ABSTRACT
The performance of six newly synthesized benzo[h]quinoline-derived acetonitrilo pentamethylcyclopentadienyl iridium(III) tetrakis(3,5-bis-trifluoromethylphenyl)borate salts bearing different substituents -X (-OMe, -H, -Cl, -Br, -NO2 and -(NO2 )2 ) on the heterochelating ligand were evaluated in the dehydro-O-silylation of benzyl alcohol and the monohydrosilylation of 4-methoxybenzonitrile by Et3 SiH, two reactions involving the electrophilic activation of the Si-H bond. The benchmark shows a direct dependence of the catalytic efficiency with the electronic effect of -X, which is confirmed by theoretical assessment of the intrinsic silylicities Π of hydridoiridium(III)-silylium adducts and by the theoretical evaluation of the propensity of hydridospecies to transfer the hydrido ligand to the activated substrate. The revisited analysis of the Ir-Si-H interactions shows that the most cohesive bond in hydridoiridium(III)-silylium adducts is the Ir-H one, while the Ir-Si is a weak donor-acceptor dative bond. The Si H interaction in all the cases is noncovalent in nature and dominated by electrostatics confirming the heterolytic cleavage of the hydrosilane's Si-H bond in this key catalytically relevant species.
ABSTRACT
Family-witnessed resuscitation is a controversial subject for healthcare professionals and support for the practice is not universal (Albarran and Stafford 1999, Kissoon 2006). Research suggests, however, that the advantages of this form of resuscitation for relatives far outweigh the disadvantages, and that hospital staff can support the practice without hindering the clinical care of patients. This article explores the ethical issues raised, as well as the views of patients, families and staff on the subject, and suggests that there should be guidelines on the practice in all emergency departments where it is likely to take place.
Subject(s)
Decision Making , Family , Resuscitation , Visitors to Patients , Humans , Practice Guidelines as Topic , Professional-Family Relations , United KingdomABSTRACT
Androgens delay fetal lung maturation through an androgen receptor (AR)-dependent mechanism. Type 2 and 5 17beta-hydroxysteroid dehydrogenases (17betaHSD) are involved in androgen inactivation and synthesis, respectively. We aimed to further characterize the human fetal lung potential for androgen metabolism and response. 17betaHSD2, 17betaHSD5, and AR mRNA levels were determined in lungs of mid-late gestation and in adult lungs, while protein detections were performed at mid-gestation. Relationships between levels of each mRNA and gestational age were observed. AR protein levels showed important differences among individuals of the same gestational window. 17betaHSD2 and AR were co-localized in epithelial and mesenchymal cells. AR was detected in both, cytoplasm and nucleus, which suggests fine-tuning of AR occupancy. In contrast, 17betaHSD5 was localized in a few epithelial cells of conducting zones. Our results support the existence of a local androgen metabolism in male and female human fetal lungs during the period of high-risk premature birth.
