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Detecting land cover change through very-high-resolution (VHR) remote sensing images is helpful in supporting urban sustainable development, natural disaster evaluation, and environmental assessment. However, the intraclass spectral variance in VHR remote sensing images is usually larger than that of median-low remote sensing images. Furthermore, the bitemporal images are usually acquired under different atmospheric conditions, sun height, soil moisture, and other factors. Consequently, in practical applications, many pseudo changes are presented in the detected map. In this paper, an adaptive histogram trend (AHT) similarity approach is promoted to quantitatively measure the magnitude between the corresponding pixels in bitemporal images in terms of change semantic. In the proposed approach, to reduce the phenological effect on the bitemporal images of land cover change detection (LCCD), we first define the quantitative description of AHT. Second, the change magnitudes between pairwise pixels are quantitatively measured by an improved bin-to-bin (B2B) distance between the corresponding AHTs. Then, the change magnitudes between two entire bitemporal images are measured AHT-by-AHT. Finally, binary threshold methods, such as the Otsu method or the double-window flexible pace search (DFPS) method, are used to divide the change magnitude image into binary change detection maps and obtain the final change detection map. The performance of the AHT-based LCCD approach is verified by four pairs of VHR remote-sensing images that correspond to two types of real land cover change cases. The detected results based on the four pairs of bitemporal VHR images outperformed the compared state-of-the-art LCCD methods. [ABSTRACT FROM AUTHOR]

A novel Cu(II) mixed-ligand complex, {[Cu(sq)(L)(H2O)]· 0.9H2O}n (1) (sq = squarate dianion, L = 5,5′-dimethyl-2,2′-bipyridine), has been synthesized and characterized by elemental analyses, infrared (IR), and X-ray single-crystal diffraction. In 1, each copper(II) ion has a five-coordinated environment with square pyramidal geometry. A one-dimensional (1D) chain structure of the complex is constructed by squarate in μ-1,2-bis(monodentate) coordination mode and further forms a two-dimensional (2D) framework via “metal chelate–metal chelate ring” π–π stacking interactions between the adjacent chains. This unexpected π–π stacking interaction provides structural evidence for the metalloaromaticity of the Cu(II)-(aromatic α,α′-diimines) chelate rings. [ABSTRACT FROM PUBLISHER]

Summary In the developing brain, immature synapses contain calcium-permeable AMPA glutamate receptors (AMPARs) that are subsequently replaced with GluA2-containing calcium-impermeable AMPARs as synapses stabilize and mature. Here, we show that this essential switch in AMPARs and neuronal synapse maturation is regulated by astrocytes. Using biochemical fractionation of astrocyte-secreted proteins and mass spectrometry, we identified that astrocyte-secreted chordin-like 1 (Chrdl1) is necessary and sufficient to induce mature GluA2-containing synapses to form. This function of Chrdl1 is independent of its role as an antagonist of bone morphogenetic proteins (BMPs). Chrdl1 expression is restricted to cortical astrocytes in vivo , peaking at the time of the AMPAR switch. Chrdl1 knockout (KO) mice display reduced synaptic GluA2 AMPARs, altered kinetics of synaptic events, and enhanced remodeling in an in vivo plasticity assay. Studies have shown that humans with mutations in Chrdl1 display enhanced learning. Thus astrocytes, via the release of Chrdl1, promote GluA2-dependent synapse maturation and thereby limit synaptic plasticity. Highlights • Astrocytes regulate synapse maturation by controlling AMPA receptor subtype • Astrocyte-secreted Chrdl1 increases synaptic levels of GluA2 AMPA receptors • Chrdl1 KO mice have immature synapses • Chrdl1 KO mice show enhanced plasticity in vivo , which is maintained into adulthood Blanco-Suarez et al. identify that synapse maturation is not intrinsic to neurons but is regulated by neighboring astrocytes. They demonstrate that astrocyte-secreted Chrdl1 increases GluA2 AMPA receptor levels at synapses, inducing synapse maturation and inhibiting plasticity. [ABSTRACT FROM AUTHOR]

A novel one-dimensional (1D) helical chain polymer, {[CoL2(H2O)](H3O)(ClO4)}n (1) (HL = 4-N-(2′-pyridylimine)benzoic acid), was synthesized by reaction of Co(II) perchlorate with L anion in ethanol solution, and characterized by element analyses, infrared spectroscopy, and X-ray single-crystal diffraction. In this structure, the Co2+ ion is in a distorted octahedral geometry, an infinite 1D helical chain was constructed by L ligand through bidentate-monodentate bridging modes and are further assembled into three-dimensional supramolecular networks through complicated O–H···O hydrogen bonding interactions. [ABSTRACT FROM PUBLISHER]

Two novel zinc coordination polymers {[Zn(PhCOO)2(bmix)]}n 1 and {[Zn(ada)(bmix)]·(H2O)2}n 2 (bmix = 1,4-bis(2-methylimidazole-1-ylmethyl)benzene, H2ada = adipic acid), were obtained by the hydrothermal reactions of bmix and zinc acetate with two carboxylate anions, respectively. Structural analyses show that complex 1 possess a one-dimensional helix chain structure, 2 takes two-dimensional corrugated (4,4) layer motif. The structural differences of two complexes indicate that organic carboxylate anions play important roles in the formation of such zinc(II) coordination architectures. [ABSTRACT FROM AUTHOR]

Abstract: A mononuclear copper(II) complex, [Cu(PIM)2(PhCOO)2] (1) [where PIM=2-propylimidazole] has been synthesized and characterized by elemental analysis, IR, UV–Vis, TGA, and single crystal X-ray diffraction. The structural analysis indicated that Cu(II) atom in the complex is six-coordinated in a distorted octahedral geometry by two N atoms from two 2-propylimidazole and four O atoms from two benzoate ligands. In addition, based on crystal structural data, quantum chemistry calculation in DFT/B3LYP level has been used to reoptimize and explore the electronic structure of the compound 1; time-dependent DFT (TD-DFT) calculations have also been performed in order to elucidate its spectroscopic properties. All parameters from the calculations are in well accordance with our experimental result. [Copyright &y& Elsevier]