Principles Of Nuclear Magnetic Resonance Research Articles

Teknik Pemeriksaan MRI Genu Dengan Penambahan Sequence Axial 3D Spoiled Gradient Recalled Echo

Magnetic Resonance Imaging (MRI) is a medical diagnostic imaging technique that works on the principle of nuclear magnetic resonance. MRI aircraft can produce diagnostic images of the inside of the human body in both sagittal, coronal, and transverse cuts, Magnetic resonance imaging (MRI) is a widely accepted non-invasive technique for the evaluation of cartilage lesions. The femur, tibia, fibula, and patella are united into one complex group by ligaments. According to Moeller, Genu Examination uses STIR Sequence, Sagital T2 Weighted Fat saturated, Sagittal 3D GRE, Proton Density weighted fat saturated T1 Coronal. The author's purpose in conducting this study is because Genu Examination at one of the Jakarta Hospital in the Case of Soft Tissue Tumor, Meniscus Tear and Oesteoarthritis added the Axial 3D SPGR sequence. The research method used is descriptive research with an observational approach. Data collection was carried out on June 5 to August 31 using Mri GE aircraft with a power of 1.5 Tesla. The patient samples used in this study were three patients with clinical Soft Tissue Tumor, Meniscus Tear, and Osteoarthritis. Data collection was carried out through observation, interviews and Genu Examination Documentation with the addition of Axial 3D SPGR. The examination is carried out using Quad Knee Coil, the patient's position is supine, feet first. The sequences used in the examination at one of the Jakarta hospitals are Axial Proton Density Fat saturated, Sagital Proton Density Fat saturated, Sagital T2, Coronal Proton Density Fat saturated, Coronal STIR. The role of the Axial 3D SPGR sequence is to evaluate articular cartilage due to its clear depiction of cartilage morphology and high signal to noise ratio (SNR) images.

Principles of nuclear magnetic resonance and its applications in medication

There is no doubt that the Nuclear Magnetic Resonance is one of the most fascinating inventions in modern era. Nuclear magnetic resonance is the physical process of nucleus in the body, which align with the direction of magnetic field under the action of external magnetic field, resonant absorb the radio frequency pulse of a certain frequency. NMR spectroscopy is a branch of spectroscopy in which the resonant frequency is in the RF band and the corresponding transition is a transition of the nuclear spin on the magnitude of the nuclear energy. With its large-scale application in various aspects, people’s life was facilitated greatly. In the field of medication, as a new imaging technique, it has no negative effect on human health, and high-resolution image could be produced without any radiation. Millions of patients and injuries could get the correct diagnosis and lead a healthy life later on thanks to it.

A thin metallo-dielectric stacked metamaterial as “add-on” for magnetic field enhancement in clinical MRI

Magnetic resonance imaging (MRI) is a widely used clinical diagnostic tool, which is based on the principle of nuclear magnetic resonance of hydrogen atoms in human body. The Larmor frequency of precession of the hydrogen atoms is determined by the strength of static magnetic field ( B0) of MRI. A higher B0 can directly improve signal-to-noise ratio (SNR) of MRI. However, this method involves expensive hardware installation, which could have adverse effects of tissue-heating and make MRI unsafe for patients with medical implants. Hence, efforts have been made to increase the SNR of MRI without increasing B0. An effective solution in this direction would be to boost the radiofrequency (RF) magnetic fields emitted by the body part undergoing scan, particularly by using metamaterials. The higher the received RF signal strength, the greater the SNR of MRI. For a metamaterial to be used as an “add-on” in commercial scanners, its dimensions need to be designed appropriately so that it fits in the available gap between the transceiver coil and the human body. In this article, a 10-mm-thick metallo-dielectric metamaterial is designed by a stacking of alternate square-shaped capacitive patches and inductive apertures for enhancing the RF magnetic flux density and hence, the SNR of a 1.5 T MRI system. The inter-layer electromagnetic coupling in the stacked structure is deployed for spatial localization of magnetic fields at the resonant frequency (∼64 MHz) which is equal to the Larmor frequency of 1.5 T MRI. An equivalent circuit model, comprising a lumped-element third order bandpass filter, validated the transmissivity characteristics of the metamaterial obtained using full-wave simulations. Magnetic flux density enhancement by a factor of 55 is obtained when the metamaterial add-on is placed between a surface coil and a bio-model of human head.

Possibility of application nuclear magnetic resonance for measurement of fluid-flow

The paper considers the application of nuclear magnetic resonance for measurement of fluid-flow. The paper is of an experimental nature. Flowmeter based on nuclear magnetic resonance is extremely precise. The combined measurement uncertainty can be 0.1 %. Such a value of measurement uncertainty indicates that it is a matter of a deterministic and not of a stochastic quantity. This high degree of reliability of the method is theoretically and mathematically described. The paper presents a measurement scheme for flow measurement. Water flow measurement was performed on the principle of nuclear magnetic resonance and on the basis of tritiated water (which is considered to be the most accurate classical method). The obtained results show that the measurement of flow based on nuclear magnetic resonance is more accurate (especially at higher flow). This is explained by the higher inertial mass of HTO tritiated water molecules than the standard H2 O mass and the possible transition of tritiated water to H3HeO. In this way, it has been proven that tracing water based on nuclear magnetic resonance is the only real tracing of water by water. The obtained results show that tracing water with tritiated or heavy water is not tracing water by water which is explained by different inertial masses.

A Review of the Application of Nuclear Magnetic Resonance in Petroleum Industry

In the petroleum industry, Nuclear Magnetic Resonance (NMR) technology has been applied to numerous applications in the laboratory and for wireline logging, which provides vital information about the petrophysical properties of the reservoirs. The primary purpose of this paper is to evaluate the various applications of the Nuclear Magnetic Resonance technology presently used in conventional and unconventional reservoir systems for formation evaluation purposes in the petroleum industry. Additionally, to better comprehend the type of analysis and information that could be derived from the NMR measurement, a detailed literature review was conducted on the history, theory, and principles of nuclear magnetic resonance. This paper also discussed some standard methods in which NMR technology has been used in the oil and gas industry to estimate reservoir properties such as porosity, permeability, wettability, irreducible water saturation, and irreducible oil saturation. Likewise, it reveals that the borehole and laboratory applications of the NMR measurement have been utilized in both conventional and unconventional reservoir systems to quantify critical parameters like pore size distribution, porosity, and permeability. The application of NMR measurement also gives a better understanding of the interaction between fluids in the reservoirs and the rock properties. This review establishes that the exploration and production of oil in the industry have benefited from NMR technology by effectively enhancing the evaluation of formation and fluid properties in the reservoir.

On the quaternionic form of the Pauli–Schrödinger equation

A thorough approach to quantum mechanics should rely on an algebraic operation of multiplication based on proper algebraic structures, i.e. division algebras. Quaternions, with their commutation rules isomorphic to SU(2), offer such a framework. In this work, a quaternion algebraic approach derived from the finite groups is used to solve the spatially invariant time-dependent Pauli–Schrödinger equation and derive the Rabi formula and the principle of nuclear magnetic resonance and its generalization. The spatial and time-dependent Pauli–Schrödinger equation is then written using left-chirality quaternions, i.e. by expressing the Pauli spinor, its time derivative, and the Hamiltonian as elements of the same division algebra. The quaternion formalism is used to derive the dispersion relation of a free electron and of an electron in a constant magnetic field. Finally, the formalism is applied to calculate the transmission probabilities through a one-dimensional delta scatterer and through a resonant tunneling structure composed of two one-dimensional quaternionic delta-scatterers in series. The results are compared to the transmission probabilities calculated using traditional (complex) quantum mechanics.

Magnetic Resonance Imaging in Huntington's Disease.

Magnetic resonance imaging (MRI) is a noninvasive technique used routinely to image the body in both clinical and research settings. Through the manipulation of radio waves and static field gradients, MRI uses the principle of nuclear magnetic resonance to produce images with high spatial resolution, appropriate for the investigation of brain structure and function.

Localization of microscale devices invivo using addressable transmitters operated as magnetic spins.

The function of miniature wireless medical devices, such as capsule endoscopes, biosensors and drug-delivery systems, depends critically on their location inside the body. However, existing electromagnetic, acoustic and imaging-based methods for localizing and communicating with such devices suffer from limitations arising from physical tissue properties or from the performance of the imaging modality. Here, we embody the principles of nuclear magnetic resonance in a silicon integrated-circuit approach for microscale device localization. Analogous to the behaviour of nuclear spins, the engineered miniaturized radio frequency transmitters encode their location in space by shifting their output frequency in proportion to the local magnetic field; applied field gradients thus allow each device to be located precisely from its signal's frequency. The devices are integrated in circuits smaller than 0.7mm3 and manufactured through a standard complementary-metal-oxide-semiconductor process, and are capable of sub-millimetre localization invitro and invivo. The technology is inherently robust to tissue properties, scalable to multiple devices, and suitable for the development of microscale devices to monitor and treat disease.

Detecting the Oil Content in the Drilling Mud Based on Low Field Nuclear Magnetic Resonance

It is an very important link in the development of logging technology to establish relevant detection method for oil content in the drilling mud while drilling.Based on the principle of nuclear magnetic resonance(NMR), in this paper, the oil content of drilling mud which composed of gasoline,diesel oil and saltwater mud are tesed by NMR, and the relationship between the NMR parameters and the oil content in drilling mud is established.The experimental results show that the MRS of drilling mud sample cannot be obtained until the sationary time of the samples is more than a certain time (the best measurement time).; and there is a linear positive correlation relationship between the oil content in drilling mud and the oil peak ratio of the T2 spectrum, What is more, the slope of the linear relation varies with the oil types contained in the mud.

SnapShot: Biomolecular NMR

The essential principles of nuclear magnetic resonance for the analysis of biomolecules are conveyed in this SnapShot.

Principles of Nuclear Magnetic Resonance and Electron Spin Resonance.

Principles of Nuclear Magnetic Resonance and Electron Spin Resonance.

Efficient computer aided diagnosis of abnormal parts detection in magnetic resonance images using hybrid abnormality detection algorithm

AbstractIn Medical Diagnosis, Magnetic Resonance Image (MRI) plays a momentous role. MRI is based on the physical and chemical principles of Nuclear Magnetic Resonance (NMR), a technique used to gain information about the nature of molecules. Retrieving a high quality MR Image for a medical diagnosis is critical. So denoising of Magnetic Resonance (MR) images and making them easy for human understanding form is a challenge. This research work presents an efficient Hybrid Abnormal Detection Algorithm (HADA) to detect the abnormalities in any part of the human body by MRIs. The proposed technique includes five stages: Noise Reduction, Smoothing, Feature Extraction, Feature Reduction and Classification. The proposed algorithm has been implemented and Classification accuracy of 98.80% has been achieved. The result shows that the proposed technique is robust and effective compared to other recent works. The system developed using the proposed algorithm will be a good computer aided diagnosis and decision making system in healthcare.

Inclined Levitron experiments

An inclined Levitron demonstration serves to illustrate macroscopically the basic non-quantum mechanical principle of nuclear magnetic resonance. By tuning a “rotary driver” to either the precession or the nutation frequency, the levitated top is made to precess or nutate visibly. By reflecting the beam from a laser-pointer off the Levitron, cycloidal pictures of the induced motion are obtained. Steady inclination at a steep angle is demonstrated in contrast to rotating inclination. Levitron traps are analogous to particle traps. Inclined or horizontal axis operation could lead to nearly frictionless bearings.

Magnetic Nanoparticles in Magnetic Resonance Imaging and Diagnostics

Magnetic nanoparticles are useful as contrast agents for magnetic resonance imaging (MRI). Paramagnetic contrast agents have been used for a long time, but more recently superparamagnetic iron oxide nanoparticles (SPIOs) have been discovered to influence MRI contrast as well. In contrast to paramagnetic contrast agents, SPIOs can be functionalized and size-tailored in order to adapt to various kinds of soft tissues. Although both types of contrast agents have a inducible magnetization, their mechanisms of influence on spin-spin and spin-lattice relaxation of protons are different. A special emphasis on the basic magnetism of nanoparticles and their structures as well as on the principle of nuclear magnetic resonance is made. Examples of different contrast-enhanced magnetic resonance images are given. The potential use of magnetic nanoparticles as diagnostic tracers is explored. Additionally, SPIOs can be used in diagnostic magnetic resonance, since the spin relaxation time of water protons differs, whether magnetic nanoparticles are bound to a target or not.

New technologies in groundwater exploration. Surface Nuclear Magnetic Resonance

As groundwater becomes increasingly important for living and environment, techniques are asked for an improved exploration. The demand is not only to detect new groundwater resources but also to protect them. Geophysical techniques are the key to find groundwater. Combination of geophysical measurements with boreholes and borehole measurements help to describe groundwater systems and their dynamics. There are a number of geophysical techniques based on the principles of geoelectrics, electromagnetics, seismics, gravity and magnetics, which are used in exploration of geological structures in particular for the purpose of discovering georesources. The special geological setting of groundwater systems, i.e. structure and material, makes it necessary to adopt and modify existing geophysical techniques. A new discipline called hydrogeophysics has been formed and is growing fast. Efforts for direct detection of groundwater led recently to a new technique: Surface Nuclear Magnetic Resonance (SNMR). The principle of nuclear magnetic resonance, well known in physics, physical chemistry as well as in medicine, has successfully been adapted to assess the existence of groundwater and the aquifer parameters. This technique allows for the first time detecting and assessing water directly by only surface measurements allowing quantitative information about mobile water content as well as pore structure parameters leading to hydraulic conductivities. Function, results, interpretation, advantages and drawbacks of SNMR are reviewed in this paper showing the current state of art and developments. A comprehensive example of SNMR is presented with measurements conducted at the site of Nauen near Berlin. The site has Quaternary aquifers with differing layering of sand and till. The results are very satisfying as aquifers down to 50 m depth can be identified quite reliably. The water content is estimated with a high degree of accuracy and relaxation times allowed to derive hydraulic conductivities. Supplementary measurements with geoelectrics and radar made possible to complement and confirm the information achieved with SNMR as well as to apply a joint multimethod approach to aquifer assessment.

Time-symmetric quantum mechanics questioned and defended

The article by Yakir Aharonov, Sandu Popescu, and Jeff Tollaksen is stimulating and raises some interesting and profound issues regarding the foundations of quantum mechanics and quantum measurements. One point the authors make is that a measurement of spin component √2‾/2 of a spin-1⁄2 particle is unphysical and can be attributed only to errors in weak measurements performed on a collection of N spins. I offer a more mundane interpretation that does not require the introduction of any error or postselection concepts. The physical, textbook picture of spin-1⁄2 is a vector of length √S(S + 1) = √3‾/2 with some distribution of orientations (that is, polar coordinates θ and φ). A conventional single measurement of Sz can yield only one of the eigenvalues ±1⁄2. This may be interpreted in the classical vector model by envisioning that the spin lies on a cone with θ defined by cosθ = √3‾/3. The expectation value of Sx then vanishes due to the uniform distribution of φ. Having some control over φ can yield a finite value of Sx . Thus I would argue that only an expectation value greater than √3‾/2 is unphysical; a value of √2‾/2 is quite physical and can even be interpreted classically in terms of some distribution of φ and θ.I would phrase the important observation of Aharonov and coauthors in a different way. While spin-1⁄2 has a magnitude of √3‾/2, a fundamental limitation of conventional single-point quantum measurements is that they can yield only the values +1⁄2 and −1⁄2 and any expectation value must therefore lie between those two extremes. Classically, therefore, the spin may not be fully aligned along the z-axis with θ = 0. Such alignment is impossible since it would yield well-defined values of the three noncommuting variables Sz = √3‾/2 and Sx = Sy = 0. However, once multiple time measurements are performed, one can define a reduced distribution of some of the measurements that is conditional on the outcome in the other measurements; such a distribution can be interpreted in terms of Sz greater than 1⁄2 but less than or equal to √3‾/2. That interpretation does not violate any of quantum mechanics’ fundamental rules, which do not usually consider such quantities.Rather than a new, time-symmetric formulation of quantum mechanics that involves pre- and postselection, one can simply treat the scheme of the authors’ figure 1b as a three-point correlation function, whereas figures 2a and 2b show a four-point correlation function, each panel having its own set of conditional probabilities. Error, time reversal, and postselection need not be invoked. Instead, one may think in multiple dimensions and develop the right language for the interpretation of the observables.The combination of pre- and postselection is an attempt to create an artificial ensemble that reproduces the results of multiple-point measurements in a single one-point measurement. As shown by Aharonov and coauthors, that is possible by introducing errors. An alternative physical picture is obtained by retaining the multipoint analysis. Multidimensional thinking is well developed in coherent nonlinear spectroscopy, where a system of spins or optical chromophores are subjected to sequences of short impulsive pulses.11. R. R. Ernst G. Bodenhausen A. Wokaun Principles of Nuclear Magnetic Resonance in One and Two Dimensions Clarendon Press, New York (1978) . , 22. S. Mukamel Annual Review of Physical Chemistry 51 1 691 (2000). https://doi.org/10.1146/annurev.physchem.51.1.691 ; Physical Review A 61 2 21804 (2000). https://doi.org/10.1103/PhysRevA.61.021804 ; Principles of Nonlinear Optical Spectroscopy Oxford U. Press, New York (1995) . Similar ideas may be applied for the interpretation of multiple measurements. One can think of various types of n-point observables obtained by combining n − m perturbations and m measurements. The nonlinear n-point response functions in spectroscopy represent n − 1 impulsive perturbations followed by a single measurement. The objects Aharonov and colleagues considered correspond to n = m. Proper multiple-distribution functions could then be naturally used for the interpretation of such generalized measurements.REFERENCESSection:ChooseTop of pageREFERENCES <<1. R. R. Ernst G. Bodenhausen A. Wokaun Principles of Nuclear Magnetic Resonance in One and Two Dimensions Clarendon Press, New York (1978) . Google Scholar2. S. Mukamel Annual Review of Physical Chemistry 51 1 691 (2000). https://doi.org/10.1146/annurev.physchem.51.1.691 ; Google ScholarCrossref, ISI Physical Review A 61 2 21804 (2000). https://doi.org/10.1103/PhysRevA.61.021804 ; , Google ScholarCrossref, ISI Principles of Nonlinear Optical Spectroscopy Oxford U. Press, New York (1995) . , Google Scholar© 2011 American Institute of Physics.

Role of chelates in magnetic resonance imaging studies

Imaging studies are tests performed with a variety of techniques that produce pictures of the inside of a patient's body. Magnetic resonance imaging (MRI) is an imaging technique based on the principles of nuclear magnetic resonance. MRI uses a powerful magnetic field, radio waves, and a computer to produce detailed pictures of organs, soft tissues, bone, and virtually all other internal body structures. Chelates have a wide application in such imaging techniques. Chelates in imaging studies are used alone as radioactive agents or conjugated to monoclonal antibodies or to DNA as radioactive agents. Technetium chelates and gadolinium chelates are being widely used as magnetic resonance contrast media.

Testing the quality of magnetic gradient fields for studying self-diffusion processes by magnetic resonance methods

Imaging techniques based on the principle of nuclear magnetic resonance (NMR) rank with the most advanced methods for studying chemical and biological properties of substances. Their universality makes them particularly suitable for use in a wide range of scientific branches. NMR has found significant application in medicine. The diffusion effects of water molecules in tissues reduce the magnitude of spin echo in NMR measuring methods. Based on the amplitude change in the image, the diffusion coefficients and their distribution in the specimen being measured can be calculated. MR images of an object weighted by diffusion coefficients require a defined sequence of gradient pulses and accurate knowledge of their time behaviour. Methods for measuring the diffusion coefficients require knowledge of the minimum length of leading and trailing edges, the defined magnitude of the magnetic field gradient being excited and also the symmetry of positive and negative gradient pulses (the zero integral of pulses of the same magnitude with opposite polarity). To determine the above characteristics of the time behaviour of gradient pulses of both polarities a simple measuring method was developed and experimentally tested on a tomograph with 4.7 T induction of the basic magnetic field. This method is based on the principle of measuring the instantaneous frequency of the MR signal in the presence of a gradient pulse subsequent to exciting a thin defined layer of the specimen under examination outside the gradient field centre.

Stability of MRS signal and estimation of data quality

ABSTRACTBased on the principle of nuclear magnetic resonance (NMR), the magnetic resonance sounding (MRS) method is used to measure the magnetic resonance signal from groundwater via a surface loop. The accuracy of the measurements depends on both the stability of the magnetic resonance signal under varying experimental conditions (geomagnetic field, electromagnetic noise, etc.) and the accuracy of the measuring device. The efficiency of the signal processing algorithms adopted by the NUMISPlus device, as well as sensitivity to the signal‐to‐noise (S/N) ratio (), are numerically investigated. The results are shown to be stable when .Numerical simulation of the magnetic resonance signal shows that with a fluctuating geomagnetic field and within a few Hertz of the frequency offset, amplitude remains stable whereas phase follows the geomagnetic field variations. An anti‐correlation is observed between phase and frequency shift.The numerical results were validated experimentally using the NumisPlus system at St‐Cyr‐en‐Val near the city of Orleans, France. For filtered data with and a frequency offset within ±0.5 Hz, the relative standard deviation of the measurements was found to lie within ±12% for amplitude and ±10° for phase. The standard deviation of the signal, which is strongly weighted by the S/N ratio, is higher for lower pulses than for higher pulses. Analysis of the stability of the current transmitted by NumisPlus reveals that for weak currents (&lt;5 A), the standard deviation of the pulse amplitude is 3.7%, whereas for stronger currents (&gt;100 A), it is only 1.3%. We thus conclude that for currents greater than 5 A, the instrumental instability of NumisPlus is significantly less than the electromagnetic noise, which can be considered as the major source of error. The S/N ratio can be significantly improved by stacking, which is efficient but time consuming. Note that the accuracy of measurements carried out over a long time (due to stacking) may decrease as measuring conditions can change during any one sounding.The accuracy of the field measurements for enables the complex MRS signal to be used in the inversion process instead of only amplitude. Nevertheless, any variation in the geomagnetic field with time must be taken into consideration during inversion of the MRS signal.

The Structural Basis of Compstatin Activity Examined by Structure-Function-based Design of Peptide Analogs and NMR

We have previously identified compstatin, a 13-residue cyclic peptide, that inhibits complement activation by binding to C3 and preventing C3 cleavage to C3a and C3b. The structure of compstatin consists of a disulfide bridge and a type I beta-turn located at opposite sides to each other. The disulfide bridge is part of a hydrophobic cluster, and the beta-turn is part of a polar surface. We present the design of compstatin analogs in which we have introduced a series of perturbations in key structural elements of their parent peptide, compstatin. We have examined the consistency of the structures of the designed analogs compared with compstatin using NMR, and we have used the resulting structural information to make structure-complement inhibitory activity correlations. We propose the following. 1) Even in the absence of the disulfide bridge, a linear analog has a propensity for structure formation consistent with a turn of a 3(10)-helix or a beta-turn. 2) The type I beta-turn is a necessary but not a sufficient condition for activity. 3) Our substitutions outside the type I beta-turn of compstatin have altered the turn population but not the turn structure. 4) Flexibility of the beta-turn is essential for activity. 5) The type I beta-turn introduces reversibility and sufficiently separates the two sides of the peptide, whereas the disulfide bridge prevents the termini from drifting apart, thus aiding in the formation of the hydrophobic cluster. 6) The hydrophobic cluster at the linked termini is involved in binding to C3 and activity but alone is not sufficient for activity. 7) beta-Turn residues Gln(5) (Asn(5))-Asp(6)-Trp(7)(Phe(7))-Gly(8) are specific for the turn formation, but only Gln(5)(Asn(5))-Asp(6)-Trp(7)-Gly(8) residues are specific for activity. 8) Trp(7) is likely to be involved in direct interaction with C3, possibly through the formation of a hydrogen bond. Finally we propose a binding model for the C3-compstatin complex.