26 research outputs found

    Resonant two-site tunnelling dynamics of bosons in a tilted optical superlattice

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    We study the non-equilibrium dynamics of a 1D Bose-Hubbard model in a gradient potential and a superlattice, beginning from a deep Mott insulator regime with an average filling of one particle per site. Studying a quench that is near resonance to tunnelling of the particles over two lattice sites, we show how a spin model emerges consisting of two coupled Ising chains that are coupled by interaction terms in a staggered geometry. We compare and contrast the behavior in this case with that in a previously studied case where the resonant tunnelling was over a single site. Using optimized tensor network techniques to calculate finite temperature behavior of the model, as well as finite size scaling for the ground state, we conclude that the universality class of the phase transition for the coupled chains is that of a tricritical Ising point. We also investigate the out-of-equilibrium dynamics after the quench in the vicinity of the resonance and compare dynamics with recent experiments realized without the superlattice geometry. This model is directly realizable in current experiments, and reflects a new general way to realize spin models with ultracold atoms in optical lattices.Comment: 12 pages, 6 figure

    Antenatal and postnatal corticosteroid and resuscitation induced lung injury in preterm sheep

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    <p>Abstract</p> <p>Background</p> <p>Initiation of ventilation using high tidal volumes in preterm lambs causes lung injury and inflammation. Antenatal corticosteroids mature the lungs of preterm infants and postnatal corticosteroids are used to treat bronchopulmonary dysplasia.</p> <p>Objective</p> <p>To test if antenatal or postnatal corticosteroids would decrease resuscitation induced lung injury.</p> <p>Methods</p> <p>129 d gestational age lambs (n = 5-8/gp; term = 150 d) were operatively delivered and ventilated after exposure to either 1) no medication, 2) antenatal maternal IM Betamethasone 0.5 mg/kg 24 h prior to delivery, 3) 0.5 mg/kg Dexamethasone IV at delivery or 4) Cortisol 2 mg/kg IV at delivery. Lambs then were ventilated with no PEEP and escalating tidal volumes (<it>V</it><sub>T</sub>) to 15 mL/kg for 15 min and then given surfactant. The lambs were ventilated with <it>V</it><sub>T </sub>8 mL/kg and PEEP 5 cmH<sub>2</sub>0 for 2 h 45 min.</p> <p>Results</p> <p>High V<sub>T </sub>ventilation caused a deterioration of lung physiology, lung inflammation and injury. Antenatal betamethasone improved ventilation, decreased inflammatory cytokine mRNA expression and alveolar protein leak, but did not prevent neutrophil influx. Postnatal dexamethasone decreased pro-inflammatory cytokine expression, but had no beneficial effect on ventilation, and postnatal cortisol had no effect. Ventilation increased liver serum amyloid mRNA expression, which was unaffected by corticosteroids.</p> <p>Conclusions</p> <p>Antenatal betamethasone decreased lung injury without decreasing lung inflammatory cells or systemic acute phase responses. Postnatal dexamethasone or cortisol, at the doses tested, did not have important effects on lung function or injury, suggesting that corticosteroids given at birth will not decrease resuscitation mediated injury.</p

    Systemic hydrocortisone to prevent bronchopulmonary dysplasia in preterm infants (the SToP-BPD study); a multicenter randomized placebo controlled trial

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    <p>Abstract</p> <p>Background</p> <p>Randomized controlled trials have shown that treatment of chronically ventilated preterm infants after the first week of life with dexamethasone reduces the incidence of the combined outcome death or bronchopulmonary dysplasia (BPD). However, there are concerns that dexamethasone may increase the risk of adverse neurodevelopmental outcome. Hydrocortisone has been suggested as an alternative therapy. So far no randomized controlled trial has investigated its efficacy when administered after the first week of life to ventilated preterm infants.</p> <p>Methods/Design</p> <p>The SToP-BPD trial is a randomized double blind placebo controlled multicenter study including 400 very low birth weight infants (gestational age < 30 weeks and/or birth weight < 1250 grams), who are ventilator dependent at a postnatal age of 7 - 14 days. Hydrocortisone (cumulative dose 72.5 mg/kg) or placebo is administered during a 22 day tapering schedule. Primary outcome measure is the combined outcome mortality or BPD at 36 weeks postmenstrual age. Secondary outcomes are short term effects on the pulmonary condition, adverse effects during hospitalization, and long-term neurodevelopmental sequelae assessed at 2 years corrected gestational age. Analysis will be on an intention to treat basis.</p> <p>Discussion</p> <p>This trial will determine the efficacy and safety of postnatal hydrocortisone administration at a moderately early postnatal onset compared to placebo for the reduction of the combined outcome mortality and BPD at 36 weeks postmenstrual age in ventilator dependent preterm infants.</p> <p>Trial registration number</p> <p>Netherlands Trial Register (NTR): <a href="http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=2768">NTR2768</a></p

    Changes in Survival and Neonatal Morbidity in Infants with a Birth Weight of 750 g or Less

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    Background: Improvement in perinatal and neonatal care has resulted in increased survival of extremely low birth weight (ELBW) infants. Objectives: To describe survival and neonatal morbidity in a cohort of ELBW infants, to compare two consecutive 5-year periods, and compare appropriate (AGA) with small for gestational age (SGA) infants (AGA >= p10, and SG

    Effect of Systemic Hydrocortisone Initiated 7 to 14 Days after Birth in Ventilated Preterm Infants on Mortality and Neurodevelopment at 2 Years' Corrected Age: Follow-up of a Randomized Clinical Trial

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    This follow-up to the STOP-BPD randomized clinical trial, which investigated the efficacy and safety of systemic hydrocortisone treatment initiated 7 to 14 days after birth in ventilator-dependent, very preterm infants in the Netherlands and Belgium at 36 weeks’ postmenstrual age, examines the prespecified composite of death and neurodevelopmental impairment among these infants at 2 years’ corrected age

    Development of Nationwide Recommendations to Support Prenatal Counseling in Extreme Prematurity

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    Contains fulltext : 204177.pdf (publisher's version ) (Closed access)OBJECTIVES: To develop a nationwide, evidence-based framework to support prenatal counseling in extreme prematurity, focusing on organization, decision-making, content, and style aspects. METHODS: A nationwide multicenter RAND-modified Delphi method study was performed between November 2016 and December 2017 in the Netherlands. Firstly, recommendations were extracted from literature and previous studies. Secondly, an expert panel (n = 21) with experienced parents, obstetricians, and neonatologists rated the recommendations on importance for inclusion in the framework. Thirdly, ratings were discussed in a consensus meeting. The final set of recommendations was approved and transformed into a framework. RESULTS: A total of 101 recommendations on organization, decision-making, content, and style were included in the framework, including tools to support personalization. The most important recommendations regarding organization were to have both parents involved in the counseling with both the neonatologist and obstetrician. The shared decision-making model was recommended for deciding between active support and comfort care. Main recommendations regarding content of conversation were explanation of treatment options, information on survival, risk of permanent consequences, impossibility to predict an individual course, possibility for multiple future decision moments, and a discussion on parental values and standards. It was considered important to avoid jargon, check understanding, and provide a summary. The expert panel, patient organization, and national professional associations (gynecology and pediatrics) approved the framework. CONCLUSIONS: A nationwide, evidence-based framework for prenatal counseling in extreme prematurity was developed. It contains recommendations and tools for personalization in the domains of organization, decision-making, content, and style of prenatal counseling

    Short-term pulmonary and systemic effects of hydrocortisone initiated 7-14 days after birth in ventilated very preterm infants: a secondary analysis of a randomised controlled trial

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    OBJECTIVE: Observational studies in preterm infants suggest that systemic hydrocortisone improves pulmonary condition but may also lead to systemic adverse effects. We report the short-term pulmonary and systemic effects of hydrocortisone initiated in the second week. DESIGN: Randomised placebo-controlled trial. SETTING: Dutch and Belgian neonatal intensive care units. PATIENTS: Infants born <30 weeks' gestation and/or birth weight <1250 g, and ventilator dependent in the second week of life. INTERVENTION: Infants were randomly assigned to a 22-day course of systemic hydrocortisone (cumulative dose 72.5 mg/kg; n=182) or placebo (n=190). MAIN OUTCOME MEASURES: Data on extubation, ventilator settings, glucose levels, and blood pressure were recorded daily and analysed during the first 7 days of treatment using linear mixed-effects models. RESULTS: Infants in the hydrocortisone group (24.3%) failed extubation less often compared with placebo (38.6%, crude risk difference: -14.3% (95% CI: -23.4% to -4.8%)). The estimated difference in daily rate of change between hydrocortisone and placebo was -0.42 cmH2O (95% CI: -0.48 to -0.36) for mean airway pressure, -0.02 (95% CI: -0.02 to -0.01) for fraction of inspired oxygen, -0.37 (95% CI: -0.44 to -0.30) for respiratory index, 0.14 mmol/L (95% CI: 0.08 to 0.21) for blood glucose levels and 0.83 mm Hg (95% CI: 0.58 to 1.09) for mean blood pressure. CONCLUSIONS: Systemic hydrocortisone initiated between 7 and 14 days after birth in ventilated preterm infants improves pulmonary condition, thereby facilitating weaning and extubation from invasive ventilation. The effects of hydrocortisone on blood glucose levels and blood pressure were mild and of limited clinical relevance. TRIAL REGISTRATION NUMBER: Netherlands Trial Register (NTR2768; https://www.trialregister.nl/trial/2640) and European Union Clinical Trials Register (EudraCT, 2010-023777-19)

    Effect of systemic hydrocortisone in ventilated preterm infants on parent-reported behavioural outcomes at 2 years' corrected age : follow-up of a randomised clinical trial

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    ObjectiveTo report the parent-reported behavioural outcomes of infants included in the Systemic Hydrocortisone To Prevent Bronchopulmonary Dysplasia in preterm infants study at 2 years' corrected age (CA). DesignRandomised placebo-controlled trial. SettingDutch and Belgian neonatal intensive care units. PatientsInfants born 55) were found in 22.9%, 19.1% and 29.4% of infants for total, internalising and externalising problems, respectively; these scores were not significantly different between groups (mean difference -1.52 (95% CI -4.00 to 0.96), -2.40 (95% CI -4.99 to 0.20) and -0.81 (95% CI -3.40 to 1.77), respectively). In the subscales, we found a significantly lower T-score for anxiety problems in the hydrocortisone group (mean difference -1.26, 95% CI -2.41 to -0.12). ConclusionThis study found high rates of behaviour problems at 2 years' CA following very preterm birth, but these problems were not associated with hydrocortisone treatment initiated between 7 and 14 days after birth in ventilated preterm infants

    Short-term pulmonary and systemic effects of hydrocortisone initiated 7-14 days after birth in ventilated very preterm infants : a secondary analysis of a randomised controlled trial

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    Objective Observational studies in preterm infants suggest that systemic hydrocortisone improves pulmonary condition but may also lead to systemic adverse effects. We report the short-term pulmonary and systemic effects of hydrocortisone initiated in the second week. Design Randomised placebo-controlled trial. Setting Dutch and Belgian neonatal intensive care units. Patients Infants born <30 weeks' gestation and/or birth weight <1250 g, and ventilator dependent in the second week of life. Intervention Infants were randomly assigned to a 22-day course of systemic hydrocortisone (cumulative dose 72.5 mg/kg; n=182) or placebo (n=190). Main outcome measures Data on extubation, ventilator settings, glucose levels, and blood pressure were recorded daily and analysed during the first 7 days of treatment using linear mixed-effects models. Results Infants in the hydrocortisone group (24.3%) failed extubation less often compared with placebo (38.6%, crude risk difference: -14.3% (95% CI: -23.4% to -4.8%)). The estimated difference in daily rate of change between hydrocortisone and placebo was -0.42 cmH 2 O (95% CI: -0.48 to -0.36) for mean airway pressure, -0.02 (95% CI: -0.02 to -0.01) for fraction of inspired oxygen, -0.37 (95% CI: -0.44 to -0.30) for respiratory index, 0.14 mmol/L (95% CI: 0.08 to 0.21) for blood glucose levels and 0.83 mm Hg (95% CI: 0.58 to 1.09) for mean blood pressure. Conclusions Systemic hydrocortisone initiated between 7 and 14 days after birth in ventilated preterm infants improves pulmonary condition, thereby facilitating weaning and extubation from invasive ventilation. The effects of hydrocortisone on blood glucose levels and blood pressure were mild and of limited clinical relevance. Trial registration number Netherlands Trial Register (NTR2768; https://www.trialregister.nl/trial/2640) and European Union Clinical Trials Register (EudraCT, 2010-023777-19)
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