Dynamics of spin dimers in multiple quantum NMR experiment is studied on the 5-qubit superconducting quantum processor of IBM Quantum Experience for the both pure ground and thermodynamic equilibrium (mixed) initial states. The work can be considered as a first step towards an application of quantum computers to solving problems of magnetic resonance. This article is dedicated to Prof. Klaus Möbius

Magnetic resonance imaging (MRI) system is used as one of the most common methods to read out the response of polymer gel dosimeters. The imaging protocols can have a remarkable effect on the response of polymer gel dosimeters; hence, the impact of imaging parameters on the response of each type of polymer gel dosimeter should be addressed. This study aims to investigate the effect of MRI parameters

Due to fast relaxation processes of transition metal ions, electron paramagnetic resonance (EPR) spectroscopy of metalloproteins needs to be performed at cryogenic temperatures. To avoid damaging the biological system upon freezing, a cryoprotectant is generally added to the sample as a glassing agent. Even though cryoprotectants are expected to be inert substances, evidences in literature show their

A selective heterogeneous catalyst with the superoxide anion O2•− stable at room temperature, generated by treating Ti(OR)4 (R = iPr, nBu) with H2O2, was previously reported and used for the oxidation of organic compounds. It was proposed that exceptional stability of the O2•− is resulted from its stabilization near Ti+4 cation on the TiO2 surface with the participation of water molecules and/or OH

The low signal-to-noise ratio is a characteristic feature of NMR experiments in the Earth’s magnetic field. The main problem of such studies is the ineffectiveness of signal accumulation due to fluctuations of the Earth’s magnetic field because of magnetic interferences from laboratory equipment and other magnetic field sources. Taking into account the fact that generally in the Earth’s magnetic field

The role of membrane cholesterol in cellular function and dysfunction has been the subject of much inquiry. A few studies have suggested that cholesterol may slow oxygen diffusive transport, altering membrane physical properties and reducing oxygen permeability. The primary experimental technique used in recent years to study membrane oxygen transport is saturation-recovery electron paramagnetic resonance

In this work, we investigated the redox transients of a number of water-soluble spin labels upon their interactions with Photosystem II (PS II) core complexes isolated from spinach leaves. We have found that the reactivity of nitroxide radicals, determined by the rate of their reduction upon illumination of PS II, depends on the chemical structure of radicals and the capability of their coming close

A new method for the resolution and quantitative kinetic analysis of overlapping electron paramagnetic (EPR) spectra, based on a combination of smoothing by B-splines and/or discrete cosine transformation and linear algebra methods for finding eigenvalues and eigenvectors of the covariance matrix using the Frobenius normal form with subsequent final basis adjustment by the Moore–Penrose pseudo-inverse

Testing and calibrating an experimental setup with standard samples is an essential aspect of scientific research. Single crystals of pentacene in p-terphenyl are widely used for this purpose in transient electron paramagnetic resonance (EPR) spectroscopy. However, this sample is not without downsides: the crystals need to be grown and the EPR transitions only appear at particular orientations of the

A comparative experimental analysis of intensity of nitric oxide (NO) production and the copper content in the tissues of hippocampus of male Wistar rats after modeling of hemorrhagic stroke and brain injury was conducted using EPR spectroscopy. Modeling of hemorrhagic stroke was carried out by microinjection of 500 nl of autologous blood into the brain to a depth of 5.0 mm (hippocampus) on the left

The photo-excited triplet state of Zn-protoporphyrin IX located in the heme pocket of human neuroglobin has been investigated by time-resolved EPR coupled to magnetophotoselection. The triplet state in the protein matrix has been compared with the model complex in organic glass, considering both non-coordinating and coordinating solvent mixtures. The protein matrix plays an important role in stabilizing

The article is devoted to the study of quantization of magnons in yttrium iron garnet film in the magnetic field gradient. Detected energy levels correspond to the quantization of particles in triangular potential. These energy levels are not equidistant. Therefore, they can be used to create a magnon quantum qubits.

\(^1\)H ENDOR spectra of tyrosyl radicals (Y\(^\bullet\)) have been the subject of numerous EPR spectroscopic studies due to their importance in biology. Nevertheless, assignment of all internal \(^1\)H hyperfine couplings has been challenging because of substantial spectral overlap. Recently, using 263 GHz ENDOR in conjunction with statistical analysis, we could identify the signature of the H\(^{\upbeta

Compressed sensing magnetic resonance imaging (CS-MRI) has been a widely studied field in biomedical signal processing owing to its success and practical MR machines integrated with the technology already rolling on in market. Since then, a decade-long research in the field has paved its way into deep-learning techniques being incorporated into the field to simplify some of the complex, theoretical

Large-scale triage after major radiological events, such as nuclear reactor accidents, requires a method of ionizing radiation dose estimation called retrospective biodosimetry (RBD) to detect doses in the range of 0.5–8 Gy. A well-known technique for performing RBD is electron spin resonance (ESR), which can be used to measure radiation-induced paramagnetic defects in the enamel of the teeth. The

Methano[60]fullerenes with two and four nitroxide radicals are studied by EPR spectroscopy. It is shown that nitroxide derivatives of fullerene C60 undergo conformational changes in liquid solution. It is established that transitions between the two conformations take place in the case of the biradical adduct of C60 fullerene. For the tetraradical adduct in the trans-3 position, it is shown that the

Nuclear quadrupole resonance (NQR) spectroscopy is used to identify narcotics and explosive materials. Detection of NQR signal generated by \({14}^{{N}}\) isotope in an open environment is a challenging task due to the presence of external random noise and RF interference. Unlike the existing wavelet-based and other frequency-domain approaches that use averaged data, the present work exploits raw data

Here, we report on a robust and efficient mechanism for tuning the microwave coupling of a Q-band (34 GHz), general purpose, cylindrical EPR cavity operating in the TE011 mode. This novel mechanism allows for both the adjustment of the cavity’s coupling over a wide frequency range, as well as its bandwidth from that of a high-Q cavity (about 10 MHz), to a broadband cavity (above 1 GHz). The coupling

This review is motivated by the exciting new area of radiation therapy using a phenomenon termed FLASH in which oxygen is thought to have a central role. Well-established principles of radiation biology and physics suggest that if oxygen has a strong role, it should be the level at the DNA. The key aspect discussed is the rate of oxygen diffusion. If oxygen freely diffuses into cells and rapidly equilibrates

In the present paper, we applied 63,65Cu NMR in a local field and EPR methods to study a series of Cu1-XPdXFeS2 (x = 0–0.02) compounds. These compounds have the structure of widespread chalcopyrite and attract interest due to their thermoelectric properties. To improve its thermoelectric performance, most research efforts have been focused on the optimization of the properties of CuFeS2 by proper doping

The mechanism of spin polarization transfer from a photogenerated spin-correlated radical pair to a stable radical was studied in a covalent donor-chromophore-acceptor-stable radical (D-C-A-R•) system, where the donor (D) is 4-methoxyaniline (MeOAn), the chromophore (C) is 4-(N-piperidinyl)-naphthalene-1,8-dicarboximide (ANI), the acceptor (A) is naphthalene-1,8:4,5-bis(dicarboximide) (NDI) and the

This article reviews the current status and challenges of using RF/microwave resonators for electron paramagnetic resonance (EPR) spectroscopy and imaging from the viewpoint of preclinical and clinical applications. In this review, resonator developments are summarized in the contexts of preclinical oximetry and free radical measurements in small rodents, clinical (human) oximetry, and human dosimetry

In the high-frequency ENDOR experiments, the hyperfine (HF) interaction between the unpaired electron of the shallow donor or shallow acceptor and the nuclear spins of the Coulombic center and the surrounding atoms is determined, which is then translated into the spin density of the electronic wave function at the various atomic positions. The results of studying the spatial distribution of wave functions

A perchlorotriarylmethyl tricarboxylic acid radical 99% enriched in 13C at the central carbon (13C1-PTMTC) was characterized in phosphate-buffered saline solution (pH = 7.2) (PBS) at ambient temperature. Samples immobilized in 1:1 PBS:glycerol or in 9:1 trehalose:sucrose were studied as a function of temperature. Isotope enrichment at C1 creates a trityl that can be used to accurately measure microscopic

Owing to their importance, diversity and abundance of generated paramagnetic species, radical S-adenosylmethionine (rSAM) enzymes have become popular targets for electron paramagnetic resonance (EPR) spectroscopic studies. In contrast to prototypic single-domain and thus single-[4Fe–4S]-containing rSAM enzymes, there is a large subfamily of rSAM enzymes with multiple domains and one or two additional

There is a strong need to enable accurate and convenient oxygen measurements in vivo for human subjects to improve treatments for cancer, peripheral vascular disease, and other diseases where tissue oxygen levels have a significant impact. While EPR spectroscopy has the potential to do this effectively, the full exploitation of these capabilities requires optimization of resonators for use with human

Oxygen sensing with light has been developing for many decades using injectable molecules called Oxyphors, which are pegylated, dendrimer-encapsulated metalloporphyrins that have a phosphorescence emission lifetime that is a direct reporter of the local oxygen partial pressure (pO2). In recent years, the ability to image this emission from tissue with Cherenkov light excitation during high-energy X-ray-based

EPR spectrometers (and various sub-systems) have been designed and constructed to facilitate in vivo measurements with human subjects for dosimetry and oximetry. Most applications are primarily focused on surface tissue measurements; however, oximetric measurements utilizing implantable devices are also discussed. Given various specifications and considerations across these two primary applications

Electron Paramagnetic Resonance (NMR) and Nuclear Magnetic Resonance (NMR) discovered around the middle of the twentieth century became two of the fastest evolving spectroscopic techniques with applications starting in physics and slowly developing into playing important roles in structural organic chemistry, biology, solid state, medicine, and almost any field. NMR has been developing relatively faster

Electron paramagnetic resonance oxygen imaging, EPROI, is established as a method for quantitative oxygen imaging. For tissue identification, in vivo oxygen images need to be paired with higher tissue contrast images such as MRI, CT, or ultrasound. All these images are acquired using different instruments and a method to represent them in a common coordinate frame, image registration, is required.

Factors that impact the need for and the effectiveness of blood transfusions depend on the recipient’s physiologic tolerance to acute anemia and the quality of the donor units that they receive. To date, indirect methods are used to determine the needs for blood transfusions and their efficacy in both clinical research and patient care settings. Methods that provide clear information on oxygen levels

Quantum state control is one of the most important concepts in advanced quantum technology, emerging quantum cybernetics and related fields. Molecular open shell entities can be a testing ground for implementing quantum control technology enabling us to manipulate molecular spin quantum bits (molecular spin qubits). In well-designed molecular spins consisting of unpaired electron and nuclear spins

The inversion of nuclear magnetic resonance (NMR) relaxometry data based on the first kind of Fredholm equation is an ill-posed problem. The accurate transverse relaxation time (T2) distribution is of great significance to improve the application of NMR. The T2 distribution from the norm smoothing method for low signal-to-noise ratio (SNR) data is inaccurate owing to a large penalty term of the objective

The effects of the temperature on the multi-exponential transverse relaxation signal of fruit tissues were studied by MRI at 1.5 T, with tomato as an example of fleshy fruits. The relative importance of chemical exchange mechanisms was investigated by comparing the results obtained from tomatoes with those obtained from aqueous solutions made up to simulate the vacuolar water pool. A more extended

The presented data clearly demonstrate that multinuclear MRI has a great potential in research and clinical fields. The biomedical value of many heavy nuclei that are part of drugs, contrast agents, and molecular complexes in live tissues emphasizes the need for creating and using MRI scanners tuned to the Larmor frequencies of such nuclei. This article discusses a number of specific problems solved

We have developed a pressure calibration method in the high-pressure THz ESR system using induction coils set outside the pressure cell. The pressure is calibrated using alternating current (AC) magnetization measurements of the superconducting transition temperature of tin set inside the pressure cell with an ESR sample. The system fits the developed pressure cell with a wide frequency range of 0

Kinetics of radical-ion pairs (RIPs) formed by photoinduced electron transfer in solution, as well as triplet and singlet products of their recombination, are studied within a general theory of spin-selective charge transfer assisted by diffusion of reactants in solution. The RIPs are assumed to be created in the singlet state, and their coherent singlet–triplet evolution is described in terms of isotropic

The light-gated dimeric cation channel channelrhodopsin-2 (ChR2) has been established as one of the most important optogenetic tools. During its functional cycle, ChR2 undergoes conformational changes, the most prominent ones include a movement of transmembrane helix B. In the present work, we assign this movement to a trapped photocycle intermediate using DEER spectroscopy combined with sample illumination

Paramagnetic centers (PCs) of Ti3+ and Cr3+ were detected in polycrystalline Cr-doped TiO2 (rutile) semiconductors in which the chromium content varied from 0.1 to 1.7 at.%. For the first time, the energy position of the Cr3+ ion in the band gap of such oxide semiconductors was determined using the electron paramagnetic resonance (EPR) technique with illumination in situ. The irradiation effect was

The gallium–indium eutectic alloy is in a focus of modern studies because of its great potential for microelectronics, wearable electronics, electronic skin, medical diagnosis, and soft robotics. Novel applications of the Ga–In alloy require better understanding of the effect of size reduction on its properties. Here we report the NMR studies of the nanostructured Ga–In alloy within pores of the opal

The formation mechanism of nanostructured polyaniline (PANI) synthesized in a micelle-like system was studied by a series of in situ NMR experiments, including 1H NMR and CPMG. Depending on the signal evolution of the major species, the polymerization of polyaniline was divided into three continuous stages. At first, the neutral aniline molecules changed into anilinium, and the aniline dimer produced;

A correction to this paper has been published: https://doi.org/10.1007/s00723-021-01359-6

Immature and chaotic vascular networks with critically increased intervascular distances are characteristic features of malignant tumors. Spatial and temporal heterogeneities of blood flow and associated availabilities of O2, together with limited diffusive O2 transport, and -in some patients- anemia, obligatorily lead to tumor hypoxia (= critically reduced O2 levels) on macro- and microscopic scales

Double electron–electron resonance (DEER, also known as PELDOR) is an efficient tool to study nanoscale distances between paramagnetic species forming oligomers or arranged in clusters. DEER also may be applied to study heterogeneous systems in which large clusters of spin labels may be considered as randomly distributed species of enhanced local concentration. For these systems, information of the

CW saturation experiments are widely used in ESR studies of relaxation processes in proteins and lipids. We develop the theory of saturation in ESR spectra in terms of its close relation with that of 2D-ELDOR. Our treatment of saturation is then based on the microscopic order macroscopic disorder (MOMD) model and can be used to fit the full CW saturation spectrum, rather than fitting just the peak–peak

EPR can uniquely measure paramagnetic species. Although commercial EPR was introduced in 1950s, the early studies were mostly restricted to chemicals in solution or cellular experiments using X-band EPR equipment. Due to its limited penetration (< 1 mm), experiments with living animals were almost impossible. To overcome these difficulties, Swartz group, along with several other leaders in field, pioneered

In this study, a recently proposed NMR standardization approach by 2H integral of deuterated solvent for quantitative multicomponent analysis of complex mixtures is presented. As a proof of principle, the existing NMR routine for the analysis of Aloe vera products was modified. Instead of using absolute integrals of targeted compounds and internal standard (nicotinamide) from 1H-NMR spectra, quantification

In this work we demonstrate the possibility to transfer parahydrogen-derived 1H polarization to 13C nuclei in the gas phase using PH-INEPT-based pulse sequences. The propane with hyperpolarized 1H nuclei was produced via hydrogenation of propylene (at natural 13C abundance) with parahydrogen over the heterogeneous 1 wt% Rh/TiO2 catalyst at 7.05 T magnetic field of a NMR spectrometer. The apparent proton

Coherence between tunnel-split states of a methyl quantum rotor can be generated and observed in stimulated and spin-locked echo experiments, if hyperfine coupling of a nearby electron spin to the methyl protons breaks C\(_3\) symmetry and is of the same order of magnitude as the tunnel splitting. Here, we consider the case of two methyl groups bound to the same sp\(^{3}\)-hybridized atom, which is

Spin polarized transient EPR spectra are reported for an aluminum(III) porphyrin (AlPorF3) triad in which the electron donor bis-triphenylaminoborondipyrromethene (BDP-TPA2) is attached covalently to one face of the porphyrin and an imidazole-appended C60 is attached by coordination of the imidazole group to the Al(III) center on the opposite face. Excitation of the porphyrin results in two sequential

Melanin is one the most common biological pigments. In humans, specialized cells called melanocytes synthesize the pigment from tyrosine and 3,4-dihydroxyphenylalanine via enzyme-catalyzed reactions and spontaneous processes. The formed melanin granule consists of nanoaggregates of oligomers containing different monomers. Although the main biological function of melanin is protection against damage

L-band electron paramagnetic resonance (EPR) in vivo dosimetry has the potential advantage of being able to accurately and sensitively measure the absorbed dose of ionizing radiation by measurements of teeth in situ. The equipment is transportable to the site where a radiation incident occurred and can be operated without specialized facilities. It, therefore, is very suitable for medical triage of

(1) Summarize revisions made to the implantable resonator (IR) design and results of testing to characterize biocompatibility; (2) Demonstrate safety of implantation and feasibility of deep tissue oxygenation measurement using electron paramagnetic resonance (EPR) oximetry. In vitro testing of the revised IR and in vivo implantation in rabbit brain and leg tissues. Revised IRs were fabricated with

A sensitive and rapid method for the detection of Vibrio alginolyticus is always in high demand. In this research, a magnetic relaxation switch sensor for the rapid detection of Vibrio alginolyticus has been successfully developed based on the aptamer-functionalized magnetic nanoparticle. The optimal concentration of aptamer for cross-linking was 6 μM, and the coupling time was 7 h. The optimal detection

For a model system of spins with two frequencies, a detailed analysis of the spin exchange in the EPR spectrum under saturation conditions in dilute solutions of paramagnetic particles is performed. For an arbitrary power of the microwave field, explicit analytical formulas are obtained for the frequency and width of the spectral lines, and for the contribution of the dispersion to the observed lines

EPR line shapes in fluid solution and electron spin relaxation times and lineshapes in frozen solution were measured at X-band for two dinitroxides. For dinitroxide 1, which has two proxyl nitroxides connected by an amide linkage, the fluid solution spectra are in the strong exchange limit (J >> nitrogen hyperfine coupling) and the interspin distance in glassy water:glycerol is about 8.8 Å. For dinitroxide

The necessity to develop a magnetometer for variations research in the mid-field magnetic strength with a relative error of 10–6 is justified. A new design of nuclear magnetometer which uses maser with flowing liquid is proposed. The block diagram of the magnetometer is presented, and the principle of its operation is described in detail. Furthermore, the conditions of occurrence of maser generation

Parahydrogen-induced polarization is a hyperpolarization method for enhancing nuclear magnetic resonance signals by chemical reactions/interactions involving the para spin isomer of hydrogen gas. This method has allowed for biomolecules to be hyperpolarized to such a level that they can be used for real time in vivo metabolic imaging. One particularly promising example is fumarate, which can be rapidly

This article presents an analysis of spurious signals’ influence on automatic frequency control (AFC) in EPR spectrometers. The primary source of spurious signals is leakage across the circulator in the microwave bridge. Additionally, the signals reflected from connectors in the line between the circulator and the resonator modify that signal. Spurious signals may degrade the performance of AFC, significantly