Nonreducing Ambient Atmosphere: Pulsed Electric Current Treatment of Co/Ni Doped Perovskite Oxides to Achieve Exsolution Enhanced Electrochemical Performance.

Exsolution of metal nanoparticles (NPs) on the surface of perovskite oxides is a promising approach for developing advanced catalytic materials through a "bottom-up" design strategy. Under a nonreducing ambient atmosphere utilizing pulsed electric current (PEC) treatment to promote the exsolution of perovskite oxides effectively overcomes the limitations inherent in conventional high-temperature vapor phase reduction (HTVPR) in situ exsolution methods. This paper presents the successful synthesis of (La0.7Sr0.3)0.8Ti0.93Ni0.07O3 (LSTN) perovskite oxide and (La0.7Sr0.3)0.8Ti0.93Co0.07O3 (LSTC) perovskite oxide using the sol-gel method, followed by PEC treatment at 600 V, 3 Hz, and 90 s. Utilizing various characterization techniques to confirm that PEC treatment can promote the exsolution of Co and Ni NPs under a nonreducing ambient atmosphere, the results indicated that the exsolved perovskite oxides exhibited significantly improved electrochemical properties. Furthermore, compared to the LSTN-PEC, LSTC-PEC demonstrates a lower onset potential of 1.504 V, a Tafel slope of 87.16 mV dec-1, lower impedance, higher capacitance, superior catalytic activity, and long-term stability.

Epigenetic regulation of female germline development through ERECTA signaling pathway.

Germline development is a key step in sexual reproduction. Sexual plant reproduction begins with the formation of haploid spores by meiosis of megaspore mother cells (MMCs). Although many evidences, directly or indirectly, show that epigenetics plays an important role in MMC specification, how it controls the commitment of the MMC to downstream stages of germline development is still unclear. Electrophoretic mobility shift assay (EMSA), western blot, immunofluorescence, and chromatin immunoprecipitation coupled with quantitative PCR analyses were performed. Genetic interactions between BZR1 transcription factor family and the SWR1-SDG2-ER pathway in the control of female germline development were further studied. The present findings showed in Arabidopsis that two epigenetic factors, the chromatin remodeling complex SWI2/SNF2-RELATED 1 (SWR1) and a writer for H3K4me3 histone modification SET DOMAIN GROUP 2 (SDG2), genetically interact with the ERECTA (ER) receptor kinase signaling pathway and regulate female germline development by restricting the MMC cell fate to a single cell in the ovule primordium and ensure that only that single cell undergoes meiosis and subsequent megaspore degeneration. We also showed that SWR1-SDG2-ER signaling module regulates female germline development by promoting the protein accumulation of BZR1 transcription factor family on the promoters of primary miRNA processing factors, HYPONASTIC LEAVES 1 (HYL1), DICER-LIKE 1 (DCL1), and SERRATE (SE) to activate their expression. Our study elucidated a Gene Regulation Network that provides new insights for understanding how epigenetic factors and receptor kinase signaling pathways function in concert to control female germline development in Arabidopsis.

Identification of GA2ox Family Genes and Expression Analysis under Gibberellin Treatment in Pineapple (Ananas comosus (L.) Merr.).

Gibberellin (GAs) plays an important regulatory role in the development and growth of pineapple (Ananas comosus (L.) Merr.). Bioinformatics was used to confirm the differential expression of GA2 gibberellin oxidase gene AcGA2oxs in the pineapple genome, which laid the foundation for exploring its role in pineapple. In this study, 42 GA2ox genes (AcGA2oxs) were identified in the pineapple genome, named from AcGA2ox1 to AcGA2ox42, and divided into four groups according to phylogenetic analysis. We also analyzed the gene structure, conserved motifs and chromosome localization of AcGA2oxs. AcGA2oxs within the same group had similar gene structure and motifs composition. Collinear analysis and cis-element analysis provided the basis for understanding the evolution and function of GA2ox genes in pineapple. In addition, we selected different tissue parts to analyze the expression profile of AcGA2oxs, and the results show that 41 genes were expressed, except for AcGA2ox18. AcGA2ox18 may not be expressed in these sites or may be pseudogenes. qRT-PCR (real-time fluorescence quantitative PCR) was used to detect the relative expression levels of the GA2ox gene family under different concentrations of GA3 treatment, and it was found that AcGA2ox gene expression was upregulated in different degrees under GA3 treatment. These results provide useful information for further study on the evolution and function of the GA2ox family in pineapple.

Signaling by the EPFL-ERECTA family coordinates female germline specification through the BZR1 family in Arabidopsis.

In most flowering plants, the female germline is initiated in the subepidermal L2 layer of ovule primordia forming a single megaspore mother cell (MMC). How signaling from the L1 (epidermal) layer could contribute to the gene regulatory network (GRN) restricting MMC formation to a single cell is unclear. We show that EPIDERMAL PATTERNING FACTOR-like (EPFL) peptide ligands are expressed in the L1 layer, together with their ERECTA family (ERf) receptor kinases, to control female germline specification in Arabidopsis thaliana. EPFL-ERf dependent signaling restricts multiple subepidermal cells from acquiring MMC-like cell identity by activating the expression of the major brassinosteroid (BR) receptor kinase BRASSINOSTEROID INSENSITIVE 1 and the BR-responsive transcription factor BRASSINOZOLE RESISTANT 1 (BZR1). Additionally, BZR1 coordinates female germline specification by directly activating the expression of a nucleolar GTP-binding protein, NUCLEOSTEMIN-LIKE 1 (NSN1), which is expressed in early-stage ovules excluding the MMC. Mutants defective in this GRN form multiple MMCs resulting in a strong reduction of seed set. In conclusion, we uncovered a ligand/receptor-like kinase-mediated signaling pathway acting upstream and coordinating BR signaling via NSN1 to restrict MMC differentiation to a single subepidermal cell.

A novel exsolution technique-twice lasers: rapidly aroused explosive exsolution of nanoparticles to boost electrochemical performance.

The exsolution of nanoparticles (NPs) on material surfaces exhibits good performance with great potential in the field of catalysis. In this study, a method with twice lasers treatment (TLT) is proposed for the first time to rapidly promote the exsolution of Co NPs to the surface of (La0.7Sr0.3)0.93Ti0.93Co0.07O3(LSTC) by laser rapid heating to enhance the electrochemical performance of the LSTC. The entire process from precursor powder-stable perovskite crystal structure-Co NPs exsolution on the LSTC surface takes only ≈36 s by TLT. The Co NPs exsolution was confirmed by x-ray diffractometer, scanning electron microscopy and high-resolution transmission electron microscopy. After TLT, a large number of Co NPs reached 75 particlesµm-2appeared on the surface of LSTC with the onset potential of 1.38 V, the overpotential of 214 mV, and the Tafel slope of 81.14 mV dec-1, showing good catalytic activity and long-term stability. The novel process of using TLT to rapidly induce exsolution of NPs enables the rapid preparation of nanoparticle-decorated perovskite materials with better electrochemical properties, thus enriching exsolution technology and opening a new avenue for surface science research.

Ectopic Overexpression of Pineapple Transcription Factor AcWRKY31 Reduces Drought and Salt Tolerance in Rice and Arabidopsis.

Pineapple (Ananas comosus (L.) Merr.) is an important tropical fruit with high economic value, and its growth and development are affected by the external environment. Drought and salt stresses are common adverse conditions that can affect crop quality and yield. WRKY transcription factors (TFs) have been demonstrated to play critical roles in plant stress response, but the function of pineapple WRKY TFs in drought and salt stress tolerance is largely unknown. In this study, a pineapple AcWRKY31 gene was cloned and characterized. AcWRKY31 is a nucleus-localized protein that has transcriptional activation activity. We observed that the panicle length and seed number of AcWRKY31 overexpression transgenic rice plants were significantly reduced compared with that in wild-type plant ZH11. RNA-seq technology was used to identify the differentially expressed genes (DEGs) between wild-type ZH11 and AcWRKY31 overexpression transgenic rice plants. In addition, ectopic overexpression of AcWRKY31 in rice and Arabidopsis resulted in plant oversensitivity to drought and salt stress. qRT-PCR analysis showed that the expression levels of abiotic stress-responsive genes were significantly decreased in the transgenic plants compared with those in the wild-type plants under drought and salt stress conditions. In summary, these results showed that ectopic overexpression of AcWRKY31 reduced drought and salt tolerance in rice and Arabidopsis and provided a candidate gene for crop variety improvement.

A-site deficient La0.52Sr0.28Ti0.94Ni0.06O3by low-pulsed electric current treatment: achieved exsolution of B-site Ni nanoparticles and significant improvement of electrocatalytic properties.

Perovskite materials with exsolved nanoparticles have a wide range of applications in energy conversion systems owing to their unique basal plane active sites and excellent catalytic properties. The introduction of A-site deficiency can help the formation of highly mobile oxygen vacancies and remarkably enhance the reducibility of Ni nanoparticles, thus significantly increasing electronic conductivity and catalytic activity simultaneously. Herein, we adopt pulsed electric current (PEC) treatment, a novel approach instead of the long-time high-temperature reduction technique, and for the first time review that the exsolution of minuscule Ni nanoparticles (8-20 nm) could be facilitated on Ni-doped La0.52Sr0.28Ti0.94Ni0.06O3(LSTN) anodes with A-site deficiency. Encouragingly, finding that low PEC can successfully lead to nanoparticle exsolution and show a significantly improved oxygen evolution reaction performance of LSTN-PEC (LSTN after PEC treatment) possessing A-site deficiency, the onset potential of LSTN-PEC (500 V) (LSTN after PEC treatment with 500 V-4 Hz-90 s) was advanced by 0.173 V, theRctvalue was reduced by 82.38 Ω·cm2, and the overpotential was also reduced by 73 mV.

Brassinosteroid signaling regulates female germline specification in Arabidopsis.

Unlike in humans and animals, plant germlines are specified de novo from somatic cells in the reproductive organs of the flower. In most flowering plant ovules, the female germline starts with the differentiation of one megaspore mother cell (MMC), which initiates a developmental program distinct from adjoining cells. Phytohormones act as a key player in physiological processes during plant development, in particular by providing positional information that supports localized differentiation events. However, little is known about the role of phytohormones for female germline initiation and establishment. Using Arabidopsis as a flowering plant model, we show that brassinosteroid (BR) biosynthesis and signaling components are accumulated in sporophytic cells of ovule primordia but not in the megaspore mother cell representing the precursor of the female germline. We further demonstrate that BR signaling restricts multiple sub-epidermal cells in the distal nucellus region of ovule primordia from acquiring MMC-like cell identity by transiently activating the WRKY23 transcription factor, expressed exclusively in L2 layer cells adjacent to the MMC. This activation is regulated through the BRI1 receptor and directly by the BZR1 transcriptional repressor family. Mutations in BR biosynthesis or signaling components and ectopic activation of BR signaling in MMCs induce multiple MMC-like cells. In summary, our findings elucidate a gene regulatory network that shows how the hormone BR generated in sporophytic ovule primordia cells restricts the origin of the female germline to a single cell.

SDG2 regulates Arabidopsis inflorescence architecture through SWR1-ERECTA signaling pathway.

Inflorescence architecture is diverse in flowering plants, and two determinants of inflorescence architecture are the inflorescence meristem and pedicel length. Although the ERECTA (ER) signaling pathway, in coordination with the SWR1 chromatin remodeling complex, regulates inflorescence architecture with subsequent effects on pedicel elongation, the mechanism underlying SWR1-ER signaling pathway regulation of inflorescence architecture remains unclear. This study determined that SDG2 genetically interacts with the SWR1-ER signaling pathways in regulating inflorescence architecture. Transcriptome results showed that auxin might potentially influence inflorescence growth mediated by SDG2 and SWR1-ER pathways. SWR1 and ER signaling are required to enrich H2A.Z histone variant and SDG2 regulated SDG2-mediated H3K4me3 histone modification at auxin-related genes and H2A.Z histone variant enrichment. Our study shows how the regulation of inflorescence architecture is mediated by SDG2 and SWR1-ER, which affects auxin hormone signaling pathways.

Pulsed electric current boosts electrochemical performance and electro-conductivity of La x Sr1-x Cr y Ni1-y O3 perovskite via exsolution of nanoparticles.

In situ exsolved nanoparticles (NPs) on surfaces perform well in many catalytic applications. Herein, an emerging technique of pulsed electric current (PEC) for facilitating NPs exsolution was firstly utilized in functional materials towards tailoring structure and morphology of materials. PEC facilitated Ni NPs exsolution in situ and the exposed active sites were highly dispersed on the LaCrO3 substrate surface. Such result was confirmed by combining x-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy. As a consequence, PEC-treated and untreated LaCrO3 perovskite samples were employed as electrocatalysts for oxygen evolution reaction (OER). The PEC-treated samples exhibit obviously improved OER activity (lower overpotential, smaller Tafel slope) and lower reaction resistance than the untreated samples. This illustrates that the exsolved Ni NPs driven by PEC are beneficial for the OER performance and are probably the components of the OER active sites.

A strategy for controlling degradation in vitro of carbon fiber-reinforced polylactic acid composites (by combining fiber modification and pulsed electromagnetic fields).

Carbon fiber-reinforced polylactic acid (C/PLA) composites are a human bone-fixation material, but control of the material's degradation remains a major factor hindering its widespread use. In this study, a combined method for controlling the degradation performance in vitro of C/PLA composites was designed. In this strategy, carbon fibers for C/PLA composite reinforcement were prepared in both modified and unmodified forms. A pulsed electromagnetic field (PEF) was then selectively applied during the subsequent degradation process. Results and analysis showed that the interfacial ester bonding between modified carbon fibers and PLA matrices significantly affected degradation in vitro of C/PLA composite. However, PEF affected the degradation performance of C/PLA composites and, after PEF treatment, the material's water absorption, mass retention, and bending and shearing strengths were changed to varying degrees. This method, by combining fiber modification and pulsed electromagnetic fields (abbreviated as CMP) provided a new strategy for the controlled degradation of C/PLA composites in human skeletal fixation.

catena-Poly[[diaqua-copper(II)]-µ-hy-drox-ido-κO:O-µ-[4-(4H-1,2,4-triazol-4-yl)benzoato]-κN:N].

The title compound, [Cu(C(9)H(6)N(3)O(2))(OH)(H(2)O)(2)](n), adopts a chain motif along [010] in which the Cu(II) atoms are bridged by hy-droxy groups and 4-(1,2,4-triazol-4-yl)benzoate (tab) ligands. The Cu(II) atom lies on an inversion center and is six-coordinated by two N atoms from two tab ligands, two hy-droxy groups and two water mol-ecules, giving a distorted octa-hedral geometry. The hy-droxy group and the tab ligand are located on a mirror plane. One of the water H atoms is disordered over two positions with equal occupancy factors. Inter-molecular O-H⋯O hydrogen bonds extend the chains into a layer parallel to (100) and C-H⋯O hydrogen bonds connect the layers into a three-dimensional network.