The Role of Diffusion in NMR Proton Relaxation Enhancement by Ferritin
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Neutron Spin Echo Spectroscopy
Neutron Spin Echo Spectroscopy Peter Fouquet [email protected] Institut Laue-Langevin Grenoble, France Oxford Neutron School 2017 What you are supposed to learn in this tutorial 1. The length and time scales that can be studied using NSE spectroscopy 2. The measurement principle of NSE spectroscopy 3. Discrimination techniques for coherent, incoherent and magnetic dynamics 4. To which scientific problems can I apply NSE spectroscopy? NSE-Tutorial Mind Map Quantum Mechanical Model Resonance Spin-Echo Classical Model Measurement principle “4-point Echo” NSE spectroscopy Instrument Frustrated Components Magnets Bio- molecules Time/Space Map NSE around Surface the globe Diffusion Science Cases Paramagnetic Spin Echo Experiment planning and Interpretation Diffusion Glasses Polymers Models Coherent and Incoherent Scattering Data Treatment The measurement principle of neutron spin echo spectroscopy (quantum mechanical model) • The neutron wave function is split by magnetic fields • The 2 wave packets arrive at magnetic coil 1 magnetic coil 2 polarised sample the sample with a time neutron difference t • If the molecules move between the arrival of the first and second wave packet then coherence is lost • The intermediate scattering t λ3 Bdl function I(Q,t) reflects this ∝ loss in coherence strong wavelength field integral dependence Return The measurement principle of neutron spin echo spectroscopy Dynamic Scattering NSE spectra for diffusive motion Function S(Q,ω) G(R,ω) I(Q,t) = e-t/τ Fourier Transforms temperature up ⇒ τ down Intermediate VanHove -
4 Nuclear Magnetic Resonance
Chapter 4, page 1 4 Nuclear Magnetic Resonance Pieter Zeeman observed in 1896 the splitting of optical spectral lines in the field of an electromagnet. Since then, the splitting of energy levels proportional to an external magnetic field has been called the "Zeeman effect". The "Zeeman resonance effect" causes magnetic resonances which are classified under radio frequency spectroscopy (rf spectroscopy). In these resonances, the transitions between two branches of a single energy level split in an external magnetic field are measured in the megahertz and gigahertz range. In 1944, Jevgeni Konstantinovitch Savoiski discovered electron paramagnetic resonance. Shortly thereafter in 1945, nuclear magnetic resonance was demonstrated almost simultaneously in Boston by Edward Mills Purcell and in Stanford by Felix Bloch. Nuclear magnetic resonance was sometimes called nuclear induction or paramagnetic nuclear resonance. It is generally abbreviated to NMR. So as not to scare prospective patients in medicine, reference to the "nuclear" character of NMR is dropped and the magnetic resonance based imaging systems (scanner) found in hospitals are simply referred to as "magnetic resonance imaging" (MRI). 4.1 The Nuclear Resonance Effect Many atomic nuclei have spin, characterized by the nuclear spin quantum number I. The absolute value of the spin angular momentum is L =+h II(1). (4.01) The component in the direction of an applied field is Lz = Iz h ≡ m h. (4.02) The external field is usually defined along the z-direction. The magnetic quantum number is symbolized by Iz or m and can have 2I +1 values: Iz ≡ m = −I, −I+1, ..., I−1, I. -
Relaxation 11/26/2020 | Page 2
RUPRECHT-KARLS- UNIVERSITY HEIDELBERG Computer Assisted Clinical Medicine Prof. Dr. Lothar Schad Master‘s Program in Medical Physics 11/26/2020 | Page 1 Physics of Imaging Systems Basic Principles of Magnetic Resonance Imaging III Prof. Dr. Lothar Schad Chair in Computer Assisted Clinical Medicine Faculty of Medicine Mannheim University of Heidelberg Theodor-Kutzer-Ufer 1-3 D-68167 Mannheim, Germany [email protected] www.ma.uni-heidelberg.de/inst/cbtm/ckm/ RUPRECHT-KARLS- UNIVERSITY HEIDELBERG Computer Assisted Clinical Medicine Prof. Dr. Lothar Schad Relaxation 11/26/2020 | Page 2 Relaxation Seite 1 1 RUPRECHT-KARLS- UNIVERSITY HEIDELBERG Computer Assisted Clinical Medicine Prof. Dr. Lothar Schad Magnetization: M and M 11/26/2020 | Page 3 z xy longitudinal magnetization: Mz transversal magnetization: Mxy transversal magnetization: Mxy - phase synchronization after a 90°-pulse - the magnetic moments of the probe start to precede around B1 leading to a synchronization of spin packages → Mxy - after 90°-pulse Mxy = M0 RUPRECHT-KARLS- UNIVERSITY HEIDELBERG Computer Assisted Clinical Medicine Prof. Dr. Lothar Schad Movie: M and M 11/26/2020 | Page 4 z xy source: Schlegel and Mahr. “3D Conformal Radiation Therapy: A Multimedia Introduction to Methods and Techniques" 2007 Seite 2 2 RUPRECHT-KARLS- UNIVERSITY HEIDELBERG Computer Assisted Clinical Medicine Prof. Dr. Lothar Schad Longitudinal Relaxation Time: T1 11/26/2020 | Page 5 thermal equilibrium excited state after 90°-pulse: -N-1/2 = N+1/2 and Mz = 0, Mxy = M0 after RF switched off: - magnetization turns back to thermal equilibrium - Mz = M0, Mxy = 0 → T1 relaxation longitudinal relaxation time T1 spin-lattice-relaxation time T1 RUPRECHT-KARLS- UNIVERSITY HEIDELBERG Computer Assisted Clinical Medicine Prof. -
Effect of Electronegative Elements on the NMR Chemical Shift in Some Simple R-X Organic Compounds
IOSR Journal of Applied Physics (IOSR-JAP) e-ISSN: 2278-4861.Volume 6, Issue 4 Ver. III (Jul-Aug. 2014), PP 45-56 www.iosrjournals.org Effect of electronegative elements on the NMR chemical shift in some simple R-X organic compounds Muhammad A. AL-Jalali1, Yahia M. Mahzia2 1Physics Department, Faculty of Science, Taif University, Taif, AL-Haweiah, , P. O. Box 888, Zip code 21974, Kingdom of Saudi Arabia 2Physics Department, Faculty of Science, Damascus University, Damascus, Syrian Arab Republic. Abstract: Organic halides and other organic compounds that contain electronegative elements, have a strong chemical shift and a brilliant NMR spectrum will prevail. Relationship between 1H, 13C NMR chemical shift and Electronegativity in some simple R-X organic compounds (X=F, Cl, Br, I, O, H, ...R=CH3 or CH3-CH2-) give nonlinear equation, as well as a power series equation appears between nuclear magnetogyric ratio, magnetic shielding constant and chemical shift, which are not included in the theoretical expressions. More investigations required to remove the discrepancy between the theoretical and the experimental results. Keywords: Electronegativity, chemical shift, shielding constant, magnetogyric ratio. I. Introduction Nuclear magnetic resonance, or NMR is a physical phenomenon was observed in 1945[1,2], which occurs when the nuclei of certain atoms, firstly, subject to nuclear Zeeman effect[3,4,5]will Precession with the Larmor frequency [6, 7]. Secondly, exposed to an oscillating electromagnetic field (radio waves), then if the radio wave frequency exactly matches the precession frequency, the resonance phenomenon will happen and this is the so-called nuclear magnetic resonance. However, experimentally, it has been noticed [8, 9, 10] that a nucleus may have a different resonant frequency for a given applied magnetic field in different chemical compounds, this difference in resonant frequency is called the chemical shift or sometimes fine structure. -
The Chemical Shift Chem 117 the Chemical Shift Key Questions (1) What Controls Proton Chemical Shifts? Eugene E
E. Kwan Lecture 2: The Chemical Shift Chem 117 The Chemical Shift Key Questions (1) What controls proton chemical shifts? Eugene E. Kwan January 26, 2012. H H H H 0.86 ppm 5.28 2.88 Br Scope of Lecture 16.4 proton chemical problem shift trends diamagnetic vs. (2) What controls carbon chemical shifts? solving paramagnetic O O shielding O CH2 H C OH the chemical 3 H3C CH3 basic DEPT 49.2 49.2 40.5 69.2 and COSY shift H-bonding and solvent (3) What are COSY and DEPT? What useful information effects spin-orbit coupling, can they give about a structure? carbon chemical effect of unsaturation shift trends 123 Helpful References 10 0 1. Nuclear Magnetic Resonance Spectroscopy... Lambert, J.B.; 1 Mazzola, E.P. Prentice-Hall, 2004. (Chapter 3) 2 2. The ABCs of FT-NMR Roberts, J.D. University Science Books, 2000. (Chapter 10) 3 3. Spectrometric Identification of Organic Compounds (7th ed.) Silverstein, R.M.; Webster, F.X.; Kiemle, D.J. Wiley, 2005. (useful charts in the appendices of chapters 2-4) 10 4. Organic Structural Spectroscopy Lambert, J.B.; Shurvell, H.F.; Lightner, D.A.; Cooks, R.G. Prentice-Hall, 1998. I thank Professors William F. Reynolds (Toronto) and Gene Mazzola (Maryland/FDA) for providing some useful 5. Organic Structure Analysis Crews, P. Rodriguez, J.; Jaspars, material for this lecture. The section on chemical shifts M. Oxford University Press, 1998. is based on the discussion in Chapter 3 of reference 1. E. Kwan Lecture 2: The Chemical Shift Chem 117 Proton Chemical Shifts Clearly, the regions overlap: reference: Lambert and Mazzola, Chapter 3. -
NMR Chemical Shifts of Common Laboratory Solvents As Trace Impurities
7512 J. Org. Chem. 1997, 62, 7512-7515 NMR Chemical Shifts of Common Laboratory Solvents as Trace Impurities Hugo E. Gottlieb,* Vadim Kotlyar, and Abraham Nudelman* Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel Received June 27, 1997 In the course of the routine use of NMR as an aid for organic chemistry, a day-to-day problem is the identifica- tion of signals deriving from common contaminants (water, solvents, stabilizers, oils) in less-than-analyti- cally-pure samples. This data may be available in the literature, but the time involved in searching for it may be considerable. Another issue is the concentration dependence of chemical shifts (especially 1H); results obtained two or three decades ago usually refer to much Figure 1. Chemical shift of HDO as a function of tempera- more concentrated samples, and run at lower magnetic ture. fields, than today’s practice. 1 13 We therefore decided to collect H and C chemical dependent (vide infra). Also, any potential hydrogen- shifts of what are, in our experience, the most popular bond acceptor will tend to shift the water signal down- “extra peaks” in a variety of commonly used NMR field; this is particularly true for nonpolar solvents. In solvents, in the hope that this will be of assistance to contrast, in e.g. DMSO the water is already strongly the practicing chemist. hydrogen-bonded to the solvent, and solutes have only a negligible effect on its chemical shift. This is also true Experimental Section for D2O; the chemical shift of the residual HDO is very NMR spectra were taken in a Bruker DPX-300 instrument temperature-dependent (vide infra) but, maybe counter- (300.1 and 75.5 MHz for 1H and 13C, respectively). -
Princeton University, Physics 311/312; NMR Andthe Spin Echo 1
Princeton University, Physics 311/312; NMR andthe Spin Echo 1 NUCLEAR MAGNETIC RESONANCE AND THE SPIN ECHO Introduction In this experiment we investigate the properties of several materials using pulsed nuclear magnetic resonance (NMR). The NMR technique is used extensively for medical imaging and as a tool in condensed matter and materials physics. The physical mechanism behind NMR is a resonant transition between the energy states of a precessing spin 1/2 particle, specifically a proton, in an external magnetic field. By illuminating the atoms in a liquid, gas or solid with pulses of radio frequency (RF) radiation of various lengths, one can examine the interaction of the spins with the external field, with each other, and with the “lattice.” À Consider a particle with classical angular momentum J in a constant external magnetic field ¼ .The = h  particle has a magnetic moment due to its angular momentum. From the classical equation of À motion we know that if ¼ and are not parallel, the magnetic moment will precess about the magnetic ! = À À ¼ field. The frequency of this precession, ¼ , is independent of the angle between and and is called the Larmor frequency. À In NMR, a sample is placed in a constant magnetic field ¼ as shown in Figure 1. All the spins of À the protons try to align with ¼ but the thermal motion (phonons) of the lattice, to some extent, prevents Å À ¼ this. There is still though a net magnetization, ¼ , parallel to . To manipulate the magnetization, we À apply an RF field perpendicular to ¼ . This results in an oscillating magnetic field that can be viewed as the superposition of two counter-rotating components; only the component rotating in the same direction as that of the spin’s precession has significant effect. -
Double Spin-Echo Sequence for Rapid Spectroscopic Imaging of Hyperpolarized 13C
Journal of Magnetic Resonance 187 (2007) 357–362 www.elsevier.com/locate/jmr Communication Double spin-echo sequence for rapid spectroscopic imaging of hyperpolarized 13C Charles H. Cunningham a,*, Albert P. Chen b, Mark J. Albers b, John Kurhanewicz b, Ralph E. Hurd c, Yi-Fen Yen c, John M. Pauly d, Sarah J. Nelson b, Daniel B. Vigneron b a Department of Medical Biophysics, Sunnybrook Health Sciences Centre, 2075 Bayview Ave., Toronto, Ont., Canada M4N 3M5 b Department of Radiology, University of California at San Francisco, San Francisco, CA, USA c GE Healthcare Technologies, Menlo Park, CA, USA d Department of Electrical Engineering, Stanford University, Stanford, CA, USA Received 2 February 2007; revised 17 April 2007 Available online 2 June 2007 Abstract Dynamic nuclear polarization of metabolically active compounds labeled with 13C has been introduced as a means for imaging met- abolic processes in vivo. To differentiate between the injected compound and the various metabolic products, an imaging technique capa- ble of separating the different chemical-shift species must be used. In this paper, the design and testing of a pulse sequence for rapid magnetic resonance spectroscopic imaging (MRSI) of hyperpolarized 13C is presented. The pulse sequence consists of a small-tip exci- tation followed by a double spin echo using adiabatic refocusing pulses and a ‘‘flyback’’ echo-planar readout gradient. Key elements of the sequence are insensitivity to calibration of the transmit gain, the formation of a spin echo giving high-quality spectral information, and a small effective tip angle that preserves the magnetization for a sufficient duration. -
Article Is Available Online Is One of the Most Comprehensive Ways to Envision Such at Doi:10.5194/Bg-13-2257-2016-Supplement
Biogeosciences, 13, 2257–2277, 2016 www.biogeosciences.net/13/2257/2016/ doi:10.5194/bg-13-2257-2016 © Author(s) 2016. CC Attribution 3.0 License. Molecular characterization of dissolved organic matter from subtropical wetlands: a comparative study through the analysis of optical properties, NMR and FTICR/MS Norbert Hertkorn1, Mourad Harir1, Kaelin M. Cawley2, Philippe Schmitt-Kopplin1, and Rudolf Jaffé2 1Helmholtz Zentrum München, German Research Center for Environmental Health, Research Unit Analytical Biogeochemistry (BGC), Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany 2Southeast Environmental Research Center, and Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL 33199, USA Correspondence to: Rudolf Jaffé (jaffer@fiu.edu) Received: 23 July 2015 – Published in Biogeosciences Discuss.: 25 August 2015 Revised: 22 December 2015 – Accepted: 7 February 2016 – Published: 19 April 2016 Abstract. Wetlands provide quintessential ecosystem ser- relative disparity was largest between the Everglades long- vices such as maintenance of water quality, water supply and short-hydroperiod samples, whereas Pantanal and Oka- and biodiversity, among others; however, wetlands are also vango samples were more alike among themselves. Other- among the most threatened ecosystems worldwide. Natural wise, molecular divergence was most obvious in the case dissolved organic matter (DOM) is an abundant and criti- of unsaturated protons (δH > 5 ppm). 2-D NMR spectroscopy cal component in wetland biogeochemistry. This study de- for a particular sample revealed a large richness of aliphatic scribes the first detailed, comparative, molecular characteri- and unsaturated substructures, likely derived from microbial zation of DOM in subtropical, pulsed, wetlands, namely the sources such as periphyton in the Everglades. -
Neutron Spin Echo Spectroscopy
Neutron Spin Echo Spectroscopy Peter Fouquet [email protected] Institut Laue-Langevin Grenoble, France September 2014 Hercules Specialized Course 17 - Grenoble What you are supposed to learn in this lecture 1. The length and time scales that can be studied using NSE spectroscopy 2. The measurement principle of NSE spectroscopy 3. Discrimination techniques for coherent, incoherent and magnetic dynamics 4. To which scientific problems can I apply NSE spectroscopy? The measurement principle of neutron spin echo spectroscopy (quantum mechanical model) The neutron wave function is split by magnetic fields magnetic coil 1 magnetic coil 2 polarised sample The 2 wave packets arrive at neutron the sample with a time difference t If the molecules move between the arrival of the first and second wave packet then coherence is lost t λ3 Bdl The intermediate ∝ scattering function I(Q,t) reflects this loss in coherence strong wavelength field integral dependence The measurement principle of neutron spin echo spectroscopy Dynamic Scattering NSE spectra for diffusive motion Function S(Q,ω) G(R,ω) I(Q,t) = e-t/τ Fourier Transforms temperature up ⇒ τ down Intermediate VanHove Correlation Scattering Function Function I(Q,t) G(R,t) Measured with Neutron Spin Echo (NSE) Spectroscopy Neutron spin echo spectroscopy in the time/space landscape NSE is the neutron spectroscopy with the highest energy resolution The time range covered is 1 ps < t < 1 µs (equivalent to neV energy resolution) The momentum transfer range is 0.01 < Q < 4 Å-1 Spin Echo The measurement principle -
Echo-Detected Electron Paramagnetic Resonance Spectra of Spin-Labeled Lipids in Membrane Model Systems Denis A
Subscriber access provided by MPI FUR BIOPHYS CHEM Article Echo-Detected Electron Paramagnetic Resonance Spectra of Spin-Labeled Lipids in Membrane Model Systems Denis A. Erilov, Rosa Bartucci, Rita Guzzi, Derek Marsh, Sergei A. Dzuba, and Luigi Sportelli J. Phys. Chem. B, 2004, 108 (14), 4501-4507• DOI: 10.1021/jp037249y • Publication Date (Web): 16 March 2004 Downloaded from http://pubs.acs.org on March 24, 2009 More About This Article Additional resources and features associated with this article are available within the HTML version: • Supporting Information • Links to the 1 articles that cite this article, as of the time of this article download • Access to high resolution figures • Links to articles and content related to this article • Copyright permission to reproduce figures and/or text from this article The Journal of Physical Chemistry B is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 J. Phys. Chem. B 2004, 108, 4501-4507 4501 Echo-Detected Electron Paramagnetic Resonance Spectra of Spin-Labeled Lipids in Membrane Model Systems Denis A. Erilov,†,| Rosa Bartucci,*,† Rita Guzzi,† Derek Marsh,§ Sergei A. Dzuba,‡ and Luigi Sportelli† Dipartimento di Fisica and Unita` INFM, UniVersita` della Calabria, I-87036 ArcaVacata di Rende (CS), Italy, Abteilung Spektroskopie, Max-Planck-Institut fur biophysikalische Chemie, 37077 Gottingen, Germany, and Institute of Chemical Kinetics and Combustion, Russian Academy of Science, 630090 NoVosibirsk, Russian Federation ReceiVed: October 28, 2003; In Final Form: February 5, 2004 The dynamics of spin-labeled lipid chains in the low-temperature phases of dipalmitoyl phosphatidylcholine (DPPC) membranes, with and without equimolar cholesterol, have been investigated by pulsed electron paramagnetic resonance (EPR) spectroscopy. -
A New Mechanism for Electron Spin Echo Envelope Modulation ͒ John J
THE JOURNAL OF CHEMICAL PHYSICS 122, 174504 ͑2005͒ A new mechanism for electron spin echo envelope modulation ͒ John J. L. Mortona Department of Materials, Oxford University, Oxford OX1 3PH, United Kingdom Alexei M. Tyryshkin Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544 Arzhang Ardavan Clarendon Laboratory, Department of Physics, Oxford University, Oxford OX1 3PU, United Kingdom Kyriakos Porfyrakis Department of Materials, Oxford University, Oxford OX1 3PH, United Kingdom S. A. Lyon Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544 G. Andrew D. Briggs Department of Materials, Oxford University, Oxford OX1 3PH, United Kingdom ͑Received 21 January 2005; accepted 18 February 2005; published online 2 May 2005͒ Electron spin echo envelope modulation ͑ESEEM͒ has been observed for the first time from a coupled heterospin pair of electron and nucleus in liquid solution. Previously, modulation effects in spin-echo experiments have only been described in liquid solutions for a coupled pair of homonuclear spins in nuclear magnetic resonance or a pair of resonant electron spins in electron paramagnetic resonance. We observe low-frequency ESEEM ͑26 and 52 kHz͒ due to a new mechanism present for any electron spin with SϾ1/2 that is hyperfine coupled to a nuclear spin. In ͑ ͒ ͑ ͒ our case these are electron spin S=3/2 and nuclear spin I=1 in the endohedral fullerene N@C60. The modulation is shown to arise from second-order effects in the isotropic hyperfine coupling of an electron and 14N nucleus. © 2005 American Institute of Physics. ͓DOI: 10.1063/1.1888585͔ I. INTRODUCTION electron spins with different Larmor frequencies͒ results in no modulation effects from this mechanism: The heterospin Measuring the modulation of a spin echo in pulsed coupling energy changes its sign upon application of the re- magnetic-resonance experiments has become a popular tech- focusing pulse ͑because only one spin flips͒, and the magne- nique for studying weak spin-spin couplings.