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Articles 1 - 7 of 7
Full-Text Articles in Physical Sciences and Mathematics
Photosynthetic Response Of Soybean To Twospotted Spider Mite (Acari: Tetranychydae) Injury, Adeney De Freitas Bueno, Regiane Cristina Oliveira De Freitas Bueno, Paul David Nabity, Leon George Higley, Odair Aparecido Fernandes
Photosynthetic Response Of Soybean To Twospotted Spider Mite (Acari: Tetranychydae) Injury, Adeney De Freitas Bueno, Regiane Cristina Oliveira De Freitas Bueno, Paul David Nabity, Leon George Higley, Odair Aparecido Fernandes
School of Natural Resources: Faculty Publications
The twospotted spider mite Tetranychus urticae Koch is a common pest on soybean plants. To clarify plantarthropod interaction on mite-soybean system, leaf fluorescence, photosynthetic responses to variable carbon dioxide levels, and chlorophyll content were evaluated. Significant photosynthetic rate reduction was observed due to stomatal limitation. Stomatal closure was the major plant physiological response. As a consequence, there was reduction in photosynthetic rates. Surprisingly, plants did not show chlorophyll content reduction associated with photosynthetic impairment. No differences in fluorescence data indicate that T. urticae injury did not impair the function of light harvesting and photoelectron transport. These results showed that T. …
Studies Of Surfactants Effect On Riboflavin Fluorescence And Its Determination In Commercial Food Products And Vitamin Tablets., William Emmanuel Ghann
Studies Of Surfactants Effect On Riboflavin Fluorescence And Its Determination In Commercial Food Products And Vitamin Tablets., William Emmanuel Ghann
Electronic Theses and Dissertations
A simple and economical fluorometer using blue LEDs excitation sources and simple PMT detection had been built, assembled, optimized, and employed for measurement of fluorescence from riboflavin (vitamin B2). Surfactants have been known to enhance the intensity of fluorescence of fluorescent compounds. Fluorescence analysis of riboflavin in the presence of various anionic, cationic, and nonionic surfactants was also conducted to determine if they could improve analysis. However, the surfactants employed did not seem to have any meaningful enhancement; in fact, some actually diminished the fluorescence intensity of riboflavin. The procedure was linear for riboflavin from 0.01 to 2.5 …
Recombination Fluorescence In Ultracold Neutral Plasmas, Scott D. Bergeson, F. Robicheaux
Recombination Fluorescence In Ultracold Neutral Plasmas, Scott D. Bergeson, F. Robicheaux
Faculty Publications
We present the first measurements and simulations of recombination fluorescence from ultracold neutral calcium plasmas. This method probes three-body recombination at times less than 1 µs, shorter than previously published time scales. For the lowest initial electron temperatures, the recombination rate scales with the density as n22, significantly slower than the predicted n3. Recombination fluorescence opens a new diagnostic window in ultracold plasmas. In most cases it probes deeply bound level populations that depend critically on electron energetics. However, a perturbation in the calcium 4snd Rydberg series allows our fluorescence measurements to probe the population in weakly bound levels that …
Fluorescence Characteristics Of Triazine-Manufacturing Wastewater, Lin Huang, Shuyan Qiu, Neissa Pinzon, Li-Ta Lien, Lu-Kwang Ju
Fluorescence Characteristics Of Triazine-Manufacturing Wastewater, Lin Huang, Shuyan Qiu, Neissa Pinzon, Li-Ta Lien, Lu-Kwang Ju
Chemical, Biomolecular, and Corrosion Engineering Faculty Research
Samples taken at different points in the wastewater treatment process of a triazine-manufacturing plant were scanned by fluorescence spectroscopy, in the wavelength range of 200-900 nm. Reproducibly, the fluorescence spectra revealed one single major peak at excitation and emission wavelengths of 258 and 370 nm respectively. Aqueous solutions of purified active compounds, including Atrazine, Propazine, Simazine, Terbuthylazine, Metolachlor, and Benoxacor, were also scanned. No significant fluorescence was observed in these standard solutions at concentrations up to 100 mg/L. Selected plant samples as well as standard solutions of Atrazine, Metolachlor, and toluene were further analyzed using high-performance liquid chromatography with absorbance …
Determination Of Enantiomeric Compositions Of Analytes Using Novel Fluorescent Chiral Molecular Micelles And Steady State Fluorescence Measurements, Alicia A. Williams, Sayo O. Fakayode, Onur Alptürk, Christina M. Jones, Mark Lowry, Robert M. Strongin, Isiah M. Warner
Determination Of Enantiomeric Compositions Of Analytes Using Novel Fluorescent Chiral Molecular Micelles And Steady State Fluorescence Measurements, Alicia A. Williams, Sayo O. Fakayode, Onur Alptürk, Christina M. Jones, Mark Lowry, Robert M. Strongin, Isiah M. Warner
Chemistry Faculty Publications and Presentations
Novel fluorescent chiral molecular micelles (FCMMs) were synthesized, characterized, and employed as chiral selectors for enantiomeric recognition of non-fluorescent chiral molecules using steady state fluorescence spectroscopy. The sensitivity of the fluorescence technique allowed for investigation of low concentrations of chiral selector (3.0 x 10(-5) M) and analyte (5.0 x 10(-6) M) to be used in these studies. The chiral interactions of glucose, tartaric acid, and serine in the presence of FCMMs poly(sodium N-undecanoyl-L-tryptophanate) [poly-L-SUW], poly(sodium N-undecanoyl-L-tyrosinate) [poly-L-SUY], and poly(sodium N-undecanoyl-L-phenylalininate) [poly-SUF] were based on diastereomeric complex formation. Poly-L-SUW had a significant fluorescence emission spectral difference as compared to poly-L-SUY and …
Mutational Analysis Of The Stability Of The H2a And H2b Histone Monomers, Matthew R. Stump, Lisa M. Gloss
Mutational Analysis Of The Stability Of The H2a And H2b Histone Monomers, Matthew R. Stump, Lisa M. Gloss
Faculty Publications - Department of Biological & Molecular Science
The eukaryotic histone heterodimer H2A–H2B folds through an obligatory dimeric intermediate that forms in a nearly diffusion-limited association reaction in the stopped-flow dead time. It is unclear whether there is partial folding of the isolated monomers before association. To address the possible contributions of structure in the monomers to the rapid association, we characterized H2A and H2B monomers in the absence of their heterodimeric partner. By far-UV circular dichroism, the H2A and H2B monomers are 15% and 31% helical, respectively—significantly less than observed in X-ray crystal structures. Acrylamide quenching of the intrinsic Tyr fluorescence was indicative of tertiary structure. The …
Fluorescence Intensity And Lifetime Imaging Of Free And Micellar-Encapsulated Doxorubicin In Living Cells, X Dai, Zhilian Yue, M E Eccleston, J Swartling, N K H Slater, C F Kaminski
Fluorescence Intensity And Lifetime Imaging Of Free And Micellar-Encapsulated Doxorubicin In Living Cells, X Dai, Zhilian Yue, M E Eccleston, J Swartling, N K H Slater, C F Kaminski
Faculty of Science - Papers (Archive)
Frequency domain fluorescence lifetime imaging microscopy (FLIM) has been used in combination with laser scanning confocal microscopy to study the cellular uptake behavior of the antitumor drug doxorubicin (DOX) and micellar-encapsulated DOX (PLyAd-DOX). The endocytosis uptake process of PLyAd-DOX was monitored over 72 hours using confocal microscopy, with a maximum fluorescence recorded at incubation periods around 24 hours. The micellar structure was not found to release the encapsulated DOX during the time course of imaging. FLIM revealed single lifetime distributions of PLyAd-DOX during accumulation in the cytoplasm. The free DOX in contrast was observed both in the cytoplasm and the …