173 publications from this institution
Understanding towards chain-breaking antioxidants as potent inhibitors of lipid peroxyl radicals, high-throughput efforts have been investigated for antioxidant behaviour of 6-bromo-3,3-dimethyl-8 hexadecyltelluro [1,3]dioxepino[5,6-c]pyridin-9-ol and 2-methyl-2,3-dihydrobenzo[b]selenophene-5-ol in the two phase (chlorobenzene/water) lipid peroxidation model system at various pH 1-7 and mild co-antioxidants such as (glutathione, dithiothreitol, ascorbic acid, sodium ascorbate, and potassium hexacyanoferrate(II) trihydrate, sodium metasulfite, and tris(2-carboxyethyl)phosphine hydrochloride). The key chain-breaking mechanism profile was attributed towards the first oxygen transfer atom from the lipid peroxyl radical to the Se/Te atoms and then hydrogen atom transfer from the nearby phenolic group by the alkoxyl radical due to the weak O-H bond dissociation energy in the solvent cage. Finally, the regeneration could take place by the presence of aqueous soluble co-antioxidants that increased the inhibition time of antioxidants more efficiently than α-tocopherol. Tellurium analouge at pH 2-5 in presence of N -acetylcysteine offered better protection for chain-breaking capacity than the selenium analouge. In the presence of aqueous soluble N -acetylcysteine at pH 1-7, both antioxidants in the present study behaved very good inhibitors of lipid peroxyl radicals.
We report a new excited‐state intramolecular proton transfer (ESIPT)‐inspired hydroxyl (OH)‐substituted pyrene‐imidazole that promote unprecedented intramolecular proton transfer in the ground state (GSIPT). The enol and keto isomers are in equilibrium, with a high keto‐isomer component in the solid state. In conjunction with DFT calculations, the photophysical studies and crystal structure analysis shred substantial evidence for the ground state transformation. The ESIPT‐active compounds also show the rare feature of high dual solution (φ f =70 %) and solid state (φ f =41 %) emission characteristics and counter‐intuitive stronger intermolecular interactions in the solid state versus the ESIPT‐inactive counterparts.
This review intends to provide an overview of bacterial degradation of nitrophenols (NPs) and their derivatives. The main scientific focus is on biochemical and genetic characterization of bacterial degradation of NPs. Other aspects such as bioremediation and chemotaxis correlated with biodegradation of NPs are also discussed. This review will increase our current understanding of bacterial degradation of NPs and their derivatives.
In an effort to improve the chain-breaking capacity of the natural antioxidants, an octyltelluro group was introduced next to the phenolic moiety in β- and δ-tocopherol. The new vitamin E analogues quenched peroxyl radicals more efficiently than α-tocopherol and were readily regenerable by aqueous N-acetylcysteine in a simple membrane model composed of a stirring chlorobenzene/water two-phase system. The novel tocopherol analogues could also mimic the action of the glutathione peroxidase enzymes.
Singlet Fission (SF) into two triplets offers exciting avenues for high-efficiency photovoltaics and optically initializable qubits. While the chemical space of SF chromophores is ever-expanding, the mechanistic details of electronic-nuclear motions that dictate the photophysics are unclear. Rigid SF dimers with well-defined orientations are necessary to decipher such details. Here, using polarization-controlled white-light two-dimensional and pump-probe spectroscopies, we investigate a new class of contorted naphthalenediimide dimers, recently reported to have a favorable intramolecular SF (iSF) pathway. 2D cross-peaks directly identify the two Davydov components of the dimer along with strongly wavelength-dependent TT1 formation kinetics depending on which Davydov component is excited, implicating a coherently coupled intermediate that mediates iSF. Enhanced quantum beats in the TT1 photoproduct suggest that inter-chromophore twisting and ruffling motions drive the ~200 fs evolution towards an excimer-like intermediate and its subsequent ~2 ps relaxation to the TT1 photoproduct. Polarization anisotropy directly tracks electronic motion during these steps and reveals surprisingly minimal electronic reorientation with significant singlet-triplet mixing throughout the nuclear evolution away from the Franck-Condon geometry towards relaxed TT1. The observations of coherent excimer-like intermediate and significant singlet-triplet mixing throughout the iSF process need to be carefully accounted for in the synthetic design and electronic structure models for iSF dimers aiming for long-lived high-spin correlated triplets.
Allocation and management of agricultural water resources is an emerging concern due to diminishing water supplies and increasing water demands. To achieve economic, social, and environmental goals in a specific irrigation district, decisions should be made subject to the changing water supply and water demand—the two critical random parameters in agricultural water resources management. This paper presents the foundations of a systematic framework for agricultural water resources management, including determination of distribution functions, joint probability of water supply and water demand, optimal allocation of agricultural water resources, and evaluation of various schemes according to agricultural water resources carrying capacity. The maximum entropy method is used to estimate parameters of probability distributions of water supply and demand, which is the basic for the other parts of the framework. The entropy-weight-based TOPSIS method is applied to evaluate agricultural water resources allocation schemes, because it avoids the subjectivity of weight determination and reflects the dynamic changing trend of agricultural water resources carrying capacity. A case study using an irrigation district in Northeast China is used to demonstrate the feasibility and applicability of the framework. It is found that the framework works effectively to balance multiple objectives and provides alternative schemes, considering the combinatorial variety of water supply and water demand, which are conducive to agricultural water resources planning.
The reaction of selenides (I) with bromine and subsequent treatment of the brominated intermediate with Et 3 N leads to novel photoluminescent selenospirocycles (II).
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
A better understanding of the effects of climate change and land use/cover change (LUCC) on streamflow promotes the long-term water planning and management in the arid regions of northwestern China. In this paper, the Soil and Water Assessment Tool (SWAT) and a separation approach were used to evaluate and separate the effects of climate change and LUCC on streamflow in the Xiying River basin. The SWAT model was calibrated by the hydro-meteorological data from 1980–1989 to obtain the optimum parameters, which were validated by the subsequent application to the period between 1990–2008. Moreover, streamflow under several scenarios with different climate change and land use conditions in 1990–2008 and 2010–2069 were further investigated. Results indicate that, in the period of 1990–2008, the streamflow was dominated by climate change (i.e., changes in precipitation and temperature), which led to a 102.8% increase in the mean annual streamflow, whereas LUCC produced a decrease of 2.8%. Furthermore, in the future period of 2010–2039, the mean annual streamflow will decrease by 5.4% and 4.5% compared with the data of 1961–1990 under scenarios A2 and B2, respectively, while it will decrease by 21.2% and 16.9% in the period of 2040–2069, respectively.
No abstract is provided for this article.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
