1,465 research outputs found
Charge transport and electron-hole asymmetry in low-mobility graphene/hexagonal boron nitride heterostructures
Graphene/hexagonal boron nitride (G/-BN) heterostructures offer an
excellent platform for developing nanoelectronic devices and for exploring
correlated states in graphene under modulation by a periodic superlattice
potential. Here, we report on transport measurements of nearly
-twisted G/-BN heterostructures. The heterostructures
investigated are prepared by dry transfer and thermally annealing processes and
are in the low mobility regime (approximately
at 1.9 K). The replica
Dirac spectra and Hofstadter butterfly spectra are observed on the hole
transport side, but not on the electron transport side, of the
heterostructures. We associate the observed electron-hole asymmetry to the
presences of a large difference between the opened gaps in the conduction and
valence bands and a strong enhancement in the interband contribution to the
conductivity on the electron transport side in the low-mobility G/-BN
heterostructures. We also show that the gaps opened at the central Dirac point
and the hole-branch secondary Dirac point are large, suggesting the presence of
strong graphene-substrate interaction and electron-electron interaction in our
G/-BN heterostructures. Our results provide additional helpful insight into
the transport mechanism in G/-BN heterostructures.Comment: 7 pages, 4 figure
Spatial clustering and common regulatory elements correlate with coordinated gene expression
Many cellular responses to surrounding cues require temporally concerted
transcriptional regulation of multiple genes. In prokaryotic cells, a
single-input-module motif with one transcription factor regulating multiple
target genes can generate coordinated gene expression. In eukaryotic cells,
transcriptional activity of a gene is affected by not only transcription
factors but also the epigenetic modifications and three-dimensional chromosome
structure of the gene. To examine how local gene environment and transcription
factor regulation are coupled, we performed a combined analysis of time-course
RNA-seq data of TGF-\b{eta} treated MCF10A cells and related epigenomic and
Hi-C data. Using Dynamic Regulatory Events Miner (DREM), we clustered
differentially expressed genes based on gene expression profiles and associated
transcription factors. Genes in each class have similar temporal gene
expression patterns and share common transcription factors. Next, we defined a
set of linear and radial distribution functions, as used in statistical
physics, to measure the distributions of genes within a class both spatially
and linearly along the genomic sequence. Remarkably, genes within the same
class despite sometimes being separated by tens of million bases (Mb) along
genomic sequence show a significantly higher tendency to be spatially close
despite sometimes being separated by tens of Mb along the genomic sequence than
those belonging to different classes do. Analyses extended to the process of
mouse nervous system development arrived at similar conclusions. Future studies
will be able to test whether this spatial organization of chromosomes
contributes to concerted gene expression.Comment: 30 pages, 9 figures, accepted in PLoS Computational Biolog
Generation of a High-Visibility Four-Photon Entangled State and Realization of a Four-Party Quantum Communication Complexity Scenario
We obtain a four-photon polarization-entangled state with a visibility as
high as (95.35\pm 0.45)% directly from a single down-conversion source. A
success probability of (81.54\pm 1.38)% is observed by applying this entangled
state to realize a four-party quantum communication complexity scenario (QCCS),
which comfortably surpass the classical limit of 50%. As a comparison, two
Einstein-Podolsky-Rosen (EPR) pairs are shown to implement the scenario with a
success probability of (73.89\pm 1.33)%. This four-photon state can be used to
fulfill decoherence-free quantum information processing and other advanced
quantum communication schemes.Comment: REVTEX 4.0, 4 pages, 4 figures, 1 tabl
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