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Let A be a unital *-algebra with the unit I and a nontrivial projection PεA. Suppose that A satisfies XAP = 0 implies X = 0 and XA(I - P)= 0 implies X = 0. In this paper, we prove that ϕ is a nonlinear A* B + B*A type derivation on A if and only if ϕ is an additive *-derivation. This is then applied to prime *-algebra, von Neumann algebras with no central summands of type I1, factor von Neumann algebras and standard operator algebras. [ABSTRACT FROM AUTHOR]

Water level fluctuation and inorganic nitrogen enrichment are two serious problems caused by anthropogenic disturbances in aquatic ecosystems. They cause resource fluctuation and thus might influence the invasive-ness of alien plants. Alternanthera philoxeroides is an amphibious and widespread clonal plant which exhibits significant invasiveness. This experimental study examined the plant's morphological traits under different nitrogen concentrations and water levels. The responses of A. philoxeroides to water levels and nitrogen concentrations were similar for both land-like and riverbank-like initial conditions. A. philoxeroides showed an escape strategy of shoot elongation when its growth was suppressed by shallow submergence. No toxic symptoms but increased clonal spread was observed at high nitrogen concentrations, suggesting that A. philoxeroides not only tolerated but benefitted from nitrogen-polluted water. High nitrogen level mitigated the negative effects of submergence on its leaf survival, thereby enhancing its adaptation to water level fluctuation. Such strong adaptability and clonal spread helps A. philoxeroides to grow and invade successfully in shallow eutrophic water. [ABSTRACT FROM AUTHOR]

Dihydroflavanol-4-reductase (Dfr) is a key enzyme that regulates the synthesis of anthocyanin and proanthocyanidin in the flavonoid biosynthesis pathway. To investigate the difference of dfr gene in Scutellaria baicalensis Georgi with different colors in the same ecological environment, three complete full-length sequences of dfr gene were cloned from the cDNA of S. baicalensis with white, purple-red and purple colors using homologous cloning and RACE techniques. The three genes were named Sbdfr1, Sbdfr2 and Sbdfr3, respectively, and their corresponding structures were analyzed. The results showed that all three Dfr proteins have highly conserved NADPH binding sites and substrate-specific binding sites. Phylogenetic analysis showed that they are closely related to that of the known S. viscidula (ACV49882.1). Analysis of key structural domains and 3D models revealed differences in the catalytically active regions on the surface of all three Dfr proteins, and their unique structural characteristics may provide favorable conditions for studying the substrate specificity of different Dfr proteins. qRT-PCR analysis shows that dfr was expressed at different level in all tissues except the roots of S. baicalensis in full-bloom. During floral development, the expression level of dfr in white and purple-flowered Scutellaria showed an overall upward trend. In purple-red-flowered Scutellaria, the expression first slowly increased, followed by a decrease, and then rapidly increased to the maximum. This research provides a theoretical basis for further exploring the mechanism and function of Dfr substrate selectivity, and are of great scientific value for elucidating the molecular mechanism of floral color variation in S. baicalensis.

Network structures assembled from α-Fe 2 O 3 nanosheets with exposed {104} facets were successfully prepared by heating Fe(NO 3 ) 3 solution containing polyvinylpyrrolidone (PVP) in air. The α-Fe 2 O 3 nanosheet-based network structures demonstrate significantly higher response to ethanol and triethylamine than α-Fe 2 O 3 commercial powders. The excellent sensing performances can be ascribed to the exposed (104) facet terminated with Fe atoms. A concept of the unsaturated Fe atoms serving as the sensing reaction active sites is thus proposed, and the sensing reaction mechanism is described at the atomic and molecular level for the first time in detail. The concept of the surface metal atoms with dangling bonds serving as active sites can deepen understanding of the sensing and other catalytic reaction mechanisms and provides new insight into the design and fabrication of highly efficient sensing materials, catalysts, and photoelectronic devices.