13,801 research outputs found
DNA multi-bit non-volatile memory and bit-shifting operations using addressable electrode arrays and electric field-induced hybridization.
DNA has been employed to either store digital information or to perform parallel molecular computing. Relatively unexplored is the ability to combine DNA-based memory and logical operations in a single platform. Here, we show a DNA tri-level cell non-volatile memory system capable of parallel random-access writing of memory and bit shifting operations. A microchip with an array of individually addressable electrodes was employed to enable random access of the memory cells using electric fields. Three segments on a DNA template molecule were used to encode three data bits. Rapid writing of data bits was enabled by electric field-induced hybridization of fluorescently labeled complementary probes and the data bits were read by fluorescence imaging. We demonstrated the rapid parallel writing and reading of 8 (23) combinations of 3-bit memory data and bit shifting operations by electric field-induced strand displacement. Our system may find potential applications in DNA-based memory and computations
Rosetta Brains: A Strategy for Molecularly-Annotated Connectomics
We propose a neural connectomics strategy called Fluorescent In-Situ
Sequencing of Barcoded Individual Neuronal Connections (FISSEQ-BOINC),
leveraging fluorescent in situ nucleic acid sequencing in fixed tissue
(FISSEQ). FISSEQ-BOINC exhibits different properties from BOINC, which relies
on bulk nucleic acid sequencing. FISSEQ-BOINC could become a scalable approach
for mapping whole-mammalian-brain connectomes with rich molecular annotations
Piezoelectric Phononic Plates: Retrieving the Frequency Band Structure via All-electric Experiments
We propose an experimental technique based on all-electric measurements to
retrieve the frequency response of a one-dimensional piezoelectric phononic
crystal plate, structured periodically with millimeter-scaled metallic strips
on its two surfaces. The metallic electrodes, used for the excitation of
Lamb-like guided modes in the plate, ensure at the same time control of their
dispersion by means of externally loaded electric circuits that offer
non-destructive tunability in the frequency response of these structures. Our
results, in very good agreement with finite-element numerical predictions,
reveal interesting symmetry aspects that are employed to analyze the frequency
band structure of such crystals. More importantly, Lamb-like guided modes
interact with electric-resonant bands induced by inductance loads on the plate,
whose form and symmetry are discussed and analyzed in depth, showing
unprecedented dispersion characteristics.Comment: This is the version of the article before peer review or editing, as
submitted by an author to Smart Materials and Structures. IOP Publishing Ltd
is not responsible for any errors or omissions in this version of the
manuscript or any version derived from it. The Version of Record is available
online at https://doi.org/10.1088/1361-665X/ab4aa
Nanoantennas for visible and infrared radiation
Nanoantennas for visible and infrared radiation can strongly enhance the
interaction of light with nanoscale matter by their ability to efficiently link
propagating and spatially localized optical fields. This ability unlocks an
enormous potential for applications ranging from nanoscale optical microscopy
and spectroscopy over solar energy conversion, integrated optical
nanocircuitry, opto-electronics and density-ofstates engineering to
ultra-sensing as well as enhancement of optical nonlinearities. Here we review
the current understanding of optical antennas based on the background of both
well-developed radiowave antenna engineering and the emerging field of
plasmonics. In particular, we address the plasmonic behavior that emerges due
to the very high optical frequencies involved and the limitations in the choice
of antenna materials and geometrical parameters imposed by nanofabrication.
Finally, we give a brief account of the current status of the field and the
major established and emerging lines of investigation in this vivid area of
research.Comment: Review article with 76 pages, 21 figure
Ferromagnetic Semiconductors: Moving Beyond (Ga,Mn)As
The recent development of MBE techniques for growth of III-V ferromagnetic
semiconductors has created materials with exceptional promise in spintronics,
i.e. electronics that exploit carrier spin polarization. Among the most
carefully studied of these materials is (Ga,Mn)As, in which meticulous
optimization of growth techniques has led to reproducible materials properties
and ferromagnetic transition temperatures well above 150 K. We review progress
in the understanding of this particular material and efforts to address
ferromagnetic semiconductors as a class. We then discuss proposals for how
these materials might find applications in spintronics. Finally, we propose
criteria that can be used to judge the potential utility of newly discovered
ferromagnetic semiconductors, and we suggest guidelines that may be helpful in
shaping the search for the ideal material.Comment: 37 pages, 4 figure
Extremely short-length surface plasmon resonance sensors
The impact of the system design on the control of coupling between planar
waveguide modes and surface plasmon polaritons (SPP) is analyzed. We examine
how the efficiency of the coupling can be enhanced by an appropriate
dimensioning of a multi-layer device structure without using additional
gratings. We demonstrate that by proper design the length of the device can be
dramatically reduced through fabrication a surface plasmon resonance sensor
based on the SPP-photon transformation rather then on SPP dissipation
Andreev Level Qubit
We investigate the dynamics of a two-level Andreev bound state system in a
transmissive quantum point contact embedded in an rf-SQUID. Coherent coupling
of the Andreev levels to the circulating supercurrent allows manipulation and
read out of the level states. The two-level Hamiltonian for the Andreev levels
is derived, and the effect of interaction with the quantum fluctuations of the
induced flux is studied. We also consider an inductive coupling of qubits, and
discuss the relevant SQUID parameters for qubit operation and read out.Comment: 4 pages, 1 figur
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