Low resistance Cu[3]Ge compounds formation by the lowtemperature treatment of Cu/Ge system in atomic hydrogen

The research deals with the regularities for Cu[3]Ge compound formation under the low temperature treatment of a double-layer Cu/Ge system deposited on i-GaAs substrate in atomic hydrogen flow. The treatment of a Cu/Ge/i-GaAs system with layer thicknesses, respectively, of 122 and 78 nm, in atomic hydrogen with a flow rate of 10{15} at.·сm{-2} s{-1} for a duration of 2.5{-10} min at room temperature, leads to an interdiffusion of Cu and Ge and formation of a polycrystalline film containing stoichiometric phase Cu[3]Ge. The film consists of vertically oriented grains of dimensions 100-150 nm and has a minimum specific resistance of 4.5 [mu omega] сm. Variation in the treatment duration of Cu/Ge/i-GaAs samples in atomic hydrogen affects Cu and Ge distribution profiles, the phase composition of films formed, and the specific resistance of the latter. As observed, Cu3Ge compound synthesis at room temperature demonstrates the stimulative effects characteristic of atomic hydrogen treatment for both Cu and Ge diffusion and for the chemical reaction of Cu[3]Ge compound generation. Activation of these processes can be conditioned by the energy released during recombination of hydrogen atoms adsorbed on the surface of a Cu/Ge/i-GaAs sample

Use of the macrocyclic ligand cucurbit[6]uril for isolation of tetranuclear lanthanide aquahydroxo-carboxylate complexes from aqueous solutions

The tetranuclear lanthanide complexes {[Ln4(μ3-OH) 4(μ2-OH)2(C5NH 4COO)2 (H2O)4-(C36H 36N24O12)2][Ln(H2O) 8]1.5[Ln(H2O)6(NO3) 2]0.5} (NO3)9•nH2O (Ln = Ho, Gd, or Er) were prepared by heating (130 °C) aqueous solutions of lanthanide nitrates, cucurbit[6]uril (C36H36N 24O12), and 4-cyanopyridine. The tetradentate coordination of the macrocyclic cucurbit[6]uril ligands through the portals leads to the formation of sandwich compounds, in which the tetranuclear hydroxo complex is located between two macrocyclic molecules. The polynuclear complexes are additionally stabilized by the chelating effect of the isonicotinate ligands generated by hydrolysis of 4-cyanopyridine. In the complexes, the aromatic moiety of the isonicotinate ion is encapsulated into the hydrophobic inner cavity of cucurbit[6]uril. In the absence of cucurbit[6]uril, the reaction with 4-cyanopyridine produces only the polymeric complexes [Nd(C5NH 4COO)3(H2O)2] and [Ln(C 5NH4COO)2(H2O)4]NO 3 (Ln = Pr, Sm, or Gd), whose structures were established by X-ray diffraction. In water and aqueous solutions of nonionic and cationic surfactants, irreversible changes of the tetranuclear fragment of the complex (Ln = Gd) were observed after storage for two days, whereas the anionic surfactant stabilizes the complexes. © 2006 Springer Science+Business Media, Inc

Photoswitching of a thermally unswitchable molecular magnet Cu(hfac) 2Li-Pr evidenced by steady-state and time-resolved electron paramagnetic resonance

Most photoswitchable molecular magnets exhibit thermally induced switching, as is typical of spin crossover (SCO), valence tautomerism and SCO-like phenomena. We report a rare case of a copper-nitroxide based molecular magnet Cu(hfac)2Li-Pr that does not exhibit quantitative SCO-like behavior in the temperature range of its chemical stability (2-350 K); however, it can be switched to a metastable thermally inaccessible spin state via visible/near-IR light at cryogenic temperatures. By means of photogeneration, unique information on this otherwise unobservable spin state has been obtained using steady-state Q-band (34 GHz) and time-resolved W-band (94 GHz) electron paramagnetic resonance (EPR) spectroscopy. In particular, we have found that the electronic structure and relaxation properties of the photoinduced state in Cu(hfac)2Li-Pr are very similar to those in its sister compound Cu(hfac)2Ln-Pr that is thermally switchable and has been exhaustively characterized by many analytical methods, previously. The first observation of photoswitchable behavior in a thermally unswitchable copper-nitroxide based molecular magnet Cu(hfac)2Li-Pr paves the way for photoswitching applications of this and similar compounds in the remarkably broad temperature range of 2-350 K. © 2014 American Chemical Society

Heterospin complex showing spin transition at room temperature

© 2015 Elsevier Ltd. All rights reserved. New nitronyl nitroxides LMe and LMe-CP containing a 4-methylpyridin-3-yl substituent were synthesized. It was found that the interaction of Cu(hfac)2 with LMe and LMe-CP gave binuclear [Cu(hfac)2LMe]2 and [Cu(hfac)2LMe-CP]2·Solv (Solv = n-C6H14, n-C10H22, n-C16H34) and chain polymer {[[Cu(hfac)2]2LMe2][Cu(hfac)2]}∞ heterospin complexes. An important structural peculiarity of LMe and LMe-CP is a large dihedral angle between the planes of the O•-N-CN → O paramagnetic fragment and the pyridine ring: 55.2 and 56.1°, respectively. The presence of a methyl group in the pyridine ring of the nitroxide molecule in {[[Cu(hfac)2]2LMe2][Cu(hfac)2]}∞ proved favorable for spin transition at nearly room temperature

Mechanisms of trematodiases pathogenicity: the presence of the secretory proteins from the liver fluke Opisthorchis felineus in the gallbladder tissues of the patients with chronic opisthorchiasis

Opisthorchiasis caused by the liver fluke Opisthorchis felineus infection remains a serious public health problem in the former USSR and Eastern European countries. O. felineus infests the bile ducts, the liver and gallbladder of many fish-eating mammalian species, including humans. Opisthorchiasis leads to a number of related diseases of the liver and pancreas: liver fibrosis, cholangitis, cholecystitis, liver cysts and pancreatitis. Excretory-secretory products of the parasite are considered to be key factors in host-parasite relationships and mediate pathogenic pleiotropic effects on the host organism.The aim of this study was to determine the helminthic proteins (thioredoxin peroxidase and glutathione-S-transferase) in the gallbladder tissues of the experimental animals and patients with opisthorchiasis disease. We demonstrated by immunohistochemistry assay using antibodies against recombinant O. felineus proteins that thioredoxin peroxidase and glutathione-S-transferase could be detected in the biliary duct epithelium of the experimental animals and in human gallbladder tissues. Moreover, these proteins could also be detected in human gallbladder infiltrated cells and underlying connective tissues. The results are important for understanding the molecular mechanisms of opisthorchiasis pathogenesis, as well as for improvement of the immunodiagnostics of the opisthorchiasis and opisthorchiasis-related diseases

Synthesis and study of Cu^II complex with nitroxide, a jumping crystal analog

© 2017, Springer Science+Business Media, LLC. We synthesized 1-ethylimidazolyl-substituted nitronyl nitroxides, i.e., 2-(1-ethylimidazol-4-yl)- (L 4Et ) and 2-(1-ethylimidazol-5-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole 3-oxide-1-oxyl (L 5Et ). The stable radical L 5Et is an ethyl analog of 2-(1-methylimidazol-5-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole 3-oxide-1-oxyl (L 5Me ) described earlier, the reaction of which with Cu(hfac) 2 (hfac is 1,1,1,5,5,5-hexafluoropentane-2,4-dionate) leads to the formation of the [Cu(hfac) 2 (L 5Me ) 2 ] jumping crystals. The reaction of Cu(hfac) 2 with L 5Et with reagent ratios 1: 2 and 1: 1 yields heterospin complexes [Cu(hfac) 2 (L 5Et ) 2 ] and [Cu(hfac) 2 L 5Et ] 2 , respectively. X-ray diffraction study of the mononuclear complex [Cu(hfac) 2 (L 5Et ) 2 ] determined that the compound has a packing similar to that of jumping crystals studied earlier, with the only difference being that the O..O contacts between neigh- boring nitroxide groups were found to be 0.3—0.5 Å longer than in [Cu(hfac) 2 (L 5Me ) 2 ]. As a result of the lengthening of these contacts, [Cu(hfac) 2 (L 5Et ) 2 ] crystals lack chemomechanical activi- ty. We found that when cooling crystals of binuclear complex [Cu(hfac) 2 L 5Et ] 2 below 50 K, the antiferromagnetic exchange between unpaired electrons of the > N—•O groups of neighboring molecules leads to the full spin-pairing of the nitroxides, with only the Cu 2+ ions contributing to the residual paramagnetism of the compound

Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table, submitted to European Physical Journal

Hunt for new phenomena using large jet multiplicities and missing transverse momentum with ATLAS in 4.7 fb−1 of s√=7TeV proton-proton collisions

Results are presented of a search for new particles decaying to large numbers of jets in association with missing transverse momentum, using 4.7 fb−1 of pp collision data at s√=7TeV collected by the ATLAS experiment at the Large Hadron Collider in 2011. The event selection requires missing transverse momentum, no isolated electrons or muons, and from ≥6 to ≥9 jets. No evidence is found for physics beyond the Standard Model. The results are interpreted in the context of a MSUGRA/CMSSM supersymmetric model, where, for large universal scalar mass m 0, gluino masses smaller than 840 GeV are excluded at the 95% confidence level, extending previously published limits. Within a simplified model containing only a gluino octet and a neutralino, gluino masses smaller than 870 GeV are similarly excluded for neutralino masses below 100 GeV