לוח שנה משולב

RNA abundance and DNA copy number are routinely measured in high-throughput
using microarray and next generation sequencing (NGS) technologies, and the
attributes of different platforms have been extensively analyzed. Recently, the application of both microarrays and NGS has expanded to include microRNAs (miRNAs), but the relative performance of these methods has not been rigorously characterized.
We analyzed three biological samples across six miRNA microarray platforms
and compared their hybridization performance. We examined the utility of these platforms, as well as NGS, for the detection of differentially expressed miRNAs.
The results were validated for 89 miRNAs by real-time RT-PCR and the use of this assay as a “gold standard” is challenged. Lastly, we implement a novel method to evaluate false-positive and false-negative rates for all methods in the absence of a reference method.

Single layer graphene is of great interest for electronic applications as an atomically thin, zero band gap semiconductor. Experimental results so far have been limited due to the difficulty of creating large, single layer samples. Here we report a competitive approach to the large-scale production of single layer chemically converted graphene (CCG). By dispersing graphite oxide paper in pure hydrazine, we are able to remove oxygen functionalities while preserving the integrity and restoring the planar geometry of single sheets. The CCG sheets produced with this method have among the largest areas of any yet reported (up to 20 x 40 m), making them relatively straightforward to process. Field effect devices have been fabricated by conventional photolithography and display currents that are three orders of magnitude higher than those previously reported for CCG. The versatility of solution processing also enables single layer graphene sheets to be registered using a PDMS stamping technique. Through surface energy manipulation, large-scale registration of graphene is now possible. Raman spectroscopy has been used to confirm uniform registration across large areas. Due to the large size of these sheets, comprehensive studies including optical microscopy, AFM, SEM and FET device characterization can all be performed on the same specimen. By combining graphene and carbon nanotubes, flexible, conducting, transparent windows can be made. This solution processing of carbon-based materials thus holds great promise for nanoelectronic applications.

Topological superconductors have been theoretically predicted as a new
class of time-reversal-invariant superconductors which are fully
gapped in the bulk but have protected gapless surface Andreev bound
states. We provide a simple criterion that directly identifies this
topological phase in extit{odd-parity} superconductors. We next
propose a two-orbital $U-V$ pairing model for the newly discovered
superconductor Cu_xBi_2Se_3. Due to its peculiar three-dimensional
Dirac band structure, we find that an inter-orbital triplet pairing
with odd-parity is favored in a significant part of the phase diagram,
and therefore gives rise to a topological superconductor phase.
Finally we propose sharp experimental tests of such a pairing
symmetry.

Neutron stars provide an observational probe of
Galactic chemical evolution, stellar evolution, physics
of ultra high magnetic fields, the equation of state of nuclear
matter, and General Relativity.
I will present three observational approaches to study
neutron stars. (i) Our ongoing efforts to obtain a spectrum of historical
Galactic supernovae using the Palomar transient factory,
and so to study the explosive birth of neutron stars observed today
within the supernova remnants; (ii) Searches for extragalactic soft gamma
ray repeaters (a form of highly magnetized, very young neutron stars) and
their implications to the energy reservoir of these objects; and (iii) A
new class of transients detected in radio wavebands that trace, most
likely, old "dead" neutron stars in our Galaxy which were mostly invisible
to date. This may provide a new (and the only) probe of the nature of this
illusive population.