The development of cryogenic storage systems for space flight

Development of cryogenic storage systems for manned space fligh

Internal Conversion of Valence-Shell Electrons : Measurement and Analysis for the 10.84 KeV Transition in 206Bi

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Neonatal Intensive Care Unit Resource Use for Infants at 22 Weeks\u27 Gestation in the US, 2008-2021

IMPORTANCE: During the past decade, clinical guidance about the provision of intensive care for infants born at 22 weeks\u27 gestation has changed. The impact of these changes on neonatal intensive care unit (NICU) resource utilization is unknown. OBJECTIVE: To characterize recent trends in NICU resource utilization for infants born at 22 weeks\u27 gestation compared with other extremely preterm infants (≤28 weeks\u27 gestation) and other NICU-admitted infants. DESIGN, SETTING, AND PARTICIPANTS: This is a serial cross-sectional study of 137 continuously participating NICUs in 29 US states from January 1, 2008, through December 31, 2021. Participants included infants admitted to the NICU. Data analysis was performed from October 2022 to August 2023. EXPOSURES: Year and gestational age at birth. MAIN OUTCOMES AND MEASURES: Measures of resource utilization included NICU admissions, NICU bed-days, and ventilator-days. RESULTS: Of 825 112 infants admitted from 2008 to 2021, 60 944 were extremely preterm and 872 (466 [53.4%] male; 18 [2.1%] Asian; 318 [36.5%] Black non-Hispanic; 218 [25.0%] Hispanic; 232 [26.6%] White non-Hispanic; 86 [9.8%] other or unknown) were born at 22 weeks\u27 gestation. NICU admissions at 22 weeks\u27 gestation increased by 388%, from 5.7 per 1000 extremely preterm admissions in 2008 to 2009 to 27.8 per 1000 extremely preterm admissions in 2020 to 2021. The number of NICU admissions remained stable before the publication of updated clinical guidance in 2014 to 2016 and substantially increased thereafter. During the study period, bed-days for infants born at 22 weeks increased by 732%, from 2.5 per 1000 to 20.8 per 1000 extremely preterm NICU bed-days; ventilator-days increased by 946%, from 5.0 per 1000 to 52.3 per 1000 extremely preterm ventilator-days. The proportion of NICUs admitting infants born at 22 weeks increased from 22.6% to 45.3%. Increases in NICU resource utilization during the period were also observed for infants born at less than 22 and at 23 weeks but not for other gestational ages. In 2020 to 2021, infants born at less than or equal to 23 weeks\u27 gestation comprised 1 in 117 NICU admissions, 1 in 34 of all NICU bed-days, and 1 in 6 of all ventilator-days. CONCLUSIONS AND RELEVANCE: In this serial cross-sectional study of 137 US NICUs from 2008 to 2021, an increasing share of resources in US NICUs was allocated to infants born at 22 weeks\u27 gestation, corresponding with changes in national clinical guidance

Heterogeneity of Treatment Effects of Hydrocortisone by Risk of Bronchopulmonary Dysplasia or Death Among Extremely Preterm Infants in the National Institute of Child Health and Human Development Neonatal Research Network Trial: A Secondary Analysis of a Randomized Clinical Trial.

IMPORTANCE: Extremely preterm infants who develop bronchopulmonary dysplasia (BPD) are at a higher risk for adverse pulmonary and neurodevelopmental outcomes. In the National Institute of Child Health and Human Development Neonatal Research Network (NICHD NRN) Hydrocortisone Trial, hydrocortisone neither reduced rates of BPD or death nor increased rates of neurodevelopmental impairment (NDI) or death. OBJECTIVE: To determine whether estimated risk for grades 2 to 3 BPD or death is associated with the effect of hydrocortisone on the composite outcomes of (1) grades 2 to 3 BPD or death and (2) moderate or severe NDI or death. DESIGN, SETTING, AND PARTICIPANTS: This secondary post hoc analysis used data from the NICHD NRN Hydrocortisone Trial, which was a double-masked, placebo-controlled, randomized clinical trial conducted in 19 US academic centers. The NICHD HRN Hydrocortisone Trial enrolled infants born at a gestational age of less than 30 weeks who received mechanical ventilation for at least 7 days, including at the time of enrollment, and who were aged 14 to 28 postnatal days. Infants were enrolled between August 22, 2011, and February 4, 2018, with follow-up between 22 and 26 months of corrected age completed on March 29, 2020. Data were analyzed from September 13, 2021, to March 25, 2023. INTERVENTION: Infants were randomized to 10 days of hydrocortisone or placebo treatment. MAIN OUTCOMES AND MEASURES: Infants\u27 baseline risk of grades 2 to 3 BPD or death was estimated using the NICHD Neonatal BPD Outcome Estimator. Differences in absolute and relative treatment effects by baseline risk were evaluated using interaction terms in models fitted to the efficacy outcome of grades 2 to 3 BPD or death and the safety outcome of moderate or severe NDI or death by follow-up. RESULTS: Among the 799 infants included in the analysis (421 boys [52.7%]), the mean (SD) gestational age was 24.9 (1.5) weeks, and the mean (SD) birth weight was 715 (167) g. The mean estimated baseline risk for grades 2 to 3 BPD or death was 54% (range, 18%-84%) in the study population. The interaction between treatment group and baseline risk was not statistically significant on a relative or absolute scale for grades 2 to 3 BPD or death; the size of the effect ranged from a relative risk of 1.13 (95% CI, 0.82-1.55) in quartile 1 to 0.94 (95% CI, 0.81-1.09) in quartile 4. Similarly, the interaction between treatment group and baseline risk was not significant on a relative or absolute scale for moderate or severe NDI or death; the size of the effect ranged from a relative risk of 1.04 (95% CI, 0.80-1.36) in quartile 1 to 0.99 (95% CI, 0.80-1.22) in quartile 4. CONCLUSIONS AND RELEVANCE: In this secondary analysis of a randomized clinical trial, the effect of hydrocortisone vs placebo was not appreciably modified by baseline risk for grades 2 to 3 BPD or death

Effect of Reduced versus Usual Lipid Emulsion Dosing on Bilirubin Neurotoxicity and Neurodevelopmental Impairment in Extremely Preterm Infants: Study Protocol for a Randomized Controlled Trial

BACKGROUND: Bilirubin neurotoxicity (BN) occurs in premature infants at lower total serum bilirubin levels than term infants and causes neurodevelopmental impairment. Usual dose lipid infusions in preterm infants may increase free fatty acids sufficiently to cause bilirubin displacement from albumin, increasing passage of unbound bilirubin (UB) into the brain leading to BN and neurodevelopmental impairment not reliably identifiable in infancy. These risks may be influenced by whether cycled or continuous phototherapy is used to control bilirubin levels. OBJECTIVE: To assess differences in wave V latency measured by brainstem auditory evoked responses (BAER) at 34-36 weeks gestational age in infants born ≤ 750 g or \u3c 27 weeks\u27 gestational age randomized to receive usual or reduced dose lipid emulsion (half of the usual dose) irrespective of whether cycled or continuous phototherapy is administered. METHODS: Pilot factorial randomized controlled trial (RCT) of lipid dosing (usual and reduced) with treatment groups balanced between cycled or continuous phototherapy assignment. Eligible infants are born at ≤ 750 g or \u3c 27 weeks\u27 gestational age enrolled in the NICHD Neonatal Research Network RCT of cycled or continuous phototherapy. Infants will randomize 1:1 to reduced or usual dose lipid assignment during the first 2 weeks after birth and stratified by phototherapy assignment. Free fatty acids and UB will be measured daily using a novel probe. BAER testing will be performed at 34-36 weeks postmenstrual age or prior to discharge. Blinded neurodevelopmental assessments will be performed at 22-26 months. Intention-to-treat analyses will be performed with generalized linear mixed models with lipid dose and phototherapy assignments as random effects covariates, and assessment for interactions. Bayesian analyses will be performed as a secondary analysis. DISCUSSION: Pragmatic trials are needed to evaluate whether lipid emulsion dosing modifies the effect of phototherapy on BN. This factorial design presents a unique opportunity to evaluate both therapies and their interaction. This study aims to address basic controversial questions about the relationships between lipid administration, free fatty acids, UB, and BN. Findings suggesting a reduced lipid dose can diminish the risk of BN would support the need for a large multicenter RCT of reduced versus usual lipid dosing