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2000

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Articles 361 - 390 of 2919

Full-Text Articles in Physical Sciences and Mathematics

Response Of A First-Order Stream In Maine To Short-Term In-Stream Acidification, S. A. Norton, R. Wagai, T. Navratil, J. M. Kaste, F. A. Rissberger Sep 2000

Response Of A First-Order Stream In Maine To Short-Term In-Stream Acidification, S. A. Norton, R. Wagai, T. Navratil, J. M. Kaste, F. A. Rissberger

Dartmouth Scholarship

An experimental short-term acidification with HCl at a first-order stream in central Maine, USA was used to study processes controlling the changes in stream chemistry and to assess the ability of stream substrate to buffer pH. The streambed exerted a strong buffering capacity against pH change by ion exchange during the 6-hour acidification. Streambed substrates had substantial cation and anion exchange capacity in the pH range of 4.1 to 6.5. The ion exchange for cations and SO42- were rapid and reversible. The speed of release of cations from stream substrates was Na1+> Ca2+ > Mg2+ > Al …

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On Reconfiguring Tree Linkages: Trees Can Lock, Therese Biedl, Erik D. Demaine, Martin L. Demaine, Sylvain Lazard, Anna Lubiw, Joseph O'Rourke, Steve Robbins, Ileana Streinu, Godfried Toussaint, Sue Whitesides Sep 2000

On Reconfiguring Tree Linkages: Trees Can Lock, Therese Biedl, Erik D. Demaine, Martin L. Demaine, Sylvain Lazard, Anna Lubiw, Joseph O'Rourke, Steve Robbins, Ileana Streinu, Godfried Toussaint, Sue Whitesides

Computer Science: Faculty Publications

It has recently been shown that any simple (i.e. nonintersecting) polygonal chain in the plane can be reconfigured to lie on a straight line, and any simple polygon can be reconfigured to be convex. This result cannot be extended to tree linkages: we show that there are trees with two simple configurations that are not connected by a motion that preserves simplicity throughout the motion. Indeed, we prove that an N-link tree can have 2Ω(N) equivalence classes of configurations.

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Structural Biology With Carbon Nanotube Afm Probes, Adam T. Woolley, Chin Li Cheung, Jason H. Hafner, Charles M. Lieber Sep 2000

Structural Biology With Carbon Nanotube Afm Probes, Adam T. Woolley, Chin Li Cheung, Jason H. Hafner, Charles M. Lieber

Barry Chin Li Cheung Publications

Carbon nanotubes represent ideal probes for high-resolution structural and chemical imaging of biomolecules with atomic force microscopy. Recent advances in fabrication of carbon nanotube probes with sub-nanometer radii promise to yield unique insights into the structure, dynamics and function of biological macromolecules and complexes.

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On Logistic And Some New Discrimination Rules:Charecterizations,Inference And Application., Supratik Roy Dr. Sep 2000

On Logistic And Some New Discrimination Rules:Charecterizations,Inference And Application., Supratik Roy Dr.

Doctoral Theses

Introduction and Summary Consider the problem of classification of an observation into one of two specified populations. Fisher's classification rale, just as several other rules commonly used in practice, depends only on the ratio of the individual densities fi(x), i = 1,2. This led Cox (1966),/27) to model the "posterior odds" by a simple function. Specifically,Cox's logistic discrimination (LGD) rule is then based on the statistic a + 'ßx. This has the advantage that individual densities f.(x) need not be known and we only need to estimate the parameters a and B.Another advantage, which is claimed , is that the …

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Ice Nanotube: What Does The Unit Cell Look Like?, Kenichiro Koga, Ruben D. Parra, Hideki Tanaka, Xiao Cheng Zeng Sep 2000

Ice Nanotube: What Does The Unit Cell Look Like?, Kenichiro Koga, Ruben D. Parra, Hideki Tanaka, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

It is discovered that for an n-gonal ice nanotube built from stacking a single type of n-gonal rings of water, the unit cell consists of two stacked n-gonal rings. In one ring the O–H bonds of water molecules line up clockwise whereas in the other ring the O-H bonds line up counterclockwise. Among the n-gonal ice nanotubes examined, the pentagonal or hexagonal ice nanotube appears to be the most stable.

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Environmental Finance Charette, Hyannis Park On Lewis Bay: A Case Study, New England Environmental Finance Center, Environmental Finance Center Of University Of Maryland Sep 2000

Environmental Finance Charette, Hyannis Park On Lewis Bay: A Case Study, New England Environmental Finance Center, Environmental Finance Center Of University Of Maryland

Water

The town of Yarmouth currently has a $30 million septic sludge treatment plant and transport lines in place. The vast majority of the dwellings and businesses in the Hyannis Park area are on septic systems that are viable and Title 5 compliant, regardless of age. Conventional, "non-failing" septic systems, however, were never intended to remove form their effluent nutrients such as nitrogen. These have become recognized as an environmental threat only as our understanding of the impacts of excess nutrients on ecosystems has increased in recent decades.

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Semantic Web And Information Brokering: Opportunities, Commercialization, And Challenges, Amit P. Sheth Sep 2000

Semantic Web And Information Brokering: Opportunities, Commercialization, And Challenges, Amit P. Sheth

Kno.e.sis Publications

From the chairs' report published in SIGMOD record: The keynote address entitled 'Semantic Web and Information Brokering: Opportunities, Early Commercializations, and Challenges' was delivered by Amit Sheth (University of Georgia and Taalee Corp). Sheth characterized semantics as the next step in the evolution of the WWW and stressed the importance of semantically organized information for supporting ubiquitous, powerful, accurate and efficient access to this information. Sheth also reviewed proposals for semantic interoperability frameworks such as the DAML(DARPA Agent Mark-Up Language), the Oingo family of tools for defining concepts and extracting knowledge from large databases, as well as several scenarios on …

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Managing Sprawl In The Land Of Unintended Consequences, Robert S. Bucci Sep 2000

Managing Sprawl In The Land Of Unintended Consequences, Robert S. Bucci

New England Journal of Public Policy

Americans witnessing the bulldozing of their country’s pastures, farmlands, and sensitive habitats to erect suburban housing tracts and commercial centers have come to realize that the remaining open land may be too precious to waste. Residential and commercial development is no longer quickly embraced to stimulate economic progress and prosperity. Municipalities are learning that development often extracts a price — sometimes the loss of community character and local charm, sometimes tax revenues that fall short of increased expenditures, and sometimes just plain ugliness. Responding to the new reality, many community officials have initiated unilateral ordinances regulating the development of open …

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Supernumerary Spacing Of Rainbows Produced By An Elliptical-Cross-Section Cylinder. I. Theory, James A. Lock Sep 2000

Supernumerary Spacing Of Rainbows Produced By An Elliptical-Cross-Section Cylinder. I. Theory, James A. Lock

Physics Faculty Publications

A sequence of rainbows is produced in light scattering by a particle of high symmetry in the short-wavelength Limit, and a supernumerary interference pattern occurs to one side of each rainbow. Using both a ray-tracing procedure and the Debye-series decomposition of first-order perturbation wave theory, I examine the spacing of the supernumerary maxima and minima as a function of the cylinder rotation angle when an elliptical-cross-section cylinder is normally illuminated by a plane wave. I find that the supernumerary spacing depends sensitively on the cylinder-cross-section shape, and the spacing varies sinusoidally as a function of the cylinder rotation angle for …

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Stochastic Dynamics Of Infinite-Dimensional Systems (Stochastic And Non-Linear Analysis Seminar, University Of Illinois), Salah-Eldin A. Mohammed Sep 2000

Stochastic Dynamics Of Infinite-Dimensional Systems (Stochastic And Non-Linear Analysis Seminar, University Of Illinois), Salah-Eldin A. Mohammed

Miscellaneous (presentations, translations, interviews, etc)

We describe an approach to the dynamics of non-linear stochastic differential systems with finite memory using multiplicative cocycles in Hilbert space. We introduce the notion of hyperbolicity for stationary solutions of stochastic systems with memory. We then establish the existence of smooth stable and unstable manifolds in a neighborhood of a hyperbolic stationary solution. The stable and unstable manifolds are stationary and asymptotically invariant under the stochastic semiflow. The proof uses ideas from infinite-dimensional multiplicative ergodic theory and interpolation arguments.

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Improved Signal Analysis And Time-Synchronous Reconstruction In Waveform Interpolation Coding, N. R. Chong-White, I. Burnett Sep 2000

Improved Signal Analysis And Time-Synchronous Reconstruction In Waveform Interpolation Coding, N. R. Chong-White, I. Burnett

Faculty of Informatics - Papers (Archive)

This paper presents a waveform-matched waveform interpolation (WMWI) technique which enables improved speech analysis over existing WI coders. In WMWI, an accurate representation of speech evolution is produced by extracting critically-sampled pitch periods of a time-warped, constant pitch residual. The technique also offers waveform-matching capabilities by using an inverse warping process to near-perfectly reconstruct the residual. Here, a pitch track optimisation technique is described which ensures the speech residual can be effectively decomposed and quantised. Also, the pitch parameters required to efficiently quantise and recreate the pitch track, on a period-by-period basis, are identified. This allows time-synchrony between the original …

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Exploiting Simultaneously Masked Linear Prediction In A Wi Speech Coder, Jason Lukasiak, I. Burnett Sep 2000

Exploiting Simultaneously Masked Linear Prediction In A Wi Speech Coder, Jason Lukasiak, I. Burnett

Faculty of Informatics - Papers (Archive)

This paper uses a method of incorporating simultaneous masking into the calculation of a linear predictive filter (SMLPC) as the front end to a 2 kbps waveform interpolation (WI) speech coder. A modification to the masking threshold calculation used in SMLPC is proposed. This modification improves the performance of SMLPC in noise like sections by placing greater emphasis on strongly voiced speech. MOS test results reveal that the modified SMLPC improved the perceptual quality of the WI coder. The improvement is significant for female speakers whilst the quality for male speech is virtually unchanged. This result conflicts with previous results …

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Exploring The Characteristics Of Analytic Decomposition Of Speech Signals, J Lukasiak, I. Burnett Sep 2000

Exploring The Characteristics Of Analytic Decomposition Of Speech Signals, J Lukasiak, I. Burnett

Faculty of Informatics - Papers (Archive)

This paper investigates the properties of analytic transformation of speech into envelope and phase functions. The envelope is shown to evolve slowly with the pitch of the input speech, whilst the phase consists of two components; one evolving slowly with pitch and another that exhibits a more rapid evolution. We investigate decomposing the phase component further using two distinct methods: (a) filtering of the phase in the pitch evolutionary direction and (b) performing a second analytic decomposition of the phase into secondary envelope and phase components. To examine the characteristics of the pitch cycle evolution, the analytic transform is employed …

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Very Low Rate Speech Coding Using Temporal Decomposition And Waveform Interpolation, C. H. Ritz, I. Burnett, J Lukasiak Sep 2000

Very Low Rate Speech Coding Using Temporal Decomposition And Waveform Interpolation, C. H. Ritz, I. Burnett, J Lukasiak

Faculty of Informatics - Papers (Archive)

In very low rate coding the aim is to accurately represent speech characteristics as efficiently as possible. High coding gains for the spectral features can be achieved through the use of temporal decomposition. Waveform interpolation coders accurately represent the excitation using characteristic waveforms (CWs) extracted at a constant rate. In this paper, the two approaches are combined into a very low rate coder operating at around 1 kbps. It is shown that the evolution of the excitation is related to the evolution of the speech spectrum. To minimise bit rates, the transmission of CWs is adapted to the spectral parameter …

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Measurements Of Excess O3, Co2, Co, Ch4, C2h4, C2h2, Hcn, No, Nh3, Hcooh, Ch3cooh, Hcho, And Ch3oh In 1997 Alaskan Biomass Burning Plumes By Airborne Fourier Transform Infrared Spectroscopy (Aftir), Jon G. Goode, Robert J. Yokelson, Darold E. Ward, Ronald A. Susott, Ronald E. Babbitt, Mary Ann Davies, Wei Min Hao Sep 2000

Measurements Of Excess O3, Co2, Co, Ch4, C2h4, C2h2, Hcn, No, Nh3, Hcooh, Ch3cooh, Hcho, And Ch3oh In 1997 Alaskan Biomass Burning Plumes By Airborne Fourier Transform Infrared Spectroscopy (Aftir), Jon G. Goode, Robert J. Yokelson, Darold E. Ward, Ronald A. Susott, Ronald E. Babbitt, Mary Ann Davies, Wei Min Hao

Chemistry and Biochemistry Faculty Publications

We used an airborne Fourier transform infrared spectrometer (AFTIR), coupled to a flow-through, air-sampling cell, on a King Air B-90 to make in situ trace gas measurements in isolated smoke plumes from four, large, boreal zone wildfires in interior Alaska during June 1997. AFTIR spectra acquired near the source of the smoke plumes yielded excess mixing ratios for 13 of the most common trace gases: water, carbon dioxide, carbon monoxide, methane, nitric oxide, formaldehyde, acetic acid, formic acid, methanol, ethylene, acetylene, ammonia and hydrogen cyanide. Emission ratios to carbon monoxide for formaldehyde, acetic acid, and methanol were 2.2±0.4%, 1.3±0.4%, and …

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Analysis Of The Nico2O4 Spinel Surface With Auger And X-Ray Photoelectron Spectroscopy, J.-G. Kim, D. L. Pugmire, D. Battaglia, Marjorie Langell Sep 2000

Analysis Of The Nico2O4 Spinel Surface With Auger And X-Ray Photoelectron Spectroscopy, J.-G. Kim, D. L. Pugmire, D. Battaglia, Marjorie Langell

Marjorie A. Langell Publications

Nickel cobaltite, NiCo2O4, has been synthesized by sol–gel and thermal decomposition techniques and the surface composition studied with Auger (AES) and X-ray photoelectron spectroscopies (XPS). The asintroduced samples are near-stoichiometric, although samples fabricated by thermal decomposition tend to be oxygen-defi cient by approximately 25% of the predicted spinel concentration. Nickel 2p XPS indicates the predominant form of the metal to be Ni2+, with the cations located in octahedral sites. The cobalt cations are equally divided between tetrahedral and octahedral sites as Co3+. The oxygen XP 1s spectrum is composed of two peaks, …

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Evaluation Of A Vancomycin Chiral Stationary Phase In Capillary Electrochromatography Using Polar Organic And Reversed-Phase Modes, Charlotte Karlsson, Lars Karlsson, Daniel W. Armstrong, Paul K. Owens Sep 2000

Evaluation Of A Vancomycin Chiral Stationary Phase In Capillary Electrochromatography Using Polar Organic And Reversed-Phase Modes, Charlotte Karlsson, Lars Karlsson, Daniel W. Armstrong, Paul K. Owens

Chemistry Faculty Research & Creative Works

A vancomycin chiral stationary phase (CSP) was fully evaluated in capillary electrochromatography (CEC) in reversed phase and polar organic modes for a number of racemic pharmaceutical compounds. High efficiency and resolution values were obtained for a number of compound classes including thalidomide in both the polar organic mode (190 000 plates meter-1 and Rs = 13.8) and reversed-phase mode (125 000 plates meter-1 and Rs = 13.0). Experimental parameters, including organic modifier, organic solvent ratio, ionic strength, pH, temperature, and voltage, were examined in both the aqueous and nonaqueous modes to deduce their effect on the resultant EOF, retention times, …

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Rapid Identification Of The Bacterial Pathogens Responsible For Urinary Tract Infections Using Direct Injection Ce, Daniel W. Armstrong, Jeffrey M. Schneiderheinze Sep 2000

Rapid Identification Of The Bacterial Pathogens Responsible For Urinary Tract Infections Using Direct Injection Ce, Daniel W. Armstrong, Jeffrey M. Schneiderheinze

Chemistry Faculty Research & Creative Works

The use of high-performance capillary electrokinetic techniques for the separation, identification, and quantitation of intact microbes represents a new frontier for separation science. In this work, it is demonstrated that pathogens most responsible for urinary tract infections can be distinguished from one another after direct injection of untreated urine. High efficiencies (often exceeding 1 000 000 plates/m) and short analysis times (< 10 min) are characteristics of this approach. The concentration of the urine matrix appears to be able to cause a small, but definite, change in the electroosmotic flow velocity. This high-efficiency separation-based approach could prove to be invaluable for the diagnosis and tracking of certain diseases. It also could form the basis for a variety of rapid microbial assays.

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Resolving Ambiguities In Gravity Wave Propagation Directions Inherent In Satellite Observations: A Simulation Study, Michael P. Hickey Ph.D., Jason S. Brown Sep 2000

Resolving Ambiguities In Gravity Wave Propagation Directions Inherent In Satellite Observations: A Simulation Study, Michael P. Hickey Ph.D., Jason S. Brown

Publications

We simulate space-based, sub-limb viewing observations of airglow brightness fluctuations caused by atmospheric gravity wave interactions with the O2 atmospheric airglow, and we demonstrate that, due to the geometry associated with such observations, the brightness fluctuations observed for the optically thick 0–0 band emission will always appear stronger for waves traveling towards the observer (satellite). The effect should be most noticeable for waves having relatively small vertical wavelengths (∼10 km) and horizontal wavelengths of 50 km or greater. For waves of short (∼100 km) horizontal wavelength, the brightness fluctuation anisotropy with respect to viewing direction may also be evident in …

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Field Trip Guide (For The Nebraska Well Drillers Association) Eastern Nebraska Geology, Scott Summerside, Duane Eversoll, Mark Kuzila, Matt Joeckel Sep 2000

Field Trip Guide (For The Nebraska Well Drillers Association) Eastern Nebraska Geology, Scott Summerside, Duane Eversoll, Mark Kuzila, Matt Joeckel

Conservation and Survey Division

No abstract provided.

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Quest For Tilings On Riemann Surfaces Of Genus Six And Seven, Robert Dirks, Maria Sloughter Sep 2000

Quest For Tilings On Riemann Surfaces Of Genus Six And Seven, Robert Dirks, Maria Sloughter

Mathematical Sciences Technical Reports (MSTR)

The problem of kaleidoscopically tiling a surface by congruent triangles is equivalent to finding groups generated in certain ways. In order to admit a tiling, a group must have a specific set of generators as well as an involutary automorphism, T, that acts to reverse the orientation of the tiles. The purpose of this paper is to explore group theoretic and computational methods for determining the existence of symmetry groups and tiling groups, as well as to classify the symmetry and tiling groups on hyperbolic Riemann surfaces of genus 6 and 7.

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Electroweak Quantum Chemistry For Possible Precursor Molecules In The Evolution Of Biomolecular Homochirality, Robert Berger, Martin Quack, Gregory S. Tschumper Sep 2000

Electroweak Quantum Chemistry For Possible Precursor Molecules In The Evolution Of Biomolecular Homochirality, Robert Berger, Martin Quack, Gregory S. Tschumper

Chemistry Faculty Research & Creative Works

The unified 'electroweak' theory of the electromagnetic and weak nuclear interactions in physics predicts a small energy difference (ΔE(pv)) between the left- and right-handed enantiomers of chiral molecules. Thus, electroweak theory provides one of several possible explanations for the origin of biomolecular homochirality (nature's preference for L-amino acids and D-monosaccharides). Recent systematic electroweak quantum-chemical studies find ΔE(pv) to be an order of magnitude larger than previously anticipated, which has sparked renewed interest in the subject. The present paper addresses, for the first time, the question of the relative stability of certain possible prebiotic precursor molecules suggested in the work of …

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Changes In Bacterioplankton Metabolic Capabilities Along A Salinity Gradient In The York River Estuary, Virginia, Usa, G. E. Schultz, H. W. Ducklow Sep 2000

Changes In Bacterioplankton Metabolic Capabilities Along A Salinity Gradient In The York River Estuary, Virginia, Usa, G. E. Schultz, H. W. Ducklow

VIMS Articles

Changes in metabolic capabilities of bacterial communities along the estuarine salinity gradient may affect the extent of organic matter processing and bacterial growth and accumulation during transit through the system; As part of a larger study of estuarine microbial processes, we attempted to quantify differences in bacterial community structure using Biolog plates. Biolog GN plates (Biolog, Inc., Hayward, CA, USA) were used to determine differences in bacterioplankton community metabolic potential. Biolog GN microplates are 96-well microtiter plates in which each well contains an individual carbon source as well the redox dye tetrazolium violet. As bacteria grow and oxidize each substrate, …

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The Effects Of Sulfuric Acid On The Mechanical Properties Of Ice Single Crystals, Y. L. Trickett, I. Baker, P. M.S Pradhan Sep 2000

The Effects Of Sulfuric Acid On The Mechanical Properties Of Ice Single Crystals, Y. L. Trickett, I. Baker, P. M.S Pradhan

Dartmouth Scholarship

Ice single crystals of various orientations containing various concentrations of H2SO4 up to 11.5 ppm were cut from large pucks of laboratory-grown ice. Constant-strain-rate compression tests were performed on the doped ice crystals both at −20°C at an axial strain rate of 1 × 10−5 s−1 and at −10°C at 1 × 106 s−1. The stress–strain curves showed a linearly rising stress with increasing strain, followed by a sharply declining stress after reaching a peak. With further strain, the sharp decline in stress slowed. The tests clearly showed, for the first time, that this naturally occurring impurity dramatically decreases both …

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Dynamical Properties Of Forced Shear Layers In An Annular Geometry, Evangelos A. Coutsias, Keith Bergeron, J.P. Lynov, A.H. Nielsen Sep 2000

Dynamical Properties Of Forced Shear Layers In An Annular Geometry, Evangelos A. Coutsias, Keith Bergeron, J.P. Lynov, A.H. Nielsen

Branch Mathematics and Statistics Faculty and Staff Publications

Results of numerical simulations of a forced shear flow in an annular geometry are presented. The particular geometry used in this work reduces the effects of centrifugal and Coriolis forces. However, there are still a large number of system parameters (shear width, shear profile, radius of curvature, initial conditions, etc.) to characterize. This set of variables is limited after the code has been validated with experimental results (Rabaud & Couder 1983; Chomaz et al. 1988) and with the associated linear stability analysis. As part of the linear stability characterization, the pseudo-spectrum for the associated Orr-Sommerfeld operator for plane, circular Couette …

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A Theory For Stretchiness, Brandon R. Brown Sep 2000

A Theory For Stretchiness, Brandon R. Brown

Physics and Astronomy

No abstract available.

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Conductivity Of Irradiated Pure Water, Jerry Goodisman, Rick Blades Sep 2000

Conductivity Of Irradiated Pure Water, Jerry Goodisman, Rick Blades

Chemistry - All Scholarship

The conductivity of water having parts per billion concentrations of oxygen, hydrogen, and bicarbonate was measured while the water was irradiated by a low-pressure mercury vapor lamp, which was turned on and off periodically. A cell normally used for measurement of dissolved oxidizable carbon was modified for use in these measurements. When the lamp is turned on, the conductivity increases (sometimes decreases) with a time constant of about 50 ms; when the lamp is turned off, the conductivity changes in the opposite direction with a time constant of about 275 ms, but does not return to its value before the …

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Optically Simulating A Quantum Associative Memory, Dan A. Ventura, John C. Howell, John A. Yeazell Sep 2000

Optically Simulating A Quantum Associative Memory, Dan A. Ventura, John C. Howell, John A. Yeazell

Faculty Publications

This paper discusses the realization of a quantum associative memory using linear integrated optics. An associative memory produces a full pattern of bits when presented with only a partial pattern. Quantum computers have the potential to store large numbers of patterns and hence have the ability to far surpass any classical neural network realization of an associative memory. In this work two 3-qubit associative memories will be discussed using linear integrated optics. In addition, corrupted, invented and degenerate memories are discussed.

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Optically Simulating A Quantum Associative Memory, John C. Howell, John A. Yeazell, Dan Ventura Sep 2000

Optically Simulating A Quantum Associative Memory, John C. Howell, John A. Yeazell, Dan Ventura

Mathematics, Physics, and Computer Science Faculty Articles and Research

This paper discusses the realization of a quantum associative memory using linear integrated optics. An associative memory produces a full pattern of bits when presented with only a partial pattern. Quantum computers have the potential to store large numbers of patterns and hence have the ability to far surpass any classical neural-network realization of an associative memory. In this work two three-qubit associative memories will be discussed using linear integrated optics. In addition, corrupted, invented and degenerate memories are discussed.

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Effect Of Collagen Turnover On The Accumulation Of Advanced Glycation End Products, Nicole Verzijl, Jeroen Degroot, Suzanne R. Thorpe, Ruud A. Bank, J. Nikki Shaw, Timothy J. Lyons, Johannes Wj Bijlsma, Floris Pjg Lafeber, John W. Baynes, Johan M. Tekoppele Sep 2000

Effect Of Collagen Turnover On The Accumulation Of Advanced Glycation End Products, Nicole Verzijl, Jeroen Degroot, Suzanne R. Thorpe, Ruud A. Bank, J. Nikki Shaw, Timothy J. Lyons, Johannes Wj Bijlsma, Floris Pjg Lafeber, John W. Baynes, Johan M. Tekoppele

Faculty Publications

Collagen molecules in articular cartilage have an exceptionally long lifetime, which makes them susceptible to the accumulation of advanced glycation end products (AGEs). In fact, in comparison to other collagen-rich tissues, articular cartilage contains relatively high amounts of the AGE pentosidine. To test the hypothesis that this higher AGE accumulation is primarily the result of the slow turnover of cartilage collagen, AGE levels in cartilage and skin collagen were compared with the degree of racemization of aspartic acid (% D-Asp, a measure of the residence time of a protein). AGE (Ne- (carboxymethyl)lysine, Ne-(carboxyethyl)lysine, and pentosidine) and % D-Asp concentrations increased …

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