2,363 research outputs found

    A template-matching algorithm for laminar identification of cortical recording sites from evoked response potentials

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    In recent years, the advent of the so-called silicon probes has made it possible to homogeneously sample spikes and local field potentials (LFPs) from a regular grid of cortical recording sites. In principle, this allows inferring the laminar location of the sites based on the spatiotemporal pattern of LFPs recorded along the probe, as in the well-known current source-density (CSD) analysis. This approach, however, has several limitations, since it relies on visual identification of landmark features (i.e., current sinks and sources) by human operators, features that can be absent from the CSD pattern if the probe does not span the whole cortical thickness, thus making manual labeling harder. Furthermore, as with any manual annotation procedure, the typical CSD-based workflow for laminar identification of recording sites is affected by subjective judgment undermining the consistency and reproducibility of results. To overcome these limitations, we developed an alternative approach, based on finding the optimal match between the LFPs recorded along a probe in a given experiment and a template LFP profile that was computed using 18 recording sessions, in which the depth of the recording sites had been recovered through histology. We show that this method can achieve an accuracy of 79 \u3bcm in recovering the cortical depth of recording sites and a 76% accuracy in inferring their laminar location. As such, our approach provides an alternative to CSD that, being fully automated, is less prone to the idiosyncrasies of subjective judgment and works reliably also for recordings spanning a limited cortical stretch. NEW & NOTEWORTHY Knowing the depth and laminar location of the microelectrodes used to record neuronal activity from the cerebral cortex is crucial to properly interpret the recorded patterns of neuronal responses. Here, we present an innovative approach that allows inferring such properties with high accuracy and in an automated way (i.e., without the need of visual inspection and manual annotation) from the evoked response potentials elicited by sensory (e.g., visual) stimuli

    IMPs: an RNA-binding protein family that provides a link between stem cell maintenance in normal development and cancer.

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    IMPs, also known as insulin-like growth factor 2 (IGF2) messenger RNA (mRNA)-binding proteins (IGF2BPs), are highly conserved oncofetal RNA-binding proteins (RBPs) that regulate RNA processing at several levels, including localization, translation, and stability. Three mammalian IMP paralogs (IMP1-3) have been identified that are expressed in most organs during embryogenesis, where they are believed to play an important role in cell migration, metabolism, and stem cell renewal. Whereas some IMP2 expression is retained in several adult mouse organs, IMP1 and IMP3 are either absent or expressed at very low levels in most tissues after birth. However, all three paralogs can be re-expressed upon malignant transformation and are found in a broad range of cancer types where their expression often correlates with poor prognosis. IMPs appear to resume their physiological functions in malignant cells, which not only contribute to tumor progression but participate in the establishment and maintenance of tumor cell hierarchies. This review summarizes our current understanding of the functions of IMPs during normal development and focuses on a series of recent observations that have provided new insight into how their physiological functions enable IMPs to play a potentially key role in cancer stem cell maintenance and tumor growth

    5-Hydroxymethylcytosine Loss in Conjunctival Melanoma.

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    Conjunctival and cutaneous melanoma partially share similar clinical and molecular backgrounds. As 5-hydroxymethylcytosine (5-hmC) loss has been demonstrated in cutaneous melanoma, we decided to assess if similar changes were occurring in conjunctival melanoma. 5-methylcytosine (5-mC), 5-hmC and TET2 were respectively identified by immunohistochemistry and RNA ISH in 40 conjunctival nevi and 37 conjunctival melanomas. Clinicopathological correlations were established. 5-mC, TET2 and 5-hmC were respectively identified in 67.5%, 95% and 100% of conjunctival nevi and in 81.1%, 35.1% and 54% of conjunctival melanomas. A significant 5-hmC and TET2 loss was identified in conjunctival melanoma comparing to nevus, as well as a significant correlation between TET2 and 5-hmC expression. In the melanomas, 5-hmC expression was only significantly associated with local lymphatic invasion, but not with other clinicopathological parameters. There was a correlation between TET2 expression and the localization of the tumors. 5-mC expression was not associated with any clinicopathological parameters. We identified a significant 5-hmC loss in conjunctival melanoma similar to cutaneous melanoma. This loss may possibly be attributed to TET2 loss or IDH1 mutations. 5-hmC loss in conjunctival melanoma may help in the differential diagnosis between atypical conjunctival nevus and conjunctival melanoma

    The polarization mode of the auroral radio emission from the early-type star HD142301

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    We report the detection of the auroral radio emission from the early-type magnetic star HD142301. New VLA observations of HD142301 detected highly polarized amplified emission occurring at fixed stellar orientations. The coherent emission mechanism responsible for the stellar auroral radio emission amplifies the radiation within a narrow beam, making the star where this phenomenon occurs similar to a radio lighthouse. The elementary emission process responsible for the auroral radiation mainly amplifies one of the two magneto-ionic modes of the electromagnetic wave. This explains why the auroral pulses are highly circularly polarized. The auroral radio emission of HD142301 is characterized by a reversal of the sense of polarization as the star rotates. The effective magnetic field curve of HD142301 is also available making it possible to correlate the transition from the left to the right-hand circular polarization sense (and vice-versa) of the auroral pulses with the known orientation of the stellar magnetic field. The results presented in this letter have implications for the estimation of the dominant magneto-ionic mode amplified within the HD142301 magnetosphere.Comment: 5 pages, 4 figures; accepted to MNRAS Letter

    Phase I study of high-dose epirubicin and vinorelbine in previously untreated non-small-cell lung cancer stage IIIB-IV.

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    The aim of the study was to determine the maximum tolerated dose (MTD) for the combination of high-dose epirubicin and vinorelbine in chemotherapy-naive patients with inoperable non-small-cell lung cancer (NSCLC). Twenty-one patients with stage IIIB and IV NSCLC were treated in a single-centre study with escalating doses of epirubicin and vinorelbine given on an outpatient basis. The first dose level comprised epirubicin 100 mg m-2 on day 1 and vinorelbine 20 mg m-2 (days 1 and 8) given intravenously every 3 weeks. Escalating doses for epirubicin and vinorelbine were respectively 120 (day 1) and 20 (days 1 and 8), 120 (day 1) and 25 (days 1 and 8) and 135 (day 1) and 25 (days 1 and 8) mg m-2. Inclusion criteria were age < or = 75 years, ECOG performance score < or = 2 and normal renal, hepatic and bone marrow functions. Dose-limiting toxicities were thrombocytopenia grade II and neutropenia grade III on day 8, febrile neutropenia, and neutropenia lasting > 7 days. No dose-limiting toxicity (DLT) was observed at the first dose level; at the 135/25 mg m-2 dose level three out of six patients had a DLT which was considered as unacceptable. The only non-haematological toxicity reaching grade III was nausea/vomiting. One patient showed cardiac toxicity. No neurotoxicity and no treatment-related deaths were seen. The maximum tolerated dose of epirubicin and vinorelbine is 135 mg m-2 (day 1) and 25 mg m-2 (days 1 and 8) respectively, causing mainly haematological toxicity. The recommended dose of epirubicin and vinorelbine for phase II studies is found to be 120 mg m-2 and 20 mg m-2 respectively

    SCORPIO-II: Spectral indices of weak Galactic radio sources

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    In the next few years the classification of radio sources observed by the large surveys will be a challenging problem, and spectral index is a powerful tool for addressing it. Here we present an algorithm to estimate the spectral index of sources from multiwavelength radio images. We have applied our algorithm to SCORPIO (Umana et al. 2015), a Galactic Plane survey centred around 2.1 GHz carried out with ATCA, and found we can measure reliable spectral indices only for sources stronger than 40 times the rms noise. Above a threshold of 1 mJy, the source density in SCORPIO is 20 percent greater than in a typical extra-galactic field, like ATLAS (Norris et al. 2006), because of the presence of Galactic sources. Among this excess population, 16 sources per square degree have a spectral index of about zero, suggesting optically thin thermal emission such as Hii regions and planetary nebulae, while 12 per square degree present a rising spectrum, suggesting optically thick thermal emission such as stars and UCHii regions.Comment: 12 pages, 11 figures, accepted by MNRA

    Clustering analysis for muon tomography data elaboration in the Muon Portal project

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    Clustering analysis is one of multivariate data analysis techniques which allows to gather statistical data units into groups, in order to minimize the logical distance within each group and to maximize the one between different groups. In these proceedings, the authors present a novel approach to the muontomography data analysis based on clustering algorithms. As a case study we present the Muon Portal project that aims to build and operate a dedicated particle detector for the inspection of harbor containers to hinder the smuggling of nuclear materials. Clustering techniques, working directly on scattering points, help to detect the presence of suspicious items inside the container, acting, as it will be shown, as a filter for a preliminary analysis of the data

    Piezoelectric Rainfall Energy Harvester Performance by Advanced Arduino based Measuring System

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    This paper presents the performances of rainfall energy harvesting through the use of a piezoelectric transducer and an Arduino-based measuring system. Different studies agree on the possibility of generating electricity from rainfall, but to date, a study on measuring the quantity of energy produced during rainfall is still missing. The present study begins with results obtained from laboratory researchers using piezoelectric transducers and oscilloscopes, finalized to measure the energy produced from a single raindrop, and concludes with an ad hoc Arduino-based measuring system, aimed to measure the actual amount of electrical energy produced by a piezoelectric transducer that is exposed to rainfall of variable durations
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