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81.
José Luis Castrejon-Flores Oscar Ernesto Guevara-Moreno Raúl Ricardo Díaz-Contreras Atilano Gutiérrez-Carrillo Marco Franco-Pérez 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):1062-1066
AbstractWe present a multicomponent reaction strategy to synthesize a (dihydro-1H-benzo[d]imidazole)phosphonate family of compounds, using benzimidazoles, diethyl chlorophosphate and aliphatic amines as starting reactants. Giving its simplicity, our procedure involves reaction times of only few hours and avoid the usage of any catalyst agent. All the newly synthesized compounds were characterized by Nuclear Magnetic Resonance spectroscopy (1H, 13C and 31P) and mass spectrometry by the DART method. 相似文献
82.
BedrʼEddine Ainseba Mostafa Bendahmane Ricardo Ruiz-Baier 《Journal of Mathematical Analysis and Applications》2012,388(1):231-247
In the present paper, an optimal control problem constrained by the tridomain equations in electrocardiology is investigated. The state equations consisting in a coupled reaction–diffusion system modeling the propagation of the intracellular and extracellular electrical potentials, and ionic currents, are extended to further consider the effect of an external bathing medium. The existence and uniqueness of solution for the tridomain problem and the related control problem is assessed, and the primal and dual problems are discretized using a finite volume method which is proved to converge to the corresponding weak solution. In order to illustrate the control of the electrophysiological dynamics, we present some preliminary numerical experiments using an efficient implementation of the proposed scheme. 相似文献
83.
Cristiane S. Schwalm Ilton B.D. de Castro Jailton Ferrari Fábio L. de Oliveira Ricardo Aparicio Carlos Roque D. Correia 《Tetrahedron letters》2012,53(13):1660-1663
Pentrabromopseudilin and other 2 and 3-arylpyrrole derivatives were synthesized through the Heck–Matsuda reaction involving endocyclic enecarbamates and N-protected 3-pyrrolines, respectively. The overall processes permitted an easy and efficient access to these structural motifs present in several bioactive compounds. Attempts to synthesize the compound isopentabromopseudilin led to a tribromo aryl maleimide. We hypothesize that this latter compound is the putative product arising from the unusual thermal instability of isopentabromopseudilin. 相似文献
84.
Ren Y Acuña UM Jiménez F García R Mejía M Chai H Gallucci JC Farnsworth NR Soejarto DD Carcache de Blanco EJ Kinghorn AD 《Tetrahedron》2012,68(12):2671-2678
Six new (1-6) and eight known germacranolide-type sesquiterpene lactones, along with several known phenylpropanol coumarates and methylated flavonoids, were isolated from the leaves of Piptocoma rufescens, collected in the Dominican Republic. The new compounds were identified by analysis of their spectroscopic data, with the molecular structure of 3 being established by single-crystal X-ray diffraction. The absolute configurations of the sesquiterpene lactones isolated were determined from their CD and NOESY NMR spectra, together with the analysis of Mosher ester reactions. Bioassay screening results showed the majority of the sesquiterpene lactones isolated (1-13) to be highly cytotoxic toward the HT-29 human colon cancer cell line, with the most potent compound being 15-deoxygoyazensolide (10, IC(50), 0.26 μM). In addition, several of the sesquiterpene lactones exhibited NF-κB (p65) inhibitory activity. 相似文献
85.
Ricardo de Aldama 《Mathematical Logic Quarterly》2013,59(3):201-205
We prove that in a group without the independence property a nilpotent subgroup is always contained in a definable nilpotent subgroup of the same nilpotency class. The analogue for the soluble case is also shown when the subgroup is normal in the ambient group. 相似文献
86.
87.
Ricardo ABREU-BLAYA Juan BORY-REYES Fred BRACKX Hennie DE SCHEPPER Frank SOMMEN 《数学学报(英文版)》2012,(11)
A Hilbert transform for Hlder continuous circulant (2 × 2) matrix functions, on the d-summable (or fractal) boundary Γ of a Jordan domain Ω in R2n , has recently been introduced within the framework of Hermitean Clifford analysis. The main goal of the present paper is to estimate the Hlder norm of this Hermitean Hilbert transform. The expression for the upper bound of this norm is given in terms of the Hlder exponents, the diameter of Γ and a specific d-sum (d d) of the Whitney decomposition of Ω. The result is shown to include the case of a more standard Hilbert transform for domains with left Ahlfors-David regular boundary. 相似文献
88.
One of the most common environmental impacts of road transportation is the traffic noise. Linked to this, Start/Stop is a technology which has demonstrated to save fuel by powering off the engine when the vehicle is stopped, such as in front of a traffic light, and restarting the engine instantly when the driver pushes back the pedal brake to proceed. The technology helps also to reduce the CO2 emission, playing a key role in a way to accomplish stringent emission norms for vehicle manufacturer. However, we are not sure whether it reduces the noise emission and how much? Thus, the main aim of this work is to assess the engine noise emissions of a vehicle incorporating a Start/Stop system in urban traffic, and compare it with those radiated by the mean traffic stream. Experimental results demonstrate that there are no contributions of the Start/Stop system to reduce meaningfully the engine noise in urban traffic. 相似文献
89.
90.
Heloisa Beraldo Ricardo F. F. da Costa Rejane Lima Geraldo M. de Lima Ivana S. Lula Bernard Mahieu 《Phosphorus, sulfur, and silicon and the related elements》2013,188(10):2455-2463
The reaction of tin(IV) tetrachloride with 3-formylpyridine semicarbazone and different 3-formylpyridine thiosemicarbazones produces [Sn(HL)CL 3 ][SnCl 5 ] where HL stands for the neutral ligand. The tin(IV) complexes were characterized using a variety of spectroscopic techniques. Coordination through the pyridine nitrogen occurs in all cases. Solvation studies in DMSO indicated that dissociation of the ligands and their complete replacement by solvent molecules occurs. 相似文献