Inorganic perovskite ferroelectrics are widely used in nonvolatile memory elements, capacitors, and sensors because of their excellent ferroelectric and other properties. Organic ferroelectrics are ...desirable for their mechanical flexibility, low weight, environmentally friendly processing, and low processing temperatures. Although almost a century has passed since the first ferroelectric, Rochelle salt, was discovered, examples of highly desirable organic perovskite ferroelectrics are lacking. We found a family of metal-free organic perovskite ferroelectrics with the characteristic three-dimensional structure, among which MDABCO (
-methyl-
-diazabicyclo2.2.2octonium)-ammonium triiodide has a spontaneous polarization of 22 microcoulombs per square centimeter close to that of barium titanate (BTO), a high phase transition temperature of 448 kelvins (above that of BTO), and eight possible polarization directions. These attributes make it attractive for use in flexible devices, soft robotics, biomedical devices, and other applications.
1,4‐Diazabicyclo2.2.2octane (dabco) and its derivatives have been extensively utilized as building units of excellent molecular ferroelectrics for decades. However, the homochiral dabco‐based ...ferroelectric remains a blank. Herein, by adding a methyl (Me) group accompanied by the introduction of homochirality to the H2dabco2+ in the non‐ferroelectric H2dabcoTFSA2 (TFSA=bis(trifluoromethylsulfonyl)ammonium), we successfully designed enantiomeric ferroelectrics R and S‐2‐Me‐H2dabcoTFSA2. The two enantiomers show two sequential phase transitions with transition temperature (Tc) as high as 405.8 K and 415.8 K, which is outstanding in both dabco‐based ferroelectrics and homochiral ferroelectrics. To our knowledge, R and S‐2‐Me‐H2dabcoTFSA2 are the first examples of dabco‐based homochiral ferroelectrics. This finding opens an avenue to construct dabco‐based homochiral ferroelectrics and will inspire the exploration of more eminent enantiomeric molecular ferroelectrics.
The first examples of homochiral dabco‐based (dabco=1,4‐diazabicyclo2.2.2octane) ferroelectrics, R‐ and S‐2‐Me‐H2dabcoTFSA2 (TFSA=bis(trifluoromethylsulfonyl)ammonium), were designed from the non‐ferroelectric H2dabcoTFSA2. They show two phase transitions with a transition temperature (Tc) up to 405.8 K and 415.8 K, higher than the Tc of most dabco‐based or homochiral ferroelectrics.
WRKY transcription factors (TFs) are transcriptional regulators in plants and have a conserved WRKY motif and various zinc-finger structures.WRKY TFs may integrate signals of pathogen-associated ...molecular pattern-triggered immunity and effector-triggered immunity.WRKY genes modulate transcription in plant defense responses against environmental stressors like reactive oxygen species burst, Ca2+ influx, mitogen-activated protein kinase activation, phytohormone production, and epigenetic modification.WRKYs may function as master regulators to balance plant growth and stress response.WRKYs could aid the generation of stress-resilient crops by modern molecular breeding for better crop productivity in the face of climate change.
Environmental stressors caused by climate change are fundamental barriers to agricultural sustainability. Enhancing the stress resilience of crops is a key strategy in achieving global food security. Plants perceive adverse environmental conditions and initiate signaling pathways to activate precise responses that contribute to their survival. WRKY transcription factors (TFs) are essential players in several signaling cascades and regulatory networks that have crucial implications for defense responses in plants. This review summarizes advances in research concerning how WRKY TFs mediate various signaling cascades and metabolic adjustments as well as how epigenetic modifications involved in environmental stress responses in plants can modulate WRKYs and/or their downstream genes. Emerging research shows that clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas)-mediated genome editing of WRKYs could be used to improve crop resilience.
Environmental stressors caused by climate change are fundamental barriers to agricultural sustainability. Enhancing the stress resilience of crops is a key strategy in achieving global food security. Plants perceive adverse environmental conditions and initiate signaling pathways to activate precise responses that contribute to their survival. WRKY transcription factors (TFs) are essential players in several signaling cascades and regulatory networks that have crucial implications for defense responses in plants. This review summarizes advances in research concerning how WRKY TFs mediate various signaling cascades and metabolic adjustments as well as how epigenetic modifications involved in environmental stress responses in plants can modulate WRKYs and/or their downstream genes. Emerging research shows that clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas)-mediated genome editing of WRKYs could be used to improve crop resilience.
Young organisms have relatively strong resistance to diseases and adverse conditions. When confronted with adversity, the process of development is delayed in plants. This phenomenon is thought to ...result from the rebalancing of energy, which helps plants to coordinate the relationship between development and stress tolerance; however, the molecular mechanism underlying this phenomenon remains mysterious. In this study, we found that miR156 integrates environmental signals to ensure timely flowering, thus enabling the completion of breeding. Under stress conditions, miR156 is induced to maintain the plant in the juvenile state for a relatively long period of time, whereas under favorable conditions, miR156 is suppressed to accelerate the developmental transition. Blocking the miR156 signaling pathway in Arabidopsis thaliana with 35S::MIM156 (via target mimicry) increased the sensitivity of the plant to stress treatment, whereas overexpression of miR156 increased stress tolerance. In fact, this mechanism is also conserved in Oryza sativa (rice). We also identified downstream genes of miR156, i.e. SQUAMOSA PROMOTER BINDING PROTEIN‐LIKE 9 (SPL9) and DIHYDROFLAVONOL‐4‐REDUCTASE (DFR), which take part in this process by influencing the metabolism of anthocyanin. Our results uncover a molecular mechanism for plant adaptation to the environment through the miR156‐SPLs‐DFR pathway, which coordinates development and abiotic stress tolerance.
Grain number and size are interactive agronomic traits that determine grain yield. However, the molecular mechanisms responsible for coordinating the trade-off between these traits remain elusive. ...Here, we characterized the rice (Oryza sativa) grain size and number1 (gsn1) mutant, which has larger grains but sparser panicles than the wild type due to disordered localized cell differentiation and proliferation. GSN1 encodes the mitogen-activated protein kinase phosphatase OsMKP1, a dual-specificity phosphatase of unknown function. Reduced expression of GSN1 resulted in larger and fewer grains, whereas increased expression resulted in more grains but reduced grain size. GSN1 directly interacts with and inactivates the mitogen-activated protein kinase OsMPK6 via dephosphorylation. Consistent with this finding, the suppression of mitogen-activated protein kinase genes OsMPK6, OsMKK4, and OsMKKK10 separately resulted in denser panicles and smaller grains, which rescued the mutant gsn1 phenotypes. Therefore, OsMKKK10-OsMKK4-OsMPK6 participates in panicle morphogenesis and acts on a common pathway in rice. We confirmed that GSN1 is a negative regulator of the OsMKKK10-OsMKK4-OsMPK6 cascade that determines panicle architecture. The GSN1-MAPK module coordinates the trade-off between grain number and grain size by integrating localized cell differentiation and proliferation. These findings provide important insights into the developmental plasticity of the panicle and a potential means to improve crop yields.
Sugar cane bagasse ash (SCBA) is an abundant byproduct of the sugar and ethanol industry. SCBA is generally used as a fertilizer or is disposed of in landfills, which has led to intensified ...environmental concerns. In recent years, SCBA research has mainly been focused on utilization in construction materials due to the abundance and pozzolanic characteristics of SCBA. In this paper, a comprehensive review of the state-of-the-art morphology, physical properties, chemical composition, and mineralogical composition of SCBA is presented. Studies indicate that SCBA is a potentially promising construction material. The applications of SCBA as a pozzolanic material, a new source for preparing alkali-activated binders, aggregates, and fillers in construction materials, are summarized. The impacts of SCBA on fresh and hardened concrete properties are highlighted, including the physical properties, mechanical strength, microstructure, and durability. Key factors that govern pozzolanic activity are discussed in detail, including calcination and recalcination temperatures, and durations, fineness, loss on ignition (LOI), and crystal silicon dioxide. Finally, further research on the optimal and broad utilization of SCBA in construction materials is recommended.
Let X and X∗ be a Banach space and its dual, respectively. In this paper, we study the relations between modulus of W1X∗ε and modulus ζX∗ε in X∗ and normal structure in X, respectively. Among other ...results, we proved either W1X∗ε<ε/2, for any 0≤ε≤2, or ζX∗ε<1+ε, for any 0≤ε≤1, implies both X and its dual X∗ have uniform normal structure.
Organic ferroelectrics are highly desirable for their light weight, mechanical flexibility and biocompatibility. However, the rational design of organic ferroelectrics has always faced great ...challenges. Anilinium bromide (AB) has two structures reported in the Cambridge Crystallographic Data Centre, which might be an mmmF2/m type ferroelastic (AB‐1). When we studied its ferroelasticity, we were surprised to discover that there was another crystal (AB‐2) in H2O besides this one, and they were very difficult to separate. By changing the solvent, we found that AB‐1 crystals could be formed in ethanol, where ferroelastic domains were visualized by polarized light microscopy, and AB‐2 crystals could be obtained from various crystallization solvents of methanol, isopropanol, N‐butanol, acetonitrile, dimethyl sulfoxide, and N,N‐dimethylformamide, which undergo a ferroelectric phase transition with mm2Fm, showing clear ferroelectricity in two phases. To our knowledge, the regulation of ferroelasticity to ferroelectricity by solvent selective effect is unprecedented in the field of ferroelectrics. This work reveals the important role of solvent effect in organic ferroelectrics.
A solvent selective effect for the regulation of ferroelasticity and ferroelectricity of anilinium bromide is described, which is unprecedented in organic molecular ferroelectrics. Two forms of crystal structure were obtained from different crystallization solvents: ferroelastic AB‐1 and ferroelectric AB‐2. Atom key: Br (green), N (blue), H (light blue), C (gray).
Increasing vulnerability of crops to a wide range of abiotic and biotic stresses can have a marked influence on the growth and yield of major crops, especially sugarcane (
spp.). In response to ...various stresses, plants have evolved a variety of complex defense systems of signal perception and transduction networks. Transcription factors (TFs) that are activated by different pathways of signal transduction and can directly or indirectly combine with
-acting elements to modulate the transcription efficiency of target genes, which play key regulators for crop genetic improvement. Over the past decade, significant progresses have been made in deciphering the role of plant TFs as key regulators of environmental responses in particular important cereal crops; however, a limited amount of studies have focused on sugarcane. This review summarizes the potential functions of major TF families, such as WRKY, NAC, MYB and AP2/ERF, in regulating gene expression in the response of plants to abiotic and biotic stresses, which provides important clues for the engineering of stress-tolerant cultivars in sugarcane.
Inspired by green plants, artificial photosynthesis has become one of the most attractive approaches toward carbon dioxide (CO2) valorization. Semiconductor quantum dots (QDs) or dot‐in‐rod (DIR) ...nano‐heterostructures have gained substantial research interest in multielectron photoredox reactions. However, fast electron–hole recombination or sluggish hole transfer and utilization remains unsatisfactory for their potential applications. Here, the first application of a well‐designed ZnSe/CdS dot‐on‐rods (DORs) nano‐heterostructure for efficient and selective CO2 photoreduction with H2O as an electron donor is presented. In‐depth spectroscopic studies reveal that surface‐anchored ZnSe QDs not only assist ultrafast (≈2 ps) electron and hole separation, but also promote interfacial hole transfer participating in oxidative half‐reactions. Surface photovoltage (SPV) spectroscopy provides a direct image of spatially separated electrons in CdS and holes in ZnSe. Therefore, ZnSe/CdS DORs photocatalyze CO2 to CO with a rate of ≈11.3 µmol g−1 h−1 and ≥85% selectivity, much higher than that of ZnSe/CdS DIRs or pristine CdS nanorods under identical conditions. Obviously, favored energy‐level alignment and unique morphology balance the utilization of electrons and holes in this nano‐heterostructure, thus enhancing the performance of artificial photosynthetic solar‐to‐chemical conversion.
A dot‐on‐rod (DOR) nano‐heterostructure is rationally constructed by anchoring multiple ZnSe QDs on a single CdS nanorod. Due to the favored energy level alignment and the good exposure of ZnSe to the surrounding medium, ultrafast (≈2 ps) charge separation and facile hole utilization are realized, which enable effective and selective CO2‐to‐CO photoreduction taking H2O as an electron donor.
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