Low-dimensional organic conductors show a rich phase diagram, which has, despite all efforts, still some unexplored regions. Charge ordered phases present in many compounds of the \({\hbox {(TMTTF)}}_2X\) family are typically studied with their unique electronic properties in mind. An influence on the spin arrangement is, however, not expected at first glance. Here, we report temperature and angle

Chemical exchange saturation transfer (CEST) enables detection of molecules such as glycogen, whose concentrations are too low to impact the signal intensity of standard MR imaging. Detection of these molecules is achieved by selectively saturating a molecule of interest and by measuring the reduction in water signal due to saturation transfer. CEST effects are dependent on parameters such as CEST

Many-spin entanglement is investigated in one-dimensional zigzag chains, consisting of up to 12 spins 1/2, with nearest neighbor and next nearest neighbor interactions at high and low temperatures. We consider multiple quantum (MQ) nuclear magnetic resonance (NMR) dynamics. The second moment of the distribution of MQ coherences, which provides a lower bound on the quantum Fisher information, is calculated

The new magnetic system construction and the registration circuit of the nuclear magnetic resonance signal in the weak magnetic field are considered. The peculiarities of nuclear magnetic resonance signal registration with the application of modulation method in the weak field from the small volume of liquid medium (less than 0.3 ml) are determined. Taking into account these peculiarities in the new

The concentration dependences of the self-diffusion coefficients of water molecules in water solutions of a series of 1–1 electrolytes at different temperatures determined using nuclear magnetic resonance (NMR) with a magnetic field gradient are analyzed. The relevant results show that the hydration sign for Cs+, I−, Rb+, Br−, K+, and Cl− ions changes at temperatures characteristic for each ion. These

Four azoles of different chemical structure were intercalated into MoO3, V2O5, and WO3 oxides synthetized via polycondensation of corresponding oxo-acids under the solvothermal conditions. Structural and morphology peculiarities of these hybrid materials were characterized using X-ray and neutron diffraction, electron microscopy and EPR spectroscopy. The EPR measurements provided the evidence that

Increasing dynamics in solids featuring nuclei subjected to second-order quadrupolar interactions lead to central-transition spectra that undergo two consecutive line-shaped transitions. Conventional motional narrowing occurs when the molecular exchange rate is on the order of the strength of the dominant interaction. In a second step, the resulting intermediately narrowed spectra change further when

Modern technique of electron spin resonance (ESR) measurements and data analysis in strongly correlated metals, which allows finding the full set of spectroscopic parameters including oscillating magnetization, relaxation parameter (line width), and hyromagnetic ratio (g-factor), is described. Application of the considered method is illustrated by such examples as metallic systems CeB6, Mn1−xFexSi

In this feasibility study, we use finite element method simulations to compare superconductors (SC) coils and permanent magnets (PM) assemblies as main field source for a small-scale magnetic resonance imaging scanner. The motivation behind this investigation is that for certain tissues, e.g., knee ligament, diagnosis can be performed with equipment operating with relatively weak magnetic fields. It

The knowledge of the different physical mechanisms determining the relaxation of the magnetization is crucial to obtain reliable petrophysical parameters from NMR experiments. Some studies have focused on asymptotic mechanisms providing simple expressions for the relaxation rate in terms of parameters of the system. The main difficulties in solving this problem are related to the existence of intrinsic

New nitroxide biradicals 15NR6–C≡C–(p-C6H4)2–C≡C–14NR6 (B2) and 15NR6–C≡C–(p-C6H4)2–C≡C–15NR6 (B3), where R6 denotes 1-oxyl-2,2,6,6-tetramethyl–1,2,3,6-tetrahydropyridine ring, are synthesized and studied in liquid solutions by continuous-wave electron paramagnetic resonance (EPR) spectroscopy. Hyperfine interaction constants and exchange integrals are determined from the simulation and fitting of

Mexoryl SX (terephthalylidene-3,3′-dicamphor-10,10′-disulfonic acid, Ecamsule) is a water-soluble UV-A absorber. The near-IR phosphorescence spectrum of singlet oxygen generated by photosensitization with Mexoryl SX was not observed in air-saturated water. On the other hand, the time-resolved near-IR phosphorescence spectrum was observed in oxygen-saturated phosphate buffer (pH 7.4). The quantum yield

An 14N nuclear quadrupole resonance (NQR) spectroscopy method has been developed using the singular spectrum analysis (SSA) based on the principal components concept. For the first time, it was demonstrated that this method can be used as a low cost and non-destructive quantitative method for analyses of small amounts (< 100 mg) of nitrogen containing solids. NQR technique is closely related to nuclear

Ferromagnetic resonance (FMR) and SQUID-magnetization measurements were performed out to assess the potential of using the antiferromagnetic IrMn compound as an exchange-bias layer for the Heusler alloy layer \(\hbox {Co}_2\hbox {Cr}_{1-x}\hbox {Fe}_x\hbox {Al}_y\) in the superconducting spin valve structure. It was observed that the exchange-bias field for the Heusler alloy film deposited directly

Abstract The isotope effect H → D on diffusion in proton-exchange membrane Nafion 212 is investigated using 1H and 2H nuclear magnetic resonance (NMR) diffusometry in a static magnetic field gradient in the temperature range from 200 to 332 K for proton and from 245 to 332 K for deuteron transport. The diffusion coefficients of both isotopes have identical temperature dependence, while proton diffusion

Abstract The investigations of nuclear magnetic resonance (NMR) relaxation of protons in aqueous solution and 2% agar–agar gel in the presence of magnetic nanoparticles were performed. To identify the effect of magnetic nanoparticles on the contrast of magnetic resonance images, the dependences of the MR signal intensity on the parameters of the two pulse radio-frequency (RF) sequences (spin-echo,

Abstract The suggested approach allowed us to derive analytical expressions for modeling the shape of solid-echo signal and its time evolution for a system of three-spin groups with arbitrary constants of dipole–dipole interaction (DDI) in solids. Our method is based on the use of symmetry operations for spin exchange and spin flipping along the axis of initial polarization. Most useful seem to be

Abstract The results of the study of the spectral and relaxation parameters of 63.65Cu nuclear magnetic resonance (NMR) in a local field in natural samples of the semiconductor mineral chalcopyrite (CuFeS2), which is characterized by a strong interplay of magnetic and electronic properties, are presented. The main attention was paid to the determination of the mechanism of nuclear spin–lattice relaxation

Abstract Using NMR spectroscopy, the structure of the new products obtained in reaction of ninhydrin-derived azomethine ylide with cyclopropenes was established and conformational mobility was studied. Complete signal assignments in 1H and 13C spectra on base analysis of some homo- and heteronuclear correlation spectra were made, and qualitative comparison of the cross-peak intensities in the NOESY

A comparative experimental analysis by EPR spectroscopy of the intensity of nitric oxide (NO) production and the content of the copper in the tissues of olfactory bulb of the brain of male Wistar rats were performed after modeling of ischemic stroke and treatment with immediate intranasal injection of mesenchymal stem cells (MSCs). Brain ischemia was simulated by ligation at the level of bifurcation

Abstract One of the most important problems in achieving daily frequency instability \(\sigma _{y} < 5 \cdot 10^{{ - 14}}\) of on-board rubidium atomic clocks on absorption cell with working 87Rb atoms and mixture of buffer gases is realization of the TFS parameter — of temperature frequency shift \(\delta \nu \left( T \right)\) at the level of \(\ \le 3 \cdot 10^{{ - 12}} /\, {^\circ } {\text{C}}

Abstract Based on the method of two-dimensional (2D) nuclear magnetic resonance (NMR) relaxometry, a technique was developed for determining the joint distribution of the correlation time \( \tau_{c} \) and the Van Vleck second moments \( \Delta \omega^{2} \). The field of application is the study of slow molecular motions corresponding to the condition of the ratio of nuclear magnetic relaxation times

Abstract This study investigated the effect of proton substitution on the phase transitions of Li2RbH(SO4)2 crystals. In order to determine the effects on the molecular motions of Li2RbH(SO4)2 crystals, we compared nuclear magnetic resonance (NMR) relaxation measurements with those of LiRbSO4 crystals. The spin–lattice relaxation time of 87Rb shows similar trends in Li2RbH(SO4)2 and LiRbSO4 crystals

Abstract Nuclear magnetic resonance (NMR) log is a powerful tool to obtain porosity and oil saturation in reservoir evaluation. NMR echo inversion, however, may give poor information in the two parameters if the ratio of signal-to-noise is not so good. Combining NMR log and some conventional logs, such as GR log, sonic log, and density log, a novel inversion algorithm is developed in this research

Abstract The use of magnetic resonance imaging (MRI) for radiotherapy treatment planning (RTP) is increasing due to excellent tissue contrast and high-resolution images compared to other modalities. However, the issue of image inhomogeneity which affects tissue delineation and contrast during treatment planning needs to be resolved. This study is aimed to qualitatively observe image inhomogeneity in

Abstract Solid-state 29Si and 71Ga NMR was used to study the synthetic gallosilicate Na16Ga16Si24O80 ·16H2O (Ga–natrolite). It has been shown that Ga–natrolite contains mainly Si(GaO4)3(SiO4) and Si(GaO4)2(SiO4)2-structural units and has sufficiently ordered structure. Temperature dependence of the spin–lattice relaxation time T1 of 71Ga nuclei has also been studied using solid-state NMR. Spin–lattice

Abstract The low temperature (T < 5 K) electron spin resonance in topological Kondo insulator SmB6 is investigated. It is shown that spin relaxation time of the paramagnetic centers responsible for low temperature electron spin resonance in SmB6 is about ~ 10−8 s, which exceeds by five orders of magnitude the widely accepted spin and charge fluctuation time ~ 10−13 s in the homogeneous mixed valence

We have performed numerical simulations to evaluate responses of the magnetic moments of a single nanoparticle possessing uniaxial anisotropy and a planar nanoparticle lattice to excitation by a magnetic field pulse. The precession dynamics of magnetic moment for a wide range of the pulse parameters and the lattice anisotropy value has been studied. We have explored and analyzed periodic dependences

Velocity is one of the most important parameters to study in complex fluid flow systems. Magnetic resonance imaging (MRI) is a non-invasive tool for quantitative visualization of fast fluid flows. Many of the flow studies by MRI measure the velocity of a fluid media using either phase encoding or time of flight (TOF) measurements. Until now, motion-sensitized SPRITE is the best method for the velocity

Total cerebral volume increases very rapidly in childhood, peaking in early teenage years then declining in adolescence. However, most studies quantified only one or few structures and the relative development pattern of subcortical structures is still unclear. For our study, we aim to examine the cortical, subcortical and structural changes associated with age by comparing the cortical and subcortical

Nuclear magnetic resonance (NMR) is a powerful technique for determining the petrophysical properties (porosity, permeability, and fluid mobility) of subsurface reservoirs through well logs, laboratory core analysis, or surface measurements of drill cuttings at the rig site. In well logging, NMR is considered a lithology-independent tool, but in surface measurements, it is possible to determine the

Characterizing the photosystem II (PSII) sample, continuous wave electron paramagnetic resonance (CW-EPR) simulations of the S2 ML signal at X-band frequencies was our focus. This can help increase our understanding of how the manganese (Mn) atoms in the catalytic site of the PSII magnetically interact using ML signals. It can also be used to further the understanding of possible water-splitting mechanisms

In the gradient coil optimization process, a dense linear system usually needs to be solved. When the mesh discretization method is used, the matrix will be very large, which makes direct methods very inefficient. The solution of the linear system is discussed in this paper for the optimization of gradient coils with the finite element method. Finally, a transversal planar gradient coil is designed

In this paper, a new, fast compressively sensed diffusion magnetic resonance image enhancement technique is presented. This algorithm aims to overcome two major obstacles—image resolution limitation and algorithm reconstruction time efficiency-by combining a highly sparse k–q-space sampling pattern with super-resolution (SR) image enhancement. Similar to the RoSA (rotating single-shot acquisition)

Radiation defects in quartz are widely used in trapped charge chronometry. Analytical function which simulates dose–response curve is a very important for the correct measurement of equivalent dose. Ge- and Ti-related centers in quartz which may be used in electron paramagnetic resonance (EPR) dating have non-monotonic dose–response curves. In addition to accumulation, very significant parameter of

Theoretical results are presented, which have been confirmed experimentally and became basis for a new paradigm of spin exchange between paramagnetic particles in solutions and measurement of the spin exchange rate by EPR spectroscopy. Fundamental changes in the basics of spin exchange in solutions are associated with the transfer of coherence back from the interaction partner. It was shown that the

An electron-spin resonance technique has been used to examine the influence exerted by the degree of compensation on spin effects in a set of nonmagnetic Ge:As semiconductor samples in the vicinity of the insulator–metal phase transition at temperatures 2 K ≤ T ≤ 80 K. It was found that the behavior of the paramagnetic susceptibility, specific to the Pauli paramagnetism and manifested in the spin density

A versatile, modular in situ high-intensity monochromatic illumination set-up installed on a standard Q-band ESR spectrometer equipped with a cryostat and probe head for measurements at cryogenic temperatures, which can be easily assembled from commercially available optical components is presented. Using as monochromatic light sources pig-tailed laser diodes (LDs) or fiber-coupled light-emitting diodes

Saturation-transfer difference (STD)-NMR spectroscopy has been widely used to screen potential ligands for binding to large receptor molecules. The STD-NMR experiment is typically based on a proton NMR spectrum, which can suffer from spectral overlap, leading to missing information in STD-based epitope mapping. Two-dimensional STD-NMR experiments can alleviate spectral overlap, but are time consuming

This paper describes an adjustable method for body composition analysis of awake mice based on time domain nuclear magnetic resonance (TD-NMR) technology. A T1-weighted CPMG pulse sequence was introduced to acquire the NMR signals that contain both longitudinal (T1) and transversal (T2) relaxation information of mice. It took less than 90 s to dramatically lighten the burden on animals. A model training

One of the promising areas in MRI diagnostics is the mapping of the distribution of nuclei other than 1H. It is caused by the presence of such nuclei in molecules involved in important biological processes. The spatial distribution of these nuclei in a body can be judged on those or other pathological processes occurring in it. One of such nuclei is 31P, which plays an important role in a living organism

The stretched exponential function (SEF) was used to analyze and interpret saturation recovery (SR) electron paramagnetic resonance (EPR) data obtained from spin-labeled porcine eye-lens membranes. This function has two fitting parameters: the characteristic spin-lattice relaxation rate (T 1str -1) and the stretching parameter (β), which ranges between zero and one. When β = 1, the function is a single

Site-directed spin labeling of proteins by chemical modification of engineered cysteine residues with the molecule MTSSL (1-Oxyl-2,2,5,5-tetramethylpyrroline-3-methyl methanethiosulfonate) has been an invaluable tool for conducting double electron electron resonance (DEER) spectroscopy experiments. However, this method is generally limited to recombinant proteins with a limited number of reactive Cys

A 25 mm diameter 250 MHz crossed-loop resonator was designed for rapid scan electron paramagnetic resonance imaging. It has a saddle coil for the driven resonator and a fine wire, loop gap resonator for the sample resonator. There is good separation of E and B fields and high isolation between the two resonators, permitting a wide range of sample types to be measured. Applications to imaging of nitroxide

In this study a specialized high-temperature nuclear magnetic resonance (NMR) setup is presented for measuring free moisture in monolithic refractory castables during one-sided heating (100-300 °C). This setup makes use of a high thermal-stability Birdcage-coil for measuring the quantitative moisture content at high-temperatures, while also utilizing a mini-coil for calibrating transverse relaxation

The papers, book chapters, reviews, and patents by James S. Hyde in the bibliography of this document have been separated into EPR and MRI sections, and within each section by topics. Within each topic, publications are listed chronologically. A brief summary is provided for each patent listed. A few publications and patents that do not fit this schema have been omitted. This list of publications is

Unique combination of ionic conductivity and anisotropic physical properties in ionic liquid crystals leads to new dynamic properties exploited in modern technological applications. Structural and dynamics information at atomic level for molecules and ions in mesophases can be obtained by nuclear magnetic resonance (NMR) spectroscopy through the measurements of dipole-dipole spin couplings. While 13C-1H

The potentials of the magnetic resonance (MR) methods in the research of biomedical systems have been demonstrated during the 70 years of its existence. It is presented that the Cuban experience in quantitative magnetic resonance associated with molecular, preclinical and clinical studies of significant diseases and drugs development. MR "in vitro" and "in vivo" studies of sickle cell disease, the

The presence of integral membrane proteins induces the formation of distinct domains in the lipid bilayer portion of biological membranes. Qualitative application of both continuous wave (CW) and saturation recovery (SR) electron paramagnetic resonance (EPR) spin-labeling methods allowed discrimination of the bulk, boundary, and trapped lipid domains. A recently developed method, which is based on

The electron spin resonance (ESR) of conduction electrons is reported for the weak itinerant ferromagnet Sc[Formula: see text]In which, upon chemical substitution with Lu, shows a suppression of ferromagnetic correlations. A well-defined ESR lineshape of Dysonian type characterizes the spectra. The ESR linewidth, determined by the spin dynamics, displays a broad minimum only for the Sc[Formula: see

Recently, a number of MRI protocols have been reported that seek to exploit the effect of dissolved oxygen (O2, paramagnetic) on the longitudinal 1H relaxation of tissue water, thus providing image contrast related to tissue oxygen content. However, tissue water relaxation is dependent on a number of mechanisms, and this raises the issue of how best to model the relaxation data. This problem, the model

We provide a detailed evaluation of nuclear magnetic resonance (NMR) parameters of the cis- and trans-isomers of azobenzene (AB). For determining the NMR parameters, such as proton-proton and proton-nitrogen J-couplings and chemical shifts, we compared NMR spectra of three different isotopomers of AB: the doubly 15N labeled azobenzene, 15N,15N'-AB, and two partially deuterated AB isotopomers with a

We developed an approach for determining distances between carbon nanoparticles and grafted paramagnetic ions and molecules by means of nuclear spin-lattice relaxation data. The approach was applied to copper-, cobalt- and gadolinium-grafted nanodiamonds, iron-grafted graphenes, manganese-grafted graphene oxide and activated carbon fibers that adsorb paramagnetic oxygen molecules. Our findings show

Average carbon chain length is a key parameter that defines the quality of liquid biofuels. In this paper, a method for the determination of carbon chain lengths of fatty acid mixtures is presented. The approach is based on proton relaxation rates measured by time domain nuclear magnetic resonance. The spin-spin relaxation rates R2 were used for the estimation of the carbon chain lengths. The method

Resonators for preclinical electron paramagnetic resonance imaging have been designed primarily for rodents and rabbits and have internal diameters between 16 and 51 mm. Lumped circuit resonators include loop-gap, Alderman-Grant, and saddle coil topologies and surface coils. Bimodal resonators are useful for isolating the detected signal from incident power and reducing dead time in pulse experiments

Calibrations are given to extract orientation order parameters from pseudo-powder electron paramagnetic resonance line shapes of 14N-nitroxide spin labels undergoing slow rotational diffusion. The nitroxide z-axis is assumed parallel to the long molecular axis. Stochastic-Liouville simulations of slow-motion 9.4-GHz spectra for molecular ordering with a Maier-Saupe orientation potential reveal a linear

The use of pressure is an advantageous approach to the study of protein structure and dynamics because it can shift the equilibrium populations of protein conformations toward higher energy states that are not of sufficient population to be observable at atmospheric pressure. Recently, the Hubbell group at the University of California, Los Angeles, reintroduced the application of high pressure to the

The dielectric tube resonator (DTR) for EPR spectroscopy is introduced. It is defined as a metallic cylindrical TE011 microwave cavity that contains a dielectric tube centered on the axis of the cylinder. Contour plots of dimensions of the metallic cylinder to achieve resonance at 9.5 GHz are shown for quartz, sapphire, and rutile tubes as a function of wall thickness and average radius. These contour

A copper X-band (9.22 GHz) cross loop resonator has been constructed for use with 4 mm sample tubes. The Q for the two resonators are 380 and 350, respectively. The resonator efficiency is about 1 G per square root of watt. Operation has been demonstrated with measurement of T1 by saturation recovery for samples of coal and an immobilized nitroxide radical.

A magnetometer designed for permanent magnet manufacturing and operated around 25 mT with 10ppm absolute accuracy is described. The magnetometer uses pulse electron paramagnetic resonance (EPR) 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.