Hughesstein4665

As proof of concept, we compute the transition state that leads to the formation of hydrogen peroxide during cryptochrome's reoxidation reaction. Last, we show that the construction of the full QM/MM hessian scales linearly with the MM subsystem size.The electronic Raman scattering (ERS) features of single-walled carbon nanotubes (SWNTs) can reveal a wealth of information about their electronic structures. Previously, the ERS processes have been exclusively reported in metallic SWNTs (M-SWNTs) and attributed to the inelastic scattering of photoexcited excitons by a continuum of low-energy electron-hole pairs near the Fermi level. Therefore, the ERS features have been thought to appear exclusively in M-SWNTs but not in semiconducting SWNTs (S-SWNTs), which are more desired in many application fields such as nanoelectronics and bioimaging. In this work, the experimental observation of the ERS features in suspended S-SWNTs is reported, the processes of which are accomplished via the available high-energy electron-hole pairs. The excitonic transition energies with an uncertainty in the order of ±1 meV can be directly obtained via the ERS spectra, compared to a typical uncertainty of ±10 meV in conventional electronic spectroscopies. The ERS features can facilitate further systematic studies on the properties of SWNT, both metallic and semiconducting, with defined chirality.Two brominated 10,10-dimethylisocorrole (10-DMIC) derivatives containing Pd(II) centers have been prepared and characterized. These compounds were prepared via bromination of 10,10-dimethylbiladiene-based oligotetrapyrroles. Bromination of free base 10,10-dimethylbiladiene (DMBil1) followed by metalation with Pd(OAc)2, as well as bromination of the corresponding Pd(II) dimethylbiladiene complex (Pd[DMBil1]) provide routes to Pd(II) hexabromo-10,10-dimethyl-5,15-bis(pentafluorophenyl)-isocorrole (Pd[10-DMIC-Br6]) and Pd(II) octabromo-10,10-dimethyl-5,15-bis(pentafluorophenyl)-isocorrole (Pd[10-DMIC-Br8]). The solid-state structures of the two brominated isocorrole complexes are presented, as is that for a new decabrominated dimethylbiladiene derivative (DMBil-Br10). The electronic and spectroscopic properties of the brominated biladiene and isocorrole derivatives were probed using a combination of voltammetric methods and steady-state UV-vis absorption and emission experiments. Data obtained from these experimations other than singlet oxygen sensitization.N-Nitrosamine disinfection byproducts (DBPs) are a health concern because they are probable human carcinogens. Complex organic nitrogenous compounds, nitrosamine precursors, are largely unidentified in source water. Using stable isotopic labeling-enhanced nontargeted analysis, we identified a natural product N-heterocyclic amine 1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (MTCCA) in source water. Interestingly, we discovered that chloramination of MTCCA-containing water could produce four nitrosamines methylethylnitrosamine, N-nitrosopyrrolidine, N-nitrosoanatabine, and N-nitrosoanabasine. Computational modeling and experimental results helped explain potential pathways of nitrosamines generated from chloramination of MTCCA. Further investigations confirmed widespread occurrence of MTCCA in source water and wastewater. Its concentration ranged from high in upstream creeks (23.2-332.2 ng L-1) to low in the river (5.7-37.6 ng L-1) during the 2020 spring runoffs, indicating that sources of MTCCA came from creeks around farms. learn more Analysis of wastewater before and after ultraviolet, as well as microfiltration with subsequent ozonation treatments, showed increased MTCCA after treatments, demonstrating a difficulty to degrade and remove MTCCA in water. This study discovered the extensive presence of MTCCA in source water and wastewater, suggesting that natural N-heterocyclic compounds may serve as a new source of nitrosamine precursors.The interfacial chemical reactivity of Jahn-Teller-active transition-metal oxides remains an enigmatic area, often leading to uncontrollable phase transformations in the oxide-based technological applications. In particular, the higher tendency of unwanted transition-metal-ion dissolution and side-reactions in Jahn-Teller-active oxides is accompanied by performance degradation in many electrochemical systems, for example, lithium-ion batteries. We show here that the fundamental electronic structure instability that leads to Jahn-Teller (lattice) distortion in an octahedral ligand field is the active chemical driving force for the spontaneous disproportionation, phase transformation, and metal-ion dissolution in transition-metal oxides upon exposure to protons. On the basis of electronic structure analyses and 18O isotope labeling, we present a mechanism comprising a coupled acid-base/redox reaction that leads to a proton-induced disproportionation of Jahn-Teller-active transition-metal ions, as exemplified by the broad classes of respective oxides.Phenolic acids and tanshinones are active principles in Salvia miltiorrhiza Bunge administered for cardiovascular and cerebrovascular diseases. Jasmonic acid (JA) promotes secondary metabolite accumulation, but the regulatory mechanism is unknown in S. miltiorrhiza. We identified and characterized the JA-responsive gene SmMYB97. Multiple sequence alignment and phylogenetic tree analyses showed that SmMYB97 was clustered with AtMYB11, AtMYB12, and ZmP1 in the subgroup S7 regulating flavonol biosynthesis. SmMYB97 was highly expressed in S. miltiorrhiza leaves and induced by methyl jasmonate (MeJA). SmMYB97 was localized in the nucleus and had strong transcriptional activation activity. SmMYB97 overexpression increased phenolic acid and tanshinone biosynthesis and upregulated the genes implicated in these processes. Yeast one-hybrid and transient transcriptional activity assays disclosed that SmMYB97 binds the PAL1, TAT1, CPS1, and KSL1 promoter regions. SmJAZ8 interacts with SmMYB97 and downregulates the genes that it controls. This study partially clarified the regulatory network of MeJA-mediated secondary metabolite biosynthesis in S. miltiorrhiza.