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2005

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Full-Text Articles in Engineering

Coalition Battle Management Language (C-Bml) Study Group Final Report, Major Kevin Galvin, Mike Hieb, Andreas Tolk, Charles Turnitsa, Curtis Blais, James Montgomery Dec 2005

Coalition Battle Management Language (C-Bml) Study Group Final Report, Major Kevin Galvin, Mike Hieb, Andreas Tolk, Charles Turnitsa, Curtis Blais, James Montgomery

Computational Modeling & Simulation Engineering Faculty Publications

Interoperability across Modeling and Simulation (M&S) and Command and Control (C2) systems continues to be a significant problem for today's warfighters. M&S is well-established in military training, but it can be a valuable asset for planning and mission rehearsal if M&S and C2 systems were able to exchange information, plans, and orders more effectively. To better support the warfighter with M&S based capabilities, an open standards-based framework is needed that establishes operational and technical coherence between C2 and M&S systems.


Comments On A Proposed Change For Eurodocsis Specifications, Ron D. Katznelson Dec 2005

Comments On A Proposed Change For Eurodocsis Specifications, Ron D. Katznelson

Ron D. Katznelson

This submission provides support and explanations to the recommendation that specifications adopted for European applications of CableLabs’® Downstream RF Interface specifications (“DRFI”) should be maintained in accordance with the existing North American DRFI. It contains responses to a proposed changes offered by European proponents. This note addresses the in-channel (Active Output Channel) return loss requirements and the ‘Other Channels’ spurious and noise requirements.


Afci Quarterly Input – Unlv October 1 Through December 31, 2005, Harry Reid Center For Environmental Studies. Nuclear Science And Technology Division Dec 2005

Afci Quarterly Input – Unlv October 1 Through December 31, 2005, Harry Reid Center For Environmental Studies. Nuclear Science And Technology Division

Transmutation Research Program Reports (TRP)

Quarterly report highlighting research projects, activities and objectives of the Transmutation Research Program at the Nuclear Science & Technology Division, Harry Reid Research Center.

The University of Nevada, Las Vegas supports the AFCI through research and development of technologies for economic and environmentally sound refinement of spent nuclear fuel. The UNLV program has four components: infrastructure, international collaboration, student-based research, and management and program support.


The Implementation Of Nanoimprint Lithography For The Fabrication Of Patterned Magnetic Media, Daniel David Marks Dec 2005

The Implementation Of Nanoimprint Lithography For The Fabrication Of Patterned Magnetic Media, Daniel David Marks

Theses and Dissertations

Advances in technology are having profound effects throughout society. This is no truer than in the way information is being stored. The primary form of information storage for at least the past millennium has been paper. Today, an ever increasing amount of information is being stored electronically. An increased demand for high-performance, low-cost information storage has been a major catalyst in increasing the popularity of hard drives. In 2002, two exabytes of original information was stored on hard drives. This is ten times the amount of all printed material in the world if it were converted to electronic files. To …


An Algebraic Reconstruction Technique (Art) For The Synthesis Of Three-Dimensional Models Of Particle Aggregates From Projective Representations, Daniel Jonathan Randall-Barrot Dec 2005

An Algebraic Reconstruction Technique (Art) For The Synthesis Of Three-Dimensional Models Of Particle Aggregates From Projective Representations, Daniel Jonathan Randall-Barrot

Theses and Dissertations

There exists considerable evidence that the shear behavior and flow behavior of granular materials is significantly dependent on particle morphology. However, quantification of this dependence is a challenging task owing to a dearth of quantitative models for describing particle shape and the difficulty of modeling angular particle assemblies. The situation becomes more complex when discrete element analyses of realistic 3-D particle shapes are required. The thesis attempts to address this problem by adapting the algebraic reconstruction technique (ART) to synthesize composite 3-D granular particles from statistically obtained 3-D shape descriptors of the particles in an aggregate mixture. This thesis extends …


Analysis Of Grain Screenings By X-Ray Photoelectron Spectroscopy, Guilin Jiang, Ghaleb A. Husseini, Larry Lin Baxter, Matthew R. Linford Dec 2005

Analysis Of Grain Screenings By X-Ray Photoelectron Spectroscopy, Guilin Jiang, Ghaleb A. Husseini, Larry Lin Baxter, Matthew R. Linford

Faculty Publications

Determining the chemical structure and composition of biomass fuels using x-ray photoelectron spectroscopy XPS can provide fundamental knowledge of their structures that is useful in understanding and predicting their combustion behavior. Grain screenings are an example of an agricultural residue byproduct of food and feed production of potential interest for biomass combustion. The XPS spectra of grain screenings provide both its elemental composition and indications of its bonding. Traditional fuel analyses of this fuel are also provided. These include: ultimate analysis — the elemental composition of the overall fuel C, H, N, S, and O; chlorine analysis — reported here …


Analysis Of Sawdust By X-Ray Photoelectron Spectroscopy, Guilin Jiang, Ghaleb A. Husseini, Larry Lin Baxter, Matthew R. Linford Dec 2005

Analysis Of Sawdust By X-Ray Photoelectron Spectroscopy, Guilin Jiang, Ghaleb A. Husseini, Larry Lin Baxter, Matthew R. Linford

Faculty Publications

Determining the chemical structure and composition of biomass fuels using x-ray photoelectron spectroscopy XPS can provide fundamental knowledge of their structures that is useful in understanding and predicting their combustion behavior. Sawdust is an example of a forest product residue byproduct of paper and lumber production of potential interest for biomass combustion. The XPS spectra of sawdust provide both its elemental composition and indications of its bonding. Traditional fuel analyses of this fuel are also provided. These include: ultimate analysis — the elemental composition of the overall fuel C, H, N, S, and O; chlorine analysis — reported here as …


Analysis Of Sugar Beet Pulp By X-Ray Photoelectron Spectroscopy, Guilin Jiang, Ghaleb A. Husseini, Larry Lin Baxter, Matthew R. Linford Dec 2005

Analysis Of Sugar Beet Pulp By X-Ray Photoelectron Spectroscopy, Guilin Jiang, Ghaleb A. Husseini, Larry Lin Baxter, Matthew R. Linford

Faculty Publications

Determining the chemical structure and composition of biomass fuels using x-ray photoelectron spectroscopy XPS can provide fundamental knowledge of their structures that is useful in understanding and predicting their combustion behavior. Sugar beet pulp is an example of an agricultural residue byproduct of food and feed production of potential interest for biomass combustion. The XPS spectra of sugar beet pulp provide both its elemental composition and indications of its bonding. Traditional fuel analyses of this fuel are also provided. These include: ultimate analysis — the elemental composition of the overall fuel C, H, N, S, and O; chlorine analysis — …


Research Article| December 30 2005 Analysis Of Shea Nut Shells By X-Ray Photoelectron Spectroscopy, Guilin Jiang, Ghaleb A. Husseini, Larry Lin Baxter, Matthew R. Linford Dec 2005

Research Article| December 30 2005 Analysis Of Shea Nut Shells By X-Ray Photoelectron Spectroscopy, Guilin Jiang, Ghaleb A. Husseini, Larry Lin Baxter, Matthew R. Linford

Faculty Publications

Determining the chemical structure and composition of biomass fuels using x-ray photoelectron spectroscopy (XPS) can provide fundamental knowledge of their structures that is useful in understanding and predicting their combustion behavior. Shea nut shells are an example of an agricultural residue (byproduct of food and feed production) of potential interest for biomass combustion. The XPS spectra of shea nut shells provide both its elemental composition and indications of its bonding. Traditional fuel analyses of this fuel are also provided. These include: ultimate analysis — the elemental composition of the overall fuel (C, H, N, S, and O); chlorine analysis — …


Analysis Of Sunflower Shells By X-Ray Photoelectron Spectroscopy, Guilin Jiang, Ghaleb A. Husseini, Larry Lin Baxter, Matthew R. Linford Dec 2005

Analysis Of Sunflower Shells By X-Ray Photoelectron Spectroscopy, Guilin Jiang, Ghaleb A. Husseini, Larry Lin Baxter, Matthew R. Linford

Faculty Publications

Determining the chemical structure and composition of biomass fuels using x-ray photoelectron spectroscopy (XPS) can provide fundamental knowledge of their structures that is useful in understanding and predicting their combustion behavior. Sunflower shells are an example of an agricultural residue (byproduct of food and feed production) of potential interest for biomass combustion. The XPS spectra of sunflower shells provide both its elemental composition and indications of its bonding. Traditional fuel analyses of this fuel are also provided. These include: ultimate analysis — the elemental composition of the overall fuel (C, H, N, S, and O); chlorine analysis — reported here …


Method And System For Electronically Generating Random Answers, Stephen O. Bozzone, Bonnie Bachman Dec 2005

Method And System For Electronically Generating Random Answers, Stephen O. Bozzone, Bonnie Bachman

Economics Faculty Research & Creative Works

The invention concerns a method (300) and system (110) for electronically generating random responses in a portable electronic device (110). The method includes the steps of detecting (316) motion of the portable electronic device, in response to the detecting step, generating (318) the random response and outputting (320) the random response to a user of the portable electronic device. The method can further include the steps of prompting (312) the user to ask a question and following a predetermined time period after prompting the user to ask the question, prompting (314) the user to shake the portable electronic device. The …


Analysis Of Straw By X-Ray Photoelectron Spectroscopy, Guilin Jiang, Ghaleb A. Husseini, Larry Lin Baxter, Matthew R. Linford Dec 2005

Analysis Of Straw By X-Ray Photoelectron Spectroscopy, Guilin Jiang, Ghaleb A. Husseini, Larry Lin Baxter, Matthew R. Linford

Faculty Publications

Determining the chemical structure and composition of biomass fuels using x-ray photoelectron spectroscopy XPS can provide fundamental knowledge of their structures that is useful in understanding and predicting their combustion behavior. Straw is an example of an agricultural residue byproduct of food and feed production of potential interest for biomass combustion. The XPS spectra of straw provide both its elemental composition and indications of its bonding. Traditional fuel analyses of this fuel are also provided. These include: ultimate analysis — the elemental composition of the overall fuel C, H, N, S, and O; chlorine analysis — reported here as part …


Magnetopolaron Interactions In N-Type Indium Phosphide, R. A. Lewis, P. E. Simmonds, Y. J. Wang Dec 2005

Magnetopolaron Interactions In N-Type Indium Phosphide, R. A. Lewis, P. E. Simmonds, Y. J. Wang

Faculty of Engineering - Papers (Archive)

Broadband far-infrared absorption spectroscopy is used to investigate n-type indium phosphide in magnetic fields of up to 30 T. The large energy range 2–14 Ry and the large magnetic field range 03 employed permit the observation of a rich variety of magnetopolaron interactions. We report on the magnetopolaron effect for bound states in InP, beginning with the coupling of the 2p+ state with the 1s+LO phonon state. We further observe the magnetopolaron effect associated with the metastable state 210. In addition we report i) the re-emergence of the 210 impurity state transition beyond the LO phonon manifold, ii) the possible …


System And Method For Generating Psuedo-Noise Sequences, Sina Balkir, Walter D. Leon Salas, Michael W. Hoffman, Lance C. Pérez Dec 2005

System And Method For Generating Psuedo-Noise Sequences, Sina Balkir, Walter D. Leon Salas, Michael W. Hoffman, Lance C. Pérez

Department of Electrical and Computer Engineering: Faculty Publications

Disclosed is a method for generating psuedo-noise (PN) sequences utilizing a system comprised of a quantizer, and N directly quantized output/input map containing chaotic map cells, each in functional combination with combiner means and an m-bit shift register.


Synthesis Of Multi-Wall Carbon Nanotubes Using Unseeded Hydrocarbon Diffusion Flames, Kozo Saito, Forman A. Williams, Alvin S. Gordon, Liming Yuang Dec 2005

Synthesis Of Multi-Wall Carbon Nanotubes Using Unseeded Hydrocarbon Diffusion Flames, Kozo Saito, Forman A. Williams, Alvin S. Gordon, Liming Yuang

Mechanical Engineering Faculty Patents

A method is provided for synthesizing carbon nanotubes from unseeded methane-air diffusion flames. A novel stainless steel and Ni—Cr wire probe is also provided for collecting carbon nanotubes from those diffusion flames.


Predicted Redidual Strength Of Damaged Isotrussâ® Structures, Travis S. Carroll Dec 2005

Predicted Redidual Strength Of Damaged Isotrussâ® Structures, Travis S. Carroll

Theses and Dissertations

This thesis utilized a linear analytical approach to explore the damage tolerance or residual strength as a function of increasing damage in traditional single and hybrid-grid IsoTruss® structures. Residual strength was studied for structures subjected to axial compression, torsion and flexural bending, independently. Carbon/epoxy material properties were applied in all load cases, and fiberglass/epoxy material properties were also applied in the flexural bending case. Prior to imposing damage conditions, the IsoTruss® structures were parametrically optimized to achieve the highest strength-to-weight ratios. Typical compression strut, driveshaft, and utility pole specifications governed the design strength dimensions and boundary conditions. Damage growth was …


Adaptive Weighing Of Context Models For Lossless Data Compression, Matthew V. Mahoney Dec 2005

Adaptive Weighing Of Context Models For Lossless Data Compression, Matthew V. Mahoney

Electrical Engineering and Computer Science Faculty Publications

Until recently the state of the art in lossless data compression was prediction by partial match (PPM). A PPM model estimates the next-symbol probability distribution by combining statistics from the longest matching contiguous contexts in which each symbol value is found. We introduce a context mixing model which improves on PPM by allowing contexts which are arbitrary functions of the history. Each model independently estimates a probability and confidence that the next bit of data will be 0 or 1. Predictions are combined by weighted averaging. After a bit is arithmetic coded, the weights are adjusted along the cost gradient …


An Evolutionary Multi-Objective Crowding Algorithm (Emoca): Benchmark Test Function Results, Ramesh Rajagopalan, Chilukuri K. Mohan, Kishan G. Mehrotra, Pramod K. Varshney Dec 2005

An Evolutionary Multi-Objective Crowding Algorithm (Emoca): Benchmark Test Function Results, Ramesh Rajagopalan, Chilukuri K. Mohan, Kishan G. Mehrotra, Pramod K. Varshney

Electrical Engineering and Computer Science - All Scholarship

A new evolutionary multi-objective crowding algorithm (EMOCA) is evaluated using nine benchmark multiobjective optimization problems, and shown to produce non-dominated solutions with significant diversity, outperforming state-of-the-art multi-objective evolutionary algorithms viz., Non-dominated Sorting Genetic Algorithm – II (NSGA-II), Strength Pareto Evolutionary algorithm II (SPEA-II) and Pareto Archived Evolution Strategy (PAES) on most of the test problems. The key new approach in EMOCA is to use a diversity-emphasizing probabilistic approach in determining whether an offspring individual is considered in the replacement selection phase, along with the use of a non-domination ranking scheme. This approach appears to provide a useful compromise between the …


Reflections Of Active Galactic Nucleus Outbursts In The Gaseous Atmosphere Of M87, W. Forman, P. Nulsen, S. Heinz, F. Owen, J. Eilek, A. Vikhlinin, M. Markevitch, R. Kraft, E. Churazov, C. Jones Dec 2005

Reflections Of Active Galactic Nucleus Outbursts In The Gaseous Atmosphere Of M87, W. Forman, P. Nulsen, S. Heinz, F. Owen, J. Eilek, A. Vikhlinin, M. Markevitch, R. Kraft, E. Churazov, C. Jones

Faculty of Engineering - Papers (Archive)

We combined deep Chandra, ROSAT HRI, and XMM-Newton observations of M87 to study the impact of active galactic nucleus (AGN) outbursts on its gaseous atmosphere. Many X-ray features appear to be a direct result of repetitive AGN outbursts. In particular, the X-ray cavities around the jet and counterjet are likely due to the expansion of radio plasma, while rings of enhanced emission at 14 and 17 kpc are probably shock fronts associated with outbursts that began 1–2 × 107 yr ago. The effects of these shocks are also seen in brightenings within the prominent X-ray arms. On larger scales, ∼50 …


Identifying Common Ultrasonic Predictive Failure Signatures In Bearing Elements For The Development Of An Automated Condition Based Ultrasonic Monitoring Controller., Jason Eric Johnson Dec 2005

Identifying Common Ultrasonic Predictive Failure Signatures In Bearing Elements For The Development Of An Automated Condition Based Ultrasonic Monitoring Controller., Jason Eric Johnson

Electronic Theses and Dissertations

This thesis presents a new method for Condition Based Ultrasonic Monitoring to be applied in conjunction with a lubrication distribution controller. As part of this thesis, algorithms were developed using ultrasonic sensors to control the application of lubrication to machinery. The controller sensors detect an ultrasonic signal from rolling or sliding machine elements. This signal then alerts the controller to dispense the proper amount of lubrication when needed, as opposed to a time schedule based on average performance or history. The work from this thesis will be used to help reduce equipment downtime and maintenance cost when utilized in an …


Strong Terahertz Emission From (100) P-Type Inas, Rajind Mendis, M. L. Smith, L. J. Bignell, R. Vickers, R. A. Lewis Dec 2005

Strong Terahertz Emission From (100) P-Type Inas, Rajind Mendis, M. L. Smith, L. J. Bignell, R. Vickers, R. A. Lewis

Faculty of Engineering - Papers (Archive)

Terahertz emission has been observed from (100) Zn-acceptor-doped InAs under illumination by fs pulses of near-infrared radiation. Turning the crystal about the surface normal produces two maxima per rotation, whether the angle of incidence is 45° or 75°, in contrast to (111) p-InAs, where three maxima per rotation have been reported. The emitted terahertz power has a quadratic variation with the pump power and decreases with increasing temperature in the range 20–300 K. This behavior is consistent with a photocurrent surge being the dominant terahertz generating mechanism at low excitation fluences. The p-type InAs generates about two orders of magnitude …


An Adaptive Nonlinear Fuel Injection Control Algorithm For Motorcycle Engine, Tung-Chieh Chen, Chiu-Feng Lin, Chyuan-Yow Tseng, Chung-Ying Chen Dec 2005

An Adaptive Nonlinear Fuel Injection Control Algorithm For Motorcycle Engine, Tung-Chieh Chen, Chiu-Feng Lin, Chyuan-Yow Tseng, Chung-Ying Chen

Journal of Marine Science and Technology

The purpose of this research is to apply an adaptive fuel injection control algorithm on a motorcycle engine and evaluate its performance. A highly nonlinear switching type EGO sensor is used to measure the air fuel ratio of the engine. In the research, the nonlinear control algorithm is developed based on a Lyapunov function. Furthermore, an observer is also applied to estimate the air flow rate into the combustion room. The results show that the air fuel ratio and engine speed are stable under steady manoeuvres and the air-fuel ratio values are satisfactory.


Laminar Film Condensation On A Horizontal Plate In A Porous Medium With Surface Tension Effects, Tong-Bou Chang Dec 2005

Laminar Film Condensation On A Horizontal Plate In A Porous Medium With Surface Tension Effects, Tong-Bou Chang

Journal of Marine Science and Technology

The problem of steady filmwise condensation on a finite-size horizontal plate embedded in a porous medium is studied for the case in which a cold plate faces upwards with a dry saturation vapor. Due to the effects of surface tension forces, there is a two-phase zone lying between the liquid film and the vapor zone. As in classical filmwise condensation problems, it is assumed that; (a) the inertia within the liquid film is negligible, and (b) the properties of porous medium, dry vapor, and condensate are constant. A dimensionless parameter Boc is introduced to characterize liquid flow due to surface …


The Optimization Of The Reliability And Construction Cost Of Rc Bridges, Wen-Hu Tsao, Chi-Way Lin, Ming-Te Liang, Wen-Lung Wen-Lung Tsao Tsao Dec 2005

The Optimization Of The Reliability And Construction Cost Of Rc Bridges, Wen-Hu Tsao, Chi-Way Lin, Ming-Te Liang, Wen-Lung Wen-Lung Tsao Tsao

Journal of Marine Science and Technology

In this paper, the relationship between reliability and engineering system construction cost for obtaining optimum reliability was studied. This proposed approach was applied to the repair alternatives of existing reinforced concrete (RC) bridges for acquiring the result of optimization analysis. According to the D(degree) E(extent) R (relevancy) evaluation method, which is widely used by civil engineers in Taiwan the existing RC bridges with and without stridden rivers can be divided into 21 and 17 substructures, respectively. The use of the weighting value and the cost relation is to attain the relationship between the total engineering system construction cost and the …


Application Of Fuzzy Soil Classification In Visualizing 3-D Soil Strata, Jing-Wen Chen Dec 2005

Application Of Fuzzy Soil Classification In Visualizing 3-D Soil Strata, Jing-Wen Chen

Journal of Marine Science and Technology

The distribution of soil classes is an important factor in engineering design. In order to generate the soil class map, fuzzy soil classifications were developed to provide the means to characterize and quantify the soil classes, and then the spatial distribution of soil class can be interpolated by geostatistical method. For establishing continuous class soil maps, this paper present an index of fuzzy soil classification generated from principal component analysis (PCA). The ability of classification of the index is tested with a soil database which including 9,260 soil samples, and the accurate rate of simulation was 91.7%. There are two …


A Note On Grashof Theorem, Wen-Tung Chang, Chen-Chou Lin, Long-Iong Wu Dec 2005

A Note On Grashof Theorem, Wen-Tung Chang, Chen-Chou Lin, Long-Iong Wu

Journal of Marine Science and Technology

In this paper, Grashof’s theorem is justified from the perspective of the occurrence of stationary configurations and uncertainty configurations of four-link chains. The link length relations at stationary configurations and uncertainty configurations are examined in detail based on the triangle inequality, and then the conditions for the existence of a crank and a change point are deduced.


Monitoring Structural Degradation Of Rail Pads In Laboratory Using Impact Excitation Technique, S. Kaewunruen, Alexander Remennikov Dec 2005

Monitoring Structural Degradation Of Rail Pads In Laboratory Using Impact Excitation Technique, S. Kaewunruen, Alexander Remennikov

Faculty of Engineering - Papers (Archive)

In ballasted railway track, the deterioration of a sleeper and ballast support usually occurs due to both regular and irregular wheel/rail interactions. The repeated impact of train wheels over sleepers can reduce the lifetime of a sleeper and degrade ballast. To attenuate the effect of the impact loads on concrete sleepers, the resilient rail seat pads are used. After a certain time in service conditions, the worn rail pads have to be replaced. Assessment of the condition of rail pads is of great importance to track engineers and plays an important role in the overall track maintenance cost. A non-destructive …


Simulation Of Phonon-Assisted Band-To Band Tunneling In Carbon Nanotube Field-Effect Transistors, Siyuranga O. Koswatta, Mark S. Lundstrom, M. P. Anantram, Dmitri E. Nikonov Dec 2005

Simulation Of Phonon-Assisted Band-To Band Tunneling In Carbon Nanotube Field-Effect Transistors, Siyuranga O. Koswatta, Mark S. Lundstrom, M. P. Anantram, Dmitri E. Nikonov

Other Nanotechnology Publications

Electronic transport in a carbon nanotube metal-oxide-semiconductor field effect transistor (MOSFET) is simulated using the nonequilibrium Green’s functions method with the account of electron-phonon scattering. For MOSFETs, ambipolar conduction is explained via phonon-assisted band-to-band (Landau–Zener) tunneling. In comparison to the ballistic case, we show that the phonon scattering shifts the onset of ambipolar conduction to more positive gate voltage (thereby increasing the off current). It is found that the subthreshold swing in ambipolar conduction can be made as steep as 40 mV/decade despite the effect of phonon scattering.


Fabrication Of Various Curved Relief Structures Through Concave Surface Forming And Soft Replica Molding, Fang-Tzu Chuang Dec 2005

Fabrication Of Various Curved Relief Structures Through Concave Surface Forming And Soft Replica Molding, Fang-Tzu Chuang

Fang-Tzu Chuang

In this case, our groups presented various optical structures through the presented method, involving concave surface forming and soft replica molding. The method of concave surface forming is mainly for the fabrication of concave surface. The method of soft replica molding is mainly for the fabrication of replica. Concave and convex relief structures, including circular curved relief structures, convex relief structures with platform structures on the top, refractive beam-shaping elements, these structures with dual curvatures and asymmetric structures, can be easily made through the presented method, respectively. All processes of manufacture are in several simple steps without multistep optical lithography …


Preparative Synthesis Of Dtdp-L-Rhamnose Through Combined Enzymatic Pathways, Young Bok Abraham Kang, Yung-Hun Yang, Kwang-Won Lee, Sun-Gu Lee, Jae Kyung Sohng, Hei Chan Lee, Kwangkyoung Liou, Byung-Gee Kim Dec 2005

Preparative Synthesis Of Dtdp-L-Rhamnose Through Combined Enzymatic Pathways, Young Bok Abraham Kang, Yung-Hun Yang, Kwang-Won Lee, Sun-Gu Lee, Jae Kyung Sohng, Hei Chan Lee, Kwangkyoung Liou, Byung-Gee Kim

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

dTDP-L-rhamnose, an important precursor of O-antigen, was prepared on a large scale from dTMP by executing an one-pot reaction in which six enzymes are involved. Two enzymes, dTDP-4-keto-6-deoxy-D-glucose 3,5-epimerase and dTDP-4-keto-rhamnose reductase, responsible for the conversion of dTDP-4-keto-6-deoxy- D-glucose to dTDP-L-rhamnose, were isolated from their putative sequences in the genome of Mesorhizobium loti, functionally expressed in Escherichia coli, and their enzymatic activities were identified. The two enzymes were combined with an enzymatic process for dTDP-4- keto-6-deoxy-D-glucose involving TMP kinase, acetate kinase, dTDP-glucose synthase, and dTDP-glucose 4,6- dehydratase, which allowed us to achieve a preparative scale synthesis of dTDP-L-rhamnose using dTMP …