445 research outputs found

    Discontinuous Transition from a Real Bound State to Virtual Bound State in a Mixed-Valence State of SmS

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    Golden SmS is a paramagnetic, mixed-valence system with a pseudogap. With increasing pressure across a critical pressure Pc, the system undergoes a discontinuous transition into a metallic, anti-ferromagnetically ordered state. By using a combination of thermodynamic, transport, and magnetic measurements, we show that the pseudogap results from the formation of a local bound state with spin singlet. We further argue that the transition Pc is regarded as a transition from an insulating electron-hole gas to a Kondo metal, i.e., from a spatially bound state to a Kondo virtually bound state between 4f and conduction electrons.Comment: 5 pages, 5 figure

    Dp71 expression in human glioblastoma

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    Background: Dp71 is the most abundant dystrophin (DMD) gene product in the nervous system. Mutation in the Dp71 coding region is associated with cognitive disturbances in Duchenne muscular dystrophy (DMD) patients, but the function of dystrophin Dp71 in tumor progression remains to be established. This study investigated Dp71 expression in glioblastoma, the most common and aggressive primary tumor of the central nervous system (CNS). Methods: Dp71 expression was analyzed by immunofluorescence, immunohistochemistry, RT-PCR, and immunoblotting in glioblastoma cell lines and cells isolated from human glioblastoma multiforme (GBM) bioptic specimens. Results: Dp71 isoform was expressed in normal human astrocytes (NHA) cell lines and decreased in glioblastoma cell lines and cells isolated from human glioblastoma multiforme bioptic specimens. Moreover, Dp71 was localized in the nucleus in normal cells, while it was localized into the cytoplasm of glioblastoma cells organized in clusters. We have shown, by double labeling, that Dp71 colocalizes with lamin B in normal astrocytes cells, confirming the roles of Dp71 and lamin B in maintaining nuclear architecture. Finally, we demonstrated that decreased Dp71 protein in cells isolated from human bioptic specimens was inversely correlated with the Ki-67 tumor proliferative index. Conclusion: A decreased Dp71 expression is associated with cancer proliferation and poor prognosis in glioblastoma

    Oral beclometasone dipropionate in the treatment of active ulcerative colitis: a double-blind placebo-controlled study.

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    AIM: To evaluate efficacy and safety of oral beclometasone dipropionate (BDP) when added to 5-ASA in the treatment of patients with active ulcerative colitis. METHODS: In a 4-week, placebo-controlled, double-blind study, patients with extensive or left-sided mild to moderate active ulcerative colitis were randomized to receive oral 5-ASA (3.2 g/day) plus BDP (5 mg/day) or placebo. Clinical, endoscopic and histologic features, and haematochemical parameters were recorded at baseline and at the end of the study

    Postmortem examination of patient H.M.’s brain based on histological sectioning and digital 3D reconstruction

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    Modern scientific knowledge of how memory functions are organized in the human brain originated from the case of Henry G. Molaison (H.M.), an epileptic patient whose amnesia ensued unexpectedly following a bilateral surgical ablation of medial temporal lobe structures, including the hippocampus. The neuroanatomical extent of the 1953 operation could not be assessed definitively during H.M.’s life. Here we describe the results of a procedure designed to reconstruct a microscopic anatomical model of the whole brain and conduct detailed 3D measurements in the medial temporal lobe region. This approach, combined with cellular-level imaging of stained histological slices, demonstrates a significant amount of residual hippocampal tissue with distinctive cytoarchitecture. Our study also reveals diffuse pathology in the deep white matter and a small, circumscribed lesion in the left orbitofrontal cortex. The findings constitute new evidence that may help elucidate the consequences of H.M.’s operation in the context of the brain’s overall pathology

    Prostate cancer biomarkers: a practical review based on different clinical scenarios

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    Traditionally, diagnosis and staging of prostate cancer (PCa) have been based on prostate-specific antigen (PSA) level, digital rectal examination (DRE), and transrectal ultrasound (TRUS) guided prostate biopsy. Biomarkers have been introduced into clinical practice to reduce the overdiagnosis and overtreatment of low-grade PCa and increase the success of personalized therapies for high-grade and high-stage PCa. The purpose of this review was to describe available PCa biomarkers and examine their use in clinical practice. A nonsystematic literature review was performed using PubMed and Scopus to retrieve papers related to PCa biomarkers. In addition, we manually searched websites of major urological associations for PCa guidelines to evaluate available evidence and recommendations on the role of biomarkers and their potential contribution to PCa decision-making. In addition to PSA and its derivates, thirteen blood, urine, and tissue biomarkers are mentioned in various PCa guidelines. Retrospective studies have shown their utility in three main clinical scenarios: (1) deciding whether to perform a biopsy, (2) distinguishing patients who require active treatment from those who can benefit from active surveillance, and (3) defining a subset of high-risk PCa patients who can benefit from additional therapies after RP. Several validated PCa biomarkers have become commercially available in recent years. Guidelines now recommend offering these tests in situations in which the assay result, when considered in combination with routine clinical factors, is likely to affect management. However, the lack of direct comparisons and the unproven benefits, in terms of long-term survival and cost-effectiveness, prevent these biomarkers from being integrated into routine clinical use

    Valence band electronic structure of V2O3: identification of V and O bands

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    We present a comprehensive study of the photon energy dependence of the valence band photoemission yield in the prototype Mott-Hubbard oxide V2O3. The analysis of our experimental results, covering an extended photon energy range (20-6000 eV) and combined with GW calculations, allow us to identify the nature of the orbitals contributing to the total spectral weight at different binding energies, and in particular to locate the V 4s at about 8 eV binding energy. From this comparative analysis we can conclude that the intensity of the quasiparticle photoemission peak, observed close to the Fermi level in the paramagnetic metallic phase upon increasing photon energy, does not have a significant correlation with the intensity variation of the O 2p and V 3d yield, thus confirming that bulk sensitivity is an essential requirement for the detection of this coherent low energy excitation

    Depth dependence of itinerant character in Mn-substituted Sr3Ru2O7

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    We present a core-level photoemission study of Sr3(Ru 1-xMnx)2O7, in which we monitor the evolution of the Ru-3d fine structure versus Mn substitution and probing depth. In both Ru 3d3/2 and 3d5/2 core levels we observe a clear suppression of the metallic features, i.e. the screened peaks, implying a sharp transition from itinerant to localized character already at low Mn concentrations. The comparison between soft and hard x-ray photoemission, which provides tunable depth sensitivity, reveals that the degree of localized/metallic character for Ru is different at the surface than in the bulk.Comment: 10 pages, 4 figures, 1 tabl

    Effect of resveratrol on mitochondrial function: Implications in parkin-associated familiar Parkinson's disease

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    Mitochondrial dysfunction and oxidative stress occur in Parkinson's disease (PD), but the molecular mechanisms controlling these events are not completely understood. Peroxisome proliferator-activated receptor-gamma coactivator-1α (PGC-1α) is a transcriptional coactivator known as master regulator of mitochondrial functions and oxidative metabolism. Recent studies, including one from our group, have highlighted altered PGC-1α activity and transcriptional deregulation of its target genes in PD pathogenesis suggesting it as a new potential therapeutic target. Resveratrol, a natural polyphenolic compound proved to improve mitochondrial activity through the activation of several metabolic sensors resulting in PGC-1α activation. Here we have tested in vitro the effect of resveratrol treatment on primary fibroblast cultures from two patients with early-onset PD linked to different Park2 mutations. We show that resveratrol regulates energy homeostasis through activation of AMP-activated protein kinase (AMPK) and sirtuin 1 (SIRT1) and raise of mRNA expression of a number of PGC-1α's target genes resulting in enhanced mitochondrial oxidative function, likely related to a decrease of oxidative stress and to an increase of mitochondrial biogenesis. The functional impact of resveratrol treatment encompassed an increase of complex I and citrate synthase activities, basal oxygen consumption, and mitochondrial ATP production and a decrease in lactate content, thus supporting a switch from glycolytic to oxidative metabolism. Moreover, resveratrol treatment caused an enhanced macro-autophagic flux through activation of an LC3-independent pathway. Our results, obtained in early-onset PD fibroblasts, suggest that resveratrol may have potential clinical application in selected cases of PD-affected patients

    Ultralow-light-level color image reconstruction using high-efficiency plasmonic metasurface mosaic filters

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    As single-photon imaging becomes progressively more commonplace in sensing applications such as low-light-level imaging, three-dimensional profiling, and fluorescence imaging, there exist a number of fields where multispectral information can also be exploited, e.g., in environmental monitoring and target identification. We have fabricated a high-transmittance mosaic filter array, where each optical filter was composed of a plasmonic metasurface fabricated in a single lithographic step. This plasmonic metasurface design utilized an array of elliptical and circular nanoholes, which produced enhanced optical coupling between multiple plasmonic interactions. The resulting metasurfaces produced narrow bandpass filters for blue, green, and red light with peak transmission efficiencies of 79%, 75%, and 68%, respectively. After the three metasurface filter designs were arranged in a 64×64 format random mosaic pattern, this mosaic filter was directly integrated onto a CMOS single-photon avalanche diode detector array. Color images were then reconstructed at light levels as low as approximately 5 photons per pixel, on average, via the simultaneous acquisition of low-photon multispectral data using both three-color active laser illumination and a broadband white-light illumination source
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