Negative Feedback Regulation of Auxin Signaling by ATHB8/ACL5-BUD2 Transcription Module

The role of auxin as main regulator of vascular differentiation is well established, and a direct correlation between the rate of xylem differentiation and the amount of auxin reaching the （pro）cambial cells has been proposed. It has been suggested that thermospermine produced by ACAULIS5 （ACL5） and BUSHY AND DWARF2 （BUD2） is one of the factors downstream to auxin contributing to the regulation of this process in Arabidopsis. Here, we provide an in-depth characterization of the mechanism through which ACL5 modulates xylem differentiation. We show that an increased level of ACL5 slows down xylem differentiation by negatively affecting the expression of homeodomain-leucine zipper （HD- ZIP） III and key auxin signaling genes. This mechanism involves the positive regulation of thermospermine biosynthesis by the HD-ZIP III protein ARABIDOPSIS THALIANA HOMEOBOX8 tightly controlling the expression of ACL5 and BUD2. In addition, we show that the HD-ZIP III protein REVOLUTA contributes to the increased leaf vascularization and long hypocotyl phenotype of acl5 likely by a direct regulation of auxin signaling genes such as LIKE AUXIN RESISTANT2 （LAX2） and LAX3. We propose that proper formation and differentiation of xylem depend on a balance between positive and negative feedback loops operating through HD-ZIP III genes.

Evidence of Pr^((3+y)+) (y>0)in Infrared Spectra of Pr_xY_(1-x)Ba_2Cu_3O_(7-δ)System

1 Introduction The infrared and Raman spectroscopy are the active tools for studying the lattice vibrations. Since the discovery of high-temperature superconductor, they have been efficiently used to study the novel oxide superconductor. Some key results were obtained to provide proofs for determining the mechanism of superconductivity. The PrxY1-xBa2Cu3O7-δ, is a useful system for studying the high-temperature superconducting mechanism since all

Block-layer model for intergrowth structures

Lattice match and charge transfer between distinct block layers(BLs)play an important role in the formation of an intergrowth structure.Herein we propose a simple BL model addressing the different roles of the lattice match and the charge transfer.Inter-BL charge transfer lowers the internal energy,while lattice match minimizes the elastic energy,both of which together make the intergrowth structure stabilized.The model is able to reproduce the lattice parameters precisely for complex iron-based superconductors with intergrowth structures.The elastic energy and the charge-transfer energy are evaluated with assistance of the first-principles calculations.This work rationalizes the basic principles of BL design for intergrowth structures,which can be utilized not only for finding new superconducting materials but also for investigating other layered materials with various functionalities.

Spontaneous emission in non-local materials

Light–matter interactions can be strongly modified by the surrounding environment.Here,we report on the first experimental observation of molecular spontaneous emission inside a highly non-local metamaterial based on a plasmonic nanorod assembly.We show that the emission process is dominated not only by the topology of its local effective medium dispersion,but also by the non-local response of the composite,so that metamaterials with different geometric parameters but the same local effective medium properties exhibit different Purcell factors.A record-high enhancement of a decay rate is observed,in agreement with the developed quantitative description of the Purcell effect in a non-local medium.An engineered material non-locality introduces an additional degree of freedom into quantum electrodynamics,enabling new applications in quantum information processing,photochemistry,imaging and sensing with macroscopic composites.