Magnetic resonance techniques are successfully utilized in a broad range of scientific disciplines and in various practical applications, with medical magnetic resonance imaging being the most widely known example. Currently, both fundamental and applied magnetic resonance are enjoying a major boost owing to the rapidly developing field of spin hyperpolarization. Hyperpolarization techniques are able to enhance signal intensities in magnetic resonance by several orders of magnitude, and thus to largely overcome its major disadvantage of relatively low sensitivity. This provides new impetus for existing applications of magnetic resonance and opens the gates to exciting new possibilities. In this review, we provide a unified picture of the many methods and techniques that fall under the umbrella term “hyperpolarization” but are currently seldom perceived as integral parts of the same field. Specifically, before delving into the individual techniques, we provide a detailed analysis of the underlying principles of spin hyperpolarization. We attempt to uncover and classify the origins of hyperpolarization, to establish its sources and the specific mechanisms that enable the flow of polarization from a source to the target spins. We then give a more detailed analysis of individual hyperpolarization techniques: the mechanisms by which they work, fundamental and technical requirements, characteristic applications, unresolved issues, and possible future directions. We are seeing a continuous growth of activity in the field of spin hyperpolarization, and we expect the field to flourish as new and improved hyperpolarization techniques are implemented. Some key areas for development are in prolonging polarization lifetimes, making hyperpolarization techniques more generally applicable to chemical/biological systems, reducing the technical and equipment requirements, and creating more efficient excitation and detection schemes. We hope this review will facilitate the sharing of knowledge between subfields within the broad topic of hyperpolarization, to help overcome existing challenges in magnetic resonance and enable novel applications.

Spin Hyperpolarization in Modern Magnetic Resonance

Preface. 1 Introduction and survey. 1.1 Information, computers and quantum mechanics. 1.1.1 Digital information. 1.1.2 Moore's law. 1.1.3 Emergence of quantum behavior. 1.1.4 Energy dissipation in computers. 1.2 Quantum computer basics. 1.2.1 Quantum information. 1.2.2 Quantum communication. 1.2.3 Basics of quantum information processing. 1.2.4 Decoherence. 1.2.5 Implementation. 1.3 History of quantum information processing. 1.3.1 Initial ideas. 1.3.2 Quantum algorithms. 1.3.3 Implementations. 2 Physics of computation. 2.1 Physical laws and information processing. 2.1.1 Hardware representation. 2.1.2 Quantum vs. classical information processing. 2.2 Limitations on computer performance. 2.2.1 Switching energy. 2.2.2 Entropy generation and Maxwell's demon. 2.2.3 Reversible logic. 2.2.4 Reversible gates for universal computers. 2.2.5 Processing speed. 2.2.6 Storage density. 2.3 The ultimate laptop. 2.3.1 Processing speed. 2.3.2 Maximum storage density. 3 Elements of classical computer science. 3.1 Bits of history. 3.2 Boolean algebra and logic gates. 3.2.1 Bits and gates. 3.2.2 2 bit logic gates. 3.2.3 Minimum set of irreversible gates. 3.2.4 Minimum set of reversible gates. 3.2.5 The CNOT gate. 3.2.6 The Toffoli gate. 3.2.7 The Fredkin gate. 3.3 Universal computers. 3.3.1 The Turing machine. 3.3.2 The Church Turing hypothesis. 3.4 Complexity and algorithms. 3.4.1 Complexity classes. 3.4.2 Hard and impossible problems. 4 Quantum mechanics. 4.1 General structure. 4.1.1 Spectral lines and stationary states. 4.1.2 Vectors in Hilbert space. 4.1.3 Operators in Hilbert space. 4.1.4 Dynamics and the Hamiltonian operator. 4.1.5 Measurements. 4.2 Quantum states. 4.2.1 The two dimensional Hilbert space: qubits, spins, and photons. 4.2.2 Hamiltonian and evolution. 4.2.3 Two or more qubits. 4.2.4 Density operator. 4.2.5 Entanglement and mixing. 4.2.6 Quantification of entanglement. 4.2.7 Bloch sphere. 4.2.8 EPR correlations. 4.2.9 Bell's theorem. 4.2.10 Violation of Bell's inequality. 4.2.11 The no cloning theorem. 4.3 Measurement revisited. 4.3.1 Quantum mechanical projection postulate. 4.3.2 The Copenhagen interpretation. 4.3.3 Von Neumann's model. 5 Quantum bits and quantum gates. 5.1 Single qubit gates. 5.1.1 Introduction. 5.1.2 Rotations around coordinate axes. 5.1.3 General rotations. 5.1.4 Composite rotations. 5.2 Two qubit gates. 5.2.1 Controlled gates. 5.2.2 Composite gates. 5.3 Universal sets of gates. 5.3.1 Choice of set. 5.3.2 Unitary operations. 5.3.3 Two qubit operations. 5.3.4 Approximating single qubit gates. 6 Feynman's contribution. 6.1 Simulating physics with computers. 6.1.1 Discrete system representations. 6.1.2 Probabilistic simulations. 6.2 Quantum mechanical computers. 6.2.1 Simple gates. 6.2.2 Adder circuits. 6.2.3 Qubit raising and lowering operators. 6.2.4 Adder Hamiltonian. 7 Errors and decoherence. 7.1 Motivation. 7.1.1 Sources of error. 7.1.2 A counterstrategy. 7.2 Decoherence. 7.2.1 Phenomenology. 7.2.2 Semiclassical description. 7.2.3 Quantum mechanical model. 7.2.4 Entanglement and mixing. 7.3 Error correction. 7.3.1 Basics. 7.3.2 Classical error correction. 7.3.3 Quantum error correction. 7.3.4 Single spin flip error. 7.3.5 Continuous phase errors. 7.3.6 General single qubit errors. 7.3.7 The quantum Zeno effect. 7.3.8 Stabilizer codes. 7.3.9 Fault tolerant computing. 7.4 Avoiding errors. 7.4.1 Basics. 7.4.2 Decoherence free subspaces. 7.4.3 NMR in Liquids. 7.4.4 Scaling considerations. 8 Tasks for quantum computers. 8.1 Quantum versus classical algorithms. 8.1.1 Why Quantum? 8.1.2 Classes of quantum algorithms. 8.2 The Deutsch algorithm: Looking at both sides of a coin at the same time. 8.2.1 Functions and their properties. 8.2.2 Example: one qubit functions. 8.2.3 Evaluation. 8.2.4 Many qubits. 8.2.5 Extensions and generalizations. 8.3 The Shor algorithm: It's prime time. 8.3.1 Some number theory. 8.3.2 Factoring strategy. 8.3.3 The core of Shor's algorithm. 8.3.4 The quantum Fourier transform. 8.3.5 Gates for the QFT. 8.4 The Grover algorithm: Looking for a needle in a haystack. 8.4.1 Oracle functions. 8.4.2 The search algorithm. 8.4.3 Geometrical analysis. 8.4.4 Quantum counting. 8.4.5 Phase estimation. 8.5 Quantum simulations. 8.5.1 Potential and limitations. 8.5.2 Motivation. 8.5.3 Simulated evolution. 8.5.4 Implementations. 9 How to build a quantum computer. 9.1 Components. 9.1.1 The network model. 9.1.2 Some existing and proposed implementations. 9.2 Requirements for quantum information processing hardware. 9.2.1 Qubits. 9.2.2 Initialization. 9.2.3 Decoherence time. 9.2.4 Quantum gates. 9.2.5 Readout. 9.3 Converting quantum to classical information. 9.3.1 Principle and strategies. 9.3.2 Example: Deutsch Jozsa algorithm. 9.3.3 Effect of correlations. 9.3.4 Repeated measurements. 9.4 Alternatives to the network model. 9.4.1 Linear optics and measurements. 9.4.2 Quantum cellular automata. 9.4.3 One way quantum computer. 10 Liquid state NMR quantum computer. 10.1 Basics of NMR. 10.1.1 System and interactions. 10.1.2 Radio frequency field. 10.1.3 Rotating frame. 10.1.4 Equation of motion. 10.1.5 Evolution. 10.1.6 NMR signals. 10.1.7 Refocusing. 10.2 NMR as a molecular quantum computer. 10.2.1 Spins as qubits. 10.2.2 Coupled spin systems. 10.2.3 Pseudo / effective pure states. 10.2.4 Single qubit gates. 10.2.5 Two qubit gates. 10.2.6 Readout. 10.2.7 Readout in multi spin systems. 10.2.8 Quantum state tomography. 10.2.9 DiVincenzo's criteria. 10.3 NMR Implementation of Shor's algorithm. 10.3.1 Qubit implementation. 10.3.2 Initialization. 10.3.3 Computation. 10.3.4 Readout. 10.3.5 Decoherence. 11 Ion trap quantum computers. 11.1 Trapping ions. 11.1.1 Ions, traps and light. 11.1.2 Linear traps. 11.2 Interaction with light. 11.2.1 Optical transitions. 11.2.2 Motional effects. 11.2.3 Basics of laser cooling. 11.3 Quantum information processing with trapped ions. 11.3.1 Qubits. 11.3.2 Single qubit gates. 11.3.3 Two qubit gates. 11.3.4 Readout. 11.4 Experimental implementations. 11.4.1 Systems. 11.4.2 Some results. 11.4.3 Problems. 12 Solid state quantum computers. 12.1 Solid state NMR/EPR. 12.1.1 Scaling behavior of NMR quantum information processors. 12.1.2 31P in silicon. 12.1.3 Other proposals. 12.1.4 Single spin readout. 12.2 Superconducting systems. 12.2.1 Charge qubits. 12.2.2 Flux qubits. 12.2.3 Gate operations. 12.2.4 Readout. 12.3 Semiconductor qubits. 12.3.1 Materials. 12.3.2 Excitons in quantum dots. 12.3.3 Electron spin qubits. 13 Quantum communication. 13.1 Quantum only tasks. 13.1.1 Quantum teleportation. 13.1.2 (Super ) Dense coding. 13.1.3 Quantum key distribution. 13.2 Information theory. 13.2.1 A few bits of classical information theory. 13.2.2 A few bits of quantum information theory. Appendix. A. Two spins 1/2: Singlet and triplet states. B. Symbols and abbreviations. Bibliography. Index.

Quantum Computing: A Short Course from Theory to Experiment

Environmental pollution is escalating due to rapid global development that often prioritizes human needs over planetary health. Despite global efforts to mitigate legacy pollutants, the continuous introduction of new substances remains a major threat to both people and the planet. In response, global initiatives are focusing on risk assessment and regulation of emerging contaminants, as demonstrated by the ongoing efforts to establish the UN's Intergovernmental Science-Policy Panel on Chemicals, Waste, and Pollution Prevention. This review identifies the sources and impacts of emerging contaminants on planetary health, emphasizing the importance of adopting a One Health approach. Strategies for monitoring and addressing these pollutants are discussed, underscoring the need for robust and socially equitable environmental policies at both regional and international levels. Urgent actions are needed to transition toward sustainable pollution management practices to safeguard our planet for future generations. 

Emerging Contaminants: A One Health Perspective

Bee bread is product with long history used mainly in folk medicine. Nowadays, bee bread is growing in commercial interest due to its high nutritional properties. The objective of this study was to determine biological activity of ethanolic extract of bee bread obtained from selected region of Ukraine - Poltava oblast, Kirovohrad oblast, Vinnica oblast, Kyiv oblast, Dnepropetrovsk oblast. The antioxidant activity was measured with the radical scavenging assays using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical as well as phosphomolybdenum assay. Total polyphenol content was determined with Folin-Ciocalteau reagent and total flavonoid content by aluminium-chloride method. Secondary was also evaluated antimicrobial activity in bee bread samples with disc diffusion method and minimum inhibitory concentrations. Antioxidant activity expressed as mg TEAC per g of dry weight (Trolox equivalent antioxidant capacity) was the highest in bee bread from Poltava oblast in DPPH and also phosphomolybdenum method. Samples of bee bread contained high levels of total polyphenols (12.36 - 18.24 mg GAE - gallic acid equivalent per g of dry weight) and flavonoids (13.56 - 18.24 μg QE - quercetin equivalent per g of dry weight) with the best values of bee bread from Poltava oblast. An elevated level of antioxidant potential in the bee bread determines its biological properties, which conditioned of the biological active substances. The best antibacterial activity of bee bred with disc diffusion method was found against Bacillus thuringiensis CCM 19. The antibacterial activity inhibited by the bee bread extract in the present study indicate that best minimal inhibition concentration was against bacteria Escherichia coli CCM 3988 and Salmonella enterica subs. enterica CCM 3807.

https://www.potravinarstvo.com/journal1/index.php/potravinarstvo/article/download/558/pdf

Bee bread - perspective source of bioactive compounds for future

The water-endofullerene H2O@C60 provides a unique chemical system in which freely rotating water molecules are confined inside homogeneous and symmetrical carbon cages. The spin conversion between the ortho and para species of the endohedral H2O was studied in the solid phase by low-temperature nuclear magnetic resonance. The experimental data are consistent with a second-order kinetics, indicating a bimolecular spin conversion process. Numerical simulations suggest the simultaneous presence of a spin diffusion process allowing neighbouring ortho and para molecules to exchange their angular momenta. Cross-polarization experiments found no evidence that the spin conversion of the endohedral H2O molecules is catalysed by 13C nuclei present in the cages.

/pdf/nuclear-spin-conversion-of-water-inside-fullerene-cages-2a8quy0g27.pdf

Nuclear spin conversion of water inside fullerene cages detected by low-temperature nuclear magnetic resonance.

Unexpected multiplet patterns induced by the Haupt-effect

The Haupt-effect is a rather seldom used hyperpolarization method. It is based on the interdependence between nuclear spin states and rotational states of nearly free rotating methyl groups having C3 symmetry. A sudden change in temperature from 4.2 K to room temperature by fast dissolution yields considerably enhanced 13C and 1H resonance signals. This phenomenon is now termed quantum rotor induced polarization. More than 40 substances have been studied by this approach in order to identify them as polarizable by the ‘Haupt-effect in the liquid state’. Influencing factors have been analyzed systematically. It could be concluded that substances having a high tunneling frequency, which is due to a small and narrow potential barrier, are most likely to feature quantum rotor induced polarization-enhanced signals. Copyright © 2013 John Wiley & Sons, Ltd.

Experimental boundaries of the quantum rotor induced polarization (QRIP) in liquid state NMR

Transfer of the Haupt-hyperpolarization to neighbor spins.

The detection and characterization of trapped water molecules in chemical entities and biomacromolecules remains a challenging task for solid materials. We herein present proton-detected solid-state Nuclear Magnetic Resonance (NMR) experiments at 100 kHz magic-angle spinning and at high static magnetic-field strengths (28.8 T) enabling the detection of a single water molecule fixed in the calix[4]arene cavity of a lanthanide complex by a combination of three types of non-covalent interactions. The water proton resonances are detected at a chemical-shift value close to zero ppm, which we further confirm by quantum-chemical calculations. Density Functional Theory calculations pinpoint to the sensitivity of the proton chemical-shift value for hydrogen-π interactions. Our study highlights how proton-detected solid-state NMR is turning into the method-of-choice in probing weak non-covalent interactions driving a whole branch of molecular-recognition events in chemistry and biology.

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/anie.202217725

Probing a Hydrogen-π Interaction Involving a Trapped Water Molecule in the Solid State.

High resolution mass spectrometry (HRMS) coupled to either gas chromatography or reversed-phase liquid chromatography is the generic method to identify unknown disinfection byproducts (DBPs) but can easily overlook their highly polar fractions. In this study, we applied an alternative chromatographic separation method, supercritical fluid chromatography-HRMS, to characterize DBPs in disinfected water. In total, 15 DBPs were tentatively identified for the first time as haloacetonitrilesulfonic acids, haloacetamidesulfonic acids, and haloacetaldehydesulfonic acids. Cysteine, glutathione, and p-phenolsulfonic acid were found as precursors during lab-scale chlorination, with cysteine providing the highest yield. A mixture of the labeled analogues of these DBPs was prepared by chlorination of 13C3-15N-cysteine and analyzed using nuclear magnetic resonance spectroscopy for structural confirmation and quantification. A total of 6 drinking water treatment plants utilizing various source waters and treatment trains produced sulfonated DBPs upon disinfection. Those were widespread in the tap water of 8 cities across Europe, with estimated concentrations up to 50 and 800 ng/L for total haloacetonitrilesulfonic acids and haloacetaldehydesulfonic acids, respectively. Up to 850 ng/L haloacetonitrilesulfonic acids were found in 3 public swimming pools. Considering the stronger toxicity of haloacetonitriles, haloacetamides, and haloacetaldehydes than the regulated DBPs, these newly found sulfonic acid derivatives may also pose a health risk.

https://pubs.acs.org/doi/pdf/10.1021/acs.est.2c05536

Revisiting Disinfection Byproducts with Supercritical Fluid Chromatography-High Resolution-Mass Spectrometry: Identification of Novel Halogenated Sulfonic Acids in Disinfected Drinking Water

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