Digital Commons Network^™

Coherence Properties Near Interfaces Of Random Media, A. Apostol, A. Dogariu

Faculty Bibliography 2000s

The spatial coherence theory of optical fields radiated by statistically homogeneous, infinite, planar sources does not account for detailed surface characteristics. However, coherence properties change with the angular distribution of the intensity radiated from such a source, which, in turn, depends on the physical properties of the sample. We show that second-order correlations of the optical field measured at several wavelengths away from the surface of a highly inhomogeneous medium relate to the statistical characteristics of the interface.

Palladium Nanoparticle Arrays Using Template-Assisted Electrodeposition, D. Bera, S. C. Kuiry, S. Patil, University Of Central Florida

Faculty Bibliography 2000s

Palladium nanoparticles are being increasingly considered as room-temperature hydrogen sensors and storage materials. Pd nanoparticle arrays have been synthesized using template-assisted electrodeposition. The template based on Al film on a polymeric substrate was characterized by scanning electron microscopy and energy dispersive spectroscopy. X-ray photoelectron spectroscopy study confirmed that the deposited nanoparticles were of metallic Pd. High-resolution transmission electron microscopy investigation revealed that Pd nanoparticles consisted of a large number of nanocrystallites in the size range of 5-10 nm.

Transforming Education, Transforming Ourselves: Contributions And Lessons Learned, Karen L. Biraimah

Faculty Bibliography 2000s

No abstract provided.

Incoherent White Light Solitons In Logarithmically Saturable Noninstantaneous Nonlinear Media, H. Buljan, A. Šiber, M. Soljacic, T. Schwartz, M. Segev, Demetrios N. Christodoulides

Faculty Bibliography 2000s

We analytically demonstrate the existence of white light solitons in logarithmically saturable noninstantaneous nonlinear media. This incoherent soliton has elliptic Gaussian intensity profile, and elliptic Gaussian spatial correlation statistics. The existence curve of the soliton connects the strength of the nonlinearity, the spatial correlation distance as a function of frequency, and the characteristic width of the soliton. For this soliton to exist, the spatial correlation distance must be smaller for larger temporal frequency constituents of the beam.

Characterization Of A Novel And Specific Inhibitor For The Pro-Apoptotic Protease Omi/Htra2, Lucia Cilenti, Younghee Lee, Sibylle Hess, Srinivasa Srinivasula, Kwon Moo Parrk, Daniela Junqueira, Hedvika Davis, Joseph V. Bonventre, Emad S. Alnemri, Antonis S. Zervos

Faculty Bibliography 2000s

Omi/HtrA2 is a mammalian serine protease with high homology to bacterial HtrA chaperones. Omi/HtrA2 is localized in mitochondria and is released to the cytoplasm in response to apoptotic stimuli. Omi/HtrA2 induces cell death in a caspase-dependent manner by interacting with the inhibitor of apoptosis protein as well as in a caspase-independent manner that relies on its protease activity. We describe the identification and characterization of a novel compound as a specific inhibitor of the proteolytic activity of Omi/HtrA2. This compound (ucf-101) was isolated in a high throughput screening of a combinatorial library using bacterially made Omi-(134-458) protease and fluorescein-casein as …

Angle Dependent Magnetization Reversal Of Thin Film Magnetic Recording Media, Kevin R. Coffey, Thomas Thomson, Jan-Ulrich Thiele

Faculty Bibliography 2000s

The results of angular measurements of the remanent switching fields for granular longitudinal and perpendicular magnetic recording media are presented and compared to idealized models of magnetic switching. Co alloy longitudinal and perpendicular recording media are found primarily to have a Stoner-Wohlfarth switching character at vibrating sample magnetometer time scales. Since the Stoner-Wohlfarth model does not consider the effects of thermal activation, the angular dependence of the time independent switching field H-swro(theta) was determined from a Sharrock analysis. This approach shows a closer agreement between experimental data and model. For the case of a representative high density longitudinal recording medium, …

Lattice Solitons In Bose-Einstein Condensates, Nikolaos K. Efremidis, Demetrios N. Christodoulides

Faculty Bibliography 2000s

We systematically study the properties of lattice solitons in Bose-Einstein condensates with either attractive or repulsive atom interactions. This is done, by exactly solving the mean-field Gross-Pitaevskii equation in the presence of a periodic potential. We find new families of lattice soliton solutions that are characterized by the position of the energy eigenvalue within the associated band structure. These include lattice solitons in condensates with either attractive or repulsive atom interactions that exist in finite or semi-infinite gaps, as well as nonlinear modes that exhibit atomic population cutoffs.

Potential Involvement Of Extracellular Signal-Regulated Kinase 1 And 2 In Encystation Of A Primitive Eukaryote, Giardia Lamblia - Stage-Specific Activation And Intracellular Localization, John G. Ellis Iv, Monica Davila, Ratna Chakrabarti

Faculty Bibliography 2000s

Mitogen-activated protein kinase (MAPK) pathways are major signaling systems by which eukaryotic cells convert environmental cues to intracellular events such as proliferation and differentiation. We have identified Giardia lamblia homologues of two members of the MAPK family ERK1 and ERK2. Functional characterization of giardial ERK1 and ERK2 revealed that both kinases were expressed in trophozoites and encysting cells as 44- and 41-kDa polypeptides, respectively, and were catalytically active. Analysis of the kinetic parameters of the recombinant proteins showed that ERK2 is similar to5 times more efficient than ERK1 in phosphorylating myelin basic protein as a substrate, although the phosphorylating efficiency …

A General Paradigm To Model Reaction-Based Biogeochemical Processes In Batch Systems, Yilin Fang, Gour-Tsyh Yeh, William D. Burgos

Faculty Bibliography 2000s

[1] This paper presents the development and illustration of a numerical model of reaction-based geochemical and biochemical processes with mixed equilibrium and kinetic reactions. The objective is to provide a general paradigm for modeling reactive chemicals in batch systems, with expectations that it is applicable to reactive chemical transport problems. The unique aspects of the paradigm are to simultaneously (1) facilitate the segregation (isolation) of linearly independent kinetic reactions and thus enable the formulation and parameterization of individual rates one reaction by one reaction when linearly dependent kinetic reactions are absent, (2) enable the inclusion of virtually any type of …

Simulations Of Liquid-Crystal Fabry-Perot Etalons By An Improved 4x4 Matrix Method, Yuhua Huang, Thomas X. Wu, Shin-Tson Wu

Faculty Bibliography 2000s

The optical performances of a liquid crystal (LC) Fabry-Perot (FP) etalon in various configurations were simulated by a faster 4 x 4 matrix method. Results show that the FP with a 90degrees twisted nematic LC is polarization. insensitive if the applied voltage exceeds similar to3X of the Freedericksz transition threshold. This method can well depict the transmission spectra of the FP cavity and, therefore, is useful for optimizing the FP tunable filters for telecommunications.

Discrete Vector Solitons In Two-Dimensional Nonlinear Waveguide Arrays: Solutions, Stability, And Dynamics, J. Hudock, P. G. Kevrekidis, B. A. Malomed, Demetrios N. Christodoulides

Faculty Bibliography 2000s

We identify and investigate bimodal (vector) solitons in models of square-lattice arrays of nonlinear optical waveguides. These vector self-localized states are, in fact, self-induced channels in a nonlinear photonic-crystal matrix. Such two-dimensional discrete vector solitons are possible in waveguide arrays in which each element carries two light beams that are either orthogonally polarized or have different carrier wavelengths. Estimates of the physical parameters necessary to support such soliton solutions in waveguide arrays are given. Using Newton relaxation methods, we obtain stationary vector-soliton solutions, and examine their stability through the computation of linearized eigenvalues for small perturbations. Our results may also …

Second Harmonic Generation Tuning Curves In Quasiphase-Matched Potassium Titanyl Phosphate With Narrow, High-Intensity Beams, Mordechai Katz, David Eger, Hongki Kim, Ladislav Jankovic, George Stegeman, Silvia Carrasco, Lluis Torner

Faculty Bibliography 2000s

The second harmonic generation (SHG) tuning curves with temperature and angle of incidence were measured in periodically poled KTiOPO4 for narrow fundamental beams at intensities typical of quadratic soliton generation. Mutual self-focusing of the fundamental and harmonic, cascading, and walk-off for light incidence away from the poling axis, drastically distorted the SHG response curves, in good agreement with theory.

Second Harmonic Generation, Beam Dynamics And Spatial Soliton Generation In Periodically Poled Ktiopo4, H. Kim, L. Jankovic, G. Stegeman, S. Carrasco, L. Torner, M. Katz, D. Eger

Faculty Bibliography 2000s

Spatial solitons were investigated in periodically poled KTiOPO4 under conditions of second harmonic generation and many new features associated with soliton generation in quasi-phase-matched samples were observed. The effects on the second harmonic generation tuning curves of the beam narrowing mechanisms responsible for soliton generation were found to be dramatic. It was demonstrated experimentally that the mutual collapse of the fundamental and harmonic beams is a complex phenomenon.

Body Image Among Older, Rural, African-American Women With Type 2 Diabetes, Leslie Sue Lieberman, Claudia K. Probart, Nancy E. Schoenberg

Faculty Bibliography 2000s

Type 2 diabetes and obesity co-occur in high prevalence among African-American women. The positive value placed on large body size has both historic and contemporary biosocial relevance. The maintenance of weight at medically recommended levels is a cornerstone of both prevention and treatment of Type 2 diabetes. This study of overweight, elderly, rural African-American women with 7 pe 2 diabetes found they generally preferred smaller body sizes compared to previous studies. Normal to slim body images as presented in a photographic array were selected as being more attractive, less likely to have diabetes and hypertension, healthier and to be more …

Properties Of Quadratic Multi-Soliton Generation Near Phase-Match In Periodically Poled Potassium Titanyl Phosphate, Sergey Polyakov, Ladislav Jankovic, Hongki Kim, George Stegeman, Silvia Carrasco, Lluis Torner, Mordechai Katz

Faculty Bibliography 2000s

The properties of the multi-quadratic-soliton generation process have been investigated both theoretically and experimentally near and on phase-match in non-critically-phase-matched, periodically poled, potassium titanyl phosphate (PPKTP). It was found that multi-soliton generation occurs primarily due to asymmetry in the input beam and at phase-matching. The number of solitons generated depended on the input intensity in a non-trivial way.

Cloning Of Hbsag-Encoded Genes In Different Vectors And Their Expression In Eukaryotic Cells, Shan Qin, Hong Tang, Lian-San Zhao, Fang He, Yong Lin, Li Liu, Xiao-Mei He

Faculty Bibliography 2000s

AIM: To compare the efficiency of different plasmids as DNA vectors by cloning three HBsAg-encoded genes into two eukaryotic expression vectors, pRc/CMV and pSG5UTPL/Flag, and to express HBsAg S, MS, and LS proteins in SP2/0 cells, and to establish monoclone SP2/0 cell strains that are capable of expressing S or S2S proteins stably. METHODS: Segments of S, preS2-S, preS1-preS2-S genes of Hepatitis B virus were amplified by routine PCR and preS1-S fragment was amplified by Over-Lap Extension PCR. The amplified segments were cleaved with restricted endonuclease Hind III/Not I followed by ligation with pRc/CMV, or BamHI/EcoR I followed by ligation …

Dependence Of Two-Photon-Absorption-Excited Fluorescence On The Angle Between The Linear Polarizations Of Two Intersecting Beams, Alexandra Rapaport, Ferenc Szipocs, Michael Bass

Faculty Bibliography 2000s

We report experimental observation of the dependence of the fluorescence excited by two-photon absorption (TPA/E fluorescence) in dye solutions on the angle between the linear polarizations of two intersecting pump beams. Both degenerate and nondegenerate TPA/E fluorescence were studied with 4 ns pulsed tunable lasers as pump sources. We find that earlier theoretical analyses do not contain all of the observed changes in fluorescence signal with relative polarization angle.

Limiting Aspect Ratios Of Sagnac Interferometers, R. Glenn Sellar, Glenn D. Boreman

Faculty Bibliography 2000s

Any two-beam interferometer may be employed as a Fourier transform spectrometer. The two most commonly used for Fourier transform spectrometry are the Michelson interferometer and the Sagnac interferometer, the relative merits of which have been discussed in the literature. Typically, it is the interferometer that limits the acceptable range of angles for the input beam, and this maximum acceptance angle in turn limits the etendue, and hence limits the responsivity of the instrument when viewing an extended source. In designs where the interferometer is in a diverging or converging beam, the allowable range of input angles limits the focal ratio …

Attenuation Of Mycobacterium Tuberculosis By Disruption Of A Mas-Like Gene Or A Chalcone Synthase-Like Gene, Which Causes Deficiency In Dimycocerosyl Phthiocerol Synthesis, Tatiana D. Sirakova, Vinod S. Dubey, Michael H. Cynamon, Pappachan E. Kolattukudy

Faculty Bibliography 2000s

Tuberculosis is one of the leading preventable causes of death. Emergence of drug-resistant tuberculosis makes the discovery of new targets for antimyrobacterial drugs critical. The unique mycobacterial cell wall lipids are known to play an important role in pathogenesis, and therefore the genes responsible for their biosynthesis offer potential new targets. To assess the possible role of some of the genes potentially involved in cell wall lipid synthesis, we disrupted a mas-like gene, msl7, and a chalcone synthase-like gene, pks10, with phage-mediated delivery of the disruption construct, in which the target gene was disrupted by replacement of an internal segment …

The Largest Open Reading Frame (Pks12) In The Mycobacterium Tuberculosis Genome Is Involved In Pathogenesis And Dimycocerosyl Phthiocerol Synthesis, Tatianna D. Sirakova, Vinod S. Dubey, Hwa-Jung Kim, Michael H. Cynamon, Pappachan E. Kolattukudy

Faculty Bibliography 2000s

The cell wall lipids in Mycobacterium tuberculosis are probably involved in pathogenesis. The largest open reading frame in the genome of M. tuberculosis H37Rv, pks12, is unique in that it encodes two sets of domains needed to produce fatty acids. Apks12-disrupted mutant was produced, and disruption was confirmed by both PCR analysis and Southern blotting. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed that a 430-kDa protein band present in the wild type was missing in the mutant. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MS) and liquid chromatography (LC)-MS analysis of tryptic peptides showed that 54 peptides distributed …

Pore Size Distribution, Survival Probability, And Relaxation Time In Random And Ordered Arrays Of Fibers, Manolis M. Tomadakis, Teri J. Robertson

Faculty Bibliography 2000s

We present a random walk based investigation of the pore size probability distribution and its moments, the survival probability and mean survival time, and the principal relaxation time, for random and ordered arrays of cylindrical fibers of various orientation distributions. The dimensionless mean survival time, principal relaxation time, mean pore size, and mean square pore size are found to increase with porosity, remain practically independent of the directionality of random fiber beds, and attain lower values for ordered arrays. Wide pore size distributions are obtained for random fiber structures and relatively narrow for ordered square arrays, all in very good …

Eigenmodes Of A Reflective Twisted-Nematic Liquid-Crystal Cell, Xinyu Zhu, Qi Hong, Yuhua Huang, Shin-Tson Wu

Faculty Bibliography 2000s

The eigenmodes of a reflective twisted-nematic liquid-crystal (TN LC) cell are analyzed based on the Jones matrix method. Two models are developed to describe the LC system in the low- and high-voltage regimes. The simulated transmission spectra of LC Fabry-Perot etalons are used to investigate the eigenmodes. In a general reflective TN LC cell, the eigenmodes are two orthogonal linear polarization states. Under some specific conditions, these two linear polarization states will approach the bisector or orthogonal to the bisector of the TN LC cell. This bisector effect is useful for reducing the operating voltage and enhancing the contrast ratio …

Antenna-Coupled Infrared Focal Plane Array, Francisco Javier Gonzalez

Retrospective Theses and Dissertations

In this dissertation a new type of infrared focal plan array (IR FPA) was investigated, consisting of antenna-coupled microbolometer fabricated using electron-beam lithography. Four different antenna designs were experimentally demonstrated at 10-micron wavelength: dipole, bowtie, square-spiral, and log-periodic. The main differences between these antenna types were their bandwidth, collection area, angular reception pattern, and polarization. To provide pixel collection areas commensurate with typical IR FPA requirements, two configurations were investigated: a two-dimensional serpentine interconnection of individual IR antennas, and a Fresnel-zone-plate (FZP) coupled to a single-element antenna. Optimum spacing conditions for the two-dimensional interconnect were developed. Increased sensitivity was demonstrated …

The Effect Of The 2000 Election On Low-Income African American Voters, Barbara Compton Abney

Retrospective Theses and Dissertations

This research answers the question, "What impact did the 2000 election have on low-income African American voters and how will it affect turnout in future elections?"

The analysis focuses on the predominantly black, low-income community of Parramore and examine issues of efficacy related to the 2000 presidential election and beyond. The analysis consists of survey distributed through various community service agencies and conducted door-to-door in Parramore. Respondents were asked a series of questions related to past voter participation, trust in government, the fairness of the 2000 election and perceived future participation. The responses of the survey were compiled into a …

University Of Central Florida Libraries, Annual Report 2002-2003, Ucf Libraries

Libraries' Documents

No abstract provided.

Apparatus, System, And Method For Extracting An Optical Clock Signal From An Optical Data Signal, Guifang Li, Weiming Mao

UCF Patents

This invention is related to clock extraction of NRZ signals and clock of NRZ and RZ signals. It consists of a nonlinear device that produces frequency, and a frequency discriminator. The current invention is useful for clock

Display Medium Using Emitting Particles Dispersed In A Transparent Host, Michael Bass, Hans Jennsen

UCF Patents

Two and three dimensional color image displays. The displays include a display medium having a substantially uniform dispersion of red, green and blue visible light emitting particles sized between approximately 0.5 to approximately 50 microns therethrough. The particles can be dye doped polymethylmethacrylate(pmma) plastic, and the display medium can be pmma, acrylic plastic or glass. Other particles can be used such as rare earth doped crystals. The two dimensional display uses three laser sources each having different wavelengths that direct light beams to each of three different types of particle in the display medium. Light is absorbed by the particles …

University Of Central Florida Commencement, December 13 & 14, 2002, University Of Central Florida

Commencement Programs

No abstract provided.

Roone Arledge: A Tribute, Richard C. Crepeau

On Sport and Society

The death of Roone Arledge this past week marks the passing of one those remarkable figures in recent history who had a major influence on mass culture in America. He changed the viewing habits of Americans, transformed the way in which television covers sport, altered the nature and character of American sport, and transformed the way in which television presents reality to the American public. For all of these reasons Roone Arledge cast a large shadow over America in the second half of the twentieth century.

Central Florida Future, Vol. 35 No. 29, November 25, 2002

Central Florida Future

Students receive a taste of hunger: Banquet addresses real-world poverty; Hitt's raise pushes him to the top; Higher athletic fee to improve sports teams.