ© antiinflammatoire des feuilles de Borassus aethiopum. Lâextrait dâacĂ©tate dâĂ©thyle et sa fraction F1 Ă la dose 30 mg/kg ont une activitĂ© anti-inflammatoire voisine de celle de lâaspirine Ă 30 mg/kg; cette activitĂ© (exprimĂ©e en pourcentage dâinhibition) est respectivement de 79,21%, 73,16 et 92,53% Ă la premiĂšre heure. Ainsi Ă la cinquiĂšme heure ces pourcentages sont 69,18%, 54,59% et 58,75% respectivement pour la rĂ©fĂ©rence, lâextrait dâacĂ©tate dâĂ©thyle et la fraction F1.Mots clĂ©s: Borassus aethiopum Mart, feuilles et activitĂ© anti-inflammatoire
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