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.
We present a compact and efficient electromagnetic source able to generate a 2-D Gaussian beam in a parallel-plate waveguide. The parallel-plate waveguide is a typical guiding structure used to ...experimentally test in a laboratory the electromagnetic behavior of a device under test in terms of propagation, transmission, and reflection. The most common launcher for this waveguide is a quarter-wavelength monopole, which generates a cylindrical wave. However, in order to approximate the cylindrical wave to a plane-wave impinging on the device under test, this launcher needs electrically large setups. The proposed solution makes use of a metallic bidimensional parabolic reflector, which is able to transform the cylindrical wave radiated by the conventional launcher into a plane wave with the Gaussian amplitude distribution. We demonstrate that this setup can dramatically reduce the dimensions of a conventional launcher for a given directivity (i.e., planarity of the generated phase fronts). The optimum design and the experimental verification of the proposed compact launcher are presented.
Introduction Hypersexuality is an uncommon behavioral complication associated with traumatic brain injury (TBI) involving lesions to frontal basal, temporal, or diencephalic structures. Experimental ...brain injury in animals has produced hypersexual behaviors; however, there is comparative paucity of knowledge in humans. TBI with hypersexuality offers insights into neurological basis of aberrant sexual behaviors as well as potential treatments. This case report describes social/sexual disinhibition in a patient following neurosurgery for self-inflicted TBI. Method Case analysis with literature review. Results 32-year-old male was admitted with TBI following an unsuccessful suicide attempt, self-inflicted nail gun injury to the occiput. CT scan revealed 6.5cm nail that had entered the skull in right occiput, right parasagittal location with nail head right of vein of Galen, coursing through splenium of corpus callosum, right thalamus-hypothalamus-midbrain, with its tip at the suprasellar cistern. Occipital craniotomy with retrieval of foreign body was performed eleven days after admission. From post-operative day eight through twenty-seven, patient made inappropriate sexual comments to female medical student: asking her out repetitively, describing her physical appearance, enquiring about her suitors, and requesting her to call him upon his discharge. Prior psychiatric history was pertinent for major depression and social anxiety (especially women) with psychotropic noncompliance. During admission, patient was diagnosed with recurrent major depression, social anxiety by history, and impulse control disorder nos. On sertraline titrated to 100mg qhs, depression resolved with increased control over newly acquired sexual/social disinhibition noted. Conclusion TBI can lead to social disinhibition and hypersexuality. Sertraline may be a beneficial treatment.
To characterize the clinical presentation of pediatric patients who, upon AM diagnosis, also had imaging-diagnosed ICCs (ID-ICCs); to define the group of AM patients at risk of developing ID-ICCs; ...and to update knowledge about organisms causing AM.
Analysis of all AM patients admitted between 1997 and 2018 and treated according to an obligatory protocol including both brain imaging and sampling for bacterial culture upon clinical diagnosis of AM.
Of 166 admitted patients (0.5–19 years old) 22 (13%) already had ID-ICCs. In patients who, on admission, had already received antibiotics for acute otitis media (AOM) and also had CRP (C-reactive protein) levels above 93.5 mg/L, the risk of ID-CC was increased by 22.5-fold (P < 0.0001). Bacterial culture results were available for all patients and were positive in 115 (69%). Organisms most commonly found in patients without prior antibiotic treatment were group A Streptococcus pyogenes (53%), Streptococcus pneumoniae (23%), and Haemophylus influenzae (11%), while with prior antibiotic treatment they were Fusobacterium necrophorum (21%), Streptococcus pyogenes (18%) and Pseudomonas aeruginosa (18%).
Since the risk of ID-ICC in patients with the abovementioned CRP and prior antibiotic treatment was significantly higher than in the others, these high-risk patients should undergo diagnostic imaging on admission. Antibiotic treatment prior to AM development may promote growth of non-AOM pathogen.
Fructoselysine 3-phosphate is synthesized in vivo by the recently discovered fructoseamine-3-kinase (F3K) from fructoselysine and ATP and decomposes to lysine, P(i) and 3-deoxyglucosone (3DG). This ...pathway appears to dominate 3DG production in vivo, making it possible to modulate 3DG levels by stimulating or inhibiting the reaction. Present inhibitors are non-reacting substrate analogues with relatively high K (i) values and can inhibit F3K sufficiently in vivo to reduce 3DG in diabetic rat plasma by approx. 50%. Stimulation of the F3K pathway by feeding glycated casein causes an increase of 10-20-fold in plasma levels of 3DG and 3-fold in kidney tubules. Consequences of this increase were studied in two systems: the Eker rat, a model of susceptible kidney tubules; and birth rates in two rat strains. In both cases substantial pathological effects were observed. In the Eker rats, an approx. 3-fold increase in kidney lesions was observed ( P <0.00001). In both Fischer 344 and Sprague-Dawley rats, birth rates were reduced by 56% ( P <0.0001) and 12% ( P <0.015) respectively. These results suggest that inhibition of F3K is a promising new therapeutic target for diabetic complications, as well as other 3DG-dependent pathologies.
Radiation-induced effects on the RIGEL ASIC Ceraudo, F.; Dedolli, I.; Cirrincione, D. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2022, Letnik:
1037
Journal Article
Recenzirano
This paper describes the radiation tests performed on the RIGEL, the Application-Specific Integrated Circuit (ASIC) designed within the scope of the PixDD project, whose goal is the production of a ...multi-pixel silicon-based detector system to be placed at the focal plane of X-ray optics on board space astronomy missions. Carried out at the RADiation Effects Facility of the University of Jyväskylä (Finland), the campaign aimed at studying the response of the ASIC to radiation damage, in the form of both Total Ionising Dose and Single Event Effects, especially latch-ups and bit upsets. Experimental results were then combined with simulations of the space environment for a low-inclination equatorial orbit and for a Sun-synchronous orbit. The analysis shows that the device under study may be safely operated on an equatorial orbit without any circuitry to protect it from transient radiation phenomena, whereas the need of such a precaution is necessary in the case of a Sun-synchronous orbit. According to the experimental results, the degradation due to Total Ionising Dose, measured in terms of Equivalent Noise Charge, stays below 10% up to 34krad, implying that it can be managed or neglected altogether for the simulated orbits.
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