By decoding neural activity into useful behavioral commands, neural prosthetic systems seek to improve the lives of severely disabled human patients. Motor decoding algorithms, which map neural spiking data to control...
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By decoding neural activity into useful behavioral commands, neural prosthetic systems seek to improve the lives of severely disabled human patients. Motor decoding algorithms, which map neural spiking data to control parameters of a device such as a prosthetic arm, have received particular attention in the literature. Here, we highlight several outstanding problems that exist in most current approaches to decode algorithm design. These include two problems that we argue will unlikely result in further dramatic increases in performance, specifically spike sorting and spiking models. We also discuss three issues that have been less examined in the literature, and we argue that addressing these issues may result in dramatic future increases in performance. These include: non-stationarity of recorded waveforms, limitations of a linear mappings between neural activity and movement kinematics, and the low signal to noise ratio of the neural data. We demonstrate these problems with data from 39 experimental sessions with a non-human primate performing reaches and with recent literature. In all, this study suggests that research in cortically-controlled prosthetic systems may require reprioritization to achieve performance that is acceptable for a clinically viable human system.
DNA self-assembly is an emerging technique in DNA nanotechnology that holds promise for high impact applications such as in the synthesis of DNA-based nanodevices in medicine, robotics and electronics. Recent advancem...
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DNA self-assembly is an emerging technique in DNA nanotechnology that holds promise for high impact applications such as in the synthesis of DNA-based nanodevices in medicine, robotics and electronics. Recent advancements in technologies and ideas have spurred new growth in the area. The most significant challenge faced by designers in the field is the lack of algorithmic and software options to aid in the design process, and as a result the scope of synthesis has been restricted to modeling a limited set of shapes in 2D. In this paper, we propose a new design methodology called DNAjig to build DNA nanostructures. The highlights of this method are as follows: i) The construction procedure is based on a novel application of space-filling curves to model the shape of an arbitrary user-specified 2D or 3D object. ii) The method results in a simple, yet recursively constructable design layout that is inherently interlocked. iii) Almost all steps within the proposed design procedure can be automated and we present algorithms and a base-version implementation for the same. Wetlab validation showing the results of self-assembly of our first batch of computer generated 2D models is presented.
In this work, a focused ion beam (FIB) milling process has been developed to fabricate 50 nm Bi nanowire and transistor structures using FEI-200 dual beam FIB system. For the fabrication, 50 nm bismuth film was therma...
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In this work, a focused ion beam (FIB) milling process has been developed to fabricate 50 nm Bi nanowire and transistor structures using FEI-200 dual beam FIB system. For the fabrication, 50 nm bismuth film was thermally evaporated through EBL patterned PMMA windows onto SiO2 substrates with pre-defined contact pads. Bi nanowire widths ranging from 30 nm to 100 nm have been successfully fabricated by milling out unwanted areas using 30 KeV Ga+ ion beam. A single-pixel-line ion beam blanking technique has been utilised to fabricate Bi nanowire as small as 30 nm in diameter and few micrometers long. In order to form good ohmic contacts for sub 50 nm bismuth nanowires, a drill-and-fill process has been developed using FIB to sputter away the surface oxide of bismuth after the in-situ platinum nanowire contacts deposition. To our knowledge, this is the first time a focused ion beam process has been used to fabricate bismuth nanowire. The fabricated Bi nanowires were electrically characterised using a semiconductor analyser that showed good ohmic contact to the electrodes. In this paper, the fabrication experiments and the characterisation results for Bi nanowires as small as 50 nm in diameter are presented. Several FIB issues involved in Bi device making and ohmic contacts to Bi nanowires will also be discussed. [ABSTRACT FROM AUTHOR]
Dynamic imaging with MRI holds great promise for visualizing soft tissue structures in the oropharyngeal region during speech and swallowing studies. However, MRI suffers from historically slow acquisition speed and s...
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Dynamic imaging with MRI holds great promise for visualizing soft tissue structures in the oropharyngeal region during speech and swallowing studies. However, MRI suffers from historically slow acquisition speed and sensitivity to significant magnetic susceptibility differences in this region. In this work, we describe our efforts in creating high temporal resolution, serial acquisitions of the muscles of the oropharyngeal region. We describe our imaging approach that leads to acquisition rates of up to 21 frames per second. Additionally, we compare the serial acquisition scheme to gated acquisitions that suffer from temporal blur due to limited repeatability of the dynamic action.
Gerry, Ma, and Vrscay [Phys. Rev. A 39, 668 (1989)] studied the time evolution of SU(1,1) coherent states for the damped harmonic oscillator by introducing the Kanai-Caldirola Hamiltonian. The purposes of this Brief R...
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Gerry, Ma, and Vrscay [Phys. Rev. A 39, 668 (1989)] studied the time evolution of SU(1,1) coherent states for the damped harmonic oscillator by introducing the Kanai-Caldirola Hamiltonian. The purposes of this Brief Report are to demonstrate that there are somewhat serious errors on their results and to correct them. Most of the figures given in their work are reproduced with correction in order to facilitate our explanation of results.
We report on the fabrication of a macroporous silicon diode that successfully operates in a photovoltaic mode of energy conversion. Typical device structures are fabricated on 4″, Cz grown, , p-type, 5 – 30 Ω-cm, S...
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The history of power compression is a series of developmental epochs that are (1) characteristically marked by a technological breakthrough and (2) generally separated by a factor of ~10[10] in power density. Based on...
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The history of power compression is a series of developmental epochs that are (1) characteristically marked by a technological breakthrough and (2) generally separated by a factor of ~10[10] in power density. Based on new advances in high-power coherent x-ray technology, the transition to a new nuclear epoch of laser interactions is presently commencing. Chief outcomes foreseen are (1) the generation of power densities in the 10[28]-10[30] W/cm[3] realm, (2) the controlled induction of nuclear interactions, and (3) the production of new states and forms of nuclear matter. [ABSTRACT FROM AUTHOR]
The focus of this paper is to describe studies on pre-prepared hydrophobic CdSeS(ZnS) quantum dots (QDs) at the air-water interface. Surface pressure-area (π-A) isotherms were extensively studied using QDs capped wit...
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