38 research outputs found

    Use of Radium-223 Dichloride in Patients With Osteonecrosis of the Jaw Induced by Zoledronic Acid: Report of 2 Cases.

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    Bisphosphonates, a group of inorganic pyrophosphate analogues that prevent the loss of bone density, are commonly used in patients with bone metastases; the calcium-mimetic a-emitter radium-223 dichloride (Ra223) is a bone-targeting therapy used in patients with metastatic castration-resistant prostate cancer (mCRPC)-related bone metastases. Both treatments reduce pain and disability; Ra223 is associated with significantly improved overall survival in mCRPC. Patients who receive bisphosphonate therapy are at risk of developing osteonecrosis of the jaw, especially in those who do not undergo an accurate oral evaluation and sanitation before the beginning of therapy, and in patients who present with conditions that facilitate the development of this problem, such as inadequate oral and dental care, lack of prophylactic antimicrobial mouth rinsing, patient comorbidity, or suboptimal suturing after tooth extraction. Although there is possible synergism between bisphosphonates and Ra223 therapy, there is no consensus about the use of Ra223 in patients with previous/current osteonecrosis of the jaw induced by zoledronic acid. However, our experience suggests that Ra223 therapy might not be contraindicated in patients with osteonecrosis of the jaw induced by zoledronic acid if an appropriate multidisciplinary approach is followed, and we report 2 cases of patients with current or previous osteonecrosis of the jaw induced by zoledronic acid, who were treated with Ra223 for mCRPCrelated bone metastases. Multidisciplinary management, including accurate clinical and radiological evaluation before beginning therapy with Ra223, together with oral sanitation and periodic controls during treatment, allowed successful administration of Ra223 while reducing side effects, with absent or minimal worsening of osteonecrosis

    Sequence randomness and polymer collapse transitions

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    Contrary to expectations based on Harris' criterion, chain disorder with frustration can modify the universality class of scaling at the theta transition of heteropolymers. This is shown for a model with random two-body potentials in 2D on the basis of exact enumeration and accurate Monte Carlo results. When frustration grows beyond a certain finite threshold, the temperature below which disorder becomes relevant coincides with the theta one and scaling exponents definitely start deviating from those valid for homopolymers.Comment: 4 pages, 4 eps figure

    Test-Driven Design of an Active Dual-Polarized Log-Periodic Antenna for the Square Kilometre Array

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    An active dual-polarized Log-Periodic antenna has been designed to meet the requirements of the low-frequency (50 - 350 MHz) radio telescope of the Square Kilometre Array (SKA). The integration of antenna and low noise amplifier has been conceived in order to achieve a high degree of testability. This aspect has been found to be crucial to obtain a smooth frequency response compatible with the SKA science cases. The design has also been driven by other factors such as the large-volume production (more than 130 000 antennas will be built) and the environmental conditions of the harsh Australian desert. A specific verification approach based on both wideband radiometric spectral and spatial measurements in relevant laboratory and in-situ conditions has been developed. Electromagnetic analyses and experimental results exhibit a very good agreement. In December 2019, this antenna was part of the reference solution for the System Critical Design Review of the SKA

    Моделирование магнетронной распылительной системы методом конечных элементов

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    В работе проведено моделирование магнетронной распылительной системы методом конечных элементов и методом Галеркина. Получены распределения концентрации и скоростей носителей заряда, распределение электрического потенциала и магнитного поля, рассмотрены временные зависимости физических величин. Разработано программное обеспечение для моделирования сложных физических задач. Проведена верификация расчетного алгоритма на примере решения модельных задач. Отличительной особенностью исследуемой модели от существующих является учет нестационарного и конвективного слагаемых в уравнении для переноса скорости электрона и максимально точная реализация всех слагаемых в дифференциальном уравнении (в рамках метода Галеркина).The dissertation examines the modeling of a magnetron sputtering system by finite element analysis and Galerkin method. The model makes it possible to calculate the concentration, velocity, temperature, electrical potential and magnetic field. The methods and the code developed according to the model are usable for modeling complex physical tasks. The work also includes analysis and verification of results

    Theta-point universality of polyampholytes with screened interactions

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    By an efficient algorithm we evaluate exactly the disorder-averaged statistics of globally neutral self-avoiding chains with quenched random charge qi=±1q_i=\pm 1 in monomer i and nearest neighbor interactions qiqj\propto q_i q_j on square (22 monomers) and cubic (16 monomers) lattices. At the theta transition in 2D, radius of gyration, entropic and crossover exponents are well compatible with the universality class of the corresponding transition of homopolymers. Further strong indication of such class comes from direct comparison with the corresponding annealed problem. In 3D classical exponents are recovered. The percentage of charge sequences leading to folding in a unique ground state approaches zero exponentially with the chain length.Comment: 15 REVTEX pages. 4 eps-figures . 1 tabl

    Electromagnetic modelling of the SKA-LOW AAVS2 prototype

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    The computational electromagnetic modelling of a large radio telescope prototype array for the Square Kilometer Array is described. The numerical models, using the Method of Moments, are characterised by a very large number of unknowns, requiring the use of fast solution methods and high performance computing platforms. Good agreement has been obtained between results obtained on two different commercial codes. Results for both embedded element patterns and the station beam are shown. The use of the computed embedded element patterns for array calibration is briefly addressed

    Report attività di didattica e divulgazione INAF-IRA 2021

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    In questo documento sono riportate e descritte le attività di Didattica e Divulgazione (D&D) dell'INAF - Istituto di Radioastronomia svolte nel 2021. Le attività includono la progettazione di contenuti, la curatela e gestione del Centro Visite “Marcello Ceccarelli”, l’organizzazione di eventi in collaborazione con enti territoriali, nazionali e internazionali, la gestione amministrativa e finanziaria, la formazione di studenti e giovani collaboratori e la gestione degli accessi esterni per riprese video e servizi fotografici presso la Stazione Radioastronomica di Medicina (BO)

    REPORT 2022 DELLE ATTIVITÀ DI DIDATTICA E DIVULGAZIONE INAF - IRA

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    L'Istituto di Radioastronomia (IRA) dell’Istituto Nazionale di Astrofisica (INAF) è impegnato nella diffusione delle proprie attività presso le scuole e il pubblico, attraverso le visite guidate alle Stazioni Radioastronomiche di Medicina (BO) e Noto (SR) e la partecipazione alla realizzazione di mostre, eventi, ecc. Le attività di Didattica e Divulgazione IRA includono la progettazione di contenuti, la curatela e gestione del Centro Visite “Marcello Ceccarelli”, l’organizzazione di eventi in collaborazione con enti territoriali, nazionali e internazionali, la gestione amministrativa e finanziaria, la formazione di nuovo personale. In questo documento sono riportate le attività svolte nel 2022

    A prototype model for evaluating SKA-LOW station calibration

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    The Square Kilometre Array telescope at low-frequency (SKA-Low) will be a phased array telescope supporting a wide range of science cases covering the frequency band 50 - 350 MHz, while at the same time asking for high sensitivity and excellent characteristics. These extremely challenging requirements resulted in a design using 512 groups of 256 log periodic dual polarized antennas each (where each group is called "station"), for a total of 131072 antennas. The 512 stations are randomly distributed mostly within a dense area around the centre of the SKA-Low, and then in 3 arms having 16 station clusters each. In preparation for the SKA Phase 1 (SKA1) System Critical Design Review (CDR), prototype stations were deployed at the Murchison Radio-astronomy Observatory (MRO) site (Western Australia) near the Murchison Widefield Array (MWA) radio telescope. The project involved multiple parties in an International collaboration building and testing different prototypes of the SKA1-Low station near the actual site. This resulted in both organisational and logistic challenges typical of a deployment of the actual telescope. The test set-up involved a phased build-up of the complex station of log-periodic antennas, by starting from the deployment of 48 antennas and related station signal processing (called AAVS1.5, where AAVS stands for Aperture Array Verification System), followed by expansion to a full station (AAVS2.0). As reference a station with dipole antennas EDA2 (EDA: Engineering Development Array) was deployed. This test set-up was used for an extensive test and evaluation programme. All test antenna configurations were simulated in detail by electromagnetic (EM) models, and the prediction of the models was further verified by appropriate tests with a drone-based radio frequency source. Astronomical observations on Sun and galaxy transit were performed with calibrated stations of both EDA2, AAVS1.5 and AAVS2.0. All 3 configurations were calibrated. EM modelling and calibration results for the full station AAVS2.0 and EM verification for the AAVS1.5 station are presented. The comparisons between the behaviour of the log-periodic antennas and the dipoles have advanced our understanding the calibration quality and the technological maturity of the future SKA1-Low array
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