Effects of High Magnetic Fields on the Diffusion of Biologically Active Molecules

The diffusion of biologically active molecules is a ubiquitous process, controlling many mechanisms and the characteristic time scales for pivotal processes in living cells. Here, we show how a high static magnetic field (MF) affects the diffusion of paramagnetic and diamagnetic species including oxygen, hemoglobin, and drugs. We derive and solve the equation describing diffusion of such biologically active molecules in the presence of an MF as well as reveal the underlying mechanism of the MF’s effect on diffusion. We found that a high MF accelerates diffusion of diamagnetic species while slowing the diffusion of paramagnetic molecules in cell cytoplasm. When applied to oxygen and hemoglobin diffusion in red blood cells, our results suggest that an MF may significantly alter the gas exchange in an erythrocyte and cause swelling. Our prediction that the diffusion rate and characteristic time can be controlled by an MF opens new avenues for experimental studies foreseeing numerous biomedical applications.

Quantum-State Control and Manipulation of Paramagnetic Molecules with Magnetic Fields

Since external magnetic fields were first employed to deflect paramagnetic atoms in 1921, a range of magnetic field–based methods have been introduced to state-selectively manipulate paramagnetic species. These methods include magnetic guides, which selectively filter paramagnetic species from all other components of a beam, and magnetic traps, where paramagnetic species can be spatially confined for extended periods of time. However, many of these techniques were developed for atomic—rather than molecular—paramagnetic species. It has proven challenging to apply some of these experimental methods developed for atoms to paramagnetic molecules. Thanks to the emergence of new experimental approaches and new combinations of existing techniques, the past decade has seen significant progress toward the manipulation and control of paramagnetic molecules. This review identifies the key methods that have been implemented for the state-selective manipulation of paramagnetic molecules—discussing the motivation, state of the art, and future prospects of the field. Key applications include the ability to control chemical interactions, undertake precise spectroscopic measurements, and challenge our understanding of chemical reactivity at a fundamental level. Expected final online publication date for the Annual Review of Physical Chemistry, Volume 72 is April 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Effects of High Magnetic Fields on Diffusion of Biologically Active Molecules

The diffusion of biologically active molecules is a ubiquitous process, controlling many mechanisms and the characteristic time scales for pivotal processes in living cells. Here, we show how a high static magnetic field (MF) affects the diffusion of paramagnetic and diamagnetic species, including oxygen, hemoglobin, ROS and drugs. We derive and solve the equation describing diffusion of such biologically active molecules in the presence of a MF as well as reveal the underlying mechanism of the MF effect on diffusion. We find that a high MF accelerates diffusion of diamagnetic species while slowing the diffusion of paramagnetic molecules in cell cytoplasm. When applied to oxygen and hemoglobin diffusion in red blood cells, our results suggest that a MF may significantly alter the gas exchange in an erythrocyte and cause swelling. Our prediction that the diffusion rate and characteristic time can be controlled by a MF opens new avenues for experimental studies foreseeing numerous biomedical applications.

Limits on CP-violating hadronic interactions and proton EDM from paramagnetic molecules

Experiments with paramagnetic ground or metastable excited states of molecules (ThO, HfF+, YbF, YbOH, BaF, PbO, etc.) provide strong constraints on the electron electric dipole moment (EDM) and the coupling constant CSP of contact semileptonic interaction. We compute new contributions to CSP arising from the nucleon EDMs due to the combined electric and magnetic electron-nucleon interaction. This allows us to improve limits from the experiments with paramagnetic molecules on the CP-violating parameters, such as the proton EDM, |dp| < 1.1 × 10−23e·cm, the QCD vacuum angle, $$ \left|\overline{\theta}\right| $$ θ ¯ < 1.4 × 10−8, as well as the quark chromo-EDMs and the π-meson-nucleon couplings. Our results may also be used to search for the axion dark matter which produces oscillating $$ \overline{\theta} $$ θ ¯ .

Electrochemical deposition of a semiconducting gold dithiolene complex with NIR absorption

Gold dithiolene complex can be electrodeposited as a film of neutral, paramagnetic molecules with strong NIR absorption.

Gas Sensing of Monolayer GeSe: A First-Principles Study

The adsorption of various gas molecules (H2, H2O, CO, NH3, NO and NO[Formula: see text] on monolayer GeSe were investigated by first-principles calculations. The most stable configurations, the adsorption energies, and the amounts of charge transfer were determined. Owing to the appropriate adsorption energies and the non-negligible charge transfers, monolayer GeSe could be a promising candidate as a sensor for NH3, CO, NO and NO2. According to the band structures of the H2O, CO, NH3, NO and NO2 adsorbed systems, the reductions of the bandgaps are caused by the orbital hybridizations between the gas molecules and the underlying GeSe. The partial densities of states reveal the degrees of these orbital hybridizations. The mechanisms of charge transfer are discussed in the light of both traditional and orbital mixing charge transfer theories. The charge transfer of the paramagnetic molecules NO and NO2 could be governed by both charge transfer mechanisms, while for the other gas molecules H2, H2O, CO and NH3, it was most likely determined by the mixing of the HOMO or LUMO with the GeSe orbitals.

Characterizing maser polarization: effects of saturation, anisotropic pumping, and hyperfine structure

Context. The polarization of masers contains information on the magnetic field strength and direction of the regions they occur in. Many maser polarization observations have been performed over the last 30 years. However, versatile maser polarization models that can aide in the interpretation of these observations are not available. Aims. We developed a program suite that can compute the polarization by a magnetic field of any non-paramagnetic maser species at arbitrarily high maser saturation. Furthermore, we investigated the polarization of masers by non-Zeeman polarizing effects. We present a general interpretive structure for maser polarization observations. Methods. We expanded existing maser polarization theories of non-paramagnetic molecules and incorporated them in a numerical modeling program suite. Results. We present a modeling program called CHAracterizes Maser Polarization (CHAMP) that can examine the polarization of masers of arbitrarily high maser saturation and high angular momentum. Hyperfine multiplicity of the maser-transition can also be incorporated. The user is able to investigate non-Zeeman polarizing mechanisms such as anisotropic pumping and polarized incident seed radiation. We present an analysis of the polarization of v = 1 SiO masers and the 22 GHz water maser. We comment on the underlying polarization mechanisms, and also investigate non-Zeeman effects. Conclusions. We identify the regimes where different polarizing mechanisms will be dominant and present the polarization characteristics of the SiO and water masers. From the results of our calculations, we identify markers to recognize alternative polarization mechanisms. We show that comparing randomly generated linear versus circular polarization (pL − pV) scatter-plots at fixed magnetic field strength to the observationally obtained pL − pV scatter can be a promising method of ascertaining the average magnetic field strength of a large number of masers.