874 research outputs found
Resuscitation of term and near-term newborns in low-resourced settings : Studies of positive end-expiratory pressure and expired CO2 during bag-mask ventilation at birth
No full textBackground: An estimated 0.7 million newborns die due to perinatal asphyxia each year, most are born at or near term. The major burden of preventable newborn deaths occur in low-resourced settings. A self-inflating bag is the most used and available equipment to save newborn lives globally. To aerate the lungs is key to survival. Expired CO2 (ECO2) may be an indicator for lung aeration, and positive end-expiratory pressure (PEEP) may facilitate aeration of the lungs. Research aiming to improve ventilation in term and near-term newborns using a self-inflating bag is needed.
Aims: To investigate interpretation of ECO2 measured during bag-mask ventilation in the immediate newborn period, and assess whether this can be used as a marker for lung aeration, effective ventilation technique and prognosis. To study the effects of PEEP during bag-mask ventilation at or near term.
Methods: Two observational studies and one randomized clinical trial were performed at Haydom Lutheran Hospital in Tanzania. Data were collected using direct observation, side-stream CO2-monitoring, respiratory function monitoring and dry-electrode ECG. In the randomized trial, newborns in need of ventilation were assigned in blocks based on weeks to receive ventilations by self-inflating bag with or without a PEEP-valve.
Results: ECO2 during bag-mask ventilation at birth was significantly associated with both ventilation factors and clinical factors. Tidal volumes of 10-14 ml/kg and a low ventilation frequency of around 30 inflations/minute were associated with the fastest rise and highest levels of ECO2. ECO2 increased before heart rate, and measured levels of ECO2 during resuscitation could, similar to heart rate, predict 24-hours survival. Adding a PEEP-valve to the self-inflating bag did not improve heart rate, ECO2 or outcomes in term and near-term newborns despite delivery of an adequate PEEP.
Conclusions: ECO2 may be seen as a combined marker for lung aeration, airway patency and pulmonary circulation at birth. Tidal volumes of 10-14 ml/kg and ventilation frequencies of around 30 inflations/minute may be favorable to achieve a fast lung aeration. We found no clinical benefit of adding a PEEP-valve during bag-mask ventilation at birth in term and near-term newborns, and our study does not support routine use
PREPARED Present and past flow regime. On contourite drifts west of Spitsbergen
No full textThe Eurofleets-2 PREPARED cruise was conducted during June 5–15, 2014 on board the
Norwegian R/V G.O. Sars to investigate the present and past oceanographic flow regime and
patterns around two contourite drifts located in the eastern side of the Fram Strait (south-western
margin of Spitsbergen). To achieve the main objective of the project, we plan to use a full range
of time scaled measurements, from instantaneous (CTD) and seasonal (moorings) oceanographic
measurements, to the recent (Box corer) and geologic (Calypso core) past record.
Good weather and calm sea conditions allowed to fulfil the cruise program and to obtain a
high-quality and valuable dataset including: about 2780 km of underway measurements (hullmounted
ADCP and thermosalinograph); 60 CTD sites along 5 main transects; 22 sites for water
sampling at different depths for biogeochemical characterization of water masses; 13 mesozooplankton
samplings carried out by vertical hauls (WP2 net) and 20 by horizontal hauls
(Manta net) for the study of the present biological productivity of the area; about 120 km of site
survey including high-resolution multibeam map and sub-bottom profiles for the identification of
current-related structures; 5 Box cores; and 2 Calypso piston cores 19.67 and 17.37 m long with
an excellent sediment recovery up to 92%. In addition, 3 moorings were deployed for seasonal
measurements of water currents direction and velocity, water mass temperature and salinity and
to determine the annual amount of local sediment input.
Preliminary onboard analyses outlined the presence of a cold-oxygenated and low salinity
water mass moving in the deep northern part of the Storfjorden Trough under the effect of the
Corilis force and tide configuration considerably affecting the velocity and bottom distribution of
the cold water mass. The long Calypso cores contain the record of the past 20 ka with an
expanded Holocene sequence (over 5 m-thick) that will allow us to obtain very-high resolution
palaeoceanographic and palaeoenvironmental reconstructions in the area
The development of AZD7624 for prevention of exacerbations in COPD: a randomized controlled trial
No full textNaimish R Patel,1,2 Danen M Cunoosamy,1 Malin Fagerås,1 Ziad Taib,1 Sara Asimus,1 Tove Hegelund-Myrbäck,1 Sofia Lundin,1 Katerina Pardali,1 Nisha Kurian,1 Eva Ersdal,1 Cecilia Kristensson,1 Katarina Korsback,1 Robert Palmér,1 Mary N Brown,3 Steven Greenaway,4 Leonard Siew,4 Graham W Clarke,4,5 Stephen I Rennard,6,7 Barry J Make,8 Robert A Wise,9 Paul Jansson11Innovative Medicines and Early Development, AstraZeneca, Gothenburg, Sweden; 2Division of Pulmonary, Critical Care, and Sleep Medicine, Beth Israel Deaconess Hospital, Boston, MA, 3Innovative Medicines and Early Development, AstraZeneca, Boston, MA, USA; 4Quintiles Drug Research Unit at Guy’s Hospital, London, 5Department of Cardiothoracic Pharmacology, NHLI, Imperial College London, London, UK; 6Division of Pulmonary, Critical Care, Sleep and Allergy, University of Nebraska, Omaha, NE, USA; 7Clinical Discovery Unit, Innovative Medicines and Early Development, AstraZeneca, Cambridge, UK; 8Division of Pulmonary Sciences and Critical Care Medicine, National Jewish Health, University of Colorado, Denver, CO, 9Division of Pulmonary and Critical Care, School of Medicine, Johns Hopkins University, Baltimore, MD, USABackground: p38 mitogen-activated protein kinase (MAPK) plays a central role in the regulation and activation of pro-inflammatory mediators. COPD patients have increased levels of activated p38 MAPK, which correlate with increased lung function impairment, alveolar wall inflammation, and COPD exacerbations.Objectives: These studies aimed to assess the effect of p38 inhibition with AZD7624 in healthy volunteers and patients with COPD. The principal hypothesis was that decreasing lung inflammation via inhibition of p38α would reduce exacerbations and improve quality of life for COPD patients at high risk for acute exacerbations.Methods: The p38 isoform most relevant to lung inflammation was assessed using an in situ proximity ligation assay in severe COPD patients and donor controls. Volunteers aged 18–55 years were randomized into the lipopolysaccharide (LPS) challenge study, which investigated the effect of a single dose of AZD7624 vs placebo on inflammatory biomarkers. The Proof of Principle study randomized patients aged 40–85 years with a diagnosis of COPD for >1 year to AZD7624 or placebo to assess the effect of p38 inhibition in decreasing the rate of exacerbations.Results: The p38 isoform most relevant to lung inflammation was p38α, and AZD7624 specifically inhibited p38α and p38β isoforms in human alveolar macrophages. Thirty volunteers were randomized in the LPS challenge study. AZD7624 reduced the increase from baseline in sputum neutrophils and TNF-α by 56.6% and 85.4%, respectively (p<0.001). In the 213 patients randomized into the Proof of Principle study, there was no statistically significant difference between AZD7624 and placebo when comparing the number of days to the first moderate or severe exacerbation or early dropout.Conclusion: Although p38α is upregulated in the lungs of COPD patients, AZD7624, an isoform-specific inhaled p38 MAPK inhibitor, failed to show any benefit in patients with COPD. Keywords: COPD, inflammation, p38 mitogen-activated protein kinas
Production of pions, kaons, and protons as a function of the relative transverse activity classifier in pp collisions at √s = 13 TeV
No full textThe production of π ±, K±, and (p ̄) p is measured in pp collisions at s = 13 TeV in different topological regions of the events. Particle transverse momentum (p T) spectra are measured in the “toward”, “transverse”, and “away” angular regions defined with respect to the direction of the leading particle in the event. While the toward and away regions contain the fragmentation products of the near-side and away-side jets, respectively, the transverse region is dominated by particles from the Underlying Event (UE). The relative transverse activity classifier, R T = N T/〈N T〉, is used to group events according to their UE activity, where N T is the measured charged-particle multiplicity per event in the transverse region and 〈N T〉 is the mean value over all the analysed events. The first measurements of identified particle p T spectra as a function of R T in the three topological regions are reported. It is found that the yield of high transverse momentum particles relative to the R T-integrated measurement decreases with increasing R T in both the toward and the away regions, indicating that the softer UE dominates particle production as R T increases and validating that R T can be used to control the magnitude of the UE. Conversely, the spectral shapes in the transverse region harden significantly with increasing R T. This hardening follows a mass ordering, being more significant for heavier particles. Finally, it is observed that the p T-differential particle ratios (p+p ̄)/(π++π−) and (K+ + K−)/(π + + π −) in the low UE limit (R T → 0) approach expectations from Monte Carlo generators such as PYTHIA 8 with Monash 2013 tune and EPOS LHC, where the jet-fragmentation models have been tuned to reproduce e+e− results. [Figure not available: see fulltext.
Measurements of inclusive jet spectra in pp and central Pb-Pb collisions at root S-NN=5.02 TeV
No full textThis article reports measurements of the p(T)-differential inclusive jet cross section in pp collisions at root S = 5.02 TeV and the p(T)-differential inclusive jet yield in Pb-Pb 0-10% central collisions at root S-NN = 5.02 TeV. Jets were reconstructed at midrapidity with the ALICE tracking detectors and electromagnetic calorimeter using the anti-k(T) algorithm. For pp collisions, we report jet cross sections for jet resolution parameters R = 0.1-0.6 over the range 20 < p(T,jet) < 140 GeV/c, as well as the jet cross-section ratios of different R and comparisons to two next-to-leading-order (NLO)-based theoretical predictions. For Pb-Pb collisions, we report the R = 0.2 and R = 0.4 jet spectra for 40 < p(T,jet) < 140 GeV/c and 60 < p(T,jet) < 140 GeV/c, respectively. The scaled ratio of jet yields observed in Pb-Pb to pp collisions, R-AA, is constructed, and exhibits strong jet quenching and a clear p(T) dependence for R = 0.2. No significant R dependence of the jet R-AA is observed within the uncertainties of the measurement. These results are compared to several theoretical predictions
Present and past flow regime on contourite drifts west of Spitsbergen: preliminary results from Eurofleet 2 PREPARED cruise (June 2014).
No full textEurofleets-2 PREPARED cruise was conducted during June 5–15, 2014 on board the Norwegian R/V G.O. Sars to investigate the present and past oceanographic flow regime and patterns around two contourite drifts located in the eastern side of the Fram Strait (south-western margin of Spitsbergen). To achieve the main objective of the project, a full range of time scaled measurements was planned, from instantaneous (CTD) and seasonal (moorings) oceanographic measurements, to the recent (Box corer) and geologic (Calypso core) past record. The successful cruise recovered about 2780 km of underway measurements (hull-mounted ADCP and thermosalinograph); 60 CTD sites along 5 main transects; 22 sites for water sampling at different depths for biogeochemical characterization of water masses; 13 meso-zooplankton samplings carried out by vertical hauls (WP2 net) and 20 by horizontal hauls (Manta net) for the study of the present biological productivity of the area; about 120 km of site survey including high-resolution multibeam map and sub-bottom profiles for the identification of current related structures; 5 Box cores; and 2 Calypso piston cores 19.67 and 17.37 m long with an excellent sediment recovery up to 92%. In addition, 3 moorings were deployed for seasonal measurements of water currents direction and velocity, water mass temperature and salinity and to determine the annual amount of local sediment input. Preliminary onboard analyses outlined the presence of a cold-oxygenated and low salinity water mass moving in the deep northern part of the Storfjorden Trough under the effect of the Corilis force and tide configuration considerably affecting the velocity and bottom distribution of the cold water mass. The long Calypso cores contain the record of the past 20 ka with an exceptionally expanded Holocene sequence (over 5 m-thick) that will allow us to obtain very-high resolution palaeoceanographic and palaeoenvironmental reconstructions in the area
Measurement of inclusive and leading subjet fragmentation in pp and Pb–Pb collisions at √sNN = 5.02 TeV
No full textThis article presents new measurements of the fragmentation properties of jets in both proton–proton (pp) and heavy-ion collisions with the ALICE experiment at the Large Hadron Collider (LHC). We report distributions of the fraction zr of transverse momentum carried by subjets of radius r within jets of radius R. Charged-particle jets are reconstructed at midrapidity using the anti-k T algorithm with jet radius R = 0.4, and subjets are reconstructed by reclustering the jet constituents using the anti-k T algorithm with radii r = 0.1 and r = 0.2. In proton–proton collisions, we measure both the inclusive and leading subjet distributions. We compare these measurements to perturbative calculations at next-to-leading logarithmic accuracy, which suggest a large impact of threshold resummation and hadronization effects on the zr distribution. In heavy-ion collisions, we measure the leading subjet distributions, which allow access to a region of harder jet frag- mentation than has been probed by previous measurements of jet quenching via hadron fragmentation distributions. The zr distributions enable extraction of the parton-to-subjet fragmentation function and allow for tests of the universality of jet fragmentation functions in the quark–gluon plasma (QGP). We find no significant modification of zr distributions in Pb–Pb compared to pp collisions. However, the distributions are also consistent with a hardening trend for zr < 0.95, as predicted by several jet quenching models. As zr → 1 our results indicate that any such hardening effects cease, exposing qualitatively new possibilities to disentangle competing jet quenching mechanisms. By comparing our results to theoretical calculations based on an independent extraction of the parton-to-jet fragmentation function, we find consistency with the universality of jet fragmentation and no indication of factorization breaking in the QGP. [Figure not available: see fulltext.]
Measurement of the radius dependence of charged-particle jet suppression in Pb-Pb collisions at √SNN=5.02 TeV
No full textThe ALICE Collaboration reports a differential measurement of inclusive jet suppression using pp and Pb–Pb collision data at a center-of-mass energy per nucleon–nucleon collision sNN=5.02 TeV. Charged-particle jets are reconstructed using the anti-kT algorithm with resolution parameters R=0.2, 0.3, 0.4, 0.5, and 0.6 in pp collisions and R=0.2, 0.4, 0.6 in central (0–10%), semi-central (30–50%), and peripheral (60–80%) Pb–Pb collisions. A novel approach based on machine learning is employed to mitigate the influence of jet background. This enables measurements of inclusive jet suppression in new regions of phase space, including down to the lowest jet pT≥40 GeV/c at R=0.6 in central Pb–Pb collisions. This is an important step for discriminating different models of jet quenching in the quark–gluon plasma. The transverse momentum spectra, nuclear modification factors, derived cross section, and nuclear modification factor ratios for different jet resolution parameters of charged-particle jets are presented and compared to model predictions. A mild dependence of the nuclear modification factor ratios on collision centrality and resolution parameter is observed. The results are compared to a variety of jet-quenching models with varying levels of agreement
Multiplicity dependence of charged-particle jet production in pp collisions at
No full textThe multiplicity dependence of jet production in pp collisions at the centre-of-mass energy of is studied for the first time. Jets are reconstructed from charged particles using the anti- algorithm with resolution parameters R varying from 0.2 to 0.7. The jets are measured in the pseudorapidity range and in the transverse momentum range . The multiplicity intervals are categorised by the ALICE forward detector V0. The differential cross section of charged-particle jets are compared to leading order (LO) and next-to-leading order (NLO) perturbative quantum chromodynamics (pQCD) calculations. It is found that the data are better described by the NLO calculation, although the NLO prediction overestimates the jet cross section below . The cross section ratios for different R are also measured and compared to model calculations. These measurements provide insights into the angular dependence of jet fragmentation. The jet yield increases with increasing self-normalised charged-particle multiplicity. This increase shows only a weak dependence on jet transverse momentum and resolution parameter at the highest multiplicity. While such behaviour is qualitatively described by the present version of PYTHIA, quantitative description may require implementing new mechanisms for multi-particle production in hadronic collisions
Measurement of inclusive and leading subjet fragmentation in pp and Pb–Pb collisions at s NN = 5.02 TeV
No full textAbstract This article presents new measurements of the fragmentation properties of jets in both proton–proton (pp) and heavy-ion collisions with the ALICE experiment at the Large Hadron Collider (LHC). We report distributions of the fraction z r of transverse momentum carried by subjets of radius r within jets of radius R. Charged-particle jets are reconstructed at midrapidity using the anti-k T algorithm with jet radius R = 0.4, and subjets are reconstructed by reclustering the jet constituents using the anti-k T algorithm with radii r = 0.1 and r = 0.2. In proton–proton collisions, we measure both the inclusive and leading subjet distributions. We compare these measurements to perturbative calculations at next-to-leading logarithmic accuracy, which suggest a large impact of threshold resummation and hadronization effects on the z r distribution. In heavy-ion collisions, we measure the leading subjet distributions, which allow access to a region of harder jet frag- mentation than has been probed by previous measurements of jet quenching via hadron fragmentation distributions. The z r distributions enable extraction of the parton-to-subjet fragmentation function and allow for tests of the universality of jet fragmentation functions in the quark–gluon plasma (QGP). We find no significant modification of z r distributions in Pb–Pb compared to pp collisions. However, the distributions are also consistent with a hardening trend for z r < 0.95, as predicted by several jet quenching models. As z r → 1 our results indicate that any such hardening effects cease, exposing qualitatively new possibilities to disentangle competing jet quenching mechanisms. By comparing our results to theoretical calculations based on an independent extraction of the parton-to-jet fragmentation function, we find consistency with the universality of jet fragmentation and no indication of factorization breaking in the QGP
- …
