Objectives To assess the influence of clinical status on the association between total plasma bilirubin and unbound bilirubin on death or adverse neurodevelopmental outcomes at 18–22 months corrected age in extremely low birth weight infants. Method Total plasma biirubin and unbound biirubin were measured in 1,101 extremely low birth weight infants at 5±1 day of age. Clinical criteria were used to classify infants as clinically stable or unstable. Survivors were examined at 18–22 months corrected age by certified examiners. Outcome variables were death or neurodevelopmental impairment, death or cerebral palsy, death or hearing loss, and death prior to follow-up. For all outcomes, the interaction between bilirubin variables and clinical status was assessed in logistic regression analyses adjusted for multiple risk factors. Results Regardless of clinical status, an increasing level of unbound bilirubin was associated with higher rates of death or neurodevelopmental impairment, death or cerebral palsy, death or hearing loss and death before follow-up. Total plasma bilirubin values were directly associated with death or neurodevelopmental impairment, death or cerebral palsy, death or hearing loss, and death before follow-up in unstable infants, but not in stable infants. An inverse association between total plasma bilirubin and death or cerebral palsy was found in stable infants. Conclusions In extremely low birth weight infants, clinical status at 5 days of age affects the association between total plasma and unbound bilirubin and death or adverse neurodevelopmental outcomes at 18–22 months of corrected age. An increasing level of UB is associated a higher risk of death or adverse neurodevelopmental outcomes regardless of clinical status. Increasing levels of total plasma bilirubin are directly associated with increasing risk of death or adverse neurodevelopmental outcomes in unstable, but not in stable infants.

Climate change plays a large role in driving species range shifts; however, the physical characteristics of an environment can also influence and alter species distributions. In New England salt marshes, the mud fiddler crab Minuca pugnax is expanding its range north of Cape Cod, MA, into the Gulf of Maine (GoM) due to warming waters. The burrowing lifestyle of M. pugnax means sediment compaction in salt marshes may influence the ability of crabs to dig, with more compact soils being resistant to burrowing. Previous studies indicate that salt marshes along the GoM have a higher sediment compaction relative to marshes south of Cape Cod. Physical characteristics of this habitat may be influencing the burrowing performance of M. pugnax and therefore the continuation of their northward range expansion into the GoM. We conducted a controlled laboratory experiment to determine if compaction affects the burrowing activity of M. pugnax in historical and range-expanded populations. We manipulated sediment compaction in standardized lab assays and measured crab burrowing performance with individuals collected from Nantucket (NAN, i.e. historical range) and the Plum Island Estuary (PIE, i.e. expanded range). We determined compaction negatively affected burrowing ability in crabs from both sites; however, crabs from PIE have a higher probability of burrowing in higher sediment compactions than NAN crabs. In addition, PIE crabs were more likely to burrow overall. We conclude that site level differences in compaction are likely altering burrowing behavior in the crab’s expanded-range territory by way of local adaptation or phenotypic plasticity.

Rate constants for the dehydrochlorination of the title compounds by anionic bases in alcoholic solvents are those for simple proton transfer. Rate and estimated equilibrium data for these reactions can be approximately analysed in terms of the Marcus theory of proton transfer. In one reaction series comprising the reactions of para-substituted Ar2CHCC13 compounds with NaOMe in MeOH, the work term (wr) and the intrinsic free energy of activation (ΔG?) are comparable and large. The change in kH/kD with variation in substituent can be quantitatively rationalized, and the fact that kH/kD does not pass through a maximum even though ΔpK = 0 within the series can be understood. Although the required rate-equilibrium parabolic relationship for a second series involving the reactions of (p-ClC6H4)2CHCCl3 with a series of bases is obtained, anomalous Marcus parameters are derived, and reasons for the anomalies are given. A revised set of approximate pKa values for Ar2CHCCl3 compounds is presented, and more precise experimental values of rate constants for the reactions of (p-NO2C6H4)2CHCC13 and (p-NO2C6H4)2CDCCl3 with NaOMe in MeOH are provided.

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