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81.
Manuel Alberto Flores‐Hidalgo Daniel Glossman‐Mitnik D. H. Galvan Diana Barraza‐Jimenez 《中国化学会会志》2013,60(8):1082-1091
Density Functional Theory employing hybrid and M06 functionals in combination with three different basis sets is used to calculate the ground state of a cage like (ZnO)12 nanocluster which has been consistently reported as the more stable cluster for its particular size. B3LYP and B3PW91 hybrid functionals combined with 6‐31+G*, Lanl2dz and SDD basis sets are employed to treat the ZnO molecular system. Alternatively, three M06 functionals in combination with three basis sets are employed in the nanostructure calculations. Results obtained by treating ZnO sodalite cage nanocluster with M06 functionals demonstrated comparable quality to results obtained with hybrid functionals. Within this study, efficient theoretical DFT methods with the widely known hybrid and the recently created M06 meta‐hybrid functionals are employed to study nanostructured ZnO. Our resulting parameters provide a fresh approach performance wise on the different theoretical methods to treat transition metal nanostructures, particularly, ZnO nanoclusters geometry and electronic structure. 相似文献
82.
We improve the range of exponents for the restriction problem for the 3-d paraboloid over finite fields. The key new ingredient is a variant of the Bourgain–Katz–Tao finite field incidence theorem derived from sum-product estimates. In prime order fields, we give an explicit relationship between the exponent in this incidence theorem and restriction estimates for the paraboloid. 相似文献
83.
84.
《Tetrahedron letters》2014,55(4):877-879
Broussonetone A (1) and broussonetone B (2), two novel dimeric abietane diterpenes, have been isolated from Salvia broussonetii root cultures transformed by Agrobacterium rhizogenes. The structure of broussonetone A was determined from spectroscopic data and confirmed by X-ray analysis. This dimer can be formed by a [4+2]-cycloaddition of two molecules of 13β-hydroxyabieta-8(14),9(11)-dien-12-one. NMR data of broussonetone B indicated that the C-20 methyl in part B of the broussonetone A molecule had been substituted by an aldehyde group. Thus, broussonetone B could be formed by an analogous Diels Alder reaction between 13β-hydroxyabieta-8(14),9(11)-dien-12-one as the dienophile and its 20-oxo derivative as the electrophile. 相似文献
85.
For the first time the possibility of voltammetry used for the determination of aflatoxin B1 on a glassy carbon electrode was shown. The effect of pH of a supporting electrolyte on the analytical signal of aflatoxin B1 has been investigated and it was shown that there is a more pronounced peak with a maximum current at pH of 5.33. The most favorable supporting electrolyte for a linear range of detectable concentrations of aflatoxin B1 – 0.1 M (NH4)2SO4 was determined. The results of research on the development of conditions of voltammetric measurement of aflatoxin B1 are presented. 相似文献
86.
《Journal of Saudi Chemical Society》2021,25(10):101324
Bioassay guided fractionation of Pistacia integerrima crude methanolic extract gave Pistacide-A (1) and Pistacide-B (2), along with ten known phytochemicals (3–12). Biochemical analysis of crude plant extract, in-vitro and in-silico carbonic anhydrase inhibitory potential of newly isolated compounds Pistacide-A (1) and Pistacide-B (2) were performed. The cytotoxicity of extract in methanol, ethylacetate and n-butanol against Artemia salina brine-shrimp was 34.98 g/ml, 160.81 g/ml, and 135.77 g/ml, respectively. The significant antimicrobial activity was exhibited by crude, ethyl acetate, and n-butanol fractions. Compounds 1 (IC50 = 6.51 ± 0.42 mM) and 2 (IC50 = 2.85 ± 0.09 mM) showed good carbonic anhydrase inhibition compared with standard zonisamide drug (IC50 = 1.87 ± 0.003 mM). In addition, we have also clarified the electronic properties, absorption wavelengths, molecular electrostatic potential and Hirshfeld analysis by first-principles studies. The coherent intra-molecular charge transfer was seen from occupied to unoccupied molecular orbitals. The absorption wavelengths calculated at time dependent B3LYP/6-31G** level in methanol provided excellent accord with the experimental evidence. Molecular docking score revealed that Pistacide-B would be an efficient drug than its other counterpart that is rational to the experimental data. 相似文献
87.
Dijana Jeli 《Molecules (Basel, Switzerland)》2021,26(1)
Amorphous solid dispersion drug delivery systems (ASD DDS) were proved to be efficient for the enhancement of solubility and bioavailability of poorly water-soluble drugs. One of the major keys for successful preparation of ASD is the selection of appropriate excipients, mostly polymers, which have a crucial role in improving drug solubility and its physical stability. Even though, excipients should be chemically inert, there is some evidence that polymers can affect the thermal stability of active pharmaceutical ingredients (API). The thermal stability of a drug is closely related to the shelf-life of pharmaceutical products and therefore it is a matter of high pharmaceutical relevance. An overview of thermal stability of amorphous solids is provided in this paper. Evaluation of thermal stability of amorphous solid dispersion is perceived from the physicochemical perspective, from a kinetic (motions) and thermodynamic (energy) point of view, focusing on activation energy and fragility, as well all other relevant parameters for ASD design, with a glance on computational kinetic analysis of solid-state decomposition. 相似文献
88.
Mathilde Montibus Xavier Vitrac Vronique Coma Anne Loron Laetitia Pinson-Gadais Nathalie Ferrer Marie-Noëlle Verdal-Bonnin Julien Gabaston Pierre Waffo-Tguo Florence Richard-Forget Vessela Atanasova 《Molecules (Basel, Switzerland)》2021,26(2)
Fusarium graminearum is a fungal pathogen that can colonize small-grain cereals and maize and secrete type B trichothecene (TCTB) mycotoxins. The development of environmental-friendly strategies guaranteeing the safety of food and feed is a key challenge facing agriculture today. One of these strategies lies on the promising capacity of products issued from natural sources to counteract crop pests. In this work, the in vitro efficiency of sixteen extracts obtained from eight natural sources using subcritical water extraction at two temperatures was assessed against fungal growth and TCTB production by F. graminearum. Maritime pine sawdust extract was shown to be extremely efficient, leading to a significant inhibition of up to 89% of the fungal growth and up to 65% reduction of the mycotoxin production by F. graminearum. Liquid chromatography/mass spectrometry analysis of this active extract revealed the presence of three families of phenolics with a predominance of methylated compounds and suggested that the abundance of methylated structures, and therefore of hydrophobic compounds, could be a primary factor underpinning the activity of the maritime pine sawdust extract. Altogether, our data support that wood/forest by-products could be promising sources of bioactive compounds for controlling F. graminearum and its production of mycotoxins. 相似文献
89.
We exhibit a Poisson module restoring a twisted Poincaré duality between Poisson homology and cohomology for the polynomial
algebra endowed with Poisson bracket arising from a uniparametrised quantum affine space. This Poisson module is obtained as the
semiclassical limit of the dualising bimodule for Hochschild homology of the corresponding quantum affine space. As a corollary
we compute the Poisson cohomology of R, and so retrieve a result obtained by direct methods (so completely different from ours) by Monnier.
This research of the first author was supported by a Marie Curie Intra-European Fellowship within the 6th European Community
Framework Programme. The second author was supported by EPSRC Grant EP/D034167/1. 相似文献
90.
Scaling symmetry of -type Drinfel’d–Sokolov hierarchy is investigated. Applying similarity reduction to the hierarchy, one can obtain the Schlesinger
equation with (n + 1) regular singularities. Especially in the case of n = 3, the hierarchy contains the three-wave resonant system and the similarity reduction gives the generic case of the Painlevé
VI equation. We also discuss Weyl group symmetry of the hierarchy.
相似文献