Decoupling Graphene from SiC(0001) via Oxidation

When epitaxial graphene layers are formed on SiC(0001), the first carbon layer (known as the "buffer layer"), while relatively easy to synthesize, does not have the desirable electrical properties of graphene. The conductivity is poor due to a disruption of the graphene pi-bands by covalent bonding to the SiC substrate. Here we show that it is possible to restore the graphene pi-bands by inserting a thin oxide layer between the buffer layer and SiC substrate using a low temperature, CMOS-compatible process that does not damage the graphene layer

Meeting Report: The Use of Newborn Blood Spots in Environmental Research: Opportunities and Challenges

IntroductionDried blood spots (DBS) are routinely collected from newborns in the United States using a heel stick. The DBS are screened for inborn errors of metabolism and other disorders. More states are keeping residual spots and making them available for research purposes. DNA extraction from the DBS has been widely applied; however, the development of methods to measure a range of environmental toxicants in DBS has been a more recent goal for laboratory scientists and epidemiologists.ObjectivesThe purpose of the meeting was to examine the utility of DBS to measure environmental exposures. Speakers and discussants were invited to present data and discuss approaches to measure a range of analytes using DBS.ResultsThis meeting was held on 20 February 2007 at the University of North Carolina at Chapel Hill. The audience consisted of epidemiologists, chemists, and staff from state public health programs, the Centers for Disease Control and Prevention, and the National Institutes of Health. The meeting included presentations on measurement of flame-retarding chemicals and pesticides, metals, perchlorate, infectious agents, markers of immune status, and protein adducts. Analytical methods included mass spectrometry, atomic absorption, molecular methods, and microfluidic techniques. Significant progress was reported, but important challenges remain. Concerns including storage conditions, sample volume, contamination, and normalization require additional systematic evaluation. In addition, DBS storage and access policies require coordination.ConclusionsDBS remain a highly valuable resource for clinical, epidemiologic, and toxicologic investigation. The use of DBS to measure environmental exposures shows promise but additional work is necessary before more widespread use is warranted

Dynamic multifactor hubs interact transiently with sites of active transcription in Drosophila embryos.

The regulation of transcription requires the coordination of numerous activities on DNA, yet how transcription factors mediate these activities remains poorly understood. Here, we use lattice light-sheet microscopy to integrate single-molecule and high-speed 4D imaging in developing Drosophila embryos to study the nuclear organization and interactions of the key transcription factors Zelda and Bicoid. In contrast to previous studies suggesting stable, cooperative binding, we show that both factors interact with DNA with surprisingly high off-rates. We find that both factors form dynamic subnuclear hubs, and that Bicoid binding is enriched within Zelda hubs. Remarkably, these hubs are both short lived and interact only transiently with sites of active Bicoid-dependent transcription. Based on our observations, we hypothesize that, beyond simply forming bridges between DNA and the transcription machinery, transcription factors can organize other proteins into hubs that transiently drive multiple activities at their gene targets.Editorial noteThis article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (see decision letter)