Grain shape effects in bed load sediment transport.

Bed load sediment transport, in which wind or water flowing over a bed of sediment causes grains to roll or hop along the bed, is a critically important mechanism in contexts ranging from river restoration to planetary exploration. Despite its widespread occurrence, predictions of bed load sediment flux are notoriously imprecise. Many studies have focused on grain size variability as a source of uncertainty, but few have investigated the role of grain shape, even though shape has long been suspected to influence transport rates.

Palladium-catalyzed cross-coupling of H-phosphinate esters with chloroarenes.

The palladium-catalyzed cross-coupling reaction between H-phosphinate esters and chloroarenes or chloroheteroarenes is described. This reaction is the first general metal-catalyzed phosphorus-carbon bond-forming reaction between a phosphorus nucleophile and chloroarenes.

Strategies for the asymmetric synthesis of H-phosphinate esters.

Access to P-chiral H-phosphinates via desymmetrization of hypophosphite esters was investigated. The use of chiral auxiliaries, chiral catalysts, and of a bulky prochiral group that could lead to kinetic resolution was explored. A chiral NMR assay for enantiomeric excess determination of H-phosphinates was developed.

Congenital heart defects and fetal alcohol spectrum disorders.

Objective: Review of the prevalence of congenital heart defects (CHD) and fetal alcohol spectrum disorder (FASD).

Design: We conducted a search of the Medline and Pubmed databases to identify papers reporting the association. We then searched the reference lists of the papers and reference books for additional sources.

A staged screening strategy for prenatal alcohol exposure and maternal risk stratification.

Aims: To present an incremental process for a staged screening strategy to identify women at increased risk of having a child with fetal alcohol spectrum disorder (FASD) and to enhance the management of women using alcohol during pregnancy. We include an illustrative example of the development of a screening component using an existing data set.

Methods: We describe a seven-step protocol to screen for alcohol use during pregnancy.