474 research outputs found

    Neutron Star Radius-to-mass Ratio from Partial Accretion Disc Occultation as Measured through Fe Kα\alpha Line Profiles

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    We present a new method to measure the radius-to-mass ratio (R/M) of weakly magnetic, disc-accreting neutron stars by exploiting the occultation of parts of the inner disc by the star itself. This occultation imprints characteristic features on the X-ray line profile that are unique and are expected to be present in low mass X-ray binary systems seen under inclinations higher than ~65 degrees. We analyse a NuSTAR observation of a good candidate system, 4U 1636-53, and find that X-ray spectra from current instrumentation are unlikely to single out the occultation features owing to insufficient signal-to-noise. Based on an extensive set of simulations we show that large-area X-ray detectors of the future generation could measure R/M to ~2{\div}3% precision over a range of inclinations. Such is the precision in radius determination required to derive tight constraints on the equation of state of ultradense matter and it represents the goal that other methods too aim to achieve in the future.Comment: 17 pages, 8 figures; this is a pre-print edition of an article that has been accepted for publication in the Astrophysical Journa

    Sublingual immunotherapy in children: facts and needs

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    Allergen specific immunotherapy (SIT) is the practice of administering gradually increasing doses of the specific causative allergen to reduce the clinical reactivity of allergic subjects, and is the only treatment targeting the causes of hypersensitivity and not only the symptoms, as done by drugs. The traditional, subcutaneous immunotherapy (SCIT) was burdened by the problem of systemic reactions which may be sometimes severe and - though very rarely - even fatal. This was the background to develop non injections routes for SIT and particularly sublingual immunotherapy (SLIT), that emerged as a real treatment option for respiratory allergy

    Design of an Innovative Graphite Exchanger for Adsorption Heat Pumps and Chillers

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    Abstract In this work, an innovative adsorber for application in adsorption heat pumps and chillers is presented. The adsorber consists of several assembled graphite plates and the flow path of heat transfer fluid. Each plate consists of a process side (where zeolite is deposited onto) and a heat transfer fluid (HTF) side where liquid water flows. The resulting adsorbent heat exchanger is able to deliver about 0.5-1 kW cooling power and possesses attractive thermo physical properties, especially in term of low weight, volume and thermal capacity. Experimental testing of the full-scale adsorber by a testing station available at CNR ITAE is currently ongoing

    Navigated Antral Bone Expansion (NABE): a prospective study on 35 patients with 4 months of follow-up post implant loading

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    The insertion of dental implants in the atrophic posterior maxilla can be a challenge. One option is to modify the residual native bone in preparation for proper, prosthetically-driven implant placement. The procedure presented in this study is called Navigated Antral Bone Expansion (N.A.B.E). This procedure employs the use of a navigation system to plan and guide the initial pilot drilling, bone expansion, final site preparation, and implant insertion. The aim of this study was to compare the distance between the alveolar ridge and the sinus floor measured before and after the surgery performed using the N.A.B.E.Methods: Thirty-seven partially edentulous patients who were candidates for implant supported restoration in the posterior maxilla, with a bone height ranging from 4 to 7 mm were enrolled. The N.A.B.E procedure was used to increase the bone height. Paired-samples t-test evaluated the distance between the alveolar ridge and the sinus floor measured before and after surgery. The occurrence of post-surgical complications, and the angular deviation between the planned osteotomy and the actual placed implant trajectories were evaluated. Results: Out of the 37 consecutive patients enrolled in the study, 35 were considered in the data analyses. Patients' bone height after surgery compared to the bone height before surgery showed a statistically significant increase (p < .0005) of 3.96 mm (95% CI, 3.62 mm to 4.30 mm). No post-operative complications were observed in the 35 patients. The mean angular deviation between the planned osteotomy trajectory and the placed implant trajectory ranged between 12.700 to 34.900 (mean 25.170 ± 5.100). Conclusions: This study provides evidence that N.A.B.E. technique is able to provide a significant bone increase, and could be considered an alternative method to the management of the atrophic posterior maxilla with a minimally invasive approach

    Hepatitis B vaccination failure in children with Diabetes Mellitus? The debate continues

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    The aim of our study was to evaluate the presence of specific antibodies against HBsAg in diabetic children (IDDM) previously vaccinated against hepatitis B virus.110 diabetic children were retrospectively studied and 100 healthy controls were recruited. In all patients surface antigen, HBV core IgG, antibodies against HBV "e" antigen and quantitative HBV surface antibodies were detected. In 45 patients molecular typing of HLA alleles was performed. Metabolic control was evaluated as mean glycated hemoglobin (HbA1c) and all patients were compliant to insulin therapy.46 of 110 diabetic children (41.8%) and 16 of 100 healthy controls (16%) were found to have not anti-HBs antibodies (p0.0001). The mean antibody titer was found significantly-lower (p0.0001) in IDDM children than healthy controls. No correlation was found between antibody titer, age, duration of disease and HbA1c. We did not find any difference of gender, age, years of onset of the disease and metabolic control, between diabetics with anti-HBs antibodies and those without.Our data confirm the reduced seroprotection rate for HBV vaccination in diabetics. However it remains poorly clarify the real clinical significance of this result. In our study no diabetic children showed markers of HBV infection

    Root-end resection with or without retrograde obturation after orthograde filling with two techniques: A micro-CT study

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    To evaluate the filling ability of two orthograde obturation techniques followed by the apical resection with or without retrograde obturation through micro-computed tomography (CT). Thirty-two single-rooted permanent teeth were prepared and randomised into four groups (n = 8) according to the orthograde obturation technique (single cone technique [SCT] and mineral trioxide aggregate placement) combined or not with retrograde obturation. The volume of voids (VoV) within the entire endodontic space, the apical 3 mm, and 1 mm after root resection was calculated by micro-CT. Statistical analysis showed no significant difference among the groups regarding the total VoV in all root canals, as well as within the apical 1 mm after root resection. The SCT and apical resection without retrograde filling showed significantly better results in terms of VoV at the apical 3 mm after root resection. Within the study limitations, SCT associated with apical resection without retrograde preparation exhibited a similar or less amount of voids than the other groups

    Pentaerythritol and Glycerol Esters Derived from Gum Rosin as Bio-Based Additives for the Improvement of Processability and Thermal Stability of Polylactic Acid

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    [EN] Gum rosin esters are some of the most common gum rosin derivatives used in different applications, such as coatings, paper, varnishes, chewing gum, and food industries. In this study, gum rosin esters are used as additives for polylactic acid (PLA) to improve its processability and thermal stability. Blends of an amorphous PLA with two different gum rosin esters, pentaerythritol ester and glycerol ester, were prepared by melt extrusion process in concentrations from 1, 3, and 5 phr. Besides the comparison of thermal degradation, microstructure assessment, and melt flow index (MFI) analysis, the processability performance during testing samples production by injection molding process was evaluated. Experimental results showed that MFI values of PLA-gum rosin ester blends increased by 100%, 147%, and 164%, along with increasing content of gum rosin esters addition, in both cases. Also, both derivatives slightly improved PLA thermal stability (around 3ÂşC higher). Injection molding temperature decreased by at least 20 Â°C for PLA-gum rosin ester blends compared with neat PLA. Furthermore, the maximum tensile strength of PLA-gum rosin esters was negligibly affected in formulations with low content of gum rosin esters, and the FESEM images revealed a good dispersion and compatibility of gum rosin ester particles into PLA matrix in both concentrations.This research was funded by MCIN/AEI/10.13039/501100011033 through PID-AEI Project (grant PID2021-123753NA-C33 and PID2020-116496RB-C22) and TED-AEI Project (grants TED2021-129920 A-C43), and, as appropriate, by "ERDF A way of making Europe", by the "European Union" or by the "European Union NextGenerationEU/PRTR".Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature.Rosa-RamĂ­rez, HDL.; Dominici, F.; Ferri, J.; Luzi, F.; Puglia, D.; Torre, L.; LĂłpez-MartĂ­nez, J.... (2023). Pentaerythritol and Glycerol Esters Derived from Gum Rosin as Bio-Based Additives for the Improvement of Processability and Thermal Stability of Polylactic Acid. Journal of Polymers and the Environment. 31(12):5446-5461. https://doi.org/10.1007/s10924-023-02949-054465461311

    Shaping ability of Procodile and R6 Reziflow nickel-titanium reciprocating instruments in curved mesial root canals of mandibular molars: A MicroCT study

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    To compare the shaping ability of Procodileand R6 Reziflow instruments used in reciprocating motion in severely curved root canals, assessed with micro-computed tomography (mu CT). Fourteen extracted human mandibular first molars were randomly assigned to two instrumentation techniques (n = 14 mesial root canals): Procodile or R6 Reziflow. For both groups, root canals were prepared to the working length up to a size 25,.06 taper. Molars were virtually divided into apical, middle and coronal thirds and mu CT was used to scan all samples pre- and post-root canal. Canal transportation, centring ability, volume, surface area and unprepared area were evaluated. Geometrical parameter changes were compared with preoperative values (one-way analyses of variance and Tukey multiple comparison post-hoc test) between groups and Student t-test within groups (alpha = 0.05) Significantly less transportation was observed associated with the Procodile technique in the molar's coronal third compared to the R6 Reziflow technique (p <.05). No significant differences in root canal centring ability, volume, surface area and unprepared area were observed. Procodile showed a lower percentage increase of surface area compared to R6 Reziflow (p <.05). The Procodile and R6 Reziflow techniques applied to first molar root canal performed similarly except for the less transportation observed in the coronal third using Procodile.Research Highlights MicroCT analysis of canal geometry before and after instrumentation revealed that Procodile and R6 Reziflow showed a similar shaping ability to shape curved root canals without substantially modifications of the original tooth anatomy
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