Position resolution and particle identification with the ATLAS EM calorimeter

In the years between 2000 and 2002 several pre-series and series modules of the ATLAS EM barrel and end-cap calorimeter were exposed to electron, photon and pion beams. The performance of the calorimeter with respect to its finely segmented first sampling has been studied. The polar angle resolution has been found to be in the range 50-60 mrad/sqrt(E (GeV)). The neutral pion rejection has been measured to be about 3.5 for 90% photon selection efficiency at pT=50 GeV/c. Electron-pion separation studies have indicated that a pion fake rate of (0.07-0.5)% can be achieved while maintaining 90% electron identification efficiency for energies up to 40 GeV.Comment: 32 pages, 22 figures, to be published in NIM

Energy Linearity and Resolution of the ATLAS Electromagnetic Barrel Calorimeter in an Electron Test-Beam

A module of the ATLAS electromagnetic barrel liquid argon calorimeter was exposed to the CERN electron test-beam at the H8 beam line upgraded for precision momentum measurement. The available energies of the electron beam ranged from 10 to 245 GeV. The electron beam impinged at one point corresponding to a pseudo-rapidity of eta=0.687 and an azimuthal angle of phi=0.28 in the ATLAS coordinate system. A detailed study of several effects biasing the electron energy measurement allowed an energy reconstruction procedure to be developed that ensures a good linearity and a good resolution. Use is made of detailed Monte Carlo simulations based on Geant which describe the longitudinal and transverse shower profiles as well as the energy distributions. For electron energies between 15 GeV and 180 GeV the deviation of the measured incident electron energy over the beam energy is within 0.1%. The systematic uncertainty of the measurement is about 0.1% at low energies and negligible at high energies. The energy resolution is found to be about 10% sqrt(E) for the sampling term and about 0.2% for the local constant term

Improving resolution of public health surveillance for human Salmonella enterica serovar Typhimurium infection: 3 years of prospective multiple-locus variable-number tandem-repeat analysis (MLVA)

<p>Abstract</p> <p>Background</p> <p>Prospective typing of <it>Salmonella enterica </it>serovar Typhimurium (STM) by multiple-locus variable-number tandem-repeat analysis (MLVA) can assist in identifying clusters of STM cases that might otherwise have gone unrecognised, as well as sources of sporadic and outbreak cases. This paper describes the dynamics of human STM infection in a prospective study of STM MLVA typing for public health surveillance.</p> <p>Methods</p> <p>During a three-year period between August 2007 and September 2010 all confirmed STM isolates were fingerprinted using MLVA as part of the New South Wales (NSW) state public health surveillance program.</p> <p>Results</p> <p>A total of 4,920 STM isolates were typed and a subset of 4,377 human isolates was included in the analysis. The STM spectrum was dominated by a small number of phage types, including DT170 (44.6% of all isolates), DT135 (13.9%), DT9 (10.8%), DT44 (4.5%) and DT126 (4.5%). There was a difference in the discriminatory power of MLVA types within endemic phage types: Simpson's index of diversity ranged from 0.109 and 0.113 for DTs 9 and 135 to 0.172 and 0.269 for DTs 170 and 44, respectively. 66 distinct STM clusters were observed ranging in size from 5 to 180 cases and in duration from 4 weeks to 25 weeks. 43 clusters had novel MLVA types and 23 represented recurrences of previously recorded MLVA types. The diversity of the STM population remained relatively constant over time. The gradual increase in the number of STM cases during the study was not related to significant changes in the number of clusters or their size. 667 different MLVA types or patterns were observed.</p> <p>Conclusions</p> <p>Prospective MLVA typing of STM allows the detection of community outbreaks and demonstrates the sustained level of STM diversity that accompanies the increasing incidence of human STM infections. The monitoring of novel and persistent MLVA types offers a new benchmark for STM surveillance.</p> <p>A part of this study was presented at the MEEGID × (Molecular Epidemiology and Evolutionary Genetics of Infectious Diseases) Conference, 3-5 November 2010, Amsterdam, The Netherlands</p

Successful Versus Failed Transition From Controlled Ventilation to Pressure Support Ventilation in COVID-19 Patients: A Retrospective Cohort Study

Objectives: In patients with COVID-19 respiratory failure, controlled mechanical ventilation (CMV) is often necessary during the acute phases of the disease. Weaning from CMV to pressure support ventilation (PSV) is a key objective when the patient's respiratory functions improve. Limited evidence exists regarding the factors predicting a successful transition to PSV and its impact on patient outcomes. Design: Retrospective observational cohort study. Setting: Twenty-four Italian ICUs from February 2020 to May 2020. Patients: Mechanically ventilated ICU patients with COVID-19-induced respiratory failure. Intervention: The transition period from CMV to PSV was evaluated. We defined it as "failure of assisted breathing" if the patient returned to CMV within the first 72 hours. Measurements and main results: Of 1260 ICU patients screened, 514 were included. Three hundred fifty-seven patients successfully made the transition to PSV, while 157 failed. Pao2/Fio2 ratio before the transition emerged as an independent predictor of a successful shift (odds ratio 1.00; 95% CI, 0.99-1.00; p = 0.003). Patients in the success group displayed a better trend in Pao2/Fio2, Paco2, plateau and peak pressure, and pH level. Subjects in the failure group exhibited higher ICU mortality (hazard ratio 2.08; 95% CI, 1.42-3.06; p &lt; 0.001), an extended ICU length of stay (successful vs. failure 21 +/- 14 vs. 27 +/- 17 d; p &lt; 0.001) and a longer duration of mechanical ventilation (19 +/- 18 vs. 24 +/- 17 d, p = 0.04). Conclusions: Our study emphasizes that the Pao2/Fio2 ratio was the sole independent factor associated with a failed transition from CMV to PSV. The unsuccessful transition was associated with worse outcomes

Salmonella Strains Isolated from Galápagos Iguanas Show Spatial Structuring of Serovar and Genomic Diversity

It is thought that dispersal limitation primarily structures host-associated bacterial populations because host distributions inherently limit transmission opportunities. However, enteric bacteria may disperse great distances during food-borne outbreaks. It is unclear if such rapid long-distance dispersal events happen regularly in natural systems or if these events represent an anthropogenic exception. We characterized Salmonella enterica isolates from the feces of free-living Galápagos land and marine iguanas from five sites on four islands using serotyping and genomic fingerprinting. Each site hosted unique and nearly exclusive serovar assemblages. Genomic fingerprint analysis offered a more complex model of S. enterica biogeography, with evidence of both unique strain pools and of spatial population structuring along a geographic gradient. These findings suggest that even relatively generalist enteric bacteria may be strongly dispersal limited in a natural system with strong barriers, such as oceanic divides. Yet, these differing results seen on two typing methods also suggests that genomic variation is less dispersal limited, allowing for different ecological processes to shape biogeographical patterns of the core and flexible portions of this bacterial species' genome

Deterioration of lung function in a Pig Model of uncontrolled cardiac death

Introduction. Uncontrolled donors after circulatory determination of death (uDCDD) represent a yet unexplored pool of organs potentially available for transplantation. The aims of this study were to validate a protocol of cardiac death in the pig and to investigate lung function during the process. Materials and Methods. Cardiac death was induced in preanesthetized animals with an injection of 600 mg propofol; once systolic blood pressure was <50 mm Hg (Agonal Phase), a 20 mEq bolus of KCI was given and, after asystolia was documented, cardiopulmonary resuscitation (CPR) started, followed by 5 minutes no touch (end-CPR). Invasive blood pressure (BP) and heart rate (HR) were recorded; blood samples taken at baseline, 15 minutes after CPR, and after the no touch period (end-CPR). Computed tomography (CT) scans were taken at baseline and at end-CPR. Results. Agonal phase was reached in 6 +/- 1 minutes and lasted 3 +/- 1 minutes; average HR was 49 +/- 16 beats/min, and BP was 41 +/- 12 mm Hg. CPR lasted 35 +/- 3 minutes; average HR and BP were 113 +/- 32 beats/min and 86 +/- 63 mm Hg, respectively. PaO2/FiO(2) decreased from 442 +/- 31 mm Hg at baseline to 63 +/- 36 at end-CPR (P < .001). pH decreased from 7.378 +/- 0.045 to 6.931 +/- 0.042 (P < .001), with a corresponding increase of lactate from 0.9 +/- 0.2 to mmol/L to 12.8 +/- 2.1 (P < .001). As assessed using CT scan, total lung volume decreased (baseline vs end-CPR 1107 106 +/- mL vs 617 +/- 95; P < .001), whereas noninflated tissue (ie, atelectasis) significantly increased (46 +/- 10 g vs 131 +/- 89; P = .008). Conclusions. Lung function greatly deteriorated after cardiac death. The model we set may constitute a reproducible platform for future investigations on lung uDCDD

Indication to ECMO during lung transplantation

Introduction: We studied the use of mean systemic-to-pulmonary pressure ratio (MAP/mPAP) to stratify the need of ECMO during lung transplantation. Methods: Subjects were stratified according to MAP/mPAP ratio measured over a 10 minutes pulmonary artery (PA) clamp test. Subjects with a ratio below (Low) or above (High) the median value of MAP/mPAP (1.8 [1.5-2.4]) were analysed according to scheduling characteristics, intraoperative variables, and outcomes. Results: 24 LTXs were included in the analysis. mPAP increased from 30 [25-36] to 36 mmHg [29-44] (P<0.001), and MAP/mPAP decreased from 2.4 \ub1 0.7 to 2.2 \ub1 0.8 (P<0.001). All ECMOs were instituted in subjects of the Low group (8/12 vs. 0/12, Low vs. High, respectively, P<0.001). MAP/mPAP index was an independent predictor of ECMO (multiple logistic regression analysis P 0.002). Use of post-operative ECMO was greater in the Low group (P 0.037); primary graft dysfunction at 72 hours (PGD T72), ICU and hospital stay and 30-days survival were similar between groups. Of the Low group subjects (n=12), 3 had ECMO instituted immediately after PA clamp because of severe hemodynamic instability (ECMO), 4 never went on ECMO (no ECMO), 5 needed ECMO soon after graft reperfusion (delayed-ECMO). Subjects with delayed-ECMO had more PGD T72 (4 vs 1 vs 0; delayed-ECMO vs ECMO vs no-ECMO; P=0.051), despite similar donor and recipient characteristics. Conclusion: Intra-operative MAP/mPAP ratio at the time of PA clamp test is easy to obtain and useful to stratify the need of ECMO during LTx. To delay ECMO is harmful

Successful transplantation of lungs from an uncontrolled donor after circulatory death preserved in-situ by alveolar recruitment maneuvers and assessed by ex-vivo lung perfusion

We developed a protocol to procure lungs from uncontrolled donors after circulatory determination of death (NCT02061462). Subjects with cardiovascular collapse, treated on scene by a resuscitation team and transferred to the emergency room, are considered potential donors once declared dead. Exclusion criteria include un-witnessed collapse, no flow period of &gt;15 minutes, and low flow &gt;60 minutes. After death, lung preservation with recruitment maneuvers, Continuous Positive Airway Pressure (CPAP), and protective mechanical ventilation is applied to the donor. After procurement, Ex-Vivo Lung Perfusion (EVLP) is performed. From November 2014 ten subjects were considered potential donors; one of these underwent the full process of procurement, EVLP, and transplantation. The donor was a 46-year-old male who died because of thoracic aortic dissection. Lungs were procured 4 hours and 48 minutes after death, and deemed suitable for transplantation after EVLP. Lungs were then offered to a rapidly deteriorating recipient with cystic fibrosis (LAS 46) who consented to the transplant in this experimental setting. Six months after transplantation, the recipient is in good condition (FEV1 85%) with no signs of rejection. This protocol allowed procurement of lungs from an uncontrolled donor after circulatory determination of death following an extended period of warm ischemia