Predicting the stability of atom-like and molecule-like unit-charge Coulomb three-particle systems

Non-relativistic quantum chemical calculations of the particle mass, m ± 2 , corresponding to the dissociation threshold in a range of Coulomb three-particle systems of the form {m ± 1 m ± 2 m ∓ 3 } , are performed variationally using a series solution method with a Laguerre-based wavefunction. These masses are used to calculate an accurate stability boundary, i.e., the line that separates the stability domain from the instability domains, in a reciprocal mass fraction ternary diagram. This result is compared to a lower bound to the stability domain derived from symmetric systems and reveals the importance of the asymmetric (mass-symmetry breaking) terms in the Hamiltonian at dissociation. A functional fit to the stability boundary data provides a simple analytical expression for calculating the minimum mass of a third particle required for stable binding to a two-particle system, i.e., for predicting the bound state stability of any unit-charge three-particle system

Neonatal mortality risk of vulnerable newborns : a descriptive analysis of subnational, population‐based birth cohorts for 238 143 live births in low‐ and middle‐income settings from 2000 to 2017

Objective: We aimed to understand the mortality risks of vulnerable newborns (defined as preterm and/or born weighing smaller or larger compared to a standard population), in low-and middle-income countries (LMICs). Design: Descriptive multi-country, secondary analysis of individual-level study data of babies born since 2000. Setting: Sixteen subnational, population-based studies from nine LMICs in sub-Saharan Africa, Southern and Eastern Asia, and Latin America. Population: Live birth neonates. Methods: We categorically defined five vulnerable newborn types based on size (large-or appropriate-or small-for-gestational age [LGA, AGA, SGA]), and term (T) and preterm (PT): T + LGA, T + SGA, PT + LGA, PT + AGA, and PT + SGA, with T + AGA (reference). A 10-type definition included low birthweight (LBW) and non-LBW, and a four-type definition collapsed AGA/LGA into one category. We performed imputation for missing birthweights in 13 of the studies. Main Outcome Measures: Median and interquartile ranges by study for the prevalence, mortality rates and relative mortality risks for the four, six and ten type classification. Results: There were 238 143 live births with known neonatal status. Four of the six types had higher mortality risk: T + SGA (median relative risk [RR] 2.8, interquartile range [IQR] 2.0–3.2), PT + LGA (median RR 7.3, IQR 2.3–10.4), PT + AGA (median RR 6.0, IQR 4.4–13.2) and PT + SGA (median RR 10.4, IQR 8.6–13.9). T + SGA, PT + LGA and PT + AGA babies who were LBW, had higher risk compared with non-LBW babies. Conclusions: Small and/or preterm babies in LIMCs have a considerably increased mortality risk compared with babies born at term and larger. This classification system may advance the understanding of the social determinants and biomedical risk factors along with improved treatment that is critical for newborn health

Complications Occurring Through 5 Years Following Primary Intraocular Lens Implantation for Pediatric Cataract

Importance Lensectomy with primary intraocular lens (IOL) implantation is often used in the management of nontraumatic pediatric cataract, but long-term data evaluating the association of age and IOL location with the incidence of complications are limited. Objective To describe the incidence of complications and additional eye surgeries through 5 years following pediatric lensectomy with primary IOL implantation and association with age at surgery and IOL location. Design, Setting, and Participants This prospective cohort study used Pediatric Eye Disease Investigator Group cataract registry data from 61 institution- and community-based practices over 3 years (June 2012 to July 2015). Participants were children younger than 13 years without baseline glaucoma who had primary IOL implantation (345 bilateral and 264 unilateral) for nontraumatic cataract. Data analysis was performed between September 2021 and January 2023. Exposures Lensectomy with primary IOL implantation. Main Outcome and Measures Five-year cumulative incidence of complications by age at surgery (<2 years, 2 to <4 years, 4 to <7 years, and 7 to <13 years) and by IOL location (sulcus vs capsular bag) were estimated using Cox proportional hazards models. Results The cohort included 609 eyes from 491 children (mean [SD] age, 5.6 [3.3] years; 261 [53%] male and 230 [47%] female). Following cataract extraction with primary IOL implantation, a frequent complication was surgery for visual axis opacification (VAO) (cumulative incidence, 32%; 95% CI, 27%-36%). Cumulative incidence was lower with anterior vitrectomy at the time of IOL placement (12%; 95% CI, 8%-16%) vs without (58%; 95% CI, 50%-65%), and the risk of undergoing surgery for VAO was associated with not performing anterior vitrectomy (hazard ratio [HR], 6.19; 95% CI, 3.70-10.34; P < .001). After adjusting for anterior vitrectomy at lens surgery, there were no differences in incidence of surgery for VAO by age at surgery (<2 years, HR, 1.35 [95% CI, 0.63-2.87], 2 to <4 years, HR, 0.86 [95% CI, 0.44-1.68], 4 to <7 years, HR, 1.06 [95% CI, 0.72-1.56]; P = .74) or by capsular bag vs sulcus IOL fixation (HR, 1.22; 95% CI, 0.36-4.17; P = .75). Cumulative incidence of glaucoma plus glaucoma suspect by 5 years was 7% (95% CI, 4%-9%), which did not differ by age after controlling for IOL location and laterality. Conclusions and Relevance In this cohort study, a frequent complication following pediatric lensectomy with primary IOL was surgery for VAO, which was associated with primary anterior vitrectomy not being performed but was not associated with age at surgery or IOL location. The risk of glaucoma development across all ages at surgery suggests a need for long-term monitoring

A global benchmark study using affinity-based biosensors

International audienceTo explore the variability in biosensor studies, 150 participants from 20 countries were given the same protein samples and asked to determine kinetic rate constants for the interaction. We chose a protein system that was amenable to analysis using different biosensor platforms as well as by users of different expertise levels. The two proteins (a 50-kDa Fab and a 60-kDa glutathione S-transferase [GST] antigen) form a relatively high-affinity complex, so participants needed to optimize several experimental parameters, including ligand immobilization and regeneration conditions as well as analyte concentrations and injection/dissociation times. Although most participants collected binding responses that could be fit to yield kinetic parameters, the quality of a few data sets could have been improved by optimizing the assay design. Once these outliers were removed, the average reported affinity across the remaining panel of participants was 620 pM with a standard deviation of 980 pM. These results demonstrate that when this biosensor assay was designed and executed appropriately, the reported rate constants were consistent, and independent of which protein was immobilized and which biosensor was used. (C) 2008 Elsevier Inc. All rights reserved