The High Energy Modular Ensemble of Satellites (HERMES) project is aimed to realize a modular X/gamma-ray monitor for transient events, to be placed on-board of a nano-satellite bus (e.g. CubeSat). ...This expandable platform will achieve a significant impact on Gamma Ray Burst (GRB) science and on the detection of Gravitational Wave (GW) electromagnetic counterparts: the recent LIGO/VIRGO discoveries demonstrated that the high-energy transient sky is still a field of extreme interest. The very complex temporal variability of GRBs (experimentally verified up to the millisecond scale) combined with the spatial and temporal coincidence between GWs and their electromagnetic counterparts suggest that upcoming instruments require sub-microsecond time resolution combined with a transient localization accuracy lower than a degree. The current phase of the ongoing HERMES project is focused on the realization of a technological pathfinder with a small network (3 units) of nano-satellites to be launched in mid 2020. We will show the potential and prospects for short and medium-term development of the project, demonstrating the disrupting possibilities for scientific investigations provided by the innovative concept of a new “modular astronomy” with nano-satellites (e.g. low developing costs, very short realization time). Finally, we will illustrate the characteristics of the HERMES Technological Pathfinder project, demonstrating how the scientific goals discussed are actually already reachable with the first nano-satellites of this constellation. The detector architecture will be described in detail, showing that the new generation of scintillators (e.g. GAGG:Ce) coupled with very performing Silicon Drift Detectors (SDD) and low noise Front-End-Electronics (FEE) are able to extend down to few keV the sensitivity band of the detector. The technical solutions for FEE, Back-End-Electronics (BEE) and Data Handling will be also described.
The satellite LARES 2 is designed to test dragging of inertial frames, or frame-dragging, predicted by Einstein’s theory of General Relativity, with accuracy of a few parts in a thousand. For this ...purpose, besides the typical requirements for a space construction, a high density alloy must be used. In this paper are reported the studies performed on a nickel alloy, the Haynes 242, that is considered a possible candidate for manufacturing all the metallic parts of LARES 2 and other passive geodetic satellites. Haynes 242 density and mechanical properties are compliant with the requirements of the mission. Three different casting with the nominal composition of the alloy have been prepared and tested along with a commercial bar of Haynes 242. The results of tensile and hardness tests on several specimens with different aging time are reported, along with the relevant metallographic analysis. Furthermore, a test on the machinability, performed on a screw, which is the most demanding item from the manufacturing point of view, is reported.
A new compound LaSrCu
0.4
Al
0.6
O
4−
δ
has been prepared by sol gel method, annealed at 1623 K in oxygen gas flow and examined by X-ray diffraction. Rietveld refinement shows that the sample adopts ...the K
2
NiF
4
-type structure, space group I4/mmm (
a
= 3.7694(2) and
c
= 12.8248(5) Ǻ,
Z
= 2). Vibrational properties were investigated using Raman scattering and the most characteristic vibrations are discussed with reference to the available structural data. Differential thermal analysis shows two endothermic effects at 329 and 593 K and one exothermic at 693 K. Dielectric study as a function of temperature in the frequency range of 1 kHz–1 MHz has confirmed the observed phase transitions. The value of the measured dielectric constant depends on the frequency and undergoes a large increase near the phase transition temperatures indicating a diffuse behavior of these transitions. Variation of conductivity as a function of temperature shows that the compound has a semiconducting behavior. Oxygen vacancies could be the possible ionic charge carriers. The electrical transport mechanism agrees with Adiabatic Small Polaron Hopping model.
The aim of this study was to evaluate crestal bone resorption and bone apposition resulting from immediate post-extraction implants in the canine mandible, comparing a conditioned sandblasted ...acid-etched implant surface with a non-conditioned standard sandblasted implant surface.
In this experimental study, third and fourth premolars and distal roots of first molars were extracted bilaterally from six Beagle dog mandibles. Each side of the mandible received three assigned dental implants, with the conditioned surface (CS) on the right side and the non-conditioned surface (NCS) on the left. The dogs were sacrificed at 2 (n=2), 4 (n=2) and 12 weeks (n=2) after implant placement.
The microscopic healing patterns at 2, 4 and 12 weeks for both implant types (CS and NCS) yielded similar qualitative bone findings. The mean crestal bone resorption was found to be greater for all implants with NCS (2.28+/-1.9 mm) than CS (1.21+/-1.05 mm) at 12 weeks. The mean percentage of newly formed bone in contact with implants was greater in implants CS (44.67+/-0.19%) than with the NCS (36,6+/-0.11%). There was less bone resorption with the CS than the NCS.
The data show significantly more bone apposition (8% more) and less crestal bone resorption (1.07 mm) with the CS than with the NCS after 12 weeks of healing. This CS can reduce the healing period and increase bone apposition in immediate implant placements.
Objective
To evaluate gonadal function and uterine volume in a cohort of female survivors treated by chemotherapy, radiotherapy, and/or stem cell transplantation (SCT) for childhood malignant and ...non‐malignant diseases.
Design
An observational study.
Setting
S. Matteo Hospital, Pavia, Italy.
Population
A cohort of 135 female survivors.
Methods
A clinical, hormonal, and ultrasonographic evaluation. Thirty‐three patients (24%) had non‐malignant haematologic diseases (thalassaemia or sickle cell anaemia), 68 (50%) had leukaemia, 23 (17%) had lymphomas, and 11 (8%) had solid tumours. In total, 106 patients had received SCT, preceded by a conditioning regimen.
Main outcome measures
Anti‐Müllerian hormone (AMH) and Inhibin–B, and uterine volume.
Results
The median concentrations of AMH and Inhibin–B in the entire cohort were 0.12 ng/ml (interquartile range, IQR, 0.1–0.5 ng/ml) and 3.5 pg/ml (IQR 0.1–13.2 pg/ml), respectively. In a stepwise ordered logistic regression analysis, conventional chemotherapy for the treatment of malignancies, as opposed to total body irradiation (TBI), was the only oncologically significant predictor of increased AMH levels (OR 4.8, 95% CI 1.9–12, P < 0.001). Conditioning treatment before or after menarche did not influence AMH concentrations (P = 0.24). The best predictor of reduced uterine volume was TBI during the preparation for the allograft (OR 3.5, 95% CI 1.4–8.4, P = 0.006). Increasing age at treatment (OR 0.86, 95% CI 0.77–0.95, P = 0.04), chemotherapy, as opposed to other treatments (OR 0.09, 95% CI 0.03–0.28, P < 0.001), and solid tumours as opposed to either leukaemia/lymphomas or non‐malignant diseases (OR 0.2, 95% CI 0.07–0.56, P = 0.002) were associated with larger uterine volumes.
Conclusions
Conditioning therapies for SCT, including TBI, had the worst effects on uterine volume and gonadal reserve. Increasing age at treatment and conventional chemotherapy were associated with less detrimental effects on uterine volume.
GrailQuest (Gamma Ray Astronomy International Laboratory for QUantum Exploration of Space-Time) is a mission concept based on a constellation (hundreds/thousands) of nano/micro/small-satellites in ...low (or near) Earth orbits. Each satellite hosts a non-collimated array of scintillator crystals coupled with Silicon Drift Detectors with broad energy band coverage (keV-MeV range) and excellent temporal resolution (≤ 100 nanoseconds) each with effective area ∼100cm2. This simple and robust design allows for mass-production of the satellites of the fleet. This revolutionary approach implies a huge reduction of costs, flexibility in the segmented launching strategy, and an incremental long-term plan to increase the number of detectors and their performance; this will result in a living observatory for next-generation, space-based astronomical facilities. GrailQuest is conceived as an all-sky monitor for fast localisation of high signal-to-noise ratio transients in the X-/gamma-ray band, e.g. the elusive electromagnetic counterparts of gravitational wave events. Robust temporal triangulation techniques will allow unprecedented localisation capabilities, in the keV-MeV band, of a few arcseconds or below, depending on the temporal structure of the transient event. The ambitious ultimate goal of this mission is to perform the first experiment, in quantum gravity, to directly probe space-time structure down to the minuscule Planck scale, by constraining or measuring a first-order dispersion relation for light in vacuo. This is obtained by detecting delays between photons of different energies in the prompt emission of Gamma-Ray Bursts.
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