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(1 - 8 of 8)
- Title
- RAMAN SPECTRUM STUDY OF PHASE I AND II OF SOLID AMMONIA (GRANEISEN PARAMETERS).
- Creator
- LUO, RENKANG, Florida Atlantic University
- Abstract/Description
-
The Raman spectra of ammonia solid I and II were studied in the lattice and intramolecular region. The study of the internal modes of phase I suggests the presence of disorder in the ordered phase. The lattice modes of phase II are, for the first time, carefully reported as two very broad lines superimposed on an overdamped feature. The results confirm the structure previously determined by neutron scattering and NMR that phase II is a typical disordered phase with space group P6,3/mmc. A...
Show moreThe Raman spectra of ammonia solid I and II were studied in the lattice and intramolecular region. The study of the internal modes of phase I suggests the presence of disorder in the ordered phase. The lattice modes of phase II are, for the first time, carefully reported as two very broad lines superimposed on an overdamped feature. The results confirm the structure previously determined by neutron scattering and NMR that phase II is a typical disordered phase with space group P6,3/mmc. A mode assignment was tentatively made and Gruneisen parameters of the two assumed translational modes calculated. In terms of the Michel-Naudts theory of rotational-translational interactions, phase II is in the slow relaxation regime. A four-band model was used for the intramolecular stretching region.
Show less - Date Issued
- 1986
- PURL
- http://purl.flvc.org/fcla/dt/14346
- Subject Headings
- Ammonia--Spectra, Raman spectroscopy
- Format
- Document (PDF)
- Title
- Raman spectroscopic study of yttrium barium(2)(copper(1-x)iron(x))oxygen(7+delta).
- Creator
- Tanabe, Makoto., Florida Atlantic University, Liu, Da Wei
- Abstract/Description
-
Polycrystalline bulk samples with the chemical formula YBa2(Cu1-xFex)3O7+delta were fabricated by the standard solid-state reaction method, and studied through magnetic susceptibility and Raman scattering experiments. In the Raman experiments, the Cu(1)-O(1) c-axial Ag stretching mode at ~502cm^-1 was investigated extensively at temperatures ranging from 23K to 773K. The room-temperature Raman spectra indicated a trend for saturation in frequency shift (as a function of iron concentration)....
Show morePolycrystalline bulk samples with the chemical formula YBa2(Cu1-xFex)3O7+delta were fabricated by the standard solid-state reaction method, and studied through magnetic susceptibility and Raman scattering experiments. In the Raman experiments, the Cu(1)-O(1) c-axial Ag stretching mode at ~502cm^-1 was investigated extensively at temperatures ranging from 23K to 773K. The room-temperature Raman spectra indicated a trend for saturation in frequency shift (as a function of iron concentration). This was interpreted as evidence supporting the occurrence of a type of iron clustering in the (001) basal plane. Effects of such a cluster formation upon the mechanism of superconductivity were considered. The low temperature Raman spectra show that the 502cm^-1 mode frequency increased slightly with decreasing temperature for all of the studied values of iron concentration without exhibiting any anomalous behavior. In the high temperature Raman spectra, a significant softening of the 502cm^-1 mode, indicative of a phase transition onset, was observed.
Show less - Date Issued
- 1990
- PURL
- http://purl.flvc.org/fcla/dt/14597
- Subject Headings
- Raman spectroscopy, Copper oxide superconductors
- Format
- Document (PDF)
- Title
- Raman spectroscopic studies of stabilized zirconia at elevated temperatures.
- Creator
- Lacher, Nathan, Florida Atlantic University, Liu, David, Charles E. Schmidt College of Science, Department of Physics
- Abstract/Description
-
Raman spectroscopy was used to determine the phase structure and phase stability of zirconia mixtures for various elevated temperatures, type and concentration of oxides added to zirconia, and fabrication process. All 8 wt.% yttria samples showed mostly the tetragonal structure at room temperature. Three of the four 8 wt.% yttria samples exhibited the tetragonal structure at elevated temperatures, while no conclusion was inferred for the powdered sample. As compared with yttria, ceria is a...
Show moreRaman spectroscopy was used to determine the phase structure and phase stability of zirconia mixtures for various elevated temperatures, type and concentration of oxides added to zirconia, and fabrication process. All 8 wt.% yttria samples showed mostly the tetragonal structure at room temperature. Three of the four 8 wt.% yttria samples exhibited the tetragonal structure at elevated temperatures, while no conclusion was inferred for the powdered sample. As compared with yttria, ceria is a less effective stabilizer with respect to the zirconia tetragonal structure. A monoclinic transformation between 400 K and 800 K was observed in the 4 wt.% yttria sample which had been processed by rapid quenching. Adding alumina to 4 wt.% yttria did not completely stabilize the tetragonal structure at or above room temperature, making it a less effective stabilizer than yttria or ceria. The phase transformation was responsible for the unusual values in the Gr uneisen parameters obtained for the 4 wt.% yttria sample.
Show less - Date Issued
- 1990
- PURL
- http://purl.flvc.org/fcla/dt/14589
- Subject Headings
- Zirconium oxide--Spectra, Raman spectroscopy
- Format
- Document (PDF)
- Title
- Study of cell penetrating peptides with Raman spectroscopy and microscopy.
- Creator
- Ye, Jing., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
Cell penetrating peptides (CPPs) have drawn the attention of researchers due to their ability to internalize large cargos into cells including cancer cells. The mechanism(s) with which the peptides enter the cell, however, is/are not clear and full of controversy. The peptide conformations and their microenvironment in live cells had been unknown until the development of a technique developed in our lab. As a first demonstration of principle, penetratin, a 16-residue CPP derived from the...
Show moreCell penetrating peptides (CPPs) have drawn the attention of researchers due to their ability to internalize large cargos into cells including cancer cells. The mechanism(s) with which the peptides enter the cell, however, is/are not clear and full of controversy. The peptide conformations and their microenvironment in live cells had been unknown until the development of a technique developed in our lab. As a first demonstration of principle, penetratin, a 16-residue CPP derived from the Antennapedia homeodomain protein of Drosophila, was measured in single, living melanoma cells. Carbon-13 labeling of the Phe residue of penetratin was used to shift the intense aromatic ring-breathing vibrational mode from 1003 to 967 cm-1, thereby enabling the peptide to be traced in cells. Difference spectroscopy and principal components analysis (PCA) were used independently to resolve the Raman spectrum of the peptide from the background cellular Raman signals., On the basis of the position of the amide I vibrational band in the Raman spectra, the secondary structure of the peptide was found to be mainly random coil and b-strand in the cytoplasm, and possibly assembling as b-sheets in the nucleus. Next, label-free transportan was studied with the same methodology. The peptide, besides predominantly a-helix, adopted a significant portion of b-sheet conformation in the cytoplasm and nucleolus, which is different from the peptide in aqueous solution. The peptide microenvironment was also probed through H-bonding reported by the tyrosine Fermi doublet. Transportan displayed a tendency to accumulate in the cytoplasm over time which was unlike penetratin, which concentrated in the nucleus. The relative concentration of CPPs in various locations of live melanoma cells was directly estimated from the Raman spectra using average Phe concentration in the cell as an internal standard., The rapid entry and almost uniform cellular distribution of both peptides, as well as the lack of correlation between peptide and lipid Raman signatures, indicated that the mechanism of CPP internalization under the conditions of study was probably non-endocytotic. Last, transportan and penetratin were studied using polarized Raman spectroscopy for more detailed vibrational spectroscopic information of the two peptides in water and TFE solutions. The majority of the bands in the Raman spectra of the peptides were highly polarized, consistent with the high symmetry of aromatic ring side chain vibrational bands dispersed throughout the spectra. This work has provided new insights into the structure of CPPs in live cells and in solutions.
Show less - Date Issued
- 2011
- PURL
- http://purl.flvc.org/FAU/3342344
- Subject Headings
- Peptides, Analysis, Infrared spectroscopy, Raman spectroscopy, Cellular signal transduction
- Format
- Document (PDF)
- Title
- Implementation of Raman Spectroscopy into First Year Undergraduate Chemistry Curriculum.
- Creator
- Hyvarinen, Satu, Rezler, Evonne, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
Raman spectroscopy based activities were developed and implemented into the first year chemistry undergraduate curriculum. The implementation of these experiences and experiments and the utility of Raman spectroscopy as a teaching tool to convey anchoring chemistry concepts using a hands-on Raman spectroscopy based approach are discussed. Fundamental principles of chemistry, such as the interaction of light with matter, molecular bonding, equilibrium, and acid base reactions are facilitated...
Show moreRaman spectroscopy based activities were developed and implemented into the first year chemistry undergraduate curriculum. The implementation of these experiences and experiments and the utility of Raman spectroscopy as a teaching tool to convey anchoring chemistry concepts using a hands-on Raman spectroscopy based approach are discussed. Fundamental principles of chemistry, such as the interaction of light with matter, molecular bonding, equilibrium, and acid base reactions are facilitated through use of these Raman spectroscopy based experiments and experiences. An assessment of student learning gains as a result of participation in a Raman spectroscopy experience was also conducted and is discussed.
Show less - Date Issued
- 2018
- PURL
- http://purl.flvc.org/fau/fd/FA00013017
- Subject Headings
- Raman spectroscopy, Undergraduate chemistry, Chemistry--Study and teaching
- Format
- Document (PDF)
- Title
- TEMPERATURE AND VOLUME DEPENDENCE OF LATTICE VIBRATIONAL FREQUENCIES FOR SOLID AMMONIA I.
- Creator
- NYE, CHARLES LEE., Florida Atlantic University
- Abstract/Description
-
The frequencies of three lattice vibrational nodes of solid ammonia I were measured as functions of temperature and molar volume, via Raman spectroscopy. Calculated Gruneisen parameters of 2.6, 2.4, and 0.8, for modes with frequencies near 108 cm^-1 , 140 cm^-1 and 306 cm^-1 , respectively, identify the first two modes to be translational and the third librational in accordance with previous assignments. The Gruneisen parameter of the libration is lower than expected for purely octopolar...
Show moreThe frequencies of three lattice vibrational nodes of solid ammonia I were measured as functions of temperature and molar volume, via Raman spectroscopy. Calculated Gruneisen parameters of 2.6, 2.4, and 0.8, for modes with frequencies near 108 cm^-1 , 140 cm^-1 and 306 cm^-1 , respectively, identify the first two modes to be translational and the third librational in accordance with previous assignments. The Gruneisen parameter of the libration is lower than expected for purely octopolar electrostatic interactions between molecules. The change in frequency with temperature of all three modes is due to their interaction with the mode near 108 cm^-1. The lifetimes of both translations are determined by their rate of combination with librations near 306 cm^-1 and 313 cm^-1. The lifetime of the libration near 306 cm^-1 depends on its rate of combination with the two translations (108 cm^-1 and 140 cm^-1) and a libration near 440 cm^-1.
Show less - Date Issued
- 1985
- PURL
- http://purl.flvc.org/fcla/dt/14251
- Subject Headings
- Ammonia--Analysis, Ammonia--Spectra, Lattice dynamics, Raman spectroscopy
- Format
- Document (PDF)
- Title
- Raman and surface-enhanced raman spectroscopy of G-quadruplexes.
- Creator
- Friedman, Samantha, Terentis, Andrew C., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
G-quadruplexes (G4s) are nucleic acid structures formed from π-stacked planar sets of four Hoogsteen hydrogen bonded guanine bases. G4s emerged as potential therapeutic targets based on their ability to modulate gene expression and inhibit the ability of telomerase to elongate chromosomal telomeres. Raman spectroscopy, polarized Raman spectroscopy, surface-enhanced Raman spectroscopy (SERS), and other optical spectroscopic techniques were used to characterize the G4s formed by four different...
Show moreG-quadruplexes (G4s) are nucleic acid structures formed from π-stacked planar sets of four Hoogsteen hydrogen bonded guanine bases. G4s emerged as potential therapeutic targets based on their ability to modulate gene expression and inhibit the ability of telomerase to elongate chromosomal telomeres. Raman spectroscopy, polarized Raman spectroscopy, surface-enhanced Raman spectroscopy (SERS), and other optical spectroscopic techniques were used to characterize the G4s formed by four different DNA sequences: human telomeric (HT), thrombin-binding aptamer (TBA), nuclease hypersensitive element III1 region of the c- Myc gene promoter (Myc), and a single loop-isomer of Myc (MycL1).
Show less - Date Issued
- 2015
- PURL
- http://purl.flvc.org/fau/fd/FA00004370, http://purl.flvc.org/fau/fd/FA00004370
- Subject Headings
- Nucleic acids, Binding sites (Biochemistry), Biochemical genetics, Raman spectroscopy, Raman effect, Surface enhanced, Spectroscopic imaging, Spectrum analysis
- Format
- Document (PDF)
- Title
- Study of Cell Penetrating Peptide Uptake and Cancer Cell Discrimination with Raman Spectroscopy and Microscopy.
- Creator
- Cosme, Patrick Jason, Terentis, Andrew C., Florida Atlantic University, Charles E Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
Cell penetrating peptides (CPPs) are short sequences of amino acids that excel in crossing the cellular membrane without inducing cytotoxicity Interest in these peptides stem from their ability to be attached, and grant their penetrating properties to, a variety of cargo In this work we have combined the application of Confocal Raman Microscopy (CRM) and Atomic Force Microscopy for the first time to examine the interactions of unlabeled Transportan (TP), one of the most well studied CPPs,...
Show moreCell penetrating peptides (CPPs) are short sequences of amino acids that excel in crossing the cellular membrane without inducing cytotoxicity Interest in these peptides stem from their ability to be attached, and grant their penetrating properties to, a variety of cargo In this work we have combined the application of Confocal Raman Microscopy (CRM) and Atomic Force Microscopy for the first time to examine the interactions of unlabeled Transportan (TP), one of the most well studied CPPs, with mammalian cells CRM’s capability to discriminate control and treated cell groups was verified by principal component analysis (PCA) and linear discriminant analysis (LDA) and was 93-100% accurate We’ve determined that at a concentration of 20 μM TP enters cells through a non-endocytotic mechanism, has a high affinity for the cytoplasm and membranes, and results in a significant increase in cellular stiffness Our work provides the first direct evidence of this cell-stiffening phenomenon SFTI-1, the smallest member of a bicyclic, cysteine rich class of CPPs, was examined by CRM to determine the potential role of cyclic structure on cellular uptake The peptide, along with monocyclic and linear analogs was heavy isotope labeled and incubated with mammalian cells at numerous concentrations and timespans Our work is the first SFTI-1 uptake study forgoing the use of fluorophore conjugates, which have been linked to artificial cellular uptake We demonstrate herein the absence of any CRM detectable uptake, providing the first evidence that SFTI-1 may not be a CPP Finally, CRM was applied to the discrimination of normal and basal cell carcinoma cells obtained from the same donor The use of patient matched cells avoids the normal biochemical variations that exist among individuals, ensuring that discrimination is based solely on the cell’s diseased state CRM spectra, analyzed by PCA and LDA, were capable of spectral discrimination with 100% accuracy Major differences in the cancerous cells were an increase in lipids and nucleic acids, and an overall decrease in protein We also demonstrate an enhancement in Raman signal through the use of an aluminum foil substrate, providing a practical approach for measuring cells with thin morphologies
Show less - Date Issued
- 2016
- PURL
- http://purl.flvc.org/fau/fd/FA00004756
- Subject Headings
- Peptides--Analysis, Peptides--Therapeutic use, Peptides--Physiological transport, Cellular signal transduction, Raman spectroscopy, Infrared spectroscopy
- Format
- Document (PDF)
