Context. The mini-calorimeter (MCAL) instrument on-board the AGILE satellite is a non-imaging gamma-ray scintillation detector sensitive in the 300 keV–100 MeV energy range with a total on-axis ...geometrical area of 1400 cm2. Gamma-ray bursts (GRBs) are one of the main scientific targets of the AGILE mission and the MCAL design as an independent self-triggering detector makes it a valuable all-sky monitor for GRBs. Furthermore MCAL is one of the very few operative instruments with microsecond timing capabilities in the MeV range. Aims. In this paper the results of GRB detections with MCAL after one year of operation in space are presented and discussed. Methods. A flexible trigger logic implemented in the AGILE payload data-handling unit allows the on-board detection of GRBs. For triggered events, energy and timing information are sent to telemetry on a photon-by-photon basis, so that energy and time binning are limited by counting statistics only. When the trigger logic is not active, GRBs can be detected offline in ratemeter data, although with worse energy and time resolution. Results. Between the end of June 2007 and June 2008 MCAL detected 51 GRBs, with a detection rate of about 1 GRB/week, plus several other events at a few milliseconds timescales. Since February 2008 the on-board trigger logic has been fully active. Comparison of MCAL detected events and data provided by other space instruments confirms the sensitivity and effective area estimations. MCAL also joined the 3rd Inter-Planetary Network, to contribute to GRB localization by means of triangulation.
We sought to further validate the novel vasoactive-ventilation-renal (VVR) score in a prospective study of a heterogeneous cohort of children undergoing cardiac surgery that includes patients with ...single-ventricle anatomy and residual mixing lesions.
We prospectively performed an observational study of all children less than 18 years of age who underwent surgery for congenital heart disease at our center from November 2013 to June 2014. We calculated VVR score as follows: vasoactive-inotrope score + ventilation index + (change in serum creatinine from baseline × 10). Admission, peak, and 48-hour measurements were recorded. Outcomes of interest were prolonged duration of mechanical ventilation and intensive care unit and hospital stays, represented by the upper 25% for all patients. Areas under the receiver-operating characteristic curves (AUC) were determined for all study timepoints and outcome variables.
Ninety-two patients were analyzed; their median age was 0.65 (range, 3 days to 17.9 years), and 17 (18%) had single-ventricle anatomy. The VVR measurements outperformed vasoactive-inotrope scores in isolation at all timepoints, with higher AUC values for all outcomes. Of the three timepoints assessed, the 48-hour VVR score most consistently predicted poor outcome, especially with regard to prolonged duration of mechanical ventilation (AUC 0.980) and prolonged intensive care unit stay (AUC 0.919).
In a heterogeneous population of children undergoing cardiac surgery, the 48-hour VVR score was a very strong predictor of outcomes, and outperformed the more traditional vasoactive-inotrope score. The VVR score, therefore, represents a novel and potentially powerful means of predicting clinical outcomes relatively early in the hospital course of these patients.
Characterization of a tagged beam line at the Beam Test Facility Cattaneo, P W; Argan, A; Boffelli, F ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2012, Letnik:
674
Journal Article
Recenzirano
At the core of the AGILE scientific instrument, designed to operate on a satellite, there is the Gamma Ray Imaging Detector (GRID) consisting of a Silicon Tracker (ST), a Cesium Iodide ...Mini-Calorimeter and an Anti-Coincidence system of plastic scintillator bars. The ST needs an on-ground calibration with a gamma - ray beam to validate the simulation used to calculate the energy response function and the effective area versus the energy and the direction of the gamma rays. A tagged gamma - ray beam line was designed at the Beam Test Facility (BTF) of the INFN Laboratori Nazionali of Frascati (LNF), based on an electron beam generating gamma - rays through bremsstrahlung in a position-sensitive target. The gamma - ray energy is deduced by difference with the post-bremsstrahlung electron energy 1,2. The electron energy is measured by a spectrometer consisting of a dipole magnet and an array of position sensitive silicon strip detectors, the Photon Tagging System (PTS). The use of the combined BTF-PTS system as tagged photon beam requires understanding the efficiency of gamma - ray tagging, the probability of fake tagging, the energy resolution and the relation of the PTS hit position versus the gamma - ray energy. This paper describes this study comparing data taken during the AGILE calibration occurred in 2005 with simulation.
Objective To determine the prevalence of and risk factors for extrathoracic upper-airway obstruction after pediatric cardiac surgery. Study design A retrospective chart review was performed on 213 ...patients younger than 18 years of age who recovered from cardiac surgery in our multidisciplinary intensive care unit in 2012. Clinically significant upper-airway obstruction was defined as postextubation stridor with at least one of the following: receiving more than 2 corticosteroid doses, receiving helium-oxygen therapy, or reintubation. Multivariate logistic regression analysis was performed to determine independent risk factors for this complication. Results Thirty-five patients (16%) with extrathoracic upper-airway obstruction were identified. On bivariate analysis, patients with upper-airway obstruction had greater surgical complexity, greater vasoactive medication requirements, and longer postoperative durations of endotracheal intubation. They also were more difficult to calm while on mechanical ventilation, as indicated by greater infusion doses of narcotics and greater likelihood to receive dexmedetomidine or vecuronium. On multivariable analysis, adjunctive use of dexmedetomedine or vecuronium (OR 3.4, 95% CI 1.4-8) remained independently associated with upper-airway obstruction. Conclusion Extrathoracic upper-airway obstruction is relatively common after pediatric cardiac surgery, especially in children who are difficult to calm during endotracheal intubation. Postoperative upper-airway obstruction could be an important outcome measure in future studies of sedation practices in this patient population.
Children undergoing cardiac surgery may receive corticosteroids preoperatively to temper cardiopulmonary bypass-related inflammation, postoperatively for hemodynamic instability, and periextubation ...to reduce airway edema. Recent data have associated preoperative corticosteroids with infection. We aimed to determine if there is a relationship between cumulative corticosteroid exposure and infection.
A retrospective review of children who underwent cardiac surgery at our institution from January 2009 to July 2010 was performed. To limit study heterogeneity, patients who were 5 years or younger with basic Aristotle score of 7 or higher and intensive care unit stay of 7 days or more were included. Infections during the first 30 postoperative days were recorded, defined as clinically relevant positive blood, urine, respiratory, or wound cultures, or culture-negative sepsis treated with 7 or more days of antimicrobial therapy. Multivariate logistic regression analysis was performed to determine independent risk factors for infection.
Seventy-six patients were reviewed. All patients received intraoperative methylprednisolone, 48% received postoperative hydrocortisone, and 86% received periextubation dexamethasone. Twenty-six patients (36%) had 58 infections. On univariate analysis, patients with infection had greater median comprehensive Aristotle score (14.5 intraquartile range (IQR): 12.5 to 16 versus 11.5 IQR: 10 to 13.1, p = 0.001), maximum vasoactive inotrope score (29 IQR: 24 to 40 versus 24 IQR: 17 to 31, p = 0.031, days endotracheally intubated (12 IQR: 7 to 30 versus 5 IQR: 4 to 6.5, p < 0.001), and days of corticosteroid exposure (7 IQR: 5 to 12 versus 4 IQR: 2 to 5), p < 0.001). Also, patients with infections more often underwent delayed sternal closure (p = 0.008). On multivariate analysis, days endotracheally intubated (p = 0.023) and days of corticosteroid exposure (p = 0.015) remained significant.
For children undergoing complex cardiac surgery, greater cumulative duration of corticosteroid exposure is independently associated with postoperative infection.
Preliminary results on TeV sources search with AGILE Rappoldi, A.; Longo, F.; Argan, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2011, Letnik:
630, Številka:
1
Journal Article
Recenzirano
During its first 2 years of operation, the gamma-ray AGILE satellite almost completed a full study of the gamma-ray sky. This paper presents the preliminary results of the systematic study performed ...on the AGILE data to search for GeV counterparts and to derive flux upper limits of the TeV sources detected by various instruments (MAGIC, HESS, VERITAS, Cangaroo, MILAGRO, ARGO,
…
.).
An X-ray imager based on silicon microstrip detector and coded mask Del Monte, E.; Costa, E.; Di Persio, G. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
06/2007, Letnik:
576, Številka:
1
Journal Article
Recenzirano
SuperAGILE is the X-ray monitor of AGILE, a satellite mission for gamma-ray astronomy, and it is the first X-ray imaging instrument based on the technology of the silicon microstrip detectors ...combined with a coded aperture imaging technique. The SuperAGILE detection plane is composed of four 1-D silicon microstrip detector modules, mechanically coupled to tungsten coded mask units. The detector strips are separately and individually connected to the input analogue channels of the front-end electronics, composed of low-noise and low-power consumption VLSI ASIC chips. SuperAGILE can produce 1-D images with 6 arcmin angular resolution and ∼2–3 arcmin localisation capability, for intense sources, in a field of view composed of two orthogonal areas of 107°×68°. The time resolution is 2
μs, the overall dead time is ∼5
μs and the electronic noise is ∼7.5
keV full-width at half-maximum. The resulting instrument is very compact (40×40×14
cm
3), light (10
kg) and has low power consumption (12
W). AGILE is a mission of the Agenzia Spaziale Italiana and its launch is planned in 2007 in a low equatorial Earth orbit. In this contribution we present SuperAGILE and discuss its performance and scientific objectives.
The flaring blazars of the first 1.5 years of the AGILE mission Pacciani, L.; Bulgarelli, A.; Chen, A.W. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2011, Letnik:
630, Številka:
1
Journal Article
Recenzirano
Odprti dostop
We report the AGILE
γ
-ray
observations and the results of the multiwavelength campaigns on seven flaring blazars detected by the mission: During two multiwavelength campaigns, we observed
γ
-ray
...activity from two Flat Spectrum Radio Quasars of the Virgo region, e.g. 3C 279 and 3C 273 (the latter being the first extragalactic source simultaneously observed with the
γ
-ray
telescope and the hard X ray imager of the mission). Due to the large FOV of the AGILE/GRID instrument, we achieved an almost continuous coverage of the FSRQ 3C 454.3. The source showed flux above 10
−6 photons/cm
2/s (
E
>
100
MeV
) and showed day by day variability during all the AGILE observing periods. In the EGRET era, the source was found in high
γ
-ray
activity only once. An other blazar, PKS 1510-089 was frequently found in high
γ
-ray
activity. S5 0716+71, an intermediate BL Lac object, exhibited a very high
γ
-ray
activity and fast
γ
-ray
variability during a period of intense optical activity. We observed high
γ
-ray
activity from W Comae, a BL Lac object, and Mrk 421, a high energy peaked BL Lac object. For this source, a multiwavelength campaign from optical to TeV has been performed.
Objective To assess emergency department (ED) utilization and physician preparedness for infants with single ventricle (SV) physiology between stage 1 and stage 2 surgical palliation. Study design ...Records of infants with SV physiology discharged after stage I palliation between July 2006 and June 2009 were retrospectively reviewed. Next, a cross-sectional survey of registered ED physicians in Michigan was performed. Results Thirty-three of 42 patients (79%) required 65 ED visits, most commonly presenting with respiratory distress (35%). Six patients died in the ED; 35 other visits resulted in hospital admission, 4 requiring urgent surgery or catheterization. Median initial hospital stay in those with ED visits was significantly longer (21 days; IQR, 17-45 days) than those without (12 days; IQR, 5.5-24 days) ( P = .032). Three hundred seventy-six of 915 surveyed ED physicians responded. Most (72%) were unsure of the acceptable range of arterial oxygen saturation for these infants, and 58% felt “uncomfortable” or “worried” about their treatment. Despite these concerns, 59% deemed education in SV physiology as low priority. Conclusions Between stages I and II, infants with SV physiology utilized the ED frequently, often with high disease acuity. Most ED physicians surveyed appeared underprepared for these infants. These findings underscore the need for educational efforts aimed at increasing ED preparedness.
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