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Marco Aldo Ortenzi Stefano Antenucci Stefania Marzorati Lucia Panzella Silvia Molino Jos ngel Rufin-Henares Alessandra Napolitano Luisella Verotta 《Molecules (Basel, Switzerland)》2021,26(2)
Among bioactive phytochemicals, ellagic acid (EA) is one of the most controversial because its high antioxidant and cancer-preventing effects are strongly inhibited by low gastrointestinal absorption and rapid excretion. Strategies toward an increase of solubility in water and bioavailability, while preserving its structural integrity and warranting its controlled release at the physiological targets, are therefore largely pursued. In this work, EA lysine salt at 1:4 molar ratio (EALYS), exhibiting a more than 400 times increase of water solubility with respect to literature reports, was incorporated at 10% in low methoxylated (LM) and high methoxylated (HM) pectin films. The release of EA in PBS at pH 7.4 from both film preparations was comparable and reached 15% of the loaded compound over 2 h. Under simulated gastric conditions, release of EA from HM and LM pectin films was minimal at gastric pH, whereas higher concentrations—up to 300 μM, corresponding to ca. 50% of the overall content—were obtained in the case of the HM pectin film after 2 h incubation at the slightly alkaline pH of small intestine environment, with the enzyme and bile salt components enhancing the release. EALYS pectin films showed a good prebiotic activity as evaluated by determination of short chain fatty acids (SCFAs) levels following microbial fermentation, with a low but significant increase of the effects produced by the pectins themselves. Overall, these results highlight pectin films loaded with EALYS salt as a promising formulation to improve administration and controlled release of the compound. 相似文献
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Bénito S Molino F Bruneau CH Colin T Gay C 《The European physical journal. E, Soft matter》2012,35(6):51-17
The occurrence of shear bands in a complex fluid is generally understood as resulting from a structural evolution of the material under shear, which leads (from a theoretical perspective) to a non-monotonic stationary flow curve related to the coexistence of different states of the material under shear. In this paper we present a scenario for shear-banding in a particular class of complex fluids, namely foams and concentrated emulsions, which differs from other scenarios in two important ways. First, the appearance of shear bands is shown to be possible both without any intrinsic physical evolution of the material (e.g. via a parameter coupled to the flow such as concentration or entanglements) and without any finite critical shear rate below which the flow does not remain stationary and homogeneous. Secondly, the appearance of shear bands depends on the initial conditions, i.e. the preparation of the material. In other words, it is history dependent. This behaviour relies on the tensorial character of the underlying model (2D or 3D) and is triggered by an initially inhomogeneous strain distribution in the material. The shear rate displays a discontinuity at the band boundary whose amplitude is history dependent and thus depends on the sample preparation. 相似文献
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Lucas A. Freeman Akachukwu D. Obi Haleigh R. Machost Andrew Molino Asa W. Nichols Diane A. Dickie David J. D. Wilson Charles W. Machan Robert J. Gilliard Jr 《Chemical science》2021,12(10):3544
The mono- and dianions of CO2 (i.e., CO2− and CO22−) have been studied for decades as both fundamentally important oxycarbanions (anions containing only C and O atoms) and as critical species in CO2 reduction and fixation chemistry. However, CO2 anions are highly unstable and difficult to study. As such, examples of stable compounds containing these ions are extremely limited; the unadulterated alkali salts of CO2 (i.e., MCO2, M2CO2, M = alkali metal) decompose rapidly above 15 K, for example. Herein we report the chemical reduction of a cyclic (alkyl)(amino) carbene (CAAC) adduct of CO2 at room temperature by alkali metals, which results in the formation of CAAC-stabilized alkali CO2− and CO22− clusters. One-electron reduction of CAAC–CO2 adduct (1) with lithium, sodium or potassium metal yields stable monoanionic radicals [M(CAAC–CO2)]n (M = Li, Na, K, 2–4) analogous to the alkali CO2− radical, and two-electron alkali metal reduction affords dianionic clusters of the general formula [M2(CAAC–CO2)]n (5–8) with reduced CO2 units which are structurally analogous to the carbonite anion CO22−. It is notable that crystalline clusters of these alkali–CO2 salts may also be isolated via the “one-pot” reaction of free CO2 with free CAAC followed by the addition of alkali metals – a process which does not occur in the absence of carbene. Each of the products 2–8 was investigated using a combination of experimental and theoretical methods.The direct chemical reduction of CAACCO2 adducts by alkali metals to yield multinuclear clusters is reported. The mono- and dianions of CO2 have been studied for decades and are fundamentally important oxycarbanions and critical species in CO2 fixation chemistry. 相似文献
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Let M be a connected oriented closed n-manifold. A riemannian flow
on M is an oriented one dimensional foliation which admits a bundle-like metric.We give a caracterization of isometric flows as riemannian flows whose basic cohomology H
b
n–1
(M,
) is non trivial in degree (n–1). A second caracterization involves the triviality of the central sheaf.We show also that
has a section if and only if H
b
n–1
(M,
) has a non trivial image in Hn–1(M). 相似文献
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Dr. Wenlong Yang Kelsie E. Krantz Dr. Diane A. Dickie Andrew Molino Prof. Dr. David J. D. Wilson Prof. Dr. Robert J. Gilliard Jr. 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(10):3999-4003
The synthesis and reactivity study of the first isolable boraphosphaketene, cyclic(alkyl)(amino) carbene (CAAC)-borafluorene-P=C=O ( 2 ), is described. Photolysis of compound 2 results in the formation of CAAC-stabilized BP-doped phenanthryne ( 3 ) through tandem decarbonylation, monoatomic phosphide insertion, and ring-expansion. Notably, while BN-doped phenanthryne was previously discussed as a reactive intermediate which could not be isolated, the heavier BP-doped analogue exhibits remarkable solution and solid-state stability. The reactivity of 2 with stable carbenes was also explored. Addition of CAAC to 2 led to migration of the original CAAC ligand from boron to phosphorus and coordination of the added CAAC to carbon, affording compound 4 . Reaction of 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene (NHC) with 2 resulted in N−C bond activation to give the unusual spiro-heterocyclic compound ( 5 ). 相似文献
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Wenlong Yang Kelsie E. Krantz Lucas A. Freeman Diane A. Dickie Andrew Molino Gernot Frenking Sudip Pan David J. D. Wilson Robert J. Gilliard 《Angewandte Chemie (International ed. in English)》2020,59(10):3850-3854
N‐Heterocyclic carbene (NHC)‐ and cyclic (alkyl)(amino)carbene (CAAC)‐stabilized borafluorene radicals have been isolated and characterized by elemental analysis, single‐crystal X‐ray diffraction, UV/Vis absorption, cyclic voltammetry (CV), electron paramagnetic resonance (EPR) spectroscopy, and theoretical studies. Both the CAAC–borafluorene radical ( 2 ) and the NHC–borafluorene radical ( 4 ) have a considerable amount of spin density localized on the boron atoms (0.322 for 2 and 0.369 for 4 ). In compound 2 , the unpaired electron is also partly delocalized over the CAAC ligand carbeneC and N atoms. However, the unpaired electron in compound 4 mainly resides throughout the borafluorene π‐system, with significantly less delocalization over the NHC ligand. These results highlight the Lewis base dependent electrostructural tuning of materials‐relevant radicals. Notably, this is the first report of crystalline borafluorene radicals, and these species exhibit remarkable solid‐state and solution stability. 相似文献
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Christopher J. Smedley Qinheng Zheng Bing Gao Suhua Li Andrew Molino Hendrika M. Duivenvoorden Belinda S. Parker David J. D. Wilson K. Barry Sharpless John E. Moses 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(14):4600-4604
SuFEx is a new‐generation click chemistry transformation that exploits the unique properties of S?F bonds and their ability to undergo near‐perfect reactions with nucleophiles. We report here the first SuFEx‐based procedure for the efficient synthesis of pharmaceutically important triflones and bis(trifluoromethyl)sulfur oxyimines from sulfonyl fluorides and iminosulfur oxydifluorides, respectively. The new process involves rapid S?F exchange with trifluoromethyltrimethylsilane (TMSCF3) upon activation by potassium bifluoride in anhydrous DMSO. The reaction tolerates a wide selection of substrates and proceeds under mild conditions without need for chromatographic purification. A tentative mechanism is proposed involving nucleophilic displacement of S?F by the trifluoromethyl anion via a five‐coordinate intermediate. The utility of late‐stage SuFEx trifluoromethylation is demonstrated through the synthesis and selective anticancer properties of a bis(trifluoromethyl)sulfur oxyimine. 相似文献
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Using dynamic light scattering in heterodyne mode, we measure velocity profiles in a much studied system of wormlike micelles (CPCl/NaSal) known to exhibit both shear-banding and stress plateau behavior. Our data provide evidence for the simplest shear-banding scenario, according to which the effective viscosity drop in the system is due to the nucleation and growth of a highly sheared band in the gap, whose thickness linearly increases with the imposed shear rate. We discuss various details of the velocity profiles in all the regions of the flow curve and emphasize the complex, non-Newtonian nature of the flow in the highly sheared band. 相似文献