517 research outputs found

    Ultrafast photodoping and effective Fermi-Dirac distribution of the Dirac particles in Bi2Se3

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    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

    Accurate and fast 3D interactive segmentation system applied to MR brain quantification

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    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)

    Application of Paper-Based Microfluidic Analytical Devices (ÎĽPAD) in Forensic and Clinical Toxicology: A Review

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    The need for providing rapid and, possibly, on-the-spot analytical results in the case of intoxication has prompted researchers to develop rapid, sensitive, and cost-effective methods and analytical devices suitable for use in nonspecialized laboratories and at the point of need (PON). In recent years, the technology of paper-based microfluidic analytical devices (ÎĽPADs) has undergone rapid development and now provides a feasible, low-cost alternative to traditional rapid tests for detecting harmful compounds. In fact, ÎĽPADs have been developed to detect toxic molecules (arsenic, cyanide, ethanol, and nitrite), drugs, and drugs of abuse (benzodiazepines, cathinones, cocaine, fentanyl, ketamine, MDMA, morphine, synthetic cannabinoids, tetrahydrocannabinol, and xylazine), and also psychoactive substances used for drug-facilitated crimes (flunitrazepam, gamma-hydroxybutyric acid (GHB), ketamine, metamizole, midazolam, and scopolamine). The present report critically evaluates the recent developments in paper-based devices, particularly in detection methods, and how these new analytical tools have been tested in forensic and clinical toxicology, also including future perspectives on their application, such as multisensing paper-based devices, microfluidic paper-based separation, and wearable paper-based sensors

    Evidence of reduced surface electron-phonon scattering in the conduction band of Bi_{2}Se_{3} by non-equilibrium ARPES

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    The nature of the Dirac quasiparticles in topological insulators calls for a direct investigation of the electron-phonon scattering at the \emph{surface}. By comparing time-resolved ARPES measurements of the TI Bi_{2}Se_{3} with different probing depths we show that the relaxation dynamics of the electronic temperature of the conduction band is much slower at the surface than in the bulk. This observation suggests that surface phonons are less effective in cooling the electron gas in the conduction band.Comment: 5 pages, 3 figure

    Pulsed electric field processing of red grapes (cv. Rondinella): Modifications of phenolic fraction and effects on wine evolution

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    Pulsed electric field (PEF) is a non-thermal technology able to promote color and polyphenols extraction from grape skins. Most of the publications about PEF in winemaking report data concerning international varieties, poorly considering minor cultivars and the medium/long-term effects of the treatment on wine composition during storage. PEF was applied at different specific energies (2, 10, and 20 kJ kg\u20131) on grapes of the low-color red cv. Rondinella, after crushing-destemming. Pressing yield, the evolution of color, and total phenolic index (TPI) were measured during skin maceration. Moreover, the wines were characterized for basic compositional parameters, color, anthocyanin profile, phenolic composition (glories indices), metal content (Fe, Cr, and Ni), and sensory characters, two and twelve months after the processing, in comparison with untreated samples and pectolytic enzymes (PE). PEF did not affect fermentation evolution, nor did it modify wine basic composition or metal content. Treatments at 10 and 20 kJ kg\u20131 led to higher color and TPI in wines, in comparison to PE, because of increased content of anthocyanins and tannins. The sensory evaluation confirmed these findings. Modifications remained stable in wines after twelve months. Glories indices and vitisin A content highlighted greater potential stability of wine color in PEF-treated wines

    A non-conserved amino acid variant regulates differential signalling between human and mouse CD28

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    CD28 superagonistic antibodies (CD28SAb) can preferentially activate and expand immunosuppressive regulatory T cells (Treg) in mice. However, pre-clinical trials assessing CD28SAbs for the therapy of autoimmune diseases reveal severe systemic inflammatory response syndrome in humans, thereby implying the existence of distinct signalling abilities between human and mouse CD28. Here, we show that a single amino acid variant within the C-terminal proline-rich motif of human and mouse CD28 (P212 in human vs. A210 in mouse) regulates CD28-induced NF-ÎşB activation and pro-inflammatory cytokine gene expression. Moreover, this Y209APP212 sequence in humans is crucial for the association of CD28 with the Nck adaptor protein for actin cytoskeleton reorganisation events necessary for CD28 autonomous signalling. This study thus unveils different outcomes between human and mouse CD28 signalling to underscore the importance of species difference when transferring results from preclinical models to the bedside

    The social return on investment (SROI) of four microfinance projects

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    The paper develops an SROI (Social Return on Investment) analysis of four microfinance institutions (MFIs) located in Spain, Italy and Bosnia-Herzegovina. This work is part of the MeMI Project (\u201cMeasuring Microfinance Impact in the EU. Policy recommendations for Financial and Social Inclusion\u201d) funded by the EIBURS. It is an attempt to translate microcredit outcome indicators into a social return, quantified in monetary terms. After preliminary focus group analyses and staff interviews, data on outcomes of selected microcredit lines have been collected through a questionnaire administered to the borrowers. By comparing the monetary value of these outcomes (translated into an estimated impact) with the amount of related investment, we find that SROI is greater than 2 for all the credit lines analysed, meaning that every euro invested in microcredit generates at least 2 euros of social return. We also find SROI ranging between 2.33 and 6.97, mirroring the differences between MFIs in terms of target, operating model and country-level financial environment. Although the analysis is conducted on a limited number of cases and SROI calculation can be sharpened, it shows how different factors and outcomes drive the social return generated by microcredit

    Stem-like and highly invasive prostate cancer cells expressing CD44v8-10 marker originate from CD44-negative cells

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    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
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