Current Search: fluorescence lifetime (x)
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- Title
- Fluorescence Lifetime Imaging and Spectroscopy Aided Tracking of ZnO and CdS:Mn/ZnS/ N-acetyl cysteine (NAC) Quantum Dots in Citrus Plants.
- Creator
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Washington, Torus, Gesquiere, Andre, Rajaraman, Swaminathan, Zhai, Lei, University of Central Florida
- Abstract / Description
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In this thesis, we present an efficacious way of tracking nanoparticle movement in plant tissue through the use of fluorescence lifetime imaging (FLIM) and spectroscopy as well as a review of nanoparticle uptake in plants and the proposed mechanisms governing them. Given the increasing number of nanomaterials in agriculture and society as a whole, proper imaging tools and proactive measures must be taken to track nanoparticle movement in plant tissues and create infrastructure and products to...
Show moreIn this thesis, we present an efficacious way of tracking nanoparticle movement in plant tissue through the use of fluorescence lifetime imaging (FLIM) and spectroscopy as well as a review of nanoparticle uptake in plants and the proposed mechanisms governing them. Given the increasing number of nanomaterials in agriculture and society as a whole, proper imaging tools and proactive measures must be taken to track nanoparticle movement in plant tissues and create infrastructure and products to keep things sustainable and safe. Herein we report a ZnO comparable nanoparticle(-) a CdS:Mn/ZnS/ N-acetyl cysteine (NAC) quantum dot(-) which boasts longer lifetimes and suitable fluorescent properties above ZnO to properly delineate from plant tissue fluorescence of chlorophyll and cinnamic acids. In addition to FLIM mapping, quantum dot localization in plant vascular tissue was clearly seen and confirmed via characteristic emission spectra and time correlated single photon counting decay curves (TCSPC). Most quantum dots were seen to reside in the xylem. Plant age and structure was seen to affect uptake. QD size likely restricted extensive translocation. Inhibitive effects of QDs were likely water and mechanical stress. We surmise that travel of the cadmium quantum dots up the leaf and branch plant tissues is likely most governed by diffusion as the quantum dots bound to the cell structures create a diffusion gradient which aids travel up the leaf.
Show less - Date Issued
- 2017
- Identifier
- CFE0006820, ucf:51772
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006820
- Title
- OPTICAL AND PHYSICAL PROPERTIES OF CERAMIC CRYSTAL LASER MATERIALS.
- Creator
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Simmons, Jed, Bass, Michael, University of Central Florida
- Abstract / Description
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Historically ceramic crystal laser material has had disadvantages compared to single crystal laser material. However, progress has been made in the last decade and a half to overcome the disadvantages associated with ceramic crystal. Today, because of the promise of ceramic crystal as a high power laser material, investigation into its properties, both physical and optical, is warranted and important. Thermal expansion was measured in this thesis for Nd:YAG (yttrium aluminum garnet) ceramic...
Show moreHistorically ceramic crystal laser material has had disadvantages compared to single crystal laser material. However, progress has been made in the last decade and a half to overcome the disadvantages associated with ceramic crystal. Today, because of the promise of ceramic crystal as a high power laser material, investigation into its properties, both physical and optical, is warranted and important. Thermal expansion was measured in this thesis for Nd:YAG (yttrium aluminum garnet) ceramic crystal using an interferometric method. The interferometer employed a spatially filtered HeNe at 633 nm wavelength. Thermal expansion coefficients measured for the ceramic crystal samples were near the reported values for single crystal Nd:YAG. With a similar experimental setup as that for the thermal expansion measurements, dn/dT for ceramic crystal Nd:YAG was measured and found to be slightly higher than the reported value for single crystal. Depolarization loss due to thermal gradient induced stresses can limit laser performance. As a result this phenomenon was modeled for ceramic crystal materials and compared to single crystals for slab and rod shaped gain media. This was accomplished using COMSOL Multiphysics, and MATLAB. Results indicate a dependence of the depolarization loss on the grain size where the loss decreases with decreased grain size even to the point where lower loss may be expected in ceramic crystals than in single crystal samples when the grain sizes in the ceramic crystal are sufficiently small. Deformation-induced thermal lensing was modeled for a single crystal slab and its relevance to ceramic crystal is discussed. Data indicates the most notable cause of deformation-induced thermal lensing is a consequence of the deformation of the top and bottom surfaces. Also, the strength of the lensing along the thickness is greater than the width and greater than that due to other causes of lensing along the thickness of the slab. Emission spectra, absorption spectra, and fluorescence lifetime were measured for Nd:YAG ceramic crystal and Yb:Lu2O3 ceramic crystal. No apparent inhomogeneous broadening appears to exist in the Nd:YAG ceramic at low concentrations. Concentration and temperature dependence effects on emission spectra were measured and are presented. Laser action in a thin disk of Yb:Y2O3 ceramic crystal was achieved. Pumping was accomplished with a fiber coupled diode laser stack at 938 nm. A slope efficiency of 34% was achieved with maximum output energy of 28.8 mJ/pulse.
Show less - Date Issued
- 2007
- Identifier
- CFE0001764, ucf:47273
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001764
- Title
- DEVELOPMENT OF LUMINESCENT RUTHENIUM COMPLEXES FOR IN-VITRO FLUORESCENCE IMAGING OF ANGIOGENESIS WITH THE RGD PEPTIDE.
- Creator
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Victoria, Rosmery, Hinkle, Charles R., University of Central Florida
- Abstract / Description
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Herein we report the synthesis of an RGD-ruthenium bipyridine 2+ complex aimed at the detection of angiogenesis. Angiogenesis plays a critical role in many pathophysiological processes, such as tumor growth. The alpha v-integrins (alpha v beta 3, alpha v beta 5) are currently used as molecular targeting sites for anti-angiogenic therapies. The 2+ complex is an organometallic luminescent probe, which enables noninvasive, in vitro imaging of alpha v beta 3 expression. Peptides containing the...
Show moreHerein we report the synthesis of an RGD-ruthenium bipyridine 2+ complex aimed at the detection of angiogenesis. Angiogenesis plays a critical role in many pathophysiological processes, such as tumor growth. The alpha v-integrins (alpha v beta 3, alpha v beta 5) are currently used as molecular targeting sites for anti-angiogenic therapies. The 2+ complex is an organometallic luminescent probe, which enables noninvasive, in vitro imaging of alpha v beta 3 expression. Peptides containing the arginine-glycine-aspartic acid (RGD) sequence have been shown to bind strongly to the alpha v beta 3 integrin. The RuBpy probes are soluble in water, display long lifetimes, and are photochemically stable. These properties enable the Ru(tris-bpy) complexes to be useful in numerous applications in biophysical and cell biology. The 2+ complex was synthesized by combining the succinimidyl ester on the RuBpy complex with the lysine of the c(RGDfK) peptide. The results of the one-photon fluorescence bioimaging showed selective binding of the cyclic RGD to alpha v beta 3 integrin, which supports previous literature. The high luminescence intensity, long lifetimes, and low cell toxicity levels of dye 2+, illustrates the potential usage of this probe for future biological applications.
Show less - Date Issued
- 2012
- Identifier
- CFH0004234, ucf:44898
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH0004234