The Relationships Between Cortical Activity while Observing Images Featuring Different Degrees of Ambiguity and Ambiguity Tolerance.

We performed a fMRI study during which 18 healthy subjects passively viewed abstract images and tried to name them. The images were geometric primitives, impossible images (Penrose images), and ambiguous images (Rorschach inkblots). Activation and deactivation areas were revealed for each task.

Metabolic response of the Siberian wood frog Rana amurensis to extreme hypoxia.

The Siberian wood frog Rana amurensis is a recently discovered example of extreme hypoxia tolerance that is able to survive several months without oxygen. We studied metabolomic profiles of heart and liver of R. amurensis exposed to 17 days of extreme hypoxia.

Heterogeneous Parahydrogen-Induced Polarization of Diethyl Ether for Magnetic Resonance Imaging Applications.

Magnetic resonance imaging (MRI) with the use of hyperpolarized gases as contrast agents provides valuable information on lungs structure and function. While the technology of Xe hyperpolarization for clinical MRI research is well developed, it requires the expensive equipment for production and detection of hyperpolarized Xe. Herein we present the H hyperpolarization of diethyl ether vapor that can be imaged on any clinical MRI scanner.

Total Correlation Spectroscopy across All NMR-Active Nuclei by Mixing at Zero Field.

Multidimensional nuclear magnetic resonance (NMR) is based on a combination of well-established building blocks for polarization transfer. These blocks are used to design correlation experiments through one or a few chemical bonds or through space. Here, we introduce a building block that enables polarization transfer across all NMR-active nuclei in a coupled network of spins: isotropic mixing at zero and ultralow field (ZULF).

Giant magnetic field effects in donor-acceptor triads: On the charge separation and recombination dynamics in triarylamine-naphthalenediimide triads with bis-diyprrinato-palladium(II), porphodimethenato-palladium(II), and palladium(II)-porphyrin photosensitizers.

A series of triads consisting of a triarylamine donor, a naphthalenediimide acceptor, and a palladium photosensitizer bridge was investigated for the photoinduced electron transfer processes and the spin chemistry involved. In this series, the ligand in the palladium photosensitizer was varied from bis-dipyrrinato to porphodimethenato and to a porphyrin. With the porphyrin photosensitizer, no charge separated state could be reached.

Ferromagnetically Coupled S=1 Chains in Crystals of Verdazyl-Nitronyl Nitroxide Diradicals.

Thermally stable organic diradicals with a triplet ground state along with large singlet-triplet energy gap have significant potential for advanced technological applications. A series of phenylene-bridged diradicals with oxoverdazyl and nitronyl nitroxide units were synthesized via a palladium-catalyzed cross-coupling reaction of iodoverdazyls with a nitronyl nitroxide-2-ide gold(I) complex with high yields. The diradicals exhibit high stability and do not decompose in an inert atmosphere up to 180 °C.

A Synergy and Struggle of EPR, Magnetometry and NMR: A Case Study of Magnetic Interaction Parameters in a Six-Coordinate Cobalt(II) Complex.

Herein, we combine for the first time SQUID magnetometry, cw-EPR, THz-EPR, and paramagnetic NMR spectroscopies to study the magnetic properties of a high-spin cobalt(II) heteroscorpionate complex. Complementary information provided by these methods allowed precise determination of the magnetic interaction parameters, thereby removing the ambiguity inherit to single-method studies. We systematically investigate the extent to which information about the magnetic interaction parameters can be deduced from reduced data sets.

Parahydrogen-Induced Polarization of Diethyl Ether Anesthetic.

The growing interest in magnetic resonance imaging (MRI) for assessing regional lung function relies on the use of nuclear spin hyperpolarized gas as a contrast agent. The long gas-phase lifetimes of hyperpolarized Xe make this inhalable contrast agent acceptable for clinical research today despite limitations such as high cost, low throughput of production and challenges of Xe imaging on clinical MRI scanners, which are normally equipped with proton detection only. We report on low-cost and high-throughput preparation of proton-hyperpolarized diethyl ether, which can be potentially employed for pulmonary imaging with a nontoxic, simple, and sensitive overall strategy using proton detection commonly available on all clinical MRI scanners.

The {Re} Tetrahedral Cyanometalate Cluster Anion [{Re(μ-CCN)}(CN)] with Inner (μ-CCN) Ligands and Its Features in Coordination of Cu Cations.

A reaction between ReI and KCN at elevated temperature led to the formation of the new cyanometalate cluster anion [{Re(μ-CCN)}(CN)] (). The anion contains μ-CCN ligands, which are stabilized by the coordination to the triangular faces of the tetrahedral {Re} metallocluster in a μ mode. The compound crystallized as a potassium salt, and its crystal structure was determined by single-crystal X-ray diffraction analysis.

Structural Transitions of the Metal-Organic Framework DUT-49(Cu) upon Physi- and Chemisorption Studied by Electron Paramagnetic Resonance Spectroscopy.

Flexible metal-organic frameworks (MOFs) exhibit a variety of phenomena attractive for basic and applied science. DUT-49(Cu) is one of the remarkable representatives of such MOFs, where phase transitions are coupled to pressure amplification and "negative gas adsorption". In this work we report important insights into structural transitions of DUT-49(Cu) upon physi- and chemisorption of gases and volatile liquids obtained by electron paramagnetic resonance (EPR) spectroscopy.

Electron Spin Relaxation of Photoexcited Porphyrin in Water-Glycerol Glass.

Recently, the photoexcited triplet state of porphyrin was proposed as a promising spin-label for pulsed dipolar electron paramagnetic resonance (EPR). Herein, we report the factors that determine the electron spin echo dephasing of the photoexcited porphyrin in a water-glycerol matrix. The electron spin relaxation of a water-soluble porphyrin was measured by Q-band EPR, and the temperature dependence and the effect of solvent deuteration on the relaxation times were studied.

Modulating the Magnetic Properties of Copper(II)/Nitroxyl Heterospin Complexes by Suppression of the Jahn-Teller Distortion.

A series of six-coordinate [Cu(L)L][BF] (L = 2,6-bis{1-oxyl-4,4,5,5-tetramethyl-4,5-dihydro-1-imidazol-2-yl}pyridine) complexes are reported. Ferromagnetic coupling between the Cu and L ligand spins is enhanced by an L coligand with distal methyl substituents, which is attributed to a sterically induced suppression of its Jahn-Teller distortion.

Pilot multi-site quality assurance study of batch-mode clinical-scale automated xenon-129 hyperpolarizers.

We present a pilot quality assurance (QA) study of spin-exchange optical pumping (SEOP) performed on two nearly identical second-generation (GEN-2) automated batch-mode clinical-scale Xe hyperpolarizers, each utilizing a convective forced air oven, high-power (~170 W) continuous pump laser irradiation, and xenon-rich gas mixtures (~1.30 atm partial pressure). In one study, the repeatability of SEOP in a 1000 Torr Xe/900 Torr N/100 Torr He (2000 Torr total pressure) gas mixture is evaluated over the course of ~700 gas loading cycles, with negligible decrease in performance during the first ~200 cycles, and with high Xe polarization levels (avg.

Chemical Reaction Monitoring using Zero-Field Nuclear Magnetic Resonance Enables Study of Heterogeneous Samples in Metal Containers.

We demonstrate that heterogeneous/biphasic chemical reactions can be monitored with high spectroscopic resolution using zero-field nuclear magnetic resonance spectroscopy. This is possible because magnetic susceptibility broadening is negligible at ultralow magnetic fields. We show the two-step hydrogenation of dimethyl acetylenedicarboxylate with para-enriched hydrogen gas in conventional glass NMR tubes, as well as in a titanium tube.

Mating with immunised male mice affects the phenotype of adult progeny.

The life-history theory suggests that parental experience of the environment is passed to offspring, which allows them to adapt to prevailing conditions. This idea is supported from the mother's side, but to a much less extent from the father's side. Here, we investigated the effect of immunising fathers on pre- and neonatal development and on immune and neuroendocrine phenotypes of their offspring in C57BL/6J mice.

Helium-rich mixtures for improved batch-mode clinical-scale spin-exchange optical pumping of Xenon-129.

We present studies of spin-exchange optical pumping (SEOP) using ternary xenon-nitrogen-helium gas mixtures at high xenon partial pressures (up to 1330 Torr partial pressure at loading, out of 2660 Torr total pressure) in a 500-mL volume SEOP cell, using two automated batch-mode clinical-scale Xe hyperpolarizers operating under continuous high-power (~170 W) pump laser irradiation. In this pilot study, we explore SEOP in gas mixtures with up to 45% He content under a wide range of experimental conditions. When an aluminum jacket cooling/heating design was employed (GEN-3 hyperpolarizer), Xe polarization (%P) of 55.

Algorithmic cooling of nuclear spins using long-lived singlet order.

Algorithmic cooling methods manipulate an open quantum system in order to lower its temperature below that of the environment. We achieve significant cooling of an ensemble of nuclear spin-pair systems by exploiting the long-lived nuclear singlet state, which is an antisymmetric quantum superposition of the "up" and "down" Zeeman states. The effect is demonstrated by nuclear magnetic resonance experiments on a molecular system containing a coupled pair of near-equivalent C nuclei.

Easy Ligand Activation in the Coordination Sphere of Ru inside the [PWO] Backbone.

Irradiation of the Keggin-type [PWO{Ru(NO)}] () polyoxometalate in CHCN results in rapid NO ligand elimination with the formation of [PWO{Ru(CHCN)}] (). This complex offers an easy entry into the Ru-based chemistry of the {PWRu} complex. Attempts to substitute N for CHCN in the presence of an NaN excess lead a variety of products: (i) [PWO{Ru(N)}] (); (ii) [PWO{Ru(NHC-CH)}] () as a click-reaction product; and (iii) [PWO{Ru(N)}] ().

A Titanium Metal-Organic Framework with Visible-Light-Responsive Photocatalytic Activity.

The one-step synthesis and characterization of a new and robust titanium-based metal-organic framework, ACM-1, is reported. In this structure, which is based on infinite Ti-O chains and 4,4',4'',4'''-(pyrene-1,3,6,8-tetrayl) tetrabenzoic acid as a photosensitizer ligand, the combination of highly mobile photogenerated electrons and a strong hole localization at the organic linker results in large charge-separation lifetimes. The suitable energies for band gap and conduction band minimum (CBM) offer great potential for a wide range of photocatalytic reactions, from hydrogen evolution to the selective oxidation of organic substrates.

Exchange interactions in photoinduced magnetostructural states of copper(ii)-nitroxide spin dyads.

Copper(ii) complexes with stable nitroxide radicals are capable of magnetostructural spin-crossover like anomalies induced by external stimuli. Photoswitching in such systems is particularly important; however, retrieving the properties of photoinduced states is challenging and requires development of novel approaches. In this work, we investigate the exchange interactions in metastable photoinduced states of two compounds containing copper(ii)-nitroxide dyads.

Human Serum Albumin Labelled with Sterically-Hindered Nitroxides as Potential MRI Contrast Agents.

Four albumin-nitroxide conjugates were prepared and tested as metal-free organic radical contrast agents (ORCAs) for magnetic resonance imaging (MRI). Each human serum albumin (HSA) carrier bears multiple nitroxides conjugated via homocysteine thiolactones. These molecular conjugates retain important physical and biological properties of their HSA component, and the resistance of their nitroxide groups to bioreduction was retained or enhanced.