18 results on '"Ohta, N."'
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2. Application of Nanosecond Pulsed Electric Field and Autofluorescence Lifetime Microscopy of FAD in Lung Cells.
- Author
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Awasthi K, Wu TE, Hsu HY, and Ohta N
- Subjects
- Cell Membrane metabolism, Lung, Microscopy, Apoptosis
- Abstract
Exposure of nanosecond pulsed electric fields (nsPEFs) to live cells is an increasing research interest in biology and medicine. Despite extensive studies, a question still remains as to how effects of application of nsPEF on intracellular functions are different between cancerous cells and normal cells and how the difference can be detected. Herein, we have presented an approach of autofluorescence lifetime (AFL) microscopy of flavin adenine dinucleotide (FAD) to detect effects of application of nsPEF having 50 ns of a pulse width, nsPEF(50), on intracellular function in lung cancerous cells, A549 and H661, which show nsPEF(50)-induced apoptosis, and normal cells, MRC-5, in which the field effect is less or not induced. Then, the application of nsPEF(50) is shown to increase the lifetime of FAD autofluorescence in lung cancerous cells, whereas the electric field effects on the autofluorescence of FAD was not significant in normal healthy cells, which indicates that the lifetime measurements of FAD autofluorescence are applicable to detect the field-induced change in intracellular functions. Lifetime and intensity microscopic images of FAD autofluorescence in these lung cells were also acquired after exposure to the apoptosis-inducer staurosporine (STS). Then, it was found that the AFL of FAD became longer after exposure not only in the cancerous cells but also in the normal cells. These results indicate that nsPEF(50) applied to lung cells induced apoptotic cell death only in lung cancerous cells (H661 and A549) but not in lung normal cells (MRC-5), whereas STS induced apoptotic cell death both in lung cancerous cells and in lung normal cells. The lifetime microscopy of FAD autofluorescence is suggested to be very useful as a sensitive detection method of nsPEF-induced apoptotic cell death.
- Published
- 2023
- Full Text
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3. Structure of Ultrafine Bubbles and Their Effects on Protein and Lipid Membrane Structures Studied by Small- and Wide-Angle X-ray Scattering.
- Author
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Hirai M, Ajito S, Takahashi K, Iwasa T, Li X, Wen D, Kawai-Hirai R, Ohta N, Igarashi N, and Shimizu N
- Subjects
- Liposomes chemistry, Liposomes metabolism, Cell Membrane chemistry, Membrane Proteins chemistry, Membrane Proteins metabolism, Scattering, Small Angle, X-Ray Diffraction
- Abstract
Ultrafine bubbles (UFBs) are defined as small gas-filled bubbles with a diameter smaller than 1 μm. UFBs are stable for several weeks in aqueous solutions due to their small size. Although the mechanism of the stability of UFBs remains under intensive investigation, industrial applications of UFBs have recently arisen in various fields such as agricultural and fishery industries and medical therapy. The relevance of ions (protons and hydroxide anions) in UFB solutions has been discussed; however, the mechanism underlying the behavior of UFBs is still ambiguous and there is little direct evidence of the effect of UFBs on biological materials. This study deals with gaseous UFBs in aqueous solutions. Using small- and wide-angle X-ray scattering, we have investigated the structures of UFBs (air-UFBs, O
2 -UFBs, and N2 -UFBs) and their effect on protein and lipid membrane structures. X-ray scattering and modeling data suggest that UFBs present a dynamic diffusive boundary (interface) due to the continuous release and absorption of gas. UFBs were found to not affect the structures of proteins at all hierarchal structure levels (from quaternary to tertiary, to internal, to secondary), whereas they did influence the packing and fluctuation of the hydrocarbon chains in the liposomes but not their shapes.- Published
- 2019
- Full Text
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4. Restoration of Myoglobin Native Fold from Its Initial State of Amyloid Formation by Trehalose.
- Author
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Hirai M, Ajito S, Iwase H, Takata SI, Ohta N, Igarashi N, and Shimizu N
- Subjects
- Amyloid chemistry, Hydrogen-Ion Concentration, Protein Denaturation, Protein Folding, Temperature, Amyloid chemical synthesis, Myoglobin chemistry, Trehalose chemistry
- Abstract
Organisms having tolerances against extreme environments produce and accumulate stress proteins and/or sugars in cells against the extreme environment such as high or low temperature, drying, and so forth. Sugars and/or polyols are known to prevent protein denaturation and enzyme deactivation. In particular, trehalose has received considerable attention because of its association with cryptobiosis and anhydrobiosis. This study focuses on the restoration of acid-denatured amyloid transition of myoglobin by trehalose. Myoglobin is known to proceed amyloidogenic reaction under denaturation conditions. We found that acid-denatured myoglobin at an initial process of amyloidogenic reaction (helix-to-sheet transition followed by oligomerization) at 25 °C was substantially restored to its native structure by trehalose. This action was prominent during the early stage of amyloid formation. Recent results showed that sugars are preferentially excluded from the protein surface to preserve its hydration shell and stabilize the protein structure against chemical and thermal denaturation. Therefore, the present results suggest that trehalose will restore the tightly bound water molecules around the hotspot (G-helix) of myoglobin on the amyloid transition by its intrinsic preservative action of the native hydration shell against denaturation. The present finding on the restorative action by trehalose could provide new insights into protein folding and amyloidosis.
- Published
- 2018
- Full Text
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5. Preferential Intercalation of Human Amyloid-β Peptide into Interbilayer Region of Lipid-Raft Membrane in Macromolecular Crowding Environment.
- Author
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Hirai M, Ajito S, Sato S, Ohta N, Igarashi N, and Shimizu N
- Subjects
- 1,2-Dipalmitoylphosphatidylcholine chemistry, 1,2-Dipalmitoylphosphatidylcholine metabolism, Amyloid beta-Peptides chemistry, Cholesterol chemistry, Cholesterol metabolism, Gangliosides chemistry, Gangliosides metabolism, Humans, Lipid Bilayers chemistry, Membrane Microdomains, Peptide Fragments chemistry, Protein Binding, Protein Multimerization, Unilamellar Liposomes chemistry, Amyloid beta-Peptides metabolism, Lipid Bilayers metabolism, Peptide Fragments metabolism, Unilamellar Liposomes metabolism
- Abstract
This study focuses on the interaction of human amyloid β-peptide (Aβ) with a lipid-raft model membrane under macromolecular crowding conditions that mimic the intracellular environment. Aβ is central to the development of Alzheimer's disease (AD) and has been studied extensively to determine the molecular mechanisms of Aβ-induced cellular dysfunctions underlying the pathogenesis of AD. According to evidence from spectroscopic studies, ganglioside clusters are key to the fibrillization process of Aβ. Gangliosides are a major component of glycosphingolipids and are acidic lipids of the central nervous system known to form so-called lipid rafts. In this study, the small unilamellar vesicle (SUV) membrane, composed of monosialogangliosides, cholesterol, and 1,2-dipalmitoyl- sn-glycero-3-phosphocholine, did not show any structural changes after the addition of Aβ under noncrowding conditions. However, the addition of Aβ under crowding conditions induced shape deformation and aggregation to SUV resulting in multilamellar stacking. The time evolution of the lamellar peak suggested the preferential cohesion or intercalation of the Aβ peptide into the interbilayer region. This phenomenon was only observed at the gel (L
β ) phase. These results suggest that an intracellular crowding environment promotes Aβ-membrane interaction and a selective accumulation of Aβ peptides into the interbilayer regions.- Published
- 2018
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6. Effect of protein-encapsulation on thermal structural stability of liposome composed of glycosphingolipid/cholesterol/phospholipid.
- Author
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Hirai M, Sato S, Kimura R, Hagiwara Y, Kawai-Hirai R, Ohta N, Igarashi N, and Shimizu N
- Subjects
- Animals, Brain, Cattle, Elasticity, Horses, Lipid Bilayers chemistry, Muscle, Skeletal, Pressure, Scattering, Small Angle, Spectrum Analysis, Synchrotrons, X-Ray Diffraction, Cholesterol chemistry, Gangliosides chemistry, Liposomes chemistry, Myoglobin chemistry, Phospholipids chemistry, Temperature
- Abstract
We have studied the thermal structural stability of liposomes encapsulating proteins by using synchrotron radiation small- and wide-angle X-ray scattering (SR-SWAXS). Liposomes are known to be effective drug-delivery systems (DDSs) because they can reduce drug toxicity due to biodegradability and biocompatibility and can offer promising carriers of various types of drugs. However, in spite of numerous studies of liposomes, physicochemical characteristics of liposomes entrapping proteins are rarely known. The liposome studied is characterized by the lipid composition (mixture of acidic glycosphingolipid (ganglioside)/cholesterol/phospholipid). Gangliosides are one of the major constituents of so-called lipid rafts playing the role of a platform of cell-signaling. We have found that the encapsulation of proteins elevates the thermal transition temperature of the liposome membrane and suppresses the deformation of its shape. The present results suggest that not only membrane proteins, but also water-soluble proteins affect liposome stability through the revalence between osmotic pressure and membrane elasticity. In addition, we have found the presence of the size-effect depending on the molar content of gangliosides in the liposome, indicating the ability of ganglioside molecule controlling both the size and effective surface charge of the liposome. The present results would have significance from two different points of view. One is the confinement effect of proteins within a limited space like cell, and the other is a stability of a new type of DDS using gangliosides. Due to the intrinsic properties, gangliosides are expected to be promising agents for targeting and long-circulation properties of liposomal DDSs.
- Published
- 2015
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7. X-ray scattering from immunostimulatory tetrapod-shaped DNA in aqueous solution to explore its biological activity-conformation relationship.
- Author
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Sanada Y, Sakamoto S, Shiomi T, Okobira T, Mylonas E, Ohta N, Yagi N, Nishikawa M, Akiba I, Takakura Y, and Sakurai K
- Subjects
- Animals, Cell Line, Computer Simulation, CpG Islands, DNA metabolism, Macrophages immunology, Mice, Models, Genetic, Models, Molecular, Scattering, Radiation, Solutions, Synchrotrons, Transition Temperature, Tumor Necrosis Factor-alpha metabolism, X-Rays, DNA chemistry, Nucleic Acid Conformation, Solvents chemistry, Water chemistry
- Abstract
We carried out synchrotron X-ray scattering experiments from four DNA supermolecules designed to form tetrapod shapes; these supermolecules had different sequences but identical numbers of total base pairs, and each contained an immunostimulatory CpG motif. We confirmed that the supermolecules did indeed form the expected tetrapod shape. The sample that had the largest radius of gyration (Rg) induced the most cytokine secretion from cultured immune cells. Structural analysis in combination with a rigid tetrapod model and an atomic scale DNA model revealed that the larger Rg can be ascribed to dissociation of the DNA double strands in the central connecting portion of the DNA tetrapod. This finding suggests that the biological activity is related to the ease with which single DNA strands can be formed.
- Published
- 2014
- Full Text
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8. External electric field effect on fluorescence spectra of pyrene in solution.
- Author
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Chiang HC and Ohta N
- Abstract
Electrophotoluminescence (E-PL) spectra, i.e., plots of the electric-field-induced change in photoluminescence intensity as a function of wavenumber, have been measured for pyrene solution. At high concentrations of pyrene where excimer fluorescence is observed along with the monomer fluorescence emitted from the locally excited state, both excimer fluorescence and monomer fluorescence are enhanced by application of electric fields. The results show that the nonradiative decay process at the excimer emitting state is decelerated by application of electric fields. It is also found that molecular polarizability of pyrene excimer is larger than that of pyrene monomer in the ground state by ~270 ± 90 Å(3), based on the analysis of the Stark shift of the excimer fluorescence.
- Published
- 2013
- Full Text
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9. Application of nanosecond pulsed electric fields into HeLa cells expressing enhanced green fluorescent protein and fluorescence lifetime microscopy.
- Author
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Awasthi K, Nakabayashi T, and Ohta N
- Subjects
- Apoptosis, Electricity, Electrodes, Gene Expression, Green Fluorescent Proteins genetics, HeLa Cells metabolism, Humans, Microscopy, Fluorescence, HeLa Cells cytology
- Abstract
An electrode microchamber has been constructed for applying nanosecond pulsed strong electric fields to living cells, and fluorescence lifetime microscopy (FLIM) has been used to investigate the effects of external electric fields on dynamics and function of HeLa cells expressing enhanced green fluorescent protein (EGFP). Both morphological change in cells and reduction of the fluorescence lifetime of EGFP have been observed after application of electric fields having a pulsed width of 50 ns and a strength of 4 MV m(-1), indicating that apoptosis, which is a programmed cell death, was induced by nanosecond pulsed electric fields and that fluorescence lifetime of EGFP decreased along with the induction of apoptosis. The reduction of the fluorescence lifetime occurred before the morphological change, indicating that FLIM provides a sensitive and noninvasive detection of the progress of apoptosis induced by application of nanosecond pulsed electric fields.
- Published
- 2012
- Full Text
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10. Intracellular pH sensing using autofluorescence lifetime microscopy.
- Author
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Ogikubo S, Nakabayashi T, Adachi T, Islam MS, Yoshizawa T, Kinjo M, and Ohta N
- Subjects
- Buffers, HeLa Cells, Humans, Hydrogen-Ion Concentration, Intracellular Space metabolism, NAD chemistry, NAD metabolism, Water chemistry, Intracellular Space chemistry, Microscopy, Fluorescence methods
- Abstract
Fluorescence lifetime images of reduced nicotinamide adenine dinucleotide (NADH) that is a key cofactor in cellular metabolism were obtained in a cell at various values of intracellular pH. The average fluorescence lifetime of NADH is found to become shorter monotonically with increasing pH, indicating that pH in a single cell can be determined by fluorescence lifetime imaging of NADH without adding exogenous fluorescent probes. The magnitude of the pH-induced lifetime change is higher in cells than that in buffer solution. The fluorescence lifetime of NADH is not uniform inside a cell; the fluorescence lifetime of nuclear NADH is shorter than that of mitochondrial NADH at each pH, and the magnitude of the pH-induced change is larger in nuclei than in other areas. The local electric field effect on the fluorescence lifetime is discussed since this effect may be one of the strong possibilities for the nonuniformity of the autofluorescence lifetime of NADH in cells., (© 2011 American Chemical Society)
- Published
- 2011
- Full Text
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11. Electric-field-induced changes in absorption and fluorescence of the green fluorescent protein chromophore in a PMMA film.
- Author
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Nakabayashi T, Hino K, Ohta Y, Ito S, Nakano H, and Ohta N
- Subjects
- Absorption, Animals, Electricity, Fluorescence, Materials Testing, Molecular Structure, Fluorescent Dyes chemistry, Green Fluorescent Proteins chemistry, Polymethyl Methacrylate chemistry, Spectrometry, Fluorescence methods
- Abstract
External electric field effects on absorption, fluorescence, and fluorescence decay of p-HBDI that is a model compound of the chromophore of GFP have been examined in a poly(methyl methacrylate) film. The electroabsorption spectrum is similar in shape to the first derivative of the absorption spectrum, which results from the difference in molecular polarizability between the ground state and the Franck-Condon excited state. The electrophotoluminescence spectrum is dominated by the corresponding fluorescence spectrum, indicating the enhancement of the fluorescence intensity in the presence of external electric fields. The direct measurements of the electric field effect on the fluorescence decay profile suggest that the field-induced deceleration of the nonradiative process contributes to the increase in the fluorescence intensity in the presence of electric fields.
- Published
- 2011
- Full Text
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12. Fluorescence decay dynamics of flavin adenine dinucleotide in a mixture of alcohol and water in the femtosecond and nanosecond time range.
- Author
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Nakabayashi T, Islam MS, and Ohta N
- Subjects
- Fluorescence, Molecular Structure, Spectrometry, Fluorescence methods, Time Factors, Alcohols chemistry, Flavin-Adenine Dinucleotide chemistry, Water chemistry
- Abstract
Fluorescence decays of flavin adenine dinucleotide (FAD) that is a typical autofluorescent species in cells and tissues have been measured in a mixture of alcohol and water in the femtosecond and nanosecond time range. The fluorescence lifetimes of both the stacked conformation between the isoalloxazine and adenine moieties in close proximity and the extended open conformation in water are affected by the addition of alcohol. The nanosecond fluorescence lifetime of the open conformation increases with decreasing dielectric constant of the medium, contributing to the enhancement of the fluorescence intensity of FAD in less dielectric media. The fluorescence lifetime of the open conformation is also affected by medium viscosity, suggesting that the photoexcited open conformation is quenched by the dynamic interaction between the two aromatic rings. The fluorescence component decaying in tens of picoseconds is attributed to the stacked conformation that shows the efficient fluorescence quenching due to the intramolecular electron transfer. The picosecond fluorescence lifetime of the stacked conformation increases with decreasing dielectric constant, suggesting the shift of the distribution of the stacked conformation to a longer intramolecular distance between the two aromatic rings in less dielectric media. The pre-exponential factor of the picosecond decaying component relative to that of the nanosecond one decreases with the increase of the alcohol concentration in the femtosecond time-resolved fluorescence, which demonstrates the increase in the population of the open conformation with the reduction of the dielectric constant. The possibility to evaluate the polar environment in a cell by the fluorescence lifetime of FAD is discussed based on the results obtained.
- Published
- 2010
- Full Text
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13. Electric-field-induced enhancement/quenching of photoluminescence of pi-conjugated polymer S3-PPV: excitation energy dependence.
- Author
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Mehata MS, Hsu CS, Lee YP, and Ohta N
- Abstract
The effects of electric field on absorption and photoluminescence (PL) of films of sulfide-substituted PPV derivative S3-PPV, poly[2-(phenyl)-3-(4'-(3,7-dimethyloctyloxy)phenyl)-1,4-phenylenevinylene-co-2-(11'-decyl sulfanylundecanyloxy)-5-methoxy-1,4-phenylene vinylene], were investigated. Electroabsorption (E-A) and electrophotoluminescence (E-PL) responses of S3-PPV show the Stark shifts, indicating a significant alternation in the molecular polarizability (Delta alpha) associated with the optical transitions. Field-induced enhancement or quenching is also observed for PL of S3-PPV, depending on the photoexcitation energy, whereas the shape of the PL spectra is independent of the excitation wavelength. The field effects on the decay profiles of PL indicate that the quenching results from a diminished population of the emitting states on excitation at 300 nm, whereas the PL is enhanced on excitation at 471 nm because the emitting state has an increased lifetime. The efficiency of field-assisted generation of electron-hole pairs produced through excitons monotonically increases with increasing excitation energy, and the nonradiative decay rate in the emitting state is diminished by electric fields in S3-PPV. The photoirradiation of S3-PPV in ambient air resulted in rapid degradation of the polymer film.
- Published
- 2010
- Full Text
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14. Electric field effects on absorption and fluorescence spectra of trimethylsilyl- and trimethylsilylethynyl-substituted compounds of pyrene in a PMMA film.
- Author
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Ara AM, Iimori T, Nakabayashi T, Maeda H, Mizuno K, and Ohta N
- Abstract
External electric field effects on absorption and fluorescence spectra of 1,3,6,8-tetrakis(trimethylsilyl)pyrene and 1,3,6,8-tetrakis(trimethylsilylethynyl)pyrene (TMSPy and TMS(E)Py, respectively) have been examined in a poly(methyl methacrylate) (PMMA) film at various concentrations at various temperatures. TMS(E)Py preferentially forms an aggregate in a PMMA film, as the concentration increases, indicating that the acetylenic groups enhance the pi-pi interactions between pyrene molecules. The change in molecular polarizability following excitation has been determined both for the monomer and for the aggregate, based on the electroabsorption spectra. The change in molecular polarizability following emission has also been determined in both compounds, based on the electrofluorescence spectra. TMSPy exhibits two excimer fluorescence emissions at high concentrations which are ascribed to the partially overlapping excimer and the sandwich-type excimer, respectively, besides the monomer fluorescence emitted from the locally excited state. The sandwich-type excimer fluorescence as well as monomer fluorescence is quenched by an electric field, whereas the fluorescence of the partially overlapping excimer is enhanced by an electric field. Excimer fluorescence of TMS(E)Py, which arises from the sandwich-type excimer, is quenched by an electric field at any temperature. Only one species of the partially overlapping excimer is confirmed in TMSPy, while no partially overlapping excimer is confirmed in TMS(E)Py.
- Published
- 2007
- Full Text
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15. External electric field effects on fluorescence of pyrene butyric acid in a polymer film: concentration dependence and temperature dependence.
- Author
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Ara AM, Iimori T, Yoshizawa T, Nakabayashi T, and Ohta N
- Abstract
Fluorescence spectra and electrofluorescence spectra (plots of the electric field-induced change in fluorescence intensity as a function of wavelength) have been measured at different temperatures for pyrene butyric acid (PBA) in a PMMA film at different concentrations. At a low concentration of 0.5 mol % where fluorescence emitted from the locally excited state of PBA (LE fluorescence) is dominant, LE fluorescence spectra show only the Stark shift in the presence of an electric field (F), which results from the difference in molecular polarizability between the ground and emitting states. At a high concentration of 10 mol % where the so-called sandwich-type excimer fluorescence (EX(1)) is dominant, both EX(1) and LE fluorescence are quenched by F. Another fluorescence assigned to a partially overlapped excimer (EX(2)) also exists at room temperature, and this emission is enhanced by F. As the temperature decreases, three fluorescence emissions whose electric field effects are different from each other become clear besides EX(1) and LE fluorescence, indicating that at least five fluorescence components exist at high concentrations at low temperatures. At a medium concentration of 5 mol % where EX(1) is comparable in intensity to the LE fluorescence, the intensity of EX(1) is not affected by F at any temperature, but LE fluorescence and EX(2) are markedly influenced by F at room temperature, and four fluorescence emissions are confirmed at low temperatures.
- Published
- 2006
- Full Text
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16. Electric-field-induced changes in absorption and emission spectra of CdS nanoparticles doped in a polymer film.
- Author
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Ohara Y, Nakabayashi T, Iwasaki K, Torimoto T, Ohtani B, Hiratani T, Konishi K, and Ohta N
- Abstract
Electric-field-induced changes in absorption and emission spectra of colloidal CdS nanoparticles ranging in size from 1.0 to 5.0 nm in diameter have been measured by using electric field modulation spectroscopy. The analysis of the electroabsorption spectra indicates that the dipole moment in the first exciton state becomes larger with increasing particle size. The presence of the large dipole moment following photoexcitation into the first exciton band suggests that the CdS nanoparticles have large CT character in the first exciton state. The quantum yields both of the exciton emission and of the trap emission are markedly reduced by application of an electric field. On the basis of the direct measurements of the field-induced change in emission decay profile, it is suggested that the field-induced de-enhancement of these emission yields results from the field-induced decreases both in lifetime and in initial population of each emitting state. It is also found that the emission intensity of CdS nanoparticles increases under the UV light irradiation in air and decreases in a vacuum condition and that fluorescence lifetime in the former case is longer than that in the latter. This enhancement and de-enhancement process in emission intensity is almost reversible at least in several cycles.
- Published
- 2006
- Full Text
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17. External electric field effects on absorption and fluorescence spectra of a fullerene derivative and its mixture with zinc-tetraphenylporphyrin doped in a PMMA film.
- Author
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Wahadoszamen M, Nakabayashi T, Kang S, Imahori H, and Ohta N
- Abstract
Electroabsorption and electrofluorescence spectra of a fullerene derivative, C60(C18)2, and its mixture with zinc-tetraphenylporphyrin (ZnTPP) have been measured by using electric field modulation spectroscopy. The change in dipole moment is significant in the electroabsorption spectra both of C60(C18)2 and of a complex composed of C60(C18)2 and ZnTPP, indicating that the excited states both of C60(C18)2 and of a complex between C60(C18)2 and ZnTPP have a large charge-transfer character. The fluorescence quantum yield of C60(C18)2 decreases in the presence of an electric field, which probably arises from the field-induced acceleration of the intramolecular nonradiative process of C60(C18)2 in the fluorescent state. In a mixture between ZnTPP and C60(C18)2, electrofluorescence spectra show the field-induced enhancement for the fluorescence of ZnTPP and the field-induced de-enhancement for the fluorescence both of C60(C18)2 and of the complex between ZnTPP and C60(C18)2. A theoretical analysis clearly shows that the field-induced enhancement of the ZnTPP fluorescence in a mixture results from the field-induced deceleration of the rate of the electron transfer from the excited ZnTPP to C60(C18)2. The standard free energy gap for the photoinduced electron-transfer process is estimated based on the theoretical simulation of the field-dependent fluorescence intensity.
- Published
- 2006
- Full Text
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18. The magnetic field effect in the presence of the electric field on fluorescence of a methylene-linked compound of pyrene and n,n-dimethylaniline doped in a polymer film.
- Author
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Medvedev ES, Mizoguchi M, and Ohta N
- Abstract
Recent experimental data by Mizoguchi and Ohta are analyzed under the assumption of fast equilibrium between the locally excited (LE), radical-ion-pair (RIP), and exciplex states. In the absence of the equilibrium, no magnetic field effect on the LE fluorescence would be observed. Owing to the equilibrium, the relative electric-field-induced changes of the quantum yields of the LE and exciplex emissions as functions of the magnetic field are linearly connected to each other. The electric field shifts the equilibrium from the LE state toward the RIP state. Predictions are made for the magnetic field effect on the fluorescence kinetics.
- Published
- 2006
- Full Text
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