Setup for pressurizing thin films through the superconductor-insulator transition.

We describe an experimental setup designed for transport measurement of thin disordered superconducting films as a function of pressure up to several GPa. We use a specially designed single screw diamond anvil cell that allows the gradual increase of high pressure at cryogenic temperatures. By depositing amorphous films of disordered superconducting indium oxide directly on the diamond, we avoid the effect of pressure-induced structural changes in the substrate.

Hydrogen evolution catalysis by terminal molybdenum-oxo complexes.

Stable complexes with terminal triply bound metal-oxygen bonds are usually not considered as valuable catalysts for the hydrogen evolution reaction (HER). We now report the preparation of three conceptually different (oxo)molybdenum(V) corroles for testing if proton-assisted 2-electron reduction will lead to hyper-reactive molybdenum(III) capable of converting protons to hydrogen gas. The upto 670 mV differences in the [(oxo)Mo(IV)]/[(oxo)Mo(III)] redox potentials of the dissolved complexes came into effect by the catalytic onset potential for proton reduction thereby, significantly earlier than their reduction process in the absence of acids, but the two more promising complexes were not stable at practical conditions.

Engineering Individual Oxygen Vacancies: Domain-Wall Conductivity and Controllable Topological Solitons.

Nanoscale devices that utilize oxygen vacancies in two-dimensional metal-oxide structures garner much attention due to conductive, magnetic, and even superconductive functionalities they exhibit. Ferroelectric domain walls have been a prominent recent example because they serve as a hub for topological defects and hence are attractive for next-generation data technologies. However, owing to the light weight of oxygen atoms and localized effects of their vacancies, the atomic-scale electrical and mechanical influence of individual oxygen vacancies has remained elusive.

The Initial Oxidation of HfNiSn Half-Heusler Alloy by Oxygen and Water Vapor.

The MNiSn (M = Ti, Zr, Hf) -type semiconductor half-Heusler alloys are leading candidates for the use as highly efficient waste heat recovery devices at elevated temperatures. For practical applications, it is crucial to consider also the environmental stability of the alloys at working conditions, and therefore it is required to characterize and understand their oxidation behavior. This work is focused on studying the surface composition and the initial oxidation of HfNiSn alloy by oxygen and water vapor at room temperature and at 1000 K by utilizing X-ray photoelectron spectroscopy.

Advanced sol-gel process for efficient heterogeneous ring-closing metathesis.

Olefin metathesis, a powerful synthetic method with numerous practical applications, can be improved by developing heterogeneous catalysts that can be recycled. In this study, a single-stage process for the entrapment of ruthenium-based catalysts was developed by the sol-gel process. System effectiveness was quantified by measuring the conversion of the ring-closing metathesis reaction of the substrate diethyl diallylmalonate and the leakage of the catalysts from the matrix.

Ultrafast high-capacity capture and release of uranium by a light-switchable nanotextured surface.

Nuclear power is growing in demand as a promising sustainable energy source, its most prevalent source being uranium salts. The resulting processing and transportation of uranium raise concerns regarding the environmental impact and risks for human health. Close proximity to uranium mines puts populations at higher risk for exposure due to elevated uranium concentrations.

Oligomers Intermediates in Between Two New Distinct Homonuclear Uranium(IV) DOTP Complexes*.

Two new aqueous U complexes were synthesized by the interaction between the tetravalent uranium cation and the (1,4,7,10-Tetraazacyclododecane-1,4,7,10-tetra(methylene phosphonic acid) (DOTP) macrocyclic ligand. Two distinct homonuclear complexes were identified; the first was characterized by X-ray crystallography as a unique "out-of-cage", [U(DOTPH ) ] complex, in which the U cation is octa-coordinated to 4 phosphonic arms from each ligand in a square anti-prism geometry, with a C symmetry. The second is the "in-cage" [U(DOTPH )] complex, in which the tetravalent cation is located between the macrocycle O and N planes.

Synergistic Doping and Surface Decoration of Carbon Nitride Macrostructures by Single Crystal Design.

Tailored design of hybrid carbon nitride (CN) materials is quite challenging because of the drawbacks of the solid-state reaction, and the utilization of single crystals containing C-N monomers as reactants for the high-temperature reaction has been proven to imprint a given chemical composition, morphology, or electronic structure. We report the one-pot synthesis of alkali-containing CN macrostructures with ionic crystals on its surface by utilizing a tailored melamine-hydrochloride-based molecular single crystal containing NaCl and KCl as reactants. Structural and optical investigations reveal that upon calcination, molecular doping with Na and K is achieved, and additionally, the ionic species remain on the surface of the materials, resulting in an enhanced H evolution performance through water splitting owing to a high ionic strength of the reaction media.

Redox Properties of CeDOTA in Carbonated Aqueous Solutions. A Radiolytic and an Electrochemical Study.

The redox chemistry of CeDOTA in carbonate solutions was studied using electrochemistry and radiolysis techniques (continuous radiolysis and pulse radiolysis). Spectroscopic measurements point out that the species present in the solutions at high bicarbonate concentrations are [CeDOTA(CO)] (or less plausible [CeDOTA(HCO)]) with the carbonate (bicarbonate) anion as the ninth ligand versus [CeDOTA(HO)] present in the absence of bicarbonate. Electrochemical results show a relatively low increase in the thermodynamic stabilization of the redox couple Ce in the presence of carbonate versus its aqueous analogue.

The effect of green Mediterranean diet on cardiometabolic risk; a randomised controlled trial.

Background: A Mediterranean diet is favourable for cardiometabolic risk.

Objective: To examine the residual effect of a green Mediterranean diet, further enriched with green plant-based foods and lower meat intake, on cardiometabolic risk.

Methods: For the DIRECT-PLUS parallel, randomised clinical trial we assigned individuals with abdominal obesity/dyslipidaemia 1:1:1 into three diet groups: healthy dietary guidance (HDG), Mediterranean and green Mediterranean diet, all combined with physical activity.

Radicals in 'biologically relevant' concentrations behave differently: Uncovering new radical reactions following the reaction of hydroxyl radicals with DMSO.

Methyl radicals play key roles in various chemical and biological processes. Mechanistic studies of methyl radicals with their precursor, Dimethyl Sulfoxide (DMSO), were extensively studied. Though the involved mechanisms seemed to be clarified, essentially none of the studies have been performed at conditions relevant to both biological and catalytic systems, i.

DFT and Empirical Considerations on Electrocatalytic Water/Carbon Dioxide Reduction by CoTMPyP in Neutral Aqueous Solutions*.

A combined experimental and density functional theory (DFT) investigation was employed in order to examine the mechanism of electrochemical CO reduction and H formation from water reduction in neutral aqueous solutions. A water soluble cobalt porphyrin, cobalt [5,10,15,20-(tetra-N-methyl-4-pyridyl)porphyrin], (CoTMPyP), was used as catalyst. The possible attachment of different axial ligands as well as their effect on the electrocatalytic cycles were examined.

The Role of Carbonate in Catalytic Oxidations.

CO, HCO, and CO are present in all aqueous media at pH > 4 if no major effort is made to remove them. Usually the presence of CO/HCO/CO is either forgotten or considered only as a buffer or proton transfer catalyst. Results obtained in the last decades point out that carbonates are key participants in a variety of oxidation processes.

Axial/Peripheral Chloride/Fluoride-Substituted Boron Subphthalocyanines as Electron Acceptors.

Chloroboron subphthalocyanines (Cl-BsubPc) are robust compounds that can be readily modified at the axial and peripheral positions. Peripherally chlorinated derivatives were recently found to be advantageous regarding integration into organic electronic devices. We now report on the effects of fluorides introduced on both the peripheral and axial positions of BsubPcs.

The Fe(citrate) Fenton reaction under physiological conditions.

The Fenton reaction of Fe(citrate) in the presence and absence of bicarbonate (HCO) is studied. It is found that the rate constant of the Fenton reaction (k) increases with increasing [citrate]. k also increase with increasing [HCO]; this effect is most significant at biological citrate concentrations.

On the Aqueous Chemistry of the U -DOTA Complex.

The 1,4,7,10-tetrazacyclodecane-1,4,7,10-tetraacetic acid (DOTA) aqueous complex of U with H O, OH , and F as axial ligands was studied by using UV/Vis spectrophotometry, ESI-MS, NMR spectroscopy, X-ray crystallography, and electrochemistry. The U -DOTA complex with either water or fluoride as axial ligands was found to be inert to oxidation by molecular oxygen, whereas the complex with hydroxide as an axial ligand slowly hydrolyzed and was oxidized by dioxygen to a diuranate precipitate. The combined data set acquired shows that, although axial substitution of fluoride and hydroxide ligands instead of water does not seem to significantly change the aqueous DOTA complex structure, it has an important effect on the electronic configuration of the complex.

Magnetic properties of (FeMn)AlB and the impact of substitution on the magnetocaloric effect.

In this work, we investigate the magnetic structures of (FeMn)AlB solid-solution quaternaries in the to 1 range using x-ray and neutron diffraction, magnetization measurements, and mean-field theory calculations. While FeAlB and MnAlB are known to be ferromagnetic (FM) and antiferromagnetic (AFM), respectively, herein we focused on the magnetic structure of their solid solutions, which is not well understood. The FM ground state of FeAlB becomes a canted AFM at , with a monotonically diminishing FM component until .

Rhenium(i) sapphyrins: remarkable difference between the CF and CF-substituted derivatives.

Despite sapphyrins being the first ever reported extended porphyrins, their coordination chemistry remains quite limited. The newly gained access to meso-alkyl-substituted sapphyrins encouraged the study of their rhenium chelates in comparison with meso-aryl-substituted derivatives. Both the CF- and CF-substituted sapphyrins act as bidentate/monoanionic ligands, with the coordination sphere of the rhenium(i) ion completed by three carbonyls.

Thermophysical Measurements in Liquid Alloys and Phase Diagram Studies.

Towards the construction of pressure-dependent phase diagrams of binary alloy systems, both thermophysical measurements and thermodynamic modeling are employed. High-accuracy measurements of sound velocity, density, and electrical resistivity were performed for selected metallic elements from columns III to V and their alloys in the liquid phase. Sound velocity measurements were made using ultrasonic techniques, density measurements using the gamma radiation attenuation method, and electrical resistivity measurements were performed using the four probe method.

Cobalt Carbonate as an Electrocatalyst for Water Oxidation.

Co salts in the presence of HCO /CO in aqueous solutions act as electrocatalysts for water oxidation. It comprises of several key steps: (i) A relatively small wave at E ≈0.71 V (vs.

Mechanistic insight into the catalytic inhibition by nitroxides of tyrosine oxidation and nitration.

Background: Nitroxide antioxidants (RNO) protect from injuries associated with oxidative stress. Tyrosine residues in proteins are major targets for oxidizing species giving rise to irreversible cross-linking and protein nitration, but the mechanisms underlying the protective activity of RNO on these processes are not sufficiently clear.

Methods: Tyrosine oxidation by the oxoammonium cation (RN=O) was studied by following the kinetics of RNO formation using EPR spectroscopy.

Tuning Chemical and Physical Properties of Phosphorus Corroles for Advanced Applications.

Although the affinity of metallocorroles to axial ligands is quite low, this is not the case when the chelated element is phosphorus. This work is hence focused on the mechanism of ligand exchange of six-coordinate phosphorus corroles as a tool for affecting their chemical and physical properties. These fundamental investigations allowed for the development of facile methodologies for the synthesis of a large series of complexes and the establishment of several new structure/activity profiles that may be used to understand and predict spectroscopic features and for tailor-made modification of photophysical and electrochemical properties.

Direct Observation of Proton-Neutron Short-Range Correlation Dominance in Heavy Nuclei.

We measured the triple coincidence A(e,e^{'}np) and A(e,e^{'}pp) reactions on carbon, aluminum, iron, and lead targets at Q^{2}>1.5  (GeV/c)^{2}, x_{B}>1.1 and missing momentum >400  MeV/c.

The Initial Stage in Oxidation of ZrNiSn (Half Heusler) Alloy by Oxygen.

The MNiSn (M = Ti; Zr; Hf); half-Heusler semiconducting alloys have a high potential for use as -type thermoelectric materials at elevated temperatures (~1000 K). The alloys' durability is crucial for their commercial handling and use, and therefore it is required to characterize their surface oxidation behavior and stability at the working temperature. X-ray photoelectron spectroscopy was utilized to study the surface composition and oxidation of the ZrNiSn alloy at room and elevated temperatures.

A Tungsten-Based Nanolaminated Ternary Carbide: (W,Ti)C.

Nanolamellar transition metal carbides are gaining increasing interests because of the recent developments of their two-dimensional (2D) derivatives and promising performance for a variety of applications from energy storage, catalysis to transparent conductive coatings, and medicine. To develop more novel 2D materials, new nanolaminated structures are needed. Here we report on a tungsten-based nanolaminated ternary phase, (W,Ti)C, synthesized by an Al-catalyzed reaction of W, Ti, and C powders at 1600 °C for 4 h, under flowing argon.