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851.
Marmuse L Asther M Fabre E Navarro D Lesage-Meessen L Asther M O'Donohue M Fort S Driguez H 《Organic & biomolecular chemistry》2008,6(7):1208-1214
Indolyl and nitrophenyl 5-O-hydroxycinnamoyl-alpha-L-arabinofuranosides were prepared by chemo-enzymatic syntheses. These probes were designed as substrates to be used in assays of feruloyl esterase activity (EC 3.1.1.77). Color development in the assays only occurs when feruloyl esterase activity releases an intermediate chromogenic arabinoside that is a suitable substrate for alpha-L-arabinofuranosidase (EC 3.2.1.55), which in turn releases the free chromogenic group. The usefulness of these compounds was evaluated in both qualitative solid media-based assays and quantitative liquid assays that can be performed in microtiter plates using feruloyl esterases and arabinofuranosidases from various origins. 相似文献
852.
Primes dividing the degrees of the real characters 总被引:1,自引:0,他引:1
Let G be a finite group and let Irr(G) denote the set of all complex irreducible characters of G. The Ito–Michler Theorem asserts that if a prime p does not divide the degree of any χ Irr(G) then a Sylow p-subgroup P of G is normal in G. We prove a real-valued version of this theorem, where instead of Irr(G) we only consider the subset Irrrv(G) consisting of all real-valued irreducible characters of G. We also prove that the character degree graph associated to Irrrv(G) has at most 3 connected components. Similar results for the set of real conjugacy classes of G have also been obtained.
Part of this paper was done while the second author visited the Mathematics Department of the Università di Firenze. He would
like to thank the Department for its hospitality. The authors are also grateful to F. Lübeck for helping them with some computer
calculations.
The research of the first author was partially supported by MIUR research program “Teoria dei gruppi ed applicazioni”. This
research of the second author was partially supported by the Spanish Ministerio de Educación y Ciencia proyecto MTM2004-06067-C02-01.
The third author gratefully acknowledges the support of the NSA and the NSF. 相似文献
853.
Elsa Quartapelle Procopio Tomohiro Fukushima Prof. Dr. Elisa Barea Prof. Dr. Jorge A. R. Navarro Prof. Dr. Satoshi Horike Prof. Dr. Susumu Kitagawa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(41):13117-13125
Herein, the synthesis, crystal structure, and full characterization of a new soft porous coordination polymer (PCP) of ([Cu2(dmcapz)2(OH2)]DMF1.5)n ( 1 ) formulation, which is easily obtained in the reaction of CuX2 (X=Cl, NO3) salts with 3,5‐dimethyl‐4‐carboxypyrazole (H2dmcapz) is present. Compound 1 shows a copper(II) dinuclear secondary building unit (SBU), which is supported by two pyrazolate bridges and an unprecedented H2O bridge. The dinuclear SBUs are further bridged by the carboxylate ligands to build a diamondoid porous network. The structural transformations taking place in 1 framework upon guest removal/uptake has been studied in detail. Indeed, the removal of the bridging water molecules gives rise to a metastable evacuated phase ( 1 b ) that transforms into an extremely stable porous material ( 1 c ) after freezing at liquid‐nitrogen temperature. The soaking of 1 c into water allows the complete and instantaneous recover of the water‐exchanged material ( 1 a′ ). Remarkably, 1 b and 1 c materials possess structural bistability, which results in the switchable adsorptive functions. Therefore, the gas‐adsorption properties of both materials have been studied by means of single‐component gas adsorption isotherms as well as by variable‐temperature pulse‐gas chromatography. Both materials present permanent porosity and selective gas‐adsorption properties towards a variety of gases and vapors of environmental and industrial interest. Moreover, the flexible nature of the coordination network and the presence of highly active convergent open metal sites confer on these materials intriguing gas‐adsorption properties with guest‐triggered framework‐breathing phenomena being observed. The plasticity of CuII metal center and its ability to form stable complexes with different coordination numbers is at the origin of the structural transformations and the selective‐adsorption properties of the studied materials. 相似文献
854.
Julia Romero‐Pastor Natalia Navas Stepanka Kuckova Alejandro Rodríguez‐Navarro Carolina Cardell 《Journal of mass spectrometry : JMS》2012,47(3):322-330
This study focuses on acquiring information on the degradation process of proteinaceous binders due to ultra violet (UV) radiation and possible interactions owing to the presence of historical mineral pigments. With this aim, three different paint model samples were prepared according to medieval recipes, using rabbit glue as proteinaceus binders. One of these model samples contained only the binder, and the other two were prepared by mixing each of the pigments (cinnabar or azurite) with the binder (glue tempera model samples). The model samples were studied by applying Principal Component Analysis (PCA) to their mass spectra obtained with Matrix‐Assisted Laser Desorption/Ionization‐Time of Flight Mass Spectrometry (MALDI‐TOF‐MS). The complementary use of Fourier Transform Infrared Spectroscopy to study conformational changes of secondary structure of the proteinaceous binder is also proposed. Ageing effects on the model samples after up to 3000 h of UV irradiation were periodically analyzed by the proposed approach. PCA on MS data proved capable of identifying significant changes in the model samples, and the results suggested different aging behavior based on the pigment present. This research represents the first attempt to use this approach (PCA on MALDI‐TOF‐MS data) in the field of Cultural Heritage and demonstrates the potential benefits in the study of proteinaceous artistic materials for purposes of conservation and restoration. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
855.
Puértolas B Navlani-García M López JM García T Murillo R Mastral AM Navarro MV Lozano-Castelló D Bueno-López A Cazorla-Amorós D 《Chemical communications (Cambridge, England)》2012,48(52):6571-6573
A highly effective hydrocarbon (HC) trap for the abatement of cold start HC emissions with specific adsorption sites for the different molecules present in the exhaust gases has been designed by means of molecular simulation tools, and later synthesized. 相似文献
856.
Marcelle de Lima Ferreira Bispo Raoni Schroeder Borges Gonçalves Camilo Henrique da Silva Lima Laura Nogueira de Faria Cardoso Maria Cristina Silva Lourenço Marcus Vinícius Nora de Souza 《Journal of heterocyclic chemistry》2012,49(6):1317-1322
Two series of pyrazinamide (PZA) derivatives have been synthesized and evaluated for their in vitro antibacterial activity against Mycobacterium tuberculosis H37Rv. Some compounds exhibited minimum inhibitory concentration activity of 50–100 μg/mL, greater than the first line antituberculosis drug PZA in Alamar Blue assay (>100 μg/mL). The obtained activities can be considered promising results, which characterizes these compounds as good start points to development of new antitubercular agents. 相似文献
857.
Within the diffusion Monte Carlo approach, we have determined the structure of isotopically pure and mixed helium droplets doped with one magnesium atom. For pure (4)He clusters, our results confirm those of Mella et al. [J. Chem. Phys. 123, 054328 (2005)] that the impurity experiences a transition from a surface to a bulk location as the number of helium atoms in the droplet increases. Contrarily, for pure (3)He clusters Mg resides in the bulk of the droplet due to the smaller surface tension of this isotope. Results for mixed droplets are presented. We have also obtained the absorption spectrum of Mg around the 3s3p?(1)P(1) ← 3s(2)?(1)S(0) transition. 相似文献
858.
El-Nahas AM Bozzelli JW Simmie JM Navarro MV Black G Curran HJ 《The journal of physical chemistry. A》2006,110(50):13618-13623
Density functional and ab initio calculations at CBS-QB3 levels of theory were employed with a series of isodesmic reactions to determine the thermochemistry of the 2-oxopropyl or acetonyl radical (CH(3)COC*H2). In turn, this was used to determine formation enthalpies of 2-oxoethyl or formylmethyl (C*H(2)CHO), 2-oxobutyl (C*H(2)COC(2)H(5)), 1-methyl-2-oxopropyl or methylacetonyl (C*H(CH(3))COCH(3)), 1-methyl-2-oxobutyl (C*H(CH(3))COC(2)H(5)), and 3-oxopentyl (C*H(2)CH2COC(2)H(5)). Our computed standard enthalpy of formation of -34.9 +/- 1.9 kJ mol-1 and a resonance stabilization energy of approximately 22 kJ mol(-1) for acetonyl are in good agreement with recent re-determinations, which have indicated a substantial lowering in the long-established value for DeltaH(f)o (298.15 K). A bond dissociation energy of 401 kJ mol(-1) is suggested for the C-H bond in acetone with consistent values for the others. The calculations support the enthalpy of formation of acetaldehyde obtained from combustion experiments of -166.1 kJ mol(-1) rather than the figure of -170.7 kJ mol(-1) extracted from enthalpies of reduction and, in addition, serve to reduce the uncertainty in DeltaH(f)o the 2-oxoethyl radical to +13 +/- 2 kJ mol(-1). 相似文献
859.
Reviriego F Rodríguez-Franco MI Navarro P García-España E Liu-Gonzalez M Verdejo B Domènech A 《Journal of the American Chemical Society》2006,128(51):16458-16459
The sodium salt of the diethyl 1H-pyrazole-3,5-dicarboxylate (2) of amphiphilic character is able to interact with (+)-amphetamine, (+)-methamphetamine, and dopamine, yielding stable complexes. Crystal structure of 2 with (+)-amphetamine leads to a very nice double helical supramolecular structure. 相似文献
860.
Masciocchi N Galli S Sironi A Cariati E Galindo MA Barea E Romero MA Salas JM Navarro JA Santoyo-Gonzalez F 《Inorganic chemistry》2006,45(19):7612-7620
Thermally robust materials of the M(5-X-pyrimidin-2-olate)2 type [M = Co, X = Cl (1(Cl)), X = Br (1(Br)), X = I (1(I)); M = Zn, X = Cl (2(Cl)), X = Br (2(Br)), X = I (2(I))] have been synthesized. Their X-ray powder diffraction structural characterization has revealed that they crystallize as I2d diamondoid frameworks, isomorphous to those of the pristine [M(pyrimidin-2-olate)2]n analogues (1(H), M = Co; 2(H), M = Zn). The magnetic measurements of the 1(X) series at magnetic fields of 100, 300, and 5000 Oe reveal a weak ferromagnetic ordering taking place below the Néel temperature (T(N) approximately 20 K), arising from spin canting phenomena of the antiferromagnetically coupled cobalt centers. Moreover, magnetic hysteresis studies carried out on the 1(X) series at 2 K reveal a strong dependence of both the coercive field H(coer) (2500, 1000, 775, and 500 Oe for 1(Br), 1(Cl), 1(I), and 1(H), respectively) and the remnant magnetization M(rem) (0.0501 mu(B) for 1(Br) and 1(Cl), 0.0457 mu(B) for 1(I), and 0.0358 mu(B) for 1(H)) on the 5-substituent of the pyrimidin-2-olates. The molecular alloys [Co(5-Y-pyrimidin-2-olate)2] (Y = Cl/Br, 1(Cl/Br)) and [Co(5-Y'-pyrimidin-2-olate)2] (Y' = Br/I, 1(Br/I)) have also been prepared and characterized, proving that they have intermediate properties. These materials combine interesting functional properties, such as chemical inertness, magnetism, photoluminescence, and (although weak) SHG activity. 相似文献