Search

Summary: High‐quality genome of rosemary (Salvia rosmarinus) represents a valuable resource and tool for understanding genome evolution and environmental adaptation as well as its genetic improvement. However, the existing rosemary genome did not provide insights into the relationship between antioxidant components and environmental adaptability. In this study, by employing Nanopore sequencing and Hi‐C technologies, a total of 1.17 Gb (97.96%) genome sequences were mapped to 12 chromosomes with 46 121 protein‐coding genes and 1265 non‐coding RNA genes. Comparative genome analysis reveals that rosemary had a closely genetic relationship with Salvia splendens and Salvia miltiorrhiza, and it diverged from them approximately 33.7 million years ago (MYA), and one whole‐genome duplication occurred around 28.3 MYA in rosemary genome. Among all identified rosemary genes, 1918 gene families were expanded, 35 of which are involved in the biosynthesis of antioxidant components. These expanded gene families enhance the ability of rosemary adaptation to adverse environments. Multi‐omics (integrated transcriptome and metabolome) analysis showed the tissue‐specific distribution of antioxidant components related to environmental adaptation. During the drought, heat and salt stress treatments, 36 genes in the biosynthesis pathways of carnosic acid, rosmarinic acid and flavonoids were up‐regulated, illustrating the important role of these antioxidant components in responding to abiotic stresses by adjusting ROS homeostasis. Moreover, cooperating with the photosynthesis, substance and energy metabolism, protein and ion balance, the collaborative system maintained cell stability and improved the ability of rosemary against harsh environment. This study provides a genomic data platform for gene discovery and precision breeding in rosemary. Our results also provide new insights into the adaptive evolution of rosemary and the contribution of antioxidant components in resistance to harsh environments. [ABSTRACT FROM AUTHOR]

Compressive strain, downshifting the d-band center of transition metal oxides, is an effective way to accelerate the sluggish kinetics of oxygen evolution reaction (OER) for water electrolysis. Here, we find that anisotropic thermal expansion can produce compressive strains of the IrO6 octahedron in Sr2IrO4 catalyst, thus downshifting its d-band center. Different from the previous strategies to create constant strains in the crystals, the thermal-triggered compressive strains can be real-timely tuned by varying temperature. As a result of the thermal strain accelerating OER kinetics, the Sr2IrO4 exhibits the nonlinear lnjo - T−1 (jo, exchange current density; T, absolute temperature) Arrhenius relationship, resulting from the thermally induced low-barrier electron transfer in the presence of thermal compressive strains. Our results verify that the thermal field can be utilized to manipulate the electronic states of Sr2IrO4 via thermal compressive strains downshifting the d-band center, significantly accelerating the OER kinetics, beyond the traditional thermal diffusion effects. Tuning compressive strain is an effective way to accelerate the oxygen evolution reaction kinetics. Here the authors show that anisotropic thermal expansion induces compressive strains on IrO6 octahedron in Sr2IrO4, shifting its d-band center downward and accelerating water oxidation kinetics beyond traditional thermal diffusion effects. [ABSTRACT FROM AUTHOR]

Compressive strain, downshifting the d-band center of transition metal oxides, is an effective way to accelerate the sluggish kinetics of oxygen evolution reaction (OER) for water electrolysis. Here, we find that anisotropic thermal expansion can produce compressive strains of the IrO6 octahedron in Sr2IrO4 catalyst, thus downshifting its d-band center. Different from the previous strategies to create constant strains in the crystals, the thermal-triggered compressive strains can be real-timely tuned by varying temperature. As a result of the thermal strain accelerating OER kinetics, the Sr2IrO4 exhibits the nonlinear lnjo - T−1 (jo, exchange current density; T, absolute temperature) Arrhenius relationship, resulting from the thermally induced low-barrier electron transfer in the presence of thermal compressive strains. Our results verify that the thermal field can be utilized to manipulate the electronic states of Sr2IrO4 via thermal compressive strains downshifting the d-band center, significantly accelerating the OER kinetics, beyond the traditional thermal diffusion effects.Tuning compressive strain is an effective way to accelerate the oxygen evolution reaction kinetics. Here the authors show that anisotropic thermal expansion induces compressive strains on IrO6 octahedron in Sr2IrO4, shifting its d-band center downward and accelerating water oxidation kinetics beyond traditional thermal diffusion effects. [ABSTRACT FROM AUTHOR]

An effective pathway to cope with the sluggish oxygen evolution reaction (OER) is to accelerate the electron transfer kinetics. Transition metal with high valence states doping can accelerate the reaction kinetics to afford high inherent activity. Herein, a novel trimetallic NiFeCr nanoalloy as an OER electrocatalyst is synthesized by replacing partial Fe in the Ni3Fe alloy with Cr. In the OER process, Cr leached from the surface layer of the NiFeCr alloy to form a core–shell NiFeCr@NiFeOOH structure. The electrons from the OER intermediates were significantly accelerated by the high-valence Cr6+ as an electron acceptor at the core–shell interface. As a result, NiFeCr@NiFeOOH exhibited excellent OER performances with a low overpotential of 209 mV at 25 mA cm−2 in 1.0 M KOH on conductive carbon paper, outperforming the Ni3Fe alloy without Cr doping. Our work provides a new strategy to design and synthesize the NiFe-based alloy with high OER activity. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) and selenium (Se) could jointly affect plant growth. To investigate the affect of Se on the Cd accumulation in Juglans regia and the physiological mechanism by which Se regulates Cd-induced oxidative stress, in this study, the effects of different foliar application doses of Se (0 (Se0), 20 (Se20), and 200 (Se200) μM) on J. regia (variety Xinfeng) seedlings under Cd stress (5 mM) were determined. The results show that exogenous application of Se (Se20 and Se200) increased walnut biomass compared with Se0 under Cd stress. Under Cd stress, exogenous application of 20 μM Se increased the catalase (CAT), peroxidase (POD), and ascorbate oxidase (AAO) activities in walnut roots and the CAT and AAO activities in walnut leaves, and exogenous application of 200 μM Se increased the CAT, POD, and AAO activities in walnut roots. Furthermore, under Cd stress, exogenous application of 20 and 200 μM Se both decreased the contents of superoxide (O2•−), hydrogen peroxide (H2O2), and malondialdehyde (MDA) in walnut roots and the content of MDA in walnut leaves. Moreover, application of 20 and 200 μM Se both reduced the accumulation of Cd in the root, wood, bark, and leaves of walnuts, and application of 200 μM Se enhanced Se concentration in the root, wood, bark, and leaves. Overall, exogenous application of Se, especially 200 μM Se, could reduce Cd accumulation and enhance CAT, POD, and AAO activities in Cd-stressed walnut roots, thus alleviating Cd stress. This study provides technical guidance for reducing the effects of Cd stress on walnut growth. [ABSTRACT FROM AUTHOR]

Redox couple oxidation as an initial step of water oxidation may be key for high electricity consumption in the electrochemical oxygen evolution reaction (OER). Here, a heat‐induced magnetic transition strategy is reported to speed up the oxidation kinetics of redox couples. The activation energy of Ni2+/Ni3+ redox couple oxidation is sharply decreased by heating the Ni0.67Fe0.33OxHy catalyst above a Curie temperature (Tc) of 70 °C. In such a strategy, heat instead of electricity drives the spin flipping of Ni2+/Ni3+ oxidation through heat‐sensitive ferri‐to‐paramagnetic spin state changes. As a result of magnetic transition‐assisted efficient heat‐electricity coupling, Ni0.67Fe0.33OxHy exhibits the lowest OER overpotential of 221 mV at 100 mA cm−2 at 90 °C in alkaline electrolytes, outperforming the benchmark IrO2 catalyst. The findings provide new insights into the design of efficient heat–electricity complementary OER devices. [ABSTRACT FROM AUTHOR]

Accelerating electron transfer kinetics is an efficient strategy to tackle the sluggish oxygen evolution reaction (OER). Herein, Ni3Fe1−xVx/Ni3Fe1−xVxN heterojunctions were elaborately constructed to demonstrate that the coupling of variable-valence metal doping and nanoalloy/nitride heterointerfaces could optimize the OER performance of antiperovskite nitrides. The spectroscopic results suggested that during OER electrochemical surface reconstruction occurred to form an assembly of a crystalline Ni3Fe1−xVx/Ni3Fe1−xVxN heterojunction core and amorphous NiFeOOH shell (Ni3Fe1−xVx/Ni3Fe1−xVxN@NiFeOOH). The electron transfer from the OER intermediates via the amorphous NiFeOOH shell was efficiently accelerated by the variable-valence V3+/4+ electron acceptor at the core@shell interface and the heterojunction effect in the Ni3Fe1−xVx/Ni3Fe1−xVxN core. As a result, the oxygen and hydrogen evolution reactions can occur at low overpotentials of 260 mV at 50 mA cm−2 and 113 mV at 10 mA cm−2, respectively, affording a low cell voltage of 1.66 V at 10 mA cm−2 for water splitting in alkaline electrolyte (1.0 M KOH). Our results provide a new attempt at improving water splitting kinetics via the variable-valence ion coupling heterojunction effect. [ABSTRACT FROM AUTHOR]

An efficient and low-cost oxygen evolution reaction (OER) electrocatalyst is key for electrochemical energy conversion and storage technologies. However, there is a lack of a strategy to guide the development of cost-effective antiperovskite nitrides with composition-sensitive function adjustability. Herein, we triggered the low-spin to high-spin transition of Fe3+ in Cu0.5NFe3.5 by partially doping Ni at the Fe sites, enabling Cu0.5NFe3Ni0.5 to significantly accelerate the oxidation of the in situ electrochemically formed amorphous FeNi (oxy)hydroxide redox couple, an initial water oxidation step, as well as subsequent water oxidation. Theoretical calculations indicated that the high-spin Fe3+ induces the formation of a paramagnetic FeNi (oxy)hydroxide catalytic layer on the ferromagnetic Cu0.5NFe3Ni0.5 core to accelerate the OER kinetics, thus Cu0.5NFe3Ni0.5 displays an overpotential of 244 mV at 10 mA cm−2 as an outstanding OER electrocatalyst, outperforming the benchmark IrO2 catalyst. Our findings are expected to unlock the potential of designing ideal antiperovskite-based electrocatalysts with adjustable spin states for use in the energy conversion and storage fields. [ABSTRACT FROM AUTHOR]

In this study, a series of molybdenum-doped ultrathin BiVO4 nanosheets (Mo-BVO) were successfully synthesized by a facile hydrothermal method. The results indicated that Mo-BVO nanosheets exhibited high photocatalytic efficiency of methyl blue (MB) degradation under visible-light irradiation. Particularly, 1% Mo-BVO exhibited an optimum photo-degradation rate of more than 97% within 60 min under visible-light illumination, which was approximately 3.8 times greater than that of pure BVO. The experimental characterizations and DFT calculations manifested that the ultrathin BVO nanosheets and Mo doping were beneficial to provide abundant active sites, suppress the photoinduced charge recombination and extend the absorption visible-light range, thus enhancing the photocatalytic performance toward MB degradation. Additionally, the photocatalytic reaction mechanism was proposed based on the reactive species trapping experiments. This study was expected to design a highly active photocatalyst for pollution decomposition by modulating the photocatalytic properties and electronic band structure. [ABSTRACT FROM AUTHOR]

The influences of a series of (N, Mo, W) monodoping and N-Mo(W) codoping on the electronic structures of sodium niobate have been systematically investigated by density functional theory (DFT) calculations with the hybrid B3LYP functional. The results indicated that some localized N 2 p states were formed above the top of valence band (VB) after N-doping. In the case of Mo(W)-doping, the position of VB shifted up, meanwhile, the hybridization of Nb 4 d and Mo 4 d(W 5 d) states moved the conduction band (CB) downward, leading to narrowing the band gap. As for N-Mo codoped NaNbO3, the localized Mo 4 d states were formed near the bottom of CB while the localized N 2 p states appeared above the top of VB. When N-W codoping, the W 5 d p states mixed with Nb 4 d states and then moved the top of CB downward as well as some localized N 2 p states were formed above the valence band (O 2 p), leading to the obvious reduction of the photon transition energy compared with that of NaNbO3. [ABSTRACT FROM AUTHOR]

A simple ratiometric electrochemical biosensor is developed for sensitive detection of target DNA based on DNA four-way junction (DNA-4WJ) formation and enzyme-assisted recycling amplification. This biosensor can be easily fabricated by a one-step assembly of ratiometric probes and simply performed by a one-step incubation procedure. In the presence of target DNA, two unmodified DNA oligonucleotides may cooperatively hybridize with a hairpin probe in the triple-helix molecular beacon (THMB) to form a DNA-4WJ, which may cause conformational transduction and induce the change in the distance between two redox labeling probes and the electrode surface. The subsequent recognition and cleavage of DNA-4WJ quadripartite complexes by RNase HII may result in significant signal amplification. Due to the introduction of DNA-4WJ formation, enzyme-assisted recycling amplification and ratiometric measurement, this biosensor exhibits high sensitivity with a detection limit as low as 0.063 pM and a long dynamic range from 0.1 pM to 100 nM. Moreover, this biosensor demonstrates good performance with excellent selectivity, high reliability and good reproducibility, holding great potential for further applications in biomedical research and clinical diagnostics. [ABSTRACT FROM AUTHOR]