Current Search: zhang (x)
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Title
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Performance analysis of wireless communication systems in multipath fading environments with correlated shadowing and co-channel interference.
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Creator
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Zhang, Jingjun., Florida Atlantic University, Aalo, Valentine A., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
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Abstract/Description
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The performance aspects of conventional cellular (FDMA/TDMA) and CDMA systems with micro- and macroscopic diversity reception are investigated in a severe mobile communication environment which is characterized by path loss, correlated lognormal shadowing, multipath fading, background noise and interference. Under a co-channel interference-limited assumption, an exact analytical expression for the co-channel interference (CCI) probability is presented for a macroscopic diversity system with...
Show moreThe performance aspects of conventional cellular (FDMA/TDMA) and CDMA systems with micro- and macroscopic diversity reception are investigated in a severe mobile communication environment which is characterized by path loss, correlated lognormal shadowing, multipath fading, background noise and interference. Under a co-channel interference-limited assumption, an exact analytical expression for the co-channel interference (CCI) probability is presented for a macroscopic diversity system with an arbitrary number of correlated macroscopic branches. For noise-limited systems, the average bit-error-rate (BER) and outage probability performances of a narrowband mobile communication system with micro- and macrodiversity reception are evaluated. In the relevant analysis, both Nakagami and Rician fading channels are considered. When both co-channel interference and noise coexists, the results for a Nakagami fading channel show that diversity reception can be used to reduce the effects of interference while combating fading and shadowing. Micro- and macroscopic diversities are also applied to a multicell DS-CDMA system. In a conventional cellular system with macroscopic diversity, the mobile user is usually connected to the closest base station. However, a base-station selection scheme based on a least attenuation criterion is shown to provide a significant performance improvement over the conventional system. In this case, the system performance is examined in terms of BER and outage probability, while accounting for the effects of path loss, correlated shadowing, multipath fading, multiple access interference, and imperfect power control.
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Date Issued
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1999
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PURL
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http://purl.flvc.org/fcla/dt/12600
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Subject Headings
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Wireless communication systems, Code division multiple access
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Format
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Document (PDF)
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Title
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Targeted Gene Knock-out Via Promoter Tagging in Tomato (Lycopersicon Esculentum) and Tobacco (Nicotiana Tabacum).
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Creator
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Kazy, Alia, Zhang, Xing-Hai, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
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Abstract/Description
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Many different ways to create mutants have been established. This research demonstrates yet another variation of the promoter tagging technique that allows for a single step selection of the putative transgenic plants that have a mutation in constitutively expressed genes. While tomato transformants have not yet been convincingly confirmed, tobacco transformation resulted in seven transgenic lines showing resistance to high concentrations of kanamycin. Two transgenic lines were further...
Show moreMany different ways to create mutants have been established. This research demonstrates yet another variation of the promoter tagging technique that allows for a single step selection of the putative transgenic plants that have a mutation in constitutively expressed genes. While tomato transformants have not yet been convincingly confirmed, tobacco transformation resulted in seven transgenic lines showing resistance to high concentrations of kanamycin. Two transgenic lines were further investigated and three putative promoters isolated. Transient expression analysis of leaves transformed by particle bombardment with vectors carrying beta-glucuronidase gene driven by these putative promoters suggests two of them to be functional. Further investigation is needed to confirm the expression in the stably transformed plants as well as cloning of the genes downstream of the functional promoters and research of their functions.
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Date Issued
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2007
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PURL
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http://purl.flvc.org/fau/fd/FA00000779
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Subject Headings
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Gene mapping--Methodology, Gene mapping--Data processing, Gene expression, Microbial genetics, Computational biology
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Format
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Document (PDF)
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Title
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XYZ: A scalable, partially centralized lookup service for large-scale peer-to-peer systems.
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Creator
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Zhang, Jianying., Florida Atlantic University, Wu, Jie, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
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Abstract/Description
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Peer-to-Peer (P2P) systems are characterized by direct access between peer computers, rather than through a centralized server. File sharing is the dominant P2P application on the Internet, allowing users to easily contribute, search and obtain content. The objective of this thesis was to design XYZ, a partially centralized, scalable and self-organizing lookup service for wide area P2P systems. The XYZ system is based on distributed hash table (DHT). A unique ID and a color assigned to each...
Show morePeer-to-Peer (P2P) systems are characterized by direct access between peer computers, rather than through a centralized server. File sharing is the dominant P2P application on the Internet, allowing users to easily contribute, search and obtain content. The objective of this thesis was to design XYZ, a partially centralized, scalable and self-organizing lookup service for wide area P2P systems. The XYZ system is based on distributed hash table (DHT). A unique ID and a color assigned to each node and each file. The author uses clustering method to create the system backbone by connecting the cluster heads together and uses color clustering method to create color overlays. Any lookup for a file with a color will only be forwarded in the color overlay with the same color so that the searching space is minimized. Simulations and analysis are also provided in this thesis.
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Date Issued
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2005
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PURL
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http://purl.flvc.org/fcla/dt/13263
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Subject Headings
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Wireless communication systems, Peer-to-peer architecture (Computer networks), Computational grids (Computer systems)
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Format
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Document (PDF)
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Title
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A VLSI implementable thinning algorithm.
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Creator
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Zhang, Wei, Florida Atlantic University, Shankar, Ravi, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
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Abstract/Description
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Thinning is a very important step in a Character Recognition System. This thesis evolves a thinning algorithm that can be hardware implemented to improve the speed of the process. The software thinning algorithm features a simple set of rules that can be applied on both hexagonal and orthogonal character images. The hardware architecture features the SIMD structure, simple processing elements and near neighbor communications. The algorithm was simulated against the U.S. Postal Service...
Show moreThinning is a very important step in a Character Recognition System. This thesis evolves a thinning algorithm that can be hardware implemented to improve the speed of the process. The software thinning algorithm features a simple set of rules that can be applied on both hexagonal and orthogonal character images. The hardware architecture features the SIMD structure, simple processing elements and near neighbor communications. The algorithm was simulated against the U.S. Postal Service Character Database. The architecture, evolved with consideration of both the software constraints and the physical layout limitations, was simulated using VHDL hardware description language. Subsequent to VLSI design and simulations the chip was fabricated. The project provides for a feasibility study in utilizing the parallel processor architecture for the implementation of a parallel image thinning algorithm. It is hoped that such a hardware implementation will speed up the processing and lead eventually to a real time system.
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Date Issued
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1992
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PURL
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http://purl.flvc.org/fcla/dt/14837
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Subject Headings
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Optical character recognition devices--Computer simulation, Algorithms, Integrated circuits--Very large scale integration
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Format
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Document (PDF)
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Title
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The development and application of a numerical model for predicting the frequency response of the seabed from vertical profiles of sediment impedance.
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Creator
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Zhang, Jian Long., Florida Atlantic University, Schock, Steven G., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
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Abstract/Description
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Interaction of normal incidence, wideband acoustic pulses with seabed is investigated to determine the acoustic frequency ranges that provide the most information about the sediment structure. An exact numerical model is developed for calculating the frequency response and impulse response of the seabed from an impedance profile of a sediment core. A database of impedance profiles from several ocean environments were studied to describe the shapes of commonly found impedance changes. The...
Show moreInteraction of normal incidence, wideband acoustic pulses with seabed is investigated to determine the acoustic frequency ranges that provide the most information about the sediment structure. An exact numerical model is developed for calculating the frequency response and impulse response of the seabed from an impedance profile of a sediment core. A database of impedance profiles from several ocean environments were studied to describe the shapes of commonly found impedance changes. The impulse response of the seabed is convolved with acoustic pulses to generate synthetic acoustic returns. The synthetic profiles are studied to determine the effect of operating frequency and bandwidth on resolution and on the accuracy of measuring impedance changes. This thesis explains why inversion procedures have failed to generate vertical impedance profiles of the seabed from normal incidence reflection data. The results of this work provide guidelines for selecting subbottom profiler array sizes and operating frequencies for quantitative sediment studies, and for subsampling cores.
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Date Issued
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1996
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PURL
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http://purl.flvc.org/fcla/dt/15293
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Subject Headings
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Marine sediments--Acoustic properties, Seismic reflection method
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Format
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Document (PDF)
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Title
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A parallel and reliable robot controller system.
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Creator
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Zhang, Ruiguang., Florida Atlantic University, Fernandez, Eduardo B., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
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Abstract/Description
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In recent years robots have become increasingly important in many areas. Along with the development of robot-arm control theory, there has been an increased demand for faster and more reliable control systems. In this thesis, a parallel technique is applied to all of the units of a robot control system. Also, software fault-tolerance mechanisms such as timeout, conversation, exception handling, and their Occam implementations, are considered. A simulation study shows that pipelining, together...
Show moreIn recent years robots have become increasingly important in many areas. Along with the development of robot-arm control theory, there has been an increased demand for faster and more reliable control systems. In this thesis, a parallel technique is applied to all of the units of a robot control system. Also, software fault-tolerance mechanisms such as timeout, conversation, exception handling, and their Occam implementations, are considered. A simulation study shows that pipelining, together with a multiprocessing system, increases the performance of this real-time system, and it is a convenient way to speed up robot controller execution. While we have not evaluated the increase in reliability, we have shown that these fault tolerance mechanisms can be conveniently implemented in this type of application.
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Date Issued
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1989
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PURL
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http://purl.flvc.org/fcla/dt/14566
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Subject Headings
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Control theory, Robots--Programming
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Format
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Document (PDF)
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Title
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Stochastic earthquake ground motion modeling.
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Creator
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Zhang, Ruichong., Florida Atlantic University, Lin, Y. K., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
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Abstract/Description
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A model for earthquake ground motion is developed in this dissertation using principles of geophysics and stochastics. The earth is idealized as being composed of horizontally stratified layers, with uniform physical properties for each layer. The seismic source is assumed to be the result of shear dislocation propagating on a fault line, which is further discretized into a series of point sources at equal intervals. The fundamental problem of the ground motion in a layered medium due to a...
Show moreA model for earthquake ground motion is developed in this dissertation using principles of geophysics and stochastics. The earth is idealized as being composed of horizontally stratified layers, with uniform physical properties for each layer. The seismic source is assumed to be the result of shear dislocation propagating on a fault line, which is further discretized into a series of point sources at equal intervals. The fundamental problem of the ground motion in a layered medium due to a point source at a given source location is first considered. The governing equations of three-dimensional wave motion in a uniform layer are presented and solved in both Cartesian and cylindrical coordinates. Wave propagation in a multi-layered medium is then analyzed in detail, in which the wave scattering matrices are introduced so that stability and accuracy in numerical calculation can be guaranteed. A detailed review of the mechanism of seismic point source is also provided. Based on the fundamental solution for a point source, an earthquake model is constructed by superposing the solutions associated with a series of point sources along a line which are activated sequentially at random times. Statistical characteristics of earthquake ground motion is then obtained by applying a generalized version of the random-pulse-train theory and its evolutionary spectral representation. Finally the effects of uneven interface on the earthquake ground motion is also analyzed using a first-order perturbation approach.
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Date Issued
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1992
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PURL
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http://purl.flvc.org/fcla/dt/12290
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Subject Headings
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Earth movements, Earthquakes, Stochastic processes
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Format
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Document (PDF)
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Title
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SALT MARSH SPECIES CLASSIFICATION AND SOIL PROPERTY MODELING USING MULTIPLE REMOTE SENSORS.
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Creator
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Nicholson, Heather M., Zhang, Caiyun, Florida Atlantic University, Department of Geosciences, Charles E. Schmidt College of Science
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Abstract/Description
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Salt marshes are highly dynamic ecosystems that rely on multiple environmental and physical drivers that determine species distribution and soil property distribution. However, climate change and human interference are threatening the delicate ecosystem. One of the easiest ways to monitor marsh dynamics is through remote sensing. Traditional methods may not handle the large, non-parametric datasets well and often do not spatially determine areas of uncertainty. This dissertation research...
Show moreSalt marshes are highly dynamic ecosystems that rely on multiple environmental and physical drivers that determine species distribution and soil property distribution. However, climate change and human interference are threatening the delicate ecosystem. One of the easiest ways to monitor marsh dynamics is through remote sensing. Traditional methods may not handle the large, non-parametric datasets well and often do not spatially determine areas of uncertainty. This dissertation research developed a framework to map marsh species and predict ground soil properties using multiple remote sensing data sources by integrating modern Object-based Image Analysis (OBIA), machine learning, data fusion, and band indices techniques. It also sought to determine areas of uncertainty in the final outputs and differences between different spectral resolutions. Five machine learning classifiers were examined including Support Vector Machine (SVM) and Random Forest (RF) to map marsh species. Overall results illustrated that RF and SVM typically performed best, especially when using hyperspectral data combined with DEM information. Seven regressors were assessed to map three different soil properties. Again, RF and SVM performed the best no matter the dataset used, or soil property mapped. Soil salinity had r as high as 0.93, soil moisture had r as high as 0.91, and soil organic an r as high as 0.74 when using hyperspectral data.
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Date Issued
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2022
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PURL
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http://purl.flvc.org/fau/fd/FA00014000
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Subject Headings
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Salt marshes, Salt marsh ecology, Species, Remote sensing
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Format
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Document (PDF)
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Title
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Analysis of KED-mediated wound response to biotic stress and mechanical damage in tomato plants (Solanum lycopersicum).
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Creator
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Nifakos, Nicholas, Zhang, Xing-Hai, Florida Atlantic University, Department of Biological Sciences, Charles E. Schmidt College of Science
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Abstract/Description
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Lysine-rich KED was previously identified from wounded tobacco (Nicotiana tabacum) leaves before the alignment of protein sequences between NtKED (Nicotiana tabacum KED) and SlKED (Solanum lycopersicum KED) were discovered to display 55.1% identity. Using previously generated SlKED knockout plants by CRISPR/Cas9, we performed biological assays, to investigate the role of KED in wound response to biotic and abiotic stress. Previous studies implied that the KED gene functions as a role in the...
Show moreLysine-rich KED was previously identified from wounded tobacco (Nicotiana tabacum) leaves before the alignment of protein sequences between NtKED (Nicotiana tabacum KED) and SlKED (Solanum lycopersicum KED) were discovered to display 55.1% identity. Using previously generated SlKED knockout plants by CRISPR/Cas9, we performed biological assays, to investigate the role of KED in wound response to biotic and abiotic stress. Previous studies implied that the KED gene functions as a role in the wound-induced mechanism, as well as suggested that it may also function in the plant defense system against biotic stress and insect herbivory. The results from bioassays using tobacco hornworm (Manduca sexta) have proven inconclusive thus far. Expression of KED is induced not only by mechanical wounding but also by touching such as brushing the leaves, indicating that this gene is sensitive to subtle environmental signal and may be involved in defense response against abiotic stress. To further investigate the KED gene’s role in the plant defense system, biological assays using both specialist and generalist herbivores, transcription analysis using various phytohormone mutant plants, and Evans blue cellular damage assays were performed. Our findings imply that the KED gene does not seem to have a long-term effect on insect herbivory but may have a shortterm anti-feeding effect against insect herbivores. Results from the Evans blue membrane damage assay indicate the KED gene may provide some benefit to mechanically damaged plants in a short-term period post-wounding of leaf tissues. Using the SlKED knockout as genetic tool, we conclude that this gene does not confer resistance to insect herbivores over a long-term but seems to provide a beneficial defense response in the short-term. Our membrane damage assay results also imply that this gene may be involved in membrane stabilization and repair of cellular damage after mechanical wounding.
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Date Issued
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2022
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PURL
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http://purl.flvc.org/fau/fd/FA00014001
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Subject Headings
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Plant gene expression, Solanum lycopersicum, Tomatoes--Effect of stress on
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Format
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Document (PDF)
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Title
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QUANTIFICATION OF PERMAFROST THAW DEPTH AND SNOW DEPTH IN INTERIOR ALASKA AT MULTIPLE SCALES USING FIELD, AIRBORNE, AND SPACEBORNE DATA.
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Creator
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Brodylo, David, Zhang, Caiyun, Florida Atlantic University, Department of Geosciences, Charles E. Schmidt College of Science
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Abstract/Description
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Much of Interior Alaska contains permafrost, which is a permanently frozen layer found within or at the surface of the Earth. Historically, this permafrost has experienced relative stability, with limited thaw during warmer summer months and fire events. However, largely due to the impact of a warming climate, among other factors, permafrost that would typically experience limited thawing during the summer season has recently been thawing at an unprecedented rate. Trapped by this layer of...
Show moreMuch of Interior Alaska contains permafrost, which is a permanently frozen layer found within or at the surface of the Earth. Historically, this permafrost has experienced relative stability, with limited thaw during warmer summer months and fire events. However, largely due to the impact of a warming climate, among other factors, permafrost that would typically experience limited thawing during the summer season has recently been thawing at an unprecedented rate. Trapped by this layer of permafrost is a large quantity of carbon (C), which could be released into the atmosphere as greenhouse gases such as carbon dioxide (CO2) and methane (CH4). Due to the remoteness of the Arctic, there is a lack of yearly recorded permafrost thaw depth and snow depth values across much of the region. As such, the focus of this research was to establish a framework to identify how permafrost thaw depth and snow depth can be predicted across both a 1 km2 local scale and a 100 km2 regional scale in Interior Alaska by a combination of 1 m2 field data, airborne and spaceborne remote sensing products, and object-based machine learning techniques from 2014 – 2022. Machine learning techniques Random Forest, Support Vector Machine, k-Nearest Neighbor, Multiple Linear Regression, and Ensemble Analysis were applied to predict the permafrost thaw depth and snow depth. Results indicated that this methodology was able to successfully upscale both the 1 m2 field permafrost thaw depth and snow depth data to a 1 km2 local scale before successfully further upscaling the estimated results to a 100 km2 regional scale, while also linking the estimated values with ecotypes. The best results were produced by Ensemble Analysis, which tended to have the highest Pearson’s Correlation Coefficient, alongside the lowest Mean Absolute Error and Root Mean Square Error. Both Random Forest and k-Nearest Neighbor also provided encouraging results. The presence or absence of a thick canopy cover was strongly connected with thaw depth and snow depth estimates. Image resolution was an important factor when upscaling field data to the local scale, however it was overall less critical for further upscaling to the regional scale.
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Date Issued
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2023
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PURL
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http://purl.flvc.org/fau/fd/FA00014229
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Subject Headings
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Permafrost--Alaska, Remote sensing, Machine learning
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Format
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Document (PDF)
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Title
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Analysis of Tobacco Resistance to Saline Conditions via Endogenous Expression of SeNN24 gene from the halophyte plant Salicornia europaea.
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Creator
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Wynter, Lij, Zhang, Xing-Hai, Florida Atlantic University, Department of Biological Sciences, Charles E. Schmidt College of Science
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Abstract/Description
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Freshwater salinization and expanding desertification threaten global agriculture. Promise lies in salt resistance genes found in Salicornia europaea, a halophyte that thrives in high-salt conditions partly due to protein action. We focused one of its genes, SeNN24. It enhanced salt resistance in yeast and shows promise in improving crop resilience. Our research introduced SeNN24 into tobacco via agrobacterial transformation, testing the plants under salt and drought conditions. The...
Show moreFreshwater salinization and expanding desertification threaten global agriculture. Promise lies in salt resistance genes found in Salicornia europaea, a halophyte that thrives in high-salt conditions partly due to protein action. We focused one of its genes, SeNN24. It enhanced salt resistance in yeast and shows promise in improving crop resilience. Our research introduced SeNN24 into tobacco via agrobacterial transformation, testing the plants under salt and drought conditions. The transformed tobacco showed superior tolerance of up to 400mM NaCl and drought, maintaining health and even flowering under stress. This suggests that SeNN24 could potentially confer significant salt and drought resistance to vital crops, protecting them from environmental challenges and enhancing agricultural sustainability.
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Date Issued
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2024
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PURL
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http://purl.flvc.org/fau/fd/FA00014441
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Subject Headings
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Halophytes, Tobacco, Salinity, Botany
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Format
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Document (PDF)
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Title
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IDENTIFYING AREAS AT RISK OF CLIMATE GENTRIFICATION IN TAMPA CITY.
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Creator
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Ramirez, David Alexander, Zhang, Caiyun, Florida Atlantic University, Department of Geosciences, Charles E. Schmidt College of Science
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Abstract/Description
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Gentrification describes rapid infrastructure development and investment in areas with lower income classes. It may cause potential erasure of the original neighborhood's unique culture and the displacement of residents. Due to rising sea levels and the increase in the frequency and intensity of storms, the inundation of Florida will increase as time passes. This creates an ironic relationship where historical coastal areas inhabited by an affluent population will move inland to historically...
Show moreGentrification describes rapid infrastructure development and investment in areas with lower income classes. It may cause potential erasure of the original neighborhood's unique culture and the displacement of residents. Due to rising sea levels and the increase in the frequency and intensity of storms, the inundation of Florida will increase as time passes. This creates an ironic relationship where historical coastal areas inhabited by an affluent population will move inland to historically lower-income populations. This thesis developed a Climate Gentrification Index (CGI) to identify areas at risk of gentrification caused by inundation of storm scenarios in Tampa City, Florida. Socioeconomic data and inundation data produced from a hydrological model were combined to define CGI and areas with high risk were mapped and discussed.
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Date Issued
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2024
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PURL
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http://purl.flvc.org/fau/fd/FA00014397
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Subject Headings
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Gentrification, Tampa (Fla.), Climate change
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Format
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Document (PDF)
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Title
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Evaluating the Impact of LiDAR DEM Uncertainties on Inundation Modeling in Coastal Sub-Watersheds: An Exploration Via Deterministic and Probabilistic Approaches.
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Creator
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Thapa, Madan Chhetri, Zhang, Caiyun, Su, Hongbo, Florida Atlantic University, Department of Geosciences, Charles E. Schmidt College of Science
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Abstract/Description
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This study examines the impact of uncertainty associated with Light Detection and Ranging (LiDAR) derived Digital Elevation Models (DEMs) on flood risk mapping in the North Biscayne Bay sub-watershed. A comparison of flood extent and generation of the probability of flooding was carried out using the bathtub and probabilistic approaches respectively. The water level was computed separately for original and refined DEM using Cascade 2001 hydrological model. Using land cover based corrected...
Show moreThis study examines the impact of uncertainty associated with Light Detection and Ranging (LiDAR) derived Digital Elevation Models (DEMs) on flood risk mapping in the North Biscayne Bay sub-watershed. A comparison of flood extent and generation of the probability of flooding was carried out using the bathtub and probabilistic approaches respectively. The water level was computed separately for original and refined DEM using Cascade 2001 hydrological model. Using land cover based corrected DEMs reveals a 12% reduction in flooded areas in contrast to original DEM, considering uncertainties associated with land cover. Probabilistic flood modeling via Gaussian Geostatistical Simulation accounts for DEM uncertainty, yielding nuanced probability flood risk maps (0-100%). Findings emphasize DEM refinement before conducting flood mapping to address uncertainties. Future research should explore other mediums of correction incorporating effects of point density of LiDAR, methods of DEM generation, use of diverse scenarios, and kriging techniques for flood modeling and mapping while using LiDAR derived DEM.
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Date Issued
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2024
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PURL
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http://purl.flvc.org/fau/fd/FA00014476
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Subject Headings
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Biscayne Bay (Fla.), Lidar, Digital elevation models
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Format
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Document (PDF)
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Title
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The Lack of CuZnSOD Leads to Impaired Neurotransmitter Release, Neuromuscular Junction Destabilization and Reduced Muscle Strength in Mice.
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Creator
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Shi, Yun, Ivannikov, Maxim V., Walsh, Michael E., Liu, Yuhong, Zhang, Yiqiang, Jaramillo, Carlos A., Macleod, Gregory, Van Remmen, Holly, Phillips, William
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Abstract/Description
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Elevated reactive oxygen species (ROS) production and ROS-dependent protein damage is a common observation in the pathogenesis of many muscle wasting disorders, including sarcopenia. However, the contribution of elevated ROS levels to –a breakdown in neuromuscular communication and muscle atrophy remains unknown. In this study, we examined a copper zinc superoxide dismutase [CuZnSOD (Sod1)] knockout mouse (Sod1-/-), a mouse model of elevated oxidative stress that exhibits accelerated loss of...
Show moreElevated reactive oxygen species (ROS) production and ROS-dependent protein damage is a common observation in the pathogenesis of many muscle wasting disorders, including sarcopenia. However, the contribution of elevated ROS levels to –a breakdown in neuromuscular communication and muscle atrophy remains unknown. In this study, we examined a copper zinc superoxide dismutase [CuZnSOD (Sod1)] knockout mouse (Sod1-/-), a mouse model of elevated oxidative stress that exhibits accelerated loss of muscle mass, which recapitulates many phenotypes of sarcopenia as early as 5 months of age. We found that young adult Sod1-/- mice display a considerable reduction in hind limb skeletal muscle mass and strength when compared to age-matched wild-type mice. These changes are accompanied by gross alterations in neuromuscular junction (NMJ) morphology, including reduced occupancy of the motor endplates by axons, terminal sprouting and axon thinning and irregular swelling. Surprisingly however, the average density of acetylcholine receptors in endplates is preserved. Using in vivo electromyography and ex vivo electrophysiological studies of hind limb muscles in Sod1-/- mice, we found that motor axons innervating the extensor digitorum longus (EDL) and gastrocnemius muscles release fewer synaptic vesicles upon nerve stimulation. Recordings from individually identified EDL NMJs show that reductions in neurotransmitter release are apparent in the Sod1-/- mice even when endplates are close to fully innervated. However, electrophysiological properties, such as input resistance, resting membrane potential and spontaneous neurotransmitter release kinetics (but not frequency) are similar between EDL muscles of Sod1-/- and wild-type mice. Administration of the potassium channel blocker 3,4-diaminopyridine, which broadens the presynaptic action potential, improves both neurotransmitter release and muscle strength. Together, these results suggest that ROS-associated motor nerve terminal dysfunction is a contributor to the observed muscle changes in Sod1-/- mice.
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Date Issued
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2014-06-27
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PURL
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http://purl.flvc.org/fau/fd/FAUIR000036
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Format
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Citation
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Title
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Paper and Flexible Substrates as Materials for Biosensing Platforms to Detect Multiple Biotargets.
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Creator
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Shafiee, Hadi, Asghar, Waseem, Inci, Fatih, Yuksekkaya, Mehmet, Jahangir, Muntasir, Zhang, Michael H., Durmus, Naside Gozde, Gurkan, Umut Atakan, Kuritzkes, Daniel R., Demirci, Utkan
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Date Issued
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2015-08-06
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PURL
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http://purl.flvc.org/fau/flvc_fau_islandoraimporter_10.1038_srep08719_1630600934
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Format
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Citation
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Title
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The Coordination Dynamics of Multiple Agents.
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Creator
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Zhang, Mengsen, Tognoli, Emmanuelle, Kelso, J. A. Scott, Florida Atlantic University, Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences
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Abstract/Description
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A fundamental question in Complexity Science is how numerous dynamic processes coordinate with each other on multiple levels of description to form a complex whole - a multiscale coordinative structure (e.g. a community of interacting people, organs, cells, molecules etc.). This dissertation includes a series of empirical, theoretical and methodological studies of rhythmic coordination between multiple agents to uncover dynamic principles underlying multiscale coordinative structures. First,...
Show moreA fundamental question in Complexity Science is how numerous dynamic processes coordinate with each other on multiple levels of description to form a complex whole - a multiscale coordinative structure (e.g. a community of interacting people, organs, cells, molecules etc.). This dissertation includes a series of empirical, theoretical and methodological studies of rhythmic coordination between multiple agents to uncover dynamic principles underlying multiscale coordinative structures. First, a new experimental paradigm was developed for studying coordination at multiple levels of description in intermediate-sized (N = 8) ensembles of humans. Based on this paradigm, coordination dynamics in 15 ensembles was examined experimentally, where the diversity of subjects movement frequency was manipulated to induce di erent grouping behavior. Phase coordination between subjects was found to be metastable with inphase and antiphase tendencies. Higher frequency diversity led to segregation between frequency groups, reduced intragroup coordination, and dispersion of dyadic phase relations (i.e. relations at di erent levels of description). Subsequently, a model was developed, successfully capturing these observations. The model reconciles the Kuramoto and the extended Haken-Kelso-Bunz model (for large- and small-scale coordination respectively) by adding the second-order coupling from the latter to the former. The second order coupling is indispensable in capturing experimental observations and connects behavioral complexity (i.e. multistability) of coordinative structures across scales. Both the experimental and theoretical studies revealed multiagent metastable coordination as a powerful mechanism for generating complex spatiotemporal patterns. Coexistence of multiple phase relations gives rise to many topologically distinct metastable patterns with di erent degrees of complexity. Finally, a new data-analytic tool was developed to quantify complex metastable patterns based on their topological features. The recurrence of topological features revealed important structures and transitions in high-dimensional dynamic patterns that eluded its non-topological counterparts. Taken together, the work has paved the way for a deeper understanding of multiscale coordinative structures.
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Date Issued
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2018
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PURL
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http://purl.flvc.org/fau/fd/FA00013111
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Subject Headings
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Complexity science, Coordination dynamics, Nonlinear Dynamics, Nonlinear systems and complexity
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Document (PDF)
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Title
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Guidelines for monitoring autophagy in Caenorhabditis elegans.
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Creator
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Hong Zhang, Jessica T Chang, Bin Guo, Malene Hansen, Kailiang Jia, Attila L Kovács, Caroline Kumsta, Louis R Lapierre, Renaud Legouis, Long Lin, Qun Lu, Alicia Meléndez, Eyleen J O'Rourke, Ken Sato, Miyuki Sato, Xiaochen Wang, Fan Wu
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Abstract/Description
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The cellular recycling process of autophagy has been extensively characterized with standard assays in yeast and mammalian cell lines. In multicellular organisms, numerous external and internal factors differentially affect autophagy activity in specific cell types throughout the stages of organismal ontogeny, adding complexity to the analysis of autophagy in these metazoans. Here we summarize currently available assays for monitoring the autophagic process in the nematode C. elegans. A...
Show moreThe cellular recycling process of autophagy has been extensively characterized with standard assays in yeast and mammalian cell lines. In multicellular organisms, numerous external and internal factors differentially affect autophagy activity in specific cell types throughout the stages of organismal ontogeny, adding complexity to the analysis of autophagy in these metazoans. Here we summarize currently available assays for monitoring the autophagic process in the nematode C. elegans. A combination of measuring levels of the lipidated Atg8 ortholog LGG-1, degradation of well characterized autophagic substrates such as germline P granule components and the SQSTM1/p62 ortholog SQST-1, expression of autophagic genes and electron microscopy analysis of autophagic structures are presently the most informative, yet steady-state, approaches available to assess autophagy levels in C. elegans. We also review how altered autophagy activity affects a variety of biological processes in C. elegans such as L1 survival under starvation conditions, dauer formation, aging, and cell death, as well as neuronal cell specification. Taken together, C. elegans is emerging as a powerful model organism to monitor autophagy while evaluating important physiological roles for autophagy in key developmental events as well as during adulthood.
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Date Issued
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2015
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PURL
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http://purl.flvc.org/fau/fd/FAUIR000529
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Format
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Document (PDF)
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Title
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In search of MMP specific inhibitors: protein engineering of TIMPs.
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Creator
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Bahudhanapati, Harinathachari., Charles E. Schmidt College of Science, Department of Biomedical Science
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Abstract/Description
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The tissue inhibitors of metalloproteinases (TIMPs) are endogenous inhibitors of the matrix metalloproteinases (MMPs). Since unregulated MMP activities are linked to arthritis, cancer, and atherosclerosis, TIMP variants that are selective inhibitors of disease-related MMPs have potential therapeutic value. The structures of TIMP/MMP complexes reveal that most interactions with the MMP involve the N-terminal region of TIMP and the C-D B-strand connector which occupy the primed (right side of...
Show moreThe tissue inhibitors of metalloproteinases (TIMPs) are endogenous inhibitors of the matrix metalloproteinases (MMPs). Since unregulated MMP activities are linked to arthritis, cancer, and atherosclerosis, TIMP variants that are selective inhibitors of disease-related MMPs have potential therapeutic value. The structures of TIMP/MMP complexes reveal that most interactions with the MMP involve the N-terminal region of TIMP and the C-D B-strand connector which occupy the primed (right side of the active site) and unprimed (left side) regions of the active site. Substitutions for Thr2 of N-TIMP- 1 strongly influence MMP selectivity. In this study we found that Arg and Gly, which generally reduce MMP affinity, have less effect on binding to MMP-9. When the Arg mutation is added to the NTIMP-1 mutant with AB loop of TIMP-2, it produced a gelatinase-specific inhibitor with Ki values of 2.8 and 0.4 nM for MMP-2 and MMP-9, respectively. The Gly mutant has a Ki of 2.1 nM for MMP-9 and > 40 uM for MMP-2, indicating that engineered TIMPs can discriminate between MMPs in the same subfamily. In collaboration with Dr. Yingnan Zhang at Genentech, we have developed a protocol for the phage display of full-length human TIMP-2 to identify high-affinity selective inhibitors of human MMP-1, a protease that plays a role in cleaving extracellular matrix (ECM) components, connective tissue remodeling during development, angiogenesis, and apoptosis. We have generated a library containing 2x1010 variants of TIMP-2 randomized at residues 2-6 (L1), at residues 34-40 (L2) and 67-70 (L3)., The L1 library yielded a positive signal for MMP-1 binding. Clones from the L1 library, designated TM1, TM8, TM13, and TM14, were isolated after 5 rounds of selection on immobilized MMP-1 and MMP-3 and found to show a greater selectivity for MMP-1 relative to MMP-3. TM8, which has Ser2 to Asp and Ser4 to Ala substitutions, showed the greatest apparent selectivity of 10-fold toward MMP-1 compared to MMP-3. The various mutations identified by phage display were introduced into recombinant Nterminal TIMP-2 and the variants characterized as inhibitors of an array of MMP catalytic domains. The TM8-based mutant showed pronounced selectivity (> 1000-fold for MMP-1 vs. MMP-3) and may be a step towards the generation of MMP-1-specific inhibitors. Molecular modeling was used to rationalize the structural basis of MMP selectivity in the mutants.
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Date Issued
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2009
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PURL
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http://purl.flvc.org/FAU/221942
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Subject Headings
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Metalloproteinases, Inhibitors, Apoptosis, Extracellular matrix proteins, Proteolytic enzymes
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Format
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Document (PDF)
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Title
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FAU Climate Change Initiative Priority Theme: Research, Engineering, and Adaption to a Change Climate.
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Creator
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Berry, Leonard, Koch, Marguerite, Center for Environmental Studies, Benscoter, Brian, Comas, Xavier, Devlin, Donna, Fadiman, Maria, Gerstein, E., Herzing, Denise L., Hindle, Tobin, Milton, Sarah L., Oleinik, Anton E., Proffitt, C. Edward, Restrepo, Jorge I., Root, Tara L., Wyneken, Jeanette, Xie, Zhixiao, Zhang, Xing-Hai, Esnard, Ann-Margaret, Mitsova, Diana, Murley, J., Vos, J., Escaleras, Monica, Mehallis, M., Shaw, Eric H., Hardman, Guillermo [John], Lambert, Julie, Thomas, G., Arockiasamy, Madasamy, Bloetscher, Frederick, Carvalho, G., Dhanak, Manhar R., Frisk, George V., Kaisar, Evangelos I., Kalva, Hari, Meeroff, Daniel E., Rodriguez, Jarice, Scarlatos, Panagiotis (Pete) D., Shankar, Ravi, Teegavarapu, Ramesh, Brown, Clifford T., McAfee, Francis, Widener, Patricia, Dalgleish, Fraser R., Hanisak, M. Dennis, McMulloch, S., O'Corry-Crowe, Gregory, Pomponi, Shirley A., Reed, John K., Scarpa, John, Voss, Joshua, Heimlich, Barry N., Alvarez, R., Jolley, J., Edwards, A., Charles E. Schmidt College of Science, Harbor Branch Oceanographic Institute, College of Business, Dorothy F. Schmidt College of Arts and Letters, College of Education, College of Engineering and Computer Science
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Date Issued
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2010
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PURL
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http://purl.flvc.org/fau/fd/FA00003457
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Format
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Citation
Pages