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81.
Pellei M Papini G Trasatti A Giorgetti M Tonelli D Minicucci M Marzano C Gandin V Aquilanti G Dolmella A Santini C 《Dalton transactions (Cambridge, England : 2003)》2011,40(38):9877-9888
New nitroimidazole and glucosamine conjugated heteroscorpionate ligands, namely 2,2-bis(3,5-dimethyl-1H-pyrazol-1-yl)-N-(2-(2-methyl-5-nitro-1H-imidazol-1-yl)ethyl)acetamide (L(MN)) and 1,3,4,6-tetra-O-acetyl-2-{[bis(3,5-dimethyl-1H-pyrazol-1-yl)acetyl]amino}-2-deoxy-β-D-glucopyranose (L(DAC)), respectively, were synthesized by direct coupling of preformed side chain acid and amine components. The related copper(II) complexes {[(L(MN))(2)Cu]Cl(2)}, and {[(L(DAC))(2)Cu]Cl(2)} have been prepared from the reaction of CuCl(2)*2H(2)O with L(MN) or L(DAC) ligand in methanol solution. Single crystal structural characterization was undertaken for the L(MN) ligand. In the absence of a coordinated metal core, the overall arrangement of the ligand is determined by some loose intra- and inter-molecular nonbonding contacts. X-Ray Absorption Spectroscopy (XAS) has been used to probe the local structure of the two copper(II) complexes, {[(L(MN))(2)Cu]Cl(2)} and {[(L(DAC))(2)Cu]Cl(2)}. The EXAFS analysis has permitted the identification of the local environment of the copper site. Copper interacts with 2 units of ligand in both complexes, and it is found to be 6-fold coordinated. Its local structure is described by four Cu-N and two Cu-O interactions to form a pseudo-octahedron core, with a 0.14 ? lengthening of the Cu-O bond length in the case of L(DAC) complex with respect to the L(MN) one, likely due to the higher steric hindrance of the glucosamine moiety. The XANES analysis agrees with these results, also confirming the Cu(II) formal copper oxidation state for both complexes. The new copper(II) complexes {[(L(MN))(2)Cu]Cl(2)} and {[(L(DAC))(2)Cu]Cl(2)} as well as the corresponding uncoordinated ligands were evaluated for their cytotoxic activity towards a panel of several human tumour cell lines. The results reported here indicate that both copper(II) complexes show similar spectra of cytotoxicity and very low resistance factors (RF < 2) against C13* ovarian cancer cells which have acquired resistance to cisplatin. 相似文献
82.
Mixed convection flow in a horizontal rectangular channel subjected to a horizontal thermal gradient
This paper deals with a mixed convection water flow in a horizontal rectangular duct, uniformly heated from one lateral vertical
wall and thermally insulated elsewhere. The supplied heat flux induces a secondary flow, which structure is constituted of
one longitudinal roll in the considered aspect ratio (Γ = 1.9), embedded into a return flow of possibly large stream wise
extension (up to twenty channel heights). Such situation induces helicoidal trajectories for the fluid flow particles, which
contributes to a heat transfer enhancement compared to purely forced convection flow. 相似文献
83.
Adriani O Barbarino GC Bazilevskaya GA Bellotti R Boezio M Bogomolov EA Bongi M Bonvicini V Borisov S Bottai S Bruno A Cafagna F Campana D Carbone R Carlson P Casolino M Castellini G Consiglio L De Pascale MP De Santis C De Simone N Di Felice V Galper AM Gillard W Grishantseva L Jerse G Karelin AV Koldashov SV Krutkov SY Kvashnin AN Leonov A Malakhov V Malvezzi V Marcelli L Mayorov AG Menn W Mikhailov VV Mocchiutti E Monaco A Mori N Nikonov N Osteria G Palma F Papini P Pearce M Picozza P 《Physical review letters》2011,106(20):201101
Precision measurements of the electron component in the cosmic radiation provide important information about the origin and propagation of cosmic rays in the Galaxy. Here we present new results regarding negatively charged electrons between 1 and 625 GeV performed by the satellite-borne experiment PAMELA. This is the first time that cosmic-ray e? have been identified above 50 GeV. The electron spectrum can be described with a single power-law energy dependence with spectral index -3.18 ± 0.05 above the energy region influenced by the solar wind (> 30 GeV). No significant spectral features are observed and the data can be interpreted in terms of conventional diffusive propagation models. However, the data are also consistent with models including new cosmic-ray sources that could explain the rise in the positron fraction. 相似文献
84.
A. M. Galper O. Adriani R. L. Aptekar I. V. Arkhangelskaja A. I. Arkhangelskiy M. Boezio V. Bonvicini K. A. Boyarchuk A. Vacchi E. Vannuccini Yu. V. Gusakov N. Zampa V. G. Zverev V. N. Zirakashvili V. A. Kaplin V. A. Kachanov A. A. Leonov F. Longo E. P. Mazets P. Maestro P. Marrocchesi I. A. Mereminskiy V. V. Mikhailov A. A. Moiseev E. Mocchiutti N. Mori I. V. Moskalenko P. Yu. Naumov P. Papini P. Picozza V. G. Rodin M. F. Runtso R. Sparvoli P. Spillantini S. I. Suchkov M. Tavani N. P. Topchiev M. I. Fradkin M. D. Kheymits Y. T. Yurkin 《Bulletin of the Russian Academy of Sciences: Physics》2013,77(11):1339-1342
The GAMMA-400 gamma-ray telescope currently under development is designed to measure fluxes of gamma rays and electron-positron cosmic-ray components, which could be associated with the annihilation or decay of dark matter particles, and to survey in detail the celestial sphere in order to search for and investigate discrete gamma-ray sources; to measure the energy spectra of Galactic and extragalactic dif- fuse gamma-ray emissions; and to study gamma-ray bursts and the gamma-ray emissions of active Sun. The GAMMA-400 energy range is 100 MeV to 3000 GeV. The gamma-ray telescope has an angular resolution of ~0.01°, an energy resolution of ~1%, and a proton rejection factor of ~106. The GAMMA-400 will be installed on Russia’s Navigator space platform. Observations are planned to commence in 2018. 相似文献
85.
Maestro P. Adriani O. Akaike Y. Asaoka Y. Berti E. Bigongiari G. Bongi M. Brogi P. Bruno A. Cannady N. Checchia C. Cherry M. L. Collazuol G. Guzik T. G. Ichimura M. Israel M. H. Kasahara K. Kawakubo Y. Krizmanic J. F. Marrocchesi P. S. Messineo A. M. Mitchell J. W. Miyake S. Mori M. Mori N. Motz H. M. Munakata K. Pacini L. Palma F. Papini P. Rauch B. F. Ricciarini S. B. Sakamoto T. Sasaki M. Stolzi F. Sulaj A. Tamura T. Torii S. Wefel J. P. Yoshida K. 《Physics of Atomic Nuclei》2019,82(6):766-772
Physics of Atomic Nuclei - The CALorimetric Electron Telescope (CALET) is an astroparticle physics experiment installed on the International Space Station since August 2015. The CALET mission was... 相似文献
86.
The adsorption characteristics of the "Red Soil" with respect to lead were studied as function of different experimental conditions. Lead adsorption was investigated as function of the complexing capacity of the liquid phase (background electrolyte NaClO4, NaCl, CH3COONa e EDTA), pH (experimental range 4-7) and ionic strength (experimental range 0.001-0.35 M), by determining the adsorption isotherms at the different conditions. Experimental results allowed to identify the presence of different sorption sites, acting on lead removal through different mechanisms (ion exchange and surface complexation). These sorption sites are differently affected by changing the experimental conditions. Adsorption representation in terms of free metal was not able to describe the experimental behaviour, especially when different charged species can be formed and might be sorbed at the surface with different affinities. Particular attention was given to the optimisation of the experimental system based on the flow-through reactor set-up, in order to carry out adsorption tests more representative of the field situation. 相似文献
87.
We propose a unified theory of gravitation and electromagnetism which can be applied to charged multiply connected superfluids. It extends the conformally invariant Weyl-Dirac theory to complex gauge fields β and recovers flux quantization as the byproduct of a lagrangian constraint. Superconductors are described as multiply connected regions of space- time through the phase of β. 相似文献
88.
The first 5-substituted trihydro(azolyl)borate system, the sodium trihydro(5-CF3-pyrazol-1-yl)borate, Na[H3B(5-(CF3)pz)], has been synthesized by the reaction of 3-trifuoromethyl-pyrazole with NaBH4 in high yield. Na[H3B(5-(CF3)pz)] reacts with AgNO3 in the presence of monodentate tertiary phosphanes PR3 (PR3=P(C6H5)3, P(p-C6H4CH3)3, P(m-C6H4CH3)3, P(o-C6H4CH3)3, or PCH3(C6H5)2) to afford silver(I) bis(phosphane) adducts. These compounds have been characterized by elemental analyses, FTIR, ESI-MS, and multinuclear (1H, 19F, and 31P) NMR spectroscopy. Solid-state structures of {[H3B(5-(CF3)pz)]Ag[P(C6H5)3]2} and {[H3B(5-(CF3)pz)]Ag[P(p-C6H4CH3)3]2} are also reported. They feature kappa2-N,H-bonded trihydro(pyrazolyl)borate ligands and pseudo-tetrahedral silver atoms. 相似文献
89.
Pellei M Alidori S Papini G Lobbia GG Gorden JD Dias HV Santini C 《Dalton transactions (Cambridge, England : 2003)》2007,(42):4845-4853
New silver(I) complexes have been synthesized from the reaction of AgNO(3), monodentate tertiary phosphanes PR(3) (PR(3) = P(C(6)H(5))(3), P(o-C(6)H(4)CH(3))(3), P(m-C(6)H(4)CH(3))(3), P(p-C(6)H(4)CH(3))(3), PCH(3)(C(6)H(5))(2)) and two novel electron withdrawing ligands: potassium dihydrobis(3-nitropyrazol-1-yl)borate and potassium dihydrobis(3-trifluoromethylpyrazol-1-yl)borate. These compounds have been characterized by elemental analyses, FT-IR, ESI-MS and multinuclear ((1)H, (19)F and (31)P) NMR spectroscopy. Solid state structures of the potassium salts K[H(2)B(3-(NO(2))pz)(2)] and K[H(2)B(3-(CF(3))pz)(2)] have been reported. They form polymeric networks due to intermolecular contacts of various types between the potassium ion and atoms of the neighboring molecules. The silver adducts [H(2)B(3-(NO(2))pz)(2)]Ag[P(C(6)H(5))(3)](2) and [H(2)B(3-(NO(2))pz)(2)]Ag[P(p-C(6)H(4)CH(3))(3)] have pseudo tetrahedral and trigonal planar silver sites, respectively. The bis(pyrazolyl)borate ligand acts as a kappa(2)-N(2) donor. The nitro-substituents are coplanar with the pyrazolyl rings in all these adducts indicating efficient electron delocalization between the two units. The [H(2)B(3-(CF(3))pz)(2)]Ag[P(C(6)H(5))(3)] complex has been obtained from re-crystallization of {[H(2)B(3-(CF(3))pz)(2)]Ag[P(C(6)H(5))(3)](2)} in a dichloromethane-diethyl ether solution; it is a three-coordinate, trigonal planar silver complex. 相似文献