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51.
Abdelmalik Moujahid Alicia d’Anjou Blanca Cases 《Chaos, solitons, and fractals》2012,45(9-10):1171-1179
This work analyzes the problem of community structure in real-world networks based on the synchronization of nonidentical coupled chaotic Rössler oscillators each one characterized by a defined natural frequency, and coupled according to a predefined network topology. The interaction scheme contemplates an uniformly increasing coupling force to simulate a society in which the association between the agents grows in time. To enhance the stability of the correlated states that could emerge from the synchronization process, we propose a parameterless mechanism that adapts the characteristic frequencies of coupled oscillators according to a dynamic connectivity matrix deduced from correlated data. We show that the characteristic frequency vector that results from the adaptation mechanism reveals the underlying community structure present in the network. 相似文献
52.
Dr. Natalia Busto Jesús Valladolid Cristina Aliende Prof. Félix A. Jalón Prof. Blanca R. Manzano Dr. Ana M. Rodríguez Prof. Jorge F. Gaspar Celia Martins Dr. Tarita Biver Dr. Gustavo Espino Prof. José María Leal Prof. Begoña García 《化学:亚洲杂志》2012,7(4):788-801
The reactions of two diaminotriazine ligands 2,4‐diamino‐6‐(2‐pyridyl)‐1,3,5‐triazine (2‐pydaT) and 6‐phenyl‐2,4‐diamino‐1,3,5‐triazine (PhdaT) with ruthenium–arene precursors led to a new family of ruthenium(II) compounds that were spectroscopically characterized. Four of the complexes were cationic, with the general formula [(η6‐arene)Ru(κ2‐N,N‐2‐pydaT)Cl]X (X=BF4, TsO; arene=p‐cymene: 1.BF4 , 1.TsO arene=benzene: 2.BF4 , 2.TsO ). The neutral cyclometalated complex [(η6‐p‐cymene)Ru(κ2‐C,N‐PhdaT*)Cl] ( 3 ) was also isolated. The structures of complexes 2.BF4 and 3.H2O were determined by X‐ray diffraction. Complex 1.BF4 underwent a partial reversible‐aquation process in water. UV/Vis and NMR spectroscopic measurements showed that the reaction was hindered by the addition of NaCl and was pH‐controlled in acidic solution. At pH 7.0 (sodium cacodylate) Ru–Cl complex 1.BF4 was the only species present in solution, even at low ionic strength. However, in alkaline medium (KOH), complex 1.BF4 underwent basic hydrolysis to afford a Ru–OH complex ( 5 ). Fluorimetric studies revealed that the interaction of complex 1.BF4 with DNA was not straightforward; instead, its main features were closely linked to ionic strength and to the [DNA]/complex ratio. The bifunctional complex 1.BF4 was capable of interacting concurrently through both its p‐cymene and 2‐pydaT groups. Cytotoxicity and genotoxicity studies showed that, contrary to the expected behavior, the complex species was biologically inactive; the formation of a Ru–OH complex could be responsible for such behavior. 相似文献
53.
Felipe Gómez-de la Torre Yolanda Gutiérrez Félix A. Jalón Blanca R. Manzano Ana Rodríguez 《Monatshefte für Chemie / Chemical Monthly》2000,35(5):1267-1280
Partial removal of chloride anions from the dimer [Pd(η3-2-CH3*C3H4)(μ-Cl)]2 with AgTf(Tf = CF3SO3) followed by addition of dppm affords [Pd2(η3-Me*C3H4)2(μ-Cl)(μ-dppm)]Tf (1). The substitution of Cl− by X− (X = pz, SC6F5, S py ) using the appropriate salts yields the new derivatives [Pd2(η3-Me*C3H4)2(μ-X)(μ-dppm)]Tf (2–4). All complexes exhibit a dinuclear half-A-frame structure with two isomers present in solution. The isomers differ in the relative orientation of the two allyl groups (cis or trans). The isomer interconversion was studied by variable temperature 1H NMR spectroscopy. The molecular structures of 2 and 4 were solved by X-ray diffraction studies. A distorted boat conformation of the seven- or six-membered metallacycle was found in both cases. 相似文献
54.
55.
Alejandra Bermúdez-Oria Yougourthane Bouchal frica Fernndez-Prior Blanca Vioque Juan Fernndez-Bolaos 《Molecules (Basel, Switzerland)》2020,25(24)
The natural antioxidant hydroxytyrosol (HT) was used to functionalize a strawberry puree. The effect of the antioxidant on the stability of the two bioactive forms of vitamin C (ascorbic acid-AA and dehydroascorbic acid-DHAA) in strawberry puree stored at 4 °C, compared with the effect on a model system of AA in water, was investigated. In the absence of HT, the concentration of vitamin C in strawberry puree decreased but not in the model system. Low concentrations of HT in strawberry puree (0.05 and 0.1 mg HT/g puree) stabilized vitamin C and improved its antioxidant activity. However, at high concentrations of HT (from 0.5 mg HT/g puree), although the antioxidant activity improved, degradation of vitamin C occurred. Therefore, the concentration of HT used to obtain a functionalized strawberry puree it is very important. An adequate concentration increases the antioxidant activity and protects vitamin C from degradation, developing a functional food. However, an inadequate concentration of HT affects the vitamin C content, which is essential for the human diet because it cannot be biosynthetized by the organism. 相似文献
56.
Cristina Yagüe Igor Echevarría Dr. Mónica Vaquero Jairo Fidalgo Dr. Arancha Carbayo Dr. Félix A. Jalón Dr. João C. Lima Dr. Artur J. Moro Dr. Blanca R. Manzano Dr. Gustavo Espino 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(53):12219-12232
Five new RuII polypyridyl complexes bearing N-(arylsulfonyl)-8-amidoquinolate ligands and three of their biscyclometalated IrIII congeners have been prepared and employed as photocatalysts ( PC s) in the photooxidation of benzylamines with O2. In particular, the new RuII complexes do not exhibit photoluminescence, rather they harvest visible light efficiently and are very stable in solution under irradiation with blue light. Their non-emissive behavior has been related to the low electrochemical energy gaps and rationalized on the basis of theoretical calculations (DFT analysis) that predict low S0←T1 energy values. Moreover, the RuII complexes, despite being non-emissive, display excellent activities in the selective photocatalytic transformation of benzylamines into the corresponding imines. The presence of an electron-withdrawing group (-CF3) on the arene ring of the N-(arylsulfonyl)-8-amidoquinolate ligand improves the photocatalytic activity of the corresponding photocatalyst. Furthermore, all the experimental evidence, including transient absorption spectroscopy measurements suggest that singlet oxygen is the actual oxidant. The IrIII analogues are considerably more photosensitive and consequently less efficient photosensitizers ( PS s). 相似文献
57.
Blanca Climent-Ezquerra Francisco Guillén-González Marko Rojas-Medar 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2006,51(10):984-998
In this paper we prove existence of weak solution with the reproductivity in time property, for a penalized PDE’s system related
to a nematic liquid crystal model.
This problem is relatively explict when time-independent Dirichlet boundary conditions are imposed for the orientation of
crystal molecules. Nevertheless, for the time-dependent case, the treatment of the problem is completely different. The verification
of a maximum principle for weak reproductive solutions is fundamental in the argument. 相似文献
58.
Design and synthesis of new carbohydrate-lithocholic acid conjugates linked via 1,2,3-triazole rings
Claudia I. Bautista-Hernández Guillermo E. Negrón-Silva Rosa Santillán Blanca Ivonne Vergara-Arenas Deyanira Ángeles-Beltrán Leticia Lomas-Romero Diego Pérez-Martínez 《Tetrahedron》2018,74(16):2009-2019
In this work, we report the synthesis of a novel carbohydrate-lithocholic acid conjugate linked through of 1,2,3-triazole rings and its derivatives in good to excellent yields. The conjugate was synthesized via copper-catalyzed azide?alkyne cycloaddition (CuAAC) from methyl 4,6-O-benzylidene-2,3-di-O-propargyl-α-d-glucopyranoside and methyl 3-azidolithocholate. The structures of all new compounds were properly characterized by infrared (IR), high-resolution mass spectroscopy (HRMS) and one- and two-dimensional nuclear magnetic resonance (NMR). 相似文献
59.
Barberá J Gimeno N Monreal L Piñol R Ros MB Serrano JL 《Journal of the American Chemical Society》2004,126(23):7190-7191
The synthesis and characterization of reactive banana-shaped compounds have been carried out, and their ability to be photopolymerized in their SmCP mesophase has been assessed. The presence of a SmCP liquid crystalline phase in these compounds has been confirmed by X-ray studies. The polymerization of these molecules has been demonstrated by calorimetric techniques as well as by the preparation and characterization of SmCP-ordered free films that are mechanically stable at room temperature. Furthermore, polymerized films exhibit second harmonic generation activity at room temperature in the absence of an electric field. 相似文献
60.
Blanco-Fuente H Esteban-Fernández B Blanco-Méndez J Otero-Espinar FJ 《Chemical & pharmaceutical bulletin》2002,50(1):40-46
Carbomers are carboxyvinylic derivatives that are widely used in the manufacture of hydrogel dosage forms. Because of their anionic nature and large number of acid groups, they tend to interact with cationic substances, and with other hydrophilic polymers containing alcohol groups. Here, we report a study of interactions between the carbomer Carbopol and the cationic drug propranolol hydrochloride in the solid state and in solution, and of the effects of such interactions on the properties of the hydrogel. We found that the drug forms an insoluble ionic complex with the polymer, modifying all of the hydrogel properties studied (swelling, release, bioadhesion). The inclusion of beta-cyclodextrin in the formulation reduces polymer/drug interactions, so that hydrogel properties remain unchanged. This is probably attributable to formation of inclusion complexes of beta-cyclodextrin and the drug, so that the drug is prevented from interacting with the polymer. 相似文献