154 research outputs found

    Matrix Formulation of Hamiltonian Structures of Constrained KP Hierarchy

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    We give a matrix formulation of the Hamiltonian structures of constrained KP hierarchy. First, we derive from the matrix formulation the Hamiltonian structure of the one-constraint KP hierarchy, which was originally obtained by Oevel and Strampp. We then generalize the derivation to the multi-constraint case and show that the resulting bracket is actually the second Gelfand-Dickey bracket associated with the corresponding Lax operator. The matrix formulation of the Hamiltonian structure of the one-constraint KP hierarchy in the form introduced in the study of matrix model is also discussedComment: 19 pages, Revtex, no figures. Minor changes, reference correcte

    Bis{2-meth­oxy-6-[(3-methoxy­prop­yl)imino­meth­yl]phenolato-κ2 N,O 1}copper(II)

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    The title complex, [Cu(C12H16NO3)2], adopts a distorted square-planar coordination geometry with the CuII ion situated on a crystallographic inversion center. The two Schiff base ligands are coordinated in a trans fashion. In the crystal structure, non-classical inter­molecular C—H⋯O hydrogen bonds involving the ether O atoms link the Schiff base mol­ecules into a two-dimensional network parallel to (101)

    ProKware: integrated software for presenting protein structural properties in protein tertiary structures

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    Protein tertiary structure plays an essential role in deciphering protein functions, especially protein structural properties, including domains, active sites and post-translational modifications. These properties typically yield useful clues for understanding protein functions. This work presents an integrated software, named ProKware, that presents protein structural properties in protein tertiary structures, such as domains, functional sites, families, active sites, binding sites, post-translational modifications and domain–domain interaction. Using this web-based and Windows-based interface, users can manipulate and visualize three-dimensional protein structures, as well as the supported structural properties that are curated in the protein knowledge database. ProKware is an effective and convenient solution for investigating protein functions and structural relationships. This software can be accessed on the internet at

    End-to-end thiocyanato-bridged helical chain polymer and dichlorido-bridged copper(II) complexes with a hydrazone ligand: synthesis, characterisation by electron paramagnetic resonance and variable- temperature magnetic studies, and inhibitory effects on human colorectal carcinoma cells

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    The reactions of the tridentate hydrazone ligand, N’-[1-(pyridin-2-yl)ethylidene]acetohydrazide (HL), obtained by condensation of 2-acetylpyridine with acetic hyadrazide, with copper nitrate trihydrate in the presence of thiocyanate, or with CuCl2 produce two distinct coordination compounds, namely a one-dimensional helical coordination chain of [CuL(NCS)]n (1) units, and a doubly chlorido-bridged dinuclear complex [Cu2L2Cl2] (2) (where L=CH3C(O)=N − N=CCH3C5H4N). Single-crystal X-ray structural determination studies reveal that in complex 1, a deprotonated hydrazone ligand L- coordinates a copper(II) ion that is bridged to two neighbouring metal centres by SCN- anions, generating a one-dimensional helical coordination chain. In complex 2, two symmetry-related, adjacent copper(II) coordination entities are doubly chlorido-bridged, producing a dicopper entity with a Cu···Cu distance of 3.402 (1). The two coordination compounds have been fully characterised by elemental analysis, spectroscopic techniques including IR, UV– vis and electron paramagnetic resonance, and variable-temperature magnetic studies. The biological effects of 1 and 2 on the viability of human colorectal carcinoma cells (COLO-205 and HT-29) were evaluated using an MTT assay, and the results indicate that these complexes induce a decrease in cell-population growth of human colorectal carcinoma cells with apoptosis

    Dichlorido{N′-[(pyridin-2-yl)methyl­idene-κN]acetohydrazide-κ2 N′,O}copper(II)

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    In the title compound, [CuCl2(C8H9N3O)], the CuII atom has a distorted square-pyramidal CuCl2N2O coordination geometry. The tridentate acetohydrazide ligand occupies three basal positions, the fourth basal position being defined by a chloride anion at a distance of 2.2116 (6) Å. The second chloride anion is in the apical position and forms a longer Cu—Cl distance of 2.4655 (7) Å. Inter­molecular N—H⋯Cl hydrogen bonds are present in the crystal, leading to the formation of chains along [10]

    Azido­(benzoyl­acetonato-κ2 O,O′)[1-phenyl-3-(2-pyridylmethyl­imino)but-1-en-1-olato-κ3 N,N′,O]cobalt(III)

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    In the title complex, [Co(C16H15N2O)(C10H9O2)(N3)], the CoII atom adopts an octa­hedral coordination geometry by a tridentate Schiff base, a bidentate benzoyl­acetonate and an azide ligand. The imine N atom of the tridentate ligand is trans to the benzoyl O atom of the bidentate ligand and the azide ligand is trans to the acetyl O atom of the bidentate ligand. Non-classical intra­molecular Car­yl—H⋯O hydrogen bonds are present in the structure

    dbPTM: an information repository of protein post-translational modification

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    dbPTM is a database that compiles information on protein post-translational modifications (PTMs), such as the catalytic sites, solvent accessibility of amino acid residues, protein secondary and tertiary structures, protein domains and protein variations. The database includes all of the experimentally validated PTM sites from Swiss-Prot, PhosphoELM and O-GLYCBASE. Only a small fraction of Swiss-Prot proteins are annotated with experimentally verified PTM. Although the Swiss-Prot provides rich information about the PTM, other structural properties and functional information of proteins are also essential for elucidating protein mechanisms. The dbPTM systematically identifies three major types of protein PTM (phosphorylation, glycosylation and sulfation) sites against Swiss-Prot proteins by refining our previously developed prediction tool, KinasePhos (). Solvent accessibility and secondary structure of residues are also computationally predicted and are mapped to the PTM sites. The resource is now freely available at

    A mixed valent heterometallic Cu-II/Na-I coordination polymer with sodium-phenyl bonds

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    A mixed valent heterometallic Cu/Na coordination polymer (1) is generated by the reaction of a Schiff base ligand, (6,6′-(1E,1′E)-(2-hydroxypropane-1,3-diyl)bis(azan-1-yl-1-ylidene) bis(methan-1-yl-1-ylidene)bis(2-methoxyphenol)) with copper(ii) acetate and sodium perchlorate. In addition to the presence of alcohol oxygen-sodium coordination bonds, the single crystal X-ray structure reveals that the 1D coordination polymer is stabilised by the formation of phenyl-sodium η-bonds, face-to-face π-π contacts and Cu-π interactions. This journal i
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