34 research outputs found
Vertical Field-Effect Transistor Based on Wavefunction Extension
We demonstrate a mechanism for a dual layer, vertical field-effect
transistor, in which nearly-depleting one layer will extend its wavefunction to
overlap the other layer and increase tunnel current. We characterize this
effect in a specially designed GaAs/AlGaAs device, observing a tunnel current
increase of two orders of magnitude at cryogenic temperatures, and we suggest
extrapolations of the design to other material systems such as graphene
Anastral spindle assembly and γ-tubulin in Drosophila oocytes
<p>Abstract</p> <p>Background</p> <p>Anastral spindles assemble by a mechanism that involves microtubule nucleation and growth from chromatin. It is still uncertain whether γ-tubulin, a microtubule nucleator essential for mitotic spindle assembly and maintenance, plays a role. Not only is the requirement for γ-tubulin to form anastral <it>Drosophila </it>oocyte meiosis I spindles controversial, but its presence in oocyte meiosis I spindles has not been demonstrated and is uncertain.</p> <p>Results</p> <p>We show, for the first time, using a bright GFP fusion protein and live imaging, that the <it>Drosophila </it>maternally-expressed γTub37C is present at low levels in oocyte meiosis I spindles. Despite this, we find that formation of bipolar meiosis I spindles does not require functional γTub37C, extending previous findings by others. Fluorescence photobleaching assays show rapid recovery of γTub37C in the meiosis I spindle, similar to the cytoplasm, indicating weak binding by γTub37C to spindles, and fits of a new, potentially more accurate model for fluorescence recovery yield kinetic parameters consistent with transient, diffusional binding.</p> <p>Conclusions</p> <p>The FRAP results, together with its mutant effects late in meiosis I, indicate that γTub37C may perform a role subsequent to metaphase I, rather than nucleating microtubules for meiosis I spindle formation. Weak binding to the meiosis I spindle could stabilize pre-existing microtubules or position γ-tubulin for function during meiosis II spindle assembly, which follows rapidly upon oocyte activation and completion of the meiosis I division.</p
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Picoinjection Enables Digital Detection of RNA with Droplet RT-PCR
The ability to add reagents to drops in a sequential fashion is necessary for numerous applications of microfluidics in biology. An important method for accomplishing this is picoinjection, a technique in which reagents are injected into aqueous drops usi
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Identification and genetic analysis of cancer cells with PCR-activated cell sorting
© The Author(s) 2014.Cell sorting is a central tool in life science research for analyzing cellular heterogeneity or enriching rare cells out of large populations. Although methods like FACS and FISH-FC can characterize and isolate cells from heterogeneou
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Design of a Scanning Gate Microscope for Mesoscopic Electron Systems in a Cryogen-Free Dilution Refrigerator
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