Download or read book Time Resolved Fluorescence Studies of Molecular Alignment and Orientational Motion in Anisotropic Fluid Media written by Pamela Chandna and published by . This book was released on 1995 with total page 418 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Time Resolved Fluorescence Spectroscopy in Biochemistry and Biology written by R. Cundall and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 767 pages. Available in PDF, EPUB and Kindle. Book excerpt: At the time that the editors conceived the idea of trying to organize the meeting on which the contents of this volume are based and which became, in March 1980, a NATO Advanced Study Institute, the techniques of time-resolved fluorescence spectroscopy, in both the nanosecond and sub-nanosecond time-domains, might reasonably have been said to be coming of age, both in their execution and in the analysis and interpretation of the results obtained. These techniques, then as now, comprised mainly a number of pulse methods using laser, flash-lamp or, most recently, synchrotron radiation. In addition, significant developments in the more classical phase approach had also rendered that method popular, utilizing either modulation of an otherwise continuous source or, again recently, the ultra-rapid pulse rate attainable with a synchrotron source. In general terms, time-resolved fluorescence studies are capable, under appropriate conditions, of supplying direct kinetic information on both photophysics and various aspects of molecular, macromolecular and supramolecular structure and dynamics. The nanosecond and sub-nanosecond time-scales directly probed render these techniques particularly appropriate in studying relaxation and fluctuation processes in macromolecules, particularly biopolymers (e. g. proteins, nucleic acids), in supramolecular assemblies such as cell membranes, and in a variety of relatively simpler model systems.
Download or read book Index to Theses with Abstracts Accepted for Higher Degrees by the Universities of Great Britain and Ireland and the Council for National Academic Awards written by and published by . This book was released on 2001 with total page 842 pages. Available in PDF, EPUB and Kindle. Book excerpt: Theses on any subject submitted by the academic libraries in the UK and Ireland.
Download or read book Dynamics and Interactions in Complexx Nanostructured Molecular Systems Observed Through Time resolved Fluorescence Spectroscopy written by Joseph Edward Thomaz and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Time-correlated single photon counting (TCPSC) is a fluorescence spectroscopy technique used to investigate the behavior of chromophores from the hundreds of picoseconds to the tens of nanoseconds time regime. This technique works by measuring the time difference between two photon events: the initial excitation and the time at which a photon is emitted by the chromophore. Each measurement increments the appropriate bin in a histogram by one. As more and more measurements are made, the time-dependent fluorescent behavior is uncovered. With a single fluorescent decay, one can extract the fluorescent lifetime of a species or measure excitation transport. However, by varying the polarization of light exciting the chromophore relative to a fixed resolving polarizer, the orientational dynamics of a probe can also be extracted. The first set of experiments described in this thesis are measurements of orientational dynamics of the fluorophore, perylene, solvated in solutions of room temperature ionic liquids (RTILs). The D2h symmetry of perylene made it possible to extract dynamical information on both in-plane and out-of-plane reorientation from time-resolved fluorescence anisotropy measurements. The RTILs were a series of 1-alkyl-3-methylimidazolium tetrafluoroborates, where alkyl chain varied from butyl to decyl in increments of two and varying the water content. From the anisotropy, the corresponding friction coefficients were determined to eliminate the influence of changes in viscosity caused by both the addition of water and the different alkyl chain lengths. As chain length increased, the addition of water had less of an effect on the local alkyl environment surrounding the perylene. The friction coefficients generally increased with higher water contents. At high water content, the shortest alkyl chain --BmimBF4, broke this general trend, with both in-plane and out-of-plane rotational friction decreasing above a water content of one water per ion pair. While a lot can be learned through the measurements of single wavelength emissions, doing so greatly limits the types of experiments one can study. With complex models, it becomes difficult to justify the difference between different models as many will fit a single trace perfectly. By the construction of time-dependent emission spectra, much more information can be extracted. This is done by collecting fluorescent decays at regular intervals across the emission band under identical experimental conditions. The next study shows proton transfer in the nanoscopic water channels of polyelectrolyte fuel cell membranes using a photoacid, 8-hydroxypyrene-1,3,6-trisulfonic acid sodium salt (HPTS) into the channels. Three fully hydrated membranes, Nafion (DuPont) and two 3M membranes, were studied to determine the impact of different pendant chains and equivalent weights on proton transfer. Measurements of the HPTS protonated and deprotonated fluorescent bands' population decays provided information on the proton transport dynamics. The decay of the protonated band from ~0.5 ns to tens of ns is in part determined by dissociation and recombination with the HPTS. The dissociation and recombination is manifested as a power law component in the protonated band fluorescence decay. Proton transfer dynamics of HPTS in the aprotic solvent 1-methylimidazole (MeIm) were also investigated using fast fluorescence measurements. Wavelength-dependent population dynamics of HPTS in MeIm, resulting from its deprotonation following optical excitation, were collected over the entire fluorescence emission window. Analysis of the time-dependent fluorescence spectra reveal four distinct fluorescence bands that appear and decay on different time scales. We assign these bands to be the conventionally considered protonated (P) and deporotonated (D) HPTS states with 2 additional associated states (A1 and A2). The protonated states decays within the instrument response, but the remaining states were all able to be measured dynamically. The simplest kinetic model, P → A1 →A2→ D, in which the protonated state feeds into a single associated state which in turn feeds into the second associated state which deprotonates provided a quite poor fit. Detailed simulations were performed and identified the most likely kinetic model as protonated feeds into A1 which in turn feeds into both A2 and D, where A¬2 can return to A1 but not D. Another type of experiment in which the time-dependent spectra are necessary for the interpretation is in solvation dynamics of the fluorescent probe coumarin 153 (C153) in polyether sulfone membranes (PES 200) with an average pore size of ~350 nm. For instance, the structural dynamics of a series of 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (CnmimNTf2, n = 2, 4, 6, 10) room temperature ionic liquids confined in the PES 200 membranes. The solvation dynamics of C153 in the ionic liquids are multiexponential decay, and the slowest decay component of each bulk liquid matches the slowest component of the liquid dynamics measured by optical heterodyne-detected optical Kerr effect (OHD-OKE) experiments, which is single exponential. The fact that the slowest component of the Stokes shift matches the OHD-OKE data in all four liquids identifies this component of the solvation dynamics as arising from the complete structural randomization of the liquids. Although the pores in the PES membranes are large, confinement on the mesoscopic length scale results in substantial slowing of the dynamics for short chain ionic liquids, however, in the longest chain ionic liquid there was no noticeable confinement effect. The dynamic Stokes shift measurements report on structural relaxation, driven by a dipole created in a chromophore by its excitation from the ground electronic state to the S1 state. In another experiment, we were able to demonstrate that it is also possible to have an additional contribution from orientational relaxation of the Stokes shift chromophore. This effect, called reorientation-induced Stokes shift (RISS), can be observed when the reorientation of the chromophore and the solvent structural relaxation occur on similar time scales. Through a vector interaction, the electronic transition of the chromophore couples to its environment. The orientational diffusive motions of the chromophores will have a slight bias toward reducing the transition energy (red shift) as do the solvent structural diffusive motions. RISS is manifested in the polarization-dependence of C153 in poly(methyl methacrylate) (PMMA). Expressions are derived that permit determination of the structural dynamics by accounting for the RISS contributions. Using these equations, the structural dynamics of the medium can be measured for any system in which the directional interaction is well represented by a first order Stark effect and RISS is observed. The theoretical results are applied to the PMMA data, and the structural dynamics are obtained and discussed. Finally, the time-dependent photoluminescence of a broadband white light emitting perovskite -- 2,2'-(ethylenedioxy)bis(ethylammonium) tetrabromoplumbate, (EDBE)PbBr4 -- was measured using TCSPC. Time-dependent spectra were generated over a very broad time range from 100 ps to 100 ns. The main luminescent decay is a tri-exponential with time constants, 1.20 ns, 8.48 ns, and 21.75 ns.. Analysis of the time-dependent spectra showed a distinct spectral side peak which has a decay constant of 0.6 ns. After this peak decays, the emission line shape remains constant throughout the entire photoluminescent decay, demonstrating that the emission occurring from all wavelengths arises from a single ensemble. Therefore, the white light emission does not arise from a set of subensembles with different emission wavelengths and lifetimes. However, experiments on (EDBE)PbBr4 spin coated thin films luminescence decay is different, but it is still non-exponential and, like the crystal samples, occurs from a single ensemble after the relaxation of the rapidly decay side band. The spin coated samples have faster decays than the large single crystals.
Download or read book Time resolved Multirotational Fluorescence Anisotropy Measurements of Single Molecules to Characterize Conformational Subpopulations of Solution phase Intrinsically Disordered Proteins written by Alexander Kirby Foote and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes the development and utilization of time-correlated single photon counting (TCSPC) measurements on single biomolecules observed using an Anti-Brownian ELectrokinetic trap (ABEL trap). Single-molecule fluorescence spectroscopy is a well-developed tool for measuring heterogeneous, dynamic behaviors of biomolecules which would otherwise be lost in a bulk measurement, but its application in solution-based measurements are typically limited by the Brownian motion of unconstrained molecules, leading to limited observation times and signal. The ABEL trap works by correlating a molecule's location to the arrival time of each signal photon and applying an electronic feedback voltage which pushes the molecule towards the center of the confocal volume, thus extending the observation window and signal. TCSPC measurements have a high temporal resolution, and the large increase in signal photons afforded by utilization of the ABEL trap allows for statistically relevant populations of each time-bin within the time-resolved space. Chapter 1 will provide a brief introduction to both the ABEL trap instrument and TCSPC measurements. Chapter 2 describes the contributions I have made in refining the trapping capabilities of the ABEL trap for use in the Goldsmith lab, increasing the location accuracy, collection efficiency, photobleaching limit, and signal intensity of the trapped molecule. Chapter 3 describes the time-resolved anisotropy measurements of single tau proteins, and the development of a Gaussian-weighted Kalman filter which was used to sort the rotational parameters of the observed molecules. Chapter 4 describes my work in extending our instrument's capabilities to include Forster Resonance Energy Transfer measurements, and applying those measurements to include 2-Dimensional Fluorescence Lifetime Correlation Spectroscopy analysis on DNA hairpin loops.
Download or read book The Molecular Dynamics of Liquid Crystals written by G.R. Luckhurst and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 612 pages. Available in PDF, EPUB and Kindle. Book excerpt: Liquid-crystalline phases are now known to be formed by an ever growing range of quite diverse materials, these include those of low molecular weight as well as the novel liquid-crystalline polymers, such phases can also be induced by the addition of a solvent to amphiphilic systems leading to lyotropic liquid crystals. Irrespective of the structure of the constituent molecules these numerous liquid-cl)'Stailine phases are characterised by their long range orientational order. In addition certain phases exhibit elements of long range positional order. Our understanding, both experimental and theoretical, at the molecular level of the static behaviour of these fascinating and important materials is now well advanced. In contrast the influence of the long range order; both orientational and positional, on the molecular dynamics in liquid Cl)'Stais is less well understood. In an attempt to address this situation a NATO Advanced Study Institute devoted to liquid ctystal dynamics was held at n Ciocco, Barga, Italy in September 1989. This brought together experimentalists and theoreticians concerned with the various dynamical processes occurring in all liquid crystals. The skills of the participants was impressively wide ranging; they spanned the experimental techniques used in the study of molecular dynamics, the nature of the systems investigated and the theoretical models employed to understand the results. While much was learnt it was also recognised that much more needed to be done in order to advance our understanding of molecular dynamics in liquid Cl)'Stais.
Download or read book An Introduction to Laser Spectroscopy written by David L. Andrews and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the new edition the editors have preserved the basic concept and structure, with the involvement of some new authors - all recognized experts in laser spectroscopy. Each chapter addresses a different technique, providing a review and analysis of the current status, and reporting some of the latest achievements. With the key formulas and methods detailed in many sections, this text represents a practicable handbook of its subject. It will be a valuable tool both for specialists to keep abreast of developments and for newcomers to the field needing an accessible introduction to specific methods of laser spectroscopy - and also as a resource for primary references.
Download or read book Annual Review of Physical Chemistry written by Gerhard Krohn Rollefson and published by Annual Reviews. This book was released on 1977-10 with total page 592 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides abstracts and review articles on topics in physical chemistry.
Download or read book Encyclopedia of Spectroscopy and Spectrometry A H written by John C. Lindon and published by . This book was released on 2000 with total page 1008 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Encyclopedia provides coverage of current knowledge in the field of spectroscopy and related areas.
Download or read book Encyclopedia of Spectroscopy and Spectrometry written by and published by . This book was released on 2000 with total page 1004 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Biological NMR Spectroscopy written by John L. Markley and published by Oxford University Press. This book was released on 1997-01-30 with total page 375 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a critical assessment of progress on the use of nuclear magnetic resonance spectroscopy to determine the structure of proteins, including brief reviews of the history of the field along with coverage of current clinical and in vivo applications. The book, in honor of Oleg Jardetsky, one of the pioneers of the field, is edited by two of the most highly respected investigators using NMR, and features contributions by most of the leading workers in the field. It will be valued as a landmark publication that presents the state-of-the-art perspectives regarding one of today's most important technologies.
Download or read book Physics Briefs written by and published by . This book was released on 1993 with total page 1116 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Green Fluorescent Protein written by Martin Chalfie and published by John Wiley & Sons. This book was released on 2005-11-18 with total page 486 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the discovery of the gene for green fluorescent protein (GFP), derived from jellyfish, this protein that emits a green glow has initiated a revolution in molecular biosciences. With this tool, it is now possible to visualize nearly any protein of interest in any cell or tissue of any species. Since the publication of the first edition, there have been tremendously significant technological advances, including development of new mutant variants. Proteins are now available in yellow and blue, and Novel Fluorescent Proteins (NFPs) have expanded their utility in developing biosensors, biological markers, and other biological applications. This updated, expanded new edition places emphasis on the rise of NFPs, including new chapters on NFP properties with detailed protocols, applications of GFPs and NFPs in industry research, and biosensors. This book provides a solid theoretical framework, along with detailed, practical guidance on use of GFPs and NFPs with discussion of potential pitfalls. The expert contributors provide real examples in showing how to tailor GFP/NFP to specific systems, maximize expression, and enhance detection.
Download or read book Liquid Crystal Colloids written by Igor Muševič and published by Springer. This book was released on 2017-05-14 with total page 313 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book brings together the many concepts and discoveries in liquid crystal colloids contributed over the last twenty years and scattered across numerous articles and book chapters. It provides both a historical overview of the development of the field and a clear perspective on the future applications in photonics. The book covers all phenomena observed in liquid crystal colloids with an emphasis on experimental tools and applications of topology in condensed matter, as well as practical micro-photonics applications. It includes a number of spectacular manifestations of new topological phenomena not found or difficult to observe in other systems. Starting from the early works on nematic colloids, it explains the basics of topological defects in ordered media, charge and winding, and the elastic forces between colloidal particles in nematics. Following a detailed description of experimental methods, such as optical tweezing and particle tracking, the book eases the reader into the theoretical part, which deals with elastic deformation of nematic liquid crystals due to inclusions and surface alignment. This is discussed in the context of basic mean field Landau-de Gennes Q-tensor theory, with a brief explanation of the free-energy minimization numerical methods. There then follows an excursion into the topology of complex nematic colloidal structures, colloidal entanglement, knotting and linking. Nematic droplets, shells, handlebodies and chiral topological structures are addressed in separate chapters. The book concludes with an extensive chapter on the photonic properties of nematic dispersions, presenting the concept of integrated soft matter photonics and discussing the concepts of nematic and chiral nematic microlasers, surface-sensitive photonic devices and smectic microfibers. The text is complemented by a large bibliography, explanatory sketches and beautiful micrographs.
Download or read book Fluorescent Biomolecules written by David M. Jameson and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 459 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume is based on an international symposium held during September 9-12, 1986 in Bocca di Magra, Italy. The intent of the organizers was to bring together expert practitioners of fluorescence spectroscopy, particularly as applied to biological systems, to assess recent developments in the field and discuss future directions. At the same time the meeting was intended to honor the singular and outstanding scientific career of Gregorio Weber on the occasion of his seventieth birthday. Gregorio Weber is truly the pioneer in the application of fluores cence methods to biochemistry and biophysics. A complete list of his scientific contributions to fluorescence and to protein biochemistry is beyond the scope of this preface. Suffice it to say that since his initial landmark articles on fluorescence, published in the late 1940's and early 1950's, Gregorio Weber has continued to make seminal contribu tions to both the theory and practice of fluorescence and, contrary to many who might be tempted to rest on their laurels, he shows no signs of slackening his pace. In addition to his more obvious tangible contributions to the scientific field, Gregorio Weber has made equally valuable contributions of another type. Specifically, he has had the most profound impact, both profeSSionally and personally, on generations of young scientists.
Download or read book New Trends in Fluorescence Spectroscopy written by Bernard Valeur and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: This first volume in the new Springer Series on Fluorescence brings together fundamental and applied research from this highly interdisciplinary and field, ranging from chemistry and physics to biology and medicine. Special attention is given to supramolecular systems, sensor applications, confocal microscopy and protein-protein interactions. This carefully edited collection of articles is an invaluable tool for practitioners and novices.
Download or read book Advanced Time Correlated Single Photon Counting Techniques written by Wolfgang Becker and published by Springer Science & Business Media. This book was released on 2005-12-19 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt: In 1984 Desmond O’Connor and David Phillips published their comprehensive book „Time-correlated Single Photon Counting“. At that time time-correlated s- gle photon counting, or TCSPC, was used primarily to record fluorescence decay functions of dye solutions in cuvettes. From the beginning, TCSPC was an am- ingly sensitive and accurate technique with excellent time-resolution. However, acquisition times were relatively slow due to the low repetition rate of the light sources and the limited speed of the electronics of the 70s and early 80s. Moreover, TCSPC was intrinsically one-dimensional, i.e. limited to the recording of the wa- form of a periodic light signal. Even with these limitations, it was a wonderful te- nique. More than 20 years have elapsed, and electronics and laser techniques have made impressive progress. The number of transistors on a single chip has approximately doubled every 18 months, resulting in a more than 1,000-fold increase in compl- ity and speed. The repetition rate and power of pulsed light sources have increased by about the same factor.
