1,335 research outputs found

    The Next Generation Virgo Cluster Survey (NGVS). XVIII. Measurement and Calibration of Surface Brightness Fluctuation Distances for Bright Galaxies in Virgo (and Beyond)

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    We describe a program to measure surface brightness fluctuation (SBF) distances to galaxies observed in the Next Generation Virgo Cluster Survey (NGVS), a photometric imaging survey covering 104 deg2104~deg^2 of the Virgo cluster in the u,g,i,z{u}^*,g,i,z bandpasses with the Canada-France Hawaii Telescope. We describe the selection of the sample galaxies, the procedures for measuring the apparent ii-band SBF magnitude iˉ\bar{i}, and the calibration of the absolute Mˉi\bar{M}_i as a function of observed stellar population properties. The multi-band NGVS data set provides multiple options for calibrating the SBF distances, and we explore various calibrations involving individual color indices as well as combinations of two different colors. Within the color range of the present sample, the two-color calibrations do not significantly improve the scatter with respect to wide-baseline, single-color calibrations involving uu^{*}. We adopt the uz{u}^*{-}z calibration as reference for the present galaxy sample, with an observed scatter of 0.11 mag. For a few cases that lack good u{u}^* photometry, we use an alternative relation based on a combination of gig{-}i and gzg{-}z colors, with only a slightly larger observed scatter of 0.12 mag. The agreement of our measurements with the best existing distance estimates provides confidence that our measurements are accurate. We present a preliminary catalog of distances for 89 galaxies brighter than BT13.0B_T\approx13.0 mag within the survey footprint, including members of the background M and W Clouds at roughly twice the distance of the main body of the Virgo cluster. The extension of the present work to fainter and bluer galaxies is in progress.Comment: ApJ accepte

    Chronic myelogenous leukaemia exosomes modulate bone marrow microenvironment through activation of epidermal growth factor receptor

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    Chronic myelogenous leukaemia (CML) is a clonal myeloproliferative disorder. Recent evidence indicates that altered crosstalk between CML and mesenchymal stromal cells may affect leukaemia survival; moreover, vesicles released by both tumour and non-tumour cells into the microenvironment provide a suitable niche for cancer cell growth and survival. We previously demonstrated that leukaemic and stromal cells establish an exosome-mediated bidirectional crosstalk leading to the production of IL8 in stromal cells, thus sustaining the survival of CML cells. Human cell lines used are LAMA84 (CML cells), HS5 (stromal cells) and bone marrow primary stromal cells; gene expression and protein analysis were performed by real-time PCR and Western blot. IL8 and MMP9 secretions were evaluated by ELISA. Exosomes were isolated from CML cells and blood samples of CML patients. Here, we show that LAMA84 and CML patients\u2019 exosomes contain amphiregulin (AREG), thus activating epidermal growth factor receptor (EGFR) signalling in stromal cells. EGFR signalling increases the expression of SNAIL and its targets, MMP9 and IL8. We also demonstrated that pre-treatment of HS5 with LAMA84 exosomes increases the expression of annexin A2 that promotes the adhesion of leukaemic cells to the stromal monolayer, finally supporting the growth and invasiveness of leukaemic cells. Leukaemic and stromal cells establish a bidirectional crosstalk: exosomes promote proliferation and survival of leukaemic cells, both in vitro and in vivo, by inducing IL8 secretion from stromal cells. We propose that this mechanism is activated by a ligand\u2013receptor interaction between AREG, found in CML exosomes, and EGFR in bone marrow stromal cells

    A sensor aided H.264 encoder tested on aerial imagery for SFM

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    Email Print Request Permissions Standard video coding systems currently employed in UAV (Unmanned Aerial Vehicle) and aerial drone applications do not rely on some peculiarities in terms of scene 3D model and correlation among successive frames. In particular, the observed scene is static, i.e. the camera movement is dominant, and it can often be well approximated with a plane. Moreover, camera position and orientation can be obtained from the navigation system. Therefore, correspondent points on two video frames are linked by a simple homography. This paper presents novel results obtained by a low-complexity sensor aided H.264 encoder, recently developed at CIRA and yet tested on simulated data. The proposed encoder employs a new motion estimation scheme which make use of the global motion information provided by the onboard navigation system. The homography is used in order to initialize the block matching algorithm allowing a more robust motion estimation and a smaller search window, and hence reducing the complexity. The tests are made coding real aerial imagery, captured to be used for 3D scene reconstruction. The images are acquired by an high resolution camera mounted on a small drone, flying at low altitude

    Robotic Surgery and Deep Infiltrating Endometriosis Treatment: The State of Art

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    Objective: Surgical treatment of endometriosis, when indicated, has demonstrated to be effective in reducing painful symptoms and improve quality of life of patients affected with endometriosis. The minimally invasive approach via laparoscopy is the preferred method when compared with laparotomy but in the last two decades another minimally invasive approach has become available, the robotically assisted laparoscopic surgery. Robotic technology is widely used in different surgical branches, such as general surgery and urology. Moreover, the use of robotic surgery is already accepted for different gynecological procedures either for benign and for oncological diseases. The advantages of robotic surgery such as improve dexterity of movements, avoided tremor, increased magnification of 3-dimensional vision seem strategic in the context of a complex surgery as is deep endometriosis eradication. However, to date there is no unanimous consensus on whether robotically assisted procedures are a valid and safe alternative to laparoscopy in the treatment of endometriosis. Mechanism: In this narrative review we analyze the available literature assessesing the robotic treatment of all types of endometriosis and specifically deep infiltrating endometriosis, compared to the outcomes of conventional laparoscopy. Findings in Brief: Indeed, the evidence of safety and effectiveness of robotically assisted laparoscopy in endometriosis treatment is strong and almost unanimous. There is no clear superiority of one approach to the other but robotic-related advantages and future prospective are promising to be able to improve operative outcomes, reduce surgeon’s fatigue and provide a technology easy to implement with a fast learning curve. Conclusions: Robotic technology applied to laparoscopy in the treatment of endometriosis could be seen as an effective and safe alternative to the conventional laparoscopic treatment

    UV irradiated graphene-based nanocomposites: Change in the mechanical properties by local harmoniX atomic force microscopy detection

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    Epoxy based coatings are susceptible to ultra violet (UV) damage and their durability can be significantly reduced in outdoor environments. This paper highlights a relevant property of graphene-based nanoparticles: Graphene Nanoplatelets (GNPs) incorporated in an epoxy-based free-standing film determine a strong decrease of the mechanical damages caused by UV irradiation. The effects of UV light on the morphology and mechanical properties of the solidified nanocharged epoxy films are investigated by Atomic Force Microscopy (AFM), in the acquisition mode "HarmoniX." Nanometric-resolved maps of the mechanical properties of the multi-phase material evidence that the incorporation of low percentages, between 0.1% and 1.0% by weight, of graphene nanoplatelets (GNPs) in the polymeric film causes a relevant enhancement in the mechanical stability of the irradiated films. The beneficial effect progressively increases with increasing GNP percentage. The paper also highlights the potentiality of AFM microscopy, in the acquisition mode "HarmoniX" for studying multiphase polymeric systems

    Morphological, rheological and electrical properties of composites filled with carbon nanotubes functionalized with 1-pyrenebutyric acid

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    Non-covalent functionalization of Multi Wall Carbon Nanotubes (MWCNTs) could provide a solution for preserving their electronic structure facilitating the nanocomposite process preparation. Functionalization of MWCNTs by π-stacking interaction between nanofiller and a pyrene derivative has been explored. The rheological properties of filled epoxy resins highlight very interesting benefits from this kind of functionalization. Besides its peculiar capability for preventing agglomeration in the nanofiller dispersion step, it also efficiently contributes to a decrease in the viscosity of the nanocomposites; hence contrasting one of the most relevant drawback related to the manufacturing processes of the nanocomposites at MWCNTs loading rates beyond the Electrical Percolation Threshold (EPT). Because no damage of MWCNTs occurs, sp2 hybridization of carbon atoms is preserved together with the π-electron delocalization typical of polynuclear aromatic rings. Consequently, no deterioration in the electrical properties are detected; the measured EPT values are typical of nanocomposites containing embedded unfunctionalized MWCNTs (lower than 0.28 wt%), whereas for the electrical conductivity beyond the EPT, an enhancement is observed

    BCR-ABL1 doubling-times and halving-times may predict CML response to tyrosine kinase inhibitors

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    In Chronic Myeloid Leukemia (CML), successful treatment requires accurate molecular monitoring to evaluate disease response and provide timely interventions for patients failing to achieve the desired outcomes. We wanted to determine whether measuring BCR-ABL1 mRNA doubling-times (DTs) could distinguish inconsequential rises in the oncogene’s expression from resistance to tyrosine kinase inhibitors (TKIs). Thus, we retrospectively examined BCR-ABL1 evolution in 305 chronic-phase CML patients receiving imatinib mesylate (IM) as a first line treatment. Patients were subdivided in two groups: those with a confirmed rise in BCR-ABL1 transcripts without MR3.0 loss and those failing IM. We found that the DTs of the former patients were significantly longer than those of patients developing IM resistance (57.80 vs. 41.45 days, p = 0.0114). Interestingly, the DT values of individuals failing second-generation (2G) TKIs after developing IM resistance were considerably shorter than those observed at the time of IM failure (27.20 vs. 41.45 days; p = 0.0035). We next wanted to establish if decreases in BCR-ABL1 transcripts would identify subjects likely to obtain deep molecular responses. We therefore analyzed the BCR-ABL1 halving-times (HTs) of a different cohort comprising 174 individuals receiving IM in first line and observed that, regardless of the time point selected for our analyses (6, 12, or 18 months), HTs were significantly shorter in subjects achieving superior molecular responses (p = 0.002 at 6 months; p < 0.001 at 12 months; p = 0.0099 at 18 months). Moreover, 50 patients receiving 2G TKIs as first line therapy and obtaining an MR3.0 (after 6 months; p = 0.003) or an MR4.0 (after 12 months; p = 0.019) displayed significantly shorter HTs than individuals lacking these molecular responses. Our findings suggest that BCR-ABL1 DTs and HTs are reliable tools to, respectively, identify subjects in MR3.0 that are failing their assigned TKI or to recognize patients likely to achieve deep molecular responses that should be considered for treatment discontinuation
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