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771.
Carbohydrate-based novel bis(ammonium) chiral ionic liquids have been synthesized by following a straightforward protocol using isomannide as the substrate. Their applications in chiral discrimination and optical resolution of racemates have been established. 相似文献
772.
During the past 10 years multifractal analysis has received an enormous interest. For a sequence n(φn) of functions φn:X→M on a metric space X, multifractal analysis refers to the study of the Hausdorff dimension of the level sets
773.
Shibata S Zhang Z Korotkov KV Delarosa J Napuli A Kelley AM Mueller N Ross J Zucker FH Buckner FS Merritt EA Verlinde CL Van Voorhis WC Hol WG Fan E 《Analytical and bioanalytical chemistry》2011,401(5):1585-1591
Ultrafiltration provides a generic method to discover ligands for protein drug targets with millimolar to micromolar K(d), the typical range of fragment-based drug discovery. This method was tailored to a 96-well format, and cocktails of fragment-sized molecules, with molecular masses between 150 and 300 Da, were screened against medical structural genomics target proteins. The validity of the method was confirmed through competitive binding assays in the presence of ligands known to bind the target proteins. 相似文献
774.
Vortex behavior and characteristics in a confined rectangular jet with a co-flow were examined using vortex swirling strength
as a defining characteristic. On the left side of the jet, the positively (counterclockwise) rotating vortices are dominant,
while negatively rotating vortices are dominant on the right side of the jet. The characteristics of vortices, such as population
density, average size and strength, and deviation velocity, were calculated and analyzed in both the cross-stream direction
and the streamwise direction. In the near-field of the jet, the population density, average size and strength of the dominant
direction vortices show high values on both sides of the center stream with a small number of counter-rotating vortices produced
in the small wake regions close to jet outlet. As the flow develops, the wake regions disappear, these count-rotating vortices
also disappear, and the population of the dominant direction vortices increase and spread in the jet. The mean size and strength
of the vortices decrease monotonically with streamwise coordinate. The signs of vortex deviation velocity indicate the vortices
transfer low momentum to high-velocity region and high momentum to the low velocity region. The developing trends of these
characteristics were also identified by tracing vortices using time-resolved particle image velocimetry data. Both the mean
tracked vortex strength and size decrease with increasing downstream distance overall. At the locations of the left peak of
turbulent kinetic energy, the two-point spatial cross-correlation of swirling strength with velocity fluctuation and concentration
fluctuation were calculated. All the correlation fields contain one positively correlated region and one negatively correlated
region although the orientations of the correlation fields varied, due to the flow transitioning from wake, to jet, to channel
flow. Finally, linear stochastic estimation was used to calculate conditional structures. The large-scale structures in the
velocity field revealed by linear stochastic estimation are spindle-shaped with a titling stream-wise major axis. 相似文献
775.
Stine T. Olsen Thorsten Hansen Kurt V. Mikkelsen 《Theoretical chemistry accounts》2011,130(4-6):839-850
We present theoretical methods and computational strategies of the effects of nanoparticles on linear optical properties of molecules. We present quantum mechanical-molecular mechanics response methods for calculating electromagnetic properties of molecules interacting with nanoparticles and we report strategies for calculating electronic and redox states of molecules sandwiched between gold nanoparticles. 相似文献
776.
777.
778.
Singh SK Sharma VK Bohra K Olsen CE Prasad AK 《The Journal of organic chemistry》2011,76(18):7556-7562
A Novozyme-435 catalytic methodology has been developed for selective deacylation of one of the acyloxy functions involving a primary -OH group over the other acyloxy functions involving primary and secondary -OH groups in 4'-C-acyloxymethyl-2',3',5'-tri-O-acyl-β-D-xylofuranosyl nucleosides. Optimization of the biocatalytic reaction revealed that tetra-O-butanoyl-β-D-xylofuranosyl nucleosides are the best substrates for the enzyme. The possibility of acyl migration during enzymatic deacylation reactions has been ruled out by carrying out biocatalytic deacylation reactions on mixed esters of 4'-C-hydroxymethyl-2',3',5'-tri-O-acetyl-β-D-xylofuranosyl nucleosides. The developed methodology has been used for the efficient synthesis of xylo-LNA monomers T, U, A, and C in good yields. 相似文献
779.
Akine S Hotate S Matsumoto T Nabeshima T 《Chemical communications (Cambridge, England)》2011,47(10):2925-2927
The left-handed isomer of the helical complex [LZn(3)La(OAc)(3)] was spontaneously enriched from 50 : 50 to 87 : 13 when the quasiracemate crystals were dissolved. The invertible helicity of [LZn(3)La(OAc)(3)] (global chirality) helps the quasiracemate formation and the fixed point chirality of the R,R-cyclohexanediamine moiety (local chirality) effectively controls the global chirality in solution. 相似文献
780.
We look at the time–frequency localization of generators of lattice Gabor systems. For a generator of a Riesz basis, this
localization is described by the classical Balian–Low theorem. We establish Balian–Low type theorems for complete and minimal
Gabor systems with a frame-type approximation property. These results describe how the best possible localization of a generator
is limited by the degree of control over the coefficients in approximations given by the system, and provide a continuous
transition between the classical Balian–Low conditions and the corresponding conditions for generators of complete and minimal
systems. Moreover, this holds for the non-symmetric generalizations of these theorems as well. 相似文献