The development of fluorescent probes for nitroreductase (NTR) has received intense attention because of its biological significance and wide application. In this work, a novel fluorescent probe for the detection of NTR in aqueous solution was designed and synthesized on a 1,8-naphthalimide scaffold. In the presence of NTR and nicotinamide adenine dinucleotide (NADH) under physiological conditions, the probe was converted into a 4-hydroxy-1,8-naphthalimide derivative and exhibited a sharp fluorescence enhancement at 550 nm, with a high selectivity for NTR over various analytes. The detection limit for NTR was determined to be 9.8 ng/ml by this probe. Due to its low signal background, this probe showed?>?70-fold fluorescence enhancement. Theoretical calculations revealed that the reason for the fluorescence quenching of this probe is the photoinduced electron transfer (PET) from both the nitrobenzene and morpholine groups to the naphthalimide fluorophore.
Nonlinear Dynamics - This paper is first of the two papers dealing with the nonlinear modelling and investigation of coupled cross-flow and in-line vortex-induced vibrations (VIVs) of flexible... 相似文献
Three new metal complexes, namely: [Mn(AIDB)Cl2]·DMF (1), [Zn(AIDB)Br2]·CH3OH (2) and [Co(AIDB)Cl2]·CH3OH (3) having a ligand bis(benzimidazol-2-ylmethyl)allylamine (AIDB), have been synthesized in high yields and characterized by elemental analyses, molar conductivities, IR, UV–Vis spectra and single-crystal X-ray diffraction. The structural analysis revealed that all the three complexes 1–3 have five-coordinated trigonal bipyramid geometry where the degree of distorting is 1>3>2. In vitro antioxidant activity assay demonstrates that the complexes 1 and 3 display high scavenging activity against hydroxyl (OH·) and superoxide (O2−·) radicals.
Sponges, Neofibularia nolitangere, can regenerate spontaneously after being broken down into small pieces, and the regenerated structure maintains the original appearance and function. Synthetic materials with such capabilities are highly desired but hardly achieved. Presented here is a sponge‐inspired self‐regenerative powder from a double‐network (DN) tough hydrogel. Hydrogels are regenerated from their powder form, by addition of water, with preservation of the original appearance and mechanical properties. The powder‐hydrogel‐powder cycle can be repeated multiple times with little loss in mechanical properties, analogous to the regeneration of sponges. These DN hydrogels can be conveniently stored and easily shaped upon regeneration. This work may have implications in the development of regenerative materials for coatings and adhesives. 相似文献
Littordial F (1), a novel meroterpenoid with an unique 6/8/9/4-tetracyclic nucleus, was isolated from the leaves of Psidium littorale. The structure of 1 was established by spectroscopic data, and its absolute configuration was confirmed by computational 13C NMR and optical rotation data. Compound 1 exhibited potential cytotoxic activities on A549, B16, and HepG-2 cell lines. A plausible biosynthetic pathway for littordial F was proposed. 相似文献