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911.
Dr. Pablo Labra-Vázquez Ricardo Flores-Cruz Aylin Galindo-Hernández Dr. Justo Cabrera-González Cristian Guzmán-Cedillo Dr. Arturo Jiménez-Sánchez Dr. Pascal G. Lacroix Dr. Rosa Santillan Dr. Norberto Farfán Dr. Rosario Núñez 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(69):16530-16540
A set of BODIPY-carboranyl dyads synthesized by a Sonogashira cross-coupling reaction, where different C-substituted ortho- and meta-carboranyl fragments have been linked to a BODIPY fluorophore is described. Chemical, photophysical and physicochemical analyses are presented, including NMR and single XRD experiments, optical absorption/emission studies and partition coefficient (log P) measurements. These studies, supported by DFT computations (M06-2X/6-31G**), provide an explanation to the largely divergent cell income that these fluorescent carboranyl-based fluorophores display, for which a structural or physicochemical explanation remains elusive. By studying the cell uptake efficiency and subcellular localization for our set of dyads on living HeLa cells, we tracked the origins of these differences to significant variations in their static dipole moments and partition coefficients, which tune their ability to interact with lipophilic microenvironments in cells. Remarkably, m-carboranyl-BODIPY derivatives with a higher lipophilicity are much better internalised by cells than their homologous with o-carborane, suggesting that m-isomers are potentially better theranostic agents for in vitro bioimaging and boron carriers for boron neutron capture therapy. 相似文献
912.
913.
914.
Raimund Bürger Rosa Donat Pep Mulet Carlos A. Vega 《Journal of computational physics》2011,230(6):2322-2344
The sedimentation of a polydisperse suspension of small rigid spheres of the same density, but which belong to a finite number of species (size classes), can be described by a spatially one-dimensional system of first-order, nonlinear, strongly coupled conservation laws. The unknowns are the volume fractions (concentrations) of each species as functions of depth and time. Typical solutions, e.g. for batch settling in a column, include discontinuities (kinematic shocks) separating areas of different composition. The accurate numerical approximation of these solutions is a challenge since closed-form eigenvalues and eigenvectors of the flux Jacobian are usually not available, and the characteristic fields are neither genuinely nonlinear nor linearly degenerate. However, the flux vectors associated with the widely used models by Masliyah, Lockett and Bassoon (MLB model) and Höfler and Schwarzer (HS model) give rise to Jacobians that are low-rank perturbations of a diagonal matrix. This property allows to apply a convenient hyperbolicity criterion that has become known as the “secular equation” [J. Anderson, A secular equation for the eigenvalues of a diagonal matrix perturbation, Lin. Alg. Appl. 246 (1996) 49–70]. This criterion was recently applied [R. Bürger, R. Donat, P. Mulet, C.A. Vega, Hyperbolicity analysis of polydisperse sedimentation models via a secular equation for the flux Jacobian, SIAM J. Appl. Math. 70 (2010) 2186–2213] to prove that the MLB and HS models are strictly hyperbolic under easily verifiable conditions, that their eigenvalues interlace with the velocities of the species that form the flux vector (so the velocities are good starting values for a root finder), and that the corresponding eigenvectors can be calculated with acceptable effort. In the present work, the newly available characteristic information is exploited for the implementation of characteristic-wise (spectral) weighted essentially non-oscillatory (WENO) schemes for the MLB and HS models. Numerical examples illustrate that WENO schemes which use this spectral information are superior in resolution, and even in efficiency for the same overall resolution, to component-wise WENO schemes. 相似文献
915.
NNP‐Type Pincer Imidazolylphosphine Ruthenium Complexes: Efficient Base‐Free Hydrogenation of Aromatic and Aliphatic Nitriles under Mild Conditions
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Dr. Rosa Adam Dr. Elisabetta Alberico Dr. Wolfgang Baumann Dr. Hans‐Joachim Drexler Dr. Ralf Jackstell Dr. Henrik Junge Prof. Dr. Matthias Beller 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(14):4991-5002
A series of seven novel NImNHP‐type pincer imidazolylphosphine ruthenium complexes has been synthesized and fully characterized. The use of hydrogenation of benzonitrile as a benchmark test identified [RuHCl(CO)(NImNHPtBu)] as the most active catalyst. With its stable Ru?BH4 analogue, in which chloride is replaced by BH4, a broad range of (hetero)aromatic and aliphatic nitriles, including industrially interesting adiponitrile, has been hydrogenated under mild and base‐free conditions. 相似文献
916.
Heraclio López-Ruiz Horacio Briseño-OrtegaSusana Rojas-Lima Rosa SantillanNorberto Farfán 《Tetrahedron letters》2011,52(33):4308-4312
A novel, one-pot, phenylboronic acid catalyzed, cyanide promoted synthesis of 2-(2-hydroxyphenyl)benzoxazoles from salicylaldehydes and o-aminophenols is described. The synthesis is characterized by mild conditions, short reaction times, and simple workup of crystalline, high purity products. 相似文献
917.
This experimental investigation concerns the static and dynamic behaviour of a rigid balanced rotor on journal bearings. Running conditions were chosen in order to obtain relatively high eccentricity ratios near the instability threshold speeds.The results, compared also with the theoretical predictions of some authors, have substantially shown the importance of examining the static behaviour near the instability threshold speed to allow a correct interpretation of some aspects of the dynamic behaviour.In order to clarify the discrepancies between the observed and the theoretically predicted dynamic behaviour, some further tests have been carried out.
Sommario E' stato esaminato sperimentalmente sia il comportamento statico che quello dinamico di un rotore rigido e bilanciato sostenuto da cuscinetti cilindrici lubrificati.Le condizioni di funzionamento sono state scelte in modo tale che, in prossimità della soglia di instabilità, il valore del rapporto di eccentricità risultasse relativamente grande.I risultati, confrontati anche con le indicazioni teoriche di altri autori, hanno sostanzialmente evidenziato l'importanza dell'esame del comportamento statico in prossimità della soglia di instabilità al fine di interpretare correttamente alcuni aspetti del fenomeno dell'instabilità.Sono state inoltre effettuate una serie di ulteriori indagini con lo scopo di chiarire le discordanze fra il comportamento dinamico osservato e quello previsto dalla teoria.相似文献
918.
Yoshiaki Nishijima Yoshikazu Hashimoto Lorenzo Rosa Jacob B. Khurgin Saulius Juodkazis 《Applied Physics A: Materials Science & Processing》2014,117(2):647-650
We demonstrate the qualitative analysis of surface-enhanced Raman scattering (SERS) intensity and optical extinction by experimentally and numerically. This analytical methods are well matched not only the simple square lattice array of nanostructures, but also the rectangular lattices. We also demonstrate SERS selectivity of modes controlling the optical extinction of excitation and scattering wavelength. Both square lattice and rectangular lattice have similar tendency, but the rectangular lattice structures have much higher selectivity of SERS modes. 相似文献
919.
920.
Andrea R. da Silva Ricardo Q. Aucélio Rosa I. Rodríguez-Cotto Mario G. Ortiz-Martínez Evasomary Rivera-Ramírez Daniela Perroni Frias Mariangela Macchione Braulio Jiménez-Vélez Adriana Gioda 《Journal of nanoparticle research》2014,16(10):1-11
The synthesis procedure represents a key aspect in designing the physical and chemical properties of gold nanoparticles. The current study proposes a simple approach for gold nanoparticles synthesis using non-thermal plasma. The novelty of the setup consists in producing an in-liquid plasma discharge in argon bubbles that are externally generated in the solution exposed to treatment. Because plasma is the source of active species which are directly involved in gold reduction, no additional reducing agent was necessary. Collagen protein was used as capping agent. A plasma treatment of 10 min is sufficient for obtaining stable colloidal solutions with UV-Vis absorption maximum at 530 nm. Transmission electron microscopy images revealed preponderant spherical nanoparticles with dimensions in the range of 6–20 nm. The method of synthesis distinguishes by its good reproducibility, facility, efficiency, and ability to generate stable colloidal nanoparticles after several minutes of plasma exposure. 相似文献