1,945 research outputs found
Experimental demonstration of tripartite entanglement and controlled dense coding for continuous variables
A tripartite entangled state of bright optical field is experimentally
produced using an Einstein-Podolsky-Rosen entangled state for continuous
variables and linear optics. The controlled dense coding among a sender, a
receiver and a controller is demonstrated by exploiting the tripartite
entanglement. The obtained three-mode position correlation and relative
momentum correlation between the sender and the receiver and thus the
improvements of the measured signal to noise ratios of amplitude and phase
signals with respect to the shot noise limit are 3.28dB and 3.18dB
respectively. If the mean photon number equals 11 the channel
capacity can be controllably inverted between 2.91 and 3.14. When is
larger than 1.0 and 10.52 the channel capacities of the controlled dense coding
exceed the ideal single channel capacities of coherent and squeezed state light
communication.Comment: 8 pages, 4 figure
Ionic effect on combing of single DNA molecules and observation of their force-induced melting by fluorescence microscopy
Molecular combing is a powerful and simple method for aligning DNA molecules
onto a surface. Using this technique combined with fluorescence microscopy, we
observed that the length of lambda-DNA molecules was extended to about 1.6
times their contour length (unextended length, 16.2 micrometers) by the combing
method on hydrophobic polymethylmetacrylate (PMMA) coated surfaces. The effects
of sodium and magnesium ions and pH of the DNA solution were investigated.
Interestingly, we observed force-induced melting of single DNA molecules.Comment: 12 page
Novel link between E2F1 and Smac/DIABLO: proapoptotic Smac/DIABLO is transcriptionally upregulated by E2F1
Deregulated expression of E2F1 not only promotes S-phase entry but also induces apoptosis. Although it has been well documented that E2F1 is able to induce p53-dependent apoptosis via raising ARF activity, the mechanism by which E2F induces p53-independent apoptosis remains unclear. Here we report that E2F1 can directly bind to and activate the promoter of Smac/DIABLO, a mitochondrial proapoptotic gene, through the E2F1-binding sites BS2 (−542 ∼ −535 bp) and BS3 (−200 ∼ −193 bp). BS2 and BS3 appear to be utilized in combination rather than singly by E2F1 in activation of Smac/DIABLO. Activation of BS2 and BS3 are E2F1-specific, since neither E2F2 nor E2F3 is able to activate BS2 or BS3. Using the H1299 ER-E2F1 cell line where E2F1 activity can be conditionally induced, E2F1 has been shown to upregulate the Smac/DIABLO expression at both mRNA and protein levels upon 4-hydroxytamoxifen treatment, resulting in an enhanced mitochondria-mediated apoptosis. Reversely, reducing the Smac/DIABLO expression by RNA interference significantly diminishes apoptosis induced by E2F1. These results may suggest a novel mechanism by which E2F1 promotes p53-independent apoptosis through directly regulating its downstream mitochondrial apoptosis-inducing factors, such as Smac/DIABLO
Development of 15kA/cm Fabrication Process for Superconducting Integrated Digital Circuits
A new fabrication process for superconducting integrated digital circuits is
reported. We have developed the "SIMIT Nb04" fabrication technique for
superconducting integrated circuits with Nb-based Josephson junctions based on
the validated "SIMIT Nb03" process and Chemical Mechanical Planarization (CMP)
technology. Seven Nb superconducting layers and one Mo resistor layer are
included in the "SIMIT Nb04" process with 19 mask levels. The device structure
is composed of active layers including junctions at the bottom, two passive
transmission line (PTL) layers in the middle and a DC power layer at the top.
The circuit fabrication started with the fabrication of Mo resistors with a
target sheet resistance Rsh of 3 , followed by the deposition of
Nb/Al-AlO/Nb trilayer Josephson-junction with a target critical current
density Jc at 15 kA/cm. To increase the Al-AlO barrier layer etching's
repeatability, an additional barrier protection layer was applied. To
accomplish high-quality planarization, we created a planarization procedure
coupled with dummy filling. To assess the process dependability and
controllability, a set of process control monitors (PCMs) for monitoring
fabrication and design parameters was designed and monitored. The successful
manufacturing and testing of a few small-scale circuits, like our standard
library cells, further attests to the viability of our fabrication process for
superconducting integrated circuits
- …