H multiple quantum NMR in alternating quasi-one-dimensional spin chains of hambergite.

Multiple quantum (MQ) dynamics was investigated in quasi-one-dimensional H zigzag spin chains in hambergite (BeBOOH) single crystals. Due to the non-linear arrangement of the spins, dipolar coupling strengths alternate along the chain. To solve the problem of MQ NMR experiments taking too much time due to extremely long H spin-lattice relaxation times, the samples were exposed to gamma irradiation to produce the defects accelerating the relaxation.

Polymer Electrolytes Based on Na-Nafion Plasticized by Binary Mixture of Ethylene Carbonate and Sulfolane.

The development of post-lithium current sources, such as sodium-ion batteries with improved energy characteristics and an increased level of safety, is one of the key issues of modern energy. It requires the search and study of materials (including electrolytes) for these devices. Polyelectrolytes with unipolar cationic conductivity based on Nafion membranes are promising.

Synthesis of NiAl Intermetallic Compound under Shock-Wave Extrusion.

This paper presents the implementation of the first stage of a study on the synthesis of the intermetallic compound in the Ni-Al system under shock-wave extrusion (SWE). A method was developed and experiments involving SWE of the reactive Ni-Al powder mixture were carried out. As a result, it was possible to obtain up to 56 vol.

Electrochemical Improvement of the MWCNT/Al Electrodes for Supercapacitors.

An original technique of chemical deposition (CVD) by catalytic pyrolysis of ethanol vapor was used to directly grow multiwall carbon nanotubes (MWCNTs) layers on aluminum foil. The grown nanotubes had excellent adhesion and direct electrical contact to the aluminum substrate. This material was perfect for use in electrochemical supercapacitors.

Towards the design of molecular cells for quantum cellular automata: critical reconsideration of the parameter regime for achieving functionality.

In this article, we present a critical discussion of the parametric regimes required for reaching the functionality of the two-electron square-planar tetrameric mixed-valence (MV) complexes as molecular cells in quantum cellular automata (QCA). Previous studies on molecular QCA were restricted by the limit case of strong Coulomb interaction that was supposed to be the only way to ensure such two key requirements for functioning QCA cells as bistability and switchability. It was thus assumed that the site-to-site electron transfer energy should be much smaller than the energy of the Coulomb repulsion between the two excess electrons (strong- limit defined by the inequality ≫ ).

The Phosphonate Derivative of C Fullerene Induces Differentiation towards the Myogenic Lineage in Human Adipose-Derived Mesenchymal Stem Cells.

Inductors of myogenic stem cell differentiation attract attention, as they can be used to treat myodystrophies and post-traumatic injuries. Functionalization of fullerenes makes it possible to obtain water-soluble derivatives with targeted biochemical activity. This study examined the effects of the phosphonate C fullerene derivatives on the expression of myogenic transcription factors and myogenic differentiation of human mesenchymal stem cells (MSCs).

Evolution of Ferromagnetic and Antiferromagnetic States in Iron Nitride Clusters FeN and FeN ( = 1-10).

First-principles density functional theory calculations on neutral and singly negatively and positively charged iron clusters Fe and iron nitride clusters FeN and FeN ( = 1-10) in the range of 1 ≤ ≤ 10 revealed that there is a strong competition between ferromagnetic and antiferromagnetic states especially in the FeN cluster series. This phenomenon was related to superexchange via a bridging N atom between two iron atoms in the FeN cluster series and to a double superexchange effect via a Fe atom shared by two N atoms in the FeN series. A thorough examination of the structure-energy-spin state relationships in these clusters is conducted, leading to new insights and confirmation of available experimental results on structural parameters and dissociation energetics.

Insight Into The Spin-Vibronic Problem of a Mixed Valence Magnetic Molecular Cell for Quantum Cellular Automata.

The effects of the vibronic coupling in quantum cellular automata (QCA) based on the square planar mixed valence (MV) molecular cells comprising four paramagnetic centers (spin cores) and two excess mobile electrons are analyzed in the important particular case when the Coulomb energy gap between the ground antipodal diagonal-type two-electron configurations and the excited side-type configurations considerably exceeds both the one-electron transfer parameter (strong U-limit) and the vibronic stabilization energy. Under such conditions the developed model involves the second-order double exchange, the Heisenberg-Dirac-Van Vleck (HDVV) exchange and the vibronic coupling of the excess electrons with the molecular B -vibration composed of four full-symmetric local vibrations. The latter interaction is shown to significant amplify the ability of the electric field produced by the driver-cell to polarize the excess electrons in the working cell, which can be termed "the effect of the vibronic enhancement of the cell-cell interaction".

Changes in Surface Free Energy and Surface Conductivity of Carbon Nanotube/Polyimide Nanocomposite Films Induced by UV Irradiation.

Changes in surface energy and electrical conductivity of polyimide (PI)-based nanocomposite films filled with carbon nanotubes (CNTs) induced by UV exposure are gaining considerable interest in microelectronic, aeronautical, and aerospace applications. However, the underlying mechanism of PI photochemistry and oxidation reactions induced by UV irradiation upon the surface in the presence of CNTs is still not clear. Here, we probed the interplay between CNTs and PIs under UV exposure in the surface properties of CNT/PI nanocomposite films.

De Novo Transcriptome Profiling of Brain Tissue from the Annual Killifish .

is a genus of small annual killifish found in Africa. Due to the relatively short lifespan, as well as easy breeding and care, fish are becoming widely used as a vertebrate model system. Studying the genome and transcriptome of these fish is essential for advancing the field.

New Multifunctional Agents Based on Conjugates of 4-Amino-2,3-polymethylenequinoline and Butylated Hydroxytoluene for Alzheimer's Disease Treatment.

New hybrids of 4-amino-2,3-polymethylenequinoline with different sizes of the aliphatic ring linked to butylated hydroxytoluene (BHT) by enaminoalkyl () or aminoalkyl () spacers were synthesized as potential multifunctional agents for Alzheimer's disease (AD) treatment. All compounds were potent inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) with selectivity toward BChE. Lead compound , 2,6-di--butyl-4-{[2-(7,8,9,10- tetrahydro-6H-cyclohepta[b]quinolin-11-ylamino)-ethylimino]-methyl}-phenol exhibited an IC(AChE) = 1.

Delving into Autocatalytic Liquid-State Thermal Decomposition of Novel Energetic 1,3,5-Triazines with Azido, Trinitroethyl, and Nitramino Groups.

Thermal decomposition of 1,3,5-triazines with azido, trinitroethyl, and nitramino groups, the three important energetic functionalities, has been studied with a range of thermal analysis tools. The involved compounds melt under heating with the following mass loss and heat and gas release in the course of thermal decomposition. Model-fitting kinetic analysis resulted in formal reaction schemes with two general stages.

Dissociation of Singly and Multiply Charged Nitromethane Cations: Femtosecond Laser Mass Spectrometry and Theoretical Modeling.

Dissociation pathways of singly- and multiply charged gas-phase nitromethane cations were investigated with strong-field laser photoionization mass spectrometry and density functional theory computations. There are multiple isomers of the singly charged nitromethane radical cation, several of which can be accessed by rearrangement of the parent CH-NO structure with low energy barriers. While direct cleavage of the C-N bond from the parent nitromethane cation produces NO and CH, rearrangement prior to dissociation accounts for fragmentation products including NO, CHOH, and CHNO.

Effects of Functionalized Fullerenes on ROS Homeostasis Determine Their Cytoprotective or Cytotoxic Properties.

Background: Functionalized fullerenes (FF) can be considered regulators of intracellular reactive oxygen species (ROS) homeostasis; their direct oxidative damage-as well as regulation of oxidant enzymes and signaling pathways-should be considered.

Methods: Uptake of two water-soluble functionalized C fullerenes with different types of aromatic addends (ethylphenylmalonate and thienylacetate) in human fetal lung fibroblasts, intracellular ROS visualization, superoxide scavenging potential, NOX4 expression, NRF2 expression, oxidative DNA damage, repair genes, cell proliferation and cell cycle were studied.

Results & Conclusion: The intracellular effects of ethylphenylmalonate C derivative (FF1) can be explained in terms of upregulated NOX4 activity.

From Neutral Aniline to Aniline Trication: A Computational and Experimental Study.

We report density functional theory computations and photoionization mass spectrometry measurements of aniline and its positively charged ions. The geometrical structures and properties of the neutral and singly, doubly, and triply positively charged aniline are computed using density functional theory with the generalized gradient approximation. At each charge, there are multiple isomers closely spaced in total energy.

Polymer Electrolytes for LIBs Based on Perfluorinated Sulfocationic Nepem-117 Membrane and Aprotic Solvents.

Polymer electrolytes have been obtained by using Nepem-117 membranes in a Li form intercalated by polar aprotic solvents, such as dimethylformamide, dimethyl sulfoxide (DMSO), and dimethylacetamide (DMA), and solvent mixtures, such as ethylene carbonate-propylene carbonate (EC-PC), EC-DMA, EC-PC-DMA, and EC-PC-DMA-tetrahydrofuran. The obtained electrolytes have been characterized by IR impedance and Li pulsed field gradient NMR spectroscopy. Ion mobility was observed to increase with higher degrees of solvation of the membranes.

Biomimetic Approach to Inhibition of Photooxidation in Organic Solar Cells Using Beta-Carotene as an Additive.

Recent efficiency records of organic photovoltaics (OPV) highlight stability as a limiting weakness. Incorporation of stabilizers is a desirable approach for inhibiting degradation-it is inexpensive and readily up-scalable. However, to date, such additives have had limited success.

Orientational dependencies of dynamics and relaxation of multiple quantum NMR coherences in one-dimensional systems.

Dynamics and relaxation, or decoherence, of multiple quantum (MQ) coherences are investigated experimentally and theoretically for different orientations of a single crystal of fluorapatite with respect to the external magnetic field. Dynamics of MQ coherences is studied as a function of the preparation period of the MQ NMR experiment. Their relaxation, or decoherence, during the evolution period is also investigated.

Antioxidant Properties of Fullerene Derivatives Depend on Their Chemical Structure: A Study of Two Fullerene Derivatives on HELFs.

Oxidative stress is a major issue in a wide number of pathologies (neurodegenerative, cardiovascular, immune diseases, and cancer). Because of this, the search for new antioxidants is an important issue. One of the potential antioxidants that has been enthusiastically discussed in the past twenty years is fullerene and its derivatives.

2-Hetaryl-1,3-tropolones based on five-membered nitrogen heterocycles: synthesis, structure and properties.

A series of derivatives of 2-hetaryl-1,3-tropolone (β-tropolone) was prepared by the acid-catalyzed reaction of 2-methylbenzoxazoles, 2-methylbenzothiazoles and 2,3,3-trimethylindoline with 3,4,5,6-tetrachloro-1,2-benzoquinone. The molecular structures of the three representative compounds were determined by X-ray crystallography. In crystal and (as shown by the DFT PBE0/6-311+G** calculations) in solution, 2-hetaryl-4,5,6,7-tetrachloro- and 2-hetaryl-5,6,7-trichloro-1,3-tropolones exist in the NH-tautomeric form with a strong resonance-assisted intramolecular N-H···O hydrogen bond.

Steady-state deformation behavior of confined composite droplets under shear flow.

The shear-induced dynamics of two-dimensional composite droplets in a narrow channel is investigated numerically. The droplets consist of a viscous inner droplet (core) and shell immersed in a continuous Newtonian fluid. Attention is focused on studying the effects of confinement at different core-to-shell radii ratios, relative viscosities of the medium components, and interfacial tensions on the steady-state deformation and orientation of a composite droplet.

[70]fullerene-based materials for organic solar cells.

The synthesis, characterization and photovoltaic study of two novel derivatives of [70]fullerene, phenyl-C₇₁-propionic acid propyl ester ([70]PCPP) and phenyl-C₇₁-propionic acid butyl ester ([70]PCPB), are reported. [70]PCPP and [70]PCPB outperform the conventional material (6,6)-phenyl-C₇₁-butyric acid methyl ester ([70]PCBM) in solar cells based on poly(2-methoxy-5-{3',7'-dimethyloctyloxy}-p-phenylene vinylene) (MDMO-PPV) as a donor polymer using chlorobenzene (CB) or dichlorobenzene (DCB) as solvents. AFM data suggest that improvement of the device efficiency should be attributed to the increased phase compatibility between the novel C₇₀ derivatives and the polymer matrix.

The remarkable chemistry of trannulenes: green fluorinated fullerenes with unconventional aromaticity.

We report the first reaction of trannulenes involving their thermal isomerization to a new class of compounds termed "triumphenes". The thermodynamically controlled conversion of trannulenes into triumphenes is accompanied by an unprecedented migration of three organic addends from one hemisphere of the fullerene cage to another. The reaction products, bearing aliphatic substituents, might find applications in materials science as strong electron acceptors due to the presence of fifteen electron-withdrawing fluorine atoms in their molecular framework.

Entanglement of systems of dipolar coupled nuclear spins at the adiabatic demagnetization.

We consider the adiabatic demagnetization in the rotating reference frame (ADRF) of a system of dipolar coupled nuclear spins s = 1/2 in an external magnetic field. The demagnetization starts with the offset of the external magnetic field (in frequency units) from the Larmor frequency being several times greater than the local dipolar field. For different subsystem sizes, we have found from numerical simulations the temperatures at which subsystems of a one-dimensional nine-spin chain and a plane nine-spin cluster become entangled.

Chlorofullerene C60Cl6: a precursor for straightforward preparation of highly water-soluble polycarboxylic fullerene derivatives active against HIV.

We report for the first time the application of chlorofullerene C60Cl6 as a substrate for straightforward preparation of highly water-soluble fullerene derivatives, promising compounds for investigation of the biological action of fullerenes in vitro and in vivo. Methyl esters of phenylacetic and benzylmalonic acids were used as reagents in the Friedel-Crafts arylation of C60Cl6 that resulted in the corresponding C60(Ar)5Cl compounds with 50-60% yields. The following cleavage of ester groups in phenylacetic and benzylmalonic residues was accomplished almost quantitatively to yield the corresponding fullerene-based acids bearing 5 and 10 carboxylic groups, respectively.