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Laser-mediated cartilage reshaping with feedback-controlled cryogen spray cooling: Biophysical properties and viability

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Lasers in Surgery and Medicine 2000年第1期28卷

作者： A.M. Karamzadeh BS, BA A. Rasouli BS B.S. Tanenbaum BS T.E. Milner PhD J.S. Nelson MD, PhD B.J.F. Wong MD Beckman Laser Institute and Medical Clinic University of California Irvine Irvine California 92697 Department of Engineering Harvey Mudd College Claremont California 91711 Biomedical Engineering Program Department of Electrical and Computer Engineering University of Texas at Austin Austin Texas 78712-1084 Department of Otolaryngology-Head and Neck Surgery University of California Irvine Orange California 92869

Background and Objective Recent studies have indicated that chondrocyte viability decreases with prolonged or repeated laser irradiation. To optimize laser-mediated cartilage reshaping, the heating process must be finely controlled. In this study, we use high-power Nd:YAG laser irradiation (λ = 1.32 μm) combined with cryogen spray cooling (CSC) in an attempt to reshape porcine septal cartilage while enhancing chondrocyte viability. Study Design/Materials and Methods Chondrocyte viability was determined after high-power (50 W/cm 2 ) Nd:YAG-mediated cartilage reshaping with and without cryogen spray cooling (CSC) and correlated with dynamic measurements of tissue optical and thermal properties. Results After 1.5 to 2.0 seconds of laser exposure, characteristic changes in diffuse reflectance (indicating the onset of accelerated stress relaxation) was observed in both laser only and laser with CSC specimens. After 2 seconds of laser exposure, specimens in both groups retained the curved shape for up to 14 days. After one laser exposure, chondrocyte viability was 94.35 ± 6.1% with CSC and 68.77 ± 20.1% ( P < 0.05) without CSC. After two laser exposures, a similar trend was observed with CSC (70.18 ± 16.44%) opposed to without CSC (28 ± 45%; P < 0.05). Conclusion CSC during high-power laser irradiation allows rapid heating while minimizing extreme front surface temperature elevations and axial thermal gradients. Laser irradiation with CSC can be used to effectively reshape cartilage tissue with the additional advantage of increasing chondrocyte viability. Lasers Surg. Med. 28:1–10, 2001. © 2001 Wiley-Liss, Inc.

关键词： hemocytometry otolaryngology plastic surgery reconstruction

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Effects of source traffic shaping on MPEG video transmission over next generation IP networks 8

Effects of source traffic shaping on MPEG video transmission...

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8th International Conference on computer Communications and Networks, ICCCN 1999

作者： Alam, Mohammad F. Atiquzzaman, Mohammed Karim, Mohammad A. Electro-Optics Program University of Dayton DaytonOH45469-0245 United States Department of Electrical and Computer Engineering University of Dayton DaytonOH45469-0226 United States Department of Electrical and Computer Engineering University of Tennessee KnoxvilleTN37996-2100 United States

ISBN: (纸本)0780357949

The Internet engineering Task Force (IETF) has defined the integrated services model for supporting real-time services. Guaranteed service is one of these services with firm delay and bandwidth guarantees. Before setting up a guaranteed service flow, traffic parameters of the source have to be specified in terms of token bucket traffic descriptors. The source must conform to these descriptors by shaping its traffic. In this paper, we study the effects of a token bucket traffic shaper at the source on the transmission characteristics of Motion Picture Experts Group (MPEG) video streams over the guaranteed service. For different types of MPEG video sequences, the effects of the shaper parameters on the transmission performance are studied. We develop an analytical model of the traffic shaper, and also carry out numerical simulation of the transmission performance to verify the analytical model. Our study also provides a technique to analyze stored MPEG video sequences to determine the token bucket traffic descriptors that have to be specified during flow set up. © 1999 IEEE.

关键词： Analytical models

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Finite-difference time-domain simulation of light scattering from multiple cells

Finite-difference time-domain simulation of light scattering...

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Quantum Electronics and Laser Science Conference, QELS 1999

作者： Myakov, A.V. Sergeev, A.M. Dolin, L.S. Myakov, A.V. Richards-Kortum, R. Institute of Applied Physics Russian Academy of Sciences 46 Uljanov st Nizhny Novgorod603600 Russia Biomedical Engineering program Department of Electrical and Computer Engineering University of Texas at Austin AustinTX78731 United States

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Efficient MPEG video traffic shaping for the next generation Internet

Efficient MPEG video traffic shaping for the next generation...

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IEEE Conference and Exhibition on Global Telecommunications (GLOBECOM)

作者： M.F. Alam M. Atiquzzaman M.A. Karim Electro-optics Program University of Dayton Dayton OH USA Department of Electrical and Computer Engineering University of Dayton Dayton OH USA Department of Electrical and Computer Engineering University of Tennessee Knoxville TN USA

The Internet engineering Task Force (IETF) has defined the Guaranteed Service (GS) with firm delay and bandwidth guarantees in the Integrated Services model for supporting real-time services. Before setting up a GS flow, the traffic parameter of the source have to be specified in terms of a number of token bucket traffic descriptors. The source must conform to these descriptors by shaping its traffic. In this paper we study a novel traffic shaper for efficient transmission of MPEG video streams over GS. We develop an analytical model of the traffic shaper, and also carry out numerical simulation of the transmission performance to verify the analytical model. Our study also provides a methodology to determine the token bucket traffic descriptors that have to be specified during flow set up.

关键词： Traffic control Communication system traffic control Telecommunication traffic Web and internet services Delay effects Streaming media Analytical models IP networks Transport protocols Bandwidth

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A comparison of training algorithms for DHP adaptive critic neurocontrol

A comparison of training algorithms for DHP adaptive critic ...

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International Joint Conference on Neural Networks (IJCNN)

作者： G.G. Lendaris T.T. Shannon A. Rustan Systems Science Ph.D. Program and Electrical & Computer Engineering Department Portland State University USA

A variety of alternate training strategies for implementing the dual heuristic programming (DHP) method of approximate dynamic programming in the neurocontrol context are explored. The DHP method of controller training has been successfully demonstrated by a number of authors on a variety of control problems in recent years, but no unified view of the implementation details of the method has yet emerged. A number of options are described for sequencing the training of the controller and critic networks in DHP implementations. Results are given about their relative efficiency and the quality of the resulting controllers for two benchmark control problems.

关键词： Neural networks Shape control Dynamic programming Equations Design optimization Amorphous materials Design methodology Feedback loop Supervised learning Process design

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A HIGH-RESOLUTION TIME-FREQUENCY ANALYSIS OF THE SINGING VOICE

A HIGH-RESOLUTION TIME-FREQUENCY ANALYSIS OF THE SINGING VOI...

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1999 International Workshop on Models and Analysis of Vocal Emissions for Biomedical Applications, MAVEBA 1999

作者： Mellody, Maureen Wakefield, Gregory H. Applied Physics Program 500 East University Dr. Ann ArborMI48109-1120 United States Department of Electrical Engineering and Computer Science University of Michigan 1301 Beat Ave. Ann ArborMI48109-2122 United States

We apply the modal distribution, a high-resolution time-frequency distribution, to the study of sung musical passages. Evidence is presented comparing the modal distribution with the spectrogram for a set of synthetic signals which emulate human singing. We then compare the two techniques for sung passages from four student sopranos with respect to measures of the instantaneous frequency and amplitude of the partials. In general, the modal distribution appears to be a more sensitive measure of individual differences in vocal production than the spectrogram. © 1999 Models and Analysis of Vocal Emissions for Biomedical Applications, MAVEBA 1999. All rights reserved.

关键词： Modal analysis

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Proximal femoral density patterns are consistent with bicentric joint loads

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computer Methods in Biomechanics and Biomedical engineering 1999年第4期2卷 271-283页

作者： Fischer, Kenneth J. Jacobs, Christopher R. Levenston, Marc E. Cody, Dianna D. Carters, Dennis R. Musculoskeletal Research Center Department of Orthopaedic Surgery University of Pittsburgh Pittsburgh PA 15213 United States Department of Orthopaedics Musculoskeletal Research Laboratory Pennsylvania State University School of Medicine Hershey PA 17033 United States Department of Electrical Engineering and Computer Science Continuum Elect romechanics Mhoratory Massachusetts Institute of Technology Hershey MA 02139 United States Department of Diagnostic Radiology Division of Radiologic Physics and Engineering Henry Ford Hospital Detroit MI 48202 United States Department of Veterans Affairs Medical Center Rehabilitation Research and Development Center Palo Alto CA 94304-1200 United States Department of Mechanical Engineering Stanford University Biomechanical Engineering Program Stanford CA 94305-402 United States

We developed an alternate method for density-based load estimation and applied it to estimate hip joint load distributions for two femora. Two-dimensional finite element models were constructed from single energy quantitative computed tomography (QCT) data. Load estimation was performed using five loading regions on the femoral head. Within each loading region, individual nodal loads, normal to the local surface, were supplied as input to the load estimation. An optimization procedure independently adjusted individual nodal load magnitudes in each region, and the magnitudes of muscle forces on the greater trochanter, such that the applied tissue stimulus approached the reference stimulus throughout the model. Dominant estimated load resultant directions were generally consistent with published experimental data for loads during gait. The estimated loads also suggested that loads near the extremes of the articulating surface may be important (even required) for development and maintenance of normal bone architecture. Estimated load distributions within nearly all regions predicted bicentric loading patterns, which are consistent with observations of hip joint incongruity. Remodeling simulations with the estimated loads predicted density distributions with features qualitatively similar to the QCT data sets. This study illustrates how applications of density-based bone load estimation can improve understanding of dominant loading patterns in other bones and joints. The prediction of bicentric loading suggests a very fine level of local adaptation to details of joint loading. © 1999 OPA (Overseas Publishers Association) N.V.

关键词： Finite element method

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Integrated real time multi-channel wavelength monitoring circuit using phased-array waveguide grating

Integrated real time multi-channel wavelength monitoring cir...

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Optical Fiber Communication (OFC) Conference

作者： Shan Zhong Chau-Han Lee Xiao Lin Xiao-Hui Yang Yung-Jui Chen D. Stone Department of Computer Science and Electrical Engineering And Joint Program for Advanced Electronic Materials University of Maryland Baltimore County Baltimore MD USA

An integrated multichannel wavelength monitoring circuit using specially designed phased-array waveguide grating and detector arrays, which monitors all wavelength-division multiplexing channels in real-time (sixteen ... 详细信息

ISBN: (纸本)155752582X

关键词： Circuits Gratings Wavelength division multiplexing Throughput computerized monitoring Phased arrays Wavelength measurement Detectors Sensor arrays computer science

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Performance of Turbo Trellis-Coded Modulation (T-TCM) on frequency-selective rayleigh fading channels

Performance of Turbo Trellis-Coded Modulation (T-TCM) on fre...

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1999 IEEE International Conference on Communications, ICC 1999

作者： Ha, Nguyen Hoang Rajatheva, R.M.A.P. Department of Electrical and Computer Engineering University of Manitoba WinnipegMBR3T 5V6 Canada Telecommunication Program School of Advanced Technologies Asian Institute of Technology P.O Box 4 Pathumthani12120 Thailand

ISBN: (纸本)078035284X

Turbo Trellis-Coded Modulation (T-TCM) is one of several techniques for combining turbo codes with multilevel modulation in order to save the bandwidth of the transmission systems. T-TCM was shown to perform very well on AWGN channel, but its performance over frequency-selective fading channel is still unknown. In this paper, a system model to investigate the performance of T-TCM schemes over frequency-selective fading channel is proposed. Simulation results show that when appropriate receiver is available, T-TCM also performs well on frequency-selective fading channels. T-TCM performance is much better than any other coded-modulation scheme in the past for this type of channel. © 1999 IEEE.

关键词： Turbo codes

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Recent results from the National Transparent Optical Network (NTON)

Recent results from the National Transparent Optical Network...

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IEEE Photonics Conference (IPC)

作者： H. Feng R.L. Thombley W.J. Lennon J.P. Heritage Advanced Telecommunications Program Lawrence Livemore National Laboratory Livermore CA USA Department of Electrical and Computer Engineering University of California Davis CA USA

The National Transparent Optical Network (NTON) is co-funded by the Defense Advanced Research Projects Agency (DARPA) and the National Transparent Optical Network Consortium (NTONC). Members of the NTONC include Nortel Networks, GST Telecommunications, Lawrence Livermore National Laboratories (LLNL), Sprint Communications and the Bay Area Rapid Transit District (BART). NTON provides a 10+ Gb/s open research platform for Next Generation Internet (NGI) trials. NTON is a 2000 km 10-20 Gb/s wavelength division multiplexed (WDM) network deployed using in-place commercial fiber. NTON links reach government, university and private sector labs and provide the ability to interface with most of the broadband research networks in the US. Planned interchange networks are: ATDnet, HSCC, DREN, NREN, ESnet, vBNS, SVTT, Abilene, Canarie, CalREN, and others. NTON will simultaneously support device design R&D, network R&D and testing of high bandwidth enabled applications. NTON provides direct access to nearly all of the major universities on the West Coast at data rates up to, and potentially beyond, 2.5 Gb/s. NTON will also connect major West Coast supercomputer sites, digital libraries, high energy physics labs and medical research institutions.

关键词： Optical fiber networks Wavelength division multiplexing Laboratories Internet WDM networks Optical fiber communication Optical fiber devices US Government Testing Bandwidth

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