Design, construction, and test of the Gas Pixel Detectors for the IXPE mission

Due to be launched in late 2021, the Imaging X-Ray Polarimetry Explorer (IXPE) is a NASA Small Explorer mission designed to perform polarization measurements in the 2-8 keV band, complemented with imaging, spectroscopy and timing capabilities. At the heart of the focal plane is a set of three polarization-sensitive Gas Pixel Detectors (GPD), each based on a custom ASIC acting as a charge-collecting anode. In this paper we shall review the design, manufacturing, and test of the IXPE focal-plane detectors, with particular emphasis on the connection between the science drivers, the performance metrics and the operational aspects. We shall present a thorough characterization of the GPDs in terms of effective noise, trigger efficiency, dead time, uniformity of response, and spectral and polarimetric performance. In addition, we shall discuss in detail a number of instrumental effects that are relevant for high-level science analysis -- particularly as far as the response to unpolarized radiation and the stability in time are concerned.Comment: To be published in Astroparticle Physic

LARES is in orbit! Some aspects of the mission

LARES (LAser RElativity Satellite), a scientific satellite of the Italian Space Agency (ASI), has been accurately injected in the nominal orbit by the new ESA expendable launch vehicle, Vega during its qualification launch, on the 13th of February 2012. This was a very exciting result also because of the low success rate of qualification launches . Furthermore, several innovative technical solutions characterize the new European launch vehicle, such as the extensive use of carbon fiber reinforced plastic composites for the rocket structures. LARES program started on February 2008 when the Italian Space Agency awarded a contract to the prime contractor CGS (former Carlo Gavazzi Space). A peculiarity of the LARES program was the extensive involvement of universities in many aspects such as the technical design of the satellite and the innovative separation system. A strong cooperation between ASI and ESA about its respective programs, since the acceptance of the LARES mission for the Vega maiden flight, allowed to design a mission which satisfies the scientific requirements of the satellite along with the launcher qualification objectives. The trajectory itself was defined also taking into account the launch vehicle performance and trajectory constraints. The initial orbit envisaged for the maiden flight was a typical sun-synchronous orbit at about 750 km. However that was not acceptable for the science objectives, i.e., the measurement of the Lense-Thirring effect, an Einstein general relativity prediction. Therefore ESA and the launch vehicle authority, ELV (European Launch Vehicle) Prime Contractor of the VEGA development program, proposed a new orbit at 1200 km that later was changed to 1450 km along with small changes to the inclination in order to comply with all the safety constraints to the mission trajectory. In order to meet part of its qualification requirements, the VEGA upper-stage (AVUM) performed several maneuvers, especially during the ballistic phase, namely: the neutral axis maneuver, the barbeque, sun pointing, and spin axis maneuver. In this paper, an overview of the LARES mission and of its elements, including the payload ground segment, is given, together with the first results of the launch campaign and activities that brought the satellite in the final operative configuration

LARES in orbit: some aspects of the mission

LARES (LAser RElativity Satellite), a scientific satellite of the Italian Space Agency (ASI), has been accurately injectcd in the nominal orbit by the new ESA expendable launch vehicle, Vega during its qualification launch, on the 13,h of February 2012. This was a very exciting result also because of the low success rate of qualification launches . Furthermore, several innovative technical solutions characterize the new European launch vehicle, such as the extensive use of carbon fiber reinforced plastic composites for the rocket structures. LARES program started on February 2008 when the Italian Space Agency awarded a contract to the prime contractor CGS (former Carlo Gavazzi Space). A peculiarity of the LARES program was the extensive involvement of universities in many aspects such as the technical design of the satellite and the innovative separation system. A strong cooperation between ASI and ESA about its respective programs, since the acceptance of the LARES mission for the Vega maiden flight, allowed to design a mission which satisfies the scientific requirements of the satellite along with the launchcr qualification objectives. The trajectory itself was defined also taking into account the launch vehicle performance and trajectory constraints. The initial orbit envisaged for the maiden flight was a typical sun-synchronous orbit at about 750 km. However that was not acceptable for the science objectives, i.e., the measurement of the Lense- Thirring effect, an Einstein general relativity prediction. Therefore ESA and the launch vehicle authority, ELV (European Launch Vehicle) Prime Contractor of the VEGA development program, proposed a new orbit at 1200 km that later was changed to 1450 km along with small changes to the inclination in order to comply with all the safety constraints to the mission trajectory. In order to meet part of its qualification requirements, the VEGA upper-stage (AVUM) performed several maneuvers, especially during the ballistic phase, namely: the neutral axis maneuver, the barbeque, sun pointing, and spin axis maneuver. In this paper, an overview of the LARES mission and of its elements, including the payload ground segment, is given, together with the first results of the launch campaign and activities that brought the satellite in the final operative configuration. Copyright © (2012) by the International Astronautical Federation

Immune Checkpoint Modulators: An Emerging Antiglioma Armamentarium

Immune checkpoints have come to the forefront of cancer therapies as a powerful and promising strategy to stimulate antitumor T cell activity. Results from recent preclinical and clinical studies demonstrate how checkpoint inhibition can be utilized to prevent tumor immune evasion and both local and systemic immune suppression. This review encompasses the key immune checkpoints that have been found to play a role in tumorigenesis and, more specifically, gliomagenesis. The review will provide an overview of the existing preclinical and clinical data, antitumor efficacy, and clinical applications for each checkpoint with respect to GBM, as well as a summary of combination therapies with chemotherapy and radiation

Enhanced anti-neuroblastoma activity of a fenretinide complexed form after intravenous administration

OBJECTIVES: The major limitation to successful chemotherapy of neuroblastoma (NB) is the toxicity and the poor bioavailability of traditional drugs. METHODS: We synthesised an amphiphilic dextrin derivative (DX-OL) able to host fenretinide (4-HPR) by complexation. In this study, we have investigated the effects of 4-HPR-loaded amphipilic dextrin (DX-OL/4-HPR) in comparison with 4-HPR alone both in vitro on human NB cells and in vivo in pseudometastatic NB models. The haemolysis assay was used as a measure of the potential damage caused by the pharmaceutical formulation in vivo. Pharmacokinetic experiments were performed to assess drug plasma levels in mice treated with free or complexed 4-HPR. KEY FINDINGS: DX-OL/4-HPR exerted a more potent cytotoxic activity on NB cells. Complexed 4-HPR significantly increased the proportion of sub-G1 cells with respect to free 4-HPR. Dextrin derivatives showed no haemolytic activity, indicating their suitability for parenteral administration. DX-OL/4-HPR increased the lifespan and the long-term survival of treated mice over controls. The analysis of drug plasma levels indicates that the complexed drug has a higher AUC due to a reduced clearance from the blood. CONCLUSIONS: Our data suggest that DX-OL/4-HPR is an injectable formulation that is able to improve drug aqueous solubility and bioavailability

LARES satellite and separation system.

The LARES satellite for the study of the Lense-Thirring effect predicted by Einstein general relativity has been launched on the 13th of February 2012 and injected in the nominal orbit with high accuracy. The Italian Space Agency (ASI) and the European Space Agency (ESA) provided the main support to the mission, ASI on the LARES system side and ESA on the launch vehicle side. An important requirement of the satellite was the lowest possible value of the surface-to-mass ratio. This is indeed related to the possibility to reduce the effect of classical surface perturbations on the satellite motion. That was achieved by constructing the highest mean density orbiting body in the solar system, that implied the use of a non conventional material for space. The experience acquired on the bulk tungsten material used for LARES, during the manufacturing of breadboards, improved the knowledge on the machining of this material that was never used, at least as a main component of a satellite and with this dimension, in the aerospace field. The knowledge acquired suggested some improvements in the manufacturing strategy for the Flight unit resulting in even tighter tolerances than in the demonstration unit. Also for the LARES separation system an unconventional design was adopted since no protruding parts were acceptable on the satellite surface. In the paper some detail on the manufacturing processes of LARES satellite will be reported and the final design of the separation system will be described along with some other relevant particular issues. Copyright © (2012) by the International Astronautical Federation

LARES satellite and separation system.

The LARES satellite for the study of the Lense-Thirring effect predicted by Einstein general relativity has been launched on the 13th of February 2012 and injected in the nominal orbit with high accuracy. The Italian Space Agency (ASI) and the European Space Agency (ESA) provided the main support to the mission, ASI on the LARES system side and ESA on the launch vehicle side. An important requirement of the satellite was the lowest possible value of the surface-to-mass ratio. This is indeed related to the possibility to reduce the effect of classical surface perturbations on the satellite motion. That was achieved by constructing the highest mean density orbiting body in the solar system, that implied the use of a non conventional material for space. The experience acquired on the bulk tungsten material used for LARES, during the manufacturing of breadboards, improved the knowledge on the machining of this material that was never used, at least as a main component of a satellite and with this dimension, in the aerospace field. The knowledge acquired suggested some improvements in the manufacturing strategy for the Flight unit resulting in even tighter tolerances than in the demonstration unit. Also for the LARES separation system an unconventional design was adopted since no protruding parts were acceptable on the satellite surface. In the paper some detail on the manufacturing processes of LARES satellite will be reported and the final design of the separation system will be described along with some other relevant particular issues