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24th Annual Conference on Neural Information Processing Systems 2010, NIPS 2010

作者： Zhang, Yu Yeung, Dit-Yan Xu, Qian Department of Computer Science and Engineering Hong Kong University of Science and Technology Hong Kong Bioengineering Program Hong Kong University of Science and Technology Hong Kong

ISBN: (纸本)9781617823800

Recently, some variants of the l1 norm, particularly matrix norms such as the l1,2 and l 1,∞ norms, have been widely used in multi-task learning, compressed sensing and other related areas to enforce sparsity via joint regularization. In this paper, we unify the l 1,2 and l1,∞ norms by considering a family of l 1,q norms for 1 1,q norm. Based on this probabilistic interpretation, we develop a probabilistic model using the noninformative Jeffreys prior. We also extend the model to learn and exploit more general types of pairwise relationships between tasks. For both versions of the model, we devise expectation-maximization (EM) algorithms to learn all model parameters, including q, automatically. Experiments have been conducted on two cancer classification applications using microarray gene expression data.

关键词： Feature Selection

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HermesD: A high-rate long-range wireless transmission system for simultaneous multichannel neural recording applications

HermesD: A high-rate long-range wireless transmission system...

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作者： Miranda, Henrique Gilja, Vikash Chestek, Cindy A. Shenoy, Krishna V. Meng, Teresa H. Department of Electrical Engineering Stanford University Stanford CA 94305 United States Department of Computer Science Stanford University Stanford CA 94305 United States Departments of Electrical Engineering and Bioengineering Neurosciences Program Stanford University Stanford CA 94305 United States

HermesD is a high-rate, low-power wireless transmission system to aid research in neural prosthetic systems for motor disabilities and basic motor neuroscience. It is the third generation of our Hermes systems aimed at recording and transmitting neural activity from brain-implanted electrode arrays. This system supports the simultaneous transmission of 32 channels of broadband data sampled at 30 ks/s, 12 b/sample, using frequency-shift keying modulation on a carrier frequency adjustable from 3.7 to 4.1 GHz, with a link range extending over 20 m. The channel rate is 24 Mb/s and the bit stream includes synchronization and error detection mechanisms. The power consumption, approximately 142 mW, is low enough to allow the system to operate continuously for 33 h, using two 3.6-V/1200-mAh Li-SOCl2batteries. The transmitter was designed using off-the-shelf components and is assembled in a stack of three 28 mm × 28-mm boards that fit in a 38 mm × 38 mm × 51-mm aluminum enclosure, a significant size reduction over the initial version of HermesD. A 7-dBi circularly polarized patch antenna is used as the transmitter antenna, while on the receiver side, a 13-dBi circular horn antenna is employed. The advantages of using circularly polarized waves are analyzed and confirmed by indoor measurements. The receiver is a stand-alone device composed of several submodules and is interfaced to a computer for data acquisition and processing. It is based on the superheterodyne architecture and includes automatic frequency control that keeps it optimally tuned to the transmitter frequency. The HermesD communications performance is shown through bit-error rate measurements and eye-diagram plots. The sensitivity of the receiver is - 83 dBm for a bit-error probability of 10-9. Experimental recordings from a rhesus monkey conducting multiple tasks show a signal quality comparable to commercial acquisition systems, both in the low-frequency (local field potentials) and upper-frequency bands (act

关键词： Transmitters

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Correlation between primary motor cortex neural activity and fingertip force following transcranial magnetic stimulation

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Neural Regeneration Research 2010年第24期5卷 1905-1909页

作者： Xiaoying Wu Wensheng Hou Xiaolin Zheng Yingtao Jiang Jun Zheng Yan He Key Laboratory of Biorheological Science and Technology Ministry of Education Bioengineering College Chongqing University Chongqing 400044 China Department of Electrical and Computer Engineering University of Nevada Las Vegas NV 89154 USA Department of Computer Science New Mexico Institute of Mining and Technology Socorro NM 87801 USA

A better understanding of the neural mechanisms of finger-force regulation can help to explain the relationship between the central nervous system and nerve-muscle force, as well as assist in motor functional rehabilitation and the development robot hand designs. In the present study, 11 healthy volunteers performed a different target force-tracking task, which involved the index finger alone, index and middle finger together, and the combination of four fingers （i.e., index, middle, ring, and little）. The target force trace corresponded to 3 levels of 20% maximal voluntary changes （MVC）, 30% MVC, and 40% MVC in 20 seconds. In the test, an unexpected single 120% motor threshold transcranial magnetic stimulation was applied to the primary motor cortex （M1） during force tracking. Results revealed that peak force changes increased with increasing background force and the number of involved task fingers. These results demonstrate that M1 neural activities correlate with finger-force production, and M1 plays a role in finger-force control. Moreover, different neuronal networks were required for different finger patterns; a complicated task required multi-finger combinations and a complicated neuronal network comprised a large number of neurons.

关键词： transcranial magnetic stimulation finger motor control neural activities primary motor cortex background force

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Size-dependent infiltration and optical detection of nucleic acids in nanoscale pores

Size-dependent infiltration and optical detection of nucleic...

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作者： Lawrie, Jenifer L. Jiao, Yang Weiss, Sharon M. Department of Electrical Engineering and Computer Science Interdisciplinary Graduate Program in Materials Science Vanderbilt University Nashville TN 37235 United States

Experiments and complimentary simulations are presented to demonstrate the size-dependent infiltration and detection of variable length nucleic acids in porous silicon with controllable pore diameters in the range of 15-60 nm. The pore diameter must be tuned according to target molecule size in order to most effectively balance sensitivity and size-exclusion. A quantitative relationship between pore size (15-60 nm), nucleic acid length (up to ~5.3 nm), and sensor response is presented with smallermolecules detected more sensitively in smaller pores as long as the pore diameter is sufficient to enable molecular infiltration and binding in the pores. The density of probe molecules on the pore walls and subsequent hybridization efficiency for targetmolecule binding are also reported and are shown to depend strongly on the method of infiltration as well as the target molecule size.© 2010 IEEE.

关键词： Porous silicon

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Magnetic resonance imaging of irreversible electroporation in tubers

Magnetic resonance imaging of irreversible electroporation i...

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12th Mediterranean Conference on Medical and Biological engineering and Computing, MEDICON 2010

作者： Hjouj, Mohammad Rubinsky, Boris Center for Bioengineering School of Computer Science Engineering Hebrew University of Jerusalem Israel Department of Mechanical Engineering Graduate Program in Biophysics University of California Berkeley United States

ISBN: (纸本)9783642130380

Purpose: A preliminary study on the magnetic resonance (MRI) characteristics of (vegetable) tissue NTIRE is an emerging minimally invasive surgery technique for tissue ablation in which, microsecond, high electrical field pulses form permanent nano-scale defects in the cell membrane. Materials and Methods: The potato is used as the simplest conceivable first order tissue model for studying the MRI characteristics of electroporation, because while made of structured cells it does not have blood flow, it is relatively homogeneous and cell damage is readily visible through a natural oxidation process of the intracellular enzymes.. Clinical NTIRE sequences were applied to potato tubers and MRI sequences of the treated area were compared with colorimetric photographs. Results: A comparison of T1 weighted, T2 weighted, fluid attenuation inversion recovery (FLAIR) and short TI inversion recovery (STIR) of NTIRE shows that T1 weighted signals, such as FLAIR, produce brighter images of the treated areas. In contrast the images of the treated areas are completely lost with liquids enhancing and fat eliminating sequences, such as STIR. Conclusion: MRI can image tissue treated by NTIRE. A possible explanation for the findings is that by producing nanoscale defects in the cell membrane lipid bilayer, NTIRE causes an enhanced signal from the cell membrane lipids that in the treated cells are not bound anymore in a restrictive liquidgel membrane structure and have more degrees of freedom. © 2010 International Federation for Medical and Biological engineering.

关键词： Magnetic resonance imaging

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Comparison of forward and backward SHG images using Fourier transform-second-harmonic generation imaging

Comparison of forward and backward SHG images using Fourier ...

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Conference on Lasers and Electro-Optics, CLEO 2010

作者： Ramachandra Rao, Raghu Ambekar Mehta, Monal R. Leithem, Scott Toussaint, Kimani C. Jr. Department of Electrical and Computer Engineering Urbana-Champaign IL 61820 United States Department of Mechanical Science and Engineering Urbana-Champaign IL 61820 United States Affiliate in the departments of Electrical and Computer Engineering and Bioengineering University of Illinois Urbana-Champaign IL 61820 United States

We compare the forward and backward SHG images for porcine tendon, sclera, and ear cartilage using Fourier transform-second-harmonic generation microscopy. The preferred orientation and peaks in the magnitude spectrum... 详细信息

ISBN: (纸本)9781557528896

关键词： Harmonic generation

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Transcranial magnetic stimulation-induced finger force changes under various finger coordination patterns and target finger force phases

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Neural Regeneration Research 2010年第1期5卷 64-69页

作者： Xiaoying Wu Wensheng Hou Xiaolin Zheng Shan Shen Yingtao Jiang Jun Zheng Yan He Key Laboratory of Biorheological Science and Technology Ministry of Education Bioengineering College Chongqing University Chongqing 400044 China Psychology Department University of Surrey Guildford Surrey Gu2 7XFI UK Department of Computer Science New Mexico Institute of Mining and Technology Socorro NM 87801 USA Department of Electrical and Computer Engineering University of Nevada Las Vegas NV 89154 USA

BACKGROUND： The detection of motor evoked potential is utilized to explore neuromuscular finger coordination. The influence of transcranial magnetic stimulation on finger force has been investigated mainly on a single finger, and only time-dependent increased target finger force has been detected in the finger force task. OBJECTIVE： To explore the neural mechanism of finger force coordination in the motor cortex by observing the influence of various finger coordination patterns and patterns of transcranial magnetic stimulation （TMS）-induced finger force changes. DESIGN, TIME AND SETTING： Neurophysiological and behavioral study was performed at the Biomedical engineering Laboratory of Chongqing University from April to June 2008. PARTICIPANTS： A total of 10 healthy, university students, comprising 5 males and 5 females, aged 21-23 years, voluntarily participated in this study. All participants were right-handed, with normal or corrected vision. Individuals with upper limb complaints or other musculoskeletal disorders were excluded. METHODS： A target force-tracking task was conducted on the index finger, the index and middle fingers, and four fingers （index, middle, ring, and little）, respectively. Target force trace in a single trial consisted of a 6-second ramp phase, a 20-second constant phase, and a 6-second drop phase. During experimentation, an unpredictable single-pulse TMS （120% motor threshold） was applied to the primary motor cortex （M1） in each phase. MAIN OUTCOME MEASURES： Changes in peak force induced by TMS were obtained for each finger pattern during each force-tracking phase. Differences in force changes were tested between different finger pattems with regard to ramp, constant, and drop phases of target force. RESULTS： Under ramp, constant, and drop phases of target force, the increase in magnetic stimulation-induced finger forces changes positively correlated with the number of fingers involved in the force tracking task. The magnetic stimulation-ind

关键词： transcranial magnetic stimulation finger force peak force changes finger combination

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DYNAMIC OPTICAL COHERENCE ELASTOGRAPHY:A REVIEW

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Journal of Innovative Optical Health sciences 2010年第4期3卷 221-233页

作者： XING LIANG VASILICA CRECEA STEPHEN A.BOPPART Department of Electrical and Computer Engineering Beckman Institute for Advanced Science and Technology University of Illinois at Urbana-Champaign UrbanaIL61801USA Department of Physics Beckman Institute for Advanced Science and Technology University of Illinois at Urbana-Champaign UrbanaIL61801USA Departments of Electrical and Computer Engineering Bioengineering and Internal MedicineBeckman Institute for Advanced Science and Technology University of Illinois at Urbana-Champaign UrbanaIL61801USA Biophotonics Imaging Laboratory Beckman Institute for Advanced Science and Technology University of Illinois at Urbana-Champaign UrbanaIL61801USA

With the development of optical coherence tomography,the application optical coherence elastography(OCE)has gained more and more attention in biomechanics for its unique features including micron-scale resolution,real-time processing,and non-invasive *** this review,one group of OCE techniques,namely dynamic OCE,are introduced and discussed including external dynamic OCE mapping and imaging of ex vivo breast tumor,external dynamic OCE measurement of in vivo human skin,and internal dynamic OCE including acoustomotive OCE and magnetomotive *** techniques overcame some of the major drawbacks of traditional static OCE,and broadened the OCE application *** by scientific needs to engineer new quantitative methods that utilize the high micron-scale resolution achievable with optics,results of biomechanical properties were obtained from biological *** results suggest potential diagnostic and therapeutic clinical *** from these studies also help our understanding of the relationship between biomechanical variations and functional tissue changes in biological systems.

关键词： Optical coherence tomography optical coherence elastography biomechanics tissue characterization scattering phase measurements

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Distinguishing negatively-charged and highly conductive dislocations in gallium nitride using scanning Kelvin probe and conductive atomic force microscopy

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MRS Online Proceedings Library 2011年第1期743卷 L2.4.1-L2.4.6页

作者： Simpkins, Blake S. Yu, Edward T. Waltereit, Patrick Speck, James S. Department of Electrical and Computer Engineering and Program in Materials Science University of California at San Diego La Jolla USA Materials Department University of California Santa Barbara Santa Barbara USA

Scanning Kelvin probe microscopy (SKPM) and conductive atomic force microscopy (C-AFM) are used to image surfaces of GaN grown by molecular beam epitaxy (MBE). Numerical simulations are used to assist in the interpretation of SKPM images. Detailed analysis of the same area using both techniques allows imaging of surface potential variations arising from the presence of negatively charged dislocations and dislocation-related current leakage paths. Correlations between the charge state of dislocations, conductivity of leakage current paths, and possibly dislocation type can thereby be established. Approximately 25% of the leakage paths appear to be spatially correlated with negatively charged dislocation features. This is approximately the level of correlation expected due to spatial overlap of randomly distributed, distinct features of the size observed, suggesting that the negatively charged dislocations are distinct from those responsible for localized leakage paths found in GaN. The effects of charged dislocation networks on the local potential profile is modeled and discussed.

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Comparison of forward and backward SHG images using Fourier transform-second-harmonic generation imaging

Comparison of forward and backward SHG images using Fourier ...

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Conference on Lasers and Electro-Optics

作者： Rao, Raghu Ambekar Ramachandra Menta, Monal R. Leithem, Scott Toussaint Jr., Kimani C. Department of Electrical and Computer Engineering University of Illinois Urbana-Champaign IL 61820 United States Department of Mechanical Science and Engineering University of Illinois Urbana-Champaign IL 61820 United States Departments of Electrical and Computer Engineering and Bioengineering University of Illinois Urbana-Champaign IL 61820 United States

ISBN: (纸本)9781557528902

关键词： Harmonic generation

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