Silicon Photomultipliers (SiPMs) are semiconductor photosensors employed in a wide spectrum of scientific, medical and industrial applications when fast time response and faint light sensitivity in ...the infrared-ultraviolet range are required. With respect to the well-established technology of photomultiplier tube sensors, SiPMs feature improved spectral sensitivity, robust and customizable mechanical properties and higher resilience and flexibility for operation in harsh environments. These properties make SiPMs an enabling candidate technology to replace photomultiplier tubes and improve the performances of the instrumentation in the field of astrophysics. Many of next generation instruments for imaging cameras of ground-based telescope arrays and for spaceborne detectors for the inspection of the high energy sky are in fact considering SiPMs as the default photodetection technology both for direct and indirect photon detection. We review the most recent advances in the development of SiPM-based instruments for applications that are of interest for the frontier research in astrophysics from ground-based and spaceborne detectors.
The China Seismo-Electromagnetic Satellite (CSES) aims to monitor electromagnetic, particle, and plasma perturbations in the iono-magnetosphere and inner Van Allen radiation belts originated by ...electromagnetic sources external and internal to the geomagnetic cavity, cosmic rays, and solar events. In particular, the objective of the space mission is to investigate lithosphere-atmosphere-ionosphere coupling mechanisms (including the effects of lightning, earthquakes, volcanoes, and artificial electromagnetic emissions) that induce perturbations of the top side of the ionosphere and lower boundary of the radiation belts. To this purpose, the mission has been conceived to take advantage of a multi-instrument payload comprising nine detectors for the measurement of electromagnetic field components, plasma parameters, and energetic particles, as well as X-ray flux. The Italian team participating in the CSES mission has built one of these devices, the High-Energy Particle Detector (HEPD), for high-precision observations of electrons, protons, and light nuclei. During its trip along the orbit, and thanks to the large set of detectors operated on board, CSES completely monitors the Earth, acting as an excellent instrument for space weather. The satellite was launched on 2018 February 2, with an expected life span of 5 yr. This article describes the CSES mission with a particular focus on the HEPD apparatus and its in-flight performance.
Abstract
Commonly used in structural applications since the ’90s, composite materials represent a valid alternative to metallic solutions. An intense research activity accompanied the spread of this ...technology to the point that, nowadays, a large variety of modeling techniques and tools are at the designers’ disposal. Although the literature on this topic is vast, detailed, and thorough, the need for new, faster, and more efficient design tools and methodologies remains. In this context, this work covers the development of an Open-Source computational laminate analysis toolbox, its structure, and its validation. The objective of the research was the creation of a simple and accessible mean for the calculation of laminates’ stresses in complex structural components with a reduced computational cost. To this end, the authors implemented the basics of micro, meso, and micromechanics in a Python-based toolbox and then performed a validation campaign against the results of an FE analysis. The work resulted in an input-generation/output-analysis instrument to be used by designers alongside the FEA.
Abstract Mitochondrial dysfunction has long been implicated in the pathogenesis of Parkinson's disease (PD). PD brain tissues show evidence for mitochondrial respiratory chain Complex I deficiency. ...Pharmacological inhibitors of Complex I, such as rotenone, cause experimental parkinsonism. The cytoprotective protein DJ-1, whose deletion is sufficient to cause genetic PD, is also known to have mitochondria-stabilizing properties. We have previously shown that DJ-1 is over-expressed in PD astrocytes, and that DJ-1 deficiency impairs the capacity of astrocytes to protect co-cultured neurons against rotenone. Since DJ-1 modulated, astrocyte-mediated neuroprotection against rotenone may depend upon proper astrocytic mitochondrial functioning, we hypothesized that DJ-1 deficiency would impair astrocyte mitochondrial motility, fission/fusion dynamics, membrane potential maintenance, and respiration, both at baseline and as an enhancement of rotenone-induced mitochondrial dysfunction. In astrocyte-enriched cultures, we observed that DJ-1 knock-down reduced mitochondrial motility primarily in the cellular processes of both untreated and rotenone treated cells. In these same cultures, DJ-1 knock-down did not appreciably affect mitochondrial fission, fusion, or respiration, but did enhance rotenone-induced reductions in the mitochondrial membrane potential. In neuron–astrocyte co-cultures, astrocytic DJ-1 knock-down reduced astrocyte process mitochondrial motility in untreated cells, but this effect was not maintained in the presence of rotenone. In the same co-cultures, astrocytic DJ-1 knock-down significantly reduced mitochondrial fusion in the astrocyte cell bodies, but not the processes, under the same conditions of rotenone treatment in which DJ-1 deficiency is known to impair astrocyte-mediated neuroprotection. Our studies therefore demonstrated the following new findings: (i) DJ-1 deficiency can impair astrocyte mitochondrial physiology at multiple levels, (ii) astrocyte mitochondrial dynamics vary with sub-cellular region, and (iii) the physical presence of neurons can affect astrocyte mitochondrial behavior.
Esophagectomy has high cardiac and pulmonary complication rates that can reach 43% and 58% respectively. The original Ivor Lewis esophagectomy was a two-stage procedure. We revisited this procedure ...using a hybrid minimally-invasive approach.
Thirty-five consecutive patients with esophageal cancer were operated on over an eight-year period. The first stage used laparoscopic mobilization of the stomach, while the second stage used open thoracotomy. Six patients were aborted due to unresectable disease.
Twenty-nine patients were studied. The mean operative times for stage-one and stage-two were 108 ± 18 and 226 ± 63 min respectively. All patients were extubated in the operating room. One (3.4%) patients had cardiac complication and one (3.4%) patient had pulmonary complication.
Metachronous hybrid two-stage esophagectomy was associated with a low rate of cardio-pulmonary complications. It may be considered as an alternative to the one-stage esophagectomy, especially in low-volume centers, to decrease these high-risk cardio-pulmonary complications.
•The two-stage esophagectomy may decrease the high risk post-op cardiopulmonary complications in a low volume hospital.•The two-day ischemic conditioning of the stomach may have contributed to decreasing leak rate.•Total hospital length of stay (LOS) in this two-stage procedure is similar to LOS reported in single-stage esophagectomy.
The FOOT (FragmentatiOn Of Target) experiment aims to measure the fragmentation cross-section of protons into H, C, O targets at beam energies of interest for hadrontherapy (50-250 MeV for H and ...50-400 MeV/u for C ions).
Given the short range of the fragments, an inverse kinematic approach requiring precise tracking capabilities in a magnetic volume has been chosen.
A key subsystem of this experiment will be the Microstrip Silicon Detector, based on 3 X-Y measuring station, each composed of two 150
μm
thick single side microstrip sensors. In this work, we present the results of characterization of the new version of a 64 channel low-noise/low power high dynamic range readout ASIC and subsequent tests of the first 150 um thick sensor prototype.
A series of tests were also performed to validate a novel “grazing angle” approach, where it is possible to change the track length below a given strip varying the incoming particle’s incident angle onto the sensor to test the electronics dynamic range without using high Z ions.
Following the decision to maintain the International Space Station (ISS) on orbit until at least 2020 (possibly until 2028) the AMS collaboration decided to correspondingly extend the lifetime of the ...experiment. Since the limited amount of helium used to cool the superconducting magnet allowed for only a limited run time of the experiment, a change from the superconducting magnet to the permanent magnet used in AMS-01 became necessary. Due to the lower magnetic field, to maintain the resolution the silicon tracker also had to be reconfigured with the installation of a silicon plane on the top of the experiment and a new plane above the electromagnetic calorimeter.
In the last few years a number of efforts have been undertaken to develop new technology related to Silicon Photomultipliers (SiPMs). These photosensors consist of an array of identical Avalanche ...Photodiodes operating in Geiger mode and connected in parallel to a single output. The Italian Institute of Nuclear Physics (INFN) is involved in the R&D program Progetto Premiale Telescopi CHErenkov made in Italy (TECHE.it) to develop photosensors for a SiPM based camera that will be part of the Cherenkov Telescope Array (CTA) observatory. In this framework tests are ongoing on innovative devices suitable to detect Cherenkov light in the blue and near-UV wavelength region, the so-called Near Ultra-Violet Silicon Photomultipliers (NUV SiPMs). The tests on photosensors produced by Fondazione Bruno Kessler (FBK) are revealing promising performance: low operating voltage, capability to detect very low intensity light down to a single photon and high Photo Detection Efficiency (PDE) in the range 390–410nm. In particular the developed device is a High Density NUV-SiPM (NUV-HD SiPM) based on a micro-cell of 30μm×30μm and 6mm×6mm area. Tests on this detector in single-cell configuration and in a matrix arrangement have been done. At the same time front-end electronics based on the waveform sampling technique optimized for the new NUV-HD SIPMs is under study and development.
Single-walled carbon nanotubes (SWNTs) due to their unique structural and physicochemical properties, have been proposed as delivery systems for a variety of diagnostic and therapeutic agents. ...However, SWNTs have proven difficult to solubilize in aqueous solution, limiting their use in biological applications. In an attempt to improve SWNTs' solubility, biocompatibility, and to increase cell penetration we have thoroughly investigated the construction of carbon scaffolds coated with aliphatic carbon chains and phospholipids to obtain micelle-like structures. At first, oxidized SWNTs (2370 ± 30 nmol mg(-1) of SWNTs) were covalently coupled with an alcoholic chain (stearyl alcohol, C(18)H(37)OH; 816 nmol mg(-1) of SWNTs). Subsequently, SWNTs-COOC(18)H(37) derivatives were coated with phosphatidylethanolamine (PE) or -serine (PS) phospholipids obtaining micelle-like structures. We found that cellular uptake of these constructs by phagocytic cells occurs via an endocytotic mechanism for constructs larger than 400 nm while occurs via diffusion through the cell membrane for constructs up to 400 nm. The material that enters the cell by phagocytosis is actively internalized by macrophages and localizes inside endocytotic vesicles. In contrast the material that enters the cells by diffusion is found in the cell cytosol. In conclusion, we have realized new biomimetic constructs based on alkylated SWNTs coated with phospholipids that are efficiently internalized by different cell types only if their size is lower than 400 nm. These constructs are not toxic to the cells and could now be explored as delivery systems for non-permeant cargoes.
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