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51.
52.
Dr. Ross J. Ellis Dr. Jy Chartres Dr. David K. Henderson Dr. Rafel Cabot Dr. Patricia R. Richardson Dr. Fraser J. White Prof. Martin Schröder Jennifer R. Turkington Prof. Peter A. Tasker Dr. Kathryn C. Sole 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(25):7715-7728
Four new sterically hindered pyridines, L1–L4‐containing amido substituents at the 2‐position act as efficient solvent extractants for [CoCl4]2? or [ZnCl4]2? from acidic chloride solutions through protonation of the pyridino N‐centre to form the neutral outer‐sphere complexes [(LH)2MCl4]. These ionophores show very high selectivity for chlorometallate anions over chloride ion and are readily stripped to liberate the free‐metal chlorides without the formation of inner‐sphere complexes [ML2Cl2]. Single‐crystal X‐ray structure determinations of [(L2H)2CoCl4] and [(L2H)2ZnCl4] (L2=2‐(4,6‐di‐tert‐butylpyridin‐2‐yl)‐N,N′‐dihexylmalonamide) coupled with 1H NMR spectroscopy and DFT calculations on L2H+ and other complexes of [ZnCl4]2? confirm that the pyridinium NH group does not address the outer co‐ordination sphere of the metallanion, but rather forms a hydrogen bond to the pendant amide groups and thus pre‐organizes the ligand to present both C? H and amido N? H hydrogen‐bond donors to the [MCl4]2? ions. The selectivity for chlorometallates over chloride ions shown by this class of extractants arises from their ability to present several polarized C? H units towards the charge‐diffuse ions [MCl4]2?, whereas the smaller, “harder” chloride anion prefers to be associated with the amido N? H hydrogen‐bond donors. 相似文献
53.
It is well known that the validity of the so called Lenard–Magri scheme of integrability of a bi-Hamiltonian PDE can be established if one has some precise information on the corresponding 1st variational Poisson cohomology for one of the two Hamiltonian operators. In the first part of the paper we explain how to introduce various cohomology complexes, including Lie superalgebra and Poisson cohomology complexes, and basic and reduced Lie conformal algebra and Poisson vertex algebra cohomology complexes, by making use of the corresponding universal Lie superalgebra or Lie conformal superalgebra. The most relevant are certain subcomplexes of the basic and reduced Poisson vertex algebra cohomology complexes, which we identify (non-canonically) with the generalized de Rham complex and the generalized variational complex. In the second part of the paper we compute the cohomology of the generalized de Rham complex, and, via a detailed study of the long exact sequence, we compute the cohomology of the generalized variational complex for any quasiconstant coefficient Hamiltonian operator with invertible leading coefficient. For the latter we use some differential linear algebra developed in the Appendix. 相似文献
54.
P. Monachesi R. Capelli R. Del Sole 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,26(2):159-166
We calculate the optical functions of Pd using the ab initio, all-electron Full Potential Linear Muffin Tin Orbital method within the framework of the Density Functional Theory in the
Local Density approximation. We test, in the case of Pd, the convergence of the dielectric function and energy loss function
in different energy ranges vs. the completeness of the basis and give a quantitative estimate of the accuracy. The present approach opens the possibility
of extending the energy range where the optical functions can be calculated with good accuracy without increasing the computational
effort.
Received 4 September 2001 相似文献
55.
56.
Alberto De Sole Victor G. Kac Daniele Valeri 《Communications in Mathematical Physics》2013,323(2):663-711
We describe of the generalized Drinfeld-Sokolov Hamiltonian reduction for the construction of classical ${\mathcal{W}}$ W -algebras within the framework of Poisson vertex algebras. In this context, the gauge group action on the phase space is translated in terms of (the exponential of) a Lie conformal algebra action on the space of functions. Following the ideas of Drinfeld and Sokolov, we then establish under certain sufficient conditions the applicability of the Lenard-Magri scheme of integrability and the existence of the corresponding integrable hierarchy of bi-Hamiltonian equations. 相似文献
57.
R. Touzani S. El Kadiri A. Zerrouki G. Vasapollo S. Scorrano R. Del Sole M. G. Manera R. Rella 《Research on Chemical Intermediates》2012,38(9):2245-2254
Synthesis of a series of heterocyclic compounds based on pyrazole units is reported. The possibility of using these compounds, as solid-state thin layers deposited on quartz substrates, for optical recognition of hazardous pollutant gases was investigated. The gases SO2, NO2, CO, CH4, and NH3 were studied. Two of the ligand layers had reversible sensitivity toward SO2, with good reaction time. The presence of CO, CH4 NO2, and NH3 had no effect on the optical properties. Morphological characterization by use of AFM microscopy was also investigated. 相似文献
58.
Beverly S Colley Melissa A Cavallin KC Biju David R Marks Debra A Fadool 《BMC neuroscience》2009,10(1):1-19
Background
Developmental dyslexia is a specific cognitive disorder in reading acquisition that has genetic and neurological origins. Despite histological evidence for brain differences in dyslexia, we recently demonstrated that in large cohort of subjects, no differences between control and dyslexic readers can be found at the macroscopic level (MRI voxel), because of large variances in brain local volumes. In the present study, we aimed at finding brain areas that most discriminate dyslexic from control normal readers despite the large variance across subjects. After segmenting brain grey matter, normalizing brain size and shape and modulating the voxels' content, normal readers' brains were used to build a 'typical' brain via bootstrapped confidence intervals. Each dyslexic reader's brain was then classified independently at each voxel as being within or outside the normal range. We used this simple strategy to build a brain map showing regional percentages of differences between groups. The significance of this map was then assessed using a randomization technique.Results
The right cerebellar declive and the right lentiform nucleus were the two areas that significantly differed the most between groups with 100% of the dyslexic subjects (N = 38) falling outside of the control group (N = 39) 95% confidence interval boundaries. The clinical relevance of this result was assessed by inquiring cognitive brain-based differences among dyslexic brain subgroups in comparison to normal readers' performances. The strongest difference between dyslexic subgroups was observed between subjects with lower cerebellar declive (LCD) grey matter volumes than controls and subjects with higher cerebellar declive (HCD) grey matter volumes than controls. Dyslexic subjects with LCD volumes performed worse than subjects with HCD volumes in phonologically and lexicon related tasks. Furthermore, cerebellar and lentiform grey matter volumes interacted in dyslexic subjects, so that lower and higher lentiform grey matter volumes compared to controls differently modulated the phonological and lexical performances. Best performances (observed in controls) corresponded to an optimal value of grey matter and they dropped for higher or lower volumes.Conclusion
These results provide evidence for the existence of various subtypes of dyslexia characterized by different brain phenotypes. In addition, behavioural analyses suggest that these brain phenotypes relate to different deficits of automatization of language-based processes such as grapheme/phoneme correspondence and/or rapid access to lexicon entries. 相似文献59.
Ibrahim S. Alkhaibari Hansa Raj KC Subrata Roy Mohd. K. Abu-gazleh David F. Gilmore Mohammad A. Alam 《Molecules (Basel, Switzerland)》2021,26(16)
Enterococci and methicillin-resistant S. aureus (MRSA) are among the menacing bacterial pathogens. Novel antibiotics are urgently needed to tackle these antibiotic-resistant bacterial infections. This article reports the design, synthesis, and antimicrobial studies of 30 novel pyrazole derivatives. Most of the synthesized compounds are potent growth inhibitors of planktonic Gram-positive bacteria with minimum inhibitory concertation (MIC) values as low as 0.25 µg/mL. Further studies led to the discovery of several lead compounds, which are bactericidal and potent against MRSA persisters. Compounds 11, 28, and 29 are potent against S. aureus biofilms with minimum biofilm eradication concentration (MBEC) values as low as 1 µg/mL. 相似文献
60.
We present ab initio calculations of the excited state properties of liquid water in the framework of many-body Green's function formalism. Snapshots taken from molecular dynamics simulations are used as input geometries to calculate electronic and optical spectra, and the results are averaged over the different configurations. The optical absorption spectra with the inclusion of excitonic effects are calculated by solving the Bethe-Salpeter equation. The insensitivity of screening effects to a particular configuration make these calculations feasible. The resulting spectra, which are strongly modified by many-body effects, are in good agreement with experiments. 相似文献