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61.
Dr. Timothy A. Barendt Dr. Melissa L. Ball Dr. Qizhi Xu Dr. Boyuan Zhang Dr. Brandon Fowler Ayden Schattman Virginia Cary Ritter Prof. Michael L. Steigerwald Prof. Colin Nuckolls 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(17):3744-3748
This work presents a synergy between organic electronics and supramolecular chemistry, in which a host–guest complex is designed to function as an efficacious electronic material. Specifically, the noncovalent recognition of a fullerene, phenyl-C61-butyric acid methyl ester ( PC61BM ), by an alternating perylene diimide ( P )-bithiophene ( B ) conjugated macrocycle ( PBPB ) results in a greater than five-fold enhancement in electron mobility, relative to the macrocycle alone. Characterization and quantification of the binding of fullerenes by host PBPB is provided alongside evidence for intermolecular electronic communication within the host–guest complexes. 相似文献
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Kirralee J. Burke Dr. Liam J. Stephens Dr. Melissa V. Werrett Prof. Philip C. Andrews 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(34):7657-7671
A series of homoleptic and heteroleptic bismuth(III) flavonolate complexes derived from six flavonols of varying substitution have been synthesised and structurally characterised. The complexes were evaluated for antibacterial activity towards several problematic Gram-positive (Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant Enterococcus (VRE)) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacteria. The cell viability of COS-7 (monkey kidney) cells treated with the bismuth flavonolates was also studied to determine the effect of the complexes on mammalian cells. The heteroleptic complexes [BiPh(L)2] (in which L=flavonolate) showed good antibacterial activity towards all of the bacteria but reduced COS-7 cell viability in a concentration-dependent manner. The homoleptic complexes [Bi(L)3] exhibited activity towards the Gram-positive bacteria and showed low toxicity towards the mammalian cell line. Bismuth uptake studies in VRE and COS-7 cells treated with the bismuth flavonolate complexes indicated that Bi accumulation is influenced by both the substitution of the flavonolate ligands and the degree of substitution at the bismuth centre. 相似文献
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In this paper, we prove some spectral properties of the drifted Laplacian of self-shrinkers properly immersed in gradient shrinking Ricci solitons. Then we use these results to prove some geometric properties of self-shrinkers. For example, we describe a collection of domains in the ambient space that cannot contain self-shrinkers. 相似文献
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Simone Carradori Melissa D’Ascenzio Paola Chimenti Daniela Secci Adriana Bolasco 《Molecular diversity》2014,18(1):219-243
Monoamine oxidases (MAOs) are mitochondrial bound enzymes, which catalyze the oxidative deamination of monoamine neurotransmitters. Inside the brain, MAOs are present in two isoforms: MAO-A and MAO-B. The activity of MAO-B is generally higher in patients affected by neurodegenerative diseases like Alzheimer’s and Parkinson’s. Therefore, the search for potent and selective MAO-B inhibitors is still a challenge for medicinal chemists. Nature has always been a source of inspiration for the discovery of new lead compounds. Moreover, natural medicine is a major component in all traditional medicine systems. In this review, we present the latest discoveries in the search for selective MAO-B inhibitors from natural sources. For clarity, compounds have been classified on the basis of structural analogy or source: flavonoids, xanthones, tannins, proanthocyanidins, iridoid glucosides, curcumin, alkaloids, cannabinoids, and natural sources extracts. MAO inhibition values reported in the text are not always consistent due to the high variability of MAO sources (bovine, pig, rat brain or liver, and human) and to the heterogeneity of the experimental protocols used. 相似文献
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Gregory B. Kharas Sonia E. Chavez Harrison S. Browning Jennifer A. Sepe Mario E. Romanelli Melissa K. Susnis 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(10):751-755
Electrophilic trisubstituted ethylenes, ring-disubstituted methyl 2-cyano-3-phenyl-2-propenoates, RPhCH?C(CN)CO2CH3, where R is 2,5-dichloro, 3,5-dichloro, 2,3-difluoro, 3-chloro-2-fluoro, 3-chloro-4-fluoro, 4-chloro-3-fluoro, 2-chloro-5-nitro, and 2-chloro-6-nitro were prepared and copolymerized with styrene. The monomers were synthesized by the piperidine catalyzed Knoevenagel condensation of ring-disubstituted benzaldehydes and methyl cyanoacetate, and characterized by CHN analysis, IR, 1H and 13C-NMR. All the ethylenes were copolymerized with styrene (M1) in solution with radical initiation (ABCN) at 70°C. The compositions of the copolymers were calculated from nitrogen analysis and the structures were analyzed by IR, 1H and 13C-NMR. The order of relative reactivity (1/r1) for the monomers is 4-Cl-3-F (4.87) > 2,3-F2 (4.49) > 3-Cl-4-F (3.50) > 3-Cl-2-F (2.96) > 2-Cl-5-NO2 (2.02) > 2,5-Cl2 (1.54) > 2-Cl-6-NO2 (1.00) > 3,5-Cl2 (0.41). Relatively high Tg of the copolymers in comparison with that of polystyrene indicates a decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 200–500ºC range with residue (1.5–34.5% wt), which then decomposed in the 500-800ºC range. 相似文献
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Brenno Santos Leite Melissa Tatiana Andreuccetti Sibele Augusta Ferreira Leite José Vicente Hallak d’Angelo 《Journal of Thermal Analysis and Calorimetry》2013,112(3):1539-1544
As a consequence of the continuous increase in the production rate of pulp and paper mills around the world, a great quantity of black liquor, a by-product of the wood digestion process, is produced. This by-product has a great potential as biomass, but needs to be concentrated to higher solids content to be burned as fuel in a recovery boiler. This is necessary to make the pulping process economically feasible, incinerating black liquor to produce high pressure steam, recycling inorganic chemicals to the process. The greater the solids content in black liquor, the better the combustion process in the boiler. Nevertheless, concentration of solids in black liquor above 75 mass/%, causes scaling formation on the heat transfer surfaces of evaporators and concentrators, due to the precipitation of sodium salts, reducing the overall efficiency of this equipment. The aim of this work is to evaluate the use of thermal analyses techniques, TG and DSC, as alternative methods to estimate solids content in eucalyptus black liquor samples since this information is essential to understand scaling formation process, allowing actions to reduce this industrial problem. Traditional techniques applied to determine solids content use gravimetric methods, which are simple, fine, but take a lot of time to be executed. Thermal analyses have proved to be very accurate and have the advantage to be faster than the traditional techniques. On the other hand, the cost-benefit relationship of the traditional technique is much greater and the final decision which one should be used depends on the conditions available. 相似文献