Topological structures based on controllable ferroelectric or ferromagnetic domain configurations offer the opportunity to develop microelectronic devices such as high-density memories. Despite the increasing experimental and theoretical insights into various domain structures (such as polar spirals, polar wave, polar vortex) over the past decade, manipulating the topological transformations of polar structures and comprehensively understanding its underlying mechanism remains lacking. By conducting an in-situ non-contact bias technique, here we systematically investigate the real-time topological transformations of polar structures in PbTiO3/SrTiO3 multilayers at an atomic level. The procedure of vortex pair splitting and the transformation from polar vortex to polar wave and out-of-plane polarization are observed step by step. Furthermore, the redistribution of charge in various topological structures has been demonstrated under an external bias. This provides new insights for the symbiosis of polar and charge and offers an opportunity for a new generation of microelectronic devices.

mircoRNAs (miRNAs) play important roles on regulation of gene expressions. Aberrant expression of miRNAs was involved in various biological and pathological processes, including tumorigenesis of breast cancer. Single-nucleotide polymorphisms (SNPs) were implicated in altered expression or biological functions of mature miRNAs. To explore the relevance of miRNA polymorphisms and female physiological characteristics to breast cancer risk, SNPs located within hsa-miR-605 (rs2043556), hsa-miR-149 (rs2292832), hsa-miR-27a (rs895819), hsa-miR-196a-2 (rs11614913) and hsa-miR-618 (rs2682818) were selected, and their associations with breast cancer risk were analysed. In addition, associations between physiological characteristics-related factors and breast cancer risk were estimated too. We found that the ones with menarche age less than 16 years had increased breast cancer risk (OR = 2.10, 95% CI: 1.23-3.60). Marginally significant association between rs11614913 CT/CC genotypes and reduced breast cancer risk was observed (OR = 0.65, 95% CI: 0.40-1.06), while no significance was detected about the other miRNA polymorphisms. We concluded that menarche at less than 16 years old increased breast cancer risk, while the genetic variants in miR-196-a-2 might decrease the risk.

The effects and mechanisms of Paenibacillus polymyxa Sx3 on growth promotion and the suppression of bacterial leaf blight in rice were evaluated in this study. The results from a plate assay indicated that Sx3 inhibited the growth of 20 strains of Xanthomonas oryzae pv. oryzae (Xoo). Rice seedling experiments indicated that Sx3 promoted plant growth and suppressed bacterial leaf blight. In addition, bacteriological tests showed that Sx3 was able to fix nitrogen, solubilize phosphate and produce indole acetic acid, indicating that various mechanisms may be involved in the growth promotion by Sx3. The culture filtrate of P. polymyxa Sx3 reduced bacterial growth, biofilm formation and disrupted the cell morphology of Xoo strain GZ 0005, as indicated by the transmission and scanning electron microscopic observations. In addition, MALDI‐TOF MS analysis revealed that Sx3 could biosynthesize two types of secondary metabolites fusaricidins and polymyxin P. In summary, this study clearly indicated that P. polymyxa Sx3 has strong in vitro and in vivo antagonistic activity against Xoo, which may be at least partially attributed to its production of secondary metabolites. Significance and Impact of the Study Antagonistic bacteria can grow well in their originating environment. However, it is unclear whether antagonistic bacteria were able to survive in different ecological environments. This study revealed that Paenibacillus polymyxa Sx3 isolated from rhizosphere soil of cotton significantly promoted the plant growth and suppressed bacterial leaf blight in rice. Therefore, it could be inferred that P. polymyxa Sx3 has the potential to be used as biocontrol agents in plants grown in different ecological environments.

Copper (Cu) and zinc (Zn) transport after agricultural applications have accumulated in the sediments and are suspected to affect fish health in the Indian River Lagoon and St. Lucie Estuary, South Florida. Minimal information is available on the release of soil Cu and Zn to water and its relation to their concentrations and physicochemical forms in the soils. Sandy soil samples (n = 13) with a wide range of total Cu and Zn content were collected from forestland and commercial citrus groves in the Indian River area, Florida. The soils were subjected to column leaching and batch extractions to understand the release behavior of Cu and Zn as affected by soil‐water contact time, soil/water ratio, pH, and electrolyte concentration and cations. Copper released in batch extractions that simulated long‐term leaching was primarily from exchangeable and carbonate‐bound fractions, whereas Zn was primarily from the carbonate‐bound fraction. The Cu and Zn released from the column represented short‐term leaching and were primarily from their exchangeable fractions. Leached Zn decreased linearly as the solution pH was raised from 3.0 to 9.0. Leached Cu was at a minimum at pH 5 to 7 and increased at higher or lower pH beyond that range. These results indicate that long‐term saturated conditions after precipitation enhanced Cu and Zn release to water from the sandy soils. The released Cu decreased with increasing Ca concentration but increased with sodium (Na) concentration in the soil solution because of their differential effects on soil colloids, especially organic matter (flocculated by Ca2+ and dispersed by Na+) because organically bound Cu is the dominant fraction in the soils. Increasing Ca, K, Na, or NH4+ concentration generally increased Zn release through cation exchange. These findings merit attention in the development of best management practices to reduce transport of heavy metals from land to water.