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排序方式: 共有272条查询结果,搜索用时 31 毫秒
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Giuseppina La Ganga Fausto Puntoriero Enza Fazio Mirco Natali Francesco Nastasi Antonio Santoro Maurilio Galletta Sebastiano Campagna 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(68):16904-16911
The luminophore Ru(bpy)2(dcbpy)2+ (bpy=2,2’-bipyridine; dcbpy=4,4’-dicarboxy-2,2’-bipyridine) is covalently linked to a chitosan polymer; crosslinking by tripolyphosphate produced Ru-decorated chitosan fibers (NS-RuCh), with a 20 : 1 ratio between chitosan repeating units and RuII chromophores. The properties of the RuII compound are unperturbed by the chitosan structure, with NS-RuCh exhibiting the typical metal-to-ligand charge-transfer (MLCT) absorption and emission bands of RuII complexes. When crosslinks are made in the presence of IrO2 nanoparticles, such species are encapsulated within the nanofibers, thus generating the IrO2⊂NS-RuCh system, in which both RuII photosensitizers and IrO2 water oxidation catalysts are within the nanofiber structures. NS-RuCh and IrO2⊂NS-RuCh have been characterized by dynamic light scattering, scanning electronic microscopy, and energy-dispersive X-ray analysis, which indicated a 2 : 1 ratio between RuII chromophores and IrO2 species. Photochemical water oxidation has been investigated by using IrO2⊂NS-RuCh as the chromophore/catalyst assembly and persulfate anions as the sacrificial species: photochemical water oxidation yields O2 with a quantum yield (Φ) of 0.21, definitely higher than the Φ obtained with a similar solution containing separated Ru(bpy)32+ and IrO2 nanoparticles (0.05) or with respect to that obtained when using NS-RuCh and “free” IrO2 nanoparticles (0.10). A fast hole-scavenging process (rate constant, 7×104 s−1) involving the oxidized photosensitizer and the IrO2 catalyst within the IrO2⊂NS-RuCh system is behind the improved photochemical quantum yield of IrO2⊂NS-RuCh. 相似文献
3.
Andrea Giuntoli Nicola Calonaci Sebastiano Bernini Dino Leporini 《Journal of Polymer Science.Polymer Physics》2017,55(23):1760-1769
The relation between elasticity and yielding is investigated in a model polymer solid by Molecular‐Dynamics simulations. By changing the bending stiffness of the chain and the bond length, semicrystalline and disordered glassy polymers — both with bond disorder — as well as nematic glassy polymers with bond ordering are obtained. It is found that in systems with bond disorder the ratio τY/G between the shear yield strength τY and the shear modulus G is close to the universal value of the atomic metallic glasses. The increase of the local nematic order in glasses leads to the increase of the shear modulus and the decrease of the shear yield strength, as observed in experiments on nematic thermosets. A tentative explanation of the subsequent reduction of the ratio τY/G in terms of the distributions of the per‐monomer stress is offered. © 2017 Wiley Periodicals, Inc. J. Polym. Sci. Part B: Polym. Phys. 2017 , 55, 1760–1769 相似文献
4.
D. Petroni M. Poli L. Campisi P. A. Salvadori L. Menichetti 《Journal of Radioanalytical and Nuclear Chemistry》2012,293(3):757-762
Positron Emission Tomography has become increasingly relevant in clinical practice for diagnostic purposes. A major concern regarding radiopharmaceuticals in general is how quality requirements can be guaranteed in nuclear medicine departments or in cases where marketing authorization has been granted. This article focuses on issues related to the small-volume preparation of radiopharmaceuticals by a Research Institute after Good Manufacturing Practice implementation. 相似文献
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Giuliana Cangemi Sebastiano Barco Roberto Bandettini Elio Castagnola 《Analytical and bioanalytical chemistry》2014,406(6):1795-1798
Micafungin (MCF) is an antifungal agent of the echinocandin class approved in Europe both in adults and in children for the treatment of invasive candidiasis. Few analytical methods for therapeutic drug monitoring (TDM) of this drug have been described so far. In this paper, we describe a rapid and validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for the measurement of MCF in plasma. MCF was analyzed in 100-μL plasma samples over a wide range of concentrations (0.1–20 μg/mL) by LC-MS/MS after protein precipitation. The suitability of the assay for TDM was evaluated by using plasma samples from pediatric patients who received MCF for the treatment of invasive candidiasis. The overall turnaround time for the assay was 20 min. The lower limit of quantification of the method was 0.1 ng/mL. No ion suppression due to matrix effects was found with different pre-analytical conditions, such as hemolysis, lipemia, and hyperuricemia. A simple and rapid LC-MS/MS method which provides high specificity, precision, and accuracy for quantification of MCF in plasma has been developed and validated. 相似文献
7.
Giuseppe Gattuso Sebastiano Pappalardo Melchiorre F. Parisi Ilenia Pisagatti 《Supramolecular chemistry》2014,26(7-8):597-600
The molecular recognition in water of neurotransmitter monoamine and trace amine hydrochlorides by p-tert-butylcalix[5]-arene 1 – bearing 4-sulphonatobutoxy groups at the lower rim – has been investigated. According to 1H NMR measurements, the hydrophobic cavity of receptor 1 best binds tyramine hydrochloride, Ka = 5370 ± 870 M? 1. 相似文献
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We address the problem of observables in generally invariant spacetime theories such as Einstein’s general relativity. Using
the refined notion of an event as a “point-coincidence” between scalar fields that completely characterise a spacetime model,
we propose a generalisation of the relational local observables that does not require the existence of four everywhere invertible
scalar fields. The collection of all point-coincidences forms in generic situations a four-dimensional manifold, that is naturally
identified with the physical spacetime. 相似文献
10.
Let ℱ be a local net of von Neumann algebras in four spacetime dimensions satisfying certain natural structural assumptions.
We prove that if ℱ has trivial superselection structure then every covariant, Haag-dual subsystem ℬ is of the form ℱ1
G
⊗I for a suitable decomposition ℱ=ℱ1⊗ℱ2 and a compact group action. Then we discuss some application of our result, including free field models and certain theories
with at most countably many sectors.
Received: 26 January 2000 / Accepted: 28 September 2000 相似文献