Self-Injurious Behavior in Adolescents

Janis Whitlock discusses the epidemiology and and care of adolescents undertaking nonsuicidal self-injury, also called “deliberate self-harm.

Non-additive genome-wide association scan reveals a new gene associated with habitual coffee consumption

Coffee is one of the most consumed beverages world-wide and one of the primary sources of caffeine intake. Given its important health and economic impact, the underlying genetics of its consumption has been widely studied. Despite these efforts, much has still to be uncovered. In particular, the use of non-additive genetic models may uncover new information about the genetic variants driving coffee consumption. We have conducted a genome-wide association study in two Italian populations using additive, recessive and dominant models for analysis. This has uncovered a significant association in the PDSS2 gene under the recessive model that has been replicated in an independent cohort from the Netherlands (ERF). The identified gene has been shown to negatively regulate the expression of the caffeine metabolism genes and can thus be linked to coffee consumption. Further bioinformatics analysis of eQTL and histone marks from Roadmap data has evidenced a possible role of the identified SNPs in regulating PDSS2 gene expression through enhancers present in its intron. Our results highlight a novel gene which regulates coffee consumption by regulating the expression of the genes linked to caffeine metabolism. Further studies will be needed to clarify the biological mechanism which links PDSS2 and coffee consumption

A quantum dot single photon source driven by resonant electrical injection

We present a demonstration of single photon emission from an entirely electrically driven resonant injection quantum dot device. We selectively measure the emission from a single dot in the ensemble by tuning the applied bias so as to induce resonant tunneling into the dot. Direct injection of carriers into the dot leads to a suppression of background light, allowing us to demonstrate single photon emission from a single dot with no spectral filtering. We study the effects limiting the linewidths of photons emitted from the device. © 2013 AIP Publishing LLC