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991.
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993.
Jesús Mosquera Dr. Salvatore Zarra Dr. Jonathan R. Nitschke 《Angewandte Chemie (International ed. in English)》2014,53(6):1556-1559
To prepare new functional covalent architectures that are difficult to synthesize using conventional organic methods, we developed a strategy that employs metal–organic assemblies as precursors, which are then reduced and demetalated. The host–guest chemistry of the larger receptor thus prepared was studied using NMR spectroscopy and fluorescence experiments. This host was observed to strongly bind aromatic polyanions in water, including the fluorescent dye molecule pyranine with nanomolar affinity, thus allowing for the design of an indicator‐displacement assay. 相似文献
994.
Evaluation of the surface affinity of water in three biochars using fast field cycling NMR relaxometry
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Salvatore Bubici Jean‐Pierre Korb Jiří Kučerik Pellegrino Conte 《Magnetic resonance in chemistry : MRC》2016,54(5):365-370
Many soil functions depend on the interaction of water with soil. The affinity of water for soils can be altered by applying soil amendments like stone meal, manure, or biochar (a carbonaceous material obtained by pyrolysis of biomasses). In fact, the addition of hydrophobic biochar to soil may increase soil repellency, reduce water‐adsorbing capacity, inhibit microbial activity, alter soil filter, buffer, storage, and transformation functions. For this reason, it is of paramount importance to monitor water affinity for biochar surface (also referred to as ‘wettability’) in order to better address its applications in soil systems. In this study, we propose the use of fast field cycling NMR relaxometry technique with the application of a new mathematical model for data interpretation, as a valid alternative to the traditional contact angle (CA) measurements for biochar wettability evaluation. Either NMR or CA results revealed the same wettability trend for the biochars studied here. The advantage of NMR relaxometry over CA measurements lies in the possibility to obtain at the microscopic level a variety of different information in only one shot. In fact, while CA provides only wettability evaluation, NMR relaxometry also allows achievement of the mechanisms for water molecular dynamics on biochar surface, thereby leading to the possibility to understand better, in future research, the role of biochar in increasing soil quality and plant nutrition. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
995.
Svetoslava Vankova Daniele Versaci Julia Amici Anna Ferrari Rosanna Rizzi Angela Altomare Salvatore Guastella Carlotta Francia Silvia Bodoardo Nerino Penazzi 《Journal of Solid State Electrochemistry》2017,21(12):3381-3388
Silicate materials have been proposed as alternative cathodes for Li-ion battery applications. A novel mixture of silicates, labelled Li6MnSi5, based on the molar ratio among the Li/Mn/Si precursors, with promising electrochemical properties as positive electrode material is synthesized through a solid-state reaction. The results indicate the proposed synthetic method as effective for preparation of nanostructured silicate powders with average particle diameter of 30 nm. Structural morphology of the samples was determined using X-ray powder diffraction (XRPD), XPS and FESEM analysis. A joint analysis by XRPD data and by density functional theory (DFT) identified LiHMn4Si5O15, Li2Mn4Si5O15, Li2Si2O5 and Li0.125Mn0.875SiO4 as components of Li6MnSi5 mixture. The electrochemical performance of Li6MnSi5 was evaluated by charge/discharge testing at constant current mode. Li6MnSi5 discharge behaviour is characterized by high capacity value of 480 mA h g?1, although such capacity fades gradually on cycling. Ex situ XPS studies carried out on the electrode in both full charged and discharged states pointed out that Li2Si2O5 is decisive for achieving such high capacity. The discharge/charge plateau is most probably related to the change in the oxidation state of silicon at the surface of the silica material. 相似文献
996.
Salvatore Nesci Vittoria Ventrella Fabiana Trombetti Maurizio Pirini Alessandra Pagliarani 《应用有机金属化学》2012,26(11):593-599
In mussel digestive gland mitochondria the environmental pollutant tri‐n‐butyltin (TBT), other than strongly inhibiting ATPase activity at <1.0 μ m , at ≥1.0 μ m concentration was previously found to desensitize F1FO‐ATPase to the antibiotic oligomycin. While F1FO‐ATPase inhibition is widely known as one of the main mitochondrial damages caused by TBT, the enzyme's desensitization to oligomycin was quite unexpected. The possible mechanisms involved are here stepwise approached, aiming at enlightening the molecular mechanism(s) of TBT toxicity and the still poorly investigated oligomycin interaction with FO. The findings strongly suggest that the oligomycin desensitization directly stems from the covalent binding of TBT to monothiols of the F1FO‐ATPase. This binding implies sulfur oxidation, irrespective of the possible formation of radical species in mitochondria, a mechanism which does not seem to be involved here. It is hypothesized that TBT interacts with the enzyme complex in at least two sites distinguished by different affinities: TBT binding to the high‐affinity site would lead to ATPase inhibition, while TBT binding to monothiols in the low‐affinity site could mirror the decrease in F1FO‐ATPase oligomycin sensitivity at ≥1.0 μ m TBT. Experiments carried out on inside‐out submitochondrial particles hint that TBT binding destabilizes the oligomycin‐blocked FO conformation, allowing proton flux recovery within FO, without uncoupling the catalytic function from proton channeling. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
997.
Ugo Andreaus Paolo Baragatti Maurizio De Angelis Salvatore Perno 《Nonlinear dynamics》2017,90(4):2387-2421
During strong earthquakes, structural pounding may occur between the equipment and the surrounding moat wall because of the limited separation distance and the deformations of the isolator. A potential mitigation measure for this problem is the incorporation of collision bumpers. The aim of the paper is to study the experimental dynamic response and to formulate numerical model of a base-isolated SDOF oscillator excited by a harmonic base acceleration and symmetrically bounded by two unilateral deformable and dissipative constraints. Static tests have been first performed to determine the static characteristics and the support conditions of the bumpers, and successively, shaking table tests have been carried out to investigate two different configurations: the absence and the presence of bumpers. In both configurations, tests were carried out with the same type of excitation to the base. Different values of the table acceleration peak were applied, different amplitude values of the total gap between mass and bumpers were considered, and also two different types of bumpers were employed. The experimental dynamic responses in the absence and in the presence of bumpers have been compared, and the results obtained in the presence of bumpers have also been used to identify some characteristics of the dynamics with impact (force and time of contact between mass and bumpers, energy dissipated by the bumpers during the impact, and coefficient of restitution). A suitable model has been developed to numerically simulate the behavior of the system by using a general-purpose computer code, achieving a good agreement with the experimental results. 相似文献
998.
999.
Matrix‐assisted laser desorption/ionization time‐of‐flight vs. fast‐atom bombardment and electrospray ionization mass spectrometry in the structural characterization of bacterial poly(3‐hydroxyalkanoates)
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1000.
The Ramanujan Journal - An upper quasi-density on $$\mathbf{{H}}$$ (the integers or the non-negative integers) is a real-valued subadditive function $$\mu ^\star $$ defined on the whole power set... 相似文献