491 research outputs found
Evidence of reduced surface electron-phonon scattering in the conduction band of Bi_{2}Se_{3} by non-equilibrium ARPES
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
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
Review of the Scientific Literature on Biology, Ecology, and Aspects Related to the Fishing Sector of the Striped Venus (Chamelea gallina) in Northern Adriatic Sea
Striped venus (Chamelea gallina) is one of the most important fish resources on the west coast of the Adriatic Sea. Recently, there has been a widespread die-off of C. gallina populations in Friuli-Venezia Giulia (northern Adriatic Sea, Italy), probably due to unfavorable climatic events. Overall, wild populations have become increasingly rare due to many factors affecting the ecological balance of the species. In this study, the available literature was reviewed to determine the current state of knowledge on the biology, ecology, fisheries, and status of C. gallina populations with reference to populations in Friuli-Venezia Giulia. However, few data are available in terms of peer-reviewed articles; much of it can be found in the gray literature (e.g., project reports, ministerial reports, institutional websites, etc.). However, a critical review of the sources reveals that the species is as endangered as the habitats it inhabits. As a result, conservation and restoration efforts have been undertaken to date as part of some larger project to protect the species. Therefore, considering the ecological and economic importance of this species, the results of the new studies will be useful for the scientific community and will be a key element in the conservation of this species
Application of Paper-Based Microfluidic Analytical Devices (ÎĽPAD) in Forensic and Clinical Toxicology: A Review
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
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
Probing Intermolecular H-Bonding Interactions in Cyanuric Acid Networks: Quenching of the N K-Edge Sigma Resonances
The electronic characterization of the cyanuric acid both in gas phase and when embedded within an H-bonded scheme forming a monolayer on the Au(111) surface has been performed by means of X-ray Photoelectron Spectroscopy (XPS) and Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy. The experimental spectra at the N, O, and C K-edges have been assigned with the support of DFT calculations, and the combination between theory and experiment has allowed to us investigate the effect of the H-bonding intermolecular interaction on the spectra. In particular, the H-bond formation in the monolayer leads to a quenching of the N 1s NEXAFS resonances associated with transitions to the sigma empty orbitals localized on the N-H portion of the imide group. On the other hand, the pi* empty states remain substantially unperturbed. From a computational point of view, it has been shown that the DFT-TP scheme is not able to describe the N 1s NEXAFS spectra of these systems, and the configuration mixing has to be included, through the TDDFT approach in conjunction with the range-separated XC CAM-B3LYP functional, to obtain a correct reproduction of the N 1s core spectra
Estrogen-receptor-positive breast cancer in postmenopausal women: The role of body composition and physical exercise
Breast cancer (BC) is the most commonly diagnosed cancer among women worldwide and the most common cause of cancer-related death. To date, it is still a challenge to estimate the magnitude of the clinical impact of physical activity (PA) on those parameters producing significative changes in future BC risk and disease progression. However, studies conducted in recent years highlight the role of PA not only as a protective factor for the development of ER+ breast cancer but, more generally, as a useful tool in the management of BC treatment as an adjuvant to traditional therapies. In this review, we focused our attention on data obtained from human studies analyzing, at each level of disease prevention (i.e., primary, secondary, tertiary and quaternary), the positive impact of PA/exercise in ER+ BC, a subtype representing approximately 70% of all BC diagnoses. Moreover, given the importance of estrogen receptors and body composition (i.e., adipose tissue) in this subtype of BC, an overview of their role will also be made throughout this review
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