767 research outputs found
Ultrafast photodoping and effective Fermi-Dirac distribution of the Dirac particles in Bi2Se3
We exploit time- and angle- resolved photoemission spectroscopy to determine
the evolution of the out-of-equilibrium electronic structure of the topological
insulator Bi2Se. The response of the Fermi-Dirac distribution to ultrashort IR
laser pulses has been studied by modelling the dynamics of the hot electrons
after optical excitation. We disentangle a large increase of the effective
temperature T* from a shift of the chemical potential mu*, which is consequence
of the ultrafast photodoping of the conduction band. The relaxation dynamics of
T* and mu* are k-independent and these two quantities uniquely define the
evolution of the excited charge population. We observe that the energy
dependence of the non-equilibrium charge population is solely determined by the
analytical form of the effective Fermi-Dirac distribution.Comment: 5 Pages, 3 Figure
COMPARATIVE ANALYSIS OF TECHNICAL, ECONOMICAL AND ENVIRONMENTAL FEASIBILITY OF COGENERATION PLANT USING WOOD BIOMASS
After having identified, in a previous work [6], the possible sites for the location of a new cogeneration plant using wood biomass in the Mountain Community of Carnia, Friuli Venezia Giulia Region (Italy), the technical and economic feasibility and environmental sustainability of such a system has been carried out in order to evaluate the feasibility of the proposed solution
Accurate and fast 3D interactive segmentation system applied to MR brain quantification
This work presents an efficient interactive segmentation system for volumetric data-sets based on advanced 3D morphological analyses and an interaction paradigm that allows a good match with user intentions. This system has been designed to produce accurate results under the complete control of the user, to minimize the interaction time and to address a generality of 3D segmentation tasks. The system has been tested and compared with other softwares on normal MR brain structure quantification and on a challenging clinical setting pointed to the detection of the presence of subtle brain atrophy associated to primitive immunodeficiency (PID)
COMPARATIVE ANALYSIS OF TECHNICAL, ECONOMICAL AND ENVIRONMENTAL FEASIBILITY OF COGENERATION PLANT USING WOOD BIOMASS
After having identified, in a previous work [6], the possible sites for the location of a new cogeneration plant using wood biomass in the Mountain Community of Carnia, Friuli Venezia Giulia Region (Italy), the technical and economic feasibility and environmental sustainability of such a system has been carried out in order to evaluate the feasibility of the proposed solution
Chemical composition of microplastic in sediments and protected detritivores from different marine habitats (Salina Island)
This study estimates chemical composition of microplastic in sediments and benthic detritivores (sea cucumbers) collected from different marine rocky bottom habitat types (bank, landslide, cliff) of Salina Island (Aeolian Archipelago, Italy). Also, species richness and bottom coverings by benthic species were recorded at each sampling station. Correlations among chemical composition of microplastic in sediments and in detritivores were explored linking recorded variability to the factor \u201chabitat type\u201d. Results evidence that the habitat types considered in this study are characterized by wide species richness and by high percentages of bottom coverage by protected species by international conventions. In spite of the high ecological value of habitats considered in this study, microplastics were recorded both in sediments (PVC, PET, PE, PS, PA, PP) and in stomach contents of sea cucumbers (PET, PA) collected in all sampling sites, confirming the exposure of benthic species to microplastic pollution
Stem-like and highly invasive prostate cancer cells expressing CD44v8-10 marker originate from CD44-negative cells
In human prostate cancer (PCa), the neuroendocrine cells, expressing the prostate cancer stem cell (CSC) marker CD44, may be resistant to androgen ablation and promote tumor recurrence. During the study of heterogeneity of the highly aggressive neuroendocrine PCa cell lines PC3 and DU-145, we isolated and expanded in vitro a minor subpopulation of very small cells lacking CD44 (CD44neg). Unexpectedly, these sorted CD44neg cells rapidly and spontaneously converted to a stable CD44high phenotype specifically expressing the CD44v8-10 isoform which the sorted CD44high subpopulation failed to express. Surprisingly and potentially interesting, in these cells expression of CD44v8-10 was found to be induced in stem cell medium. CD44 variant isoforms are known to be more expressed in CSC and metastatic cells than CD44 standard isoform. In agreement, functional analysis of the two sorted and cultured subpopulations has shown that the CD44v8-10pos PC3 cells, resulting from the conversion of the CD44neg subpopulation, were more invasive in vitro and had a higher clonogenic potential than the sorted CD44high cells, in that they produced mainly holoclones, known to be enriched in stem-like cells. Of interest, the CD44v8-10 is more expressed in human PCa biopsies than in normal gland. The discovery of CD44v8-10pos cells with stem-like and invasive features, derived from a minoritarian CD44neg cell population in PCa, alerts on the high plasticity of stem-like markers and urges for prudency on the approaches to targeting the putative CSC
Circular dichroism and bilayer splitting in the normal state of underdoped (Pb,Bi)Sr(CaY)CuO and overdoped (Pb,Bi)SrCaCuO
We report an ARPES investigation of the circular dichroism in the first
Brillouin zone (BZ) of under- and overdoped Pb-Bi2212 samples. We show that the
dichroism has opposite signs for bonding and antibonding components of the
bilayer-split CuO-band and is antisymmetric with respect to reflections in both
mirror planes parallel to the c-axis. Using this property of the energy and
momentum intensity distributions we prove the existence of the bilayer
splitting in the normal state of the underdoped compound and compare its value
with the splitting in overdoped sample. In agreement with previous studies the
magnitude of the interlayer coupling does not depend significantly on doping.
We also discuss possible origins of the observed dichroism.Comment: 4 RevTex pages, 4 EPS figure
Correlated Electrons Step-by-Step: Itinerant-to-Localized Transition of Fe Impurities in Free-Electron Metal Hosts
High-resolution photoemission spectroscopy and realistic ab-initio
calculations have been employed to analyze the onset and progression of d-sp
hybridization in Fe impurities deposited on alkali metal films. The interplay
between delocalization, mediated by the free-electron environment, and Coulomb
interaction among d-electrons gives rise to complex electronic configurations.
The multiplet structure of a single Fe atom evolves and gradually dissolves
into a quasiparticle peak near the Fermi level with increasing the host
electron density. The effective multi-orbital impurity problem within the exact
diagonalization scheme describes the whole range of hybridizations.Comment: 10 pages, 4 figure
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