The o-quinone forms of 2,3- and 3,4-catechol estrogens have been implicated in the carcinogenicity of these hormones. The concomitant production of reactive oxygen species during reduction of the o-quinone estrogens has been inferred to play a mechanistic role in their mutagenic potential. Conclusive evidence documenting the production of hydrogen peroxide, the hydroxyl radical, and the estrone 3,4-semiquinone in estrone 3,4-quinone (3,4-EQ)-treated human breast cancer subcellular fractions was demonstrated in the absence of exogenously added catalysts. Subcellular fractions of MCF-7 cells treated with 3,4-EQ and NADPH, including nuclei, mitochondria, and microsomes, were shown to support significant amounts of hydrogen peroxide production. Hydrogen peroxide production in 3,4-EQ-treated cellular fractions and the chromosomal DNA damage induced in 3,4-EQ-treated MCF-7 cells were abolished by the addition of catalase. A significant and potentially physiologically relevant spontaneous reduction of 3,4-EQ by NADPH resulting in hydrogen peroxide production was demonstrated. The results unequivocally demonstrate that free radicals are produced during the metabolism of estrone 3,4-quinone in human cells.
More and more attention has been paid to environmentally friendly bio-based renewable materials as the substitution of fossil-based materials, due to the increasing environmental concerns. In this study, regenerated cellulose films with enhanced mechanical property were prepared via incorporating different plasticizers using ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl) as the solvent. The characteristics of the cellulose films were investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM), thermal analysis (TG), X-ray diffraction (XRD), 13C Solid-state cross-polarization/magic angle spinning nuclear magnetic resonance (CP/MAS NMR) and tensile testing. The results showed that the cellulose films exhibited a homogeneous and smooth surface structure. It was noted that the thermal stability of the regenerated cellulose film plasticized with glycerol was increased compared with other regenerated cellulose films. Furthermore, the incorporation of plasticizers dramatically strengthened the tensile strength and improved the hydrophobicity of cellulose films, as compared to the control sample. Therefore, these notable results exhibited the potential utilization in producing environmentally friendly cellulose films with high performance properties.
Lignin, a byproduct of the wood-pulping industry, is mostly treated as a noncommercialized waste product. Therefore, it is significant to study its potential for the conversion of this renewable and sustainable resource into high-valued chemicals and materials. In this study, a renewable lignin-based material with high performance in wastewater treatment has been explored on account of its satisfactory properties and being environmentally friendly. Herein, lignin hollow microspheres (LHM) were facilely prepared from esterified organosolv lignin with maleic anhydride (MA) via self-assembly in the mixed tetrahydrofuran−Fe 3 O 4 nanoparticles aqueous media. Moreover, the magnetic lignin spheres (MLS) were also successfully fabricated by introducing Fe 3 O 4 nanoparticles. The structural changes of esterified lignin polymers were identified and morphology and property of obtained LHM and MLS were characterized by means of TEM, SEM, VSM and FT-IR. In addition, the adsorption capacities of MLS for methylene blue and Rhodamine B from aqueous solutions were also comparatively investigated. It was observed from SEM and TEM images that the LHM from larch lignin exhibited uniform spherical and dense surface, but that from poplar lignin was not rigid enough to keep the perfect spherical shape and partially collapsed. The adsorption capacity results showed that the MLS from larch lignin exhibited better adsorption properties for methylene blue (31.23 mg/g) and Rhodamine B (17.62 mg/g) than that from poplar lignin (25.95 and 15.79 mg/g, respectively). Simultaneously, the adsorption kinetics and adsorption isotherm experiments indicated that the data were agreed well with the pseudo-second-order and Langmuir model, respectively. Moreover, after three cycles of desorption, the removal efficiencies of the MLS from larch and poplar lignin could still reach more than 98% and 96%, respectively. Therefore, the developed magnetic lignin-based hollow microspheres has shown a great potential as a low-cost, highly adsorptive and reusable adsorbent for the applications in the wastewater treatments.
In the present study, two kinds of deep eutectic solvents (DESs) were facilely prepared and adopted to drastically disturb the recalcitrance of corncobs for further boosting sugar yields and obtaining valorized lignin by-products while reducing treatment times.
The demand for substitution of fossil-based materials by renewable bio-based materials is increasing with the fossil resources reduction and its negative impacts on the environment. In this study, environmentally friendly regenerated cellulose films were successfully prepared using 1-allyl-3-methylimidazolium chloride (AmimCl), 1-butyl-3-methylimidazolium chloride (BmimCl), 1-ethyl-3-methylimidazolium chloride (EmimCl), and 1-ethyl-3-methylimidazolium acetate (EmimAc) as solvents, respectively. The results of morphology from scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed that all the cellulose films possessed smooth, highly uniform, and dense surface. The solid-state cross-polarization/magic angle spinning (CP/MAS)13C NMR spectra and X-ray diffraction (XRD) corroborated that the transition from cellulose I to II had occurred after preparation. Moreover, it was shown that the ionic liquid EmimAc possessed much stronger dissolubility for cellulose as compared with other ionic liquids and the cellulose film regenerated from EmimCl exhibited the most excellent tensile strength (119 Mpa). The notable properties of regenerated cellulose films are promising for applications in transparent biodegradable packaging and agricultural purpose as a substitute for PP and PE.
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