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Publisher: Springer-Verlag   (Total: 2345 journals)

 Applied Magnetic Resonance   [SJR: 0.358]   [H-I: 34]   [3 followers]  Follow         Hybrid journal (It can contain Open Access articles)    ISSN (Print) 1613-7507 - ISSN (Online) 0937-9347    Published by Springer-Verlag  [2345 journals]
• An Optimized Passive Shimming Method for Bi-planar Permanent MRI Magnets
• Authors: Zhonghua He; Wei He; Jiangqian Guo
Abstract: An optimized passive shimming method with iron shims is presented in this paper. First, the influence value of a single iron or magnetized shim is fast calculated and determined by analytic solution with a single practical measurement. Then, the correlation between the influence value and parameters of a single shim is analyzed, and the proper parameters, including the position, polarity, and size (radius and thickness), of the shimming pieces are well selected. Finally, the numbers and locations of the passive shims are optimized by mixed-integer linear programming method based on a modified central magnetic field. The optimized method is applied to a 0.5 T Bi-planar permanent magnet magnetic resonance imaging system, and the presented results prove the efficacy of this optimized passive shimming methodology.
PubDate: 2017-06-20
DOI: 10.1007/s00723-017-0908-7

• Reduction of Effect of Concomitant Gradients in Low Magnetic Field MRI via
• Authors: Vladimir Chizhik; Vyacheslav Frolov; Pavel Kupryanov; Konstantin Tyutyukin
Abstract: The effect of concomitant magnetic fields emerging in conjunction with encoding gradients, which is important in the process of the magnetic resonance imaging in low fields, has been considered. The manifestations of concomitant magnetic fields in a concrete gradient system, namely in the system of two coaxial gradient coils, have been thoroughly analyzed. It has been suggested to improve the gradient system via optimization of the interspace between coils on the basis of the standard criterion of the minimum of root-mean-square deviation of the encoding field dependence from a linear one. It has been shown that the optimal interspace is not the Maxwell condition.
PubDate: 2017-06-17
DOI: 10.1007/s00723-017-0909-6

• Single-Sequence Multi-Slice NMR in Strong Gradient Magnetic Fields
• Authors: Baosong Wu; Stephen A. Altobelli; Eiichi Fukushima
Abstract: We describe and apply a scheme to obtain nuclear magnetic resonance (NMR) signals from multiple regions in space with a single pulse sequence in systems with strong, usually unavoidable, gradient magnetic fields. This is accomplished with multiple frequency irradiation and reception. Applications described include dual-slice NMR of a fluid to enhance S/N, T 2 measurements of two different samples, and efficient T 1 measurement sequence by interleaving shorter delays within a longer delay for different slices.
PubDate: 2017-06-15
DOI: 10.1007/s00723-017-0899-4

• The 55 Mn Spin Echo Test of Magnon BEC State in MnCO 3
• Authors: Yu. M. Bunkov; A. V. Klochkov; T. R. Safin; K. R. Safiullin; M. S. Tagirov
Abstract: The coherent quantum state of magnons—Bose–Einstein condensate (BEC) has been observed in several types of antiferromagnets. According to the Bose statistics of magnons, BEC appears when the magnon density exceeds the critical density N BEC and the magnon gas condenses to a quantum liquid. The BEC state is characterized by a coherent precession of the magnetization. In this paper, the first experiments showing the suppression of the spin echo signal by the magnon BEC is presented. These experiments confirm the coherence of magnetic excitations in the BEC state.
PubDate: 2017-06-07
DOI: 10.1007/s00723-017-0906-9

• Diagnostic Value of Short and Long Echo Time in 1 H-MRS for Patients with
Multiple Sclerosis
• Authors: A. A. Bogdan; G. V. Kataeva; J. G. Khomenko; A. G. Ilves; L. N. Prakhova
Abstract: The quality of the signal received from metabolites in 1H-magnetic resonance spectroscopy (MRS) directly depends on physical parameters of the impulse sequence used, namely on Time of Echo (TE). We compare MRS (Achieva 3T PRESS 1H-MRS (TE = 53 and 144 ms, TR = 2000 ms) data acquired in supraventricular white matter and medial cortex at two various TE (53 and 144 ms) for patients with the multiple sclerosis (25 patients with the confirmed diagnosis of relapsing-remitting multiple sclerosis and 20 patients with the diagnosis of secondary progressive multiple sclerosis) and control group (21 healthy volunteers, comparable on age), to evaluate advantages and disadvantages of these two Echo Time in clinical practice.
PubDate: 2017-06-06
DOI: 10.1007/s00723-017-0900-2

• Trinuclear Gd(III) Metal Complex with Amide Core Display Remarkable
Enhancement in Relaxivity
• Authors: T. Lurthu Pushparaj; V. Alexander
Abstract: New trinuclear gadolinium(III) complex having 2-bromoisovaleric acid pendant arm is reported. The longitudinal relaxivity (r 1p) of the complex is 23.17 mM−1 s−1 which correspond to a “per Gd” relaxivity of 7.72 mM−1 s−1. The transverse relaxivity (r 2p) of the complex is 24.79 mM−1 s−1 which correspond to a “per Gd” value of 8.26. The complex exhibit r 1p and r 2p values of 29.19 and 35.20, respectively, in the presence of HSA. The complex also shows pH dependant relaxivity which is an added advantage of the complex for utilization in cancer cell magnetic resonance imaging. The higher relaxivity values in water and HSA indicates a compact solution structure for the complexes and a restricted internal motion about the amide spacer.
PubDate: 2017-06-06
DOI: 10.1007/s00723-017-0901-1

• A Pulse EPR 25 mT Magnetometer with 10 ppm Resolution
• Authors: Subramanian V. Sundramoorthy; Boris Epel; Howard J. Halpern
Abstract: A magnetometer designed for permanent magnet manufacturing and operated around 25 mT with 10 ppm absolute accuracy is described. The magnetometer uses pulse electron paramagnetic resonance methodology. The use of a pulsed broadband acquisition allowed reliable measurements in the presence of the magnetic field gradient and in relatively inhomogeneous magnetic fields of un-shimmed magnets.
PubDate: 2017-06-05
DOI: 10.1007/s00723-017-0902-0

• The Calcium Carbonate Geological Samples Study by 3 He NMR
• Authors: Egor Alakshin; Rasul Gazizulin; Alex Klochkov; Ekaterina Kondratyeva; Artem Laskin; Murat Tagirov
Abstract: Geological samples of calcium carbonates (CaCO3) were investigated by 3He NMR, nitrogen porosimetry, X-ray diffraction and electron microscopy methods. The integral porosity of the samples was obtained by 3He nuclear magnetic resonance method and compared with nitrogen adsorption isotherms data. The advantages of 3He porometry method are discussed.
PubDate: 2017-06-01
DOI: 10.1007/s00723-017-0904-y

• High-Field Electron Paramagnetic Resonance Reveals a Stable Glassy
Fraction up to Melting in Semicrystalline Poly(dimethylsiloxane)
• Authors: Carlo Andrea Massa; Silvia Pizzanelli; Vasile Bercu; Luca Pardi; Dino Leporini
Abstract: The reorientation of the guest 4-methoxy-TEMPO (spin probe) in the disordered fraction of semicrystalline poly(dimethylsiloxane) (PDMS) is investigated by high-field electron paramagnetic resonance (HF-EPR) at 190 and 285 GHz. Accurate numerical simulations of the HF-EPR lineshapes evidence that the reorientation times of the spin probes are distributed between the melting temperature $$T_{\rm m}$$ and $$T_{\rm m}$$ —30 K. The distribution exhibits, in addition to a broad component, a narrow component with low mobility up to the PDMS melting point. It is shown that the temperature dependence of the reorientation time of the spin probes with low mobility is the same of the spin probes in glassy PDMS. The result suggests that the low-mobility fraction is localized in the so-called rigid amorphous fraction.
PubDate: 2017-06-01
DOI: 10.1007/s00723-017-0903-z

• The Frequency Shifts of the Nuclear Magnetic Momenta Larmor Precession in
the Mixture of Two Noble Gases
• Authors: E. N. Popov; K. A. Barantsev; A. N. Litvinov; V. A. Reshetov; A. N. Shevchenko
Abstract: The dynamics of nuclear magnetization in the mixture of two noble gases with different gyromagnetic ratios of the nuclei is studied theoretically. The nuclear magnetization is induced by the radiofrequency electromagnetic radiation, which causes the nuclear magnetic resonance in both types of noble gases in the mixture. Frequency shifts of the nuclear magnetic resonance appeared due to an interaction between different types of the noble gases is analytically predicted. The specifics of these shifts are such that they cannot be compensated by means of the external magnetic field. The nature of the magnetic field distortion in the cell caused by the nuclear magnetization is also discussed.
PubDate: 2017-05-26
DOI: 10.1007/s00723-017-0896-7

• Electron Paramagnetic Resonance Investigations of ZnSe:Mn Nanocrystals
• Authors: D. S. Mazing; A. V. Nikiforova; A. S. Osinin; V. A. Moshnikov; Yu. V. Bogachev; S. M. Sukharzhevskii
Abstract: Colloidal nanocrystals of ZnSe doped with Mn2+ were synthesized in non-polar medium using hot-injection technique. Obtained samples were characterized by means of photoluminescence and absorption spectroscopies. To confirm the incorporation of Mn2+ impurity and to reveal its state and localization, electron paramagnetic resonance (EPR) spectroscopy was employed. As a result, EPR spectra were analyzed and hyperfine splitting constant and g-factor for Mn2+ dopant were determined.
PubDate: 2017-05-25
DOI: 10.1007/s00723-017-0898-5

• The Medical 1 H-MRS Analysis of Edible Vegetable Oils Rancidity: Focus on
the Saturated/Unsaturated Fatty Acids (Bond) Change
• Authors: Onseok Lee; Suk-Jun Lee; Seung-Man Yu
Abstract: The purpose of this study was to investigate the usefulness of medical magnetic resonance spectroscopy analysis methods for assessment of edible oil rancidity. The four edible oils including soybean oil, olive oil, grape seed oil, and sunflower oil were selected for evaluating rancidity (cooking counts/time, exposure time in air). The total lipid ((–CH2–) n /noise), total saturated fatty acid (TSFA), total unsaturated fatty acid (TUSFA), total unsaturated bond (TUSB), and polyunsaturated bond (PUSB) were quantified by separating each peak area of –CH3, (–CH2–) n , –CH2–C=C–CH2–, =C–CH2–C=, and –CH=CH– by –CH3 by 1H-magnetic resonance spectroscopy (MRS) analysis. The change in fatty acid (bond) according to the cooking counts/time increased for all fatty acids (bond) in soybean oil and grape seed oil. In olive oil, all fatty acids (bond) decreased overall, while sunflower oil showed a decrease in TSFA and PUSB and an increase in TUSFA and TUSB. The soybean, grape seed, and sunflower oils showed increased TUSB, TUSFAB, and PUSB with exposure to air after cooking once, while olive oil showed hardly any changes in fatty acids according to the exposure time to air after cooking. It will be necessary to choose a method that minimizes changes in fatty acids by fully understanding the characteristics of the selected edible oil to prevent not only a change in fatty acids during cooking, but also an increase in TSFA.
PubDate: 2017-05-16
DOI: 10.1007/s00723-017-0893-x

• Quantitative Effect of Magnetic Field Strength on PEGylated
Superparamagnetic Iron Oxide Nanoparticles
Abstract: With promising applications of superparamagnetic iron oxide nanoparticles (SPIO) in magnetic resonance imaging (MRI) and targeted monitoring of molecular and cellular processes, many different samples of these nanoparticles (NPs) with different compositions synthesized each year. The main challenge in this way is to generate enough contrast that could be traceable on images. In order to compensate for the low quantity of contrast agents in desired sites, surface engineering has to be done to enhance relaxation rates. As many factors such as magnetic field strength can affect relaxation rates of NPs, knowledge of the relation between field strength and relaxation rates is essential to compare results of different fields and choosing an optimum agent for a specific field. In this study, we evaluate the effects of magnetic field strengths of 0.35, 1.5, and 3 T on relaxation rates of PEGylated SPIOs. Longitudinal and transverse relaxation rates of all samples with various concentrations were analyzed quantitatively on appropriate spin–echo sequences. Our results suggest that the increasing of the field strength leads to a marked decrease of longitudinal relaxivity. In the case of transverse relaxivity, all NPs showed an increase between 0.35 and 1.5 T. Upon further increasing the field strength, relaxation rates only slightly increased except for two samples that showed saturation.
PubDate: 2017-05-15
DOI: 10.1007/s00723-017-0880-2

• ESR Study of Y 2 SiO 5 :Nd 143 Isotopically Pure Impurity Crystals for
Quantum Memory
• Authors: A. A. Sukhanov; V. F. Tarasov; R. M. Eremina; I. V. Yatsyk; R. F. Likerov; A. V. Shestakov; Yu. D. Zavartsev; A. I. Zagumennyi; S. A. Kutovoi
Abstract: Two Y2SiO5 single crystals doped with 0.001 at.% of the 143Nd3+ ion (sample I containing the only 28Si isotope) and (sample II with the natural abundance of silicon isotopes) were studied using magnetic resonance methods. The spin–spin and spin–lattice relaxation times were measured at 9.7 GHz between 4 and 10 K. It is established that three relaxation processes describe temperature dependences of the spin–lattice relaxation for both crystals. They are one-phonon, two-phonon Raman and two-phonon Orbach–Aminov relaxation processes. It is established that temperature dependence of spin–spin relaxation time differs for different hyperfine components of the electron paramagnetic resonance spectrum of neodymium ions and depends on the kind of the neodymium isotope (143Nd or 145Nd).
PubDate: 2017-05-10
DOI: 10.1007/s00723-017-0888-7

• The Effect of Hydroxynaphtazarin Derivatives on Decrease of Ischemic Area
After Damage Focal Cerebral Blood Circulation
• Abstract: 7-Ethyl-2,3-diglutathionyl-6-hydroxynaphthazarin (GluNaz, 1a) can be a protector of the rat brain under ischemia. The effect of hydroxynaphtazarin derivative 1a was estimated. The focal ischemia by occlusion of middle cerebral artery (MCAo) was used. Conjugate 1a kept life of more then 30% of rats after treatment. Studied compounds did not render additional changes of arterial pressure before and within 3 h after operation. The injection of 1a in a concentration exceeding a therapeutic dose more than by ten times did not lead to an increase in heart rate in intact animals. The behavioral reactions of rats after occlusion showed an increase of cognitive frustration. Like 7-ethyl-2,3,6-trihydroxynaphthazarin (Ech, 1b) (Russian Pat. RU 2266737, 1999 [3]), GluNaz reduced the region of cytotoxic edema in rat brain after treatment. The recovering effect of 1a begins to improve within 48 h and 1b—within 72 h. Magnetic resonance imaging allows a detailed dynamic study of the effect of the compounds in our model of an ischemic stroke. So, the conjugate 1a studied can be potential medicine for the treatment of ischemic injury of a brain.
PubDate: 2017-05-06
DOI: 10.1007/s00723-017-0887-8

• Investigation of Coherence Time of a Nitrogen-Vacancy Center in Diamond
Created by a Low-Energy Nitrogen Implantation
• Authors: Chathuranga Abeywardana; Zaili Peng; Laura C. Mugica; Edward Kleinsasser; Kai-Mei C. Fu; Susumu Takahashi
Abstract: A nitrogen-vacancy (NV) center in diamond has been investigated extensively because of its promising spin and optical properties for applications to nanoscale magnetic sensing and magnetic resonance of magnetic elements outside the diamond. For those applications, a long decoherence time and positioning of an NV center on the diamond surface are desired. Here, we report the creation of NV centers near the diamond surface using a 3 keV nitrogen implantation and the coherence property of the created NV center.
PubDate: 2017-04-25
DOI: 10.1007/s00723-017-0885-x

• Using Terahertz Waves to Identify the Presence of Goethite via
Antiferromagnetic Resonance
• Authors: S. G. Chou; P. E. Stutzman; V. Provenzano; R. D. McMichael; J. Surek; S. Wang; D. F. Plusquellic; E. J. Garboczi
Abstract: Virtually every corrosion detection method reports only the presence of a material phase that denotes probable corrosion, not its spectral signature. A signature specific to the type of iron oxide corrosion product would not only confirm the presence of corrosion but also provide insight into the environment of its formation. To identify the unique spectral signature of a commonly occurring corrosion product, goethite (α-FeOOH), we performed high-resolution terahertz (THz) absorption loss measurements on a polycrystalline mineral sample of goethite, scanning from 0.045 to 1.5 THz. We report two distinct temperature-dependent absorption peaks that extend from 4.2 to 425 K. By combining X-ray diffraction and magnetic characterization on this large crystallite-sized goethite sample, we derived a Neél transition temperature of 435 K, below which the sample is antiferromagnetic. We interpret these absorption peaks as magnon transitions of the antiferromagnetic resonances, allowing precise identification of goethite, a common iron corrosion product and geological mineral, via two terahertz absorption peaks over this temperature range. This measurement technique has the potential for detecting iron-bearing oxides originating from corrosion occurring underneath layers of polymeric products and other protective coatings that can be easily penetrated by electromagnetic waves with frequencies on the order of 1 THz. Furthermore, the combined X-ray and magnetic characterization of this sample, which had a large crystallite size, also improved the previously established relationship between the Néel transition temperature and the inverse mean crystallite dimension in the [111] direction. Our results provide end-case peaks which, compared with goethite samples of smaller crystallite size and purity, will enable the extension of this non-destructive evaluation technique to real corrosion applications.
PubDate: 2017-04-24
DOI: 10.1007/s00723-017-0884-y

• MRI Study of Liesegang Patterns: Mass Transport and Banded Inorganic
Phase Formation in Gel
• Authors: Nikola Klanicová; Aneta Malá; Ondřej Macíček; Josef Zeman; Zenon Starčuk
Abstract: A new non-optic method for the study of Liesegang patterns was tested. Liesegang patterns are periodically banded precipitates produced by the reaction–diffusion process, mostly occurring in geology. The Liesegang experiment (5.5 M NH4OH, gelatin matrix with 0.4 M MgSO4) was monitored using a 9.4 T magnetic resonance imaging (MRI) system, allowing the acquisition of sample images in any location and orientation without interfering with the process studied. The development of patterns in a gel matrix was observed for 7 days after starting the reaction. Qualitative data (T 2- and T 2*-weighted images) and quantitative T 2 maps were acquired. Preliminary experiments show that MRI is able to distinguish the regions between the precipitated bands and the structural changes in the gel matrix during the reaction. A damaged gel matrix was measured to reveal the effect of the initial reagent-gel contact area. MRI study of Liesegang patterns provides empirical data which can be used in theoretical model testing.
PubDate: 2017-04-20
DOI: 10.1007/s00723-017-0882-0

• Quantitative Susceptibility Mapping of the Substantia Nigra in
Parkinson’s Disease
• Authors: Xinxin Zhao; Hedi An; Tian Liu; Nan Shen; Binshi Bo; Zhuwei Zhang; Pengfei Weng; Meining Chen; Mengchao Pei; Yi Wang; Dongya Huang; Jianqi Li
Abstract: The purpose of this study was to evaluate the sensitivities of quantitative susceptibility mapping (QSM) and R2* mapping in clinical diagnoses of Parkinson’s disease (PD). QSM images and R2* maps from 29 patients with PD and 25 healthy controls were obtained on a clinical 3T magnetic resonance imaging (MRI) system using a three-dimensional multi-echo gradient-echo sequence. Two-tailed t tests and receiver operating characteristic curves analyses were applied to the mean values of QSM and R2* of the two groups. In the PD group, a two-tailed Pearson correlation analysis was used to investigate the correlations between MRI measures (susceptibility and R2* values) and the Unified Parkinson’s Disease Rating Scale-III (UPDRS-III) score. In the substantia nigra (SN), a significant difference between patients with PD and healthy controls was found on QSM (154.80 ± 43.36 vs. 127.50 ± 21.05 ppb, P = 0.006) but not on R2* mapping. The receiver operating characteristic curves showed that QSM was more sensitive than R2* mapping to distinguish PD patients from healthy controls, with areas under the curve equal to 0.68 and 0.51, respectively. The UPDRS-III motor scores did not correlate with mean susceptibility or R2* values in the PD group. In conclusion, QSM is a more accurate and sensitive method than R2* mapping to detect the pathologic changes in the SN of patients with PD.
PubDate: 2017-04-06
DOI: 10.1007/s00723-017-0877-x

• Floquet Hamiltonian and Entanglement in Spin Systems in Periodic Magnetic
Fields
• Authors: E. B. Fel’dman; D. E. Feldman; E. I. Kuznetsova
Abstract: We investigate entanglement in a two-spin system with the dipole–dipole interaction in the multi-pulse spin locking nuclear magnetic resonance (NMR) experiment. We discover a conflict between an exact solution and the standard approximation employing a time-independent effective Floquet Hamiltonian. While the exact solution shows nonzero entanglement in the system, the perturbative Floquet approach predicts that entanglement is absent. The failure of the Floquet method is explained by the multivaluedness of the Floquet Hamiltonian. Correct results can only be obtained with a proper choice of the branch of the Hamiltonian. The same issue is present in other applications of the Floquet theorem in the perturbation theory beyond NMR.
PubDate: 2017-04-05
DOI: 10.1007/s00723-017-0879-8

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