937 research outputs found

    On the morphology of Anisakis pegreffii: a comparative analysis of three microscopic techniques used to build a new parasite atlas

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    BACKGROUND: Human anisakidosis is a parasitic anthropozoonosis caused by larval nematodes of the family Anisakidae. Here, we report a detailed description of the morphology of Anisakis pegreffii third-stage larva performed using a conventional light and confocal microscopy, and scanning electron microscopy (SEM) that provide a basis for both phenotypic studies and genetic mutations. METHODS: The collected larvae from fish were morphologically identified as Anisakis larvae Type I, and they were characterized by PCR-RFLP to identify the Anisakis pegreffii specie. Using NC5/NC2 primers, ribosomal genomic regions ITS1, 5.8 SrRNA and ITS2 of DNA were amplified and PCR products were sequenced. Fifteen larvae belonging to Anisakis pegreffii were fixed, sectioned, and examined with a light and confocal microscope and by SEM. RESULTS: In our studies, have been acquired detailed ultrastructural images, which have been integrated with those derived from the dissection of the parasite, obtained with light and confocal microscopy. The structural and ultrastructural images concerning the third stage larvae of Anisakis pegreffii have been studied, analyzed and compared among them. The derived overall view has allowed detecting new interesting details of a well-known parasite and has been schematically showed. CONCLUSIONS: The aim of this study is to furnish an updated atlas of Anisakis pegreffii. Confocal microscopy, as well as the light and electron microscopy have played a pivotal role in the accumulation of new scientific data regarding the anatomical structures of this nematode. This work is the result of one year of engagement by the Authors and the outcome is a comprehensive atlas on Anisakis pegreffii microscopy

    Theoretical Uncertainties in Red Giant Branch Evolution: The Red Giant Branch Bump

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    A Monte Carlo simulation exploring uncertainties in standard stellar evolution theory on the red giant branch of metal-poor globular clusters has been conducted. Confidence limits are derived on the absolute V-band magnitude of the bump in the red giant branch luminosity function (M_v,b) and the excess number of stars in thebump, R_b. The analysis takes into account uncertainties in the primordial helium abundance, abundance of alpha-capture elements, radiative and conductive opacities, nuclear reaction rates, neutrino energy losses, the treatments of diffusion and convection, the surface boundary conditions, and color transformations. The uncertainty in theoretical values for the red giant bump magnitude varies with metallicity between +0.13/-0.12 mag at [Fe/H] = -2.4 and +0.23/-0.21 mag at [Fe/H] = -1.0.Thedominantsourcesofuncertaintyaretheabundanceofthealpha−captureelements,themixinglength,andthelow−temperatureopacities.ThetheoreticalvaluesofMv,bareingoodagreementwithobservations.TheuncertaintyinthetheoreticalvalueofRbis+/−0.01atallmetallicitiesstudied.Thedominantsourcesofuncertaintyaretheabundanceofthealpha−captureelements,themixinglength,andthehigh−temperatureopacities.ThemedianvalueofRbvariesfrom0.44at[Fe/H]=−2.4. The dominant sources of uncertainty are the abundance of the alpha-capture elements, the mixing length, and the low-temperature opacities. The theoretical values of M_v,b are in good agreement with observations. The uncertainty in the theoretical value of R_b is +/-0.01 at all metallicities studied. The dominant sources of uncertainty are the abundance of the alpha-capture elements, the mixing length, and the high-temperature opacities. The median value of R_b varies from 0.44 at [Fe/H] = -2.4 to 0.50 at [Fe/H] = -1.0. These theoretical values for R_b are in agreement with observations.Comment: 30 pages, 6 figures. To appear in Ap

    The Age Dependent Luminosities of the Red Giant Branch Bump, Asymptotic Giant Branch Bump, and Horizontal Branch Red Clump

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    Color-magnitude diagrams of globular clusters often exhibit a prominent horizontal branch (HB) and may also show features such as the red giant branch (RGB) bump and the asymptotic giant branch (AGB) bump. Stellar evolution theory predicts that the luminosities of these features will depend on the metallicity and age of the cluster. We calculate theoretical lines of 2 to 12 Gyr constant age RGB-bumps and AGB-bumps in the V(HB-Bump)--[Fe/H] diagram, which shows the brightness difference between the bump and the HB as a function of metallicity. In order to test the predictions, we identify giant branch bumps in new Hubble Space Telescope color-magnitude diagrams for 8 SMC clusters. First, we conclude that the SMC cluster bumps are RGB-bumps. The data for clusters younger than ~6 Gyr are in fair agreement the relative age dependent luminosities of the HB and RGB-bump. The V(HB-Bump)--[Fe/H] data for clusters older then ~6 Gyr demonstrate a less satisfactory agreement with our calculations. We conclude that ~6 Gyr is a lower bound to the age of clusters for which the Galactic globular cluster, age independent V(HB-Bump)--[Fe/H] calibration is valid. Application of the V(HB-bump)--[Fe/H] diagram to stellar population studies is discussed.Comment: Accepted for publication in the Astrophysical Journal, 30 pages, Latex aaspp4.sty, including 7 postscript figure

    The shape of the Red Giant Branch Bump as a diagnostic of partial mixing processes in low-mass stars

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    We suggest to use the shape of the Red Giant Branch (RGB) Bump in metal-rich globular clusters as a diagnostic of partial mixing processes between the base of the convective envelope and the H-burning shell. The Bump located along the differential luminosity function of cluster RGB stars is a key observable to constrain the H-profile inside these structures. In fact, standard evolutionary models that account for complete mixing in the convective unstable layers and radiative equilibrium in the innermost regions do predict that the first dredge-up lefts over a very sharp H-discontinuity at the bottom of the convective region. Interestingly enough we found that both atomic diffusion and a moderate convective overshooting at the base of the convective region marginally affects the shape of the RGB Bump in the differential Luminosity Function (LF). As a consequence, we performed several numerical experiments to estimate whether plausible assumptions concerning the smoothing of the H-discontinuity, due to the possible occurrence of extra-mixing below the convective boundary, affects the shape of the RGB Bump. We found that the difference between the shape of RGB Bump predicted by standard and by smoothed models can be detected if the H-discontinuity is smoothed over an envelope region whose thickness is equal or larger than 0.5 pressure scale heights. Finally, we briefly discuss the comparison between theoretical predictions and empirical data in metal-rich, reddening free Galactic Globular Clusters (GGCs) to constrain the sharpness of the H-profile inside RGB stars.Comment: 15 pages, 8 postscript figures, ApJ in pres

    Behavioral and clinical characteristics of people receiving medical care for HIV infection in an outpatient facility in Sicily, Italy

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    Aim: The authors examined a cohort of HIV-positive outpatients at the AIDS Center of Palermo University in Italy in order to identify factors related to the frequency of their visits to the outpatient facility for health care services. Methods: Two hundred and twenty-four HIV-infected subjects were enrolled in the study. Demographic and HIV disease characteristics were recorded and assessed with the number of days accessed to our outpatients unit in univariate and multivariate analyses. The potential relationship with immunological status was also analyzed stratifying the patients into groups according to their CD4+ T-cell counts ( 65500 vs, \u2c2500/mm3, and 65200 vs < 200/mm3). Results: Both univariate and multivariate analyses showed that duration of antiretroviral therapy, \u2c25 years and hypertension were significantly associated with a CD4+ T-cell count of, \u2c2500/mm3, whereas geographic origin (Africa) was associated with a CD4+ T-cell count of, \u2c2200/mm3. Mean number of days the patients sought access to day-care services for laboratory tests was negatively associated with CD4+ T-cell count. Conclusion: Patients with low CD4+ T-cell counts showed higher use of health care services, demonstrating how early HIV diagnosis can help to reduce health care costs. The CD4+ T-cell cut-off of 200 cells emphasizes the importance of identifying and managing HIV infection among hard-to-reach groups like vulnerable migrants. In our sle, the illegal status of immigrants does not influence the management of their HIV/AIDS condition, but the lack of European health card that documents the current antiretroviral status, could interfere with the efforts to eradicate AIDS. A better understanding of the major determinants of HIV treatment costs has led to appropriate large-scale actions, which in turn has increased resources and expanded intervention programs. Further guidance should be offered to hard-to-reach groups in order to improve early AIDS diagnosis, and procedures for identifying and managing these vulnerable subjects should be made available to care commissioners and service providers

    18F-FDG PET-Derived Volume-Based Parameters to Predict Disease-Free Survival in Patients with Grade III Breast Cancer of Different Molecular Subtypes Candidates to Neoadjuvant Chemotherapy

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    We investigated whether baseline [F-18] Fluorodeoxyglucose (F-18-FDG) positron emission tomography (PET)-derived semiquantitative parameters could predict disease-free survival (DFS) in patients with grade III breast cancer (BC) of different molecular subtypes candidate to neoadjuvant chemotherapy (NAC). For each F-18-FDG-PET/CT scan, the following parameters were calculated in the primary tumor (SUVmax, SUVmean, MTV, TLG) and whole-body (WB_SUVmax, WB_MTV, and WB_TLG). Receiver operating characteristic (ROC) analysis was used to determine the capability to predict DFS and find the optimal threshold for each parameter. Ninety-five grade III breast cancer patients with different molecular types were retrieved from the databases of the University Hospital of Padua and the University Hospital of Ferrara (luminal A: 5; luminal B: 34; luminal B-HER2: 22; HER2-enriched: 7; triple-negative: 27). In luminal B patients, WB_MTV (AUC: 0.75; best cut-off: WB_MTV &gt; 195.33; SS: 55.56%, SP: 100%; p = 0.002) and WB_TLG (AUC: 0.73; best cut-off: WB_TLG &gt; 1066.21; SS: 55.56%, SP: 100%; p = 0.05) were the best predictors of DFS. In luminal B-HER2 patients, WB_SUVmax was the only predictor of DFS (AUC: 0.857; best cut-off: WB_SUVmax &gt; 13.12; SS: 100%; SP: 71.43%; p &lt; 0.001). No parameter significantly affected the prediction of DFS in patients with grade III triple-negative BC. Volume-based parameters, extracted from baseline F-18-FDG PET, seem promising in predicting recurrence in patients with grade III luminal B and luminal B- HER2 breast cancer undergoing NAC

    Intermediate mass stars: updated models

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    A new set of stellar models in the mass range 1.2 to 9 M⊙M_{\odot} is presented. The adopted chemical compositions cover the typical galactic values, namely 0.0001≀Z≀0.020.0001 \le Z \le 0.02 and 0.23≀Y≀0.280.23 \le Y \le 0.28. A comparison among the most recent compilations of similar stellar models is also discussed. The main conclusion is that the differencies among the various evolutionary results are still rather large. For example, we found that the H-burning evolutionary time may differ up to 20 %. An even larger disagreement is found for the He-burning phase (up to 40-50 %). Since the connection between the various input physics and the numerical algorithms could amplify or counterbalance the effect of a single ingredient on the resulting stellar model, the origin of this discrepancies is not evident. However most of these discrepancies, which are clearly found in the evolutionary tracks, are reduced on the isochrones. By means of our updated models we show that the ages inferred by the theory of stellar evolution is in excellent agreement with those obtained by using other independent methods applied to the nearby Open Clusters. Finally, the theoretical initial/final mass relation is revised.Comment: 35 pages, 24 figures, 4 tables, accepted for publication in the Astrophisycal Journa

    Improving Mechanical Properties and Reaction to Fire of EVA/LLDPE Blends for Cable Applications with Melamine Triazine and Bentonite Clay

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    The high flame-retardant loading required for ethylene-vinyl acetate copolymer blends with polyethylene (EVA-PE) employed for insulation and sheathing of electric cables represents a significant limitation in processability and final mechanical properties. In this work, melamine triazine (TRZ) and modified bentonite clay have been investigated in combination with aluminum trihydroxide (ATH) for the production of EVA-PE composites with excellent fire safety and improved mechanical properties. Optimized formulations with only 120 parts per hundred resin (phr) of ATH can achieve self-extinguishing behavior according to the UL94 classification (V0 rating), as well as reduced combustion kinetics and smoke production. Mechanical property evaluation shows reduced stiffness and improved elongation at break with respect to commonly employed EVA-PE/ATH composites. The reduction in filler content also provides improved processability and cost reductions. The results presented here allow for a viable and halogen-free strategy for the preparation of high performing EVA-PE composites

    MALFORMATIONS OF CENTRAL NERVOUS SYSTEM: GENERAL ISSUES

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    Malformations of the central nervous system (CNS) encompass a heterogeneous group of congenital anomalies that may be isolated or appear as part of a genetic syndrome. Advances in identifying the genetic etiology underlying many CNS malformation and syndromes have led to the current genetic-based classifications that allows us to better estimate prognosis and potential complications. Herein, we discuss the main genetic, clinical and radiological features and their implications for diagnostic testing and disease managemen
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